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Biomedical subjects

D Zimmerman

Publications and source records attributed to D Zimmerman.

At least 127 records · Page 7Linked to original sources
PubMed1980

Dose-response relation of CSF sodium and renal sodium excretion, and its absence in homozygous Brattleboro rats.

Constant intraventricular infusion (3.3--6.6 microliters/min) of artificial cerebrospinal fluid with sodium concentrations of 100, 150, 200, 250, 300, and 350 mM produced a linear dose-related change in renal sodium excretion in conscious, unrestrained Sprague-Dawley rats. The periventricular receptors stimulated were able to evoke substantial changes in body sodium balance; the 350 mM Na CSF produced an estimated 14% deficit in the content of Na in the extracellular fluid over a 5-hour infusion period. This is the first demonstration of such a dose-response relation over a wide range of CSF Na concentration (above and below normal) in conscious animals. Both the dose-response relation, and the magnitude of the effects, suggests an important physiologic role for this control mechanism. The natriuresis in response to 300 mM sodium infusion was identical in Long-Evans Brattleboro rats heterozygous for diabetes insipidus (DI), and in Sprague-Dawley rats, but was completely absent in homozygous animals. Although the experimental methods (conscious unrestrained rats) precluded simultaneous evaluation of efferent pathways other than antidiuretic hormone (ADH), the evidence from the DI rats suggests that ADH may be the efferent pathway for the response.

Animals↗
PubMed1980

Serotonin stimulates adenosine 3',5'-monophosphate accumulation in parathyroid adenoma.

The effect of serotonin on cAMP accumulation in parathyroid adenoma tissue from patients with primary hyperparathyroidism was studied in vitro. Incubation with 10(-5) M serotonin elicited a marked increase (of 90--150%) in cAMP content in slices of parathyroid adenoma tissue. This stimulatory effect of serotonin was already apparent after 2 min of incubation; stimulation by serotonin was dose dependent, with the highest stimulation being achieved at 10(-4) M serotonin. The serotonin antagonists, methylsergide and cinanserin, in concentrations equimolar to serotonin completely blocked the stimulatory effect of serotonin on cAMP increase. The serotonin content in surgically removed parathyroid adenoma tissue, as determined by fluorometric assay, was 6.4 +/- 1.2 pmol/mg wet wt (approximately 0.8 x 10(-5) M). The present observations demonstrate that parathyroid adenoma tissue has a high content of serotonin, and serotonin stimulates cAMP accumulation in this tissue. Since cAMP acts as a mediator of parathyroid hormone (PTH) release, our results suggest that serotonin could be one of the factors regulating PTH secretion and/or contributing to PTH hypersecretion in various forms of primary hyperparathyroidism.

Adenoma↗
PubMed1979

H-Y antigen. Cell surface mapping and testosterone-induced supramolecular repatterning.

Previous work with the antibody-blocking technique showed that the map of surface components for thymocytes prefixed with paraformaldehyde is the same as the map for unfixed thymocytes, with the following exception: after exposure to anti-TL or anti-Db, TL and H-2Db occupy adjacent positions on unfixed cells but not on fixed cells. This was interpreted as an indication that activation of particular components of the surface phenotype initiates ordered changes in the display of cell-surface molecules, approximation of TL and Db in this instance. These studies have now been extended to the H-Y component on the surface of male cells. On fixed male mouse thymocytes, H-Y lies adjacent to TL and relatively distant from H-2Db, H-2Kb, H-2Lb, Lyt-1.2, and Lyt-2.2. However, on unfixed male mouse thymocytes, similarly exposed to H-Y antibody, H-Y and H-2Db are adjacent. Presumably, this engagement of H-Y sites by H-Y antibody brings H-Y and H-2Db together. Evidence that this change in pattern may be physiologically relevant comes from the finding that testosterone, but not estradiol, caused the same selective approximation of H-Y and H-2Db.

Animals↗
PubMed1979

Hypnosis.

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Attitude of Health Personnel↗
PubMed1979

Surface mapping of mouse thymocytes.

The blocking method used previously for determining the relative positions of different components of the cell surface was modified by first fixing the cells with paraformaldehyde. This technique was applied to the H-2K (K), H-2D (D), TL, Lyt-1, and Lyt-2 surface components of mouse thymocytes, and the results were compared in parallel with data obtained with the original technique with unfixed cells. Previous mapping data with unfixed cells, indicating the positions of these molecules relative to one another, were confirmed with paraformaldehyde-fixed cells, with one exception. On unfixed cells, D and TL appeared sufficiently adjacent to produce mutual interference in the attachment of anti-D and anti-TL antibodies. With paraformaldehyde-fixed cells this was not so, D and TL appearing sufficiently separated from one another to obviate interference in the attachment of anti-D and anti-TL antibodies. The previously reported close association of K with Lyt-1 and of D with Lyt-2 were demonstrable equally with unfixed and paraformaldehyde-fixed thymocytes. It is suggested that activation of D sites, and alternatively of TL sites, by antibody in the present experiments brings these two molecules into apposition and that this movement may exemplify a mechanism concerned in immunological recognition and response.

Animals↗
PubMed1978

Qa-2 and Qa-3 antigens on lymphocyte subpopulations. I. Mitogen responsiveness.

The effects of anti-Qa-2 plus C and anti-Qa-3 plus C on mitogen-induced proliferation were studied. Both of these antisera in the presence of C markedly reduced both Con A- and PHA-induced proliferation while having little or no effect on LPS-induced proliferation. LPS, Con A, and PHA cultures and cultures containing media alone, examined at 72 hr, contained high proportions of Qa-2+ and Qa-3+ cells.

Animals↗
PubMed1977

The Tla locus: a new allele and antigenic specificity.

Four of 23 H-2 alloantisera screened for anti-TL activity contained such activity. One of these alloantisera, D-35, defined a new TL specificity, TL.5, and a new Tla allele, Tlad. TL.5 has all the characteristics of a TL antigen and has a different strain distribution than previously known ones. This new complexity at the Tla locus and the previous finding of other serologically defined genes in the Tla region indicate that this genetic region cannot be ignored in analyzing antisera produced in strains made congenic for the major histocompatibility complex.

Alleles↗
PubMed1976

Bacterial endocarditis in a patient with Marfan's syndrome.

A patient with Marfan's syndrome and subacute bacterial endocarditis is presented. Echocardiographic studies demonstrated dilatation of the aortic root, prolapse of the posterior leaflet of the mitral valve, and the appearance of shaggy echoes on the anterior miltral leaflet, of the kind previously described as representing bacterial vegetations.

Adult↗