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Behar H, Mottiar Y, Chandrasekhar R, Grappadelli AC, Pauly M, Samuels AL, Mansfield SD, Brumer H. Populus endo-glucanase 16 localizes to the cell walls of developing tissues. Plant Direct 2023; 7:e482. [PMID: 36733272 PMCID: PMC9887094 DOI: 10.1002/pld3.482] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 06/18/2023]
Abstract
The hemicelluloses comprise a group of matrix glycans that interact with cellulose microfibrils in plant cell walls and play important roles in establishing wall architecture. The structures of hemicelluloses are determined by carbohydrate-active enzymes (CAZymes) that synthesize, integrate, and break down these polymers. Specifically, endo-glucanase 16 (EG16) enzymes, which are related to the well-known xyloglucan endotransglycosylase/hydrolase (XTH) gene products in Glycoside Hydrolase Family 16 (GH16), have been implicated in the degradation of the β(1,4)-linked backbone of mixed-linkage β(1,3);β(1,4)-glucans (MLG) and xyloglucans. EG16 members are single-copy genes found in most plant clades but are absent from many eudicots, including the model plant Arabidopsis thaliana. Until recently, EG16 members had only been characterized in vitro, establishing their substrate specificity, protein structure, and phylogenetic history, but their biological function was unknown. Here we used a hybrid polar, Populus alba × Populus grandidentata (P39), as a model to examine EG16 expression, subcellular localization, and pheno- and chemotypes of EG16-downregulated P39 plants. Populus EG16 expression is strong in young tissues, but RNAi-mediated downregulation did not impact plant growth nor the fine structure of the hemicellulose xyloglucan, suggesting a restricted or currently unknown role in angiosperm physiology.
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Affiliation(s)
- Hila Behar
- Michael Smith LaboratoriesUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of Biochemistry and Molecular BiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Yaseen Mottiar
- Department of Wood ScienceUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Rohan Chandrasekhar
- Department of Wood ScienceUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | | | - Markus Pauly
- Institute for Plant Cell Biology and BiotechnologyHeinrich Heine UniversityDüsseldorfGermany
| | - A. Lacey Samuels
- Department of BotanyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Shawn D. Mansfield
- Department of Wood ScienceUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of BotanyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Harry Brumer
- Michael Smith LaboratoriesUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of Biochemistry and Molecular BiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of BotanyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of ChemistryUniversity of British ColumbiaVancouverBritish ColumbiaCanada
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Kaul S, Alladi S, Mridula KR, Bandaru VCSS, Umamashesh M, Anjanikumar D, Lalitha P, Chandrasekhar R. Prevalence and risk factors of asymptomatic carotid artery stenosis in Indian population: An 8-year follow-up study. Neurol India 2019; 65:279-285. [PMID: 28290390 DOI: 10.4103/neuroindia.ni_523_16] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Asymptomatic carotid artery stenosis (ACAS) is a marker for cerebrovascular disease, coronary atherosclerosis, and death. AIM To investigate the prevalence of ACAS in the Indian population, and to correlate ACAS with other vascular risk factors. MATERIALS AND METHODS We prospectively recruited 1500 individuals who were older than 40 years and asymptomatic for cerebrovascular disease between June 2003 and December 2014. Evaluation of vascular risk factors was done for all the participants. Color Doppler of bilateral carotid arteries was performed for all the participants. Carotid stenosis of 1-49% and ≥50% was considered to be mild and significant stenosis, respectively. RESULTS There were 1016 (67.7%) men, with a mean age of 58.1 ± 10.6 years (age range: 40-98 years). The prevalence of significant carotid stenosis was 5.2%. After adjustment using multiple regression analysis, age >70 years (OR: 2.0; 95% CI: 1.48-2.74), hypertension (OR: 1.8; 95% CI: 1.11-2.96), diabetes (OR: 2.3; 95%CI: 1.45-3.89), smoking (OR: 3.6; 95% CI: 2.18-6.03), dyslipidemia (OR: 4.0; 95% CI: 2.52-6.63), history of migraine (OR: 3.6; 95% CI: 2.54-9.13), history of periodontitis (OR: 3.2; 95% CI: 1.90-5.68), and family history of stroke (OR: 7.1; 95% CI: 4.20-12.2) were significantly associated with >50% stenosis. Duration (>15 years) of hypertension (OR: 2.5; 95% CI: 1.33-6.43), diabetes (OR: 6.2; 95% CI: 3.41-11.3), and smoking (OR: 5.2; 95% CI: 2.20-12.1) markedly worsened the risk. During the 8-year follow up, 14 participants (1.4%) with mild stenosis and 3 participants (4.7%) with significant stenosis developed stroke. CONCLUSIONS Our study suggests that 5.2% of asymptomatic individuals > 40 years of age harbor significant extracranial carotid artery disease. Presence of multiple vascular risk factors markedly increases the risk of carotid stenosis.
