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Sung HK, Tang J, Jahng JWS, Song E, Chan YK, Lone AH, Peterson J, Abdul‐Sater A, Sweeney G. Ischemia-induced cardiac dysfunction is exacerbated in adiponectin-knockout mice due to impaired autophagy flux. Clin Transl Sci 2024; 17:e13758. [PMID: 38515365 PMCID: PMC10958170 DOI: 10.1111/cts.13758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 01/23/2024] [Accepted: 02/14/2024] [Indexed: 03/23/2024] Open
Abstract
Strategies to enhance autophagy flux have been suggested to improve outcomes in cardiac ischemic models. We explored the role of adiponectin in mediating cardiac autophagy under ischemic conditions induced by permanent coronary artery ligation. We studied the molecular mechanisms underlying adiponectin's cardio-protective effects in adiponectin knockout (Ad-KO) compared with wild-type (WT) mice subjected to ischemia by coronary artery ligation and H9c2 cardiomyocyte cell line exposed to hypoxia. Systemic infusion of a cathepsin-B activatable near-infrared probe as a biomarker for autophagy and detection via noninvasive three-dimensional fluorescence molecular tomography combined with computerized tomography to quantitate temporal changes, indicated increased activity in the myocardium of WT mice after myocardial infarction which was attenuated in Ad-KO. Seven days of ischemia increased myocardial adiponectin accumulation and elevated ULK1/AMPK phosphorylation and autophagy assessed by Western blotting for LC3 and p62, an outcome not observed in Ad-KO mice. Cell death, assessed by TUNEL analysis and the ratio of Bcl-2:Bax, plus cardiac dysfunction, measured using echocardiography with strain analysis, were exacerbated in Ad-KO mice. Using cellular models, we observed that adiponectin stimulated autophagy flux in isolated primary adult cardiomyocytes and increased basal and hypoxia-induced autophagy in H9c2 cells. Real-time temporal analysis of caspase-3/7 activation and caspase-3 Western blot indicated that adiponectin suppressed activation by hypoxia. Hypoxia-induced mitochondrial reactive oxygen species production and cell death were also attenuated by adiponectin. Importantly, the ability of adiponectin to reduce caspase-3/7 activation and cell death was not observed in autophagy-deficient cells generated by CRISPR-mediated deletion of Atg7. Collectively, our data indicate that adiponectin acts in an autophagy-dependent manner to attenuate cardiomyocyte caspase-3/7 activation and cell death in response to hypoxia in vitro and ischemia in mice.
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Affiliation(s)
| | - Jialing Tang
- Department of BiologyYork UniversityTorontoOntarioCanada
| | | | - Erfei Song
- Department of BiologyYork UniversityTorontoOntarioCanada
| | - Yee Kwan Chan
- Department of BiologyYork UniversityTorontoOntarioCanada
| | | | | | - Ali Abdul‐Sater
- School of Kinesiology and Health ScienceYork UniversityTorontoOntarioCanada
| | - Gary Sweeney
- Department of BiologyYork UniversityTorontoOntarioCanada
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Fedoruk KA, Chan YK, Williams CE. Scholarship in anesthesiology: the role of critical appraisal, literature review, quality improvement, journal club, and presentation skills. Int J Obstet Anesth 2023; 54:103639. [PMID: 36841065 DOI: 10.1016/j.ijoa.2023.103639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/27/2022] [Accepted: 01/29/2023] [Indexed: 02/05/2023]
Abstract
If asked to describe the term "anesthesiologist scholar", one may receive a variety of definitions depending on the individual's area of practice, location in the world, and the generation in which they trained. In this article, we review the roles of five core elements that make an anesthesiologist a "scholar": skills in critical appraisal, literature review, quality improvement, journal club participation, and presentation delivery. Although this list of scholarly components is not comprehensive, review of each element's role in the everyday practice and training of physicians will offer insight into their evolution and may offer a glimpse into the future of anesthesiologist scholars. Overall, through the dissemination, recognition, and support of scholarship through these practices, we will continue to achieve meaningful outcomes for our patients and promote a culture of collaboration worldwide. We should ensure that these topic areas become a bedrock of medical education globally, and we must foster opportunities for those who have already completed training to develop and master these skills as a part of their clinical and academic practice.
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Affiliation(s)
- K A Fedoruk
- Center for Academic Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Palo Alto, CA, USA.
| | - Y K Chan
- Department of Anaesthesiology, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia
| | - C E Williams
- Department of Anaesthesia, Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Hills Road, Cambridge, UK
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Chan YK, Novalo Goto ES, Fachini Jardim Criado R, Criado PR. Allergic contact dermatitis by ophthalmological medications in Brazil: experience of a dermatology department. Eur Ann Allergy Clin Immunol 2021; 53:280-283. [PMID: 33728833 DOI: 10.23822/eurannaci.1764-1489.190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Summary Topical treatments in ophthalmologic therapy are significant for the development of allergic contact dermatitis (ACD) in the periorbital region. Preservatives, antibiotics, glucocorticoids, and beta-blocker eye drops are defined as drugs with the highest sensitizing potential. The unavailability of patch test batteries containing substances of ophthalmological use makes it difficult for this diagnosis. In the present report, we describe six patients who developed ACD induced by different agents presenting in eye drops, confirmed with the cutaneous patch tests. The ACD diagnosis due to ophthalmic medications can be challenging, since many different agents can cause it, and the sensitivity of these cutaneous tests is low. Thus, early diagnosis is essential to avoid the complications of ACD on the skin and ocular disorders related to chronic periorbital eczema.
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Affiliation(s)
- Y K Chan
- Department of Dermatology, Faculdade de Medicina do ABC, Santo André, São Paulo, Brazil
| | - E S Novalo Goto
- Department of Dermatology, Faculdade de Medicina do ABC, Santo André, São Paulo, Brazil
| | | | - P R Criado
- Department of Dermatology, Faculdade de Medicina do ABC, Santo André, São Paulo, Brazil
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Abulizi N, Quin C, Brown K, Chan YK, Gill SK, Gibson DL. Gut Mucosal Proteins and Bacteriome Are Shaped by the Saturation Index of Dietary Lipids. Nutrients 2019; 11:nu11020418. [PMID: 30781503 PMCID: PMC6412740 DOI: 10.3390/nu11020418] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/01/2019] [Accepted: 02/13/2019] [Indexed: 02/07/2023] Open
Abstract
The dynamics of the tripartite relationship between the host, gut bacteria and diet in the gut is relatively unknown. An imbalance between harmful and protective gut bacteria, termed dysbiosis, has been linked to many diseases and has most often been attributed to high-fat dietary intake. However, we recently clarified that the type of fat, not calories, were important in the development of murine colitis. To further understand the host-microbe dynamic in response to dietary lipids, we fed mice isocaloric high-fat diets containing either milk fat, corn oil or olive oil and performed 16S rRNA gene sequencing of the colon microbiome and mass spectrometry-based relative quantification of the colonic metaproteome. The corn oil diet, rich in omega-6 polyunsaturated fatty acids, increased the potential for pathobiont survival and invasion in an inflamed, oxidized and damaged gut while saturated fatty acids promoted compensatory inflammatory responses involved in tissue healing. We conclude that various lipids uniquely alter the host-microbe interaction in the gut. While high-fat consumption has a distinct impact on the gut microbiota, the type of fatty acids alters the relative microbial abundances and predicted functions. These results support that the type of fat are key to understanding the biological effects of high-fat diets on gut health.
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Affiliation(s)
- Nijiati Abulizi
- Department of Biology, IKBSAS, University of British Columbia, Okanagan campus, Kelowna V1V 1V7, Canada.
| | - Candice Quin
- Department of Biology, IKBSAS, University of British Columbia, Okanagan campus, Kelowna V1V 1V7, Canada.
| | - Kirsty Brown
- Department of Biology, IKBSAS, University of British Columbia, Okanagan campus, Kelowna V1V 1V7, Canada.
| | - Yee Kwan Chan
- Department of Biology, IKBSAS, University of British Columbia, Okanagan campus, Kelowna V1V 1V7, Canada.
| | - Sandeep K Gill
- Department of Biology, IKBSAS, University of British Columbia, Okanagan campus, Kelowna V1V 1V7, Canada.
| | - Deanna L Gibson
- Department of Biology, IKBSAS, University of British Columbia, Okanagan campus, Kelowna V1V 1V7, Canada.
- Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver V6T 1Z3, Canada.
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Goh PK, Chiu CL, Wang CY, Chan YK, Loo PL. Randomized Double-blind Comparison of Ketamine-Propofol, Fentanyl-Propofol and Propofol-Saline on Haemodynamics and Laryngeal Mask Airway Insertion Conditions. Anaesth Intensive Care 2019; 33:223-8. [PMID: 15960405 DOI: 10.1177/0310057x0503300211] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of this prospective, double-blind, randomized, placebo-controlled clinical trial was to investigate whether the administration of ketamine before induction with propofol improves its associated haemodynamic profile and laryngeal mask airway (LMA) insertion conditions. Ninety adult patients were randomly allocated to receive either ketamine 0.5 mg.kg-1 (n=30), fentanyl 1 μg.kg-1 (n=30) or normal saline (n=30), before induction of anaesthesia with propofol 2.5 mg.kg-1. Insertion of the LMA was performed 60s after injection of propofol. Arterial blood pressure and heart rate were measured before induction (baseline), immediately after induction, immediately before LMA insertion, immediately after LMA insertion and every minute for three minutes after LMA insertion. Following LMA insertion, the following six subjective endpoints were graded by a blinded anaesthestist using ordinal scales graded 1 to 3: mouth opening, gagging, swallowing, movement, laryngospasm and ease of insertion. Systolic blood pressure was significantly higher following ketamine than either fentanyl (P=0.010) or saline (P=0.0001). The median (interquartile range) summed score describing the overall insertion conditions were similar in the ketamine [median 7.0, interquartile range (6.0–8.0)] and fentanyl groups [median 7.0, interquartile range (6.0–8.0)]. Both appeared significantly better than the saline group [median 8.0, interquartile range (6.75–9.25); P=0.024]. The incidence of prolonged apnoea (>120s) was higher in the fentanyl group [23.1% (7/30)] compared with the ketamine [6.3% (2/30)] and saline groups [3.3% (1/30)]. We conclude that the addition of ketamine 0.5 mg.kg–1 improves haemo-dynamics when compared to fentanyl 1 μg.kg–1, with less prolonged apnoea, and is associated with better LMA insertion conditions than placebo (saline).
