830 results on '"CHAN, K. S."'
Search Results
802. Occurrence of matrix metalloproteinases and tissue inhibitors of metalloproteinases in tuberculous pleuritis.
- Author
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Hoheisel G, Sack U, Hui DS, Huse K, Chan KS, Chan KK, Hartwig K, Schuster E, Scholz GH, and Schauer J
- Subjects
- Adult, Aged, Analysis of Variance, Case-Control Studies, Electrophoresis, Polyacrylamide Gel, Enzyme-Linked Immunosorbent Assay, Exudates and Transudates enzymology, Female, Heart Failure enzymology, Humans, Male, Matrix Metalloproteinase 1 analysis, Matrix Metalloproteinase 2 analysis, Matrix Metalloproteinase 3 analysis, Matrix Metalloproteinase 8 analysis, Matrix Metalloproteinase 9 analysis, Middle Aged, Statistics, Nonparametric, Matrix Metalloproteinases analysis, Tissue Inhibitor of Metalloproteinase-1 analysis, Tissue Inhibitor of Metalloproteinase-2 analysis, Tuberculosis, Pleural enzymology
- Abstract
Objective: Matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) have been found in high concentrations in pleural effusions. Because MMP and TIMP may play a part in the causation of the fibrosis seen in tuberculous (TB) pleuritis their occurrence was examined., Design: Pleural effusion fluid and plasma concentrations of MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, TIMP-1 and TIMP-2 were determined by ELISA in 21 patients with TB pleuritis. To adjust for the total protein content, respective ratios were calculated. Activities of MMP-2 and MMP-9 were measured by gelatine zymography and the MMP-9/MMP-2 ratios calculated. Pleural effusions and plasma of 15 patients with congestive heat failure (CHF) and plasma of 15 healthy persons (CON) served as controls., Results: Immunoreactive pleural fluid concentrations of MMP-1, MMP-2, MMP-8, and MMP-9 were higher in TB compared to CHF, but plasma concentrations were not different between the groups. TB pleural fluid concentrations of MMP-1, MMP-2, TIMP-1, and TIMP-2 were higher compared to TB plasma. MMP-3 was found in trace amounts only. The MMP-9/total protein ratios in pleural fluid were higher in TB compared to CHF (0.4492+/-0.1633 vs 0.0364+/-0.0145, P<0.005) but the TIMP-1 ratios were lower (139.0+/-28.7 vs 517.8+/-183.7, P<0.0005). In TB pleural fluid vs TB plasma, the respective MMP-1, MMP-2, TIMP-1, and TIMP-2 ratios were increased (0.46+/-0.10 vs 0.17+/-0.02; 25.2+/-2.8 vs 4.2+/-0.9; 139.0+/-28.7 vs 27.8+/-8.2; 0.67+/-0.13 vs 0.18+/-0.04, P<0.0005 each). Gelatine zymography demonstrated MMP-2 and MMP-9 bands of different brightness in TB effusions but in CHF effusions the MMP-9 band was barely visible. The MMP-9/MMP-2 effusion ratios were therefore higher in TB compared to CHF (0.46+/-0.15 vs 0.05+/-0.04, P<0.0005)., Conclusion: Compartmentalized MMP-1, MMP-2, TIMP-1, and TIMP-2 and, compared to CHF, a surplus of MMP-1, MMP-2, MMP-8, and MMP-9 in the pleural space obviously contribute to the fibrotic reactions in TB pleuritis., (Copyright 2001 Harcourt Publishers Ltd.)
- Published
- 2001
- Full Text
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803. Pattern of lymph node pathology in a private pathology laboratory.
- Author
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Kim LH, Peh SC, Chan KS, and Chai SP
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Biopsy, Child, Child, Preschool, Female, Humans, Infant, Laboratories, Lymph Node Excision, Lymph Nodes surgery, Lymphatic Metastasis, Male, Middle Aged, Pathology, Surgical, Lymph Nodes pathology, Lymphatic Diseases pathology
- Abstract
Lymph node excision biopsy is commonly carried out for the investigation of lymphadenopathy. The objective of this study is to elucidate the pattern of nodal pathology seen in a private pathology practice. A total of 137 nodal biopsies for primary investigation of nodal enlargement were retrieved from the files in a private diagnostic pathology laboratory in the year 1997. Lymph nodes excised for cancer staging were excluded from this study. The histology was reviewed based on H&E stained sections, and with additional histochemical and immunoperoxidase stains when deemed necessary. Cases of malignant lymphomas were sub-classified with the aid of further immunophenotyping using a panel of monoclonal and polyclonal lymphoid antibodies. One case was excluded from this study due to inadequate tissue for further assessment. There were 58 males and 78 females, giving a ratio of 1:1.3 in the remaining 136 cases. They consisted of 13 Malays (M), 108 Chinese (C), 14 Indians (I) and 1 other ethnic group (O). The ratio of M:C:I:O was 1:8.3:1.1:0.1. The majority of the cases were in the age range of 20 to 50 years. The pathology consisted of 17 (12.5%) malignant lymphomas [6 Hodgkin's lymphoma, 11 non-Hodgkin's lymphoma], 35 (25.7%) metastatic carcinomas, 45 (33.1%) reactive hyperplasia, 19 (13.9%) tuberculosis, 11 (8.2%) Kikuchi's disease and 9 (6.6%) others (Castleman's disease 2, cat scratch disease 2, Kimura's disease 1, sarcoidosis 1, non-specific lymphadenitis 3). All categories of nodal disease showed approximately similar ratio of ethnic and gender distribution as above, except for Kikuchi's disease, for which 100% of the patients were female. The most common site of biopsy was from the head and neck region, particularly the cervical group of nodes. The most common nodal pathology seen in the private laboratory was reactive hyperplasia, followed by metastatic carcinoma. Malignant lymphoma constituted only 12.5% of the cases.
