Sucrose isomerase and its mutants from Erwinia rhapontici can synthesise α-arbutin

Sucrose isomerase (SI) from Erwinia rhapontici is an intramolecular isomerase that is normally used to synthesise isomaltulose from sucrose by a mechanism of intramolecular transglycosylation. In this study, it was found that SI could synthesise α-arbutin using hydroquinone and sucrose as substrates, via an intermolecular transglycosylation reaction. Five phenylalanine residues (F185, F186, F205, F297, and F321) in the catalytic pocket of SI were chosen for sitedirected mutagenesis. Mutants F185I, F321I, and F321W, whose hydrolytic activities were enhanced after the mutation, could synthesise α-arbutin through intermolecular transglycosylation with a more than two-fold increase in the molar transfer ratio compared with wild type SI. The F297A mutant showed a strong ability to synthesise a novel α-arbutin derivative and a four-fold increase in its specific activity for intermolecular transglycosylation over the wild type. Our findings may lead to a new way to synthesise novel glucoside products such as α-arbutin derivatives by simply manipulating the Phe residues in the catalytic pocket. From the structure superposition, our strategy of manipulating these Phe residues may be applicable to other similar transglycosylating enzymes.

β-Benzene hexachloride induces apoptosis of rat Sertoli cells through generation of reactive oxygen species and activation of JNKs and FasL

β-benzene hexachloride (β-BHC), the major metabolite of benzene-hexachloride (BHC), is a weak estrogen-like chemical. It is a known persistent organic pollutant and male reproductive toxicant. However, the mechanism by which β-BHC exposure causes male reproductive toxicity remains unknown. In the present study, rat Sertoli cells were used to investigate the molecular mechanism involved in β-BHC-induced toxicity in male reproductive system. The results indicated that β-BHC exposure at over 30 μM showed the induction of apoptotic cell death. β-BHC could induce elevation in reactive oxygen species (ROS) generation, increase in the leakage rate of LDH and MDA level, and decrease in SOD activity. In addition, there was an increase in the cellular levels of phospho-JNKs and FasL in the β-BHC-induced apoptosis; and a significant reduction of procaspase-3 and -8 was observed over 30-μM β-BHC treatment. The translocation of NF-κB enhanced with the increase of concentration of β-BHC. Furthermore, NAC administration, a scavenger of ROS, reversed β-BHC-induced apoptosis effects via inhibition of JNKs activation, FasL expression, and NF-κB translocation. These results lead us to speculate that ROS generation may play a critical role in the initiation of β-BHC-induced apoptosis by activation of the JNKs, translocation of NF-κB, expression of FasL, and further activation of caspase cascade.

MicroRNA-21 expression in neonatal blood associated with antenatal immunoglobulin E production and development of allergic rhinitis

BACKGROUND

The prevalence of allergic diseases has increased in the past decades. It is unknown whether expression of certain microRNAs (miRNAs) in neonatal leucocytes is correlated to IgE production and/or allergic diseases.

OBJECTIVE

This study investigated the association of miRNA expression in neonatal leucocytes with cord blood IgE (CBIgE) elevation and development of allergic disease.

METHODS

We screened for the expression of a panel of 157 miRNAs in mononuclear leucocytes from human umbilical cord blood (CB) samples with elevated CBIgE and tracked the association of down-regulated miRNA expression to the miRNA-targeted gene expression and to children with allergic rhinitis (AR).

RESULTS

Among the initial screen of 10 CB samples with elevated CBIgE, expression of eight of the 157 miRNAs was low. Of these eight down-expressed miRNAs, three remained down-regulation in a validation with other 20 CB samples, and two of the three miRNAs, miR-21 and miR-126, were significantly lower in monocytes from AR children. Further analysis of mRNA expression of the miR-21-targeted genes identified that TGFBR2 expression on monocytes was significantly up-regulated in CB with elevated CBIgE, and in AR patients. Transfection of miR-21 precursor into monocytes from patients with AR increased miR-21 expression and decreased TGFBR2 expression.

