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Biomedical subjects

K R Rees

Publications and source records attributed to K R Rees.

At least 19 recordsLinked to original sources
PubMed1989

A bio-engineered rubella E1 antigen.

The major rubella envelope protein, E1, and a segment of it, comprising amino acids 207-353, have been separately expressed as fusion proteins with the IgG binding region of Staphylococcus aureus protein A in Escherichia coli. The proteins carry E1-specific antigenicity recognized by monoclonal antibodies raised against whole virus confirming that correct glycosylation is not required for antigenicity. The use of these bioengineered antigens in immunoassays for diagnosis of rubella infection and for immunization in experimental animals is described.

Amino Acid Sequence↗
PubMed1988

Diagnosis of fetal rubella infection by nucleic acid hybridization.

The efficacy of nucleic acid hybridization for the diagnosis of rubella infection in experimental and clinical materials was compared with immunoblot and virus isolation techniques. Our results showed that nucleic acid hybridization is specific and rapid but gives false-negative results when compared with conventional virus isolation in some experimental although not in clinical materials so far examined. For this reason, a failure to demonstrate rubella virus in fetal specimens by this method alone cannot yet be taken as a sole criterion for ruling out fetal rubella infection.

Abortion, Spontaneous↗
PubMed1988

Localization of the rubella E1 epitopes.

Three epitopes which react with haemagglutination inhibition and neutralizing antibodies have been located between amino acids 245-285 in the predicted amino acid sequence of rubella envelope glycoprotein E1.

Amino Acid Sequence↗
PubMed1987

The ulcerogenic and protective action of rice and rice fractions in experimental peptic ulceration.

The ulcerogenic and protective effects of various rice fractions in the diet were studied in the pylorus ligated ulcer model in the rat. Oil present in rice and particularly rice bran becomes ulcerogenic on storage and in this model results in a significant increase in the median (range) numbers of ulcers from six (one to ten) to nine (six to 15) (P less than 0.05). The ulcerogenic effect of stored rice bran oil was reversed by cysteine which significantly reduced the ulcer incidence from 100% to 60% (P less than 0.005) and the numbers of ulcers from 26 (six to 70) to one (zero to four) (P less than 0.001). Fresh rice bran significantly reduced the numbers of ulcers from six (one to ten) to one (one to four) (P less than 0.05). Similarly, unmilled rice and freshly milled newly harvested rice was also shown to be protective in this model by significantly reducing the ulcer incidence from 87.5% to 50% and 0% respectively (P values less than 0.025) and the numbers of ulcers from three (zero to 17) to one (zero to one) and zero (zero to zero) respectively (P values less than 0.001). These results could in part explain the geographical distribution of duodenal ulceration, where the incidence is high in all the rice eating areas of the world, and provide a plausible hypothesis to explain the mechanism of dietary ulcerogenesis.

Animals↗
PubMed1986

First trimester prenatal diagnosis of congenital rubella: a laboratory investigation.

Acute primary maternal infection with rubella virus during pregnancy often, but not invariably, leads to the congenital rubella syndrome. Diagnosis by detection of virus specific IgM in the mother is not always possible, and in those cases in which IgM is detected the fetus has not necessarily also been infected. A method for direct, prenatal detection of fetal infection would allow more accurate early diagnosis of congenital rubella syndrome. In this study a case of suspected preconception rubella infection that was not referred until 14 weeks after the appearance of a rash was studied to determine whether a retrospective serological diagnosis of primary rubella could be made, and whether direct evidence of fetal infection could be obtained from a chorionic villus biopsy specimen by detecting virus specific antigens or ribonucleic acid (RNA) sequences. Monoclonal antibodies and a cloned complementary deoxyribonucleic acid probe were used successfully to detect antigens to rubella virus antigens and RNA sequences in the chorionic villus biopsy specimen, which was taken at 15 weeks' gestation. This method should serve as a new approach to the diagnosis of congenital rubella syndrome in utero.

Adult↗
PubMed1986

A molecular basis of peptic ulceration due to diet.

