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Impara E, Bakolis I, Bécares L, Dasch H, Dregan A, Dyer J, Hotopf M, Stewart RJ, Stuart R, Ocloo J, Das-Munshi J. COVID-19 ethnic inequalities in mental health and multimorbidities: protocol for the COVEIMM study. Soc Psychiatry Psychiatr Epidemiol 2022; 57:2511-2521. [PMID: 35737082 PMCID: PMC9219393 DOI: 10.1007/s00127-022-02305-y] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 05/05/2022] [Indexed: 11/29/2022]
Abstract
PURPOSE The COVID-19 pandemic may have exacerbated ethnic health inequalities, particularly in people with multiple long-term health conditions, the interplay with mental health is unclear. This study investigates the impact of the pandemic on the association of ethnicity and multimorbidity with mortality/service use among adults, in people living with severe mental illnesses (SMI). METHODS This study will utilise secondary mental healthcare records via the Clinical Record Interactive Search (CRIS) and nationally representative primary care records through the Clinical Practice Interactive Research Database (CPRD). Quasi-experimental designs will be employed to quantify the impact of COVID-19 on mental health service use and excess mortality by ethnicity, in people living with severe mental health conditions. Up to 50 qualitative interviews will also be conducted, co-produced with peer researchers; findings will be synthesised with quantitative insights to provide in-depth understanding of observed associations. RESULTS 81,483 people in CRIS with schizophrenia spectrum, bipolar or affective disorder diagnoses, were alive from 1st January 2019. Psychiatric multimorbidities in the CRIS sample were comorbid somatoform disorders (30%), substance use disorders (14%) and personality disorders (12%). In CPRD, of 678,842 individuals with a prior probable diagnosis of COVID-19, 1.1% (N = 7493) had an SMI diagnosis. People in the SMI group were more likely to die (9% versus 2% in the non-SMI sample) and were more likely to have mental and physical multimorbidities. CONCLUSION The effect of COVID-19 on people from minority ethnic backgrounds with SMI and multimorbidities remains under-studied. The present mixed methods study aims to address this gap.
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Affiliation(s)
- E Impara
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - I Bakolis
- Centre for Implementation Science, Health Services, Population and Research Department, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK
- Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | | | - H Dasch
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - A Dregan
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - J Dyer
- Black Thrive Global, NHS-E/I, London, UK
| | - M Hotopf
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK
- South London and Maudsley NHS Foundation Trust, London, UK
| | - R J Stewart
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK
- South London and Maudsley NHS Foundation Trust, London, UK
| | - R Stuart
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - J Ocloo
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK
- Centre for Implementation Science, Health Services, Population and Research Department, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK
- National Institute for Health Research (NIHR) Applied Research Collaboration South London (NIHR ARC South London) At King's College Hospital NHS Foundation Trust, London, UK
| | - J Das-Munshi
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK.
- South London and Maudsley NHS Foundation Trust, London, UK.
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Stewart RJ, Abdelghafour K, Abdelhakim-Edres K, Sokota S, Narang K, Ray A. 1017 Early Mobilisation After Stable Distal Radius Fracture – an Audit of BOAST Guideline Adherence. Br J Surg 2022. [DOI: 10.1093/bjs/znac269.488] [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: 11/06/2022]
Abstract
Abstract
Aim
Distal radius (DR) fractures are among the commonest fractures seen by orthopaedics. The management of these fractures is dependent on the stability of the fracture, and conservative management is usually favoured for stable fractures. Mobilisation of the wrist following this stable fracture is necessary to avoid the risks of wrist stiffness, complex regional pain syndrome and limitation of function. According to BOAST guidelines for management of DR fractures: patients with a stable fracture should be considered for early mobilisation with a removable support once pain allows. The aim of this study was to determine our unit's adherence to guidelines and review the period of immobilisation of stable DR fractures.
Method
Retrospective analysis of virtual fracture clinic referrals, ED and clinic notes, imaging and any further correspondence of patients referred to our orthopaedic team between 1/2/20–30/7/20 with isolated DR fracture.
Results
Of 163 patients referred with DR fracture, 49.7% were deemed to have a stable fracture. Of these patients, only 37% were mobilised early, with the remainder fully immobilised for 6 weeks without active mobilisation protocol.
Conclusions
A large proportion of patients with stable fractures are not being managed in accordance with BOAST guidelines, therefore a standardised intervention is needed to ensure patients regain maximum possible function. We propose that a new protocol is put in place to screen all DR fractures within our virtual fracture clinic into stable v. unstable pattern and if deemed stable to ensure patient is seen for early physiotherapy face to face or virtually.
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Affiliation(s)
- RJ Stewart
- Chelsea & Westminster Hospital , London , United Kingdom
| | | | | | - S Sokota
- Worthing Hospital , Worthing , United Kingdom
| | - K Narang
- Worthing Hospital , Worthing , United Kingdom
| | - A Ray
- Worthing Hospital , Worthing , United Kingdom
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Morton H, Pedley KC, Stewart RJ, Coad J. Vitamin D concentrations in New Zealanders with and without inflammatory bowel disease: do they differ? N Z Med J 2020; 133:61-70. [PMID: 32161422] [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: 06/10/2023]
Abstract
AIM Patients with inflammatory bowel disease (IBD), Crohn's disease (CD) or ulcerative colitis (UC) are at risk of low vitamin D owing to reduced absorption, medication-associated sunlight exposure restrictions and/or increased requirements due to inflammation. This study aimed to determine if the serum vitamin D concentration of New Zealand IBD patients relates to disease activity and differs from controls. METHOD Data concerning demographics, sunlight exposure, vitamin D supplementation and disease activity were collected using a retrospective questionnaire. Serum vitamin D concentrations were measured in dried blood spots and validated against blood samples in a participant sub-group. RESULTS Vitamin D concentration was significantly increased by supplementation (82.8 v 66.4nmol/L, p<0.001) and sunlight exposure while on holiday (75.2 v 63.7nmol/L, p<0.001). Patients with CD who reported active disease in the last year had significantly lower vitamin D concentrations (68.6 v 84.6nmol/L, p=0.008) than those who reported remaining in remission. CONCLUSION In this cohort of New Zealand residents, mean vitamin D of patients with IBD was not different from controls. In patients with CD, recent disease activity was significantly associated with lower vitamin D. The use of vitamin D supplementation may have implications for reducing disease activity occurrence in patients with CD.
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Affiliation(s)
- Hannah Morton
- PhD student, School of Food and Advanced Technology, College of Sciences, Massey University, Palmerston North
| | - Kevin C Pedley
- Hon Associate Professor, Massey University, Palmerston North
| | - Robin Jc Stewart
- Lecturer, School of Applied Science, Faculty of Health and Sciences, Universal College of Learning, Palmerston North
| | - Jane Coad
- Professor, School of Food and Advanced Technology, College of Sciences, Massey University, Palmerston North
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Abstract
INTRODUCTION There has been regular dialogue regarding the importance of developing clinical networks to compensate for the steady decline in general paediatric surgery performed by adult surgeons. Despite this dialogue, there are no contemporary published data to quantify the issue. This report documents patterns in delivery of general paediatric surgery in England and shows what is being performed where and by whom. MATERIALS AND METHODS Using the Surgical Workload Outcome Database, we compared hospital-level data between 2009 and 2017. Inclusion criteria were children under 18 years admitted to NHS hospitals in England for elective general paediatric surgery. Data were analysed with an online statistical package performing paired t-tests. RESULTS There was no real change in the overall number of elective general paediatric surgical marker cases, but the type mix has changed. The number of marker cases performed by adult surgeons fell by 34% (4699 vs 3090 p < 0.05). The number of marker cases performed by specialist paediatric surgeons increased by 21% (8184 vs 9862 p < 0.05). This increase in workload occurred in both tertiary (21% increase) and peripheral (18% increase) centres. When analysing data by operation type it was apparent that 78% of the increased workload was attributable to an increase in orchidopexy rate. CONCLUSION Best practice is to treat children close to home by staff with the right skills. This study shows significant shifts in the general paediatric surgical workload. It is important to monitor these trends for successful succession planning as well as configuration of services.