CONCLUSION

This study demonstrated the first in the literature that lower miR-21 expression in CB and increased TGFBR2 expression is associated with antenatal IgE production and development of AR.

Gene-gene and gene-environment interactions on IgE production in prenatal stage

BACKGROUND

Prevalence of allergic diseases in children has increased worldwide over the past decades. Allergy sensitization may occur in fetal life. This study investigated whether gene-gene and gene-environment interactions affected cord blood IgE (CBIgE) levels.

METHODS

A total of 575 cord blood DNA samples were subjected to a multiplex microarray for 384 single nucleotide polymorphisms (SNPs) in 159 allergy candidate genes. Genetic association was initially assessed by univariate and multivariate analyses. Multifactor dimensionality reduction (MDR) was used to identify gene-gene and gene-environment interactions. Environmental factors for analysis included maternal atopy, paternal atopy, parental smoking, gender, and prematurity.

RESULTS

Twenty-one SNPs in 14 genes were associated with CBIgE elevation (>or =0.5 KU/l) in univariate analysis. Multivariate analysis identified eleven genes (IL13, IL17A, IL2RA, CCL17, CXCL1, PDGFRA, FGF1, HAVCR1, GNAQ, C11orf72, and ADAM33) which were significantly associated with CBIgE elevation. MDR analyses of gene-gene interactions identified IL13 interacted with IL17A and/or redox genes on CBIgE elevation with the prediction accuracy of 62.52%. Analyses of gene-environment interactions identified that maternal atopy combined with IL13, rs1800925 and CCL22, rs170359 SNPs had the highest prediction accuracy of 67.15%. All the high and low risk classifications on gene-gene and gene-environment interactions by MDR analyses could be validated by Chi-square test.

CONCLUSIONS

Gene-gene (e.g. immune and redox genes) and gene-environment (e.g. maternal atopy and FGF1or redox genes) interactions on IgE production begin in prenatal stage, suggesting that prevention of IgE-mediated diseases may be made possible by control of maternal atopy and redox responses in prenatal stage.

Extracorporeal shockwave for hip necrosis in systemic lupus erythematosus

Patients with systemic lupus erythematosus (SLE) frequently received corticosteroid therapy, resulting in osteonecrosis of the femoral head (ONFH). Prior studies demonstrated the effectiveness of extracorporeal shockwave treatment (ESWT) for ONFH.. This study evaluated the effectiveness of ESWT for ONFH in patients with SLE. We studied 39 patients, including 15 patients with SLE (26 hips) and 24 controls (29 hips). To each affected hip we applied ESWT (6000 impulses at 28 kV in a single session). Patients were ambulated with partial weight bearing for 4-6 weeks. The primary endpoint was the need for hip replacement. The secondary endpoints were improvement in hip pain and function and image changes on X-ray and MRI. Patients received total hip replacement in 12% of patients with SLE and in 14% of controls (P = 0.802). There was no statistically significant difference in pain scores (0.86 vs. 0.89; P = 0.467) and function scores (89% vs. 91%; P = 0.194) between patients with SLE and controls. SLE response to ESWT for ONFH is comparable with ONFH in patients without SLE.

[Effects of p,p'-DDE on expression of inhibin B in sertoli cells of rats]

OBJECTIVE

To study the effects of p,p'-DDE on the expression of inhibin B in sertoli cells of rats.

METHODS

Sertoli cells were separated and cultured from testicular tissue of rats, and ensured the dose of test materials by MTT test, and RT-PCR were measured on the changes of inhibin B expression.

RESULTS

The results indicated that there was high difference in middle and high dose groups in comparison with control group (P < 0.05), and there were statistical significance in comparison with low dose group, and the gray scale of inhibin B decreased with the increase dose of p,p'-DDE.

