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J Childs

Publications and source records attributed to J Childs.

26 records · Page 2Linked to original sources
PubMed1988

Production and characterization of human basic fibroblast growth factor from Escherichia coli.

The cDNA sequence coding for human basic fibroblast growth factor (bFGF) has been cloned downstream of a transcription promoter recognized by the bacteriophage T7 RNA polymerase. Initiation of translation at the fgf gene has been coupled to upstream translation of a fragment of the T7 phi 10 gene. Expression of the fgf gene in this system can lead to an accumulation of approximately 40 mg/liter/A600 unit of bFGF. This material can be purified close to homogeneity from a soluble protein extract on a heparin-Sepharose column. bFGF so obtained has been shown to have bioactivity indistinguishable from human placental fibroblast growth factor in mitogenicity, synthesis of plasminogen activator, and angiogenesis assays.

Amino Acid Sequence↗
PubMed1985

Beneficial effects from systematic dosage reduction of the diuretic, chlorthalidone: a randomized study within a clinical trial.

The purpose of this study was to determine the effects on blood pressure and selected biochemical measures of reducing the dosage of chlorthalidone from 100 mg to 50 mg. Within the larger study (Multiple Risk Factor Intervention Trial), 140 Special Intervention hypertensive men, taking 100 mg of chlorthalidone daily, were randomly assigned to either a continuation of 100 mg or a dosage reduction to 50 mg daily. Men were followed monthly for 4 months. Measures were made of blood pressure, serum potassium, serum uric acid, serum glucose, serum cholesterol, and triglycerides. Blood pressure change from baseline to 4 months revealed a significantly higher diastolic blood pressure in the group continued on the 100 mg dose compared to the dose reduction group. However, analysis of covariance, which took into account baseline differences in blood pressure, resulted in a nonsignificant difference in follow-up blood pressure (systolic and diastolic) between groups. Serum potassium increased significantly in the dose reduction group, especially in those participants taking supplemental potassium chloride. The results of this study demonstrate that a reduced dose of 50 mg chlorthalidone over the 4-month period was as effective as the 100 mg dose in long-term, well-controlled hypertensive men. Careful study of other antihypertensive agents is warranted to determine the drug dose that is maximally effective for blood pressure lowering and that also minimized toxic and adverse effects.

Blood Glucose↗
PubMed1985

Cholinergic stimulation of chromaffin cells induces rapid coating of the plasma membrane.

Stimulation of primary bovine adrenal chromaffin cells by carbachol produced a 6-fold increase in cell surface coated pits within 30 s. This coat appeared not to be recruited from a preformed pool at the plasma membrane, but from some pool transparent to electron microscopy. The number of coated pits appeared to decrease rapidly after 1 to 2 min stimulation, but processing for electron microscopy using tannic acid to enhance contrast indicated that both coated pits and closed coated vesicles were increased relative to unstimulated cells for up to 30 min. Analyses of purified adrenal medulla coated vesicles showed a lipid composition close to that expected for cell surface membrane, but there were only trace levels of plasma membrane marker enzymes. Coated vesicles contained significant amounts of both membrane and content proteins characteristic of the chromaffin granule, suggesting that medulla coated vesicles preferentially carry secretion granule proteins. The kinetics of stimulus-dependent formation of coated membrane in the cortical zone of chromaffin cells is closely similar to that observed for secretion granule membrane retrieval.

Adrenal Medulla↗
PubMed1984

Cellular distribution of three mammalian Ca2+-binding proteins related to Torpedo calelectrin.

Addition of Ca2+ to post-microsomal fractions of bovine adrenal or liver produced a sedimentable complex of membrane vesicles and cytoplasmic proteins. Proteins with apparent mol. wts. 70 000, 36 000 and 32 500 were solubilized from this complex by Ca2+ chelation. The 36 000 mol. wt. protein (p36) was immunoprecipitated by an antiserum specific for pp36, a major substrate for Rous sarcoma virus src-gene tyrosine kinase. This protein was present in many mesenchymal cells and associated with membrane cytoskeleton of bovine fibroblasts in a Ca2+-dependent manner. The 70 000 and 32 500 mol. wt. proteins were widely distributed in established cell lines, but were not clearly associated with cell organelles in tissue sections, nor retained in cytoskeleton preparations. On immunoblots p36 reacted strongly with antibodies produced against the electric fish protein Torpedo calelectrin and the similar Ca2+-binding properties and subunit mol. wts. of these proteins suggests that they might be functionally related. Since Torpedo calelectrin, p70, p36 and p32.5 were bound by lipid vesicles or microsomal membranes at micromolar free Ca2+ concentrations, regulated association with intrinsic membrane components may be involved in the functions of these widespread proteins.

Adrenal Medulla↗
PubMed1982

Task monotony and performance efficacy of mentally retarded young adults.

Mildly mentally retarded young adults were exposed to one of three training arrangements for vigilance performance, a monitoring task that some professionals consider uniquely appropriate for such persons because they are assumed to be less susceptible to boredom. Evidence indicated that accuracy generally declines over time. Training approaches used in this study allowed component analysis of procedures used in a previous study in which accuracy did not decline. Replication of the divergent study's procedures and alternate arrangements produced the characteristic vigilance decrement that was unrelated to on-task errors but varied with certain off-task behavior. Accuracy levels mirrored the degree of tangible reinforcement but, like nonretarded observers, retarded monitors found the task boring or otherwise unrewarding.

Adult↗
PubMedDate not supplied

Emerging zoonoses.

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Animals↗