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Biomedical subjects

S Law

Publications and source records attributed to S Law.

86 records · Page 5Linked to original sources
PubMed1984

Converting-enzyme inhibition and 1-sarcosine-8-isoleucine-angiotensin II: effects on renal function in the dehydrated sheep.

The effect of a converting-enzyme inhibitor (captopril) was studied in nine conscious dehydrated Merino ewes. Captopril (4 mg I.V. over 40 min) caused significant decreases in mean arterial blood pressure (M.A.B.P.), renal vascular resistance (R.V.R.) and filtration fraction, and increases in urine flow (V), sodium excretion, glomerular filtration rate (G.F.R.), renal plasma flow, solute clearance (Cosm), solute-free water reabsorption (TC, H2O) and plasma renin activity (P.R.A.). None of these effects was observed when captopril was similarly administered to sheep pretreated with angiotensin II (AII) receptor blocker, 1-sarcosine-8-isoleucine-AII (sarileucin). It is concluded that the effects of captopril were probably not due to bradykinin potentiation but rather to decreased levels of circulating AII. The effect of sarileucin itself was complex. It effectively blocked the pressor response to administered AII, but it also had an AII-like effect indicated by a rise in R.V.R., and decreases in V, G.F.R., Cosm and TC, H2O. This apparent mixture of AII agonist and antagonist properties probably accounts for the absence of any change in M.A.B.P. or P.R.A. during sarileucin administration.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1983

Human plasma proapoA-I: isolation and amino-terminal sequence.

Human apoA-I is synthesized as preproapoA-I, a 267 amino acid precursor apolipoprotein. PreproapoA-I initially undergoes intracellular co-translational proteolytic cleavage into proapoA-I. ProapoA-I is secreted from the cell and was isolated from thoracic duct lymph in the apoA-I1 isoform position. The amino-terminal sequence of proapoA-I isolated from human lymph revealed the presence of 6 additional amino acids, Arg-His-Phe-Trp-Gln-Gln, on the amino-terminal end of apoA-I consistent with the proapoA-I sequence determined by nucleic acid sequence analysis of cloned apoA-I. Our results indicate that proapoA-I is present in human plasma, and undergoes post-translational proteolytic cleavage to mature plasma apoA-I.

Amino Acid Sequence↗
PubMed1982

The effects of an angiotensin blocker (saralasin) on kidney function in dehydrated sheep.

Saralasin, an angiotensin II analogue and receptor blocker, was infused at 7 and 15 micrograms . min-1 into dehydrated conscious Merino ewes. This caused mean arterial blood pressure, cardiac output, heart rate and renal vascular resistance to fall, and central venous pressure to rise. Renal plasma flow was unaffected but there were significant reductions in glomerular filtration rate, filtration fraction, urine flow, sodium and potassium excretion, solute clearance and solute-free water reabsorption. It is suggested that saralasin produced these effects by inhibiting endogenous angiotensin II activity, and in particular by causing a reduction in renal post-glomerular resistance. This in turn caused a fall in glomerular filtration rate and filtration fraction. While saralasin might have had effects on renal tubular function and perhaps on vasopressin secretion, the observed effects on renal function can be explained by the decrease in glomerular filtration rate and filtration fraction.

Angiotensin II↗
PubMed1981

Simple filter paper method for home monitoring of blood glucose, lactate, and 3-hydroxybutyrate.

Previous methods for assessing the control of diabetes at home have concentrated on the measurement of glucose concentrations in urine and, more recently, blood. These levels reflect only one aspect of deranged metabolism in the disease. A technique is described whereby glucose, lactate, and 3-hydroxybutyrate can be measured in capillary blood samples dried on boric acid impregnated filter paper. The technique is sufficiently sensitive to measure 0.05 mmol/l glucose, 0.02 mmol/l lactate, and 0.004 mmol/1 3-hydroxybutyrate with precisions of 4.0%, 4.5%, and 8.0%, respectively. This method could prove useful in the broader metabolic assessment of the diabetic state.

3-Hydroxybutyric Acid↗
PubMed1980

Molecular cloning of DNA complementary to a mouse alpha-fetoprotein mRNA sequence.