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Affiliation(s)
- P K Goh
- Department of Anaesthesia and Intensive Care, Faculty of Medicine, University Malaya Medical Centre, Kuala Lumpur, Malaysia
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Ortolani O, Conti A, Chan YK, Sie MY, Ong GSY. Comparison of Propofol Consumption and Recovery Time in Caucasians from Italy, with Chinese, Malays and Indians from Malaysia. Anaesth Intensive Care 2019; 32:250-5. [PMID: 15957725 DOI: 10.1177/0310057x0403200215] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Differences in sensitivity to anaesthetic drugs may exist among different ethnic groups. Allelic variants for drug metabolizing isoenzymes and pharmacokinetic differences may account for a variable response to some anaesthetic drugs. This study was designed to compare propofol consumption and recovery characteristics in four ethnic groups: Chinese, Malays, and Indians in Malaysia and Caucasians in Italy. Patients undergoing total intravenous anaesthesia with propofol and fentanyl were evaluated for propofol consumption and recovery time. The Bispectral Index (BIS) was used to maintain the same anaesthesia depth in all patients. The BIS value, the response to verbal stimuli and eye-opening time were used to assess recovery. After propofol discontinuation the BIS values returned to baseline in 11±4.2 min for Caucasians, in 12.5±5.1 min for Chinese, 15.9±6.3 min for Malays and 22.1±8.1 for Indians. Time to eye-opening was 11.63±4.2 min in Caucasians, 13.23±4.9 min in Chinese, 16.97±5.2 min in Malays and 22.3±6.6 min in Indians. The propofol consumption was significantly lower in Indians compared to the other three groups (P<0.01). The recovery of Indians was much slower compared to Chinese, Malays and Caucasians. The recovery time of Malays is significantly slower compared to Chinese and Caucasians. Differences in propofol consumption and recovery time were not significant between Chinese and Caucasians, but the ratio recovery time/propofol consumption was significantly lower in Caucasians compared to all the other groups.
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Affiliation(s)
- O Ortolani
- University of Florence, Dipartimento di Area Critica Medico Chirurgica, Sezione di Anestesia e Rianimazione, Unita 'Anestesia e Rianimazione Sperimentali, University of Naples "Federico II", Naples, Italy
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Chan YK, Wong WY. [Robotic head and neck surgery at the Chinese University of Hong Kong]. Lin Chung Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2018; 32:1056-1060. [PMID: 30550146 DOI: 10.13201/j.issn.1001-1781.2018.14.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Indexed: 11/12/2022]
Abstract
Introduction:Robotic surgery in the head and neck region has been used to approach many different areas within the head and neck region. Here we describe our experiences of its application at The Chinese University of Hong Kong.Methods:This is a retrospective review of all cases operated by the two authors since Jan 2015 at the Department of Otorhinolaryngology, Head and Neck Surgery, The Chinese University of Hong Kong.Results:Twenty-four cases were performed with the da Vinci S or da Vinci Xi systems. Twenty-one cases were performed with the novel flexible robotic da Vinci SP system. There were no serious adverse events requiring a return to the operating room. Early results from the da Vinci SP have been previously published in seven patients that demonstrated the ability to reach the nasopharynx, oropharynx, hypopharynx, larynx and also retropharyngeal lymph nodes. There were no conversions to alternative surgical approaches. There were no serious adverse events or adverse events related to the use of this system.Discussion:In conclusion, through our experiences at The Chinese University of Hong Kong we have found the da Vinci robotic systems to be useful and safe in performing TORS and addressing pathologies in the neck through the retroauricular approach.
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Affiliation(s)
- Y K Chan
- Department of Otorhinolaryngology, Head and Neck Surgery,The Chinese University of Hong Kong
| | - W Y Wong
- Department of Otorhinolaryngology, Head and Neck Surgery,The Chinese University of Hong Kong
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8
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Scuffham PA, Ball J, Horowitz JD, Wong C, Newton PJ, Macdonald P, McVeigh J, Rischbieth A, Emanuele N, Carrington MJ, Reid CM, Chan YK, Stewart S. Standard vs. intensified management of heart failure to reduce healthcare costs: results of a multicentre, randomized controlled trial. Eur Heart J 2018; 38:2340-2348. [PMID: 28531281 PMCID: PMC5843128 DOI: 10.1093/eurheartj/ehx259] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 04/27/2017] [Indexed: 12/28/2022] Open
Abstract
Aims To determine if an intensified form of heart failure management programme (INT-HF-MP) based on individual profiling is superior to standard management (SM) in reducing health care costs during 12-month follow-up (primary endpoint). Methods and results A multicentre randomized trial involving 787 patients (full analysis set) discharged from four tertiary hospitals with chronic HF who were randomized to SM (n = 391) or INT-HF-MP (n = 396). Mean age was 74 ± 12 years, 65% had HF with a reduced ejection fraction (31.4 ± 8.9%) and 14% were remote-dwelling. Study groups were well matched. According to Green, Amber, Red Delineation of rIsk And Need in HF (GARDIAN-HF) profiling, regardless of location, patients in the INT-HF-MP received a combination of face-to-face (home visits) and structured telephone support (STS); only 9% (`low risk') were designated to receive the same level of management as the SM group. The median cost in 2017 Australian dollars (A$1 equivalent to ∼EUR €0.7) of applying INT-HF-MP was significantly greater than SM ($152 vs. $121 per patient per month; P < 0.001), However, at 12 months, there was no difference in total health care costs for the INT-HF-MP vs. SM group (median $1579, IQR $644 to $3717 vs. $1450, IQR $564 to $3615 per patient per month, respectively). This reflected minimal differences in all-cause mortality (17.7% vs. 18.4%; P = 0.848) and recurrent hospital stay (18.6 ± 26.5 vs. 16.6 ± 24.8 days; P = 0.199) between the INT-HF-MP and SM groups, respectively. Conclusion During 12-months follow-up, an INT-HF-MP did not reduce healthcare costs or improve health outcomes relative to SM.
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Affiliation(s)
- P A Scuffham
- Centre for Applied Health Economics, Menzies Health Institute Queensland, Griffith University, N78_2.42 The Circuit, Nathan, Queensland 4111, Australia
| | - J Ball
- Pre-Clinical Disease and Prevention, Baker Heart and Diabetes Institute, 75 Commercial Rd, Melbourne, Victoria 3004, Australia
| | - J D Horowitz
- Department of Cardiology, Queen Elizabeth Hospital, University of Adelaide, North Terrace, Adelaide, South Australia 5000, Australia
| | - C Wong
- Department of Cardiology, Western Health (Footscray Hospital), Melbourne Medical School, The University of Melbourne, Grattan St, Parkville, Victoria 3010, Australia
| | - P J Newton
- Centre for Cardiovascular and Chronic Care, Faculty of Health, University of Technology Sydney, 235 Jones St, Ultimo, New South Wales 2007, Australia
| | - P Macdonald
- Heart Failure and Transplant Unit, St Vincent's Hospital, 390 Victoria St, Darlinghurst, Sydney, NSW 2010, Australia
| | - J McVeigh
- Department of Cardiology, Prince of Wales Hospital, Barker St, Randwick, NSW 2031, Australia
| | - A Rischbieth
- National Heart Foundation of Australia, 500 Collins St Melbourne, Victoria 3000, Australia.,Faculty of Health Sciences, University of Adelaide, North Terrace, Adelaide, South Australia 5000, Australia
| | - N Emanuele
- National Heart Foundation of Australia, 500 Collins St Melbourne, Victoria 3000, Australia
| | - M J Carrington
- Pre-Clinical Disease and Prevention, Baker Heart and Diabetes Institute, 75 Commercial Rd, Melbourne, Victoria 3004, Australia.,Mary MacKillop Institute for Health Research, NHMRC of Australia Centre of Research Excellence to Reduce Inequality in Heart Disease, Australian Catholic University, Level 5, 215 Spring St, Melbourne, Victoria 3000, Australia
| | - C M Reid
- NHMRC Centre of Research Excellence in Cardiovascular Outcomes Improvement, Curtin University, Kent St, Bentley, Western Australia 6102, Australia
| | - Y K Chan
- Mary MacKillop Institute for Health Research, NHMRC of Australia Centre of Research Excellence to Reduce Inequality in Heart Disease, Australian Catholic University, Level 5, 215 Spring St, Melbourne, Victoria 3000, Australia
| | - S Stewart
- Mary MacKillop Institute for Health Research, NHMRC of Australia Centre of Research Excellence to Reduce Inequality in Heart Disease, Australian Catholic University, Level 5, 215 Spring St, Melbourne, Victoria 3000, Australia
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Wong D, Chan YK, Bek T, Wilson I, Stefánsson E. Intraocular currents, Bernoulli's principle and non-drainage scleral buckling for rhegmatogenous retinal detachment. Eye (Lond) 2018; 32:213-221. [PMID: 29350687 DOI: 10.1038/eye.2017.312] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 11/30/2017] [Indexed: 11/09/2022] Open
Abstract
For many years, it is not fully understood how non-drainage scleral buckling surgery brings about spontaneous reattachment of the detached retina when retinal breaks remain open at the end of surgery. Various explanations have been put forward, but none more interesting than the effect of fluid currents associated with eye movements. One such explanation involved the physics of the Bernoulli's principle. Daniel Bernoulli was an eighteenth century Swiss mathematician and he described an equation based on the conservation of energy. The sum of pressure energy, potential energy and kinetic energy remains constant. Bernoulli's equation usually applies to closed system such as the flow of fluid through pipes. When fluid flows through a constriction, the speed of fluid increases, the kinetic energy increases. If there was no change in elevation (potential energy), then the increase in kinetic energy must be accompanied by a decrease in pressure energy. In ophthalmic surgery, the Bernoulli's effect is the basis for venturi pumps that drive vitrectomy and phacoemulsification machines. This essay expounds on how Bernoulli's effect might be relevant to scleral buckling for retinal detachment repair. In the era when vitrectomy is increasing the primary surgical operation for retinal detachment, the pervasive advice is to emphasise the importance of patient adopting head posture and remaining still postoperatively. The exception is non-drainage scleral buckling surgery. Early postoperative mobilisation may be vital to achieve reattachment.