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Stewart RJ, Rossow J, Conover JT, Lobelo EE, Eckel S, Signs K, Stobierski MG, Trock SC, Fry AM, Olsen SJ, Biggerstaff M. Do animal exhibitors support and follow recommendations to prevent transmission of variant influenza at agricultural fairs? A survey of animal exhibitor households after a variant influenza virus outbreak in Michigan. Zoonoses Public Health 2017; 65:195-201. [PMID: 29143461 PMCID: PMC6631301 DOI: 10.1111/zph.12425] [Citation(s) in RCA: 4] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Indexed: 11/30/2022]
Abstract
Influenza A viruses circulate in swine and can spread rapidly among swine when housed in close proximity, such as at agricultural fairs. Youth who have close and prolonged contact with influenza-infected swine at agricultural fairs may be at increased risk of acquiring influenza virus infection from swine. Animal and human health officials have issued written measures to minimize influenza transmission at agricultural exhibitions; however, there is little information on the knowledge, attitudes, and practice (KAP) of these measures among animal exhibitors. After an August 2016 outbreak of influenza A(H3N2) variant (“H3N2v”) virus infections (i.e., humans infected with swine influenza viruses) in Michigan, we surveyed households of animal exhibitors at eight fairs (including one with known H3N2v infections) to assess their KAP related to variant virus infections and their support for prevention measures. Among 170 households interviewed, most (90%, 151/167) perceived their risk of acquiring influenza from swine to be low or very low. Animal exhibitor households reported high levels of behaviours that put them at increased risk of variant influenza virus infections, including eating or drinking in swine barns (43%, 66/154) and hugging, kissing or snuggling with swine at agricultural fairs (31%, 48/157). Among several recommendations, including limiting the duration of swine exhibits and restricting eating and drinking in the animal barns, the only recommendation supported by a majority of households was the presence of prominent hand-washing stations with a person to monitor hand-washing behaviour (76%, 129/170). This is a unique study of KAP among animal exhibitors and highlights that animal exhibitor households engage in behaviours that could increase their risk of variant virus infections and have low support for currently recommended measures to minimize infection transmission. Further efforts are needed to understand the lack of support for recommended measures and to encourage healthy behaviours at fairs.
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Affiliation(s)
- R J Stewart
- Epidemic Intelligence Service, CDC, Atlanta, GA, USA.,Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - J Rossow
- Epidemiology Elective Program, Division of Scientific Education and Professional Development, Center for Surveillance, Epidemiology, and Laboratory Services, Atlanta, GA, USA.,University of Georgia College of Veterinary Medicine, Athens, GA, USA
| | - J T Conover
- Michigan State University Extension, East Lansing, MI, USA
| | - E E Lobelo
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - S Eckel
- Michigan Department of Health and Human Services, Lansing, MI, USA
| | - K Signs
- Michigan Department of Health and Human Services, Lansing, MI, USA
| | - M G Stobierski
- Michigan Department of Health and Human Services, Lansing, MI, USA
| | - S C Trock
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - A M Fry
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - S J Olsen
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - M Biggerstaff
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Papanna R, Moise KJ, Mann LK, Fletcher S, Schniederjan R, Bhattacharjee MB, Stewart RJ, Kaur S, Prabhu SP, Tseng SCG. Cryopreserved human umbilical cord patch for in-utero spina bifida repair. Ultrasound Obstet Gynecol 2016; 47:168-176. [PMID: 26489897 DOI: 10.1002/uog.15790] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 10/08/2015] [Accepted: 10/09/2015] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To identify a patch system to repair surgically created spina bifida in a sheep model for its efficacy in healing the skin defect, protecting the underlying spinal cord and reducing the Chiari II malformation. METHODS Spina bifida was created surgically in 16 fetuses from eight timed-pregnant sheep at gestational age of 75 days. Two fetuses did not survive the procedure. Repeat hysterotomy was performed at 95 days' gestation to cover the defect with either biocellulose film with underwater adhesive (BCF-adhesive) (n = 7) or human umbilical cord with suture (HUC-suture) (n = 7). Three fetuses without formation of the defect served as reference controls. The skin healing was examined by direct visualization after a planned Cesarean section at term, followed by histological analysis using hematoxylin and eosin and Masson's trichrome stains. Mid-sagittal sections of the fetal cranium and upper cervical spine were analyzed by a pediatric neuroradiologist who was blinded to the type of patch received. RESULTS Three fetuses that received the BCF-adhesive and six fetuses that received the HUC-suture survived to term for final analysis. As a result of dislodgment of the BCF-adhesive, all spina bifida defects repaired using BCF-adhesive were not healed and showed exposed spinal cord with leakage of cerebrospinal fluid. In contrast, all spinal defects repaired by HUC-suture were healed with complete regrowth of epidermal, dermal and subdermal tissue components, with no exposed spinal cord. The maximal skin wound width was 21 ± 3.6 mm in the BCF-adhesive group but 3 ± 0.8 mm in the HUC-suture group (P < 0.001). The spinal cord area (P = 0.001) and the number of anterior horn cells (P = 0.03) was preserved to a greater degree in the HUC-suture group than in the BCF-adhesive group, whilst psammoma bodies, signifying neuronal degeneration, were only observed in the BCF-adhesive group. Anatomic changes, indicative of Chiari II malformation, were seen in all three fetuses of the BCF-adhesive group but in none of the HUC-suture group (P < 0.01). CONCLUSION Cryopreserved umbilical cord graft is a promising regenerative patch for intrauterine repair of spina bifida.
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Affiliation(s)
- R Papanna
- Department of Obstetrics, Gynecology and Reproductive Medicine, Division of Maternal-Fetal Medicine, UT Health School of Medicine, Houston, TX, USA
- Fetal Center, Houston, TX, USA
| | - K J Moise
- Department of Obstetrics, Gynecology and Reproductive Medicine, Division of Maternal-Fetal Medicine, UT Health School of Medicine, Houston, TX, USA
- Fetal Center, Houston, TX, USA
| | - L K Mann
- Department of Obstetrics, Gynecology and Reproductive Medicine, Division of Maternal-Fetal Medicine, UT Health School of Medicine, Houston, TX, USA
- Department of Pathology and Laboratory Services, UT Health School of Medicine, Houston, TX, USA
| | - S Fletcher
- Department of Pediatrics, Division of Pediatric Neurosurgery, UT Health School of Medicine, Houston, TX, USA
| | - R Schniederjan
- Department of Pediatric Surgery, UT Health School of Medicine, Houston, TX, USA
| | - M B Bhattacharjee
- Department of Pediatric Surgery, UT Health School of Medicine, Houston, TX, USA
| | - R J Stewart
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
| | - S Kaur
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
| | - S P Prabhu
- Department of Radiology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - S C G Tseng
- Ocular Surface Center and TissueTech, Inc., Miami, FL, USA
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Papanna R, Mann LK, Tseng SCG, Stewart RJ, Kaur SS, Swindle MM, Kyriakides TR, Tatevian N, Moise KJ. Cryopreserved human amniotic membrane and a bioinspired underwater adhesive to seal and promote healing of iatrogenic fetal membrane defect sites. Placenta 2015; 36:888-94. [PMID: 26059341 DOI: 10.1016/j.placenta.2015.05.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [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: 12/06/2014] [Revised: 03/27/2015] [Accepted: 05/21/2015] [Indexed: 11/27/2022]
Abstract
INTRODUCTION We investigated the ability of cryopreserved human amniotic membrane (hAM) scaffold sealed with an underwater adhesive, bio-inspired by marine sandcastle worms to promote healing of iatrogenic fetal membrane defects in a pregnant swine model. METHODS Twelve Yucatan miniature pigs underwent laparotomy under general anesthesia at 70 days gestation (term = 114 days). The gestational sacs were assigned to uninstrumented (n = 24) and instrumented with 12 Fr trocar, which was further randomized into four different arms-no hAM patch, (n = 22), hAM patch secured with suture (n = 16), hAM patch with no suture (n = 14), and hAM patch secured with adhesive (n = 9). The animals were euthanized 20 days after the procedure. Gross and histological examination of the entry site was performed for fetal membrane healing. RESULTS There were no differences in fetal survival, amniotic fluid levels, or dye-leakage from the amniotic cavity between the groups. The fetal membranes spontaneously healed in instrumented sacs without hAM patches. In sacs with hAM patches secured with sutures, the patch was incorporated into the swine fetal membranes. In sacs with hAM patches without sutures, 100% of the patches were displaced from the defect site, whereas in sacs with hAM patches secured with adhesive 55% of the patches remained in place and showed complete healing (p = 0.04). DISCUSSION In contrast to humans, swine fetal membranes heal spontaneously after an iatrogenic injury and thus not an adequate model. hAM patches became incorporated into the defect site by cellular ingrowth from the fetal membranes. The bioinspired adhesive adhered the hAM patches within the defect site.
