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Biomedical subjects

M Goldberg

Publications and source records attributed to M Goldberg.

At least 523 records · Page 29Linked to original sources
PubMed1985

Purification and partial characterization of a liver cell proliferation factor called hepatopoietin.

The purification and partial characterization of a liver cell proliferation factor called hepatopoietin are described. Hepatopoietin was isolated from remnant livers or blood plasma of partially hepatectomized rats and purified approximately 13,000-fold. The stokes radius was 2.65 +/- 0.2 nm and the apparent molecular weight was calculated to be 38,000 +/- 5,000 D. Hepatopoietin is a heat-stable glycoprotein and is organ specific but species nonspecific. In vivo it stimulates about three to four times the DNA synthesis as well as the mitotic rate of the liver of normal rats after i.p. injection. Hepatopoietin is inactivated upon incubation with galactosidase or trypsin-chymotrypsin.

Animals↗
PubMed1985

Autologous mixed lymphocyte reaction in man. XIII. Characterization of the T-T autologous mixed lymphocyte reaction.

In this study we have demonstrated that in the T-TA autologous mixed lymphocyte reaction (AMLR), OKT4+ T cells are the major responders; however, in the presence of additional interleukin-2 (IL-2), OKT8+ T cells also respond by proliferation. Both OKT4+ and OKT8+ T cells, activated in the T-non-T AMLR, act as stimulators in the T-TA AMLR. OKT4+ T cells activated in the T-TA AMLR suppress the proliferative response of the fresh T-non-T AMLR; control OKT4+ cells show no immunoregulatory activity in this system. In contrast, control OKT8+ T cells spontaneously suppress the proliferation of the T-non-T AMLR, but activation of OKT8+ T cells in the T-TA AMLR does not result in a further increase in the suppressor activity of OKT8+ T cells. In summary, in the T-non-T and T-TA AMLR phenotypically similar T-cell subpopulations proliferate but express distinct immunoregulatory functions and perhaps regulate the tempo of the AMLR.

Antibodies, Monoclonal↗
PubMed1985

Incorporation of (35S)sulfate and (3H)glucosamine into glycoaminoglycans in rat incisor predentine and dentine: comparison by autoradiography of fixation by rapid-freezing, freeze-substitution, and aldehyde fixation.

At 4 and 24 hours after injection of (35S)sulfate, there were 22-67% fewer silver grains on conventionally fixed sections than on sections fixed by cryotechniques. Differences were smaller when (3H) glucosamine was chosen as precursor. The number of silver grains increased between 4 and 24 hours in predentine and in a 30-micron band of dentine that had already undergone mineralization. Only a few grains were observed, however, in the 5-micron dentine band located at the mineralization front. This suggests that glycoaminoglycans, which in predentine have a space-filling role, facilitate transport and diffusion and inhibit mineralization, may limit crystal growth in dentine once a certain degree of apatite formation has been reached. All these properties are correlated with the structural and functional properties of the tissues.

Aldehydes↗
PubMed1985

Improved lipid preservation by malachite green-glutaraldehyde fixation in rat incisor predentine and dentine.

A network of granules and filaments stained with malachite green-aldehyde (MGA) was observed in predentine in the spaces between the collagen fibres and many small granules were associated with these fibres in peripheral and circumpulpal-dentine. The granules were present throughout the entire thickness of the dentine, especially at the periphery of the calcospherites, although scarce or absent at their centre. This MGA-stainable material (i) resisted demineralization in acetic acid and EDTA solutions, and (ii) differed from non-collagenous material and crystal ghosts which stained on control sections after prior demineralization. In predentine, transport and diffusion of MGA-stainable material occurred in the direction of the dentine in which this material was associated with periodical striation of mineralized collagen fibres. This suggests that true matrix-associated lipids might play a role in dentine mineralization.

Aldehydes↗
PubMed1985

The problem of multiple inference in studies designed to generate hypotheses.

Epidemiologic research often involves the simultaneous assessment of associations between many risk factors and several disease outcomes. In such situations, often designed to generate hypotheses, multiple univariate hypothesis-testing is not an appropriate basis for inference. The number of true positive associations in a collection of many associations can be estimated by comparing the observed distribution of p values for the positive associations to a theoretical uniform distribution, or to the observed distribution of negative associations, or to an empiric randomization distribution. None of these approaches, however, will distinguish the true from the false positive associations. Various criteria for selecting a subset of associations to report are considered by the authors, including Bonferoni adjustment of p values, splitting the sample for searching and testing, Bayesian inference, and decision theory. The authors prefer an approach in which all associations in the data are reported, whether significant or not, followed by a ranking in order of priority for investigation using empirical Bayes techniques. Methods are illustrated by application to preliminary data from a study aimed at identifying hitherto unsuspected occupational carcinogens.

Bayes Theorem↗
PubMed1985

Strangulated congenital diaphragmatic hernia in infants.

Two previously healthy children, 7 and 12 months old, respectively, presented with respiratory distress and severe sepsis. Chest x-rays were suggestive of inflammatory disease of the left lung. At operation, necrotic bowel was found to be herniated through a left congenital posterolateral diaphragmatic hernia. These patients illustrate the difficulty in establishing the diagnosis of strangulated congenital diaphragmatic hernia and the grave consequences when operation is delayed.