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Affiliation(s)
- D Wong
- Royal Liverpool University Hospital, Liverpool, UK
| | - Y K Chan
- Department of Mechanical Engineering, University of Hong Kong, Hong Kong SAR, China
| | - T Bek
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - I Wilson
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - E Stefánsson
- Landspitali University hospital, University of Iceland, Reykjavík, Iceland
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10
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Stefánsson E, Chan YK, Bek T, Hardarson SH, Wong D, Wilson DI. Laws of physics help explain capillary non-perfusion in diabetic retinopathy. Eye (Lond) 2018; 32:210-212. [PMID: 29350688 DOI: 10.1038/eye.2017.313] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 12/03/2017] [Indexed: 01/09/2023] Open
Abstract
The purpose is to use laws of physics to elucidate the mechanisms behind capillary non-perfusion in diabetic retinopathy. In diabetic retinopathy, loss of pericytes weakens capillary walls and the vessel dilates. A dilated capillary has reduced resistance to flow, therefore increased flow in that vessel and decreased in adjoining capillaries. A preferential shunt vessel is thus formed from the dilated capillary and the adjacent capillaries become non-perfused. We apply the laws of Laplace and Hagen-Poiseuille to better understand the phenomena that lead to capillary non-perfusion. These laws of physics can give a foundation for physical or mathematical models to further elucidate this field of study. The law of Laplace predicts that a weaker vessel wall will dilate, assuming constant transmural pressure. The Hagen-Poiseuille equation for flow and the Ostwald-de Waele relationship for viscosity predict that a dilated vessel will receive a higher portion of the fluid flow than the adjoining capillaries. Viscosity will decrease in the dilated vessel, furthering the imbalance and resulting in a patch of non-perfused capillaries next to the dilated 'preferential' shunt vessel. Physical principles support or inspire novel hypotheses to explain poorly understood phenomena in ophthalmology. This thesis of pericyte death and capillary remodelling, which was first proposed by Cogan and Kuwabara, already agrees with histological and angiographical observations in diabetic retinopathy. We have shown that it is also supported by classical laws of physics.
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Affiliation(s)
- E Stefánsson
- Landspitali University Hospital, University of Iceland, Reykjavík, Iceland
| | - Y K Chan
- Department of Mechanical Engineering, University of Hong Kong, Hong Kong SAR, China
| | - T Bek
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - S H Hardarson
- Institue of Physiology, University of Iceland, Reykjavik, Iceland
| | - D Wong
- Royal Liverpool University Hospital, Liverpool, UK
| | - D I Wilson
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
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Sung HK, Chan YK, Han M, Jahng JWS, Song E, Danielson E, Berger T, Mak TW, Sweeney G. Lipocalin-2 (NGAL) Attenuates Autophagy to Exacerbate Cardiac Apoptosis Induced by Myocardial Ischemia. J Cell Physiol 2017; 232:2125-2134. [PMID: 27800610 DOI: 10.1002/jcp.25672] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 10/17/2016] [Indexed: 12/19/2022]
Abstract
Lipocalin-2 (Lcn2; also termed neutrophil gelatinase-associated lipocalin (NGAL)) levels correlate positively with heart failure (HF) yet mechanisms via which Lcn2 contributes to the pathogenesis of HF remain unclear. In this study, we used coronary artery ligation surgery to induce ischemia in wild-type (wt) mice and this induced a significant increase in myocardial Lcn2. We then compared wt and Lcn2 knockout (KO) mice and observed that wt mice showed greater ischemia-induced caspase-3 activation and DNA damage measured by TUNEL than Lcn2KO mice. Analysis of autophagy by LC3 and p62 Western blotting, LC3 immunohistochemistry and transmission electron microscopy (TEM) indicated that Lcn2 KO mice had a greater ischemia-induced increase in autophagy. Lcn2KO were protected against ischemia-induced cardiac functional abnormalities measured by echocardiography. Upon treating a cardiomyocyte cell line (h9c2) with Lcn2 and examining AMPK and ULK1 phosphorylation, LC3 and p62 by Western blot as well as tandem fluorescent RFP/GFP-LC3 puncta by immunofluorescence, MagicRed assay for lysosomal cathepsin activity and TEM we demonstrated that Lcn2 suppressed autophagic flux. Lcn2 also exacerbated hypoxia-induced cytochromc c release from mitochondria and caspase-3 activation. We generated an autophagy-deficient H9c2 cell model by overexpressing dominant-negative Atg5 and found significantly increased apoptosis after Lcn2 treatment. In summary, our data indicate that Lcn2 can suppress the beneficial cardiac autophagic response to ischemia and that this contributes to enhanced ischemia-induced cell death and cardiac dysfunction. J. Cell. Physiol. 232: 2125-2134, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Hye Kyoung Sung
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Yee Kwan Chan
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Meng Han
- Department of Biology, York University, Toronto, Ontario, Canada
| | | | - Erfei Song
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Eric Danielson
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Thorsten Berger
- The Campbell Family Institute for Breast Cancer Research and Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada
| | - Tak W Mak
- The Campbell Family Institute for Breast Cancer Research and Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada
| | - Gary Sweeney
- Department of Biology, York University, Toronto, Ontario, Canada
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Chan YK, El-Nezami H, Chen Y, Kinnunen K, Kirjavainen PV. Probiotic mixture VSL#3 reduce high fat diet induced vascular inflammation and atherosclerosis in ApoE(-/-) mice. AMB Express 2016; 6:61. [PMID: 27576894 PMCID: PMC5005234 DOI: 10.1186/s13568-016-0229-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/12/2016] [Indexed: 02/07/2023] Open
Abstract
Atherosclerosis results from chronic inflammation potentially caused by translocation of bacterial components from the oro-gastrointestinal tract to circulation. Specific probiotics have anti-inflammatory effects and may reduce bacterial translocation. We thereby tested whether a probiotic mixture with documented anti-inflammatory potential could reduce atherosclerosis. ApoE−/− mice were fed high fat diet alone or with VSL#3 or a positive control treatment, telmisartan or both for 12 weeks. All treatments reduced atherosclerotic plaques significantly compared to high fat diet alone. VSL#3 significantly reduced proinflammatory adhesion molecules and risk factors of plaque rupture, reduced vascular inflammation and atherosclerosis to a comparable extent to telmisartan; and VSL#3 treated mice had the most distinctly different intestinal microbiota composition from the control groups. Combining the VSL#3 and telmisartan brought no further benefits. Our findings showed the therapeutic potential of VSL#3 in reducing atherosclerosis and vascular inflammation.
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Chan YK, Budgett SC, MacGibbon AK, Quek SY, Kindleysides S, Poppitt SD. Small particle size lipid emulsions, satiety and energy intake in lean men. Physiol Behav 2016; 169:98-105. [PMID: 27890592 DOI: 10.1016/j.physbeh.2016.11.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/26/2016] [Accepted: 11/19/2016] [Indexed: 01/17/2023]
Abstract
Lipid emulsions have been proposed to suppress hunger and food intake. Whilst there is no consensus on optimal structural properties or mechanism of action, small particle size (small-PS) stable emulsions may have greatest efficacy. Fabuless®, a commercial lipid emulsion reported in some studies to decrease energy intake (EI), is a small-PS, 'hard' fat emulsion comprising highly saturated palm oil base (PS, 82nm). To determine whether small-PS dairy lipid emulsions can enhance satiety, firstly, we investigated 2 'soft' fat dairy emulsions generated using dairy and soy emulsifying agents (PS, 114nm and 121nm) and a non-emulsified dairy control. Secondly, we investigated a small-PS palmolein based 'hard' fat emulsion (fractionated palm oil, PS, 104nm) and non-emulsified control. This was a 6 arm, randomized, cross-over study in 18 lean men, with test lipids delivered in a breakfast meal: (i) Fabuless® emulsion (FEM); (ii) dairy emulsion with dairy emulsifier (DEDE); (iii) dairy emulsion with soy lecithin emulsifier (DESE); (iv) dairy control (DCON); (v) palmolein emulsion with dairy emulsifier (PEDE); (vi) palmolein control (PCON). Participants rated postprandial appetite sensations using visual analogue scales (VAS), and ad libitum energy intake (EI) was measured at a lunch meal 3.5h later. Dairy lipid emulsions did not significantly alter satiety ratings or change EI relative to dairy control (DEDE, 4035kJ; DESE, 3904kJ; DCON, 3985kJ; P>0.05) nor did palm oil based emulsion relative to non-emulsified control (PEDE, 3902 kJ; PCON, 3973kJ; P>0.05). There was no evidence that small-PS dairy lipid emulsions or commercial Fabuless altered short-term appetite or food intake in lean adults.
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Affiliation(s)
- Y K Chan
- Human Nutrition Unit, University of Auckland, Auckland, New Zealand; School of Biological Sciences, University of Auckland, Auckland, New Zealand.
| | - S C Budgett
- Department of Statistics, University of Auckland, Auckland, New Zealand
| | - A K MacGibbon
- Fonterra Research and Development Centre, Palmerston North, New Zealand
| | - S Y Quek
- Department of Food Science, University of Auckland, Auckland, New Zealand
| | - S Kindleysides
- Human Nutrition Unit, University of Auckland, Auckland, New Zealand
| | - S D Poppitt
- Human Nutrition Unit, University of Auckland, Auckland, New Zealand; School of Biological Sciences, University of Auckland, Auckland, New Zealand; Department of Medicine, University of Auckland, Auckland, New Zealand.
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Chan YK, Brar MS, Kirjavainen PV, Chen Y, Peng J, Li D, Leung FCC, El-Nezami H. High fat diet induced atherosclerosis is accompanied with low colonic bacterial diversity and altered abundances that correlates with plaque size, plasma A-FABP and cholesterol: a pilot study of high fat diet and its intervention with Lactobacillus rhamnosus GG (LGG) or telmisartan in ApoE -/- mice. BMC Microbiol 2016; 16:264. [PMID: 27821063 PMCID: PMC5100306 DOI: 10.1186/s12866-016-0883-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 10/29/2016] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Atherosclerosis appears to have multifactorial causes - microbial component like lipopolysaccharides (LPS) and other pathogen associated molecular patterns may be plausible factors. The gut microbiota is an ample source of such stimulants, and its dependent metabolites and altered gut metagenome has been an established link to atherosclerosis. In this exploratory pilot study, we aimed to elucidate whether microbial intervention with probiotics L. rhamnosus GG (LGG) or pharmaceuticals telmisartan (TLM) could improve atherosclerosis in a gut microbiota associated manner. METHODS Atherosclerotic phenotype was established by 12 weeks feeding of high fat (HF) diet as opposed to normal chow diet (ND) in apolipoprotein E knockout (ApoE-/-) mice. LGG or TLM supplementation to HF diet was studied. RESULTS Both LGG and TLM significantly reduced atherosclerotic plaque size and improved various biomarkers including endotoxin to different extents. Colonial microbiota analysis revealed that TLM restored HF diet induced increase in Firmicutes/Bacteroidetes ratio and decrease in alpha diversity; and led to a more distinct microbial clustering closer to ND in PCoA plot. Eubacteria, Anaeroplasma, Roseburia, Oscillospira and Dehalobacteria appeared to be protective against atherosclerosis and showed significant negative correlation with atherosclerotic plaque size and plasma adipocyte - fatty acid binding protein (A-FABP) and cholesterol. CONCLUSION LGG and TLM improved atherosclerosis with TLM having a more distinct alteration in the colonic gut microbiota. Altered bacteria genera and reduced alpha diversity had significant correlations to atherosclerotic plaque size, plasma A-FABP and cholesterol. Future studies on such bacterial functional influence in lipid metabolism will be warranted.
