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Schizophrenia may be associated with inflammatory reactions and C-reactive protein (CRP) is a nonspecific serum protein marker for persisting inflammatory states. This study aimed to assess concentrations of high sensitivity CRP (hsCRP) in schizophrenic Arab patients and evaluate the relationships of hsCRP levels with aspects of clinical phenotypes of the disease. Two age-matched groups of subjects were studied: (1) healthy controls, HC, n =165; (2) patients with schizophrenia, SZ: n =207. Each subject was evaluated with a standard questionnaire for age at disease onset, family history, disease severity and outcome. Serum hsCRP levels were measured by immunoassay. The two groups of subjects were similar in age, ethnic composition and socioeconomic status. Those with SZ had significantly greater serum concentrations of hsCRP. There were significant associations between hsCRP and (i) age in both groups; (ii) body mass index (BMI) in HC but not in SZ. In the latter, hsCRP levels were: (a) marginally higher in women with later age of disease onset; (ii) highest with remission and with catatonic features; and (iii) lower with family history of psychosis. The study concludes that serum levels of hsCRP are increased in clinically stable Arab patients with schizophrenia and appear related to the disorder's clinical expression. It is suggested that there may be an inflammatory component to schizophrenia which is associated with aspects of its clinical phenotype.

Background: This study aimed to evaluate the blood homocysteine concentration in Arab patients with schizophrenia and assess its associations with clinical phenotypes of the disease. Subjects and methods: Two age-matched groups of subjects were studied: (1) Healthy Controls, HC, n = 165; (2) patients with schizophrenia, SZ: n = 207. Each subject was evaluated with a standard questionnaire for age at disease onset, family history, disease severity and outcome. Plasma homocysteine levels (Hcys) were measured by immunoassay and serum levels of other biochemical parameters were measured by routine Autoanalyzer techniques. Results and discussion: Group HC was heavier (body mass index, BMI) while SZ had greater waist–hip ratio (WHR) and plasma Hcys levels. In SZ, there were significant correlations between Hcys and BMI, triglycerides and HDL. Hcys levels in SZ were highest in the younger male patients. Conclusion: Schizophrenic patients have increased blood Hcys levels which correlate with components of the metabolic syndrome. Hcys levels were highest in the younger male patients and were not influenced by prognostic features of the disease.

BACKGROUND: APOE polymorphism is believed to confer susceptibility to coronary heart disease (CHD) and Alzheimer′s disease. It is well known that patterns of APOE polymorphisms differ between populations and ethnic groups, although most of the data available so far have been in whites. SUBJECT AND METHODS: We evaluated the frequencies of APOE genotypes and their relationships with serum levels of lipids, lipoproteins and apolipoproteins in two groups of Gulf Arab citizens: a control population of healthy voluntary blood donors (n=106), and a group of patients presenting to the lipid clinic for the first time with combined hyperlipidaemia (CH) (n=41). In both groups, fasting serum total cholesterol (TC), triglycerides (TG), HDL, LDL and apolipoprotein A1 and B levels were measured by routine autoanalyzer methods, and APOE genotyping was performed by validated PCR methods. The lipid and lipoprotein levels were related to the specific APOE allele frequencies. RESULTS: Allele frequencies were 5.7% for FNx01E2, 85.4% for FNx01E3, and 9.0% for FNx01E4 in the healthy blood donor group. An essentially similar pattern was seen in the patients with CH. This APOE allelic distribution conforms to patterns described in Chinese, whites and South Asians. In both the blood donor and CH groups there were no consistent links between specific APOE pattern and serum lipoproteins, as would have been predicted from APO FNx01E2 and APO FNx01E4 frequencies. CONCLUSIONS: We conclude that APOE allelic patterns in healthy Kuwaiti blood donors and a smaller group of patients with CH do not satisfactorily predict circulating blood levels of lipids and lipoproteins.

