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Biomedical subjects

D Hall

Publications and source records attributed to D Hall.

At least 217 records · Page 12Linked to original sources
PubMed1982

Differences in the composition of preterm and term human milk during early lactation.

The composition of human milk from mothers delivering prematurely (PT) and at term (T) was studied over the first weeks of lactation. Complete 24 h milk expressions were obtained by electric pump at weekly or biweekly intervals through 44 wk conceptual age (120 samples from 20 PT mothers and 28 samples from 7 T mothers). PT milk was found to contain significantly higher concentrations than T milk of the following nutrients: total nitrogen, protein nitrogen, sodium, chloride, magnesium and iron. No differences were found between T and PT milk for nonprotein nitrogen, volume, solids, total calories, lactose, fat, fatty acids, potassium or calcium. The nutrients supplied to a 33 wk preterm infant fed 200 ml/kg/day of "average" PT milk were in excess of theoretic intrauterine requirements for all substrates except calcium and phosphorus. PT human milk is theoretically more suitable for the premature infant than either mature or term human milk, but may be deficient in specific nutrients for the very low birth weight baby.

Calcium↗
PubMed1981

Regulation of vasopressin-sensitive adenylate cyclase by calmodulin.

It has recently been demonstrated that an established cell line from pig kidney, LLC-PK1, is a useful model for the study of vasopressin-sensitive adenylate cyclase (Roy, C., and Ausiello, D. A. (1981) J. Biol. Chem. 256, 3415-3422; Roy, C., Hall, D., Karish, M., and Ausiello, D. A. (1981) J. Biol. Chem. 256, 3423-3427). The present study on the regulation of this enzyme has led to the demonstration of the modulation of vasopressin-stimulated adenylate cyclase by Ca2+-calmodulin. The characteristics of calmodulin regulation were similar to those described for other enzymes: (a) activation required micromolar quantities of free Ca2+; (b) maximal enzyme rates were altered but not the Km for hormone activation; (c) activity was inhibitable by trifluoperazine; and (d) activation was dependent on the Mg2+ concentration. These findings should help to define the mechanisms of action of several agents known to alter vasopressin-sensitive adenylate cyclase and cell Ca2+ content.

Adenylyl Cyclases↗
PubMed1981

Relationship of (8-lysine) vasopressin receptor transition to receptor functional properties in a pig kidney cell line (LLC-PK1).

In intact LLC-PK1 cells, occupancy of vasopressin receptors (Roy, C., and Ausiello, D. A. (1981) J. Biol. Chem. 256, 3415-3522) correlated with cell cAMP production. This relationship was observed as a function of hormone dose, incubation time, and changes in receptor affinity. However, the rate of cAMP production diminished with time in intact cells exposed to high hormone concentrations, even in the presence of a phosphodiesterase inhibitor. A rapid desensitization of adenylate cyclase activity was observed in minutes upon treatment of intact cells with high hormonal concentrations. Desensitization was dose- and time-dependent. Hypertonic sodium chloride, which increased hormonal binding and cell cAMP production, prevented desensitization. The acute decrease in hormone-stimulated adenylate cyclase activity correlated with increased occupancy of low affinity binding sites. EDTA-suspended cells, which have a homogeneous population of binding sites, did not demonstrate desensitization. A proposal is made as to the consequences of this phenomenon at physiological concentrations of vasopressin.

1-Methyl-3-isobutylxanthine↗
PubMed1981

Management of a vaginal foreign body.

A case is presented of a vaginal foreign body. A drinking glass was inserted in the vagina of an intoxicated patient by her irate lover. Infection followed. The emergency care is described, including the method of extraction of the object, along with discussion of the principles involved and associated complications.

Female↗
PubMed1980

Methods for detection of left ventricular edges.

The ability to accurately and reproducibly measure left ventricular performance offers significant clinical advantages in patient management. Specifically, data on wall motion of the left ventricle, the characteristics and shape of the left ventricular volume curve, and measurement of ejection fraction are the general parameters of interest evaluated. These parameters may be measured with either first-pass studies or gated equilibrium blood pool images. Either method is relatively simple, economical, and presents little risk to the patient. Over the last several years both methods have undergone considerable study, and relatively standardized techniques for the two methods exist at present. Both techniques require moderate to extensive data processing. In general, a region of interest (ROI) must be defined before further quantitative analysis is possible. There are at present multiple approaches to the establishment of an ROI for the left ventricle. The major differences between these approaches is in the algorithms used to generate the boundary of the ROI or "the edge". In order for the computer to recognize the edge of the left ventricle, objective and reproducible edge-detection processes are needed. It is the purpose of this paper to review computerized edge-detection algorithms as they apply particularly to the noisy and blurry images obtained in nuclear medicine studies.

Heart Ventricles↗
PubMed1980

Klebsiella species in hospital food and kitchens: a source of organisms in the bowel of patients.

Hospital food was examined for the presence of Klebsiella species. Salads and cold meat were most frequently contaminated, often containing more than 10(3) organisms per g. Klebsiella species were also widely distributed in the kitchen environment which was considered, at least in part, to be the source of the organisms in food. By the use of serological and bacteriocin typing, intestinal carriage of strains ingested in food could be demonstrated.

Bacteriological Techniques↗
PubMed1980

Serial electrocardiographic changes during long-term treatment of severe hypertension with minoxidil.

The effects of minoxidil on the electrocardiogram (EKG) were assessed in a prospective investigation of 112 patients with severe hypertension during an observation period representing 241.5 patient-years. Highly significant blood pressure reductions at rest and during exercise were achieved and maintained with the combination of minoxidil, beta-adrenergic blocking agents, and diuretics. In 90% of the patients, the initiation of minoxidil was associated with nonspecific T-wave changes in the EKG consisting of flattening or inversion, which ranged from slight to very marked. While these changes may initially appear disconcerting, the observations of this study show that they are not related to changes in heart rate or other clinical criteria associated with myocardial ischemia. The changes remain unaltered during the tachycardia of exercise, they are not influenced by beta-adrenergic blockage, and they generally revert to their control appearance during chronic treatment. During long-term treatment, a substantial reduction of the increased QRS voltages occurred.

Adolescent↗