[Impact of bicuspid aortic valve or tricuspid aortic valve on hemodynamics and left ventricular reverse remodeling in patients after transcatheter aortic valve replacement].

Objective: To compare the impact of bicuspid aortic valve (BAV) or tricuspid aortic valve (TAV) on hemodynamics and left ventricular reverse remodeling after transcatheter aortic valve replacement (TAVR). Methods: We retrospectively analyzed the clinical data of patients who underwent TAVR in our hospital from January 2019 to March 2021. Patients were divided into BAV group and TAV group according to aortic contrast-enhanced CT. Each patient was followed up by N-terminal pro B-type natriuretic peptide (NT-proBNP) and echocardiography at four time points, namely before TAVR, 24 hours, 1 month and 6 months after TAVR. Echocardiographic data, including mean pressure gradient (MPG), aortic valve area (AVA), left ventricular ejection fraction (LVEF), left ventricle mass (LVM) and LV mass index (LVMi) were evaluated. Results: A total of 41 patients were included. The age was (75.0±8.6) years, and male patients accounted for 53.7%. There were 19 BAV patients and 22 TAV patients in this cohort. All patients undergoing TAVR using a self-expandable prosthesis Venus-A valve. MPG was (54.16±21.22) mmHg(1 mmHg=0.133 kPa) before TAVR, (21.11±9.04) mmHg at 24 hours after TAVR, (18.84±7.37) mmHg at 1 month after TAVR, (17.68±6.04) mmHg at 6 months after TAVR in BAV group. LVEF was (50.42±13.30)% before TAVR, (53.84±10.59)% at 24 hours after TAVR, (55.68±8.71)% at 1 month after TAVR and (57.42±7.78)% at 6 months after TAVR in BAV group. MPG and LVEF substantially improved at each time point after operation, and the difference was statistically significant (all P<0.05) in BAV group. MPG in TAV group improved at each time point after operation, and the difference was statistically significant (all P<0.05). LVMi was (164.13±49.53), (156.37±39.11), (146.65±38.84) and (134.13±39.83) g/m2 at the 4 time points and the value was significantly reduced at 1 and 6 months post TAVR compared to preoperative level(both P<0.05). LVEF in the TAV group remained unchanged at 24 hours after operation, but it was improved at 1 month and 6 months after operation, and the difference was statistically significant (all P<0.05). LVMi in TAV group substantially improved at each time point after operation, and the difference was statistically significant (all P<0.05). NT-proBNP in both two groups improved after operation, at 1 month and 6 months after operation, and the difference was statistically significant (all P<0.05). MPG in TAV group improved better than in BAV group during the postoperative follow-up (24 hours after TAVR: (11.68±5.09) mmHg vs. (21.11±9.04) mmHg, P<0.001, 1 month after TAVR: (10.82±3.71) mmHg vs. (18.84±7.37) mmHg, P<0.001, 6 months after TAVR: (12.36±4.42) mmHg vs. (17.68±6.04) mmHg, P=0.003). There was no significant difference in NT-proBNP between BAV group and TAV group at each time point after operation (all P>0.05). There was no significant difference in paravalvular regurgitation and second prosthesis implantation between the two groups (all P>0.05). Conclusions: AS patients with BAV or TAV experience hemodynamic improvement and obvious left ventricular reverse remodeling after TAVR, and the therapeutic effects of TAVR are similar between BAV and TAV AS patients in the short-term post TAVR.

Blockade of fatty acid signalling inhibits lipopolysaccharide-induced macrophage recruitment and progression of apical periodontitis.

