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Biomedical subjects

C Buchanan

Publications and source records attributed to C Buchanan.

At least 109 records · Page 6Linked to original sources
PubMed1989

Mechanism of IGF-I-stimulated glucose transport in human adipocytes. Demonstration of specific IGF-I receptors not involved in stimulation of glucose transport.

We demonstrate the presence of specific insulinlike growth factor I (IGF-I) receptors in human adipocytes. Competition studies with 125I-labeled IGF-I and unlabeled IGF-I, IGF-II, and insulin showed the specificity of 125I-IGF-I binding to the IGF-I receptors in adipocytes, membranes, and partially purified detergent-solubilized extracts. The monoclonal antibody to the IGF-I receptor (alpha-IR3) inhibits 125I-IGF-I binding and immunoprecipitates the IGF-I receptor. In addition, the alpha-subunit of IGF-I receptor is approximately 10,000 Mr larger than the alpha-subunit of insulin receptor, and IGF-I stimulates phosphorylation of the beta-subunit of the IGF-I receptor. IGF-I stimulates basal glucose transport in human adipocytes, but the concentrations of IGF-I required for half-maximal and maximal stimulation of glucose transport are 800- and 1000-fold greater than that of insulin. The possibility of IGF-I stimulating glucose transport by interacting predominantly with insulin receptors is suggested by data showing that 1) IGF-I competes with insulin-binding sites, 2) there is a lack of an additive effect with IGF-I and insulin in stimulating glucose transport, 3) alpha-IR3, which specifically inhibits IGF-I binding, does not inhibit IGF-I or insulin-stimulated glucose transport, 4) insulin-receptor antibody MA-10 inhibits IGF-I and insulin-stimulated glucose transport, and 5) IGF-I stimulates insulin-receptor autophosphorylation, although its effect is markedly decreased compared with insulin. In summary, human adipocytes possess specific IGF-I receptors. However, IGF-I stimulates glucose transport predominantly by interacting with the insulin receptor.

Adipose Tissue↗
PubMed1988

Bioactivity and immunoactivity of growth hormone during dynamic testing of patients with acromegaly.

We have used the Nb2 cell proliferation bioassay for lactogenic hormones to investigate the biological activity of hGH in sera of patients with acromegaly. The specificity of the assay has been improved by the use of monoclonal antibodies to block the activity of individual lactogenic hormones. Disease activity in patients was assessed by scoring signs and symptoms, and by measuring IGF-I concentrations in some patients. Patients with a wide spectrum of disease activity were studied using a TRH test. hGH concentrations were measured by bioassay, RIA and immunoradiometric assay (IRMA) at 0, 20 and 60 min after injection of TRH. There was a high degree of correlation between log10 of all hGH concentrations measured by bioassay and RIA (r = 0.995, P less than 0.0001), between bioassay and IRMA (r = 0.990, P less than 0.0001), and between RIA and IRMA (r = 0.995, P less than 0.0001). In contrast to previous reports, we found no evidence for changes in the bioactivity of hGH secreted after pituitary stimulation.

Acromegaly↗
PubMed1988

Severe soft-tissue injury following intravenous infusion of phenytoin. Patient and drug administration risk factors.

From April 8, 1982, through June 1984, 11 patients in a single hospital experienced 17 episodes of limb edema and discoloration after the intravenous (IV) administration of phenytoin sodium (Dilantin). One patient required a below-the-elbow amputation; all other patients recovered. No single drug lot was implicated. A case-control study was performed using three controls for each case; controls received IV infusions of phenytoin and were hospitalized close in time to the case patients. Compared with controls, patients with reactions were more often female and elderly and had underlying cardiovascular disease. Affected patients also received phenytoin through an IV catheter smaller than 20 gauge (50% vs 6%), at a rate greater than 25 mg/min (63% vs 19%), and in two or more IV infusions of phenytoin given "IV push" at the same site (81% vs 24%). High-risk patients require careful monitoring and stricter guidelines for the IV administration of phenytoin.

Age Factors↗
PubMed1987

Salicylate and mitochondrial monoamine oxidase function in Reye's syndrome.

