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Biomedical subjects

S M Russell

Publications and source records attributed to S M Russell.

At least 127 records · Page 7Linked to original sources
PubMed1979

Coordination of protein synthesis and degradation.

The degree of coordination between protein synthesis and protein degradation in developing and mature cels is considered. Studies on specific enzyme and general protein turnover in developing liver and differentiating mammary gland are presented. In the mature liver mitochondrion average protein degradation rates are higher for outer membrane and intermembrane space proteins than for matrix and inner membrane proteins. Significant heterogeneity of protein degradation rates was observed only in the outer mitochondrial membrane. During postnatal development the rates of degradation of proteins in many liver cellular fractions are increased. In the mitochondrion only the average rates of degradation of proteins in the outer membrane and intermembrane space fractions increase during development. Evidence for hormonally regulated changes in both protein synthesis and degradation during mammary cell differentiation is given. The data indicate that a transitory decrease in protein degradation accompanies the increase in protein synthesis on hormonal stimulation of the tissue. The results from the two model systems are collated and used to formulate a phenomenological hypothesis of protein degradation and its integration with protein synthesis in steady-state and non-steady-state conditions.

Animals↗
PubMed1978

Heterogeneity in horse ferritins. A comparative study of surface charge, iron content and kinetics of iron uptake.

Horse ferritins from different organs show heterogeneity on electrofocusing in Ampholine gradients. Both ferritin and apoferritin from liver and spleen could be fractionated with respect to surface charge by serial precipitation with (NH4)2SO4. In the ferritin fractions, increasing iron content parallels increasing isoelectric point. After removal of their iron, those fractions which originally contained most iron accumulated added iron at the fastest rates. When unfractionated ferritins from different organs were compared the average isoelectric point increased in order spleen less than liver less than kidney less than heart. The order of initial rates of iron uptake by the apoferritins was spleen greater than kidney greater than heart and initial average iron contents also followed this order. The relatively low rates of iron accumulation by iron-poor molecules may have been due to structural alteration, to degradation, to activation of the iron-rich molecules or to other factors.

Animals↗
PubMed1978

Differential effects of elevated potassium ion concentration and of theophylline on growth hormone release by rat adenohypophyses in vitro.

The effects of 27 mM K+ and of 6.7 mM theophylline on the release of growth hormone (GH) by rat hemipituitaries in vitro were investigated using bioassay (rat tibia test) and radioimmunoassay (RIA). Both agents markedly increased the release of immunoreactive GH. High K+ also promoted the release of bioactive GH but to a much lesser degree than RIA-GH. Theophylline did not consistently affect the release of bioassay-detectable GH. The results suggest that these agents promote massive release of a form of immunoreactive GH (possibly "immature") that has little or no activity in the bioassay. Theophylline is relatively more effective in this regard than is elevated K+.

Animals↗
PubMed1978

Evaluation of the single radial haemolysis (SRH) technique for rubella antibody measurement.

Sera from 1258 individuals have been tested by four laboratories for rubella antibody by both the haemagglutination-inhibition and single radial haemolysis techniques. There was good agreement between the results obtained by the two methods. Although sheep red blood cells were used in the single radial haemolysis plates, no problems were encountered with sera from patients with infectious mononucleosis. The single haemolysis technique was found to be simple, convenient, and reliable, and suited to the rapid screening of large numbers of sera to assess susceptibility to rubella in the context of a vaccination campaign. However, since the technique does not detect anti-rubella IgM, it should not be used as the only test to investigate suspected recent infection.

Antibodies, Viral↗
PubMed1978

Electrophoretically separable forms of rat prolactin with different bioassay and radioimmunoassay activities.

The possible existence of forms of rat PRL with different bioassay (BA)/RIA activity ratios was investigated. Anterior pituitary tissue and medium in which explants of rat adenohypophyses had been incubated were processed by polyacrylamide disc gel electrophoresis using a Tris-glycine buffer. The gel columns were cut into five segments and eluates from these were tested for PRL by BA and by RIA. Most of the BA- and RIA-detectable PRL in tissue and medium was found in the same gel region to which purified rat PRL (RP-1) migrated. The BA/RIA ratio of this major form of PRL was 2.2-4.0. Other more slowly migrating forms of PRL were found in the regions where albumin and growth hormone migrate. The BA/RIA activity ratios of these forms varied depending on the sample processed (e.g., tissue vs. medium; sex and/or age of the adenohypophyseal donor; duration of incubation) but were generally considerably higher than those of the respective major forms. PRL that migrated faster than the major form was also detected by the RIA in several cases, but in only one experiment (with 4-day culture medium) was bioassayable PRL present in this more anodal region. In this case the BA/RIA ratio was very high (78.6). These results indicate that forms of rat PRL with different BA/RIA activity ratios exist within and are secreted by rat adenohypophyses.

