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2.
West Indian med. j ; 36(Suppl): 30, 1987.
Artigo em Inglês | MedCarib | ID: med-5999

RESUMO

Chronic nutrient inadequacy, as exemplified by marasmus and kwashiorkor provides a model for insulin-binding studies. Red cell insulin receptors were studies in infants (age range 4 to 24 months) whilst malnourished and at 3 different stages of anthropometric recovery (60-84, 85-95, and 96-110 percent weight-for-height (EWH)). Four-hour fasting blood samples (3 ml) were used. Washed red cells (concentration 0.75 - 1.5x10 Esp 9/ml) were incubated at 15§C for 180 min in the presence of a constant amount of tracer (A[14] - I[125] - insulin, 16.6 - 1680 pM, 7 different concentrations). Non-specific binding was assessed by the radioactive insulin bound in 10,000 x the physiological range of insulin concentration. From the competitive binding curve, total binding, affinity and number of receptor sites were calculated by Scatchard analysis. Specific insulin-binding was expressed as the per cent of total A[14] -I[125]-insulin added at a cell concentration of 4x10Exp9/ml. Red cell specific insulin-binding (SB) in malnutrition (rate of weight change, (RWC) - 2.05ñ1.9 (10) g/kg/d) was 4.2ñ0.8 (12) percent. This was significantly less than at all three phases of recovery (p<0.01). At 60-84 percent EWH(RWC ñ 11.7ñ0.9 (20)), SB was 8.6ñ1.2 (20) percent: at 96 -110 percent EWH (RWC ñ 0.95ñ1.1 (11)), SB was 8.8ñ1.4 (11) percent. A significantly (p<0.01) lower affinity of insulin for its receptor was shown in malnutrition, 0.9ñ0.2 (12) (Kx10Exp-8 M) than at other phases of recovery, 1.8ñ0.1 (24), 1.6ñ0.2 (20), and 1.4ñ0.4 (11) respectively. There were no significant changes in the number of receptor sites during malnutrition or during the catch-up growth phases. There was a highly significant positive correlation between rate of weight change and specific insulin-binding, (r= 0.45, p<0.0001 (67) as compared with plasma insulin concentration (r=0.33, p<0.01). Specific insulin-binding was also significantly correlated with the affinity of insulin for its receptor 9 r=0.28) p<0.05 (67)). Preliminary Results suggest that decreased protein, but not the carbohydrate or fat content of the diet, was associated with reduced insulin receptor affinity. Chronic nutritional inadequacy alters the affinity of the red cell receptor for insulin, leading to decreased binding, and this is quickly reversed early in rehabilitation. Decreased insulin-binding may be related to the carbohydrate intolerance of severe malnutrition (AU)


Assuntos
Humanos , Lactente , Distúrbios Nutricionais , Aumento de Peso , Ligação Proteica
3.
West Indian med. j ; 24(1): 46-54, Mar. 1975.
Artigo em Inglês | MedCarib | ID: med-11142

RESUMO

The effect of Lactoferrin (LF) on complement activity has been studied using the sheep red blood cell - haemolysin system. Although Lactoferrin itself is devoid of complement activity, it does affect complement action. In the absence of 2 C50 units of complement, lysis occurs, the amount observed depending on the ratio of complement to Lactoferrin used. C1 was shown to be the target for Lactoferrin action, since the inhibition of lysis produced by 500 ug of Lactoferrin, could be completely reversed by crude C1.C3, a contaminant of this crude preparation, had no such effect. Investigations to establish the specific effect of Lactoferrin on C1 indicate that Lactoferrin is a potent activator of C1, since a six-fold increase in C1 activity results when they are mixed together. These observations are consistent with the hypothesis, that Lactoferrin exerts an influence on the complement system, as a result of its capacity to activate C1. (AU)


Assuntos
Humanos , 21003 , Proteínas do Sistema Complemento , Lactoferrina/farmacologia , Lactoglobulinas/farmacologia , Complemento C1/isolamento & purificação , Complemento C3 , Depressão Química , Eritrócitos/imunologia , Cobaias/imunologia , Proteínas Hemolisinas , Ferro/metabolismo , Ligação Proteica , Ovinos/imunologia
4.
Arch Dis Child ; 49(7): 525-30, July 1974.
Artigo em Inglês | MedCarib | ID: med-13051

