Search PubMed⌕ Search

Biomedical subjects

A Green

Publications and source records attributed to A Green.

At least 541 records · Page 30Linked to original sources
PubMed1987

Use of permanent hair dyes and risk of breast cancer.

Aromatic amines contained in permanent hair dyes can be absorbed percutaneously and are mutagenic and carcinogenic in some laboratory studies. Concern has been raised that use of these dyes may increase the risk of human cancers. Therefore, the present study examined the relationship between permanent hair dye use and incidence of breast cancer among 118,404 U.S. women aged 30-55 years who were followed prospectively for 6 years. Among women who had ever used permanent hair dyes, 353 developed breast cancer during 246,848 person-years of follow-up, while 505 cases occurred during 397,460 person-years among never users (age-adjusted rate ratio = 1.1; 95% confidence interval = 0.9-1.2). Identical rate ratios were observed when women who had ever used hair dyes were subdivided into current and past users. Adjustment for known determinants of breast cancer in multivariate models did not alter these relationships. The risk of breast cancer did not increase with more frequent use, longer duration of use, or interval since first use. On the basis of these data and previous findings, it appears unlikely that the use of permanent hair dyes causes any important increase in risk of breast cancer.

Adult↗
PubMed1987

A combined segregation and linkage analysis of insulin-dependent diabetes mellitus.

In an effort to clarify the mode of inheritance of insulin-dependent diabetes mellitus (IDDM), a total of 230 nuclear families with pointers were analyzed using the computer program COMBIN. Each family was ascertained without deliberate selection for multiplex families, and most families were completely typed for HLA-B, HLA-DR, and properdin factor B (Bf). There were 186 families with normal parents, 44 families with one affected parent, and no families with two affected parents. The computer program COMBIN evaluates evidence for a major locus of disease susceptibility, linkage of the major locus to a known genetic marker locus, linkage disequilibrium between the marker haplotypes and disease susceptibility, pleiotropic effects, and presence of an unlinked modifier. The parameters of COMBIN are T, Q, and D, representing the displacement, gene frequency of the IDDM allele, and dominance, respectively, of the major locus--and TM, QM, and DM being the analogous parameters of the modifier. In addition, the recombination fraction, theta, between the IDDM locus and HLA as well as the coupling frequencies are estimated. Finally, COMBIN simultaneously performs segregation and linkage analysis, with the optimal model being adjusted by the fit to the haplotype sharing distribution of IDDM. The results of these analyses indicated that the best-fitting genetic model of diabetic susceptibility appears to be a single major locus with near recessivity on a scale of standardized genetic liability, with gene frequency of the IDDM susceptibility allele of approximately 14%. In addition, the recombination fraction between the major locus and HLA is zero in all models; that is, for the B-BF-DR haplotype, the IDDM locus is tightly linked, probably (according to data from previous studies) to HLA-DR. Information determined by magnitude of coupling frequencies indicated that there is significant positive linkage disequilibrium with the haplotypes B8-BfS-DR4 and B15-BfS-DR4, significant negative linkage disequilibrium with B7-BfS-DR2, and intermediate disequilibrium for B8-BfS-DR3, B18-BfF1-DR3, and B40-BfS-DR4. Significant evidence in favor of an unlinked (to HLA) modifier (either single major locus or polygenes) could not be demonstrated. In conclusion, genetic susceptibility to IDDM appears to be most consistent with a single major locus with near recessivity that is tightly linked to HLA.

Chromosome Mapping↗
PubMed1986

Photochemical cross-linking of 125I-hydroxyphenylisopropyl adenosine to the A1 adenosine receptor of rat adipocytes.

Rat adipocyte plasma membranes were incubated with the A1 adenosine receptor agonist, 125I-hydroxyphenylisopropyl adenosine (1 nM) and then treated with the photoactive cross-linking agent, ANB-NOS. The membranes were solubilized and analyzed by SDS-PAGE and autoradiography. A single protein, Mr approx. 38,000, was specifically labeled. Reduction with 2-mercaptoethanol did not affect the apparent Mr of the labeled protein. Labeling was inhibited by the adenosine receptor agonists, HPIA, PIA and NECA, and by the antagonist, theophylline, but was unaffected by inosine. We conclude that the A1 adenosine receptor is a single protein of Mr approx. 38,000.