- Published
- 1999
804. Ileal strongyloidiasis in a Malaysian patient.
- Author
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Shekhar KC, Pathmanathan R, Loo VS, and Chan KS
- Subjects
- Aged, Animals, Enteritis parasitology, Female, Gastritis parasitology, Gastrointestinal Hemorrhage parasitology, Gastrointestinal Hemorrhage surgery, Humans, Malaysia, Strongyloides stercoralis isolation & purification, Ileal Diseases complications, Ileal Diseases parasitology, Strongyloidiasis complications, Strongyloidiasis parasitology
- Published
- 1999
805. From patterns to processes: phase and density dependencies in the Canadian lynx cycle.
- Author
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Stenseth NC, Falck W, Chan KS, Bjørnstad ON, O'Donoghue M, Tong H, Boonstra R, Boutin S, Krebs CJ, and Yoccoz NG
- Subjects
- Animals, Bayes Theorem, Canada, Geography, Lagomorpha, Models, Statistical, Population Density, Carnivora, Ecosystem
- Abstract
Across the boreal forest of North America, lynx populations undergo 10-year cycles. Analysis of 21 time series from 1821 to the present demonstrates that these fluctuations are generated by nonlinear processes with regulatory delays. Trophic interactions between lynx and hares cause delayed density-dependent regulation of lynx population growth. The nonlinearity, in contrast, appears to arise from phase dependencies in hunting success by lynx through the cycle. Using a combined approach of empirical, statistical, and mathematical modeling, we highlight how shifts in trophic interactions between the lynx and the hare generate the nonlinear process primarily by shifting functional response curves during the increase and the decrease phases.
- Published
- 1998
- Full Text
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806. Phase- and density-dependent population dynamics in Norwegian lemmings: interaction between deterministic and stochastic processes.
- Author
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Stenseth NC, Chan KS, Framstad E, and Tong H
- Subjects
- Animals, Ecosystem, Models, Biological, Nonlinear Dynamics, Norway, Population Density, Population Dynamics, Stochastic Processes, Arvicolinae
- Abstract
We analysed two 26-year long (1970-1995) time-series on annual population growth rates of Norwegian lemmings (Lemmus lemmus) from Finse, south Norway, using a threshold autoregressive (TAR) approach. We demonstrate that the population dynamics is both phase- and density-dependent. The phase-dependence accounts for the observed nonlinearity. We used the deduced stochastic model structure as a basis for evaluating the dynamic properties of this system. The dynamics is characterized either by limit cycles or chaos (the latter with a strong semi-periodic component). Stochasticity is seen to play an important role in the determination of the periodicity. The ecological implications of these statistical and mathematical results are discussed.
- Published
- 1998
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807. Is the asthma quality of life questionnaire a useful measure for low-income asthmatics?
- Author
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Leidy KN, Chan KS, and Coughlin C
- Subjects
- Adult, Black or African American, Asthma physiopathology, Attitude to Health, Baltimore, Black People, Evaluation Studies as Topic, Female, Forced Expiratory Volume physiology, Georgia, Health Status Indicators, Humans, Male, Peak Expiratory Flow Rate physiology, Personal Satisfaction, Reproducibility of Results, Severity of Illness Index, Surveys and Questionnaires, White People, Asthma psychology, Poverty, Quality of Life
- Abstract
The purpose of this study was to evaluate the reliability and validity of the Asthma Quality of Life Questionnaire (AQLQ) in a population-based sample of low-income adults with asthma. A total of 112 subjects (46 African American, 66 Caucasian; mean age = 33 +/- 9 yr; 26% male) were recruited from the Baltimore County, Maryland and Atlanta, Georgia metropolitan areas. Internal consistency reliability (Cronbach's alpha) was high for the overall scale (0. 96); 2-wk reproducibility (intraclass correlation, ICC) was 0.82 (n = 38). Overall score was significantly correlated with FEV1 percentage of predicted (r = 0.20), and the Asthma Disease Severity Scale (r = -0.38). Correlations between overall score and the SF-36 Physical Component Summary (r = 0.49), SF-36 Mental Component Summary (r = 0.37), Cantril's Ladder (r = 0.23), and the Health Utilities Index (r = 0.22) supported the validity of the AQLQ in this sample. Comparison of reliability and validity estimates across racial groups found few substantive differences. Internal consistency, reproducibility, and validity estimates found in this sample were consistent with those of a reliable and valid measure and were comparable to those found in other populations. These results suggest the AQLQ is a useful indicator of health- related quality of life in low-income asthmatics.
- Published
- 1998
- Full Text
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808. The impact of asthma on health-related quality of life.
