[Correlation between fluid parameter and cardiovascular events in hemodialysis patients based on repeated body composition analyses].

Objective: To explore the correlation between fluid load index and cardiovascular events in hemodialysis patients based on repeated body composition analyses. Methods: A prospective cohort study was conducted to collect the clinical data of patients undergoing maintenance hemodialysis (MHD) in the Department of Nephrology, Hangzhou Hospital of Traditional Chinese Medicine from July to September 2020. The pre-dialysis fluid overload (FO) index-overhydration (OH) was measured by bioelectrical impedance method, and the follow-up monitoring was conducted every 6 months. According to the baseline OH value, patients were divided into non-FO group (OH≤2.5 L) and FO group (OH>2.5 L). Moreover, according to the repeated measurements, the patients were divided into continuous non-FO group, continuous FO group and intermittent FO group. All patients were followed up until October 1, 2022, and the outcomes were recorded. The end point of follow-up was cardiovascular events. The cumulative incidence of cardiovascular events was calculated by the Kaplan-Meier method, and the risk factors of cardiovascular events were analyzed by Cox proportional hazards regression model. Results: A total of 289 patients were included, including 88 patients (30.4%) with FO and 201 patients (69.6%) with non-FO. There were 168 males (58.1%) and 121 (41.9%) females, with an average age of (58±13) years and an average follow-up time of (22.0±6.5) months. Kaplan-Meier analysis showed that the incidence of cardiovascular events in the baseline FO group was higher than that in the non-FO group (log-rank χ2=14.44, P<0.001). The incidence of cardiovascular events in both the continuous FO group and the intermittent FO group was higher than that in the continuous non-FO group (log-rank χ2=41.47, P<0.001; log-rank χ2=18.36, P<0.001). After adjustment for gender, age, comorbidities, and biochemical indicators, the incidence of cardiovascular events in the baseline FO group was 1.850 times of the non-FO group (95%CI: 1.046-3.271, P=0.034). The incidence of cardiovascular events in the continuous FO group was 4.679 times of the continuous non-FO group (95%CI: 2.189-10.002, P<0.001). The incidence of cardiovascular events in the intermittent FO group was 3.410 times of the continuous non-FO group (95%CI: 1.696-6.857, P=0.001). Conclusions: OH value measured by bioelectrical impedance can be used as an important reference index for clinical monitoring of cardiovascular events in MHD patients. Continuous chronic and intermittent exposures to FO are risk factors for cardiovascular events in hemodialysis patients.

One-year outcomes of an osteoporosis liaison services program initiated within a healthcare system.

Due to the huge gap in the care of patients with osteoporosis and fragility fractures, we aimed to explore the effectiveness of the osteoporosis liaison service (OLS) in osteoporosis care. We found that OLS can improve osteoporosis care, including increasing medication compliance, increasing calcium/vitamin D/protein intake, and reducing fall rate. INTRODUCTION: A significant gap exists in the care of patients with osteoporosis and fragility fractures. This study aimed to evaluate 1-year outcomes of an osteoporosis liaison service (OLS) program that includes two independent components: medication management services (MMS) to improve medication adherence and fracture liaison services (FLS) for secondary prevention. METHODS: Patients with new hip fracture or untreated vertebral fractures enrolled in the FLS program (n = 600), and those with osteoporosis medication management issues but not necessarily fragility fractures enrolled in the MMS program (n = 499) were included. To evaluate outcomes, care coordinators assessed baseline items adapted from the 13 Best Practices Framework (BPF) standards of the International Osteoporosis Foundation, with telephone follow-up every 4 months for 1 year. RESULTS: Mean age of this cohort was 76.2 ± 10.3 years, 78.8% were female. After 1-year participation in the program, all patients had received bone mineral density tests, and medication adherence for the entire cohort at 12 months was 91.9 ± 19.6%, with significant improvement in fall rates (23.4% reduction), exercise rates (16.8% increase), calcium intake (26.5% increase), vitamin D intake (26.4% increase), and adequate protein intake (17.3% increase) (all p < 0.05). After 1-year OLS program, the overall rates of mortality, incident fracture, and falls were 6.6%, 4.0%, and 24.3%, respectively. CONCLUSIONS: The OLS program is associated with improved osteoporosis care, including increased medication adherence, calcium/vitamin D and protein intake, and reduced fall rate.

