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J H Scott

Publications and source records attributed to J H Scott.

At least 37 records · Page 2Linked to original sources
PubMed1984

An osmotic mechanism for exocytosis from dissociated chromaffin cells.

Dissociated chromaffin cells from bovine adrenal medulla were stimulated to secrete epinephrine and dopamine beta-hydroxylase with a variety of secretagogues in a study designed to test the hypothesis that the chemiosmotic lysis reaction of isolated chromaffin granules might in some way be related to the mechanism of release during exocytosis. Increasing the osmotic strength of the incubation medium with either NaCl or sucrose led to suppression of secretion of epinephrine from the cells regardless of whether secretion was induced with veratridine or acetylcholine. Suppression of secretion was approximately exponential with respect to osmotic strength. Epinephrine secretion occurred only if the medium contained a permeant anion such as chloride, and secretion induced by veratridine was suppressed when Na isethionate replaced NaCl in the medium. In an extensive study with different monovalent anions veratridine supported epinephrine secretion according to the following activity series: Br-, I-, NO3- greater than methylsulfate, SCN- greater than Cl greater than acetate much greater than isethionate. A similar series, except for the potency of NO3-, was observed with A23187 as agonist. In general, the anion series for granule lysis was analogous. However, there was a poor quantitative correlation between the anion dependence of chemiosmotic granule lysis and the anion dependence of cell secretion. Anion transport inhibitors such as probenecid and pyridoxal phosphate also inhibited secretion while the stilbene disulfonates were inactive. The ineffectiveness of the stilbene disulfonates further distinguished chemiosmotic granule lysis from cell secretion. Secretion of catecholamines, induced by veratridine or nicotine, a cholinergic agonist, was suppressed when NaCl in the medium was replaced by isosmotic sucrose and unexpectedly low levels of dopamine beta-hydroxylase were observed in some cases. In sum, these properties of secreting chromaffin cells resembled some properties of isolated chromaffin granules incubated in ATP and Cl-, but were different in a number of instances. We, therefore, have interpreted our data to indicate that while some mechanistic relationships may indeed exist between the release event in exocytosis from chromaffin cells and the chemiosmotic lysis reaction characteristic of isolated chromaffin granules, an understanding of the energetics of exocytosis awaits the discovery of reasons for the quantitative differences between the two systems.

Adrenal Medulla↗
PubMed1983

Inhibition of synexin activity and exocytosis from chromaffin cells by phenothiazine drugs.

Synexin activity was found to be inhibited by low concentrations of the phenothiazine drugs, trifluoperazine and promethazine. Both drugs were also similarly effective at blocking nicotine and veratridine-induced catecholamine secretion from cultured chromaffin cells. These data thus indicate that synexin may be a target of phenothiazine drugs when they block secretion from chromaffin cells.

Adrenal Medulla↗
PubMed1983

The management of testicular torsion in the acute pediatric scrotum.

From July 1976 through June 1981, 51 children with acute scrotal pain and swelling underwent surgical exploration. Testicular torsion (27 cases) and torsion of an appendage (18 cases) were the most common diagnoses. In the group with testicular torsion 5 testes were considered unsalvageable and these were removed. The remaining 22 testes, including those of questionable viability, were left in place. The early salvage rate of 81 per cent decreased to 50 per cent due to testicular atrophy found in the late followup period. The attempt to salvage all testes except those with obvious necrosis resulted in minimal morbidity. This approach is discussed in view of recent reports of long-term damage to the contralateral testis when an ischemic testis is not removed initially.

Acute Disease↗
PubMed1983

Abnormal urinalysis in appendicitis.

In a retrospective review of 100 consecutive patients (50 adults and 50 children) with acute appendicitis we correlated abnormal urinalysis (positive occult blood and more than 4 red or white blood cells per high power field) with the operative findings. Abnormal results on urinalysis were noted in 18 adults and 12 children. All urine specimens were collected by the clean-catch method. Abnormal findings were found more frequently in female patients. A majority of patients (53 per cent) with abnormal results on urinalysis had a ruptured or inflamed appendix in proximity to the urinary tract.

Acute Disease↗
PubMed1982

Further characterization of the aggregation and fusion of chromaffin granules by synexin as a model for compound exocytosis.

Synexin was isolated from bovine liver and found to aggregate adrenal chromaffin granules in the same Ca2+-dependent manner as previously described for adrenal synexin. The chromaffin granule aggregating activity of liver synexin was blocked in vitro by the addition of an antibody prepared to the 47,000 molecular weight band extracted from an SDS gel of an adrenal medullary synexin preparation. Chromaffin granules aggregated by synexin fused when exposed to cis-unsaturated fatty acids at concentrations comparable to those released from phospholipids by stimulated secretory cells. The synexin-induced aggregation reaction was blocked by Erythrosin B, a common food coloring, and by the phenothiazine antipsychotic trifluoperazine and promethazine. The aggregation and fusion of chromaffin granules thus appears to be a useful model system for studying synexin from diverse tissues and for testing pharmacologically or toxicologically active substances for effects on secretory systems.

Adrenal Medulla↗
PubMed1981

Legionnaires' disease with severe hypoxemia and saddleback fever.

