Genome-wide association studies and Mendelian randomization analyses provide insights into the causes of early-onset colorectal cancer

BACKGROUND

The incidence of early-onset colorectal cancer (EOCRC; diagnosed <50 years of age) is rising globally; however, the causes underlying this trend are largely unknown. CRC has strong genetic and environmental determinants, yet common genetic variants and causal modifiable risk factors underlying EOCRC are unknown. We conducted the first EOCRC-specific genome-wide association study (GWAS) and Mendelian randomization (MR) analyses to explore germline genetic and causal modifiable risk factors associated with EOCRC.

PATIENTS AND METHODS

We conducted a GWAS meta-analysis of 6176 EOCRC cases and 65 829 controls from the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), the Colorectal Transdisciplinary Study (CORECT), the Colon Cancer Family Registry (CCFR), and the UK Biobank. We then used the EOCRC GWAS to investigate 28 modifiable risk factors using two-sample MR.

RESULTS

We found two novel risk loci for EOCRC at 1p34.1 and 4p15.33, which were not previously associated with CRC risk. We identified a deleterious coding variant (rs36053993, G396D) at polyposis-associated DNA repair gene MUTYH (odds ratio 1.80, 95% confidence interval 1.47-2.22) but show that most of the common genetic susceptibility was from noncoding signals enriched in epigenetic markers present in gastrointestinal tract cells. We identified new EOCRC-susceptibility genes, and in addition to pathways such as transforming growth factor (TGF) β, suppressor of Mothers Against Decapentaplegic (SMAD), bone morphogenetic protein (BMP) and phosphatidylinositol kinase (PI3K) signaling, our study highlights a role for insulin signaling and immune/infection-related pathways in EOCRC. In our MR analyses, we found novel evidence of probable causal associations for higher levels of body size and metabolic factors-such as body fat percentage, waist circumference, waist-to-hip ratio, basal metabolic rate, and fasting insulin-higher alcohol drinking, and lower education attainment with increased EOCRC risk.

CONCLUSIONS

Our novel findings indicate inherited susceptibility to EOCRC and suggest modifiable lifestyle and metabolic targets that could also be used to risk-stratify individuals for personalized screening strategies or other interventions.

Primary human thyrocytes maintained the function of thyroid hormone production and secretion in vitro

PURPOSE

Thyroid cell lines are useful tools to study the physiology and pathology of the thyroid, however, they do not produce or secrete hormones in vitro. On the other hand, the detection of endogenous thyroid hormones in primary thyrocytes was often hindered by the dedifferentiation of thyrocytes ex vivo and the presence of large amounts of exogenous hormones in the culture medium. This study aimed to create a culture system that could maintain the function of thyrocytes to produce and secrete thyroid hormones in vitro.

METHODS

We established a Transwell culture system of primary human thyrocytes. Thyrocytes were seeded on a porous membrane in the inner chamber of the Transwell with top and bottom surfaces exposed to different culture components, mimicking the 'lumen-capillary' structure of the thyroid follicle. Moreover, to eliminate exogenous thyroid hormones from the culture medium, two alternatives were tried: a culture recipe using hormone-reduced serum and a serum-free culture recipe.

RESULTS

The results showed that primary human thyrocytes expressed thyroid-specific genes at higher levels in the Transwell system than in the monolayer culture. Hormones were detected in the Transwell system even in the absence of serum. The age of the donor was negatively related to the hormone production of thyrocytes in vitro. Intriguingly, primary human thyrocytes cultured without serum secreted higher levels of free triiodothyronine (FT3) than free thyroxine (FT4).

CONCLUSION

This study confirmed that primary human thyrocytes could maintain the function of hormone production and secretion in the Transwell system, thus providing a useful tool to study thyroid function in vitro.

Global burden of neoplasms attributable to specific occupational carcinogens over 30 years: a population-based study

OBJECTIVES

The study aimed to analyze the global burden of occupational neoplasms from various epidemiological perspectives.

STUDY DESIGN

In this cross-sectional study, secondary analyses were conducted to assess the burden of neoplasms attributable to occupational carcinogens and their distribution characteristics using data from GBD 2019 and the World Bank database.

METHODS

Based on the GBD 2019 and the World Bank database, we analyzed the global burden of occupational neoplasms including the age-period-cohort model, decomposition analysis, health inequality analysis, and panel model. All analyses were conducted in R (version 4.0.3) and Joinpoint (version 4.9.1).

RESULTS

The absolute number of neoplasms burden attributable to occupational carcinogens has continued to rise over 30 years. In 2019, occupational neoplasms caused 333,867 [95% uncertainty interval (UI): 263,491 to 404,641] mortalities and 6,964,775 (95% UI: 5,467,884 to 8,580,431) disability-adjusted life years (DALYs) globally. Greenland, Monaco, the Netherlands, and Andorra suffered the highest burden. The burden was higher in countries with a higher sociodemographic index. The age effect was prominent in the elderly, and the 1925 birth cohort had the highest cohort effect. Population growth was the most significant driver of the mortalities (89%) and DALYs (111%) change. Moreover, the proportion of urban population was significantly positively associated with the disease burden, while GDP per capita was negatively correlated with the disease burden.

CONCLUSIONS

The burden of occupational neoplasms was unevenly distributed across locations and populations. The need for rational allocation of healthcare resources was urgent.

[Predictive value of low-density lipoprotein cholesterol/remnant cholesterol coordination on cardiovascular and cerebrovascular events in elderly patients with hypertension]

Objective: To explore the predictive value of serum low-density lipoprotein cholesterol/residual cholesterol (LDL-C/RC) coordination on major adverse cardiovascular events (MACE) in elderly hypertensive patients. Methods: This is a prospective cohort study. Elderly hypertensive patients hospitalized in Beijing Anzhen Hospital from June 2018 to June 2020 were prospectively enrolled. According to the coordination of baseline LDL-C/RC, patients were divided into four groups: low LDL-C and low RC (LDL-C<2.6 mmol/L, and RC<0.62 mmol/L), low LDL-C and high RC (LDL-C<2.6 mmol/L, and RC≥0.62 mmol/L), high LDL-C and low RC (LDL-C≥2.6 mmol/L, and RC<0.62 mmol/L), and high LDL-C and high RC (LDL-C≥2.6 mmol/L, and RC≥0.62 mmol/L). Patients were followed up until June 2022. The primary outcome was MACE, including non-fatal acute coronary syndrome, non-fatal acute heart failure, non-fatal stroke and death. Kaplan-Meier survival analysis was used to evaluate MACE among the four groups, and Cox regression analysis was performed to evaluate the related factors of MACE. Results: A total of 847 hypertensive patients were enrolled. There were 453 males (53.5%), mean age was (72.4±8.8) years. There were 207, 162, 263, 215 patients in the low LDL-C and low RC, low LDL-C and high RC, high LDL-C and low RC and high LDL-C and high RC group, respectively. During a median follow-up of 37 months, 196 patients (23.1%) had MACE, including 77 cases (9.1%) of ACS, 56 cases (6.6%) of acute heart failure, 34 cases (4.0%)of non-fatal stroke, 29 cases(3.4%) of all-cause mortality, and 16 cases (1.9%) of cardiovascular death. Risk of MACE of the four groups was significantly different (log-rank P<0.001). Compared with low LDL-C and low RC groups, high LDL-C and high RC groups had the highest incidence of MACE (HR=2.237, 95%CI 1.328-3.783, P=0.004), followed by low LDL-C and high RC groups (HR=1.745, 95%CI 1.220-2.527, P=0.003) and high LDL-C and low RC groups (HR=1.393, 95%CI1.048-1.774, P=0.022). In addition, the risk of nonfatal ACS among the four groups was also statistically significant (P=0.037), while the risk of nonfatal acute heart failure, nonfatal stroke, all-cause mortality and cardiovascular death were similar (all P>0.05). Multivariate Cox regression analysis showed that age (HR=1.271), duration of hypertension (HR=1.339), diabetes (HR=1.415), hyperlipidemia (HR=1.348), serum creatinine (HR=1.263), N-terminal pro-B-type natriuretic peptide (HR=1.316), LDL-C (HR=1.205), RC (HR=1.302), low LDL-C and high RC (HR=1.745), high LDL-C and low RC (HR=1.393), high LDL-C and high RC (HR=2.237) were independently associated with the occurrence of MACE. Conclusion: The coordination of LDL-C/RC affects the risk of MACE in elderly hypertensive patients, and the risk of MACE is the highest in patients with high LDL-C and high RC.

