Protopanaxatriol inhibits melanin synthesis through inactivation of the pCREB-MITF-tyrosinase signalling pathway in melanocytes.

Ginsenosides are major active components of ginseng, and have diverse pharmacological properties in traditional medicine. Recent reports have shown that ginsenosides modify skin physiology and mitigate skin disorders such as photoageing and hyperpigmentation. We evaluated the antimelanogenic efficacy of protopanaxatriol, a major category of ginsenosides, as a depigmenting agent. Protopanaxatriol significantly reduced intracellular and extracellular melanin content in a concentration-dependent manner in B16 melanoma cells treated with α-melanocyte-stimulating hormone. In normal human epidermal melanocytes, protopanaxatriol clearly decreased melanin synthesis and dendrite elongation. In addition, protopanaxatriol dramatically suppressed the expression of genes encoding the melanogenic proteins tyrosinase, tyrosinase-related protein-1 and -2, and microphthalmia-associated transcription factor through dephosphorylation of cAMP response element-binding protein. These results suggest that protopanaxatriol could be an effective candidate anti-melanogenic agent.

Viral activity and outcome of hepatitis B surface antigen-positive grafts in deceased liver transplantation.

Indications of liver transplantation are extensive, but deceased donation does not meet the demand. Hepatitis B surface antigen (HBsAg)-positive grafts used to be discarded in the past. The aim of this study was to examine viral activity and outcome of HBsAg-positive deceased grafts transplanted to HBsAg-positive recipients. Eleven HBsAg-positive deceased grafts were transplanted to HBsAg-positive patients with acute liver failure (3 patients), hepatocellular carcinoma (6 patients) and repeatedly bleeding varices (2 patients). Postoperatively, hepatitis B virus (HBV) infection was treated by a combination of antiviral nucleoside and nucleotide analogues. HBV DNA and HBsAg were measured periodically. The median (interquartile) model of end-stage liver disease score for the recipients was 19 (16-32) with a range from 11 to 40. HBV DNA was detected in 6 patients with a range from 61 to 1083 IU/mL before transplantation. After transplantation, HBV DNA was detected in 4 patients in the first month and 2 patients in the 6th month and became undetectable for all patients at end of the first year. The quantitative HBsAg ranged from 0.86 to 241.1 IU/mL at 6 months and 0.34 to 238.5 IU/mL at 24 months (P = .135). Three of the patients died in the early phase, and the other patients were followed up for 40.0 ± 19.2 months with normal liver function. In conclusion, HBsAg-positive deceased liver grafts function well with minimal viral activity under treatment of combined antiviral nucleoside and nucleotide analogues. Use of HBsAg-positive deceased grafts is feasible and increases the donor pool to rescue dying patients.

Do stillbirth, miscarriage, and termination of pregnancy increase risks of attempted and completed suicide within a year? A population-based nested case-control study.

OBJECTIVE: To investigate the risks of attempted and completed suicide in women who experienced a stillbirth, miscarriage, or termination of pregnancy within 1 year postnatally and compare this risk with that in women who experienced a live birth. DESIGN: A nested case-control study. SETTING: Linking three nationwide population-based data sets in Taiwan: the National Health Insurance Research Database, the National Birth Registry and the National Death Registry. SAMPLE: In all, 485 and 350 cases of attempted and completed suicide, respectively, were identified during 2001-11; for each case, ten controls were randomly selected and matched to the cases according to the age and year of delivery. METHODS: Conditional logistic regression. MAIN OUTCOME MEASURES: Attempted and completed suicidal statuses were determined. RESULTS: The rates of attempted suicide increased in the women who experienced fetal loss. The risk of completed suicide was higher in women who experienced a stillbirth [adjusted odds ratio (aOR) 5.2; 95% CI 1.77-15.32], miscarriage (aOR 3.81; 95% CI 2.81-5.15), or termination of pregnancy (aOR 3.12; 95% CI 1.77-5.5) than in those who had a live birth. Furthermore, the risk of attempted suicide was significantly higher in women who experienced a miscarriage (aOR 2.1; 95% CI 1.66-2.65) or termination of pregnancy (aOR 2.5; 95% CI 1.63-3.82). In addition to marital and educational statuses, psychological illness increased the risk of suicidal behaviour. CONCLUSIONS: The risk of suicide might increase in women who experience fetal loss within 1 year postnatally. Healthcare professionals and family members should enhance their sensitivity to care for possible mental distress, particularly for women who have experienced a stillbirth. TWEETABLE ABSTRACT: Suicide risk increased in women who had a stillbirth, miscarriage, or termination of pregnancy within 1 year postnatally.

