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Biomedical subjects

C M Brown

Publications and source records attributed to C M Brown.

At least 199 records · Page 11Linked to original sources
PubMed1985

Fiberoptic gastroduodenoscopy in the horse.

A method of fiberoptic gastroduodenoscopy and biopsy was developed for use in large horses. A 275 cm X 13.5 mm fiberendoscope was used to examine the stomach and proximal portion of the duodenum. Food was withheld for 24 to 48 hours before examination. In more than 50 horses, gastric and duodenal structures were easily visualized. A variety of lesions was detected, including parasitic lesions, gastric ulcers, gastric neoplasia, and pyloric stenosis. Mucosal biopsy specimens were obtained in selected cases.

Animals↗
PubMed1985

EQUIL2: a BASIC computer program for the calculation of urinary saturation.

A BASIC computer program for the calculation of urinary supersaturation with respect to the common kidney stone components is described. In vitro and in vivo tests show that the program described accurately calculates supersaturation. The application of this computer program to urolithiasis research is discussed.

Computers↗
PubMed1985

Acquired cardiovascular disease.

This article reviews the etiology, clinical findings, and significance of diseases of the heart valves, myocardium, pericardium, and great vessels of the horse. Each valve is considered separately from the point of view of murmur production. In addition, the role of the cardiovascular system in the etiology of sudden and unexpected death is considered.

Animals↗
PubMed1984

Effects of calcium on cholinergic-stimulated gastrin release in the rat.

The effects of alterations in availability and access of extracellular media calcium on antral gastrin release were examined in the basal state and in response to cholinergic stimulation in rat antral organ culture experiments. In the presence of either divalent cationic chelator (EGTA) or calcium channel blocker (verapamil, nifedipine), carbachol-stimulated gastrin release was inhibited completely to values that were not significantly different from non-stimulated control. In the absence of added calcium chloride, carbachol stimulated gastrin release during the initial 30 min of culture but not at 69 and 120 min of culture. Inhibition by EGTA and verapamil of carbachol-stimulated gastrin release during the initial 30 min of culture suggests, but does not prove, that these agents may also effect intracellular availability and movement of calcium. Cholinergic stimulation of gastrin release demonstrated a concentration-dependent relationship with extracellular calcium: optimal culture media calcium concentration was 1 mM. In conclusion, these studies indicate that cholinergic stimulation of the gastrin cell requires availability of extracellular calcium.

Animals↗
PubMed1984

Differences in the control of virus mRNA splicing during permissive or abortive infection with influenza A (fowl plague) virus.

Spliced transcripts of influenza A (fowl plague) virus (FPV) RNA (vRNA) segments 7 and 8 accumulate to a much greater extent during non-productive infection of mouse L cells, than they do during productive infection in primary chick embryo fibroblasts (CEF). Virus-specific protein synthesis, or a consequent event in virus replication appears necessary to promote splicing of vRNA segment 8-encoded mRNAs in both cell types, and of vRNA segment 7-encoded mRNAs in CEF. In L cells, however, splicing of the segment 7-encoded mRNAs seems to be independent of such virus-specific control. This observation is discussed in relation to the defect in expression of vRNA 7 which has been observed previously in FPV-infected L cells, and which is thought to account for the failure of virus replication.

Animals↗
PubMed1984

L-Rhamnose utilisation in Salmonella typhimurium.

L-Rhamnose is degraded by strains of Salmonella typhimurium by isomerisation to L- rhamnulose , phosphorylation to L- rhamnulose -1-phosphate and cleavage to lactaldehyde and dihydroxyacetone phosphate. The enzymes involved are, respectively, rhamnose isomerase ( RhaI ), rhamnulokinase ( RhuK ) and an aldolase (Ald). Strains able to grow rapidly on L-rhamnose contained a high-affinity uptake system for 3H-L-rhamnose that was induced by L-rhamnose and repressed by D-glucose. The synthesis of RhaI and RhuK was also induced by L-rhamnose but was not repressed by D-glucose. The synthesis of Ald was constitutive. Data are presented on some strains which grow very slowly on L-rhamnose and on others which do not utilise it.