Starvation increased pyruvate dehydrogenase (PDH) kinase activity in extracts of freshly excised rat soleus 2.2-fold (from 0.6 min −1 in fed rats to 1.31 min −1 in 48-h-starved rats). In fed rats, activities were unchanged following 24 h of culture in medium 199, but increased 2.1-fold on 24 h of culture with 50 μM dibutyryl cAMP plus 1 mM n-octanoate and 1.6–1.7-fold with either agent alone. Approx. 70% of the increase in PDH kinase induced by starvation was lost following 24 h of culture in medium 199; the loss was prevented by 50 μM dibutyryl cAMP plus 1 mM n-octanoate. cAMP concentrations in fresh soleus muscle were 1 nmol/g (fed rats) and 1.6 nmol/g (starved rats). After 20–60 min of culture the fed-starved difference disappeared and [cAMP] fell to 0.4 nmol/g. Calcitonin-gene-related peptide (CGRP) increased cAMP 3-fold; the increase was maintained throughout 24 h of culture, but was readily reversed at 30 min or 24 h of culture by 60-min incubation with CGRP-free medium. Starvation of the rat (48 h) had no effect on the sensitivity of soleus towards the [cAMP]-increasing effect of CGRP. It is concluded that culture may reverse effects of starvation on PDH kinase activity by lowering cAMP and by removal from the in vivo effects of circulating free fatty acids; and that starvation and CGRP had no detectable long-term effects on the cAMP system in soleus muscle.

The plasma B-type natriuretic peptide (BNP) level is elevated in cardiac ischemia and may be useful in assessing prognosis in acute coronary syndromes (ACS). This study aimed to: (1) establish BNP levels and its determinants in a healthy Gulf Arab population and in a group of patients with acute myocardial infarction and (2) investigate associations between BNP levels and markers of myocardial damage (ejection fractions, cardiac troponin I [cTnI] levels) and inflammation (serum C-reactive protein [CRP]).We studied 2 groups of Arab subjects: (1) Healthy control (HC), 142 healthy control subjects; (2) Coronary heart disease (CHD), 257 patients with proven acute myocardial infarction within 1 day of admission. Each subject was assessed clinically, and ejection fractions (left ventricular ejection fraction [LVEF]) were determined by echocardiography in those with CHD. Fasting blood samples were processed for full blood counts and serum glucose, urea, creatinine, uric acid, and lipids (total cholesterol [TC], triglycerides [TG], high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein [LDL], and apolipoprotein B [apoB]), cTnI, BNP, and high-sensitivity (hs) CRP levels. The results were compared between groups, and the associations of BNP with other parameters were explored.In comparison to HC, the CHD group had a greater waist-hip ratio (WHR) (P0.01), worse atherogenic profile, worse renal function, and higher values for CRP and BNP (all P0.001). There were no significant differences in values for BNP related to age, diabetes, hypertension, WHR, and hematocrit, although there was a consistent trend in both HC and CHD groups toward a negative relationship of BNP with body mass, TG, and apoB levels, and a positive relationship with HDL, independent only for HDL and apoB on multiple logistic regression. No correlations could be established with cTnI, CRP, and LVEF. The patterns of cross-correlations did not differ significantly with diabetic status.In an Arab population with CHD, blood levels of BNP are higher than in a healthy control population and appear correlated to body mass and atherogenic lipids but not CRP, troponin, or ejection fraction. BNP levels did not appear to be influenced by the classical CHD risk factors of diabetes, hypertension, cigarette smoking, hematocrit, or WHR. The independent link with atherogenic dyslipidemia suggests that BNP is important in atherogenesis and may not be just an index of cardiac contractile dysfunction.

Insulin-like growth factors (IGF-I, IGF-II) and their binding protein (IGFBP-3) may be risk markers for coronary heart disease (CHD). This study aimed to assess the levels and determinants of the serum levels of IGF-I, IGF-II and IGFBP-3 in Arab patients with established CHD.Two groups of subjects were matched for age, gender, BMI and waist-hip ratio (WHR): (i) CHD (n = 105), median age 51.0 (range 40.0-60.0) years; (ii) controls (n = 97) aged 49.0 (range 37.0-60.0) years. We measured fasting serum levels of glucose and lipoproteins (total cholesterol, triglycerides, LDL, HDL, apo B), insulin, HOMA-IR, IGF-I, IGF-II and IGFBP-3 and compared the results between groups. The effects of body mass and the metabolic syndrome (MS) on IGF levels were also examined, and linear correlations were sought between the various parameters.The levels of IGF-I, IGF-II and IGFBP-3 were significantly lower (all p0.01) for the CHD group than for the control group. These differences were not influenced by BMI or with the presence of MS. In CHD, there were no significant correlations between levels of IGF-I and IGF-II and age, BMI, WHR, lipoprotein concentrations and insulin sensitivity, although IGFBP-3 had weakly significant relationships with some of the lipoproteins.Levels of IGF-I, IGF-II and IGFBP3 are reduced in male Arab patients with CHD, and did not appear influenced by traditional CHD risk factors such as age, BMI, insulin sensitivity and presence of MS. Perturbations in the IGF/IGFBP-3 axis may be potential additional targets for pharmacological manipulation in CHD.

