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Biomedical subjects

R B Nelson

Publications and source records attributed to R B Nelson.

At least 37 records · Page 2Linked to original sources
PubMed1986

Effects of cognitive and psychomotor tasks on breath-holding span.

Bartlett (J. Appl. Physiol. 42: 717-721, 1977) demonstrated that a psychomotor task (hand dynamometer) extended breath holds at functional residual capacity (FRC) in a manner comparable to Valsalva and Mueller maneuvers. This led us to the hypothesis that distraction of a subject's attention from dyspneic sensations accounted for Bartlett's findings. This hypothesis was tested by comparing a hand dynamometer task (rubber-bulb squeeze) with a mental performance task (mental arithmetic). Results for tasks performed separately and concurrently in a within-subjects design showed comparable effects, without reaching a FRC breath-hold performance ceiling. Implications of results for effects of nonmechanical and nonchemical factors on respiratory drive are discussed.

Adolescent↗
PubMed1985

A selective increase in phosporylation of protein F1, a protein kinase C substrate, directly related to three day growth of long term synaptic enhancement.

Increased in vitro phosphorylation of the 47 kdalton, 4.5 pI protein F1 was observed in dorsal hippocampal tissue from animals exhibiting long term enhancement (LTE) three days after high frequency stimulation of the perforant pathway, as compared to tissue from low frequency stimulated controls or from unoperated animals. The increase in protein F1 phosphorylation was related to LTE rather than simple activation of perforant path-dentate gyrus synapses. This is the first report of a change in brain protein phosphorylation accompanying synaptic enhancement lasting days. The extent of growth of LTE over the three days following stimulation was directly related (r = +0.66, P less than 0.05) to protein F1 phosphorylation. Among the phosphoproteins studied this relationship between LTE and phosphorylation was selective for protein F1. This suggests that protein F1 may regulate growth of synaptic plasticity for at least a three day period. The mechanism for the LTE-related increase in protein F1 phosphorylation has not been established. However, recent evidence from this laboratory indicates: that protein F1 is phosphorylated by the calcium/phospholipid-dependent protein kinase C; and that kinase C is activated 1 h after LTE. Therefore, the increase in protein F1 phosphorylation following LTE may result from long term activation of protein C kinase.

Animals↗
PubMed1985

Characterization of protein F1 (47 kDa, 4.5 pI): a kinase C substrate directly related to neural plasticity.

We recently demonstrated that long-term potentiation in rat hippocampal formation leads to a selective increase in the phosphorylation of a 47-kDa protein band (F1). The present report provided evidence, using two-dimensional gel electrophoresis, that only one major phosphoprotein in rat is found at 47 kDa under conditions identical to those used in that earlier study. This protein, which we also term F1, has an isoelectric point of 4.5 and is increased in phosphorylation after long-term potentiation. In addition to this identification, we demonstrated in two-dimensional gels that protein F1 is a membrane-enriched kinase C substrate whose phosphorylation is stimulated by Ca2+ and phosphatidylserine. Protein F1 may be equivalent to several reported proteins: a brain-specific, synaptically enriched protein (B-50), a major membrane-bound growth cone protein (pp46), and a fast axonally transported "growth-associated protein" (GAP43; 44- to 49-kDa goldfish optic nerve protein). Protein F1 participation in neural plasticity may thus involve growth occurring at synaptic loci.

Animals↗
PubMed1983

Observed differences in gentamicin pharmacokinetic parameters and dosage recommendations determined by fluorescent polarization immunoassay and radioimmunoassay methods.

