Biogeographic patterns of meio- and micro-eukaryotic communities in dam-induced river-reservoir systems

Although the Three Gorges Dam (TGD) is the world's largest hydroelectric dam, little is known about the spatial-temporal patterns and community assembly mechanisms of meio- and micro-eukaryotes and its two subtaxa (zooplankton and zoobenthos). This knowledge gap is particularly evident across various habitats and during different water-level periods, primarily arising from the annual regular dam regulation. To address this inquiry, we employed mitochondrial cytochrome c oxidase I (COI) gene-based environmental DNA (eDNA) metabarcoding technology to systematically analyze the biogeographic pattern of the three communities within the Three Gorges Reservoir (TGR). Our findings reveal distinct spatiotemporal characteristics and complementary patterns in the distribution of meio- and micro-eukaryotes. The three communities showed similar biogeographic patterns and assembly processes. Notably, the diversity of these three taxa gradually decreased along the river. Their communities were less shaped by stochastic processes, which gradually decreased along the longitudinal riverine-transition-lacustrine gradient. Hence, deterministic factors, such as seasonality, environmental, and spatial variables, along with species interactions, likely play a pivotal role in shaping these communities. Environmental factors primarily drive seasonal variations in these communities, while hydrological conditions, represented as spatial distance, predominantly influence spatial variations. These three communities followed the distance-decay pattern. In winter, compared to summer, both the decay and species interrelationships are more pronounced. Taken together, this study offers fresh insights into the composition and diversity patterns of meio- and micro-eukaryotes at the spatial-temporal level. It also uncovers the mechanisms behind community assembly in various environmental niches within the dam-induced river-reservoir systems. KEY POINTS: • Distribution and diversity of meio- and micro-eukaryotes exhibit distinct spatiotemporal patterns in the TGR. • Contribution of stochastic processes in community assembly gradually decreases along the river. • Deterministic factors and species interactions shape meio- and micro-eukaryotic community.

Revolutionizing aquatic eco-environmental monitoring: Utilizing the RPA-Cas-FQ detection platform for zooplankton

The integration of recombinase polymerase amplification (RPA) with CRISPR/Cas technology has revolutionized molecular diagnostics and pathogen detection due to its unparalleled sensitivity and trans-cleavage ability. However, its potential in the ecological and environmental monitoring scenarios for aquatic ecosystems remains largely unexplored, particularly in accurate qualitative/quantitative detection, and its actual performance in handling complex real environmental samples. Using zooplankton as a model, we have successfully optimized the RPA-CRISPR/Cas12a fluorescence detection platform (RPA-Cas-FQ), providing several crucial "technical tips". Our findings indicate the sensitivity of CRISPR/Cas12a alone is 5 × 109 copies/reaction, which can be dramatically increased to 5 copies/reaction when combined with RPA. The optimized RPA-Cas-FQ enables reliable qualitative and semi-quantitative detection within 50 min, and exhibits a good linear relationship between fluorescence intensity and DNA concentration (R2 = 0.956-0.974***). Additionally, we developed a rapid and straightforward identification procedure for single zooplankton by incorporating heat-lysis and DNA-barcode techniques. We evaluated the platform's effectiveness using real environmental DNA (eDNA) samples from the Three Gorges Reservoir, confirming its practicality. The eDNA-RPA-Cas-FQ demonstrated strong consistency (Kappa = 0.43***) with eDNA-Metabarcoding in detecting species presence/absence in the reservoir. Furthermore, the two semi-quantitative eDNA quantification technologies showed a strong positive correlation (R2 = 0.58-0.87***). This platform also has the potential to monitor environmental pollutants by selecting appropriate indicator species. The novel insights and methodologies presented in this study represent a significant advancement in meeting the complex needs of aquatic ecosystem protection and monitoring.

Developmental Toxicity of PEDOT:PSS in Zebrafish: Effects on Morphology, Cardiac Function, and Intestinal Health

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a conductive polymer commonly used in various technological applications. However, its impact on aquatic ecosystems remains largely unexplored. In this study, we investigated the toxicity effects of PEDOT:PSS on zebrafish. We first determined the lethal concentration (LC50) of PEDOT:PSS in zebrafish and then exposed AB-type zebrafish embryos to different concentrations of PEDOT:PSS for 120 h. Our investigation elucidated the toxicity effects of zebrafish development, including morphological assessments, heart rate measurements, behavioral analysis, transcriptome profiling, and histopathological analysis. We discovered that PEDOT:PSS exhibited detrimental effects on the early developmental stages of zebrafish, exacerbating the oxidative stress level, suppressing zebrafish activity, impairing cardiac development, and causing intestinal cell damage. This study adds a new dimension to the developmental toxicity of PEDOT:PSS in zebrafish. Our findings contribute to our understanding of the ecological repercussions of PEDOT:PSS and highlight the importance of responsible development and application of novel materials in our rapidly evolving technological landscape.

Multi-omics reveal mechanisms underlying chronic kidney disease of unknown etiology (CKDu) pathogenesis using zebrafish

Chronic kidney disease of unknown etiology (CKDu) is an endemic disease in the dry zone of farming communities, Sri Lanka. The drinking water in a CKDu prevalent area contains a high concentration of F-, hardness and other environmental pollutants, including heavy metals and microcystin, which are considered possible etiology of CKDu in these areas. Here, multi-omics data with host transcriptome, metabolome and gut microbiomes were obtained using simulated local drinking water of Sri Lanka after their exposure to adult zebrafish. Based on an integrated multi-omics analysis in the context of host physiology in the kidney injury samples with different pathologic grades, two common pathways necroptosis and purine metabolism were identified as potentially important pathways that affect kidney injury. The key metabolite acetyl adenylate in the purine metabolism pathway was significantly positively correlated with Comamonas (rho = 0.72) and significantly negatively correlated with Plesiomonas (rho = -0.58). This crucial metabolite and two key gut bacteria genera may not only be potential markers but also potential therapeutic targets in the uric acid metabolic pathway, which is an important factor in the pathogenesis of acute kidney injury (AKI) in general, as well as of chronic kidney disease (CKD). Based on this, we revealed the urea metabolism pathway of kidney injury in zebrafish and provided a new avenue for the treatment of CKDu in Sri Lanka.

Supervised machine learning improves general applicability of eDNA metabarcoding for reservoir health monitoring

Effective and standardized monitoring methodologies are vital for successful reservoir restoration and management. Environmental DNA (eDNA) metabarcoding sequencing offers a promising alternative for biomonitoring and can overcome many limitations of traditional morphological bioassessment. Recent attempts have even shown that supervised machine learning (SML) can directly infer biotic indices (BI) from eDNA metabarcoding data, bypassing the cumbersome calculation process of BI regardless of the taxonomic assignment of eDNA sequences. However, questions surrounding the general applicability of this taxonomy-free approach to monitoring reservoir health remain unclear, including model stability, feature selection, algorithm choice, and multi-season biomonitoring. Here, we firstly developed a novel biological integrity index (Me-IBI) that integrates multitrophic interactions and environmental information, based on taxonomy-assigned eDNA metabarcoding data. The Me-IBI can better distinguish the actual health status of the Three Gorges Reservoir (TGR) than physicochemical assessments and have a clear response to human activity. Then, taking this reliable Me-IBI as a supervised label, we compared the impact of selecting different numbers of features and SML algorithms on the stability and predictive performance of the model for predicting ecological conditions in multiple seasons using taxonomy-free eDNA metabarcoding data. We discovered that even with a small number of features, different SML algorithms can establish a stable model and obtain excellent predictive performance. Finally, we proposed a four-step strategy for standardized routine biomonitoring using SML tools. Our study firstly explores the general applicability problem of the taxonomy-free eDNA-SML approach and establishes a solid foundation for the large-scale and standardized biomonitoring application.

Ultra-sensitive detection of ecologically rare fish from eDNA samples based on the RPA-CRISPR/Cas12a technology

Environmental DNA (eDNA) research holds great promise for improving biodiversity science and conservation efforts by enabling worldwide species censuses in near real-time. Current eDNA methods face challenges in detecting low-abundance ecologically important species. In this study, we used isothermal recombinase polymerase amplification (RPA)-CRISPR/Cas detection to test Ctenopharyngodon idella. RPA-CRISPR-Cas12a detected 6.0 eDNA copies/μL within 35 min. Ecologically rare species were identified in the Three Gorges Reservoir Area (TGRA) using functional distinctiveness and geographical restrictiveness, with seven fish species (9%) classified as potentially ecologically rare including three species in this investigation. RPA-CRISPR/Cas12a-FQ outperformed high-throughput sequencing (HTS) and qPCR in detecting low-abundance eDNA (AUC = 0.883∗∗). A significant linear correlation (R2 = 0.682∗∗) between RPA-CRISPR/Cas12a-FQ and HTS quantification suggests its potential for predicting species abundance and enhancing eDNA-based fish biodiversity monitoring. This study highlights the value of RPA-CRISPR/Cas12a-FQ as a tool for advancing eDNA research and conservation efforts.