- Author
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Schmier JK, Chan KS, and Leidy NK
- Subjects
- Asthma therapy, Humans, Asthma physiopathology, Health Status, Quality of Life, Sickness Impact Profile
- Abstract
Although a substantial body of epidemiological and economic literature on asthma exists, relatively little is known about the impact of asthma on health-related quality of life (HRQL). The purpose of this review was to synthesize results from recent studies, profile the factors influencing HRQL in asthmatics, discuss the impact of treatment on HRQL outcomes, and offer recommendations for further research. The results of this review support the premise that asthma can adversely affect the physical, psychological, and social domains of HRQL. Published data suggest that females, those from lower socioeconomic groups, and ethnic minorities experience poorer quality of life as a result of their asthma symptoms. Results of published clinical trials indicate treatment regimens can have a significant impact on HRQL outcomes. Pharmacological interventions appear to effect change primarily in the physical domain and behavioral interventions lead to improvements in both physical and psychosocial domains. Future research should focus on precise a priori delineation of research hypotheses, including the selection of primary and secondary endpoints, the clarification and consistent application of criteria for defining asthma severity, thoughtful selection of HRQL instruments appropriate for the research hypotheses and target population, and careful delineation of clinically meaningful change scores of asthma-specific outcome measures.
- Published
- 1998
- Full Text
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809. A dynamic frailty model for multivariate survival data.
- Author
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Yue H and Chan KS
- Subjects
- Biometry methods, Humans, Models, Statistical, Multivariate Analysis, Research Design, Survival Analysis
- Abstract
We consider the statistical modeling of data consisting of many study subjects with serially correlated multivariate survival responses. The (ordinary) frailty model handles the serial correlation in such data by introducing an unobserved multiplicative random effect term, called the frailty, in the hazard function. The frailties are often assumed to be identical for the survival times from the same unit. We have generalized the frailty model by allowing the frailties to vary stochastically with the indices. We have proposed a simple scheme to update the dynamic frailties. This approach assumes that the random effects are gamma distributed. At each occurrence, the two gamma parameters are updated according to the past information. In terms of their marginal distributions, the dynamic frailties form a multiplicative random walk. This approach results in a tractable likelihood. The small sample behavior of the MLE is studied via a simulation experiment. The model is then illustrated with a data set from an animal carcinogenesis experiment.
- Published
- 1997
810. Conservative management of patients with histological incomplete excision of cervical intraepithelial neoplasia after large loop excision of transformation zone.
- Author
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Chan KS, Yu KM, Lok YH, Sin SY, and Tang LC
- Subjects
- Adult, Female, Follow-Up Studies, Gynecologic Surgical Procedures methods, Humans, Middle Aged, Neoplasm Recurrence, Local, Reoperation, Uterine Cervical Neoplasms surgery, Uterine Cervical Dysplasia surgery
- Abstract
Objective: To evaluate conservative management of patients with histological incomplete excision of CIN after large loop excision of transformation zone (LLETZ)., Methods: Two hundred and seventeen patients with high grade CIN were treated with LLETZ from October 1, 1992 to December 31, 1994. Fifty-three patients (24.4%) had incomplete excision on histology. All patients were followed up cytologically every 3 to 6 months during the first 18 months and then yearly till December 1996. Those patients with positive endocervical margins were followed up with both cervical smear and endocervical smear., Results: The mean follow-up duration was 30.4 months. Ten patients were found to have persistent or recurrent disease. Five patients had second LLETZ and complete excision was achieved in 4 of them, one patient had cone biopsy and two had hysterectomy. One patient was found to have stage I a cervical cancer., Conclusion: A report of incomplete excision of CIN after LLETZ calls for follow-up with cytology and colposcopy and not aggressive retreatment.
- Published
- 1997
811. Adult height and incidence of cancer in male physicians (United States).
- Author
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Hebert PR, Ajani U, Cook NR, Lee IM, Chan KS, and Hennekens CH
- Subjects
- Adult, Aged, Aged, 80 and over, Follow-Up Studies, Humans, Incidence, Male, Middle Aged, Multivariate Analysis, Neoplasms epidemiology, Prevalence, Risk, United States epidemiology, Body Height, Neoplasms etiology, Physicians
- Abstract
Adult height has been found in some but not all studies to be associated positively with overall cancer incidence as well as several site-specific cancers. The Physicians' Health Study (PHS), a randomized trial of beta-carotene and aspirin in the primary prevention of cancer and cardiovascular disease in men, provided an opportunity to examine the association between height and total malignant neoplasms (excluding non-melanoma skin cancer), as well as site-specific cancers including prostate, colorectal, and lung cancer. The PHS is comprised of 22,071 US male physicians in the United States, a population homogeneous for adult socioeconomic status, aged 40 to 84 years in 1982. Participants were classified into five height categories at study entry. After an average follow-up of over 12 years, there were 2,566 cases of incident total malignant neoplasms, including 1,047 prostate, 341 colorectal, and 170 lung cancer cases. Height was associated positively with both total malignant neoplasms and prostate cancer. Compared with men in the shortest category (<67 inches), relative risks and 95 percent confidence intervals (CI) for total malignant neoplasms for men whose height (in inches) was 68-69, 70-71, 72, and 73+ were, respectively: 1.13 (CI = 0.99-1.28), 1.15 (CI = 1.02-1.30), 1.29 (CI = 1.12-1.49), and 1.21 (CI = 1.05-1.39), P trend 0.001, adjusted for age, randomized treatment assignments, body mass index (wt/ht2), cigarette smoking, alcohol use, and exercise frequency. For prostate cancer, the corresponding RR values were 1.23 (CI = 1.00-1.51), 1.26 (CI = 1.04-1.54), 1.59 (CI = 1.27-1.98), and 1.26 (CI = 1.00-1.59), P trend 0.005. For colorectal cancer, in some but not all height categories compared with the shortest, there were elevated RRs without a significant linear trend: RR = 1.51 (CI = 1.06-2.14), 1.14 (CI = 0.80-1.62), 1.19 (CI = 0.79-1.80), and 1.53 (CI = 1.04-2.25), P trend 0.23. In contrast, there was no evidence of an association of height with lung cancer. These data indicate a positive association between height and risk of total malignant neoplasms, as well as of prostate cancer and, possibly, colorectal cancer.