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Affiliation(s)
- R Papanna
- The Fetal Center, Department of Obstetrics, Gynecology and Reproductive Sciences, The University of Texas Medical School, Houston, TX, USA.
| | - L K Mann
- The Fetal Center, Department of Obstetrics, Gynecology and Reproductive Sciences, The University of Texas Medical School, Houston, TX, USA
| | - S C G Tseng
- Research & Development of Tissue Tech, Ocular Surface Center, P.A., Miami, FL, USA
| | - R J Stewart
- Department of Engineering, College of Engineering, The University of Utah, Salt Lake City, UT, USA
| | - S S Kaur
- Department of Engineering, College of Engineering, The University of Utah, Salt Lake City, UT, USA
| | - M M Swindle
- Comparative Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - T R Kyriakides
- Department of Pathology, Yale University, New Haven, CT, USA
| | - N Tatevian
- Department of Pathology, The University of Texas Medical School, Houston, TX, USA
| | - K J Moise
- The Fetal Center, Department of Obstetrics, Gynecology and Reproductive Sciences, The University of Texas Medical School, Houston, TX, USA
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Platt BS, Stewart RJ. Reversible and irreversible effects of protein-calorie deficiency on the central nervous system of animals and man. World Rev Nutr Diet 2015; 13:43-85. [PMID: 4935607 DOI: 10.1159/000391882] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Kim PY, Stewart RJ, Lipson SM, Nesheim ME. The relative kinetics of clotting and lysis provide a biochemical rationale for the correlation between elevated fibrinogen and cardiovascular disease. J Thromb Haemost 2007; 5:1250-6. [PMID: 17266698 DOI: 10.1111/j.1538-7836.2007.02426.x] [Citation(s) in RCA: 36] [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: 11/27/2022]
Abstract
BACKGROUND Elevated plasma fibrinogen is a well known risk factor for cardiovascular disease. The mechanistic rationale for this is not known. OBJECTIVES These studies were carried out to determine the fibrinogen concentration dependencies of clotting and lysis times and thereby determine whether these times rationalize the correlation between an increased risk of cardiovascular disease and elevated plasma fibrinogen. METHODS The time courses of clot formation and lysis were measured by turbidity in systems comprising a) fibrinogen, thrombin and plasmin, or b) fibrinogen, thrombin, plasminogen and t-PA, or c) plasma, thrombin and t-PA. From the lysis times, k(cat) and K(m) values for plasmin action on fibrin were determined. RESULTS The time to clot increased linearly from 2.9 to 5.6 minutes as the fibrinogen concentration increased from 1 to 9 microM and did not increase further as the fibrinogen concentration was raised to 20 microM. In contrast, the clot lysis time increased linearly over the input fibrinogen concentration range of 2 to 20 microM. A similar linear trend was found in the two systems with t-PA and plasminogen. Apparent K(m) and k(cat) values for plasmin were 1.1 +/- 0.6 microM and 28 +/- 2 min(-1), respectively. K(m) values for plasmin in experiments initiated with t-PA and plasminogen were 1.6 +/- 0.2 microM in the purified system and 2.1 +/- 0.9 microM in plasma. CONCLUSION As the concentration of fibrinogen increases, especially above physiologic level, the balance between fibrinolysis and clotting shifts toward the latter, providing a rationale for the increased risk of cardiovascular disease associated with elevated fibrinogen.
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Affiliation(s)
- P Y Kim
- Department of Biochemistry, Queen's University, Kingston, ON, Canada
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Affiliation(s)
- J Millard
- Department of Paediatric Surgery, University of Nottingham Hospitals NHS Trust, Queens Medical Centre, Derby Rd, Nottingham, NG7 2UH, UK
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Abstract
We report a 6-month-old child who presented with recurrent chest infections associated with a right diaphragmatic eventration. Failure in conservative management lead to thoracoscopic plication at 17 months of age and discharge on the third postoperative day. At one year followup he is completely free from all symptoms, and his chest x-ray demonstrates a marked improvement in the position of the diaphragm. We recommend thoracoscopy as a viable approach in treating this condition in children.
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Affiliation(s)
- A Cherian
- Department of Paediatric Surgery, University Hospital Nottingham, Nottingham NG7 2UH, UK
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Pace KT, Dyer SJ, Stewart RJ, Honey RJ, Poulin EC, Schlachta CM, Mamazza J. Health-related quality of life after laparoscopic and open nephrectomy. Surg Endosc 2003; 17:143-52. [PMID: 12399838 DOI: 10.1007/s00464-002-8902-y] [Citation(s) in RCA: 44] [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] [Received: 06/13/2002] [Accepted: 07/08/2002] [Indexed: 11/24/2022]
Abstract
BACKGROUND Postoperative recovery often is assessed with parameters (pain and return to work) susceptible to bias. This study sought objectively to compare postoperative health-related quality of life (HRQL) after laparoscopic and open nephrectomy with the Postoperative Recovery (PRS) (a validated questionnaire designed to assess pain), activities of daily living (ADL), and HRQL in postoperative patients. METHODS Patients undergoing contemporaneous laparoscopic and open nephrectomy received the PRS pre- and postoperatively. The results were analyzed with analysis of covariance (ANCOV) and survival analysis. RESULTS The 33 open nephrectomy and 38 laparoscopic patients in this study were comparable in age, gender, body mass index (BMI) and employment. Laparoscopic operative time was longer (p = 0.015), and the hospital stay was shorter (p<0.001). Laparoscopic patients had higher HRQL scores from postoperative days 3 to 365 (p<0.001), and they returned to preoperative HRQL faster (p<0.001). CONCLUSIONS An objective HRQL instrument confirms that laparoscopic nephrectomy patients recover faster and with a higher HRQL than open surgery patients. The PRS can be modified for use after other abdominal procedures, and may prove useful for comparisons of other minimally invasive surgical techniques.
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Affiliation(s)
- K T Pace
- Division of Urology, St. Michael's Hospital, University of Toronto, Ontario, Canada.
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Pace KT, Dyer SJ, Phan V, Stewart RJ, Honey RJDA, Poulin EC, Schlachta CM, Mamazza J. Laparoscopic versus open donor nephrectomy. Surg Endosc 2003; 17:134-42. [PMID: 12399837 DOI: 10.1007/s00464-002-8901-z] [Citation(s) in RCA: 20] [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] [Subscribe] [Scholar Register] [Received: 06/18/2002] [Accepted: 07/08/2002] [Indexed: 11/25/2022]
Abstract
BACKGROUND As compared with open donor nephrectomy (OpenDN), laparoscopic donor nephrectomy (LapDN) offers donors more rapid recovery and recipients equivalent graft function, but LapDN costs remain greater. This study compared LapDN and OpenDN with cost-utility analysis. METHODS Utilities were assessed with time trade-off, probabilities derived from systematic review of the literature and the costs derived from 27 OpenDN and 34 LapDN patients treated contemporaneously. A societal perspective was taken. Lost employment costs were included. An incremental cost-effectiveness ratio (ICER) was calculated with best- and worst-case scenarios for confidence intervals. Sensitivity analyses assessed robustness. RESULTS LapDN costs are lower (11,170.71 dollars vs 12,631.91 dollars), whereas quality of life (QOL) is superior (0.7247 vs 0.6585 quality-adjusted life years [QALY], rendering LapDN a dominant strategy. The model was robust to all variables, and LapDN remained dominant from a payer perspective. In a worst-case scenario, the ICER for LapDN was at most 2,231.61 dollars per QALY. CONCLUSIONS LapDN offers improved QOL at lower costs, despite the fact that this analysis included patients treated during the learning curve of LapDN at our institution. By potentially increasing organ donor rates, LapDN may be further cost saving by decreasing the number of patients receiving dialysis.
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Affiliation(s)
- K T Pace
- Division of Urology, St. Michael's Hospital, University of Toronto, Ontario, Canada.
