Inchworm bipedal nanowalker.

Nanowalkers take either inchworm (IW) or hand-over-hand (HOH) gait. The IW nanowalkers are advantageous over HOH ones in force generation, processivity and high-density integration, though both gaits occur in intracellular nanowalkers from biology. Artificial IW nanowalkers have been realized or proposed, but all rely on different 'head' and 'tail' to gain an adventitious direction. Here we report an inherently unidirectional IW nanowalker that is a biped with two identical legs (i.e., indistinguishable 'head' and 'tail'). This walker is made of DNA, and driven by a light-powered G-quadruplex engine. The directional inchworm motion is confirmed by operating the walker on a DNA duplex track that is designed to show a distinctive fluorescence pattern for IW walkers as compared to HOH ones. Interestingly, this walker exhibits stride-controlled IW-to-HOH gait switch and direction reversal when the track's periodic binding sites have wider and wider separation. The results altogether present an integrated mechanism for implementing nanowalkers of different gaits and directions on molecular tracks, optical potentials or even solid-state surfaces.

YM155 down-regulates survivin and XIAP, modulates autophagy and induces autophagy-dependent DNA damage in breast cancer cells.

BACKGROUND AND PURPOSE: The aim of this study was to determine the potency and molecular mechanism of action of YM155, a first-in-class survivin inhibitor that is currently under phase I/II clinical investigations, in various drug-resistant breast cancers including the oestrogen receptor positive (ER(+) ) tamoxifen-resistant breast cancer and the caspase-3-deficient breast cancer. EXPERIMENTAL APPROACH: The potency of YM155 in SK-BR-3, MDA-MB-231, MCF7 and its tamoxifen-resistant sublines, TamR6, TamR7, TamR8, TamC3 and TamC6, were determined by MTT assay. Western blot analysis, flow cytometric analysis, reverse transcription-PCR, fluorescent microscopy and comet assay were used to determine the molecular mechanism of action of YM155 in different breast cancer cell lines. KEY RESULTS: YM155 was equally potent towards the parental ER(+) /caspase-3-deficient MCF7 breast cancer cells and its tamoxifen-resistant sublines in vitro. The ER(-) /HER2(+) SK-BR-3 breast cancer cells and the triple-negative/caspase-3-expressing metastatic aggressive MDA-MB-231 breast cancer cells were also sensitive to YM155 with IC50 values in the low nanomolar range. Targeting survivin by YM155 modulated autophagy, induced autophagy-dependent caspase-7 activation and autophagy-dependent DNA damage in breast cancer cells. Interestingly, YM155 also induced XIAP degradation and the degradation of XIAP might play an important role in YM155-induced autophagy in breast cancer cells. CONCLUSIONS AND IMPLICATIONS: YM155 is a potent survivin inhibitor that has potential for the management of various breast cancer subtypes regardless of the expression of ER, HER2 and caspase-3. Importantly, this study provides new insights into YM155's molecular mechanism of action and therapeutic potential in the treatment of tamoxifen-resistant breast cancer.

Hepatitis C viral infection and the risk of dementia.

BACKGROUND AND PURPOSE: Hepatitis C virus (HCV) infection may cause cognitive impairment, but no studies have focused specifically on cognitive impairment stemming from HCV. The purpose of this study was to investigate the potential increased risk for dementia in HCV-infected patients. METHODS: A population-based cohort study based on the Taiwan National Health Insurance Research Database was conducted. From all potential participants aged 50 years or more, a total of 58,570 matched (1:1) pairs of HCV-infected patients and non-HCV-infected patients were included. Each subject was individually tracked from 1997 to 2009 to identify incident cases of dementia (onset in 1999 or later). Cox proportional hazards regressions were employed to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between HCV infection and dementia. RESULTS: There were 2989 dementia cases from the HCV-infected cohort during the follow-up period of 533,861.1 person-years; the overall incidence rates of dementia differed from the non-HCV cohort (56.0 vs. 47.7 cases per 10,000 person-years, P < 0.05). The adjusted HR for dementia was 1.36 (95% CI 1.27-1.42) for HCV-infected patients after adjusting for alcohol-related disease, liver cirrhosis, hepatic encephalopathy and hepatocellular carcinoma. CONCLUSIONS: HCV infection may increase the risk for dementia. Further mechanistic research is needed.