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Affiliation(s)
- Yee Kwan Chan
- 5S12, Kadoorie Biological Sciences Building, School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong.
| | - Manreetpal Singh Brar
- 5N01, Kadoorie Biological Sciences Building, School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong.
| | - Pirkka V Kirjavainen
- Food and Research Health Centre, University of Eastern Finland, Joensuu, Finland
| | - Yan Chen
- L943, Laboratory Block, Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong
| | - Jiao Peng
- L943, Laboratory Block, Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong
| | - Daxu Li
- L943, Laboratory Block, Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong
| | - Frederick Chi-Ching Leung
- 5N01, Kadoorie Biological Sciences Building, School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong.,Bioinformatics Center, Nanjing Agricultural University, Nanjing, China
| | - Hani El-Nezami
- 5S12, Kadoorie Biological Sciences Building, School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong. .,Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland. .,5S13, Kadoorie Biological Sciences Building, The University of Hong Kong, Pokfulam, Hong Kong.
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15
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Chan YK, Sung HK, Jahng JWS, Kim GHE, Han M, Sweeney G. Lipocalin-2 inhibits autophagy and induces insulin resistance in H9c2 cells. Mol Cell Endocrinol 2016; 430:68-76. [PMID: 27090568 DOI: 10.1016/j.mce.2016.04.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/05/2016] [Accepted: 04/13/2016] [Indexed: 01/08/2023]
Abstract
Lipocalin-2 (Lcn2; also known as neutrophil gelatinase associated lipocalin, NGAL) levels are increased in obesity and diabetes and associate with insulin resistance. Correlations exist between Lcn2 levels and various forms or stages of heart failure. Insulin resistance and autophagy both play well-established roles in cardiomyopathy. However, little is known about the impact of Lcn2 on insulin signaling in cardiomyocytes. In this study, we treated H9c2 cells with recombinant Lcn2 for 1 h followed by dose- and time-dependent insulin treatment and found that Lcn2 attenuated insulin signaling assessed via phosphorylation of Akt and p70S6K. We used multiple assays to demonstrate that Lcn2 reduced autophagic flux. First, Lcn2 reduced pULK1 S555, increased pULK1 S757 and reduced LC3-II levels determined by Western blotting. We validated the use of DQ-BSA to assess autolysosomal protein degradation and this together with MagicRed cathepsin B assay indicated that Lcn2 reduced lysosomal degradative activity. Furthermore, we generated H9c2 cells stably expressing tandem fluorescent RFP/GFP-LC3 and this approach verified that Lcn2 decreased autophagic flux. We also created an autophagy-deficient H9c2 cell model by overexpressing a dominant-negative Atg5 mutant and found that reduced autophagy levels also induced insulin resistance. Adding rapamycin after Lcn2 could stimulate autophagy and recover insulin sensitivity. In conclusion, our study indicated that acute Lcn2 treatment caused insulin resistance and use of gain and loss of function approaches elucidated a causative link between autophagy inhibition and regulation of insulin sensitivity by Lcn2.
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Affiliation(s)
- Yee Kwan Chan
- Department of Biology, York University, Toronto, ON, M3J 1P3, Canada
| | - Hye Kyoung Sung
- Department of Biology, York University, Toronto, ON, M3J 1P3, Canada
| | | | - Grace Ha Eun Kim
- Department of Biology, York University, Toronto, ON, M3J 1P3, Canada
| | - Meng Han
- Department of Biology, York University, Toronto, ON, M3J 1P3, Canada
| | - Gary Sweeney
- Department of Biology, York University, Toronto, ON, M3J 1P3, Canada.
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16
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DeCoffe D, Quin C, Gill SK, Tasnim N, Brown K, Godovannyi A, Dai C, Abulizi N, Chan YK, Ghosh S, Gibson DL. Dietary Lipid Type, Rather Than Total Number of Calories, Alters Outcomes of Enteric Infection in Mice. J Infect Dis 2016; 213:1846-56. [PMID: 27067195 DOI: 10.1093/infdis/jiw084] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 02/18/2016] [Indexed: 12/19/2022] Open
Abstract
Dietary lipids modulate immunity, yet the means by which specific fatty acids affect infectious disease susceptibility remains unclear. Deciphering lipid-induced immunity is critical to understanding the balance required for protecting against pathogens while avoiding chronic inflammatory diseases. To understand how specific lipids alter susceptibility to enteric infection, we fed mice isocaloric, high-fat diets composed of corn oil (rich in n-6 polyunsaturated fatty acids [n-6 PUFAs]), olive oil (rich in monounsaturated fatty acids), or milk fat (rich in saturated fatty acids) with or without fish oil (rich in n-3 PUFAs). After 5 weeks of dietary intervention, mice were challenged with Citrobacter rodentium, and pathological responses were assessed. Olive oil diets resulted in little colonic pathology associated with intestinal alkaline phosphatase, a mucosal defense factor that detoxifies lipopolysaccharide. In contrast, while both corn oil and milk fat diets resulted in inflammation-induced colonic damage, only milk fat induced compensatory protective responses, including short chain fatty acid production. Fish oil combined with milk fat, unlike unsaturated lipid diets, had a protective effect associated with intestinal alkaline phosphatase activity. Overall, these results reveal that dietary lipid type, independent of the total number of calories associated with the dietary lipid, influences the susceptibility to enteric damage and the benefits of fish oil during infection.
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Affiliation(s)
- Daniella DeCoffe
- Department of Biology, University of British Columbia, Kelowna, Canada
| | - Candice Quin
- Department of Biology, University of British Columbia, Kelowna, Canada
| | - Sandeep K Gill
- Department of Biology, University of British Columbia, Kelowna, Canada
| | - Nishat Tasnim
- Department of Biology, University of British Columbia, Kelowna, Canada
| | - Kirsty Brown
- Department of Biology, University of British Columbia, Kelowna, Canada
| | - Artem Godovannyi
- Department of Biology, University of British Columbia, Kelowna, Canada
| | - Chuanbin Dai
- Department of Biology, University of British Columbia, Kelowna, Canada
| | - Nijiati Abulizi
- Department of Biology, University of British Columbia, Kelowna, Canada
| | - Yee Kwan Chan
- Department of Biology, University of British Columbia, Kelowna, Canada
| | - Sanjoy Ghosh
- Department of Biology, University of British Columbia, Kelowna, Canada
| | - Deanna L Gibson
- Department of Biology, University of British Columbia, Kelowna, Canada
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Affiliation(s)
- M Y Cheung
- Department of Orthopaedics and Traumatology, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong
| | - C L Lai
- Department of Orthopaedics and Traumatology, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong
| | - Wilson H Y Lam
- Department of Orthopaedics and Traumatology, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong
| | - James S K Lau
- Department of Orthopaedics and Traumatology, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong
| | - Aaron K H Lee
- Department of Orthopaedics and Traumatology, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong
| | - G G Yuen
- Department of Orthopaedics and Traumatology, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong
| | - Y K Chan
- Department of Orthopaedics and Traumatology, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong
| | - W L Tsang
- Department of Orthopaedics and Traumatology, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong
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18
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Shrestha S, Chan YK, Razali FN. Anesthetic Management for a Parturient with Facioscapulohumeral Muscular Dystrophy Undergoing Caesarean Section. Nepal j obstet gynaecol 2016. [DOI: 10.3126/njog.v10i2.14339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant muscle disorder characterized by progressive weakness and wasting of facial, shoulder girdle and upper arm muscles. Anesthetic management for the parturient with muscular dystrophy is very challenging for anesthesiologists because general as well as regional anesthesia may cause deleterious effect to the patient. We report a case of 28 years parturient with Facioscapulohumeral muscular dystrophy that underwent elective caesarean section under combined spinal epidural anesthesia. Intraoperative and postoperative period were uneventful however the motor block was prolonged. Regional anesthesia especially combined spinal epidural anesthesia can be safely used to provide anesthesia for caesarean section in patients with muscular dystrophy.
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19
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Jorstad HT, Chan YK, Scholte op Reimer WJM, Doornenbal J, Tijssen JGP, Peters RJG. Nurses' perspectives on nurse-coordinated prevention programmes in secondary prevention of cardiovascular disease: a pilot survey. Contemp Nurse 2015; 51:96-106. [PMID: 26572788 PMCID: PMC4784499 DOI: 10.1080/10376178.2015.1119032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Background: Secondary prevention of coronary artery disease (CAD) is increasingly provided by nurse-coordinated prevention programs (NCPP). Little is known about nurses’ perspectives on these programs. Aim: To investigate nurses’ perspectives/experiences in NCPPs in acute coronary syndrome patients. Methods: Thirteen nurses from NCPPs in 11 medical centers in the RESPONSE trial completed an online survey containing 45 items evaluating 3 outcome categories: (1) conducting NCPP visits; (2) effects of NCPP interventions on risk profiles and (3) process of care. Results: Nurses felt confident in counseling/motivating patients to reduce CAD risk. Interventions targeting LDL, blood pressure and medication adherence were reported as successful, corresponding with significant improvements of these risk factors. Improving weight, smoking and physical activity was reported as less effective. Screening for anxiety/depression was suggested as an improvement. Conclusions: Nurses acknowledge the importance and effectiveness of NCPPs, and correctly identify which components of the program are the most successful. Our study provides a basis for implementation and quality improvement for NCCPs.
