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Biomedical subjects

S Moore

Publications and source records attributed to S Moore.

At least 325 records · Page 18Linked to original sources

Spironolactone-induced hyperchloremic acidosis in cirrhosis.

Six patients with alcoholic cirrhosis developed a reversible metabolic acidosis during treatment with the aldosterone antagonist spironolactone. Mean serum bicarbonate concentration decreased significantly with spironolactone therapy (100 to 200 mg/day) from 18.2 +/- 4.5 to 10.9 +/- 3.2 meq/litre (P less than 0.001). Upon withdrawal of spironolactone, serum bicarbonate concentration increased from 10.9 +/- 3.2 to 18.1 +/- 3.5 meq/litre (P less than 0.001). During the development of this hyperchloremic metabolic acidosis, serum potassium concentration rose from 3.7 +/- 0.5 to 5.0 +/- 0.8 meq/litre (P less than 0.005); this reversed after cessation of spironolactone therapy. These effects of spironolactone treatment were not associated with significant alterations in serum creatinine or sodium concentration. Thus, even though an aldosterone antagonist in the treatment of sodium and water retention in cirrhotic patients may prevent hypokalemia and rapid diuresis, it may also induce or worsen another complication: hyperchloremic metabolic acidosis.

Acidosis↗

Platelet interaction with damaged rabbit aorta.

We have quantified the accumulation of 51Cr-labeled washed rabbit platelets on the subendothelium of rabbit aortae following injury with a balloon catheter. The amount of radioactivity that became associated with the damaged wall within 10 minutes of the injury did not change appreciably during the following 24 hours, indicating that there was little turnover of platelets on the injured vessel wall. In addition, by injecting 51Cr-labeled platelets into rabbits at different times after injury, it was possible to estimate the reactivity of the exposed surface to newly injected platelets. Scanning electron microscopy showed that a monolayer of platelets initially formed on the injured surface; the number of platelets associated with the surface decreased over the 7-day observation period. The amount of 51Cr associated with the injured vessel wall also diminished during this period. The ability of the damaged surface to attract fresh platelets gradually decreased during the 7 days following injury. Platelet survival in rabbits was not significantly reduced following the removal of the aortic endothelium (balloon catheter injury 66.3 +/- 12.2 hours, sham operated 72.1 +/- 7.2 hours, untreated controls 76.2 +/- 3.8 hours). Thus, in rabbits, it cannot be assumed that platelet survival provides an estimate of endothelial injury in all circumstances.

Animals↗

Preparation of protease-free and ribonuclease-free pancreatic deoxyribonuclease.

When pancreatic DNase I is used as a specific biochemical reagent in the preparation of nuclear ribonucleic acids or nuclear proteins, freedom from contaminating ribonucleases or proteases is an important property of the enzyme preparation. A simple one-step procedure has been developed to effect complete removal of trypsin, chymotrypsin, and chymotrypsinogen by a combination of affinity chromatography and salting-out adsorption on lima bean protease inhibitor coupled to Sepharose (a column (0.9 X 60 cm) operated in series with a regeneratable 1-ml bed). Commercial preparations of DNase (about 10 mg) give a quantitative yield of the enzyme that is protease-free as evidenced by full stability for more than 10 days at pH 8 and 37 degrees C even in the absence of the protecting action of Ca2+. Removal of the last traces of RNase has been accomplished by affinity chromatography on a column (0.4 X 72 cm) of 5'-(4-aminophenyl-phosphoryl)-uridine 2'(3')-phosphate-Sepharose; the product is a highly active DNase that gives no detectable hydrolysis of RNA by assay on radioactive substrates.

Chromatography, Affinity↗

Urinary tract obstruction and renal failure due to uterine prolapse.

Three women are described in whom obstructive uropathy was found secondary to uterine prolapse. Two of these patients had severe renal failure. It is important to exclude this condition in any woman presenting with renal functional impairment. Potentially damaging urinary tract obstruction should be considered in every patient with a uterine prolapse.

Female↗

Vessel injury and atherosclerosis.

