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Biomedical subjects

D Mandel

Publications and source records attributed to D Mandel.

28 records · Page 2Linked to original sources
PubMed1984

Reactivity of sized thermal aggregates of immunoglobulin G with IgM rheumatoid factor.

Solutions of purified pooled human IgG heated for varying times and temperatures between 55 degrees and 65 degrees yielded soluble turbid non-immune polydispersed aggregate mixtures. Gel filtration of IgG aggregate mixtures on calibrated Biorad A-15, A-50 or A-150 columns resulted in continuous size distributions from dimers to particles with mol. wts. as high as 5 X 10(7) (300-mers) with no particular size predominant. Chromatographically reproducible cuts of relatively narrow size heterogeneity were obtained by 15 min time fractionation. The reactivity of sized aggregates was studied with pooled purified IgM rheumatoid factor as well as with various individual IgM RF sera. The inhibition of agglutination method employing IgG-coated tanned sheep cells was used to assay relative reactivities. With all RF preparations studied, reactivity of sized IgG was primarily a function of aggregate size. Reactivity increased from virtually zero with monomeric IgG to maximal values with aggregates in the 10(6) size range. Larger aggregates (mol. wt. 10(7) or greater) exhibited diminishing and ultimately negligible reactivity. Reactivity of aggregates of given size was independent of heating time but increased with decrease in heating temperature. The maximal reactivity of certain sizes of IgG aggregates with RF suggests that at least two factors are operative. Enhanced reactivity may be due to unblocking of potential reactive sites on IgG during denaturation that precedes aggregation or to the more favourable energetics of binding with aggregates as compared to monomer. Subsequent loss of reactivity may be due to steric hindrance in large aggregates and/or to destruction of binding sites as a result of continued denaturation.

Binding Sites, Antibody↗
PubMed1983

Size fractionation of thermal aggregates of immunoglobulin G.

Purified pooled human immunoglobulin G (IgG) in solution, when extensively heated at high temperatures or for long periods, irreversibly aggregates and insoluble precipitates result. However, when IgG solutions are heated in the temperature range 55-65 degrees C for more limited time periods, soluble turbid polydispersed aggregate mixtures are obtained. Gel filtration of such aggregate mixtures on calibrated Bio-Rad A-150m columns demonstrates a continuous size distribution from dimers to aggregates as large as 4 X 10(7) Da (200-mers) with no particular size predominant. Chromatographically reproducible cuts of narrow size heterogeneity can be obtained by short-time fraction collection. Elution-time reproducibility is excellent both for mixture and for individual cuts. Stability studies indicate that reproducible and stable aggregates may be made from purified IgG and that fractionated aggregates should be stored quick-frozen until needed. Sized IgG aggregates have proved useful in reactivity studies with rheumatoid factor, animal anti-IgG antibodies, and complement.

Chromatography, Gel↗
PubMed1978

Sipple's syndrome with a malignant pheochromocytoma presenting as a pericardial effusion.

Sipple's syndrome is a multiple endocrinopathy usually involving the adrenal medulla and the thyroid. In the present case, a malignant pheochromocytoma metastasized to the pericardium and both lungs. The patient was known to have had a calcified right suprarenal mass for 8 years. He was admitted to the emergency room with symptomatology consistent with pericardial tamponade, but despite intensive management, he expired.

Adrenal Gland Neoplasms↗
PubMed1977

The Environmental fate of three carcinogens: benzo-(alpha)-pyrene, benzidine, and vinyl chloride evaluated in laboratory model ecosystems.

Radiolabeled benzo-((alpha)-pyrene, benzidine, and vinyl chloride were evaluated in laboratory model ecosystems for environmental fate, degradation pathways, bioconcentration, and food chain accumulation. The comparative effects of microsomal detoxications were evaluated using the inhibitor piperonyl butoxide. The accumulation and bioconcentration of benzo-(alpha)-pyrene and benzidine were closely correlated with their octanol/water partition coefficients and water solubility. Benzo-(alpha)-pyrene as predicted by these parameters was bioaccumulated to substantial levels in several organisms. Vinyl chloride was not accumulated because of its high volatility.

Animals↗
PubMed1976

Lack of efficacy of thermography as a screening tool for minimal and stage I breast cancer.

In a study of thermograms of 42 patients with Stage 1 or smaller carcinomas of the breast, 44 confounding cases and 64 randomly selected subjects being screened, we found that the ability of expert thermographers to identify the patients with carcinoma correctly (true positive = 0.238) varied little from the ability of untrained readers (true positive = 0.301). Furthermore, in the expert group, the indexes of suspicion were so high (0.436) and the true-positive levels were so relatively low (0.238, P = 0.0005) that thermography may well have a very limited role as a screening or pre-screening modality for the detection of minimal or Stage 1 breast cancers.

Breast Neoplasms↗
PubMedDate not supplied

Occupational therapy for independent-living older adults. A randomized controlled trial.

CONTEXT: Preventive health programs may mitigate against the health risks of older adulthood. OBJECTIVE: To evaluate the effectiveness of preventive occupational therapy (OT) services specifically tailored for multiethnic, independent-living older adults. Design.-A randomized controlled trial. SETTING: Two government subsidized apartment complexes for independent-living older adults. SUBJECTS: A total of 361 culturally diverse volunteers aged 60 years or older. INTERVENTION: An OT group, a social activity control group, and a nontreatment control group. The period of treatment was 9 months. MAIN OUTCOME MEASURES: A battery of self-administered questionnaires designed to measure physical and social function, self-rated health, life satisfaction, and depressive symptoms. RESULTS: Benefit attributable to OT treatment was found for the quality of interaction scale on the Functional Status Questionnaire (P=.03), Life Satisfaction Index-Z (P=.03), Medical Outcomes Study Health Perception Survey (P=.05), and for 7 of 8 scales on the RAND 36-Item Health Status Survey, Short Form: bodily pain (P=.03), physical functioning (P=.008), role limitations attributable to health problems (P=.02), vitality (P=.004), social functioning (P=.05), role limitations attributable to emotional problems (P=.05), and general mental health (P=.02). CONCLUSIONS: Significant benefits for the OT preventive treatment group were found across various health, function, and quality-of-life domains. Because the control groups tended to decline over the study interval, our results suggest that preventive health programs based on OT may mitigate against the health risks of older adulthood.

Activities of Daily Living↗