Aging↗
PubMed1978

Relationship between bioassay and radioimmunoassay estimates of prolactin in rat serum.

RIA and bioassay (BA) estimates of the concentration of PRL ([PRL]) in rat serum were compared using homologous assay systems. A rat mammary gland organ culture BA was developed which allowed objective and quantitative measurement of serum [PRL]. the serum samples were tested at two doses against three doses of the RP-1 rat PRL standard and the responses were quantified by a histometric procedure. The index of precision of the BA ranged from 0.1--0.4 and the secretory response was not affected by physiological concentrations of rat GH, T3, or by gonadal steroids. Serum samples taken from female rats during the estrous cycle, from suckled lactators, from rats bearing a PRL-secreting pituitary tumor, and from females that were treated with perphenazine were assayed. A highly significant correlation (r = 0.99) was obtained between the two assay methods with 21 samples. However, the regression coefficient was 4.20 +/- 0.55.Thus, although the two assays are highly correlated for measuring serum [PRL], the RIA measures only about 25% of the hormone that is detected by the mammary gland organ culture BA.

Animals↗
PubMed1976

Comparison of secreted and extracted forms of rat pituitary prolactin.

Prolactin secreted by rat anterior pituitary explants into organ culture medium was purified by salt fractionation and gel filtration. A yield of 22 mg/g was obtained, which clearly represented de novo synthesis and secretion of the hormone. Comparative characterization studies were performed on the secreted prolactin and pituitary extracted rat prolactin obtained from the National Institute of Arthritis, Metabolism and Digestive Disease. The biological and immunological activity estimates of both forms were comparable, although the specific activities of the secreted prolactin were somewhat lower than those of the pituitary prolactin. The secreted and extracted forms of prolactin appeared to be identical in primary structure as evidenced by similar amino acid compositions and identical NH2-terminal sequences. Circular dichroism spectra suggested that there may be differences in tertiary structure, since the positive tryptophan band at 292 nm, which eas observed with extracted hormone, was absent in the secreted prolactin.

Amino Acids↗
PubMed1975

A single radial haemolysis technique for the measurement of influenza antibody.

A single radial haemolysis in geltechnique has been developed for the detection and measurement of antibody to influenza haemagglutinin. The methold combines the sensitivity of haemagglutination-inhibition with the accuracy of single radial diffusion. It is simple, quick, reproducible, does not require purified or concentrated virus, and is unaffected by non-specific inhibitors. The method is particularly suitable for the routine screening of large numbers of serum samples, and may have application also to viruses other than the influenza group.

Animals↗
PubMed1975

Measurement of parainfluenza-3 virus antibody by the single radial hemolysis technique.

A single radial hemolysis assay for parainfluenza-3 virus antibody is described as a simple, sensitive, accurate, and precise alternative to hemagglutination inhibition and serum neutralization tests. A highly significant correlation exists between single radial hemolysis zone areas and hemagglutination inhibition titers of both serum and nasal secretion samples. Antibody conversions equivalent to as little as a twofold rise in hemagglutination inhibition titer are readily and reliably detected in sera and nasal secretions. Single radial hemolysis and hemagglutination inhibition activity was demonstrable in the immunoglobulin G fraction of a hyperimmune parainfluenza-3 virus antiserum.

Animals↗
PubMed1971

The Australia (hepatitis-associated) antigen in fibrinogen and other fractions of human plasma.

Human plasma containing the Australia (hepatitis-associated) antigen was fractionated by the cold ethanol method of Cohn, Strong, Hughes, Mulford, Ashworth, Melin, and Taylor (1946) and small aliquots were examined for the presence of this antigen by immunodiffusion and by electron microscopy. The findings were in general agreement with the postulated risk of transmitting hepatitis by blood derivatives. The Australia (hepatitis-associated) antigen was detected in fibrinogen, thrombin, and antihaemophilic globulin as well as in other fractions. The antigen was not found in gamma globulin (immunoglobulin fraction) nor in albumin.The use of radioiodinated fibrinogen for the diagnosis of deep vein thrombosis is discussed and it is concluded that the use of fibrinogen for diagnostic procedures should be assessed against the possible risk of hepatitis.

Factor VIII↗