The main objective of this investigation was to study the effect of salicylate on platelet mitochondrial monoamine oxidase (MAO) activity isolated from blood of two patients with Reye's syndrome. Comparative studies were made with hospitalized children without Reye's syndrome (n = 27) and healthy children (n = 19) serving as controls. Platelet MAO was measured by a radioenzymatic technique with [14C]tyramine as a substrate. The results of this study showed that salicylate (1.0 mM) caused an appreciable inhibition of the platelet MAO activity of patients with Reye's syndrome at the onset of the illness. This was demonstrated by a greater than 50% reduction in enzyme maximum velocity (Vmax) value. The salicylate MAO-inhibitory effect was maintained throughout the duration of the illness. Salicylate had only a minimal MAO-inhibitory effect on platelets isolated from blood of recovered Reye's syndrome patients, healthy controls, and non-Reye's hospitalized children, and no apparent effect on enzyme Vmax values. These preliminary findings suggest that salicylate-induced mitochondrial injury may affect MAO function in children with Reye's syndrome.

Adolescent↗
PubMed1986

Adverse drug reaction reporting system: developing a well-monitored program.

The spontaneous reporting of adverse drug reactions (ADRs) at the St. John's Hospital and Memorial Medical Center was well below that reported in the literature. After review of procedures for reporting of ADRs at these institutions, the authors developed a system that was approved by their joint P & T Committee. The ADR reporting program developed uses concurrent monitoring of most hospital inpatients and a retrospective review of all emergency room patients. In the year after program implementation, 162 ADR reports were documented. From this program, a group of serious ADRs to one agent was identified and reported, both to the Food and Drug Administration and to the manufacturer. A well-developed ADR monitoring program may lead to heightened physician and nurse awareness and early problem identification, possibly decreasing morbidity for hospitalized patients.

Documentation↗
PubMed1986

Supplemental chloralose anesthesia in morphine premedicated dogs.

This study evaluated the cardiorespiratory stability of six dose-regulated, 12-hour, chloralose anesthetic maintenance protocols. Thirty mongrel dogs were premedicated with morphine sulfate (5mg/kg) and anesthetized with an induction dose of chloralose (80mg/kg). Fifteen animals were permitted to breathe spontaneously and 15 animals were ventilated mechanically to maintain a constant arterial pCO2 (40 +/- 5 mmHg). The spontaneously breathing dogs were separated into three groups in which animals (n = 5) were given different bolus doses of supplemental anesthetic. Initially the spontaneously breathing animals were hypoxemic, acidemic and hypercapnic. No consistent hemodynamic difference was noted among these groups. The mechanically ventilated animals were also divided into three groups that received varying doses of supplemental chloralose by constant infusion. Significant (p less than 0.01) myocardial depression was noted in the heavy-dosed animals by the third hour. Systolic pressure decreased 44%, pulse pressure decreased 37% and peak left ventricular dP/dt decreased 52%. All heavy-dosed animals expired before the eighth hour. Although these data suggest that morphine-premedicated, chloralose-anesthetized animals generally provide a stable cardiopulmonary model, high-dose chloralose supplementation depressed ventilation and produced a dose-dependent cardiotoxicity.

Anesthesia↗
PubMed1984

Quantitative description of two sitting postures. With and without a lumbar support pillow.

This study investigated changes in angular position of the forearm, upper arm, pelvis, trunk, neck, and head during relaxed sitting with and without a lumbar support pillow. Data markers were placed on specified anatomical sites of 19 healthy adults (10 women and 9 men) who then had sagittal plane photographs taken in the two different sitting postures. Using a protractor, we measured segment angles with respect to the horizontal on all photographs. Use of the lumbar support pillow during relaxed sitting showed a significant difference (p less than or equal to .05) in the segment angles of forearm, upper arm, pelvis, and trunk. The use of a lumbar support pillow to change sitting posture is supported.

Adult↗
PubMed1976

Six-month pharmacy technician training program at a community college.

A six-month pharmacy technician training program at a community college is discussed. Establishment of the program, recruitment and screening of applicants, and the curriculum are described. Also discussed are the advantages of community college training, the program's pharmacist advisory committee, contracts with hospitals that provide practical experience, reaction of state pharmacy organizations to the program, and the employment record of graduates. It is suggested that short, effective pharmacy technician training programs should be established in community colleges to supply high quality supportive personnel to hospital pharmacies. A national testing and certification program for pharmacy technicians is recommended.

Allied Health Personnel↗