Evaluation of fecal microbiomes associated with obesity in captive cynomolgus monkeys (Macaca fascicularis)

Microorganisms play important roles in obesity; however, the role of the gut microbiomes in obesity is controversial because of the inconsistent findings. This study investigated the gut microbiome communities in obese and lean groups of captive healthy cynomolgus monkeys reared under strict identical environmental conditions, including their diet. No significant differences in the relative abundance of Firmicutes, Bacteroidetes and Prevotella were observed between the obese and lean groups, but a significant difference in Spirochetes (p < 0.05) was noted. Microbial diversity and richness were similar, but highly variable results in microbial composition, diversity, and richness were observed in individuals, irrespective of their state of obesity. Distinct clustering between the groups was not observed by principal coordinate analysis using an unweighted pair group method. Higher sharedness values (95.81% ± 2.28% at the genus level, and 79.54% ± 5.88% at the species level) were identified among individual monkeys. This paper reports the association between the gut microbiome and obesity in captive non-human primate models reared under controlled environments. The relative proportion of Firmicutes and Bacteroidetes as well as the microbial diversity known to affect obesity were similar in the obese and lean groups of monkeys reared under identical conditions. Therefore, obesity-associated microbial changes reported previously appear to be associated directly with environmental factors, particularly diet, rather than obesity.

A Novel Collateral Imaging Method Derived from Time-Resolved Dynamic Contrast-Enhanced MR Angiography in Acute Ischemic Stroke: A Pilot Study

BACKGROUND AND PURPOSE

Assessment of the collateral status has been emphasized for appropriate treatment decisions in patients with acute ischemic stroke. The purpose of this study was to introduce a multiphase MRA collateral imaging method (collateral map) derived from time-resolved dynamic contrast-enhanced MRA and to verify the value of the multiphase MRA collateral map in acute ischemic stroke by comparing it with the multiphase collateral imaging method (MRP collateral map) derived from dynamic susceptibility contrast-enhanced MR perfusion.

MATERIALS AND METHODS

From a prospectively maintained registry of acute ischemic stroke, MR imaging data of patients with acute ischemic stroke caused by steno-occlusive lesions of the unilateral ICA and/or the M1 segment of the MCA were analyzed. We generated collateral maps using dynamic signals from dynamic contrast-enhanced MRA and DSC-MRP using a Matlab-based in-house program and graded the collateral scores of the multiphase MRA collateral map and the MRP collateral map independently. Interobserver reliabilities and intermethod agreement between both collateral maps for collateral grading were tested.

RESULTS

Seventy-one paired multiphase MRA and MRP collateral maps from 67 patients were analyzed. The interobserver reliabilities for collateral grading using multiphase MRA or MRP collateral maps were excellent (weighted κ = 0.964 and 0.956, respectively). The agreement between both collateral maps was also excellent (weighted κ = 0.884; 95% confidence interval, 0.819-0.949).

CONCLUSIONS

We demonstrated that the dynamic signals of dynamic contrast-enhanced MRA could be used to generate multiphase collateral images and showed the possibility of the multiphase MRA collateral map as a useful collateral imaging method in acute ischemic stroke.

Influence of Local Myocardial Infarction on Endothelial Function, Neointimal Progression, and Inflammation in Target and Non-Target Vascular Territories in a Porcine Model of Acute Myocardial Infarction

BACKGROUND

Patients with acute myocardial infarction (AMI) have worse clinical outcomes than those with stable coronary artery disease despite revascularization. Non-culprit lesions of AMI also involve more adverse cardiovascular events. This study aimed to investigate the influence of AMI on endothelial function, neointimal progression, and inflammation in target and non-target vessels.

METHODS

In castrated male pigs, AMI was induced by balloon occlusion and reperfusion into the left anterior descending artery (LAD). Everolimus-eluting stents (EES) were implanted in the LAD and left circumflex (LCX) artery 2 days after AMI induction. In the control group, EES were implanted in the LAD and LCX in a similar fashion without AMI induction. Endothelial function was assessed using acetylcholine infusion before enrollment, after the AMI or sham operation, and at 1 month follow-up. A histological examination was conducted 1 month after stenting.

RESULTS

A total of 10 pigs implanted with 20 EES in the LAD and LCX were included. Significant paradoxical vasoconstriction was assessed after acetylcholine challenge in the AMI group compared with the control group. In the histologic analysis, the AMI group showed a larger neointimal area and larger area of stenosis than the control group after EES implantation. Peri-strut inflammation and fibrin formation were significant in the AMI group without differences in injury score. The non-target vessel of the AMI also showed similar findings to the target vessel compared with the control group.

CONCLUSION

In the pig model, AMI events induced endothelial dysfunction, inflammation, and neointimal progression in the target and non-target vessels.

Sarcopenia is associated with the risk of significant liver fibrosis in metabolically unhealthy subjects with chronic hepatitis B

BACKGROUND

Sarcopenia is significantly associated with the degree of liver fibrosis. This study investigated the influence of sarcopenia on liver fibrosis in individuals with chronic hepatitis B.

METHODS

Data from the Korean National Health and Nutrition Examination Surveys 2008-2011 were analysed. The sarcopenia index (total appendicular skeletal muscle mass [kg]/body mass index [kg/m² ]) was calculated using dual-energy X-ray absorptiometry. Sarcopenia was defined as the lowest quintile sarcopenia index value (cut-offs: 0.89 for men and 0.58 for women). The fibrotic burden was assessed using the nonalcoholic fatty liver disease fibrosis score and fibrosis-4 index. Significant fibrosis was defined as the highest nonalcoholic fatty liver disease fibrosis score quartile and a fibrosis-4 index ≥2.67.

RESULTS

Among the 506 respondents with chronic hepatitis B (258 men and 248 women), the nonalcoholic fatty liver disease fibrosis score and fibrosis-4 index identified sarcopenia and significant fibrosis in 126 (24.9%) and 217 (42.9%), respectively. Sarcopenia was significantly associated with significant fibrosis, regardless of the fibrosis prediction model used (all P < 0.05). When the study population was stratified according to metabolic factors, sarcopenia was specifically associated with an increased risk of significant fibrosis among subgroups with obesity, insulin resistance, metabolic syndrome and liver steatosis (odds ratio 2.37-3.57; all P < 0.05). An independent association between sarcopenia and significant fibrosis was identified after adjusting for other confounders (odds ratio 2.67-3.62 by the nonalcoholic fatty liver disease fibrosis score and 2.04-2.62 by the fibrosis-4 index; all P < 0.05).

CONCLUSIONS

Sarcopenia is associated with significant fibrosis in subjects with chronic hepatitis B, specifically those with obesity, insulin resistance, metabolic syndrome and liver steatosis.

Predictors of failure to detect early hepatocellular carcinoma in patients with chronic hepatitis B who received regular surveillance

BACKGROUND

A proportion of chronic hepatitis B (CHB) patients are diagnosed with advanced hepatocellular carcinoma (HCC) despite regular surveillance.

AIMS

To determine predictors for HCC detection failure in CHB patients who underwent regular surveillance.

METHODS

CHB patients with well-preserved liver function, who underwent ultrasonography and alpha-foetoprotein (AFP) analysis every 6 months, were enrolled. Cox regression analysis was used to identify predictors for detection failure, defined as HCC initially diagnosed at Barcelona Clinic Liver Cancer (BCLC) stage B or C.

RESULTS

Of the 4590 CHB patients (mean age, 52.1 years; men, 61.6%), 169 patients were diagnosed with HCC (3.68%) and 35 (20.7%) HCC patients were initially diagnosed with HCC BCLC stage B or C. The cumulative incidence of HCC detection failure was 0.2% at year 1 and 1.3% at year 5. Multivariate analyses indicated that cirrhosis (hazard ratio [HR], 3.078; 95% CI, 1.389-6.821; P = 0.006), AFP levels ≥9 ng/mL (HR, 5.235; 95% CI, 2.307-11.957; P = 0.010), and diabetes mellitus (HR, 3.336; 95% CI, 1.341-8.296; P = 0.010) were independent predictors of HCC detection failure. Another model that incorporated liver stiffness (LS) values identified LS values ≥11.7 kPa (HR, 11.045; 95% CI, 2.066-59.037; P = 0.005) and AFP levels ≥9 ng/mL (HR, 4.802; 95% CI, 1.613-14.297; P = 0.005) as predictors of detection failure.

CONCLUSIONS

In CHB patients undergoing regular surveillance with ultrasonography and alpha-foetoprotein (AFP) analysis every 6 months, the HCC detection failure rate was not high (0.8% per person; 0.1% per test). However, careful attention should be paid in patients with advanced liver fibrosis (clinical cirrhosis or LS value >11.7 kPa), high AFP levels, or diabetes mellitus, who are prone to surveillance failure.