miR-34a and miR-125a-5p inhibit proliferation and metastasis but induce apoptosis in hepatocellular carcinoma cells via repressing the MACC1-mediated PI3K/AKT/mTOR pathway.

microRNA-34a (miR-34a) and microRNA-1251-5p (miR-125a-5p) were considered as tumor suppressors in hepatocellular carcinoma (HCC). Nevertheless, the modulatory mechanisms of miR-34a and miR-125a-5p in HCC haven't been completely understood. The levels of metastasis-associated with colon cancer 1 (MACC1) and miRNAs (miR-34a and miR-125a-5p) were determined by quantitative real-time polymerase chain reaction (qRT-PCR), and the levels of associated proteins were detected by western blot assay. Cell proliferation and metastasis were examined via Cell Counting Kit-8 (CCK-8) and transwell assays, respectively. Cell apoptosis was measured through flow cytometry. The effect of MACC1 on HCC in vivo was explored via xenograft assay. Dual-luciferase reporter assay and RNA Immunoprecipitation (RIP) assay were implemented to explore the target correlation. The expression of MACC1 was upregulated in HCC tissues and cells. Knockdown of MACC1 inhibited proliferation and metastasis but expedited apoptosis of HCC cells and the repression of tumor growth in vivo was evoked by MACC1 downregulation. Both miR-34a and miR-125a-5p directly targeted MACC1 and repressed the expression of MACC1 in HCC cells. Overexpression of miR-34a or miR-125a-5p restrained cell proliferation and metastasis while induced apoptosis by downregulating MACC1 in HCC cells. miR-34a and miR-125a-5p repressed phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signal pathway via reducing MACC1 in HCC cells. miR-34a and miR-125a-5p refrained proliferation and metastasis while motivated apoptosis in HCC cells through the PI3K/AKT/mTOR pathway by repressing MACC1. miR-34a and miR-125a-5p might be splendid biomarkers in the therapeutic strategies for HCC.

Body mass index and depressive symptoms in adolescents in Taiwan: testing mediation effects of peer victimization and sleep problems.

BACKGROUND: Despite recognition of the link between body mass index (BMI) and depression in adolescence, the underlying mechanisms behind this association remain understudied. This study aims to examine three mediational pathways from BMI to depressive symptoms through peer victimization and sleep problems. Sex differences in the mediating effects were also explored. METHODS: Data came from 1893 adolescents participating in a multi-wave longitudinal study from grade 9 to 12 in northern Taiwan were analyzed. Measures included BMI in 2009, peer victimization in 2010, sleep problems in 2011, depressive symptoms in 2012 and other covariates (sex, age, parental education, family structure, family economic stress, stressful life events, pubertal development and previous scores of focal study variables). A series of multiple regression models were conducted to test mediation hypotheses. A bootstrapping approach was applied to obtain confidence intervals for determining the significance of indirect effects. RESULTS: The association between BMI and depressive symptoms was significantly mediated by peer victimization and sleep problems. Higher BMI predicted more peer victimization and sleep problems, each of which led to higher levels of depressive symptoms. Our results further showed that higher BMI was associated with more peer victimization, which led to greater sleep problems and in turn resulted in increased depressive symptoms. No sex differences was found for the indirect effects of BMI on depressive symptoms through either peer victimization or sleep problems. CONCLUSIONS: Peer victimization and sleep problems partly explain the link between BMI and depressive symptoms. Interventions to prevent or manage depressive symptoms may yield better results if they consider the effects of these two psychosocial factors rather than targeting BMI alone.

Hepatitis C viraemia reversibly maintains subset of antigen-specific T-bet+ tissue-like memory B cells.

