Oleanolic acid derivative alleviates cardiac fibrosis through inhibiting PTP1B activity and regulating AMPK/TGF-β/Smads pathway

Cardiac fibrosis (CF) in response to persistent exogenous stimuli or myocardial injury results in cardiovascular diseases (CVDs). Protein tyrosine phosphatase 1B (PTP1B) can promote collagen deposition through regulating AMPK/TGF-β/Smads signaling pathway, and PTP1B knockout improves cardiac dysfunction against overload-induced heart failure. Oleanolic acid (OA) has been proven to be an inhibitor of PTP1B, and its anti-cardiac remodeling effects have been validated in different mouse models. To improve the bioactivity of OA and to clarify whether OA derivatives with stronger inhibition of PTP1B activity have greater prevention of cardiac remodeling than OA, four new OA derivatives were synthesized and among them, we found that compound B had better effects than OA in inhibiting cardiac fibrosis both in vivo in the isoproterenol (ISO)-induced mouse cardiac fibrosis and in vitro in the TGF-β/ISO-induced 3T3 cells. Combining with the results of molecular docking, surface plasmon resonance and PTP1B activity assay, we reported that OA and compound B directly bound to PTP1B and inhibited its activity, and that compound B showed comparable binding capability but stronger inhibitory effect on PTP1B activity than OA. Moreover, compound B presented much greater effects on AMPK activation and TGF-β/Smads inhibition than OA. Taken together, OA derivative compound B more significantly alleviated cardiac fibrosis than OA through much greater inhibition of PTP1B activity and thus much stronger regulation of AMPK/TGF-β/Smads signaling pathway.

[Investigation of serum surface active protein D and clara cell protein levels in workers exposed to silica dust in ferrous metal foundry]

Objective: To investigate the levels of serum surface active protein D (SP-D) and clara cell protein (CCl6) in workers exposed to black silica dust, and analyze its influencing factors. Methods: From July to September 2021, 174 workers in 37 positions exposed to silica dust in 5 ferrous metal foundry were investigated by cross-sectional research method. The exposure concentration of silica dust workers was obtained through occupational health field investigation and detection, and the general situation of the study subjects was obtained through questionnaire survey and peripheral blood was collected. Double antigen sandwich enzyme-linked immunosorbent assay (ELISA) was used to detect the concentrations of SP-D and CC16 in serum of workers. The mean values were compared by one-way ANOVA, and the influencing factors of SP-D and CC16 concentrations in serum were analyzed by ordered multiple logistic regression. Results: The time-weighted average concentration (C-TWA) of 174 workers exposed to silica dust (respirable dust) ranged from 0.09 mg/m(3)~3.58 mg/m(3), and the C-TWA overstandard rate of dust exposed workers was 32.18% (56/174) , with differences among workers in different positions (χ(2)=28.85, P<0.001) . The highest concentration of silica dust was (0.82±0.11) mg/m(3). Using C-TWA<50% OEL occupational exposure limit (OEL) as reference, serum SP-D concentration in workers with ≥50% OEL was increased (OR=4.95, 95%CI: 1.86~13.17, P=0.001) , while CC16 concentration was decreased (OR=0.15, 95%CI: 0.05~0.40, P<0.001) ; Serum CC16 concentration decreased in workers exposed to silica dust C-TWA≥OEL (OR=0.46, 95%CI: 0.28~0.98, P=0.043) . Compared with those with low occupational health literacy, the serum SP-D concentration of workers with high occupational health literacy decreased (OR=0.48, 95%CI: 0.25~0.92, P=0.027) and CC16 concentration increased (OR=2.09, 95%CI: 1.10-3.97, P=0.024) . Conclusion: When no abnormality was found in the physical examination of workers, the serum SP-D and CC16 concentration levels changed, and the change was related to the concentration of workers exposed to silica dust.

The PIWI-specific insertion module helps load longer piRNAs for translational activation essential for male fertility

PIWI-clade proteins harness piRNAs of 24-33 nt in length. Of great puzzles are how PIWI-clade proteins incorporate piRNAs of different sizes and whether the size matters to PIWI/piRNA function. Here we report that a PIWI-Ins module unique in PIWI-clade proteins helps define the length of piRNAs. Deletion of PIWI-Ins in Miwi shifts MIWI to load with shorter piRNAs and causes spermiogenic failure in mice, demonstrating the functional importance of this regulatory module. Mechanistically, we show that longer piRNAs provide additional complementarity to target mRNAs, thereby enhancing the assembly of the MIWI/eIF3f/HuR super-complex for translational activation. Importantly, we identify a c.1108C>T (p.R370W) mutation of HIWI (human PIWIL1) in infertile men and demonstrate in Miwi knock-in mice that this genetic mutation impairs male fertility by altering the property of PIWI-Ins in selecting longer piRNAs. These findings reveal a critical role of PIWI-Ins-ensured longer piRNAs in fine-tuning MIWI/piRNA targeting capacity, proven essential for spermatid development and male fertility.

[Epidemiological characteristics of a local cluster epidemic caused by 2019-nCoV Delta variant in Ningbo, 2021]

Objective: To understand the epidemiological characteristics of a local clustered epidemic caused by 2019-nCoV Delta variant in Ningbo and provide reference for the improvement of COVID-19 epidemic prevention and control. Methods: Case finding was conducted based on case definitions, and field epidemiological investigation of COVID-19 cases was carried out. In which Nasal and oropharyngeal swabs of the cases were collected for pathogen testing, and the results were analyzed with descriptive epidemiological methods. Results: A total of 74 COVID-19 cases were reported in this epidemic, and the cases were mainly mild ones, accounting for 87.84% (65/74), and there were no severe or critical cases. The epidemic curve showed a human-to-human transmission mode, indicating that a transmission for at least six generations had occurred. The age of the COVID-19 patients ranged from 2 years to 80 years, and 27.03% (20/74) of the cases were older than 60 years. The cases were mainly workers (55.41%, 41/74) and housework/the unemployed (27.03%, 20/74). The COVID-19 epidemic was limited, and no further spread to other areas occurred. The transmission chain among the cases was clear, and the gene sequencing results confirmed that the current epidemic was caused by 2019-nCoV Delta variant, which was highly homologous to the strains from other province. Conclusion: The local COVID-19 epidemic in Ningbo was caused by imported cases of COVID-19 from other province, and local community spread occurred through daily contacts between cases and contacts.

[Analysis of dust hazard characteristics in 59 ferrous metal foundry enterprises in Ningbo City]

Objective: To analyze the post distribution of dust concentration in ferrous metal foundry enterprises and evaluate the occupational health risks, and provide basis for policies of the formulation of pneumoconiosis prevention and control. Methods: From August to September in 2020, the basic information, dust hazard information and occupational health management information of 59 ferrous metal casting enterprises were investigated, the dust concentration distribution was analyzed, and the risk assessment was carried out by using the quantitative assignment model. The dust concentration is tested by LSD method after logarithmic treatment. The 3 times time weighted average allowable exposure concentration of dust is taken as the peak concentration limit of dust; The time weighted average allowable exposure concentration of dust converted by exposure time is taken as the time weighted average exposure concentration limit of dust, and whether the time weighted average exposure concentration and peak concentration of dust at the same post exceed the limit is taken as the basis for exceeding the limit of dust post concentration to calculate the post exceeding the limit rate. Results: The dust hazards were mainly distributed in the posts of sand treatment, molding, sand falling, sand cleaning and cutting and grinding. Dust exposure time weighted average concentration was 0.44 (0.03, 5.11) mg/m(3), peak exposure concentration was 1.30 (0.18, 10.94) mg/m(3), and the over standard rate of Posts was 38.92% (79/203) . Weighted average exposure concentration of other dust (total dust) in the cutting and grinding post is 1.50 (0.15, 7.40) mg/m(3), peak exposure concentration is 0.90 (0.07, 12.48) mg/m(3), and the post exceedance rate is 4.88% (2/41) . Weighted average exposure concentration of silica dust (exhaling dust) in dust operation posts of investment casting enterprises is 0.43 (0.05, 6.35) mg/m(3), peak exposure concentration is 0.90 (0.12, 8.28) mg/m(3), and the post over standard rate is 35.77% (49/137) ; Weighted average exposure concentration of other dust (total dust) at the cutting and grinding post is 2.00 (11.00, 21.00) mg/m(3), and the post exceedance rate is 2.50% (2/80) . There was no significant difference in the concentration of respirable dust between sand casting and investment casting (P>0.05) . The concentration of respirable dust in sand casting was higher than that in sand treatment, molding and sand cleaning posts (P<0.05) . The concentration of silica dust in investment casting was higher than that in sand treatment and molding posts, and that in sand cleaning posts was higher than that in sand treatment posts (P<0.05) . 98.48% (454/461) of the dust operation posts have an occupational health risk value greater than or equal to 400, and 1.52% (7/461) of the dust operation posts have an occupational health risk value of 200~399. Conclusion: there is a high rate of exceeding the standard in the dust work posts in the ferrous metal foundry enterprises in Ningbo, and the workers have a high occupational health risk of pneumoconiosis or metal and its compound pneumoconiosis. Targeted measures should be taken to reduce the occupational health risk.