Brain Transplantation of Neural Stem Cells Cotransduced with Tyrosine Hydroxylase and GTP Cyclohydrolase 1 in Parkinsonian Rats

Neural stem cells (NSCs) of the central nervous system (CNS) recently have attracted a great deal of interest not only because of their importance in basic research on neural development, but also in terms of their therapeutic potential in neurological diseases, such as Parkinson's disease (PD). To examine if genetically modified NSCs are a suitable source for the cell and gene therapy of PD, an immortalized mouse NSC line, C17.2, was transduced with tyrosine hydroxylase (TH) gene and with GTP cyclohydrolase 1 (GTPCH1) gene, which are important enzymes in dopamine biosynthesis. The expression of TH in transduced C17.2-THGC cells was confirmed by RT-PCR, Western blot analysis, and immunocytochemistry, and expression of GTPCH1 by RT-PCR. The level of L-DOPA released by C17.2-THGC cells, as determined by HPLC assay, was 3793 pmol/106 cells, which is 760-fold higher than that produced by C17.2-TH cells, indicating that GTPCH1 expression is important for L-DOPA production by transduced C17.2 cells. Following the implantation of C17.2-THGcC NSCs into the striata of parkinsonian rats, a marked improvement in amphetamine-induced turning behavior was observed in parkinsonian rats grafted with C17.2-THGC cells but not in the control rats grafted with C17.2 cells. These results indicate that genetically modified NSCs grafted into the brain of the parkinsonian rats are capable of survival, migration, and neuronal differentiation. Collectively, these results suggest that NSCs have great potential as a source of cells for cell therapy and an effective vehicle for therapeutic gene transfer in Parkinson's disease.

Tenofovir versus tenofovir plus entecavir for chronic hepatitis B with lamivudine resistance and entecavir resistance

We compared the viral suppressive efficacy of tenofovir disoproxil fumarate (TDF) mono-rescue therapy (TDF group) and TDF plus entecavir (ETV) combination-rescue therapy (TDF + ETV group) in chronic hepatitis B (CHB) patients with lamivudine resistance and entecavir resistance. One hundred and thirty-three CHB patients with lamivudine and entecavir resistance were investigated. Ninety-six patients were treated with TDF and 37 with TDF + ETV for at least 6 months. We compared the virologic response rate (HBV DNA level <20 IU/mL) between the two groups and identified the predictive factors of treatment outcome. There were no significant differences between the two groups in demographic characteristics. Up to 24 months [median: 18 (range 6-24) months], 85.4% and 89.2% of the TDF group and TDF + ETV group, respectively, achieved a virologic response (P=.068). Only the HBV DNA level at baseline was significantly associated with a virologic response in the multivariate analysis. In a subanalysis of patients with HBV DNA levels ≥4 log (IU/mL) at baseline, a higher proportion of patients in the TDF + ETV group than the TDF group achieved a virologic response (92.9% vs 68.3%; P<.001), while 90% of patients with HBV DNA (IU/mL) levels <4 log in all both TDF and TDF + ETV groups achieved a virologic response. TDF mono-rescue therapy is a reasonable option in patients with lamivudine resistance and entecavir resistance. However, the combination strategy should be considered in patients with high baseline HBV DNA levels.

FOXM1-Induced PRX3 Regulates Stemness and Survival of Colon Cancer Cells via Maintenance of Mitochondrial Function

BACKGROUND & AIMS

Reagents designed to target cancer stem cells (CSCs) could reduce tumor growth, recurrence, and metastasis. We investigated the mitochondrial features of CSCs.

METHODS

Colon adenocarcinoma fragments were obtained from 8 patients during surgery at Busan Paik Hospital in Korea. We used immunohistochemistry and quantitative polymerase chain reaction to compare expression of mitochondrial peroxiredoxin 3 (PRX3) in CD133(+)CD44(+) Lgr5(+)cells (CSCs) vs CD133(-)CD44(-)Lgr5(-) colon tumor cells (non-CSCs). Cell survival and expression of mitochondrial-related genes were analyzed in the presence of 5-fluorouracil and/or antimycin A. We used small-interfering and short-hairpin RNAs and an overexpression vector to study PRX3, which functions in the mitochondria. CD133(+) cells with PRX3 knockdown or overexpressing PRX3 were grown as xenograft tumors in immunocompromised mice. Metastasis was studied after injection of tumor cells in spleens of mice. We used chromatin immunoprecipitation and reporter assays to characterize transcriptional regulation of PRX3 by forkhead box protein 1.

RESULTS

CSCs had a higher mitochondrial membrane potential and increased levels of adenosine triphosphate, Ca(2+), reactive oxygen species, and oxygen consumption than non-CSCs. Levels of PRX3 were increased in colon CSCs compared with non-CSCs. PRX3 knockdown reduced the viability of CSCs, but non non-CSCs, by inducing mitochondrial dysfunction. PRX3 knockdown reduced growth of CSCs as xenograft tumors or metastases in mice. The expression of FOXM1 activated transcription of PRX3 and expression of CD133 in colon CSCs.

CONCLUSIONS

Human colon CSCs have increased mitochondrial function compared with colon tumor cells without stem cell properties. Colon CSCs overexpress the mitochondrial gene PRX3, which is required for maintenance of mitochondrial function and tumorigenesis, and is regulated by forkhead box protein 1, which also regulates expression of CD133 in these cells. These proteins might be therapeutic targets for colorectal cancer.

Graft function measured by transient elastography in living donor liver transplantation: preliminary

INTRODUCTION

Liver stiffness measurements (LSMs) using transient elastography (TE) provide a noninvasive means to assess liver fibrosis that correlate with hepatic cholestasis. However, few studies have examined the correlation of TE to obtain LSMs with perioperative clinical and laboratory parameters in living donor liver transplantation (LDLT).

PATIENTS AND METHODS

We retrospectively reviewed forty-eight subjects who underwent LDLT between November 2010 and October 2012. All donors and recipients underwent TE, abdominal computed tomography (CT), and biochemical tests within 1 month before and at 1 week after transplantation. Using a cut-off LSM of 7.5 kPa, which we arbitrarily assigned to be indicative of significant fibrosis, we divided our study population into ≤7.5 kPa (group L; n = 15, 31.3%) versus >7.5 kPa; (group H; n = 33, 68.8%).

RESULTS

Pretransplantation serum total bilirubin, international normalized ratio, and Model for End-stage Liver Disease scores of recipients were significantly higher in group H than group L. Regarding the pretransplantation donor characteristics, the graft-recipient weight ratio was significantly smaller among those in group H (P = .039). In addition, the post-transplantation 1-week serum total bilirubin level was significantly higher in group H (2.3 mg/dL versus 1.2 mg/dL, P = .015), although neither biliary complications norhepatic congestion was identified by abdominal CT. Among the 1-week post-transplantation laboratory findings, only total bilirubin positively correlated with LSM (P = .044).

CONCLUSIONS

This pilot study suggested that a high LSM after LDLT suggests intrahepatic cholestasis and portal hypercirculation in the graft, irrespective of liver fibrosis, outflow obstruction, or biliary obstruction.

Analysis of two interacting bacterial populations with opposite substrate preferences

Interactions between two bacterial species which exhibit opposite substrate preferences in response to the same environmental conditions were investigated. Klebsiella oxytoca preferentially utilizes glucose over citrate as a substrate while Pseudomonas aeruginosa utilizes citrate over glucose. Both species were grown on single as well as mixed substrates, namely, D-glucose and citrate, with various ratios of inocula and substrates. Competition is observed between the two species with citrate alone while amensalism is observed with glucose alone. In mixed cultures-mixed substrates experiments, amensalism of K. oxytoca on P. aeruginosa prevailed until the exhaustion of glucose.

Synergistic effects of genetically engineered stem cells expressing cytosine deaminase and interferon-β via their tumor tropism to selectively target human hepatocarcinoma cells

Stem cells have received a great deal of attention for their clinical and therapeutic potential for treating human diseases and disorders. Recent studies have shown that it is possible to genetically engineered stem cells (GESTECs) to produce suicide enzymes that convert non-toxic prodrugs to toxic metabolites, selectively migrate toward tumor sites and reduce tumor growth. In this study, we evaluated whether these GESTECs are capable of migrating to hepatocarcinoma cells and examined the potential therapeutic efficacy of gene-directed enzyme prodrug therapy against liver cancer cells in cellular and animal models. A modified transwell migration assay was performed to determine the migratory capacity of GESTECs to Hep3B hepatocarcinoma cells. GESTECs, that is, HB1.F3.CD or HB1.F3.CD.interferon-β (IFN-β) cells, engineered to express a suicide gene, cytosine deaminase (CD), selectively migrated toward liver cancer cells. Treatment of Hep3B, human liver cancer cells, with the prodrug 5-fluorocytosine (5-FC) in the presence of HB1.F3.CD or HB1.F3.CD.IFN-β cells resulted in the inhibition of Hep3B cell growth. In a xenografted mouse model injected with hepatocarcinoma, we investigated the therapeutic effect of these stem cells. For 9 weeks, the xenografted mice were treated with HB1.F3.CD or HB1.F3.CD.IFN-β in the presence of 5-FC. A growth of tumor mass was inhibited about 40-50% in the mice treated with GESTECs and a prodrug. In addition, we further confirmed the cytotoxic effect on tumor cells by histological analysis and migratory effect of therapeutic stem cells. Taken together, GESTECs expressing a fusion gene encoding CD and IFN-β may exert a synergistic antitumor effect on this type of tumor.

