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Biomedical subjects

R C Cooper

Publications and source records attributed to R C Cooper.

48 records · Page 3Linked to original sources

Procedure for recovery of enteroviruses from the Japanese cockle Tapes japonica.

The most likely shellfish to be harvested if sportfishing is reinstated in San Francisco Bay is the Japanese cockle Tapes japonica. The virus levels present in these shellfish are unknown and need to be evaluated before the shellfish beds are open. Towards this end, a procedure for recovering and concentrating enteric viruses from these clams has been evaluated. Effective elution of poliovirus from clam tissues was found to occur with pH 9.5 glycine-buffered saline rather than with the pH 7.5 fluid utilized by other investigators on oysters. Poliovirus desorption was combined with Cat-Floc clarification to remove cytotoxicity from clam tissue homogenates. For assay purpose, viruses were concentrated by mixing the glycine supernatant with a beef extract solution, lowering the pH, and suspending the resulting floc in a small volume of phosphate buffer. This simple technique successfully recovered an average of 73% of the poliovirus added to clam homogenates at levels of 93 and 660 plaque-forming units per 100 g. Coxsackievirus B2 was isolated from clams exposed to raw sewage.

Animals↗

Asbestos in drinking water and cancer incidence in the San Francisco Bay area.

Age-adjusted, sex- and race-specific 1969-1971 cancer incidence ratios for the 722 census tracts of the San Francisco-Oakland Standard Metropolitan Statistical Area were compared with measured chysotile asbestos counts in tract drinking waters. The water supplies serving the area have varying contact with naturally occurring serpentine. The t test for multiple regression coefficients and the t test for correlation coefficients showed significant (p less than 0.01) relationships between chrysotile asbestos content of tract drinking water and white male lung, white female gall bladder and pancreas, and peritoneal cancers in both sexes. Of weaker significance (0.01 less than or equal to 0.05) were female esophagus, pleura and kidney, as well as stomach cancers in both sexes. These associations appeared to be independent of income, education, asbestos occupation, marital status, country of origin and mobility.

Adolescent↗

Meningitis caused by Streptococcus dysgalactiae in a preterm infant.

This report describes a case of meningitis caused by a Lancefield group C streptococcus (Streptococcus dysgalactiae) in a 9-week-old infant. Bacteria of this group rarely cause serious infections in man. The organism was identified as a member of Lancefield group C by the acid extraction method and as S. dysgalactiae by biochemical tests. The patient's condition responded well to penicillin and tobramycin therapy, with no obvious neurologic sequelae.

Anti-Bacterial Agents↗

Streptococcus pneumoniae resistant to penicillin and chloramphenicol.

Three cases of meningitis and two of septicaemia were caused by pneumococci resistant to the penicillins/cephalosporins and chloramphenicol. No beta-lactamase was demonstrated in any of the organisms. All three patients with meningitis died, but the patients with septicaemia recovered after being given appropriate antibiotic therapy.

Anti-Bacterial Agents↗

Role of bacteria and protozoa in the removal of Escherichia coli from estuarine waters.

The removal of Escherichia coli from estuarine water was investigated. The survival of E. coli was dependent on the presence of protozoan predators and not on the presence of lytic bacteria. When indigenous protozoa were removed from estuarine water by filtration, the destruction of coliform populations was negligible. In studies designed to prevent the growth of indigenous bacterial populations without affecting protozoan populations, coliform destruction was significant.

Animals↗

Preparation of poliovirus labeled with phosphorus-33.

Phosphorus-33 ((33)P), a weak (0.25 Mev) beta-emitting isotope of phosphorus with a half-life of 25 days, has been used to label poliovirus in cell culture. HeLa cell monolayers were depleted of phosphate and then labeled by incubating at 37 C in a medium (LM) containing about 10 muCi of (33)P as orthophosphate per ml. Labeled cells were infected at a high multiplicity with poliovirus type 1 and incubated for 8 hr in LM medium. Virus from infected cells was then concentrated and purified. Virus purity was confirmed by comparison of virus infectivity and radioactivity after CsCl density gradient centrifugation and by observing purified virus preparations with electron microscopy. With the method described, yields of about 10(10) to 5 x 10(10) plaque-forming units (PFU) of highly purified poliovirus with specific activities of about 3 x 10(-4) to 10(-3) disintegrations per min per PFU have been obtained from 1.5 x 10(8) to 3.0 x 10(8) HeLa cells.

Centrifugation, Density Gradient↗

Electroconvulsive therapy--induced hemodynamic changes unmask unsuspected coronary artery disease.

Electroconvulsive therapy (ECT) is known to produce increases in heart rate and blood pressure during seizure activity due to sympathetic stimulation and systemic catecholamine surges. These intense, brief hemodynamic changes can adversely affect myocardial oxygen supply and demand. In patients with compromised myocardial circulation, ECT can unmask undiagnosed cardiac disease. In this case report, ECT was performed on a 64-year-old white male with negative cardiac history. The patient awakened complaining of chest pain and ST wave depression was noted on the electrocardiogram. Cardiology consultation and cardiac catheterization were followed by coronary artery bypass surgery for significant coronary artery stenosis prior to resumption of ECT treatments. The physiological changes that occur during ECT are discussed, as well as pitfalls in evaluation of these patients for ECT treatment.

Blood Pressure↗

Extracorporeal bypass of the right ventricle and pulmonary trunk using autogenous lungs for oxygenation in the dog.

A technique for right heart bypass using autogenous lungs for oxygenation was evaluated. Venous blood was collected by a catheter placed in the right atrium and caudal vena cava. The blood then passed through the extracorporeal unit and was pumped into the pulmonary circulation. This technique allowed direct surgical exposure of the conus arteriosus, pulmonary valve, and pulmonary trunk. The surgical procedure, plasma hemoglobin levels, platelet and leukocyte counts, arterial blood gas, serum proteins, electrocardiogram, and postmortem findings were evaluated. Although there were significant alterations in many of these parameters, seven of eight dogs were successfully perfused and recovered rapidly from the surgery. One dog died of complications arising from inadequate venous return before bypass was established. On the first postoperative day, the survivors were ambulatory, eating, and having normal bowel function. Right heart bypass may be an effective method to approach lesions involving the conus arteriosus, pulmonary valve, and pulmonary trunk.

Animals↗