Association of the CD36 gene with impaired glucose tolerance, impaired fasting glucose, type-2 diabetes, and lipid metabolism in essential hypertensive patients

Essential hypertension is a common disorder that can increase the risk of type 2 diabetes (T2D). CD36 has been studied in patients with diabetes and hypertension extensively; however, few studies have focused on the relationship of the CD36 gene with impaired fasting glucose (IFG)/impaired glucose tolerance (IGT) or T2D in essential hypertension patients. To identify rs1049673 and rs1527483 in the CD36 gene conferring susceptibility to IFG/IGT and T2D, we conducted a case-control study in 1257 essential hypertension patients among the Han Chinese population (control: 676; IGT/IFG: 468; T2D: 113). We also evaluated the impact of two loci on insulin sensitivity, glucose tolerance and serum lipid. The major findings of this study were that rs1049673 was found associated with IFG/IGT and T2D in essential hypertension patients (Pco = 0.028; Pdom = 0.015). The rs1049673 G carriers showed significant higher Glu0 (βdom = 0.08 (0.01~0.16), Pdom = 0.045) and Lp(a) (βco = 0.04 (0.002~0.07), Pco = 0.041; βdom = 0.06 (0.01~0.12), Pdom = 0.032), and lower HDL by the linear regression with the adjustment for gender, age, BMI, and mean blood pressures. These findings provided evidence that the CD36 gene may play some role in the pathogenesis of IFG/IGT and T2D in essential hypertension patients.

Association of KCNJ11 with impaired glucose regulation in essential hypertension

KCNJ11 is one of the candidate genes for type 2 diabetes, confirmed by genome wide association study, but there are little data on the relationship between KCNJ11 and impaired glucose regulation in essential hypertension patients. To identify the effect of E23K and I337V in the KCNJ11 gene on susceptibility to impaired glucose regulation, we conducted a case control study in 1125 essential hypertension patients with or without impaired glucose regulation among a Han Chinese population. We also evaluated the impact of two SNPs on insulin sensitivity and glucose tolerance estimated through an oral glucose tolerance test. In our case control study, no association of E23K and I337V with impaired glucose regulation was found using any genotypic models. However, lysine carriers of E23K showed a significant association with decreased insulin (30 min) and Cederholm index, and valine carriers of I337V showed association with a lower Cederholm index. All the quantitative tests were performed by linear regression, with adjustment for gender, age, body mass index, blood pressure, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker treatment. These findings provided evidence that the KCNJ11 gene plays a role in the pathogenesis of decreased insulin sensitivity in essential hypertension patients.

Effect of bio-treatment on the lipophilic and hydrophilic extractives of wheat straw

Wheat straw, an important papermaking raw material in China, was treated with a white-rot fungus of Phanerochaete chrysosporium ME446, and the lipophilic and hydrophilic extractives from the control and bio-treated samples were analyzed by GC and GC-MS. Bio-treatment of wheat straw could alter the chemical composition of both the lipophylic and hydrophilic extractives. Sugars and phenolic substances such as coniferyl alcohol, 4-hydroxycinnamic acid, 1-guaiacylglycerol and ferulic acid were substantially degraded or consumed by the fungus. More lipophilic substances such as wax, glycerides and steryl esters were degraded into the corresponding components, resulting in much higher concentrations of fatty acids and sterols in the bio-treated samples. Obviously, the bio-treatment of wheat straw was of benefit to pitch control in pulping and papermaking processes, in the view of degradation of the more lipophilic substances. In addition, the bio-treatment could increase the lignin concentration in hot-water extractives of wheat straw.