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Stewart RJ, Askew EW, McDonald CM, Metos J, Jackson WD, Balon TW, Prior RL. Antioxidant status of young children: response to an antioxidant supplement. J Am Diet Assoc 2002; 102:1652-7. [PMID: 12449290 DOI: 10.1016/s0002-8223(02)90352-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To study oxidative stress indicators in healthy young children and their response to a commercially available fruit- and vegetable-based antioxidant supplement. DESIGN Healthy children were randomly assigned to a placebo and a supplement (commercial antioxidant supplement produced from dried fruit and vegetable extracts and fortified with antioxidants, resembling a gummy-type candy). The placebo and the supplement were taken in 2 doses per day for 21 days. SUBJECTS Participants were 39 children (26 boys and 13 girls) aged 5 to 10 years. Research was conducted at Primary Children's Medical Center and the University of Utah, Salt Lake City. MAIN OUTCOME MEASURES Breath and urine samples were collected on days 1 and 21 and assayed for breath pentane and urine 8-hydroxydeoxyguanosine, malondialdehyde, nitrites, and 8-isoprostane as noninvasive indicators of oxidative stress. Urine oxygen radical absorbance capacity was measured at days 1 and 21 as an indirect indicator of the antioxidant capacity of the body. Three-day food records were collected at the beginning and end of the study to measure intake of dietary fruit; vegetable; and antioxidant vitamins A, C, and E. STATISTICAL ANALYSIS Descriptive statistics, repeated measures analysis of variance, paired t tests, and Pearson r correlations. RESULTS Markers of oxidative stress were not significantly different between the placebo and supplement groups at day 1 or day 21. The oxidative stress indicators of the healthy children in this study appear to be similar to those of healthy adults and were not changed by antioxidant supplementation. The diet record analyses indicated that mean fruit and vegetable intakes (2.75 servings/day) were similar to the national average intake for children in the United States. APPLICATIONS/CONCLUSIONS This research presents original information on the subject of oxidative stress in healthy children. The results of this study may be useful as reference baseline markers to use in conjunction with clinical dietary evaluations and for future research with healthy children and with children in disease states who are subject to elevated levels of oxidative stress.
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Affiliation(s)
- R J Stewart
- St Luke's Wood River Medical Center, Ketchum, ID, USA
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15
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Abstract
Hybrid hydrogels of hydrophilic synthetic polymers cross-linked by protein modules undergo externally triggered volume transitions as a result of protein conformational changes. To investigate the influence of coiled-coil protein structure and stability on hydrogel volume transition, a series of block proteins containing interspersed naturally derived recombinant coiled-coils was synthesized. Proteins were characterized using circular dichroism, size exclusion chromatography, gel electrophoresis, and analytical ultracentrifugation. The block proteins formed self-associating oligomers and displayed thermal unfolding profiles indicative of a hierarchic higher-order structure. Hybrid hydrogels were assembled from an N-(2-hydroxypropyl)-methacrylamide (HPMA) copolymer and His-tagged block proteins through metal complexation. A temperature-induced decrease in hydrogel swelling was observed, and the onset temperature of the volume transition corresponded to the onset temperature of protein unfolding. We conclude that stimuli-responsive properties of hybrid hydrogels can be tailored by engineering the structure and properties of protein cross-links.
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Affiliation(s)
- C Wang
- Departments of Bioengineering and Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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16
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Stewart RJ, Chen B, Dowlatshahi D, MacQueen GM, Young LT. Abnormalities in the cAMP signaling pathway in post-mortem brain tissue from the Stanley Neuropathology Consortium. Brain Res Bull 2001; 55:625-9. [PMID: 11576759 DOI: 10.1016/s0361-9230(01)00524-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [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: 11/16/2022]
Abstract
There is an established relationship between the monoaminergic neurotransmitter system and mood disorders. In an attempt to define further the pathophysiology of mood disorders, research is focussing on intracellular second messenger systems, including cyclic adenosine 3',5'-monophosphate (cAMP) and the polyphosphoinositol generated second messengers. The availability of tissue from the Stanley Foundation Neuropathology Consortium has offered us the opportunity to make a number of observations with respect to these second messenger systems in tissue from patients with major depressive disorder and bipolar affective disorder. There is evidence that antidepressants stimulate components of the cAMP pathway in patients with depression while mood stabilizers blunt the same pathway in patients with bipolar disorder. Furthermore, downstream targets of this pathway appear to be altered in patients with mood disorders. The relations between changes in second messenger systems, gene transcription, and clinical effects of current therapeutic regimens has implications for development of novel treatments of mood disorders.
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Affiliation(s)
- R J Stewart
- Mood Disorders Program, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
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17
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Abstract
Recombinant DNA technology provides a powerful tool for producing protein-based biomaterials. Genetically engineered coiled coils have been used as a structural module for the construction of a variety of bio-based systems useful in drug delivery studies. Two of such approaches developed in the authors' laboratory were described here. One approach was to assemble hybrid hydrogels from coiled coil protein domains and synthetic polymers. Preliminary results showed that temperature-sensitive volume transition of the hybrid hydrogels could be triggered by the thermal unfolding of the engineered coiled coil protein domains. The other approach, discussed in detail, was to construct an epitope display model system based on a coiled coil stem loop peptide self-assembled on a solid substrate. This model construct displayed a constrained nonapeptide sequence, which was found to mediate specific binding with immunocompetent cells bearing complementary surface receptors. These novel approaches will likely find important applications in the rational design of more effective drug delivery systems.
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Affiliation(s)
- A Tang
- Department of Pharmaceutics and Pharmaceutical Chemistry, 30 S 2000 E Rm. 301, University of Utah, Salt Lake City, UT 84112, USA
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18
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Stewart RJ, Varghese JN, Garrett TP, Høj PB, Fincher GB. Mutant barley (1-->3,1-->4)-beta-glucan endohydrolases with enhanced thermostability. Protein Eng 2001; 14:245-53. [PMID: 11391016 DOI: 10.1093/protein/14.4.245] [Citation(s) in RCA: 23] [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] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The similar three-dimensional structures of barley (1-->3)-beta-glucan endohydrolases and (1-->3,1-->4)-beta-glucan endohydrolases indicate that the enzymes are closely related in evolutionary terms. However, the (1-->3)-beta-glucanases hydrolyze polysaccharides of the type found in fungal cell walls and are members of the pathogenesis-related PR2 group of proteins, while the (1-->3,1-->4)-beta-glucanases function in plant cell wall metabolism. The (1-->3)-beta-glucanases have evolved to be significantly more stable than the (1-->3,1-->4)-beta-glucanases, probably as a consequence of the hostile environments imposed upon the plant by invading microorganisms. In attempts to define the molecular basis for the differences in stability, eight amino acid substitutions were introduced into a barley (1-->3,1-->4)-beta-glucanase using site-directed mutagenesis of a cDNA that encodes the enzyme. The amino acid substitutions chosen were based on structural comparisons of the barley (1-->3)- and (1-->3,1-->4)-beta-glucanases and of other higher plant (1-->3)-beta-glucanases. Three of the resulting mutant enzymes showed increased thermostability compared with the wild-type (1-->3,1-->4)-beta-glucanase. The largest increase in stability was observed when the histidine at position 300 was changed to a proline (mutant H300P), a mutation that was likely to decrease the entropy of the unfolded state of the enzyme. Furthermore, the three amino acid substitutions which increased the thermostability of barley (1-->3,1-->4)-beta-glucanase isoenzyme EII were all located in the COOH-terminal loop of the enzyme. Thus, this loop represents a particularly unstable region of the enzyme and could be involved in the initiation of unfolding of the (1-->3,1-->4)-beta-glucanase at elevated temperatures.
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Affiliation(s)
- R J Stewart
- Department of Plant Science, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Biomolecular Research Institute, 343 Royal Parade, Parkville, Vic 3052
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19
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Lee AY, Fredenburgh JC, Stewart RJ, Rischke JA, Weitz JI. Like fibrin, (DD)E, the major degradation product of crosslinked fibrin, protects plasmin from inhibition by alpha2-antiplasmin. Thromb Haemost 2001; 85:502-8. [PMID: 11307822] [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
Plasmin generation is localized to the fibrin surface because tissue-type plasminogen activator (t-PA) and plasminogen bind to fibrin, an interaction that stimulates plasminogen activation over a hundred-fold. To ensure efficient fibrinolysis, plasmin bound to fibrin is protected from inhibition by alpha2-antiplasmin. (DD)E, a major soluble degradation product of cross-linked fibrin that is a potent stimulator of t-PA, compromises the fibrin-specificity of t-PA by promoting systemic activation of plasminogen. In this study we investigated whether (DD)E also protects plasmin from inhibition by alpha2-antiplasmin, facilitating degradation of this soluble t-PA effector. (DD)E and fibrin reduce the rate of plasmin inhibition by alpha2-antiplasmin by 5- and 10-fold, respectively. Kringle-dependent binding of plasmin to (DD)E and fibrin, with Kd values of 52 and 410 nM, respectively, contributes to the protective effect. When (DD)E is extensively degraded by plasmin, yielding uncomplexed fragment E and (DD), protection of plasmin from inhibition by alpha2-antiplasmin is attenuated. These studies indicate that (DD)E-bound plasmin, whose generation reflects the ability of (DD)E to stimulate plasminogen activation by t-PA, has the capacity to degrade (DD)E by virtue of its resistance to inhibition. This provides a mechanism to limit the concentration of (DD)E and maintain the fibrin-specificity of t-PA.
