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Biomedical subjects

M Ng

Publications and source records attributed to M Ng.

118 records · Page 7Linked to original sources
PubMed1979

Effect of cyclic adenosine 3',5'-monophosphate antagonists on endotoxin-induced inhibition of human neutrophil chemotaxis.

We reported previously that Escherichia coli endotoxin inhibited human neutrophil chemotaxis toward C5a. This effect of endotoxin was antagonized by anti-inflammatory steroids. We now report that dibutyryl cyclic adenosine 3',5'-monophosphate, prostaglandin E1, isoproterenol, and cholera toxin also antagonize the suppression of chemotaxis by endotoxin. Each compound inhibited the effect of endotoxin in a dose-dependent fashion. To be effective, each compound except cholera toxin had to be present at the time of endotoxin challenge. Furthermore, propranolol blocked the protective effect of isoproterenol against endotoxin but not the protective effect of dibutyrl cyclic adenosine 3',5'-monophosphate or prostaglandin E1. Dibutyryl cyclic guanosine 3',5'-monophosphate, adenosine 5'-monophosphate, phenylephrine, prostaglandin F2 alpha, and carbachol did not modify the suppression of chemotaxis by endotoxin. Anti-inflammatory steroids and dibutyryl cyclic adenosine 3',5'-monophosphate are thought to stabilize phospholipids in certain cell membranes. This phospholipid-stabilizing action may contribute, at least in part, to the protective effect against endotoxin-mediated suppression of neutrophil chemotaxis.

Bucladesine↗
PubMedDate not supplied

Influence of cyclophosphamide and other immunosuppressive drugs on immune disorders and neoplasia in NZB/NZW mice.

NZB/NZW mice were treated with various immunosuppressive drugs used in human SLE. Cyclophosphamide (5 mg/kg 6 days out of 7), alone or with prednisolone, was better than azathioprine, prednisolone, or azathioprine-plus-prednisolone, in prolonging survival and/or reducing proteinuria, Coomb's antibodies, antinuclear antibodies, and glomerular deposits of gamma-globulin. Intermittent bolus therapy with cyclophosphamide (59 mg/kg/10 days) was as effective as daily therapy. However, 61% of the mice receiving any cyclophosphamide regimen developed malignant tumors compared to none in the other groups.

Animals↗
PubMedDate not supplied

Diagnostic value of sperm function tests and routine semen analyses in fertile and infertile men.

The results of routine semen analyses, the zona-free hamster oocyte penetration test, the hypoosmotic swelling test, and semen adenosine triphosphate levels were studied in 66 fertile and 130 infertile men. Multivariate discriminant analysis demonstrated that routine semen parameters including semen volume, sperm count, percent sperm motility, and percent normal spermatozoa in combination could predict the fertility of these patients with 70.4% accuracy. Of the three sperm function tests evaluated, the zona-free hamster oocyte penetration test and the hypoosmotic swelling test were selected by the multivariate discriminant analysis as variables capable of providing significant information on the fertility status of the patients. However, the addition of the results of these two tests to the routine semen analysis did not significantly improve the predictability of fertility. The overall correct prediction rate was 77.6% after incorporation of the results of these two sperm function tests. In this group of subjects, the presently available sperm function tests did not predict the fertility status of a patient with a high degree of accuracy.

Diagnostic Tests, Routine↗
PubMedDate not supplied

Evaluation of computerized analysis of sperm movement characteristics and differential sperm tail swelling patterns in predicting human sperm in vitro fertilizing capacity.

Multivariate discriminant analysis was used to evaluate the usefulness of computer image analysis of sperm movement characteristics and differential patterns of sperm tail swelling after hypoosmotic treatment for predicting the human sperm in vitro fertilizing capacity assessed by the zona-free hamster egg penetration assay. Fifty-five semen samples, mostly normospermic, from untreated infertility clinic patients were analyzed. The % normal sperm morphology, linearity of seminal sperm movement, seminal sperm head beat frequency, mean and maximum amplitudes of lateral head displacement, and hypoosmotic sperm tail swelling patterns c, d and f were selected by multivariate discriminant analysis to be capable of discriminating the samples exhibiting the presence or the absence of sperm in vitro fertilizing capacity. The % total sperm tail swelling did not give additional information about in vitro fertilizing capacity. These preliminary data suggest that computer image analysis of sperm movement characteristics and differential evaluation of hypoosmotic sperm tail swelling might be useful for the prediction of human sperm fertility. Further prospective studies are necessary to validate their predictive functions.

Evaluation Studies as Topic↗
PubMedDate not supplied

Colonic malacoplakia: unusual association with ulcerative colitis.

A 44 year old Chinese female with malacoplakia of the colon associated with ulcerative colitis was presented. The patient showed typical histological, electron microscopic and X-ray micro-analysis findings of malacoplakia. The malacoplakia gradually disappeared after discontinuation of high-dose systemic steroid prescribed by private practitioner for the ulcerative colitis. A review of the 26 previously reported cases of malacoplakia of the colon is also included. Coupled with the clinical events of this patient, it appears that malacoplakia is likely to be secondary to immunosuppression, due to drugs, malignant or debilitating diseases.

Adult↗
PubMedDate not supplied

Effects of a decision support system on the diagnostic accuracy of users: a preliminary report.

OBJECTIVES: To assess the effects of incomplete data upon the output of a computerized diagnostic decision support system (DSS), to assess the effects of using the system upon the diagnostic opinions of users, and to explore if these effects vary as a function of clinical experience. DESIGN: Experimental pilot study. Four clusters of nine cases each were constructed and equated for case difficulty. Definitive findings were omitted from the case abstracts. Subjects were randomly assigned to one of four clusters and were trained on the DSS prior to use. SUBJECTS: The study involved 16 physicians at three levels of clinical experience (six general internists, four residents in internal medicine, and six fourth-year medical students), from three academic medical centers. PROCEDURE: Each subject worked up nine cases, first without and then with ILIAD consultation. They were asked to offer up to six potential diagnoses and to list up to three steps that should be the next items in the diagnostic workup. Effects of DSS consultation were measured by changes in the position of the correct diagnosis in the lists of differential diagnoses, pre- and post-consultation. RESULTS: The DSS lists of diagnostic possibilities contained the correct diagnosis in 38% of cases, about midway between the levels of accuracy of residents and attending general internists. In over 70% of cases, the DSS output had no effect on the position of the correct diagnosis in the subjects' lists. The system's diagnostic accuracy was unaffected by the clinical experience of the users.

Decision Making↗