AIM: To examine the role of palmitic acid in lipopolysaccharide (LPS)-stimulated chemotaxis of macrophages and the potential contribution of saturated fatty acid in signalling during the pathogenesis of apical periodontitis. METHODOLOGY: J774, a mouse macrophage cell line, was used in the experiments. After treatment with LPS, proteolytic maturation of sterol regulatory element-binding protein-1c (SREBP-1c) and expression of fatty acid synthase (FASN) were examined by Western analysis. Levels of palmitic acid were measured by reverse phase-high performance liquid chromatography-mass spectrometry. Knockdown of SREBP-1c and FASN was accomplished by small interfering RNA technology. Secretion of CC-chemokine ligand 2 (CCL2) and cellular chemotaxis were assessed by enzyme-linked immunosorbent assay and transwell migration assay, respectively. Sulfo-N-succinimidyl oleate (SSO) treatment was used to inhibit fatty acid signalling in vitro and also in a rat model of apical periodontitis. All data were first subjected to Levene's test. In vitro data were then analysed using ANOVA followed by Tukey's multiple comparison test. Data from animal experiments were analysed by independent t-tests. The significant level was set at 0.05. RESULTS: LPS stimulated proteolytic maturation of SREBP-1c and FASN expression in macrophages and significantly enhanced palmitic acid synthesis (P < 0.05). Knockdown of SREBP-1c attenuated LPS-enhanced FASN expression. Knockdown of FASN significantly suppressed LPS-enhanced palmitic acid synthesis (P < 0.05). LPS and exogenous palmitic acid significantly enhanced CCL2 secretion and macrophage chemotaxis (all P < 0.05). Inhibition of FASN expression significantly alleviated LPS-augmented CCL2 secretion (P < 0.05). SSO significantly suppressed CCL2 secretion and macrophage chemotaxis augmented by LPS and palmitic acid (all P < 0.05). In a rat model of induced apical periodontitis, SSO treatment significantly attenuated progression of apical periodontitis and macrophage recruitment (all P < 0.05). CONCLUSIONS: LPS/SREBP-1c/FASN/palmitic acid signalling contributed to tissue destruction caused by bacterial infection. Modulation of lipid metabolism and signalling may be helpful for the management of apical periodontitis.

[Application of indocyanine green-fluorescent imaging technique in planning resection line and real-time surgical navigation in small hepatocellular carcinoma].

Objective: To explore the value of near-infrared technology guided by indolecyanine green(ICG) in planning resection line and real-time surgical navigation in small liver cancer. Methods: From March to September 2015, 11 patients with hepatic tumors received hepatectomy were treated in First Department of Hepatobiliary Surgery, Zhujiang Hospital, Southern Medical University.There were 5 male and 6 female patients with average age of (55±10)years (range 39-70 years). Among whom, there were 9 cases with hepatocellular carcinoma and 2 cases with colorectal cancer. A near-infrared light camera system was used to detect the liver surfaces before resection, and to plan resection line and surgical specimens. A student's t test was used to compare continuous parametric variables. Results: The ICG-fluorescent imaging and histological examination had been used in the 15 lesions of the 11 patients. Among the 15 lesions, 7 lesions were detected by visual inspections, palpation and ICG-fluorescent imaging, 6 lesions were identified only by ICG-fluorescent imaging, 2 lesions were detected only by ICG-fluorescent imaging after resection.Results of pathologic examination indicated that the total fluorescent type include 5 well differentiated hepatocellular carcinoma and 2 cirrhotic nodule; the partial fluorescent type include 3 moderately differentiated hepatocellular carcinomas and 1 well differentiated hepatocellular carcinomas; the rim fluorescent type included 2 liver metastatic carcinoma and 2 poorly differentiated hepatocellular carcinomas. The average diameter of the tumor size measured by CT was (1.7±0.2)cm, while the average diameter measured by ICG-fluorescent imaging was (1.7±0.3)cm(t=-0.188, P>0.05). Conclusion: Near-infrared technology guided by ICG has important value in planning resection line and real-time surgical navigation in small liver cancer.

Fatigue life enhancement of NiTi rotary endodontic instruments by progressive reciprocating operation.

