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Biomedical subjects

L Jameson

Publications and source records attributed to L Jameson.

11 recordsLinked to original sources
PubMed1988

Fluoride release from glass ionomers used as luting agents.

Four glass-ionomer cements were examined for solubility by measuring the fluoride release from a simulated dental restoration. From this study it may be concluded: 1. Glass-ionomer cements as luting agents for dental prostheses release significant quantities of fluoride. 2. Commercially available cements vary in the amounts of fluoride released. 3. The cements with lower powder-to-liquid ratios demonstrated greater fluoride release. 4. The significant release of fluoride indicated that glass-ionomer cements could be effective in reducing caries.

Cementation↗
PubMed1986

Osteopenia and bone fractures in a man with anorexia nervosa and hypogonadism.

Women with anorexia nervosa have reduced skeletal mass. Both anorexia and osteopenia are less common in men. We describe a 22-year-old man with anorexia nervosa and severe osteopenia involving both cortical and trabecular bone who developed a pelvic fracture and multiple vertebral compression fractures. He was found to have secondary hypogonadotropic hypogonadism that was reversible with weight gain. This case illustrates the need to consider osteopenia as a potential complication of anorexia nervosa in males as well as females.

Adult↗
PubMed1984

The gene encoding the beta-subunit of rat luteinizing hormone. Analysis of gene structure and evolution of nucleotide sequence.

The nucleotide sequence of the gene encoding the beta-subunit of rat luteinizing hormone (LH beta) has been determined from a genomic DNA fragment cloned in lambda phage Charon 4A. Blot hybridization of restriction enzyme digests of rat genomic DNA indicates that the gene is present in a single copy. The transcriptional unit is 0.98 kilobase in size and contains three exons interrupted by two introns of 245 and 225 base pairs (bp). The locations of the exon/intron junctions at amino acid codons -16/-15 and +41/+42 have been conserved between the rat LH beta gene and the related genes, human LH beta and human chorionic gonadotropin beta. Using S1 nuclease mapping and oligonucleotide-primed reverse transcription of ovariectomized rat pituitary mRNA, the start of transcription was determined to be 7 bp upstream from the start of translation. Characteristic promoter elements are present in the 5'-flanking region of the gene, including the Goldberg-Hogness sequence, TATAAA, 31 bp, and the consensus CAAT box sequence, 167 bp upstream from the start of transcription, respectively. Within the proximal 200 bp flanking the 5'-region of the transcriptional unit, there is strong homology between the rat and human LH beta genes, suggesting that these regions include sequences which may be important for regulation of gene expression. Isolation and characterization of the rat LH beta gene further defines the evolution of glycoprotein hormone genes and will facilitate the study of cellular and molecular mechanisms which regulate LH beta gene expression.

Amino Acid Sequence↗
PubMed1981

Modification of microtubule steady-state dynamics by phosphorylation of the microtubule-associated proteins.

Phosphorylation of purified microtubule-associated proteins (MAPs) inhibits the rate and extent of MAP-stimulated microtubule assembly. The extent of microtubule assembly is reduced as a result of a decrease in the fraction of tubulin polymerized, without a significant change in the critical protein concentration. The decreased rate of microtubule assembly using phosphorylated MAPs reflects a reduction in microtubule nucleation resulting in fewer, but 2-fold longer, microtubules at steady state. Analysis of microtubule (MT) dynamics at steady state reveals that the rate of directional incorporation of subunits (flux) is 22 subunits.MT-1.sec-1 with phosphorylated MAPs, compared to 10 subunits.MT-1.sec-1 with unphosphorylated MAPs. The initial rate of disassembly determined by isothermal dilution is 232 subunits.MT-1.sec-1 for microtubules assembled with phosphorylated MAPs, compared to 102 subunits.MT-1.sec-1 for microtubules assembled with unphosphorylated MAPs. By using these results, the directionality (the number of successful subunit additions relative to the total number of association events per unit time) for subunit addition is found to be 0.1 for microtubules assembled with either phosphorylated or unphosphorylated MAPs. These observations are interpreted in terms of a mechanism in which phosphorylation of MAPs increases the rate of steady-state subunit flux by an equivalent enhancement of the rates of subunit association and dissociation, such that the critical protein concentration and directionality remain unchanged.

Animals↗
PubMed1980

Inhibition of microtubule assembly by phosphorylation of microtubule-associated proteins.

32P labeling of microtubular protein by endogenous protein kinase activity is shown to result from a net increase in protein-bound phosphate and is not the result of a phosphate exchange reaction between ATP and phosphoprotein. Protein phosphorylation is maximal in the presence of 0.5 mM Mg2+ and 0.25 mM ATP, resulting in approximately 2.8 nmol of phosphate/mg of protein. However, phosphorylation can be increased two-to threefold by cAMP. The protein substrates for phosphorylation either the absence or presence of cAMP are the microtubule-associated proteins which copurify with tubulin and promote microtubule assembly. Phosphorylation of microtubule-associated proteins inhibits both the rate and extent of microtubule assembly when the protein is exposed to conditions which result in dissociation of rings. These results are taken to indicate that phosphorylation modifies MAPs so that they have a reduced ability to form an assembly-competent complex with tubulin.

Animals↗
PubMedDate not supplied

Development and implementation of novel community outreach methods in women's health issues: the National Centers of Excellence in Women's Health.

Numerous outreach efforts have been employed to educate both lay and professional communities about many medical issues. As part of our contracts with the Public Health Service, Office of Women's Health, Department of Health and Human Services, the National Centers of Excellence (CoEs) in Women's Health have been charged with creating innovative and effective methods of educating these audiences about the major issues involved in women's health. This mission is particularly critical in the arena of women's health, as women are responsible for approximately 75% of the healthcare decisions made by and for American families, and past efforts to provide them with good, evidence-based information have been fraught with difficulties ranging from financial to cultural. We report herein some of our successful novel outreach efforts. A common thread throughout this account is that among the most successful of the outreach activities are those that involve or incorporate existing community groups committed to women's health.

Community Health Centers↗