Increased 8-hydroxy-2'-deoxyguanosine in plasma and decreased mRNA expression of human 8-oxoguanine DNA glycosylase 1, anti-oxidant enzymes, mitochondrial biogenesis-related proteins and glycolytic enzymes in leucocytes in patients with systemic lupus erythematosus.

We measured plasma levels of the oxidative DNA damage marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) and leucocyte mRNA expression levels of the genes encoding the 8-OHdG repair enzyme human 8-oxoguanine DNA glycosylase 1 (hOGG1), the anti-oxidant enzymes copper/zinc superoxide dismutase (Cu/ZnSOD), manganese superoxide dismutase (MnSOD), catalase, glutathione peroxidase-1 (GPx-1), GPx-4, glutathione reductase (GR) and glutathione synthetase (GS), the mitochondrial biogenesis-related proteins mtDNA-encoded ND 1 polypeptide (ND1), ND6, ATPase 6, mitochondrial transcription factor A (Tfam), nuclear respiratory factor 1(NRF-1), pyruvate dehydrogenase E1 component alpha subunit (PDHA1), pyruvate dehydrogenase kinase isoenzyme 1 (PDK-1) and hypoxia inducible factor-1α (HIF-1α) and the glycolytic enzymes hexokinase-II (HK-II), glucose 6-phosphate isomerase (GPI), phosphofructokinase (PFK), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and lactate dehydrogenase A (LDHa). We analysed their relevance to oxidative damage in 85 systemic lupus erythematosus (SLE) patients, four complicated SLE patients undergoing rituximab treatment and 45 healthy individuals. SLE patients had higher plasma 8-OHdG levels (P < 0·01) but lower leucocyte expression of the genes encoding hOGG1(P < 0·01), anti-oxidant enzymes (P < 0·05), mitochondrial biogenesis-related proteins (P < 0·05) and glycolytic enzymes (P < 0·05) than healthy individuals. The increase in plasma 8-OHdG was correlated positively with the elevation of leucocyte expression of the genes encoding hOGG1 (P < 0·05), anti-oxidant enzymes (P < 0·05), several mitochondrial biogenesis-related proteins (P < 0·05) and glycolytic enzymes (P < 0·05) in lupus patients. The patients, whose leucocyte mtDNA harboured D310 heteroplasmy, exhibited a positive correlation between the mtDNA copy number and expression of ND1, ND6 and ATPase 6 (P < 0·05) and a negative correlation between mtDNA copy number and systemic lupus erythematosus disease activity index (SLEDAI) (P < 0·05), as well as plasma 8-OHdG (P < 0·05). In particular, four complicated SLE patients with increased expression of the genes encoding the anti-oxidant enzymes, GAPDH, Tfam and PDHA1, experienced better therapeutic outcomes after rituximab therapy. In conclusion, higher oxidative damage with suboptimal increases in DNA repair, anti-oxidant capacity, mitochondrial biogenesis and glucose metabolism may be implicated in SLE deterioration, and this impairment might be improved by targeted biological therapy.

The usefulness of arbekacin compared to vancomycin.

The bacteriological efficacy response (improved, arbekacin vs. vancomycin; 71.2% vs. 79.5%) and clinical efficacy response (improved, arbekacin vs. vancomycin; 65.3% vs. 76.1%) were not statistically different between the two groups. The complication rate was significantly higher in the vancomycin group (32.9%) compared to the arbekacin group (15.1%) (p=0.019). Arbekacin was not inferior to vancomycin, and it could be a good alternative drug for vancomycin in methicillin-resistant Staphylococcus aureus (MRSA) treatment.