AIM: To evaluate the effect of reciprocating amplitude and progressive angular increment on fatigue life enhancement of NiTi rotary endodontic instruments. METHODOLOGY: ProTaper F2 instruments were operated in steel artificial canals with both stationary reciprocating (SR) and progressive reciprocating (PR) motions. The SR motions involved symmetric to and fro reciprocation of ± 180(o) , ± 135(o) , ± 90(o) , ± 60(o) and ± 45(o) . The PR motions were ± 45(o) stationary motion superimposed with angular increments of 7(o) , 11(o) , 22.5(o) or 31(o) whenever an instrument completed 1, 10 or 30 reciprocating cycles (rc). The fatigue lives were compared with those under continuous rotation (CR) and a reciprocating operation with a forward 144(o) and backward 72(o) motion proposed by Yared (2008). The statistical significance of these operating modes on fatigue life was examined using one way anova and post hoc Tukey's tests at P = 0.05. Fractographic analysis was also applied to probe the fracture mechanisms of different rotation motions. RESULTS: Fatigue life increased with decreasing reciprocating amplitude. Operating in the SR increased fatigue life by 355% over that in the CR. Except for the 22.5(o) increment, all PR motions yielded longer fatigue lives than the SR motion. A progressive reciprocating operation with a ± 45(o) reciprocating amplitude and a + 7(o) progressive angular increment every 10 reciprocating cycles (± 45(o) /10rc/+7(o) ) increased fatigue life by 990% over that in the CR motion. In terms of life enhancement over the CR motion, the larger the curvature the less are the differences between different movements. Single crack initiation sites were found in the CR and SR motions, while three crack initiation sites were typical in the ± 45(o) /10rc/+7(o) motion. CONCLUSIONS: Fatigue life increased with decreasing reciprocating amplitude in stationary reciprocation. A progressive reciprocating operation with ± 45(o) /10rc/+7(o) motion led to significant fatigue life enhancement and multiple fatigue crack initiation in NiTi endodontic instruments.

Catechin stimulates osteogenesis by enhancing PP2A activity in human mesenchymal stem cells.

SUMMARY: Using human mesenchymal stem cells, we identified catechin from a panel of herbal ingredients and Chinese traditional compounds with the strongest osteogenic effects. Catechin increased alkaline phosphatase activity, calcium deposition, and mRNA expression of Runx2 and osteocalcin. We further clarified the signaling pathway that catechin mediated to stimulate osteogenesis. INTRODUCTION: Human mesenchymal stem cells (hMSCs), useful as a species specific cell culture system for studying cell lineage differentiation, were examined as a tool to identify novel herbal ingredients and Chinese traditional compounds for enhancing osteogenesis. METHODS: Immortalized and primary hMSCs were induced in osteogenic induction medium in the presence of a variety of herbal ingredients and Chinese traditional compounds and osteogenic differentiation was evaluated by histochemical assays and quantitative RT-PCR. RESULTS: Using immortalized hMSCs, we first identified catechin, 18ß-glycyrrhetinic acid, baishao, and danggui with osteogenic properties, which enhanced calcium deposition at the dose without significant cytotoxic effects. Primary hMSCs were then applied for confirming the osteogenic effects of catechin, which increased alkaline phosphatase activity, calcium deposition, and mRNA expression of Runx2 and osteocalcin. We further found the extracellular signal-regulated kinase (ERK) pathway was downregulated upon stimulation with catechin. Catechin increased the level and activity of protein phosphatases 2A (PP2A) that dephosphorylates ERK kinase (MEK) and ERK. Further, PP2A inhibitor, okadaic acid, abolished the effect of catechin-mediated inactivation of ERK and stimulation of osteogenesis. The blocking effect of okadaic acid on osteogenesis was further reversed by PD98059, a specific inhibitor of MEK. Co-immunoprecipitation revealed the association of PP2A to both MEK and ERK. CONCLUSIONS: These studies propose catechin enhanced osteogenesis by increasing the PP2A level that inhibits the MEK and ERK signaling in hMSCs. These results prove the concept of using hMSCs as a convenient tool for rapid and consistent screening of the osteogenic herbal ingredients and traditional Chinese compounds.

Mitochondrial dysfunction-induced amphiregulin upregulation mediates chemo-resistance and cell migration in HepG2 cells.

The aim of this study was to investigate the contribution of mitochondrial dysfunction to chemoresistance and migration of hepatoma cells. We found that inhibition of mitochondrial respiration and mitochondrial DNA (mtDNA) depletion resulted in induction of amphiregulin (AR) expression in HepG2 cells. Upon oligomycin treatment of HepG2 cells, the cytosolic Ca(2+) was significantly raised after 30 min, and the intracellular level of reactive oxygen species (ROS) was elevated 2.2-fold after 4 h. Moreover, the condition medium of oligomycin-treated HepG2 cells was found to stimulate the migration of SK-Hep-1 cells. On the other hand, oligomycin-induced cisplatin-resistance and cell migration of HepG2 cells were attenuated by AR-specific RNA interference (#L-017435, Dharmacon) and a neutralizing antibody (MAB262, R&D Systems), respectively. Together, these findings suggest that mitochondrial dysfunction induced Ca(2+) mobilization, and ROS overproduction, which modulated the chemo-resistance and migration of hepatoma cells through the induction and activation of AR.