BACKGROUND: Chronic antigen exposure and/or ageing increases the frequency of T-box expressed in T cells (T-bet)-expressing B-lymphocytes in mice. The frequency and significance of B-cell T-bet expression during chronic hepatitis C (HCV) infection in human subjects has never been described. METHODS: Healthy controls, cirrhotic and noncirrhotic HCV-infected patients, and non-HCV patients with cirrhosis were recruited. Peripheral blood mononuclear cells were phenotyped for expression of T-bet and related markers by flow cytometry. In a subset of patients who underwent antiviral therapy and were cured of HCV infection (sustained virological response), the dynamics of T-bet expression in B cells was monitored. After cure, convalescent B cells were tested for T-bet expression after re-exposure to infected plasma or recombinant HCV proteins. RESULTS: Forty-nine patients including 11 healthy donors, 30 hepatitis C-infected individuals (nine with liver cancer, 13 with cirrhosis, eight without cirrhosis) and eight patients with cirrhosis due to non-HCV-related cause were recruited. We found that B cells in patients with chronic HCV exhibited increased frequency of T-bet+ B cells relative to noninfected individuals (median 11.5% v. 2.2%, P<.0001) but that there were no significant differences between noncirrhotic, cirrhotic and cancer-bearing infected individuals. T-Bet+ B cells expressed higher levels of CD95, CXCR3, CD11c, CD267 and FcRL5 compared to T-bet- B cells and predominantly exhibit a tissue-like memory CD27- CD21- phenotype independent of HCV infection. T-bet+ B cells in HCV-infected patients were more frequently class-switched IgD- IgG+ (40.4% vs. 26.4%, P=.012). Resolution of HCV infection with direct-acting antiviral (DAA) therapy leads to a marked reduction in the frequency of T-bet+ B cells (median 14.1% pretreatment v. 6.7% end of treatment v. 6.1% SVR12, P≤.01). Re-exposure of convalescent (cured) B cells to viremic plasma and recombinant HCV E2 protein led to re-expression of T-bet. CONCLUSION: Chronic antigenemia in chronic HCV infection induces and maintains an antigen-specific T-bet+ B cell. These B cells share markers with tissue-like memory B cells. Antigen-driven T-bet expression may be a critical suppressor of B-cell activation in chronic HCV infection.

Eco-friendly luminescent solar concentrators with low reabsorption losses and resistance to concentration quenching based on aqueous-solution-processed thiolate-gold nanoclusters.

Heavy-metal-containing quantum dots (QDs) with engineered electronic states have been served as luminophores in luminescent solar concentrators (LSCs) with impressive optical efficiency. Unfortunately, those QDs involve toxic elements and need to be synthesized in a hazardous solvent. Recently, biocompatible, eco-friendly gold nanoclusters (AuNCs), which can be directly synthesized in an aqueous solution, have gained much attention for promising applications in 'green photonics'. Here, we explored the solid-state photophysical properties of aqueous-solution-processed, glutathione-stabilized gold nanoclusters (GSH-AuNCs) with a ligand-to-metal charge-transfer (LMCT) state for developing 'green' LSCs. We found that such GSH-AuNCs exhibit a large Stokes shift with almost no spectral overlap between the optical absorption and PL emission due to the LMCT states, thus, suppressing reabsorption losses. Compared with GSH-AuNCs in solution, the photoluminescence quantum yields (PL-QYs) of the LSCs can be enhanced, accompanied with a lengthened PL lifetime owing to the suppression of non-radiative recombination rates. In addition, the LSCs do not suffer from severe concentration-induced PL quenching, which is a common weakness for conventional luminophores. As a result, a common trade-off between light-harvesting efficiency and solid-state PL-QYs can be bypassed due to nearly-zero spectral overlap integral between the optical absorption and PL emission. We expect that GSH-AuNCs hold great promise for serving as luminophores for 'green' LSCs by further enhancing solid-state PL-QYs.

[CT findings of inflammatory myofibroblastic tumor of different pathological types].

