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Biomedical subjects

B Weissman

Publications and source records attributed to B Weissman.

At least 37 records · Page 2Linked to original sources
PubMed1988

The calcium signal for BALB/MK keratinocyte terminal differentiation counteracts epidermal growth factor (EGF) very early in the EGF-induced proliferative pathway.

BALB/MK mouse epidermal keratinocytes require epidermal growth factor (EGF) for proliferation and terminally differentiate in response to high calcium concentrations. We show that EGF is an extremely potent mitogen, causing BALB/MK cultures to enter the cell cycle in a synchronous manner associated with a greater than 100-fold increase in DNA synthesis. Analysis of the expression of proto-oncogenes which have been reported to be activated during the cascade of events following growth factor stimulation of fibroblasts or lymphoid cells revealed a very rapid but transient 100-fold increase in c-fos RNA but little or no effect on the other proto-oncogenes analyzed. Exposure of EGF-synchronized BALB/MK cells to high levels of calcium was associated with a striking decrease in the early burst of c-fos RNA as well as the subsequent peak of cell DNA synthesis. Since the inhibitory effect of high calcium on c-fos RNA expression was measurable within 30 min, our studies imply that the EGF proliferative and calcium differentiation signals must interact very early in the pathway of EGF-induced proliferation. Our results also establish that c-fos RNA modulation is an important early marker of cell proliferation in epithelial as well as mesenchymal cells.

Animals↗
PubMed1987

Behavioral studies with anxiolytic drugs. IV. Serotonergic involvement in the effects of buspirone on punished behavior of pigeons.

Interactions of the nonbenzodiazepine anxiolytic, buspirone, with serotonin (5-HT) were studied using behavioral and neurochemical procedures. Punished responding was studied in pigeons as this behavior is a generally acknowledged preclinical predictor of anxiolytic activity and because buspirone increases punished responding of pigeons with greater potency and efficacy than in other species. Keypeck responses were maintained under either fixed-interval or fixed-ratio schedules of food presentation; every 30th response produced a brief electric shock and suppressed responding (punishment). Buspirone (0.1-5.6 mg/kg i.m.) produced dose-related increases in punished responding which reached a maximum at 1 mg/kg. A serotonin agonist, MK-212 (0.01 mg/kg), antagonized whereas the 5-HT antagonist, cyproheptadine (0.01 mg/kg), potentiated the effects of buspirone without having behavioral effects of their own. The characteristics of [3H]-5-HT binding in pigeon brain membranes were similar to results reported in mammalian brain. Neither buspirone, MJ-13805 (gepirone, a related analog), nor MJ-13653 (a buspirone metabolite), significantly affected [3H]-5-HT binding and none of the compounds appreciably inhibited uptake of [3H]-5-HT into pigeon cerebral synaptosomes. Hill coefficients significantly less than unity for all drugs except 5-HT suggested multiple serotonergic binding sites for buspirone and analogs. Buspirone and MJ-13805 (1 nM) inhibited [3H]ketanserin binding (a measure of 5-HT2 binding sites) in pigeon cerebrum with Ki values above 10(-6) M. The number of [3H]ketanserin binding sites was estimated to be 109 fmol/mg of protein in pigeon cerebrum compared to 400 fmol/mg of protein in rat cerebrum.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1985

Members of the src and ras oncogene families supplant the epidermal growth factor requirement of BALB/MK-2 keratinocytes and induce distinct alterations in their terminal differentiation program.

BALB-/MK-2 mouse epidermal keratinocytes required epidermal growth factor for proliferation and terminally differentiated in response to high Ca2+ concentration. Infection with retroviruses containing transforming genes of the src and ras oncogene families led to rapid loss of epidermal growth factor dependence, in some cases, accompanied by alterations in cellular morphology. The virus-altered cells continued to proliferate in the presence of high levels of extracellular calcium but exhibited alterations in normal keratinocyte terminal differentiation that appear to be specific to the particular oncogene. These alterations bore similarities to abnormalities in differentiation observed in naturally occurring squamous epithelial malignancies.

Animals↗
PubMed1981

Observations on maternal preference for rooming-in facilities.