Erratum: Momentum-Resolved Observation of Thermal and Quantum Depletion in a Bose Gas [Phys. Rev. Lett. 117, 235303 (2016)]

This corrects the article DOI: 10.1103/PhysRevLett.117.235303.

[Comparison on the clinical characteristics of patients with Takotsubo syndrome from China and from Europe/North America]

Objective: To summarize the clinical characteristics of patients with Takotsubo syndrome (TTS) from China and compare these features with patients from Europe/North America. Methods: We reviewed case reports published between 1990 and 2020 with the key words of "Takotsubo syndrome" "stress cardiomyopathy" "apical balloon syndrome" and "broken heart syndrome", in Wanfang, CNKI, Pubmed and Web of Science databases, and 1 294 articles were identified, including 128 articles reporting 163 cases in China and 1 166 articles reporting 1 256 cases in Europe/North America. The characteristics of demographics, triggers, symptoms, electrocardiogram, echocardiography, left ventriculogram,coronary angiography, treatment and prognosis were analyzed and compared between Chinese and European/North American cases. Results: A total of 1 294 articles (1 419 cases: 163 from China, 1 256 from Europe/North America) were included in the final analysis. The characteristics of Chinese cases included: (1) demographic:the age was (59.6±16.9) years, which was similar with that of European/North American ((59.7±17.4) years, P=0.90), and female accounting for 78.5% (128/163), which was lower than that of European/North American (85.4% (1 073/1 256), P=0.02). (2) Triggers:mental triggers accounted for 48.5% (79/163), physical triggers accounted for 43.6% (71/163), and no triggers accounted for 7.9% (13/163), respectively. Compared with Europe/North America, the ratio of patients with mental triggers was higher in China, while the ratio of patients with physical triggers and no triggers was lower (P<0.05). (3) Symptoms: chest pain (52.8% (86/163)), chest tightness (35.0% (57/163)), shortness of breath (33.1% (54/163)), dizziness (16.0% (26/163)), sweating (15.3% (25/163)), palpitations (12.3% (20/163)), syncope (9.2% (15/163)) abdominal pain/diarrhea (8.6% (14/163)), hypotension (7.4% (12/163)), and fatigue (1.2% (2/163)) were illustrated in sequence. Compared with patients in Europe/North America, the ratio of patients with chest tightness, dizziness, sweating, palpitations, abdominal pain/diarrhea was higher in Chinese patients, while the ratio of patients with hypotension was lower in Chinese patients (P<0.05). (4) Electrocardiogram: main manifestations were myocardial ischemia symptoms, such as ST-segment elevation (63.8% (104/163)), T wave inversion (46.0% (75/163)), ST-segment depression (8.6% (14/163)). Compared with European/North American, the ratio of patients with ST-segment elevation, T wave inversion, and atrioventricular block was higher in Chinese patients (P<0.05). (5) Echocardiography and imaging:apical dyskinesia (59.5% (97/163)) and apical/left ventricular bulbar dilation (36.2%(59/163)) dominated the echocardiography findings. Compared with European/North American, the ratio of patients with apical dyskinesia, apical/left ventricular bulbar dilation, and mitral regurgitation was higher in Chinese patients, while the ratio of patients with dyskinesia in other parts and left ventricular ejection fraction<50% was lower in Chinese patients (P<0.05). Left ventricular angiography showed 36.2% (59/163) of apical dyskinesia in Chinese patients, which was higher than that reported in European/North American patients, and 38.7% (63/163) of apical/left ventricular bulbar dilation was reported in Chinese patients, which was similar to that reported in European/North American patients. Coronary angiography showed percent of no stenosis or stenosis less than 50% was 87.1% (142/163), which was similar to that reported in European/North American patients (P>0.05). The typical type of TTS accounted for 96.3% (157/163), which was significantly higher than that reported in European/ American patients, while the ratio of basal type and midventricular type was lower (P<0.01). (6) Treatment and prognosis:the applied drugs in China were listed in order as following, β-blockers (41.1% (67/163)), antiplatelet agents (37.4%(61/163)), ACEI/ARB (36.2%(59/163)), anticoagulants (27.0%(44/163)), diuretics (19.6% (32/163)), etc. Compared with Europe/North America, the ratio of antiplatelet agents, anticoagulants, statins, diuretics, and nitrates use was higher in China (P<0.05), while the use of oxygen therapy and IABP was similar (P>0.05). The hospital mortality in China was 5.5% (9/163), during 1-year follow-up the recurrence rate was 3.7% (6/163) and the mortality was 0. The prognosis was similar with that in Europe/North America. Conclusions: Compared with TTS cases in Europe/North America, TTS cases in China also occur usually in middle-aged and elderly women, most of whom have mental/physical triggers and typical imaging manifestations, followed by a low hospital mortality rate and recurrence rate.

External validation of the HCM Risk-Kids model for predicting sudden cardiac death in childhood hypertrophic cardiomyopathy

Background

Sudden cardiac death (SCD) is the most common mode of death in childhood hypertrophic cardiomyopathy (HCM). The newly developed HCM Risk-Kids model provides clinicians with individualised estimates of risk. The aim of this study was to externally validate the model in a large independent, multi-centre patient cohort.

Methods

A retrospective, longitudinal cohort of patients diagnosed with HCM aged 1–16 years independent of the HCM-Risk-Kids development and internal validation cohort was studied. Data on HCM Risk-Kids predictor variables (unexplained syncope, non-sustained ventricular tachycardia, maximal left ventricular wall-thickness, left atrial diameter and left ventricular outflow tract gradient) were collected from the time of baseline clinical evaluation. The performance of the HCM Risk-Kids model in predicting risk at 5 years was assessed.

