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Biomedical subjects

C Steinberg

Publications and source records attributed to C Steinberg.

45 records · Page 3Linked to original sources
PubMed1984

Immunologic studies on the induction of diabetes in experimental animals. Cellular basis for the induction of diabetes by streptozotocin.

Repeated low doses of streptozotocin (STZ, 40 mg/kg body wt) gradually induce hyperglycemia in mice after a latent period of 5-7 days. The ability of STZ to induce hyperglycemia varies in different mouse strains. Repeated low doses of STZ fail to induce diabetes in T-cell-deficient mice, suggesting a crucial role of T-cells in the induction of diabetes by this procedure. Transfer of spleen cells from mice rendered diabetic by repeated low doses of STZ failed to induce hyperglycemia in the recipients. However, pretreating the recipients with a single low dose of STZ permitted efficient transfer of the diabetic state, suggesting that the immunologic reaction resulting in diabetes was actually specific for an STZ-modified beta cell.

Animals↗
PubMed1984

A metrological study of autoradiographs from two-dimensional gel electrophoresis.

Samples prepared from a single batch of labeled cells were subjected to two-dimensional gel electrophoresis and autoradiography. Three factors were varied: total quantity of protein, quantity of labeled protein, and exposure time. The mean background absorbance of the film remained identical (about 0.5 A) for all the treated series, whatever the exposure time and whether or not there were unlabeled proteins in the sample. Hence any spot with a peak A of the same order of magnitude can be seen. The standard deviation was about 0.05 A. Thus, the measurement precision is 2.5% of full scale for digitalization over 0 to 2 A. We derived experimental calibration curves, which are neither linear nor logarithmic because of the film response and which can be used on randomly chosen spots.

Animals↗
PubMed1982

A theory of allelic and isotypic exclusion for immunoglobulin genes.

Heavy (H) chain binding protein (BiP), which binds to free immunoglobulin H chain of the mu and gamma classes, can be demonstrated in pre-B-cells. It is proposed that the displacement of BiP from H chain by light (L) chain terminates the activity of the enzyme system, L-generase, which catalyzes DNA rearrangement at the L chain loci, generating the complete gene which may or may not be functional. This ensures allelic and isotypic exclusion for the L chain loci. It is further proposed that those cells that productively rearrange both alleles at the H chain locus are eliminated by the "H chain toxicity" effect.

Alleles↗
PubMed1974

Evidence for somatic generation of antibody diversity.

RNA preparations containing 70-80% mouse kappa-chain mRNA have been prepared. The remainder consists of many RNA species, each of which represents a small fraction of the total RNA. The kappa-chain mRNA preparation hybridizes with mouse liver DNA with bi-phasic kinetics, indicating that it consists of two fractions -"unique" and "reiterated." Competition hybridization experiments show that the homology among the unique fractions from different mRNAs is the same as the homology among the amino acid sequences of the corresponding kappa-chains. Hence, in addition to the C-region (constant-region) sequences, (most of) the V-region (variable-region) sequences are also derived from unique germ line genes. The reiterated fractions from different kappa-chain mRNAs show essentially complete homology with each other. This fraction seems to consist mostly of sequences which do not code for amino-acid sequences of the secreted polypeptide chain, i.e., the "external" section of the mRNA molecule. It is concluded that the number of germ line genes is too small to account for the observed diversity of antibody molecules.

Amino Acid Sequence↗
PubMedDate not supplied

Obese women's perceptions of their physicians' weight management attitudes and practices.

BACKGROUND: Obesity has reached epidemic proportions in the United States. Primary care physicians will see increasing numbers of patients with long-term weight management problems. OBJECTIVE: To examine obese women's perceptions of their physicians' weight management attitudes and practices. DESIGN AND SETTING: Women who participated in obesity trials at a university clinic completed a questionnaire that assessed their views of weight control provided by their primary care physician. PARTICIPANTS: The patients were 259 women whose age was 44.0 +/- 10.0 years; weight, 96.7 +/- 13.2 kg; and body mass index (calculated as weight in kilograms divided by the square of height in meters), 35.2 +/- 4.5 (all data given as mean +/- SD). MAIN OUTCOME MEASURES: Using 7-point scales (1 indicates low; and 7, high), patients rated their satisfaction with care provided for their general health and that for their obesity. They also identified methods their physician recommended for weight management and the frequency of negative interactions with their physician concerning weight control. RESULTS: Participants were generally satisfied with the care they received for their general health and with their physicians' medical expertise (mean scores, 6. 1 and 6.2, respectively). They were significantly (P<.001) less satisfied with care for their obesity and with their physicians' expertise in this area (mean scores, 4.1 and 4.3, respectively). Almost 50% reported that their physician had not recommended any of 10 common weight loss methods, and 75% indicated they looked to their physician a "slight amount" or "not at all" for help with weight control. Only a small minority of patients (0.4%-8.0%) reported frequent, negative interactions with physicians concerning their weight. CONCLUSIONS: The last finding helps allay concerns that obese patients are routinely treated disrespectfully by physicians when discussing weight. The challenge, however, for primary care physicians appears to be providing patients better assistance with weight management.

Adult↗