Novel concentration-killing curve method for estimation of bactericidal potency of antibiotics in an in vitro dynamic model

The bactericidal pharmacodynamics of antibiotics against Escherichia coli were analyzed by a concentration-killing curve (CKC) approach, and the novel parameters median bactericidal concentration (BC(50)) and bactericidal intensity (r) for bactericidal potency were proposed. By using the agar plate method, about 500 E. coli cells were inoculated onto Luria-Bertani plates containing a series of antibiotic concentrations, and after 24 h of incubation at 37 degrees C, all the viable colonies were enumerated. This resulted in a sigmoidal CKC that could be perfectly fitted (R(2) > 0.9) with the function N = N(0)/[1 + e(r(x - BC(50)))], where N is number of colonies surviving on each plate with an x series of concentrations of an antibiotic, and N(0) represents the meaningful inoculum size. Construction of the CKC method was based on the bactericidal effect of each antibiotic against the bacterial strain versus the concentration in two dimensions and may be a more valid, accurate, and reproducible method for estimating the bactericidal effect than the endpoint minimum bactericidal concentration (MBC) method. Mathematically, the CKC approach was point symmetrical toward its inflexion (BC(50), N(0)/2); thus, 2BC(50) could replace MBC. The parameter BC(1) can be defined as BC(50) + [ln(N(0) - 1)/r], which is the drug concentration at which only one colony survived and which is the least critical value of MBC in the CKC. The variate r, which determined the tangent slope on inflexion when N(0) was limited, could estimate the bactericidal intensity of an antibiotic. This verified that the CKC approach may be useful in studies with other classes of antibiotics and has considerable value as a tool for the accurate and proper administration of antibiotics.

Volumetric productivity improvement for endoglucanase of Trichoderma pseudokoingii S-38

AIMS

The objective of this study was to design an economically feasible process for endoglucanase (EG) production.

METHODS AND RESULTS

Trichoderma pseudokoingii S-38 EG synthesis was studied. Initially, either glucose at 2.5, 5 or 10 g l-1, or cellulose powder (CF11) at 5 g l-1 was used as the sole carbon source. The results showed that enzyme synthesis and biomass formation were closely correlated, and both were affected by the carbon source. To improve EG volumetric product efficiency, a new technique was developed. Glucose and CF11 (2.5 and 5 g l-1, respectively) were used as initial carbon source, and glucose was added at 2.5 g l-1 day-1. EG activity, volumetric and specific EG productivities were 6.17 IU l-1, 53 IU l-1 h-1 and 114.3 IU (g cell protein)-1 h-1, respectively. Batch production in a 2-l laboratory fermenter confirmed the advantage of the technique. The product contained 10.86 IU ml-1 EG activity in 88 h. The volumetric and specific EG productivities were 123.4 IU l-1 h-1 and 177.8 IU (g cell protein)-1 h-1, respectively.

CONCLUSIONS

These results suggest that optimization of the ratio of glucose to CF11 for balancing the induction and growth rate in the production of EG may lead to technical and economical benefits.

SIGNIFICANCE AND IMPACT OF THE STUDY

A new technique was developed for the production of EG which improves both the volumetric product efficiency and the specific activity.

[Identification of genes related to cell phenotypic transition by differential display analysis]

To identify the genes that are differentially expressed during the phenotypic transition from vascular adventitial fibroblasts to myofibroblasts, the adventitial fibroblasts were cultured from rat thoracic aorta, and myofibroblasts were obtained by treatment of fibroblasts with TGF-beta1. Differential display PCR (DD-PCR) was used to screen for differentially expressed genes by comparison of mRNA extracted from the two cell populations. Bands upregulated or downregulated on DD gels were excised, reamplified, cloned and sequenced. DD results were verified by quantitative PCR and Northern blot analysis.Antisense oligonucleotide was transfected to study the effect of osteopontin on migration of AF. Differential display showed a significant difference in gene expression profile between the two cell types. A transcript that was downregulated in myofibroblasts showed high DNA sequence homology to part of the gene for NADH dehydrogenase subunit 5. An upregulated transcript showed significant sequence homology to osteopontin gene. Quantitative PCR and Northern blot analysis confirmed the DD results. Among the other differential bands detected, 4 candidate sequences showed no homology to the known genes. The AF numbers of migration were significantly decreased by use of OPN antisense oligonucleotide. This study suggests that the downregulation of gene encoding NADH dehydrogenase subunit 5 and upregulation of osteopontin gene and several other unknown genes may be involved in the phenotypic transition of adventitial fibroblasts to myofibroblats. Inhibition of the expression of OPN may play an important role in the process of vascular remodeling.

