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Biomedical subjects

G Cooper

Publications and source records attributed to G Cooper.

At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

The role of Ca++ ions in the hypertrophied myocardium [proceedings].

Pressure-hypertrophied right ventricular myocardium (RVH) demonstrates paradoxically increased oxygen consumption (MVO2) related to increased in vitro energy-linked mitochondrial calcium flux. The present experiments were designed to measure mitochondrial Ca++ retention in intact RVH and relate changes in mitochondrial Ca++ metabolism to altered RVH contractile behavior and relaxation. Sixteen cats were pulmonary artery banded and their hearts plus paired controls were perfused with 45Ca Krebs-Henseleit at 30 degrees C, 120 beats/min for 10 min. At Lmax papillary muscles showed reduced active tension, a slower contraction rate, a reduced relaxation rate, a greater time to peak tension and a greater relaxation time. Retained 45Ca of mitochondria was increased from 16.75 + .96nM/mg protein in controls to 20.82 +/- .98 in RVH, (p less than 0.005). This increase in mitochondrial 45Ca retention correlated (r equal to 0.93), (P less than 0.001) with the decreased rate of papillary muscle relaxation. These data show an increased 45Ca retention of mitochondria in pressure-induced RVH and relate this biochemical abnormality to a decreased myocardial relaxation in this state.

Animals↗
PubMedDate not supplied

Carbonaceous meteorites as a source of sugar-related organic compounds for the early Earth.

The much-studied Murchison meteorite is generally used as the standard reference for organic compounds in extraterrestrial material. Amino acids and other organic compounds important in contemporary biochemistry are thought to have been delivered to the early Earth by asteroids and comets, where they may have played a role in the origin of life. Polyhydroxylated compounds (polyols) such as sugars, sugar alcohols and sugar acids are vital to all known lifeforms-they are components of nucleic acids (RNA, DNA), cell membranes and also act as energy sources. But there has hitherto been no conclusive evidence for the existence of polyols in meteorites, leaving a gap in our understanding of the origins of biologically important organic compounds on Earth. Here we report that a variety of polyols are present in, and indigenous to, the Murchison and Murray meteorites in amounts comparable to amino acids. Analyses of water extracts indicate that extraterrestrial processes including photolysis and formaldehyde chemistry could account for the observed compounds. We conclude from this that polyols were present on the early Earth and therefore at least available for incorporation into the first forms of life.

Carbohydrates↗
PubMedDate not supplied

Reduction in regional cerebral blood flow during normal aging in man.

Regional cerebral blood flow (rCBF) was measured by the 133Xenon inhalation method in a selected group of 44 normal non-hospitalized, normotensive subjects aged 19 to 79 years. rCBF was computed as the initial slope index value (ISI). Advancing age was associated with significant reductions in the mean brain and mean hemispheric ISI as well as in individual ISI levels measured from all areas in both hemispheres. Our findings suggest that decline of rCBF is not limited to normal elderly subjects but that it is a progressive phenomenon which begins at an earlier age.

Adult↗
PubMedDate not supplied

A syndrome in commercial turkeys in California and Oregon characterized by a rear-limb necrotizing skeletal myopathy.

A necrotizing skeletal myopathy of rear limbs was diagnosed in 17 flocks of commercial turkeys. The mean mortality attributed to the myopathy was 2.29% (range = 0.13-9.7%) over a mean period of 9.6 days (range = 6-14 days). The mean age of the birds at the time of onset was 7.4 weeks (range = 4-10.5 weeks). Clinically, birds experienced an episode of watery droppings and high-pitched crying, followed by rear-limb paresis or paralysis. Creatine kinase and aspartate aminotransferase were markedly elevated in birds with the myopathy. Grossly, a few birds had pale streaking in the muscles of the thighs and legs. Histologically, acute and subacute degeneration was present in myofibers of the legs, abdomen, thighs, back, and tail. The subacute lesion was characterized by marked sarcolemmal cell proliferation. Feed analyses ruled out selenium deficiency and the presence of mycotoxins as etiologies. Monensin was present in approved usage or only slightly elevated levels. A known potentiating antibiotic was being used concurrently with monensin in only one flock.

Animals↗
PubMedDate not supplied

Experimental transmission of turkey viral hepatitis to day-old poults and identification of associated viral particles resembling picornaviruses.

Turkey viral hepatitis (TVH) was experimentally reproduced in two experiments in 1-day-old poults. In the first experiment, an infectious inoculum was prepared from filtered yolk materials harvested from dead embryonating chicken eggs (ECE) previously inoculated with suspensions of liver and pancreas tissues collected from TVH-affected birds in commercial turkey flocks. One-day-old poults given a yolk-sac inoculation or oral gavage with this preparation developed lesions in the liver and pancreas characteristic of TVH at 20 days postinoculation (PI) in 60% and 14% of the experimentally infected birds, respectively. With the identical inoculum, embryo mortality occurred at 8 and 10 days PI in embryonating turkey eggs (ETE) inoculated into the yolk sac. In the second experiment, an infectious inoculum was prepared from filtered yolk materials from dead ETE harvested in the first experiment. One-day-old poults given a yolk-sac inoculation with this filtered yolk material developed lesions in the liver and pancreas within 5 days PI. At 20 days PI, 67% of the experimentally infected birds had similar lesions. With the inoculum given to these poults, embryo mortality occurred at 6, 8, and 10 days PI in ETE inoculated into the yolk sac. Virus particles 26-28 nm in diameter with icosahedral morphology typical of picornaviruses were identified by EM in the yolk sacs of ETE that died in both experiments, and inoculated ETE that died following passage of filtered suspensions of pancreatic tissues collected from affected birds in the first experiment.

Animals↗
PubMedDate not supplied

Pasteurella anatipestifer infection in commercial meat-type turkeys in California.

A disease outbreak characterized by respiratory signs, occasional neurologic signs, and increased mortality in commercial meat turkeys from four separate companies in central California was investigated in the late summer and early fall of 1986. The disease syndrome affected turkeys from 6 to 15 weeks of age and caused a severe fibrinous pericarditis, perihepatitis, and airsacculitis. Bacteriologic and serologic examinations as well as virus- and chlamydia-isolation attempts initially failed to implicate an etiologic agent. Eventually culture attempts were made in a 5% CO2 incubator, resulting in isolation of Pasteurella anatipestifer. The disease syndrome was reproduced in young turkeys and broiler chicks inoculated with the organism.

Animals↗
PubMedDate not supplied

Phrenic nerve palsy after topical cardiac hypothermia.

Evidence of phrenic nerve paralysis was found in 16 of 172 (9.3%) consecutive adult cardiac surgical patients who survived surgical procedures using topical cardiac hypothermia; two patients had bilateral phrenic nerve paralysis and 14 had left phrenic nerve paralysis. One or more pulmonary complications occurred in 13 of 16 patients (81.3%) with phrenic nerve paralysis while 80 of 156 (56%) had one or more pulmonary complications among patients who had no hypothermic phrenic nerve injury. Average postoperative hospital stay was 13.6 days for patients with left phrenic nerve paralysis, and 22.5 days for patients having bilateral phrenic nerve paralysis. This postoperative complication predominated in males; 15 of 16 (93.8%) of those in our series with phrenic paralysis were males, while 118 of 172 (68.6%) patients were males. Phrenic paralysis did not correlate with the length or degree of systemic hypothermia on cardiopulmonary bypass. No deaths were attributed to phrenic nerve injury. With a minimum of one year follow-up, 12 of 16 patients had return of normal diaphragmatic motion, four had residual paralysis when examined between 12 and 19 months postoperatively.

Adult↗