[Transmission chains of local epidemic of COVID-19 caused by 2019-nCoV Delta variant in Zhenhai district, Ningbo]

Objective: To investigate the local epidemic of COVID-19 caused by 2019-nCoV Delta variant in Zhenhai district of Ningbo, identify the transmission chain and provide reference for the prevention and control of COVID-19 epidemic. Methods: The incidence data of COVID-19 in Zhenhai from 6 to 18 December, 2021 were collected in field investigation. Field epidemiological investigation was conducted to understand the epidemiological characteristics of COVID-19 cases and analyze the transmission chains. Results: The first case might be infected with 2019-nCoV through direct or indirect exposure when passing through a medium-risk area, then a family cluster was caused, and the epidemic spread through close contacts of family members with others such as work, daily life, and moxibustion. The epidemic lasted for 14 days, and 74 confirmed COVID-19 cases were reported. The median incubation period was 4.0(3.0,5.8)d. All the cases were in a chain of transmission for more than 6 generations, and the intergenerational interval was 3.5(2.0,5.3)d. The gene sequencing result indicated that the pathogen was Delta AY.4 variant of 2019-nCoV. Both the epidemiological investigation and the gene sequencing results supported that the local COVID-19 epidemic in Zhenhai was associated with the COVID-19 epidemic in Shanghai. Conclusions: The transmission chain of this epidemic was clear. Delta AY.4 variant has obvious characteristic to cause case clusters in families, places with poor ventilation, and residential communities. It is suggested to strengthen the health management in key areas and key populations, and increase the frequency of nucleic acid testing.

[Analysis of incidence characteristics and trend of pneumoconiosis in Ningbo City from 1967 to 2019]

Objective: To understand the incidence of pneumoconiosis in Ningbo city from 1967 to 2019, and to analyze the distribution characteristics and change trend of pneumoconiosis. Methods: In February 2021, the data of pneumoconiosis patients in Ningbo city from 1967 to 2019 were sorted out. The data from 1967 to 1987 were from historical case files of Zhejiang Center for Disease Control and Prevention, the data from 1988 to 2005 were from the historical case files of Ningbo Center for Disease Control and Prevention, and the data from 2006 to 2019 were from the pneumoconiosis report card in China Disease Prevention and Control Information System; Followed up and supplement relevant information, including basic information, basic information of employers and information related to pneumoconiosis diagnosis, and comprehensively analyze the composition and development trend, population characteristics and industry characteristics of pneumoconiosis. Results: From 1967 to 2019, a total of 1715 cases of pneumoconiosis were reported in Ningbo City, including 1254 cases of stageⅠpneumoconiosis, 258 cases of stageⅡpneumoconiosis, 172 cases of stage Ⅲpneumoconiosis. 1202 cases of silicosis (70.09%) , 296 cases of asbestosis (17.26%) , 40 cases of welder's pneumoconiosis (2.33%) , 32 cases of graphite pneumoconiosis (1.87%) were reported. There were 1296 male cases (75.57%) and 419 female cases (24.43%) were reported. Silicosis (91.15%, 1102/1209) and welder's pneumoconiosis (100.00%, 40/40) were the most common pneumoconiosis in males, while asbestosis (90.24%, 268/297) and graphite pneumoconiosis (87.50%, 28/32) were the most common pneumoconiosis in females. The average age was (49.71±10.90) years old and the average length of service was (10.98±6.96) years. The top three reported pneumoconiosis cases were construction industry (336 cases, 19.59%) , ferrous metal smelting and rolling industry (317 cases, 18.48%) and non-metallic mineral products industry (315 cases, 18.37%) . The top three reported pneumoconiosis cases were 414 cases (24.14%) in Ninghai County, 294 cases (17.14%) in Yuyao City and 272 cases (15.86%) in Yinzhou District. Conclusion: With the development of industries in Ningbo City, government departments should strengthen supervision and management of enterprises involving silica dust and welding fume to curb the high incidence of pneumoconiosis.

[Study on transmission dynamic of 15 clusters of COVID-2019 cases in Ningbo]

Objective: To describe the basic characteristics of clusters of coronavirus diseases 2019 (COVID-19) cases in Ningbo, Zhejiang province, and evaluate the generation time (Tg) and basic reproduction number (R(0)) of COVID-19. Methods: The basic information and onset times of the clusters of COVID-19 cases in Ningbo were investigated, the inter-generational interval of the cases were fitted by using gamma distribution, and the R(0) was calculated based on the SEIR model. Results: In the 15 clusters of COVID-19 cases, a total of 52 confirmed cases, 5 cases of nucleic acid-positive asymptomatic cases. The cases occurred from January 23 to February 4, the cases were mainly women. The incubation period was (6.11±3.38) days, and the median was 5 days. The Tg was (6.93±3.70) days. There were no significant differences in Tg between age group<60 years and age group 60 years and above, and between men and women (P=0.551). According to the Tg calculated in this paper, the R(0) of COVID-19 in Ningbo was 3.06 (95%CI: 2.64- 3.51); according to the reported case transmission interval of 7.5 days in the literature, the R(0) was 3.32 (95%CI: 2.51-9.38). Conclusion: There is no age and gender specific differences in the Tg of clusters of COVID-19 cases in Ningbo, and COVID-19 has high infectivity and spreading power in early phase.

[Observation on clinical effects of recombinant human growth hormone on the treatment of children with severe burn]

Objective: To observe the clinical effects of recombinant human growth hormone (rhGH) on children with severe burn. Methods: Clinical data of 94 children with severe burn, hospitalized in our burn unit from April 2012 to December 2016, conforming to the study criteria, were retrospectively analyzed. According to the use of rhGH, children were divided into rhGH group (n=50) and control group (n=44). Children in control group received conventional treatment, while children in rhGH group received both conventional and rhGH treatment. The rhGH treatment was started 3 to 5 days post injury in dosage of 0.2-0.4 U·kg(-1)·d(-1,) by way of subcutaneous injection, and the course of treatment was (11±5) d. The plasma albumin and prealbumin levels, heart rate, alanine aminotransferase (ALT), and serum creatinine level in 2 weeks post injury, times of skin grafting operation, hospitalization time, total hospitalization treatment cost, and sepsis and death of children were compared between the 2 groups. Data were processed with independent sample t test, Mann-Whitney U test, and Fisher's exact test. Results: (1) In 2 weeks post injury, the plasma albumin level [(36±4) g/L] and prealbumin level [(94±34) g/L] of children in rhGH group were significantly higher than those in control group [(33±4) and (73±20) g/L, t=3.666, 3.401, P<0.05]. (2) In 2 weeks post injury, the heart rate of children in rhGH group was (123±11) times per minute, which was slower than (130±14) times per minute of children in control group (t=2.839, P<0.05). There was no significant difference in ALT level of children between the 2 groups (Z=0.868, P>0.05). The blood creatinine levels of children in the 2 groups were within normal range. (3) The times of skin grafting operation of children in rhGH group was 0.3±0.5, which was significantly less than 0.5±0.6 in control group (Z=2.234, P<0.05). The hospitalization time of children in rhGH group was (22±8) days, which was shorter than (28±10) days in control group (t=2.837, P<0.05). The total hospitalization treatment cost of children in rhGH group was (41±15) thousand yuan, which was significantly less than (53±25) thousand yuan in control group (t=2.878, P<0.05). (4) There were 2 cases of sepsis in control group and 1 case of sepsis in rhGH group, with no significant difference between the 2 groups (P>0.05). No children died in the 2 groups. Conclusions: rhGH treatment of children with severe burn can correct post-injury hypoproteinemia, improve cardiac function, reduce the times of skin grafting operation and hospitalization treatment cost, shorten hospitalization time, with no significant effect on kidney and liver function, sepsis, and death.