Poor response to 18-month lamivudine monotherapy in chronic hepatitis B patients with IgM anti-HBc and acute exacerbation.

BACKGROUND: Appearance of immunoglobulin class M antibody against hepatitis B core antigen is a predictor of beneficial response to interferon-alpha therapy in chronic hepatitis B patients, but its relationship with the efficacy of lamivudine therapy remains unclear. AIM: To investigate the outcome of lamivudine therapy in chronic hepatitis B patients with immunoglobulin class M antibody against hepatitis B core antigen and acute exacerbation. METHODS: Chronic hepatitis B patients with acute exacerbation receiving a national-wide therapeutic trial of 18-month lamivudine monotherapy were enrolled for the analysis. Four consecutive seronegative patients were recruited as individual matching controls of one positive subject. Immunoglobulin class M antibody against hepatitis B core antigen in serum was assayed monthly by an automated microparticle enzyme immunoassay. RESULTS: Fifteen (8.9%) of 167 chronic hepatitis B patients with acute exacerbation were seropositive for IgM anti-HBc. Thus 60 seronegative patients were consecutively recruited as control group. At the end of therapy, two (13.3%) of the 15 seropositive patients achieved a sustained response, significantly lower than 26 (43.3%) of the control group. CONCLUSIONS: Appearance of immunoglobulin class M antibody against hepatitis B core antigen in chronic hepatitis B patients with acute exacerbation is a predictor of poor response to lamivudine monotherapy. This is clinically relevant to the decision-making in treating chronic hepatitis B patients with acute exacerbation.

High frequency of functional anti-YMDD and -mutant cytotoxic T lymphocytes after in vitro expansion correlates with successful response to lamivudine therapy for chronic hepatitis B.

BACKGROUND: Many determinants for a sustained response to lamivudine therapy have been reported but the role of T cell responsiveness remains unclear. The finding that tyrosine-methionine-aspartate-aspartate (YMDD) motif of the reverse transcriptase domain of hepatitis B virus (HBV) DNA polymerase carries a HLA-A2 restricted cytotoxic T lymphocyte (CTL) epitope makes quantitative measurement of the numbers of peptide specific CTLs feasible using MHC tetramer-peptide complex staining. AIM: To investigate the correlation between anti-YMDD motif CTL activity and the efficacy of lamivudine therapy in HLA-A2 positive patients with chronic hepatitis B (CH-B). METHODS: The function and phenotype of peptide and interleukin 2 expanded peripheral blood mononuclear cells were quantified by cell lytic assay and immunocytochemical analysis by staining with HLA-A2-peptide tetramer complexes. RESULTS: After in vitro expansion, sustained responders had more potent CTL responses against YMDD, YVDD, and YIDD, as well as other epitopes on HBV antigens than non-responders. The frequency of YMDD/YVDD/YIDD motif specific CTLs increased significantly with an effective cell lytic function during and after therapy in sustained responders but not in non-responders. YMDD specific CTLs cross reacted with YIDD and YVDD mutant epitopes, and shared T cell receptor gene usages with YIDD and YVDD specific CTLs. CONCLUSIONS: Sustained responders, at least HLA-A2 patients, elicited a more potent CTL immunity against YMDD and its mutants. YMDD specific CTLs are cross reactive with YVDD and YIDD mutant epitopes, which may further contribute to immune clearance of the mutant viruses and a successful response to lamivudine therapy in CH-B patients.

A comparison of effectiveness and cost between two models of care for individuals with schizophrenia living in Taiwan.

