[HVPG minimally invasive era: exploration based on forearm venous approach]

Objective: The transjugular or transfemoral approach is used as a common method for hepatic venous pressure gradient (HVPG) measurement in current practice. This study aims to confirm the safety and effectiveness of measuring HVPG via the forearm venous approach. Methods: Prospective recruitment was conducted for patients with cirrhosis who underwent HVPG measurement via the forearm venous approach at six hospitals in China and Japan from September 2020 to December 2020. Patients' clinical baseline information and HVPG measurement data were collected. The right median cubital vein or basilic vein approach for all enrolled patients was selected. The HVPG standard process was used to measure pressure. Research data were analyzed using SPSS 22.0 statistical software. Quantitative data were used to represent medians (interquartile ranges), while qualitative data were used to represent frequency and rates. The correlation between two sets of data was analyzed using Pearson correlation analysis. Results: A total of 43 cases were enrolled in this study. Of these, 41 (95.3%) successfully underwent HVPG measurement via the forearm venous approach. None of the patients had any serious complications. The median operation time for HVPG detection via forearm vein was 18.0 minutes (12.3~38.8 minutes). This study confirmed that HVPG was positively closely related to Child-Pugh score (r = 0.47, P = 0.002), albumin-bilirubin score (r = 0.37, P = 0.001), Lok index (r = 0.36, P = 0.02), liver stiffness (r = 0.58, P = 0.01), and spleen stiffness (r = 0.77, P = 0.01), while negatively correlated with albumin (r = -0.42, P = 0.006). Conclusion: The results of this multi-centre retrospective study suggest that HVPG measurement via the forearm venous approach is safe and feasible.

[Effects of deficit irrigation on seed production performance and water use efficiency of two native plant species in arid areas]

Scientific irrigation is of great significance to plant seed production. With two excellent native plant species in desert steppe, Agropyron mongolicum and Lespedeza potaninii, as the objects, and full irrigation as the control, we explored the effects of deficit irrigation in different growth stages on the seed production and water use efficiency (WUE) of those two species. The results showed that, compared with the control, soil water content of both species decreased under deficit irrigation. The decrease of soil water content of A. mongolicum mainly occurred in the 0-60 cm soil layer, while there was no obvious stratification for the reduction of soil water content of L. potaninii. There were significant differences in the yield components of A. mongolica under deficit irrigation. The seed yield of deficit irrigation at the flowering stage was the highest. There were significant differences in the numbers of fertile tillers, florets and pods of L. potaninii among treatments, but no significant difference in seed yield. There were positive correlations between seed yield of A. mongolicum and the numbers of fertile tillers (r=0.776) and spikelets (r=0.717). The racemes of L. potaninii was significantly negatively correlated with the number of fertile tillers (r=-0.685), and positively correlated with the number of florets (r=0.412). Compared with full irrigation, water consumption of seed production of the two native plant species was reduced under deficit irrigation, but water use efficiency was improved, with the strongest improvement at the flowering stage of A. mongolicum (32.9%) and at the branching stage of L. potaninii (27.4%). Therefore, proper deficit irrigation could improve water use efficiency of both plant species. From the perspective of water use efficiency and seed yield, deficit irrigation could be used for artificial breeding of A. mongolicum and L. potaninii seeds in arid area, with the suitable growth stage for deficit being the flowering and the branching stages, respectively.

[Percutaneous biliary stent combined with brachytherapy for malignant obstructive jaundice: a multicenter retrospective controlled study]

Objective: To investigate the efficacy, safety and prognostic factors of percutaneous biliary stent combined with iodine-125 seed chain brachytherapy (radiotherapy) in the treatment of malignant obstructive jaundice. Methods: Data of 107 cases with malignant obstructive jaundice treated with percutaneous biliary stent implantation from January 2017 to December 2020 were retrospectively analyzed. Among them, 58 cases received biliary stent combined with iodne-125 seed chain brachytherapy (study group), and 49 cases received biliary stent implantation (control group). The changes of bilirubin, stent patency time, complications, overall survival (OS) and prognostic factors were analyzed in both groups. Results: The incidence of complications in the study group and the control group were 17.2% and 18.3% respectively, and the difference was not statistically significant (P=0.974). Serum total bilirubin levels were decreased significantly in both groups at one month after surgery (P<0.001). Postoperative stent patency time was significantly better in the study group (10.0±1.6 months) (95% CI: 8.2～12.5) than that in the control group (5.2±0.4 months) (95% CI: 4.1～6.0, P<0.001). The median OS was longer in the study group (11.2±1.8 months) (95% CI: 9.2～12.8) than that in the control group (8.0±1.1 months) (95% CI: 8.0～12.8, P<0.001). Multivariate analysis result showed that stent combined with brachytherapy (HR=0.08, 95% CI:0.04～0.15, P<0.001) and receiving further anti-tumor therapy after surgery (HR=0.27, 95% CI:0.15~0.49, P<0.001) were independent risk factors affecting the patency of biliary stents. Preoperative percutaneous transhepatic biliary drainage (HR=0.46, 95%CI:0.28～0.74, P=0.002), stent combined with brachytherapy (HR=0.23, 95%CI:0.14～0.39, P<0.001) and receiving further anti-tumor therapy after surgery (HR=0.37, 95%CI:0.22～0.61, P<0.001) were independent risk factors affecting OS. Conclusion: Percutaneous biliary stent combined with brachytherapy is safe and effective in the treatment of malignant obstructive jaundice, which can significantly prolong the patency time of biliary stent and the survival time of patients.

[Interpretation of the American Association for Thoracic Surgery expert consensus document: coronary artery bypass grafting in patients with ischemic cardiomyopathy and heart failure in 2021]

An expert consensus on coronary artery bypass grafting (CABG) in patients with ischemic cardiomyopathy (ICM) was released by the American Association for Thoracic Surgery in May 2021, which contains a vast array of perioperative recommendations. During preoperative period, a comprehensive assessment on ICM including myocardial viability and valve function by a multi-disciplinary team (MDT) approach should be performed. In terms of intraoperative period, multiple arterial conduits and on-pump CABG using cold blood cardioplegia should be considered, meanwhile, other aspects involving concomitant management of mitral valve regurgitation and arrythmia, as well as active use of mechanical cardiac assist devices (e.g., intra-aortic balloon pump) should also be achieved. Finally, a range of postoperative interventions which includes standardized MDT management in intensive care unit (ICU), continuous use of cardiac assist devices, cardiac pacing, close follow-up within 90 days and drug treatment strictly guided by the guidelines after discharge from hospital should be conducted. The above-mentioned perioperative bundled care might reduce perioperative complications and operative mortality, and thus improve the prognosis of the patients with ICM.