Risk factors for poor outcome in posterior reversible encephalopathy syndrome: systematic review and meta-analysis

Background

The roles of clinical etiology and symptoms, imaging findings and biochemical parameters in predicting the prognosis of posterior reversible encephalopathy syndrome (PRES) have not been well-characterized. We perform a meta-analysis of all published studies to assess the value of various risk factors in predicting the prognosis of PRES.

Methods

Searches of the PubMed, EMBASE, Cochrane Library, and Web of Science databases were performed to identify the eligible studies. The odds ratios (ORs) with their corresponding 95% confidence interval (CI) for related risk factors were used to calculate the pooled estimates of the outcomes.

Results

Six studies with 448 cases were included in the meta-analysis. Hemorrhage was associated with high risk for poor outcome in patients with PRES. Toxemia of pregnancy (pre-eclampsia/eclampsia) was associated with improved outcome in PRES patients. Cytotoxic edema was noted to be related to poor outcome, but did not show statistical significance. The pooled OR for hemorrhage, pre-eclampsia/eclampsia, cytotoxic edema was 4.93 (95% CI: 3.94-6.17; P<0.00001), 0.24 (95% CI: 0.15-0.40; P<0.00001) and 2.59 (95% CI: 0.84-7.99; P=0.10), respectively.

Conclusions

PRES patients with hemorrhage or cytotoxic edema are likely to have poor outcomes. Pre-eclampsia/eclampsia is associated with reduced risk of poor outcome in patients with PRES.

[A cross-sectional study on the status of tobacco use among junior middle school students in Shaanxi province]

Objective: To understand the rate on tobacco use and associated factors in junior middle school students in Shaanxi province. Methods: We used a multi-stage stratified random sampling method to select students from 30 junior middle schools in 10 areas of Shaanxi province in 2013. All the participants completed a self-administered questionnaire. Results: A total of 4 633 questionnaires were dispatched and 4 298 were qualified for further analysis. The current smoking rate of junior middle school students in Shaanxi was 6.5%, with rate in male (11.1%) higher than that of female students (1.7%). The current smoking rate of students in grade three (9.3%) was higher than those of students in grade one (3.5%) or in grade two (7.0%). The smoking rate of students with pocket money more than 31 Yuan per week was (10.0%) higher than those of students with pocket money less than 10 Yuan (4.6%) or 10-30 Yuan (6.3%) per week. Results from the logistic regression analysis showed that factors as: male, school located in the city, older age, with more pocket money, having smokers in the family and exposure to second hand smoking were high risk factors for current smoking. Conclusion: Rate on current smoking was high in junior middle schools students in Shaanxi, suggesting that comprehensive intervention programs be developed to reduce the rate of tobacco use in junior middle school students.

Modulation of Tim-3 Expression by Antigen-Dependent and -Independent Factors on T Cells from Patients with Chronic Hepatitis B Virus Infection

T-cell immunoglobulin domain and mucin domain-containing molecule-3 (Tim-3) was up-regulated on viral specific T cells and contributed to T cells exhaustion during chronic hepatitis B virus (HBV) infection. However, modulation of Tim-3 expression was still not fully elucidated. To evaluate the potential viral and inflammatory factors involved in the inductor of Tim-3 expression on T cells, 76 patients with chronic HBV infection (including 40 chronic hepatitis B [CHB] and 36 asymptomatic HBV carriers [AsC]) and 40 of normal controls (NCs) were enrolled in this study. Tim-3 expressions on CD4⁺ and CD8⁺ T cells were assessed in response to HBV-encoding antigens, HBV peptide pools, and common γ-chain (γc) cytokines stimulation by flow cytometry. HBV peptides and anti-CD3/CD28 directly induced Tim-3 expression on T cells. γc cytokines also drive Tim-3 up-regulations on both CD4⁺ and CD8⁺ T cells in patients with chronic HBV infection. However, γc cytokines did not enhance the Tim-3 inductions by either anti-CD3/CD28 or HBV peptides stimulation. Furthermore, γc cytokines-mediated Tim-3 induction could not be abrogated by γc cytokine receptor-neutralizing antibodies. The current results suggested that elevation of Tim-3 expression on T cells could be regulated by both antigen-dependent and -independent manner in patients with chronic HBV infection. The role of γc cytokines in modulation of inhibitory pathway might be evaluated as immunotherapies in humans.

[Incidence and trend of occupational diseases in Ningbo, China, from 2006 to 2015]

Objective: To investigate the incidence, distribution features, and incidence trend of occupational diseases in Ningbo, China, from 2006 to 2015. Methods: In February 2016, the data on occupational disease report cards in the occupational disease and occupational health information system from 2006 to 2015 were collected to perform a comprehensive analysis of the types, incidence trend, population characteristics, and enterprise characteristics of occupational diseases. Results: There were 845 new cases of occupational diseases in Ningbo from 2006 to 2015, among which 596 (70.53%) were pneumoconiosis; there were 445 (74.66%) cases of stage I pneumoconiosis, 73 (12.25%) cases of stage II pneumoconiosis, and 78 (13.09%) cases of stage III pneumoconiosis; silicosis (59.76%) was the most common type of pneumoconiosis. Of all patients with occupational diseases, 84.97% were male, 64.50%were aged 35-55 years, and 63.67% had 5-20 working years. Most of the patients with occupational diseases worked in small and medium-sized private (or foreign) enterprises; the most common industries were black metal smelting and rolling (38.76%) , construction (17.11%) , and non-metallic ore mining (13.09%) . A total of 51.28%, 10.26%, and 7.69% of the patients with occupational poisoning worked in the electric apparatus manufacturing industry, furniture manufacturing industry, and chemical raw material and chemical product manufacturing industry, respectively. The cases of occupational diseases are mainly distributed in Yuyao City (24.62%) , Yinzhou District (23.91%) , and Ninghai County (15.62%) . Conclusion: Pneumoconiosis is the most common type of occupational disease in Ningbo and most of these patients work in small and medium-sized private (or foreign) enterprises. The supervision of small and medium-sized private enterprises should be enhanced to protect workers' health.

[The application of two occupation health risk assessment models in a wooden furniture manufacturing industry]

Objective: To explore the applicability of 2 different models of occupational health risk assessment in wooden furniture manufacturing industry. Methods: American EPA inhalation risk model and ICMM model of occupational health risk assessment were conducted to assess occupational health risk in a small wooden furniture enterprises, respectively. Results: There was poor protective measure and equipment of occupational disease in the plant. The concentration of wood dust in the air of two workshops was over occupational exposure limit (OEL) , and the C_TWA was 8.9 mg/m³ and 3.6 mg/m³, respectively. According to EPA model, the workers who exposed to benzene in this plant had high risk (9.7×10^-6 ~34.3×10^-6) of leukemia, and who exposed to formaldehyde had high risk (11.4 × 10^-6) of squamous cell carcinoma. There were inconsistent evaluation results using the ICMM tools of standard-based matrix and calculated risk rating. There were very high risks to be attacked by rhinocarcinoma of the workers who exposed to wood dust for the tool of calculated risk rating, while high risk for the tool of standard-based matrix. For the workers who exposed to noise, risk of noise-induced deafness was unacceptable and medium risk using two tools, respectively. Conclusion: Both EPA model and ICMM model can appropriately predict and assessthe occupational health risk in wooden furniture manufactory, ICMM due to the relatively simple operation, easy evaluation parameters, assessment of occupational- disease-inductive factors comprehensively, and more suitable for wooden furniture production enterprise.