CONCLUSION

The results indicated that p,p'-DDE could inhibit the expression of inhibin B.

p,p'-DDE induces mitochondria-mediated apoptosis of cultured rat Sertoli cells

p,p'-Dichlorodiphenoxydichloroethylene (p,p'-DDE), the major metabolite of dichlorodiphenoxytrichloroethane (DDT), is a known persistent organic pollutant and male reproductive toxicant. However, the mechanism underlying male reproductive toxicity of p,p'-DDE remains limited. In the present study, Sertoli cells were used to investigate the molecular mechanism involved in p,p'-DDE's male reproductive toxicity. Results showed that p,p'-DDE exposure at over 30 microM showed induction of apoptotic cell death. p,p'-DDE could induce mitochondria-mediated apoptotic changes including elevation in reactive oxygen species (ROS) generation, decrease in mitochondrial membrane potential (DeltaPsi(m)), and release of cytochrome c into the cytosol, which could be blocked by antioxidant agent N-acetyl-l-cysteine (NAC). In addition, elevated ratios of Bax/Bcl-w and Bak/Bcl-w and cleavages of procaspase-3 and -9 were induced by p,p'-DDE treatment. All of the results suggested that ROS generation may play a critical role in the initiation of p,p'-DDE-induced apoptosis by mediation of the disruption of DeltaPsi(m), the release of cytochrome c into the cytosol and further the activation of caspase cascade.

Regular Tai Chi Chuan exercise improves T cell helper function of patients with type 2 diabetes mellitus with an increase in T-bet transcription factor and IL-12 production

BACKGROUND

Exercise has been shown to be beneficial in the treatment of type 2 diabetes mellitus (DM); its benefit to immune function, however, remains to be determined.

OBJECTIVE

This study investigated the effect of a 12-week course of Tai Chi Chuan (TCC) exercise on T cell helper (Th) reaction in patients with type 2 DM.

METHODS

A case-control study was performed in 30 pairs of patients with type 2 DM and normal age-matched adults. Fasting blood glucose, HbA1c, mediators (interleukin (IL)-12, IL-4 and transforming growth factor (TGF)beta) and transcription factors (T-bet, GATA-3 and FoxP3) of Th1/Th2/T regulatory (Treg) reaction were measured before and after a 12-week TCC exercise programme.

RESULTS

Fasting glucose and HbA1c levels in the patients with type 2 DM were significantly higher than in age-matched controls before exercise. After TCC exercise, HbA1c levels in patients with type 2 DM significantly decreased (7.59 (0.32)% vs 7.16 (0.22)%; p = 0.047) and blood levels of IL-12 increased significantly (5.96 (1.10) vs 12.96 (3.07); p = 0.035). To study the molecular Th1/Th2/Treg reaction, patients with type 2 DM were found to have lower T-bet but not GATA-3 or FoxP3 expression than normal controls before TCC exercise. After the 12-week TCC exercise T-bet expression significantly increased in patients with type 2 DM.

CONCLUSIONS

A 12-week TCC exercise programme decreases HbA1c levels along with an increase in the Th1 reaction. A combination of TCC with medication may provide an even better improvement in both metabolism and immunity of patients with type 2 DM.

[Mechanisms of mitogen-activated protein kinase pathway in male reproductive toxicity induced organochlorine pesticides]

Mitogen-activated protein kinase pathway may closely associated with cell growth, differentiation and apoptosis, it may play an important role in cell death. With growing evidences from in vitro test, recently it demonstrated that the MAPK play a key role in the reproductive toxicity induced organochlorine pesticides and also showed that the products of Reactive Oxygen Species (ROS) induced organochlorine pesticides in these process. The relationship between MAPK and their activation results in apoptosis induced organochlorine pesticides, for further clarification of the mechanism of male reproductive toxicity induced organochlorine pesticides.