[Current status and controversy of neoadjuvant therapy in pancreatic cancer]

Pancreatic cancer is considered to be the most malignant digestive tract tumor due to its high invasiveness, metastasis and recurrence rate. In recent years, neoadjuvant therapy has brought new insights to the treatment of pancreatic cancer. To date, the value of neoadjuvant therapy in pancreatic cancer has been widely recognized, but there is a lack of specific regimens. The superiority and inferiority of various regimens are still uncertain, therefore, the efficacy of neoadjuvant therapy can be evaluated combined with imaging, functional and biological markers.

Relationship between polyamines conjugated to mitochondrion membrane and mitochondrion conformation from developing wheat embryos under drought stress

The mitochondrion conformation and the contents of conjugated polyamines were investigated using the embryos of developing wheat (Triticum aestivum L.) grains of two cultivars differing in drought tolerance as experiment materials. After drought stress treatment for 7 days, the relative water content of embryo and relative increase rate of embryo dry weight of the drought-sensitive Yangmai No. 9 cv. decreased more significantly than those of the drought-tolerant Yumai No. 18 cv. Furthermore, the changes in mitochondrion conformation of Yangmai No. 9 were more marked. Meanwhile, the increases of the contents of conjugated non-covalently spermidine (CNC-Spd) and conjugated covalently putrescine (CC-Put) of Yumai No. 18 were more obvious than those of Yangmai No. 9. Treatment with exogenous Spd not only alleviated the injury of drought stress to Yangmai No. 9, but also enhanced the increase of CNC-Spd content and inhibited the change in the mitochondrion conformation of this cultivar. The treatments of Yumai No. 18 with two inhibitors, methylglyoxyl-bis (guanylhydrazone) and phenanthrolin, significantly inhibited the drought stress-induced increases of CNC-Spd and CC-Put contents of the cultivar, respectively. Meanwhile, the treatments with the two inhibitors aggravated the injury of drought stress to Yumai No. 18 and enhanced the change in the mitochondrion conformation of this cultivar. These results mentioned above suggested that the CNC-Spd and CC-Put in embryo mitochondrion membrane isolated from developing grains could enhance the wheat tolerance to drought stress by maintaining the mitochondrion conformation.

[Etiological analysis of hepatopathy of unknown etiology in 470 cases undergoing routine liver biopsy examination]

Objective: To understand the etiology of hepatopathy of unknown etiology in patients undergoing liver biopsy. Methods: Demographic data and pathological examination reports of patients with hepatopathy of unknown etiology who underwent liver biopsy examination at outpatient and inpatient of the Second Hospital of Nanjing between January 2017 and June 2018 were retrospectively collected. All liver histopathological sections combined with clinical and pathological features based on liver biopsy examinations were diagnosed by a reputed clinician and a pathologist. Results: A total of 470 cases with hepatopathy of unknown etiology who underwent liver biopsy were enrolled. Of these, 425 cases (90.4%) had a definite diagnosed disease after comprehensive analysis of pathological and clinical data. The diagnosis of hepatopathy of unknown etiology included 11 diseases: 90 cases with autoimmune hepatitis had autoimmune liver disease (19.1%), 38 cases had primary biliary cholangitis (8.1%), 43 cases with overlap syndrome of autoimmune hepatitis had primary biliary cholangitis (9.1%), 118 cases had drug-induced liver injury (25.1%), 75 cases had nonalcoholic fatty liver disease (NAFLD) (16.0%), 12 cases had alcoholic liver disease (2.6 cases) %), 15 cases (3.2%) had vascular liver disease, 7 cases (1.5%) had hereditary metabolic liver disease, 5 cases (1.1%) had other systemic diseases, 16 cases (3.4%) had more than two kinds of liver diseases, and 6 cases (1.3%) had others rare liver diseases. Conclusion: Over 90% cause of the hepatopathy of unknown etiology in the long run can be determined, and the main causes are autoimmune liver disease, drug-induced liver injury, and nonalcoholic fatty liver disease, which needs multidisciplinary cooperation to diagnose, and clinicians need to master the basic and clinical knowledge of liver diseases as well as liver pathology, hepatobiliary imaging, and genetics.

PD-1 blockade in neoadjuvant setting of DNA mismatch repair-deficient/microsatellite instability-high colorectal cancer

Background: Although PD-1 blockade has significantly improved the survival of metastatic colorectal cancer with DNA Mismatch Repair-Deficient/Microsatellite Instability-High (MSI-H), the data on neoadjuvant setting is limited.

Methods: In this retrospective study, we enrolled eight patients with advanced MSI-H colorectal cancer from three hospitals. Four patients are locally advanced and four are metastatic. All the patients received at least two doses of PD-1 antibody with or without chemotherapy as neoadjuvant therapy. The aim of the present study was to evaluate the short-term efficacy and toxicities of this strategy.

Results: All the enrolled eight patients had a major response in imaging and/or pathological evaluation. Five of the seven resected patients were evaluated as pathological complete response. One patient without surgery has a clinical complete response (cCR) tumor response.

Conclusions: Neoadjuvant PD-1 blockade induced tumor regression with a major clinical and pathological response in advanced dMMR/MSI-H colorectal cancer. Further studies are required to evaluate the long-term effect of this strategy.

[Mid-term outcomes of coronary artery bypass surgery with left radial artery bypassed to right main coronary artery of severe stenosis]

Objective: To evaluate the mid-term outcomes of coronary artery bypass grafting (CABG) with left radial artery (RA) graft bypassed to right main coronary artery (RCA) of severe stenosis. Methods: Between September 2014 and April 2019, a total of consecutive 47 patients who had severe stenosis (≥90%) of RCA underwent total arterial revascularization, with left RA bypassed to RCA. There were 31 males and 16 females, with a mean age of (56.5±9.7) years old. The perioperative outcomes were observed and mid-term results were followed up. Results: A total of 46 left internal mammary artery (LIMA) grafts, 47 left radial artery (LRA), and 40 right RA grafts (RRA) were harvested with pedicles. LIMA was bypassed to LAD in 43 patients, RRA was to diagonal branches, ramus or oblique marginal in 37 cases, and LRA was to RCA. All grafts (except 3 composite Y or T grafts) were single. Mean graft number was 2-4 (2.7±0.9). There was one death due to cardiac tamponade. Three patients had postoperative atrial fibrillation, 1 had a forearm hematoma, 1 had acute renal insufficiency, and 2 had acute myocardial infarction. The mean tracheal intubation duration was 3.5-20.3 (8.3±4.7) hours, and the mean hospital stay was 6-13 (7.1±2.9) days. The average follow-up was 3-47 (23.3±7.5) months, with a follow-up rate of 86.96% (40/46). There were no major cardiovascular events during the follow-up. Three month after surgery, the mean left ventricular ejection fraction was significantly improved than that of pre-operation (60.0%±4.0% vs 42.4%±7.5%, P=0.003). Computed tomography angiography (CTA) examination showed that 58.7% (27/46) of patients had patent LRA after a mean follow-up duration of (19.5±7.3) months. Conclusion: CABG with LRA bypassed to RCA of severe stenosis proves to be safe and effective, with good mid-term outcomes.