Objective: To explore the computed tomography(CT) features of inflammatory myofibroblastic tumor(IMT) in different pathological types, and improve the diagnostic level of this disease. Methods: The CT features of 29 cases pathologically confirmed IMTs were retrospectively reviewed along with a literature review to analyze the CT features and pathological correlations, and three kinds of pathological classification of IMT in patients with gender , shape, boundary and location were respectively analyzed by Chi-Square test. Results: The age ranges from 2 to 78 years.There were 7 cases of mucinous blood vessel type and 13 cases of spindle cell type and 9 cases of fiber type.Immunohistochemically, Vimentin (22/29) and SMA (28/29) were positive in all the cases, ALK (4/29) and CD-67(6/29) were partly positive expression, other markers such as S-100 were negative expression.The Chi-Square test showed that there were statistically differences in the gender of the patients. Conclusion: The CT and clinical features differ according to pathological types of IMT. Its final diagnosis still needs to be combined with pathology and immunohistochemistry result. In all, CT has a role in assessing the extension of IMT and especially about the relationship with adjacent organs which can effectively direct the establishment of clinical treating scheme.

[Combined use of wide-detector and adaptive statistical iterative reconstruction-V technique in abdominal CT with low radiation dose].

Objective: To investigate the image quality and radiation dose with wide-detector(80 mm) and adaptive statistical iterative reconstruction-V (ASIR-V) technique at abdominal contrast enhanced CT scan. Methods: In the first phantom experiment part, the percentage of ASIR-V for half dose of combined wide detector with ASIR-V technique as compared with standard-detector (40 mm) technique was determined. The human experiment was performed based on the phantom study, 160 patients underwent contrast-enhanced abdominal CT scan were prospectively collected and divided into the control group (n=40) with image reconstruction using 40% ASIR (group A) and the study group (n=120) with random number table. According to pre-ASIR-V percentage, the study group was assigned into three groups[40 cases in each group, group B: 0 pre-ASIR-V scan with image reconstruction of 0-100% post-ASIR-V (interval 10%, subgroups B0-B10); group C: 20% pre-ASIR-V with 20%, 40% and 60% post-ASIR-V (subgroups C1-C3); group D: 40%pre-ASIR-V with 40% and 60% post-ASIR-V (subgroups D1-D2)]. Image noise, CT attenuation values and CNR of the liver, pancreas, aorta and portal vein were compared by using two sample t test and One-way ANOVA. Qualitative visual parameters (overall image quality as graded on a 5-point scale) was compared by Mann-Whitney U test and Kruskal-Wallis H test. Results: The phantom experiment showed that the percentage of pre-ASIR-V for half dose was 40%. With the 40% pre-ASIR-V, radiation dose in the study group was reduced by 35.5% as compared with the control group. Image noise in the subgroups of B2-B10, C2-C3 and D1-D2 were lower (t=-14.681--3.046, all P<0.05) while CNR in the subgroups of B4-B10, C2-3 and D1-D2 were higher(t=2.048-9.248, all P<0.05)than those in group A, except the CNR of liver in the arterial phase (AP) in C2, D1 and D2 and the CNR of pancreas in AP in D1 (t=0.574-1.327, all P>0.05). The subjective image quality scores increased gradually in the range of 0-60% post-ASIR-V and decreased with post-ASIR-V larger than 70%. The overall image quality of subgroup B3-B8, C2-C3 and D1-D2 were higher than that in group A (Z=-2.229--6.533, all P<0.05). Conclusion: Compared with stand-detector together with ASIR technique, wide-detector combined with 40% pre-ASIR-V technique with 60% post-ASIR-V image reconstruction can reduce radiation dose while maintain good overall image quality.

Experimental infection of tick cells with Nipah virus.

Nipah virus (NiV), a highly pathogenic henipavirus of the family Paramyxoviridae, which causes fatal encephalitis in 40-70% of affected patients, was first reported in Malaysia over 20 years ago. Pteropid bats are the natural hosts of henipaviruses, and ticks have been proposed as a possible link between bats and mammalian hosts. To investigate this hypothesis, infection of the tick cell line IDE8 with NiV was examined. Presence of viral RNA and antigen in the NiV-infected tick cells was confirmed. Infectious virions were recovered from NiV-infected tick cells and ultrastructural features of NiV were observed by electron microscopy. These results suggest that ticks could support NiV infection, potentially playing a role in transmission.