Results

The cohort consisted of 421 patients with a median age at baseline evaluation of 12.3 years (IQR 7.3, 14.4). Over a median total follow up 3.48 years (IQR 1.83, 6.62, range 1 month – 20.7 years). Fourteen patients (3.3%) died and 10 (2.4%) underwent cardiac transplantation. Twenty-three patients (5.4%) met the SCD end-point within 5-years, with an overall incidence rate of 2.03 per 100 patient years (95% CI 1.48–2.78). Model validation showed a Harrell's C-index of 0.745 (95% CI 0.52–0.97) and Uno's C-index 0.714 (95% 0.58–0.85) with a calibration slope of 1.15 (95% 0.51–1.80). Figure 1a describes the agreement between predicted and observed 5-year cumulative proportion of SCD or equivalent events for each tertile of predicted risk in one imputed data set. One hundred and twenty-five (29.7%) patients had a predicted 5-year risk of ≥6%. SCD events occurred in 6 patients (2.0%) with a predicted risk &lt;6% and 17 (13.6%) with a predicted risk ≥6. A 5-year predicted risk threshold of ≥6% identified 17 (73.9%) SCD-events with a corresponding C-statistic of 0.702 (95% CI 0.60–0.81) (Figure 1b).

Conclusions

This study reports the first external validation of the HCM Risk-Kids model in a large and geographically diverse patient population. A 5-year predicted risk of ≥6% identified over 70% of events, confirming that HCM Risk-Kids provides a method for individualised risk predictions and shared decision making in children with HCM. Incorporation of the model into routine clinical care will enable independent prospective model validation and assessment of the effect of its use in clinical practice.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): British Heart FoundationMedical Research Council Observed vs predicted risk by tertilesObserved vs predicted by threshold

[Advances in indocyanine green fluorescence imaging during hepatectomy]

While surgical operation is the preferred treatment for liver malignancies,the postoperative recurrence rate remains high. In the early 21^st century,Japanese scientists first reported the use of indocyanine green(ICG) in liver resection. Follow-up studies also found its potential applications such as identifying tumors,determining surgical margins,delineating segmental boundaries,and preventing bile leakage. At present,ICG fluorescence imaging is applied to some types of hepatectomy with excellent effect and is expected to assist in generating surgical strategies for liver malignancies. However,its safety and efficacy still need further studies to evaluate.

[The comparison of prognosis and risk factors after radical resection for pancreatic ductal adenocarcinoma between China Pancreas Data Center and SEER]

Objectives: To compare the prognosis of patients underwent radical resection for pancreatic ductal adenocarcinoma(PDAC) in Surveillance, Epidemiology, and End Results(SEER) and China Pancreas Data Center(CPDC), and to compare the prognostic factors for PDAC in both databases. Methods: The data of patients underwent radical resection for PDAC in CPDC database from January 2016 to December 2017 and SEER database from January 2014 to December 2015 were retrospectively analyzed. The prognosis of patients in both databases was analyzed by the Kaplan-Meier method, Log-rank method, and propensity score matching, and the Cox proportional hazard regression was used to analyze the independent prognosis factors for PDAC. Results: There were 1 977 cases and 2 220 cases of pancreatic cancer that underwent radical resection from CPDC and SEER, respectively. There were more male patients(60.90%,1 204/1 977) than female patients(39.10%,773/1 977) in CPDC, while nearly 1∶1 ratio(male:1 112 cases,female:1108)was observed between male and female in SEER(χ²=48.977,P<0.01). The proportion of patients under 45 years old was the smallest in both databases, and the age group with the most significant proportion was 60 to 74 years old. The ratio of patients over 75 years old in the SEER(24.28%,539/2 220) was higher than that of CPDC(7.89%,156/1 977)(χ²=202.090,P<0.01), while the proportion of patients between 45 and 59 years old in CPDC(33.69%,666/1 977) was higher than that in SEER(19.77%,439/2 220)(χ²=103.640,P<0.01). There were more pancreatic head cancers than body and tail cancers in both databases, and no statistical difference was found in tumor size between the two databases (W=2 181 502,P=0.740). More positive and examined lymph nodes were found in SEER patients (W=3 265 131,W=2 954 363,all P<0.01); and the proportion of patients who had at least 15 lymph nodes dissected was higher in SEER(63.24%,1 404/2 220)(χ²=532.130,P<0.01). There were more patients without neoadjuvant or adjuvant therapy in CPDC(57.16%,1 130/1 977) than that in SEER(24.91%,553/2 220)(χ²=451.390,P<0.01). After propensity score matching, the overall survival for CPDC was better than that for SEER(Log-rank test:χ²=4.500,P=0.034), and the median overall survival was 24 months and 23 months respectively. Cox regressional analysis showed the common independent prognosis factors in both databases were ≥75 years old, pancreatic head cancer, poorly differentiated and undifferentiated tumors, T stage, N stage(All P<0.05). Neoadjuvant or adjuvant therapy was a protective factor in both databases(CPDC:Wald=27.082;SEER:Wald=212.285, all P<0.01) and 45 to 59 years old was protective factor in the SEER database(Wald=5.212,P=0.020). Conclusions: The data in both databases have a good consistency. However, in terms of data quality, examined lymph nodes count, and neoadjuvant/adjuvant therapy rate, the CPDC differs greatly from the SEER.

Study on Catalytic Oxidation, Flocculation and Sedimentation of Acidizing and Fracturing Wastewater

The acidizing and fracturing waste fluid in a wellsite in northern Shaanxi was treated by catalytic oxidation and flocculation precipitation. It investigated the effect of different coagulants and their dosage and the wastewater pH on coagulation precipitation. As for chemical oxidation experiment, it investigated the effect of oxidant dosage and reaction time on its treatment effect. The results showed that when 30% hydrogen peroxide (volume percentage) was added at the dosage of 0.3% and oxidized for 50 min, the pH was adjusted to 7.5 and 350 mg/L polyaluminum chloride (PAC) and 4 mg/L polyacrylamide were added (PAM); after processing the waste liquid, total iron, chemical oxygen demand (COD), chromaticity, and average corrosion rate were reduced from 252.75 mg/L, 3427.50 mg/L, 624.15°, and 0.1226 mm/a to 0.12 mg/L, 275.18 mg/L, 125° and 0.0217 mm/a, respectively; effective removal of iron and color, reduced COD, and controlled corrosion was achieved.