Adenosine↗
PubMed1986

The insulin-like effect of sodium vanadate on adipocyte glucose transport is mediated at a post-insulin-receptor level.

Sodium vanadate has several insulin-like effects. To determine whether vanadate acts via the insulin receptor, I investigated the effect of vanadate on glucose transport (2-deoxyglucose uptake) in adipocytes that had been treated to decrease the number of insulin receptors. Trypsin (100 micrograms/ml) caused greater than 95% loss of 125I-insulin binding and rendered glucose transport resistant to both insulin and an anti-insulin-receptor antibody. However, vanadate caused an 8-fold increase in the transport rate [EC50 (concn. giving 50% of maximum effect) 0.2 mM] in both control and trypsin-treated cells, demonstrating that the insulin receptor does not have to be intact for vanadate to stimulate glucose transport. Insulin receptors were depleted by treatment of adipocytes with insulin (100 ng/ml) in the presence of Tris (which blocks receptor recycling). A 2 h treatment caused 60% loss of receptors, and a shift to the right in the dose-response curve for insulin stimulation of glucose transport (EC50 0.3 ng of insulin/ml in controls, 1.2 ng/ml in treated cells). The response to vanadate was again unaffected. Treatment with insulin for 4 h caused a 67% decrease in insulin binding and, in addition to the rightward shift in the insulin dose-response curve, a decrease in basal and maximal transport rates (which cannot be explained by decreased insulin receptor number). The EC50 of vanadate was again equal in control and treated cells, but glucose transport in the presence of a maximally effective concentration of vanadate (1 mM) was decreased. I conclude that the effect of vanadate on glucose transport is independent of the insulin receptor. Induction of a post-receptor defect (which may be a decrease in the total number of cellular glucose transporters) by prolonged exposure to insulin decreases the potency of a maximally effective concentration of vanadate. The findings demonstrate that vanadate stimulates glucose transport by an effect at a level distal to the insulin receptor.

Adipose Tissue↗
PubMed1986

Biobehavioral treatment of essential hypertension: a group outcome study.

In a group outcome and follow-up study of 77 patients with essential hypertension, significant reductions were seen in systolic and diastolic blood pressure (BP) and in hypotensive medication requirement. A multimodality biobehavioral treatment was used which included biofeedback-assisted training techniques aimed at teaching self-regulation of vasodilation in the hands and feet. Of the 54 medicated patients, 58% were able to eliminate hypotensive medication while at the same time reducing BP an average of 15/10 mm Hg. An additional 19 (35%) of the medicated patients were able to cut their medications approximately in half while reducing BP by 18/10 mm Hg. The remaining 4 (7%) medicated patients showed no improvement in either BP or medication requirement. Similar reductions in BP were seen in initially unmedicated patients. Seventy percent of the 23 unmedicated patients achieved average pressures below 140/90 mm Hg, with an additional 22% of these patients making clinically significant reductions in pressure without becoming normotensive, and with 8% unsuccessful at lowering pressures to a clinically significant extent. Follow-up data available on 61 patients over an average of 33 months indicated little regression in these results with 51% of the total patient sample remaining well-controlled off medication, an additional 41% partially controlled, and 8% unsuccessful in lowering either medications and/or blood pressures to a clinically significant extent.

Adult↗
PubMed1986

Methodological issues in the use of the concurrent activities paradigm.

This paper presents a critical analysis of one type of dual-task procedure, the lateralized concurrent activities paradigm. Extrinsic and intrinsic factors that may influence the interpretation of results obtained with this paradigm are isolated and methodological refinements in experimental design and analysis are suggested.

Age Factors↗
PubMed1986

A time sharing cross-sectional study of monolinguals and bilinguals at different levels of second language acquisition.

Several methodological factors associated with the concurrent activities (finger-tapping) paradigm were considered in a cross-sectional study investigating cerebral patterns of asymmetry in three groups of English-speaking non-Hispanic dextral males at three levels of second language (Spanish) acquisition and one control group of monolinguals. Results revealed the fluent bilinguals to be bilateral and significantly different from other groups for native language tasks in English. Moreover, a priori contrasts indicate that greater right- than left-hand disruption in concurrent tapping may be typical of monolinguals, but can be influenced by other factors. Monolingual reliability test-retest correlations were .77 and .47.

Adult↗
PubMed1986

Amino acid profiles in early diabetic and non-diabetic pregnancy.