Nafamostat mesilate attenuates Postreperfusion Syndrome during liver transplantation.

Postreperfusion syndrome (PRS), an acute decrease in blood pressure after reperfusion of the liver graft, occurs frequently during liver transplantation surgery. We supposed that the activation of the kallikrein-kinin system leading to extensive systemic vasodilatation was a possible cause. The effect of pretreatment with nafamostat mesilate (NM), a broad spectrum serine protease inhibitor, on the occurrence of PRS was evaluated. Sixty-two adult liver recipients were randomized to receive an intravenous bolus of either 0.02 mg/kg of NM (NM group, n = 31) or an equal volume of normal saline (control group, n = 31) just before reperfusion of the liver graft. Occurrence of PRS and intraoperative use of vasoactive drugs were compared between the two groups. Postoperative recovery was also compared. PRS was significantly less frequent (48% vs. 81%, p = 0.016) requiring less vasopressors in the NM group compared to the control group. The NM group also showed faster recovery of the mean arterial pressure. Perioperative laboratory values were similar between the two groups. Pretreatment with 0.02 mg/kg of NM immediately before reperfusion decreases the frequency of PRS and vasopressor requirements during the reperfusion period in liver transplantation.

Indicators and outcome of liver transplantation in acute liver decompensation after flares of hepatitis B.

Non-cirrhotic patients having acute liver decompensation in flares of hepatitis B can recover spontaneously or die without liver transplantation. Criteria for identifying patients in need of liver transplantation are lacking. Fifty-one non-cirrhotic patients having acute liver decompensation in flares of hepatitis B were retrospectively reviewed. The patients were divided into three groups: group A patients (n=18) recovered from acute liver decompensation spontaneously; group B patients (n=22) died of acute liver failure; and group C patients (n=11) had liver transplantation. Model of end-stage liver disease (MELD) scores were evaluated to identify the criteria for liver transplantation. The cut-off point of MELD scores for liver transplantation was evaluated by receiver operating characteristic (ROC) curve. Comparing group A and B patients, MELD score was an independent factor to predict prognosis. By analysing ROC curve, a MELD score>30 was the most optimal cut-off point to indicate liver transplantation; however, the false positive rate was 11.1%. By weekly measurement of MELD scores, subsequent increase in MELD scores could help to avoid false positives. Moreover, a MELD score>34 yielded 0% false positive rate and indicated the necessity of definite liver transplantation. For group C patients, ten of 11 patients were saved by liver transplantation. In conclusion, for the patients having acute liver decompensation in flares of hepatitis B, liver transplantation is definitely indicated by MELD scores>34. Liver transplantation is also indicated if the MELD score increases in the subsequent 1-2 weeks. Liver transplantation has a good outcome if performed on time.

2009 H1N1 influenza infection in Korean healthcare personnel.

Healthcare personnel (HCP) can acquire influenza and transmit it to patients and other hospital staff. The aim of this study was to evaluate the attack rate of HCP by the 2009 H1N1 influenza virus during the 2009 pandemic influenza season in Korea. HCP infected with H1N1 virus were asked to fill out a questionnaire, which included job type, method of diagnosis, facility type, history of contact with patients infected by H1N1 virus, vaccination status, and use of personal protective equipment. A total of 328 HCP (female 68.6%, 225/328) were infected with H1N1 virus at the nine study centers. The highest attack rate was in physicians, followed by nurses and nurses' aides. Transmission occurred primarily after contact with outpatients (27.8%), followed by contact with inpatients (21.6%). Most (77.3%) of the infected HCP never used an N95 mask during contact with patients. Surgical masks were always used by 29.4% of the subjects and usually or intermittent used by 46.9%. The peak incidence of the H1N1 infection among HCP preceded that among the general population. Among HCPs, physicians, nurses, and nurses' aides were at the greatest risk of H1N1 infection. HCP should be more vigilant and protect themselves with appropriate personal protective equipment during the influenza season.