[Relationship between weather factors and heat stroke in Ningbo city]

OBJECTIVE

To explore the main effects of weather factors on heat stroke.

METHODS

Data from case report on heat stroke was collected in Ningbo city during 2011 to 2014. Temperature threshold, lag effects and interaction of weather factors on heat stroke had been analyzed, using the piecewise regression model, distributed lag non-linear model, response surface model and other methods.

RESULTS

RESULTS showed that temperature and humidity were more correlated with heat stroke than other weather-related factors. Through different models, daily average temperature always presented a better role in predicting the heat stroke, rather than maximum or minimum temperature. Positive association between daily average temperature and heat stroke was obvious, especially at lag 0-1 days, with its threshold as 29.1 (95% CI: 28.7-29.5) ℃ . The cumulative RR of heat stroke at 90(th) percentile of daily average temperature versus 10(th) percentile was 14.05 (95% CI: 7.23-27.31) in lag 0-1 days. The effects of daily relative humidity on heat stroke appeared nonlinear, with low humidity showing a negative effect on heat stroke and could lag for 1-4 days. However, the effect of high humidity was not significant, with the cumulative RR of low humidity and high humidity as 2.35 (95%CI: 1.27-4.33) and 0.86 (95%CI: 0.40-1.85) in lag of 0-4 days, respectively. We also noticed that there was an interactive effect of both temperature and humidity on heat stroke. Under high temperature and low humidity, the risk of heat stroke showed the highest.

CONCLUSIONS

Temperature and humidity showed obvious relationship with heat stroke in Ningbo city, with the threshold temperature as 29.1 ℃. Under high temperature and low humidity, the risk of heat stroke became the highest.

Tumor necrosis factor-like weak inducer of apoptosis regulates the phenotype and cytotoxic activity of goat uterine natural killer cells

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) has an important role in the promotion of cell proliferation, migration, and differentiation. However, very little is known about the role of TWEAK in modulating uterine natural killer (uNK) cells' comprehensive functions in ruminants. In the present study, the effects of TWEAK on goat uNK cells were investigated by measuring their cytotoxic function and phenotype as well as cytokine expression in vitro. The results showed that TWEAK protein could be detected in the goat endometrium during estrous cycle and pregnancy. However, a significant increase in ( < 0.05) TWEAK protein levels was observed during very early pregnancy when compared with that during mid pregnancy and later pregnancy as well as during different phases of estrous cycle. Tumor necrosis factor-like weak inducer of apoptosis did not affect proliferation but did decrease ( < 0.05) the cytotoxic activity of uNK cells in vitro. Furthermore, the percentage of CD56/NKp46 uNK cells incubated with TWEAK-containing medium was greater ( < 0.05) compared with those treated with control medium. In addition, uNK cells incubated with TWEAK medium were associated with lesser ( < 0.05) secretion levels and protein expression of interferon-γ (IFN-γ) compared to those incubated with control medium. However, no differences ( > 0.05) could be observed for the secretion levels and protein expression of vascular endothelial growth factor (VEGF) in the uNK cells incubated with TWEAK-containing medium compared with those incubated with control medium. The present preliminary observations indicate that TWEAK has a biological effect on phenotype of uNK cells as well as the secretion and expression of IFN-γ by uNK cells in goats. Moreover, TWEAK decreases the cytotoxicity of goat uNK cells in vitro.

Silencing effect of lentiviral vectors encod-ing shRNA of Herp on endoplasmic reticulum stress and inflammatory responses in RAW 264.7 macrophages

Herp, a mammalian protein with a ubiquitin-like domain, can be strongly upregulated by endoplasmic reticulum (ER) stress during ER-associated protein degradation. However, the other cellular functions of Herp remain unclear. We explored the effect of Herp on ER stress and inflammatory responses in RAW 264.7 macrophages that had been exposed to tunicamycin or thapsigargin. We successfully constructed recombinant lentiviral vectors for Herp short-hairpin RNA (shRNA) expression to better understand the contribution made by Herp to other signaling pathways. Western blotting revealed that the recombinant Herp lentiviral shRNA vector significantly inhibited the expression of the Herp protein in the thapsigargin-treated RAW 264.7 macrophages. The reverse transcription quantitative polymerase chain reaction results showed that knockdown Herp inhibited the expression of ER stress-related genes during exposure to tunicamycin or thapsigargin. In RAW 264.7 macrophages, knockdown Herp markedly attenuated the expression of inflammatory cytokines when exposed to tunicamycin; however, it strongly enhanced the expression of inflammatory cytokines when exposed to thapsigargin. We concluded that Herp lentiviral shRNA vectors had been successfully constructed; knockdown Herp inhibited ER stress and had a different effect on inflammatory responses in RAW 264.7 macrophages depending on whether they were exposed to tunicamycin or thapsigargin.

Epidemiological studies of esophageal cancer in the era of genome-wide association studies

Esophageal cancer (EC) caused about 395000 deaths in 2010. China has the most cases of EC and EC is the fourth leading cause of cancer death in China. Esophageal squamous cell carcinoma (ESCC) is the predominant histologic type (90%-95%), while the incidence of esophageal adenocarcinoma (EAC) remains extremely low in China. Traditional epidemiological studies have revealed that environmental carcinogens are risk factors for EC. Molecular epidemiological studies revealed that susceptibility to EC is influenced by both environmental and genetic risk factors. Of all the risk factors for EC, some are associated with the risk of ESCC and others with the risk of EAC. However, the details and mechanisms of risk factors involved in the process for EC are unclear. The advanced methods and techniques used in human genome studies bring a great opportunity for researchers to explore and identify the details of those risk factors or susceptibility genes involved in the process of EC. Human genome epidemiology is a new branch of epidemiology, which leads the epidemiology study from the molecular epidemiology era to the era of genome wide association studies (GWAS). Here we review the epidemiological studies of EC (especially ESCC) in the era of GWAS, and provide an overview of the general risk factors and those genomic variants (genes, SNPs, miRNAs, proteins) involved in the process of ESCC.

Significance of combined detection of p53 and FHIT in cervical carcinoma diagnosis

PURPOSE

To explore the significance of combined detection of p53 genes and fragile histidine triad (FHIT) genes in cervical carcinoma.

MATERIALS AND METHODS

Specimens taken from 161 cases invasive carcinoma, 23 cases carcinoma in situ or cervical intraepithelial neoplasia III (CIN III), 74 cases CIN I - II, 25 cases normal cervical tissue, and 32 cases tumor-adjacent tissues were processed by immunohistochemistry to determine the expression of p53 and FHIT genes. The results of the combined detection were compared for clinical diagnostic value of cervical carcinoma diagnosis.

RESULTS

The p53 gene, FHIT gene and the two genes combined examination of cervical carcinoma diagnostic sensitivity were: 65.8% (121/184), 66.3% (122/184), 90.2% (166/184), respectively. There were no significant differences between the p53 gene and the FHIT gene detected (p > 0.05). Combined detection of the two gene were more sensitivity than single detection, the difference was significant (p < 0.001). Although diagnosis specificity had dropped somewhat, no significant statistical appeared (chi2 = 0.022, p > 0.05).

CONCLUSION

Combined detection of p53 genes and FHIT genes can increase the sensitivity diagnosis and specificity diagnosis for early cervical carcinoma and precancerous lesions has a positive meaning.

Normal evolution of pregnancy complicated by a giant placental chorioangioma

Placental chorioangioma is a benign vascular tumour of placental origin. Here The authors report a case of a pregnant patient who presented placental chorioangioma measuring 11 cm in the greatest diameter at 37 weeks at term and in labor.