Potential antitumor therapeutic strategies of human amniotic membrane and amniotic fluid-derived stem cells

As stem cells are capable of self-renewal and can generate differentiated progenies for organ development, they are considered as potential source for regenerative medicine and tissue replacement after injury or disease. Along with this capacity, stem cells have the therapeutic potential for treating human diseases including cancers. According to the origins, stem cells are broadly classified into two types: embryonic stem cells (ESCs) and adult stem cells. In terms of differentiation potential, ESCs are pluripotent and adult stem cells are multipotent. Amnion, which is a membranous sac that contains the fetus and amniotic fluid and functions in protecting the developing embryo during gestation, is another stem cell source. Amnion-derived stem cells are classified as human amniotic membrane-derived epithelial stem cells, human amniotic membrane-derived mesenchymal stem cells and human amniotic fluid-derived stem cells. They are in an intermediate stage between pluripotent ESCs and lineage-restricted adult stem cells, non-tumorigenic, and contribute to low immunogenicity and anti-inflammation. Furthermore, they are easily available and do not cause any controversial issues in their recovery and applications. Not only are amnion-derived stem cells applicable in regenerative medicine, they have anticancer capacity. In non-engineered stem cells transplantation strategies, amnion-derived stem cells effectively target the tumor and suppressed the tumor growth by expressing cytotoxic cytokines. Additionally, they also have a potential as novel delivery vehicles transferring therapeutic genes to the cancer formation sites in gene-directed enzyme/prodrug combination therapy. Owing to their own advantageous properties, amnion-derived stem cells are emerging as a new candidate in anticancer therapy.

Radiological response predicts survival following transarterial chemoembolisation in patients with unresectable hepatocellular carcinoma

BACKGROUND

It remains unclear whether initial compact lipiodol uptake after transarterial chemoembolisation (TACE) is associated with improved survival in patients with hepatocellular carcinoma (HCC).

AIM

To reveal the clinical relevance of compact lipiodolisation after TACE.

METHODS

We studied 490 patients with unresectable HCC who had first been treated with TACE. Compact lipiodolisation was defined as the absence of an arterial enhancing lesion, reflecting complete lipiodol uptake, as assessed by dynamic computed tomography (CT) 1 month after treatment. The rate of initial compact lipiodolisation was analysed according to multiplicity and size of tumour, and survival of patients who achieved compact lipiodolisation was compared to that of patients who did not.

RESULTS

Of the 490 patients, 409 (83.5%) were in Child-Pugh class A and 81 (16.5%) in class B. The rate of initial compact lipiodolisation in single HCCs was higher than that in multinodular HCCs (33.7% vs. 14.6%, P < 0.001). Among single HCCs, the rate of compact lipiodolisation in tumours ≤5, 5-10 and >10 cm was 46.6%, 13.6%, and 0% respectively. The 1-, 3- and 5-year survival rates of patients with compact uptake were 92.7%, 70.7% and 52.4% compared to 60.8%, 28.0% and 16.9% in patients with noncompact lipiodolisation. Multivariate analysis revealed that Child-Pugh class, alpha-fetoprotein level, tumour node metastasis stage, portal vein thrombosis and initial compact lipiodolisation were independent predictors of survival.

CONCLUSIONS

Initial compact lipiodol uptake after transarterial chemoembolisation is associated with improved survival in patients with unresectable hepatocellular carcinoma. Accordingly, initial complete lipiodolisation should be considered a relevant therapeutic target.

Human amniotic fluid-derived stem cells expressing cytosine deaminase and thymidine kinase inhibits the growth of breast cancer cells in cellular and xenograft mouse models

As human amniotic fluid-derived stem cells (hAFSCs) are capable of multiple lineage differentiation, extensive self-renewal and tumor targeting, they may be valuable for clinical anticancer therapies. In this study, we used hAFSCs as vehicles for targeted delivery of therapeutic suicide genes to breast cancer cells. hAFSCs were engineered to produce AF2.CD-TK cells in order to express two suicide genes encoding bacterial cytosine deaminase (CD) and herpes simplex virus thymidine kinase (HSV-TK) that convert non-toxic prodrugs, 5-fluorocytosine (5-FC) and mono-phosphorylate ganciclovir (GCV-MP), into cytotoxic metabolites, 5-fluorouracil (5-FU) and triphosphate ganciclovir (GCV-TP), respectively. In cell viability test in vitro, AF2.CD-TK cells inhibited the growth of MDA-MB-231 human breast cancer cells in the presence of the 5-FC or GCV prodrugs, or a combination of these two reagents. When the mixture of 5-FC and GCV was treated together, an additive cytotoxic effect was observed in the cell viability. In animal experiments using female BALB/c nude mouse xenografts, which developed by injecting MDA-MB-231 cells, treatment with AF2.CD-TK cells in the presence of 5-FC and GCV significantly reduced tumor volume and weight to the same extent seen in the mice treated with 5-FU. Histopathological and fluorescent staining assays further showed that AF2.CD-TK cells were located exactly at the site of tumor formation. Furthermore, breast tissues treated with AF2.CD-TK cells and two prodrugs maintained their normal structures (for example, the epidermis and reticular layers) while breast tissue structures in 5-FU-treated mice were almost destroyed by the potent cytotoxicity of the drug. Taken together, these results indicate that AF2.CD-TK cells can serve as excellent vehicles in a novel therapeutic cell-based gene-directed prodrug system to selectively target breast malignancies.

Neural stem cell-mediated CE/CPT-11 enzyme/prodrug therapy in transgenic mouse model of intracerebellar medulloblastoma

Medulloblastoma is a heterogeneous diffuse neoplasm that can be highly disseminated, and is the most common malignant childhood brain tumor. Although multimodal treatments have improved survival rates for patients with medulloblastoma, these tumors are associated with high morbidity and mortality. New treatment strategies are urgently needed to improve cure rates and, importantly, to spare normal brain tissue from neurotoxicity and patients from life-long cognitive and functional deficits associated with current therapies. In numerous preclinical brain tumor models, neural stem cells (NSCs) have shown great promise as delivery vehicles for therapeutic genes. Here, we have used an established, genetically modified human NSC line (HB1.F3.CD) to deliver carboxylesterase (CE) to cerebellar tumor foci and locally activate the prodrug CPT-11 (Irinotecan) to the potent topoisomerase I inhibitor SN-38. HB1.F3.CD NSC tumor tropism, intratumoral distribution and therapeutic efficacy were investigated in clinically relevant experimental models. Magnetic resonance imaging was used for in vivo tracking of iron nanoparticle-labeled NSCs, and to assess the therapeutic efficacy of CE-expressing HB1.F3.CD cells. As compared to controls, a significant decrease in tumor growth rate was seen in mice that received both NSCs and CPT-11 as their treatment regimen. Thus, this study provides proof-of-concept for NSC-mediated CE/CPT-11 treatment of medulloblastoma, and serves as a foundation for further studies toward potential clinical application.

Factors that affect the diagnostic accuracy of liver fibrosis measurement by Fibroscan in patients with chronic hepatitis B

BACKGROUND

Interquartile range/median value (IQR/M) of liver stiffness measurement (LSM) is a factor in chronic hepatitis C (CHC) leading to over estimation of fibrosis by Fibroscan.

AIM

To investigate factors that affect the accuracy of LSM in chronic hepatitis B (CHB).

METHODS

One hundred and ninety-nine patients were enrolled. Only procedures yielding > or =10 valid measurements were considered reliable. Liver fibrosis was evaluated using the Batts and Ludwig system. Liver biopsy (LB) specimens <15 mm were considered ineligible.

RESULTS

The mean age (142 men and 57 women) was 40.1 years. A significant discordance (discordance of at least two stages between LB and LSM) was identified in 38 (19.1%) and 47 (23.6%) patients respectively, according to Marcellin et al. and Chan et al.'s cutoff values. In multivariate analyses, BMI and fibrosis stage (F0-2 vs. F3-4) were identified as independent predictors for significant discordance (P = 0.040; hazard ratio [HR], 1.126; 95% confidence interval [CI], 1.005-1.261 and P = 0.036; HR, 0.450; 95% CI, 0.213-0.949 respectively) with Marcellin et al.'s cutoffs, whereas fibrosis stage was the only independent predictor (P = 0.004; HR, 0.300; 95% CI, 0.131-0.685) with Chan's cutoffs.

