[Molecular mechanisms of quinolone resistance in non-typhoidal Salmonella]

By conducting retrospective analysis, this study aim to investigate the resistance mechanism of quinolones in non-typhoidal Salmonella (NTS). A total of 105 strains of NTS isolated from clinical specimens from the Fifth Affiliated Hospital of Southern Medical University from May 2020 to February 2021 were used as research objects. VITEK2 Compact automatic identification drug sensitivity analysis system and serological test were used to identify the strains. The sensitivity of the strains to ciprofloxacin, levofloxacin and nalidixic acid was detected by AGAR dilution method. The whole genome of 105 strains of NTS was sequenced. Abricate and other softwares were used to analyze drug-resistant genes, including plasmid-mediated quinolone resistance gene (PMQR) and Quinolone resistance determination region (QRDR). Serotypes and ST types were analyzed using SISTR and MLST, and phylogenetic trees were constructed. The results showed that the NTS isolated in this region were mainly ST34 Salmonella typhimurium (53.3%). The drug sensitivity results showed that the drug resistance rates of NTS to ciprofloxacin, levofloxacin and nalidixic acid were 30.4%, 1.9% and 22.0%, respectively, and the intermediate rates of ciprofloxacin and levofloxacin were 27.6% and 54.2%.A total of 46 (74.2%) of the 62 quinolone non-susceptible strains carried the PMQR gene, mainly qnrS1 (80.4%), followed by aac(6')-Ib-cr(15.2%); there were 14 NTS and 8 NTS had gyrA and parC gene mutations, respectively. The gyrA was mutations at the amino acid position 87, Asp87Tyr, Asp87Asn, Asp87Gly, and Thr57Ser mutations were detected in parC. In conclusion, this study found that NTS had relatively high resistance to quinolones, carrying qnrS1 gene mainly resulted in decreased sensitivity of NTS to ciprofloxacin and levofloxacin, and gyrA:87 mutation mainly resulted in NTS resistance to Nalidixic acid; Salmonella typhimurium in clinical isolates showed clonal transmission and required further epidemiological surveillance.

Increasing dominance of Indian Ocean variability impacts Australian wheat yields

The relationships between crop productivity and climate variability drivers are often assumed to be stationary over time. However, this may not be true in a warming climate. Here we use a crop model and a machine learning algorithm to demonstrate the changing impacts of climate drivers on wheat productivity in Australia. We find that, from the end of the nineteenth century to the 1980s, wheat productivity was mainly subject to the impacts of the El Niño Southern Oscillation. Since the 1990s, the impacts from the El Niño Southern Oscillation have been decreasing, but those from the Indian Ocean Dipole have been increasing. The warming climate has brought more occurrences of positive Indian Ocean Dipole events, resulting in severe yield reductions in recent decades. Our findings highlight the need to adapt seasonal forecasting to the changing impacts of climate variability to inform the management of climate-induced yield losses.

Extreme fire weather is the major driver of severe bushfires in southeast Australia

In Australia, the proportion of forest area that burns in a typical fire season is less than for other vegetation types. However, the 2019-2020 austral spring-summer was an exception, with over four times the previous maximum area burnt in southeast Australian temperate forests. Temperate forest fires have extensive socio-economic, human health, greenhouse gas emissions, and biodiversity impacts due to high fire intensities. A robust model that identifies driving factors of forest fires and relates impact thresholds to fire activity at regional scales would help land managers and fire-fighting agencies prepare for potentially hazardous fire in Australia. Here, we developed a machine-learning diagnostic model to quantify nonlinear relationships between monthly burnt area and biophysical factors in southeast Australian forests for 2001-2020 on a 0.25° grid based on several biophysical parameters, notably fire weather and vegetation productivity. Our model explained over 80% of the variation in the burnt area. We identified that burnt area dynamics in southeast Australian forest were primarily controlled by extreme fire weather, which mainly linked to fluctuations in the Southern Annular Mode (SAM) and Indian Ocean Dipole (IOD), with a relatively smaller contribution from the central Pacific El Niño Southern Oscillation (ENSO). Our fire diagnostic model and the non-linear relationships between burnt area and environmental covariates can provide useful guidance to decision-makers who manage preparations for an upcoming fire season, and model developers working on improved early warning systems for forest fires.