Background: Insulin-like growth factors (IGFs) are believed to be important in brain development and repair following neuronal damage. It is also speculated that IGFs are involved in the association of foetal and pre-adult growth with schizophrenia (SZ). Methods: The aim of this study was to assess levels of IGF-I, IGF-II and IGF binding protein (IGFBP)-3 and their associations in male Arab patients with SZ (n=53) and healthy control subjects (HC; n=52). Anthropometric and demographic data were collected for each subject for whom blood specimens were analysed for serum lipoproteins, apolipoprotein B (apoB), IGF-I, IGF-II and IGFBP-3. Results: The SZ group had lower serum total cholesterol, apoB and uric acid levels than the HC group (p

The APOE gene locus has 3 major alleles, E3, E4 and E2, which variably influence coronary heart disease (CHD) risk. Plasma low-density lipoprotein (LDL) profile, another major CHD risk factor, is characterized on the basis of size and density into 2 main patterns: large buoyant LDL and small dense LDL. The latter has also been linked with increased CHD risk. This study investigates associations of specific APOE allelic patterns with LDL size and subfraction profiles in patients with CHD and healthy control subjects. We recruited 2 groups of male subjects: (A) 65 apparently healthy control subjects, median age, 39.0 years (range, 25.0-60.0 years); (B) 50 patients with CHD, median age, 54.0 years (range, 40.0-76.0 years). APOE genotypes were determined by validated polymerase chain reaction-restriction fragment length polymorphism methods, and LDL size and subfractions were assessed by a high-resolution, nongradient polyacrylamide gel electrophoresis technique (LIPOPRINT, Quantimetrix, Redondo Beach, CA). Lipid and other biochemical analyses were done by autoanalyzer techniques. The associations of specific APOE alleles and genotypes with LDL size and subfraction patterns were then assessed. As expected, patients with CHD had a worse atherogenic lipoprotein profile (waist-hip ratio, LDL, uric acid, and apolipoprotein B) than the controls. APOE genotype and allele frequencies were similar for both groups. In either group, median percent large buoyant LDL (pattern A) was greater in controls (51.0% vs 46.5%, P

Background The possible pathogenetic relationship between APOE genetic polymorphism and susceptibility to a variety of neurodegenerative disorders, including multiple sclerosis, is controversial. Previous studies have been conducted in Caucasian subjects, with little or no data on subjects from the Arabian Gulf. We compared the frequencies of specific APOE genotypes and alleles in patients with multiple sclerosis (MS) with frequencies observed in a healthy control Kuwaiti Arab population to relate APOE frequencies with specific identifiable clinical features of the disease. Methods Two groups of subjects were studied: (i) 39 (17 M, 22 F) patients with clinical evidence of MS; (ii) 106 apparently healthy Kuwaitis recruited as control subjects. The MS patients had detailed clinical and laboratory evaluations, and APOE genotypes were determined in all the subjects (patients and controls) by validated PCR methods. Differences in frequencies of APOE alleles and associations of specific alleles with clinical features were assessed. Results There were no significant differences in allele frequencies between patients and controls, although there was a statistically insignificant trend towards lower APOE2 allele frequency in the patients ( p =0.09). There was a significant association of the APOE4 allele with female gender in the patients ( p Conclusion In Kuwaitis, a population with low MS prevalence, no statistically significant associations between APOE genetic polymorphism and susceptibility to MS could be established, but there was a trend towards a lower APOE2 frequency with MS and towards increased frequency of APOE4 in female patients and with severe disease.

We have determined the allele and genotype frequencies at the hypervariable locus D1S80 in a native Kuwaiti population using the polymerase chain reaction technique and subsequent high resolution gel electrophoresis. In a sample of 200 individuals, 21 alleles and 57 genotypes were detected. The alleles with 18 and 24 repeat units were most common with frequencies of 0.188 and 0.408 respectively. The distribution of the observed genotypes was in agreement with the Hardy-Weinberg equilibrium prediction. The observed heterozygosity for the population sample was 0.80 with the allelic diversity of 0.781 +/- 0.029 and the power of discrimination was 0.94. The data obtained in this study are potentially useful for individual identification in forensic casework.