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Affiliation(s)
- Subhash Kaul
- Department of Neurology, Nizam's Institution of Medical Sciences, Hyderabad, Telangana, India
| | - Suvarna Alladi
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | - K Rukmini Mridula
- Department of Neurology, Nizam's Institution of Medical Sciences, Hyderabad, Telangana, India
| | | | | | | | - Palli Lalitha
- Department of Radiology, Yashoda Hospital, Hyderabad, Telangana, India
| | - R Chandrasekhar
- Department of Radiology, Yashoda Hospital, Hyderabad, Telangana, India
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Sandeep V, Kumar M, Vinay C, Chandrasekhar R, Jyostna P. Oral health status and treatment needs of hearing impaired children attending a special school in Bhimavaram, India. Indian J Dent Res 2017; 27:73-7. [PMID: 27054865 DOI: 10.4103/0970-9290.179835] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Children with hearing impairment (CHI) have special accessibility issues to meet their health care needs. Their oral health status is deprived and has wide ranging treatment needs to attend. AIM The aim of this study was to evaluate the oral health status and treatment needs of CHI attending a special school in Bhimavaram Town, India. STUDY DESIGN The study design was a descriptive cross-sectional study. MATERIALS AND METHODS This study was conducted in November 2012 at SVS special school for deaf, Bhimavaram, India. This study involved 180 CHI of both genders, aged 6-16 years, divided into Group-I (6-8 years), Group-II (9-12 years), and Group-III (13-16 years). Oral health status and treatment needs were recorded using methods and standards recommended by the WHO for Oral Health Surveys, 1997. Dental caries prevalence (decayed, missing, and filled teeth [DMFT/dmft]), gingivitis levels (Lφe, Silness Gingival Index), plaque levels (Silness, Lφe Plaque index), and treatment needs were the parameters recorded and analyzed. STATISTICAL ANALYSIS Z-test for proportion, one-way analysis of variance, and Chi-square test were used to analyze the data. RESULTS Prevalence of dental caries in the sample was found to be 65% with a mean level of caries prevalence (DMFT) of 1.6 ± 1.3 in Group-I, 1.9 ± 1.2 in Group-II, and 2.2 ± 1.2 in Group-III. About 91.7% of the total children examined needs treatment. The mean plaque and gingivitis scores of the sample were 1.70 ± 0.61 and 1.59 ± 0.58, respectively. CONCLUSION These findings imply the overwhelming situation of CHI in oral health perspective. Hence, prevention-based educational and motivational programs should be targeted to this vital group to achieve adequate oral hygiene levels.
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Affiliation(s)
- V Sandeep
- Department of Pediatric Dentistry, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India
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Abstract
The present report describes a case of Noonan's syndrome from a dental viewpoint. Noonan syndrome is an autosomal dominant multisystem disorder. Congenital heart deformities, short stature, thoracic deformities, short neck with webbing, hypertelorism, and malocclusions are some of the frequently observed clinical features. Atypical dental anomalies such as multiple unerupted permanent teeth, multiple submerged and retained deciduous teeth, and supernumerary teeth were found in the present case. Oral prophylaxis and preventive resin restorations were done following which the supernumerary teeth were extracted. 54, 55, 64, 65, 74, 75 and 84 were extracted after orthodontic consultation to facilitate the eruption of permanent teeth. The patient is undergoing fixed orthodontic therapy for forced eruption of unerupted permanent teeth. General dentists should correlate dental anomalies with other systemic features in the diagnosis of such syndromes because of the variability in presentation and the need for multidisciplinary care.
