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Biomedical subjects

R Bishop

Publications and source records attributed to R Bishop.

At least 73 records · Page 4Linked to original sources
PubMed1988

The present status of rotavirus vaccine development.

Rotavirus infection is one of the most important causes of morbidity in young children throughout the world. The high associated mortality in Southeast Asia (and elsewhere) warrants the development of a vaccine. It is probable that most of the life-threatening watery diarrhoea due to rotavirus infection occurs as a result of primary infection in children aged 6-18 months after protection due to maternal antibody has diminished. Thus rotavirus vaccines are targeted at young infants from birth to 3 months of age. At present three candidate rotavirus vaccines (RIT-4237, MMU-18007, WC3) have undergone trials in young children. A bovine rotavirus strain (RIT-4237), was shown to be safe, immunogenic and efficacious in prevention of severe rotavirus diarrhoea in young children in Finland. However it was found to be weakly immunogenic in infants in developing countries, and to have only low efficacy in prevention of disease. A simian rotavirus strain (RRV, MMU-18006) has proved to be highly immunogenic and its reactinogenicity to be diminished by pre-existing maternal antibody (in infants aged 1-4 months). It has high efficacy against clinically severe rotavirus infection. However protection is homotypic against human serotype 3 only so that eventually a multivalent vaccine incorporating reassortant rotavirus strains that protect against human serotypes 1, 2, 4 (and other newer serotypes) may be required. It is hoped that, once safe immunogenic and protective candidate rotavirus vaccines are identified, they can be administered in an acceptable form with no alteration to existing immunization schedules.

Adult↗
PubMed1985

Enteroclysis in the diagnosis of chronic unexplained gastrointestinal bleeding.

In a six-year period (1977-83), lesions were identified by enteroclysis in 26 patients with melena or recurrent gastrointestinal bleeding undiagnosed by other modalities. These included nine Meckel's diverticula, three metastatic lesions, three primary carcinomas, one lipoma, four leiomyomas, five surgically created blind pouches, one carcinoid, and one idiopathic dilatation of the ileum. Our experience suggests that, when the standard diagnostic procedures used to investigate chronic gastrointestinal blood loss are unrevealing, enteroclysis should be performed. The method is fast, accurate, is done in one sitting, and can be productive in the diagnostically difficult patient.

Adenocarcinoma↗
PubMed1985

Safety of 9.3-GHz microwave radiant heating for possible caloric supplement and medical treatment.

The hematological and blood-chemistry effects of chronic microwave radiation on unrestrained rhesus monkeys trained to expose their face and eyes to 9.3GHz microwave radiation at an average incident power density of 150 or 300mW/cm2 are reported. Only inconsistent transient effects were found. The lack of significant hematological effects, together with the lack of ocular or behavioral changes reported earlier, support the idea that microwave frequencies in the range of 10GHz may be safe to use for caloric supplement of hypothermic individuals and medical patients.

Animals↗
PubMed1985

Protein phosphorylation in a tetradecanoyl phorbol acetate-nonproliferative variant of 3T3 cells.

The 3T3-TNR9 cell line is a variant of Swiss 3T3 cells which does not respond mitogenically to tumor promoters, but does respond mitogenically to epidermal growth factor, fibroblast growth factor, and serum. To elucidate differences between tumor promoters and polypeptide mitogens in the pathway(s) of mitogenesis which might be responsible for the nonresponsiveness of the 3T3-TNR9 cells, we have examined in these cells the early protein phosphorylation events known to be associated with mitogenesis in the parental 3T3 cells. We find that the 3T3-TNR9 cells display levels of tetradecanoyl phorbol acetate binding and of a calcium- and phospholipid-dependent protein kinase activity which are at least the equal of those seen in the parental 3T3 cells, implicating some postreceptor event in the nonmitogenic phenotype. In addition, we find that phosphorylation of the epidermal growth factor receptor and of 80-kDa and 22-kDa proteins, as well as the tyrosine phosphorylation of a 42-kDa protein, all proceed normally in the nonmitogenic variant, even though these phosphorylations must depend on the activation of different kinases. Thus, all these early phosphorylation reactions are intact in the 3T3-TNR9 cells. Although these phosphorylations may be necessary, they clearly are insufficient to trigger mitogenesis.

Animals↗
PubMed1984

Transposon Tn1 intra-molecular transposition.

A system for the direct selection of intra- and inter-molecular transposition events has been used to show that intra-molecular transposition of Tn1 generates deletions and inversions and requires the tnpA but not the tnpR gene product, as predicted by current models of transposition. Intra-molecular Tn1 transposition is much less limited by 'transposition immunity' than inter-molecular transposition, and occurs at frequencies comparable to those for inter-molecular transposition. The selection system, which uses the bacteriophage lambda cI- PR region as a target can be used to select, quantify, and characterize any spontaneous or induced mutations.

Bacteriophage lambda↗
PubMed1983

A tumor promoter stimulates phosphorylation on tyrosine.

The tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate is mitogenic for normal chicken embryo fibroblasts and also causes these cells to express transiently many properties of cells transformed by Rous sarcoma virus. Since some mitogenic hormones stimulate a tyrosine-specific protein kinase activity, and since the transforming protein of RSV is a tyrosine-specific protein kinase, we have examined whether TPA also stimulates protein phosphorylation on tyrosine. We report here that TPA treatment of normal cells resulted in a very rapid phosphorylation on tyrosine of a protein peak of Mr 40 to 43 kilodaltons. Thus, a similar biochemical activity (tyrosine phosphorylation) is associated with the action of polypeptide mitogenic hormones, Rous sarcoma virus and a tumor promoter. In addition, TPA treatment resulted in rapid changes in phosphorylation of proteins on serine and threonine.

Animals↗
PubMed1983

Absence of deleterious effects of chronic microwave radiation on the eyes of rhesus monkeys.

Microwave irradiation of rhesus monkeys' eyes at 9.31 and 2.45 GHz and at an average power density of 150 mW per centimeter square is reported. Irradiation, beginning in 1976, of 17 monkeys (Macaca mulatta) was accomplished without restraint or anesthesia by training the monkeys to irradiate themselves. To data microwave radiation of these monkeys has not resulted in deleterious ocular effects.

Animals↗
PubMed1983

Cryptosporidiosis in hospital patients with gastroenteritis.

Among 884 hospital patients with gastroenteritis, 36 (4.1%) were excreting Cryptosporidium oocysts in their stools; only 5 of the 36 patients were also excreting other enteropathogens, while none of 320 hospital patients without gastroenteritis were excreting Cryptosporidium oocysts. Children were more commonly infected with Cryptosporidium (4.8%) than were adults (1.6%). The prevalence of infection was higher (7%) during the summer period of February-May 1981 than in the remainder of the observation period to the beginning of June 1982 (1.9%). The most common clinical manifestation of gastroenteritis in Cryptosporidium-infected patients was diarrhea, lasting from 3 to over 14 days, accompanied by vomiting, anorexia, and abdominal pain. The results show that a small proportion of patients with gastroenteritis are infected with Cryptosporidium, and the importance of the infection needs to be examined.

Adolescent↗
PubMed1979

The toxicity of hexachloroethane in laboratory animals.

Studies were conducted to assess hazards to personnel exposed to hexachloroethane (HCE) in an industrial setting. Acute testing in laboratory animals indicated HCE was moderately toxic orally and could produce reversible eye irritation and mild skin irritation. Percutaneous absorption appeared to have no practical significance. The subchronic vapor inhalation toxicity was determined in rats, guinea pigs, Japanese quail and dogs in a 6-week test, monitoring pulmonary function changes, teratogenicity and operant behavioral changes in addition to clinical chemistry, hematology and histopathology. Concentrations of 260 ppm HCE vapor caused severe systemic effects in dogs, moderate effects in guinea pigs and rats and almost no responses in quail. No differences were found between exposed and control animals at 3 months after termination of these exposures. Minimal toxic effects were found following similar 6-week tests at levels of 48 ppm with no detectable changes at 15 ppm of HCE.

Abnormalities, Drug-Induced↗
PubMed1978

Structure of yeast phenylalanine-tRNA genes: an intervening DNA segment within the region coding for the tRNA.

Sixteen bacterial clones containing sequences complementary to yeast PhetRNA were isolated from a collection of hybrid plasmids containing BamHI restriction endonuclease-generated yeast DNA fragments inserted in the plasmid vector pBR315. Ten of these clones contained hybrid plasmids with distinct BamHI fragments. The sequence of the Phe-tRNA structural genes and adjacent regions of three of these clones is reported here. In the region flanking the tRNA gene, the sequence of two of the cloned DNAs is similar; the sequence of the third varies considerably. All three of the tRNA genes are bordered by A,T-rich regions. In particular, near the region coding for the 3' end of the tRNA there is a long sequence of As in the coding strand. This is reminiscent of the region of termination of transcription of the yeast 5S rRNA gene. The sequences coding for the Phe-tRNA contain an additional segment of 18 or 19 base pairs (depending upon the clone) not predicted by the yeast Phe-tRNA sequence. These intervening segments are nearly identical in the three clones and are located within the structural gene, two base pairs from the nucleotides coding for the tRNA anticodon.

Anticodon↗
PubMed1978

"Paradoxical" reduction in postexercise ejection time and increased transthoracic impedance.

Despite decreasing heart rate, left ventricular ejection time (LVET) transiently falls immediately following bicycle exercise. In seven normal, untrained subjects LVET decreases at 15 s postexercise corresponded (r = 0.78) with an increase in transthoracic electrical impedance (Z) consistent with decreased venous return to the thorax. Because the determinants of LVET are stroke volume (SV) and ejection rate, the deltaZ implies that decreased SV contributed to the "paradoxical" fall in LVET.

Adult↗
PubMed1976

Duovirus infection as a cause of infantile gastro-enteritis in Port Moresby.

A preliminary study of nine children under five years of age admitted to Port Moresby General Hospital with acute gastro-enteritis showed that five (56%) were excreting duovirus in their stools as shown by electron microscopy. Duovirus was not demonstrated in the stools of any of eight children with gastro-enteritis seen at Kainantu Health Centre.

Feces↗