- Published
- 1997
- Full Text
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812. A three-year review of treatment of cervical intraepithelial neoplasia with large loop excision of the transformation zone.
- Author
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Chan KS, Kwok CW, Yu KM, Sin SY, and Tang LC
- Abstract
One hundred and eighty-five patients were treated with large loop excision of the transformation zone for cervical intraepithelial neoplasia from October 1992 through September 1994. All patients were followed up regularly until September 1995 to review the outcome and morbidity. Cure rates of 97.2% in the first six months and 95.4% at the end of the first 12 months were obtained. Thirteen patients (7.0%) were admitted as emergency cases for post-operative haemorrhage, which required suturing, cauterisation with silver nitrate or electrocoagulation, vaginal douching, or antibiotic treatment. One patient developed cervical stenosis and incomplete excisions were noted in 46 (24.9%) patients. Eleven (6.0%) patients had cervical carcinomas detected. Our findings further confirm that this method is a reliable and safe way to treat cervical intraepithelial neoplasia with an acceptable rate of morbidity.
- Published
- 1997
813. Monitoring the therapy of pulmonary tuberculosis by nested polymerase chain reaction assay.
- Author
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Yuen KY, Chan KS, Chan CM, Ho PL, and Ng MH
- Subjects
- Adult, Aged, Antitubercular Agents therapeutic use, DNA Primers, DNA Probes, Female, Humans, Male, Middle Aged, Sputum microbiology, Tuberculosis, Pulmonary diagnosis, Mycobacterium tuberculosis isolation & purification, Polymerase Chain Reaction, Tuberculosis, Pulmonary drug therapy
- Abstract
Monthly clinical and microbiological parameters (by sputum smear, culture and PCR assay), of 50 patients with documented pulmonary tuberculosis and on anti-tuberculosis therapy, were monitored over a period of 18 months. PCR converters (70%) who had PCR conversion before the sixth month of treatment did not have clinical or microbiological evidence of failure or relapse, while nine of 15 PCR persisters (30%) had clinical failure (7) and relapse (2). The PCR persisters were significantly associated with more underlying medical illnesses, high mean radiographic scores on the extent of disease involvement, previous drug treatment, initial sputum smear positivity and multi-drug resistance. Of the eight PCR persisters infected by susceptible Mycobacterium tuberculosis, all had marked residual radiographic changes despite completion of drug therapy. The findings may have important implications in the application of PCR on individualization of the duration of anti-tuberculosis therapy.
- Published
- 1997
- Full Text
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814. Endobronchial tuberculosis: diagnostic features and therapeutic outcome.
- Author
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Hoheisel G, Chan BK, Chan CH, Chan KS, Teschler H, and Costabel U
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Antitubercular Agents therapeutic use, Biopsy, Bronchoscopy, Female, Fiber Optic Technology, Humans, Male, Middle Aged, Tracheal Stenosis prevention & control, Bronchial Diseases diagnosis, Tuberculosis, Pulmonary diagnosis
- Abstract
Background: Endobronchial tuberculosis (EBTB) is not seen often in the adult population. In most cases it is associated with pulmonary tuberculosis. During its course significant tracheobronchial stenosis may develop. In this study we report our experience with patients with EBTB., Methods: The records of 38 patients in whom EBTB had been proved by fibre optic bronchoscopy, microbiology and histology studies were evaluated., Results: Symptoms were non-specific and represented mainly the co-existing pulmonary tuberculosis. Signs characteristic of airway obstruction were rare (localized wheezing in 6%). Indications for bronchoscopy were radiographic features (87%), microscopy smear negatives (8%), wheezing (3%), and blood stained sputum (3%). The lesions were more likely to be seen in the main and upper bronchi. In 5% of patients the lower trachea was involved. Most lesions looked inflamed (51%), followed by caseous (19%), granulomatous (17%), ulcerative (12%), and fibrotic appearance (1%). The degree of stenosis was nil (22%), minor (45%), significant (13%), subtotal (13%), or total (7%). The patients were treated with a combination of antituberculosis drugs. Four patients underwent surgical procedures. Dilatation techniques were used in two patients for a right and left main bronchus stenosis respectively, with significant improvement in one. Dilatation in combination with laser therapy of a right intermediate bronchus stenosis did not result in re-expansion of the dependent part of the lung due to pleural adhesions. Left pneumonectomy was performed in one patient for destroyed lung. Twenty-two patients agreed to follow up bronchoscopy. The macroscopic appearance of the mucosa had improved in most cases but the degree of stenoses was unchanged in a considerable proportion (58%). Bronchial stenosis in one patient subsided during therapy but developed again at a later stage., Conclusions: Patients with pulmonary tuberculosis and radiographic evidence of volume loss are recommended to undergo bronchoscopy to rule out EBTB. Specific symptoms for EBTB are rare. Biopsy of inflamed areas of bronchial mucosa seems to be indicated. Despite adequate antituberculosis therapy tracheobronchial stenosis may develop. Long term follow up including bronchoscopy seems therefore advocated. Dilatational intervention may be indicated in selected cases.