Seasonal Predictions of Summer Precipitation in the Middle-lower Reaches of the Yangtze River with Global and Regional Models Based on NUIST-CFS1.0

Accurate prediction of the summer precipitation over the middle and lower reaches of the Yangtze River (MLYR) is of urgent demand for the local economic and societal development. This study assesses the seasonal forecast skill in predicting summer precipitation over the MLYR region based on the global Climate Forecast System of Nanjing University of Information Science and Technology (NUIST-CFS1.0, previously SINTEX-F). The results show that the model can provide moderate skill in predicting the interannual variations of the MLYR rainbands, initialized from 1 March. In addition, the nine-member ensemble mean can realistically reproduce the links between the MLYR precipitation and tropical sea surface temperature (SST) anomalies, but the individual members show great discrepancies, indicating large uncertainty in the forecasts. Furthermore, the NUIST-CFS1.0 can predict five of the seven extreme summer precipitation anomalies over the MLYR during 1982-2020, albeit with underestimated magnitudes. The Weather Forecast and Research (WRF) downscaling hindcast experiments with a finer resolution of 30 km, which are forced by the large-scale information of the NUIST-CFS1.0 predictions with a spectral nudging method, display improved predictions of the extreme summer precipitation anomalies to some extent. However, the performance of the downscaling predictions is highly dependent on the global model forecast skill, suggesting that further improvements on both the global and regional climate models are needed.

Over-projected Pacific warming and extreme El Niño frequency due to CMIP5 common biases

Extreme El Niño events severely disrupt the global climate, causing pronounced socio-economic losses. A prevailing view is that extreme El Niño events, defined by total precipitation or convection in the Niño3 area, will increase 2-fold in the future. However, this projected change was drawn without removing the potential impacts of Coupled Model Intercomparison Project phase 5 (CMIP5) models’ common biases. Here, we find that the models’ systematic biases in simulating tropical climate change over the past century can reduce the reliability of the projected change in the Pacific sea surface temperature (SST) and its related extreme El Niño frequency. The projected Pacific SST change, after removing the impacts of 13 common biases, displays a ‘La Niña-like’ rather than ‘El Niño-like’ change. Consequently, the extreme El Niño frequency, which is highly linked to the zonal distribution of the Pacific SST change, would remain mostly unchanged under CMIP5 warming scenarios. This finding increases confidence in coping with climate risks associated with global warming.

Decadal climate variability in the tropical Pacific: Characteristics, causes, predictability, and prospects

[Figure: see text].

[Depression symtoms and related factors of fire fighters]

Objective: To analysis the status of the mental health and related factors of fire fighters in Tianjin Binhai New District, and to provide suggestions for their psychological health protection. Methods: 399 fire fighters in Tianjin Binhai New District were selected as study subjects in Jan to April 2019. Depression symptoms were measured by the depression module of the Patient Health Questionnaire (PHQ-9) . The Chinese version of Efrort Reword Imbalance (ERI) Questionnnaire were used to investigate and evaluate their occupational stress. Chi-Square test was used to analysis Categorical data. Binary logistic regression model was used to analysis the ralated factors of depression. Results: Among the 399 fire fighters, 71.1% (280/394) were found high level of depression symptom. The detection rates of depression symptoms in the related influceing factors ERI、station、disease、life pressure、eating habits and sleep disorder occupational stress were difierent (P<0.05) . Sleep disorder, life pressure and ERI occupational stress were risk factors for depressive symptoms (OR=1.921, 95% CI=1.002-3.682; OR=2.852, 95% CI=1.561-5.212; OR=2.367, 95% CI=1.163-4.818, P<0.05) . Conclusion: The rate of depression of fire fighters is relatively higher. Government should pay attention to and take measures to improve the psychological condition of fire fighters.

[CD44 regulates biological behavior and Ras signaling pathway in nasopharyngeal carcinoma stem cells]