[Population structure of food-borne Staphylococcus aureus in China]

Objective: To understand the population structure of food-borne Staphylococcus (S.) aureus in China. Methods: Whole genome sequencing was used to analyze 763 food-borne S. aureus strains from 16 provinces in China from 2006 to 2020. Multilocus sequence typing (MLST), staphylococcal protein A gene (spa) typing, and staphylococcal chromosome cassettemec (SCCmec) typing were conducted, and minimum spanning tree based on ST types (STs) was constructed by BioNumerics 7.5 software. Thirty-one S. aureus strains isolated from imported food products were also included in constructing the genome phylogenetic tree. Results: A total of 90 STs (20 novel types) and 160 spa types were detected in the 763 S. aureus isolates. The 72 STs (72/90, 80.0%) were related to 22 clone complexes. The predominant clone complexes were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, accounting for 82.44% (629/763) of the total. The STs and spa types in the predominant clone complexes changed over the years. The methicillin-resistant S. aureus (MRSA) detection rate was 7.60%, and 7 SCCmec types were identified. The ST59-t437-Ⅳa (17.24%, 10/58), ST239-t030-Ⅲ (12.07%, 7/58), ST59-t437-Ⅴb (8.62%, 5/58), ST338-t437-Ⅴb (6.90%, 4/58) and ST338-t441-Ⅴb (6.90%, 4/58) were the main types in MRSA strains. The genome phylogenetic tree had two clades, and the strains with the same CC, ST, and spa types clustered together. All CC7 methicillin sensitive S. aureus strains were included in Clade1, while 21 clone complexes and all MRSA strains were in Clade2. The MRSA strains clustered according to the SCCmec and STs. The strains from imported food products in CC398, CC7, CC30, CC12, and CC188 had far distances from Chinese strains in the tree. Conclusions: In this study, the predominant clone complexes of food-borne strains were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, which overlapped with the previously reported clone complexes of hospital and community-associated strains in China, suggesting that close attention needs to be paid to food, a vehicle of pathogen transmission in community and food poisoning.

Elucidating environmental factors and their combined effects on CKDu in Sri Lanka using zebrafish

Chronic kidney disease with uncertain etiology (CKDu) in Sri Lanka has attracted much attention as a global health issue. However, how environmental factors in local drinking water induce kidney damage in organisms is still elusive. We investigated multiple environmental factors including water hardness and fluoride (HF), heavy metals (HM), microcystin-LR (MC-LR), and their combined exposure (HFMM) to elucidate their toxic effects on CKDu risk in zebrafish. Acute exposure affected renal development and inhibited the fluorescence of Na, K-ATPase alpha1A4:GFP zebrafish kidney. Chronic exposure influenced the body weight of both genders of adult fish and induced kidney damage by histopathological analyses. Furthermore, the exposure significantly disturbed differential expression genes (DEGs), diversity and richness of gut microbiota, and critical metabolites related to renal functions. The transcriptomic analysis revealed that kidney-related DEGs were linked with renal cell carcinoma, proximal tubule bicarbonate reclamation, calcium signaling pathway, and HIF-1 signaling pathway. The significantly disrupted intestinal microbiota was closely related to the environmental factors and H&E score, which demonstrated the mechanisms of kidney risks. Notably, the Spearman correlation analysis indicated that the changed bacteria such as Pseudomonas, Paracoccus, and ZOR0006, etc were significantly connected to the DEGs and metabolites. Therefore, the assessment of multiple environmental factors provided new insights on "bio-markers" as potential therapies of the target signaling pathways, metabolites, and gut bacteria to monitor or protect residents from CKDu.

[Effect of health management service for hypertension patients under framework of Basic Public Health Service Project: a regression discontinuity design]

Objective: To evaluate the effect of health management service on hypertension patients (HMSFHP) under the framework of the Basic Public Health Service Project by using regression discontinuity design. Methods: The participants were enrolled from an observational cohort survey in 2015 and followed up was conducted in 2019. The participants with SBP 130-150 mmHg and/or DBP 80-100 mmHg in the baseline survey of the cohort in 2015 were included in the present study. Additionally, we obtained the dates of participants receiving HMSFHP and their blood pressure data from follow-up records, physical examination records and telephone interview. The participants were divided into intervention group and control group based on the cutoff points, i.e. SBP ≥140 mmHg and/or DBP ≥90 mmHg. The local linear regression model were used to estimate the effect of HMSFHP on reducing blood pressure of the participants. Results: After adjusting for age, sex and time length of receiving HMSFHP, the results of the model including participants with 80-100 mmHg for DBP in 2015 indicated that, for the participants who received HMSFHP, the DBP decreased by 6.66 mmHg from 2015 to 2019. For the participants with SBP 130-150 mmHg in 2015, the reduction estimate of the model was -6.17 mmHg, the difference was not significant (P=0.178), suggesting that receiving HMSFHP did not cause change in SBP for the participants who received HMSFHP. Conclusion: Receiving HMSFHP had effect to reduce DBP, and HMSFHP had a positive effect on the control of blood pressure in patients with hypertension.

[Prediction of superantigen active sites and clonal expression of staphylococcal enterotoxin-like W]

Objective: The docking and superantigen activity sites of staphylococcal enterotoxin-like W (SElW) and T cell receptor (TCR) were predicted, and its SElW was cloned, expressed and purified. Methods: AlphaFold was used to predict the 3D structure of SElW protein monomers, and the protein models were evaluated with the help of the SAVES online server from ERRAT, Ramachandran plot, and Verify_3D. The ZDOCK server simulates the docking conformation of SElW and TCR, and the amino acid sequences of SElW and other serotype enterotoxins were aligned. The primers were designed to amplify selw, and the fragment was recombined into the pMD18-T vector and sequenced. Then recombinant plasmid pMD18-T was digested with BamHⅠand Hind Ⅲ. The target fragment was recombined into the expression plasmid pET-28a(+). After identification of the recombinant plasmid, the protein expression was induced by isopropyl-beta-D- thiogalactopyranoside. The SElW expressed in the supernatant was purified by affinity chromatography and quantified by the BCA method. Results: The predicted three-dimensional structure showed that the SElW protein was composed of two domains, the amino-terminal and the carboxy-terminal. The amino-terminal domain was composed of 3 α-helices and 6 β-sheets, and the carboxy-terminal domain included 2 α-helices and 7 antiparallel β-sheets composition. The overall quality factor score of the SElW protein model was 98.08, with 93.24% of the amino acids having a Verify_3D score ≥0.2 and no amino acids located in disallowed regions. The docking conformation with the highest score (1 521.328) was selected as the analysis object, and the 19 hydrogen bonds between the corresponding amino acid residues of SElW and TCR were analyzed by PyMOL. Combined with sequence alignment and the published data, this study predicted and found five important superantigen active sites, namely Y18, N19, W55, C88, and C98. The highly purified soluble recombinant protein SElW was obtained with cloning, expression, and protein purification. Conclusions: The study found five superantigen active sites in SElW protein that need special attention and successfully constructed and expressed the SElW protein, which laid the foundation for further exploration of the immune recognition mechanism of SElW.

[Analysis on medical care seeking of local and non-local pulmonary tuberculosis patients reported in Beijing, 2016-2021]

Objective: To analyze the medical care seeking of local and non-local pulmonary tuberculosis (TB) patients in Beijing from 2016 to 2021 and provide evidence for TB prevention and control in Beijing. Methods: The reported pulmonary TB data from 2016 to 2021 were collected from tuberculosis management information system and standard code management system of Chinese information system for disease control and prevention. The map data were obtained from the Institute of Geographic Sciences and Natural Resources Research. Excel 2016, SPSS 19.0, Python 3.9 and ArcGIS 10.6 softwares were used for data analysis and visualization for the inter-provincial mobility and inter-district mobility of pulmonary TB patient's medical care seeking in Beijing. Results: Among the reported pulmonary TB patients in Beijing from 2016 to 2021, 35.27%(24 307/68 926) were from 30 provinces (autonomous regions, municipalities) and Xinjiang Production and Construction Corps. The top 5 provinces with pulmonary TB patients medical care seeking in Beijing were Hebei (39.58%,9 620/24 307), Shanxi (8.82%,2 145/24 307), Inner Mongolia Autonomous Region (8.66%,2 105/24 307), Heilongjiang (6.95%,1 690/24 307) and Henan (6.88%,1 672/24 307). Patients from these 5 provinces accounted for 70.89% (17 232/24 307) of total pulmonary TB patients from other provinces. The pulmonary TB patients from other provinces mainly flowed to Tongzhou district of Beijing, accounting for 46.72% (11 356/24 307). These pulmonary TB patients mainly visited grade Ⅲ (A) hospitals, such as Beijing Chest Hospital of Capital Medical University with the highest proportion of 44.76% (10 880/24 307). Among pulmonary TB patients with current residence in Beijing, those sought medical care in other districts accounted for 55.06% (24 566/44 619). The outflow and inflow of TB cases' medical care seeking occurred in 16 districts of Beijing. The median proportion of cross district medical care seeking in 16 districts was 59.30% (56.05%, 65.13%). The inflow of the medical care seeking in Tongzhou, Haidian and Xicheng district was greater than the outflow, and the outflow was greater than the inflow in the other 13 districts. The pulmonary TB patients in Beijing mainly went to Beijing Chest Hospital in Tongzhou for medical care seeking, accounting for 42.18%(18 822/44 619). Conclusions: The proportions of non-local pulmonary TB patients seeking medical care in Beijing from 2016 to 2021 and local pulmonary TB patients seeking medical care in other districts in Beijing were high, and the hospitals where non-local pulmonary TB patients and local pulmonary TB patients sought medical care respectively belonged to grade Ⅲ (A) and municipal designated medical institutions of TB.