[The effects of wireless audio microphones on sentences recognition threshold for hearing aid users in noise]

Objective:This study was aimed to observe the effects of wireless audio microphone on hearing aids effect in noise at different listening distances. Method:Twenty-three subjects with bilateral sensorineural hearing loss, including 17 males and 6 females were fitted with binaural hearing aids. These patients did sentences recognition tests at two different listening distance（1.5 and 3 meters） in noise. The subjects were tested under three conditions, ①with hearing aids alone; ②with the wireless audio microphone alone; ③with hearing aid microphone and mini audio microphone simultaneously. Result:The sentence recognition threshold at 3 meters listening distance is significantly higher than it at 1.5 meters listening distance with hearing aids alone（P<0.05）. There is no significant difference in the sentence recognition threshold between two listening distances when the wireless audio microphone was switched on（P>0.05）. Conclusion:Mini audio microphone can significantly improve hearing aids effect in long distance listening in noise.

[Study on spectrum of UGT1A1 mutations in connection with inherited non-hemolytic unconjugated hyperbilirubinemia]

Objective: To compare and analyze patient's general condition, changes in laboratory parameters, and the spectrum of UGT1A1 mutations in patients with inherited non-hemolytic unconjugated hyperbilirubinemia. Methods: A retrospective study was conducted at Nanjing Second Hospital from January 2015 to July 2018 and patients' demographic characteristics, liver function test, and UGT1A1 gene were analyzed. The categorical variable data were compared by χ (2) test. The normal distribution continuous variable data were compared by t-test and the non-normal distribution continuous variable data were compared using Mann-Whitney U test. Results: Of the 51 patients with inherited non-hemolytic unconjugated hyperbilirubinemia, 44 (86.3%) were Gilbert's syndrome (GS) and seven (13.7%) were Crigler-Najjar syndrome type II (CNS- II). The male to female ratio was 2.9:1 and the average age was 36.11 ± 13.17 years. Six variant types were detected: C. -40_-39insTA, C. -3279T > G, c.211G > A (p.G71R), c.686C > A (p.P229Q), c.1091C > T (p.P364L), c.1456T > G (P.Y486D). Among them, c.211G > A accounted for 58.82% (30/51), c.-40_-39insTA accounted for 27.5% (14/51), and c.1456T > G accounted for 25.5% (13/51). The total bilirubin(TB) and unconjugated bilirubin (UCB) in CNS-II patients were significantly higher than GS patients[155.91 (130 ~ 207) vs. 38.25(29 ~ 52.15) μmol/L, U = 0, P < 0.01; 144.13 (120.8 ~ 197) vs. 30.00 (21.7 ~ 46.75) μmol/L, U = 0.00, P < 0.01, respectively]. Exon mutations of c.1091C > T and c.1456T > G were statistically significant(P < 0.01).There were no differences in age, TB, UCB, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) between the c.211G > A homozygous variants and heterozygous variants (P > 0.05). Conclusion: The common pathogenic mutations of UGT1A1 gene were c.211G > A, c.-40_-39insTA, c.1456T > G. c.211G > A. The mutation has little effect on the level of total bilirubin, but c.1091C > T, c.1456T > G mutations has great influence on the level of total bilirubin.

Relationship between sleep disorders and lymphocyte subsets and cytokines in patients with lung cancer

This study aimed to investigate the relationship between sleep disorders and lymphocyte subsets and cytokines in patients with lung cancer undergoing radiotherapy, and to establish a theoretical foundation for predicting sleep disorders and preventing interventions in radiotherapy in lung cancer patients. Ninety-two patients with lung cancer requiring radiotherapy were selected as the study subjects. The patients' demographic data and disease-related conditions were investigated. Their quality of sleep was measured before radiotherapy, after two and four weeks of radiotherapy, and at the end of radiotherapy. According to the Pittsburgh Sleep Quality Index Number Table (PSQI), patients with PSQI score> 7 points were put into a sleep disorder group, and patients with PSQI score 0-7 were put into a normal sleep group. Lymphocyte subsets were enumerated and cytokine levels (IL-6, IL-1b) were measured during these four periods. The difference in sleep disorders at four weeks between patients with or without synchronous chemotherapy was statistically significant (P less than 0.05). The levels of lymphocyte subsets in the sleep disorder group and the control sleep group showed no difference in the index of lymphocyte subsets before radiotherapy. In the sleep disorder group, CD4+ cells were lower after two weeks of radiotherapy (P less than 0.05). After four weeks of radiotherapy, CD3+, CD4+, and CD16+56+ subsets were lower (P less than 0.05). At the end of radiotherapy, there was no difference in each index. There was no significant difference in IL-6 levels between the two groups before radiotherapy, after two weeks, or after four weeks (P greater than 0.05). At the end of radiotherapy, IL-6 levels in the sleep disorder group were higher than those in the control sleep group (P less than 0.05). There was no significant difference in IL-1b between the two groups (P greater than 0.05). In conclusion, monitoring of T-lymphocyte subsets and IL-6 levels in patients is enhanced during radiotherapy. Clinically effective programs of radiotherapy for lung cancer improve the body's immune status.

Experimental Evidence of Kinetic Effects in Indirect-Drive Inertial Confinement Fusion Hohlraums

We present the first experimental evidence supported by simulations of kinetic effects launched in the interpenetration layer between the laser-driven hohlraum plasma bubbles and the corona plasma of the compressed pellet at the Shenguang-III prototype laser facility. Solid plastic capsules were coated with carbon-deuterium layers; as the implosion neutron yield is quenched, DD fusion yield from the corona plasma provides a direct measure of the kinetic effects inside the hohlraum. An anomalous large energy spread of the DD neutron signal (∼282  keV) and anomalous scaling of the neutron yield with the thickness of the carbon-deuterium layers cannot be explained by the hydrodynamic mechanisms. Instead, these results can be attributed to kinetic shocks that arise in the hohlraum-wall-ablator interpenetration region, which result in efficient acceleration of the deuterons (∼28.8  J, 0.45% of the total input laser energy). These studies provide novel insight into the interactions and dynamics of a vacuum hohlraum and near-vacuum hohlraum.

Safety and effect on ablation size of hydrochloric acid-perfused radiofrequency ablation in animal livers

PURPOSE

Our objective was to determine the safety and ablation size of hydrochloric acid-perfused radiofrequency ablation (HCl-RFA) in liver tissues, prospectively using in vivo rabbit and ex vivo porcine liver models.