Diagnosis of Liddle syndrome by genetic analysis of beta and gamma subunits of epithelial sodium channel--a report of five affected family members

OBJECTIVE

To screen the gene mutation in beta and gamma subunits of the epithelial sodium channel (ENaC) of a Chinese family, some of whose members are clinically diagnosed as suffering from Liddle syndrome.

METHODS

Twelve family members were recruited to the study. Among them, two brothers had been clinically diagnosed as suffering from Liddle syndrome. Peripheral blood samples were collected from all members of the family and total genomic DNA was prepared for genetic analysis. Polymerase chain reaction (PCR) was used for amplifying the last exon of beta (codon 513-673) and gamma (codon 503-632) subunits of the ENaC gene. PCR products were purified and subjected to a direct DNA sequence analysis.

RESULTS

Genetic analysis of the beta ENaC gene revealed a missense mutation of CCC to CTC at codon 616 in four middle-aged men of the second generation and one young woman of the third generation. There was no mutation of the gamma ENaC gene in any of the individuals examined.

CONCLUSION

Through direct DNA sequencing analysis, we diagnosed the disease present in five members of a Chinese family as Liddle syndrome, and excluded it in some other young offspring suffering from the monogenic disease. Our results provide further evidence that Pro616 is a critical amino acid that has a key role in the inhibition of sodium channel activity.

[Studies on submerged fermentation of alkaline beta-1,4-glycanases by Bacillus pumilus A-30]

The effects of stirring rate, pH control and feed time of (NH4)2SO4 on beta-1,4-glycanases were investigated. The operating conditions of batch fermentation and fed-batch culture were optimized. The results showed there were a large amount of bacterial cells adsorbing on the surface of wheat bran, and stirring rate had a pronounced influence on the adsorption and the production of beta-1,4-glycanases. The uncontrolled pH could promote the induction of beta-1,4-glycanases. When (NH4)2SO4 was fed at a constant rate in the earlier age, and regulated later by determining the content of (NH4)2SO4, xylanase and CMCase activity could reach 616 IU/mL and 1.33 IU/mL respectively.

The inhibitory mechanisms of amlodipine in human vascular smooth muscle cell proliferation

The abnormal proliferation of vascular smooth muscle cells (VSMCs) is closely related to vascular diseases. There is growing evidence that calcium antagonists inhibit VSMC growth/proliferation, yet their molecular mechanisms remain to be determined. Recent reports suggest that p42/p44 mitogen-activated protein kinases (MAPKs) play an important role in cell growth and proliferation induced by growth factors. This study was designed to determine whether these MAPKs are involved in VSMC proliferation induced by basic fibroblast growth factor (bFGF) and to examine the inhibitory effect of amlodipine. Human VSMCs were obtained from inner mammary artery. p42/p44 MAPKs activity was measured by immunoblotting assay using anti-p42/p44 phospho-MAPK antibody. 1) bFGF (20 ng/ml) significantly activated p42/p44 MAPKs with a peak time of 5-15 min, which was maintained for 3 h. PD98059 (100 nM-10 microM), a specific inhibitor of MAPK kinase, inhibited bFGF-induced p42/p44 MAPKs activation in a dose-dependent manner. 2) Amlodipine (1-100 nM) dose-dependently inhibited p42/p44 MAPKs activation by bFGF. 3) Amlodipine (10 nM) could inhibit both short-term and long-term p42/p44 MAPKs activation by bFGF. Our results indicate that bFGF could activate p42/p44 MAPKs. Amlodipine, which could inhibit bFGF-induced human VSMC proliferation, inhibited both short-term and sustained p42/p44 MAPKs activation by bFGF, suggesting that bFGF-induced VSMC proliferation may be related to p42/p44 MAPKs activation, and that the antiproliferative effect of amlodipine may be related to its inhibition of p42/p44 MAPKs activation.

