Biomedical subjects

J Holbrook

Publications and source records attributed to J Holbrook.

23 records · Page 2Linked to original sources

PubMed1986

Development of copper deficiency in rats fed fructose or starch: weekly measurements of copper indices in blood.

Copper deficiency was induced in weanling rats fed diets whose sole source of carbohydrates was starch or fructose for 7 weeks. Conventional parameters of copper status, plasma copper concentrations, ceruloplasmin activity, and erythrocyte superoxide dismutase (SOD) activity were longitudinally monitored weekly to follow the development of the deficiency and to correlate these indices with the degree of severity of the deficiency. Although 30% of the rats fed a copper-deficient fructose diet died and no deaths occurred in rats fed the copper-deficient starch diet, plasma copper, ceruloplasmin, and SOD activities were reduced to a similar extent in all rats fed copper-deficient diets regardless of the type of dietary carbohydrate. Thus, none of the indices used accurately reflected the greater degree of deficiency or mortality in rats fed the fructose diet deficient in copper. The results of the present study underscore the need for more sensitive tests or alternative parameters to assess copper status in living animals.

Animals↗

PubMed1984

The institutional chaplain: constructing a role definition.

Reports on a questionnaire survey of members of the Omaha Nebraska Area Institutional Chaplains' Association and the Nebraska State Chaplain's Association. Develops a typology of the role of the hospital chaplain based on findings which indicate that chaplains see themselves as (1) counselors, (2) professionals, and (3) religious functionaries. Notes that these perceptions are often at dissensus with relevant publics, and interprets the role of definitions in terms of secularization and social structure principles. Discusses and suggests ways of addressing role differences in view of current changes in health care developments.

Chaplaincy Service, Hospital↗

PubMed1979

Prison health and medical education.

Prison health has long been neglected as an area of serivice by organized medicine and a site for clinical education by health science centers. The University of New Mexico Health Science Center offers an elective, weekly clinical experience for preclinical medical students, senior nursing students, and senior pharmacy students at a prison facility in need of medical services. Students' reaction to the prison experience was strongly positive. Most developed empathy toward the inmates and a greater understanding of prison health problems. Inmates rated the student service highly and requested its continuation. This community health education experience has provided a noncontractual model of a university-prison health alliance.

Ambulatory Care Facilities↗

PubMed1978

Malate dehydrogenase of the cytosol. A kinetic investigation of the reaction mechanism and a comparison with lactate dehydrogenase.

1. The mechanisms of the reduction of oxaloacetate and of 3-fluoro-oxaloacetate by NADH catalysed by cytoplasmic pig heart malate dehydrogenase (MDH) were investigated. 2. One mol of dimeric enzyme produces 1.7+/-0.4 mol of enzyme-bound NADH when mixed with saturating NAD+ and L-malate at a rate much higher than the subsequent turnover at pH 7.5. 3. Transient measurements of protein and nucleotide fluorescence show that the steady-state complex in the forward direction is MDH-NADH and in the reverse direction MDH-NADH-oxaloacetate. 4. The rate of dissociation of MDH-NADH was measured and is the same as Vmax. in the forward direction at pH 7.5. Both NADH-binding sites are kinetically equivalent. The rate of dissociation varies with pH, as does the equilibrium binding constant for NADH. 5. 3-Fluoro-oxaloacetate is composed of three forms (F1, F2 and S) of which F1 and F2 are immediately substrates for the enzyme. The third form, S, is not a substrate, but when the F forms are used up form S slowly and non-enzymically equilibrates to yield the active substrate forms. S is 2,2-dihydroxy-3-fluorosuccinate. 6. The steady-state compound during the reduction of form F1 is an enzyme form that does not contain NADH, probably MDH-NAD+-fluoromalate. The steady-state compound for form F2 is an enzyme form containing NADH, probably MDH-NADH-fluoro-oxaloacetate. 7. The rate-limiting reaction in the reduction of form F2 shows a deuterium isotope rate ratio of 4 when NADH is replaced by its deuterium analogue, and the rate-limiting reaction is concluded to be hydride transfer. 8. A novel titration was used to show that dimeric cytoplasmic malate dehydrogenase contains two sites that can rapidly reduce the F1 form of 3-fluoro-oxaloacetate. The enzyme shows 'all-of-the-sites' behaviour. 9. Partial mechanisms are proposed to explain the enzyme-catalysed transformations of the natural and the fluoro substrates. These mechanisms are similar to the mechanism of pig heart lactate dehydrogenase and this, and the structural results of others, can be explained if the two enzymes are a product of divergent evolution.

Chemical Phenomena↗

PubMed1976

The binding by an NAD-affinity matrix of contaminating dehydrogenases in cytochrome c oxidase preparations.

An NAD-matrix is capable of the separation of three contaminant reductase activities from highly purified beef heart cytochrome c oxidase. Non-specific binding of cytochrome c oxidase occurs as well. When the matrix is saturated with respect to the non-specific binding, continued binding of the reductases can be observed. As a consequence of equilibration with the matrix, the turnover numbers of the unbound cytochrome c oxidase are increased.

Chromatography, Affinity↗