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Biomedical subjects

R Caldwell

Publications and source records attributed to R Caldwell.

8 recordsLinked to original sources

Cost effective EMIT assays, for drugs of abuse in urine, using the Eppendorf EPOS analyser.

Laboratories with an increasing work load of drug abuse testing require high turnover techniques at low cost. Syva's EMIT system is suitable for modification onto modern automated instrumentation and, with reagent dilution, costs can be significantly reduced. We describe the modification of these assays onto the Eppendorf EPOS analyser which can process 300 samples an hour at a cost of 13p per test.

Cost-Benefit Analysis

Adenocarcinoma of the small intestine in Crohn's disease: a unique finding.

Development of adenocarcinoma of the small bowel is rare. We present this report of a patient with a long-standing history of Crohn's disease who was found to have the 95th reported case of adenocarcinoma developed in the presence of Crohn's. The unique feature of this case is the finding of two distinctly separate carcinomas in the same surgical specimen. With report of this case and a review of the literature, certain characteristics are presented in hopes of raising suspicions sufficiently to detect this malady at an earlier stage.

Adenocarcinoma

Congenital aneurysm of the left atrial wall in infancy.

A 5-month-old male infant with congenital left atrial aneurysm is reported. The youngest patient previously reported was 2 1/2 years old. This case is unusual because the patient was an infant and because of the degree of mitral insufficiency and acute cardiac decompensation observed in the patient.

Heart Aneurysm

A capillary column gas-chromatographic method for the identification of drugs of abuse in urine samples.

This paper describes the application of capillary column gas liquid chromatography (GLC) to the analysis of urine samples for drugs of abuse. A simple basic extraction into butylacetate is followed by temperature programmed analysis from 90 degrees C to 310 degrees C to provide a comprehensive screen for basic drugs. Retention data are presented for approximately 300 compounds. The use of capillary column GLC is compared with packed column methods used previously in this laboratory. The reproducibility of retention data and sensitivity of this analysis for several commonly encountered drugs are presented.

Chromatography, Gas

Divalent cation stimulation of in vitro fibre assembly from epidermal keratin protein.

Keratin was extracted from purified cornified cells of newborn rats in Tris-HCl-buffered 8 M urea containing beta-mercaptoethanol. Microfilaments were assembled in vitro by reducing the ionic strength of buffer and the urea concentration. One millimolar concentration of KCl and NaCl did not affect filament formation, but the same concentration of divalent cations greatly altered this process. CaCl2 and MgCl2 induced gelation of keratin by formation of bundles of birefringent macrofilaments. ZnCl2, CuSO4 and HgCl2 formed greater numbers of macrofilaments and the protein aggregated.

Amino Acids

Activity of alpha-1, 4-glucosidase in furazolidone-induced glycogenosis.

Furazolidone (FZ) at 700 and 800 p.p.m. was added to feed mixtures fed turkey poults two and three weeks posthatching, respectively, to induce acute experimental cardiomyopathy. Poults in the control pen received the same ration but without FZ. From EKG data obtained at 2, 4, and 5 weeks of age, control unaffected and experimental affected poults were selected for sacrifice. Poults were sacrificed by cervical dislocation and appropriate samples of hepatic tissue were removed for assays of activity of alpha-1, 4-glucosidase. Results indicate that enzyme activity in affected FZ-treated poults is similar to that in unaffected control poults. Lack of significant differences in activity of this lysosomal enzyme suggests that FZ-induced glycogenosis may be related to the adult form of idiopathic generalized glucogenosis, the etiology of which remains unidentified.

Animals