A conventional multiplex PCR for the detection of four common soil-transmitted nematodes in human feces: development and validation.

Soil-transmitted helminth (STH) infections, mainly caused by Ascaris lumbricoides, Trichuris trichiura, and hookworms, are among the most common intestinal parasites that infect humans. The infections are widely distributed throughout tropical and subtropical countries, including Malaysia, particularly in underprivileged communities. Microscopic and culture techniques have been used as a gold standard for diagnostic techniques. However, these methods yield low sensitivity and specificity, laborious and time-consuming. Therefore, simple, rapid, and accurate alternative methods are needed for the simultaneous detection of STH infections. Although advanced technologies such as real-time multiplex PCR have been established, the use of this technique as a routine diagnostic is limited due to the high cost of the instrument. Therefore, a single-round multiplex conventional PCR assay for rapid detection of four STH species in the fecal sample was developed in this study. To perform the single-round multiplex PCR, each pair of species-specific primers was selected from target genes, including Ancylostoma duodenale (Internal Transcribed Spacer 2; accession No. AJ001594; 156 base pair), Necator americanus (ITS 2; accession No. AJ001599; 225 base pair), Ascaris lumbricoides (Internal Transcribed Spacer 1; accession No. AJ000895; 334 base pair) and Trichuris triciura (partial ITS 1, 5.8s rRNA and partial ITS 2; accession No. AM992981; 518 base pair). The results showed that the newly designed primers could detect the DNA of STH at low concentrations (0.001 ng/ µl) with no cross-amplification with other species. This assay enables the differentiation of single infections as well as mixed infections. It could be used as an alternative and is a convenient method for the detection of STHs, especially for the differentiation of N. americanus and A. duodenale.

Association between coronary artery calcification using low-dose MDCT coronary angiography and bone mineral density in middle-aged men and women.

UNLABELLED: Six hundred sixty-one participants who had at least one cardiac risk factor but were without known coronary heart disease underwent low-dose multidetector computed tomography coronary angiography (MDCT-CA) and dual-energy X-ray absorptiometry. The association between presence of subclinical coronary calcified plaque and low bone mineral density for the middle-aged individual was not significant after multivariate adjustment. INTRODUCTION: Results of previous clinical studies assessing the relationship between osteoporosis and coronary calcification are inconsistent. This study aimed to evaluate the association between subclinical coronary calcification and osteoporosis in middle-aged men, premenopausal women, and postmenopausal women by using low-dose MDCT-CA and bone mineral density (BMD). METHODS: This study enrolled 661 participants with at least one cardiac risk factor but without known coronary artery disease (CAD). All subjects underwent low-dose MDCT-CA and dual-energy X-ray absorptiometry on the same day. RESULTS: The mean age was 52.2 years for men, 44.8 years for premenopausal women, and 59.1 years for postmenopausal women. The prevalence of calcified plaques between men with normal BMD and low BMD at lumbar spine were significantly different (P=0.042). The prevalence of mixed plaque and calcified plaque between pre- and postmenopausal women with normal BMD and low BMD at lumbar spine and femoral neck were not significantly different (P>0.05). Possible association between lumbar spine, femoral neck, and total proximal femur BMD and the presence of CAP was evaluated for men, premenopausal women, and postmenopausal women using multivariate logistic regression analysis: results were not significant (P>0.05). CONCLUSION: Our study demonstrates that the association between the presence of subclinical coronary calcification and low BMD among middle-aged men and women was not significant after controlling for age and other risk factors for CAD and osteoporosis.

Association of metabolic syndrome and diabetes with subclinical coronary stenosis and plaque subtypes in middle-aged individuals.