In the case of Legionnaires' disease described, severe respiratory problems necessitated mechanical ventilatory support, tracheal intubation, and positive end-expiratory pressure. Fever was eliminated with erythromycin therapy but returned after five days, and lung infiltrates spread. After supplementary treatment with other antibiotics and methylprednisolone sodium succinate, both the fever and the infiltrates disappeared. We feel that the multisystem involvement and the recrudescence of fever in our patient emphasize the wide spectrum of characteristics of Legionnaires' disease and the importance of continuation of antibiotics for a prolonged period to eradicate infection.

Adult↗
PubMed1980

Atypical endocarditis due to gram-negative bacillus transmitted by dog bite.

A case of subacute bacterial endocarditis presenting with hemoptysis and late onset of cardiac murmurs, in the absence of pyrexia, was reported. The causative agent was a fastidious, slow-growing, unclassified, gram-negative bacterium, DF-2 (decarboxylase fermenter-2), apparently transmitted by a dog bite. The absence of classic signs of bacterial endocarditis poses a diagnostic challenge and stresses the need for an awareness of atypical presentations of subacute bacterial endocarditis.

Animals↗
PubMed1980

Lyticase: endoglucanase and protease activities that act together in yeast cell lysis.

Yeast lytic activity was purified from the culture supernatant of Oerskovia xanthineolytica grown on minimal medium with insoluble yeast glucan as the carbon source. The lytic activity was found to consist of two synergistic enzyme activities which copurified on carboxymethyl cellulose and Sephadex G-150, but were resolved on Bio-Gel P-150. The first component was a beta-1,3-glucanase with a molecular weight of 55,000. The K(m) for yeast glucan was 0.4 mg/ml; that for laminarin was 5.9 mg/ml. Hydrolysis of beta-1,3-glucans was endolytic, yielding a mixture of products ranging from glucose to oligomers of 10 or more. The size distribution of products was pH dependent, smaller oligomers predominating at the lower pH. The glucanase was unable to lyse yeast cells without 2-mercaptoethanol or the second lytic component, an alkaline protease. Neither of these agents had any effect on the glucanase activity on polysaccharide substrates. The protease had a molecular weight of 30,000 and hydrolyzed Azocoll and a variety of denatured proteins. The enzyme was unusual in that it had an affinity for Sephadex. Although the activity was insensitive to most protease inhibitors, it was affected by polysaccharides; yeast mannan was a potent inhibitor. The enzyme did not have any mannanase activity, however. Neither pronase nor trypsin could substitute for this protease in promoting yeast cell lysis. A partially purified fraction of the enzymes, easily obtained with a single purification step, had a high lytic specific activity and was superior to commercial preparations in regard to nuclease, protease, and chitinase contamination. Lyticase has been applied in spheroplast, membrane, and nucleic acid isolation, and has proved useful in yeast transformation procedures.

Cell Wall↗
PubMed1980

Backache.

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Back Pain↗
PubMed1979

Inheritance and spondylolisthesis: a radiographic family survey.

A radiographic suvey has been carried out of 147 first-degree relatives of forty-seven patients treated in Edinburgh for spondylolisthesis of the fifth lumbar vertebra; twelve patients had the dysplastic (congenital) type and thirty-five an isthmic defect. The survey identified 19 per cent of relatives with spondylolysis, and index patients with each type of spondylolisthesis had relatives with the opposite type. Index patients with the dysplastic form had a higher proportion of affected relatives (33 per cent) than had those with the isthmic type (15 per cent), but both figures were significantly in excess of the estimated frequency for the general population of under 1 per cent and 5 per cent respectively. Spina bifida occulta at the fifth lumbar or first sacral level or both, and lumbosacral segmental defects were commoner amongst all individuals with spondylolysis than amongst unaffected relatives (dysplastic form 94 per cent, isthmic type 32 per cent, unaffected relatives 7 per cent). However, there was no single instance of a neural tube defect (anencephaly, spina bifida with or without meningocele, other generalised vertebral anomalies or spinal dysraphism) amongst 826 first-, second- or third-degree relatives. It is concluded that the developmental defects of the vertebrae associated with spondylolysis are not aetiologically related to the neural tube defects. The one in three risk of spondylolysis to near relatives of patients with the dysplastic form of spondylolisthesis is emphasised in order that the deformity in their sibs and children can be recognised at any early age.

Adolescent↗
PubMed1977

Alpha1-antitrypsin deficiency with diffuse bronchiectasis and cirrhosis of the liver.

The medical literature has emphasized repeatedly the association of alpha1-antitrypsin deficiency with panacinar emphysema and cirrhosis of the liver. Previous reports have linked bronchiectasis with alpha1-antitrypsin deficiency. The present case confirms this association and adds the presence of an hepatic abnormality characteristics of alpha1-antitrypsin deficiency to complete the syndrome. The patient's phenotype was found to be MDuarteZ. It has been suggested that patients with diffuse bronchiectasis should be screened for alpha1-antitrypsin deficiency. We would add that a complete assessment of hepatic function, including liver biopsy, should be carried out in those individuals with reduced levels of alpha1-antitrypsin.

Adolescent↗