CONCLUSIONS

Success rate and IQR/M were not predictive factors of the accuracy for diagnosing liver fibrosis by Fibroscan in CHB. Fibrosis stage (F0-2) was the only factor to predict significant discordance between LB and LSM.

Physical activity and metabolic syndrome in Korean children

Little is known about whether lifestyle factors such as dietary intake, physical activity (PA), and cardio/respiratory fitness (CRF) are associated with metabolic risk factors in Korean children. The purpose of the study was to investigate the relationships among those lifestyle-related modifiable factors and the clustering of metabolic risk factors in young Korean children. In a cross-sectional study, we studied 246 Korean children (mean+/-SD; age: 12.6+/-0.5 years, BMI: 19.9+/-3.2 kg/m (2)) who were recruited from local elementary schools. In the total study population, physical activity and CRF were inversely associated with metabolic risk factors including body fatness, blood pressures, blood lipids and glucose. Daily caloric intake and proportion of carbohydrates were positively associated with BMI and percent body fat only. Multivariate regression analyses showed that physical activity was independently and inversely associated with the clustering of metabolic risk factors, even after adjustments for age, sex, sexual maturation, dietary intake, and CRF. Overall, the current findings of the study suggest that physical activity rather than CRF and/or dietary intake is an independent predictor for the clustering of metabolic risk factors in Korean children.

Cystatin C expression in ischemic white matter lesions

OBJECTIVES

To study the involvement of cystatin C in the progression of ischemic white matter lesions (WMLs).

MATERIALS AND METHODS

Cystatin C levels in the cerebrospinal fluid (CSF) of patients with cerebrovascular disease, and also in primary and established human neural cell cultures were investigated. For pathologic analysis, cystatin C immunoreactivity was investigated in the white matter of patients with severe WMLs, mild WMLs or controls.

RESULTS

Cystatin C levels in the CSF of patients with Fazekas WML grade 3 [14 with hypertension; W/HT(+) and nine without hypertension; W/HT(-)] were lower than those in 38 patients with grade 0-1 (P = 0.0022 and P < 0.0001 respectively). Immunohistochemical study showed that the cystatin C immunoreactivity was found in astrocytes, and the number of astrocytes in the white matter in the severe WML group was decreased when compared with that in controls (P = 0.0027) and in the mild WML group (P = 0.0024). In human neural cell cultures, treatments with thrombin, matrix metalloproteinases and interleukin 1 beta increased the expression of cystatin C mRNA in human astrocytes and hybrid neurons, but an enzyme-linked immunosorbent assay revealed that only thrombin significantly increased the production and secretion of cystatin C in astrocytes.

CONCLUSIONS

These results suggest that low levels of CSF cystatin C in ischemic WMLs might be due to the decreased number of astrocytes that secrete cystatin C in response to the stimuli of proteases and inflammatory cytokines.

Human neural stem cells target and deliver therapeutic gene to experimental leptomeningeal medulloblastoma

Medulloblastomas are highly malignant neuroectodermal cerebellar tumors of children. One of the reasons for the difficulty for the treatment of medulloblastomas is their inherent tendency to metastasize through the cerebrospinal fluid (CSF) pathway leading to leptomeningeal dissemination. Recently, genetically modified neural stem cells (NSCs) were shown to have the capability of selectively migrating into glioma mass and delivering therapeutic agents with significant therapeutic benefits. In the present study, we applied the NSC strategy to target medulloblastomas, particularly their leptomeningeal dissemination. We used NSCs that were retrovirally transduced with the cytosine deaminase gene (CD-NSCs). In vitro studies demonstrated that CD-NSCs had sufficient migratory activity toward medulloblastoma cells and exerted a remarkable bystander effect on these cells following the application of 5-fluorocytosine (5-FC). It is noteworthy that neutralization of the hepatocyte growth factor blocked their migration In animal studies using our leptomeningeal dissemination model, CD-NSCs implanted directly into CSF space were shown to distribute diffusely within the disseminated tumor cells and could provide remarkable antitumor effect after intraperitoneal administration of 5-FC. Furthermore, CD-NSC treatment followed by 5-FC administration prolonged survival periods significantly in experimental animals. Our data suggest that the CD-NSC strategy can also be applied to target leptomeningeal dissemination of medulloblastomas.

Potential differentiation of human mesenchymal stem cell transplanted in rat corpus cavernosum toward endothelial or smooth muscle cells

One of the causes of erectile dysfunction (ED) is the damaged penile cavernous smooth muscle cells (SMCs) and sinus endothelial cells (ECs). To investigate the feasibility of applying immortalized human mesenchymal stem cells (MSCs) to penile cavernous ECs or SMCs repair in the treatment of ED, the in vivo potential differentiation of the immortalized human MSCs toward penile cavernous endothelial or smooth muscle was investigated. One clone of immortalized human bone marrow mesenchymal stem cell line B10 cells via retroviral vector encoding v-myc were transplanted into the cavernosum of the Sprague-Dawley rats and harvested 2 weeks later. The expression of CD31, von Willebrand factor (vWF), smooth muscle cell actin (SMA), calponin and desmin was determined immunohistochemically in rat penile cavernosum. Multipotency of B10 to adipogenic, osteogenic or chondrogenic differentiation was found. Expression of EC specific markers (CD31 or vWF protein) and expression of SMC specific markers (calponin, SMA or desmin protein) were demonstrated in grafted B10 cells. When human MSCs were transplanted into the penile cavernosum, they have the potential to differentiate toward ECs or SMCs. Human MSCs may be a good candidate in the treatment of penile cavernosum injury.

Characterisation of heavy metal tolerance and biosorption capacity of bacterium strain CPB4 (Bacillus spp.)

A heavy metal resistant bacterium Bacillus spp. strain CPB4 was isolated from heavy metal contaminated soil in Korea and further characterised. The CPB4 strain showed a high capacity for uptake of heavy metal Pb (Pb > Cd > Cu > Ni > Co > Mn > Cr > Zn) both in single and in mixed heavy metal solution. Optimal conditions for heavy metal uptakes of CPB4 strain were 20-40 degrees C culture temperature, 5-7 pH and 24 h pre-culture times. TEM showed that large amounts of the electron-dense granules (heavy metal complexes) were found mainly on the cell wall and cell membrane. Furthermore, more than 90% of adsorbed heavy metals were distributed both in cell wall and in cell membrane fractions. The amount of heavy metal uptake was remarkably decreased by reducing the crude protein contents when cells were treated by alkali solutions. Therefore, this study showed one of the possible examples for useful bioremediation.

Neuroprotective role of microglia expressing interleukin-4

Little is known about the underlying mechanisms responsible for the death of activated microglia and the functional consequences of the death of these cells, especially in vivo. We show here that intracortical injection of lipopolysaccharide (LPS) led to upregulation of interleukin-4 (IL-4) immunoreactivity, followed by a substantial loss of microglia 3 days later, as visualized by complement receptor type 3 (OX-42) immunostaining and tomato lectin staining. Cells positive for caspase-3 and terminal deoxynucleotidyl transferase mediated fluorescein-dUTP nick-end labeling (TUNEL) were also localized within LPS-activated microglia. IL-4 immunoreactivity was detected as early as 12 hr post-LPS, disappearing at 72 hr. Surprisingly, IL-4 immunoreactivity was detected exclusively in microglia, but not in astrocytes or neurons. In addition, IL-4-neutralizing antibodies markedly increased the survival of activated microglia at 3 days post-LPS. The expression of inducible nitric oxide synthase (iNOS) and tumor-necrosis factor (TNF)-alpha was sustained in parallel in activated microglia, consequently increasing neuronal cell death. To our knowledge, this study is the first to show the endogenous expression of IL-4 in LPS-activated microglia in vivo. Our findings suggest that IL-4 may regulate brain inflammation by inducing the death of activated microglia in vivo and increasing neuronal survival.

Using the chorions of fertilized zebrafish eggs as a biomaterial for the attachment and differentiation of mouse stem cells

The development of proper biomaterials is critical for the success of cell therapy and modern tissue engineering. Here, we extruded the yolk and remaining inner mass from fertilized zebrafish eggs and used the resulting chorions as a biomaterial for the differentiation and attachment of mouse P19 embryonic carcinoma (EC) cells. Cells inserted into the chorion showed the spontaneous formation of embryoid body due to the repulsive cell adhesion of the chorion and differentiated specifically into neural cells and cardiomyocytes. In contrast, dissolved chorion extracellular matrix (ECM) conferred enhanced cell attachment on it, suggesting that a unique property of the zebrafish chorion with nanoporous structure appears to be responsible for the simple and controllable embryoid formation for stem cell differentiation. These results indicate that chorions from fertilized zebrafish eggs may be used as an extracellular matrix alternative and applied for stem cell differentiation to specific cell lineages.