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Affiliation(s)
- KS Uloopi
- Department of Pedodontics and Preventive Dentistry, Vishnu Dental College, Bhimavaram, West Godavari, Andhra Pradesh, India
| | - V Madhuri
- Department of Pedodontics and Preventive Dentistry, Vishnu Dental College, Bhimavaram, West Godavari, Andhra Pradesh, India
| | - AS Gopal
- Department of Pedodontics and Preventive Dentistry, Vishnu Dental College, Bhimavaram, West Godavari, Andhra Pradesh, India
| | - C Vinay
- Department of Pedodontics and Preventive Dentistry, Vishnu Dental College, Bhimavaram, West Godavari, Andhra Pradesh, India
| | - R Chandrasekhar
- Department of Pedodontics and Preventive Dentistry, Vishnu Dental College, Bhimavaram, West Godavari, Andhra Pradesh, India
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Uloopi KS, Shivaji RU, Vinay C, Shrutha SP, Chandrasekhar R. Conservative management of large radicular cysts associated with non-vital primary teeth: a case series and literature review. J Indian Soc Pedod Prev Dent 2015; 33:53-6. [PMID: 25572375 DOI: 10.4103/0970-4388.149007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [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: 11/04/2022] Open
Abstract
Radicular cysts are the most common odontogenic cystic lesions of inflammatory origin. Large radicular cyst is comparatively less frequently associated with primary teeth. They represent only 0.5-3.3% of the total number of cysts in primary dentition. Radicular cysts arising from deciduous teeth are reported to occur in age range of 3-19 years with a male predominance. Although large radicular cysts are treated by enucleation with extensive removal of bone and vital teeth, marsupialization can be preferred as a conservative approach to reduce the morbidity. The purpose of this article is to report a case series of large radicular cysts associated with badly mutilated and traumatized primary teeth and to demonstrate how best they can be conservatively treated during mixed dentition period.
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Affiliation(s)
- K S Uloopi
- Department of Pediatric Dentistry, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India
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Patel M, Jackson J, Morandi A, Girard T, Hughes C, Kiehl A, Thompson J, Chandrasekhar R, Ely E, Pandharipande P. Post-traumatic stress disorder prevalence and subtypes among survivors of critical illness. Crit Care 2015. [PMCID: PMC4471303 DOI: 10.1186/cc14635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Boyd S, Upender R, Walters A, Chandrasekhar R, Wang L. Validation of the ET-AHI: Effectiveness of Obstructive Sleep Apnea Treatment Index. J Oral Maxillofac Surg 2014. [DOI: 10.1016/j.joms.2014.06.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Kane I, Abramo T, Crossman K, Meredith M, Estrada C, Chandrasekhar R, Wang W. Cerebral SO 2 Monitoring in Pediatric Altered Mental Status Patients. Ann Emerg Med 2013. [DOI: 10.1016/j.annemergmed.2013.07.298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Malik N, Chandrasekhar R, Salerno May K, Ma W, Flaherty L, Iyer R, Kuvshinoff B, Gibbs J, Wilding G, Yang G. Chemoradiotherapy vs. Chemotherapy Alone in Patients with Locally Advanced Unresectable Pancreatic Carcinoma: A 10-year Experience. Int J Radiat Oncol Biol Phys 2010. [DOI: 10.1016/j.ijrobp.2010.07.739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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10
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Yang G, Malik N, Chandrasekhar R, Salerno May K, Watroba N, Flaherty L, Ma W, Kuvshinoff B, Wilding G, Gibbs J. Change in CA 19-9 Levels after Chemoradiotherapy Predicts Survival in Patients with Locally Advanced Unresectable Pancreatic Cancer. Int J Radiat Oncol Biol Phys 2010. [DOI: 10.1016/j.ijrobp.2010.07.709] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Yang G, Khushalani N, Chandrasekhar R, Wilding G, McCloskey S, Flaherty L, Yap J, Gibbs J, Fakih M, Salerno May K. Renal Atrophy Secondary to Abdominal Chemoradiotherapy: Receiver Operating Characteristic (ROC) Analysis. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Salerno May K, Fakih M, Khushalani N, Chandrasekhar R, Wilding G, Park L, Flaherty L, Russo R, Iyer R, Yang G. Renal Function following Abdominal Chemoradiotherapy for Gastrointestinal Malignancies in Elderly Patients. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Yuh B, Chandrasekhar R, Hussain A, Wilding G, Mohler J, Menon M, Peabody J, Guru K. MP-05.14: Robotics in Urology: Comparison of International Practice Patterns. Urology 2009. [DOI: 10.1016/j.urology.2009.07.1017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Salerrno May KS, Yang GY, Iyer RV, Chandrasekhar R, Wilding G, Khushalani NI, Yendamuri SS, Gibbs JF, Fakih M. Renal atrophy secondary to chemoradiation treatment of abdominal malignancies. J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.e15532] [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: 11/20/2022] Open
Abstract