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Affiliation(s)
- H T Jorstad
- a Department of Cardiology , Academic Medical Center - University of Amsterdam , Meibergdreef 9, 1100 DE Amsterdam , The Netherlands
| | - Y K Chan
- a Department of Cardiology , Academic Medical Center - University of Amsterdam , Meibergdreef 9, 1100 DE Amsterdam , The Netherlands
| | - W J M Scholte op Reimer
- b Amsterdam University of Applied Sciences , Nicolaes Tulphuis, Tafelbergweg 51, 1105 BD Amsterdam , The Netherlands
| | - J Doornenbal
- a Department of Cardiology , Academic Medical Center - University of Amsterdam , Meibergdreef 9, 1100 DE Amsterdam , The Netherlands
| | - J G P Tijssen
- a Department of Cardiology , Academic Medical Center - University of Amsterdam , Meibergdreef 9, 1100 DE Amsterdam , The Netherlands
| | - R J G Peters
- a Department of Cardiology , Academic Medical Center - University of Amsterdam , Meibergdreef 9, 1100 DE Amsterdam , The Netherlands
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20
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Park M, Sabetski A, Kwan Chan Y, Turdi S, Sweeney G. Palmitate induces ER stress and autophagy in H9c2 cells: implications for apoptosis and adiponectin resistance. J Cell Physiol 2015; 230:630-9. [PMID: 25164368 DOI: 10.1002/jcp.24781] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 08/22/2014] [Indexed: 02/06/2023]
Abstract
The association between obesity and heart failure is well documented and recent studies have indicated that understanding the physiological role of autophagy will be of great significance. Cardiomyocyte apoptosis is one component of cardiac remodeling which leads to heart failure and in this study we used palmitate-treated H9c2 cells as an in vitro model of lipotoxicity to investigate the role of autophagy in cell death. Temporal analysis revealed that palmitate (100 μM) treatment induced a gradual increase of intracellular lipid accumulation as well as apoptotic cell death. Palmitate induced autophagic flux, determined via increased LC3-II formation and p62 degradation as well as by detecting reduced colocalization of GFP with RFP in cells overexpressing tandem fluorescent GFP/RFP-LC3. The increased level of autophagy indicated by these measures were confirmed using transmission electron microscopy (TEM). Upon inhibiting autophagy using bafilomycin we observed an increased level of palmitate-induced cell death assessed by Annexin V/PI staining, detection of active caspase-3 and MTT cell viability assay. Interestingly, using TEM and p-PERK or p-eIF2α detection we observed increased endoplasmic reticulum (ER) stress in response to palmitate. Autophagy was induced as an adaptive response against ER stress since it was sensitive to ER stress inhibition. Palmitate-induced ER stress also induced adiponectin resistance, assessed via AMPK phosphorylation, via reducing APPL1 expression. This effect was independent of palmitate-induced autophagy. In summary, our data indicate that palmitate induces autophagy subsequent to ER stress and that this confers a prosurvival effect against lipotoxicity-induced cell death. Palmitate-induced ER stress also led to adiponecin resistance.
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Affiliation(s)
- Min Park
- Department of Biology, York University, Toronto, Canada
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21
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Abstract
A macrocephalic girl presented with generalised epilepsy due to focal cortical dysplasia. She later developed multiple hamartomatous lesions and was diagnosed to have Cowden syndrome. The diagnosis was confirmed by identification of a novel frameshift mutation in the PTEN gene of the patient.
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Affiliation(s)
- K M Cheung
- Department of Paediatrics, Caritas Medical Centre, Shamshuipo, Hong Kong
| | - C W Lam
- Department of Pathology, The University of Hong Kong, Pokfulam, Hong Kong
| | - Y K Chan
- Department of Medicine and Geriatrics, Caritas Medical Centre, Shamshuipo, Hong Kong
| | - W K Siu
- Kowloon West Cluster Laboratory Genetic Service, Chemical Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Laichikok, Hong Kong
| | - L Yong
- Department of Surgery, Caritas Medical Centre, Shamshuipo, Hong Kong
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22
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Vaithilingam RD, Safii SH, Baharuddin NA, Karen-Ng LP, Saub R, Ariffin F, Ramli H, Sharifuddin A, Hidayat MFH, Raman R, Chan YK, Rani NA, Rahim RA, Shahruddin N, Cheong SC, Bartold PM, Zain RB. Establishing and managing a periodontal biobank for research: the sharing of experience. Oral Dis 2014; 21:e62-9. [PMID: 24930489 DOI: 10.1111/odi.12267] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 05/12/2014] [Accepted: 06/08/2014] [Indexed: 12/30/2022]
Abstract
Periodontal bio-repositories, which allow banking of clinically validated human data and biological samples, provide an opportunity to derive biomarkers for periodontal diagnosis, prognosis and therapeutic activities which are expected to improve patient management. This article presents the establishing of the Malaysian Periodontal Database and Biobank System (MPDBS) which was initiated in 2011 with the aim to facilitate periodontal research. Partnerships were established with collaborating centres. Policies on specimen access, authorship and acknowledgement policies were agreed upon by all participating centres before the initiation of the periodontal biobank. Ethical approval for the collection of samples and data were obtained from institutional ethics review boards. A broad-based approach for informed consent was used, which covered areas related to quality of life impacts, genetics and molecular aspects of periodontal disease. Sample collection and processing was performed using a standardized protocol. Biobanking resources such as equipment and freezers were shared with the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS). In the development of the MPDBS, challenges that were previously faced by the MOCDTBS were considered. Future challenges in terms of ethical and legal issues will be faced when international collaborations necessitate the transportation of specimens across borders.
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Affiliation(s)
- R D Vaithilingam
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
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23
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Shariffuddin II, Rai V, Chan YK, Muniandy RK. Safe delivery of two parturient women in severe metabolic acidosis. BMJ Case Rep 2014; 2014:bcr-2014-205135. [PMID: 24862427 DOI: 10.1136/bcr-2014-205135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Care of an acutely ill parturient is particularly difficult when we have to balance the needs of both mother and the fetus to survive. The literature suggests there should be emphasis on stabilising the mother's condition. In dealing with metabolic acidosis, however, we believe delivering the baby early might not only relieve the threat of the acidosis on the mother, it may be the only way to deliver a live baby. We report two parturient women with severe metabolic acidosis which was considerably reduced very soon after the delivery and how our timely delivery resulted in the birth of two neurologically intact babies.
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Affiliation(s)
| | - Vineya Rai
- Department of Anaesthesiology, University of Malaya, Kuala Lumpur, Wilayah Persekutuan, Malaysia
| | - Y K Chan
- Department of Anaesthesiology, University of Malaya, Kuala Lumpur, Wilayah Persekutuan, Malaysia
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Abstract
Various disease states are associated with an imbalance of protective and pathogenic bacteria in the gut, termed dysbiosis. Current evidence reveals that dietary factors affect the microbial ecosystem in the gut. Changes to community structure of the intestinal microbiota are not without consequence considering the wide effects that the microbes have on both local and systemic immunity. The goal of this review is to give insight into the importance of gut microbiota in disease development and the possible therapeutic interventions in clinical settings. We introduce the complex tripartite relationship between diet, microbes and the gut epithelium. This is followed by a summary of clinical evidence of diet-induced dysbiosis as a contributing factor in the development of gastrointestinal diseases like inflammatory bowel disease, irritable bowel syndrome and colorectal cancer, as well as systemic diseases like obesity, diabetes, atherosclerosis and nonalcoholic fatty liver disease. Finally, the current dietary and microbial interventions to promote a healthy microbial profile will be reviewed.
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Affiliation(s)
- Yee Kwan Chan
- Department of Biology, University of British Columbia Okanagan, Kelowna, B.C., Canada
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25
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Hussain Khan Z, Chan YK. SAPS II, SAPS III versus markers of tissue oxygen delivery: discerning their role in predicting outcome for cardiopulmonary arrest. Minerva Anestesiol 2012; 78:1313-1315. [PMID: 23222997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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26
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Li D, Tsang JYS, Peng J, Ho DHH, Chan YK, Zhu J, Lui VCH, Xu A, Lamb JR, Tam PKH, Chen Y. Adiponectin mediated MHC class II mismatched cardiac graft rejection in mice is IL-4 dependent. PLoS One 2012; 7:e48893. [PMID: 23155424 PMCID: PMC3498365 DOI: 10.1371/journal.pone.0048893] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 10/03/2012] [Indexed: 11/18/2022] Open
Abstract
Background Adiponectin regulates glucose and fatty-acid metabolism but its role in chronic graft rejection mediated by Th2 cytokines remains ill-defined. Methodology/Principal Findings Wild type and adiponectin-null mice were used as graft recipients in mouse MHC class II disparate cardiac transplantation (bm12 toB6) and the graft rejection was monitored. In adiponectin-null mice we observed that the cellular infiltrate of eosinophils, CD4+ and CD8+ T cells was reduced in grafts compared to the controls as was collagen deposition and vessel occlusion. A similar outcome was observed for skin transplants except that neutrophil infiltration was increased. Low levels of IL-4 were detected in the grafts and serum. The effect of adiponectin signaling on IL-4 expression was further investigated. Treatment with AMPK and p38 MAPK inhibitors blocked adiponectin enhanced T cell proliferation in mixed lymphocyte reactions. Inhibition of AMPK reduced eosinophil infiltration in skin grafts in wild type recipients and in contrast AMPK activation increased eosinophils in adiponectin-null recipients. The addition of adiponectin increased IL-4 production by the T cell line EL4 with augmented nuclear GATA-3 and phospho-STAT6 expression which were suppressed by knockdown of adiponectin receptor 1 and 2. Conclusions Our results demonstrate a direct effect of adiponectin on IL-4 expression which contributes to Th2 cytokine mediated rejection in mouse MHC class II histoincompatible transplants. These results add to our understanding of the interrelationship of metabolism and immune regulation and raise the possibility that AMPK inhibitors may be beneficial in selected types of rejection.