MATERIALS AND METHODS

The livers in 30 rabbits were treated in vivo with perfusions of normal saline (controls) and HCl concentrations of 5%, 10%, 15%, and 20%, during RFA at 103 °C and 30 W for 3 min. For each experimental setting, six ablations were created. Safety was assessed by comparing baseline weight and selected laboratory values with those at 2, 7, and 14 days' post-ablation, and by histopathological analysis. The livers in 25 pigs were treated ex vivo with the same five perfusions during RFA at 103 °C, at both 30 W and 60 W, for 30 min. Ablation diameters and volumes were measured by two examiners.

RESULTS

Rabbit weights and selected laboratory values did not differ significantly from baseline to 7 and 14 days' post-ablation, liver tissues outside the ablation zones were normal histologically, and adjacent organs showed no macroscopic damage. The mean ablation volumes in the porcine livers treated with HCl-RFA were all larger than those treated with normal saline perfusion during RFA (NS-RFA), at both 30 W and 60 W (p < 0.001). The largest ablation volume and transverse diameter were observed in the porcine livers during 10% HCl-RFA at 60 W, measuring 179.22 (SD = 24.79) cm³ and 6.84 (SD = 0.36) cm, respectively.

CONCLUSIONS

Based on our experiments, HCl-RFA in the liver appears to be as safe as NS-RFA while also resulting in larger ablation zones.

[Determination of Methcathinone in Urine by GC-MS]

OBJECTIVES

To establish a method for the analysis of methcathinone in urine by gas chromatography-mass spectrometry （GC-MS）.

METHODS

Proadifen hydrochloride （internal standard） and buffer solution （pH=9） were added into the urine samples, and methcathinone was extracted by ethyl acetate. The extract was volatilized in 50 ℃ nitrogen gas flow and the remnant was dissolved by methanol and analysed by GC-MS.

RESULTS

The methcathinone in urine showed a good linear relationship in the mass concentration range of 0.02-2.00 μg/mL. The linear equation was y=0.301 9 x+0.018 9 （r=0.999 2）, and the detection limit was 0.01 μg/mL. The recoveries of methcathinone in urine was 96.4%-99.2%, with the intra-day precision of 5.8%-7.6% and the inter-day precision of 6.0%-8.1%.

CONCLUSIONS

The method is convenient and sensitive, which can be applied to the forensic identification of methcathinone in urine.

[Age dependent changes in mandarin speech perception in normal hearing people]

Objective:To investigate if and when the mandarin speech perception ability deteriorates with age in adults with audiometrically normal hearing sensitivity.Method:The participant group included 75 normal hearing adults sampled from across the entire range of adulthood, of which there are 20 males and 55 femals. The participants were divided into 5 groups with 15 participants per age group: 20-30 years, 31-40 years, 41-50 years, 51-60 years, and 61-70 years. We applied speech perception test using Mandarin Hearing in Noise Test.Result:The speech perception scores were significantly different among the five groups in 0 dB and -5 dB conditions (P<0.001), but they weren't significantly different among the five groups in quiet, 10 dB and 5 dB (P>0.005).There was a significant negative correlation between speech perception and age in -5 dB conditions.Conclusion:When the background noise becomes more severe even for participants with audiomerically normal hearing, it was shown that speech perception declined with age.

[The multicenter study on the registration and follow-up of low anticoagulation therapy for the heart valve operation in China]

OBJECTIVE

To investigate the optimal anticoagulation methods and monitoring strategy for Chinese patients undergoing heart valve replacement, which is potentially quite different from western populations.

METHODS

In this multicenter prospective cohort study, the anticoagulation and monitoring strategy data was acquired from 25 773 in-hospital patients in 35 medical centers and 20 519 patients in outpatient clinic in 11 medical centers from January 1st, 2011 to December 31th, 2015.

RESULTS

As for in-hospital patients, mean age of study population was (48.6±11.2) years old; main etiology of valve pathology was rheumatic (87.5%) origin among study cohort; 94.8% of study population received mechanical valve implantation; international normalized ratio (INR) monitoring (in all the study centers) and low-intensity anticoagulation strategy (31 hospitals chose target INR range of 1.5-2.5, and actual values of INR among 89.2% of 100 069 in-hospital monitoring samples were 1.5-2.5), with mean actual INR values of 1.84±0.53, and warfarin dosage of (2.82±0.93) mg/d were widely adopted among the study centers; strategies of in-hospital warfarin administration were similar in all the study centers; complication rates of low-intensity anticoagulation strategy were low in severe hemorrhage (0.02%), thrombosis (0.05%), and thromboembolism (0.05%) events, without anticoagulation-related death.As for 18 974 outpatient clinic patients, the follow-up rate was 92.47%, with a total of 30 012 patient-years (Pty). Anticoagulation-related morbidity and mortality rates were 0.67% and 0.15% Pty; major hemorrhage morbidity and mortality rates were 0.25% and 0.13% Pty; thromboembolism morbidity and mortality rates were 0.45% and 0.03% Pty.The mean dosage of warfarin daily dosage was (2.85±1.23) mg/d and INR value was 1.82±0.57.No significant regional difference in the intensity of anticoagulation therapy was noted during the study.

CONCLUSIONS

INR can be used as a normalized indicator for intensity of anticoagulation therapy in China.The optimal anticoagulation intensity with INR range from 1.5 to 2.5 is safe and effective for Chinese patients with heart valve replacement, and there is no significant regional difference in the intensity of anticoagulation therapy.

The antitumor efficacy of anti-p21Ras scFv mediated by the dual-promoter-regulated recombinant adenovirus KGHV300

Ras mutations and overexpression of the Ras protein, p21Ras, are main causes of cancer development and progression, which has made the Ras gene and p21Ras important targets for therapy of Ras-driven cancers. We previously prepared recombinant adenovirus KGHV100 based on replication-defective adenovirus type 5, which could intracellularly express anti-p21Ras single chain fragment viable antibodies (scFv) and repress tumor growth in vitro and in vivo. However, the anti-tumor effects of this anti-p21Ras scFv were limited by short-term scFv expression due to a replication defect of KGHV100. To enhance the anti-tumor efficacy and safety of anti-p21Ras scFv, the present study constructed a dual-promoter-regulated recombinant adenovirus KGHV300 that carried anti-p21Ras scFv. In KGHV300, the expression levels of the essential replication genes E1a and E1b, were controlled by the human telomerase reverse transcriptase promoter and the hypoxia response element, respectively, and the anti-p21Ras scFv gene was controlled by the cytomegalovirus promoter. The conditional replication of KGHV300 and its antitumor efficacy were characterized in several tumor cell lines in vitro and in xenograft models of human breast cancer in nude mice. TCID50 assay demonstrated that KGHV300 could replicate in tumor cell lines but not in normal cell lines. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay indicated that the growth of tumor cells was effectively inhibited by KGHV300 infection. In MDA-MB-231 tumor xenograft models, KGHV300 effectively and significantly inhibited tumor growth and induced apoptosis of tumor cells. We concluded that the recombinant adenovirus KGHV300 may be a more potent and safer antitumor therapeutic for Ras-driven cancer biotherapy.