Objective: To study the biological behavior of nasopharyngeal carcinoma stem cells and to explore the activation of Ras signaling pathway regulated by CD44. Methods: CNE2-SC and 5-8F-SC were nasopharyngeal carcinoma stem cells and obtained by serum-free suspension culture. Cell counting kit-8 (CCK-8) assay, colony formation assay, Transwell migration assay, cell adhesion array were used to investigate the growth, proliferation, migration and adhesion of nasopharyngeal carcinoma stem cells. Western blot test was used to detect the expressions of Ras signaling pathway related proteins and siRNA-mediated interference was used to determine the activation of Ras signaling pathway regulated by CD44. Results: The growth rates of CNE2-SC and 5-8F-SC cells were significantly lower than those of nasopharyngeal carcinoma cells at 24, 48 and 72 hours after inoculation (P<0.05). After 14 days of implantation, the colony formation rates of CNE2-SC (44.5±1.9)% and 5-8F-SC (47.4±1.8)% were higher than those of CNE2 (34.9±1.5)% and 5-8F (37.2±1.7)%, respectively(P<0.01). The migration cell number of CNE2-SC was (87.6±7.8), 3.97 times higher than that of CNE2 (P<0.01). The migration cell number of 5-8F-SC was (67.2±5.7), 3.07 times higher than 5-8F (P<0.01). The adhesion rates of CNE2-SC and CNE2 cells were (42.1±7.6)% and (8.9±2.0)%, respectively at 3 hours after inoculation and were (82.4±5.0)% and (12.1±2.2)% at 6 hours after inoculation, respectively. The adhesion rate of CNE2-SC cells was higher than that of CNE2 cells (all P<0.01). The adhesion rates of 5-8F-SC and 5-8F cells were (53.6±6.1)% and (7.3±1.5)% at 3 hours after inoculation, and (90.7±3.6)% and (11.0±1.2)% at 6 hours after inoculation, respectively. The adhesion rate of 5-8F-SC cells was higher than that of 5-8F cells (P<0.01). The expression levels of CD44, Ras and N-cadherin were significantly higher, while phosphatase and tensin homolog deleted on chromosome 10 (PTEN), E-cadherin in nasopharyngeal carcinoma stem cells were lower than those of the nasopharyngeal carcinoma cells. Furthermore, the levels of phosphorylated mitogen extracellular kinase1/2 (p-MEK1/2) and phosphorylated extracellular signal-regulated protein kinase1/2 (p-ERK1/2)were significantly increased in nasopharyngeal carcinoma stem cells (P<0.01). Correlation analysis showed that the protein expression levels of CD44 was highly positively correlated with RAS in nasopharyngeal carcinoma stem cells(r=0.985, P=0.002; r=0.962, P=0.038). Deletion of CD44 in CNE2-SC decreased the expression levels of HER-2, Ras and p-ERK1/2, p-Akt and phosphorylated protein kinase C-δ(p-PKCδ) (P<0.01). Conclusions: Despite compare to the nasopharyngeal carcinoma cell, nasopharyngeal carcinoma stem cells grows at a relatively slow rate, the capacities of clone formation, migration, adhesion are promoted. This may be related to the CD44-regulated abnormal activation of Ras signaling pathway.

[Hemodynamic response in cirrhotic patients with transjugular intrahepatic portosystemic shunt]

Objective: To discuss the effects of transjugular intrahepatic portosystemic shunt (TIPS) procedure on hemodynamics in cirrhotic patients. Methods: A total of 23 cirrhotic patients for TIPS insertion were enrolled from January 2018 to October 2018. Serum N-terminal pro-B-type natriuretic peptide (NT-proBNP), transthoracic echocardiography and non-invasive cardiac output measurement based on impedance cardiogram were carried out before and 24h, 1 month, 6 months after TIPS in order to observe cardiac function and hemodynamic changes after TIPS. Results: Significant increases in right atrial area [(17.2±4.0) cm(2) vs. (15.0±3.4) cm(2), P<0.05], right ventricular area [(15.1±3.8) cm(2) vs. (13.7±3.5) cm(2), P<0.05] and left ventricular volume [(97.4±21.5) ml vs. (91.1±22.7) ml, P<0.05] were observed 24 h after TIPS. These changes were accompanied with significant reduction in collapsible index of inferior vena cava [(20.7± 8.1)% vs. (28.6±11.3)%, P<0.01] and elevation in pulmonary arterial systolic pressure [(36.0±8.4) mmHg (1 mmHg=0.133 kPa) vs. (31.8±5.4) mmHg, P<0.01]. There also existed significantly elevated serum NT-proBNP [(551.2±325.1) ng/L vs. (124.2±94.4) ng/L, P<0.01], cardiac output [(5.82±0.96) L/min vs. (5.12±1.28) L/min, P<0.01], cardiac index [(3.47±0.64) L·min(-1)·m(-2) vs. (3.05±0.78) L·min(-1)·m(-2), P<0.01], early diastolic filling rate [(59.0±14.3)% vs. (54.5±11.0)%, P<0.05], and reduced systemic vascular resistance index (SVRi) [(1 798.4±357.3) dyne·s·cm(-5)·m(-2) vs. (2 195.7±508.7) dyne·s·cm(-5)·m(-2), P<0.01] 24 h after TIPS. At the end of 6-month follow-up, all these parameters, but not SVRi, returned towards baseline values. Moreover, peak early to late diastolic tissue velocity ratio at the level of lateral mitral annulus (E'/A') was significantly higher at the end of 6-month follow-up than that at baseline (1.06±0.32 vs. 0.90±0.45, P<0.05). Neither the right ventricular fractional area changes nor the left ventricular ejection fractions during the follow-up period were different from those at baseline (P>0.05). Conclusion: Cirrhotic patients who had no cardiovascular pathologies had adequate adaptation and good compensation ability to reach a new hemodynamic homeostasis for the increased volume load after TIPS insertion.

