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Biomedical subjects

C S Rubin

Publications and source records attributed to C S Rubin.

At least 91 records · Page 5Linked to original sources
PubMed1982

Insulin activates a tyrosine-specific protein kinase in extracts of 3T3-L1 adipocytes and human placenta.

Insulin activates a tyrosine-specific cAMP-independent protein kinase when added directly to detergent extracts of differentiated 3T3-L1 adipocytes and humal placental membranes. The kinase is also activated by antibody to the insulin receptor and, to a lesser extent, by proinsulin. It catalyzes the phosphorylation of the 92,000-dalton component of the insulin receptor, histone, and casein; in each case, tyrosine is the principal amino acid modified. Under the conditions used to activate the kinase, insulin does not affect the rate of dephosphorylation of the receptor or of histone. The insulin-activated kinase is copurified with the human placental insulin receptor until the final elution from insulin-Sepharose. It remains to be established whether the kinase and the insulin receptor are separate molecules.

Adipose Tissue↗
PubMed1982

Clinical experience with a prototype real-time dedicated breast scanner.

The evaluation of 1,003 sonomammographic examinations on a predominantly symptomatic population using a prototype real-time dedicated breast scanner is presented. Interpretations were initially made by one of four experienced radiologists without knowledge of clinical data (i.e., symptoms, age, physical findings, or other imaging modality interpretations). A second interpretation was subsequently made with this information. Pathologic confirmation was available on 262 lesions, including 71 carcinomas and 191 benign biopsies. Of the carcinomas, 19 were smaller than 2.0 cm in diameter. The sensitivity of sonographic detection of breast cancer on initial readings was 0.76 and on second readings with clinical data was 0.85. The specificity for a benign reading on sonography was 0.80 on initial interpretation and 0.81 on the second interpretation.

Adolescent↗
PubMed1981

Purification and properties of the human placental insulin receptor.

Human placenta insulin receptor was purified 11,000-fold to near homogeneity using DEAE-cellulose chromatography and affinity chromatography on insulin-Sepharose. Approximately 200 to 300 micrograms of purified receptor were obtained from a single placenta. In solution, the native receptor is a complex (Mr = 440,000) of an acidic, multi-subunit protein with a Mr of 350,000 and bound detergent accounting for the remainder of the mass. The receptor protein is asymmetric (f/f0 = 1.4) and consists of a single Coomassie blue staining polypeptide of Mr = 135,000. In addition to the 135,000-dalton polypeptide, two smaller polypeptides of Mr = 45,000 and 90,000 were observed upon autoradiography of 125I-labeled receptor subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These two smaller polypeptides did not stain with Coomassie blue but migrated with native receptor activity on isoelectric focusing gels and were coimmunoprecipitated with the 135,000-dalton polypeptide by anti-insulin receptor antibody. The 135,000-dalton subunit was specifically labeled by 125I-insulin using the bifunctional cross-linking reagent disuccinimidyl suberate (P. F. Pilch, and M. P. Czech, (1979) J. Biol. Chem. 254, 3375-3381), suggesting that this component contains the insulin binding domain.

Binding, Competitive↗
PubMed1981

Insulin stimulates the phosphorylation of ribosomal protein S6 in a cell-free system derived from 3T3-L1 adipocytes.

Physiological concentrations of insulin stimulate the incorporation of 32P into ribosomal protein S6 in intact 3T3-L1 adipocytes (Smith, C. J., Wejksnora, P. J., Warner, J. B., Rubin, C. S., and Rosen, O. M. (1979) Proc. Natl. Acad. Sci. U. S. A. 76, 2725-2729). Extracts from cells treated with insulin also exhibit an increased ability to incorporate 32P from [gamma-32P]ATP into protein S6 in vitro (Smith, C. J., Rubin, C. S., and Rosen, O. M. (1980) Proc. Natl. Acad. Sci. U. S. A. 77, 2641-2645). We now report that the direct addition of insulin to particulate preparations containing high affinity insulin receptors and ribosomes derived from insulin-sensitive cells (not previously exposed to insulin) stimulates incorporation of 32P from [gamma-32P]ATP into ribosomal protein S6 1.5- to 3.0-fold. The stimulation occurs at the same concentrations of insulin (0.1-1.0 nM) and within the same period of time as it does in intact cells.

Adipose Tissue↗
PubMed1981

Genetic control of insulin receptors.