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Affiliation(s)
- Daxu Li
- Paediatric Surgery Division, Department of Surgery, The University of Hong Kong, Hong Kong SAR, China
| | - Julia Y. S. Tsang
- Paediatric Surgery Division, Department of Surgery, The University of Hong Kong, Hong Kong SAR, China
| | - Jiao Peng
- Paediatric Surgery Division, Department of Surgery, The University of Hong Kong, Hong Kong SAR, China
| | - Derek H. H. Ho
- Department of Chemistry, The University of Hong Kong, Hong Kong SAR, China
| | - Yee Kwan Chan
- School of Biological Science, The University of Hong Kong, Hong Kong SAR, China
| | - Jiang Zhu
- Paediatric Surgery Division, Department of Surgery, The University of Hong Kong, Hong Kong SAR, China
| | - Vincent C. H. Lui
- Paediatric Surgery Division, Department of Surgery, The University of Hong Kong, Hong Kong SAR, China
| | - Aimin Xu
- Department of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Jonathan R. Lamb
- Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, London, United Kingdom
| | - Paul K. H. Tam
- Paediatric Surgery Division, Department of Surgery, The University of Hong Kong, Hong Kong SAR, China
- * E-mail: (YC); (PT)
| | - Yan Chen
- Paediatric Surgery Division, Department of Surgery, The University of Hong Kong, Hong Kong SAR, China
- Department of Chemistry, The University of Hong Kong, Hong Kong SAR, China
- * E-mail: (YC); (PT)
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Bishop FL, Rea A, Lewith H, Chan YK, Saville J, Prescott P, Elm EV, Lewith GT. Complementary medicine use by men with prostate cancer: a systematic review of prevalence studies. Prostate Cancer Prostatic Dis 2010; 14:1-13. [DOI: 10.1038/pcan.2010.38] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Sivarani S, Chan YK, Liam CK, Kumar G, Abdullah BJ, Mahadeva S. Education and Imaging. Gastrointestinal: massive intraperitoneal haemorrhage in a young woman with hereditary hemorrhagic telangiectasia. J Gastroenterol Hepatol 2010; 25:1587. [PMID: 20796159 DOI: 10.1111/j.1440-1746.2010.06469.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Affiliation(s)
- S Sivarani
- Department of Medicine, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
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Cheung KM, Yeung YW, Chan YK, Ko CH. Comparison of oesophagogastroduodenoscopy findings and diagnostic value in neurologically impaired children and 'normal' children. Hong Kong Med J 2008; 14:465-468. [PMID: 19060346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
OBJECTIVES To review the oesophagogastroduodenoscopy findings in children with severe neurological impairment and 'normal' children, over a 7-year period from 2000 to 2007. DESIGN Retrospective study. SETTING Paediatric Unit of Caritas Medical Centre, Hong Kong. MAIN OUTCOME MEASURES The frequencies of Helicobacter pylori status, peptic ulceration, and oesophagitis were compared. The diagnostic value of oesophagogastroduodenoscopy in these two groups of children was also examined. PATIENTS Patient data were retrieved from the Hospital Authority Clinical Management system, excluding those under surgical care. The children were divided into two groups: 'normal' and neurologically impaired. Their demographic data, indications for oesophagogastroduodenoscopy, endoscopy diagnoses, and Helicobacter pylori status were compared, as was the diagnostic value of oesophagogastroduodenoscopy. RESULTS From 2000 to 2007, 223 oesophagogastroduodenoscopies were performed in 176 patients aged 3 to 22 years; 134 were performed in 'normal' children (median age, 14; range, 3-22 years) and 89 in neurologically impaired children (median age, 12; range, 3-20 years). The three most common indications in 'normal' children were: epigastric pain (60%), gastro-intestinal bleeding (13%), and vomiting (7%). In neurologically impaired children, they were gastro-intestinal bleeding (51%), assessment for percutaneous endoscopic gastrostomy (27%), and follow-up for previous lesions (9%). Among 'normal' children, 14 had duodenal ulcers (associated with Helicobacter pylori in 13), but no patients had gastric ulcers or oesophagitis. Among neurologically impaired children, one had a Helicobacter pylori-negative duodenal ulcer, and four had gastric ulcers (three were Helicobacter pylori-positive). Twenty-four neurologically impaired children had oesophagitis. Neurologically impaired children had significantly more oesophagitis and gastric ulcers (P<0.001 and P=0.004, respectively) but less duodenal ulcers (P=0.024). In 111 children who had gastric biopsies, the Helicobacter pylori infection rate was 35% (31% in 'normal' children and 43% in the neurologically impaired). The diagnostic value was 37% in 'normal' children and 81% in the neurologically impaired (P<0.001). The overall diagnostic value of oesophagogastroduodenoscopy was 50%. CONCLUSION The clinical presentation and endoscopic findings in 'normal' and neurologically impaired children were discrepant. Oesophagogastroduodenoscopy appeared to confer greater diagnostic value in neurologically impaired than 'normal' children. Diagnostic values in our unit were comparable to reports from western studies.
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Affiliation(s)
- K M Cheung
- Department of Paediatrics, Caritas Medical Centre, Shamshuipo, Kowloon, Hong Kong.
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Mak SS, Yuen ML, Li C, Chan YK, Mo KF, Lee KM, Chan SJ. Exploratory Analysis of the Bacteriological Status of Post-irradiation Wounds and Its Relationship to Healing. Clin Oncol (R Coll Radiol) 2006; 18:519-24. [PMID: 16969981 DOI: 10.1016/j.clon.2006.04.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
AIMS To investigate the bacteriological status of post-irradiation wounds and its relationship to wound healing in patients with nasopharyngeal cancer. MATERIALS AND METHODS One hundred and forty-six nasopharyngeal cancer patients with post-irradiation wounds on one or both sides of the neck were studied prospectively. Swabs were taken from the wounds at the initial study visit for bacteriological examination. A further swab for culture was taken when possible signs of infection developed. Wound healing was assessed on alternate days with respect to wound condition, the presence of clinical infection and healing time. RESULTS The results showed that most of the post-irradiation wounds were colonised with bacteria. This was not associated with clinical signs of infection in any instance. There was no association between wound healing time and the presence of organisms, the identity of organisms, the number of species of organisms, or the use of antibiotics. CONCLUSIONS The presence of bacteria in post-irradiation wounds, in the absence of clinical signs of wound infection, is not a barrier to wound healing. Oncology practitioners should recognise the unique features of radiation-induced wounds and skin reactions with confidence and provide appropriate treatment as needed.
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Affiliation(s)
- S S Mak
- Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong, China.
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Chuah KH, Mansor M, Rajen G, Wang CY, Chan YK. Technique of anaesthesia in pulmonary hypertension and thrombophilia in early pregnancy. Med J Malaysia 2006; 61:114-6. [PMID: 16708749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Pulmonary hypertension in pregnancy is a rare condition but is associated with a high mortality. We report the case of a 29 year old female in early pregnancy with Protein C and S deficiency with recurrent deep venous thrombosis and pulmonary embolism and subsequent secondary pulmonary hypertension. The patient was counselled and consented for termination of pregnancy with tubal sterilization. She was administered continuous spinal anaesthesia with invasive monitoring. The successful anaesthetic management of this condition is described.
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Affiliation(s)
- K H Chuah
- Department of Anaesthesiology, University Malaya Medical Centre, Lembah Pantai, Kuala Lumpur 59100, Kuala Lumpur
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Lo WYF, Li JYW, Chan YK, Lai LSW, Yeung YW, Lo STH, Tsui WMS, Ng CS. Instability of clonality in gastric lymphoid infiltrates: a study with emphasis on serial biopsies. Am J Surg Pathol 2006; 29:1582-92. [PMID: 16327430 DOI: 10.1097/01.pas.0000188031.40836.00] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The evolution of low-grade B-cell mucosa-associated lymphoid-tissue (MALT) lymphoma of the stomach is a multistage process, reflected in the histologic continuum from Helicobacter pylori-chronic gastritis, to low-grade and high-grade lymphoma. Interestingly, in daily gastric biopsy sign-out, the authors observed that some biopsies showed monoclonality on polymerase chain reaction (PCR) even though there were no definite histologic features of malignancy and vice versa. To address the question, the authors studied the endoscopic gastric biopsies at first presentation of 46 patients to examine any clonality differences among various histologic patterns within the spectrum of MALT lymphoma evolution. The gastric biopsies were reviewed histologically and graded according to the Wotherspoon-Isaacson histologic scoring system from grade 0 (normal) to grade 5 (MALT lymphoma). The clonality of cases in each grade was determined by performing nested PCR for immunoglobulin heavy chain (IgH) gene rearrangement using FR2/JH and FR3/JH primer sets. The monoclonality rates among different grades were as follows: grade 2, 6.3% (1 of 16); grade 3, 27.3% (3 of 11); grade 4, 83.3% (5 of 6); grade 5, 69.2% (9 of 13). Statistically significant difference of monoclonality rate is demonstrated in histologic grade 4 versus grades 2 and 3, and grade 5 versus grade 2 (P < 0.05, Fisher exact test). The authors went on to examine the progress of disease by following up the clinical status, histologic changes, and clonality fluctuation of these cases. Four of the 8 patients with monoclonality on PCR, but no definite lymphoma at first presentation later progressed to frank MALT lymphoma. Our study shows that, during the progression to MALT lymphoma, there is an instability of clonality. Clonality can fluctuate between polyclonality, oligoclonality, and monoclonality, none of which defines an irreversible stage for progression to MALT lymphoma. Monoclonality is a risk factor for development of MALT lymphoma. Those cases with dense gastric mucosal lymphoid infiltrate (without definite MALT lymphoma) and monoclonality on PCR need to be closely monitored and Helicobacter infection promptly treated if present. In combination with clinicohistologic examination, PCR can serve as a complementary tool in arriving at a definite diagnosis of MALT lymphoma in cases with borderline histologic features.
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Affiliation(s)
- William Y F Lo
- Pathology Service, Caritas Medical Centre, Kowloon, Hong Kong, China.
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Poppitt SD, Leahy FE, Keogh GF, Wang Y, Mulvey TB, Stojkovic M, Chan YK, Choong YS, McArdle BH, Cooper GJS. Effect of high-fat meals and fatty acid saturation on postprandial levels of the hormones ghrelin and leptin in healthy men. Eur J Clin Nutr 2005; 60:77-84. [PMID: 16118648 DOI: 10.1038/sj.ejcn.1602270] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Ghrelin and leptin play a role in control of food intake and adiposity but mechanisms regulating these hormones in man are poorly defined and evidence that dietary fats may have adverse effects is inconclusive. We investigated whether high-fat meals, which differed in saturated fatty acid (SFA) content acutely modified these hormones. DESIGN Randomised, double-blind, crossover trial. A high-fat (HF) test meal (59 +/- 4 g fat; 71% of energy as fat) was given for breakfast on two occasions. Meals comprised either high (approximately 70:30) or low (approximately 55:45) saturated:unsaturated fatty acid (SFA:USFA) ratio. Fasting and postprandial measurements of serum total ghrelin (RIA), leptin (enzyme-linked immunosorbent assay (ELISA)) and insulin (RIA) were made over 6 h. Postprandial measurements were also made at 10 and 24 h following a fat-exclusion lunch, snack and dinner. SUBJECTS A total of 18 lean, healthy men. RESULTS There was no significant effect of the fatty meal (time, P > 0.05), nor a differential effect of SFA:USFA ratio (treatment*time, P > 0.05) on ghrelin over 6h. Leptin decreased in response to both HF treatments (time, P < 0.001) but increased SFA content did not further inhibit hormone secretion (treatment*time, P > 0.05). There was no significant correlation between ghrelin or leptin and circulating insulin (P>0.05). CONCLUSION We conclude that HF diets may adversely effect serum leptin, although the circadian decrease may account in part for this response. Increasing dietary SFAs had no deleterious effects on leptin or total ghrelin.
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Affiliation(s)
- S D Poppitt
- Human Nutrition & Metabolic Unit, University of Auckland, Auckland, New Zealand.