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Affiliation(s)
- A Y Lee
- Department of Medicine, McMaster University and Hamilton Civic Hospitals Research Centre, Ontario, Canada
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20
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Stewart RJ, Panigrahy D, Flynn E, Folkman J. Vascular endothelial growth factor expression and tumor angiogenesis are regulated by androgens in hormone responsive human prostate carcinoma: evidence for androgen dependent destabilization of vascular endothelial growth factor transcripts. J Urol 2001; 165:688-93. [PMID: 11176459 DOI: 10.1097/00005392-200102000-00095] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [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: 01/16/2023]
Abstract
PURPOSE The hormonally regulated growth of some human carcinomas represents an important therapeutic target. We report that androgens modulate the angiogenic activity of hormone responsive human prostate cancer. MATERIALS AND METHODS To define further the critical mechanisms underlying hormone responsiveness we examined the angiogenic mediator, vascular endothelial growth factor messenger (m) RNA and protein in response to androgens in vitro as well as the angiogenic response of xenografts of human prostate cancer after androgen withdrawal in vivo. RESULTS In vitro androgen deprivation of LnCaP prostate cancer cells led to decreased vascular endothelial growth factor mRNA and protein expression as well as a 5-fold destabilization in vascular endothelial growth factor mRNA transcripts. In addition, androgen withdrawal inhibited the hypoxic induction of vascular endothelial growth factor mRNA. In mice bearing LnCaP tumors castration resulted in a rapid decrease in mRNA expression and markedly reduced tumor neovascularization. CONCLUSIONS These findings implicate sex steroids as an important stimulus for vascular endothelial growth factor regulation in hormone sensitive tumors and demonstrate the reversal of neovascularization after hormone withdrawal as an early event in the tumor response to therapy.
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Affiliation(s)
- R J Stewart
- Department of Surgery, University of Toronto, Toronto, Ontario, Canada
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21
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Livingston FM, Messoloras S, Newman RC, Pike BC, Stewart RJ, Binns MJ, Brown WP, Wilkes JG. An infrared and neutron scattering analysis of the precipitation of oxygen in dislocation-free silicon. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/17/34/025] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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22
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Stewart RJ, Fredenburgh JC, Rischke JA, Bajzar L, Weitz JI. Thrombin-activable fibrinolysis inhibitor attenuates (DD)E-mediated stimulation of plasminogen activation by reducing the affinity of (DD)E for tissue plasminogen activator. A potential mechanism for enhancing the fibrin specificity of tissue plasminogen activator. J Biol Chem 2000; 275:36612-20. [PMID: 10970891 DOI: 10.1074/jbc.m005483200] [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] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A complex of d-dimer noncovalently associated with fragment E ((DD)E), a degradation product of cross-linked fibrin that binds tissue plasminogen activator (t-PA) and plasminogen (Pg) with affinities similar to those of fibrin, compromises the fibrin specificity of t-PA by stimulating systemic Pg activation. In this study, we examined the effect of thrombin-activable fibrinolysis inhibitor (TAFI), a latent carboxypeptidase B (CPB)-like enzyme, on the stimulatory activity of (DD)E. Incubation of (DD)E with activated TAFI (TAFIa) or CPB (a) produces a 96% reduction in the capacity of (DD)E to stimulate t-PA-mediated activation of Glu- or Lys-Pg by reducing k(cat) and increasing K(m) for the reaction; (b) induces the release of 8 mol of lysine/mol of (DD)E, although most of the stimulatory activity is lost after release of only 4 mol of lysine/mol (DD)E; and (c) reduces the affinity of (DD)E for Glu-Pg, Lys-Pg, and t-PA by 2-, 4-, and 160-fold, respectively. Because TAFIa- or CPB-exposed (DD)E produces little stimulation of Glu-Pg activation by t-PA, (DD)E is not degraded into fragment E and d-dimer, the latter of which has been reported to impair fibrin polymerization. These data suggest a novel role for TAFIa. By attenuating systemic Pg activation by (DD)E, TAFIa renders t-PA more fibrin-specific.
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Affiliation(s)
- R J Stewart
- Hamilton Civic Hospitals Research Centre and McMaster University, Hamilton, Ontario L8V 1C3, Canada
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23
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24
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Abstract
The ncd protein is a dimeric, ATP-powered motor that belongs to the kinesin family of microtubule motor proteins. Here we resolve single mechanochemical cycles of recombinant, dimeric, full-length ncd, using optical-tweezers-based instrumentation and a three-bead, suspended-microtubule assay. Under conditions of limiting ATP, isolated and transient microtubule-binding events exhibit exponentially distributed and ATP-concentration-dependent lifetimes. These events do not involve consecutive steps along the microtubule, quantitatively confirming that ncd is non-processive. At low loads, a single motor molecule produces ATP-triggered working strokes of about 9 nm, which occur at the ends of binding events.
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Affiliation(s)
- M J deCastro
- Department of Bioengineering, University of Utah, Salt Lake City, Utah 84112, USA
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25
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Abstract
The I28 immunoglobulin (Ig)-like module of human cardiac titin, an elastic muscle protein, was used to cross-link acrylamide (AAm) copolymers into hybrid hydrogels. Cross-linking was accomplished through metal coordination bonding between terminal histidine tags (His tags) of the I28 module and metal-chelating nitrilotriacetic acid (NTA)-containing side chains on the copolymer. In solution, the beta-sheet structure of the I28 module unfolded with a transition midpoint of about 58 degrees C as the temperature was elevated. Hydrogels cross-linked with the I28 module demonstrated positive temperature responsiveness; they swelled to 3 times their initial volume at temperatures above the melting temperature of the cross-links. Positive temperature responsiveness is unusual for synthetic hydrogels. The I28 hybrid hydrogels demonstrate that cross-linking synthetic polymers with natural, well-characterized protein modules is a practical strategy for creating new materials with unique environmental responsiveness predictably determined by the mechanical properties of the protein cross-links. These new materials may be useful for controlled chemical delivery.
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Affiliation(s)
- L Chen
- Department of Bioengineering and Department of Pharmaceutics and Pharmaceutical Chemistry, 20 South 2030 East, Room 506, University of Utah, Salt Lake City, Utah 84112, USA
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26
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Pavlovich CP, Kräling BM, Stewart RJ, Chen X, Bochner BH, Luster AD, Poppas DP, O'Donnell MA. BCG-induced urinary cytokines inhibit microvascular endothelial cell proliferation. J Urol 2000; 163:2014-21. [PMID: 10799249] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
PURPOSE Angiogenesis is thought to depend on a net balance of molecules that inhibit or stimulate microvascular endothelial cells. A variety of molecules that affect angiogenesis are induced locally by the administration of intravesical bacille Calmette-Guerin (BCG) for superficial bladder cancer. We sought to determine whether BCG-induced urinary cytokines alter the effects of patient urine on assays of angiogenic activity. MATERIALS AND METHODS Patients undergoing BCG treatment provided urine samples before and at peak cytokine production times after BCG instillation. Fifty-four urine samples from 8 patients were analyzed by ELISA for a panel of molecules known to affect angiogenesis, and tested for angiogenic activity in human dermal microvascular endothelial cell (HDMEC) proliferation and migration assays. To assess the role of specific BCG-induced cytokines, urinary HDMEC proliferation assays were repeated in the presence of neutralizing antibodies to tumor necrosis factor-alpha (TNF-alpha), interferon-inducible protein-10 (IP-10), and/or interferon-gamma (IFN-gamma). RESULTS Urinary IFN-gamma, IP-10, TNF-alpha, and vascular endothelial growth factor (VEGF) were induced to nanogram/ml amounts by BCG treatment. While pre-BCG treatment urine samples minimally stimulated microvascular endothelial cell proliferation (+ 9%), post-BCG treatment urine became progressively inhibitory to endothelial cells (to -85%, p = 0.005) during weekly treatment courses. Neutralizing antibodies to TNF-alpha or to IP-10, either alone or in combination, greatly reduced this inhibitory effect. CONCLUSIONS Intravesical BCG induces a cytokine-rich urinary microenvironment that is inhibitory to human endothelial cells. Urinary cytokine profiles and assays of angiogenic inhibition may provide prognostically important information regarding BCG treatment outcomes.