Overexpression of NBS1 induces epithelial-mesenchymal transition and co-expression of NBS1 and Snail predicts metastasis of head and neck cancer.

Major causes of head and neck squamous cell carcinoma (HNSCC)-related deaths are cervical node and distant metastasis. We previously demonstrated that overexpression of the DNA double-strand break repair protein Nijmegen breakage syndrome 1 (NBS1) is a prognostic marker of advanced HNSCCs. Epithelial-mesenchymal transition (EMT) was demonstrated to be the major mechanism responsible for mediating invasiveness and metastasis of late-stage cancers. We therefore investigated the role of NBS1 overexpression in mediating EMT and metastasis. NBS1 overexpression was associated with metastasis of HNSCC patients using tissue microarray-immunohistochemistry approach. Induction of EMT was observed in an NBS1-overexpressing HNSCC cell line (FADUNBS), whereas short-interference RNA (siRNA)-mediated repression of endogenous NBS1 reversed the shift of EMT markers. Increased migration/invasiveness of FADUNBS was shown by in vitro and in vivo assays. NBS1 overexpression upregulated the expression of an EMT regulator Snail and its downstream target matrix metalloproteinase-2. EMT phenotypes and increased migration/invasiveness of FADUNBS cells were reversed by siRNA-mediated repression of Snail expression or a phosphatidylinositol 3-kinase-specific inhibitor. In HNSCC samples, co-expression of NBS1/Snail in primary tumors correlated with metastasis and the worst prognosis. These results indicate that NBS1 overexpression induces EMT through the upregulation of Snail expression, and co-expression of NBS1/Snail predicts metastasis in HNSCCs.

Iron-generated hydroxyl radicals kill retinal cells in vivo: effect of ferulic acid.

Siderosis bulbi is vision threatening. An investigation into its mechanisms and management is crucial. Experimental siderosis was established by intravitreous administration of an iron particle (chronic) or FeSO(4) (acute). After siderosis, there was a significant dose-responsive reduction in eletroretinogram (a/b-wave) amplitude, and an increase in OH level, greater when caused by 24 mM FeSO(4) than that by 8 mM FeSO(4). Furthermore, the FeSO(4)-induced oxidative stress was significantly blunted by 100 microM ferulic acid (FA). Siderosis also resulted in an excessive glutamate release, increased [Ca(++)](i), and enhanced superoxide dismutase immunoreactivity. The latter finding was consistent with the Western blot result. Obvious disorganization including loss of photoreceptor outer segments and cholinergic amacrines together with a wide-spreading ferric distribution across the retina was present, which were related to the eletro-retinographic and pathologic dysfunctions. Furthermore, b-wave reduction and amacrine damage were respectively, significantly, dose-dependently, and clearly ameliorated by FA. Thus, siderosis stimulates oxidative stress, and possibly, subsequent excitotoxicity, and calcium influx, which explains why the retina is impaired electro-physiologically and pathologically. Importantly, FA protects iron toxicity perhaps by acting as a free radical scavenger. This provides an approach to the study and treatment of the iron-related disorders such as retained intraocular iron and Alzheimer disease.