[A comparative study on the construction methods of animal models of aortic arch dissection]

Objective: To compare the effectiveness and safety of different methods to construct animal models of aortic arch dissection (AAD), and explore safe and effective methods for constructing AAD animal models. Methods: Twenty-four healthy mongrel dogs were divided into 4 groups by random number table (n=6). Group A: Venous incision needle high pressure water flow impact method; Group B: Venous incision needle non-high pressure water flow impact method; Group C: Transarterial sheath non-high pressure water flow impact method; Group D: Two-way balloon expansion combined with elastase perfusion method. Imaging examinations were performed immediately and 7 days after operation, aortic tissue biopsy and pathological staining were performed 15 days after operation to observe the formation of AAD. The operation time, aortic blood flow block time, model construction success rate, dissection tear length, postoperative survival rate and survival time of four groups of experimental dogs were collected to compare the effectiveness and safety of different construction methods. Results: There were no significant difference of the gender, age and weight between four groups of experimental dogs (all P>0.05). The operation time of four groups of experimental dogs were (111.6±8.0), (168.0±17.4), (164.4±13.9), (202.8±21.5)min, and the difference was statistically significant (F=39.973, P<0.001). The operation time of group A was significantly lower than group B, C and D (all P<0.001). The aortic blood flow block time of four groups of experimental dogs were (5.2±1.8), (19.6±3.8), (20.6±3.9), and (18.6±3.0) min, and the difference was statistically significant (all P<0.001). The aortic blood flow block time of group A was significantly lower than group B, C and D (F=27.598, P<0.001). The four groups of experimental dogs had 5, 5, 4, and 1 model were successfully constructed, respectively, and the difference was statistically significant (P=0.008). The successful rate of model construction in group A was significantly higher than that in group D (P=0.040). The dissection tear length of four groups were (14.4±3.0), (11.3±4.2), (7.0±2.3), (4.7±0.6) cm,and the difference was statistically significant (F=8.103, P=0.003). The dissection tear length of group A was significantly longer than group C, D (all P<0.05). The postoperative survival time were 15.0(10.0, 15.0), 5.0(3.0, 10.0), 3.5(1.5, 4.8), 10.0(2.8, 15.0) days, and the difference was statistically significant (χ²=7.825,P=0.036). The postoperative survival time of group A was significantly higher than group B, C (all P<0.05). There was no significant difference in the survival rate of the four groups (P=1.000). The pathological staining results showed that the elastic fiber at the tearing point of AAD was destroyed, and the elastic fiber on the outer wall of the false cavity was over-stretched, which was consistent with the pathological changes of aortic dissection. Conclusion: Transvenous incision needle high-pressure water flow impact modeling method is easy to operate. The aortic blood flow block time is short, the dissection tear length is wide, and the postoperative survival time is long, can be used as the preferred method of animal AAD model construction.

Molecular Evolution of Maize Ascorbate Peroxidase Genes and Their Functional Divergence

Ascorbate peroxidase (APX) is an important antioxidant enzyme. APXs in maize are encoded by multiple genes and exist as isoenzymes. The evolutionary history and functional divergence of the maize APX gene family were analyzed through comparative genomic and experimental data on the Internet in this paper. APX genes in higher plants were divided into classes A, B, and C. Each type of APX gene in angiosperms only had one ancestral gene that was duplicated along with the genome duplication or local (or tandem) duplication of the angiosperm. A total of eight genes were retained in maize and named APXa1, APXa2, APXa3, APXb1, APXb2, APXc1.1, APXc1.2, and APXc2. The APX genes of class A were located in the chloroplasts or mitochondria, and the class B and C genes were localized in the peroxisomes and cytoplasm, respectively. The expression patterns of eight APXs were different in vegetative and reproductive organs at different growth and development stages. APXa1 and APXb1 of maize may participate in the antioxidant metabolism of vegetative organs under normal conditions. APXa2, APXb2, APXc1.1, and APXc1.2 may be involved in the stress response, and APXb2 and APXc2 may participate in the senescence response. These results provide a basis for cultivating high-yield and resistant maize varieties.

[Manual suture or stapler closure: management of pancreatic stump during distal pancreatectomy]

Postoperative pancreatic fistula is the most common complication after distal pancreatectomy.With the update of the domestic and international guidelines or consensuses, the definition of pancreatic fistula has become more standardized.And the classification of pancreatic fistula is able to represent the severity of clinical outcomes more accurately.Currently, the determination of risk factors of pancreatic fistula after distal pancreatectomy, the establishment of prediction model, and the surgical closure mode of pancreatic stump still remain the major topics.With the rapid development of laparoscopic and robotic surgery in pancreatectomy, there are more and more selectionsin transection and managing the pancreatic stump after distal pancreatectomy for prevention of pancreatic fistula.However, there has not been a uniform fashion in terms of manual suture or stapler use to close the pancreatic stump.Herein the current status and development of pancreatic fistula after distal pancreatectomy are reviewed.The strategy of managing the pancreatic stump after distal pancreatectomy should be adopted individually according to the texture and thickness of pancreatic parenchyma.

Resveratrol protects against oxidative damage of retinal pigment epithelium cells by modulating SOD/MDA activity and activating Bcl-2 expression

OBJECTIVE

Age-related macular degeneration (AMD) is mainly characterized by dysfunction of retinal pigment epithelium (RPE) cells. This study aimed to investigate the protective effects of resveratrol on oxidative damaged RPE cells.

MATERIALS AND METHODS

Human D407 cells were divided into normal control (NC), H2O2 treated (H2O2, treating with H2O2 at a final concentration of 200 mol/l) and resveratrol treatment groups (treating with resveratrol at a concentration of 12.5, 25, 50 and 100 mg/l). Malondialdehyde (MDA) and superoxide dismutase (SOD) activities were examined using enzyme-linked immunosorbent assay (ELISA). 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and cell count kit-8 (CCK-8) were used to examine cell viability. Cell cycle phase distribution and apoptosis of D407 cells were evaluated using flow cytometry assay. B-cell lymphoma-2 (Bcl-2) and cleaved caspase 3 expression were detected using quantitative real-time PCR (qRT-PCR) and Western blot assay, respectively.

RESULTS

Resveratrol significantly decreased inhibitive ratios of D407 cell growth compared to that of H2O2 group (p<0.05). Resveratrol significantly increased SOD activity compared to that of H2O2 group (p<0.05). Resveratrol significantly reduced MDA activity compared to that of H2O2 group (p<0.05). Resveratrol affected cell cycle phase distribution of D407 cells compared to that of H2O2 group (p<0.05). Resveratrol significantly decreased the early stage and late stage apoptosis rates compared to that of H2O2 group (p<0.05). Resveratrol significantly enhanced Bcl-2 levels and decreased cleaved caspase 3 levels compared to that of H2O2 group (p<0.05).

CONCLUSIONS

Resveratrol protected against the oxidative damage of RPE cells by modulating SOD/MDA activity and activating Bcl-2 expression.

Inelastic vibrational dynamics of CS in collision with H2 using a full-dimensional potential energy surface

We report a six-dimensional (6D) potential energy surface (PES) for the CS-H2 system computed using high-level electronic structure theory and fitted using a hybrid invariant polynomial method. Full-dimensional quantum close-coupling scattering calculations have been carried out using this potential for rotational and, for the first time, vibrational quenching transitions of CS induced by H2. State-to-state cross sections and rate coefficients for rotational transitions in CS from rotational levels j1 = 0-5 in the ground vibrational state are compared with previous theoretical results obtained using a rigid-rotor approximation. For vibrational quenching, state-to-state and total cross sections and rate coefficients were calculated for the vibrational transitions in CS(v1 = 1,j1) + H2(v2 = 0,j2) → CS(v1' = 0,j1') + H2(v2' = 0,j2') collisions, for j1 = 0-5. Cross sections for collision energies in the range 1 to 3000 cm-1 and rate coefficients in the temperature range of 5 to 600 K are obtained for both para-H2 (j2 = 0) and ortho-H2 (j2 = 1) collision partners. Application of the computed results in astrophysics is also discussed.

