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Biomedical subjects

S Gordon

Publications and source records attributed to S Gordon.

At least 559 records · Page 31Linked to original sources
PubMed1976

Reassessment of Q waves in left bundle branch block.

This study disputes a number of recent reports claiming that abnormal Q waves or a QS configuration in inferior leads (II, III and AVF) coexisting with left bundle branch block is highly suggestive of, and indeed specific for, myocardial infarction. Five patients reported herein demonstrate disappearance of Q waves in inferior leads on spontaneous reversal of LBBB to normal conduction. This necessitates the conclusion that these Q waves represent a postdivisional conduction variant most closely equivalent to left anterior fascicular block coexisting with predivisional LBBB. Absence of inferior R waves in the five patients demonstrating LBBB is explicable by as little as a 20 msec conduction delay in the posterior fascicle coexisting with a higher grade conduction defect in the anterior fascicle. It is concluded that LBBB with a QS configuration in II, III and AVF cannot be considered diagnostic of inferior wall infarction since it regularly results from impaired conduction of the left anterior and possibly the left posterior fascicle (to a lesser extent), which may be reversible.

Aged↗
PubMed1976

Secretion of macrophage neutral proteinase is enhanced by colchicine.

We have studied the effect of colchicine and related compounds on secretion of enzymes by thioglycollated-elicited mouse peritoneal macrophages in culture. Colchicine stimulated secretion of inducible neutral proteinase activities of elastase (EC 3.4.21.11), collagenase (EC 3.4.24.3), gelatinase (pepsin B; EC 3.4.23.2), and azocaseinase 2- to 6-fold for a period of several days, but inhibited the production and release of lysozyme (mucopeptide N-acetylmuramoylhydrolase; EC 3.2.1.17), a noninducible macrophage secretory product. Parallel changes were observed in cell morphology and secretion after treatment with colchicine, Colcemid, and vinblastine, but not with lumicolchicine, and these effects could be gradually reversed by withdrawal of colchicine. Cytochalasin B also stimulated secretion of elastase 2- to 3-fold but did not influence release of lysozyme. These results demonstrate that tubulin-binding drugs may have opposite effects in macrophages than those usually reported for other experimental systems and also provide evidence for the nonparallel discharge of different macrophage secretion products.

Colchicine↗
PubMed1976

Study of a large Anglo-Saxon family with beta-thalassaemia trait.

Study of a large Anglo-Saxon family with beta-thalassaemia trait revealed evidence of consanguinity, moreover both branches of the family shared a Spanish ancestor. The manifestations of the disorder were varied in severity and yet the degree of severity appeared to breed true within any individual part of the family. Our explanation for the inheritance pattern observed in the family was to postulate the existence of two non-allelic genes influencing the rate of beta-chain synthesis.

Adolescent↗
PubMed1976

Changing clinical, morphological and immunological patterns in chronic lymphocytic leukaemia.

Two cases of chronic lymphocytic leukaemia are presented in which, in the terminal phase of the disease, a population of abnormal lymphocytes similar to those seen in lymphosarcoma cell leukaemia replaced the morphologically normal small lymphocytes observed previously. Immunologically, this change coincided with a striking alteration in the pattern of surface immunoglobulin markers. In both cases, most cells initially carried IgM and in both cases these were replaced by cells carrying IgG as the number of abnormal lymphocytes increased. In addition, the use of anti-delta antiserum in the second case revealed the coexistence of large numbers of IgD-bearing lymphocytes as well. Calculations showed that more than half the cells present at that time must have been carrying both IgD and IgG surface markers.

Cell Membrane↗
PubMed1976

Mitotic variations in the lens epithelium of the frog IV. Studies with isolated anuran pituitary factors.

Proteins corresponding to growth hormone and prolactin have been electrophoretically separated from the pituitary gland of the frog (Rana pipiens berlandieri and Rana catesbeiana). These substances can independently stimulate mitosis in the lenses of animals where it had previously been inhibited by means of hypophysectomy. DNA synthesis is greatly augmented six days after the start of hormone administration to intact animals. Nine days are required before this occurs in hypophysectomized ones. No other anterior pituitary hormone has been found to achieve the effect described. Initial attempts at amino acid analysis, though incomplete, indicate that the two frog hormones are different from each other as well as from their bovine counterparts. Pituitary factors do not affect mitotic activity in either corneal epi or endothelium of the frog.

Amino Acid Sequence↗
PubMed1975

The incidence of Australia antigen in hospital staff members.

A survey of Sydney Hospital staff members for Au antigenaemia was performed during a six-month period in 1972. Nine hundred and forty-six staff members were tested by the immunoelectroosmophoresis (IEOP) method and two asymptomatic chronic carriers were detected. Subsequently, it has been hospital policy to test all new staff members. Eight hundred and ninety additional sera from staff members were obtained and 12 were found to be Au positive. Of these, only one had evidence of liver disease. The results show a slight increase in the incidence of Au positivity in hospital staff members as compared with that of the general Australian population. However, in our series the majority of chronic carriers were immigrants from countries with known high incidence of Au antigen positivity. We therefore postulate that this increase is due not to the hospital environment, but to the carrier's country of origin.