Influence of VEGF gene polymorphisms on the severity of ankylosing spondylitis

OBJECTIVES

To investigate the role of polymorphisms of the vascular endothelial growth factor (VEGF) gene in susceptibility to ankylosing spondylitis (AS), and their relationship to clinical features and radiographic severity.

METHODS

This study included 157 patients with AS and 140 healthy unrelated controls. Polymorphisms of the VEGF gene were analysed by the polymerase chain reaction (PCR)-restriction fragment length polymorphism assay and amplification refractory mutation system-PCR. Haplotypes were reconstructed using the Bayesian algorithm. Radiographic severity was assessed by the Bath Ankylosing Spondylitis Radiological Index (BASRI).

RESULTS

The genotype frequencies of the polymorphisms were in Hardy-Weinberg equilibrium. The distributions of genotypes and alleles did not differ between AS patients and controls. Among the six haplotypes reconstructed based on the tight linkage disequilibrium at positions -2578, -1154 and -634 (pairwise linkage disequilibrium coefficient, r = 0.361-0.706), no haplotype was associated with susceptibility to AS. Clinical features were analysed for the four haplotypes (CGC, CGG, AAG, AGG) which were prevalent. In carriers of the AGG haplotype, the frequency of cervical spine involvement was significantly higher (P = 0.002, P(corr) = 0.036) and that of patients showing a BASRI score >6 was also higher (P = 0.025, P(corr) = 0.45).

CONCLUSIONS

This study demonstrates that polymorphisms of the VEGF gene may contribute to disease severity in AS.

Retinoic acid-mediated induction of neurons and glial cells from human umbilical cord-derived hematopoietic stem cells

Recent studies reporting trans-differentiation of mononucleated cells derived from human umbilical cord blood into neuronal cells aroused interest among investigators for their clinical implication and significance in regenerative medicine. In the present study, purified populations of hematopoietic stem cells were isolated via magnetic bead sorting and fluorescence-activated cell sorter (FACS) using a specific CD133 antibody, a cell type-specific marker for hematopoietic stem cells, and grown in culture in the presence of retinoic acid (RA). CD133+ hematopoietic stem cells expressed neuronal and glial phenotypes after RA treatment. RT-PCR analysis indicated that the RA treated CD133+ cells expressed mRNA transcripts for ATP-binding cassettes transporter ABCG2 (a universal stem cell marker), nestin (a specific cell type marker for neural stem cells), Musashi1 (a specific marker for neural stem cells) and RA receptors (RAR) including RAR-alpha, RAR-beta, and retinoid X receptor (RXR)-gamma. RA-treated CD133+ cells expressed mRNA transcripts for neuron-specific markers neurofilament proteins (NF-L, -M, -H) and synaptophysin as determined by RT-PCR, structural proteins characteristic of neurons including tubulin beta III and neuron specific enolase (NSE) by Western blot, and neuron-specific markers NeuN and microtubule-associated protein-2 (MAP2) by immunocytochemistry. RA-treated CD133+ cells also expressed the astrocyte-specific marker glial fibrillary acidic protein (GFAP), as demonstrated by RT-PCR, Western blot, and immunocytochemistry. In addition, RA-treated CD133+ cells expressed cell type-specific markers for oligodendrocytes including myelin basic protein (MBP) as shown by RT-PCR, proteolipid protein (PLP) by Western blot analysis, and cyclic nucleotide phosphodiesterase (CNPase) by immunostaining. Upregulated expression of several basic helix-loop-helix (bHLH) transcription factors important for early neurogenesis, including Otx2, Pax6, Wnt1, Olig2, Hash1 and NeuroD1, was also demonstrated in CD133+ cells after RA treatment. These results indicate that human cord blood-derived CD133+ hematopoietic stem cells could trans-differentiate into neural cell types of neuron-like cells, astrocytes, and oligodendrocytes by RA treatment.

Interferon gamma stimulates beta-secretase expression and sAPPbeta production in astrocytes

Neurons, but not astrocytes, are known as the major source of Abeta, because astrocytes express low levels of putative beta-secretase (BACE). Astrocytes near senile plaque cores show enhanced levels of BACE protein expression, however, suggesting that astrocytes can contribute to Abeta production under pathological conditions. To investigate factors that stimulate BACE protein expression in astrocytes, we tested the effects of interleukin-1beta (IL-1beta) and interferon-gamma (IFN-gamma) on BACE protein expression in U373MG astrocytoma cells and primary astrocyte cultures from Tg2576 mouse brains. BACE protein expression and sAPPbeta production were dramatically increased, without changes in holo APP levels, following IFN-gamma treatment in both cell types. AG490, which is a blocker of IFN-gamma-induced STAT signaling, decreased IFN-gamma-induced BACE protein expression and sAPPbeta production in a dose-dependent manner. These results show that astrocytes are capable of expressing BACE and producing sAPPbeta in response to certain stimulating factors, and IFN-gamma is one such factor.

Relationship between urinary profile of the endogenous steroids and postmenopausal women with stress urinary incontinence

AIMS

The aims of this study were to investigate whether endogenous steroid hormones are (1) related to pathogenesis of stress urinary incontinence after menopause, (2) are related to severity of stress urinary incontinence, and (3) are related to prognostic parameters of stress urinary incontinence.

METHODS

Twenty post-partum women with clinically diagnosed stress urinary incontinence and 20 age-matched postmenopausal women without stress urinary incontinence (control group) were evaluated. We compared urinary profile of the endogenous steroid hormones patients with stress urinary incontinence and controls, and between grade I and grade II of stress urinary incontinence. We also investigated the relationship between urinary profile of the endogenous steroid hormones and prognostic parameters of stress urinary incontinence (maximal urethral closure pressure, functional urethral length, Valsalva leak point pressure, cough leak point pressure, posterior urethrovesical angle, bladder neck descent, and stress urethral axis). The ages of the patients and those in the control group were 64.3 +/- 5.6 and 57.5 +/- 3.8 years old and the body mass indexes were 24.96 +/- 3.14 and 22.11 +/- 2.73 kg/m2 in patients and in normal subjects, respectively. Nine patients were grade I and 11 were grade II. Estrone and 17beta-estradiol only were detected in all subjects, regardless of control or patient group. It is noteworthy that there were no significant differences (P > 0.05) in the levels of estrone and 17beta-estradiol in the urine of postmenopausal normal subjects compared with in the urine of postmenopausal patients with urinary incontinence. E2/E1 ratio was not different between the two groups (P > 0.05). Among the objective steroids, DHEA, Delta4-dione, Delta5-diol, Te, DHT, 16alpha-DHT, 11-keto An, THDOC, and THB were not detected either in the urine of normal subjects and nor in the urine of the patients. After comparing androgen levels between normal subjects and patients, no significant differences (P>0.05) were detected, except for 5alpha-THB and 5alpha-THF. Neither 5alpha-THB or 5alpha-THF were detected in the patients' urine. Et/An (11beta-OH Et/11beta-OH An) concentration ratios were not significantly different between the two groups, either (P > 0.05). There were not significant differences of concentrations (micromol/g creatinine) of urinary steroids between grade I and grade II of stress urinary incontinence. Pregnanediol was significantly related to bladder neck descent in supine and sitting positions (R = 0.79, P = 0.01, and R = 0.73, P = 0.03, respectively), and pregnanetriol was significantly related to maximal urethral closure pressure and functional urethral length (R = 0.68, P = 0.04, and R = -0.79, P = 0.01, respectively). Androsterone was significantly related to bladder neck descent in supine and sitting positions (R = 0.68, P = 0.04, and R = 0.78, P = 0.01, respectively). 5-AT was significantly related to bladder neck descent in sitting position and stress urethral axis (R = 0.72, P = 0.03, and R = -0.71, P = 0.03). 11-keto Et was significantly related to bladder neck descent in supine and sitting positions and related to stress urethral axis (R = 0.82, P = 0.01, and R = 0.81, P = 0.01, R = -0.67, P = 0.04, respectively). THS was significantly related to bladder neck descent in supine and sitting positions and related to stress urethral axis (R = 0.76, P = 0.02, and R = 0.74, P = 0.02, R = -0.68, P = 0.04, respectively). THE was significantly related to bladder neck descent in sitting position (R = 0.67, P = 0.04).beta-Tetrahydrocortisol/alpha-tetrahydrocortisol (beta-THF/alpha-THF) and alpha-cortol were significantly related to maximal urethral closure pressure and functional urethral length (R = 0.74, P = 0.02, and R = -0.92, P = 0.01; R = 0.71, P = 0.36, and R = -0.87, P = 0.000, respectively). 17beta-estradiol (E2) was significantly related to bladder neck descent in supine position (R = -0.62, P = 0.04) and 17beta-estradiol/estrone (E2/E1) was significantly related to cough leak point pressure (R = 0.79, P = 0.01). In conclusion, the urinary concentrations of endogenous steroid metabolites in postmenopausal patients with stress urinary incontinence were not significantly different from normal patients and were not significantly different between grade I and grade II patients with stress urinary incontinence. Some endogenous steroid metabolites were positively or negatively significantly related to prognostic parameters of stress urinary incontinence.