Cerium Improves Growth of Maize Seedlings via Alleviating Morphological Structure and Oxidative Damages of Leaf under Different Stresses

It had been indicated that cerium (Ce) could promote maize growth involving photosynthetic improvement under potassium (K) deficiency, salt stress, and combined stress of K⁺ deficiency and salt stress. However, whether the improved growth is related to leaf morphological structure, oxidative stress in maize leaves is not well understood. The present study showed that K⁺ deficiency, salt stress, and their combined stress inhibited growth of maize seedlings, affecting the formation of appendages of leaf epidermal cells, and stomatal opening, which may be due to increases in H₂O₂ and malondialdehyde levels, and reductions in Ca²⁺ content, ratios of glutathione/oxidized glutathione, ascorbic acid/dehydroascorbic acid, and the activities of superoxide dismutase, catalase, ascorbic acid peroxidase, guaiacol peroxidase, and glutathione reductase in leaves under different stresses. The adverse effects caused by combined stress were higher than those of single stress. Furthermore, our findings demonstrated that adding Ce³⁺ could significantly promote seedling growth, and alleviate morphological and structural damage of leaf, decrease oxidative stress and increase antioxidative capacity in maize leaves caused by different stresses.

Altered expression of chondroitin sulfate structure modifying sulfotransferases in the articular cartilage from adult osteoarthritis and Kashin-Beck disease

OBJECTIVE

To investigate the expression of enzymes involved in chondroitin sulfate (CS) sulfation in the articular cartilage isolated from adult patients with osteoarthritis (OA) and Kashin-Beck disease (KBD), using normal adults as controls.

METHODS

Articular cartilage samples were collected from normal, OA and KBD adults aged 38-60 years old, and divided into three groups with six individual subjects in each group. The morphology and pathology grading of knee joint cartilage was examined by Safranin O staining. The localization and expression of enzymes involved in CS sulfation (CHST-3, CHST-11, CHST-12, CHST-13, carbohydrate (N-acetylgalactosamine 4-sulfate 6-O) sulfotransferase 15 - CHST-15, and uronyl 2-O-sulfotransferase - UST) were examined by immunohistochemical (IHC) staining and semi-quantitative analysis.

RESULTS

Positive staining rates for anabolic enzymes CHST-3, CHST-12, CHST-15, and UST were lower in the KBD and OA groups than those in the control group. Meanwhile, reduced levels of CHST-11, and CHST-13 in KBD group were observed, in contrast to those in OA and control groups. The expressions of all six CS sulfation enzymes were less detected in the superficial and deep zones of KBD cartilage compared with control and OA cartilage.

CONCLUSION

The reduced expression of the CS structure modifying sulfotransferases in the chondrocytes of both KBD and OA adult patients may provide explanations for their cartilage damages, and therapeutic targets for their treatment.

Momentum-Resolved Observation of Thermal and Quantum Depletion in a Bose Gas

We report on the single-atom-resolved measurement of the distribution of momenta ℏk in a weakly interacting Bose gas after a 330 ms time of flight. We investigate it for various temperatures and clearly separate two contributions to the depletion of the condensate by their k dependence. The first one is the thermal depletion. The second contribution falls off as k^{-4}, and its magnitude increases with the in-trap condensate density as predicted by the Bogoliubov theory at zero temperature. These observations suggest associating it with the quantum depletion. How this contribution can survive the expansion of the released interacting condensate is an intriguing open question.

Effect of the Suboccipital Musculature on Symptom Severity and Recovery after Mild Traumatic Brain Injury

BACKGROUND AND PURPOSE

Neck musculature mass has been suggested as a biomechanical contributor to injury severity in mild traumatic brain injury. We sought to determine how the cross-sectional areas of the suboccipital muscles affect symptom severity, neurocognitive performance, and recovery time in patients with mild traumatic brain injury.

MATERIALS AND METHODS

Sixty-four consecutive patients with mild traumatic brain injury underwent MR imaging and serial neurocognitive testing with the Immediate Post-Concussion Assessment and Cognitive Test. Cross-sectional areas of the rectus capitis posterior musculature were retrospectively obtained at C1, and cross-sectional areas of the remaining 7 suboccipital muscles were measured at C2. Cross-sectional area reproducibility was evaluated. Overall and individual muscle cross-sectional areas were correlated with symptom severity, neuropsychological testing, recovery time, and headache.

RESULTS

Sixty-four patients with mild traumatic brain injury had imaging through C1, and 43 had imaging through C2. Reproducibility of cross-sectional area measurements was substantial (correlation coefficients = 0.9517-0.9891). Lower cross-sectional area of the rectus capitis posterior minor was correlated with greater symptom severity (r = 0.596, P < .0001), longer recovery time (r = 0.387, P = .002), poor verbal memory performance (r = 0.285, P = .02), and headache (r = 0.39, P = .001). None of the other cross-sectional areas were associated with symptom severity, recovery time, neurocognitive testing, or headache.

CONCLUSIONS

In mild traumatic brain injury, the rectus capitis posterior minor is the only suboccipital muscle whose cross-sectional area is associated with symptom severity and worse outcome. Given the unique connection of this muscle to the dura, this finding may suggest that pathology of the myodural bridge contributes to symptomatology and prognosis in mild traumatic brain injury.

Poly-ADP-ribosylation-mediated degradation of ARTD1 by the NLRP3 inflammasome is a prerequisite for osteoclast maturation

Evidence implicates ARTD1 in cell differentiation, but its role in skeletal metabolism remains unknown. Osteoclasts (OC), the bone-resorbing cells, differentiate from macrophages under the influence of macrophage colony-stimulating factor (M-CSF) and receptor-activator of NF-κB ligand (RANKL). We found that M-CSF induced ADP-ribosyltransferase diphtheria toxin-like 1 (ARTD1) auto-ADP-ribosylation in macrophages, a modification that marked ARTD1 for cleavage, and subsequently, for degradation upon RANKL exposure. We established that ARTD1 proteolysis was NLRP3 inflammasome-dependent, and occurred via the proteasome pathway. Since ARTD1 is cleaved at aspartate²¹⁴, we studied the impact of ARTD1 rendered uncleavable by D214N substitution (ARTD1^D214N) on skeletal homeostasis. ARTD1^D214N, unlike wild-type ARTD1, was resistant to cleavage and degradation during osteoclastogenesis. As a result, ARTD1^D214N altered histone modification and promoted the abundance of the repressors of osteoclastogenesis by interfering with the expression of B lymphocyte-induced maturation protein 1 (Blimp1), the master regulator of anti-osteoclastogenic transcription factors. Importantly, ARTD1^D214N-expressing mice exhibited higher bone mass compared with controls, owing to decreased osteoclastogenesis while bone formation was unaffected. Thus, unless it is degraded, ARTD1 represses OC development through transcriptional regulation.