Effects of fluoride on the expression of NCAM, oxidative stress, and apoptosis in primary cultured hippocampal neurons

The mechanisms underlying the neurotoxicity of endemic fluorosis still remain unknown. To investigate the expression level of neural cell adhesion molecules (NCAM), oxidative stress, and apoptosis induced by fluoride, the primary rat hippocampal neurons were incubated with 20, 40, and 80 mg/l sodium fluoride for 24 h in vitro. The results showed that the cell survival rate in the 80 mg/l fluoride-treated group was significantly lower than that of the control group. Forty and 80 mg/l of fluoride induced significantly increased lactate dehydrogenase release, intracellular reactive oxygen species, and the percentage of apoptosis. Compared with control group, the malondialdehyde levels were significantly elevated while glutathione levels and glutathione peroxidase activities were decreased in all fluoride-treated groups, accompanied by the markedly reduced superoxide dismutase activity in 80 mg/l fluoride-treated group. With respect to NCAM mRNA expression levels, a significant dose-dependent decrease was observed in 40 and 80 mg/l fluoride-treated groups against the control group. In addition, as compared to the control group, the protein expression levels of NCAM-180 in 40 and 80 mg/l fluoride-treated groups, NCAM-140 in all fluoride-treated groups, and NCAM-120 in the 80 mg/l fluoride-treated group were significantly decreased. Our study herein suggested that fluoride could cause oxidative stress, apoptosis, and decreased mRNA and protein expression levels of NCAM in rat hippocampal neurons, contributing to the neurotoxicity induced by fluoride.

Interaction of maternal atopy, CTLA-4 gene polymorphism and gender on antenatal immunoglobulin E production

BACKGROUND

Genetic heritability and maternal atopy have been correlated to antenatal IgE production, but very few studies have studied gene-maternal atopy interaction on antenatal IgE production. This study investigated the interaction of CTLA-4 polymorphism with prenatal factors on the elevation of cord blood IgE (CBIgE).

METHODS

Pregnant women were antenatally recruited for collection of prenatal environmental factors by a questionnaire. Umbilical cord blood samples were collected for CBIgE detection by fluorescence-linked enzyme assay and CTLA-4 polymorphism measurement by restriction fragment length polymorphism.

RESULTS

A total of 1104 pregnant women initially participated in this cohort study, and 898 of them completed cord blood collection. 21.4% of the newborns had elevation of CBIgE (>or=0.5 kU/L). The CTLA-4+49A allele (P=0.021), maternal atopy (P<0.001) and gender (P=0.034), but not the CTLA-4+49G allele, -318C allele, -318T allele, parental smoking or paternal atopy, were significantly correlated with the CBIgE elevation in multivariate analysis. A dichotomous analysis of gene-maternal atopy interactions identified maternal atopy and CTLA-4+49A allele had an additive effect on the CBIgE elevation, especially prominent in male newborns; and in the absence of maternal atopy, CTLA-4+49GG genotype had a protective effect on CBIgE elevation in female newborns.

CONCLUSIONS

Maternal but not paternal atopy has significant impacts on CBIgE elevation depending on gender and CTLA-4+49A/G polymorphism of newborns. Control of maternal atopy and modulation of CTLA-4 expression in the prenatal stage may be a target for the early prevention of perinatal allergy sensitization.

Dose-effect relationship between drinking water fluoride levels and damage to liver and kidney functions in children