Monitoring of viruses in chum salmon (Oncorhynchus keta) migrating to Korea.

It is important to investigate the prevalence of salmonid pathogens because they can affect the amount of release of salmonid fry and the migration rate of adult salmonids. In this study, routine surveys were conducted for investigating virus distribution in migrating chum salmon spawners (Oncorhynchus keta) and their offsprings at the Namdae River, Yangyang, Korea, during 2006-2008. Anterior kidneys were removed from chum salmon spawner individuals, homogenized with minimal essential medium, and centrifuged to make supernatants for conducting RT-PCR. Five offspring were pooled to for conducting RT-PCR. Infectious pancreatic necrosis virus (IPNV), infectious hematopoietic necrosis virus (IHNV) and viral hemorrhagic septicemia virus (VHSV) were the target viruses for monitoring. In 2006, only spawners were investigated, and 27.5% of fish (22/80) were found to be IHNV-positive by nested PCR. In 2007, 65.6% of pooled fry (21/32) were IHNV-positive, and 9.4% (3/32) were IPNV-positive by one-step PCR. When nested PCR was conducted, 84.4% (27/32) were IHNV-positive, and 28.1% (9/32) were IPNV-positive. However, only 1.3% of spawners (1/80) were IHNV-positive by nested PCR. In 2008, 25% (8/32) of pooled fry were IHNV-positive by one-step PCR, but 59.4% (19/32) were IHNV-positive and 12.5% (4/32) were IPNV-positive by nested PCR. All of the samples tested were VHSV-negative. Although all viruses detected in this study were from chum salmon, phylogenetic analysis showed that they possibly originated from rainbow trout or clustered with the rainbow trout isolates. More extensive long-term studies are needed to clarify the origins of these viruses and their potential effects on chum salmon migration in Korea.

DLEC1 and MLH1 promoter methylation are associated with poor prognosis in non-small cell lung carcinoma.

The significance of chromosome 3p gene alterations in lung cancer is poorly understood. This study set out to investigate promoter methylation in the deleted in lung and oesophageal cancer 1 (DLEC1), MLH1 and other 3p genes in 239 non-small cell lung carcinomas (NSCLC). DLEC1 was methylated in 38.7%, MLH1 in 35.7%, RARbeta in 51.7%, RASSF1A in 32.4% and BLU in 35.3% of tumours. Any two of the gene alterations were associated with each other except RARbeta. DLEC1 methylation was an independent marker of poor survival in the whole cohort (P=0.025) and in squamous cell carcinoma (P=0.041). MLH1 methylation was also prognostic, particularly in large cell cancer (P=0.006). Concordant methylation of DLEC1/MLH1 was the strongest independent indicator of poor prognosis in the whole cohort (P=0.009). However, microsatellite instability and loss of MLH1 expression was rare, suggesting that MLH1 promoter methylation does not usually lead to gene silencing in lung cancer. This is the first study describing the prognostic value of DLEC1 and MLH1 methylation in NSCLC. The concordant methylation is possibly a consequence of a long-range epigenetic effect in this region of chromosome 3p, which has recently been described in other cancers.

Elevated serum decoy receptor 3 with enhanced T cell activation in systemic lupus erythematosus.

Decoy receptor 3 (DcR3/TR6) is a decoy receptor for the Fas ligand (FasL) and can inhibit FasL-induced apoptosis. It has been reported recently that DcR3 can induce T cell activation via co-stimulation of T cells, suggesting that DcR3 may be involved in the pathophysiology of autoimmune diseases. This study aims to analyse the serum DcR3 in patients with systemic lupus erythematosus (SLE) and to investigate the role of DcR3 in the pathogenesis of SLE. Significantly elevated serum DcR3 was observed in SLE patients, and the mean serum DcR3 level was significantly higher for those with active disease [SLE disease activity index (SLEDAI) >/= 10] compared with that in patients with inactive disease (SLEDAI < 10). In addition to reducing activation-induced cell death in activated T cells via neutralization of the FasL, soluble DcR3-Fc enhanced T cell proliferation and increased interleukin-2 and interferon-gamma production via co-stimulation of T cells. Moreover, enhanced T cell reactivity to DcR3-induced co-stimulation was demonstrated in lymphocytes from patients with SLE, suggesting the elevated serum DcR3 may associate with enhanced T cell activation in vivo. These findings are the first to demonstrate that serum DcR3 concentrations are increased in SLE patients, and this may imply a possible role of DcR3 in the pathogenesis of SLE via enhanced T cell hyperreactivity and reduced apoptosis in activated T cells.