Repeated endothelial injury causes lipid-rich lesion in animals on a normal diet. In severely thrombocytopenic animals these lesions do not form or are markedly inhibited. The occurrence of lipid in some experimental designs is related to continued or repeated deposition of thrombus. Lipid deposition occurs in areas where endothelium is repeatedly removed and regrows. Repeated deposition of thrombus may bring about changes in the metabolism of the neo-intima which favor lipid deposition.

Animals↗

Replacement of the disulfide bond in oxytocin by an amide group. Synthesis and some biological properties of (cyclo-(1-L-aspartic acid,6-L-alpha,beta-diaminopropionic acid))oxytocin.

As part of a continuing investigation of the steric and electronic functions of the disulfide group in neurohypophyseal hormones on their biological activity, the synthesis of "oxytocin lactam", [cyclo-(1-aspartic acid,6-alpha,beta-diaminopropionic acid)]oxytocin, has been undertaken. The protected nonapeptide was prepared in a stepwise manner by solution techniques; after removal of side-chain protecting groups, formation of the briding amide bonds was accomplished by oxidation-reduction condensation. The analogue possesses rat uterotonic, avian vasodepressor, and rat antidiuretic potencies of 16 +/- 2, 6.6 +/- 0.6, and 5.6 +/- 3.8 units/mg, respectively.

Animals↗

A phase-specific adaptation effect of the square-wave grating.

The existence of wide-band, phase-specific channels in the human visual system has been suggested in recent investigations. We used a number of adapting gratings to test for phase-specific adaptation effects. Observers were asked to discriminate between a simple 3 cpd sine-wave grating, (3), and a complex grating composed of this (3) plus a 9 cpd grating combined in one of two phases: peaks-subtract, (3,9:0), or peaks-add, (3,9:pi). The results show a significant phase-specific adaptation effect. That is, following adaptation to a square-wave grating, discrimination performance for (3,9:0) vs. (3) deteriorated significantly more than for (3,9:pi) vs. (3). Adaptation to the first two harmonics of the square-wave, (3,9:0), or a 3 cpd triangle-wave grating failed to produce phase-specific adaptation effects that reached significance.

Adaptation, Ocular↗

Organochlorine insecticide residues in bovine milk and manufactured milk products in Illinois, 1971-76.

Monitoring activities were initiated in 1971 to survey the occurence and levels of organochlorine insecticide residues in bovine milk and manufactured milk products in Illinois. Dieldrin residues were the most prevalent, and were found in 96 percent of the samples. Dieldrin also accounted for the highest average residue concentration (0.09 ppm). Only 0.3% of the samples contained illegal insecticide residues. Levels of DDT and lindane were generally declining, but those for dieldrin and heptachlor epoxide tended to remain constant.

Acetonitriles↗

Ribonuclease inhibitor from human placenta. Purification and properties.

A soluble ribonuclease inhibitor from the human placenta has been purified 4000-fold by a combination of ion exchange and affinity chromatography. The inhibitor has been isolated in 45% yield (about 2 mg/placenta) as a protein that is homogeneous by sodium dodecyl sulfate-gel electrophoresis. In common with the inhibitors of pancreatic ribonuclease from other tissues that have been studied earlier, the placental inhibitor is an acidic protein of molecular weight near 50,000; it forms a 1:1 complex with bovine pancreatic RNase A and is a noncompetitive inhibitor of the pancreatic enzyme, with a Ki of 3 X 10(-10) M. The amino acid composition of the protein has been determined. The protein contains 30 half-cystine plus cysteine residues determined as cysteic acid after performic acid oxidation. At pH 8.6 the nondenatured protein alkylated with iodoacetic acid in the presence of free thiol has 8 free sulfhydryl groups. The inhibitor is irreversibly inactivated by sulfhydryl reagents and also by removal of free thiol from solutions of the protein. Inactivation by sulfhydryl reagents causes the dissociation of the RNase - inhibitor complex into active RNase and inactive inhibitor.

Amino Acids↗