Celecoxib radiosensitizes the human cervical cancer HeLa cell line via a mechanism dependent on reduced cyclo-oxygenase-2 and vascular endothelial growth factor C expression

OBJECTIVE

The effects of celecoxib, a selective cyclo-oxygenase-2 (COX-2) inhibitor, on HeLa cervical cancer cell growth and radiosensitivity were investigated.

METHODS

Cytotoxicity was quantified using a 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyltetrazolium assay and effects on radiosensitivity were assessed using the lethal dose, quasithreshold dose, fraction surviving after 2 Gy irradiation and the radiosensitization ratio (SER, based on average lethal dose) determined using a single-hit multitarget model.

RESULTS

Celecoxib inhibited HeLa cell proliferation in a concentration- and time-dependent manner, with a half-maximal inhibitory concentration at 72 h of 44 μmol/l. Treatment with 20 μmol/l celecoxib for 72 h before irradiation was associated with an SER of 2.01. The SER of irradiated cells was 2.41 when treated with 40 μmol/l celecoxib before irradiation, 1.89 when treated simultaneously and 1.44 when treated after irradiation. Celecoxib downregulated COX-2 and vascular endothelial growth factor C (VEGF-C) expression evaluated immunohistochemically.

CONCLUSION

Celecoxib pretreatment radiosensitizes HeLa cells via a mechanism dependent on down-regulation of COX-2 and VEGF-C.

Stromal-epithelial interactions modulate the effect of ovarian steroids on goat uterine epithelial cell interleukin-18 release

A primary role of epithelial-stromal interactions in mediating steroid hormone action in the uterus has been established. The present study was undertaken to determine the mode of ovarian steroid action in regulating IL-18 release by goat endometrial epithelial cells (EECs) in the presence and absence of endometrial stromal cells (ESCs). Primary and telomerase-immortalized goat EECs grown alone or cocultured with ESCs were treated with two ovarian steroids, 17β-estradiol (E(2)) and progesterone (P(4)). The IL-18 mRNA and protein expression in EECs were studied by reverse transcript (RT) PCR, ELISA, and Western blot assay. The E(2) and/or P(4) treatment of EECs led to a significant increase in both IL-18 mRNA and protein expression either in the primary or in the immortalized EECs compared with that in EECs without the steroid treatment. However, in the presence of ESCs, IL-18 expression by EECs treated with steroids was significantly decreased compared with cells untreated with E(2) and/or P(4). In addition, significantly high abundance of IL-18 mRNA and protein expression by primary and telomerase-immortalized goat EECs was observed in the presence of ESCs compared with those cells without ESCs. These findings suggest that steroids are important for the control of IL-18 expression in goat EECs. Underlying ESCs are needed to mediate the inhibitory effects of steroids on the IL-18 secretory activity of goat EECs in vitro. The IL-18 abundance expressed by goat EECs in vitro are enhanced by underlying ESCs without the treatment of E(2) and/or P(4).

Dietary and supplemental intake of one-carbon nutrients and the risk of type I and type II endometrial cancer: a prospective cohort study

BACKGROUND

Type I and II endometrial cancer are biologically and clinically distinct, with type II cancers having a high frequency of p53 mutations and an association with chromosomal instability. This raises the hypothesis that one-carbon nutrients (folate, methionine, and the enzymic cofactors vitamins B2, B6, and B12), which mediate chromosomal stability and DNA methylation, may be protective for type II but not type I endometrial cancer.

METHODS

Using a prospective cohort of 23 356 postmenopausal women followed 20 years, we estimated the relative risks (RRs) of type I (N = 471) and II (N = 71) endometrial cancers according to intake of one-carbon nutrients, adjusting for confounders.

RESULTS

No associations were observed between dietary or supplemental intake of any one-carbon nutrient and risk of type I cancer. For type II cancer, positive associations were due to supplemental, rather than dietary, intake of these nutrients: supplemental folate (RR = 1.80 for >228.6 versus 0 μg/day; P trend = 0.027) and vitamins B2 (RR = 1.94 for >1.70 versus 0 mg/day; P trend = 0.011), B6 (RR = 2.08 for >2.00 versus 0 mg/day; P trend = 0.012), and B12 (RR = 2.10 for >3.43 versus 0 μg/day; P trend = 0.0060).

CONCLUSION

Contrary to our hypothesis, use of supplements containing folate and vitamins B2, B6, and B12 was associated with an increased risk of type II endometrial cancer.

The distribution of species and susceptibility of amphotericin B and fluconazole of yeast pathogens isolated from sterile sites in Taiwan

To study the demographic changes of yeasts causing invasive infections in Taiwan, especially with respect to species distribution and antifungal susceptibility, we analyzed isolates obtained from four sterile sites of patients in 19 hospitals in 2002 (155 strains) and again from the same hospitals in 2006 (208 strains). Blood was the most common source of the yeasts, accounting for 73.8% of the total isolates, followed by ascites (21.5%), cerebrospinal fluid (3%), and synovia (1.7%). Candida albicans was the most frequently recovered species (50.1% of the total), followed by Candida tropicalis (20.7%), Candida glabrata (11.6%), Candida parapsilosis (8.5%), Cryptococcus neoformans (3.9%), Candida krusei (0.8%), and nine other species (4.3%). There were one (0.3%) and seven (1.9%) isolates with minimum inhibitory concentrations (MICs) of amphotericin B > or =2 mg/l after 24 h and 48 h incubation, respectively. In addition, there were 15 (4.3%) and 31 (8.6%) isolates with MICs of fluconazole > or =64 mg/l under the same conditions. The MIC(90) value of amphotericin B was 1 mg/l. The MIC(90) values of fluconazole were 4 mg/l after 24 h incubation and 32 mg/l after 48 h incubation. Interestingly, MICs for fluconazole > or =64 mg/l after 24 h were significantly higher for isolates obtained in 2006 than those in 2002 after 24 h (7.1% vs. 0.7%, p =0.009) and 48 h (13.5% vs. 2%, p =0.0003) incubations. The demographic difference between these two surveys is mainly due to one species, C. tropicalis.

Characterization of yeasts colonizing in healthy individuals

Opportunistic yeast pathogens may switch from harmless commensal to pathogenic relationships with the host under different conditions. They usually cause superficial infections, but may be the agents of more significant infections in immunocompromised patients. To investigate yeast colonization in the oral cavities of clinically healthy individuals, we collected oral swabs from 323 students and staff at the National Health Research Institutes, Taiwan. A total of 49 (15.2%) volunteers were colonized by low levels of yeasts and of these, only 3 (6.1%) were co-colonized by more than one species. Among the 52 isolates, comprising seven fungal genera and 13 species, Candida albicans (57.7%) was the dominant species, followed by Candida parapsilosis (15.4%). There was only one isolate of C. parapsilosis that showed, in vitro, a high (2 μg/ml) minimum inhibitory concentration (MIC) to amphotericin B. There were six (11.5%) isolates with fluconazole MICs ≥ 64 μg/ml and all of them were non-Candida species. With the exception of Cryptococcus albidus, the remaining five isolates had voriconazole MICs ≥ 4 μg/ml. In addition, there was one C. albicans isolate with relatively high fluconazole (32 μg/ml) and voriconazole (4 μg/ml) MICs.

Experience-dependent plasticity in hypocretin/orexin neurones: re-setting arousal threshold

The neuropeptide hypocretin is synthesized exclusively in the lateral hypothalamus and participates in many brain functions critical for animal survival, particularly in the promotion and maintenance of arousal in animals - a core process in animal behaviours. Consistent with its arousal-promoting role in animals, the neurones synthesizing hypocretin receive extensive innervations encoding physiological, psychological and environmental cues and send final outputs to key arousal-promoting brain areas. The activity in hypocretin neurones fluctuates and correlates with the behavioural state of animals and intensive activity has been detected in hypocretin neurones during wakefulness, foraging for food and craving for addictive drugs. Therefore, it is likely that hypocretin neurones undergo experience-dependent changes resulting from intensive activations by stimuli encoding changes in the internal and external environments. This review summarizes the most recent evidence supporting experience-dependent plasticity in hypocretin neurones. Current data suggest that nutritional and behavioural factors lead to synaptic plasticity and re-organization of synaptic architecture in hypocretin neurones. This may be the substrate of enhanced levels of arousal resulting from behavioural changes in animals and may help to explain the mechanisms underlying the changes in arousal levels induced by physiological, psychological and environmental factors.

