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Biomedical subjects

K May

Publications and source records attributed to K May.

At least 55 records · Page 3Linked to original sources

ELISA measurement of LDL receptors.

An enzyme-linked immunosorbent assay was developed for measurement of low density lipoprotein (LDL) receptors. A monospecific polyclonal antibody to LDL receptor purified from rat liver that reacted with rat, mouse, canine, and human LDL receptor was used. With this assay, LDL receptors could be measured on 2-4 x 10(5) adherent cells and 1.0 x 10(5) cells in suspension, although results were more variable with cell suspensions. Membranes from a variety of receptor-rich and receptor-poor tissues could be assayed directly after adherence of the membranes to the ELISA plate by an overnight incubation. In some instances, the quality of the assay was improved by first solubilizing the membranes. The sensitivity of the assay is such that between 0.15 and 2 micrograms of membrane protein is required. This could be obtained from leukocytes in a modest (20-30 ml) quantity of human blood. The assay was used to demonstrate the rapid down-regulation of LDL receptors in human mononuclear leukocytes in response to a cholesterol-containing meal. Overall, the results support the use of ELISA technology to measure LDL receptors, particularly for physiologic studies.

Adult↗

A new venture in health care.

The setting up four new well-woman drop in centres in Bristol is described, together with a preliminary evaluation of take-up and the team approach to preventive health care.

Adult↗

Mechanisms responsible for inhibition of vein-graft arteriosclerosis by fish oil.

Favorable changes in lipoproteins, inhibition of platelet aggregation, reduction of serum thromboxane (TX), altered plasma-membrane fluidity, and reduced production of growth factors (mitogens) have all been implicated as possibly being involved in the inhibition of arteriosclerosis by fish oil (FO), which is rich in omega 3 fatty acids; however, causal relations are mostly lacking. Several putative mechanisms responsible for the salutary effects of FO were investigated in a canine model of accelerated vein-graft arteriosclerosis. Venoarterial autografts (N = 192) were implanted in 48 hypercholesterolemic dogs divided into six groups: group A, control; B, FO (as MaxEPA, 200 mg/kg/day eicosapentaenoic acid); C, aspirin (ASA, 50 mg/kg/day); D, TX synthetase inhibitor (TXSI [CGS-12970], 10 mg/kg/day); E, FO + ASA; and F, FO + TXSI. At sacrifice 3 months later, there was no significant difference in plasma lipoproteins, hepatic low density lipoprotein-receptor concentration, red blood cell fragility, bleeding time, or platelet count compared with controls; the decrease in platelet aggregation (30 +/- 5% [mean +/- SEM]) was similar in all treatment groups. Arterialized vein-graft intimal thickening was significantly inhibited by FO (with or without ASA), while ASA alone was ineffective. Conversely, serum TX was significantly lower only in the ASA and FO + ASA groups. Serum mitogenic activity was higher at 3 months in the control group versus all treatment groups. Compared with baseline values, serum mitogenic activity rose significantly over time in the control and the TXSI groups, and an increase or rising trend was present in all other treatment groups except for the FO-treated animals. Thus, the salutary biologic effect of FO in this hypercholesterolemic model of arterialized vein grafts may have been more related to in vivo inhibition of platelet-mitogen growth factor release than to changes in lipoproteins, low density lipoprotein receptors, platelet function, or eicosanoid metabolism. These observations underscore the need for further studies to clarify the interactions between FO (omega 3 fatty acids) and paracrine cellular mitogenic factors in the context of atherosclerosis prevention.

Animals↗

Further exploration of maternal and paternal fetal attachment.

Fetal attachment of four groups of expectant parents were studied during the 24th to 34th weeks of pregnancy: 153 high-risk women hospitalized for a complication, 75 high-risk women's mates, 218 low-risk women, and 147 low-risk women's mates. No differences in fetal attachment scores were observed between high- or low-risk women or their mates; women scored significantly higher than their mates. Very little variance (7% to 14%) in fetal attachment was explained by the test of causal models except for high-risk women's mates for whom 31% of the variance was explained.

Anxiety↗

Karyological identification of two taxa of the Anopheles balabacensis complex from Burma.

Giemsa and Hoechst staining of neuroblast chromosomes were used to identify two strains of the Anopheles balabacensis complex from Burma. The laboratory colony of Kwan-ka-thaung (KKT) strain is shown to correspond to A. dirus A, while the laboratory colony of Taikkyi (TKK) strain corresponds to A. dirus C as defined by earlier studies on material from Thailand.

Animals↗

Chemical and biological properties of a cationic Tc-tetraamine complex.

The complex of 99Tc with the ligand 1,4,8,11-tetraazaundecane (2,3,2-tet) was prepared and was compared with the similar 99Tc complexes with ethylenediamine and 1,4,8,11-tetraazacyclotetradecane. The results are all consistent with the formula [TcO2(2,3,2-tet)]+. The biological behavior was tested with 99mTc in Wistar rats. A fast clearance via the kidneys was found, and no accumulation in any other organ was observed.

Animals↗

Hypersensitivity to dietary components in young farm animals: isolation and partial purification of bovine immunoglobulin E.

An antibody of known specificity and active in long (72 hours) latent period passive cutaneous anaphylactic reactions, was isolated and partially purified from bovine serum. This antibody was not associated with immunoglobulins IgG, IgM or IgA. A rabbit antiserum raised against this antibody and used as an immunoabsorbent, successfully recovered skin sensitising antibody from bovine reaginic serum.

Animals↗

The amino acid sequence of human liver apoferritin.

The protein component of the iron storage molecule, ferritin, contains 24 subunits in form of a hollow shell known as apoferritin. The amino acid sequence has been determined for apoferritin subunits from human liver. The sequence comprises 174 amino acids giving an Mr of 19 900. It shows extensive homology with the primary structures of apoferritins from human and horse spleen and from rat liver. Sequence substitutions are discussed in relation to the known three-dimensional structure of horse spleen apoferritin. Evidence for a second minor sequence in human liver apoferritin is presented.

Amino Acid Sequence↗

Determination of functional domains in intron bI1 of yeast mitochondrial RNA by studies of mitochondrial mutations and a nuclear suppressor.

The sequence of intron 1 in the cob gene in mtDNA (bI1) of the yeast strain 777-3A has been determined. Furthermore, we have performed a systematic search for complementary sequence stretches within this intron RNA, and within the RNA of intron 5 gamma of the oxi3 gene (aI5 gamma) which shares distinctive sequences with bI1. Possible secondary structure models derived from this analysis show nearly identical core structures for bI1 and aI5 gamma RNA with conserved sequence stretches in prominent positions. These core structures are similar to those previously reported for RNAs of introns having very limited sequence homology with bI1 and aI5 gamma. In two mutants which are defective in bI1 excision from cob pre-mRNA, nucleotide sequence alterations in bI1 have been determined. One mutation (G5049) apparently affects the stability of a hybrid stretch in the proposed secondary structure of bI1 RNA whereas the other one (M1301), a deletion of one A in a run of five As, affects a sequence which is conserved in bI1 and aI5 gamma and is involved in the formation of a distinct secondary structure. Out of seven revertants of M1301, three were found to have restored the wild-type bI1 sequence AAAAA, three others had the related sequence AAAAG which is functionally indistinguishable from wild-type, whereas one revertant had a nuclear mutation which suppresses the splicing defect exerted by the mitochondrial mutation M1301. This nuclear suppressor (SUP-101) is allele specific and dominant. The possible role of the sequence affected by M1301 in terms of a recognition site for a nuclear gene product will be discussed.

Base Sequence↗