DNA complementary to mouse yolk sac messenger RNA has been inserted at the PstI site of the plasmid pBR322 by annealing of the oligo(dG)-tailed plasmid DNA with the oligo(dC)-tailed mouse DNA. Transformation of Escherichia coli strain RRI with this annealed DNA yielded clones bearing recombinant plasmids. The clones were screened for DNA complementary to mouse alpha-fetoprotein (AFP) messenger RNA sequences by hybridization with a cDNA probe transcribed from an AFP mRNA of over 90% purity. Out of nine plasmids that were isolated and analyzed by restiction mapping, all had homologous insert DNA of various lengths. The plasmid with the longest insert, pAF6, contained 1.65 kb of added DNA, which is about 70% of the AFP mRNA. This clone was positively identified by a hybridization-translation procedure to contain a cDNA sequence for AFP. A restriction map of this clone and the orientation of the message are presented.

Animals↗
PubMedDate not supplied

New studies of the alcohol dehydrogenase cline in D. melanogaster from Mexico.

An altitudinal cline of frequencies of alcohol dehydrogenase alleles occurs in D. melanogaster populations of southeastern Mexico. A similar cline of two aldehyde oxidase alleles is present, but frequencies of esterase-6 alleles are not distributed clinically. Collections were made from small dispersed populations. Some gene flow occurred throughout the lowlands according to the distribution of two moderately endemic autosomal inversions and five previously described inversions. The clines are believed dependent on a limited gene flow between temperature races of D. melanogaster.

Alcohol Oxidoreductases↗
PubMedDate not supplied

Cerebellar cortical degeneration in association with small-cell carcinoma of the oesophagus.

We report the association of paraneoplastic cerebellar cortical degeneration with small-cell oesophageal carcinoma in a 60-year-old woman and describe the histopathological findings. We believe this to be the first report of such an occurrence. The cytoplasmic antigen PGP 9.5, which is strongly expressed in cerebellar Purkinje cells, was identified immunohistologically in the primary tumour and immunoglobulin demonstrated on Purkinje cells. These findings support an immunological pathogenesis for this condition and suggest that it is mediated by antibodies directed against tumour antigen which cross-react with Purkinje cells.

Antibodies, Monoclonal↗
PubMedDate not supplied

Gastric rupture after Heimlich maneuver and cardiopulmonary resuscitation.

Choking is a common emergency problem. The Heimlich maneuver is unquestionably effective in relieving airway obstruction. Serious and life-threatening complications may arise, however, if the maneuver is applied incorrectly. Two cases of gastric rupture after Heimlich maneuver are reported. Lay public, paramedics and the medical professionals should be educated with the correct technique of Heimlich maneuver and its potential complications. All patients receiving Heimlich maneuver should be examined by an experienced physician.

Aged↗
PubMedDate not supplied

Dexamethasone phosphate stability and contamination of solutions stored in syringes.

The stability of 10 mg/mL dexamethasone sodium phosphate injection was evaluated using a validated, stability-indicating liquid chromatographic method during 91 days storage in glass and 55 days storage in plastic syringes with rubber plungers. The presence of accelerators, commonly used in the manufacture of rubber, mercaptobenzothiazole (MBT), tetramethyl thiuram disulfide (TMTD) and tetraethyl thiuram disulfide (TETD), was monitored on day 101 and after 18 months storage. During the 91-day study period there was no significant trend for dexamethasone phosphate concentrations in Glaspak syringes to decrease in solutions stored at room temperature or 4 degrees C. The concentration remaining in each syringe on the final day of analysis was greater than 95% of the initial concentration. In Monject plastic syringes there was no significant decrease in the dexamethasone phosphate concentration over 35 days with 1 mL syringes or 55 days with 3 mL syringes at either room temperature or 4 degrees C. The concentration remaining in each syringe on the final day of analysis was greater than 93% of the initial concentration. Analysis of samples for leachates on day 101 failed to demonstrate any contamination. However, re-analysis of the syringes following 18 months storage indicated contamination by a number of compounds. The results indicate that sorption of dexamethasone phosphate to the syringe barrel or plunger did not occur to a clinically important degree. We conclude that dexamethasone phosphate solutions (10 mg/mL) stored at 4 degrees C or 23 degrees C for up to 91 days in Glaspak syringes or 55 days in plastic Monject syringes will retain more than 93% of the initial dexamethasone concentration. Furthermore after 101 days there was no measurable contamination of the dexamethasone phosphate solution, although after 18 months considerable contamination was observed.

Chromatography, Liquid↗