Characterization, physicochemical properties and biocompatibility of La-incorporated apatites

In this study, the physicochemical properties and biocompatibilities of La-containing apatites were intensively investigated together with their characterizations in terms of composition, structure, valent state and morphology using X-ray diffraction, Fourier-transform infrared spectra, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. The results indicate that the La(3+) ion can be incorporated into the crystal lattice of hydroxyapatite resulting in the production of La-incorporated apatites (La(x)Ca(10-x)(PO(4))(6)(OH)(2+x-2y)O(y square y-x) (x> or =0.5, y<1+x/2) or La(x)Ca(10-x)(PO(4))(6)O(y square y-x) (0.5<x<2, y=1+x/2)) by high-temperature solid phase synthesis. For La content <20%, the product is composed of the major phase, La(x)-OAP, as well as a small amount of tricalcium phosphate, but for a La content of 20%, the product is pure La-incorporated oxyapatite with the formula La(2)Ca(8)(PO(4))(6)O(2) (La(2)-OAP, x=2, y=2). It is also found that the La content plays important roles in both the physicochemical properties and biocompatibilities of the La-incorporated apatites. In contrast to La-free apatite, La-incorporated apatites possess a series of attractive properties, including higher thermal stability, higher flexural strength, lower dissolution rate, larger alkaline phosphatase activity, preferable osteoblast morphology and comparable cytotoxicity. In particular, the sintered La-incorporated apatite block achieves a maximal flexure strength of 66.69+/-0.98 MPa at 5% La content (confidence coefficient 0.95), increased 320% in comparison with the La-free apatite. The present study suggests that the La-incorporated apatite possesses application potential in developing a new type of bioactive coating material for metal implants and also as a promising La carrier for further exploring the beneficial functions of La in the human body.

A new cell culture system for infection with hepatitis B virus that fuses HepG2 cells with primary human hepatocytes

Hepatitis B virus (HBV) infection exhibits a very narrow host range and shows a strong tropism for liver parenchymal cells, however none of the previously established experimental models can reproduce the natural process of HBV infection. In the present study, primary human hepatocytes were fused with HepG2 cells to establish the hybrid HepCHLine-4 cell line with high susceptibility to HBV. The HepCHLine-4 cells expressed HBV-specific antigen when co-incubated with HBV-positive serum from a hepatitis B patient. Post-infection, HBV relaxed circular DNA and covalently closed circular DNA were detected in HepCHLine-4 cells using a nested polymerase chain reaction, and HBV-specific particles were visualized by electron microscopy of the culture media of HepCHLine-4 cells. HepG2 cells were not susceptible to HBV infection under the same conditions. The HepCHLine-4 cells can be sub-cultured for > 12 months while maintaining susceptibility to HBV and may, therefore, be useful for studying HBV infection and the viral life cycle in human hepatocytes.

Image segmentation feature selection and pattern classification for mammographic microcalcifications

Since microcalcifications in X-ray mammograms are the primary indicator of breast cancer, detection of microcalcifications is central to the development of an effective diagnostic system. This paper proposes a two-stage detection procedure. In the first stage, a data driven, closed form mathematical model is used to calculate the location and shape of suspected microcalcifications. When tested on the Nijmegen University Hospital (Netherlands) database, data analysis shows that the proposed model can effectively detect the occurrence of microcalcifications. The proposed mathematical model not only eliminates the need for system training, but also provides information on the borders of suspected microcalcifications for further feature extraction. In the second stage, 61 features are extracted for each suspected microcalcification, representing texture, the spatial domain and the spectral domain. From these features, a sequential forward search (SFS) algorithm selects the classification input vector, which consists of features sensitive only to microcalcifications. Two types of classifiers-a general regression neural network (GRNN) and a support vector machine (SVM)--are applied, and their classification performance is compared using the Az value of the Receiver Operating Characteristic curve. For all 61 features used as input vectors, the test data set yielded Az values of 97.01% for the SVM and 96.00% for the GRNN. With input features selected by SFS, the corresponding Az values were 98.00% for the SVM and 97.80% for the GRNN. The SVM outperformed the GRNN, whether or not the input vectors first underwent SFS feature selection. In both cases, feature selection dramatically reduced the dimension of the input vectors (82% for the SVM and 59% for the GRNN). Moreover, SFS feature selection improved the classification performance, increasing the Az value from 97.01 to 98.00% for the SVM and from 96.00 to 97.80% for the GRNN.

Genetic susceptibility and environmental factors of esophageal cancer in Xi’an

AIM: To analyse the role of genetic susceptibility and environmental factors in the process of esophageal cancer (EC) formation in Xi’an, China.

METHODS: A hospital based case-control study, combined with molecular epidemiological method, was carried out. A total of 127 EC cases and 101 controls were interviewed with questionnaires containing demographic items, habit of tobacco smoking, alcohol drinking, and family history of EC. Polymorphism of CYP1A1 and GSTM1 of 127 EC cases and 101 controls were detected by PCR method. The interactions between genetic susceptibility and environmental factors were also discussed.

RESULTS: Tobacco smoking, alcohol drinking and a family history of EC were risk factors for EC with an OR of 2.04 (95%CI 1.15-3.60), 3.45(95%CI 1.74-6.91), 3.14 (95%CI 1.28-7.94), respectively. Individuals carrying CYP1A1 Val/Val genotype compared to those with CYP1A1 Ile/Ile genotype had an increased risk for EC (OR 3.35, 95%CI 1.49-7.61). GSTM1 deletion genotype was a risk factor for EC (OR1.81, 95%CI 1.03-3.18). Gene-environment interaction analysis showed that CYP1A1 Val/Val genotype, GSTM1 deletion genotype had synergetic interactions with tobacco smoking, alcohol drinking and family history of EC.

CONCLUSION: Tobacco smoking, alcohol drinking and a family history of EC are risk factors for EC. CYP1A1 Val/Val and GSTM1 deletion genotypes are genetic susceptibility biomarkers for EC. There are synergic interactions between genetic susceptibility and environmental factors.

Relationship of tobacco smoking CYP1A1 GSTM1 gene polymorphism and esophageal cancer in Xi'an

AIM

To analyze the association of tobacco smoking polymorphism of CYP1A1 (7th exon) and GSTM1 genotype and esophageal cancer(EC) in Xi'an.

METHODS

A hospital based case-control study, with molecular epidemiological method, was carried out. Polymorphism of CYP1A1 and GSTM1 of samples from 127 EC cases and 101 controls were detected by PCR method.

RESULTS

There were no significant difference of age and gender between cases and controls. Tobacco smoking was the main risk factor OR=1.97;95% CI=1.12-3.48 for EC in Xi'an. The proportions of CYP1A1 Ile/Ile, Ile/Val and Val/Val gene types in cases and controls was 19.7% 45.7% 34.6% and 30.7%,47.5%, 21.8% respectively(P=0.049). Individuals with CYP1A1 Val/Val genotype compared to those with CYP1A1 Ile/Ile genotype had higher risk for EC increased (OR=2.48, 95%CI=1.12-5.54). The proportions of GSTM1 deletion genotype in cases and controls were 58.3% and 43.6%(OR=1.81, 95%CI=1.03-3.18, P=0.028). Analysis of gene-environment interaction showed that tobacco smoking and CYP1A1 Val/Val genotype; tobacco smoking and GSTM1 deletion genotype had synergism interaction respectively. Analysis of gene-gene interaction did not find synergistic interaction between these two genes. But in GSTM1 deletion group there was significant difference of distribution of CYP1A1 genotype between cases and controls (P=0.011).