e15532 Background: Information on renal atrophy following abdominal chemoradiation (CRT) is limited. Methods: Patients who received concurrent CRT to the abdomen between 2002 and 2008 were identified for this study to evaluate change in renal size (RS) and function following CRT. Imaging and biochemical data were obtained prior to radiation (RT) and after RT in 6 month intervals. RS was defined by craniocaudal measurement on CT images. Renal function was assessed by serum creatinine and creatinine clearance (CrCl) using the Cockcroft-Gault formula. The primarily irradiated kidney (PK) was defined as the kidney that received the greater mean kidney dose. Results: Median patient age was 64 years (range 31–87), 51.5% of 130 patients were male. Primary disease sites were pancreas (61.5%), periampullary (16.1%), stomach (10.8%), gastroesophageal junction (10%), and retroperitoneum (1.5%). Median follow up was 9.4 months (range 0–55.4 mos). Median radiation dose was 50.4Gy (range 12.6- 55.8Gy). Mean dose to the PK was 18.6 Gy. Compensatory hypertrophy of the non-PK was not seen. Age, gender, hypertension, diabetes, smoking, pre-RT CrCl, and pre-RT RS were not associated with renal atrophy at 12 months post RT. Percent volumes of the PK receiving ≥10Gy (V10), 15Gy (V15), and 20Gy (V20) were significantly associated with renal atrophy at 12 months post RT (p=0.0030, 0.0041, and 0.0046 respectively). Conclusions: Significant detriments in PK size and renal function were seen following abdominal CRT. V10, V15, and V20 were associated with renal atrophy at 12 months post RT. These observations can assist with renal dose constraints in CRT treatment planning for patients at increased risk for renal complications. [Table: see text] No significant financial relationships to disclose.
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Affiliation(s)
| | - G. Y. Yang
- Roswell Park Cancer Institute, Buffalo, NY
| | - R. V. Iyer
- Roswell Park Cancer Institute, Buffalo, NY
| | | | - G. Wilding
- Roswell Park Cancer Institute, Buffalo, NY
| | | | | | | | - M. Fakih
- Roswell Park Cancer Institute, Buffalo, NY
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Yang G, Parikh K, Flaherty L, Chandrasekhar R, Wilding G, Russo R, Fakih M, Kuvshinoff B, Gibbs J, Javle M. Renal Function after Radiotherapy to the Abdomen. Int J Radiat Oncol Biol Phys 2008. [DOI: 10.1016/j.ijrobp.2008.06.1724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Yang G, Flaherty L, Wagner T, Yap J, Chandrasekhar R, Wilding G, Khushalani N, Iyer R, Lamonica D, Thomas C. Subclinical Impairment of Renal Function Following Abdominal Radiotherapy: An Analysis using Specific Scintigraphic and Biochemical Endpoints. Int J Radiat Oncol Biol Phys 2008. [DOI: 10.1016/j.ijrobp.2008.06.1413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Raman AK, Lombardo JC, Chandrasekhar R, Fakih MG. Bevacizumab (BV) related adverse events among various age groups of elderly patients with advanced colorectal cancer. J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.14546] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
14546 Background: Hypertension (HTN), arterial thrombosis (ATE), venous thrombosis (VTE), and gastrointestinal perforation (P) are known BV related adverse events. The incidence of these events in different age groups of elderly patients (= 65 years) has not been well described. This study aimed at identifying the incidence of HTN, ATE, VTE, and P among three age groups: 65–69, 70–74 and =75 years. Methods: A retrospective chart review of CRC patients = 65 yrs treated with BV based chemotherapy during the period of January 2004 - July 2006 at Roswell Park Cancer Institute was performed. The incidence of grade (G) 3–4 HTN, ATE, VTE, and P was calculated. Results: Sixty patients = 65 yrs received BV during the study period: 20 patients were 65–69, 19 were 70–74, and 21 were = 75 years of age. The median age was 73 (range 65–90). Eight (13.3%) patients developed G3–4 arterial thromboembolic events, 7 (11.6%) developed G3–4 venous thromboembolic events, 10 (16.6%) developed G3 HTN, and 2 (3.3%) had a bowel perforation. The incidence of ATE was the highest in the = 75 age group (4/21, 19%) when compared to the 70–74 age group (2/19, 11%) and the 65–69 age group (2/20, 10%). Similarly, G3 HTN was more common in the = 75 years age group (6/21, 29%) when comparison to the 70–74 (2/19, 11%) and the 65–69 (2/20, 10%) age groups. VTE were evenly distributed in all 3 age groups while one P occurred in the 70–74 and = 75 age groups respectively. The trend of increasing incidence of ATE and HTN did not reach statistical significance using Odds Ratio analysis (SAS exact logistic regression method), likely due to the small sample size. Conclusion: The incidence of ATE and HTN is increased in the elderly population, especially in patients = 75 yrs. BV based therapy needs to be investigated further in this population to determine if BV clinical benefits outweigh the associated risks. No significant financial relationships to disclose.