Using large-scale climate drivers to forecast meteorological drought condition in growing season across the Australian wheatbelt

Recurring drought has caused large crop yield losses in Australia during past decades. Long-term drought forecasting is of great importance for the development of risk management strategies. Recently, large-scale climate drivers (e.g. El Niño-Southern Oscillation) have been demonstrated as useful in the application of drought forecasting. Machine learning-based models that use climate drivers as input are commonly adopted to provide drought forecasts as these models are easy to develop and require less information compared to physical-based models. However, few machine learning-based models have been developed to forecast drought conditions during growing season across all Australian cropping areas. In this study, we developed a growing season (Apr.-Nov.) meteorological drought forecasting model for each climate gauging location across the Australian wheatbelt based on multiple lagged (past) large-scale climate indices and the Random Forest (RF) algorithm. The Standardized Precipitation Index (SPI) was used as the response variable to measure the degree of meteorological drought. Results showed that the RF model could provide satisfactory drought forecasts in the eastern areas of the wheatbelt with Pearson's correlation coefficient r > 0.5 and normalized Root Mean Square Error (nRMSE) < 23%. Forecasted drought maps matched well with observed drought maps for three representative periods. We identified NINO3.4 sea surface temperature and Multivariate ENSO Index as the most influential indices dominating growing season drought conditions across the wheatbelt. In addition, lagged impacts of large-scale climate drivers on growing season drought conditions were long-lasting and the indices in previous year could also potentially affect drought conditions during current year. As large-scale climate indices are readily available and can be rapidly used to feed data driven models, we believe the proposed meteorological drought forecasting models can be easily extended to other regions to provide drought outlooks which can help mitigate adverse drought impacts.

[Distribution characteristics and correlation analysis of antibody detection value in myasthenia gravis]

Objective: To determine the factors affecting distribution and magnitude of antibody detection value in myasthenia gravis (MG). Methods: A total of 406 MG patients diagnosed at Department of Neurology, Peking University First Hospital from May 2015 to November 2017 were included.All of them exhibited muscle fatigue with decreased response in repetitive nerve stimulation test. There were 200 males and 206 females whose ages ranged from 2 to 85 years old. According to clinical classification of MG recommended by Myasthenia Gravis Foundation of America (MGFA), patients assigned to class I to class V included 200,140, 46, 15 and 5 cases, respectively. There were 33 cases of thymic hyperplasia and 63 cases of thymoma confirmed by radiological or pathological findings. Quantile plots and quantile regression model were used to determine the effects of age, gender and MGFA classification, thymus disease on acetylcholine receptors (AChR)antibody, acetylcholinesterase (AChE) antibody, Titin antibody, ryanodine receptor (RyR) antibody and muscle-specific tyrosine kinase (MuSK) antibody detection values detected by enzyme-linked immunosorbent assay (ELISA). Results: MGFA classification had effects on distribution of AChR antibody level. There was a positive correlation between age and AChR antibody level(P<0.05). Negative correlation was found between age and AChE, Titin and RyR antibody level (P<0.05). No significant correlation was shown between any factors and MuSK antibody level(P≥0.05). MGFA classification had a positive correlation with AChR antibody level (P<0.05) and no correlation with other antibody levels (P>0.05). Gender and thymus disease had no correlation with any tested antibody levels (P>0.05). Conclusion: MGFA classification has significant effects on distribution of AChR antibody level. Age and MGFA classification have positive correlation with AChR antibody level.

Pantropical climate interactions

The El Niño-Southern Oscillation (ENSO), which originates in the Pacific, is the strongest and most well-known mode of tropical climate variability. Its reach is global, and it can force climate variations of the tropical Atlantic and Indian Oceans by perturbing the global atmospheric circulation. Less appreciated is how the tropical Atlantic and Indian Oceans affect the Pacific. Especially noteworthy is the multidecadal Atlantic warming that began in the late 1990s, because recent research suggests that it has influenced Indo-Pacific climate, the character of the ENSO cycle, and the hiatus in global surface warming. Discovery of these pantropical interactions provides a pathway forward for improving predictions of climate variability in the current climate and for refining projections of future climate under different anthropogenic forcing scenarios.

El Niño-Southern Oscillation complexity

El Niño events are characterized by surface warming of the tropical Pacific Ocean and weakening of equatorial trade winds that occur every few years. Such conditions are accompanied by changes in atmospheric and oceanic circulation, affecting global climate, marine and terrestrial ecosystems, fisheries and human activities. The alternation of warm El Niño and cold La Niña conditions, referred to as the El Niño-Southern Oscillation (ENSO), represents the strongest year-to-year fluctuation of the global climate system. Here we provide a synopsis of our current understanding of the spatio-temporal complexity of this important climate mode and its influence on the Earth system.

