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Biomedical subjects

D Rogers

Publications and source records attributed to D Rogers.

At least 127 records · Page 7Linked to original sources
PubMed1981

Gonadotropin releasing hormone stimulates calmodulin redistribution in rat pituitary.

Calcium (Ca2+) seems to have an informational role in many tissues. In particular, it fulfills the requirements of a second messenger for gonadotropin releasing hormone (GnRH)-stimulated luteinizing hormone (LH) release from the pituitary gonadotrope (see ref. 1 for review). Very little is known about the effect of this ion on intracellular targets or the mechanism by which Ca2+ mobilization stimulates LH release. One intracellular target for Ca2+ is calmodulin, a ubiquitous intracellular Ca2+ receptor that has been shown to modulate many cellular functions, including cyclic nucleotide and glycogen metabolism, protein phosphorylation, microtubule assembly and disassembly, a Ca2+ flux, and the activities of NAD kinase, tryptophan 5' monooxidase and phospholipase A2 (see refs 2-5 for reviews). We have now used a specific and sensitive radioimmunoassay to determine the quantity and distribution of calmodulin in the gonadotrope before and during GnRH-stimulated LH release. The data indicate that GnRH stimulates redistribution of calmodulin from the cytosol to the plasma membrane and suggest that the molecule may have a role in the mechanism of stimulus-secretion coupling.

Animals↗
PubMed1981

The radiographic appearance of the stomach in Cronkhite-Canada syndrome.

Cronkhite-Canada syndrome is a nonfamilial form of diffuse gastrointestinal polyposis associated with ectodermal abnormalities of alopecia, and hyperpigmentation. Recent experience with two patients in whom the diagnosis was pathologically confirmed suggest that there is a specific radiographic appearance to the stomach in this disorder. There are enlarged rugal folds, polyps, and "whiskering" (appearance of multiple tiny projections due to barium trapped between nodular excrescences of rugae). When accompanied by the characteristic ectodermal abnormalities, this radiographic pattern aids in the diagnosis of this complex clinical entity.

Cyclophosphamide↗
PubMed1980

The disposition of indomethacin in preterm babies.

Limited pharmacokinetic data are available concerning the disposition of indomethacin in preterm infants. Since oral absorption of the drug may be poor or incomplete, the current report provides pharmacokinetic data on 37 premature infants who received indomethacin intravenously. Each of these infants had a hemodynamically significant patent ductus arteriosus. Findings included variable serum indomethacin concentrations from four to 12 hours after a single dose of 0.2 mg/kg. Female preterm infants generally had lower serum drug values at 12 hours and beyond when compared to males. An extrauterine age dependence was found of serum indomethacin levels. Total body clearance, serum half lives and volumes of distribution also bore a direct relationship to extrauterine age. Thus, when indomethacin is administered shortly after birth, one may anticipate a longer duration of action after a single dose and a relatively greater risk of accumulation of the drug when more than one dose is required for treating a duct al patency.

Age Factors↗
PubMed1978

Fidelity of conjugation in Saccharomyces cerevisiae.

An efficient method for the production of synchronous zygotes in Saccharomyces cerevisiae is described. Cells were synchronised under defined conditions in either an a, alpha mixed culture or by incubation of each mating type in cell-free medium in which cells of the opposite mating type had been grown. Synchronised cells were allowed to fuse under defined conditions on filter membranes. This method was used to test the fidelity of conjugation in S. cerevisiae. Under conditions where cells of a or alpha mating type were in contact with up to 6 cells of each of two strains of opposite mating type, less than 1 multiple mating in 10(4) diploid matings occurred. It is concluded that is sexual conjugation in S. cerevisiae some process distinct from cell contact restricts cell fusion to paired combinations of conjugant cells.

Cell Communication↗
PubMed1976

Measurement of acute and chronic behavioural effects of methamphetamine in the mouse.

A simple and reliable method was developed for rating the dose-related behavioural effects of methamphetamine in male Swiss Albino mice for acute or chronic drug treatment. This procedure was based on a frequency count of certain behaviours made at 15-min intervals over a 90-min period following drug administration. The Fisher Randomization procedure was adapted to analyze behavioural data for the chronic studies. Clear-cut, dose-related behavioural responses occurred following acute (+)-methamphetamine administration and ranged from decreased quiescence (0.64 mg/kg) through increased locomotor activity (2.5 mg/kg), a mixture of stereotyped behaviour and increased locomotor activity (5.0 and 7.5 mg/kg), to primarily stereotyped gnawing, licking or sniffing (10 mg/kg). In studies involving chronic administration of (+)-methamphetamine at 0.64, 2.5 and 10 mg/kg conducted over six and seven weeks, behavioural responses were more exaggerated than in acute studies. All behaviours returned to normal levels in the recovery week except for locomotor activity at the 10 mg/kg dosage. In some animals, chronic treatment with 10 mg/kg (+)-methamphetamine led to protracted self-tearing that replaced the gnawing, licking, sniffing stereotype.

Animals↗
PubMed1976

Papers and originals.

Six cases of persistent non-accidental poisoning of children by their parents are reported. Certain features may draw attention to the diagnosis, particularly bizarre symptoms and signs with no apparent pathological explanation, and toxicological analysis should be carried out to obtain rapid confirmation of the diagnosis. The underlying disorder may include marital conflict, overinvolvement between parent and child, or drug abuse in the parents. A suggested plan of action for managing this problem is outlined.

Child↗
PubMed1968

Osmotic pools in Escherichia coli.

Osmotically sensitive pools in Escherichia coli are released by treatment with warm water without loss in viability or of cytoplasmic components. The rates of protein release are linear and are inversely dependent on the osmolarity of the medium, and only discrete amounts are released. These pools, which are thought to be periplasmic and mesosomal, are stabilized with magnesium ions; material released in the presence of these ions may have been localized outside of these pools at the cell surface.

Acid Phosphatase↗