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Biomedical subjects

D White

Publications and source records attributed to D White.

At least 343 records · Page 19Linked to original sources
PubMed1982

Natural killer (NK) activity in peripheral blood lymphocytes of patients with benign and malignant breast disease.

Previous studies of natural killer (NK) activity in the peripheral blood of breast cancer patients have failed to show a reduction in cytotoxicity, an observation at variance with results obtained in other malignancies. Interpretation of the data however is complicated by the presence of treated and post-mastectomy patients in the groups studied.In this study, lymphocytes from preoperative blood samples of untreated women with benign and malignant breast disease were tested at various effector-to-target ratios for cytotoxicity activity against the NK sensitive erythromyeloid cell line, K562.A significant reduction in NK activity was observed between carcinoma patients and the control group (P=0·02). When the carcinoma group was further divided into pre- and postmenopausal patients, the reduction was found to be a feature only of premenopausal women (P=0·002). The levels of NK activity in patients with benign breast disease were not significantly different from those in controls, irrespective of menstrual status. There was no correlation between NK activity and tumour size, oestrogen-receptor or lymph-node status in the carcinoma patients.A preliminary analysis of NK activities in the control group suggests that women donating blood in the first half of their menstrual cycle show significantly reduced NK activity in comparison with those in the second half (P=0·001). This finding, coupled with the variation in NK activity shown between pre- and postmenopausal breast carcinoma patients, suggests that hormonal effects in conjunction with malignancy determine the level of NK activity in breast cancer.

Adult↗
PubMed1982

Alternatives to beta-blockade in therapy of hypertension with angina pectoris: role of nifedipine or of labetalol.

1 Patients with combined hypertension and angina pectoris may represent a therapeutic dilemma, with the angina being refractory to conventional beta-blockade. 2 The added benefit of peripheral vasodilation in control of blood pressure is documented in the case of nifedipine. 3 Improved blood pressure control by added nifedipine may not be accompanied by decreased severity of angina pectoris, emphasizing the complex causation of the angina in such patients. 4 The clinically proven added alpha-blocking activity of labetalol distinguishes labetalol from other beta-blockers. However, the suggested benefits of the added alpha-activity in patients with hypertension and angina remain to be proven by further trials in patients.

Angina Pectoris↗
PubMed1982

Pheromone produced by the myxobacterium Stigmatella aurantiaca.

An extracellular, diffusible signaling molecule (pheromone) was produced by Stigmatella aurantiaca during fruiting body formation. The pheromone decreased the aggregation period in both the light and the dark and substituted for light in stimulating the maturation of aggregates into fruiting bodies. The cells were more sensitive to lower concentrations of pheromone in the light than in the dark, possibly explaining the stimulation of aggregation and fruiting body formation by light. The pheromone also interacted cooperatively with GMP to shorten the aggregation period. The pheromone behaved chemically as a low-molecular-weight lipid.

Animals↗
PubMed1982

A surface polysaccharide of Escherichia coli O111 contains O-antigen and inhibits agglutination of cells by O-antiserum.

The repeating pentasaccharide of O-antigen from Escherichia coli O111 contains galactose, glucose, N-acetylglucosamine, and colitose, the latter representing the major antigenic determinant. Phenol extraction of this strain was previously shown to release two fractions (I and II) containing O-antigen carbohydrate, and both fractions were believed to be lipopolysaccharide. We have now characterized fractions I and II and conclude that only fraction II represents lipopolysaccharide. Fraction II contains phosphate, 2-keto-3-deoxyoctonate, beta-hydroxymyristic acid, and potent endotoxin activity, whereas fraction I was deficient in all of these properties of the lipid A and core oligosaccharide regions of lipopolysaccharide. Fractions I and II each represented 50% of the total cellular O-antigen, and both were present on the cell surface. Both fractions were metabolically stable, and no precursor-product relationship existed between them. Fraction II had a number-average molecular weight of 15,800, corresponding to an average of 12 O-antigen repeats per molecule. In contrast, fraction I had a number-average molecular weight of 354,000, corresponding to an average of 404 O-antigen repeats per molecule. Before heat treatment, cells of E. coli O111 are poorly agglutinated by O-serum; although this indicates the presence of a capsule, the corresponding K-antigen was never detected. We conclude that fraction I, when present on the cell surface, inhibits agglutination of unheated cultures of E. coli O111 by O-serum because: (i) a variant strain which lacks fraction I was agglutinated by O-serum without prior heating; (ii) erythrocytes coated with purified fraction I behaved like bacteria containing fraction I in showing inhibition of O-serum agglutination; and (iii) heat treatment released fraction I and rendered bacterial cells agglutinable in O-serum.