Although a dose-effect relationship between water fluoride levels and damage to liver and kidney functions in animals has been reported, it was not demonstrated in humans. To evaluate the effects of drinking water fluoride levels on the liver and kidney functions in children with and without dental fluorosis, we identified 210 children who were divided into seven groups with 30 each based on different drinking water fluoride levels in the same residential area. We found that the fluoride levels in serum and urine of these children increased as the levels of drinking water fluoride increased. There were no significant differences in the levels of total protein (TP), albumin (ALB), aspartate transamine (AST), and alanine transamine (ALT) in serum among these groups. However, the activities of serum lactic dehydrogenase (LDH), urine N-acetyl-beta-glucosaminidase (NAG), and urine gamma-glutamyl transpeptidase (gamma-GT) in children with dental fluorosis and having water fluoride of 2.15-2.96 mg/L and in children having water fluoride of 3.15-5.69 mg/L regardless of dental fluorosis were significantly higher than children exposed to water fluoride of 0.61-0.87 mg/L in a dose-response manner. In contrast to children with dental fluorosis and having water fluoride of 2.15-2.96 and 3.10-5.69 mg/L, serum LDH activity of children without dental fluorosis but exposed to the same levels of water fluoride as those with dental fluorosis were also markedly lower, but the activities of NAG and gamma-GT in their urine were not. Therefore, our results suggest that drinking water fluoride levels over 2.0mg/L can cause damage to liver and kidney functions in children and that the dental fluorosis was independent of damage to the liver but not the kidney. Further studies on the mechanisms and significance underlying damage to the liver without dental fluorosis in the exposed children are warranted.

[Study on reproductive and developmental toxicity of the pregnant mice and their foetus co-administered by p, p'-DDE and beta-BHC]

OBJECTIVE

To explore effects of p, p'-DDE and beta-BHC on reproduction and development in mice.

METHODS

The pregnant Kunming SPF mice of 12 to 14 days were co-administered by oral gavage for 3 days at different concentrations of 0, 1, 5 and 10 mg/kg bw of p, p'-DDE and beta-BHC. The concentrations of estradiol (E2) and progesterone (P) in sera of the dosed mice were determined by the Serozyme kits (Bio-Ekon biotechnology Co., Beijing, China), following the procedures described by the manufacturer. RT-PCR was employed to detect abundant expression of alpha-estrogen receptor (alpha-ER) gonadtropin releasing hormone (GnRH) and beta-endorphin (beta-EP) mRNA in placentae.

RESULTS

(1) Reproductive effects: with increase of the administered p,p'-DDE and P-BHC,the organ coefficient of uterus and its intraluminal fluid increased, the unterine nidation quantity decreased, the anogenital distance (AGD) and ratio of female to male raised, the concentration of estradiol and progesterone in sera of the dosed mice went up, and the abundant expression of alpha-ER and GnRH mRNA rised while beta-EP dropped in placentae in a dose-dependant manner. Significant difference of these indexes were found between the treat groups and control (P < 0.05). (2) Developmental effects: with increase of the administered p,p'-DDE and beta-BHC, the gained weights of pregnant mice reduced, organ coefficient of liver increased,the quantity of live foetus decreased, the times of adverse pregnancy outcome went up, and the percent of female foetus increased. They all presented a dose-effect relation and significance of difference (P < 0.05).

CONCLUSION

p, p'-DDE and beta-BHC disrupt reproductive function, thereby result in dysreproduction and maldevelopment, and unbalance of ratio of female to male.

[Effects of selenium on expression of TERT, c-Myc and p53 induced by cadmium in rat liver]

OBJECTIVE

To study the effects of sodium selenite on expression of telomerase reverse transcriptase mRNA, c-Myc and p53 induced by cadmium chloride in rat liver.

METHODS

Male SD rats were divided randomly into 6 groups, each group had 5 animals. The groups comprised the control group, Se group (5 micromol/kg sodium selenite), 5 micromol/kg cadmium chloride group, 10 micromol/kg cadmium chloride group, Se (5 micromol/kg sodium selenite) + 5 micromol/kg cadmium chloride group, Se (5 micromol/kg sodium selenite) + 10 micromol/kg cadmium chloride group. After 48 hours of the first injection, the expression of TERT mRNA was measured with RT-PCR and c-Myc, and p53 proteins were measured by immunohistochemistry method.