Gene expression profiling analysis of lung adenocarcinoma

The present study screened potential genes related to lung adenocarcinoma, with the aim of further understanding disease pathogenesis. The GSE2514 dataset including 20 lung adenocarcinoma and 19 adjacent normal tissue samples from 10 patients with lung adenocarcinoma aged 45-73 years was downloaded from Gene Expression Omnibus. Differentially expressed genes (DEGs) between the two groups were screened using the t-test. Potential gene functions were predicted using functional and pathway enrichment analysis, and protein-protein interaction (PPI) networks obtained from the STRING database were constructed with Cytoscape. Module analysis of PPI networks was performed through MCODE in Cytoscape. In total, 535 upregulated and 465 downregulated DEGs were identified. These included ATP5D, UQCRC2, UQCR11 and genes encoding nicotinamide adenine dinucleotide (NADH), which are mainly associated with mitochondrial ATP synthesis coupled electron transport, and which were enriched in the oxidative phosphorylation pathway. Other DEGs were associated with DNA replication (PRIM1, MCM3, and RNASEH2A), cell surface receptor-linked signal transduction and the enzyme-linked receptor protein signaling pathway (MAPK1, STAT3, RAF1, and JAK1), and regulation of the cytoskeleton and phosphatidylinositol signaling system (PIP5K1B, PIP5K1C, and PIP4K2B). Our findings suggest that DEGs encoding subunits of NADH, PRIM1, MCM3, MAPK1, STAT3, RAF1, and JAK1 might be associated with the development of lung adenocarcinoma.

Tunable spin-orbit coupling via strong driving in ultracold-atom systems

Spin-orbit coupling is an essential ingredient in topological materials, conventional and quantum-gas-based alike. Engineered spin-orbit coupling in ultracold-atom systems-unique in their experimental control and measurement opportunities-provides a major opportunity to investigate and understand topological phenomena. Here we experimentally demonstrate and theoretically analyze a technique for controlling spin-orbit coupling in a two-component Bose-Einstein condensate using amplitude-modulated Raman coupling.

Coordinated interaction of Down syndrome cell adhesion molecule and deleted in colorectal cancer with dynamic TUBB3 mediates Netrin-1-induced axon branching

Modulation of actin and microtubule (MT) dynamics in neurons is implicated in guidance cue-dependent axon outgrowth, branching and pathfinding. Although the role of MTs in axon guidance has been well known, how extracellular guidance signals engage MT behavior in axon branching remains unclear. Previously, we have shown that TUBB3, the most dynamic β-tubulin isoform in neurons, directly binds to deleted in colorectal cancer (DCC) to regulate MT dynamics in Netrin-1-mediated axon guidance. Here, we report that TUBB3 directly interacted with another Netrin-1 receptor Down syndrome cell adhesion molecule (DSCAM) and Netrin-1 increased this interaction in primary neurons. MT dynamics were required for Netrin-1-promoted association of DSCAM with TUBB3. Knockdown of either DSCAM or DCC or addition of a function blocking anti-DCC antibody mutually blocked Netrin-1-induced interactions, suggesting that DSCAM interdependently coordinated with DCC in Netrin-1-induced binding to TUBB3. Both DSCAM and DCC were partially colocalized with TUBB3 in the axon branch and the axon branching point of primary neurons and Netrin-1 increased these colocalizations. Netrin-1 induced the interaction of endogenous DSCAM with polymerized TUBB3 in primary neurons and Src family kinases (SFKs) were required for regulating this binding. Knockdown of DSCAM only, DCC only or both was sufficient to block Netrin-1-induced axon branching of E15 mouse cortical neurons. Knocking down TUBB3 inhibited Netrin-1 induced axon branching as well. These results suggest that DSCAM collaborates with DCC to regulate MT dynamics via direct binding to dynamic TUBB3 in Netrin-1-induced axon branching.

Molecular evolution and functional divergence of zebrafish (Danio rerio) cryptochrome genes

Cryptochromes function in animal circadian regulation. Zebrafish are known to have six cryptochrome (cry) genes but their evolutionary relationships are not yet fully resolved. Here, comparative genomic analyses revealed that a local duplication of ancestral chordate Cry occurred likely before the first round of vertebrate genome duplication (VGD); following two successive rounds of VGD and subsequent gene losses, coelacanths retained cry1a, cry1b, cry2 and cry3; and following the third-round teleost genome duplication (TGD) and subsequent gene losses, zebrafish retained six cry genes, renamed as cry1aa (zcry1a in the old nomenclature), cry1ab (zcry1b), cry1ba (zcry2a), cry1bb (zcry2b), cry2 (zcry3) and cry3 (zcry4). Molecular evolutionary analyses suggested that zebrafish cry genes have evolved divergent functions, which is further supported by their distinct and rhythmic expression patterns as shown by both in situ hybridization and quantitative real-time PCR. Systematic cell transfection assays divided six Cry proteins into repressive Cry1aa, Cry1ab, Cry1ba and Cry1bb, and non-repressive Cry2 and Cry3. Cry2 is non-repressive because it lacks an effective protein-protein interaction domain although it does possess a nuclear localization signal (NLS) motif, whilst Cry3 lacks both an NLS motif and a protein-protein interaction domain. These findings provide a better understanding of evolution of zebrafish cry genes.

siRNA targeting prohibitins inhibits proliferation and promotes apoptosis of gastric carcinoma cell line SGC7901 in vitro and in vivo

In the present study we investigate the effects of small interfering RNA (siRNA)-mediated silencing of prohibitins (Phbs) gene expressions on gastric carcinoma cell proliferation and apoptosis in vitro and in vivo. Firstly, Phbs proteins in five human gastric carcinoma cell lines were evaluated by Western blotting. Then three siRNA sequences targeting Phbs were designed and transfected into the cancer cell line with the highest Phbs protein expressions. The cell proliferation and apoptosis were analyzed by MTT and flow cytometry methods. In vivo, the effects of siRNAs on the proliferation and apoptosis were assayed in xenografted tumors of nude mice. Phbs proteins were expressed highest in gastric carcinoma cell line SGC7901. The cell proliferation significantly decreased upon Phbs silencing. The cell percentage in S phase was significantly lower in Phbs silenced groups, and the apoptotic cell ratio was significantly higher. siRNA targeting Phbs significantly inhibited the growth of the xenografted tumors. Further, Bcl-2 and Bax was respectively downregulated and upregulated after the Phbs silencing in the xenografted tumors. Caspase-3 and caspase-9 activities were significantly enhanced in the Phbs-silenced tumors. In summary, siRNA-mediated silencings of Phbs inhibit proliferation and promotes apoptosis of gastric carcinoma cells SGC7901 in vitro and in vivo, suggesting key roles of Phbs in the development of SGC7901 cell line.

RNAi-mediated silencing of ATP-binding cassette C4 protein inhibits cell growth in MGC80-3 gastric cancer cell lines

ATP-binding cassette C4/multidrug resistance associated protein 4 (ABCC4/MRP4) is a relatively well-studied member of the ATP-binding cassette drug transporter family. Recent studies suggested that ABCC4 is implicated in the development of several human cancers. In the present study, we report that knockdown of ABCC4 by lentivirus-delivered short hairpin RNA could inhibit gastric cancer cell growth in vitro. The proliferation of MGC80-3 cells was significantly reduced after infection with Lv-shABCC4, as determined by MTT and colony formation assays. In addition, knockdown of ABCC4 blocked the cell cycle progression in MGC80-3 cells. To our knowledge, it is the first report to investigate the role of ABCC4 in gastric tumorigenesis. Our data provides additional evidence that ABCC4/MRP4 could be a potential therapeutic target for gastric cancers.