Human neural stem cells: electrophysiological properties of voltage-gated ion channels

We have characterized the profile of membrane currents in an immortalized human neural stem cell line, HB1.F3 cells, using whole-cell patch clamp technique. Human neural stem cell line generated from primary cell cultures of embryonic human telencephalon using a replication-incompetent retroviral vector containing v-myc expresses nestin, a cell type-specific marker for neural stem cells. The human neural stem cells expressed both outward and inward K(+) currents with no evidence for Na(+) currents. The density of the outward, delayed rectifying type K(+) current was 1.8 +/- 0.015 nA/pF, and that of the inwardly rectifying K(+) current was 0.37 +/- 0.012 nA/pF (at 30 mM of [K(+)](o)). In order to induce neuronal differentiation of the neural stem cells, a full-length coding region of NeuroD, a neurogenic transcription factor, was transfected into HB1.F3 cells. Introduction of NeuroD induced expression of Na(+) currents with the current density of 0.042 +/- 0.011 nA/pF. The presence of two types of K(+) currents and expression of Na(+) currents induced by NeuroD appear to reflect the characteristic physiological features of human neural stem cells.

Isolation of various forms of sterol beta-D-glucoside from the seed of Cycas circinalis: neurotoxicity and implications for ALS-parkinsonism dementia complex

The factors responsible for ALS-parkinsonism dementia complex (ALS-PDC), the unique neurological disorder of Guam, remain unresolved, but identification of causal factors could lead to clues for related neurodegenerative disorders elsewhere. Earlier studies focused on the consumption and toxicity of the seed of Cycas circinalis, a traditional staple of the indigenous diet, but found no convincing evidence for toxin-linked neurodegeneration. We have reassessed the issue in a series of in vitro bioassays designed to isolate non-water soluble compounds from washed cycad flour and have identified three sterol beta-d-glucosides as potential neurotoxins. These compounds give depolarizing field potentials in cortical slices, induce alterations in the activity of specific protein kinases, and cause release of glutamate. They are also highly toxic, leading to release of lactate dehydrogenase (LDH). Theaglycone form, however, is non-toxic. NMDA receptor antagonists block the actions of the sterol glucosides, but do not compete for binding to the NMDA receptor. The most probable mechanism leading to cell death may involve glutamate neuro/excitotoxicity. Mice fed cycad seed flour containing the isolated sterol glucosides show behavioral and neuropathological outcomes, including increased TdT-mediated biotin-dUTP nick-end labelling (TUNEL) positivity in various CNS regions. Astrocytes in culture showed increased caspase-3 labeling after exposure to sterol glucosides. The present results support the hypothesis that cycad consumption may be an important factor in the etiology of ALS-PDC and further suggest that some sterol glucosides may be involved in other neurodegenerative disorders.

Generation and characterization of immortalized human microglial cell lines: expression of cytokines and chemokines

Microglia are a major glial component of the central nervous system (CNS), play a critical role as resident immunocompetent and phagocytic cells in the CNS, and serve as scavenger cells in the event of infection, inflammation, trauma, ischemia, and neurodegeneration in the CNS. Studies of human microglia have been hampered by the difficulty of obtaining sufficient numbers of human microglia. One way to circumvent this difficulty is to establish permanent cell lines of human microglia. In the present study we report the generation of immortalized human microglial cell line, HMO6, from human embryonic telencephalon tissue using a retroviral vector encoding myc oncogene. The HMO6 cells exhibited cell type-specific antigens for microglia-macrophage lineage cells including CD11b (Mac-1), CD68, CD86 (B7-2), HLA-ABC, HLA-DR, and ricinus communis agglutinin lectin-1 (RCA), and actively phagocytosed latex beads. In addition, HMO6 cells showed ATP-induced responses similar to human primary microglia in Ca2+ influx spectroscopy. Both human primary microglia and HMO6 cells showed the similar cytokine gene expression in IL-1beta, IL-6, IL-8, IL-10, IL-12, IL-15, and TNF-alpha. Using HMO6 cells, we investigated whether activation was induced by Amyloid-beta fragments or lipopolysaccharide (LPS). Treatment of HMO6 cells with Amyloid-beta 25-35 fragment (Abeta(25-35)) or Amyloid-beta 1-42 fragment (Abeta(1-42)) led to increased expression of mRNA levels of cytokine/chemokine IL-8, IL-10, IL-12, MIP-1beta MIP-1, and MCP-1, and treatment with LPS produced same results. Expression of TNF-alpha and MIP1-alpha was not detected in unstimulated HMO6 cells, but their expression was later induced by long-term exposure to Abeta(25-35) or Abeta(1-42.) ELISA assays of spent culture media showed increased protein levels of TNF-alpha and IL-8 in HMO6 cells following treatment with Abeta(25-35) or LPS. Taken together, our results demonstrate that treatment of human primary microglia and HMO6 immortalized human microglia cell line with Abeta(25-35), Abeta(1-42) and LPS upregulate gene expression and protein production of proinflammatory cytokines and chemokines in these cells. The human microglial cell line HMO6 exhibits similar properties to those documented in human microglia and should have considerable utility as an in vitro model for the studies of human microglia in health and disease.

Antioxidant effect of melatonin in human retinal neuron cultures

This study investigates whether the neurohormone melatonin can prevent the retinal neuronal injury caused by reactive oxygen species (ROS) in cultured human retinal neuronal cells. Cultures of human retinal neuronal cells established from a variety of donors were grown to 14 days and then subjected to experimental hypoxanthine/xanthine oxidase (HX/XO)-induced injury. Intracellular production of ROS by administration of HX/XO was confirmed by flow cytometry; the ROS resulted in both apoptotic and necrotic pattern of cell death in the retinal neuron cultures. The efficacy of melatonin against ROS injury was quantitated by MTT assay, enzyme immunoassay, and immunocytochemistry for neurofilament protein. The antioxidative effect of melatonin was compared with that of alpha-tocopherol. Retinal neuronal injury significantly reduced in a dose-response manner by a treatment of 1.0-8.0 mM alpha-tocopherol. Melatonin, in concentrations of more than 2.0 mM, also significantly reduced the injury. About 70% of cells are rescued by pretreatment with 1.0 mM alpha-tocopherol and 8.0 mM melatonin in the MTT assay. Our observations suggest that melatonin can rescue retinal neurons from ROS injury in human retinal cell cultures.

Inhibition of store-operated Ca(2+) influx by acidic extracellular pH in cultured human microglia

The effects of extracellular acidification on Ca(2+)-dependent signaling pathways in human microglia were investigated using Ca(2+)-sensitive fluorescence microscopy. Adenosine triphosphate (ATP) was used to elicit Ca(2+) responses primarily dependent on the depletion of intracellular endoplasmic reticulum (ER) stores, while platelet-activating factor (PAF) was used to elicit responses primarily dependent on store-operated channel (SOC) influx of Ca(2+). The duration of transient responses induced by ATP was not significantly different in standard physiological pH 7.4 (mean duration 30.2 +/- 2.5 s) or acidified pH 6.2 (mean duration 31.7 +/- 2.8 s) extracellular solutions. However, the time course of the PAF response at pH 7.4 was significantly reduced by 87% with external pH at 6.2. These results suggest that acidification of extracellular solutions inhibits SOC entry of Ca(2+) with little or no effect on depletion of ER stores. Changes of extracellular pH over the range from 8.6 to 6.2 during the development of a sustained SOC influx induced by PAF resulted in instantaneous modulation of SOC amplitude indicating a rapidly reversible effect of pH on this Ca(2+) pathway. Whole-cell patch clamp recordings showed external acidification blocked depolarization-activated outward K(+) current indicating cellular depolarization may be involved in the acid pH inhibition. Since SOC mediated influx of Ca(2+) is strongly modulated by membrane potential, the electrophysiological data suggest that acidification may act to inhibit SOC by cellular depolarization. These results suggest that acidification observed during cerebral ischemia may alter microglial responses and functions.

Calcium/calmodulin kinase II activity of hippocampus in kainate-induced epilepsy

This study investigated calcium/calmodulin kinase II (CaMKII) activity related to long-standing neuronal injury of the hippocampus in kainate (KA)-induced experimental temporal lobe epilepsy. Epileptic seizure was induced by injection of KA (1 microg/microL) dissolved in phosphate buffer (0.1 M, pH 7.4) into the left amygdala. Clinical seizures, histopathologic changes and CaMKII activity of the hippocampus were evaluated. Characteristic early limbic and late seizures were developed. Hippocampal CaMKII activity increased significantly 4 and 8 weeks after intra-amygdaloid injection of KA, when late seizures developed. The histopathologic changes of the hippocampus included swelling of neuronal cytoplasm with nuclear pyknosis and loss of neurons in CA3 during this period. The increased activity of CaMKII may correlate with appearance of distant damage in the hippocampus. The above results indicate that intra-amygdaloid injection of KA produces excitatory signals for ipsilateral CA3 neurons in the hippocampus and that subsequently increased levels of CaMKII in postsynaptic neurons induce neuronal injury via phosphorylation of N-methyl-D-aspartate type glutamate receptor.