Schizophrenia is a chronic disease that places tremendous costs and burden on patients, families, and communities. The purpose of this study was to compare the cost and effectiveness of a hospital-based home care model and a traditional community care model for schizophrenia in Taiwan using six principles of cost-effectiveness analysis. Based on the health care provider's analytic perspective, four effectiveness indicators and four service costs were identified and measured, and the ratio of average cost value to effectiveness score for each patient was calculated. According to that ratio, the hospital-based home care model was more cost-effective. The results suggest that the hospital-based outreach home care model is a cost-effective way to care for patients and their family in the community.

Apoptosis in viral hepatitis B and C.

Tumor necrosis factor (TNF) and TNF receptors (TNFR) are members of the growing TNF ligand and receptor families known to be involved in apoptosis, viral pathogenesis and immune regulation. The present report will focus on the role of apoptosis in the pathogenesis of viral hepatitis B and C. Although TNF was reported years ago to modulate viral infections, recent findings on the molecular pathways involved in TNFR signaling have allowed a better understanding of the molecular interactions between cellular and viral factors within the infected cell. The interactions of viral proteins with intracellular components downstream of the TNFR have highlighted at the molecular level that viruses can manipulate the cellular machinery to escape the immune surveillance and to favor spread infection. We will review here the mechanism of apoptosis and the role of viral proteins that regulate apoptosis in viral hepatitis B and C.

Modulation of tumor necrosis factor receptors 1 and 2 in chronic hepatitis B and C: the differences and implications in pathogenesis.

Tumor necrosis factor (TNF) plays a role in the pathogenesis of chronic hepatitis B (CHB) and chronic hepatitis C (CHC). The difference in the cytokine responses between hepatitis B virus (HBV) and hepatitis C virus (HCV) infections may have implications in the pathogenesis of these diseases. We performed a comparative study to examine the possible differences in the TNF-TNF receptor (TNFR) response between CHB and CHC. We studied the cytokine levels of 38 patients with CHB, 40 patients with CHC and 9 patients with dual hepatitis B and C, and compared them with the baseline levels of 12 healthy controls. The plasma levels of TNF-alpha, interferon-gamma, interleukin (IL)-2, IL-4, IL-10 and soluble TNFR-1 and 2 (sTNFR-1 and 2) were quantified by enzyme-linked immunosorbent assays. The expression of TNFR-1 and 2 in liver tissues was examined in 30 cases of CHB and 15 cases of CHC by semiquantitative reverse transcription polymerase chain reaction. The results showed that sTNFR-1 levels correlated with liver inflammation in all patients, whereas this correlation was not found with sTNFR-2 or other cytokines. Liver inflammation indicators were higher in HCV RNA+ than in HCV RNA- CHC. Most significantly, sTNFR-1 levels correlated with liver inflammation in CHB, but not in CHC. However, the expression of TNFR-1 and 2 in liver was similar between CHB and CHC. These findings suggest that the TNFR signal transduction pathway is modulated differently in HBV and HCV infection.

Impact of acute hepatitis B virus superinfection on chronic hepatitis C virus infection.

Hepatitis B virus (HBV) and hepatitis C virus (HCV) dual infection is not uncommon, but the impact of acute HBV superinfection in patients with chronic HCV infection is still unknown. Two patients with well documented chronic HCV infection were hospitalized for acute hepatitis, which was serologically confirmed to be acute HBV superinfection. One patient who was seropositive for both HBV-DNA and HCV-RNA upon admission died of hepatic failure. The other became seronegative for HCV-RNA and recovered with alanine aminotransferase normalization, seroclearance of HBsAg, and antibodies to HCV. These findings confirm that acute superinfection in patients with chronic hepatitis may increase the risk for severe hepatitis, and suggest that HBV as the newcomer may suppress the pre-existing HCV. Together with the earlier observation that acute HCV superinfection suppresses pre-existing HBV, it seems that the timing or sequence of infection is a factor influencing the outcome of viral interactions.

Assessment of intragastric pH value changes after early nasogastric feeding.