DDX3, a DEAD box RNA helicase, is deregulated in hepatitis virus-associated hepatocellular carcinoma and is involved in cell growth control.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer deaths worldwide and is highly correlated with hepatitis virus infection. Our previous report shows that a DEAD box RNA helicase, DDX3, is targeted and regulated by hepatitis C virus (HCV) core protein, which implicates the involvement of DDX3 in HCV-related HCC development. In this study, the potential role of DDX3 in hepatocarcinogenesis is investigated by examining its expression in surgically excised human HCC specimens. Here we report the differential deregulation of DDX3 expression in hepatitis virus-associated HCC. A significant downregulation of DDX3 expression is found in HCCs from hepatitis B virus (HBV)-positive patients, but not from HCV-positive ones, compared to the corresponding nontumor tissues. The expression of DDX3 is differentially regulated by the gender and, moreover, there is a tendency that the downregulation of DDX3 expression in HCCs is more frequent in males than in females. Genetic knockdown of DDX3 with small interfering RNAs (siRNA) in a nontransformed mouse fibroblast cell line, NIH-3T3, results in a premature entry to S phase and an enhancement of cell growth. This enhanced cell cycle progression is linked to the upregulation of cyclin D1 and the downregulation of p21(WAF1) in the DDX3 knockdown cells. In addition, constitutive reduction of DDX3 expression increases the resistance of NIH-3T3 cells to serum depletion-induced apoptosis and enhances the ras-induced anchorage-independent growth, indicating the involvement of DDX3 in cell growth control. These findings together with the previous study suggest that the deregulation of DDX3, a DEAD box RNA helicase with cell growth-regulatory functions, is involved in HBV- and HCV-associated pathogenesis.

Evaluation of interleukin-6, interleukin-10 and human hepatocyte growth factor as tumor markers for hepatocellular carcinoma.

AIM: Serum alpha-fetoprotein (AFP) is the most important tumor marker for hepatocellular carcinoma (HCC). Previous reports indicated that HCC was also associated with increased levels of interleukin (IL)-6, IL-10 and hepatocyte growth factor (HGF). This study investigated the role of these cytokines as tumor markers for HCC. METHOD: A total of 128 adults were prospectively enrolled and categorized into four groups: normal subjects (n=29), chronic hepatitis B or C (n=50), non-HCC tumors (n=23) and HCC (n=26). Serum AFP, IL-6, IL-10 and HGF levels were determined in all subjects. RESULTS: The expression of IL-6 or IL-10 (> or =3 pg/ml), or high level of HGF (>1000 pg/ml) or AFP (>20 ng/ml) was observed in only 0-3% of normal subjects. Patients with HCC more frequently had higher IL-6 and IL-10 levels (p<0.05), whereas HGF levels in HCC patients were not significantly elevated compared to patients with chronic hepatitis or non-HCC tumors. Among patients with low (<20 ng/ml) AFP level, IL-6 or IL-10 expression was significantly associated with the existence of HCC (p<0.05). Patients with large (>5 cm) HCC more often had increased IL-6, IL-10 or AFP levels (p values all <0.05). CONCLUSIONS: Serum levels of IL-6 and IL-10 are frequently elevated in patients with HCC but not in benign liver disease or non-HCC tumors. IL-6 and IL-10 may help identify a subset of HCC patients with low AFP level, and may serve as complementary tumor markers in these patients.

Combined therapy with 5-azacytidine and hydrocortisone in glucocorticoid-sensitive and -resistant mouse P1798 lymphosarcoma.

Experiments were undertaken to test the hypothesis that 5-azacytidine (AZA) treatment might make the glucocorticoid-resistant line of the mouse P1798 lymphosarcoma sensitive to cortisol. A modest (30%), though significant, effect in making cells cortisol sensitive was observed. Moreover, AZA enhanced tumor growth inhibition by cortisol in the corresponding sensitive line. The AZA alone was cytostatic, but it had no effect on DNA synthesis. The drug did not alter cytoplasmic glucocorticoid receptor levels or affinity, but nuclear levels were increased in the sensitive tumor. Results suggest that glucocorticoid resistance may be partially reversible and that the effect of AZA may be at the gene-expression level.

Correlation of hepatocyte growth factor-induced proliferation and calcium-activated potassium current in human gastric cancer cells.

Hepatocyte growth factor (HGF) has been found to stimulate proliferation and migration of human gastric carcinoma cells. Whether the HGF-induced responses are correlated with the expressed level of HGF receptors or the changes of ionic currents is not clear. The present study investigated the effects of HGF on the proliferation and ionic currents of two human gastric adenocarcinoma cell lines, which were found to express different amounts of HGF receptor. Results showed that HGF induced a dose-dependent growth stimulation and accelerated cell cycle progression in SC-M1 cells. In patch clamp study, HGF treatment induced an outward K+ current and increased the slope conductance at -80 mV from 110+/-15 pS/pF to 207+/-15 pS/pF. The HGF-induced K+ current was abolished when tetraethylammonium chloride was added in bathing solution or a low Ca2+ solution was included in the recording pipette. Furthermore, HGF (10 ng/ml) induced an oscillatory Ca2+-activated K+ current with a lag period of 5+/-3 min in SC-M1 cells. In contrast, HGF did not induce mitogenesis, cell cycle progression and changes in ionic currents in KATO-III cells, although this cell line expressed a higher level of HGF receptors than SC-M1 cells did. These findings provide evidence that the activity of Ca2+-activated K+ channel may be involved in the HGF-induced cell proliferation in human gastric cancer cells, but it did not correlate with the density of HGF receptors.

