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Biomedical subjects

C Andres

Publications and source records attributed to C Andres.

36 records · Page 2Linked to original sources
PubMed1994

Serum lipoprotein levels and plasma concentrations of insulin, intact and 32, 33 split proinsulin in normoglycaemic relatives of patients with type 2 diabetes.

Type 2 diabetes is associated with abnormal lipoprotein levels and altered plasma concentrations of insulin, intact and 32, 33 split proinsulin. To investigate whether these are early features of the disease, we studied 36 normoglycaemic first-degree relatives of patients with Type 2 diabetes (13 European, 15 of Asian (Indian-subcontinent), and 8 of Afro-Caribbean origin) and 36 control subjects with no family history of diabetes. Relatives and controls were matched for age (mean +/- S.E. 33 +/- 2 vs 34 +/- 2 years), body mass index (23.7 +/- 0.5 vs 23.7 +/- 0.6 kg m-2), sex (17 M, 19 F) and ethnic origin. After an overnight fast, blood was sampled for measurement of serum lipids, plasma glucose and insulin, intact and 32, 33 split proinsulin by specific immunoradiometric assays. Relatives and controls had similar fasting concentrations of glucose (5.0 +/- 0.1 vs 4.9 +/- 0.1 mmol l-1), total cholesterol (4.51 +/- 0.13 vs 4.54 +/- 0.17 mmol l-1), HDL-cholesterol (1.21 +/- 0.06 vs 1.10 +/- 0.05 mmol l-1), LDL-cholesterol (2.84 +/- 0.14 vs 2.96 +/- 0.14 mmol l-1) and triglyceride (median (range) 0.78 (0.44-2.45) vs 0.83 (0.41-4.03) mmol l-1). Fasting levels of insulin (50.4 (18.9-174.0) vs 51.6 (10.0-118.0) pmol l-1, intact proinsulin (2.8 (0.1-15.0) vs 2.1 (0.6-6.4) pmol l-1 and 32, 33 split proinsulin (2.0(0-23.7) vs 1.6 (0.3-6.0) pmol l-1) were not significantly different between relatives and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Fetal proinsulin and birth weight.

In both diabetic and non-diabetic pregnancies fetal insulin is an important anabolic hormone. Fetal hyperinsulinaemia is associated with accelerated fetal growth and increased birth weight. Insulin and C-peptide concentrations in both umbilical cord and amniotic fluid reflect fetal beta-cell secretion and are correlated with birth weight. In the present study umbilical venous proinsulin and insulin concentrations were measured in 54 term infants born to women with and without mild disturbances of glucose tolerance. Umbilical venous cord proinsulin, assayed using a highly specific immunoradiometric assay, was independently correlated with infant birth weight (Rho = 0.53, p < 0.0001) and birth percentile (Rho = 0.65, p < 0.0001). The correlation between birth weight and birth percentile weight with umbilical venous insulin, measured using a non-specific insulin assay, was lost following correction for the influence of proinsulin. Umbilical venous cord proinsulin appears to be a good indicator of fetal beta-cell activity, and in this study, a superior marker to insulin assayed using a non-specific insulin radioimmunoassay. The longer half-life of proinsulin compared with insulin may contribute to proinsulin being a more robust marker of overall fetal beta-cell activity than insulin.

Adult↗
PubMed1992

A unique hydrophobic domain of rat brain globular acetylcholinesterase for binding to cell membranes.

Both salt-soluble and detergent-soluble rat brain globular acetylcholinesterases (SS- and DS- AChE EC 3.1.1.7) are amphiphiles, as shown by detergent dependency of enzymatic activity and binding to liposomes. Proteinase K and papain treatment transformed SS-AChE and DS-AChE into forms that, in absence of detergent, no longer aggregated nor bound to liposomes. In contrast, phosphatidylinositol-specific phospholipase C had no effect on these properties. Labeling DS-AChE with 3-(trifluoromethyl)-3-(m-(125I)-iodophenyl) diazirine ([125I]TID) revealed, by polyacrylamide gel electrophoresis under reducing conditions, one single band of 69 kD apparent molecular mass. The same pattern was previously obtained with Bolton and Hunter reagent-labeled enzyme. Proteinase K treatment transformed the 11 S [125I]TID labeled AChE into a 4 S form which no longer showed 125I-radioactivity and was unable to bind to liposomes. These results are compatible with the existence of a hydrophobic segment present both on salt-soluble and detergent-soluble 11 S AChE as well as on the minor forms 4 S and 7 S. This segment is not linked to the catalytic subunits by disulfide bounds in contrast to the 20 kD non-catalytic subunit described by Inestrosa et al.

Acetylcholinesterase↗
PubMed1991

R-bodies in Pseudomonas aeruginosa strain 44T1.

For the first time R-bodies are described in a new strain 44T1 of Pseudomonas aeruginosa. Its size was measured as being 0.22 to 0.37 microns of width per 0.27 to 0.41 microns of length and 5 to 9 spiral turns about 16 nm. These structures are similar to previously observed in bacteria and are related with physiological state of bacteria in minimal conditions of growth.