Studies have suggested that early feeding after injury decreases morbidity and mortality. Few reports, however, have focused on the change in pH inside the stomach after early tube feeding. The aim of the present study was the assessment of 1) the change in intragastric pH after surgery, and 2) the effect of early nasogastric tube feeding on intragastric pH value. From April 1997 to February 1998, 80 patients who underwent colon resection for colorectal cancer by a single surgeon entered the study and were randomized into four groups. Twenty patients (group I) were kept on NPO for 1 wk, and 20 patients per group (groups II, III, and IV) were fed through a nasogastric tube from the second to the seventh postoperative day with low-residual (Osmolite HN), high-fat (Pulmocare), and glutamine-containing (AlitraQ) enteral formulas. Feeding started at 500 kcal/500 cc/d. If the patient tolerated the formula well, feeding increased to 1500 kcal/1500 cc(-1)/d(-1) the following day. Intragastric pH was measured preoperatively and then twice daily until the sixth postoperative day. The pH value of intragastric juice increased significantly once feeding started (3. 67 +/- 1.33 on the third postoperative day; 4.28 +/- 1.26 on the six postoperative day). The pH value seemed only mildly affected by the patient's tolerance for tube feeding (poorly tolerated group, pH 3. 52 +/- 1.75 versus 3.75 +/- 1.21 in the well-tolerated group on the third postoperative day; poorly tolerated group, pH 3.67 +/- 1.02 versus 4.45 +/- 1.27 in the well-tolerated group on the sixth postoperative day). The pH value of intragastric juice was higher in group II than in groups III and IV (4.51 +/- 1.57, 3.90 +/- 1.20, 4. 42 +/- 0.89 respectively, on the sixth postoperative day). This series suggests that early nasogastric feeding can significantly elevate the intragastric pH value in patients after resection of colorectal cancer. Nasogastric feeding may decrease the incidence of stress ulceration by elevating the pH value of intragastric juice.

Genetic alternations of p73 are infrequent but may occur in early stage hepatocellular carcinoma.

p73, a structural homologue of the tumor suppressor gene, p53, has recently been identified and mapped to chromosome 1p36, where genomic loss of heterozygosity (LOH) often occurs in human hepatocellular carcinoma (HCC). To determine whether p73 is involved in the development of HCC and whether there is an inverse correlation between the mutations of p73 and p53, we examined 22 paired tumors/noncancerous liver tissues for allelic expression, LOH and mutation of p73 and for mutation of p53. p73 was biallelically expressed in noncancerous liver tissues and in 7 out of the 8 informative tumors. One tumor tissue expressed only a single allele. LOH of p73 was found in 2 out of the 11 (18%) informative cases. A tumor-specific five-nucleotide deletion mutation causing a reading frameshift/early truncation of p73 DNA-binding domain was found, in which case no concomitant mutation in the DNA-binding domain of p53 was identified. Nine out of the 22 cases (41%) contained tumor-specific mutations in the DNA-binding domain of p53. Two of the three cases with p73 genetic alternations had a tumor size of less than 2 centimeters. These results suggest that p73 is a biallelically expressed gene in the liver and that allelic loss and mutation of p73 is infrequent and may occur early in HCC. p73 is unlikely to be the putative tumor suppressor gene located at chromosome 1p36 in HCC.

Prednisolone priming enhances Th1 response and efficacy of subsequent lamivudine therapy in patients with chronic hepatitis B.