Generation and application of a novel high-throughput detection based on RPA-CRISPR technique to sensitively monitor pathogenic microorganisms in the environment

Staphylococcus aureus (S. aureus) is an important opportunistic human and animal pathogen that can cause a wide diversity of infections. Due to its environmental health risks, it is crucial to establish a time-saving, high-throughput, and highly sensitive technique for water quality surveillance. In this study, we developed a novel method to detect S. aureus in the water environment based on recombinase polymerase amplification (RPA) and CRISPR/Cas12a. This method utilizes isothermal amplification of nucleic acids and the trans-cleavage activity of the CRISPR/Cas12a system to generate fluorescence signals with a single-stranded DNA-fluorophore-quencher (ssDNA-FQ) reporter and a naked-eye detected lateral flow assay (LFA). Our RPA-CRISPR/Cas12a detection system can reduce the detection time to 35 min and enhance the high-throughput detection threshold to ≥5 copies of pathogen DNA, which is more sensitive than that of reported. Moreover, in the lower reaches of the Jialing River in Chongqing, China, 10 water samples from the mainstream and 7 ones from tributaries were successfully monitored S. aureus for less than 35 min using RPA-CRISPR/Cas12a detection system. Taken together, a novel high-throughput RPA-CRISPR detection was established and firstly applied for sensitively monitoring S. aureus in the natural water environment.

[Marsili syndrome manifested by fever: a case report and literature review]

Objective: To describe the clinical features, genetic characteristics, and diagnosis of Marsili syndrome, an extremely rare disease which should be differentiated from other fever disorders. Methods: The clinical data and diagnostic process of a case with Marsili syndrome, hospitalized in the Department of Respiratory and Critical Care Medicine, the Eighth Medical Center of Chinese PLA General Hospital in February 2021, were summarized. The exon regions of 20, 000 genes of peripheral blood were detected in the patient and her parents. Using key words of"Marsili syndrome"and"ZFHX2 gene mutation", the related literatures were searched in Wanfang and PubMed databases from January, 2000 to November, 2021. In addition, the literatures of congenital insensitivity to pain and anhidrosis were retrieved in Wanfang domestic database from the same period. Results: A 23-year-old female patient had suffered from recurrent fever for more than two years, accompanied by anhidrosis, insensitive to pain and weakened corneal reflex. The effect of non-steroidal anti-inflammatory drugs for fever was minimal. The ZFHX2 gene mutation was positive in the patient and her mother, while NTRK1 gene mutation specific to congenital insensitivity to pain with anhidrosis (CIPA) was negative. The ZFHX2 gene mutation was negative in her father. A total of 2 literatures of Marsili syndrome were retrieved and a total of 6 cases of Marsili syndrome in one family were reported worldwide up to now. These patients had a group of similar symptoms including fever, little or no sweating, and insensitivity to pain caused by skin burn and bone fracture. However, there was no abnormality in headache and visceral pain, and female patients' childbirth pain as well as tactile sensation in these cases. The corneal reflex was decreased or negative. They had less sensitivity to stimulus of capsaicin. The ZFHX2 gene mutation was positive, but NTRK1 gene was not detected in all patients. A total of 4 literatures were retrieved and a total of 34 cases of CIPA were reported in China. Though Marsili syndrome and CIPA exhibited a number of similar clinical manifestations, they were distinct diseases and had obviously different outcome. Conclusions: Marsili syndrome is an autosomal dominant genetic disease. It is extremely rare worldwide. In clinical practice, when a patient presents with unexplained recurrent fever and poor effect of non-steroidal anti-inflammatory drugs, especially with the symptoms of no sweating and insensitivity to pain, the possibility of Marsili syndrome should be considered and the ZFHX2 gene should be determined. Marsili syndrome appears to be a benign disease with a good prognosis. A definitive diagnosis can avoid ineffective treatment and its adverse effects. To our knowledge, there is currently no effective genetic therapy for this disease.

[Preliminary study on smoking-related behaviors of people aged 60 and over suffering from respiratory diseases in Shangqiu area]

The purpose of this study is to explore the smoking-related behaviors of people ≥60 years of age with respiratory diseases in Shangqiu area. A total of 550 patients with respiratory diseases ≥60 years old who were treated at the First People's Hospital of Shangqiu from April 2015 to April 2017 were selected as the survey subjects through random sampling. Among them, there were 351 males and 199 females; the age ranged from 60 to 86 (72.85±5.71) years old. Follow-up until April 2020, and the follow-up was 3 years or more and related information and death information were also collected. The multivariate Cox proportional hazard regression model was used to analyze the influence of smoking behavior in the survey subjects on the death risk of people with respiratory diseases ≥ 60 years old. A total of 550 cases were included in the survey, and 25 cases were lost to follow-up. The effective number was 525, and the survey effective rate was 95.45%. Among the 525 patients, 336 (64.00%) were males and 189 (36.00%) were females. The age ranged from 60 to 86 (72.69±5.64) years old. The education level was mainly high school and technical secondary school, accounting for 39.24% of the total population. The primary diseases included tracheitis/bronchitis, asthma, pneumonia, COPD and lung cancer. Among 525 patients with respiratory diseases ≥60 years old, non-smokers accounted for 11.05% (58/525), smokers accounted for 68.00% (357/525), and quitters accounted for 20.95% (110/525). The duration of smoking was more than 20 years, accounting for 33.33% (175/525). The smoking intensity was mainly moderate, accounting for 33.90% (178/525). The duration of smoking cessation was mainly<5 years, accounting for 8.76% (46/525). Follow-up until April 2020, the mortality rate of 525 patients with respiratory diseases ≥60 years old was 14.10% (74/525). Cox regression analysis showed that smoking duration, smoking intensity, cumulative smoking amount, and duration of smoking cessation were the influencing factors of death in patients with respiratory diseases ≥60 years old in Shangqiu area (P<0.05). It can be seen that smoking duration, smoking intensity, cumulative smoking amount, and smoking cessation duration may be independent risk factors for death in patients with respiratory diseases ≥ 60 years old in Shangqiu area, and may increase the relative risk of death.

Role of manganese superoxide dismutase (Mn-SOD) against Cr(III)-induced toxicity in bacteria

The toxicity of Cr(VI) was widely investigated, but the defense mechanism against Cr(III) in bacteria are seldom reported. Here, we found that Cr(III) inhibited bacterial growth and induced reactive oxygen species (ROS). After exposure to Cr(III), loss of sodA not only led to the excessive generation of ROS, but also enhanced the level of lipid peroxidation and reduced the GSH level, indicating that the deficiency of Mn-SOD decreased the bacterial resistance ability against Cr(III). The adverse effects of oxidative stress caused by Cr(III) could be recovered by the rescue of Mn-SOD in the sodA-deficient strain. Besides the oxidative stress, Cr(III) could cause the bacterial morphology variation, which was distinct between the wild-type and the sodA-deficient strains due to the differential expressions of Z-ring division genes. Moreover, Mn-SOD might prevent Cr(III) from oxidation on the bacterial surface by combining with Cr(III). Taken together, our results indicated that the Mn-SOD played a vital role in regulating the stress resistance, expression of cell division-related genes, bacterial morphology, and chemistry valence state of Cr. Our findings firstly provided a more in-depth understanding of Cr(III) toxicity and bacterial defense mechanism against Cr(III).