Purification and preliminary characterization of new peptide inhibitor of insulin from pork pancreas.

A new active peptide was purified from the acid-alcohol extract of pork pancreas. It markedly suppressed the insulin activity detected by either in vivo mouse convulsion assay or in vitro free-fat cell assay. When the extract was subjected to chromatography on a carboxymethylcellulose column, the insulin fraction completely passed through the column, whereas the glucagon fraction was absorbed. The fact that the total apparent biological activity of insulin in the exclusive eluate was higher than in the original extract and the insulin radioimmunoactivity remained unchanged led to the discovery of a potent insulin inhibitor in the extract. The inhibitor was separated from glucagon and insulin in the extract by ion-exchange chromatography on a carboxymethylcellulose column followed by gel filtration on a Bio-Gel P-6 column and finally purified by reverse-phase high-performance liquid chromatography (HPLC) on a C-18 column. The antagonistic effect of this inhibitor on insulin was dose dependent with an ED50 of 2 x 10(-10) M, which was the same level used for insulin in vitro assay (1.7 x 10(-10) M). Amino acid analysis of the inhibitor showed that it was rich in arginine and glycine. It was estimated to be approximately 3000 Mr. The NH2-terminal of the peptide was proved to be blocked because it could not be degraded by Edman degradation. Based on the physicochemical and biochemical characteristics of the inhibitor and compared with other active peptides known to be in the pancreas, the inhibitor is probably a new active peptide that might play an important role in homeostasis of carbohydrate metabolism.

tie-1 protein tyrosine kinase: a novel independent prognostic marker for gastric cancer.

Protein tyrosine kinases (PTKs) are a major class of proto-oncogenes that are involved in tumor progression. The purpose of this study was to establish a comprehensive PTK expression profile in gastric cancers, with the objective of identifying possible biomarkers for gastric cancer progression. We have designed degenerate primers according to the consensus catalytic motifs to amplify PTK molecules from gastric cancers by reverse transcriptase-PCR methods. The PTK expression profile was established by sequencing analysis of the cloned PCR products. We have identified 17 PTKs from a gastric adenocarcinoma. Two receptor PTKs, tie-1 and axl, were selected for in situ immunohistochemistry studies because of their higher expression level and their described roles in adhesion, invasion, and angiogenesis. Among the 97 gastric adenocarcinoma tissues examined, we observed positive immunohistochemical staining of tie-1 PTK in 69 and positive staining of axl kinase in 71 tissues. Statistical analysis with clinicopathological features indicates that tie-1 kinase expression is inversely correlated with patients' survival, whereas axl fails to show similar clinical significance. Our results illustrate the utility of tyrosine kinase gene family profiling in human gastric cancers and show that tie-1 tyrosine kinase may serve as a novel independent prognostic marker for gastric adenocarcinoma patients.

High frequency of rearrangement of the RET protooncogene (RET/PTC) in Chinese papillary thyroid carcinomas.

The activation of RET protooncogene, through chromosomal translocation, is unique to papillary thyroid carcinomas. Rearrangement of the RET kinase domain to 3 partner genes has been described, of which the RET/PTC1 is the most common. To investigate the frequency of RET rearrangement in Chinese papillary thyroid carcinomas, we have performed RT-PCR to amplify specific RET/PTC transcripts. Among the papillary thyroid carcinomas of 11 patients examined, we have identified 2 containing RET/PTC1, 3 containing RET/PTC2, and 1 containing RET/PTC3 oncogenes. Although the cause of the high frequency of RET/PTC oncogenes in Chinese papillary thyroid carcinomas is unknown, our study suggests that RET rearrangement is an important genetic lesion underlying the development of thyroid papillary carcinoma in Taiwan.