Australia↗
PubMed1975

Secretion of a specific collagenase by stimulated macrophages.

Thioglycollate-stimulated mouse macrophages release a specific collagenase into their medium during in vitro culture. The macrophage collagenase has been characterized as a typical metal proteinase which catalyzes the cleavage of the native collagen molecule into three and one-quarter fragments. The extracellular accumulation and low activity in cell lysates suggest that collagenase is a secretion product of the stimulated macrophage. Prolonged secretion of the enzyme at a constant rate for more than 7 days in culture and its inhibition by cycloheximide provide evidence for biosynthesis in vitro. In contrast, secretion of collagenase is barely detectable from unstimulated macrophages which can, however, be stimulated to secret the enzyme by ingestion and intralysosomal storage of latex particles or dextran sulfate. Macrophages laden with latex, an undigestable particle, continue to release collagenase for at least 20 days. Several established mouse cell lines have also been examined for their capacity to secrete collagenase. Collagenase is one of a class of inducible neutral proteinases by which the activated macrophage can modify its extracellular environment.

Animals↗
PubMed1975

Elastase secretion by stimulated macrophages. Characterization and regulation.

Thioglycolate-stimulated mouse peritoneal macrophages secrete a Proteinase which degrades insoluble elastin. There is little elastase activity in cell lysates but the bulk of the enzyme accumulates extracellularly during culture in serum-free medium. The secretion of elastase is sustained for over 12 days in culture and continued secretion of elastase requires protein synthesis. Unstimulated macrophages secrete very little elastase activity but can be triggered to secrete higher levels of this enzyme by phagocytosis and intracellular storage of latex particles. The macrophages elastase is a distinctive proteinase differing from the elastases of pancreas and granulocytes and is distinct from the other secreted proteinases of macrophages, namely, collagenase and plasminogen activator. The macrophages elastase is a serine proteinase and is inhibited by di-isopropyl phosphoro-fluoridate, ovoinhibitor, EDTA, dithiothretiol, and serum. Its activity is little affected by soybean trypsin inhibitor, turkey ovomucoid and chloromethyl ketones derived from tosyl lysine, tosyl phenylalanine, and acetyltetra alanine. Hydrolysis by macrophage elastase of chromogenic ester substrates for pancreatic elastase could not be detected. Elastase secretion by stimulated macrophages exceeds that by primary and established fibroblast cell strains. It is likely that elastase secretion by macrophages plays a major role in the pathogenesis of chronic destructive pulmonary diseases such as emphysema.

Animals↗
PubMed1975

Ragged-red fibers. A biochemical and morphological study.

Histochemical, ultrastructural and biochemical studies were performed on muscle biopsy specimens from a 30-year-old man with proximal limb weakness. Modified Gomori trichome stains of anterior tibial muscle revealed accumulations of red-staining material in the subsarcolemmal and intermyofibrillar regions of virtually every fiber (ragged-red fibers); these accumulations were rich in oxidative enzymes. Electron microscopy of this muscle showed that the red-staining areas consisted of large collections of abnormal-appearing mitochondria. Mitochondria isolated from the quadriceps muscle showed lack of respiratory control with alpha-glycerophosphate as substrate. However, the lack of respiratory control with alpha-glycerophosphate must be interpreted with caution since the quadriceps muscle was severely degenerated, and biochemical alterations of mitochondria may occur secondary to muscle degeneration itself. Nevertheless, this is the second reported case of lack of respiratory control with alpha-glycerophosphate in a patient with ragged-red fibers. Further interpretation of this defect and its significance must await more studies to determine whether this muscle mitochondrial abnormality is a common finding in the disorders in which ragged-red fibers are encountered.

Adenosine Triphosphatases↗
PubMed1975

The basis for differences in ethanol-induced myocardial depression in normal subjects.

The acute effects of ethanol (ETOH) on cardiac function in 32 normal subjects has been studied utilizing systolic time intervals. Seven (group I) 13 (group II), and 12 subjects (group III), reported an average daily consumption of less than 1 oz, 1-2 oz, and more than 2 oz of ETOH, respectively. Progressively higher control values from group I to group III in PEP, PEPI, ICT and PET/LVET were observed (PEP-I vs PEPI-III: P smaller than 0.05; PEP/LVET-I vs PEP/LVET-II and PEP/LVET-III: P smaller than 0.05). There was progressively less change in these variables following acute ETOH (P smaller than 0.02-0.05 in group I; P equals NS in group III, group II intermediate). This indicates some degree of chronic myocardial impairment in group II and especially in group III, which tends to be proportionate to the degree of chronic ETOH exposure. These data are not necessarily disparate with previous reports of little or even a salutary hemodynamic effect of ETOH in normal subjects. Thus, the relative stability of LVET post ETOH, coupled with the observed increase in heart rate, is consistent with previous reports of ETOH-induced rate-dependent increments in cardiac output with unchanging stroke volumes, in spite of the presence of acute myocardial depression. The observations reported herein demonstrate the probable incremental influence of ETOH consumption in a chain of events which may culminate in alcoholic cardiomyopathy.

Adult↗