CONCLUSION

CYP1A1 Val/Val and GSTM1 deletion genotypes are genetic susceptibility biomarkers for EC. The risk increases, when person with CYP1A1 Val/Val and/or GSTM1 deletion genotype. And these two-metabolic enzymes seem to have interactions with tobacco smoking, in which the mechanism still needs further study.

Class II histone deacetylases: structure, function, and regulation

Acetylation of histones, as well as non-histone proteins, plays important roles in regulating various cellular processes. Dynamic control of protein acetylation levels in vivo occurs through the opposing actions of histone acetyltransferases and histone deacetylases (HDACs). In the past few years, distinct classes of HDACs have been identified in mammalian cells. Class I members, such as HDAC1, HDAC2, HDAC3, and HDAC8, are well-known enzymatic transcriptional corepressors homologous to yeast Rpd3. Class II members, including HDAC4, HDAC5, HDAC6, HDAC7, and HDAC9, possess domains similar to the deacetylase domain of yeast Hdal. HDAC4, HDAC5, and HDAC7 function as transcriptional corepressors that interact with the MEF2 transcription factors and the N-CoR, BCoR, and CtBP corepressors. Intriguingly, HDAC4, HDAC5, and probably HDAC7 are regulated through subcellular compartmentalization controlled by site-specific phosphorylation and binding of 14-3-3 proteins; the regulation of these HDACs is thus directly linked to cellular signaling networks. Both HDAC6 and HDAC9 possess unique structural modules, so they may have special biological functions. Comprehension of the structure, function, and regulation of class II deacetylases is important for elucidating how acetylation regulates functions of histones and other proteins in vivo.

Effects of polyamines on the thermal stability and formation kinetics of DNA duplexes with abnormal structure

The effects of ions (i.e. Na+, Mg2+ and polyamines including spermidine and spermine) on the stability of various DNA oligonucleotides in solution were studied. These synthetic DNA molecules contained sequences that mimic various cellular DNA structures, such as duplexes, bulged loops, hairpins and/or mismatched base pairs. Melting temperature curves obtained from the ultraviolet spectroscopic experiments indicated that the effectiveness of the stabilization of cations on the duplex formation follows the order of spermine > spermidine > Mg2+ > Na+ > Tris-HCl buffer alone at pH 7.3. Circular dichroism spectra showed that salts and polyamines did not change the secondary structures of those DNA molecules under study. Surface plasmon resonance (SPR) observations suggested that the rates of duplex formation are independent of the kind of cations used or the structure of the duplexes. However, the rate constants of DNA duplex dissociation decrease in the same order when those cations are involved. The enhancement of the duplex stability by polyamines, especially spermine, can compensate for the instability caused by abnormal structures (e.g. bulged loops, hairpins or mismatches). The effects can be so great as to make the abnormal DNAs as stable as the perfect duplex, both kinetically and thermodynamically. Our results may suggest that the interconversion of various DNA structures can be accomplished readily in the presence of polyamine. This may be relevant in understanding the role of DNA polymorphism in cells.

Mechanism of product chain length determination and the role of a flexible loop in Escherichia coli undecaprenyl-pyrophosphate synthase catalysis

The Escherichia coli undecaprayl-pyrophosphate synthase (UPPs) structure has been solved using the single wavelength anomalous diffraction method. The putative substrate-binding site is located near the end of the betaA-strand with Asp-26 playing a critical catalytic role. In both subunits, an elongated hydrophobic tunnel is found, surrounded by four beta-strands (betaA-betaB-betaD-betaC) and two helices (alpha2 and alpha3) and lined at the bottom with large residues Ile-62, Leu-137, Val-105, and His-103. The product distributions formed by the use of the I62A, V105A, and H103A mutants are similar to those observed for wild-type UPPs. Catalysis by the L137A UPPs, on the other hand, results in predominantly the formation of the C(70) polymer rather than the C(55) polymer. Ala-69 and Ala-143 are located near the top of the tunnel. In contrast to the A143V reaction, the C(30) intermediate is formed to a greater extent and is longer lived in the process catalyzed by the A69L mutant. These findings suggest that the small side chain of Ala-69 is required for rapid elongation to the C(55) product, whereas the large hydrophobic side chain of Leu-137 is required to limit the elongation to the C(55) product. The roles of residues located on a flexible loop were investigated. The S71A, N74A, or R77A mutants displayed 25-200-fold decrease in k(cat) values. W75A showed an 8-fold increase of the FPP K(m) value, and 22-33-fold increases in the IPP K(m) values were observed for E81A and S71A. The loop may function to bridge the interaction of IPP with FPP, needed to initiate the condensation reaction and serve as a hinge to control the substrate binding and product release.

Histone deacetylase 4 possesses intrinsic nuclear import and export signals

Nucleocytoplasmic trafficking of histone deacetylase 4 (HDAC4) plays an important role in regulating its function, and binding of 14-3-3 proteins is necessary for its cytoplasmic retention. Here, we report the identification of nuclear import and export sequences of HDAC4. While its N-terminal 118 residues modulate the nuclear localization, residues 244 to 279 constitute an authentic, strong nuclear localization signal. Mutational analysis of this signal revealed that three arginine-lysine clusters are necessary for its nuclear import activity. As for nuclear export, leucine-rich sequences located in the middle part of HDAC4 do not function as nuclear export signals. By contrast, a hydrophobic motif (MXXLXVXV) located at the C-terminal end serves as a nuclear export signal that is necessary for cytoplasmic retention of HDAC4. This motif is required for CRM1-mediated nuclear export of HDAC4. Furthermore, binding of 14-3-3 proteins promotes cytoplasmic localization of HDAC4 by both inhibiting its nuclear import and stimulating its nuclear export. Unlike wild-type HDAC4, a point mutant with abrogated MEF2-binding ability remains cytoplasmic upon exogenous expression of MEF2C, supporting the notion that direct MEF2 binding targets HDAC4 to the nucleus. Therefore, HDAC4 possesses intrinsic nuclear import and export signals for its dynamic nucleocytoplasmic shuttling, and association with 14-3-3 and MEF2 proteins affects such shuttling and thus directs HDAC4 to the cytoplasm and the nucleus, respectively.

Crystallographic analysis of a novel complex of actinomycin D bound to the DNA decamer CGATCGATCG

The potent anticancer drug actinomycin D (ActD) acts by binding to DNA, thereby interfering with replication and transcription. ActD inhibits RNA polymerase far more specifically than DNA polymerase. Such discrimination is not easily understood by the conventional DNA binding mode of ActD. We have solved and refined at 1.7 A resolution the crystal structure of ActD complexed to CGATCGATCG, which contains no canonical GpC binding sequence. The crystal data are space group P4(3)2(1)2, a = b = 47.01 A, and c = 160.37 A. The structure was solved by the multiple wavelength anomalous diffraction method using a 5-bromo-U DNA. The asymmetric unit of the unit cell contains two independent dimers of a novel slipped duplex complex consisting of two decamer DNA strands bound with two ActD drug molecules. (The DNA in one dimer is numbered C1 to G10 in one strand and C11 to G20 in the complementary strand and in the second dimer, C101 to G110 and C111 to G120, respectively.) The structure reveals a highly unusual ActD binding mode in which the DNA adopts a slipped duplex with the A3-T4/A13-T14 dinucleotides looped out. ActD intercalates between G2-C11* (C11* being from a symmetry-related molecule) and C5-G20 base pairs. Two such slipped duplex-ActD complexes bound to each other by mutually intercalating their T4/T14 bases into the helix cavities (located between C5-G20 and G6-C19 base pairs) of neighboring complexes, forming a dimer of drug-DNA complexes. The binding site mimics the drug binding at the elongation point during transcription. Modeling studies show that the ActD-DNA complex fits snugly in the active site cavity in RNA polymerase but not in DNA polymerase. This may explain the strong preference of ActD inhibition toward transcription.