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Affiliation(s)
- C P Pavlovich
- James Buchanan Brady Foundation, Department of Urology, The New York Hospital - Cornell Medical Center, New York, New York, USA
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27
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Kacher CM, Weiss IM, Stewart RJ, Schmidt CF, Hansma PK, Radmacher M, Fritz M. Imaging microtubules and kinesin decorated microtubules using tapping mode atomic force microscopy in fluids. Eur Biophys J 2000; 28:611-20. [PMID: 10663528 DOI: 10.1007/s002490050001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The atomic force microscope has been used to investigate microtubules and kinesin decorated microtubules in aqueous solution adsorbed onto a solid substrate. The netto negatively charged microtubules did not adsorb to negatively charged solid surfaces but to glass covalently coated with the highly positively charged silane trimethoxysilylpropyldiethylenetriamine (DETA) or a lipid bilayer of 1,2-dipalmitoyl-3-dimethylammoniumpropane. Using electron beam deposited tips for microtubules adsorbed on DETA, single protofilaments could be observed showing that the resolution is up to 5 nm. Under conditions where the silane coated surfaces are hydrophobic, microtubules opened, presumably at the seam, whose stability is lower than that of the bonds between the other protofilaments. This led to a "sheet" with a width of about 100 nm firmly attached to the surface. Microtubules decorated with a stoichiometric low amount of kinesin molecules in the presence of the non-hydrolyzable ATP-analog 5'-adenylylimidodiphosphate could also be adsorbed onto silane-coated glass. Imaging was very stable and the molecules did not show any scan-induced deformation even after hundreds of scans with a scan frequency of 100 Hz.
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Affiliation(s)
- C M Kacher
- Physik Department der TU-München, Institut für Biophysik E22, James-Franck-Strasse, D-85747 Garching, Germany
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28
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Stewart RJ, Fredenburgh JC, Leslie BA, Keyt BA, Rischke JA, Weitz JI. Identification of the mechanism responsible for the increased fibrin specificity of TNK-tissue plasminogen activator relative to tissue plasminogen activator. J Biol Chem 2000; 275:10112-20. [PMID: 10744692 DOI: 10.1074/jbc.275.14.10112] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [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: 11/06/2022] Open
Abstract
TNK-tissue plasminogen activator (TNK-t-PA), a bioengineered variant of tissue-type plasminogen activator (t-PA), has a longer half-life than t-PA because the glycosylation site at amino acid 117 (N117Q, abbreviated N) has been shifted to amino acid 103 (T103N, abbreviated T) and is resistant to inactivation by plasminogen activator inhibitor 1 because of a tetra-alanine substitution in the protease domain (K296A/H297A/R298A/R299A, abbreviated K). TNK-t-PA is more fibrin-specific than t-PA for reasons that are poorly understood. Previously, we demonstrated that the fibrin specificity of t-PA is compromised because t-PA binds to (DD)E, the major degradation product of cross-linked fibrin, with an affinity similar to that for fibrin. To investigate the enhanced fibrin specificity of TNK-t-PA, we compared the kinetics of plasminogen activation for t-PA, TNK-, T-, K-, TK-, and NK-t-PA in the presence of fibrin, (DD)E or fibrinogen. Although the activators have similar catalytic efficiencies in the presence of fibrin, the catalytic efficiency of TNK-t-PA is 15-fold lower than that for t-PA in the presence of (DD)E or fibrinogen. The T and K mutations combine to produce this reduction via distinct mechanisms because T-containing variants have a higher K(M), whereas K-containing variants have a lower k(cat) than t-PA. These results are supported by data indicating that T-containing variants bind (DD)E and fibrinogen with lower affinities than t-PA, whereas the K and N mutations have no effect on binding. Reduced efficiency of plasminogen activation in the presence of (DD)E and fibrinogen but equivalent efficiency in the presence of fibrin explain why TNK-t-PA is more fibrin-specific than t-PA.
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Affiliation(s)
- R J Stewart
- Hamilton Civic Hospitals Research Centre and McMaster University, Hamilton, Ontario L8V 1C3, Canada
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29
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Affiliation(s)
- M U Shenoy
- Department of Paediatric Surgery, University Hospital, Queen's Medical Centre, Nottingham, United Kingdom.
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30
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Affiliation(s)
- M U Shenoy
- Department of Paediatric Surgery, Queen's Medical Centre and University Hospital, Nottingham, UK.
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31
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Weitz JI, Stewart RJ, Fredenburgh JC. Mechanism of action of plasminogen activators. Thromb Haemost 1999; 82:974-82. [PMID: 10605812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- J I Weitz
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
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32
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Abstract
Bacterial bioluminescence, catalyzed by FMN:NAD(P)H oxidoreductase and luciferase, has been used as an analytical tool for quantitating the substrates of NAD(P)H-dependent enzymes. The development of inexpensive and sensitive biosensors based on bacterial bioluminescence would benefit from a method to immobilize the oxidoreductase and luciferase with high specific activity. Toward this end, oxidoreductase and luciferase were fused with a segment of biotin carboxy carrier protein and produced in Escherichia coli. The in vivo biotinylated luciferase and oxidoreductase were immobilized on avidin-conjugated agarose beads with little loss of activity. Coimmobilized enzymes had eight times higher bioluminescence activity than the free enzymes at low enzyme concentration and high NADH concentration. In addition, the immobilized enzymes were more stable than the free enzymes. This immobilization method is also useful to control enzyme orientation, which could increase the efficiency of sequentially operating enzymes like the oxidoreductase-luciferase system.
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Affiliation(s)
- D J Min
- Department of Materials Science and Engineering, University of Utah, 50 S. Campus Central Drive, Room 2480, Salt Lake City, Utah, 84112-9202, USA
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33
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Abstract
The surface immobilization methods that allowed single-molecule motility experiments with native kinesin have not worked with the ncd motor protein and other kinesin-related motors. To solve this problem, a surfactant (Pluronic F108) was chemically modified with the metal-chelating group nitrilotriacetic acid (NTA) to allow surface immobilization of histidine-tagged microtubule motors. The chelating surfactant provided a convenient and effective method for immobilization and subsequent motility experiments with a dimeric H-tagged ncd protein (H-N195). In experiments with the absorption of H-N195 to polystyrene (PS) beads coated with F108-NTA, a monolayer of H-N195 bound in the presence of Ni2+, while in the absence of Ni2+, the extent of adsorption of H-N195 to PS beads was greatly reduced. In motility experiments with H-N195 immobilized on F108-NTA-coated surfaces, microtubules moved smoothly and consistently at an average speed of 0.16 +/- 0.01 micrometer/s in the presence of Ni2+, while without Ni2+, no microtubules landed on the F108-NTA-coated surfaces. Investigation of H-N195 motility on the F108-NTA surfaces provided several indications that ncd, unlike kinesin, is not processive. First, a critical H-N195 surface density for microtubule motility of approximately 250 molecules/micrometer(2) was observed. Second, microtubule landing rates as a function of H-N195 surface density in the presence of MgATP suggested that several H-N195 molecules must cooperate in microtubule landing. Third, the ATP KM in motility assays (235 microM) was substantially higher than the ATP KM of dimeric ncd in solution (23 microM) [Foster, K. A., Correia, J. J., and Gilbert, S. P. (1998) J. Biol. Chem. 273, 35307-35318].