RESULTS

Compared with control group, the expression of TERT was increased in 5 micromol/kg Cd group and 10 micromol/kg Cd group, c-Myc protein was increased in 10 micromol/kg Cd group, and the expression of p53 protein was increased in 5 micromol/kg group and 10 micromol/kg Cd group. TERT expression in Se + 10 micromol/kg Cd group was lower than that of 10 micromol/kg Cd group significantly. c-Myc protein was decreased in Se + 10 micromol/kg Cd group compared with 10 micromol/kg Cd group. p53 protein of Se + 5 micromol/kg Cd group and Se + 10 micromol/kg Cd group were decreased significantly compared with 5 micromol/kg Cd group and 10 micromol/kg Cd group respectively.

CONCLUSION

The cadmium at the doses of between 5 and 10 micromol/kg can activate TERT and up-regulate c-Myc and p53 proteins. The selenium at the dose of 5 micromol/kg has the antagonistic effect on expression of TERT, c-Myc and p53 induced by cadmium in rat liver.

Effects on protein and mRNA expression levels of p53 induced by fluoride in human embryonic hepatocytes

We investigated the effects of protein and mRNA expression levels on p53 induced by fluoride in human embryo hepatocyte L-02 cells. The protein and mRNA levels of p53 in L-02 cells were measured after in vitro cultured L-02 was exposed to sodium fluoride at different doses (40, 80, and 160 microg/ml) for 24 h. The results showed that the cell survival rate of L-02 cells in the high dose fluoride group was significantly lower than that of the control group. The protein expression levels of p53 in the middle and high dose fluoride group were significantly higher than in the control group and elevated with increasing fluoride concentration. The mRNA expression levels of p53 in the fluoride groups were markedly higher than in the control group. The mRNA expression level of p53 in the high dose fluoride group was however lower compared to the middle dose fluoride group, but similar to the low dose fluoride group. These finding suggest that fluoride can decrease the L-02 cells survival rate and induce protein and mRNA expressions of p53; however, there is no consistency between the protein expression level of p53 and the mRNA expression level.

Increased plasma concentration of nitric oxide in type 2 diabetes but not in nondiabetic individuals with insulin resistance

OBJECTIVE

Insulin resistance (IR) is a key element in the pathogenesis of type 2 diabetes. The results of recent experiments on insulin-mediated vasodilatation have suggested that vascular insensitivity is a component of IR. However, it is still controversial that patients with type 2 diabetes have a decreased ability of insulin to increase endothelial nitric oxide (NO) release.

METHOD

Plasma concentration of NO was examined in 26 patients with type 2 diabetes and 78 nondiabetic volunteers during an insulin suppression test. The test measured the efficacy of insulin in promoting disposal of the infused glucose load, in which the steady state plasma glucose (SSPG) during the 150-180 min of the test was used as an index of IR. Plasma NO levels were assayed by measurement of the stable end products of their metabolism. Comparison of plasma NO levels between groups were performed by Mann-Whitney test and relationships between SSPG and different variables were analyzed by partial correlations.

RESULTS

Our results showed that the plasma NO levels were significantly higher in the diabetic group. When the nondiabetic subjects were analyzed according to their SSPG levels, there was no difference of plasma NO levels between those with SSPG>160 mg/dl and those with SSPG<160 mg/dl. There were also no difference of NO levels between those with a family history of type 2 diabetes and those without. In the nondiabetic group, SSPG correlated with BMI, fasting insulin, triglyceride and HDL-cholesterol, but neither with plasma NO levels nor fasting plasma glucose.

CONCLUSION

Our data suggests that the impairment of NO activity in patients with type 2 diabetes is due to an impaired effect rather than its production. This altered NO signaling pathway is not an early event in insulin resistant individuals. Any such changes will not be apparent until type 2 diabetes with overt hyperglycemia develops.

[Effects of p,p'-DDE on intracellular MAPK pathway of rat Sertoli cells in vitro]

OBJECTIVE

To study effects of p,p'-DDE on intracellular p-ERK of rat Sertoli cells in vitro.