[The application of next-generation sequencing in the diagnosis of Pneumocystis pneumonia in non-HIV infected patients]

Objective: To evaluate the clinical value of next-generation sequencing in the diagnosis of Pneumocystis pneumonia in non-HIV infected patients. Methods: A retrospective study was conducted on the diagnosis and treatment of Pneumocystis pneumonia in 5 non-HIV patients in the Fourth Medical Center of the General Hospital of the PLA from September 1, 2017 to September 1, 2018. Next-generation sequencing of BALF were compared with the traditional laboratory microbiological test, and the advantages of the next-generation sequencing in the diagnosis of Pneumocystis pneumonia in non-HIV infected patients were analyzed. Results: There were 3 males and 2 females, with a mean age (48±6) years. Three patients had membranous nephropathy, a patient had tuberculous meningitis, and a patient had esophageal cancer after radiotherapy and chemotherapy. All patients had glucocorticoid medication history before. The clinical manifestations were fever, cough and dyspnea. The chest CT mainly showed bilateral lung ground glass shadows. All the results of 1, 3-β-D-glucan test were more than 1 000 ng/L. Bronchoalveolar lavage was performed in the 5 cases, and Pneumocystis cysts were found in 1 BALF by Gomori's methenamine silver nitrate staining, and the DNAs of Pneumocystis and human herpesvirus were detected in 5 BALFs by next-generation sequencing. All patients were treated with sulfamethoxazole/trimethoprim (orally, 1.44 g, q8 h) for 23 to 72 days (median 33 days), and with ganciclovir(Ⅳ, 250 mg q12 h) for 6 to 22 days (median 15 days). The chest CT manifestations and symptoms were improved after treatment, without death. Conclusions: The next-generation sequencing of BALF is more specific and sensitive in the diagnosis of Pneumocystis pneumoniae in non-HIV patients. It is faster, more comprehensive and more accurate than the traditional laboratory test, and could be widely used as a PCP diagnosis technique.

[Tap-hammer elicited vestibular-evoked myogenic potentials system: its design and preliminary application]

Objective: The aim of this study was to design and perform "Tap-hammer"system that can be used to elicit vestibular evoked myogenic potentials (VEMP) in normal adults and to report the preliminary results of this system. Methods: A triggered Tap-hammer was designed, made and connected with an electric recording system, to form as a system for Tap-VEMP recording. Twenty healthy adult volunteers (7 males and 13 females, aged 20 to 37 years, 40 ears in total) were recruited for air-conducted sound VEMP (ACS-VEMP) and Tap-VEMP examinations. Waveforms and parameters of both VEMPs were recorded and analyzed. SPSS 22.0 software was used for statistical analysis. Results: The response rates of ACS-, Tap-ocular VEMP (oVEMP) and ACS-, Tap-cervical VEMP (cVEMP) were both 100% (40/40). The mean±SD n1 latency, p1 latency, n1-p1 interval, amplitude, and asymmetry ratio (AR%) of Tap-oVEMP were (9.80±2.51)ms, (13.90±3.26)ms, (4.09±1.43)ms, (16.43±9.61)μV, (22.68±17.35)% respectively. The mean±SD p1 latency, n1 latency, p1-n1 interval, amplitude, and asymmetry ratio (AR%) of Tap-cVEMP were (13.26±2.07)ms, (21.84±2.89)ms, (8.58±2.10)ms, (457.65±274.94)μV, (20.42±13.46)% respectively. Both n1 latency and p1 latency of Tap-VEMPs were shorter than those in ACS-VEMPs (P<0.05). No statistical difference could be found between the two stimulation methods in the parameters of n1-p1 interval, amplitude, and asymmetry ratio(P>0.05). Conclusion: The Tap-hammer system can elicit VEMP responses in healthy young people. This system can be used as an alternative stimulation method for bone conduction VEMP.

[Related factors for microalbuminuria in adult type 1 diabetes patients of short disease duration]

Objective: To investigate related factors for microalbuminuria in adult type 1 diabetes (T1D) patients of short disease duration (less than 5 years), and provide evidence for prevention of early diabetic kidney disease in this population. Methods: All adult patients enrolled in the Guangdong T1D translational medicine study between 2011 and 2017 with a disease duration of less than 5 years were included in this analysis. At enrollment, patients' demographic and clinical data were documented, and blood and urine samples were collected for the measurements of blood lipids, glycated hemoglobin A1c and urine albuminuria. Insulin resistance was evaluated by estimated glucose disposal rate (eGDR). Patients were categorized into groups based on urine albumin creatitine ratio (UACR): normoalbuminuric group (UACR<30 mg/g) and microalbuminuric group (UACR≥30 mg/g). Stepwise multivariate linear regression analysis was used to analyze risk factors for microalbuminuria in adult T1D patients of short disease duration. Results: A total of 384 patients were included in this analysis, and 51.3% (197/384) of which was female. The onset age of patients was (24.6±12.5) years, with a disease duration of 2.1(0.6, 3.5) years, body mass index of (19.8±3.2) kg/m(2), waist hip ratio of 0.85±0.21, and glycated hemoglobin A1c of (9.8±3.3)% at enrollment. Microalbuminuria occurred in 62 patients (16.1%). Multivariate linear analysis showed that higher glycated hemoglobin A1c, higher systolic blood pressure and more severe insulin resistance were related factors for microalbuminuria (t=2.322, 2.868 and -2.373, respectively, all P<0.05). Conclusions: Microalbuminuria was not rare in adult T1D patients of short disease duration. Inadequate glycemic control and insulin resistance were independent related factors for microalbuminuria in this population.

[Evaluation of vestibular evoked myogenic potential, caloric test and cochlear electrogram in the diagnosis of Meniere's disease]

Objective:The aim of this study is to evaluate the diagnostic value of vestibular-evoked myogenic potential （cVEMP and oVEMP）, caloric test, and cochlear electrogram （EcochG） in patients with Meniere's disease （MD） and non-Meniere's disease. Method:Sixty-four patients （64 ears） with Unilateral Meniere's disease were enrolled in the study group （MD group）, and 127 cases（254 ears） of non-Meniere's disease patients as non-MD group, including vertigo migraine in 40 cases, benign paroxysmal positional vertigo in 48 cases, benign recurrent vertigo in 13 cases, vestibular paroxysmia in 3 cases, vestibular neuritis in 5 cases and other undiagnosed vertigo in 18 cases. Both group undertake cVEMP, oVEMP, caloric test and ECochG. Use Medcale software to draw ROC curve of ECochG and calculate the area under curve（AUC）, Jordan index and optimal diagnostic cut-off points. Make the cut-off point as the point of -SP/AP, then evaluate the sensitivity, specificity, positive predictive value（PPV）, negative predictive value（NPV） and diagnostic accuracy of cVEMP, oVEMP, caloric test and ECochG in MD group and non-MD group. Result:The AUC of ECochG ROC curve was 0.74, the Jordan index was 0.47 and the cut-off point was 0.4. The sensitivity and specificity of cVEMP（62% and 68%）, oVEMP（61% and 53%） and caloric test（53% and 57%） were all below ECochG（65% and 78%）. The positive predictive value and of ECochG was the highest（61.9%）, the negative predictive value of cVEMP was highest（87.5%）. The diagnostic accuracy of ECochG was highest（74%）, followed with cVEMP（67%）, oVEMP（55%） and caloric test（56%）. Conclusion:Compared with the vestibular function tests, the sensitivity, specificity, diagnostic accuracy and NPV were all higher in ECochG, and the diagnostic benefit can be maximized when -SP/AP value>0.4. So the value of single vestibular function examination in the diagnosis of Meniere's disease is limited. The diagnosis of MD still requires a comprehensive evaluation in combination with medical history, audiological tests and vestibular function examinations.

[Awareness of preconceptional care and its related factors in women of child-bearing age with type 1 diabetes]

Objective: To investigate the awareness of preconception care among women of child-bearing age with type 1 diabetes (T1DM) and their self-management status, in order to provide evidence for establishment of management pathway for women with T1DM in pregnancy in China. Methods: This cross-sectional survey recruited female participants of child-bearing age from the cohort of Guangdong Type 1 Diabetes Translational Medicine Study conducted between June 2011 and December 2017. The participants were asked to fill out a questionnaire on the awareness of preconception care, their frequency of self-monitoring of blood glucose (SMBG) and other related variables. Chi-squared test or chi-squared test for trend was used in comparisons of categorical variables, and logistic regression analysis was performed to assess associated factors. Results: Totally, 441 women of child-bearing age with T1DM were investigated. The results show that their awareness of preconception care was poor (15.42%, 68/441). Higher educational level (χ(2trend)=3.990, P=0.046), experience of post-diabetes education evaluation (P<0.001), and better coverage of different modules in diabetes education (survival skills: χ(2)=7.525, P=0.004; basic knowledge: χ(2)=8.598, P=0.002; advanced knowledge: P<0.001) were associated with better awareness of preconception care. The average frequency of SMBG in these participants was 0.29 (0.14, 2.00) times per day, and only 8.5% (37/435) of them reached the frequency (≥4 times per day) recommended by guidelines. Moreover, 21.1% (92/435) of them hardly ever performed SMBG. Conclusion: Child-bearing age women with T1DM in Gunangdong had poor awareness of preconception care, with a much lower SMBG frequency than recommendation.

