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Biomedical subjects

R J Jackson

Publications and source records attributed to R J Jackson.

At least 199 records · Page 11Linked to original sources

Processing of the encephalomyocarditis virus capsid precursor protein studied in rabbit reticulocyte lysates incubated with N-formyl-[35S]methionine-tRNAfMet.

Translation of encephalomyocarditis virus RNA in rabbit reticulocyte lysates in the presence of N-formyl-[(35)S]methionine-tRNA(f) (Met) revealed that a small polypeptide is cleaved from the N-terminus of the capsid protein precursor, preA, by virus-coded protease activity. Therefore, this N-terminal segment comprising the translation initiation site is not conserved in any of the mature capsid proteins.

Animals↗

Retroperitoneal pseudolymphadenopathy.

Computed tomography is very sensitive in detecting enlarged retroperitoneal lymph nodes. Several structures such as vessels, bowel loops, fibrous tissue and hemorrhage can simulate pathologic retroperitoneal nodal enlargement. A thorough awareness of the normal retroperitoneal anatomy will help in correct interpretations and may obviate the need for more invasive diagnostic procedures.

Adult↗

Identification of gastric cyclic AMP binding proteins.

The photoaffinity ligand 8-azidoadenosine 3',5-monophosphate was employed to label cAMP binding proteins in both fractionated and freeze-thawed rabbit gastric glands. Fractionated glands incorporated the azido-cAMP label primarily into two cytosolic proteins with apparent molecular weights of 58 000 and 48 000. No enrichment of label was found in fractions containing basolateral or apical membranes. DEAE-cellulose chromatography of the cytosolic proteins resulted in the separation of two cAMP-dependent protein kinase peaks. Azido cAMP labelling of each peak suggested the initial peak contained type I cAMP-dependent protein kinase while the second peak contained the type II kinase. Labelling of 'resting' gastric glands resulted in radioactive proteins of apparent molecular weights of 58 000 and 48 000. When gastric glands were stimulated to produce acid by the addition of 10(-4) M histamine or 1 mM dibutyryl cAMP there was 32-44% dimunition of ligand incorporation compared to control glands. The results strongly suggest that histamine-mediated stimulus-secretion coupling in gastric glands involves activation of parietal cell cAMP-dependent protein kinases.

1-Methyl-3-isobutylxanthine↗

Health screening of Indochinese refugee children.

The first 100 Indochinese refugee patients screened at Oakland (Calif) Children's Hospital had a remarkably high incidence of treatable infectious and parasitic diseases. The PPD skin tests were positive in 28%, and stool parasites were present in 65%. There were wide differences among the various ethnic groups in prevalence of stool parasites, anemia, and hemoglobin E trait, with a higher rate among Cambodians accounting for these differences. There were also differences in stool parasite patterns when the refugees were separated by ethnic origin. Cambodians had predominantly hookworm and Strongyloides, Laotians harbored hookworm and Trichuris, and Vietnamese were infested with Trichuris and Giardia. Malaria. Pott's disease, and congenital syphilis were among the uncommonly encountered diseases. Results of screening will vary with ethnic origin, but health screening has a high yield for all Indochinese refugees.

Adolescent↗

Use of plasma membrane vesicles.

A summary of current methodologies employed to obtain and characterize epithelial plasma membrane vesicles is presented. Particular emphasis is placed on techniques to evaluate such parameters as homogeneity, tightness, orientation, and the percentage of active vesicles in a given vesicular population. Examples of isotopic, osmotic, and various probe techniques useful for quantitation of transport events and associated electrical phenomena are illustrated. Finally, the unique problems intrinsic to purification and reconstitution of transport proteins are briefly discussed.

Animals↗

Analysis of phosphorylation of protein synthesis initiation factor eIF-2 by two-dimensional gel electrophoresis.

We describe a method for examining the state of phosphorylation of initiation factor eIF-2 in reticulocyte lysates. The procedure involves incubation of the lysate with iodo[1-14C]acetate in 8.5 M urea, and fractionation of the labelled proteins by two-dimensional acrylamide gel electrophoresis. This approach has been used to show that haem deficiency, double-stranded RNA, and oxidised glutathione, which all inhibit the initiation of protein synthesis in an analogous manner, all cause a net increase in the level of phosphorylated eIF-2 in the complete lysate protein synthesis system.

Animals↗

Epidemic Yersinia enterocolitica infection due to contaminated chocolate milk.

In September and October, 1976, an outbreak of illness due to chocolate milk contaminated with Yersinia enterocolitica resulted in hospitalization of 36 children, 16 of whom had appendectomies. Infection with Y. enterocolitica serotype 0:8 was demonstrated in 38 ill persons. Sixty-one per cent of the persons who were infected had a titer greater than 1:160 OH agglutinins to serotype 8 yersinia, whereas 48 per cent of the hospitalized children had a fourfold change in agglutinin titer. An epidemiologic investigation demonstrated that illness was associated with drinking of chocolate milk purchased in school cafeterias, and Y. enterocolitica 0:8 was subsequently isolated from the milk. The investigation suggested that the bacterium was introduced at the dairy during the mixing by hand of chocolate syrup with previously pasteurized milk.

Adolescent↗