RESUMO

A longitudinal study of 300 infants from birth to 1 year of age was carried out in Kingston, Jamaica. Haemoglobin levels were estimated 7 times during the year and serum iron and total iron binding capacity once. Hb electrophoresis was performed. In singleton children with Hb genotype AA, AS, or AC, and of birthweight 2.5kg or over, Hb levels were low after 3 months of age. These low levels were associated with iron deficiency, which was probably due to poor iron stores at birth followed by poor iron intake or absorption. It was not possible to determine whether folic acid deficiency or protein deficiency was also important. Hb levels varied with age, socioeconomic class, birthweight, sex, and rate of weight gain. The growth and health of 4 girls with homozygous sickle cell disease is mentioned.(AU)


Assuntos
Humanos , Lactente , Masculino , Feminino , Recém-Nascido , Ferro/sangue , Hemoglobinas/análise , Ligação Proteica , Eletroforese , Genótipo , Jamaica , Peso ao Nascer , Ácido Fólico/sangue , Fatores Etários , Fatores Socioeconômicos , Fatores Sexuais , Peso Corporal , Anemia Falciforme/sangue
5.
Br J Haematol ; 25(4): 437-44, Oct. 1973.
Artigo em Inglês | MedCarib | ID: med-13321

RESUMO

The prevalence of several haemoglobin defects, including the traits for á-thalassaemia (0.8 percent), hereditary persistence of foetal haemoglobin (0.2 percent) and the abnormal delta change haemoglobin, Hb B2 (2.4 percent), were determined from the combined results of surveys conducted on adults in a suburban and a rural community. Mean Hb A2 levels of 2.6 ñ0.4 percent, 5.3 ñ0.5 percent and 2.0 ñ0.2 percent were found in 639 Hb A homozygotes, seven á-thalassaemia traits and three traits for hereditary persistence of of foetal haemoglobin (HPFH), respectively. Levels of alkali resistence haemoglobin (A.R.Hb) ranged from 0.6 to 7.3 percent in the thalassaemia traits and were 21.0, 19.0 and 16.0 percent in the three HPFH traits; the remaining 770 subjects in whom A.R.Hb was measured had a mean value of 0.6 ñ0.6 percent. (AU)


Assuntos
Humanos , Criança , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Masculino , Feminino , Hemoglobinopatias/epidemiologia , Fatores Etários , Doença da Hemoglobina C/epidemiologia , Hemoglobinometria , Hemoglobinas Anormais/análise , Ferro/sangue , Negro ou Afro-Americano , Ligação Proteica , Saúde da População Rural , Talassemia/epidemiologia , Jamaica
6.
Br J Nutr ; 29(March): 269-276, 1973.
Artigo em Inglês | MedCarib | ID: med-10406

RESUMO

The absorption of iron from 59Fe-labelled maize and soya-bean preparation was measured by whole-body counting in forty-two apparently healthy Jamaican infants and compared with the absorption of ferrous ascorbate. The mean absorption of Fe from maize was 4.3 percent and from soya bean baked at 300§, 9.4 percent, compared with 28.5 percent for ferrous ascorbate. In a group of children given boiled soya beans the mean absorption of Fe was 2.8 percent, and of ferrous ascorbate 16.7 percent. There was much variability between replicate tests made on the same child at intervals of 1-2 weeks. The absorption of food Fe was not increased in children who were considered to be anaemic (haemoglobin less than 100 g/l) or Fe-deficient (serum Fe less than 500 æg/l and saturation of total Fe-binding capacity less than 15 percent). The poor availability of Fe in maize meal, which is a staple food of children in Jamaica, is probably an important cause of the high prevalence of Fe-deficiency anaemia (AU)


Assuntos
Humanos , Lactente , Pré-Escolar , Zea mays , Absorção Intestinal , Ferro/metabolismo , Soja , Anemia Hipocrômica/etiologia , Anemia Hipocrômica/metabolismo , Proteínas Sanguíneas , Hematócrito , Hemoglobinometria , Ferro/sangue , Radioisótopos de Ferro , Ligação Proteica , Jamaica
7.
West Indian med. j;20(4): 271-5, Dec. 1971.
em Inglês | MedCarib | ID: med-10879