L-phenylalanine and smooth muscle cell proliferation from SHR and WKY rats

Cell growth and proliferation were evaluated in cultured vascular smooth muscle cells (VSMCs) isolated from spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) rat aortae by measuring [3H]-thymidine incorporation into newly synthesized DNA and by determining cell number, respectively. The results showed that in cultures from both rat strains (1) serum-, basic fibroblast growth factor (bFGF)- and thrombin-induced DNA synthesis were inhibited by L-phenylalanine dose-dependently; (2) L-phenylalanine inhibited cell proliferation in response to serum in a concentration-dependent manner; (3) L-phenylalanine inhibited serum-induced proto-oncogene c-fos and c-myc expression; (4) L-tyrosine, L-histidine and D-phenylalanine failed to mimic the inhibitory effect of L-phenylalanine. All these data demonstrate that L-phenylalanine could exert a direct and specific antiproliferative effect on VSMCs suggesting that such effect can account for the antihypertensive action of this amino acid observed in SHR.

Cellobiose dehydrogenase from Schizophyllum commune: purification and study of some catalytic, inactivation, and cellulose-binding properties

Cellobiose dehydrogenase (CDH) of Schizophyllum commune was purified to homogeneity. It is a glycoprotein with a molecular mass of 102, 000. Cellulosic substrates can serve as substrates for CDH. Cytochrome c, dichlorophenol-indophenol, ferricyanide, and oxygen can be reduced by the enzyme. CDH is stable in the pH range of 4-11 and up to 35 degrees C. The enzyme keeps active at high concentrations of H2O2. In the presence of cellobiose and Fe3+, incubation of CDH resulted in its inactivation and the degree of the inactivation was dependent mainly on the amount of CDH and cellobiose present. CDH has a distinct and specific affinity to cellulose and showed the strongest binding to acid-treated cellulose. The adsorption isotherm data fitted the Langmuir-type equation. The uv-visible spectra of the oxidized and reduced states of CDH showed a typical cytochrome b-type pattern. Addition of dithionite eliminated the adsorption between 440 and 500 nm, which indicates the presence of a flavin group in CDH.

Expression of protein kinase C gene in the brain and heart of spontaneously hypertensive rats

1. The aim of this study was to investigate protein kinase C (PKC) gene expression in spontaneously hypertensive rats (SHR). 2. Using the PKC oligodeoxyribonucleotide probes (gamma, epsilon), we detected PKC isoforms gene expression in the heart and brain of 4 and 20 week old SHR with those of age-matched Wistar-Kyoto (WKY) rats by northern blot analysis. 3. In the cerebral cortex, there were significantly increased levels of expression of the Ca2+-dependent isoform PKC-gamma in 4 and 20 weeks SHR compared with that of WKY, while Ca2+ -independent isoform PKC-epsilon did not differ between SHR and WKY. 4. In ventricular myocytes, there was a significant expression of the Ca2+-independent isoform PKC-epsilon in 4 and 20 week old SHR compared with that of WKY, while Ca2+ -dependent isoform PKC-gamma could not be detected in the same extracts of SHR or WKY. 5. We conclude that both of the Ca2+ -dependent and Ca2+ -independent PKC could be involved in the pathogenesis of SHR. Ca2+ -dependent PKC-gamma may be mainly involved in the modulation of blood pressure in the level of the central nervous system, while Ca2+ -independent PKC-epsilon could be related to the genetic myocardial hypertrophy.