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Biomedical subjects

G Wilson

Publications and source records attributed to G Wilson.

At least 343 records · Page 19Linked to original sources
PubMed1976

On the retinal mediation of genetic influences in color preferences of Japanese quail.

The hypothesis that the pigmentation of retinal oil droplets is the morphological target of genetically induced change in the early color preferences of the Japanese quail (C. coturnix japonica) was examined and rejected. Subjects were drawn from the fourth generation of genetic selection for preferences between blue and red, and they were compared according to genetic lines of origin and the presence or absence of pigmentation in their retinal oil droplets. Pigmentation was manipulated by raising parents on carotenoid-free diet. Results indicate a uniform shift toward red preference in all subjects with history of carotenoid deprivation regardless of genetic background, and no change in the magnitude of differences between genetic lines. The data suggest that retinal oil droplets mediate intensity discrimination in the photopic range rather than the perception of variations in light wavelength.

Animals↗
PubMed1976

Infection with minute-colony-forming beta-haemolytic streptococci.

One hundred and thirty-one strains of minute-colony-forming beta-haemolytic streptococci were isolated during the course of routine investigations in clinical bacteriology. Each strain was examined for the presence of polysaccharide antigens of Lancefield's groups A, C, G, and F and characterized in detail as to biochemical and cultural features. On the results of these tests it is concluded that the strains should be placed in the species Streptococcus milleri. The clinical details relevant to the various strains are summarized according to the site of isolation, and their pathological significance is discussed.

Adult↗
PubMed1976

Central circulation during exercise after venesection and reinfusion of red blood cells.

To study central circulation at different levels of hemoglobin (Hb) concentration, five subjects performed submaximal and maximal exercise in three different situations: 1) control, 2) after venesection of 800 ml of whole blood, and 3) after reinfusion of the red blood cells about 30-35 days after venesection. Maximal oxygen uptake (VO2 max) decreased from 4.27 l-min-1) at control to 4.03 l-min-1 after venesection (P less than 0.05) and increased to 4.61 l-min-1 after reinfusion (P less than 0.05). Maximal values on cardiac output (Q), heart rate (HR), and stroke volume (SV) were the same in the three situations. Thus, there was no compensatory increase in Qmax due to the lowered arterial oxygen content (Cao2) after venesection. An increase of the Cao2 (Hb concentration) and a lowering of the Cvo2 contributed equally to the increased VO2 max after reinfusion. At a given submaximal VO2, HR and blood lactates were increased at lowered Hb concentration and decreased at increased Hb concentration over control levels. Correlation coefficient for the change in Q in relation to the acute change in Hb concentration at a given submaximal VO2 was -0.49 (P less than 0.05).

Adult↗
PubMed1976

Color preference in the gibbon.

Color preference was tested by showing 6 colored objects to one adult gibbon. The subject demonstrated both color and position preferences on a modified Wisconsin General Test Apparatus. The blue object and, during some conditions, responses to the subject's right were most preferred.

Animals↗
PubMed1976

Physiological investigations of Swedish elite canoe competitors.

Maximal as well as submaximal heart rate and oxygen uptake were measured during paddling and other types of arm and leg exercise in Swedish elite canoeists. Muscle fiber composition was determined in the canoeists: 4 seniors (22-28 year old) as well as 2 juniors (18 years). Vo2max during treadmill running averaged in the seniors 5.4 1 x min -1 and during arm exercise. Corresponding values for the juniors were 4.7 1 x min -1 and 4.21 x min -1 or 88%. Paddling 500 m resulted in relatively low oxygen uptake, but the highest blood lactate concentrations, whereas 1,000 m gave the highest oxygen uptake but also high blood lactate concentrations. During a 10,000 m race the heart rate was approximately 97% (range 96-98%) of the maximum measured. In nine present and former winners of World Championships or Olympic medals, fiber types were determined in the deltoid muscle. These data indicated that canoeists, who were successful in 500 m races, had a higher percentage of fast twitch (FT) muscle fibers (range 50-59%) than medalists, who competed in 10,000 m races (26-52% FT).

Adolescent↗
PubMed1976

The lacrimal drainage system: pressure changes in the canaliculus.

In order for tears to be removed from the eye, pressure gradients must be created in the ducts which lead to the nose. Blinking is only one of a number of mechanisms potentially capable of doing this. Pressure in the lacrimal canaliculus was recorded during voluntary blinks, tight squeezing of the lids, eye movements, and pressure changes in the nose. The results show that all of these produce pressure changes in the canaliculus.

Eye Movements↗
PubMed1976

Comparison of antitumor activities of pancreatic ribonuclease and its cross-linked dimer.

The cross-linked dimer of bovine pancreatic RNase (M.W. 28,000) is significantly more effective than the monomer in inhibiting tumor development in mice when administered i.p. 1 day after inoculation with sarcoma 180J ascites cells. Animals bearing solid tumors were not affected. In AKR/J mice with advanced leukemia, a single i.p. injection of 100 mug of the dimer led to about 50% reduction in the enlarged lymph nodes and the spleen at 24 hr. The half-life of the dimer in the bloodstream has been determined to be 10 min in rats and 6 min in mice, compared to values of 5 and 3.5 min, respectively, for the monomer. Analyses of the tissues of untreated leukemic mice for RNase and RNase inhibitors show that the tumor tissues are not deficient in RNase activity. Considerations of possible mechanisms of action of the dimer indicate that other basic proteins in this size range may merit examination as cytostatic agents toward transformed cells.

Animals↗
PubMed1975

Study of contrast and modulation mechanisms in X-ray/photon transverse axial transmission tomography.

The ultimate capabibity and a detailed study of contrast and modulation in the context of photon transmission tomography (or computerized transverse axial tomography (CTAT)) is presented. Quantitative evaluation of atomic number, density and electron density of compound materials were made by X-ray fluorescence and combustion analysis, and the attenuation coefficients of photoelectric and Compton effect were measured with high resolution Ge(Li) and Si(Li) detectors. This study provides a guide to an understanding of the high resolution of the currently existing X-ray transmission CTAT scanner (EMI scanner) and to the future development of high resolution scanners.

Brain↗
PubMed1975

Use of a single gibbon in laboratory research.

The high cost of behavioral research with primates may be partially reduced by borrowing animals from a zoo. This report describes such an arrangement involving an adult female gibbon. Operant conditioning data are presented to show that an isolated animal may be used for research.

Animals↗