Fresh rice oil protects against gastric ulceration in rats maintained on an impoverished diet, whereas stored oil is ulcerogenic. Rice oil contains ketoaldehydes which are ulcerogenic but their activity is prevented by the presence of antioxidants such as alpha-tocopherol, which is lost on storage. Protection may also be restored by the addition of cysteine. These results in rats in vivo can be duplicated in a rat liver microsomal system in vitro, in which malondialdehyde production is a measure of toxicity. It is proposed that the ulcerogenic activity of rice oil is the direct consequence of the stimulation of endogenous lipid peroxidation due to the lowering of the GSH content in the endoplasmic reticulum by the ketoaldehydes in stored rice oil. A similar mechanism is suggested for the ulcerogenic activity of an impoverished diet which directly lowers the tissue levels of GSH.

Aldehydes↗
PubMed1977

The synthesis of polyadenylated RNA and other RNA species in synchronised CHK cells.

Chinese hamster kidney cells have been synchronised by the double thymidine block technique. The rate of incorporation of [5-3H]uridine into the polyadenylated RNA fraction has been analysed throughout two complete cell cycles and compared with the rate of incorporation into other RNA species and the UTP pool. In contrast with other reports, we have found that synthesis of 18 S rRNA continues steadily throughout the cell cycle, as does synthesis of 5 S RNA and tRNA. In the case of the polyadenylated RNA, however, our data indicate a major peak of synthesis during S phase and a smaller peak coinciding with G1.

Cell Division↗
PubMed1976

The relationship between the turnover of UTP and RNA synthesis in cultured cells treated with aflatoxin B1.

Methods have been adapted to measure the specific activity of UTP in cells in monolayer culture. In HeLa cells labelled with [3H]uridine and treated with aflatoxin B1 there was reduced radioactivity in crude acid extracts, but the toxin did not affect the radioactive incorporation into UTP. Using cells in which the UTP was pre-labelled, the subsequent addition of aflatoxin B1 inhibited UTP incorporation into RNA. Accordingly aflatoxin B1 did not inhibit the uptake of uridine or the latter's conversion to UTP but inhibited the incorporation of UTP into RNA.

Aflatoxins↗
PubMed1975

The half-life of polyadenylated polysomal RNA from normal and transformed cells in monolayer culture.

The small genotypic differences between normal and transformed cells are insufficient to account directly for all their wide phenotypic differences, which probably in some cases at least involve alterations in control of gene expression. To ascertain whether such alterations involved changes in mRNA stability, RNA half-lives were estimated in five monolayer cell lines, including two pairs of normal cells and their transformed counterparts. The results for the polyadenylated fractions in all cases fit with those expected from a model in which the whole fraction has a single half-life, of less than one generation time. From both the transformed/untransformed cell pairs, there is evidence that a relationship exists between cell generation time and the half-life of the polyadenylated polysomal RNA fraction, which persists even through the process of transformation. Considerable alteration in the pattern of RNA stability is therefore unlikely to be obligatory in in vitro transformation.

Cell Line↗
PubMed1975

Non-histone chromosomal proteins from virus-transformed and untransformed 3T3 mouse fibroblasts.

A peak in the non-histone chromosomal protein polyacrylamide gel electrophoresis profiles has been detected which is higher in log phase 3T3 and 3T3/SV40 cells than in density-inhibited 3T3 cells. Radioactive incorporation is substantially higher into this peak in log phase 3T3 than in 3T3/SV40 and density-inhibited 3T3 cells. Reversion of 3T3/SV40 cells with dibutyryl cyclic AMP and theophylline produces increased radioactive incorporation into the peak. Electrophoresis of non-histone chromosomal proteins extracted at different stages of the cell cycle in density inhibited 3T3 cells following serum stimulation shows a cyclic variation in the amount of this peak with maximum accumulation in late G1. In contrast the height of an equivalent peak in synchronously growing 3T3/SV40 cells remains constant throughout the cell cycle. It is postulated that the protein(s) of this peak may have a regulatory role in cell growth.

Amino Acids↗