[Blood pressure changes in 18-59 years old adults in rural area of Shanxi province, China]

Objective: To analyze the blood pressure changes of adults aged 18-59 years in rural area of Shanxi province based on a cohort study, and provide reference for the study of the blood pressure level of rural residents and hypertension prevention and control in rural areas in China. Methods: Data were obtained from Shanxi Nutrition and Chronic Disease Family Cohort from 2002 to 2015. Subjects aged <18 years or ≥60 years and individuals with hypertension at baseline survey in 2002, and those who had taken antihypertensive drugs for nearly two weeks during the follow-up survey in 2015 were excluded from the study. A total of 1 629 subjects aged 18-59 years were included in the analyses of the blood pressure level and its change from the baseline survey in 2002 to follow-up survey in 2015. Results: The systolic blood pressure (SBP) of the subjects increased from (122.7±10.4) mmHg in 2002 to (132.8±17.6) mmHg in 2015 and the diastolic pressure (DBP) increased from (72.7±6.9) mmHg in 2002 to (78.8±10.3) mmHg in 2015. The SBP in men and women increased with growth rates of 6.7% and 9.5%. While DBP in men and women increased with growth rates of 9.3% and 7.8%. The SBP levels of those aged 18-, 30-, 40- and 50-59 years increased with growth rates of 5.0%, 6.7%, 9.4% and 11.8%. While the DBP of these age groups increased with growth rates of 12.2%, 8.2%, 8.2% and 6.5%. Conclusions: The blood pressure of adults aged 18-59 years old in rural area of Shanxi showed a substantially increasing trend. The mean increase level of SBP in women was higher than that in men, and increased with age. While the mean increase level of DBP in men is higher than that in women, and decreased with age.

[Preliminary observation of galvanic vestibular stimulation-vestibular evoked myogenic potentials in healthy young people]

Objective: To introduce the method of galvanic vestibular stimulation-vestibular evoked myogenic potentials (GVS-VEMP) as well as to observe and analyze the parameters and elicited rate of GVS-cVEMP and GVS-oVEMP in healthy young people in China. Methods: Twenty six normal young subjects were recruited for conventional examinations of GVS-VEMP. The subjects were 21-37 years old, average age was (25.8±3.7) years old, including 13 males and 13 females. The galvanic stimulation intensity of 3 mA/1 ms was used to evoke cVEMP and oVEMP on the sternocleidomastoid and inferior extraocular muscles respectively, and the intensity of stimulus was decreased until the response disappeared, the threshold, latency, amplitude, interval phase and interaural amplitude ratio(IAR) were calculated. SPSS18.0 software was used for statistical analysis. Results: All subjects were elicited normal GVS-cVEMP and GVS-oVEMP under 3 mA/1 ms, the elicited rate was 100%. The threshold of GVS-cVEMP was (1.18±0.47) mA, p1 latency was (10.43±1.54) ms, n1 latency was (17.91±1.20) ms, the amplitude was (102.47±56.77) uV and IAR was (0.26±0.20). The threshold of GVS-oVEMP was (1.12±0.50) mA, n1 latency was (8.46±1.05) ms, p1 latency was (11.83±1.27) ms, the amplitude was (9.12±6.82) uV and IAR was (0.25±0.20). In terms of gender and lateral comparison, only the GVS-oVEMP amplitude was higher for male than for female, which had significant statistical difference (P<0.05), and there was no statistical difference in the other parameters between GVS-cVEMP and GVS-oVEMP. Conclusion: GVS-cVEMP and GVS-oVEMP could be elicited in healthy youth population, and the parameters could provide reference for subsequent vestibular function evaluation.

[Functional vestibulo-ocular reflex test]

Summary In recent years, the diagnosis and treatment of vertigo and balance disorders have become a hot topic of multidisciplinary attention. The evaluation method of vestibular function has also been improved, providing important evidence for the diagnosis and differential diagnosis of vertigo related diseases. Vestibular rehabilitation is one of the important methods for the treatment of vertigo diseases. Assessing vestibular rehabilitation status in these patients is also the key for guiding treatment. The assessment of vestibulo-ocular reflex (VOR) function is an important part of vestibular functional testing. Currently, the dynamic visual acuity test (DVAT), gaze stabilization test (GST), and head impulse test (HIT) can be used to evaluate the VOR function. Based on these tests, a method of vestibular function testing has emerged internationally: functional head impulse test (fHIT). The article based on the review of relevant literatures and the principle of VOR detection and HIT detection to introduce the test methods and results interpretation of fHIT, DVAT and GST to provide reference for clinical diagnosis and treatment.

[Clinical diagnosis and treatment of eosinophilic otitis media]

Objective: Eosinophilic otitis media(EOM) is a rare,refractory otitis media.This article summarizes the clinical manifestations and diagnosis and treatment experience of EOM. Method: Retrospective analysis of 3 cases of EOM patients with medical history, clinical manifestations, and related auxiliary examinations.Discuss the EOM clinical features,diagnosis and treatment in conjunction with the literature. Result: The clinical features of 3 patients with EOM were summarized as: a large amount of yellowish white secretions or polyps formation, obvious itching symptoms; polyp biopsy showed a large amount of eosinophil infiltration;topical use of hormone-containing ear drops treatment is effective.Conclusion: EOM is a new type of chronic otitis media.It has characteristic clinical manifestations,a comprehensive treatment based on glucocorticoids should be given..

[Suppression head impulse paradigm in healthy adult population: the values and features of the parameters]

Objective: To observe the parameters of the results of suppression head impulse paradigm (SHIMP) in healthy adults, and to provide reference for evaluating vestibular oculomotor reflex function in patients with peripheral vertigo. Methods: Fifty healthy adults, 22 males and 28 females, aged from 23-65 years, with an average age of (38.5±11.6) years, were recruited from January to March 2018. Parameters provided by the video head pulse software included the gains, the latency and the peak velocity of saccades, and comparison was made with head impulse paradigm (HIMP). Results: All subjects were elicited anti-compensatory saccades in SHIMP. The normal values of left and right gains were 1.02 and 1.10 in HIMP, and 0.93 and 1.01 in SHIMP respectively. The left and right saccades latency were (201.1± 50.8)ms and (187.0± 42.9)ms, and the peak saccadic velocity were (302.7±58.5)°/s and (291.5±46.5)°/s in SHIMP; there were small but significant difference between two sides about gains in HIMP and SHIMP, as well as latency in SHIMP(P<0.05); there were small but significant difference between HIMP and SHIMP about gains in ipsilateral(P<0.01); there were no significant difference between two sides about peak saccadic velocity in SHIMP(P>0.05). Conclusions: SHIMP can be used for the examination of vestibular oculomotor reflex function in adult population. It is easy to be operated and is convenient for clinical application. Combined with head pulse test, the function of the semicircular canal can be evaluated together.

[Perioperative management of pregnant women combined with congenital fibrinogen deficiency: four cases report and literature review]

Congenital fibrinogen deficiency is an autosomal recessive or dominant disorder in which quantitative (afibrinogenaemia or hypofibrinogenaemia) or qualitative (dysfibrinogenaemia) defects in the fibrinogen Aa, Bb or c protein chains that lead to reduced functional fibrinogen. We now report the perioperative management of 4 pregnant women suffering from hypofibrinogenaemia scheduled for elective caesarean section from December 2012 to October 2016 in Peking University First Hospital and review this disease with reference to classification, symptom, replacement therapy, and selection of the modes of pregnancy termination and anesthesia. The four patients were all asymptomatic, whereas there existed recurrent pregnancy loss (case 3), family history (case 2), and offspring heredity (cases 3 and 4). Routine clotting studies revealed low fibrinogen levels and prolonged thrombin time (TT) during pregnancy and on admission. However, the platelet (PLT) count, prothrombin time (PT) and activated partial thromboplastin time (APTT) were normal. All the patients were administered fibrinogen concentrate perioperatively, and underwent uncomplicated combined spinal-epidural anesthesia and uneventful surgical procedure without postpartum hemorrhage. The replacement therapy of fibrinogen or fresh frozen plasma administration was essential to avoid anesthesia and obstetric complications. Regional blockade could safely be offered in the caesarean section, providing that their coagulation defect was corrected by availability of therapeutic products and adequate response to treatment. In addition, the point-of-care rotational thrombelastometry (ROTEM) or thrombelastogram (TEG) could play an important role in an optimal perioperative management for such patients. Management plans must be tailored to each individual, taking into consideration their bleeding risk as well as potential maternal and neonatal complications.