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Chan YK, Chiu KY, Cheng SW, Ho P. The incidence of deep vein thrombosis in elderly Chinese suffering hip fracture is low without prophylaxis: a prospective study using serial duplex ultrasound. J Orthop Surg (Hong Kong) 2004; 12:178-83. [PMID: 15621903 DOI: 10.1177/230949900401200208] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
PURPOSE To investigate the incidence of deep vein thrombosis (DVT) among elderly Hong Kong Chinese patients suffering from acute hip fracture and to analyse the risk factors associated with DVT. METHODS A total of 100 consecutive Chinese hip fracture patients with a mean age of 80 years were investigated serially using duplex ultrasound scans preoperatively and at 1 week, 3 to 6 weeks, and 3 months postoperatively. No chemoprophylaxis or prophylaxis against DVT was given. RESULTS 95 patients completed 3 duplex scans during hospitalisation; 5 (5.3%) of them were found to have developed DVT over the ilio-femoral venous segment. Of the 90 patients who had no DVT, 73 were reassessed 3 months after operation; one of them was found to have developed calf DVT. Older patients, chairbound or dependent patients, and patients living in institutions carried a higher risk of developing DVT. CONCLUSION This prospective study shows that the incidence of DVT developing after acute hip fracture in Chinese geriatric patients was low. We therefore do not recommend routine chemoprophylaxis for elderly patients with hip fracture.
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Affiliation(s)
- Y K Chan
- Department of Orthopaedic Surgery, Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong.
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Abstract
We describe a Chinese woman who developed severe heart failure 3 years from the onset of systemic lupus erythematosus (SLE). Endomyocardial biopsy confirmed lupus myocarditis, with focal infiltrates of small lymphocytes and some polymorphic neutrophils. The conventional treatment for cardiac failure plus oral prednisolone failed to bring clinical and echocardiographical improvement until the addition of intravenous (i.v.) 'pulse' cyclophosphamide. Three weeks after i.v. cyclophosphamide treatment, there was significant improvement of her heart failure symptoms with improvement in the ejection fraction from 19% to 63%.
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Affiliation(s)
- Y K Chan
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, PRC.
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Chan YK, Wong CK, Hsieh DPH, Ng SP, Lau TK, Wong PK. Application of a toxicity identification evaluation for a sample of effluent discharged from a dyeing factory in Hong Kong. Environ Toxicol 2003; 18:312-316. [PMID: 14502583 DOI: 10.1002/tox.10130] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A first toxicity identification evaluation (TIE) was conducted in three phases using the Microtox test to identify the major toxicant(s) in effluent discharged from a dyeing plant in Hong Kong. In Phase I toxicity characterization indicated that anions were likely to be the major toxicants for the entire effluent. In Phase II concentrations of sulfite and other anions in the original and the anion exchange resin-treated effluent samples were determined by ion chromatography. Anions, which were found in the effluent at comparatively high concentrations and were suspected of being responsible for the toxicity to luminescent bacteria, were selected for further study in Phase III. Investigation in Phase III using the spiking and mass balance approaches confirmed that the sulfite ion was the major toxicant in the effluent.
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Affiliation(s)
- Y K Chan
- Environmental Science Program, The Chinese University of Hong Kong, Shalin, N.T., Hong Kong, SAR, China
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Abstract
Mesangial lupus nephritis was thought to be a mild form of lupus nephritis. However, case reports suggest that this type of nephritis could be associated with a high rate of transformation to more serious classes. We retrospectively reviewed the clinical features, clinical response at one year following treatment, as well as the long-term outcome of patients with mesangial lupus nephritis identified on their first renal biopsy. The possible clinical parameters that may predict poor outcome were examined. Nineteen patients with a median duration of follow-up of 9.6 (2.5-11.4) years were identified. At one year after biopsy, eight patients achieved complete remission, two patients achieved partial remission and nine patients had no response. Of the 10 responders, four relapsed after a median duration of 53 (42-97) months. Nine out of 10 patients (six nonresponders and four responders who relapsed) who underwent a second biopsy showed transformation to a higher grade nephritis. The long-term outcome remained favourable in nine patients. Responders and patients who were given angiotensin-converting enzyme inhibitors were associated with favourable long-term outcome. Our data highlight that renal biopsy should be repeated early in Chinese patients with mesangial nephritis who failed to respond to treatment in order to identify those who may require intense immunosuppressive therapy.
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Affiliation(s)
- L S Tam
- Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong.
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Chan YK, Chiu KY, Yip DKH, Ng TP, Tang WM. Full weight bearing after non-cemented total hip replacement is compatible with satisfactory results. Int Orthop 2003; 27:94-7. [PMID: 12700932 PMCID: PMC3460654 DOI: 10.1007/s00264-002-0419-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/07/2002] [Indexed: 10/25/2022]
Abstract
Two matched groups of 29 patients underwent hydroxyapatite-coated non-cemented total hip replacement. One group was started on immediate protected-weight-bearing walking and the other group was started on immediate full-weight-bearing walking. They were followed up regularly for 2 years. They were assessed with Harris hip score clinically and Engh's criteria of osteo-integration radiographically. No difference was found between the two groups. All patients had excellent clinical outcome after hip replacement, and all femoral stems were stable radiographically. Patients can walk with full weight bearing safely immediate after hydroxyapatite-coated non-cemented total hip replacement.
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Affiliation(s)
- Y K Chan
- Department of Orthopaedics and Traumatology, Queen Mary Hospital, 5/F Professorial Block, Pokfulam, Hong Kong S.A.R., China.
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Chiu CL, Mansor M, Ng KP, Chan YK. Retrospective review of spinal versus epidural anaesthesia for caesarean section in preeclamptic patients. Int J Obstet Anesth 2003; 12:23-7. [PMID: 15676316 DOI: 10.1016/s0959-289x(02)00137-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/01/2002] [Indexed: 10/27/2022]
Abstract
A 5-year retrospective survey of anaesthesia for caesarean section for mild/moderate and severe preeclampsia was performed, covering the period between 1 January 1996 and 31 December 2000. One hundred and twenty-one cases of non-labouring preeclamptic patients receiving spinal or epidural anaesthesia for caesarean section were included for analysis. Comparisons were made of the lowest blood pressures recorded before induction of anaesthesia, during the period from induction to delivery and the period from delivery to the end of operation. The decreases in blood pressure were similar after spinal and epidural anaesthesia. The use of intravenous fluids and ephedrine were also comparable in the two anaesthetic groups. There was no difference in maternal or neonatal outcome. Our result supports the use of spinal anaesthesia in preeclamptic women.
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Affiliation(s)
- C L Chiu
- Department of Anaesthesia, University Malaya Medical Centre, Kuala Lumpur, Malaysia.
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Chan YK, Ng KP, Chiu CL. Trends in obstetric anaesthesia and analgesia over a ten year period in the University Malaya Medical Centre, Kuala Lumpur. Int J Obstet Anesth 2002; 11:176-9. [PMID: 15321544 DOI: 10.1054/ijoa.2002.0954] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Available data for obstetric care in the University Malaya Medical Centre, Kuala Lumpur from 1987 to 1999 were reviewed. Despite incomplete data, we were able to determine fairly well the practice of obstetric anaesthesia and analgesia in the unit, and the changes over the years. There was a decline in the use of general anaesthesia for both elective and emergency caesarean sections from 41.3% and 69.4% respectively in 1995 to 21.6% and 26.9% respectively in 1999. By 1999, regional anaesthesia had become the most common method of anaesthesia administered in both elective (14.3% epidural and 63.5% spinal) and emergency (30.2% epidural and 42.6% spinal) caesarean sections. The percentage of patients delivering vaginally who received epidural analgesia appeared to have stabilised at about 8 to 9% in the last few years, with a gradual decline in the total instrumental delivery rate from a high of about 12% to the pre-epidural rate of 7%.
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Affiliation(s)
- Y K Chan
- Department of Anaesthesia, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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Abstract
OBJECTIVE Central nervous system correlates of the visceral hyperalgesia documented in patients with irritable bowel syndrome are limited. Reproducible cerebral evoked potentials can be recorded in response to rhythmic balloon distension of the rectum in healthy adults. Irritable bowel syndrome patients and healthy subjects were studied to compare the characteristics of mechanically-evoked rectal cerebral potentials obtained during fasting and after the ingestion of a standard meal. METHODS Twenty-two pairs of age-matched healthy female subjects and female irritable bowel syndrome patients were studied. Cerebral evoked potentials were recorded in response to rhythmic rectal distension (two distension series each of 100 repetitions at 0.8 hertz); cerebral evoked potential recordings were repeated after a 1000 kcal (46% fat) liquid meal. Trait and state anxiety questionnaires were also completed. RESULTS Compared to healthy subjects, irritable bowel syndrome patients demonstrated higher prevalence of cerebral evoked potential early peaks (latency < 100 ms) postprandially, and uniformly shorter cerebral evoked potential latencies both before and after feeding. CONCLUSION These findings provide further objective evidence for defective visceral afferent transmission in irritable bowel syndrome patients.
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Affiliation(s)
- Y K Chan
- Department of Gastroenterology, Royal North Shore Hospital, University of Sydney, Australia
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Shen DH, Khoo US, Xue WC, Ngan HY, Wang JL, Liu VW, Chan YK, Cheung AN. Primary peritoneal malignant mixed Müllerian tumors. A clinicopathologic, immunohistochemical, and genetic study. Cancer 2001; 91:1052-60. [PMID: 11251959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
BACKGROUND Primary peritoneal malignant mixed Müllerian tumors (MMMTs) are rarely reported in the literature. METHODS The clinical, pathologic, and immunohistochemical features of five cases of MMMT of female peritoneum were analyzed. The tumors were also investigated for expression of hormone receptors, specific BRCA-1 mutations, and clonality. RESULTS The patients' ages ranged from 33 to 67 years. They presented with abdominal pain or mass. One case of peritoneal MMMT was associated with a synchronous endometrial carcinoma whereas another case was detected 2 years after the diagnosis of a primary adenocarcinoma of the fallopian tube. One patient died 1 month after diagnosis whereas 2 patients died with disease within 1 year. Both carcinomatous and sarcomatous elements are present in all the tumors. Squamous differentiation was noted in two cases. Heterologous elements, including chondroid, rhabodomyoblastic, and osteoid differentiation were detected in all tumors. Immunohistochemical studies confirm the biphasic differentiation with variable demonstration of neural and smooth muscle differentiation. All five MMMTs were negative for estrogen and progestogen receptors although the related endometrial and tubal carcinomas were positive. Heteroduplex analysis used to screen for specific BRCA-1 mutations were negative in all five MMMTs. Clonality study of the two MMMTs found in association with endometrial carcinoma and tubal carcinoma was inconclusive. CONCLUSIONS Our study confirmed that primary peritoneal MMMTs were aggressive tumors with poor prognosis. The presence of synchronous or metachronous genital carcinomas suggests multifocal tumorigenesis from tissue of same embryologic origin. The lack of hormone receptor in these tumors indicates deviation from hormonal control. Specific BRCA-1 mutations found in ovarian carcinoma in Chinese patients could not be detected in our series.
