Search PubMed⌕ Search

Biomedical subjects

G Cohen

Publications and source records attributed to G Cohen.

At least 397 records · Page 22Linked to original sources
PubMed1978

Protocol for a computed tomography scanner performance repository.

An argument is presented for organization of a Computed Tomography Scanner Performance Repository. Performance data on CT scanners would be distributed in statistical form to the radiological community. A Protocol is presented for the uniform collection of data. Results of exposure, resolution and visibility measurements made by the authors are presented for the EMI 5005/U, Pfizer 0200 FS and General Electric CT/T scanners.

Humans↗
PubMed1978

The effects of the film/screen combination on tomographic image quality.

Several film/screen combinations were studied to evaluate their effect on thin-section tomograms of the inner ear. Hypocycloidal images of a head phantom were subjectively ranked for image quality, and contrast, spatial frequency spectra, and Wiener noise spectra were measured. Resolution appears to be significantly improved when medium-speed screens are used instead of fast, unsharp screens; observers could perceive increased detail through the higher noise of the medium-speed screens. The authors conclude that medium-speed screens yield more diagnostic information than fast, unsharp screens in thin-section tomography of the inner ear.

Humans↗
PubMed1977

Oral infection in immunosuppressed renal transplant patients.

The most common cause of death in patients taking immunosuppressive (IS) drugs is infection. Many of the microorganisms which infect these IS patients may be found in the mouth, but the mouth has not been investigated as a potential source of lethal infection. In view of this, we studied twenty-seven IS patients taking Imuran and prednisone for 6 to 61 weeks and eighteen normal controls. The patients were followed monthly, and the incidence of oral and systemic complications was recorded. There were no deaths due to infection during the 10-month study period. Oral infection occurred as frequently as pneumonia or urinary tract infection. Systemic factors which were related to the development of dental infection were lymphocyte count and length of time on immunosuppressive drug therapy.

Adult↗
PubMed1976

In vivo inhibition of superoxide dismutase in mice by diethyldithiocarbamate.

Superoxide dismutase was assayed by a method which takes advantage of the inhibitory action of superoxide dismutase (or tissues which contain superoxide dismutase) on the rate of autooxidation of 6-hydroxydopamine. Incubation of pure superoxide dismutase of homogenates of brain or liver with 10(-3) M diethyldithiocarbamate for 1.5 hours resulted in total loss of superoxide dismutase activity. Inhibition of superoxide dismutase was not reversed by dialysis, but after dialysis, enzymatic activity was restored with CuSO4. When 1.5 g of diethyldithiocarbamate/kg were injected into mice, the superoxide dismutase activity at 3 hours was decreased by 86%, 71%, and 48%, respectively, in whole blood, liver, and brain. A dose of 0.5 g of diethyldithiocarbamate/kg lowered the superoxide dismutase activity by 42% in liver at 3 hours. A study of the time course for inhibiton of superoxide dismutase in liver after 1.5 g of diethyldithiocarbamate/kg, showed a maximum decrease (81%) within 1 hour, with a slow return to 64% of normal by 24 hours. Inhibition of superoxide dismutase in vivo and in vitro was confirmed with other assay systems based on the autooxidation of pyrogallol or epinephrine or on reduction of cytochrome c or intro blue tetrazolium. Treatment of animals with diethyldithiocarbamate may provide a useful experimental model to study the role of superoxide dismutase in various tissues.

Animals↗