Biomedical subjects

R B Young

Publications and source records attributed to R B Young.

At least 19 recordsLinked to original sources

PubMed1990

Protein metabolism in chicken muscle cell cultures treated with cimaterol.

Primary muscle cell cultures were prepared from the leg muscle of 12-d broiler chicken embryos. The partitioning agent cimaterol (10(-6) to 10(-10) M) was added on d 1 and each day thereafter, and cells were studied after 7 d in culture. Cimaterol had no effect at any level either on the percentage of nuclei within multinucleated myotubes or on the total number of nuclei within myotubes. At 10(-7) M cimaterol, the quantity of the myofibrillar protein fraction was increased by 25.1 +/- 8.0% (P less than .05) and the quantity of myosin heavy chain was increased by 30.9 +/- 4.5% (P less than .05). To understand the basis for the increase in myofibrillar protein, the incorporation rate of [3H]Leu was measured in pulse labeling experiments. The apparent synthesis rate of the soluble protein fraction and the crude myofibrillar fraction was not significantly increased by cimaterol; however, cimaterol levels greater than 10(-8) M caused a 10 to 12% increase (P less than .05) in the incorporation rate of [3H]Leu into myosin heavy chain. The effect of cimaterol on release of [3H]Leu from prelabeled protein also was assessed in pulse-chase experiments; the apparent rate of protein degradation was inhibited by 10 to 15% (P less than .05) at the higher levels of cimaterol. Dot blot analysis indicated that the quantity of myosin heavy chain mRNA was elevated in cimaterol-treated cultures. Thus, the increased quantity of myofibrillar proteins in embryonic broiler muscle cell cultures is the combined result of a stimulation in the rate of protein synthesis and an inhibition in the rate of protein degradation.

Adrenergic beta-Agonists↗

PubMed1987

Effect of insulin on phosphorus metabolism in red blood cells from patients with schizophrenia and psychotic depressions.

In an exploratory study of the metabolism of selected intermediates of glycolysis in rbc of patients with schizophrenia and with major depressive disorders, statistically significant decreases in the RSA of 2,3-DPG were found in the rbc of patients with psychotic disorders compared to normal subjects. No statistically significant differences were observed in the RSA of any of the other glycolytic intermediates studied comparing patients to normal subjects.

Adult↗

PubMed1987

Genomic clones encoding chicken myosin heavy-chain genes.

A chicken genomic library was screened with a cDNA probe containing the 3' coding and noncoding portions of quail fast-twitch skeletal muscle myosin heavy chain (MHC). This probe hybridized to seven to nine bands on Southern blots of chicken genomic DNA, and 17 clones that hybridized to this probe were obtained from the genomic library. Partial restriction maps were constructed and probable orientation of transcription was determined for each of the 17 clones. These maps indicate the presence of at least 14 unique MHC genes or pseudogenes. Dot-blot hybridization analysis using DNA complementary to RNA from a variety of chicken tissues demonstrated that these genes are all related to the gene for sarcomeric MHC, and permitted tentative assignment of the tissue of expression for several of the MHC isoforms. To substantiate further the dot-blot data, a subclone of one of the genes (4b1), which showed significant homology with adult breast muscle RNA but which also showed weaker hybridization to RNA from other tissues, was sequenced. The sequence data verified that the clone contains a portion of a MHC gene, that it contains both 3' coding and noncoding regions, and that its predicted amino acid sequence is identical (with 96% nucleotide homology) to that of the 75-bp quail fast MHC cDNA clone published by Hastings and Emerson (1982). Thus, clone 4b1 contains a portion of one of the genes that is expressed in adult chicken breast skeletal muscle tissue.

Amino Acid Sequence↗

PubMed1987

Screening of a bovine genomic library for myosin heavy-chain genes.

Restriction enzyme digests of bovine genomic DNA were hybridized against a .37-kilobase (kb) quail embryonic myosin heavy-chain (MHC) copy deoxyribonucleic acid (cDNA) probe; containing both translated and nontranslated regions surrounding the 3' end of the gene. These experiments revealed seven to eight different bands of hybridization, indicative of multiple genes of MHC in the bovine genome. Additionally, a bovine genomic recombinant DNA library was screened with the .37-kb probe. Of the 10(6) phage screened, 11 clones containing portions of the MHC genome were identified, and four were selected for further analyses. Characterization of these four clones was carried out by constructing partial restriction enzyme maps of the inserts using six restriction enzymes singly or in combination. Orientation of the inserts with respect to the arms of the vector and with respect to direction of transcription was determined by hybridizing the DNA fragments against either the .37-kb Pst 1 fragment of pcC128 or to the .23-kb Pst I fragment of pcC128. The .23-kb fragment is located upstream from the .37-kg fragment and contains only coding sequence. Therefore, the differential hybridization pattern of these two probes provided a means for determining the probable direction of transcription. These data provide evidence for a myosin multigene family in cattle, as well as illustrating that the organization of these genes around the 3' end is unique for each of the genes analyzed.