Plasma amino acid concentrations were measured in six insulin-dependent diabetic women and seven non-diabetic women in early pregnancy while fasting and one hour after a standard meal. Fasting plasma levels of total amino acids and individual amino acids were similar in the two groups, excepting isoleucine, which was raised in the diabetics. One hour post-prandially total amino acid concentrations were similar in the two groups; however, mean concentrations of total branched chain amino acids and mean concentration of the individual amino acids, serine, valine, isoleucine, leucine and tyrosine were elevated in the diabetics. Amino acids are important in early islet development and in insulin secretion from fetal pancreas in vitro. The elevated post-prandial amino acid levels found in pregnant diabetics in early pregnancy may contribute to fetal islet hypertrophy and hyperinsulinaemia.

Adult↗
PubMed1986

Erythrocyte transketolase activity in patients with chronic renal disease.

B1 vitamin deficiency was studied by the erythrocyte enzyme activation test in patients with chronic uraemia. Transketolase activity was measured in the erythrocyte haemolysates of 14 patients with chronic uraemia and in 16 healthy controls in the presence of TPP and following TPP saturation. The magnitude of activity increases as a result of TPP saturation which is probably indicative of an insignificant thiamine deficiency in patients with chronic uraemia.

Chronic Disease↗
PubMed1985

Bone marrow necrosis in children with malignant disease.

The authors reviewed the case records of 1419 children with acute leukemia and other types of malignant disease involving the bone marrow to define the clinical and laboratory features associated with marrow necrosis as well as the prognostic significance of this complication. Only seven patients were found to have this abnormality: four with newly diagnosed acute lymphoblastic leukemia (ALL), one with relapsed ALL, and two with disseminated neuroblastoma. All patients presented with severe bone pain, bone tenderness, and fever. Levels of serum lactic dehydrogenase were uniformly increased, being especially high in patients with ALL. There was no evidence of severe infection or disseminated intravascular coagulation, complications that have been causally related to marrow necrosis. Four of the five children with ALL remain in complete remission for 10+ to 48+ months. Both patients with neuroblastoma are off therapy, in remission, for 9+ to 15+ months. In contrast to earlier reports, bone marrow necrosis does not appear to confer a poor prognosis in children with malignancy.

Bone Marrow↗
PubMed1985

Neonatal screening for congenital hypothyroidism by measurement of plasma thyroxine and thyroid stimulating hormone concentrations.

Neonatal screening for congenital hypothyroidism was introduced in the City of Birmingham in 1980 by measuring concentrations of both thyroid stimulating hormone and thyroxine in plasma. Over two years 30 108 babies were tested. Thirty one babies were recalled because of thyroid stimulating hormone concentrations greater than 40 mU/l, of whom 12 were treated with replacement thyroxine. Six babies were found to have low thyroxine concentrations because of reduced thyroxine binding globulin and five raised thyroxine values because of increased thyroxine binding globulin. As a result of this study screening was continued with measurement of thyroid stimulating hormone only as the primary test for congenital hypothyroidism, the thyroxine value being measured only when the concentration of thyroid stimulating hormone exceeded 20 mU/l.

Congenital Hypothyroidism↗
PubMed1985

Erythrocyte zinc protoporphyrin determination for screening for lead exposure.

Free erythrocyte protoporphyrin (FEP), erythrocyte zinc protoporphyrin (EZP) and blood lead concentrations were measured in 150 male subjects, 110 of whom were employed in industries where lead exposure was possible. Eighty-seven per cent of these 110 workers had blood lead levels above the maximum safe level of 40 micrograms/dl, which suggests that the factory control of lead toxicity is inadequate. The AVIV dedicated front-face fluorometer (AVIV instruments, New Jersey, USA), which measures EZP, was evaluated as a simple, rapid method of screening for lead accumulation. EZP concentrations agreed well with conventional estimations of FEP (r = 0,987, P less than 0,0001), and both correlated well with the blood lead concentration (r = 0,558, P less than 0,0001 for EZP; r = 0,633, P less than 0,0001 for FEP). The specificity of the EZP level as a screening test was found to be high (98%) and the sensitivity moderately good (83%). In view of the ease and speed of operation of this portable fluorometer, it should prove useful as an aid to the detection of early lead intoxication.

Environmental Exposure↗