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Affiliation(s)
- D H Shen
- Department of Pathology, People's Hospital, Beijing Medical University, Beijing, China
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Affiliation(s)
- Y K Chan
- Department of Anesthesia, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Chiu CL, Chan YK, Ong GS, Delilkan AE. A comparison of the maintenance and recovery charcateristic of sevoflurane-nitrous oxide against isoflurane-nitrous oxide anaesthesia. Singapore Med J 2000; 41:530-3. [PMID: 11284610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
BACKGROUND To compare the maintenance and recovery characteristics of sevoflurane and isoflurane anaesthesia in Malaysian patients. METHOD This is a prospective, open labelled, randomized, controlled study. Sixty unpremedicated ASA I or II patients (aged 18-50 years), scheduled for elective breast lump excision were randomly allocated to receive either isoflurane or sevoflurane for the maintenance of anaesthesia following fentanyl and propofol intravenous induction. The systolic, diastolic, mean arterial blood pressure and heart rate were measured. The speed of recovery was measured by time to eye opening, time to following simple command, and time to correctly giving own names and address. The incidence of postoperative complication was also recorded. RESULTS The trend of systolic blood pressure was significantly higher in the isoflurane group as compared to the sevoflurane group for the duration of anaesthesia (p < 0.001, by ANOVA for repeated measurement) but the trend of heart rate was similar for both groups. The recovery time was faster in the isoflurane group. [mean time of eye opening (SD) = 6.8 (2.2) vs 10.7 (4.4) min, p < 0.001; mean time of sticking tongue out (SD) = 7.9 (2.9) vs 11.5 (4.7) min, p < 0.01; mean time of giving own name (SD) = 7.8 (2.7) vs 11.8 (4.8) min, p < 0.001, mean time of giving own address (SD) = 8.4 (2.9) vs 12.0 (4.7) min, p < 0.01]. No major adverse effects were encountered postoperatively and the incidences of minor adverse effects were low in both groups. CONCLUSION We concluded that sevoflurane is a safe alternative to isoflurane but in these short procedures, awakening time was surprisingly slower than after isoflurane.
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Affiliation(s)
- C L Chiu
- Department of Anaesthesia, University of Malaya Medical Centre, Kuala Lumpur, Malaysia
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Abstract
We present a case of headache following epidural anaesthesia for caesarean section. The patient did not exhibit the classical features of post dural puncture headache and the cause was uncertain. The headache was complicated by post partum seizure and a history of pregnancy-induced hypertension. A diagnostic lumbar puncture had to be done to exclude meningitis as she had a raised white blood count. An epidural blood patch performed 12 days post partum resolved the headache immediately.
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Affiliation(s)
- C L Chiu
- Department of Anaesthesia, University of Malaya Medical Centre, Kuala Lumpur, Malaysia.
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46
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Abstract
A survey was conducted in several countries in the Far East in an attempt to determine the practice of obstetric analgesia and anaesthesia there. Survey forms were sent to a total of 11 countries but in the end responses from only four countries were able to provide useful information. Responses from Singapore, Hong Kong, Taiwan and Malaysia covered between 44.9% (Singapore) and 24.6% (Malaysia) of their countries' total deliveries in 1997 and were thought to be adequate to give an impression of the obstetric analgesia and anaesthesia services in their respective countries, although this would not necessarily be completely accurate. From our survey, we found that the availability of regional analgesia for labour paralleled the economic status of the country and that a significant number of caesarean sections are conducted under regional anaesthesia, mainly spinals.
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Affiliation(s)
- Y K Chan
- Department of Anaesthesiology, University of Malaya Medical Centre, Kuala Lumpur, Malaysia.
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Flather MD, Weitz JI, Yusuf S, Pogue J, Sussex B, Campeau J, Gill J, Schuld R, Joyner CD, Morris AL, Lai C, Théroux P, Marquis JF, Chan YK, Venkatesh G, Jessel A. Reactivation of coagulation after stopping infusions of recombinant hirudin and unfractionated heparin in unstable angina and myocardial infarction without ST elevation: results of a randomized trial. OASIS Pilot Study Investigators. Organization to Assess Strategies for Ischemic++ Syndromes. Eur Heart J 2000; 21:1473-81. [PMID: 10952840 DOI: 10.1053/euhj.1999.2005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
AIMS To compare effects of heparin and hirudin on biochemical markers of coagulation. METHODS AND RESULTS Patients (n=395) with unstable angina or myocardial infarction without ST elevation were randomized to a 72-h infusion of one of three regimens: unfractionated heparin (bolus of 5000 IU followed by an infusion of 1200 IU. h(-1)), low-dose hirudin (HBW 023; 0.2 mg. kg(-1)bolus followed by 0.10 mg. kg(-1). h(-1)) or medium-dose hirudin (0.4 mg. kg(-1)bolus followed by 0.15 mg. kg(-1). h(-1)). Infusions were adjusted to maintain an activated partial thromboplastin time of between 60-100 s. Activated partial thromboplastin time, prothrombin fragment 1.2 (F1.2), thrombin antithrombin III complex and D-dimer were measured before, during and after the infusion. Median activated partial thromboplastin time was similar in the two groups early on, but was significantly lower in the heparin group than in the combined hirudin group 48 h after starting the infusion (53 s and 75 s, respectively;P<0.001), and 6 h after stopping (31 s and 46 s, respectively;P<0.001). Median F1.2 levels were not significantly different between the groups during the infusion. Median thrombin antithrombin III levels in the heparin and hirudin groups were 2.8 microg. l(-1)and 2.3 microg. l(-1), respectively, at 6 h (P<0.001), and 3.0 microg. l(-1)and 2.3 microg. l(-1), respectively, at 48 h (P<0.001). Median D-dimer levels were 320 ng. ml(-1)and 260 ng. ml(-1)48 h after starting the infusion in the heparin and hirudin groups, respectively (P<0.001), and 415 ng. ml(-1)and 280 ng. ml(-1), respectively (P<0.001) 6 h after stopping. D-dimer levels were significantly elevated above baseline values in both groups 24-48 h after stopping the infusions. CONCLUSIONS The greater reduction of thrombin antithrombin III and D-dimer during the hirudin infusion supports the hypothesis that hirudin is a more potent antithrombin agent than heparin. Increased D-dimer levels after stopping heparin or hirudin suggest that there is an ongoing pro-coagulant state. These results point to the greater efficacy of hirudin in preventing early clinical events (death, myocardial infarction and refractory ischaemia) compared with heparin that have been observed in large randomized trials. Persistent activation of coagulation afterstopping infusions in our study suggests that a longer course of antithrombotic treatment may be needed to pacify the thrombus.
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Affiliation(s)
- M D Flather
- Hamilton Health Sciences Corporation Research Centre, Hamilton, Ontario, Canada
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48
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Abstract
A healthy parturient under spinal anaesthesia for Caesarean section lost consciousness for an hour, 20 min after the intrathecal injection of 2 ml of 0.5% heavy bupivacaine. The patient was haemodynamically stable before losing consciousness. The differential diagnosis is discussed.
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Affiliation(s)
- Y K Chan
- Department of Anaesthesiology, Faculty of Medicine, University of Malaya Medical Centre, Kuala Lumpur, Malaysia
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Abstract
OBJECTIVES To prospectively study the intervention rate, duration of labour, malpositions, fetal outcome, maternal satisfaction, voiding complications and adverse events in healthy primigravidae in spontaneous labour at term following epidural analgesia. METHODS A prospective randomized study involving 55 patients in the epidural group and 68 in the control pethidine--inhalational entonox group. RESULTS There were significantly more obstetric interventions (instrumental deliveries) in the epidural group (p < 0.01). The total duration of labour and the duration of the second stage was prolonged in the epidural group (p < 0.01). There were more malpositions at the second stage of labour in the epidural group (p < 0.02). There were no differences in fetal outcome (Apgar scores and Special Care Nursery admissions). Patients in the epidural group were consistently happier with their method of pain relief (p < 0.01). Two patients required blood patches while another 2 patients had persistent backache post epidural analgesia. CONCLUSION Epidural analgesia in primigravidae in spontaneous labour at term led to an increased instrumental delivery rate, prolonged duration of labour, greater rate of malpositions in the second stage, increased oxytocin requirements but with no difference in fetal outcomes but with happier mothers as compared to the control group.
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Affiliation(s)
- E W Leong
- Department of Obstetrics and Gynaecology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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50
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Tsui WM, Lam PW, Lee KC, Ma KF, Chan YK, Wong MW, Yip SP, Wong CS, Chow AS, Lo ST. The C282Y mutation of the HFE gene is not found in Chinese haemochromatotic patients: multicentre retrospective study. Hong Kong Med J 2000; 6:153-8. [PMID: 10895137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
OBJECTIVE To detect two novel mutations (C282Y and H63D) of the HFE gene in Chinese patients with hepatic iron overload. DESIGN Multicentre retrospective study. SETTING Four public hospitals, Hong Kong. PARTICIPANTS Fifty Chinese patients who presented from January 1987 through December 1999 with hepatic iron overload from various causes. MAIN OUTCOME MEASURES The DNA from liver biopsy samples was tested for HFE mutations by restriction fragment length polymorphism analysis. RESULTS The sample DNA quality was unsatisfactory for analysis of the C282Y mutation in one case and the H63D mutation in nine cases. The C282Y mutation was not detected in any of the 49 satisfactory samples. Three of the 41 samples were heterozygous for the H63D mutation and only one was homozygous, giving an allele frequency of 6.1%. Of the three H63D-heterozygotes, one had beta-thalassaemia major, one had beta-thalassaemia minor, and one had hereditary spherocytosis. None of the 12 patients who were presumed to have primary haemochromatosis were positive for either mutation. CONCLUSIONS The classical form of human leukocyte antigen-linked hereditary haemochromatosis appears to be absent form this locality. The H63D mutation is found in a minority (9.8%) of the patients, in whom it may act synergistically with an erythropoietic factor.
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Affiliation(s)
- W M Tsui
- Department of Pathology, Caritas Medical Centre, Kowloon, Hong Kong
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