RESUMO

The binding characteristics of Thyroxine Binding Globulin(TBG) Pre-albumin (TBPA) and Transcortin in Jamaicans were found to be similar to those described elsewhere. The previously reported diminution in adrenocortical and thyroidal function associated with normal plasma cortisol and thyroxine levels cannot therefore be ascribed to an increase in the plasma protein binding of these hormones (AU)


Assuntos
Feminino , Humanos , Gravidez , Pré-Albumina/metabolismo , Ligação Proteica , Albumina Sérica/metabolismo , Proteínas de Ligação a Tiroxina/metabolismo , Transcortina/metabolismo , Jamaica
8.
Clin Chim Acta ; 30(1): 13-6, Oct. 1970.
Artigo em Inglês | MedCarib | ID: med-14761

RESUMO

On heating human serum with As2O3 in the presence of methanol, the level of aldehyde is increased. The increase, expressed as a percentage of the total aldehyde content, is referred to as the bound aldehyde. In the sera of patients with early malignancy, the value of bound aldehyde is found to be significantly lower than that of normal sera, but as metastases occur, it rises above the normal value. In the sera of patients with malignancy, but who responded to treatment, the value for bound aldehyde is similar to that found in the sera of patients with non-malignant disease (AU)


Assuntos
Humanos , Aldeídos/sangue , Arsenicais/farmacologia , Métodos , Neoplasias/sangue , Ligação Proteica
9.
Biochem Biophys Res Commun ; 40(6): 1507-13, Sept. 30, 1970.
Artigo em Inglês | MedCarib | ID: med-9248

RESUMO

Previous findings in the literature that rhein inhibits DPNH-linked mitochondrial oxidations by acting in the DPNH dehydrogenase region of the respiratory chain have been confirmed and extended. In the micromolar range rhein inhibits DPNH oxidase and DPNH-ferricyanide activities and the energy-linked reduction of DPNH by succinate in membrane preparations from heart, as wellas the DPNH dehydrogenase and transhydrogenase activities of the soluble, purified enzyme. The inhibition of the activities of the soluble enzyme are purely competitive with respect to substrate. These facts localize the primary inhibition site of rhein between substrate and FMN. In heart ETP a second noncompetitive inhibition is also present but is detectable only at very low (<10æM) rhein concentrations. Rhein also inhibits DPNH dehydrogenase in Candida utilis mitochondria and the purified enzyme from liver. On conversion of the heart enzyme to the low molecule weight DPNH-cytochrome reductase the typical effect of rhein disappears and is replaced by a slight stimulation or inhibition, depending on the electron acceptor used, showing that the substrate binding site is modified in this form of the enzyme. In beef liver mitochondria DPNH oxidation may appear insensitive to rhein, probably because of the strong binding of rhein to other proteins. To a lesser extent unspecific binding of rhein and resultant interference with the inhibition of DPNH dehydrogenase is also shown by BSA and by proteins in heart ETP. Rhein also inhibits transhydrogenations in mitochondria and at higher concentrations lactate and malate dehydrogenases but has no effect on sccinate, alcohol (liver nad yeast), and glucose-6-p dehydrogenases or on Neuospora DPN-ase, glucose-6-phosphatase, and amine oxidase. (SUMMARY)


Assuntos
Humanos , Recém-Nascido , Lactente , Adulto , Antraquinonas/farmacologia , Mitocôndrias Musculares/metabolismo , Oxirredutases/antagonistas & inibidores , Candida/enzimologia , Citocromos , Depressão Química , Transporte de Elétrons , Fibroblastos/citologia , Glucose-6-Fosfatase/antagonistas & inibidores , Glucosefosfato Desidrogenase/antagonistas & inibidores , Cinética , Membranas/enzimologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/enzimologia , Mitocôndrias Hepáticas , Mitocôndrias Musculares/efeitos dos fármacos , Peso Molecular , Miocárdio/citologia , Neurospora/enzimologia , N-Glicosil Hidrolases/antagonistas & inibidores , NAD/metabolismo , Oxirredução , Oxirredutases/isolamento & purificação , Oxirredutases/metabolismo , Polivinil/farmacologia , Ligação Proteica , Saccharomyces/efeitos dos fármacos , Saccharomyces/enzimologia , Soroalbumina Bovina/farmacologia , Solubilidade , Ácidos Sulfúricos/farmacologia
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