Bacterial Proteins↗
PubMed1991

Separation in a single step by affinity chromatography of cholinesterases differing in subunit number.

We describe an affinity chromatography method in which dimethylaminoethylbenzoic acid-Sepharose 4B is used, making it possible to separate in one step the molecular forms of globular acetylcholinesterase (AChE, EC 3.1.1.7) or butyrylcholinesterase (ChE, EC 3.1.1.8). A crude extract containing these enzymes was deposited onto the chromatography gel, washed, and eluted by a linear gradient of tetramethylammonium chloride (0-0.3 M). With rat brain AChE, two well-separated peaks were eluted in the presence of 1% Triton X-100; the first peak corresponded to 4 S forms and the second to 11 S forms. This separation was very efficient for salt-soluble activity and less efficient for the detergent-soluble AChE. In this case, the 4 S peak represented only 6.5% of total detergent-soluble activity and was cross-contaminated by the 11 S form. Rat serum ChE was efficiently separated into two peaks of 7 S and 11 S. This method could potentially be adapted to separate other multimeric proteins with varying numbers of affinity sites.

Acetylcholinesterase↗
PubMed1990

Are soluble and membrane-bound rat brain acetylcholinesterase different?

Salt-soluble and detergent-soluble acetylcholinesterases (AChE) from adult rat brain were purified to homogeneity and studied with the aim to establish the differences existing between these two forms. It was found that the enzymatic activities of the purified salt-soluble AChE as well as the detergent-soluble AChE were dependent on the Triton X-100 concentration. Moreover, the interaction of salt-soluble AChE with liposomes suggests amphiphilic behaviour of this enzyme. Serum cholinesterase (ChE) did not bind to liposomes but its activity was also detergent-dependent. Detergent-soluble AChE remained in solution below critical micellar concentrations of Triton X-100. SDS polyacrylamide gel electrophoresis of purified, Biobeads-treated and iodinated detergent-soluble 11 S AChE showed, under non reducing conditions, bands of 69 kD, 130 kD and greater than 250 kD corresponding, respectively, to monomers, dimers and probably tetramers of the same polypeptide chain. Under reducing conditions, only a 69 kD band was detected. It is proposed that an amphiphilic environment stabilizes the salt-soluble forms of AChE in the brain in vivo and that detergent-soluble Biobeads-treated 11 S AChE possess hydrophobic domain(s) different from the 20 kD peptide already described.

Acetylcholinesterase↗
PubMed1985

[Changes in iodine metabolism in patients with burns treated topically with PVP-iodine].

Under exposure treatment of 33 burn patients with povidone-iodine (polyvinylpyrrolidon-iodine) preparations (Betaisodona ointment and solution) massive absorption of the iodine by the body and temporary changes in the thyroid hormones (T3 and T4 lowered, TSH raised) were found. No other clinical or laboratory-chemical side effects were observed in the patients. TRH stimulation test was carried out on 18 patients 3-6 months after ceasing povidone-iodine application. The results showed normoreaction of the hypothalamus-pituitary regulation. Povidone-iodine topical treatment of the burn patients involves them in substantial exposure to iodine, but offers no additional risk to the patients.

Administration, Topical↗
PubMed1985

Investigations on fly-ash and soil samples in the environment of a coal-fired power plant.

In the main wind direction of a coal-fired power plant dust and soil samples have been collected to analyse the content of fly-ash coming from the power plant. The fly-ash particles are spherical and contain the natural radionuclides mainly Ra-226, Pb-210, Po-210 and K-40 in a higher concentration when compared with the original coal. The investigation of soil samples results in increased Pb-210 and Po-210 concentrations when compared with the natural environment. By presence of spherical particles in dust and soil samples the power plant can be identified as the emitter.

Air Pollutants↗
PubMed1984

[Iodine resorption from PVP-iodine preparations after their use in humans].

The absorption of iodine from iodine-containing PVP preparations and the possibility of iodide being split off from the organic compound were tested in subjects with normal thyroid function after they had used PVP-iodine as mouth-antiseptic (15 subjects), vaginal gel (20 subjects) or liquid soap (20 subjects). Serum I-, T3, T4, TSH and urinary iodide excretion were measured, as an index of thyroid function, before and after the PVP application. Increase in iodine supply was up to 2 mg daily in the test subjects. The overwhelming proportion of the absorbed iodine (greater than 75%) was as organically bound iodine. In none of the subjects was there evidence of developing hyper- or hypothyroidism as a result of the additional iodine supply. Approximate values for the biological half-life and the distribution volume of total iodine in the body were also obtained.

Absorption↗
PubMed1979

Purine nucleoside phosphorylase deficiency: biochemical properties and heterogeneity in two families.

