Biomedical subjects
Publications and source records attributed to J Dawes.
Many members of the Enterobacteriaceae, but not other gram-negative organisms, apparently carry a specific recognition site for the T4 tail tube on their cytoplasmic membranes.
Extracts of Corynebacterium parvum produced by mild hydrolysis of the whole organisms had antitumor activity if given iv 1 day before iv administration of fibrosarcoma cells or if given ip or sc in admixture with these cells. A lipid component seemed responsible for these effects. Unlike whole bacteria, they had little immunotherapeutic activity if given 3 days after sc tumor implantation unless absorbed onto latex. However, organisms treated with acid did not have any immunotherapeutic effect in this system either. The extracts, therefore, did have some antitumor activity, but full activity may depend on the integrity of the whole bacterium.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Various strains of anaerobic coryneforms and the closely related Propionibacteria have been compared in vivo with respect to their anti-tumour activity. Their effectiveness has been correlated with their serological relationship and to some extent with their ability to stimulate the lymphoreticular system. Organisms belonging to Corynebacterium acnes groups I and II and C. avidum group IV were active anti-tumour agents, although of varying effectiveness. These strains are serologically closely related and all produce a soluble cross-reacting antigen. The single C. granulosum group III strain which we tested, an unclassified coryneform, and the classical Propionibacteria did not cross-react with the main group and had little or no anti-tumour activity. At the high dose (0.7 mg) we used, all strains, whether they inhibited tumour development or not, enhanced clearance of colloidal carbon and stimulated production of an inflammatory peritoneal exudate; at lower dosage the results were too variable to permit valid comparison. At the higher dose anti-tumour activity of a strain appeared to correlate best with ability to produce splenomegally and decrease red cell volume in the blood.
Corynebacterium parvum strain 10390 is an antitumor agent and stimulant of the reticuloendothelial system and produces a soluble antigen towards the end of its growth cycle. This material, which is a cell wall component and can also be released from the organism by acid or alkaline hydrolysis, has been purified. It is an acidic polysaccharide of molecular weight 100,000 to 150,000 and contains galactose, glucose, fucose, N-acetylgalactosamine, N-acetylglucosamine, uronic acids, sialic acids, and a small proportion of amino acids. The antigen gives a precipitin reaction with antisera raised against the whole organism and also binds to animal cells. The antigenic determinants are extremely resistant to oxidation, reduction, and enzymatic and chemical hydrolysis, but the single cell-binding site is destroyed by alkali and also by Helix pomatia digestive juice, alginase, and neuraminidase without substantially affecting the molecular weight. This site is inaccessible until the molecule is released from the cell surface. The possibility that the soluble antigen is the biologically active fraction of C. parvum is discussed.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Dose-ranging studies with a batch of factor IX concentrate have been performed in a canine non-stasis model of thrombogenicity. Doses between 50 and 200 IU/kg were infused over a 30 min period, and beagles were found to be more sensitive than greyhounds with regard to subsequent alterations in haemostatic parameters over a 150 min period. In beagles we detected significant increases in plasma fibrin(ogen) degradation products and reduction in fibrinogen concentrations in a dose-related manner after infusion of factor IX concentrate over the range 50-150 IU/kg. Plasma fibrinopeptide A was the most sensitive marker of activation of coagulation with significantly increased levels after factor IX at 50 IU/kg compared with control infusions of albumin. Recovery of infused factor IX was similar to values reported in man. In these experiments, measurement of urinary fibrinopeptide A did not prove to be a useful indicator of thrombogenicity. In conclusion, the beagle non-stasis model will provide a sensitive method to quantify the unwanted thrombogenic activities associated with the use of high doses of certain factor IX concentrates.
Histamine and heparin, both free and cellular, were assayed in the nasal mucosa of 11 atopic and 15 nonatopic patients undergoing turbinectomy for chronic rhinitis. There was no significant difference between the free and cellular histamine levels of the atopic and nonatopic patients. There was also no significant difference between the free heparin levels of atopic and nonatopic patients. Mean cellular heparin was, however, significantly greater in the nonatopic group. This finding, together with the results of mast cell counting, suggests either that in atopic patients heparin stores are already depleted prior to turbinectomy, or that in nonatopic individuals nasal mast cells contain an excess of heparin in nonreleasable stores.
While microalbuminuria indicates the glomerular damage of early diabetic nephropathy, tubular abnormalities also occur at an early stage of diabetic renal disease. Urinary excretion of beta-thromboglobulin (BTG) and N-acetyl-beta-D-glucosaminidase (NAG) was measured in 132 normotensive Type 1 (insulin-dependent) diabetic patients with no evidence of overt renal disease, of whom 35 had microalbuminuria and the remainder had normal urinary albumin excretion. Of 21 patients in whom there was a detectable urinary BTG concentration, only 8 (38%) had a concurrently abnormal urinary albumin excretion. NAG excretion was elevated in 22 (63%) of the 35 patients with microalbuminuria; significant associations were also identified between urinary NAG excretion and smoking habit (x2 = 12.7, p less than 0.001) and glycated haemoglobin (r = 0.49, p less than 0.01). It is concluded that measurement of urinary BTG is not of sufficient sensitivity to be of value in the detection of early diabetic renal disease, but measurement of urinary NAG may be of value in the detection of diabetic nephropathy at a potentially reversible stage.