Insulin-binding activity was measured in hepatocyte suspensions and liver membrane preparations from newborn mice homozygous for a perinatal-lethal deletion at and around the albino locus in chromosome 7. Cell suspensions and membrane preparations from the mutant mice exhibited only 20-25% of the specific hormone-binding activity observed in comparable preparations from their homozygous normal and heterozygous littermates. The decrease in insulin-binding activity appears to be attributable to a decrease in the number of insulin receptor sites per cell rather than to a change in receptor affinity. Gene sequences deleted at and around the albino locus are therefore instrumental in the regulation of insulin receptor concentration rather than in coding for the insulin receptor itself. The results of the present studies extend the identification of the regulatory functions exerted by the genes around the albino locus of the mouse.

Animals↗
PubMed1981

Ultrasound mammography: a comparison with radiographic mammography.

The results of 1,029 ultrasound B-scan examinations of the breast using two automated water-path scanners were correlated with histopathology data in 278 patients who had undergone biopsy. Of the 1,029 patients, a subgroup of 709 patients had both ultrasound mammograms (USM) and radiographic mammograms (XRM) obtained. A sensitivity for breast cancer of 69% was found for USM and 74% for XRM on initial independent readings when there was no knowledge of clinical data. These are not statistically different using the McNemar test for paired comparisons. When the USM were reinterpreted with the knowledge of the patient's age, history, physical examination, and, when available, the XRM interpretation, the USM sensitivity for breast cancer was 79%.

Adolescent↗
PubMed1981

Echogenicity: analysis, significance, and masking.

Echogenicity can be created by the admixture of any acoustically dissimilar substances. Experiments performed in vitro using mineral oil and water and in vivo examining 24 pathologically proven echogenic abnormalities show that echogenicity cannot be ascribed to a specific tissue, but rather is a property of all substances. In addition, when dissimilar histologic and pathologic substances have similar echo appearances and are adjacent, they become indistinguishable. This loss of structural definition can be termed the sonographic "masking sign," comparable in masking qualities to the established radiographic "silhouette sign." When this phenomenon occurs, an abnormality can be detected only through displacement of an organ or distortion of its internal anatomy. A thorough understanding of echogenicity and the sonographic masking sign will allow a more accurate evaluation of masses and infiltrating processes.

Humans↗
PubMed1980

Ultrasound criteria for in utero diagnosis of microcephaly.

Microcephaly (small head) is clinically important only if there is concomitant micrencephaly (small brain). Extensive studies on patients in mental institutions have shown that there is close correlation among microcephaly, micrencephaly, and mental retardation when the head is more than three standard deviations below the norm. If the small head is less than two standard deviations below the norm, no strong correlation exists with eigher small brain or mental retardation. High-resolution ultrasound permits imaging of the fetal head in utero, allowing accurate evaluation of head size and detection of intracranial anomalies. The microcephalics detected in utero over a 2-year period form the basis of this series, showing close correlation with the known clinical data on children with microcephaly. An approach to ultrasound detection and evaluation of fetal microcephaly is proposed.

Female↗
PubMed1980

Real-time aspiration-biopsy transducer.

In vitro and in vivo experience with a real-time aspiration-biopsy transducer indicates that the advantage of this instrument is that it permits the examiner to monitor the movement of the structure being aspirated or biopsied, as well as the movements of adjacent organs, while the needle tip is being inserted into the structure. When the needle tip is inserted into the skin, a strong acoustic shadow is produced along the path of the needle, indicating the optimum position for aspiration and biopsy. Within fluid-filled areas the needle tip is imaged consistently. For shadow path of the needle can be consistently observed, but the needle tip is recorded with more difficulty.

Amniocentesis↗
PubMed1980

Analysis of biparietal diameter as an accurate indicator of gestational age.

To date, there have been 25 studies attempting to correlate biparietal diameter and gestational age; of these, 17 meet specific criteria and thus are included in this evaluation. Although all studies have shown an increase in biparietal diameter with advancing gestational age, between 17 wk and term there is a discrepancy of approximately 3 wk. In this evaluation the charts are compared and the variations analyzed. An ideal table is constructed by combining the mean gestational age, calculated from a statistical analysis, and the variation at each millimeter point, determined by comparison of all the studies. It is hoped that this new 90% composite table, which consists of a range of gestational ages in weeks for each biparietal diameter, will not only provide more realistic indications of fetal age but also will serve as a reminder to sonographers, obstetricians, and patients of the relative accuracy and variations of biparietal diameter measurements.

Cephalometry↗