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Biomedical subjects

K Thomas

Publications and source records attributed to K Thomas.

At least 325 records · Page 18Linked to original sources
PubMed1981

[Gonadocrinin-like activity of the peritoneal fluid during the menstrual cycle in the normal female].

Peritoneal fluid formation and composition is under the dependence of the ovarian function. Collection of these fluids was performed by laparoscopy in normal cycling women. After absorption of the steroids, they were tested on monolayer pituitary cell cultures in order to study the influence on gonadotrophin release. LH secretion was stimulated through cell the menstrual cycle without any cycling variations. FSH secretion was also increased, excepted in the immediate post-ovulation period. Thus the Peritoneal fluid contains, as follicular fluid, substances with gonadocrinin- and inhibin-like activity. Gonadocrinin activity was not correlated with estradiol and progesterone levels in serum and peritoneal fluid.

Animals↗
PubMed1981

[The radioimmunological assaying of the luteinizing hormone-releasing hormone (LH-RH) in human beings. A general review (author's transl)].

The authors attempted to work out a synthesis of the known factors about the specifications required for the levels of LH-RH and for finding this hormone in different human biological milieux. Searching for endogenous LH-RH in women, men and children has given very different results. The disparity between the levels that have been found, which are often at the very limits of detection by the methods used, can be explained by the type of specification of the level and by the effects of the biological milieu used and by the breakdown of endogenous LH-RH in the living organism. The conclusion is that the values that have been found up to now are not really reliable and of no great use in human clinical work.

Antibody Specificity↗
PubMed1981

Luteal function after tubal sterilization.

The luteal function in women after tubal sterilization was evaluated and compared with a control group of women of a similar average age. Progesterone measurements and endometrial biopsies were obtained in the midluteal phase (5 to 10 days before the next menstrual period). The group of women who had been sterilized by tubal ligation or electrocoagulation had a significantly lower (P less than or equal to .001) mean midluteal progesterone level (8.5 +/- 6.0 ng/ml) than the group of women who had been sterilized by Hulka-Clemens clips (15.4 +/0 6.3 ng/ml) and the control group (17.2 +/- 4.8 ng/ml). The comparison between these 3 groups on days 19 and 20 and on days 21 and 22 gave the same statistical results. Progesterone levels were lower than 10 ng/ml in 54% of women after tubal ligation or electrocoagulation, whereas such low values were found in only 20% of women after sterilization by Hulka-Clemens clips and in 12% of the women in the control group. A retarded endometrium was observed more frequently in the women who underwent tubal ligation or electrocoagulation than in those who were sterilized by Hulka-Clemens clips. The most likely hypothesis to explain these differences is that sterilization using Hulda-Clemens clips preserves the continuity of the uteroovarian artery.

Body Temperature↗
PubMed1980

Nuclear energy: The accuracy of policy makers' perceptions of public beliefs.

hysical risks. The policy makers' own attitudes were found to be significantly more favorable than those of the total public sample; this was primarily because the policy makers' beliefs about psychological risks made a significantly smaller negative contribution to attitude, and their beliefs about environmental risks made a significantly larger positive contribution. Tkhe policy makers were able to shift their own (personal) responses in the directions indicated by their role-play assignments to reproduce accurately the overall attitudes of the PRO and CON groups on this controversial topic, although there was a tendency to overestimate the positive attitudes of the PRO nuclear public. In terms of the underlying belief dimensions, however, there was a significant faiure to recognize the extent to which issues of psycholo;gical significance contribute negatively to the attitudes of both PRO and CON public groups. The policy makers underestimated the negative value both groups assigned to these risks as well as the extent to which the public believed that nuclear energy would lead to such risks.

Austria↗
PubMed1980

Molecular mechanisms of control of albumin and alphafetoprotein production: a system to study the early effects of chemical hepatocarcinogens.

The cellular mechanism of control of alphafetoprotein (AFP) and albumin (ALB) production during normal and pathologic permissive states is being examined using complementary DNA probes. AFP is the major serum protein for most of fetal life, but normally is produced in very small amounts in the adult. AFP production recurs in the adult during restitutive proliferation of the liver following partial hepatectomy or chemical injury, early after the exposure to chemical carcinogens and in animals with hepatocellular or yolk sac carcinomas. AFP production is roughly proportional in each case examined so far to the amount of mRNA available. On the other hand, there appears to be no difference in the gene number or gene organization in permissive or non-permissive states and there is no evidence of selective degradation of AFP or AFP (and ALB) production is probably at the level of gene transcription. Understanding of how carcinogens act to permit expression of the AFP gene may lead to important insights into carcinogenic mechanisms.

Albumins↗
PubMed1980

Inactivation of coxsackieviruses B3 and B5 in water by chlorine.

The inactivation rates of coxsackievirus B3 (CB3) and B5 (CB5) by chlorine in dilute buffer at pH 6 were very nearly the same and about half that of poliovirus (Mahoney) under similar conditions. Purified CB3, like the poliovirus, aggregated in the acid range but not at pH 7 and above. Purified CB5 aggregated rapidly at all pH values; still, the graph of log surviving infectivity versus time was a straight line. No chlorine inactivation data were obtained with dispersed CB5, for it could be dispersed only by addition of diethylaminoethyl dextran, which would react with the chlorine. Addition of 0.1 M NaCl to the buffer at pH 6 did not influence the aggregation of CB5 or the rate of chlorine action on either of the coxsackie-viruses, but at pH 10 it increased the disinfection activity of OCl- for both viruses roughly 20-fold. Cesium chloride had a similar but smaller effect. KCl was the most active of the three in this respect, making the inactivating effect of OCl- at pH 10 about equal to that of HOCl at pH 6.