Genomic organization of three neurotoxins active on small conductance Ca2+-activated potassium channels from the scorpion Buthus martensi Karsch.

According to the known primary sequences of three neurotoxins active on small conductance Ca2+-activated potassium channels from the scorpion Buthus martensi Karsch, their corresponding cDNAs were cloned and sequenced using 3'- and 5'-RACE. All of them encoded a signal peptide composed of 28 residues and a mature toxin of 29, 28 and 33 residues, respectively. Their cDNA deduced sequences were totally consistent with those determined, and the C-terminal amidation of one neurotoxin was confirmed. The genomic DNAs of these three toxins were also amplified by PCR, cloned and sequenced. They all consisted of two exons disrupted by a small single intron. All of these introns were inserted within the signal peptide at the same -10 position upstream from the mature toxin, consisting of 94, 78 and 87 bp, respectively.

Epsilon 4 allele of apolipoprotein E increases risk of Alzheimer's disease in a Chinese population.

We examined the apolipoprotein E genotype in 56 Chinese patients with late-onset sporadic Alzheimer's disease (AD) and 57 Chinese control subjects of similar age. The frequency of epsilon 4 in the AD group was significantly higher than that in the control group (23.2% versus 7.9%, p = 0.003). The odds ratio for AD in individuals with either one or two epsilon 4 was 2.96 (95% CI 1.11 to 8.03). The linear trend for AD in proportion to alleles of epsilon 4 was also significant (chi 2 = 8.2, p = 0.004). Our results support the association between epsilon 4 and AD in the Chinese.

Enhanced hydroxychavicol-induced cytotoxic effects in glutathione-depleted HepG2 cells.

Hydroxychavicol (HC) is the major safrole urinary metabolite in rats and humans. The cytotoxic potential of HC in metabolically competent cells has yet to be studied. HC alone was slightly toxic to HepG2 cells. However, the cytotoxicity increased significantly (P<0.05) when HepG2 cells were pretreated with buthionine sulfoximine (BSO), suggesting that endogenous glutathione participates in HC-induced cytotoxicity. Addition of catalase or N-acetylcysteine prevented the BSO plus HC-mediated cytotoxicity. HC also increased 8-hydroxy-2'-deoxyguanosine formation and apoptosis in BSO-pretreated HepG2 cells and this increase could also be suppressed by catalase. These data suggest that BSO pretreatment enhanced HC-induced cytotoxic effects in HepG2 cells, which are related to oxidative DNA damage.

Mechanistic study of the inhibition of aflatoxin b1-induced hepatotoxicity by dimethyl 4,4'-dimethoxy-5,6,5',6'-dimethylenedioxy biphenyl-2, 2'-dicarboxylate.

The mechanism of DDB (dimethyl 4,4'-dimethoxy-5,6,5',6'-dimethylenedioxy biphenyl-2,2'-dicarboxylate) prevention of aflatoxin B1 (AFB1)-induced hepatotoxicity in rats has been investigated. Pretreatment of DDB (200 mg/kg) daily for 4 days significantly suppressed (P < 0.05) the AFB1-induced hepatic damage as evidenced by the increase of serum marker enzymes. DDB induced rat hepatic cytochrome P450IA1, IIB1 and glutathione S-transferase activities. The hepatic microsomes derived from DDB treated rats increased the mutation frequency of AFB1 and enhanced the binding of AFB1 to DNA. However, the hepatic S9 fraction from DDB treated rats showed a protective effect against AFB1-induced damage. It is concluded that the protective effect of DDB against AFB1-induced damage might be mediated by the induced glutathione S-transferase activity and not from the accelerated hepatic cytochrome P450 detoxification pathway of AFB1 which was previously believed.

Non-destructive analysis of the protein conformational structure of human pituitary adenomas using reflectance FT-IR microspectroscopy.

Reflectance Fourier-transform infrared microspectroscopy was used to determine the secondary structure and composition of the different human pituitary adenomas. Non-functioning pituitary adenomas exhibited similar protein secondary structure and conformational composition, but active pituitary adenomas revealed different behavior. The differences in secondary structure for the different human pituitary adenomas might possibly be due to the different protein conformations of the proliferated adenoma tissues and various hormones shared.