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A K Roy

Publications and source records attributed to A K Roy.

At least 181 records · Page 10Linked to original sources
PubMed1977

Performance evaluation of BK amputees through graded load carrying tests.

The ergonomic approach to performance evaluation in orthopaedic rehabilitation presents problems because of the cumbersome and time-consuming measurement and test procedures involved. This paper describes a method of performance evaluation through graded load carrying tests which makes it possible to set up regression equations which can be used in routine clinical practice for prediction of the performance of below-knee amputees.

Adult↗
PubMed1976

Effect of estrogen on gene expression in the chick oviduct. In vitro transcription of the ovalbumin gene in chromatin.

RNA was transcribed from chromatin isolated from chick oviduct and spleen by using RNA polymerase from Escherichia coli. RNA was also transcribed from whole chick DNA using E. coli RNA polymerase. DNA complementary to ovalbumin messenger RNA (cDNAov) was then used as a hybridization probe to estimate the concentration of ovalbumin messenger RNA sequences (mRNAov) in these in vitro transcripts. Although chromatin from unstimulated chick oviduct was capable of substantial RNA synthesis, no detectable mRNAov sequences could be found in the transcript. Likewise, mRNAov sequences could not be found in RNA synthesized from spleen chromatin using E. coli RNA polymerase. However, chromatin from estrogen-stimulated chick oviducts was capable of supporting synthesis of ovalbumin mRNA. We estimate that approximately 0.01% of the RNA synthesized from estrogen-stimulated chromatin was mRNAov sequences. When RNA synthesized from chick DNA was tested with the cDNAov probe, mRNAov sequences could be detected in a concentration of approximately 10% that found in the RNA transcript from estrogen-stimulated chromatin. This was as expected if the ovalbumin gene is considered to be in the "open or derepressed" region of the estrogen-stimulated oviduct chromatin. Chromatin isolated from chicks withdrawn from hormone for 12 days was only capable of supporting mRNAov synthesis in vitro at a level of 5 to 10% of that observed in chromatin prepared from estrogen-stimulated chicks, thus indicating the requirement for estrogen to maintain the ovalbumin gene in the available or "open" state in the majority of oviduct cells. These data militate against post-transcriptional control as the primary mechanism of steroid hormone regulation of specific mRNA synthesis in the chick oviduct system, and favor primary gene derepression as the most likely mechanism for estrogen induction of ovalbumin synthesis.

Animals↗
PubMed1976

Effect of cyproterone acetate on androgen-dependent synthesis of alpha2u globulin in rats.

Cyproterone acetate (CA, 2-5 mg/100 g body wt) inhibited androgenic induction of alpha2u globulin in spayed rats. In mature male rats, which normally produce alpha2u globulin, ten daily injections of CA did not inhibit synthesis of this protein. Long-term treatment of mature male rats (two injections every week for 12 weeks) showed only slight inhibition of alpha2u synthesis after 10 weeks of CA treatment. CA also failed to compete with 5alpha-dihydrotestosterone for the cytosol androgen-binding protein of male rat liver. The inhibitory effect of CA on the primary induction of alpha2u globulin in the spayed rat and its lack of effect on continued synthesis of this protein in maximally induced mature male rats are consistent with the hypothesis of a two-step mechanism for androgenic regulation of alpha2u synthesis, an initial CA-sensitive step followed later by a CA-insensitive step.

Alpha-Globulins↗
PubMed1975

Hormonal regulation of the hepatic messenger RNA levels for alpha2u globulin.

The messenger RNA rat alpha2u globulin has been identified and quantitated in a cell-free translational system derived from Krebs II ascites cells. Hepatic tissue of the mature male rats which normally produce alpha2u globulin was also found to contain a high level of alpha2u mRNA. Approximately 1.6 per cent of all poly(A) containing RNA of the adult male rat liver could be accounted for alpha2u messenger activity. Female rats do not produce alpha2u globulin and no alpha2u mRNA activity could be detected in the poly(A) containing RNA fraction obtained from the livers of these animals. However, androgen treatment to spayed female rats was found to induce the parallel appearance to both alpha2u globulin and its corresponding mRNA. Both hypophysectomy and adrenalectomy which are known to reduce the level of alpha2u globulin in the urine of male rats were found also to reduce the hepatic level of alpha2u mRNA. The results indicate that hormonal control of alpha2u globulin synthesis in rat liver is achieved primarily through regulation of its translatable mRNA level and that more than one hormone may participate in this regulation.

Alpha-Globulins↗
PubMed1975

Estrogenic inhibition of the hepatic synthesis of alpha2u globulin in the rat.

The hepatic synthesis of the androgen-dependent urinary protein in the rat, called alpha2u globulin, is strongly inhibited by estrogens. In mature male rats, treatment with estradiol-17beta (0.5 mug/g body weight) completely inhibits alpha2u synthesis within 6-7 days. Following withdrawal of estrogen treatment alpha 2u synthesis is not reinitiated for approximately 20 days. Parabiotic joining of estrogen-suppressed male rats with their normal littermates within this lag period fails to change the preparabiotic pattern of alpha2u synthesis in the respective partners. Besides estradiol-17beta, other estrane derivatives such as estrone, estriol and estradiol-17alpha were also found to inhibit the synthesis of alpha2u globulin. All of the above estrane derivatives which inhibit alpha2u synthesis are also found to inhibit the uptake of 5alpha-dihydrotestosterone by the hepatic cytosol androgen binding protein of the mature male rat. Unlike cycloheximide, a known translational inhibitor, estradiol-17beta does not inhibit alpha 2u synthesis in the perfused rat liver.

Alpha-Globulins↗