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Biomedical subjects

L B North

Publications and source records attributed to L B North.

At least 37 records · Page 2Linked to original sources
PubMed1980

Effects of geometric and screen-film unsharpness in conventional and 350-kVp chest radiography.

Clinical comparison of 350- and conventional 120-kVp techniques indicates that small linear structures, such as small pulmonary blood vessels, are shown better at 120 kVp, due in part to two factors affecting image unsharpness: geometric and screen-film unsharpness. The combined effects of geometric (Ug) and screen-film unsharpness were evaluated for both kVp levels. The total-system modulation transfer function (MTFUg X MTFscreen-film) demonstrates differences in unsharpness under two conditions: (a) when the same screen-film system is used with different magnifications (i.e., extreme planes in the chest) and (b) when different screen-film systems are used for magnification of the midplane of the chest.

Humans↗
PubMed1979

Bone marrow dose in chest radiography: the posteroanterior vs. anteroposterior projection.

The dose to active bone marrow resulting from anteroposterior (AP) and posteroanterior (PA) chest examinations was estimated using an Alderson Rando phantom and extruded lithium fluoride dosimeters. The AP projections resulted in a mean marrow dose range of 1.9-2.6 mrad (0.019-0.026 mGy) as compared to doses for PA projections of 3.4-3.8 mrad (0.034-0.038 mGy) for optimally diagnostic exposure taken at 70, 90, and 120 kVp.

Bone Marrow↗
PubMed1978

Thoracoscopy: technique and results in eighteen patients with pleural effusion.

Eighteen patients with pleural effusion were examined. Nine patients had malignant neoplasm and in one the pleura was diffusely involved. Nine patients had pleural effusion of inflammatory origin. One of these was due to tuberculosis, one to trichinosis and the other seven were nonspecific. Thoracotomy in three of these seven failed to add additional information. All patients tolerated pneumothorax well with equilibration of pleural space and atmospheric pressure.

Biopsy↗
PubMed1977

Effect of irradiation on electrophoretic properties of enzymes in haemopoietic cells of opossum.

5-month-old male opossums were exposed to 5000 rads whole body 60Co radiation and sacrificed at 16, 40 and 90 h following irradiation. Stract gel electrophoretic studies of dehydrogenases of lactate, malate, 6-phospho-gluconate and glucose-6-phosphate and alpha-esterases and acid phosphatase were conducted on the homogenates of spleen and bone marrow cells. Expressions of LDH and G6PD were affected by irradiation in bone marrow and spleen cells.

Animals↗
PubMed1977

Hemodynamic changes in chronic obstructive pulmonary disease.

Right cardiac catheterization was performed in 136 patients with chronic obstructive pulmonary disease. Forty-three of these patients had a second study a mean of 25 months later (range, 18 to 38 months). The changes in hemodynamic data over a period of 25 months were small. The cardiac index decreased 6%, and the mean pulmonary arterial pressure increased 7%. The changes were similar in patients with and those without emphysema.

Blood Gas Analysis↗
PubMed1977

Effect of irradiation on testicular cells of opossum.

Five months old male opossums were exposed to 5000 rd wholebody 60Co gamma-radiation. Testes tissues from animals sacrificed at 16, 40 and 90 hours post-irradiation and from nonirradiated animales were used for enzymatic and histological studies. Electrophoretic pattern of lactate dehydrogenase and glucose-6-phosphate dehydrogenase was slightly disturbed in early hours in irradiated animals, but it did not persist beyond 40 hours postirradiation. Histological study indicates 31% survival of type A spermatogonia suggesting high radioresistance of testes tissue in comparison to other animals.

Animals↗
PubMed1977

Induction of hepatic aryl hydrocarbon hydroxylase in C57BL mice by ionizing radiation.

Inbred strains of C57BL mice were exposed to either 100, 500, or 1000 rads of whole-body irradiation. Another group of mice were given injections of 3-methylcholanthrene only, and a control group had no treatment. Forty-eight hr after treatment, the animals were killed and hepatic aryl hydrocarbon hydroxylase (AHH) activity was measured by spectrophotofluorometer. A comparison of hepatic AHH activity in treated and nontreated groups of mice showed that each treated group had a significantly increased AHH induction compared with the control group. Although radiation appeared to have a dose-related effect on AHH induction, the increase with dose level was not statistically significant.

Animals↗