[Vestibular-evoked myogenic potentials in healthy guinea pigs]

Objective:To establish detection methods of air-conducted sound elicited vestibular-evoked myogenic potentials (ACS-VEMPs) in guinea pigs, including cervical vstibular-evoked myogenic potential (cVEMP) and ocular vestibular evoked myogenic potential (oVEMP). Method:Eleven healthy (250-350 g) guinea pigs (22 ears) were selected and underwent conventional ACS-cVEMP and ACS-oVEMP examinations. Parameters of waveforms were recorded. Result:The ACS-cVEMP and ACS-oVEMP could be elicited in 77.27% and 59.09% guinea pigs,respectively；threshold was (107.1±14.6)dB SPL and (115.5±15.6)dB SPL for ACS-cVEMP and ACS-oVEMP；n1,p1 latency for cVEMP was (7.4±1.5)ms and (9.3±1.6)ms，(6.4±1.4)ms and (8.1±1.8)ms for oVEMP；amlipude was (15.4±8.6)μV and (11.4±6.0)μV for cVEMP and oVEMP respectively. No statistical difference could be found in above parameters between ACS-cVEMP and ACS-oVEMP (P>0.05). Conclusion:Both ACS-cVEMP and ACS-oVEMP could be elicited in guinea pigs.

Non-Dirac Chern insulators with large band gaps and spin-polarized edge states

Based on first-principles calculations and k·p models, we demonstrate that PbC/MnSe heterostructures are a non-Dirac type of Chern insulator with very large band gaps (244 meV) and exotically half-metallic edge states, providing the possibilities of realizing very robust, completely spin polarized, and dissipationless spintronic devices from the heterostructures. The achieved extraordinarily large nontrivial band gap can be ascribed to the contribution of the non-Dirac type electrons (composed of px and py) and the very strong atomic spin-orbit coupling (SOC) interaction of the heavy Pb element in the system. Surprisingly, the band structures are found to be sensitive to the different exchange and correlation functionals adopted in the first-principles calculations. Chern insulators with various mechanisms are acquired from them. These discoveries show that the predicted nontrivial topology in PbC/MnSe heterostructures is robust and can be observed in experiments at high temperatures. The system has great potential to have attractive applications in future spintronics.

[Comparison of the safety of two treatment methods of cesarean scar pregnancy of typeⅡ and Ⅲ in menopause within 7 weeks]

Objective: To comparison of the safety of two treatment methods of cesarean scar pregnancy (CSP) of typeⅡ and Ⅲ in menopause within 7 weeks. Methods: Totally 70 cases of CSP of typeⅡ and Ⅲ within 7 weeks of the last menstrual period, hospitalized within Peking University First Hospital from January 2009 to May 2016, had been retrospectively studied in two groups of different treatments. The methotrexate (MTX) treatment group included 37 cases receiving ultrasound-guided complete curettage of uterine cavity combined with MTX therapy, while the uterine artery embolization (UAE) group had 33 cases treated with UAE combined with MTX therapy and subsequent ultrasound-guided complete curettage of uterine cavity. The bleeding measurements during operation had been documented and compared for the study. Results: The comparative difference of bleeding measurements between the MTX treatment group and the UAE group was insignificant from the statistical perspective (median: 5.0 vs 5.0 ml, P=0.716).The comparative difference of the duration (median: 2.0 vs 6.0 days, P<0.01) and expenses (median: 2 832.1 vs 10 147.1 yuan, P<0.01) for hospitalization between the MTX treatment group and the UAE group were significant from the statistical perspective. Conclusions: The bleeding risks may not increase during the treatment of ultrasound-guided complete curettage of uterine cavity combined with MTX therapy for CSP patients of type Ⅱ and Ⅲwithin 7 weeks of the last menstrual period. Meanwhile, the UAE adverse effects and complications will be avoided, and the duration and expenses for hospitalization will be reduced.

Management of Valsa Canker on Apple with Adjustments to Potassium Nutrition

Valsa canker, caused by the fungus Valsa mali, is one of the most destructive diseases of apple in the primary production areas of China and other East Asian countries. Currently, there are no effective control methods for this disease. We investigated the occurrence of Valsa canker in 24 apple orchards in Shaanxi Province in concert with foliar nutrient analysis, and found that there was a significant negative correlation of leaf potassium (K) content with incidence and severity of Valsa canker. Fertilization experiments showed that increasing tree K content enhanced resistance to pathogen colonization and establishment. Apple trees with leaf K content greater than 1.30% exhibited almost complete resistance to Valsa mali. Field trials demonstrated that increasing K fertilization could significantly reduce disease incidence. Improved management of tree nutrition, especially K content, could effectively control the occurrence and development of Valsa canker.

Effects of propofol on lipopolysaccharide-induced expression and release of HMGB1 in macrophages

This study aimed to determine the effects of different concentrations of propofol (2,6-diisopropylphenol) on lipopolysaccharide (LPS)-induced expression and release of high-mobility group box 1 protein (HMGB1) in mouse macrophages. Mouse macrophage cell line RAW264.7 cells were randomly divided into 5 treatment groups. Expression levels of HMGB1 mRNA were detected using RT-PCR, and cell culture supernatant HMGB1 protein levels were detected using enzyme-linked immunosorbent assay (ELISA). Translocation of HMGB1 from the nucleus to the cytoplasm in macrophages was observed by Western blotting and activity of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in the nucleus was detected using ELISA. HMGB1 mRNA expression levels increased significantly in the cell culture supernatant and in cells after 24 h of stimulating RAW264.7 cells with LPS (500 ng/mL). However, HMGB1 mRNA expression levels in the P2 and P3 groups, which received 500 ng/mL LPS with 25 or 50 μmol/mL propofol, respectively, were significantly lower than those in the group receiving LPS stimulation (P<0.05). After stimulation by LPS, HMGB1 protein levels were reduced significantly in the nucleus but were increased in the cytoplasm (P<0.05). Simultaneously, the activity of NF-κB was enhanced significantly (P<0.05). After propofol intervention, HMGB1 translocation from the nucleus to the cytoplasm and NF-κB activity were inhibited significantly (each P<0.05). Thus, propofol can inhibit the LPS-induced expression and release of HMGB1 by inhibiting HMGB1 translocation and NF-κB activity in RAW264.7 cells, suggesting propofol may be protective in patients with sepsis.

Effect of hypertonic sodium chloride hydroxyethyl starch 40 on ET, TXB2, 6-keto-PGF1α, and ANP of preeclampsia in caesarean section

OBJECTIVE

Preeclampsia is a unique disease of pregnancy. Delivery via caesarean section is the most important way of terminating the pregnancy and treating preeclampsia. Perioperative fluid therapy is performed to maintain the circulatory volume and reduce tissue edema. This study evaluated the effects of hypertonic sodium chloride hydroxyethyl starch 40 (HSH40) as perioperative fluid therapy for preeclampsia patients.

MATERIALS AND METHODS

Forty preeclamptic women were randomly divided into two groups: the Ringer's solution group and the HSH40 group. Their ECG, HR, MAP, and SPO2 were monitored. Their MVP and HR were recorded at five, eight, and ten minutes after anesthesia induction and at the end of the caesarean section. The corresponding volume of infusion, blood loss, and urine output during the operation were also recorded. Venous samples were collected before HSH40 infusion and 30 min after infusion to measure the plasma concentrations of ET, TXB2, 6-keto-PGF1α, and ANP via a radioimmunoassay.

RESULTS

HSH40 infusion significantly decreased the plasma ET levels (p < 0.01), significantly changed the plasma ANP and TXB2 levels (p < 0.05), and significantly increased the plasma 6-keto-PGF1α levels (p < 0.01) in the experimental group compared with those before infusion. The plasma levels of ET, ANP, TXB2, and 6-keto-PGF1α did not significantly change in the control group. Compared with T1, MAP decreased significantly at T2, T3, T4, and T5 within groups (p < 0.05) and between the two groups. MAP significantly changed at T2, T3, T4, and T5 (p < 0.05). HR did not significant change at T1, T2, T3, T4, and T5 within or between groups. Volume of infusion and urine volume significantly differed between groups (p < 0.05).

CONCLUSION

Low-dose HSH40 lowers the plasma levels of vasoconstrictor substances (ET and TXB2) and increases the levels of vasodilator substances (6-keto-PGF1α and ANP) during preeclampsia. It effectively maintains and stabilizes the circulating blood volume, increasing renal blood flow, which improves renal function and increases urine output.

Antibiotic resistance of lactic acid bacteria isolated from Chinese yogurts

The aim of this study was to evaluate the susceptibility of 43 strains of lactic acid bacteria, isolated from Chinese yogurts made in different geographical areas, to 11 antibiotics (ampicillin, penicillin G, roxithromycin, chloramphenicol, tetracycline, chlortetracycline, lincomycin, kanamycin, streptomycin, neomycin, and gentamycin). The 43 isolates (18 Lactobacillus bulgaricus and 25 Streptococcus thermophilus) were identified at species level and were typed by random amplified polymorphic DNA analysis. Thirty-five genotypically different strains were detected and their antimicrobial resistance to 11 antibiotics was determined using the agar dilution method. Widespread resistance to ampicillin, chloramphenicol, chlortetracycline, tetracyclines, lincomycin, streptomycin, neomycin, and gentamycin was found among the 35 strains tested. All of the Strep. thermophilus strains tested were susceptible to penicillin G and roxithromycin, whereas 23.5 and 64.7% of Lb. bulgaricus strains, respectively, were resistant. All of the Strep. thermophilus and Lb. bulgaricus strains were found to be resistant to kanamycin. The presence of the corresponding resistance genes in the resistant isolates was investigated through PCR, with the following genes detected: tet(M) in 1 Lb. bulgaricus and 2 Strep. thermophilus isolates, ant(6) in 2 Lb. bulgaricus and 2 Strep. thermophilus isolates, and aph(3')-IIIa in 5 Lb. bulgaricus and 2 Strep. thermophilus isolates. The main threat associated with these bacteria is that they may transfer resistance genes to pathogenic bacteria, which has been a major cause of concern to human and animal health. To our knowledge, the aph(3')-IIIa and ant(6) genes were found in Lb. bulgaricus and Strep. thermophilus for the first time. Further investigations are required to analyze whether the genes identified in Lb. bulgaricus and Strep. thermophilus isolates might be horizontally transferred to other species.