METHODS

We cultured Sertoli cells separated from testicular tissue of rats and examined the changes of intracellular p-ERK, using immunohistochemical SABC method.

RESULTS

It was showed that intracellular p-ERK increased with the dose of p,p'-DDE and had a dose-dependent trend.

CONCLUSION

The results suggested that p,p'-DDE could result in the phosphorylation of ERK and induce the activation of the downstream road and the transcription and expression of genes.

Effects of phenobarbital on metabolism and toxicity of diclofenac sodium in rat hepatocytes in vitro

Diclofenac sodium (DF-Na) was a nonsteroidal anti-inflammatory drug used in various aspects of inflammatory disease. The purpose of this study was to examine the effects of phenobarbital (PB) on metabolism and toxicity of DF-Na in vitro and explore the potential mechanism of DF-Na induced hepatotoxicity. Rat hepatocytes were isolated by a modification of the two-step in situ collagenase perfusion technique and the harvested rat hepatocytes were cultured with sandwich method. Control or PB (2 mM) pre-treated hepatocytes were incubated with DF-Na (0.1, 0.05 or 0.01 mM) in vitro and cytosolic enzyme leakage levels, cytochrome P450 (CYP) 3A activity, and metabolite content of DF-Na in cell culture medium were measured. The results showed that without any treatment hepatocyte CYP 3A activity gradually decreased with culture time. On day four, CYP 3A activity was 53% of the initial value. The decline of CYP 3A was partially reversed by CYP inducer PB, and the maximum induction of CYP 3A was 2.2-fold over control after continuous exposure of hepatocytes to 2 mM PB for 48 h. Lactic dehydrogenase (LDH), aspartate transaminase (AST), and alanine transamine (ALT) activity and the contents of the DF-Na metabolites 4'-hydroxydiclofenac (4'-OH-DF) and 5-hydroxydiclofenac (5-OH-DF) in media appeared to increase with increasing DF-Na concentrations, though there were no significant differences between DF-Na exposed and control hepatocytes. However, if the hepatocytes first were pre-treated with 2 mM PB for 2 days and then exposed to DF-Na, the concentrations of DF-Na metabolites and the activity of LDH in the media were significantly higher than that of control group. These findings suggest that the hepatotoxicity and metabolism of DF-Na in rat hepatocytes are increased when hepatic CYP 3A activity is increased.

[Effects on DNA damage and apoptosis and p53 protein expression induced by fluoride in human embryo hepatocytes]

OBJECTIVE

To study the effects of DNA damage and apoptosis and p53 expression, and to explore the relationship between apoptosis and p53 expression in human embryo hepatocytes induced by fluoride.

METHODS

The rate of DNA damage, apoptosis and the level of p53 expression were investigated after the cells were incubated with sodium fluoride for about 24 hours. The concentrations of sodium fluoride of the control, A, B and C group were 0 microg/ml, 40 microg/ ml, 80 microg/ml and 160 microg/ml individually.

RESULTS

The rate of DNA damage of every group treated with sodium fluoride were significantly higher than the control group (P < 0.05). The percentage of apoptosis of B and C groups increased apparently (P < 0.05). The level of p53 expression of B and C groups were significantly higher than the control group (P < 0.01).

CONCLUSION

Fluoride can increase the rate of DNA damage, and induce apoptosis and expression of p53 in human embryo hepatocytes. Furthermore, both apoptosis and the level of p53 expression, there exists a rise tendency with the increase concentration of fluoride.

Polymorphism of the immune-braking gene CTLA-4 (+49) involved in gender discrepancy of serum total IgE levels and allergic diseases

BACKGROUND

A variety of genes are related to allergic disorders in different ethnic populations. The genetic basis for the gender discrepancy of allergic diseases remains to be determined.

OBJECTIVE

This study was conducted to investigate whether IL-4 promoter (-590 C/T) and cytotoxic T lymphocyte antigen 4 (CTLA-4) (+49 A/G) polymorphisms were correlated with a gender discrepancy of total IgE levels and allergic diseases in a Chinese population.