Acute actions of tumor necrosis factor-alpha on intracellular Ca(2+) and K(+) currents in human microglia

The effects of acute application of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNFalpha) on levels of intracellular Ca(2+) ([Ca(2+)]i) and on whole-cell outward and inward K(+) currents were studied in cultured human microglia. TNFalpha elicited a linear increase in [Ca(2+)]i to a plateau level in microglia bathed in either standard physiological saline solution or Ca(2+)-free physiological saline solution. The rate of increase of [Ca(2+)]i or the level of [Ca(2+)]i attained was not significantly altered in the absence of external Ca(2+) indicating that Ca(2+) influx did not contribute appreciably to the cytokine-induced rise in [Ca(2+)]i. This point was directly confirmed using Mn(2+) quenching where no change in signal fluorescence was observed with TNFalpha treatment of microglia in Ca(2+)-free physiological saline solution. The rate of increase of [Ca(2+)]i induced by TNFalpha in Ca(2+)-free physiological saline solution was not altered by prior application of ATP to deplete inositol triphosphate stores indicating that these stores did not contribute to the cytokine response. In whole-cell patch clamp recordings, the acute treatment of human microglia with TNFalpha led to the expression of an outward K(+) current in one-third (14 of 41) of cells. This current was activated at potentials positive to -30 mV, showed rapid kinetics of activation with no evident inactivation and had an I-V relation exhibiting outward rectification. Analysis of tail currents showed reversal of the outward K(+) current near -70 mV and tetraethylammonium (10 mM) inhibited the outward K(+) current to 24% of control level. Acute application of TNFalpha had no effect to alter inward rectifier currents generated from voltage ramps. The signaling pathways involving TNFalpha modulation of [Ca(2+)]i and K(+) channels in human microglia may contribute to functional and pathological actions of the cytokine in the brain.

Bcl-2 blocks cisplatin-induced apoptosis by suppression of ERK-mediated p53 accumulation in B104 cells

Bcl-2 has been reported to inhibit neurotoxicity induced by cisplatin. However, neither the mechanism of cisplatin-induced neurotoxicity nor the mechanism by which Bcl-2 confers neuroprotection is clear. In this study, the signaling pathways involved in cisplatin-induced neurotoxicity were examined using a rat neuroblastoma cell line, B104. Treatment of B104 cells with cisplatin induced apoptosis, accompanying the accumulation of p53 and Bax protein. Interestingly, extracellular signal-regulated kinase 1/2 (ERK1/2) activities of MAP kinases were markedly enhanced prior to cisplatin-induced accumulation of p53 and Bax. Inhibition of ERK1/2 activities using PD98059, a selective MEK inhibitor, blocked the apoptotic cell death preventing cisplatin-induced accumulation of p53 and Bax. These results suggest that ERK mediates cisplatin-induced p53 activation to trigger apoptosis in B104 cells. Overexpression of Bcl-2 in B104 cells resulted in the complete resistance to cisplatin-induced apoptosis blocking ERK activation and the subsequent signaling pathway of p53. Our study clearly demonstrates that the action site of Bcl-2 localizes upstream of ERK in cisplatin-induced apoptotic signaling pathway.

Segregation of human neural stem cells in the developing primate forebrain

Many central nervous system regions at all stages of life contain neural stem cells (NSCs). We explored how these disparate NSC pools might emerge. A traceable clone of human NSCs was implanted intraventricularly to allow its integration into cerebral germinal zones of Old World monkey fetuses. The NSCs distributed into two subpopulations: One contributed to corticogenesis by migrating along radial glia to temporally appropriate layers of the cortical plate and differentiating into lamina-appropriate neurons or glia; the other remained undifferentiated and contributed to a secondary germinal zone (the subventricular zone) with occasional members interspersed throughout brain parenchyma. An early neurogenetic program allocates the progeny of NSCs either immediately for organogenesis or to undifferentiated pools for later use in the "postdevelopmental" brain.

Analysis of GABA(A)- and GABA(B)-receptor mediated effects on intracellular Ca(2+) in DRG hybrid neurones

1. Using pharmacological analysis and fura-2 spectrofluorimetry, we examined the effects of gamma-aminobutyric acid (GABA) and related substances on intracellular Ca(2+) concentration ([Ca(2+)]i) of hybrid neurones, called MD3 cells. The cell line was produced by fusion between a mouse neuroblastoma cell and a mouse dorsal root ganglion (DRG) neurone. 2. MD3 cells exhibited DRG neurone-like properties, such as immunoreactivity to microtubule-associated protein-2 and neurofilament proteins. Bath applications of capsaicin and alpha, beta-methylene adenosine triphosphate reversibly increased [Ca(2+)]i. However, repeated applications of capsaicin were much less effective. 3. Pressure applications of GABA (100 microM), (Z)-3-[(aminoiminomethyl) thio] prop-2-enoic acid sulphate (ZAPA; 100 microM), an agonist at low affinity GABA(A)-receptors, or KCl (25 mM), transiently increased [Ca(2+)]i. 4. Bath application of bicuculline (100 nM - 100 microM), but not picrotoxinin (10 - 25 microM), antagonized GABA-induced increases in [Ca(2+)]i in a concentration-dependent manner (IC(50)=9.3 microM). 5. Ca(2+)-free perfusion reversibly abolished GABA-evoked increases in [Ca(2+)]i. Nifedipine and nimodipine eliminated GABA-evoked increases in [Ca(2+)]i. These results imply GABA response dependence on extracellular Ca(2+). 6. Baclofen (500 nM - 100 microM) activation of GABA(B)-receptors reversibly attenuated KCl-induced increases in [Ca(2+)]i in a concentration-dependent manner (EC(50)=1.8 microM). 2-hydroxy-saclofen (1 - 20 microM) antagonized the baclofen-depression of the KCl-induced increase in [Ca(2+)]i. 7. In conclusion, GABA(A)-receptor activation had effects similar to depolarization by high external K(+), initiating Ca(2+) influx through high voltage-activated channels, thereby transiently elevating [Ca(2+)]i. GABA(B)-receptor activation reduced Ca(2+) influx evoked by depolarization, possibly at Ca(2+)-channel sites in MD3 cells.

Synthesis of new artemisinin analogues from artemisinic acid modified at C-3 and C-13 and their antimalarial activity

Artemisinic acid (2) was modified through allylic oxidation at C-3 or conjugate addition at C-13 to afford 12 methyl artemisinate derivatives (4-15). Photooxidation of the derivatives yielded eight new artemisinin analogues, including 13-cyanoartemisinin (16), 13-methoxycarbonyl artemisinin (17), 13-methoxyartemisinin (18), 13-ethylsulfonylartemisinin (19), 13-nitromethylartemisinin (20), 13-(1-nitroethyl)artemisinin (21), (3R)-3-hydroxyartemisinin (22), and (3R)-3-acetoxyartemisinin (23). Among the analogues, only compound 20 had antimalarial activity comparable to artemisinin (1).

Inhibitory activity for chitin synthase II from Saccharomyces cerevisiae by tannins and related compounds

In the course of search for potent inhibitors of chitin synthase II from natural resources, seven tannins and related compounds were isolated from the aerial part of Euphorbia pekinensis and identified as gallic acid (1), methyl gallate (2), 3-O-galloyl-(-)-shikimic acid (3), corilagin (4), geraniin (5), quercetin-3-O-(2"-O-galloyl)-beta-D-glucoside (6), and kaempferol-3-O-(2"-O-galloyl)-beta-D-glucoside (7). These and nine related compounds, (-)-quinic acid (8), (-)-shikimic acid (9), ellagic acid (10), kaempferol (11), quercetin (12), quercitrin (13), rutin (14), quercetin-3-O-(2"-O-galloyl)-beta-D-rutinoside (15) and 1,3,4,6-tetra-O-galloyl-beta-D-glucose (16), were evaluated for the inhibitory activity against chitin synthase II and III. They inhibited chitin synthase II with IC(50) values of 18-206 microM, except for two organic acids, (-)-quinic acid (8) and (-)-shikimic acid (9). Among them, 3-O-galloyl-(-)-shikimic acid (3) was the most potent inhibitor against chitin synthase II of Saccharomyces cerevisiae with an IC(50) value of 18 microM. The inhibition appears to be selective for chitin synthase II, as they did not appreciably inhibit chitin synthase III.