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Affiliation(s)
- M J deCastro
- Department of Bioengineering, University of Utah, Salt Lake City 84112, USA
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34
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Abstract
An abnormality in basement membrane metabolism has been postulated to play an important role in the pathogenesis of experimental murine AA amyloidosis. The potential contribution of the structural basement membrane proteins laminin, type IV collagen and entactin to amyloidogenesis in this model was investigated with a kinetic analysis of the expression of the corresponding genes during amyloid formation. Splenic AA amyloid deposition was stimulated by the concomitant administration of subcutaneous silver nitrate, as an inflammatory stimulus, and intravenous amyloid enhancing factor. Using a reverse transcription-polymerase chain reaction assay, a differential pattern of expression of these genes was observed at the mRNA level. Whereas laminin B1 mRNA levels did not change at any time during amyloidogenesis, a 2.2 to 3 fold induction of laminin B2, entactin and alpha 1-type IV collagen mRNAs coincided with the initial detection of splenic amyloid deposits at 48 hours post-stimulation, as detected by immunohistochemistry. Temporal and spatial codeposition of laminin and type IV collagen with amyloid was demonstrated by immunohistochemistry. A 1.4, 2.3 and 2.2-fold increase in laminin B2, entactin and alpha 1-type IV collagen mRNA levels, respectively, was detected at 24 hours post-stimulation, a point at which amyloid deposits could not be detected. Neither inflammation nor amyloid enhancing factor alone influenced laminin, entactin or type IV collagen expression at the protein or mRNA level. These observations suggest that the laminin B2 chain and alpha 1-type IV collagen chain account, at least in part, for the observed laminin and collagen IV immunoreactivity in AA amyloid deposits and that entactin may also be a component of the amyloid deposit. The onset of the induction of laminin B2, entactin and alpha 1-type IV collagen gene expression prior to the appearance of amyloid deposits, and our previous data with the heparan sulfate proteoglycan, perlecan, suggests these basement membrane proteins may play a role in the initial stages of AA fibrillogenesis.
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Affiliation(s)
- S I Woodrow
- Department of Biochemistry, Queen's University Kingston, Ontario, Canada
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35
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Abstract
Stimuli-sensitive polymer hydrogels, which swell or shrink in response to changes in the environmental conditions, have been extensively investigated and used as 'smart' biomaterials and drug-delivery systems. Most of these responsive hydrogels are prepared from a limited number of synthetic polymers and their derivatives, such as copolymers of (meth)acrylic acid, acrylamide and N-isopropyl acrylamide. Water-soluble synthetic polymers have also been crosslinked with molecules of biological origin, such as oligopeptides and oligodeoxyribonucleotides, or with intact native proteins. Very often there are several factors influencing the relationship between structure and properties in these systems, making it difficult to engineer hydrogels with specified responses to particular stimuli. Here we report a hybrid hydrogel system assembled from water-soluble synthetic polymers and a well-defined protein-folding motif, the coiled coil. These hydrogels undergo temperature-induced collapse owing to the cooperative conformational transition of the coiled-coil protein domain. This system shows that well-characterized water-soluble synthetic polymers can be combined with well-defined folding motifs of proteins in hydrogels with engineered volume-change properties.
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Affiliation(s)
- C Wang
- Department of Bioengineering, University of Utah, Salt Lake City 84112, USA
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Stewart RJ, Campbell JR, Janzen ED, McKinnon J. The effects of Tritrichomonas foetus and nutritional status on the fertility of cows on a community pasture in Saskatchewan. Can Vet J 1998; 39:638-41. [PMID: 9789675 PMCID: PMC1539459] [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: 02/09/2023]
Abstract
A prospective observational study of a breeding season in a Saskatchewan community pasture was carried out to determine the cause or causes of a chronic infertility problem. There were 774 cows, from 27 herds, divided into 4 breeding groups (A,B,C,D) on the pasture. Cows entering the pasture in May were weighed, had their body condition scored and height measured. All bulls received breeding soundness examinations and a preputial wash, which was cultured for Tritrichomonas foetus and Campylobacter foetus subsp. venerealis. In July, cows were also weighed and had their body condition scored and again when they left the pasture. In addition, cows were pregnancy checked when they left the pasture. Bulls were tested again for Tritrichomonas foetus at the end of the grazing season. Two breeding groups had T. foetus-positive bulls and an average pregnancy of 84%, which was significantly lower than that of the two T. foetus negative groups (93.5%) (P = 0.0001). A cow was 2.97 times less likely to be pregnant if she had been exposed to T. foetus-positive bulls. Cows with average daily gains above the mean for the pasture were 2.12 times more likely to be pregnant. Body condition score upon entering and leaving the pasture, height, age, and breeding group were significant predictors of average daily gain.
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Affiliation(s)
- R J Stewart
- Department of Herd Medicine and Theriogenology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon
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Stewart RJ. White matter abnormalities and memory in Alzheimer's disease. Br J Psychiatry 1998; 173:269-70. [PMID: 9926110 DOI: 10.1017/s0007125000261266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
Evidence is presented that the kinesin-related ncd protein is not as processive as kinesin. In low surface density motility experiments, a dimeric ncd fusion protein behaved mechanistically more similar to non-processive myosins than to the highly processive kinesin. First, there was a critical microtubule length for motility; only microtubules longer than this critical length moved in low density ncd surfaces, which suggested that multiple ncd proteins must cooperate to move microtubules in the surface assay. Under similar conditions, native kinesin demonstrated no critical microtubule length, consistent with the behavior of a highly processive motor. Second, addition of methylcellulose to decrease microtubule diffusion decreased the critical microtubule length for motility. Also, the rates of microtubule motility were microtubule length dependent in methylcellulose; short microtubules, that interacted with fewer ncd proteins, moved more slowly than long microtubules that interacted with more ncd proteins. In contrast, short microtubules, that interacted with one or a few kinesin proteins, moved on average slightly faster than long microtubules that interacted with multiple kinesins. We conclude that a degree of processivity as high as that of kinesin, where a single dimer can move over distances on the order of one micrometer, may not be a general mechanistic feature of the kinesin superfamily.
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Affiliation(s)
- R J Stewart
- Department of Bioengineering, University of Utah, Salt Lake City 84112, USA.
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Stewart RJ, Fredenburgh JC, Weitz JI. Characterization of the interactions of plasminogen and tissue and vampire bat plasminogen activators with fibrinogen, fibrin, and the complex of D-dimer noncovalently linked to fragment E. J Biol Chem 1998; 273:18292-9. [PMID: 9660794 DOI: 10.1074/jbc.273.29.18292] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [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: 11/06/2022] Open
Abstract
Vampire bat plasminogen activator (b-PA) causes less fibrinogen (Fg) consumption than tissue-type plasminogen activator (t-PA). Herein, we demonstrate that this occurs because the complex of D-dimer noncovalently linked to fragment E ((DD)E), the most abundant degradation product of cross-linked fibrin, as well as Fg, stimulate plasminogen (Pg) activation by t-PA more than b-PA. To explain these findings, we characterized the interactions of t-PA, b-PA, Lys-Pg, and Glu-Pg with Fg and (DD)E using right angle light scattering spectroscopy. In addition, interactions with fibrin were determined by clotting Fg in the presence of various amounts of t-PA, b-PA, Lys-Pg, or Glu-Pg and quantifying unbound material in the supernatant after centrifugation. Glu-Pg and Lys-Pg bind fibrin with Kd values of 13 and 0.13 microM, respectively. t-PA binds fibrin through two classes of sites with Kd values of 0.05 and 2.6 microM, respectively. The second kringle (K2) of t-PA mediates the low affinity binding that is eliminated with epsilon-amino-n-caproic acid. In contrast, b-PA binds fibrin through a single kringle-independent site with a Kd of 0.15 microM. t-PA competes with b-PA for fibrin binding, indicating that both activators share the same finger-dependent site on fibrin. Glu-Pg binds (DD)E with a Kd of 5.4 microM. Lys-Pg binds to (DD)E and Fg with Kd values of 0.03 and 0.23 microM, respectively. t-PA binds to (DD)E and Fg with Kd values of 0.02 and 0.76 microM, respectively; interactions were eliminated with epsilon-amino-n-caproic acid, consistent with K2-dependent binding. Because it lacks a K2-domain, b-PA does not bind to either (DD)E or Fg, thereby explaining why b-PA is more fibrin-specific than t-PA.
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Affiliation(s)
- R J Stewart
- Hamilton Civic Hospitals Research Centre and McMaster University, Hamilton, Ontario, L8V 1C3 Canada
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Hrmova M, MacGregor EA, Biely P, Stewart RJ, Fincher GB. Substrate binding and catalytic mechanism of a barley beta-D-Glucosidase/(1,4)-beta-D-glucan exohydrolase. J Biol Chem 1998; 273:11134-43. [PMID: 9556600 DOI: 10.1074/jbc.273.18.11134] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.1] [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: 11/06/2022] Open
Abstract
A beta-glucosidase, designated isoenzyme betaII, from germinated barley (Hordeum vulgare L.) hydrolyzes aryl-beta-glucosides and shares a high level of amino acid sequence similarity with beta-glucosidases of diverse origin. It releases glucose from the non-reducing termini of cellodextrins with catalytic efficiency factors, kcat/Km, that increase approximately 9-fold as the degree of polymerization of these substrates increases from 2 to 6. Thus, the enzyme has a specificity and action pattern characteristic of both beta-glucosidases (EC 3.2.1.21) and the polysaccharide exohydrolase, (1,4)-beta-glucan glucohydrolase (EC 3.2.1.74). At high concentrations (100 mM) of 4-nitrophenyl beta-glucoside, beta-glucosidase isoenzyme betaII catalyzes glycosyl transfer reactions, which generate 4-nitrophenyl-beta-laminaribioside, -cellobioside, and -gentiobioside. Subsite mapping with cellooligosaccharides indicates that the barley beta-glucosidase isoenzyme betaII has six substrate-binding subsites, each of which binds an individual beta-glucosyl residue. Amino acid residues Glu181 and Glu391 are identified as the probable catalytic acid and catalytic nucleophile, respectively. The enzyme is a family 1 glycoside hydrolase that is likely to adopt a (beta/alpha)8 barrel fold and in which the catalytic amino acid residues appear to be located at the bottom of a funnel-shaped pocket in the enzyme.