Radioimmunoassay (RIA) and fluorescent polarization immunoassay (FPI) methods for quantitative gentamicin serum concentration assay have been shown to be comparable. The purpose of this study was to determine if serum concentration-time data from the same patients assayed by RIA and FPI would provide the same estimates for half-life, elimination rate constant, distribution volume, drug clearance, and gentamicin dose. A total of 99 pre-and postinfusion serum samples were obtained from 30 patients. Samples were divided and assayed by RIA or FPI, and the resultant serum concentration-time data were fitted to a standard one-compartment model. The correlation between the two assay methods was 0.99 (p less than 0.005). A mean difference of 10% was seen in distribution volume, gentamicin clearance, and gentamicin dose from quantitative data from the two methods. These differences were significant (p less than 0.01). Although the two methods appear to be interchangeable, based on in vitro comparison, differences in calculated pharmacokinetic parameters resulted in significant differences in dose recommendations.

Adolescent↗
PubMed1981

Electronically determined platelet indices in thrombocytopenic patients.

Patients with cancer frequently experience thrombocytopenia. Platelet size demonstrated on blood smear can be a clue to the mechanism of thrombocytopenia. New electronic cell counters are capable of determining mean platelet volume (MPV) on whole blood specimens as part of routine complete blood cell counts. The clinical usefulness of MPV and other platelet indices were examined in 87 unselected hospitalized thrombocytopenic patients. Patients with thrombocytopenia resulting from loss or consumption have higher MPVs than do patients with marrow failure. Thrombocytopenic patients also have greater heterogeneity of platelet size than do non-thrombocytopenic patients with normal complete blood cell counts. MPV may become a useful part of routine blood cell counts in hospitalized cancer patients.

Electronics, Medical↗
PubMed1981

Alcoholic liver disease in black men with G6PD deficiency.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency of the type commonly encountered in Afro-American blacks has been associated with an increased severity of viral hepatitis. Decreased activity of the enzyme has been demonstrated in liver tissue of affected individuals. We studied 21 patients with alcoholic liver disease and G6PD deficiency who were identified through the VA Cooperative Study of Sickle Trait and G6PD Deficiency and compared them with 21 black patients with alcoholic liver disease and normal G6PD levels. A trend suggested the severity of liver disease might be less in G6PD-deficient patients. We conclude that G6PD deficiency is not associated with increased severity of alcoholic liver disease.

Adult↗
PubMed1979

Clinical implications of sickle-cell trait and glucose-6-phosphate dehydrogenase deficiency in hospitalized black male patients.

To determine whether sickle-cell trait and glucose-6-phosphate dehydrogenase deficiency influence the course and fatality rates of certain diseases requiring hospitalization, especially those associated with thrombotic phenomena, we conducted a co-operative study of 65,154 consecutively admitted, black male patients in 13 Veterans Administration hospitals. The overall frequency of sickle-cell trait was 7.8 per cent and of glucose-6-phosphate dehydrogenase dificiency 11.2 per cent. Both conditions were present in 0.9 per cent of those examined. There were regional, but no age-dependent, differences in the frequency of sickle-cell trait. Sickle-cell trait had no effect on average age at hospitalization or death, overall mortality, length of hospitalization on medical and surgical wards and frequency of any diagnosis, except essential hematuria and pulmonary embolism. Although statistically significant (P less than 0.001), the differences for the latter were small (1.5 per cent of all patients with normal hemoglobin and 2.2 per cent of patients with sickle-cell trait). Glucose-6-phosphate dehydrogenase deficiency had no adverse effect.

Adult↗
PubMed1977

The role of the pharmacist in drug information for the agricultural sector.

Discussion with veterinarians practicing in southeastern Wyoming suggests that increased pharmaceutical services are needed for the agricultural sector. Such services should include more control of veterinary drugs, informational services, and a forum in which to report untoward responses to drugs. Certain educational and organizational requirements for implementing these services are discussed. Recommendations are advanced that: 1)Some veterinary drugs should be subject to sale by prescription only and be more closely controlled by the pharmacist, 2)A specially in veterinary pharmacy should be established, 3)This specialty should be included as an option on state board examinations and required as a qualification for dispensing animal health drugs, 4)Veterinarians should be appointed to state boards of pharmacy, and 5)Programs in continuing education should be developed to facilitate the entry of existing pharmacists into veterinary pharmacy.

Agriculture↗