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Affiliation(s)
- A. K. Raman
- University at Buffalo, Buffalo, NY; Roswell Park Cancer Institute, Buffalo, NY
| | - J. C. Lombardo
- University at Buffalo, Buffalo, NY; Roswell Park Cancer Institute, Buffalo, NY
| | - R. Chandrasekhar
- University at Buffalo, Buffalo, NY; Roswell Park Cancer Institute, Buffalo, NY
| | - M. G. Fakih
- University at Buffalo, Buffalo, NY; Roswell Park Cancer Institute, Buffalo, NY
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Chandrasekhar R, Ophir J, Krouskop T, Ophir K. Elastographic image quality vs. tissue motion in vivo. Ultrasound Med Biol 2006; 32:847-55. [PMID: 16785007 DOI: 10.1016/j.ultrasmedbio.2006.02.1407] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Revised: 02/06/2006] [Accepted: 02/14/2006] [Indexed: 05/10/2023]
Abstract
Elastography is a noninvasive method of imaging tissue elasticity using standard ultrasound equipment. In conventional elastography, axial strain elastograms are generated by cross-correlating pre- and postcompression digitized radio frequency (RF) echo frames acquired from the tissue before and after a small uniaxial compression, respectively. The time elapsed between the pre- and the postcompression frames is referred to as the interframe interval. For in vivo elastography, the interframe interval is critical because uncontrolled physiologic motion such as heartbeat, muscle motion, respiration and blood flow introduce interframe decorrelation that reduces the quality of elastograms. To obtain a measure of this decorrelation, in vivo experimental data (from human livers and thyroids) at various interframe intervals were obtained from 20 healthy subjects. To further examine the effect of the different interframe intervals on the elastographic image quality, the experimental data were also used in combination with elastographic simulation data. The deterioration of elastographic image quality was objectively evaluated by computing the area under the strain filter (SF) at a given resolution. The experimental results of this study demonstrate a statistical exponential behavior of the temporal decay of the echo signal cross-correlation amplitudes from the in vivo tissues due to uncontrollable motion. The results also indicate that the dynamic range and height of the SF are reduced at increased interframe intervals, suggesting that good objective image quality may be achieved provided only that a high frame rate is maintained in elastographic applications.
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Affiliation(s)
- R Chandrasekhar
- The University of Texas Medical School, Department of Radiology, Ultrasonics Laboratory, Houston, TX 77030, USA
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Brick T, Primrose B, Chandrasekhar R, Roy S, Muliyil J, Kang G. Water contamination in urban south India: household storage practices and their implications for water safety and enteric infections. Int J Hyg Environ Health 2005; 207:473-80. [PMID: 15575563 DOI: 10.1078/1438-4639-00318] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [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: 11/18/2022]
Abstract
Water contamination, at source and during household storage, is a major cause of enterically transmitted infections in developing countries. This study assessed contamination of the municipal water in a south Indian town, which obtains its water intermittently from a surface lake and by pumping subsurface water from a dry river bed, and monitored microbial contamination during household storage. All samples of the 'treated' municipal water were contaminated when freshly pumped, and on household storage, 25/37 (67%) showed increased contamination during storage periods from 1 to 9 days. Household storage in brass, but not in containers of other materials significantly decreased contamination of water (p = 0.04). This was confirmed in the laboratory by testing water seeded with 10(3) to 10(5) Escherichia coli per 100 ml stored in containers of different materials (p < 0.01). Despite the requirements for provision of safe drinking water in municipal areas, in practice the water supplied in Vellore is contaminated and current household storage practices increase the level of contamination in at least two-thirds of households. The implementation of locally appropriate point-of-use disinfection and safe household storage practices in developing countries is an urgent need to ensure a safe, reliable year-round supply in areas where clean water is not available.