We report the allele and genotype frequencies in a sample of an unrelated native Kuwaiti population determined by the use of polymerase chain reaction (PCR) and reverse dot-blot analysis. This technique, involving the use of commercially available AmpliType HLA-DQ alpha forensic DNA amplification and typing kit, has permitted the definition of six alleles and 21 genotypes in a sample of 220 people. The allelic frequencies are in the range 5.7-27.5%. This locus demonstrated a heterozygosity of 0.80 with an allelic diversity of 0.81 and the power of discrimination (PD) was 0.93. The distribution of observed genotypes conformed to Hardy-Weinberg equilibrium thus indicating genetic equilibrium of the different variants. This population data should permit the use of HLA-DQ alpha marker for individual identification in forensic casework.

Incubation of rat liver cytosolic isocitrate dehydrogenase with N-ethylmaleimide (NEM) resulted in the inactivation of the enzyme following pseudo-first order kinetics. Isocitrate affords considerable protection against inactivation whereas NADP+ enhances modification of the enzyme, suggesting localization of the modified group at the active site. Correlation of loss of activity with incorporation of [14C]NEM indicated that two sulphydryl residues/sub-unit are modified of which only one is shown to be involved in catalysis. pH dependence of the inactivation process implicates a reactive group of pKa 8.1 in catalysis. We conclude that a unique cysteine residue is essential for maximal catalytic activity of isocitrate dehydrogenase.

The kinetics of a single turnover of enzyme-catalysed oxidative decarboxylation have been studied by mixing a stoichiometric complex of enzyme, isocitrate and Mg 2+ with large concentrations of NADP + in a stopped-flow apparatus, and monitoring the formation of NADPH by fluorescence measurements. A transient is revealed that exhibits enhanced nucleotide fluorescence and is not detectable by light absorption measurements. The results obtained with the largest NADP + concentrations, such that the product NADPH is largely displaced from its enzyme complex, show that a step that precedes the release of free NADPH is rate-limiting in the oxidative decarboxylation reaction under conditions of catalytic cycling. The rate constants for this step, tentatively identified as the formation of the complex of enzyme, Mg 2+ and NADPH from a precursor NADPH-containing complex, and for the dissociation of NADPH from this complex have been estimated from the integrated rate equation for a simple model for the product phase of the reaction, by methods of nonlinear regression analysis. In line with the conclusions from the preceding paper, it is suggested that formation of an abortive complex of enzyme, Mg 2+ , isocitrate and NADPH under catalytic cycling conditions serves to by-pass the potentially rate-limiting dissociation of NADPH from the enzyme-Mg 2+ -NADPH complex.

The kinetics of dissociation of NADPH from its complex with isocitrate dehydrogenase, and from the abortive complex of enzyme, Mg 2+ , isocitrate and NADPH, have been studied in phosphate and triethanolamine buffers by means of rapid fluorescence measurements. The reactions are complex, and it is suggested that a conformational equilibrium of each of the complexes is involved, and that this conformational change is also responsible for a slow approach to the steady-state rate of oxidative decarboxylation observed previously in triethanolamine buffer under certain conditions (K. Dalziel, N. McFerran, B. Matthews & C. H. Reynolds, Biochem . J . 171, 743‒750 (1978)). It is concluded that release of free NADPH product is not the rate-limiting step in oxidative decarboxylation in the steady state. The validity of the ligand displacement method used to measure the dissociation kinetics of the enzyme‒NADPH complex has been studied by computer simulation.