Ramosetron for the management of chemotherapy-induced gastrointestinal events in patients with hematological malignancies

The objective of this study was to evaluate the efficacy and safety of ramosetron hydrochloride for the management of nausea and vomiting induced by chemotherapy in patients with hematological malignancies. A total of 30 patients with hematological malignancies were included in the ramosetron group. Ramosetron (0.3 mg i.v.) was administered 0.5 h before chemotherapy. The impact of ramosetron on anorexia, nausea and vomiting as well as other adverse effects were assessed. Meanwhile, another 39 patients received tropisetron (o.d. for 3 days). As compared to the tropisetron group, the response rate of the ramosetron group in controlling anorexia within 18-24 h after chemotherapy was higher (p < 0.05); within 18-24 h after chemotherapy, the complete response rate and effective rate in controlling nausea was higher (p < 0.05); within 12-18 h and 18-24 h after chemotherapy, the complete response rate and effective rate in controlling vomiting was higher (p < 0.05). The incidence of adverse effects was similar in both groups. We conclude that ramosetron belongs to a new generation of 5-HT3 receptor antagonists and that it is a safe, economic and effective antiemetic drug.

Histone deacetylase 4 associates with extracellular signal-regulated kinases 1 and 2, and its cellular localization is regulated by oncogenic Ras

Histone deacetylase 4 (HDAC4) is a member of a family of enzymes that catalyze the removal of acetyl groups from core histones, resulting in a compact chromatin structure that is generally associated with repressed gene transcription. Protein phosphorylation has been implicated in the regulation of the corepressor activity of the deacetylase. Here we report that serine/threonine kinases are found in association with HDAC4 and phosphorylate HDAC4 in vitro, and HDAC4 is phosphorylated in cells. The extracellular signal-regulated kinases 1 and 2 (ERK1/2), also known as p44(MAPK) and p42(MAPK), respectively, are two of the kinases associated with HDAC4. ERK1/2 are components of the Ras-mitogen-activated protein kinase (MAPK) signal transduction pathway. Activation of the Ras-MAPK pathway by expression of oncogenic Ras or constitutively active MAPK/ERK kinase 1 results in an increased percentage of cells (from approximately 10% to approximately 70%) that express HDAC4 in the nucleus in C2C12 myoblast cells. In cells transfected with oncogenic Ras, nuclear HDAC4 is associated with kinase activity. Our results provide evidence that protein kinase activity is present in a protein complex with HDAC4 and directly links the Ras-MAPK signal transduction pathway to a mechanism for chromatin remodeling (i.e., histone deacetylation).

The structure of aspartyl dipeptidase reveals a unique fold with a Ser-His-Glu catalytic triad

The three-dimensional structure of Salmonella typhimurium aspartyl dipeptidase, peptidase E, was solved crystallographically and refined to 1.2-A resolution. The structure of this 25-kDa enzyme consists of two mixed beta-sheets forming a V, flanked by six alpha-helices. The active site contains a Ser-His-Glu catalytic triad and is the first example of a serine peptidase/protease with a glutamate in the catalytic triad. The active site Ser is located on a strand-helix motif reminiscent of that found in alpha/beta-hydrolases, but the polypeptide fold and the organization of the catalytic triad differ from those of the known serine proteases. This enzyme is a member of a family of serine hydrolases and appears to represent a new example of convergent evolution of peptidase activity.

Crystal structures of the chromosomal proteins Sso7d/Sac7d bound to DNA containing T-G mismatched base-pairs

Sso7d and Sac7d are two small chromatin proteins from the hyperthermophilic archaeabacterium Sulfolobus solfataricus and Sulfolobus acidocaldarius, respectively. The crystal structures of Sso7d-GTGATCGC, Sac7d-GTGATCGC and Sac7d-GTGATCAC have been determined and refined at 1.45 A, 2.2 A and 2.2 A, respectively, to investigate the DNA binding property of Sso7d/Sac7d in the presence of a T-G mismatch base-pair. Detailed structural analysis revealed that the intercalation site includes the T-G mismatch base-pair and Sso7d/Sac7d bind to that mismatch base-pair in a manner similar to regular DNA. In the Sso7d-GTGATCGC complex, a new inter-strand hydrogen bond between T2O4 and C14N4 is formed and well-order bridging water molecules are found. The results suggest that the less stable DNA stacking site involving a T-G mismatch may be a preferred site for protein side-chain intercalation.

Binding of a macrocyclic bisacridine and ametantrone to CGTACG involves similar unusual intercalation platforms

The binding of a macrocyclic bisacridine and an antitumor intercalator ametantrone to DNA has been studied. We carried out X-ray diffraction analyses of the complexes between both intercalators and CGTACG. We have determined the crystal structure, by the multiple-wavelength anomalous diffraction (MAD) method, of bisacridine complexed with CGTA[br(5)C]G at 1.8 A resolution. The refined native crystal structure at 1.1 A resolution (space group C222, a = 29.58 A, b = 54.04 A, c = 40.22 A, and R-factor = 0.163) revealed that only one acridine of the bisacridine drug binds at the C5pG6 step of the DNA, with the other acridine plus both linkers completely disordered. Surprisingly, both terminal G.C base pairs are unraveled. The C1 nucleotide is disordered, and the G2 base is bridged to its own phosphate P2 through a hydrated Co(2+) ion. G12 is swung toward the minor groove with its base stacked over the backbone. The C7 nucleotide is flipped away from the duplex part and base paired to a 2-fold symmetry-related G6. The central four base pairs adopt the B-DNA conformation. An unusual intercalator platform is formed by bringing four complexes together (involving the 222 symmetry) such that the intercalator cavity is flanked by two sets of G x C base pairs (i.e., C5 x G8 and G6 x C7) on each side, joined together by G6 x G8 tertiary base pairing interactions. In the bisacridine-CGTACG complex, the intercalation platform is intercalated with two acridines, whereas in the ametantrone-CGTACG complex, only one ametantrone is bound. NMR titration of the bisacridine to AACGATCGTT suggests that the bisacridine prefers to bridge more than one DNA duplex by intercalating each acridine to different duplexes. The results may be relevant in understanding binding of certain intercalators to DNA structure associated with the quadruplet helix and Holliday junction.

Regulation of histone deacetylase 4 by binding of 14-3-3 proteins

Histone (de)acetylation is important for the regulation of fundamental biological processes such as gene expression and DNA recombination. Distinct classes of histone deacetylases (HDACs) have been identified, but how they are regulated in vivo remains largely unexplored. Here we describe results demonstrating that HDAC4, a member of class II human HDACs, is localized in the cytoplasm and/or the nucleus. Moreover, we have found that HDAC4 interacts with the 14-3-3 family of proteins that are known to bind specifically to conserved phosphoserine-containing motifs. Deletion analyses suggested that S246, S467, and S632 of HDAC4 mediate this interaction. Consistent with this, alanine substitutions of these serine residues abrogated 14-3-3 binding. Although these substitutions had minimal effects on the deacetylase activity of HDAC4, they stimulated its nuclear localization and thus led to enhanced transcriptional repression. These results indicate that 14-3-3 proteins negatively regulate HDAC4 by preventing its nuclear localization and thereby uncover a novel regulatory mechanism for HDACs.

Ultra-high resolution DNA structures

This paper describes the progress in our efforts at producing ultra-high resolution (< 0.8 A) DNA structures using advanced cryo-crystallography and synchrotron. Our work is aimed at providing reliable geometric (bond length and bond angle), electronic and motional information of DNA molecules in different conformational contexts. These highly-reliable, new structures will be the basis for constructing better DNA force-field parameters, which will benefit the structural refinement of DNA, protein-DNA complexes, and ligand-DNA complexes.

Photoreactivity of 5-iodouracil-containing DNA-Sso7d complex

X-ray structure of DNA-Sso7d complex indicated that binding of this protein causes sharp DNA bending. In order to examine whether this protein also causes DNA bending in solution, photoreactions of 1U-substituted DNA in the presence and the absence of Sso7d protein were investigated. It was found that the unusual intrastrand hydrogen abstraction at methyl of adjacent thymine occurred efficiently at the observed bending site of crystal structure.