To determine the length of time mothers prefer their infants with them, 1,000 mothers at North Shore University Hospital (NSUH) and 435 mothers at Kings County Hospital (KCH) were asked postpartum whether they would prefer their infants with them every four hours for 1/2 hour for feeding or rooming-in with their infants during the daytime only or 24 hours a day. Approximately one third of the mothers at NSUH preferred rooming-in whereas approximately three quarters of the mothers at KCH preferred rooming-in. Significantly more mothers at KCH preferred 24-hour rooming-in than at NSUH. Factors such as primiparity, attendance at Lamaze classes, and breast-feeding were significantly associated with the mother's preference to room-in at NSUH, but there was no such association at KCH. This study suggests that: (1) the desire to room-in is not universal; (2) each institution must individualize rooming-in facilities according to the needs of the population; (3) although the demand for rooming-in varies, more mothers prefer rooming-in than there are accommodations presently available; and (4) factors that may be associated with rooming-in are not the same in all populations. It appears that it is as inappropriate to impose rooming-in as it is to deprive mothers of rooming-in.

Black or African American↗
PubMed1980

Conservation surgery of the larynx.

The goal of conservation surgery of the larynx is to maintain the protective, respiratory, and phonatory function of that organ while completely removing the malignant disease. Thirty-two patients with endolaryngeal invasive squamous cell carcinoma treated by this method between 1958 and 1967 are evaluated. Our cure rate of 91% by conservation surgery attests to the efficiency of this therapy.

Arytenoid Cartilage↗
PubMed1980

Characterization of ouabain resistant, hypoxanthine phosphoribosyl transferase deficient human cells and their usefulness as a general method for the production of human cell hybrids.

Ouabain resistant mutants of hypoxanthine phosphoribosyl transferase deficient HeLa cells and euploid human fibroblasts were isolated and extensively characterized. These double mutants were used to test the prediction that they would be "universal hybridizers" for intraspecific human cell hybrid production. Hybrids were selected from fusions with human cells of diverse somatic origin. In addition it was shown that multiparental hybrids can be generated using a modification of the selection system, a result which will be useful for gene dosage experiments involving human cells.

Adenosine Triphosphatases↗
PubMed1977

Marginal aberrations of different bifocal-lens designs.

Marginal astigmatism and longitudinal chromatic aberration were measured (with a modified Vertometer) for +2-D bifocal lenses of different designs, base curves, and major-lens powers. At a reading level 20 deg below the pole of the major lens, deterioration of the optical image occurred and was created by the interaction of marginal astigmatism (tangential error) and lateral chromatic aberration (prismatic dispersion). Suggestions for selecting an optimal bifocal-lens design for different types of refractice error are presented.

Lenses↗
PubMed1975

Concerted action of beta-glucuronidase and beta-acetylglucosaminidase on hyaluronodextrins.

A kinetic analysis of the stepwise alternating action of beta-glucuronidase and beta-acetylglucosaminidase on oligosaccharides and dextrins derived from hyaluronic acid was undertaken, for better definition of the contribution of this process to hyaluronate catabolism. Production of monosaccharide from larger dextrins by action of either enzyme is powerfully inhibited by electrolyts. In the study, as in mammalian tissues, beta-glucuronidase is present in excess so that the concentration of beta-acetylglucosaminidase is rate controlling in the action on dextrin substrates. For this action, Vmax shows limited variation with ionic strength or molecular weight of substrate. At ionic strength 0.03, but not 0.18, Km decreases some 100-fold for increase of molecular weight from 2,000 to 15,000. It is specifically this decrease in Km that accounts for the prominent electrolyte inhibition observed with larger dextrins. The extremely low values of Km are attributed to multiple ionic enzyme-substrate interactions at sites remote from the catalytic center. The previously reported stimulation by electrolyte of the action of beta-glucuronidase and beta-acetylglucosaminidase on aryl glycosides, studied briefly, is apparently unrelated to the electrolyte effects seen with dextrins. The catabolic contribution of beta-glucuronidase and beta-acetylglucosaminidase appears to be restricted to hydrolysis of the smaller oligosaccharides produced by action of hyaluronidase, since, for any reasonable assumptions regarding cellular environment, the extent of their action on polymeric hyaluronate or larger dextrins must be limited.

Acetylglucosaminidase↗