miR-96 inhibits cardiac hypertrophy by targeting growth factor receptor-bound 2

Increasing evidence has indicated that microRNAs are involved in the pathogenesis of cardiac hypertrophy. However, whether miR-96 is involved in heart diseases, particularly cardiac hypertrophy, remains unclear. In this study, we found that miR-96 is a negative regulator of cardiac hypertrophy. In primary cardiomyocytes, overexpression of miR-96 inhibited phenylephrine-induced cardiomyocyte hypertrophy and decreased the mRNA expression of cardiac hypertrophy markers such as atrial natriuretic factor and β-myosin heavy chain. Interestingly, we found that growth factor receptor-bound 2 is a direct target of miR-96, which is a negative regulator of cardiac hypertrophy. Overexpression of miR-96 in cardiomyocytes led to reduced growth factor receptor-bound 2 expression. More importantly, miR-96 repressed the extracellular-regulated protein kinase signaling pathway by targeting growth factor receptor-bound 2 in cardiomyocytes. Our data demonstrate that miR-96 is a negative regulator of cardiac hypertrophy and extracellular-regulated protein kinase signaling, thus offering a new therapeutic strategy for cardiac hypertrophy.

Optimizing the electrical excitation of an atmospheric pressure plasma advanced oxidation process

The impact of pulse-modulated generation of atmospheric pressure plasma on the efficiency of organic dye degradation has been investigated. Aqueous samples of methyl orange were exposed to low temperature air plasma and the degradation efficiency was determined by absorbance spectroscopy. The plasma was driven at a constant frequency of 35kHz with a duty cycle of 25%, 50%, 75% and 100%. Relative concentrations of dissolved nitrogen oxides, pH, conductivity and the time evolution of gas phase ozone were measured to identify key parameters responsible for the changes observed in degradation efficiency. The results indicate that pulse modulation significantly improved dye degradation efficiency, with a plasma pulsed at 25% duty showing a two-fold enhancement. Additionally, pulse modulation led to a reduction in the amount of nitrate contamination added to the solution by the plasma. The results clearly demonstrate that optimization of the electrical excitation of the plasma can enhance both degradation efficiency and the final water quality.

Identification of two ATR-dependent phosphorylation sites on coronavirus nucleocapsid protein with nonessential functions in viral replication and infectivity in cultured cells

Coronavirus encodes an extensively phosphorylated and highly basic nucleocapsid (N) protein. Previous studies have identified Ser190, Ser192, Thr378 and Ser379 as the phosphorylation sites for coronavirus infectious bronchitis virus (IBV) N protein. In this study, we show that phosphorylation at Thr378 and Ser379 sites is dependent on the ataxia-telangiectasia mutated (ATM) and Rad3-related (ATR), a kinase activated during IBV replication. Introduction of Ala substitutions at these two sites individually, in combination of the two and together with other two sites (Ser190 and Ser192) into an infectious IBV clone did not affect recovery of the recombinant viruses containing the mutations. A mutant virus (rIBV-Nm4) carrying the four Ala substitutions grew at a similar, if not better, growth rate as wild type virus. This study reveals a cellular kinase responsible for phosphorylation of a coronavirus N protein at two positions and the functional consequence of this modification on coronavirus replication.

•

We study the functional relevance of phosphorylation of IBV N on viral replication.

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We identify two ATR-dependent phosphorylation sites on IBV N protein.

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We analyze the functions of these sites on IBV replication and infectivity.

Metabolic changes of human dental pulp after rapid palatal expansion

OBJECTIVES

To investigate rapid palatal expansion (RPE)-induced metabolic changes in human dental pulp by measuring the expression and activity of aspartate aminotransferase (AST).

METHODS

mRNA and protein levels of AST in human dental pulp were measured by quantitative real-time polymerase chain reaction and Western blot, respectively. Furthermore, the activity of AST was measured by a full automatic biochemical analyzer.

RESULTS

AST mRNA and protein levels were found to be expressed in normal dental pulp. Moreover, the expression of AST was increased significantly after 14 days of RPE and then decreased at 1 month in retention. Three and 6 months after RPE, the AST expression level was gradually decreased to its baseline level. Similarly, AST activity was significantly elevated after 14 days of RPE, which was then down-regulated at 1 month in retention but was still kept at a higher level as compared with the control group. The enzymatic activity of AST was slowly decreased to its baseline level at 3 and 6 months in retention.

CONCLUSIONS

These results showed that significant reversible metabolic changes occurred in dental pulp during RPE, which revealed the high capacity of the pulp tissue for adaptation to this orthopedic method.

Artemin is oncogenic for human mammary carcinoma cells

We report that artemin, a member of the glial cell line-derived neurotrophic factor family of ligands, is oncogenic for human mammary carcinoma. Artemin is expressed in numerous human mammary carcinoma cell lines. Forced expression of artemin in mammary carcinoma cells results in increased anchorage-independent growth, increased colony formation in soft agar and in three-dimensional Matrigel, and also promotes a scattered cell phenotype with enhanced migration and invasion. Moreover, forced expression of artemin increases tumor size in xenograft models and leads to highly proliferative, poorly differentiated and invasive tumors. Expression data in Oncomine indicate that high artemin expression is significantly associated with residual disease after chemotherapy, metastasis, relapse and death. Artemin protein is detectable in 65% of mammary carcinoma and its expression correlates to decreased overall survival in the cohort of patients. Depletion of endogenous artemin with small interfering RNA, or antibody inhibition of artemin, decreases the oncogenicity and invasiveness of mammary carcinoma cells. Artemin is therefore oncogenic for human mammary carcinoma, and targeted therapeutic approaches to inhibit artemin function in mammary carcinoma warrant consideration.

Coronavirus envelope protein: a small membrane protein with multiple functions

Coronavirus envelope protein is a small membrane protein and minor component of the virus particles. It plays important roles in virion assembly and morphogenesis, alteration of the membrane permeability of host cells and virus-host cell interaction. Here we review recent progress in characterization of the biochemical properties, membrane topology and functions of the protein.