Improvement of cerium on photosynthesis of maize seedlings under a combination of potassium deficiency and salt stress

Added Ce(3+) can partly substitute for Ca(2+) or Mg(2+) and improve photosynthesis under the deficiency of these elements, but very few studies focused on photosynthetic improvement in maize seedlings caused by K(+) deficiency, salt stress, especially a combination of K(+) deficiency and salt stress. In the present study, the effects of Ce(3+) on the photosynthesis of maize seedlings under the three different stresses were investigated. The results showed that added Ce(3+) under various stresses increased the ratios of free water/bound water and of K(+)/Na(+), the pigment contents, the values of Fv/Fm, Y(II), ETR(II), Y(NPQ), Qp, qL, NPQ, and qN of photosystem II (PSII), the values of Y(I) and ETR(I) of photosystem I (PSI) and the expression levels of LhcII cab1 and rbcL, and decreased the values of Y(NO) and Y(NA). This implied that added Ce(3+) depressed ion toxicity, photodamage of PSII, and acceptor side constraints of PSI, and enhanced adjustable energy dissipation, the responses of photochemistry, and carbon assimilation caused by K(+) deficiency, salt stress, and the combination of K(+) deficiency and salt stress. However, Ce(3+) mitigation of photosynthetic inhibition in maize seedlings caused by the combined stresses was greater than that of salt stress, and Ce(3+) mitigation under salt stress was greater than that under K(+) deficiency. In addition, the results also showed that Ce(3+) cannot improve photosynthesis and growth of maize seedlings under K(+) deficiency by substituting for K(+).

Self-reported menopausal symptoms in a racially diverse population and soy food consumption

OBJECTIVES

Evaluate the association of self-reported vasomotor symptom (VMS) frequency with race/ethnicity among a diverse midlife US population and explore menopause symptom differences by dietary soy isoflavone (genistein+daidzein) consumption.

STUDY DESIGN

Cross-sectional population-based study of peri- and postmenopausal women, ages 45-58.

OUTCOMES

Recent VMS frequency, VMS ever; recent symptom bother (hot flashes, night sweats, headache and joint-ache).

RESULTS

Of 18,500 potentially eligible women, 9325 returned questionnaires (50.4% response); 3691 were excluded (premenopausal, missing data, taking hormones). Of 5634 remaining women, 82.1% reported hot flashes ever, 73.1% reported night sweats ever; 48.8% and 38.6% reported recent hot flashes or night sweats, respectively. Compared with White women, Chinese, Japanese, Vietnamese, other Asian (each p<0.001) and Filipino (p<0.01) women less commonly reported ever having hot flashes; Asian women less commonly reported recent VMS bother (p<0.001). Black women more commonly reported hot flashes ever (p<0.05) and recent VMS bother (p<0.05). Compared with non-Hispanic White women, Hispanic women were less likely to report hot flashes (p<0.05) or night sweats (p<0.001) ever. Women were classified by isoflavone consumption: (1) none (n=1819), (2) 0.01-4.30 mg/day (n=1931), (3) 4.31-24.99 mg/day (n=1347) and (4) ≥ 25 mg/day (n=537). There were no group differences in recent VMS number/day: (1) 7.0 (95% CI 6.5, 7.5); (2) 6.4 (95% CI 6.0, 7.1); (3) 7.0 (95% CI 6.3, 8.2); and (4) 6.8 (95% CI 6.1, 7.7).

CONCLUSIONS

Menopausal symptoms, independent of isoflavone intake, varied considerably by race/ethnicity and were least common among Asian races.

miR-200b inhibits TGF-β1-induced epithelial-mesenchymal transition and promotes growth of intestinal epithelial cells

Inflammatory bowel disease (IBD), which consists of Crohn's disease (CD) and ulcerative colitis (UC), is a chronic, inflammatory disorder of the gastro-intestinal tract with unknown etiology. Current evidence suggests that intestinal epithelial cells (IECs) is prominently linked to the pathogenesis of IBD. Therefore, maintaining the intact of epithelium has potential roles in improving pathophysiology and clinical outcomes of IBD. MicroRNAs (miRNAs) act as post-transcriptional gene regulators and regulate many biological processes, including embryonal development, cell differentiation, apoptosis and proliferation. In this study, we found that miR-200b decreased significantly in inflamed mucosa of IBD, especially for UC, when compared with their adjacent normal tissue. Simultaneously, we also found that the genes of E-cadherin and cyclin D1 were reduced significantly and correlated positively to the miR-200b. In addition, the upregulation of transforming growth factor-beta 1 (TGF-β1) was inversely correlated to the miR-200b in IBD. To investigate the possible roles of miR-200b in IECs maintaining, we used TGF-β1 to induce epithelial-mesenchymal transition (EMT) in IEC-6 initially. After sustained over-expressing miR-200b in IEC-6, the EMT was inhibited significantly that was characterized by downregulation of vimentin and upregulation of E-cadherin. Furthermore, we found that miR-200b enhanced E-cadherin expression through targeting of ZEB1, which encode transcriptional repressors of E-cadherin. SMAD2 was found to act as a target of miR-200b with direct evidence that miR-200b binding to the 3′ UTR of SAMD2 and the ability of miR-200b to repress SMAD2 protein expression. With SMAD2 depletion, the expression of vimentin decreased correspondingly, which suggested miR-200b might reduce vimentin through regulating the SMAD2. With endogenous over-expression of miR-200b, the proliferation of IEC-6 cells increased significantly by increasing S-phase entry and promoting expression of the protein cyclin D1. Summarily, our study suggested a potential role for mir-200b in maintaining intact of intestinal epithelium through inhibiting EMT and promoting proliferation of IECs.

Magnesium deficiency results in damage of nitrogen and carbon cross-talk of maize and improvement by cerium addition

Magnesium (Mg) deficiency has been reported to affect plant photosynthesis and growth, and cerium (Ce) was considered to be able to improve plant growth. However, the mechanisms of Mg deficiency and Ce on plant growth remain poorly understood. The main aim of this work is to identify whether or not Mg deprivation affects the interdependent nitrogen and carbon assimilations in the maize leaves and whether or not Ce modulates the assimilations in the maize leaves under Mg deficiency. Maize plants were cultivated in Hoagland’s solution. They were subjected to Mg deficiency and to cerium chloride administration in the Mg-present Hoagland’s media and Mg-deficient Hoagland’s media.After 2 weeks,we measured chlorophyll (Chl) a fluorescence and the activities of nitrate reductase (NR), sucrose-phosphate synthase(SPS), and phosphoenolpyruvate carboxylase (PEPCase)in metabolic checkpoints coordinating primary nitrogen and carbon assimilations in the maize leaves. The results showed that Mg deficiency significantly inhibited plant growth and decreased the activities of NR, SPS, and PEPCase and the synthesis of Chl and protein. Mg deprivation in maize also significantly decreased the oxygen evolution, electron transport,and efficiency of photochemical energy conversion by photosystem II (PSII). However, Ce addition may promote nitrogen and carbon assimilations, increase PSII activities,and improve maize growth under Mg deficiency. Moreover,our findings would help promote usage of Mg or Ce fertilizers in maize production.