MAGE-E1, a new member of the melanoma-associated antigen gene family and its expression in human glioma

To unearth glioma-specific genes in human glioblastoma, the serial analysis of gene expression technique was applied to a primary glioblastoma, using cultured human astrocytes as a normal control. Among the top 147 most-expressed tags in glioblastoma, we found a tag, TTTTGGGTAT, that originated from an unidentified gene and which was not detected in human astrocyte cultures. Real-time quantitative reverse transcription-PCR showed that MAGE-E1 expression was 2.6-15-fold enriched in glioblastoma relative to human astrocytes. Expressed sequence tags containing this tag were homologous to the melanoma-associated antigen gene (MAGE) family, and this new cDNA, named MAGE-E1, was cloned by the 5'-rapid amplification of cDNA ends technique. Three alternatively spliced variants (MAGE-E1a-c) were found, and deduced amino acid sequence showed that MAGE-E1a and -E1b shared the MAGE-conserved region, whereas -E1c did not. This suggests that although MAGE-E1c is expressed from one of the MAGE family, it has distinct functions from other members. Tissue distribution analysis showed that MAGE-E1 was distinct from other MAGEs. MAGE-E1 expression was detected only in brain and ovary among normal tissues. Interestingly, MAGE-E1a and/or -E1b were specifically expressed in glioma cells among cancer cells. These results indicate that MAGE-E1 is a novel and glioma-specific member of MAGE family.

Pathogenic significance of neuronal migration disorders in temporal lobe epilepsy

To assess the epileptogenic lesions, a series of 202 cases with temporal lobectomy were analyzed histopathologically. The severity of hippocampal neuronal loss in patients with temporal lobe epilepsy was quantitatively analyzed and compared against autopsy controls of patients who died of nonneurologic disorders. For the histopathologic diagnosis of neuronal migration disorder (NMD), immunohistochemical stains for neurofilament protein (NF-M/H) and microtubule-associated protein 2 (MAP2) and Bielschowsky silver stains were routinely performed. Histopathology of NMD was classified by the 4-grade system. MAP2 immunoreactivity was useful in the identification of loss of normal polarization of dendrites in the abnormal neurons. NF-M/H immunohistochemistry and silver stains effectively labeled microscopic or occult lesions of NMD (grade II and III). Ammon hom sclerosis (AHS) was identified in 73.3% and NMD in 57.9%. There was more than 50% neuronal cell loss in 82.8% of AHS, and variable degrees of cell loss were observed in the dual-pathology groups. The frequency of dual pathology (both AHS and NMD) was 65.0% and showed relatively equal distributions in grades I, II, III, whereas the pure NMD group were classified predominantly as grades II and III. NMD might be a basic pathogenic substrate causing temporal lobe epilepsy. The dual pathology may indicate the presence of epileptogenic lesions in the neocortical and temporolimbic areas.

Antifungal activity of modified hederagenin glycosides from the leaves of Kalopanax pictum var. chinense

Monodesmosides which were obtained from the partial degradation of hederagenin bisdesmosides exhibited significant antifungal effect against Microsporum canis, Coccidioides immitis, Trichophyton mentagrophytes, Cryptococcus neoformans, and Candida albicans at the minimal inhibitory concentrations of 6.25-25 microg/ml. The hederagenin glycosides were isolated from the leaves of Kalopanax pictum var. chinense.

Cleavage of Bax is mediated by caspase-dependent or -independent calpain activation in dopaminergic neuronal cells: protective role of Bcl-2

Two cysteine protease families, caspase and calpain, are known to participate in cell death. We investigated whether a stress-specific protease activation pathway exists, and to what extent Bcl-2 plays a role in preventing drug-induced protease activity and cell death in a dopaminergic neuronal cell line, MN9D. Staurosporine (STS) induced caspase-dependent apoptosis while a dopaminergic neurotoxin, MPP(+) largely induced caspase-independent necrotic cell death as determined by morphological and biochemical criteria including cytochrome c release and fluorogenic caspase cleavage assay. At the late stage of both STS- and MPP(+)-induced cell death, Bax was cleaved into an 18-kDa fragment. This 18-kDa fragment appeared only in the mitochondria-enriched heavy membrane fraction of STS-treated cells, whereas it was detected exclusively in the cytosolic fraction of MPP(+)-treated cells. This proteolytic cleavage of Bax appeared to be mediated by calpain as determined by incubation with [(35)S]methionine-labelled Bax. Thus, cotreatment of cells with calpain inhibitor blocked both MPP(+)- and STS-induced Bax cleavage. Intriguingly, overexpression of baculovirus-derived inhibiting protein of caspase, p35 or cotreatment of cells with caspase inhibitor blocked STS- but not MPP(+)-induced Bax cleavage. This appears to indicate that calpain activation may be either dependent or independent of caspase activation within the same cells. However, cotreatment with calpain inhibitor rescued cells from MPP(+)-induced but not from STS-induced neuronal cell death. In these paradigms of dopaminergic cell death, overexpression of Bcl-2 prevented both STS- and MPP(+)-induced cell death and its associated cleavage of Bax. Thus, our results suggest that Bcl-2 may play a protective role by primarily blocking drug-induced caspase or calpain activity in dopaminergic neuronal cells.

Mitogen‐activated protein kinase signalling in oligodendrocytes: a comparison of primary cultures and CG‐4

Oligodendrocytes play a significant role in the central nervous system, as these cells are responsible for myelinating axons and allowing for the efficient conduction of nerve impulses. Therefore, any understanding we can gain about the functional biology of oligodendrocytes will give us important insights into demyelinating diseases such as multiple sclerosis, where oligodendrocytes and myelin are damaged or destroyed. Currently, much attention has focussed on the role of a family of mitogen-activated protein kinases in OL. This kinase family includes the extracellular signal-regulated protein kinases (ERKs), the stress-activated c-Jun N-terminal kinase (JNK), and the 38 kDa high osmolarity glycerol response kinase (p38). The actions of mitogen-activated protein kinases in oligodendrocytes appear to range from proliferation and cell survival to differentiation and cell death. In the past, studies on oligodendrocytes have been hampered by the difficulties inherent in producing large enough quantities of these cells for experimentation. This problem arises in large part due to the post-mitotic nature of mature oligodendrocytes. Over the years, a cell line known as Central Glia-4 (CG-4) has become a popular oligodendrocyte model due to its potentially unlimited capacity for self-renewal. In this review, we will look at the suitability of the Central Glia-4 cell line as an oligodendrocyte model, specifically in respect to studies on mitogen-activated protein kinase signalling in oligodendrocytes.

Zn(2+) induces stimulation of the c-Jun N-terminal kinase signaling pathway through phosphoinositide 3-Kinase

Zn(2+), one of the most abundant trace metal ions in mammalian cells, modulates the functions of many regulatory proteins associated with a variety of cellular activities. In the central nervous system, Zn(2+) is highly localized in the cerebral cortex and hippocampus. It has been proposed to play a role in normal brain function as well as in the pathophysiology of certain neurodegenerative disorders. We here report that Zn(2+) induced stimulation of the c-Jun N-terminal kinase (JNK) pathway in mouse primary cortical cells and in various cell lines. Exposure of cells to Zn(2+) resulted in the stimulation of JNK and its upstream kinases including stress-activated protein kinase kinase and mitogen-activated protein kinase kinase kinase. Zn(2+) also induced stimulation of phosphoinositide 3-kinase (PI3K) The Zn(2+)-induced JNK stimulation was blocked by LY294002, a PI3K inhibitor, or by a dominant-negative mutant of PI3Kgamma. Furthermore, overexpression of Rac1N17, a dominant negative mutant of Rac1, suppressed the Zn(2+)- and PI3Kgamma-induced JNK stimulation. The stimulatory effect of Zn(2+) on both PI3K and JNK was repressed by the free-radical scavenging agent N-acetylcysteine. Taken together, our data suggest that Zn(2+) induces stimulation of the JNK signaling pathway through PI3K-Rac1 signals and that the free-radical generation may be an important step in the Zn(2+) induction of the JNK stimulation.

Neuroprotective effects of estrogen against beta-amyloid toxicity are mediated by estrogen receptors in cultured neuronal cells

Although estrogen is known to exert beneficial effects on Alzheimer's disease, its underlying cellular mechanisms have not been clear. In this study we investigated whether or not neuroprotective effects of estrogen are mediated by estrogen receptors (ERs). Treatment of estrogen (1.8 nM) reduced beta-amyloid (Abeta)-induced death of ER-expressing W4 cells. This effect of estrogen was blocked by a specific ER blocker ICI 182,780. When estrogen was treated to HT22 cells, which lack functional ERs, Abeta-induced cell death was not affected. Transfection of HT22 cells with human ERalpha, but not ERbeta, restored protective action of estrogen against Abeta. Hoechst staining revealed that estrogen protected ERalpha-expressing cells by blocking Abeta-induced apoptosis. These results indicate that estrogen blocks Abeta-induced cell death via ERalpha-dependent pathways.