Transcriptional activation of p53 by Pitx1

Little is known about factors that stimulate transcription of the p53 tumor suppressor gene. Here, we report that the human pituitary homeobox 1 (hPitx1) transcription factor increases the expression of p53 at the mRNA and protein levels in human mammary carcinoma (MCF-7) cells. Increased p53 mRNA expression was due to activation of the p53 promoter by hPitx1. hPitx1 bound directly to the p53 promoter and functionally utilized two hPitx1 consensus elements. The predominant consensus element utilized by hPitx1 to stimulate p53 transcription was located within the first exon of the p53 gene. A hPitx1 mutant (hPitx1-R141P) acting as a dominant inhibitor repressed p53 transcription. Forced expression of hPitx1 resulted in cell-cycle arrest and p53-dependent apoptosis in p53-replete MCF-7 cells. Furthermore, hPitx1 stimulated the transcription of p53 target genes involved in cell-cycle arrest and apoptosis (p21 and PTGF-beta), again in a p53-dependent manner. Depletion of endogenous hPitx1 by small interfering RNA (siRNA) in MCF-7 cells resulted in decreased basal expression of p53 and consequently of p21 and placental transforming growth factor beta (PTGF-beta). Depletion of p53 by siRNA dramatically attenuated hPitx1-induced apoptosis in MCF-7 cells. Thus, p53 is a direct transcriptional target gene of hPitx1. This observation is concordant with the recent identification of hPitx1 as a tumor suppressor gene.

Translation initiation at an upstream CUG codon regulates the expression of Hibiscus chlorotic ringspot virus coat protein

Viruses depend heavily on host cells for replication and exploit the host translation machinery for its gene expression using various unorthodox translation mechanisms. According to the conventional scanning model, only the 5'-proximal gene in the viral RNA is accessible to the ribosomes whereas other genes are silent. In this study, we use a model plant RNA virus, Hibiscus chlorotic ringspot virus (HCRSV), to investigate various translation mechanisms involved in regulation of the expression of internal genes. The 3'-end 1.2kb region of HCRSV genomic and subgenomic RNAs were shown to encode four polypeptides of 38, 27, 25 and 22.5kDa. Mutagenesis studies revealed that a CUG codon ((2570)CUG) is the initiation codon for p27, the longest of the three co-C-terminal products (p27, p25 and p22.5), and translation of p25 and p22.5 was initiated at (2603)AUG and (2666)AUG, respectively. Translation initiation of the p27 expression at the (2570)CUG codon regulates the expression of p38, the viral coat protein through a leaky scanning mechanism and mutational analysis of an upstream open reading frame (ORF) demonstrated that initiation of the p27 expression at this CUG codon (instead of an AUG) may play a role in maintaining the ratio of p27 and p38. In addition, a previously identified internal ribosome entry site was shown to control the expression of p27 and p38 in the subgenomic RNA 2.

Biochemical and functional characterization of Epstein-Barr virus-encoded BARF1 protein: interaction with human hTid1 protein facilitates its maturation and secretion

EBV BARF1 gene encodes a secretory protein with transforming and mitogenic activities. In this report, the post-translational modification, folding, maturation and secretion of BARF1 are systematically studied by site-directed mutagenesis and overexpression of the protein in mammalian cells using the vaccinia/T7 system. The protein was shown to be post-translationally modified by N-linked glycosylation on the asparagine 95 residue. This modification was confirmed to be essential for the maturation and secretion of the protein. Analysis of the four cysteine residues by site-directed mutagenesis demonstrated that cysteine 146 and 201 were essential for proper folding and secretion of the protein. To search for human proteins involved in the maturation process of the protein, a yeast two-hybrid screening was carried out using the BARF1 sequence from amino acids 21-221 (BARF1Delta) as bait, leading to the identification of human hTid1 protein as a potential interacting protein. This interaction was subsequently confirmed by coimmunoprecipitation and dual immunofluorescent labeling of cells coexpressing BARF1 and hTid1, and the interaction domain in hTid1 was mapped to amino acids 149-320. Interestingly, coexpression of BARF1 with hTid1 demonstrated that hTid1 could promote secretion of BARF1, suggesting that hTid1 may act as a chaperone to facilitate the folding, processing and maturation of BARF1.

Selection of and recombination between minor variants lead to the adaptation of an avian coronavirus to primate cells

An interesting question posed by the current evidence that severe acute respiratory syndrome coronavirus may be originated from an animal coronavirus is how such an animal coronavirus breaks the host species barrier and becomes zoonotic. In this report, we study the chronological order of genotypic changes in the spike protein of avian coronavirus infectious bronchitis virus (IBV) during its adaptation to a primate cell line. Adaptation of the Beaudette strain of IBV from chicken embryo to Vero cells showed the accumulation of 49 amino acid mutations. Among them, 26 (53.06%) substitutions were located in the S protein. Sequencing analysis and comparison of the S gene demonstrated that the majority of the mutations were accumulated and fixed at passage 7 on Vero cells and minor variants were isolated in several passages. Evidence present suggests that the dominant Vero cell-adapted IBV strain may be derived from the chicken embryo passages by selection of and potential recombination between the minor variants. This may explain why adaptation is a rapid process and the dominant strain, once adapted to a new host cell, becomes relatively stable.

Cell cycle molecules and vertebrate neuron death: E2F at the hub

Vertebrate neuron cell death is both a normal developmental process and the catastrophic outcome of nervous system trauma or degenerative disorders. Although the mechanisms of such death include an evolutionarily conserved core apoptotic pathway that is highly homologous to that first described by Horvitz and co-workers in Caenorhabditis elegans, it appears that many instances of neuron death additionally require the transcription-dependent induction of proapoptotic molecules. One such proapoptotic transcriptional pathway revealed by studies over the past decade revolves about the transcription factor E2F and those molecules that either regulate E2F activity or that are direct or indirect transcriptional targets of E2F. Many of the molecules associated with the E2F apoptotic pathway in postmitotic neurons also participate in the cell cycle in proliferating cells. Observations in human material and in animal and cell culture models show widespread correlation between changes in expression, activity and subcellular localization of E2F-related cell cycle molecules and developmental and catastrophic neuron death. A variety of experimental approaches support a causal role for such changes in the death process and are beginning to indicate how the neuronal E2F pathway activates the core apoptotic machinery. The discovery and elaboration of the neuronal apoptotic E2F pathway provides abundant targets as well as small molecule candidates for potential therapeutic intervention in nervous system trauma and degenerative disease.

Effects of cerulenin on the endogenous fatty acid synthetic activity in squamous cell carcinoma of the oral cavity

PURPOSES

Inhibition of cerulenin on the endogenous fatty acid synthetic activities of oral squamous cell carcinoma (OSCC) and normal oral mucosa was assayed.

METHODS

Squamous cell carcinoma and normal oral mucosa were collected fresh from surgical specimens. The collected tissues were minced in RPMI 1640 and divided into 3 groups: cerulenin treated, dimethylsulfoxide treated, and control. The tissues were incubated in [1(2)-(14)C]acetic acid, sodium salt for the last 2.5 hours of the treatment at 37 degrees C in 5% CO(2). After labeling, total lipids were extracted and counted for (14)C by scintillation counting.