- Published
- 1994
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815. Benzodiazepine peptidomimetic inhibitors of farnesyltransferase.
- Author
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Marsters JC Jr, McDowell RS, Reynolds ME, Oare DA, Somers TC, Stanley MS, Rawson TE, Struble ME, Burdick DJ, and Chan KS
- Subjects
- Amino Acid Sequence, Benzodiazepines chemical synthesis, Cell Membrane Permeability, Farnesyltranstransferase, Models, Molecular, Molecular Sequence Data, Oligopeptides chemical synthesis, Oligopeptides metabolism, Oligopeptides pharmacology, Structure-Activity Relationship, Transferases metabolism, Alkyl and Aryl Transferases, Benzodiazepines pharmacology, Transferases antagonists & inhibitors
- Abstract
A structural survey of protein Zn2+ binding geometries was instigated based upon the functional requirement of Ras farnesyltransferase for Zn2+. The Cys-X-X-Cys motif found in Zn(2+)-binding proteins such as aspartate transcarbamylase was used as a template to devise a bidentate-coordination model for Cys-A1-A2-X peptide inhibitors. Accordingly, replacement of the central dipeptide with the hydrophobic scaffold 3-amino-1-carboxymethyl-2,3-dihydro-5- phenyl-1H-1,4-benzodiazepin-2-one (BZA) yielded a peptidomimetic inhibitor, Cys(BZA)Met, of moderate potency (IC50 = 400 nM). N-Methylation of the cysteine amide improved potency almost 100-fold (IC50 = 0.3-1 nM). The increased affinity presumably correlates with a preferred conformation of the inhibitor which maximizes a hydrophobic interaction between the scaffold and the enzyme, and the proper presentation of cysteine and methionine to allow bidentate coordination at Zn2+. These non-peptide inhibitors have been shown to block farnesylation of the Ras protein in intact cells and provide lead compounds for the development of new cancer therapeutic agents.
- Published
- 1994
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816. Semi-automatic quantitation of nucleolar organizer regions in non-Hodgkin's lymphomas.
- Author
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Kalir T, Chan KS, Liu Z, Strauchen J, and Gil J
- Subjects
- Humans, Lymphoma, Non-Hodgkin classification, Multivariate Analysis, Silver, Staining and Labeling, Lymphoma, Non-Hodgkin ultrastructure, Nucleolus Organizer Region ultrastructure
- Abstract
Nucleolar organizer regions may be useful in the diagnosis and classification of non-Hodgkin's lymphomas. In this study of 46 cases we applied morphometric analysis with quantitation of physical descriptors of the nuclear profile (area, perimeter) and both number and area of stained nucleolar organizers therein enclosed to a series of lymphomas and benign lymphoid infiltrates. While nuclear outlines were manually traced small organizer regions within the nuclear profiles were semi-automatically outlined by a thresholding procedure subjected to manual override. This results in determination of number, area and perimeter of organizer regions. Data were corrected for section thickness effects and a stereologic (three-dimensional) analysis was additionally performed. We found an increase in mean number and area of nucleolar organizers per nucleus in high grade lymphomas compared to benign infiltrates and lower grade lymphomas. Volume and thickness corrected data showed a decrease in organizer number with concomitant increase in organizer volume in the higher grade lymphomas. Multivariate analysis of the cases, previously classified histologically, showed that clear resolution could be obtained, on the basis of physical descriptors, both between as well as within groups of the three tumor grades.
- Published
- 1994
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817. Disseminated histoplasmosis mimicking miliary tuberculosis: a case report.
- Author
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Chan KS, Looi LM, and Chan SP
- Subjects
- Adult, Diagnosis, Differential, Humans, Male, Diabetes Mellitus, Type 1 immunology, Histoplasmosis pathology, Immunocompromised Host, Tuberculosis, Miliary pathology
- Abstract
A 35-year-old Chinese man who was known to have insulin-dependent diabetes mellitus was admitted for fever and weight loss. During his hospital stay, he fell to his death from his ward at the twelfth floor. The clinical features, radiological findings and gross organ changes at autopsy closely simulated miliary tuberculosis. Histology, however, revealed extensive necrosis of the adrenal glands, lungs, spleen, kidneys and thyroid associated with the presence of Histoplasma capsulatum organisms. This case highlights the similarity both clinically and pathologically between histoplasmosis and tuberculosis and emphasizes the need to be aware of this infection in a nonendemic area among patients with a compromised immune system.