AIMS: The presence of subclinical stenosed coronary segments and plaque subtypes has not been compared among those with metabolic syndrome, diabetes, or neither condition in middle-aged individuals. In select, intermediate-risk subjects, it may be reasonable to directly measure atherosclerosis burden by low-dose, multidetector-row computed tomographic coronary angiography. METHODS: We performed a cross-sectional analysis of 1024 consecutive, newly self-referred subjects (692 men, 332 women; mean age 53.0±9.7 years) who underwent health evaluation at the China Medical University Hospital. Participants had at least one cardiac risk factor, but no known coronary heart disease. RESULTS: Among our 1024 subjects, 135 had diabetes, 334 had metabolic syndrome and 555 had neither condition. The subjects with diabetes and those with metabolic syndrome had a higher prevalence of non-calcified, calcified and mixed-type plaques and stenosed coronary segments than the subjects with neither condition (P<0.05). The odds ratios for diabetes and the presence of any plaque, mixed plaque, calcified plaque and stenosed segment compared with neither metabolic syndrome nor diabetes were 2.893, 3.629, 2.099 and 2.036, respectively, all of which were significant (P<0.05). The odds ratio for metabolic syndrome and the presence of any plaque compared with neither metabolic syndrome nor diabetes was 1.606 (95% CI 1.063-2.426; P<0.05). CONCLUSION: In middle-aged subjects, diabetes was related to an increased risk of the presence of mixed plaques, calcified plaques and stenosed coronary segments. However, metabolic syndrome was related to an increased risk of the presence of any coronary plaque, but not related to stenosed coronary segments.

A program to interest medical students in Changhua, Taiwan in the incorporation of visual arts in medicine.

INTRODUCTION: Visual arts have been used to facilitate the teaching of the United States Accreditation Council for Graduate Medical Education (ACGME) competencies used in some countries. Some medical students may not appreciate the usefulness of incorporating arts in medical education. Therefore, arts programs that can interest medical students are necessary. We initiated and evaluated a visual arts program at the Changhua Christian Hospital in Changhua, Taiwan, with an aim to give the students a short review of visual arts and to interest them in the incorporation of arts in medicine. METHODS: A total of 110 students in clerkship or internship participated in a visual arts program with emphasis on medicine-related visual arts. Content analysis of the data from the notes made by the instructor from direct observation of students; descriptions during discussions and the written feedback from students at the end of the program was used to evaluate the effect of the program. Anonymous questionnaires were also used for self-assessment of students. RESULTS: Qualitative analysis of the data revealed that the course was interesting to students. Themes emerged including its helpfulness to students in interpreting paintings, enhanced empathy, increased cultural awareness, enhanced observational skills, better team work, listening and communication skills and reduced stress. Ratings on the questionnaire showed similar results. Moreover, students had an increase in their confidence and desire to interpret paintings. CONCLUSION: The structured visual arts program, with emphasis on medicine-related visual arts and other humanities subjects, was able to attract the attention of medical students. It might be helpful to improve the required skills of ACGME competencies, but further studies are needed to support these conclusions.

Effects of areca nut extract on the apoptosis pathways in human neutrophils.

BACKGROUND AND OBJECTIVE: Areca nut, a major component in area quid, possesses genotoxic and carcinogenic activities. Areca nut extract (ANE) may affect the defensive functions of neutrophils. Recent studies suggest that areca nut chewing is associated with a higher prevalence of periodontal disease as a result of the detrimental effects of ANE on the host defense system. This study examined the effects of ANE on the apoptosis pathways in human neutrophils. MATERIAL AND METHODS: Apoptosis/necrosis of neutrophils was determined using flow cytometry. Proteins involved in the apoptosis pathway were determined using western blotting analysis. RESULTS: The results indicated that ANE reduced early apoptosis, but increased the primary necrosis of neutrophils. ANE may arrest neutrophils in the G0/G1 phase and reduce the apoptotic hypodiploid DNA contents. The levels of cleaved forms of poly(ADP-ribose) polymerase, and of caspase-3 and caspase-8 were decreased by treatment with ANE. Moreover, glycogen synthase kinase-3 alpha/beta may be involved in the ANE-modulated effects of neutrophils. CONCLUSION: Areca nut may regulate death pathways in neutrophils. This may be one mechanism by which areca nut compromises the periodontal health of areca nut chewers.

Toxoplasma gondii infection among selected indigenous community in Sarawak, East Malaysia.

