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Biomedical subjects

S J Kelly

Publications and source records attributed to S J Kelly.

At least 73 records · Page 4Linked to original sources
PubMed1983

Effect of transfer RNA from various sources on placental messenger RNA translation.

Poly(A+)-containing mRNA from human term placenta was used to direct protein synthesis in a nuclease-treated rabbit reticulocyte lysate, which is dependent on mRNA and tRNA for maximal activity. The major protein product was human pre-placental lactogen (hPL). Addition of tRNA from rabbit liver, rabbit reticulocyte, human first trimester and term placenta, human liver and yeast resulted in 2-5-fold stimulation of [35S]methionine incorporation into total protein. Although all mammalian tRNA increased hPL synthesis, the relative synthesis as compared to endogenous globin was markedly different and most efficient with tRNA from term placenta. Addition of yeast tRNA increased total incorporation 3-fold but decreased incorporation of [35S]methionine into pre-hPL. These results suggest that the population of isoacceptor tRNAs may influence the expression of hPL in term placenta. Results are discussed by showing codon bias and usage of mRNA coding for hPL, alpha- and beta-hCG, rabbit globin and yeast alcohol dehydrogenase I.

Female↗
PubMed1982

Steady state urinary excretion of theophylline and its metabolites in the presence of erythromycin.

The effect of erythromycin on the quantitative pattern of urinary excretion of theophylline and its known metabolites at steady state in eight human subjects was examined. The percent of dose excreted of the various compounds in the absence and presence of the antibiotic were as follows: theophylline, 9.3% vs. 16.3%; 1, 3-dimethyluric acid, 51.9% vs. 59.6%; 3-methylxanthine, 11.9% vs. 13.0%; and 1-methyluric acid, 27.3% vs. 31.6%. These results show that erythromycin did not influence the metabolism of theophylline under the experimental protocol employed.

Adult↗
PubMed1979

Investigations into the degree of cell mixing that occurs between the 8-cell stage and the blastocyst stage of mouse development.

This study was designed to assess the degree of cell mixing that occurs during the early development of the mouse embryo, and thus provide information which is important in relation to the current theories of differentiation. Previous studies of this nature have involved either chimeric composites, or have only followed a very limited number of cells in the embryo. Here the products of one of the 4-cell stage blastomeres have been labeled with tritiated thymidine, at a level which allows their descendants to be identified three or four cell divisions later, and recombined with the remaining blastomeres of the same embryo. After fixing and sectioning of the embryos at the blastocyst stage the locations of the labelled cells have been analyzed to assess the degree of clumping that they display. A significant tendency for the products of this one 4-cell stage blastomere to be confined to a single area in the blastocyst is demonstrated. This indicates that there is little marked cell movement during the observation period. The relevance of these results to current knowledge of blastocyst development is discussed.

Animals↗
PubMed1978

Cell division and cell allocation in early mouse development.

Cell division was observed in intact and dissociated mouse embryos between the 2-cell stage and the blastocyst in embryos developing in culture. Division to the 4-cell stage was usually asynchronous. The first cell to divide to the 4-cell stage produced descendants which tended to divide ahead of those cells produced by its slow partner at all subsequent stages of development up to the blastocyte stage. The descendants of the first cell to divide to the 4-cell stage did not subsequently have short cell cycles. The first cell or last cell to divide from the 4-cell stage was labelled with tritiated thymidine. The embryo was reassembled, and it was found that the first pair of cells to reach the 8-cell stage contributed disproportionately more descendants to the ICM when compared with the last cell to divide to the 8-cell stage.

Animals↗
PubMed1977

Enzymic hydrolysis of phosphonate esters. Reaction mechanism of intestinal 5'-nucleotide phosphodiesterase.

The mechanism of bovine intestinal 5'-nucleotide phosphodiesterase was investigated by determining kinetic constants of systematically varied substrates, with emphasis on esters of phosphonic acids (which have much higer Vmax values than conventional phosphodiester substrates), and by pre-steady-state kinetics using bis(4-nitrophenyl) phosphate as substrate. The results suggest a ping-pong type mechanism, with participation of a covalent enzyme intermediate.

Animals↗
PubMed1976

The effect of short-term labelling in (3H) thymidine on the viability of mouse blastomeres: alone and in combination with unlabelled blastomeres.

A method of labelling 8-cell-stage mouse blastomeres with [3H]thymidine is described, which allows them to be followed to the late blastocyst stage and is compatible with normal postimplantation development. However, the [3H]thymidine does affect the postimplantation vigour of the cells when placed in competition with unlabelled cells in blastomere aggregates. This suggests that caution should be used in interpreting results using [3H]thymidine as a label for early mammalian cells.

Animals↗
PubMed1975

Hydrolysis of phosphonate esters catalyzed by 5'-nucleotide phosphodiesterase.