Up-regulation of Twist induces angiogenesis and correlates with metastasis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly invasive tumor characterized by vigorous neovascularization. The purpose of this study is to examine the expression of Twist, a highly conserved bHLH transcription factor that is known to promote EMT, and evaluate its effect on tumor angiogenesis and metastasis of HCC. The mRNA expression of Twist, VEGF, E-cadherin, and N-cadherin was determined by Real-Time RT-PCR in 30 pairs of hepatocellular carcinomas and matched non-cancerous tissues. Immunohistochemistry was carried out to analyze the protein expression of Twist, VEGF, E-cadherin, and N-cadherin in 40 hepatocellular carcinoma cases. The staining of endothelial cells for CD34 was used to evaluate the MVD. We found that Twist mRNA and protein were both increased in HCC as compared to non-cancerous tissues. The HCC specimens showing positive Twist expression had a higher microvessel density than those without Twist expression. And up-regulated Twist protein was significantly associated with intrahepatic and extrahepatic metastasis (p=0.048 and P=0.039 respectively). In addition, patients with Twist expression had poor prognosis. We also found that the expression of Twist positively correlated with up-regulation of VEGF and N-cadherin (P=0.002 and p=0.016 respectively), but not with downregulation of E-cadherin in HCC. Our results demonstrate that Twist may play an important role in the angiogenesis and metastasis of HCC. Twist expression may become a potential novel prognostic factor for the disease survival of HCC.

Reversing adriamycin resistance of human breast cancer cells by hyperthermia combined with Interferon alpha and Verapamil

One of the major obstacles related to chemotherapy is resistance against anticancer drugs, including Adriamycin (ADM). The purpose of the present work is to investigate the reversal effects on ADM resistance by hyperthermia (42.5 degrees C) combined with two reversal agents (Interferon alpha and Verapamil) in MCF-7/ADR (ADM-resistant MCF-7 breast cancer cell line), and its relevant molecular mechanism of action. The cell survival rate and ADM IC50 of different experiment groups were measured by MTT test. The quantitative expression of MDR1 gene in cells was detected by Real-time PCR, and the expression of P-glycoprotein (P-gp) on the cells surface and the intracellular ADM accumulation was detected by flow cytometry (FCM). The ADM IC50 of the MCF-7/ADR cells decreased 830-fold after combined with Interferon alpha (IFN-alpha) and Verapamil (VRP). Although there was no distinction in the mRNA expression of MDR1, the P-gp on the MCF-7/ADR cell membrane was significantly reduced and the cellular ADM uptake increased markedly as compared to pretreatment. Our results suggeste that hyperthermia induces a considerably reversal activity against ADM resistance synergizing other reversal agents (IFN-alpha and VRP). The reversal mechanism needs further study. However, these features of hyperthermia may be exploited in clinical cancer chemotherapy.

Effect of bilateral testicular resection on thymocyte and its microenvironment in aged mice

AIM

To observe the changes in thymocyte and its microenvironment in aged mice after bilateral testicular resection.

METHODS

In male old mice, at the 25th day after testicular resection, the peripheral blood and thymus were collected. Blood and thymus suspension smears were prepared for quantitative histochemistry and immunohistochemistry study under light and electron microscopes.

RESULTS

In testes resected mice the size and the weight of thymus were markedly increased. The demarcation between cortex and medulla was clear. The cortex was thickened and the cell density was increased. The ratio of cortex/medulla stereometry was increased. The total cell count, thymocyte count, the percentage of acid alpha-naphthyl acetate esterase (ANAE) positive thymocytes, nonlymphocytes and the rosette formation of macrophages and thymocytes were all increased. The thymocytes surrounded closely to the light thymic epithelial cells, dendritic cells or macrophages. The lymphocytes, particularly the ANAE positive lymphocytes of peripheral blood were increased.

CONCLUSION

After bilateral testicular resection, the thymus of aged male mice showed morphological regeneration and the thymocytes and its microenvironment appeared to be definitely improved. It is suggested that testicular resection may improve immune function.

A field trial of detection and treatment of nerve function impairment in leprosy--report from national POD pilot project

As part of a collaborative project between the Ministry of Health of China (MOH) and The Leprosy Mission International (TLMI) on leprosy rehabilitation and prevention of disability (POD), a total of 1407 patients was monitored for possible nerve function impairment (NFI) through standardized clinical nerve function assessment between May 1995 and February 1998. Of these, 191 patients were found to have NFI and were put on a fixed regimen of prednisolone. In this study, 36.7% of NFI occurred before diagnosis of leprosy, 35.6% developed during MDT and 25.7% after their release from MDT. Overall, 7.5% (105 out of 1407) of all patients, or 55.9% of patients with NFI, suffered from silent neuropathy. Of the affected nerves, 62.6% had silent neuropathy. Sensory impairment responded to prednisolone satisfactorily, giving a recovery rate of 73.8%, 76.5% and 81.0% in ulnar, median and posterior tibial nerve, respectively. Sensibility in patients even with a NFI duration longer than 6 months made significant improvement (p < 0.05). Motor function improvement was less satisfactory, especially in ulnar and c. popliteal nerve. The possible reasons are analysed. Our findings with regard to sensibility changes confirm that once it becomes clinically detectable, NFI is no longer at the 'early' stage. More sensitive tests are necessary to detect real 'early' sensory impairment in the field. Our study also indicates that with well-trained field staff and proper equipment for nerve function assessment, early detection and treatment of NFI can be practical and effective.

[Study on determinationing the bone mineral content as diagnostic value for occupational fluorosis]

The results of determination of the bone density of 194 workers exposed to fluorine by SPA-III type osteodensimeter were compared with people unexposed to fluorine, and with the results of diagnosing the luorosis by X-ray. (1) The abnormal bone cortex thickness and density rate in the people exposed to fluorine was significantly higher than the ordinary people (P < 0.05). (2) In the people exposed to fluorine, the correspondency rate of determining fluorosis of bone by X-ray and by osteodensimeter were 84.6%, and results of the two methods had no significant difference (P > 0.05). (3) In another group of 155 cases, whose values of hair fluorine and urinary fluorine were higher than the ordinary people (66.5%), the abnormal density of bone of 103 cases had been determined by osteodensimeter, but not by X-ray. This showed that the diagnosis of early changes of osteofluorosis by osteodensimeter was more sensitive than by X-ray. (4) There was close association between the unusual rate of osteodensity and the superstandard rate of hair fluorine and urinary fluorine. The above findings indicated the determination of bone density can be used as a diagnostic index for occupational fluorosis.

Cloning and expression of a cardiac/brain beta subunit of the L-type calcium channel

The skeletal muscle dihydropyridine receptor/Ca2+ channel is composed of five protein components (alpha 1, alpha 2 delta, beta, and gamma). Only two such components, alpha 1 and alpha 2, have been identified in heart. The present study reports the cloning and expression of a novel beta gene that is expressed in heart, lung, and brain. Coexpression of this beta with a cardiac alpha 1 in Xenopus oocytes causes the following changes in Ca2+ channel activity: it increases peak currents, accelerates activation kinetics, and shifts the current-voltage relationship toward more hyperpolarized potentials. It also increases dihydropyridine binding to alpha 1 in COS cells. These results indicate that the cardiac L-type Ca2+ channel has a similar subunit structure as in skeletal muscle, and provides evidence for the modulatory role of the beta subunit.