Agglutination↗
PubMed1982

Bradycardia during sleep apnea. Characteristics and mechanism.

To determine the characteristics of and mechanisms causing the bradycardia during sleep apnea (SA), both patients with SA and normals were studied. Evaluation of six consecutive SA patients demonstrated that bradycardia occurred during 95% of all apneas (central, obstructive, and mixed) and became marked with increased apnea length (P less than 0.01) and increased oxyhemoglobin desaturation (P less than 0.01). Heart rate slowed 9.5 beats per minute (bpm) during apneas of 10-19 s in duration, 11.4 bpm during 20-39s apneas, and 16.6 bpm during 40-59-s apneas. Sleep stage had no effect unexplained by apnea length or degree of desaturation. Oxygen administration to four SA patients completely prevented the bradycardia although apneas lengthened (P less than 0.05) in three. Sleeping normal subjects did not develop bradycardia during hypoxic hyperpnea but, instead, HR increased with hypoxia in all sleep stages, although the increase in HR was not as great as that which occurred while awake. Breath holding in awake normals did not result in bradycardia during hyperoxia (SaO2 = 99%), but was consistently (P less than 0.01) associated with heart rate slowing during room air breath-holds (-6 bpm) at SaO2 = 93%, with more striking slowing (-20 bpm) during hypoxic breath-holds (P less than 0.01) at SaO2 = 78%. Breath holding during hyperoxic hypercapnia had no significant effect on rate. Breath holding in awake SA subjects demonstrated similar findings. We conclude that the bradycardia of SA is a consistent feature of apnea and results from the combined effect of cessation of breathing plus hypoxemia.

Adult↗
PubMed1982

Adjuvant antiplatelet therapy with aspirin in colo-rectal cancer.

Sixty-six patients with Duke's B2 or C colon or rectal cancer were randomized for treatment with aspirin (ASA), 600 mg, p.o., twice daily x 2 years or placebo (P). Compliance was checked in both groups by random measurement of blood salicylate levels. Fifty-seven patients are currently evaluable. No difference in disease-free (p = .66) or overall survival (p = .90) is present between ASA and P groups. The time at which ASA therapy is started (within 2 or within 4 weeks) following surgery does not affect these results. Aspirin at conventional dosage is ineffective in preventing the appearance of metastases in patients with colo-rectal cancer.

Actuarial Analysis↗
PubMed1982

Randomized trial of aminoglutethimide versus tamoxifen in metastatic breast cancer.

We compared antiestrogen therapy (tamoxifen) with an estrogen suppression regimen (aminoglutethimide-hydrocortisone) in postmenopausal women with metastatic breast carcinoma. Fifteen of 39 patients (38%) who received tamoxifen experienced an objective tumor regression (3 complete, 12 partial remissions), whereas 13 of 36 women (36%) receiving aminoglutethimide responded (one complete remission, 12 partial remissions). The median duration of response was similar. The site of tumor involvement appears to be important in choosing between these hormonal treatments. Aminoglutethimide appears to offer a greater chance of response in patients with bone involvement.

Aminoglutethimide↗
PubMed1981

Glycoproteins and human cancer: II. Correlation between circulating level and disease status.

Many cancer patients have elevated serum protein and sialic acid (N-acetyl neuraminic acid, NANA) levels. Serial determinations were performed, using serum treated with perchloric acid from 34 patients with widespread metastatic disease. Six of six patients who underwent debulking surgery had a drop in their serum NANA value to normal levels following a transient rise in the immediate postoperative period. Twenty-eight patients received chemotherapy and had serial NANA determinations over periods ranging from 4 to 12 months. Eleven of 28 patients demonstrated tumor regression or stable disease. Ten of the 11 in this group had a drop in their serum NANA level. The remaining 17 patients showed tumor progression, and serum NANA rose in 11 of 12 patients with widespread progression of metastatic disease. This elevation preceded clinical relapse in 8 of the 11 patients. Elevation did not occur in four of five patients with a local site relapse of disease (two chest wall, one lung mass, one brain metastases). Serial serum glycoprotein titers deserve further consideration as a monitor of response to chemotherapy of metastatic disease.

Antineoplastic Agents↗