4-Nitrophenyl and 2-napthyl monoesters of phenylphosphonic acid have been synthesized, and an enzyme catalyzing their hydrolysis was resolved from alkaline phosphatase of a commerical calf intestinal alkaline phosphatase preparation by extensive ion-exchange chromatography, chromatography on L-phenylalanyl-Sepharose with a decreasing gradient of (NH4) 2SO4, and gel filtration. Detergent-solubilized enzyme from fresh bovine intestine was purified after (NH4)2SO4 fractionation by the same technique. The purified enzyme is homogeneous by polyacrylamide gel electrophoresis and sedimentation equilibrium centrifugation. It has a molecular weight of 108,000, contains approximately 21% carbohydrate, and has an amino acid composition considerably different from that reported from alkaline phosphatase from the same tissue. The homogeneous intestinal enzyme, an efficient catalyst of phosphonate ester hydoolysis but not of phosphate monoester hydrolysis, was identified as a 5'-nucleotide phosphodiesterase by its ability to hydrolyze 4-nitrophenyl esters of 5'-TMP but not of 3'-TMP. Also consistent with this identification was the ability of the enzyme to hydrolyze 5'-ATP to 5'-AMP and PPi, NAD+ to 5'-AMP and NMN, TpT to 5'-TMP and thymidine, pApApApA to 5'-AMP, and only the single-stranded portion of tRNA from the 3'-OH end. Snake venom 5'-nucleotide phosphodiesterase also hydrolyzes phosphonate esters, but 3'-nucleotide phosphodiesterase of spleen and cyclic 3',5'-AMP phosphodiesterase do not. Thus, types of phosphodiesterases can be conveniently distinguished by their ability to hydrolyze phosphonate esters. As substrates for 5'-nucleotide phosphodiesterases, phosphonate esters are preferable to the more conventional esters of nucleotides and bis(4-nitrophenyl) phosphate because of their superior stability and ease of synthesis. Furthermore, the rate of hydrolysis of phosphonate esters under saturating conditions is greater than that of the conventional substrates. At substrate concentrations of 1 mM the rates of hydrolysis of phosphonate esters and of nucleotide esters are comparable and both superior to that of bis(4-nitrophenyl) phosphate.

Amino Acids↗
PubMed1973

Detection of coronavirus strain 692 by immune electron microscopy.

Utilization of the technique of immune electron microscopy has enabled the detection of a coronavirus in organ culture harvests derived from a washing from an adult with an acute upper respiratory tract illness; convalescent serum was the source of specific antibody.

Journal Article↗
PubMedDate not supplied

Changes in brain microvasculature resulting from early postnatal alcohol exposure.

The microvasculature in selected brain regions in rats was examined on postnatal day 10 following exposure to alcohol on postnatal days 4 to 10. The alcohol-exposed rats were artificially reared and given 6.6 g/kg of ethanol condensed into 8 hr of each 24-hr period. A gastrostomy-control group was reared in the same manner but maltose-dextrin was substituted for ethanol in the formula. A suckle-control group was reared normally by dams. Measurements were taken from midsagittal sections of the cerebellum and sections of the hippocampal formation at a midtemporal level. Although the overall area of the vermal cerebellum was decreased as a consequence of the alcohol exposure, the capillary density was unchanged. However, cerebellar capillary diameters were increased in some lobules in the alcohol-exposed rats. In the dentate gyrus, there was a trend toward a decrease in capillary numerical density but no change in regional area or capillary diameter in the alcohol-exposed rats. In the hippocampus proper, there was a decrease in regional area, no change in capillary density, and an increase in capillary diameter due to alcohol. These results indicate that alcohol exposure during the early postnatal period affects the microvasculature differentially in the cerebellum, hippocampus proper and dentate gyrus.

Animals↗
PubMedDate not supplied

Alterations in sensorimotor development: relationship to postnatal alcohol exposure.

The sensory, motor, and physical development of rats reared by dams, artificially reared on milk formula alone, or on milk formula combined with alcohol was examined. The rats given alcohol received 6.6 g/kg/day, which was administered either as 12 fractions distributed uniformly over 24 hours and resulted in stable blood alcohol concentrations (BACs) of 85 mg/dl, or condensed into 4 fractions over 8 hours and resulted in maximum and minimum BACs of 411 mg/dl and 45 mg/dl, respectively. Pups were reared artificially from postnatal days 4 to 12 with alcohol exposure occurring on days 4 to 10. A sensorimotor test battery was then administered from postnatal day 12 to postnatal day 30. The condensed alcohol exposure resulted in age-dependent hyperactivity, a delay in tooth eruption, disruption of balance and of the ability to use the hindlimbs in a coordinated fashion, and a delay in the acquisition of the midair righting reflex. The midair righting reflex also was disrupted by uniform alcohol exposure. Thus, postnatal alcohol exposure that produces high BACs causes more severe developmental aberrations than the same daily dose administered in a pattern producing low BACs.

Animals↗
PubMedDate not supplied

Sexually dimorphic effects of perinatal alcohol exposure on social interactions and amygdala DNA and DOPAC concentrations.

The hypotheses that exposure of rats to alcohol during a period roughly equivalent to the human third trimester induces changes in social interactions and neurotransmitter and DNA concentrations in the amygdala region were examined. The alcohol exposure was accomplished via an artificial rearing procedure. There were two alcohol-exposed groups (3 and 5 g/kg/day of ethanol) and two control groups (one artificially reared but not exposed to alcohol and one reared normally by dams) in all studies. Active social interactions were reduced in the male 5 g/kg/day group and increased in both female alcohol-exposed groups compared to their respective control groups. Exposure to 5 g/kg/day of alcohol reduced the DNA concentration in the amygdala region of male rats compared to either control group; there were no effects in females. Because some systems have been shown to exhibit alcohol-induced changes only under stressed conditions, noradrenaline, dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin, and 5-hydroxyindoleacetic acid (5-HIAA) concentrations were measured in the amygdala region under both nonstressed and stressed conditions. The stress-induced increase in DOPAC concentrations was enhanced in the female high dose group compared to either control group; there were no effects in males. In summary, alcohol exposure during the early postnatal period altered social interactions and DOPAC and DNA concentrations in the amygdala region in a sexually dimorphic manner.

3,4-Dihydroxyphenylacetic Acid↗