- Published
- 1993
818. Quantitative perimeter and area measurements of digital images.
- Author
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Barba J, Chan KS, and Gil J
- Subjects
- Animals, Humans, Microscopy instrumentation, Image Processing, Computer-Assisted methods, Microscopy methods, Signal Processing, Computer-Assisted
- Abstract
Quantitative estimations of perimeter and area from digitized video images, and the application of these features in morphometry, are discussed. Estimations from manual tracings via interactive peripherals and from chain codes are addressed. Topics discussed are calibration, determination of vertical and horizontal pixel resolution, effects of tracing jitter, and for chain codes, the spatial quantization scheme representation of the digital contour. Finally, new perimeter estimators for 4-connected and 8-connected chain codes for non-unity pixel aspect ratio are presented with simulation results.
- Published
- 1992
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819. Cyclic RGD peptide analogues as antiplatelet antithrombotics.
- Author
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Barker PL, Bullens S, Bunting S, Burdick DJ, Chan KS, Deisher T, Eigenbrot C, Gadek TR, Gantzos R, and Lipari MT
- Subjects
- Amino Acid Sequence, Cyclization, Enzyme-Linked Immunosorbent Assay, Fibrinolytic Agents chemistry, Fibrinolytic Agents pharmacology, Humans, Molecular Conformation, Molecular Sequence Data, Molecular Structure, Peptides chemistry, Peptides pharmacology, Peptides, Cyclic chemistry, Peptides, Cyclic pharmacology, Platelet Aggregation drug effects, Platelet Aggregation Inhibitors chemistry, Platelet Aggregation Inhibitors pharmacology, Platelet Membrane Glycoproteins metabolism, Receptors, Immunologic metabolism, Structure-Activity Relationship, Sulfoxides chemistry, Sulfoxides pharmacology, X-Ray Diffraction, Fibrinolytic Agents chemical synthesis, Peptides chemical synthesis, Peptides, Cyclic chemical synthesis, Platelet Aggregation Inhibitors chemical synthesis, Receptors, Immunologic chemistry, Receptors, Peptide, Sulfoxides chemical synthesis
- Abstract
Stimulation of platelets activates GPIIbIIIa, the heterodimeric integrin receptor, to bind fibrinogen (Fg), which results in platelet aggregation. GPIIbIIIa/Fg binding inhibitors are potentially suitable for acute use during and after thrombolytic therapy as antithrombotic agents. Incorporation of the tripeptide sequence Arg-Gly-Asp (RGD), a common structural element of many integrin ligands, into cyclic peptides produced a series of peptides of the general structure BrAc-(AA1)-RGD-Cys-OH, which were prepared by solid-phase peptide synthesis. Cyclization was accomplished by reaction of the N-terminal bromoacetyl group with the cysteine sulfhydryl at pH 8 at high dilution, resulting in thioether-bridged cyclic peptides [cyclo-S-Ac-(AA1)-RGD-Cys-OH]. Use of alpha-substituted bromoacetyl groups gave rise to an analogous series of acetyl-substituted thioether-bridged cyclic peptides. Oxidation of the thioethers produced separable diastereomeric sulfoxide-bridged cyclic peptides. After thorough evaluation in a GPIIbIIIa ELISA assay and a platelet aggregation assay, G-4120 (70A; AA1 = D-Tyr; sulfoxide bridge) was selected for further investigation as an antithrombotic agent. G-4120 was equipotent in the platelet aggregation assay to kistrin, a highly potent inhibitor of fibrinogen-mediated platelet aggregation isolated from snake venom (IC50 = 0.15 microM).
- Published
- 1992
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820. [Involvement of the central nervous system in disseminated tuberculosis].
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Hoheisel G, Chan KM, Dai LK, Chan KS, Sun AJ, Luk WK, and Chan CH
- Subjects
- Adrenal Cortex Hormones therapeutic use, Adult, Antitubercular Agents therapeutic use, Brain Diseases diagnostic imaging, Brain Diseases etiology, Brain Stem, Central Nervous System Diseases drug therapy, Cerebellar Diseases etiology, Hemiplegia etiology, Humans, Male, Middle Aged, Tomography, X-Ray Computed, Tuberculoma diagnostic imaging, Tuberculoma etiology, Tuberculosis, Meningeal etiology, Tuberculosis, Pulmonary complications, Tuberculosis, Pulmonary drug therapy, Central Nervous System Diseases etiology, Tuberculosis diagnostic imaging, Tuberculosis drug therapy
- Abstract
Four weeks after starting tuberculostatic treatment (with isoniazid, rifampicin, streptomycin and pyrazinamide) a 21-year-old man with pulmonary tuberculosis developed symptoms of a radiculomyelopathy as well as mild renal failure. After isoniazid and streptomycin had been discontinued and ethambutol and high doses of vitamin B6 had been added all signs and symptoms improved. However, 4 weeks later tuberculous meningitis occurred which at first seemed to respond to administration of 5 antituberculosis drugs and dexamethasone. But 3 weeks later the patient sustained a partial hemiparesis. Its cause was proven to be a tuberculoma in the region of the brainstem. During further administration of tuberculostatic drugs and glucocorticoids the symptoms gradually receded over 8 months. A 54-year-old man with pulmonary tuberculosis developed cranial nerve pareses and symptoms of cerebellar involvement (trunk ataxia, intention tremor, dysdiadochokinesia) 3 weeks after starting tuberculostatic treatment. Computed tomography revealed multiple intracerebral tuberculomas which gradually shrank with continuation of the tuberculostatic treatment plus glucocorticoids. These two case reports illustrate that in tuberculosis involvement of the CNS can express itself clinically through complex symptoms, sometimes even after the start of tuberculostatic treatment.