METHODS

A total of 1333 participants aged 19-49 years were enrolled in this study. Allergic diseases were recognized by the presence of asthma, rhinitis or atopic dermatitis in conjunction with detectable specific IgE in the blood. Polymorphisms of IL-4 promoter (-590) and CTLA-4 (+49) were determined by restriction fragment length polymorphism.

RESULTS

Males or females with allergic diseases had higher total IgE levels than those without (P=0.000). Females with the A/A genotype in the CTLA-4 (+49) position had significantly higher total IgE levels than those with A/G, and those with the G/G genotype had the lowest IgE levels (154.9 vs. 107.1 vs. 79.8 KU/L; mean log values: 1.79 vs. 1.65 vs. 1.54, P< 0.001). However, males with different genotypes in the CTLA-4 (+49) position exhibited no difference in the total IgE levels. Females with allergic rhinitis had a significantly higher frequency of the A/A genotype in the CTLA-4 (+49) polymorphism than those without atopic diseases (P=0.016). In contrast, males with and without allergic disorders exhibited no significant difference in the CTLA-4 (+49) polymorphisms (P>0.05). The IL-4 promoter (-590) polymorphisms, however, had no correlation with the total IgE levels or allergic diseases in either females or males.

CONCLUSION

In females only, the CTLA-4 (+49), but not the IL-4 promoter (-590), polymorphism was significantly associated with elevation of total IgE levels and allergic rhinitis. Here, we have, for the first time, demonstrated a gender-linked genetic relationship with allergic disease.

[Studies on purification of polyprenol from Ginkgo biloba L. leaves]

OBJECTIVE

To research the methods of purifying polyprenol from leaves of Ginkgo biloba L..

METHODS

The purity of polyprenol was determined by HPLC to select the optimal purifying conditions.

RESULTS

The optimal conditions were degreased by 160 times of petroleum ether-ethyl acetate (9:1) firstly, then through a silica gel column (100-140 mesh) and eluted with petroleum etherethyl acetate (19:1).

CONCLUSION

The methods are feasible to purify polyprenol from leaves of Ginkgo biloba L. and could increase the purity of polyprenol obviously.

[Study on the production condition of extraction in combination hydrolysis in situ for isolating diosgenin]

OBJECTIVE

To study the production technology of extraction in combination hydrolysis in situ for isolating diosgenin from Dioscorea nipponica by orthogonal design.

METHOD

The optimum production conditions were investigated with the recovery of diosgenin as an index by extraction in combination hydrolysis in situ, and were compared with the traditional method.

RESULT

Extraction in combination hydrolysis in situ conducted in 1.5 mol x L(-1) sulfuric acid of water containing 75% isopropanol at 100 degrees C for 4.5 h could get higher recovery of diosgenin than traditional methods.

CONCLUSION

This production technology can get higher recovery of diosgenin, and it is simple, time and money saving.

[Isolation and HPLC analysis of ginkgolic acid]

OBJECTIVE

To isolate ginkgolic acids (GA) from exopleura of Ginkgo biloba and to analyse GA.

METHODS

GA were ultrasonic-extracted from exopleura of Ginkgo biloba with petroleum ether, and purified by silica gel column chromatography. The content of GA in sample was determined by HPLC with methanol-3% acetic acid (90:10) as mobile phase at a flow rate of 1 ml/min. UV detection wavelength was set at 310 nm. A HiQ sil C18 column was used at 40 degrees C in analysis.

RESULTS

A good linearity was obtained in the range of 1.144-5.720 micrograms (r = 0.9978) for GA. The average recovery of GA was 97.50% with RSD of 1.70%.

CONCLUSION

The method may be employed to prepare GA from exopleura of Ginkgo biloba. The analysis method for GA is accurate and reliable, and can be used for determination of GA in sample.