Age Factors↗
PubMed1985

A new microsample grinding technique for quantitative determination of calcium and phosphorus in dental enamel.

A new microsampling method is described for measuring variations in calcium and phosphorus distribution in dental enamel. Ten successive layers, 10 micron thick, from five human enamel posts with previously abraded flat upper surfaces were ground and analyzed. Mean Ca and P values were, respectively, 1116 +/- 110 and 527 +/- 47 micrograms/mm3, and mean Ca/P w/w and molar ratios, 2.11 +/- 0.10 and 1.63 +/- 0.08, respectively. Despite its limitations, the present method allows for accurate investigation of the mineral content in sound, experimentally-treated enamel.

Calcium↗
PubMed1985

Relief of morning stiffness: a comparative study of naproxen and ibuprofen.

Morning stiffness in 75 patients with mild to moderate rheumatoid arthritis was treated with 1600 mg ibuprofen 4-times daily or 750 mg naproxen twice daily after a placebo-induced flare of this symptom. With the final daily dose of each drug administered at bedtime, both drugs significantly reduced the duration and severity of morning stiffness compared to baseline values but, on average, duration of morning stiffness tended to be shorter for naproxen patients than for ibuprofen patients. No corresponding between-drug difference was found for severity of morning stiffness.

Adolescent↗
PubMed1985

Effects of alpha-2 agonists on renal function in hypertensive humans.

Centrally acting adrenergic agonists, by decreasing peripheral adrenergic activity, are effective antihypertensive agents. The older agents, however, especially methyldopa, have been associated with weight gain, clinical edema, and antihypertensive tolerance when used as monotherapy. While acute studies in humans have demonstrated weight gain and sodium retention with clonidine and guanabenz, chronic administration results in a decrease in weight and plasma volume. The absence of chronic weight gain and of sodium retention could be the result of a counterbalance between hypotension-related antinatriuresis, secondary to a decrease in glomerular filtration rate and renal blood flow, and natriuretic activity, as a result of a decrease in renal sympathetic tone. Whereas natriuresis and water diuresis have been demonstrated in animals with acute clonidine or guanabenz administration, this has not been demonstrated in humans. Recent studies in which saline administration was used to precondition humans to a subsequent natriuretic stimulus (i.e., guanabenz-induced decreased renal adrenergic activity) resulted in stabilization of renal blood flow and natriuresis. Selective reduction renal sympathetic activity affecting salt and water transport may explain why guanabenz and probably also clonidine seem to be devoid of the sodium/fluid-retaining properties that are common with other antihypertensive agents. Because agents of this class have effects other than pure central alpha-2 agonism (such as alpha-1 activity), they might have confounding and counterbalancing side effects leading to sodium and water retention.

Adrenergic alpha-Agonists↗
PubMed1985

Intramembrane particle distribution on the plasma membrane of ruffle-ended and smooth ended maturation ameloblasts of the rat incisors.

Plasma membrane structure and intramembrane particle (IMP) distribution in ruffle-ended (RA) and smooth-ended (SA) maturation ameloblasts were investigated by means of freeze-fracture replication of the rat incisor enamel organ. On the plasma membranes of both the lateral and distal cell surfaces, mean values of IMPs per 1 micron2 obtained from the SAs were lower than that from the RAs. This does not exclude the ameloblast modulation phenomenon but rather supports a radical shift of functional activity between RA and SA and argues in favour of the possible existence of two definite groups of maturation ameloblasts. In the distal plasma membranes of these ameloblasts, there were also some morphologic evidence of endocytic activity (resorptive functions).

Ameloblasts↗
PubMed1985

Immunoprecipitation analysis of radiolabelled protein antigens biosynthesized in vitro by S. mansoni. I. Identification of antigens uniquely recognized by protective antibodies.

Protein antigens from 4-wk worms were metabolically radiolabelled with [3H]leucine or [35S]methionine. Three freeze-thaw cycles released a large proportion (50% to 60%) of the TCA-precipitable radioactivity from the worms. Immune serum from twice-infected Fischer rats (F-2x), which was shown to confer resistance in a passive immunization assay, and immune serum from twice-infected Wistar Furth rats (W-2x), which does not confer resistance, were used for analyzing antigens in this worm fraction. Antibodies in these antisera differed in their titers to the freeze-thaw released antigens (W-2x greater than F-2x) and in their relative affinities for these antigens (F-2x greater than W-2x). Gradient slab gel electrophoresis of immunoprecipitates of radiolabelled antigens under denaturing conditions revealed many components, which could be categorized into two main types: unique antigens, recognized only by F-2x antibodies, and nonunique antigens, recognized by both F-2x and W-2x antibodies. The potential relevance of these antigens in resistance was further examined by antibody absorption experiments in which 4-wk worms were used as an immunoabsorbent to remove 90% to 95% of the immunoprecipitating activity and 65% to 70% (p less than 0.005) of the capacity to confer resistance in a passive immunization assay. It was concluded that loss of both anti-schistosome activities was specific since antigen released by worms during absorption could account for only 16% of the reduction in antigen-binding capacity and the titer of antibodies directed against beta-galactosidase did not significantly change during absorption. Antigens recognized uniquely by F-2x antibodies are therefore candidates for immunization studies examining induction of resistance against Schistosoma mansoni.

Absorption↗