- Published
- 1991
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821. A dBASE III system for managing 35 mm slides in pathology.
- Author
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Wong KT and Chan KS
- Subjects
- Microcomputers, Pathology instrumentation, Software, Databases, Factual, Pathology methods
- Abstract
We describe the design and management of a 35 mm slide database using a menu-driven dBASE III PLUS programme and a microcomputer in a large department of pathology that also caters for the individual pathologist. Existing systems described in the literature are geared towards slides of general medicine and do not address the needs of the individual pathologist. A total of 11,481 slides in the Department of Pathology, Faculty of Medicine, University of Malaya, were filed into a single database with each record representing one slide. Nine fields which comprised the slide accession number, reference number, slide category, SNOMED codes, and a description of the slide in natural language, seemed adequate for slide definition. The menu-driven programme had functions which included the abilities to add, delete, edit and back-up records, and to search for desired slides. Although slides may be searched for in various fields, we found that searches using natural language alone were both comprehensive and efficient, provided a standard format of description was adhered to and data entries scrutinized carefully for errors. We believe therefore, that for the pathologist working alone, coded language fields are not absolutely necessary, as manual coding and additional data entry can be time consuming. As expected, for databases larger than 10,000 slides, a 80286 microprocessor-based microcomputer was more efficient. We are of the opinion that a system such as ours is very useful for a large department of pathology or the individual pathologist to file and retrieve 35 mm slides.
- Published
- 1990
822. The selection of patients for accelerated radiotherapy on the basis of tumor growth kinetics and intrinsic radiosensitivity.
- Author
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Tucker SL and Chan KS
- Subjects
- Dose-Response Relationship, Radiation, Humans, Radiation Tolerance, Stochastic Processes, Tumor Stem Cell Assay, Models, Theoretical, Radiotherapy methods, Radiotherapy Planning, Computer-Assisted
- Abstract
Mathematical modeling was used to reach qualitative conclusions concerning the relative rate of local tumor control that might be achieved by using accelerated fractionation to treat only the patients with the most rapidly growing tumors, compared with the control rates that could be expected from either conventional or accelerated radiotherapy alone. The results suggest that concomitant boost therapy is equally or more effective than conventional dose fractionation for all tumors, regardless of their growth kinetics. For tumors with very short clonogen doubling times, CHART (continuous hyperfractionated accelerated radiotherapy) may be even more effective than concomitant boost treatment, but CHART is less effective than conventional or concomitant boost therapy for tumors with longer clonogen doubling times. Thus, there is a rationale for using a predictive assay of tumor clonogen doubling times to identify the patients who should be treated with CHART. However, improvements in local tumor control resulting from concomitant boost treatment or the selective use of CHART are not likely to be apparent in the population as a whole, because the overall control rates are largely determined by refractory tumors having little chance of control with any of the treatments and by highly responsive tumors that are likely to be controlled regardless of the treatment choice. Differences in control rates with different treatment strategies are most apparent in the stochastic fraction of the population, which excludes those patients for whom there is either very little chance (e.g. less than 1%) or a very high chance (e.g. greater than 99%) of achieving local control with both treatments. The stochastic fraction can be approximated by excluding those patients with the most radioresistant and the most radiosensitive tumors, since intrinsic tumor radiosensitivity appears to be the single most important factor determining treatment outcome.
- Published
- 1990
- Full Text
- View/download PDF
823. Alterations in antigen-induced DNA synthesis by specifically localizing cells and other lymphoid cells as a function of immunological memory.
- Author
-
Thursh DR and Chan KS
- Subjects
- Animals, Female, Lymphocytes metabolism, Mice, Mice, Inbred CBA, Transplantation Immunology, DNA biosynthesis, Immunologic Memory, Lymphocytes immunology
- Published
- 1978
- Full Text
- View/download PDF
824. Taking the role of retarded children: effects of familiarity and similarity.
- Author
-
Kitano M and Chan KS
- Subjects
- Child, Concept Formation, Female, Humans, Male, Peer Group, Psychological Distance, Intellectual Disability psychology, Psychodrama, Role Playing
- Abstract
As a first step in improving social relations between nonhandicapped and retarded children, this study was designed to investigate children's ability to take a retarded child's role and the effects of two variables on this ability: (a) familiarity with the characteristics of retarded children and (b) similarity of experiences to those of retarded youngsters. Findings were interpreted as indicating that children's ability to take the perspective of retarded children may be a productive area for further research.