Heterologous regulation of the cardiac Ca2+ channel alpha 1 subunit by skeletal muscle beta and gamma subunits. Implications for the structure of cardiac L-type Ca2+ channels

High threshold L-type Ca2+ channels of skeletal muscle are thought to consist of a complex of alpha 1, alpha 2 delta, beta, and gamma subunits. Expression of the cloned alpha 1 subunit from skeletal and cardiac muscle has established that this protein is the dihydropyridine-sensitive ion-conducting subunit. However, the kinetics of the skeletal muscle alpha 1 alone expressed in mouse L-cells were abnormally slow and were accelerated to within the normal range by coexpression with the skeletal muscle beta subunit. The kinetics of cardiac muscle alpha 1 were also slowed but to a lesser extent and were not altered by coexpression with skeletal muscle alpha 2. We show here that coexpression of the skeletal muscle beta subunit with the cardiac alpha 1 subunit in Xenopus laevis oocytes produced: 1) an increase in the peak voltage-sensitive current, 2) a shift of the peak current-voltage relationship to more hyperpolarized potentials, and 3) an increase in the rate of activation. Coexpression of the skeletal muscle gamma subunit did not have a significant effect on currents elicited by alpha 1. However, when gamma was coexpressed with beta and alpha 1, both peak currents and rates of activation at more negative potentials were increased. These results indicate that rather than simply amplifying expression of alpha 1, heterologous skeletal muscle beta and gamma subunits can modulate the biophysical properties of cardiac alpha 1.

Molecular diversity and function of G proteins and calcium channels

General features of signal transduction by G proteins and structural properties of G-protein-modulated calcium channels are described. Recent results on roles of beta gamma dimers in signal transduction, on the kinetic properties of Gi alpha subunits and structural diversity of Go alpha subunits are discussed, as are the background and current state of our knowledge of the modulation of calcium channels by G proteins.

The use of PCR to probe calcium channel diversity

Voltage-dependent calcium channels are a diverse set of proteins that can be classified into at least 3 classes based on their electrophysiological and pharmacological behavior. Our studies have focused on the dihydropyridine-sensitive L-type class, which has two isoforms that have been cloned and expressed. In this report we describe the development of a polymerase chain reaction (PCR, Cetus) to probe for the expression of L-type calcium channel isoforms. We describe the optimization of the PCR reaction in terms of the following: methods for producing the template cDNA, concentration of primers, and magnesium concentration. In addition, we discuss our efforts to understand the factors involved in the design of oligonucleotides for PCR primers. These studies led to the following conclusions: 1) that primers should be less than 30 base pairs in length, 2) that the addition of extraneous polylinker sequences on the 5' end of the primer has no effect, 3) that the primer should not be located in regions where secondary structure may exist, and 4) that non-degenerate primers can be used to amplify homologous gene family members. We also present methods for subcloning PCR fragments, which allow the product of a single reaction to be subcloned and sequenced. We illustrate the use of all these techniques with RNA from mouse ovary, where we have discovered the expression of the cardiac isoform of the dihydropyridine-sensitive L-type calcium channel, and the expression of a novel sequence that we postulate to be an isoform of L-type calcium channels.

Molecular diversity of L-type calcium channels. Evidence for alternative splicing of the transcripts of three non-allelic genes

The diversity of L-type calcium channels was probed using the polymerase chain reaction and primers based on regions conserved in the L-type skeletal muscle (CaCh 1) and cardiac calcium channels (CaCh 2). Related sequences were amplified from human heart, hamster heart, rabbit heart, mouse ovary, mouse BC3H1 cells, and hamster insulin-secreting (HIT) cells. Sequencing of various clones revealed the presence of alternate splicing in gene products coding for CaCh 1, CaCh 2, and a related calcium channel. This related gene product, which we refer to as neuroendocrine or CaCh 3, is expressed in brain and endocrine cells. The diverse products can be explained by the use of alternate exons of equal size, which account for changes in amino acid composition, in combination with an alternate splice acceptor site or an exon skipping event, which produces channels of variable length. Four variants were defined for the gene 3 product, subtypes 3a, 3b, 3c, and 3d that differed in both the sequence of the third membrane spanning segment of the fourth repeat unit (IVS3) and in the size of the linker between this and the fourth membrane spanning segment (IVS4). Three CaCh 2 variants were cloned, subtypes 2a, 2c, and 2d, that are homologous to the a, c, and d variants of CaCh 3. For the skeletal muscle calcium channel only two variants were isolated. They are homologous to those of the a and c subtypes of CaCh 2 or 3, in that they differ only in the size of the IVS3 to IVS4 linker. These results demonstrate that calcium channel diversity is created by both the expression of distinct genes and the alternate splicing of these genes.

Studies on the structural requirements for the activity of the skeletal muscle dihydropyridine receptor/slow Ca2+ channel. Allosteric regulation of dihydropyridine binding in the absence of alpha 2 and beta components of the purified protein complex

A rabbit skeletal muscle dihydropyridine (DHP) receptor can be purified as an alpha 1-alpha 2-delta-beta-gamma complex, of which alpha 2 and delta are disulfide bonded. This complex has Ca2+ channel activity when incorporated into lipid bilayers. We reported recently that expression of alpha 1 in murine L cells (LCa cells) leads to appearance of both DHP binding and Ca2+ currents, and that we failed to detect alpha 2 by immunoblotting. LCa cell Ca2+ channel currents resembled those in rabbit skeletal muscle in their sensitivity to both voltage and the DHP agonist Bay K 8644, but differed in that they responded to depolarization much more slowly. We now report details of the molecular cloning of the cDNA encoding the 1857-amino acid long alpha 1 transfected into the L cells and results from studies on expression of beta, as well as, on allosteric regulation of DHP binding to these cells. The alpha 1 cDNA was cloned by a combination of cDNA library screening (5355 base pairs) and chemical synthesis (508 base pairs). Using rabbit labeled beta cDNA, which cross-reacts with murine beta mRNA, we failed to observe cross-hybridizing beta mRNA in LCa cells. Using a labeled single stranded 200-base long rabbit alpha 2 cDNA that cross-reacts with mouse alpha 2 mRNA, we likewise failed to observe cross-hybridizing alpha 2 mRNA in LCa cells and hence confirmed the absence of an endogenous murine alpha 2 in these cells. Using LCa cell membranes as DHP receptor source we found the binding of the DHP antagonist (+)-[3H]PN200-110 to be regulated by both verapamil and diltiazem as it is in rabbit skeletal muscle membranes. However, we noted a difference; at concentrations above 10(-6) M, verapamil inhibited residual DHP binding in LCa but not in skeletal muscle membranes. We conclude that neither alpha 2 nor beta are essential for expression of alpha 1 on the cell surface, or for its functioning as a voltage-gated Ca2+ channel, or for its allosteric regulation of DHP binding by Ca2+ channel antagonists. The studies neither exclude roles for gamma and delta, nor for alpha 2 or beta in determining more subtle properties of this channel.

The interactions of 1,4-dihydropyridines bearing a 2-(2-aminoethylthio)methyl substituent at voltage-dependent Ca2+ channels of smooth muscle, cardiac muscle and neuronal tissues

The Ca2+ channel antagonistic potencies of tiamdipine [2-(2-aminoethylthio)methyl-3-carboethoxy-5-carbomethoxy-6-m ethyl-4-(3- nitrophenyl)-1,4-dihydropyridine] and nifedipine [2,6-dimethyl-3,5-dicarbomethoxy-4-(2-nitrophenyl)-1,4-dihydrop yri dine] analogs bearing phenyl ring substituents were studied using pharmacologic and radioligand binding techniques. Additionally, analogs of tiamdipine possessing (2-aminoethylthio)methyl-, (2-acetamidoethylthio)methyl- and (2-pyrrolidinylmethylthio)methyl- groups at the C2 position of the 1,4-dihydropyridine ring have been studied. Tiamdipine and nifedipine analogs inhibited K(+)-induced contractile responses in rat tail artery. IC50 values of 4-phenyl ring substituted 2-(2-aminoethylthio)methyl tiamdipine analogs ranged from 10(-7) mol/l to 10(-8) mol/l. However, the corresponding 4-phenyl ring substituted nifedipine analogs covered a wider range of potency from 10(-6) mol/l to 10(-9) mol/l. KI values of the corresponding tiamdipine analogs for the inhibition of specific [3H]PN 200-110 [(+)-[3H]isopropyl-4-(2,1,3-benzoxadiazol-4-yl)-1,4-dihydro-5- methoxycarbonyl-2,6-dimethyl-3-pyridinecarboxylate] binding ranged from 10(-7) mol/l to 10(-9) mol/l in guinea pig ileal and rat heart membranes and rat brain synaptosomes. The two stereoisomers of tiamdipine and its analog 2-(2-acetamidoethylthio)methyl-3-carboethoxy-5-carbomethoxy- 6-methyl-4-(3- nitrophenyl)-1,4-dihydropyridine, and the four stereoisomers of 2-(2-pyrrolidinylmethylthio)methyl-3-carboethoxy-5-carbom eth oxy-6-methyl-4-(3- nitrophenyl)-1,4-dihydropyridine showed high stereoselectivity ratios of approximately (-)/(+) = 100 and 1000 in pharmacologic and binding experiments, respectively. The inhibitory actions of 2-(2-aminoethylthio)methyltiamdipine analogs against K(+)-induced contractile responses in rat tail artery developed very slowly requiring at least 2 h for maximum effect.(ABSTRACT TRUNCATED AT 250 WORDS)