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Affiliation(s)
- Thomas Brick
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India
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Chandrasekhar R, Attikiouzel Y. New range-based neighbourhood operator for extracting edge and texture information from mammograms for subsequent image segmentation and analysis. ACTA ACUST UNITED AC 2000. [DOI: 10.1049/ip-smt:20000853] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Abstract
This paper outlines a simple, fast, and accurate method for automatically locating the nipple on digitized mammograms that have been segmented to reveal the skin-air interface. If the average gradient of the intensity is computed in the direction normal to the interface and directed inside the breast, it is found that there is a sudden and distinct change in this parameter close to the nipple. A nipple in profile is located between two successive maxima of this parameter; otherwise, it is near the global maximum. Specifically, the nipple is located midway between a successive maximum and minimum of the derivative of the average intensity gradient; these being local turning points for a nipple in profile and global otherwise. The method has been tested on 24 images, including both oblique and cranio-caudal views, from two digital mammogram databases. For 23 of the images (96%), the rms error was less than 1 mm at image resolutions of 400 microns and 420 microns per pixel. Because of its simplicity, and because it is based both on the observed behavior of mammographic tissue intensities and on geometry, this method has the potential to become a generic method for locating the nipple on mammograms.
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Affiliation(s)
- R Chandrasekhar
- Department of Electrical and Electronic Engineering, University of Western Australia, Nedlands, Australia.
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Chandrasekhar R, Huang HM, Sun GY. Alterations in rat brain polyphosphoinositide metabolism due to acute ethanol administration. J Pharmacol Exp Ther 1988; 245:120-3. [PMID: 2834532] [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: 01/02/2023] Open
Abstract
The effects of acute ethanol administration on the polyphosphoinositide metabolism of rat brain cerebral cortex were examined. Intracerebral injections of [gamma-32P]ATP proved to be an effective in vivo method to prelabel brain phospholipids, especially the polyphosphoinositides. High acute doses of ethanol (8 or 6 g/kg b.wt.) administered by gavage significantly inhibited the breakdown of polyphosphoinositides as judged by an elevation in the concentration as well as the labeling of these compounds. Concomitantly, there was a significant reduction in the level of diacylglycerols. Low acute doses of ethanol (2 g/kg b.wt.) did not seem to have any effects on the basal levels or labeling of these compounds. The changes in polyphosphoinositide labeling due to ethanol intoxication were reverted to near control values when animals regained their righting reflex (approximately 4 hr). These studies demonstrate that, under normal conditions, polyphosphoinositides and diacylglycerols are maintained in a dynamic equilibrium and that acute doses of ethanol can suppress the signal transduction process and disturb this equilibrium.
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Affiliation(s)
- R Chandrasekhar
- Sinclair Comparative Medicine Research Farm, University of Missouri, Columbia
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Abstract
Alterations in brain phospholipid metabolism were observed after chronic ethanol administration for 16 days to developing rats. Animals were injected intraperitoneally with 32Pi 16 h prior to killing. Overall uptake of 32Pi by brain did not differ between the control and ethanol-treated groups, which were killed 2 h and 24 h after the last ethanol feeding. Except for an increase in the labeling of myelin after ethanol treatment, the amount of radioactivity recovered in the synaptosomal-mitochondrial and plasma membrane fractions of control and ethanol-treated groups was not different. Relative to the radioactivity of phosphatidylcholines, which indicated no change, there were increases (20-44%) in labeling of ethanolamine plasmalogens, phosphatidic acids, and phosphatidylinositols in cortical synaptosomes from the 2-h ethanol-treated group. In the plasma membrane fractions, however, increases (9-14%) in labeling of phosphatidylserines and phosphatidylinositols were observed in both 2- and 24-h ethanol-treated groups. In both membrane fractions, there was an obvious increase (44-86%) in labeling of polyphosphoinositides at 24 h after withdrawal from ethanol. Results thus indicate an adaptive increase in the biosynthesis of ethanolamine plasmalogen and brain acidic phospholipids due to chronic ethanol administration. Furthermore, the increase in labeling of polyphosphoinositides in the 24-h withdrawal group may reflect the hypoactivity associated with ethanol withdrawal.
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Chandrasekhar R. Population and economic development. Bull Gandhigram Inst Rural Health Fam Welf Trust 1981; 16:63-86. [PMID: 12266852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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