Mouse Models for Studying Oral Cancer: Impact in the Era of Cancer Immunotherapy

Model systems for oral cancer research have progressed from tumor epithelial cell cultures to in vivo systems that mimic oral cancer genetics, pathological characteristics, and tumor-stroma interactions of oral cancer patients. In the era of cancer immunotherapy, it is imperative to use model systems to test oral cancer prevention and therapeutic interventions in the presence of an immune system and to discover mechanisms of stromal contributions to oral cancer carcinogenesis. Here, we review in vivo mouse model systems commonly used for studying oral cancer and discuss the impact these models are having in advancing basic mechanisms, chemoprevention, and therapeutic intervention of oral cancer while highlighting recent discoveries concerning the role of immune cells in oral cancer. Improvements to in vivo model systems that highly recapitulate human oral cancer hold the key to identifying features of oral cancer initiation, progression, and invasion as well as molecular and cellular targets for prevention, therapeutic response, and immunotherapy development.

[Evaluation of a high-intensity fluorescent fluorophage method for diagnosis of drug-resistance in tuberculosis]

Objective: To evaluate the high-intensity green fluorescent protein fluorophage Φ(2)GFP10 method for drug susceptibility testing of tuberculosis for isoniazid(INH), rifampin(RIF), and streptomycin(SM). Methods: A total of 128 clinical M. tuberculosis strains were isolated from patients with suspected drug-resistant tuberculosis visiting Beijing Chest Hospital (Beijing, China) from April to June 2014.All of the isolates were tested by the phage assay, while conventional drug susceptibility tests were performing on Lwenstein-Jensen culture medium as reference. Results: The sensitivities of Φ(2)GFP10 assay for INH, RIF, and SM resistance detection were 100.0%, 98.1%(53/54), and 92.6%(50/54), respectively, while their specificities were 84.8%(56/66), 91.9%(68/74), and 91.9%(68/74), respectively. The agreement between the phage assay and the conventional assay for detecting INH, RIF, and SM resistance was 0.92, 0.95 and 0.92, respectively. The Φ(2) GFP10-phage assay could be done within 2 days for RIF and SM, and 3 days for INH. Conclusions: The Φ(2)GFP10-phage method for drug susceptibility test is very sensitive and specific. The method has the potential to be a valuable, rapid and economical screening method for detecting drug-resistant tuberculosis.

Inter-basin sources for two-year predictability of the multi-year La Niña event in 2010-2012

Multi-year La Niña events often induce persistent cool and wet climate over global lands, altering and in some case mitigating regional climate warming impacts. The latest event lingered from mid-2010 to early 2012 and brought about intensive precipitation over many land regions of the world, particularly Australia. This resulted in a significant drop in global mean sea level despite the background upwards trend. This La Niña event is surprisingly predicted out to two years ahead in a few coupled models, even though the predictability of El Niño-Southern Oscillation during 2002-2014 has declined owing to weakened ocean-atmosphere interactions. However, the underlying mechanism for high predictability of this multi-year La Niña episode is still unclear. Experiments based on a climate model that demonstrates a successful two-year forecast of the La Niña support the hypothesis that warm sea surface temperature (SST) anomalies in the Atlantic and Indian Oceans act to intensify the easterly winds in the central equatorial Pacific and largely contribute to the occurrence and two-year predictability of the 2010-2012 La Niña. The results highlight the importance of increased Atlantic-Indian Ocean SSTs for the multi-year La Niña's predictability under global warming.

The reliability of the Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) among dermatologists, rheumatologists and neurologists

BACKGROUND

Previous studies have shown that skin disease in dermatomyositis (DM) is best assessed using the Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI). Although the CDASI has been validated for use by dermatologists, it has not been validated for use by other physicians such as rheumatologists and neurologists, who also manage patients with DM and assess skin activity in clinical trials.

OBJECTIVES

To assess the reliability of the CDASI among dermatologists, rheumatologists and neurologists.

METHODS

Fifteen patients with cutaneous DM were assessed using the CDASI and the Physician Global Assessment (PGA) by five dermatologists, five rheumatologists and five neurologists.

RESULTS

The mean CDASI activity scores for dermatologists, rheumatologists and neurologists were 21·0, 21·8 and 20·8, respectively. These mean scores were not different among the specialists. The CDASI damage score means for dermatologists, rheumatologists and neurologists were 5·3, 7·0 and 4·8, respectively. The mean scores between dermatologists and rheumatologists were significantly different, but the means between dermatologists and neurologists were not. The intraclass correlation coefficients (ICCs) for interrater reliability for CDASI activity and damage were good to excellent for dermatologists and rheumatologists, and moderate to excellent for neurologists. The ICCs for intrarater reliability for CDASI activity and damage were excellent for dermatologists and rheumatologists and moderate to excellent for neurologists. The PGA displayed lower interrater and intrarater reliability relative to the CDASI.