RESULTS

Endogenous fatty acid synthetic activities of oral squamous cell caranoma in the cerulenin-treated group decreased by 19% at 1 hour, 64% at 2 hours, and 87% at 4 hours; remained nearly unchanged in the dimethylsulfoxide-treated group; and increased slightly in the control group. The oral mucosa tissues were only mildly affected by cerulenin in fatty acid synthesis.

CONCLUSIONS

Cerulenin significantly inhibits fatty acid synthetic activity in squamous cell carcinoma and only mildly affected the oral mucosa, indicating that the fatty acid synthetic pathway may be exploited as a target for developing anticancer drugs.

Emergence of a coronavirus infectious bronchitis virus mutant with a truncated 3b gene: functional characterization of the 3b protein in pathogenesis and replication

The subgenomic RNA 3 of IBV has been shown to be a tricistronic mRNA, encoding three products in IBV-infected cells. To explore if the least expressed ORF, ORF 3b, which encodes a nonstructural protein, is evolutionarily conserved and functionally indispensable for viral propagation in cultured cells, the Beaudette strain of IBV was propagated in chicken embryonated eggs for three passages and then adapted to a monkey kidney cell line, Vero. The 3b gene of passage 3 in embryonated eggs and passages 7, 15, 20, 25, 30, 35 50, and 65 in Vero cells were amplified by reverse transcription-polymerase chain reaction and sequenced. The results showed that viral RNA extracted from passages 35, 50, and 65 contained a single A insertion in a 6A stretch of the 3b gene between nucleotides 24075 and 24080, whereas the early passages carried the normal 3b gene. This insertion resulted in a frameshift event and therefore, if expressed, a C-terminally truncated protein. We showed that the frameshifting product, cloned in a plasmid, was expressed in vitro and in cells transfected with the mutant construct. The normal product of the 3b gene is 64 amino acids long, whereas the frameshifting product is 34 amino acids long with only 17 homogeneous amino acid residues at the N-terminal half. Immunofluorescent studies revealed that the normal 3b protein was localized to the nucleus and the truncated product showed a "free" distribution pattern, indicating that the C-terminal portion of 3b was responsible for its nuclear localization. Comparison of the complete genome sequences (27.6 kb) of isolates p20c22 and p36c12 (from passages 20 and 36, respectively) revealed that p36c12 contains three amino acid substitutions, two in the 195-kDa protein (encoded by gene 1) and one in the S protein, in addition to the frameshifting 3b product. Further characterization of the two isolates demonstrated that p36c12 showed growth advantage over p20c22 in both Vero cells and chicken embryos and was more virulent in chicken embryos than p20c22. These results suggest that the 3b gene product is not essential for the replication of IBV.

How we performed chest wall reconstruction: analysis 31 cases

OBJECTIVE

To see the results of patients who underwent chest wall resection and reconstruction (CWRR).

SETTING AND DESIGN

Retrospective descriptional study.

MATERIAL AND METHODS

We retrospectively reviewed all patients who underwent CWRR at Xingtai People's Hospital in China and B.P. Koirala Memorial Cancer Hospital in Nepal. A total of 31 patients were reviewed. Among them, 20 were male and 11 female. The median age was 63 years. The indications for resection were primary chest wall tumor in 21 patients (67.7%), lung cancer with invasion of chest wall 6 (19.4%), recurrence of breast cancer 2(6.3%), radiation necrosis 1(3.2%) and skin cancer 1(3.2%).

RESULTS

The mean number of rib resected was 3.6 ribs, which induced a mean defect of 97.1 cm2. Concomitant resection was done in 13 patients, including lung resection 10, partial resection of diaphragm 2, and partial sternectomy 1. Seven patients underwent soft tissue reconstruction (STR) alone and 5 patients skeletal reconstruction (SR) alone. Simultaneous SR and STR were performed in 19 patients. Three patients (9.7%) developed postoperative complications. The median survival period was 22 months.

CONCLUSION

Primary chest wall tumor and lung cancer invading chest wall are the most common diseases indicating CWRR. Simultaneous bony and soft tissue reconstruction was reliable for chest wall reconstruction in most cases and prevents postoperative complications.

Membrane association and dimerization of a cysteine-rich, 16-kilodalton polypeptide released from the C-terminal region of the coronavirus infectious bronchitis virus 1a polyprotein

More than 10 mature proteins processed from coronavirus gene 1-encoded polyproteins have been identified in virus-infected cells. Here, we report the identification of the most C-terminal cleavage product of the 1a polyprotein as a 16-kDa protein in infectious bronchitis virus-infected Vero cells. Indirect immunofluorescence demonstrated that the protein exhibits a distinct perinuclear punctate staining pattern, suggesting that it is associated with cellular membranes. Positive staining observed on nonpermeabilized cells indicates that the protein may get transported to the cell surface, but no secretion of the protein out of the cells was observed. Treatment of the membrane fraction prepared from cells expressing the 16-kDa protein with Triton X-100, a high pH, and a high concentration of salts showed that the protein may be tightly associated with intracellular membranes. Dual-labeling experiments demonstrated that the 16-kDa protein colocalized with the 5'-bromouridine 5'-triphosphate-labeled viral RNA, suggesting that it may be associated with the viral replication machinery. Sequence comparison of the 16-kDa protein with the equivalent products of other coronaviruses showed multiple conserved cysteine residues, and site-directed mutagenesis studies revealed that these conserved residues may contribute to dimerization of the 16-kDa protein. Furthermore, increased accumulation of the 16-kDa protein upon stimulation with epidermal growth factor was observed, providing preliminary evidence that the protein might be involved in the growth factor signaling pathway.

A six-nucleotide segment within the 3' untranslated region of hibiscus chlorotic ringspot virus plays an essential role in translational enhancement

RNA plant viruses use various translational regulatory mechanisms to control their gene expression. Translational enhancement of viral mRNAs that leads to higher levels of protein synthesis from specific genes may be essential for the virus to successfully compete for cellular translational machinery. The control elements have yet to be analyzed for members of the genus Carmovirus, a small group of plant viruses with positive-sense RNA genomes. In this study, we examined the 3' untranslated region (UTR) of hibiscus chlorotic ringspot virus (HCRSV) genomic RNA (gRNA) and subgenomic RNA (sgRNA) for its role in the translational regulation of viral gene expression. The results showed that the 3' UTR of HCRSV significantly enhanced the translation of several open reading frames on gRNA and sgRNA and a viral gene in a bicistronic construct with an inserted internal ribosome entry site. Through deletion and mutagenesis studies of both the bicistronic construct and full-length gRNA, we demonstrated that a six-nucleotide sequence, GGGCAG, that is complementary to the 3' region of the 18S rRNA and a minimal length of 180 nucleotides are required for the enhancement of translation induced by the 3' UTR.