Toxoplasma gondii is an obligate intracellular protozoan parasite that causes toxoplasmosis in humans. To date, little is known about T. gondii infection among the indigenous community, particularly in East Malaysia. This study was conducted to determine the status of T. gondii infection and to investigate associated risk factors among the indigenous community of Sarawak, East Malaysia. The sociodemographic data was obtained using a pretested questionnaire. A serological test was done to detect the presence of specific IgM and IgG antibodies against T. gondii in serum samples. A nested polymerase chain reaction (PCR) was used to determine acute infection among seropositive individuals. The overall seroprevalence of T. gondii infection was 50% (95% CI = 43.3 - 56.7). From this subset, 40.1%, 5.7%, and 4.2% were positive for anti-T. Gondii IgG antibodies, IgM, and both IgG and IgM, respectively. Four seropositive samples were amplified through PCR. None of the pregnant women tested positive for T. gondii infection based on the serological and PCR assays. A significant association was found between age, low monthly household income, unemployment, usage of untreated water and close contact with T. gondii seropositive cats. These results provide basic information on T. gondii infection and may be useful for policymakers to initiate prevention and control programs, especially amongst pregnant women and women of childbearing age in the indigenous community.

Molecular immunocytochemistry of the CuZn superoxide dismutase in rat hepatocytes.

The distribution of CuZn superoxide dismutase (SOD) molecules in subcellular organelles in rat liver hepatocytes was studied using integrated biochemical, stereological, and quantitative immunocytochemical techniques. A known concentration of purified CuZn SOD in 10% gelatin was embedded alongside the liver tissue for the calculation of CuZn SOD concentrations in hepatocyte organelles and total CuZn SOD in the rat liver. Most of the CuZn SOD was located in the cytoplasmic matrix (73.1%) and in the nucleus (11.9%) with concentrations of 1.36 and 0.71 mg/cm3, respectively. Lysosomes contained the highest concentration (5.81 mg/cm3). Only low concentrations were measured in mitochondria (0.21 mg/cm3). Membrane-bound spaces of rough endoplasmic reticulum (ER), smooth ER, and the Golgi system did not contain significant concentrations of the enzyme. By adding up the concentrations in all subcellular compartments, a total liver content of CuZn SOD was established from the immunocytochemical measurements (0.386 +/- 0.028 mg/gm liver) that agreed closely with those obtained by biochemical assays (0.380 +/- 0.058 mg/gm liver). The average distances between two CuZn SOD molecules can be calculated from enzyme concentrations. It was determined that CuZn SOD molecules in the cytoplasmic matrix and nucleus were 34 and 42 nm apart, respectively. In peroxisomes and mitochondria, average intermolecular distance increased to approximately 60 nm and increased to 136 nm in smooth ER. CuZn SOD is a relatively abundant protein in the cytosol of hepatocytes and its distribution overlaps with major sites of O2- production. The efficiency of protection CuZn SOD can provide to cytosolic proteins from attacks by superoxide anion depends on the rate of O2- production, distribution of CuZn SOD relative to cytosolic proteins, and the relative reaction rates between O2- with both cytosolic proteins and CuZn SOD. Future studies of these substrate-enzyme relationships in vivo can lead to a greater understanding of how cells handle oxidant stress.

Heparin induces dimerization and confers proliferative activity onto the hepatocyte growth factor antagonists NK1 and NK2.