CONCLUSIONS

Our results confirm the reliability of the CDASI when used by dermatologists and rheumatologists. The data for its use by neurologists were not as robust.

Robust contribution of decadal anomalies to the frequency of central-Pacific El Niño

During year-to-year El Niño events in recent decades, major sea surface warming has occurred frequently in the central Pacific. This is distinct from the eastern Pacific warming pattern during canonical El Niño events. Accordingly, the central-Pacific El Niño exerts distinct impacts on ecosystems, climate and hurricanes worldwide. The increased frequency of the new type of El Niño presents a challenge not only for the understanding of El Niño dynamics and its change but also for the prediction of El Niño and its global impacts at present and future climate. Previous studies have proposed different indices to represent the two types of El Niño for better understanding, prediction and impact assessment. Here, we find that all popularly used indices for the central-Pacific El Niño show a dominant spectral peak at a decadal period with comparatively weak variance at interannual timescales. Our results suggest that decadal anomalies have an important contribution to the occurrence of the central-Pacific El Niño over past decades. Removing the decadal component leads to a significant reduction in the frequency of the central-Pacific El Niño in observations and in Coupled Model Intercomparison Project Phase 5 simulations of preindustrial, historical and future climate.

[Clinical value of contrast-enhanced ultrasound in evaluating portal hypertension in patients with decompensated liver cirrhosis]

OBJECTIVE

To investigate the correlation between contrast-enhanced ultrasound parameters and hepatic venous pressure gradient (HVPG), and to develop a new noninvasive method for the evaluation of portal hypertension in patients with decompensated liver cirrhosis.

METHODS

One-hundred patients with decompensated liver cirrhosis were examined by contrast-enhanced ultrasound, and the dynamic images were collected for offline analysis. The contrast arrival time was obtained in the hepatic artery (HA), portal vein (PV), and hepatic vein (HV), and HA-HV transit time (HA-HVTT) and PV-HV transit time (PV-HVTT) were calculated. At the same time, HVPG was measured within 24 hours after contrast-enhanced ultrasound, Pearson correlation analysis was performed between each parameter and HVPG, and the receiver operating characteristic (ROC) curve was also used for analysis.

RESULTS

HV arrival time (HVAT), HA-HVTT, and PV-HVTT were negatively correlated with HVPG (r = -0.385, -0.409, and -0.572, respectively). The area under the ROC curve (AUROC) was 0.903 for PV-HVTT < 2.5 s in judging HVPG≥ l0 mmHg in patients with decompensated liver cirrhosis, and the sensitivity and specificity were 74.4% and 89.5%, respectively. The AUROC was 0.861 for PV-HVTT < 1.5 s in judging HVPG≥l6 mmHg in these patients, and the sensitivity and specificity were 80.4% and 81.5%, respectively.

CONCLUSIONS

HVAT and intrahepatic transit time demonstrate negative linear correlations with HVPG in patients with decompensated liver cirrhosis, and among all parameters, PV-HVTT shows the strongest correlation with HVPG and can be used to determine and predict the severity of portal hypertension.

Skilful multi-year predictions of tropical trans-basin climate variability

Tropical Pacific sea surface temperature anomalies influence the atmospheric circulation, impacting climate far beyond the tropics. The predictability of the corresponding atmospheric signals is typically limited to less than 1 year lead time. Here we present observational and modelling evidence for multi-year predictability of coherent trans-basin climate variations that are characterized by a zonal seesaw in tropical sea surface temperature and sea-level pressure between the Pacific and the other two ocean basins. State-of-the-art climate model forecasts initialized from a realistic ocean state show that the low-frequency trans-basin climate variability, which explains part of the El Niño Southern Oscillation flavours, can be predicted up to 3 years ahead, thus exceeding the predictive skill of current tropical climate forecasts for natural variability. This low-frequency variability emerges from the synchronization of ocean anomalies in all basins via global reorganizations of the atmospheric Walker Circulation.

Sea surface temperature anomalies in the tropical Pacific can influence global atmospheric circulation, yet prediction of this atmospheric signal is limited to less than 1 year. Here, the authors present observational and modelling evidence for multi-year predictability.