The biochemical features of two families with purine nucleoside phosphorylase deficiency are compared. Laboratory studies and an evaluation of kinetic and physical properties of erythrocyte purine nucleoside phosphorylase give evidence that a) the degree of abnormality in uric acid and nucleoside concentrations in plasma and urine reflect the severity of the enzymatic deficiency and b) structural alterations of the mutant enzymes result from structural gene mutations and demonstrate genetic heterogeneity in the disease purine nucleoside phosphorylase deficiency.

Child↗
PubMed1973

Hypocomplementemia of membranoproliferative nephritis. Dependence of the nephritic factor reaction on properdin factor B.

Membranoproliferative nephritis in children is frequently associated with a hypocomplementemia produced at least in part by C3 breakdown mediated by a circulating anticomplementary factor known as C3 nephritic factor (C3NeF). C3 breakdown by this factor in vitro requires the presence of a pseudoglobulin cofactor and magnesium. The present study provides evidence that properdin factor B (C3 proactivator) is activated in the nephritic factor reaction and is the direct mediator of C3 breakdown by C3NeF. Depletion of factor B from mixtures of normal human serum (NHS) and plasma from a patient with membranoproliferative nephritis (MPP), either by heating or by immune equivalence absorption, blocks C3 breakdown by C3NeF. Addition of purified factor B to these mixtures restores the anticomplementary effect. When purified factor B is added to mixtures of MPP and purified C3, breakdown also occurs. Associated with the C3 breakdown is a change in the electrophoretic mobility of factor B from the beta to the gamma position, a shift which has been associated with cleavage activation of the molecule. Further, serum factor B levels are often low in patients with membranoproliferative nephritis and bear a rough inverse correlation with C3NeF levels. It thus appears that factor B is the previously described heat-labile C3NeF cofactor. Whether the C3NeF reaction proceeds via a pathway comparable to that activated by the cobra venom factor or via that activated by zymosan or inulin cannot be determined from the present data.

Absorption↗
PubMedDate not supplied

Transgenic acetylcholinesterase induces enlargement of murine neuromuscular junctions but leaves spinal cord synapses intact.

Acetylcholinesterase (AChE) produced by spinal cord motoneurons accumulates within axo-dendritic spinal cord synapses. It is also secreted from motoneuron cell bodies, through their axons, into the region of neuromuscular junctions, where it terminates cholinergic neurotransmission. Here we show that transgenic mice expressing human AChE in their spinal cord motoneurons display primarily normal axo-dendritic spinal cord cholinergic synapses in spite of the clear excess of transgenic over host AChE within these synapses. This is in contrast to our recent observation that a modest excess of AChE drastically affects the structure and long-term functioning of neuromuscular junctions in these mice although they express human AChE in their spinal cord, but not muscle. Enlarged muscle endplates with either exaggerated or drastically shortened post-synaptic folds then lead to a progressive neuromotor decline and massive amyotrophy (Andres et al., 1997). These findings demonstrate that excess neuronal AChE may cause distinct effects on spinal cord and neuromuscular synapses and attribute the late-onset neuromotor deterioration observed in AChE transgenic mice to neuromuscular junction abnormalities.

Acetylcholinesterase↗
PubMedDate not supplied

Increased maternal fasting proinsulin as a predictor of insulin requirement in women with gestational diabetes.

Circulating proinsulin was assessed during a 75g OGTT in 55 pregnant women who fulfilled WHO criteria for impaired glucose tolerance before the 32nd gestational week. Proinsulin was assayed retrospectively using a two-site immunoradiometric assay and immunoreactive insulin by radioimmunoassay. Of the 55 women, 19 required insulin treatment in addition to diet later in pregnancy. Fasting proinsulin concentrations were significantly higher in the 19 women who later required insulin treatment compared with the 36 women treated with diet alone (3.4 +/- 0.7 vs 1.8 +/- 0.2 pmol l-1, p < 0.005). There was no difference between the treatment groups of 60 and 120 min proinsulin values during the OGTT. Fasting plasma glucose and immunoreactive insulin were similar in the insulin-treated and diet-treated women and remained similar during the OGTT. No women within the insulin-treated group had a fasting plasma proinsulin value < 1.1 pmol l-1 in contrast with 12 women in the diet-treated group (p = 0.0123). Ten of the 19 insulin-treated women had a fasting plasma proinsulin > 2.5 pmol l-1 compared with 8 of the 36 diet-treated women (p = 0.0346). Fasting proinsulin values early in pregnancy have prognostic implications in women with gestational diabetes.

Adult↗
PubMedDate not supplied

[Measuring physical disability and psychosocial consequences of chronic backache].

Low back-pain is one of the most frequent symptoms and its chronicity causes considerable socioeconomic costs in many countries. To evaluate the efficiency of therapeutic approaches in low back-pain we need reliable information concerning patient health status in its physical and psychosocial dimensions. After adapting the MOPO-scales, which have proven a reliable instrument in other rheumatic diseases, to special requirements in low back-pain, we assessed patient outcome using eight scales and calculating a summated health score. Statistical analysis yielded evidence our instrument to be reliable, valid, sensitive and practicable in assessing patient outcome in low back-pain.

Activities of Daily Living↗