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Biomedical subjects

D B Cook

Publications and source records attributed to D B Cook.

14 recordsLinked to original sources
PubMed1992

Amplified enzyme-linked immunoassay of human proinsulin in serum (detection limit: 0.1 pmol/L).

We describe an amplified enzyme-linked immunoassay of human proinsulin in serum that detects intact proinsulin and both the 32/33 and 65/66 split forms. The method uses the IgG fraction of a polyclonal antibody raised in a guinea pig against intact proinsulin, which we used to coat plastic microtiter plates. A sandwich was formed with proinsulin by using a monoclonal antibody against C-peptide labeled with alkaline phosphatase. We quantified the reaction by using the enzyme amplification procedure, which detected as little intact proinsulin as 0.1 pmol/L. We found no cross-reactivity with C-peptide in the assay, and decreased recovery attributable to the presence of insulin could be demonstrated only with a 30-fold excess of this hormone over proinsulin.

Alkaline Phosphatase↗
PubMed1991

Partial characterization of plasmids from rabbit isolates of Pasteurella multocida.

Plasmids have not been reported for isolates of Pasteurella multocida from rabbits. We assayed 28 isolates of rabbit P. multocida for plasmids and sought to determine whether or not plasmid presence correlated with clinical or pathologic findings, serotype, toxin production, possession of pili, or biochemical characteristics. Fourteen isolates bore a single 1.6 Md (covalently closed circular form in 0.7% agarose gels) plasmid. An additional isolate had two plasmids which migrated as a closely-spaced doublet, centered around 1.6 Md. Eleven isolates appeared to have identical plasmids, according to Hae III and Hinf I digests. The apparent linear size of this common plasmid in 2% agarose gels was 2.1 Md, as calculated from the sums of the sizes of Hae III or Hinf I digestion fragments. Linearization of the common plasmid with Msp I produced an apparent size of 2.5 Md in 0.7% agarose gels. No correlations between presence of the common plasmid and somatic serotype, toxigenicity, presence of pili, antimicrobial resistance, selected biochemical characteristics, anatomic site from which the bacteria were cultured, or disease status of the host were found.

Animals↗
PubMed1978

Heparin resistance and decreased hepatic triglyceride hydrolase release during long-term estrogen-progestin treatment.

These studies were undertaken to define the mechanism for the depression of post-heparin triglyceride hydrolase activity in women treated with estrogen-progestin oral contraceptives. Six treated and six control women were studied. Total, protamine-inhibited, and protamine-resistant triglyceride hydrolase activities were measured after six different intravenous doses of heparin in each subject in order to determine the dose-response relationships for lipase release. As has been reported during short-term treatment with estrogens, long-term treatment with oral contraceptive agents is accompanied by selective depression of protamine-resistant (hepatic) lipase activity. This depression can be partly reversed by the administration of large heparin doses, but maximally releasing heparin does fail to restore postheparin protamine-resistant activity to control values. These data are compatible with the idea that the releasable pool of hepatic triglyceride hydrolase activity is diminished in women who receive oral contraceptive agents and that the pharmacokinetics of its release are altered in such a way that only relatively high concentrations of heparin displace the enzyme from this pool.

Adult↗
PubMed1977

Seasonal variation of serum 25-hydroxyvitamin D in patients with chronic renal failure treated by regular haemodialysis.

Serum 25-hydroxyvitamin D was measured by a competitive protein-binding assay in 44 normal subjects, 60 uraemic patients on regular haemodialysis at different times of the year and in 13 non-dialyzed uraemic patients. The results obtained indicate that uraemic patients on regular haemodialysis have a mean serum 25-hydroxyvitamin D concentration comparable to controls and that they also exhibit a seasonal variation with a significant reduction during the winter months. However, serum 25-hydroxyvitamin D concentration remained essentially within the normal range and did not reflect the increased incidence of osteomalacia in these patients. In the 13 non-dialyzed uraemic patients, serum 25-hydroxyvitamin D concentrations were lower than in the dialyzed patients, but the explanation is not yet clear. This reduction in serum 25-hydroxyvitamin D was not accompanied by any osteomalacia. The results indicate that deficiency of 25-hydroxyvitamin D in our patients on regular haemodialysis is uncommon and clearly not the explanation of dialysis osteomalacia.

Carrier Proteins↗
PubMed1977

Effects of nomifensine, an inhibitor of endogenous catecholamine re-uptake, in acromegaly, in hyperprolactinaemia, and against stimulated prolactin release in man.

1. Nomifensine, an inhibitor of endogenous catecholamine re-uptake, did not affect the growth hormone (GH) or prolactin levels in patients with acromegaly or hyperprolactinaemia. It does not, therefore, have any therapeutic role in these conditions at the dosage used in this study. 2. It had no effect on thyrotrophin-releasing hormone (TRH)-induced thyrotrophin (TSH) or prolactin release in males, yet caused marked suppression of monoiodotyrosine (MIT)-induced prolactin release in males but not in females. 3. The significant suppression of MIT-induced prolactin release in males is likely to reflect the dopamine (DA) agonist activity of the drug and its lack of effect in the other situations tested could be dose related. 4. It is proposed that the difference in male and female patterns of prolactin response to MIT after nomifensine, could be due to a "damping" effect of oestrogen on the hypothalamic dopaminergic system.

Acromegaly↗
PubMed1975

Effect of surgical trauma on plasma concentrations of cyclic AMP and cortisol.

The response of plasma cortisol and cyclic AMP concentrations to surgical trauma was examined in 7 general surgical patients. Five patients made uncomplicated recoveries and showed peak cortisol levels at 6 hours postoperatively, returning to normal by 24 hours. On patient developed postoperative pneumonia and the plasma cortisol remained elevated up to 48 hours, and the final patient showed no cortisol response at all. The plasma cyclic AMP concentrations showed a consistent rise during the operation itself, which was statistically significant when compared with preoperative levels (P less than 0.0125). Concentrations had fallen to normal by 6 hours in all the cases, except in the patient who developed pneumonia, where the plasma cyclic AMP also showed a prolonged elevation. The significance of these findings requires further elucidation, but the temporal relationship of the cyclic AMP and cortisol peaks would support the hypothesis that cyclic AMP may play a part in the mediation of ACTH release following surgical trauma.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Pasteurella haemolytica as a co-pathogen in pullets and laying hens.

Pasteurella haemolytica was isolated from internal organs of laying hens and pullets of four flocks in which five incidents of increased mortality had occurred. There was inflammation of the trachea in all cases, and infectious laryngotracheitis virus was identified in three of the incidents. Rapid response to antimicrobial therapy was seen in two out of three outbreaks in the pullets. P. haemolytica was regarded as a significant secondary invader in these cases.

Animals↗