Phoenixin: a novel peptide in rodent sensory ganglia

Phoenixin-14 amide, herein referred to as phoenixin, is a newly identified peptide from the rat brain. Using a previously characterized rabbit polyclonal antiserum against phoenixin, enzyme-immunoassay detected a high level (>4.5 ng/g tissue) of phoenixin-immunoreactivity (irPNX) in the rat spinal cords. Immunohistochemical studies revealed irPNX in networks of cell processes in the superficial dorsal horn, spinal trigeminal tract and nucleus of the solitary tract; and in a population of dorsal root, trigeminal and nodose ganglion cells. The pattern of distribution of irPNX in the superficial layers of the dorsal horn was similar to that of substance P immunoreactivity (irSP). Double-labeling the dorsal root ganglion sections showed that irPNX and irSP express in different populations of ganglion cells. In awake mice, intrathecal injection of phoenixin (1 or 5 μg) did not significantly affect the tail-flick latency as compared to that in animals injected with artificial cerebrospinal fluid (aCSF). Intrathecal administration of phoenixin (0.5, 1.25 or 2.5 μg) significantly reduced the number of writhes elicited by intraperitoneal injection of acetic acid (0.6%, 0.3 ml/30 g) as compared to that in mice injected with aCSF. While not affecting the tail-flick latency, phoenixin antiserum (1:100) injected intrathecally 10 min prior to the intraperitoneal injection of acetic acid significantly increased the number of writhes as compared to mice pre-treated with normal rabbit serum. Intrathecal injection of non-amidated phoenixin (2.5 μg) did not significantly alter the number of writhes evoked by acetic acid. Our result shows that phoenixin is expressed in sensory neurons of the dorsal root, nodose and trigeminal ganglia, the amidated peptide is bioactive, and exogenously administered phoenixin may preferentially suppress visceral as opposed to thermal pain.

Irisin-immunoreactivity in neural and non-neural cells of the rodent

Irisin is a recently identified myokine secreted from the muscle in response to exercise. In the rats and mice, immunohistochemical studies with an antiserum against irisin peptide fragment (42-112), revealed that irisin-immunoreactivity (irIRN) was detected in three types of cells; namely, skeletal muscle cells, cardiomyocytes, and Purkinje cells of the cerebellum. Tissue sections processed with irisin antiserum pre-absorbed with the irisin peptide (42-112) (1 μg/ml) showed no immunoreactivity. Cerebellar Purkinje cells were also immunolabeled with an antiserum against fibronectin type II domain containing 5 (FNDC5), the precursor protein of irisin. Double-labeling of cerebellar sections with irisin antiserum and glutamate decarboxylase (GAD) antibody showed that nearly all irIRN Purkinje cells were GAD-positive. Injection of the fluorescence tracer Fluorogold into the vestibular nucleus of the rat medulla retrogradely labeled a population of Purkinje cells, some of which were also irIRN. Our results provide the first evidence of expression of irIRN in the rodent skeletal and cardiac muscle, and in the brain where it is present in GAD-positive Purkinje cells of the cerebellum. Our findings together with reports by others led us to hypothesize a novel neural pathway, which originates from cerebellum Purkinje cells, via several intermediary synapses in the medulla and spinal cord, and regulates adipocyte metabolism.

High-Aspect-Ratio Aluminum Borate Nanowire Bundles Supported by Sucrose

High-aspect-ratio and single-crystal aluminum borate (Al(18)B(4)O(33)) nanowire bundles with an ordered orientation were synthesized by using an innovative sucrose-assisted growth process. The process involves the dehydration and polycondensation of aluminum borate-sucrose solution to form a highly viscous precursor. The sucrose plays a crucial role in the growth of the nanowire bundles by supporting as a polymeric substrate and a type of adhesive template. Electron microscopy was used to characterize the high-aspect-ratio nanowire bundles. A possible growth mechanism for the nanowire bundles is proposed.

Characterization of the neurotrophic interaction between nerve growth factor and secreted alpha-amyloid precursor protein

The expression and secretion of amyloid precursor protein (beta APP) is increased in rat cerebral cortices that have been denervated by subcortical lesions of the nucleus basalis of Meynert. The physiological role of the secreted beta APP in response to this injury has not been established. We have previously shown that secreted beta APP produced by alpha-secretase activity (sAPP(alpha)) potentiates the neuritogenic activity of nerve growth factor (NGF) in vitro on naive PC12 cells. In this investigation, we have further characterized the neurotrophic interaction of NGF and sAPP(alpha) using differentiated PC12 cells and rat primary cortical neurons. NGF required the expression of beta APP to maintain a neuronal phenotype. Reduction of endogenous beta APP expression by introduction of antisense oligonucleotides in the presence of NGF resulted in loss of neurites from differentiated PC12 cells but no apparent cell death. Addition of exogenous sAPP(alpha) (60--200 pM) potentiated the protective activity of NGF in serum-deprived differentiated PC12 cells as determined by retention of neurites and cell viability. In addition, exogenous sAPP(alpha) increased neuron viability in both short-term (3 days) cortical neuron cultures grown in the absence of serum and in long-term (9 days) cultures grown with serum. Disruption of the insulin signaling pathway by reduction of IRS-1 expression inhibited the ability of sAPP(alpha) to potentiate neurotrophic activity. These observations suggest that sAPP(alpha) acts as an injury-induced neurotrophic factor that interacts with NGF to enhance neuronal viability using the insulin signaling pathway.