The branched chain 2-oxoacid dehydrogenase complexes of ox kidney [ 11, rat heart, kidney and liver [2-61 and rabbit liver [7] are inactivated by phosphorylation with ATPMg and some aspects of the regulation of the kinase reaction have been described [S]. Little is known of reactivation of phosphorylated complex, although its occurrence in mitochondria is documented 12-41. We show here that phosphorylated ox kidney BCDH complex is activated without dephosphorylation by a high speed supernatant fraction prepared from extracts of rat liver or kidney mitochondria. Activator was not detected in a similar fraction of rat heart mitochondria. Activator was thermolabile, non-diffusible by dialysis, inactivated by trypsin and precipitated by (NI&hS04. complex were omitted, in order to increase the yield of BCDH complex (S-IO-fold) and the rate of inactivation by MgATP ( -4-fold). Apparent first order rate constants for inactivation by MgATP ranged from l-3. Activity of pyruvate dehydrogenase complex was up to 80% of that of BCDH complex as estimated by the activity ratio with ketoleucine and pyruvate [I]. Pig heart pyruvate dehydrogenase complex was purified as in [9].

NADP+-linked isocitrate dehydrogenase from rat liver cytosol was purified (approximately 135-fold) to apparent homogeneity in 27% yield. The purified enzyme has specific activity of 73 units · mg− 1. The native enzyme showed an apparent Mr of 94,000 by gel filtration and was composed of two identical subunits of Mr 45,000 as judged by SDS/PAGE. In isoelectric focusing, a pI value of 5.7 was estimated for the enzyme.

The branched-chain 2 oxoacid dehydrogenase complex has been purified from well-washed ox-kidney mitochondria together with branched-chain dehydrogenase kinase. The complex was inactivated and phosphorylated by ATP in about 5 min at 30 degrees C. After hydrolysis of ATP by a contaminating ATPase (5-10 min) the complex was dephosphorylated and reactivated. Dephosphorylation and reactivation were linearly correlated. Reactivation was dependent upon Mg2+ (K0.5 greater than 1 mM) and inhibited completely by 50 mM fluoride. Reactivation and dephosphorylation are attributed to a mitochondrial branched-chain dehydrogenase phosphatase.

By fractional extraction of minced bovine heart muscle with iso-osmotic sucrose and phosphate buffer solutions, it is shown that less than 4% of the total citrate synthase in the tissue is in the cytosol. Using citrate synthase as a marker for broken mitochondria, two methods of fractionation of 750 x g supernatants from homogenates of bovine heart muscle show that 10% of the total fumarase and NADP-linked isocitrate dehydrogenase activities are present in the cytoplasm. Homogenates prepared by sonication and osmotic shock and by sand-grinding gave closely similar results as regards enzyme distributions and extent of mitochondrial breakage. The results are compared with those reported for other tissues.

The protein activator of phosphorylated branched-chain 2-oxo acid dehydrogenase complex was purified greater than 1000-fold from extracts of rat liver mitochondria; the specific activity was greater than 1000 units/mg of protein (1 unit gives half-maximum re-activation of 10 munits of phosphorylated complex). Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis gave two bands (Mr 47700 and 35300) indistinguishable from the alpha- and beta-subunits of the branched-chain dehydrogenase component of the complex. On gel filtration (Sephacryl S-300), apparent Mr was 190000. This and other evidence suggests that activator protein is free branched-chain dehydrogenase; this conclusion is provisional until identical amino acid composition of the subunits has been demonstrated. Activator protein (i.e. free branched-chain dehydrogenase) was inhibited (up to 30%) by NaF, whereas branched-chain complex was not inhibited. There was no convincing evidence for interconvertible active and inactive forms of activator protein in rat liver mitochondria. Activator protein was detected in mitochondria from liver (ox, rabbit and rat) and kidney (ox and rat), but not in rat heart or skeletal-muscle mitochondria. In rat liver mitochondrial extracts, branched-chain complex sedimented with the mitochondrial membranes, whereas activator protein remained in the supernatant. Activator protein re-activated phosphorylated (inactive) particulate complex from rat liver mitochondria, but it did not activate dephosphorylated complex. Liver and kidney, but not muscle, mitochondria apparently contain surplus free branched-chain dehydrogenase, which is bound by the complex with lower affinity than is the branched-chain dehydrogenase intrinsic to the complex. It is suggested that this functions as a buffering mechanism to maintain branched-chain complex activity in liver and kidney mitochondria.

A simple two-step method for the purification of malic enzyme from bovine heart mitochondria in high yield is described. It consists of successive affinity chromatography steps on immobilized C 8 -(aminohexyl)-NADP and N 6 -(aminohexyl)-ADP. The molecular weight estimated by gel filtration of the homogeneous enzyme is 250,000 and the subunit molecular weight by SDS-polyacrylamide gel electrophoresis is 59,000.