- Published
- 1978
825. Megaloblastic anaemia--a review from University Hospital, Kuala Lumpur.
- Author
-
Ng SC, Kuperan P, Chan KS, Bosco J, and Chan GL
- Subjects
- Anemia, Megaloblastic pathology, Anemia, Pernicious physiopathology, Bone Marrow pathology, Folic Acid blood, Humans, Pancytopenia physiopathology, Vitamin B 12 blood, Anemia, Macrocytic physiopathology, Anemia, Megaloblastic physiopathology
- Abstract
During a 5 year period, 28 adult patients with megaloblastic anaemia (MA) were treated in University Hospital. 71% of the patients were Indians. Symptoms of anaemia was the main presenting complaint in 18 (64%) of patients while in 2 patients peripheral neuropathy was the main problem. Pancytopenia was a common finding (present in 18 (64%) patients) while 6 (21%) patients had severe thrombocytopenia (less than 20 x 10(9)/L). The peripheral blood morphology provided important diagnostic clues i.e. macrocytes and/or hypersegmented neutrophils seen in most patients. Concurrent iron deficiency 'dampened' the megaloblastic picture. Though most patients suffered from MA of nutritional origin, 3 patients were diagnosed to have pernicious anaemia and 2 patients had myelodysplastic syndrome. Important practice points were detection of concurrent infection and hypokalemia which necessitated appropriate treatment. The controversy of blood transfusion in treatment of MA and the importance of reassessing patients after treatment were highlighted.
- Published
- 1988
826. Referential communication skill levels of moderately mentally retarded adolescents.
- Author
-
Rueda R and Chan KS
- Subjects
- Adolescent, Child Development, Female, Humans, Male, Psychological Theory, Psychology, Child, Communication, Intellectual Disability diagnosis
- Abstract
Referential communication skills of moderately mentally retarded adolescents (20 speaker-listener dyads) were investigated. In Study 1, subject performance on referential communication activities divided into three skill levels requiring sampling, comparison, and critical-features analysis was examined. Degree of idiosyncratic messages communicated by retarded speakers was investigated in Study 2. Listening competence of retarded and adult listeners was compared in Study 3. Retarded subjects did consistently better on referential communication tasks requiring only sampling than on tasks requiring comparison or critical analysis. Referential communication messages provided by retarded speakers did not have greater meaning to themselves than to others. Finally, retarded listeners and adult listeners did not differ significantly in their ability to utilize the information given by retarded speakers. Implications of the findings for the study of the social communications of retarded children were discussed.
- Published
- 1980
827. Immunologic cross-reactions between the specifically localizing cells (SLC) generated in response to sheep RBC and the red cells of other species.
- Author
-
Thursh DR and Chan KS
- Subjects
- Animals, Antigen-Antibody Reactions, Cattle, Chickens, Female, Horses, Humans, Isoantigens, Lymph Nodes immunology, Mice, Mice, Inbred CBA, Perissodactyla, Sheep, Species Specificity, Cross Reactions, Immunity, Cellular
- Abstract
Some of the lymphoid cells selectively incorporating radioactive thymidine 3 days after primary immunization with SRBC which are capable of specifically localizing in the lymph nodes of adoptively immunized syngeneic recipients challenged with SRBC (SLC-SRBC)2 are also capable of specifically localizing in lymph nodes challenged with the red blood cells of a varieth of other mammalian species. The one nonmammalian RBC tested, CRBC, failed to cross-react with SRBC by this parameter even qualitatively, although it remains possible that a feeble cross-reaction might be demonstrated with large enough experimental groups. As expected, the magnitude of the observed cross-reactions seems to vary inversely with the phylogenetic distance between the species, with ORBC showing the strongest cross-reaction (41 to 49%), ARBC showing the weakest (8 to 13%), and BRBC and HRBC occupying intermediate positions (13 to 20%). Cross-reaction between secondary anti-SRBC antibodies and the red cells of the other species were weak and inconstant, suggesting that the observed cross-reactions of specific localization may involve T cells more than B cells. During the course of these studies, it was also possible to verify experimentally our impression that with existing methods of selectively labeling SLC it is possible to study the phenomenon of specific localization using only one population of labeled cells, providing certain essential controls are employed.
- Published
- 1976
828. Survey of literature related to the problems of gas embolism in human body.
- Author
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Chan KS and Yang W
- Subjects
- Embolism, Air blood, Embolism, Air therapy, Humans, Embolism, Air diagnosis, Embolism, Air physiopathology, Gases blood, Gases chemistry, Models, Cardiovascular
- Published
- 1969
- Full Text
- View/download PDF
829. A sliding bracket shoe-piece: a new device to assist brace loading.
- Author
-
Iqbal QM, Chan KS, and Yin L
- Subjects
- Femoral Fractures therapy, Femur, Femur Head Necrosis therapy, Fibula injuries, Fractures, Bone therapy, Hip, Humans, Osteochondritis therapy, Osteomyelitis therapy, Syndrome, Tibial Fractures therapy, Tuberculosis, Osteoarticular therapy, Braces
- Published
- 1973
830. Behavior of gas emboli subjected to pressure variation in biological systems.
- Author
-
Chan KS and Yang WJ
- Subjects
- Computer Simulation, Humans, Sensitivity and Specificity, Blood Flow Velocity, Blood Pressure, Embolism blood, Embolism physiopathology, Gases blood, Models, Cardiovascular, Pulsatile Flow
- Published
- 1969
- Full Text
- View/download PDF
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