Death of PC12 cells and hippocampal neurons induced by adenoviral-mediated FAD human amyloid precursor protein gene expression

We used adenoviral-mediated gene transfer of human amyloid precursor proteins (h-APPs) to evaluate the role of various h-APPs in causing neuronal cell death. We were able to infect PC12 cells with very high efficiency because approximately 90% of the cells were cytochemically positive for beta-galactosidase activity when an adenoviral vector containing LacZ cDNA was used to infect cells. Cells infected with adenovirus containing h-APP cDNA showed high-level transcription and expression of h-APP as measured by reverse transcriptase-polymerase chain reaction and Western immunoblot analyses, respectively. Intracellular and extracellular levels of h-APP were elevated approximately 17-and 24-fold in cultures infected with recombinant adenovirus containing wild-type mutant and 13- and 17-fold with V642F mutant. No elevation in h-APP was seen in cultures infected with antisense h-APP or null adenovirus. H-APP levels were maximal 3 days after infection. Overexpression of V642F mutant h-APP in PC12 cells and hippocampal neurons resulted in about a twofold increase in death compared with overexpression of wild-type h-APP. These results demonstrate the usefulness of recombinant adenoviral mediated gene transfer in cell culture studies and suggest that overexpression of a familial Alzheimer's disease mutant APP may be toxic to neuronal cells.

Effects of PS1 deficiency on membrane protein trafficking in neurons

We have examined the trafficking and metabolism of the beta-amyloid precursor protein (APP), an APP homolog (APLP1), and TrkB in neurons that lack PS1. We report that PS1-deficient neurons fail to secrete Abeta, and that the rate of appearance of soluble APP derivatives in the conditioned medium is increased. Remarkably, carboxyl-terminal fragments (CTFs) derived from APP and APLP1 accumulate in PS1-deficient neurons. Hence, PS1 plays a role in promoting intramembrane cleavage and/or degradation of membrane-bound CTFs. Moreover, the maturation of TrkB and BDNF-inducible TrkB autophosphorylation is severely compromised in neurons lacking PS1. We conclude that PS1 plays an essential role in modulating trafficking and metabolism of a selected set of membrane and secretory proteins in neurons.

Rapid ATP loss caused by methamphetamine in the mouse striatum: relationship between energy impairment and dopaminergic neurotoxicity

To study the relationship between energy impairment and the effects of d-methamphetamine (METH) on dopaminergic neurons, ATP and dopamine levels were measured in the brain of C57BL/6 mice treated with either a single or four injections of METH (10 mg/kg, i.p.) at 2-h intervals. Neither striatal ATP nor dopamine concentrations changed after a single injection of METH, but both were significantly decreased 1.5 h after the multiple-dose regimen. The effects of METH on ATP levels appear to be selective for the striatum, as ATP concentrations were not affected in the cerebellar cortex and hippocampus after either a single or multiple injections of METH. In a second set of experiments, an intraperitoneal injection of 2-deoxyglucose (2-DG; 1 g/kg), an inhibitor of glucose uptake and utilization, was given 30 min before the third and fourth injections of METH. 2-DG significantly potentiated METH-induced striatal ATP loss at 1.5 h and dopamine depletions at 1.5 h and 1 week. These results indicate that a toxic regimen of METH selectively causes striatal energy impairment and raise the possibility that perturbations of energy metabolism play a role in METH-induced dopaminergic neurotoxicity.

Chick sympathetic neurons in culture respond differentially to nerve growth factor and conditioned medium from activated splenic lymphocytes

Chicken splenic cells, stimulated by concanavalin A, secreted a factor or factors into the culture medium which supported the survival of neurons from sympathetic ganglia of chick embryos. The effect of this conditioned medium (CM) was similar to the effect of nerve growth factor (NGF). However, the enhanced survival effect of CM was unaffected by K-252a, a protein kinase inhibitor which completely abolished the effect of NGF. 6-Thioguanine, an inhibitor of NGF-activated protein kinase N, blocked the survival effects of both NGF and CM on sympathetic neurons, but a dose required for the half-maximal inhibition for the survival effect of CM was 10 times higher than that for NGF. H-7, an inhibitor of protein kinase C, did not block the effect of either CM or NGF. On the other hand, the survival effect of both CM and NGF was blocked to the same extent by 5'-deoxy-5'-methylthioadenosine and LiCl. These results suggest that activated splenic cells secreted neuronal survival-promoting factor(s) into CM and that the cellular mechanisms promoting neuronal survival by CM are different from those promoting neuronal survival induced by NGF.