Prognostic significance of DNA repair proteins MLH1, MSH2 and MGMT expression in non-small-cell lung cancer and precursor lesions.

AIMS: To investigate the role of DNA repair proteins and their prognostic significance in non-small-cell lung cancer (NSCLC). METHODS AND RESULTS: A retrospective analysis of 108 cases of stage I-II NSCLC was undertaken. Immunohistochemical expression of DNA repair proteins MLH1, MSH2 and MGMT was assessed using tissue microarrays of paraffin-embedded samples of invasive carcinoma and precursor lesions. Results were analysed in relation to clinicopathological parameters and patient survival. Reduced expression of MLH1 was found in 58.5% of tumours and occurred less frequently in poorly differentiated tumours (P = 0.044) and large cell carcinomas (P = 0.004). MSH2 and MGMT expression was reduced in 18.1% and 77.8% of cases, respectively. There was an inverse relationship between MLH1 and MSH2 expression (P = 0.012). Normal expression of MLH1, MSH2 and MGMT was found in all cases of squamous metaplasia and squamous dysplasia. Only a single case of carcinoma in situ (12.5%) showed reduced MLH1, none showed reduced MSH2 and 25% showed reduced MGMT. Survival analyses showed no prognostic significance based on expression of MLH1 (P = 0.92), MSH2 (P = 0.78) or MGMT (P = 0.57). CONCLUSIONS: Reduction in expression of DNA repair proteins MLH1, MSH2 and MGMT is relatively common in NSCLC, appears to be a late event in the development of invasive malignancy and does not influence survival in this patient cohort.

Endoscopic management of biliary complications after adult right-lobe living donor liver transplantation without initial biliary decompression.

OBJECTIVES: We sought to examine biliary complications in adult right-lobe living donor liver transplantation (LDLT) with duct-to-duct anastomosis (RL-LDLT-DD), evaluating the efficacy of endoscopic retrograde cholangiography (ERC) in the diagnosis and management of biliary complications following LDLT. METHODS: Ninety adult RL-LDLT-DD were performed from June 2004 to August 2007, including 21 (23.3%) cases of biliary complications. RESULTS: The endoscopic retrograde cholangiopancreatiography (ERCP) findings were stricture only (n = 8), stricture plus leakage (n = 9), and leakage only (n = 4). In the overall 13 cases of leakage, nine patients recovered after treatment by stent or endoscopic nasobiliary drainage. The time to resolution was 3.0 +/- 1.3 months with 2.2 +/- 1.3 endoscopic examinations. All bile duct complications were treated by ERC first. Among 17 cases with stricture, seven cases were successfully treated by endoscopy and three cases by percutaneous transhepatic cholangiography plus stent (PTCS). In the other seven cases, the treatment was still ongoing in five cases and two subjects died during treatment. The mean time to stricture resolution 7.2 +/- 3.3 months with 3.9 +/- 1.4 endoscopic examinations. The results of 21 cases were 5/21 mortalities (23.8%), successful ERC treatment in 9/21; (42.9%), successful PTCS treatment in 3/21 (14.3%), and ongoing ERC treatment in 5/21, (23.8%), including one case with successful ERC treatment who died of lung infection postoperatively. During follow-up (13.1 +/- 9.9 months), there was no recurrence in the stricture or leak. CONCLUSIONS: When compared with the literature, RL-LDLT-DD without biliary drainage does not increase the incidence of biliary complications. From our study, ERC and PTC play a complementary roles in the treatment of bile duct complications.

Effect of ozone oxidation on single-walled carbon nanotubes.