Asian lamivudine trial has shown that hepatitis B e antigen (HBeAg) seroconversion rate during 1 year of lamivudine therapy was only 16% but was 64% in the subgroup of patients with a pretherapy serum alanine transaminase (ALT) level over 5 times the upper limit of normal (ULN). To test whether ALT rebound following corticosteroid priming enhances response to lamivudine therapy, a pilot study was conducted in 30 patients with ALT levels less than 5x ULN (43-169; N < 36 U/L). They received 30 mg of prednisolone daily for 3 weeks, 15 mg daily for 1 week, no treatment for 2 weeks, and then 150 mg of lamivudine daily for 9 months. Complete response (CR) was defined as ALT normalization with HBV-DNA seroclearance and HBeAg seroconversion. Peripheral blood mononuclear cell proliferation and cytokine secretion in response to recombinant HBV core antigen were serially assayed in 7 patients during priming and after withdrawal of prednisolone. Clinical rebound with an ALT over 5x ULN was observed in 20 patients (67%). Of these 20, 12 (60%) showed CR as compared with 1 (10%) of the 10 patients without significant ALT rebound (P <.002). The HBeAg seroconversion sustained in 70% of the patients 3 to 6 months after the end of lamivudine therapy. Immunological assays revealed that the responders showed Th1 dominant response and higher stimulation index to prednisolone priming. No serious side effect was encountered. These results suggest that corticosteroid priming induced immune/ALT rebound greatly enhances response to lamivudine therapy in chronic hepatitis B. Confirmation by randomized controlled trial is needed.

Priority-setting for nursing research in the Republic of China.

The question of how public funds for research should be allocated has led to participatory priority-setting in prosperous democracies like Taiwan, Republic of China. Useful criteria for research priorities are scientific merit, social benefit and feasibility. Taking a health needs approach and using these criteria, nearly 200 nurses from service and education in a national forum participated in describing research priorities. Through the group method of idea-writing, for clinical nursing, of high priority were assessing quality, care of the elderly, and preventing infectious disease. For nursing education, research addressing advanced role preparation and bridging nursing education and practice were priorities. For nursing management, research of highest priority pertained to economic evaluation, personnel administration, and effectiveness. These suggestions from the deliberation of a committed group of nurses can help shape future national decisions about research funding and training.

Nurses' participation and utilization of research in the Republic of China.

A survey was done to improve understanding of nurses' participation in research activities and their utilization of research for practice in one developing country, the Republic of China. The sample for this 1996-1997 study was 382 staff nurses and nurse managers. Using two instruments designed for the project it was found that although research participation was low overall, 64% participated in some research activities with data collection and presentation at national conferences the most frequent activities. Nearly half the nurses had utilized research to change practice in the previous three years. The main barriers to utilization were lack of time and lack of staff. Role models, consultation and guidance to locate useful research were the main types of needed assistance. The findings provide direction for future training, education and managerial policy, especially for nurses in developing countries, which account for 84% of the world's population and 93% of the worldwide burden of disease.

Activation of nuclear factor kappaB in hepatitis C virus infection: implications for pathogenesis and hepatocarcinogenesis.

The hepatitis C virus (HCV) core protein is a multifunctional protein. It may bind to the death domain of tumor necrosis factor receptor 1 (TNFR1) and to the cytoplasmic tail of lymphotoxin-beta receptor, implying that it may be involved in the apoptosis and anti-apoptosis signaling pathways. In vitro studies have been inconclusive regarding its ability to inhibit or enhance TNF-alpha-induced apoptosis. To address this issue, electrophoretic mobility shift assay (EMSA) and immunohistochemical studies were used to show the activation of nuclear factor kappaB (NF-kappaB) in HCV-infected liver tissues and in HCV core-transfected cells. The activation of NF-kappaB was correlated with the apoptosis assays. The results showed that NF-kappaB activation could be shown in HCV-infected livers and HCV core-transfected cells. The data of EMSA correlated with those of immunohistochemical studies, which revealed a higher frequency of NF-kappaB nuclear staining in HCV-infected than in normal livers. NF-kappaB activation conferred resistance to TNF-alpha-induced apoptosis in HCV core-transfected cells. Inhibition of NF-kappaB activation by pyrrolidine dithiocarbamate sensitized them to TNF-alpha-induced apoptosis. These findings suggest that HCV infection may cause anti-apoptosis by activation of NF-kappaB and implicate a mechanism by which HCV may evade the host's immune surveillance leading to viral persistence and possibly to hepatocarcinogenesis.

Constitutive activation of nuclear factor kappaB in hepatocellular carcinoma.