Regulation of neuronal survival and death by E2F-dependent gene repression and derepression

Neuronal death induced by a variety of means requires participation of the E2F family of transcription factors. Here, we show that E2F acts as a gene silencer in neurons and that repression of E2F-responsive genes is required for neuronal survival. Moreover, neuronal death evoked by DNA damaging agents or trophic factor withdrawal is characterized by derepression of E2F-responsive genes. Such derepression, rather than direct E2F-promoted gene activation, is required for death. Among the genes that are derepressed in neurons subjected to DNA damage or trophic factor withdrawal are the transcription factors B- and C-myb. Overexpression of B- and C-myb is sufficient to evoke neuronal death. These findings support a model in which E2F-dependent gene repression and derepression play pivotal roles in neuronal survival and death, respectively.

Further identification and characterization of novel intermediate and mature cleavage products released from the ORF 1b region of the avian coronavirus infectious bronchitis virus 1a/1b polyprotein

The coronavirus 3C-like proteinase is one of the viral proteinases responsible for processing of the 1a and 1a/1b polyproteins to multiple mature products. In cells infected with avian coronavirus infectious bronchitis virus (IBV), three proteins of 100, 39, and 35 kDa, respectively, were previously identified as mature cleavage products released from the 1b region of the 1a/1b polyprotein by the 3C-like proteinase. In this report, we show the identification of two more cleavage products of 68 and 58 kDa released from the same region of the polyprotein. In addition, two stable intermediate cleavage products with molecular masses of 160 and 132 kDa, respectively, were identified in IBV-infected cells. The 160-kDa protein was shown to be an intermediate cleavage product covering the 100- and 68-kDa proteins, and the 132-kDa protein to be an intermediate cleavage product covering the 58-, 39-, and 35-kDa proteins. Immunofluorescent staining of IBV-infected cells and cells expressing individual cleavage products showed that the 100-, 68-, and 58-kDa proteins were associated with the membranes of the endoplasmic reticulum, and the 39- and 35-kDa proteins displayed diffuse distribution patterns.

Differential molecular assemblies underlie the dual function of Axin in modulating the WNT and JNK pathways

Axin is a multidomain scaffold protein that exerts a dual function in the Wnt signaling and MEKK1/JNK pathways. This raises a critical question as to whether Axin-based differential molecular assemblies exist and how these may act to coordinate the two separate pathways. Here we show that both wild-type glycogen synthase kinase-3 beta (GSK-3 beta) and kinase-dead GSK-3 beta-Y216F (capable of binding to Axin), but not GSK-3 beta-K85M (incapable of binding to Axin in mammalian cells), prevented MEKK1 binding to the Axin complex, thereby inhibiting JNK activation. We further show that casein kinase I epsilon also inhibited Axin-mediated JNK activation by competing against MEKK1 binding. In contrast, beta-catenin and adenomatous polyposis coli binding did not affect MEKK1 binding to the same Axin complex. This suggests that even when Axin is "switched" to activate the JNK pathway, it is still capable of sequestering free beta-catenin, which is a critical aspect for cellular homeostasis. Our results clearly demonstrate that differential molecular assemblies underlie the duality of Axin functions in the negative regulation of Wnt signaling and activation of the JNK MAPK pathway.

The application of chiral aminonaphthols in the enantioselective addition of diethylzinc to aryl aldehydes

[reaction: see text]. Optically active aminonaphthol 3 obtained by condensation of 2-naphthol, benzaldehyde, and (S)-methylbenzylamine followed by N-methylation was found to catalyze the enantioselective ethylation of aryl aldehydes to secondary alcohols with high enantioselectivities (up to 99.8%) at room temperature.

Neuronal apoptosis at the G1/S cell cycle checkpoint

Apoptosis is a fundamental and essential process in development and tissue homeostasis of multicellular organisms. Roughly half of all the neurons produced during neurogenesis die apoptotically before the nervous system matures. Apoptosis is also involved in various neurodegenerative disorders such as Alzheimer's disease and neuronal trauma. Investigation of the mechanisms underlying neuronal apoptosis led to an unexpected discovery that in many cases revival of the quiescent and dormant cell cycle machinery is a common theme. Recent data suggest that uncoordinated expression of cell cycle molecules and the consequent breach of cell cycle checkpoints could be one of the primary mechanisms by which postmitotic neurons undergo apoptotic death. Evidence indicates that upregulation of cyclin-D-CDK4/6 activity and deregulation of E2F transcription factors mark key events in early stages of neuronal apoptosis. Active E2F repression by Rb family members is required for the survival of neurons. Apoptotic signals promote successive phosphorylation and dysfunction of Rb family members, resulting in sequential E2F derepression and expression of selective E2F-responsive genes. Thus, expression of derepressed E2F-responsive genes may be instrumental in propagating and amplifying the apoptotic signals instructing neuronal cells to carry out the apoptotic program.

A new hypothesis of pathogenetic mechanism of viral hepatitis B and C

The experimental data in recent years suggest apoptosis of liver cells plays a significant role in the pathogenesis of viral hepatitis. Firstly, the number of apoptotic hepatocytes in patients with hepatitis B or C is significantly higher than healthy objects. Secondly, the expression levels of Fas antigen in hepatocytes of patients with hepatitis B or C are closely correlated with inflammation activity. Thirdly, massive apoptosis of hepatocyte will result in fulminant hepatitis, while inhibition of apoptosis can prevent inflammation in experimental model of liver injury. And finally, the occurrence of hepatitis induced by CTL in transgenic mice is a process from hepatocyte apoptosis to liver necroinflammation. This paper will examine our current understanding of the possible relationship between hepatocellular apoptosis and the pathogenetic mechanism of hepatitis B and C.

Induction of caspase-dependent apoptosis in cultured cells by the avian coronavirus infectious bronchitis virus

Avian coronavirus infectious bronchitis virus (IBV) is the causative agent of chicken infectious bronchitis, an acute, highly contagious viral respiratory disease. Replication of IBV in Vero cells causes extensive cytopathic effects (CPE), leading to destruction of the entire monolayer and the death of infected cells. In this study, we investigated the cell death processes during acute IBV infection and the underlying mechanisms. The results show that both necrosis and apoptosis may contribute to the death of infected cells in lytic IBV infection. Caspase-dependent apoptosis, as characterized by chromosomal condensation, DNA fragmentation, caspase-3 activation, and poly(ADP-ribose) polymerase degradation, was detected in IBV-infected Vero cells. Addition of the general caspase inhibitor z-VAD-FMK to the culture media showed inhibition of the hallmarks of apoptosis and increase of the release of virus to the culture media at 16 h postinfection. However, neither the necrotic process nor the productive replication of IBV in Vero cells was severely affected by the inhibition of apoptosis. Screening of 11 IBV-encoded proteins suggested that a 58-kDa mature cleavage product could induce apoptotic changes in cells transiently expressing the protein. This study adds one more example to the growing list of animal viruses that induce apoptosis during their replication cycles.