Exposing single-walled carbon nanotubes to room-temperature UV-generated ozone leads to an irreversible increase in their electrical resistance. We demonstrate that the increased resistance is due to ozone oxidation on the sidewalls of the nanotubes rather than at the end caps. Raman and X-ray photoelectron spectroscopies show an increase in the defect density due to the oxidation of the nanotubes. Using ultraviolet photoelectron spectroscopy, we show that these defects represent the removal of pi-conjugated electron states near the Fermi level, leading to the observed increase in electrical resistance. Oxidation of carbon nanotubes is an important first step in many chemical functionalization processes. Because the oxidation rate can be controlled with short exposures, UV-generated ozone offers the potential for use as a low-thermal-budget processing tool.

Outcome of inappropriate empirical antibiotic therapy in patients with Staphylococcus aureus bacteraemia: analytical strategy using propensity scores.

Patients with Staphylococcus aureus bacteraemia (SAB) who received either inappropriate or appropriate empirical therapy were compared by using two risk stratification models: (1) a cohort study using a propensity score to adjust for confounding by empirical treatment assignment; and (2) a propensity-matched case-control study. Inappropriate empirical therapy was modelled on the basis of patient characteristics, and included in the multivariate model to adjust for confounding. For case-matching analysis, patients with inappropriate empirical therapy (cases) were matched to those with appropriate empirical therapy (controls) on the basis of the propensity score (within 0.03 on a scale of 0-1). In total, 238 patients with SAB were enrolled in the cohort study. Characteristics associated with inappropriate empirical therapy were methicillin resistance, underlying haematological malignancy, no history of colonisation with methicillin-resistant S. aureus, and a long hospital stay before SAB. These variables were included in the propensity score, which had an area under the receiver operating characteristics curve of 85%. In the cohort study, SAB-related mortality was 39% (45/117) for inappropriate empirical therapy vs. 28% (34/121) for appropriate empirical therapy (odds ratio (OR) 1.60; 95% CI 0.93-2.76). After adjustment for independent predictors for mortality and the propensity score, inappropriate empirical therapy was not associated with mortality (adjusted OR 1.39; 95% CI 0.62-3.15). In the matched case-control study (50 pairs), SAB-related mortality was 32% (16/50) for inappropriate empirical therapy and 28% (14/50) for appropriate empirical therapy (McNemar's test; p 0.85; OR 1.15; 95% CI 0.51-2.64). In conclusion, inappropriate empirical therapy resulted in only a slight tendency towards increased mortality in patients with SAB.

Room-temperature imprinting method for plastic microchannel fabrication

A new plastic imprinting method using a silicon template is demonstrated. This new approach obviates the necessity of heating the plastic substrate during the stamping process, thus improving the device yield from approximately 10 devices to above 100 devices per template. The dimensions of the imprinted microchannels were found to be very reproducible, with variations of less than 2%. The channel depths were dependent on the pressures applied and the materials used. Rather than bonding the open channels with another piece of plastic, a flexible and adhesive poly(dimethylsiloxane) film is used to seal the microchannels, which offers many advantages. As an application, isoelectric focusing of green fluorescence protein on these plastic microfluidic devices is illustrated.

Neocortical neurons cultured from mice with expanded CAG repeats in the huntingtin gene: unaltered vulnerability to excitotoxins and other insults.

Glutamate-mediated excitotoxicity might contribute to the pathogenesis of Huntington's disease and other polyglutamine repeat disorders. We used murine neocortical cultures derived from transgenic and knock-in mice to test the effect of expression of expanded polyglutamine-containing huntingtin on neuronal vulnerability to excitotoxins or other insults. Neurons cultured from mice expressing either a normal length (Hdh(Q20)) or expanded (Hdh(Q111)) CAG repeat as a knock-in genetic alteration in exon one of the mouse Hdh gene [Hum Mol Genet 8 (1999) 115] had similar vulnerability to N-methyl-D-aspartate (NMDA) and kainate-mediated excitotoxicity. These neurons also exhibited similar vulnerability to oxidative stress (24 h exposure to 10-100 microM paraquat or 1-10 microM menadione), apoptosis (48 h exposure to 30-100 nM staurosporine or 1 microM dizocilpine maleate (MK-801) and proteasome inhibition (48 h exposure to 0.3-3 microM MG-132). Neocortical neurons cultured from mice transgenic for an expanded CAG repeat-containing exon 1 of the human HD gene (Mangiarini et al., 1996, R6/2 line) and non-transgenic littermate controls also had similar vulnerability to NMDA and kainate-mediated excitotoxicity. These observations suggest that expression of expanded polyglutamine-containing huntingtin does not acutely alter the vulnerability of cortical neurons to excitotoxic, oxidative or apoptotic insults.