BACKGROUND: Nuclear factor kappaB (NF-kappaB) is a transcription factor that plays important roles in cell proliferation and in immunity against viral infections. NF-kappaB is a dimer of Rel proteins that is sequestered in the cytoplasm as an inactive form through interaction with an inhibitory kappaB (IkappaB) protein. When IkappaB is degraded, the NF-kappaB dimer will enter the nucleus to activate the target genes. Chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection may activate NF-kappaB and, thus, may modulate cell apoptosis and may be associated with oncogenesis. The role of NF-kappaB in hepatocellular carcinoma (HCC) has not yet been explored. METHODS: Immunohistochemical staining to search for active nuclear RelA and nuclear IkappaBalpha proteins were done on formalin fixed liver tissues from 65 patients with HCC and from 9 normal control participants. Nuclear extracts of fresh-frozen tumor and nontumor liver tissues from 37 patients with HCC and from 7 normal controls were tested for NF-kappaB-DNA binding activity by electrophoretic mobility shift assay. The RelA and IkappaBalpha protein expressions were studied by Western blot analysis. RESULTS: Nuclear NF-kappaB stainings were significantly more abundant in HBV-infected or HCV-infected tumors as well as nontumor parts of HCC compared with normal controls. Nuclear NF-kappaB DNA binding activity and nuclear RelA protein expression were greater in tumor tissue compared with nontumor tissue, whereas cytosolic IkappaBalphs protein expression was generally greater in nontumor tissue compared with tumor tissue. CONCLUSIONS: Constitutive activation of NF-kappaB was found more frequently in tumor tissue compared with nontumor tissue. It is possible that NF-kappaB overexpression accompanied by dysregulation of IkappaBalpha may play a role in the hepatocarcinogenesis of HBV or HCV infection.

Ticlopidine-induced cholestatic hepatitis with anti-nuclear antibody in serum.

We describe a case of severe cholestatic hepatitis following administration of ticlopidine. A 57-year-old man without known liver disease developed jaundice approximately 3 weeks after initiation of ticlopidine for secondary prevention of stroke. Hyperbilirubinemia and abnormal liver function test values resolved 5 months after withdrawal of ticlopidine. The diagnosis of ticlopidine-induced cholestasis was made after thorough investigations had excluded other causes of jaundice. He was not retreated with ticlopidine. This case may serve to illustrate the possibility of ticlopidine hepatotoxicity, which has rarely been reported. Furthermore, to the best of our knowledge, ticlopidine-induced cholestatic hepatitis accompanied by autoantibody has not been previously reported. This case suggests that regular assessment of liver function should be performed in the initial 3 months of ticlopidine treatment due to the potential risk of adverse effects. In patients with abnormal biochemical test results, autoantibodies should be assessed.

Identifying attitudinal barriers to family management of cancer pain in palliative care in Taiwan.

The purpose of this study was threefold: (1) to examine attitudes held by Taiwanese family caregivers of hospice inpatients with cancer that serve as barriers to cancer pain management; (2) to determine the relationship of attitudinal barriers to family caregiver hesitancy to report pain and to administer analgesics; and (3) to determine the relationship of attitudinal barriers to the adequacy of analgesics used by the patient. A total of 80 pairs of palliative care inpatients and their primary family caregivers participated in this study. Family caregivers completed the Barriers Questionnaire-Taiwan (BQT) form and a demographic questionnaire. The instruments completed by patients consisted of the Brief Pain Inventory-Chinese version and a demographic questionnaire. The data revealed that Taiwanese family caregivers of palliative care patients with advanced cancer had concerns about reporting pain and administering analgesics, particularly as they related to disease progression, side-effects and p.r.n. analgesics. Older and less-educated family caregivers scored significantly higher on the BQT than did their younger, more educated counterparts. Family caregivers' concerns measured by the BQT were related to family caregivers' reluctance to administer analgesics to their patients. Implications for a broader understanding of analgesics in the advancement of pain management in palliative care in Taiwan are discussed.