Long-lasting transcriptional refractoriness triggered by a single exposure to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrimidine

Parkinson's disease (PD) is a progressive neurodegenerative disorder whose etiology is thought to have environmental (toxin) and genetic contributions. The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrimidine (MPTP) induces pathological features of PD including loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and striatal dopamine (DA) depletion. We previously described the striatal transcriptional response following acute MPTP administration in MPTP-sensitive C57BL/6J mice. We identified three distinct phases: early (5h), intermediate (24h) and late (72h) and reported that the intermediate and late responses were absent in MPTP-resistant Swiss-Webster (SWR) mice. Here we show that C57BL/6J mice pre-treated with a single 40 mg/kg dose of MPTP and treated 9 days later with 4×20 mg/kg MPTP, display a striatal transcriptional response similar to that of MPTP-resistant SWR mice, i.e. a robust acute response but no intermediate or late response. Transcriptional refractoriness is dependent upon the dose of the priming challenge with as little as 10mg/kg MPTP being effective and can persist for more than 28 days. Priming of SWR mice has no effect on their response to subsequent challenge with MPTP. We also report that paraquat, another free radical producer, also elicits striatal transcriptional alterations but these are largely distinct from those triggered by MPTP. Paraquat-induced changes are also refractory to priming with paraquat. However neither paraquat nor MPTP elicits cross-attenuation. Thus exposure to specific toxins triggers distinct transcriptional responses in striatum that are influenced by prior exposure to the same toxin. The prolonged refractory period described here for MPTP could explain at the molecular level the reported discrepancies between different MPTP administration regimens and may have implications for our understanding of the relationship between environmental toxin exposure and PD.

Effects of manganese deficiency and added cerium on photochemical efficiency of maize chloroplasts

The mechanism of the fact that manganese deprivation and cerium addition affect the photochemical efficiency of plants is unclear. In this study, we investigated the improvement by cerium of the damage of the photochemical function of maize chloroplasts under manganese-deprived stress. Chlorophyll fluorescence induction measurements showed that the ratio of variable to maximum fluorescence (Fv/Fm) underwent great decreases under manganese deficiency, which was attributed to the reduction of intrinsic quantum efficiency of the photosystem II units. The electron flow between the two photosystems, activities of Mg(2+)-ATPase and Ca(2+)-ATPase, and rate of photophosphorylation on the thylakoid membrane of maize chloroplasts were reduced significantly by exposure to manganese deprivation. Furthermore, the inhibition of cyclic photophosphorylation was more severe than non-cyclic photophosphorylation under manganese deficiency. However, added cerium could relieve the inhibition of the photochemical reaction caused by manganese deprivation in maize chloroplasts. It implied that manganese deprivation could disturb photochemical reaction of chloroplasts strongly, which could be improved by cerium addition.

Basic fibroblast growth factor inhibits osteogenic differentiation of stem cells from human exfoliated deciduous teeth through ERK signaling

OBJECTIVE

Stem cells from human exfoliated deciduous teeth (SHED) are a unique postnatal stem cell population capable of regenerating mineralized tissue and treating immune disorders. However, the mechanism that controls SHED differentiation is not fully understood. Here, we showed that basic fibroblast growth factor (bFGF) treatment attenuated SHED-mediated mineralized tissue regeneration through activation of the extracellular signal-regulated kinase (ERK) 1/2 pathway.

MATERIAL AND METHOD

The level of mineralized nodule formation was assessed by alizarin red staining. Expression levels of osteogenic genes, osteocalcin and runt-related transcription factor 2, were examined by RT-PCR. Subcutaneous implantation approach was used to assess in vivo bone formation. Downstream signaling pathways of bFGF were examined by Western blotting.

RESULT

Activation of ERK1/2 signaling by bFGF treatment inhibited WNT/β-catenin pathway, leading to osteogenic deficiency of SHED. ERK1/2 inhibitor treatment rescued bFGF-induced osteogenic differentiation deficiency.

CONCLUSION

These data suggest that bFGF inhibits osteogenic differentiation of SHED via ERK1/2 pathway. Blockade ERK1/2 signaling by small molecular inhibitor treatment improves bone formation of SHED after bFGF treatment.

Effects of manganese deficiency and added cerium on nitrogen metabolism of maize

Manganese is one of the essential microelements for plant growth, and cerium is a beneficial element for plant growth. However, whether manganese deficiency affects nitrogen metabolism of plants and cerium improves the nitrogen metabolism of plants by exposure to manganese-deficient media are still unclear. The main aim of the study was to determine the effects of manganese deficiency in nitrogen metabolism and the roles of cerium in the improvement of manganese-deficient effects in maize seedlings. Maize seedlings were cultivated in manganese present Meider's nutrient solution. They were subjected to manganese deficiency and to cerium chloride administered in the manganese-present and manganese-deficient media. Maize seedlings grown in the various media were measured for key enzyme activities involved in nitrogen metabolism, such as nitrate reductase, glutamate dehydrogenase, glutamine synthetase, and glutamic-oxaloace transaminase. We found that manganese deficiency restricted uptake and transport of NO(3)(-), inhibited activities of nitrogen-metabolism-related enzymes, such as nitrate reductase, glutamine synthetase, and glutamic-oxaloace transaminase, thus decreasing the synthesis of chlorophyll and soluble protein, and inhibited the growth of maize seedlings. Manganese deficiency promoted the activity of glutamate dehydrogenase and reduced the toxicity of excess ammonia to the plant, while added cerium relieved the damage to nitrogen metabolism caused by manganese deficiency in maize seedlings. However, cerium addition exerted positively to relieve the damage of nitrogen metabolism process in maize seedlings caused by exposure to manganese-deficient media.

Inhibition of nitrogen and photosynthetic carbon assimilation of maize seedlings by exposure to a combination of salt stress and potassium-deficient stress

The main aim of this work is to identify how the combined stresses affect the interdependent nitrogen and photosynthetic carbon assimilations in maize. Maize plants were cultivated in Meider's solution. They were subjected to salt stress and potassium deficiency in the K-present Meider's media and K-deficient Meider's media. After 5 weeks, we measured chlorophyll a fluorescence and the activities of several enzymes in metabolic checkpoints coordinating primary nitrogen and carbon assimilation in the leaves of maize. The study showed that the combination of salt stress and potassium-deficient stress more significantly decreased nitrate uptake, plant growth, the activities of nitrate reductase, glutamate dehydrogenase, glutamate synthase, urease, glutamic-pyruvic transaminase, glutamic-oxaloace transaminase, sucrose-phosphate synthase, phosphoenolpyruvate carboxylase, and the synthesis of free amino acids, chlorophyll, and protein than those of each individual stress, respectively. However, the combined stresses significantly increased the accumulation of ammonium and carbohydrate products. The combined stresses also significantly decreased the oxygen evolution, the electron transport, and the efficiency of photochemical energy conversion by photosystem II in maize seedlings. Taken together, a combination of salt stress and potassium-deficient stress impaired the assimilations of both nitrogen and carbon and decreased the photosystem II activity in maize.