Guiding neutral atoms on a chip

We demonstrate the guiding of neutral atoms by the magnetic fields due to microfabricated current-carrying wires on a chip. Atoms are guided along a magnetic field minimum parallel to and above the current-carrying wires. Two guide configurations are demonstrated: one using two wires with an external magnetic field, and a second using four wires without an external field. These guide geometries can be extended to integrated atom optics circuits, including beam splitters.

Mode of Inhibition of Transient Outward Current by 1-Benzyl-1,2,3,4-Tetrahydroisoquinoline in Rat Ventricular Cells.

In this study, we examined the effects of 1-benzyl-1,2,3,4-tetrahydroisoquinoline (S49) on a transient outward current (I(to)) in rat ventricular myocytes using the whole-cell patch-clamp technique. Depolarization of ventricular myocytes not only activated I(to), but sustained outward currents as well. S49 dose-dependently inhibited the amplitude or integral of I(to), with a 50% inhibitory concentration (IC(50)) of 4.3 and 2.7 &mgr;M, respectively. The inhibition of I(to) by S49 was associated with an acceleration of I(to) decay. However, S49 had no effect on half inactivation voltage (V(0.5)) and slope factor of the voltage-dependent steady-state inactivation curve of I(to). Time-course analysis revealed that S49 developed a block during the depolarizing voltage-clamp step in a monoexponential manner. The rate and magnitude of block were concentration dependent. The equilibrium dissociation constant (K(d)) used to inhibit I(to) induced by S49, as calculated from the time constant of developing block, was 3.4 &mgr;M. The time constant of recovery of I(to) from the inactivation state was prolonged by S49. Following treatment with quinidine, the process of I(to) recovery was divided into rapid and extremely slow recovery components. Also, the relief from quinidine- or S49-induced block was assessed by comparing the recovery processes of I(to) with or without drugs. That comparison revealed the relief from the block of I(to) channels by S49 to be more rapid. In summary, the inhibition of I(to) by S49 was dose dependent, time dependent but voltage independent. The mechanisms of action might be an open-state block. Copyright 1996 S. Karger AG, Basel

Association of CTLA4 gene A-G polymorphism with rheumatoid arthritis in Chinese.

The aim of this study was to investigate the allelic association of a single nucleotide polymorphism in exon 1 of the cytotoxic T-lymphocyte antigen-4 (CTLA4) gene with rheumatoid arthritis (RA) in Chinese people. One hundred and eighty-six unrelated adults with RA and 203 randomly selected normal adults were studied. All were ethnic Chinese living in Taiwan. The CTLA4 A-G polymorphism was genotyped with a polymerase chain reaction (PCR) and digestion with the restriction enzyme BstEII. The genotype and allele frequencies of CTLA4 in patients with rheumatoid arthritis differed significantly from those of adult controls (P=0.022 and P=0.037, respectively). Genotype CTLA4 49 G/G and allele G were associated with an increased risk of RA (RR=1.72, 95% CI=1.15-2.57, P=0.008; RR=1.39, 95% CI=1.02-1.89, P=0.037, respectively), whereas genotype A/G and allele A were associated with protection against RA (RR=0.58, 95% CI=0.39-0.87, P=0.008 and RR=0.72, 95% CI=0.53-0.98, P=0.037, respectively). We concluded that, the CTLA4 49 A-G polymorphism is associated with RA in Chinese patients from Taiwan.