Mutation↗
PubMed1984

3-methylindole as a model of equine obstructive lung disease.

3-methylindole was administered orally and intravenously to horses and ponies in order to determine the ability of this chemical to provide a model of equine pulmonary disease. Both routes produced a severe and sometimes fatal pulmonary disease, characterised by bronchiolitis. Clinical signs developed 48 to 72 h after dosing and were most severe between Days 4 and 10 post dosing. Intravenous administration of 3-methylindole produced lung injury more rapidly and at a lower dose rate than the oral route. It is suggested that the respiratory condition induced by this chemical could become a method for standardisation of lung function techniques and interpretation in equine obstructive pulmonary disease.

Animals↗
PubMed1984

Staphylococcal lysate fails to elicit nonspecific immune enhancement in a simulated surgical infection.

Staphylococcus aureus produces a delayed-type hypersensitivity reaction, which results in some degree of nonspecific immune enhancement. The authors chose to observe the effects of staphylococcal vaccine (staphage lysate) as a possible potentiator of nonspecific immunity. The experiments were performed in a well-known model simulating surgical infection. The experimental results do not support the previously proposed hypothesis that staphylococcal vaccine improves the immune response to a bacterial challenge.

Animals↗
PubMed1983

Adenosine relaxes the aorta by interacting with an A2 receptor and an intracellular site.

The purpose of this study was to determine whether the adenosine receptor that mediates relaxation of the noradrenaline-contracted guinea-pig aorta is of the A1 or A2 subtype. 5'-N-ethylcarboxamide adenosine (NECA) and 5'-N-cyclopropylcarboxamide adenosine (NCPCA) were about 100 times more potent as relaxants of the aorta than L-N6-phenylisopropyladenosine (L-PIA) and N6-cyclohexyladenosine. L-PIA was 3 times more potent than D-PIA. These relaxations were not altered by the purine transport inhibitor dipyridamole, but were attenuated by the cell surface adenosine receptor antagonist 8-phenyltheophylline. Adenosine and 2-chloroadenosine differed from NECA and NCPCA since they evoked greater maximal relaxations and their submaximal responses were less sensitive to blockade by 8-phenyltheophylline. These differences were abolished by dipyridamole which indicates that they were due to an intracellular action of adenosine and 2-chloroadenosine. The intracellular 'P-site' agonist, 9-beta-D-xylofuranosyladenine evoked small relaxations that were attenuated by dipyridamole but were unaffected by 8-phenyltheophylline. These results indicate that adenosine can relax the aorta via interactions with a cell surface A2 receptor and with an intracellular site.

Adenosine↗
PubMed1983

Adenosine A1 receptor mediated inhibition of nerve stimulation-induced contractions of the rabbit portal vein.

The aim of this study was to determine whether the adenosine receptor that inhibits adrenergic neurotransmission in the rabbit portal vein is of the A1 or the A2 subtype. Isometric contractions of the isolated vein were evoked by electrical field stimulation and by exogenous noradrenaline. Low concentrations of adenosine, and a number of analogues inhibited the response evoked by field stimulation but had no effect on those evoked by noradrenaline. The order of inhibitory potency was: L-N6-phenylisopropyladenosine (L-PIA) = N6-cyclohexyladenosine (CHA) = 5'-N-cyclopropylcarboxamide adenosine (NCPCA) greater than or equal to 5'-N-ethylcarboxamide adenosine (NECA) = 2-chloroadenosine greater than adenosine greater than D-PIA. The difference in potency between the stereoisomers L- and D-PIA was about 60 fold. The purine transport inhibitor dipyridamole potentiated the inhibitory effect of adenosine but not that of its analogues. The inhibitory responses evoked by adenosine and its' analogues were attenuated by the adenosine antagonist theophylline. These results indicate that adenosine selectively inhibits contractions of the rabbit portal vein evoked by adrenergic nerve stimulation via activation of an adenosine A1 receptor.

Adenosine↗