Hepatocyte growth factor (HGF) is a potent epithelial mitogen whose actions are mediated through its receptor, the proto-oncogene c-Met. Two truncated variants of HGF known as NK1 and NK2 have been reported to be competitive inhibitors of HGF binding to c-Met, and to function as HGF antagonists (Lokker, N.A., and P.J. Godowski. 1993. J. Biol. Chem. 268: 17145-17150; Chan, A.M., J.S. Rubin, D.P. Bottaro, D.W. Hirschfield, M. Chedid, and S.A. Aaronson. 1991. Science (Wash. DC). 254:1382-1387). We show here, however, that NK1 acts as a partial agonist in mink lung cells. Interestingly, NK1, which is an HGF antagonist in hepatocytes in normal conditions, was converted to a partial agonist by adding heparin to the culture medium. The interaction of NK1 and heparin was further studied in BaF3 cells, which express little or no cell surface heparan sulfate proteoglycans. In BaF3 cells transfected with a plasmid encoding human c-Met, heparin and NK1 synergized to stimulate DNA synthesis and cell proliferation. There was no effect of heparin on the IL-3 sensitivity of BaF3-hMet cells, and no effect of NK1 plus heparin in control BaF3 cells, indicating that the response was specific and mediated through c-Met. The naturally occurring HGF splice variant NK2 also stimulated DNA synthesis in mink lung cells and exerted a heparin-dependent effect on BaF3-hMet cells, but not on BaF3-neo cells. The activating effect of heparin was mimicked by a variety of sulfated glycosaminoglycans. Mechanistic studies revealed that heparin increased the binding of NK1 to BaF3-hMet cells, stabilized NK1, and induced dimerization of NK1. Based on these studies, we propose that the normal agonist activity of NK1 and NK2 in mink lung cells is due to an activating interaction with an endogenous glycosaminoglycan. Consistent with that model, a large portion of the NK1 binding to mink lung cells could be blocked by heparin. Moreover, a preparation of glycosaminoglycans from the surface of mink lung cells induced dimerization of NK1. These data show that the activity of NK1 and NK2 can be modulated by heparin and other related glycosaminoglycans to induce proliferation in cells expressing c-Met.

Areca nut extracts increased expression of inflammatory cytokines, tumor necrosis factor-alpha, interleukin-1beta, interleukin-6 and interleukin-8, in peripheral blood mononuclear cells.

BACKGROUND AND OBJECTIVE: Cytokines represent a central role in inflammatory tissue destruction and regulate the immune responses that may govern the progression of periodontal diseases. This study investigated the effects of areca nut extracts on the expression of inflammatory cytokines, tumor necrosis factor-alpha, interleukin-1beta, interleukin-6 and interleukin-8 in peripheral blood mononuclear cells. The role of oxidative stress of areca nut extracts was also examined using curcumin. MATERIAL AND METHODS: The expression of cytokines in peripheral blood mononuclear cells treated with extracts of ripe areca nut or extracts of tender areca nut was analyzed using enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction. RESULTS: Both extracts of ripe areca nut (< or = 40 microg/mL) and extracts of tender areca nut significantly enhanced the production of tumor necrosis factor-alpha and interleukin-1beta in peripheral blood mononuclear cells in a dose-dependent and time-dependent manner. The kinetics of mRNA expression of both cytokines was also enhanced by areca nut extracts. The stimulatory effects of areca nut extracts on the secretion of tumor necrosis factor-alpha, interleukin-1beta, interleukin-6 and interleukin-8 and on the mRNA expression of tumor necrosis factor-alpha, interleukin-1beta and interleukin-6 at 4 h of incubation were reduced by curcumin (20-50 microm). However, the level of interleukin-8 transcripts was not affected by curcumin. Moreover, interleukin-1beta induction by extracts of tender areca nut, but not by extracts of ripe areca nut, was weakened by 10 microm curcumin. The inhibitory effects of curcumin may vary with different cytokines and with different areca nut extract treatments. CONCLUSION: The complex cytokine profile induced by areca nut extracts-treated peripheral blood mononuclear cells implied the possibility of enhanced local inflammation and altered immune functions by the areca chewing habit. The inhibitory effects of curcumin on cytokine expression suggested that oxidative stress might be involved in areca nut extracts-associated immune alteration.

Effect of amorphous layers on the interpretation of restored exit waves.

The effects of amorphous layers on the quality of exit wave restorations have been investigated. Two independently developed software implementations for exit wave restoration have been used to simulated focal series of images of <001> SrTiO3 with amorphous carbon layers incorporated. The restored exit waves have been compared both qualitatively and quantitatively. We have shown that amorphous layers have a strong impact on the quantitative measurements of atomic column positions, however, the error in the position measurements is still in the picometer range.