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Affiliation(s)
- M Hrmova
- Department of Plant Science, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia
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Cheung AH, Stewart RJ, Marsden PA. Endothelial Tie2/Tek ligands angiopoietin-1 (ANGPT1) and angiopoietin-2 (ANGPT2): regional localization of the human genes to 8q22.3-q23 and 8p23. Genomics 1998; 48:389-91. [PMID: 9545648 DOI: 10.1006/geno.1997.5207] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- A H Cheung
- Renal Division, St. Michael's Hospital, Toronto, Ontario, Canada
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Abstract
A technique for detecting the displacement of micron-sized optically trapped probes using far-field interference is introduced, theoretically explained, and used to study the motility of the ncd motor protein. Bead motions in the focal plane relative to the optical trap were detected by measuring laser intensity shifts in the back-focal plane of the microscope condenser by projection on a quadrant diode. This detection method is two-dimensional, largely independent of the position of the trap in the field of view and has approximately 10-micros time resolution. The high resolution makes it possible to apply spectral analysis to measure dynamic parameters such as local viscosity and attachment compliance. A simple quantitative theory for back-focal-plane detection was derived that shows that the laser intensity shifts are caused primarily by a far-field interference effect. The theory predicts the detector response to bead displacement, without adjustable parameters, with good accuracy. To demonstrate the potential of the method, the ATP-dependent motility of ncd, a kinesin-related motor protein, was observed with an in vitro bead assay. A fusion protein consisting of truncated ncd (amino acids 195-685) fused with glutathione-S-transferase was adsorbed to silica beads, and the axial and lateral motions of the beads along the microtubule surface were observed with high spatial and temporal resolution. The average axial velocity of the ncd-coated beads was 230 +/- 30 nm/s (average +/- SD). Spectral analysis of bead motion showed the increase in viscous drag near the surface; we also found that any elastic constraints of the moving motors are much smaller than the constraints due to binding in the presence of the nonhydrolyzable nucleotide adenylylimidodiphosphate.
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Affiliation(s)
- M W Allersma
- Department of Physics, University of Michigan, Ann Arbor 48109, USA
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Playfor SD, Smyth AR, Stewart RJ. Increase in incidence of childhood empyema. Thorax 1997; 52:932. [PMID: 9404386] [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: 02/05/2023]
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Pereira AJ, Dalby B, Stewart RJ, Doxsey SJ, Goldstein LS. Mitochondrial association of a plus end-directed microtubule motor expressed during mitosis in Drosophila. J Cell Biol 1997; 136:1081-90. [PMID: 9060472 PMCID: PMC2132485 DOI: 10.1083/jcb.136.5.1081] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/1996] [Revised: 11/12/1996] [Indexed: 02/03/2023] Open
Abstract
The kinesin superfamily is a large group of proteins (kinesin-like proteins [KLPs]) that share sequence similarity with the microtubule (MT) motor kinesin. Several members of this superfamily have been implicated in various stages of mitosis and meiosis. Here we report our studies on KLP67A of Drosophila. DNA sequence analysis of KLP67A predicts an MT motor protein with an amino-terminal motor domain. To prove this directly, KLP67A expressed in Escherichia coli was shown in an in vitro motility assay to move MTs in the plus direction. We also report expression analyses at both the mRNA and protein level, which implicate KLP67A in the localization of mitochondria in undifferentiated cell types. In situ hybridization studies of the KLP67A mRNA during embryogenesis and larval central nervous system development indicate a proliferation-specific expression pattern. Furthermore, when affinity-purified anti-KLP67A antisera are used to stain blastoderm embryos, mitochondria in the region of the spindle asters are labeled. These data suggest that KLP67A is a mitotic motor of Drosophila that may have the unique role of positioning mitochondria near the spindle.
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Affiliation(s)
- A J Pereira
- Program in Molecular Medicine, University of Massachusetts Medical Center, Worcester 01605, USA
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Abstract
Firefly luciferase (Photinus pyralis) was fused with a histidine tag and a biotin carboxyl carrier protein (BCCP) domain at its amino terminus. Highly purified recombinant luciferase was obtained by a one-step purification protocol, utilizing immobilized metal affinity chromatography. The novel BCCP-luciferase had properties, stability, and activity similar to those of native luciferase. The biotin molecule on the BCCP domain allowed specific immobilization of BCCP-luciferase on avidin-coated surfaces via the biotin-avidin interaction.
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Affiliation(s)
- C Y Wang
- Department of Bioengineering, University of Utah, 2480 MEB, Salt Lake City, Utah, 84112, USA
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Abstract
The authors report a case of colonic duplication associated with urogenital abnormalities, which presented after obstruction of its proximal communication with the intestine. The case is unusual because the proximal communication was via a partial duplication of the appendix, which became obstructed after impaction of a fecolith.
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Affiliation(s)
- S A McNeill
- Department of Paediatric Surgery, Queen's Medical Centre, Nottingham, England
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Abstract
Wandering spleen is a rare condition that commonly presents with splenic infarction secondary to torsion. Splenectomy was previously advocated as the treatment of choice, though recent reports suggest that the organ may be distorted, and splenopexy performed. This paper documents how the latter procedure may be done using adherent omentum.
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Stewart RJ, Kashour TS, Marsden PA. Vascular endothelial platelet endothelial adhesion molecule-1 (PECAM-1) expression is decreased by TNF-alpha and IFN-gamma. Evidence for cytokine-induced destabilization of messenger ribonucleic acid transcripts in bovine endothelial cells. The Journal of Immunology 1996. [DOI: 10.4049/jimmunol.156.3.1221] [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] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Platelet endothelial cell-adhesion molecule-1 (PECAM-1, CD31) is constitutively expressed by vascular endothelium and concentrates at intercellular junctions. Regulation of PECAM-1 expression on endothelial cells may modulate leukocyte trafficking, angiogenesis, and vascular permeability. Given that cytokine activation induces profound alterations in endothelial phenotype, studies sought to determine whether cytokine treatment modulated PECAM-1 mRNA and protein content in macro- and microvascular endothelial cells. Northern blot analysis revealed expression of PECAM-1 mRNA transcripts in endothelial cells derived from bovine aorta, bovine glomeruli, and human umbilical vein under basal conditions. Treatment of endothelial cells with TNF-alpha and/or IFN-gamma led to dramatic decreases in steady-state levels of PECAM-1 mRNA transcripts. In contrast, reciprocal induction of ICAM-1 mRNA was evident. Actinomycin D chase experiments demonstrated that cytokines selectively destabilize PECAM-1 mRNA transcripts in bovine endothelial cells, decreasing the PECAM-1 mRNA transcript t1/2 from basal values of 15 +/- 2 h to 4 +/- 1 h in TNF-alpha- and IFN-gamma-treated cells (p < 0.005), an effect that appeared to be independent of new protein synthesis. Nuclear run-off analysis demonstrated no change in the rates of PECAM-1 gene transcription in response to cytokines treatment. Immunoblots and quantitative indirect immunofluorescence indicated decreased total cellular and cell-surface PECAM-1 protein expression following cytokine treatment. These findings provide evidence for cytokine-induced reciprocal regulation of transcripts of Ig-like adhesion molecules on vascular endothelium.
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Affiliation(s)
- R J Stewart
- Department of Medicine, St. Michael's Hospital, Toronto, Ontario, Canada
| | - T S Kashour
- Department of Medicine, St. Michael's Hospital, Toronto, Ontario, Canada
| | - P A Marsden
- Department of Medicine, St. Michael's Hospital, Toronto, Ontario, Canada
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