Cesium↗
PubMed1980

Relaxin in non-pregnant women during ovarian stimulation.

Around pharmacologically induced ovulation, inconstant immunoreactive plasma relaxin concentrations were observed. Increasing levels appear during HCG or LH-RH induced lutinization. These values remain high as long as the corpus luteum is sustained. These observations may suggest that relaxin has a role during early luteinization and during the non-gestational lifespan of the corpus luteum in women.

Clomiphene↗
PubMed1980

Immunoreactive relaxin-like substance in human seminal plasma.

Large amounts of an immunoreactive relaxin-like peptide were demonstrated in human seminal plasma. The concentrations of this peptide were determined in seven healthy volunteers, and in twenty-eight non-selected male patients seeking advice for sterility. A wide range of immunoreactive relaxin concentrations was observed, varying between 1,240 pg and 73,000 pg of relaxin porcine equivalents per ml of seminal plasma. Given the very special assay medium of seminal plasma, particular attention was paid to the validity of the radioimmunoassay system when applied to this medium.

Fertility↗
PubMed1979

Control of albumin and alpha-fetoprotein expression in rat liver and in some transplantable hepatocellular carcinomas.

Albumin and alpha-fetoprotein production by rat liver and by four selected transplantable hepatocellular carcinomas is compared to the messenger RNA present in these tissues. Albumin and alpha-fetoprotein were measured by radioimmunoassay of serum concentration, immunofluorescence, and in vitro incorporation of labeled amino acids into proteins specifically precipitated by antisera. The number of mRNA molecules per cell was calculated from the hybridization of specific cDNA probes to polysomal mRNA and by translational activity of polysomal RNA in a wheat germ system. The amount of albumin and alpha-fetoprotein produced by the different tissues is directly related to the number of functional mRNA molecules per cell for each protein.

Animals↗
PubMed1979

Changes in expression of albumin and alpha-fetoprotein genes during rat liver development and neoplasia.

Albumin mRNA was isolated and purified from rat liver polysomes by a combination of immunoprecipitation of specific polysomes, poly(U)-Sepharose 4B chromatography, and fractionation of the resulting poly(A)-containing RNA on a sucrose gradient. alpha-Fetoprotein (AFP) mRNA was isolated from Morris hepatoma 7777 by a similar procedure. The purity of the mRNA preparations was determined by analytical gel electrophoresis under denaturing conditions, analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the polypeptides synthesized in a wheat germ cell-free system, and the kinetics of hybridization to cDNA transcribed from albumin mRNA and AFP mRNA. The albumin mRNA possessed a chain length of approximately 2265 nucleotides and the AFP mRNA possesed a length of approximately 2235 nucleotides when examined under stringent denaturing conditions on agarose gels containing 10 mM methylmercury hydroxide. Analysis of poly(A) content by a hybridization assay with [3H]poly(U) revealed the presence in albumin mRNA of a poly(A) region containing approximately 100 adenosine residues. The AFP mRNA preparation was found to contain an average poly(A) tract of approximately 190 bases. Thus, albumin mRNA appears to contain approximately 330 untranslated nucleotides, and AFP mRNA appears to contain a similar number (approximately 285) of noncoding, nonpoly(A) bases. The purified albumin and AFP mRNA's were used as templates for synthesis of full-length cDNA hybridization probes. Both of the probes selectively hybridized to their templates with kinetics expected for single RNA species the sizes of albumin and AFP mRNA. ROt analysis was used to quantitate albumin and AFP mRNA sequences during normal liver postnatal development and liver oncogenesis. The number of polysomal AFP mRNA molecules per liver was found to drastically decrease during the first weeks of postnatal life, concomitant with a decline in the AFP synthetic capacity of the livers and in the serum concentrations of AFP. During this period, the concentration of albumin mRNA molecules per cell in the liver remained at high, approximately constant levels. In Morris hepatoma 7777, the concentration of AFP-specifying sequences was at least 10(3)-fold higher than that found in normal adult liver, whereas the content of albumin nRNA was four- to five-fold lower. These changes in concentration of albumin and AFP mRNA sequences closely correlated with a parallel variation in the specific protein synthetic capacity of the tissues.

Animals↗
PubMed1979

Fetal heart rate in the second stage of labour. Method of interpretation and parameters of the new-born.

The authors present a protocol for the interpretation of the fetal heart rate during the second stage of labour (limited to the last 30 min before delivery). The FHR recordings were grouped according to five classes of increasing pathological significance. Good correlations were obtained between these classifications and the Apgar score as well as the umbilical artery pH.

Apgar Score↗
PubMed1978

Changes in pituitary gonadotropins during the amenorrhoea-galactorrhoea syndrome due to sulpiride.

Sulpiride, a dopamine receptor blocker which raises prolactin, was given to six women with idiopathic amenorrhoea for 10 days and to eleven women with regular cycles for 3 to 6 months. The latter group developed galactorrhoea and amenorrhoea during treatment. Basal LH AND FSH concentrations showed no significant changes. At 3 months but not at 10 days (amenorrhoea group) or 6 months (regular menses group) the area-under-the-curve of LH response to LHRH was increased. FSH responses to LHRH was not altered. The significance of these results to the hyperprolactinaemia-amenorrhoea syndromes are discussed.

Amenorrhea↗