Animals↗

PubMed1986

Premature adrenarche. Clinical and diagnostic features.

Premature adrenarche (PA) or isolated growth of sexual hair in young children, is a benign condition that may initially be confused with true precocious puberty or pathologic virilizing disorders. The clinical findings, family history, and serum concentrations of dehydroepiandrosterone sulfate (DHEA-S) were compared in 24 children with PA (79% black females) seen in a 2-year period and in an age-matched control group of 17 black females. Twenty three of 24 patients, but none of the controls, had an adult-type axillary odor. There was a positive family history of PA in only three of 24 children with PA, and in one of 17 controls. The mean serum DHEA-S was significantly higher in the PA children than in the controls, but there was a broad range of concentrations (10-143 micrograms/dl), with values in 10 of 24 cases falling within the control range for age. We conclude that: (1) PA is a relatively common finding in black females between ages 3 and 8, (2) an axillary odor is almost always present in children with PA, and (3) determination of serum DHEA-S may be of some help in confirming the clinical impression of a modest increase in adrenal androgen secretion and in ruling out a more serious disorder. In most cases, however, the diagnosis of PA can be made on the basis of the history, physical examination, and lack of rapid progression over time; the use of laboratory tests to rule out a pathologic virilizing process may best be reserved for those children with very early onset, increased linear growth, or other signs of virilization.

Adrenal Glands↗

PubMed1986

Structural analysis of myosin genes using recombinant DNA techniques.

Myosin, the major protein of the myofibril, consists of two heavy chains with a molecular weight (MW) of 200,000, complexed with four light chains of MW 17,000 to 21,000. Both the heavy and light chains exhibit polymorphisms that are tissue-specific and developmental stage-specific. Myosin heavy chains and light chains appear to be represented in the genome as multigene families in various species, including chickens, cattle, humans, rats, rabbits and nematodes. Myosin heavy-chain proteins have a high amino acid sequence homology among isoforms, and the genes for each isoform likewise exhibit a high degree of nucleotide sequence conservation. The myosin heavy-chain genes have a complex structure and contain up to 65% intervening sequence composed of up to 20 or more individual introns. Partial sequence data, transcriptional orientation and tissue of expression have been determined for several myosin heavy-chain genes. The use of recombinant DNA and associated techniques will eventually yield definitive information on the control of expression of each individual gene, as well as factors that regulate expression of closely related isoforms.

Animals↗

PubMed1985

Calcium and phosphate metabolism in children with idiopathic hypoparathyroidism or pseudohypoparathyroidism: effects of 1,25-dihydroxyvitamin D3.

Two children with congenital hypoparathyroidism and two children with pseudohypoparathyroidism were given maintenance doses of 15 to 45 ng/kg/day 1,25-dihydroxyvitamin D3 for a total of 255 months. The urinary calcium excretion showed an upward elevation after the first 2 years of treatment but was not significantly higher than that in 10 normal control subjects. The renal threshold for phosphate excretion stayed within the normal ranges compared with control values. Two hypercalcemic and two hypocalcemic episodes occurred during this period of treatment. Hypercalcemia was reversed within 1 week after withdrawal of 1,25-dihydroxyvitamin D3. Hypocalcemia was countered by increasing the dose of 1,25-dihydroxyvitamin D3. Renal functions were not adversely affected, as estimated by creatinine clearance and reciprocals of serum creatinine concentrations. The mean serum calcium concentration during 1,25-dihydroxyvitamin D3 treatment was significantly higher (P = 0.001) compared with that obtained during vitamin D2 treatment at a dose of 500 to 3000 IU/kg/day. These data provide additional support for the long-term use of 1,25-dihydroxyvitamin D3 in idiopathic hypoparathyroidism and pseudohypoparathyroidism.

Calcitriol↗

PubMed1979

Myosin synthesis in embryonic chicken fibroblasts.

The rate of constitutive myosin synthesis was measured in cultures of replicating embryonic chicken skin fibroblasts by pulse labeling with [3H]leucine. These cells synthesized the 200,000-dalton heavy chain of myosin (MHC) at a rate of 3.2 x 10(3) molecules/cell/min. Additionally, an independent estimate of the MHC synthesis rate needed to maintain a constant level of constitutive MHC/cell was calculated from total protein content, percentage MHC, fibroblast doubling time, and MHC half-life. This calculated rate of approximately 2.9 x 10(3) molecules/cell/min was in close agreement with the measured rate. By comparison, the synthesis rate of myofibrillar MHC in fully activated muscle cell cultures was approximately 2.9 x 10(4) molecules/nucleus/min.

Animals↗

PubMed1979