Genetic diversity of the Leptospiral immunoglobulin-like (Lig) genes in pathogenic Leptospira spp.

Recent serologic, immunoprotection, and pathogenesis studies identified the Lig proteins as key virulence determinants in interactions of leptospiral pathogens with the mammalian host. We examined the sequence variation and recombination patterns of ligA, ligB, and ligC among 10 pathogenic strains from five Leptospira species. All strains were found to have intact ligB genes and genetic drift accounting for most of the ligB genetic diversity observed. The ligA gene was found exclusively in L. interrogans and L. kirschneri strains, and was created from ligB by a two-step partial gene duplication process. The aminoterminal domain of LigB and the LigA paralog were essentially identical (98.5 ± 0.8% mean identity) in strains with both genes. Like ligB, ligC gene variation also followed phylogenetic patterns, suggesting an early gene duplication event. However, ligC is a pseudogene in several strains, suggesting that LigC is not essential for virulence. Two ligB genes and one ligC gene had mosaic compositions and evidence for recombination events between related Leptospira species was also found for some ligA genes. In conclusion, the results presented here indicate that Lig diversity has important ramifications for the selection of Lig polypeptides for use in diagnosis and as vaccine candidates. This sequence information will aid the identification of highly conserved regions within the Lig proteins and improve upon the performance characteristics of the Lig proteins in diagnostic assays and in subunit vaccine formulations with the potential to confer heterologous protection.     

NPN日粮中添加益生素对绵羊生长性能及消化代谢的影响

选用40只5月龄的杂交绵羊(萨福克×小尾寒羊),随机分为两组,研究了非蛋白氮日粮中添加益生素对绵羊生长性能及消化代谢的影响。对照组饲喂C日粮(2%包被尿素)、试验组饲喂D日粮(2%包被尿素 0.2%益生素)。结果表明:(1)D日粮总增重和日增重要大于C日粮,有增加的趋势;但差异不显著;(2)D日粮能显著提高绵羊的沉积氮和降低尿氮的排出(P<0.05)。两组进食干物质、进食氮、粪氮、可消化氮之间差异不显著(P>0.05);D日粮可以提高沉积氮和可消化氮、沉积氮和进食氮的比例,降低尿氮与进食氮的比例;(3)D日粮可以显著提高绵羊的干物质、ADF的消化率以及酸不容灰分的利用率(P<0.05)。氮表观消化率和NDF消化率差异不显著。本试验结果表明,绵羊非蛋白氮中日粮添加0.2%益生素可以提高绵羊对非蛋白氮的利用率。     

鼠疫F1-V重组蛋白疫苗滴鼻免疫应答效果的研究

目的 以重组霍乱毒素B亚单位（rCT-B）为鼠疫F1-V重组蛋白的佐剂制备黏膜疫苗，观察小鼠诱导的黏膜免疫和系统免疫应答效果。方法以制备的鼠疫黏膜疫苗滴鼻免疫小鼠4次免疫后，采用间接ELISA检测血清特异性抗F1-V的IgG和IgA抗体及抗体亚型分类，检测鼻咽喉、肺、小肠及阴道灌洗液中特异性抗F1-V的黏膜分泌型IgA；采用流式细胞术检测鼻相关淋巴组织淋巴细胞、脾淋巴细胞、肠系膜淋巴结及小肠PP结T淋巴细胞表型的变化。结果以rCT-B为佐剂的鼠疫F1-V重组蛋白黏膜疫苗滴鼻免疫后，能够诱导血清中IgG、IgA抗体比正常对照组显著升高（P〈0．01），同时诱导鼻咽、肺、小肠和阴道内特异性黏膜抗体升高，尤其是肺和生殖道冲冼液内抗体升高极为显著（P〈0．01）。与单纯的F1-V组相比，不同剂量比例疫苗组都能诱导较高、较快的血清IgG、IgA和黏膜sIgA，其中1：2疫苗组能诱导更强的系统免疫和黏膜免疫，但是相比之下，5：1疫苗组是最合适的免疫剂量。结论rCT-B佐剂不仅能提高鼠疫F1-V黏膜疫苗的系统全身免疫应答，还能促进诱导呼吸道、消化道和生殖道等局部黏膜sIgA抗体，增强局部免疫应答，提示rCT-B佐剂能显著提高鼠疫感染的免疫应答作用，这为下一步疫苗的免疫保护评价奠定了基础。     

Association between bariatric surgery and anemia

ObjectivesSeveral studies have recently conducted to investigate the link between anemia and bariatric surgery (BS). The results from these studies, however, were inconsistent. Therefore, a meta-analysis was conducted to determine whether BS for weight loss is a risk factor for anemia.MethodsStudies were identified relevant papers published a cutoff date of May 2022 for meta-analysis by searching four electronic databases (PubMed, EMBASE, Web of Science and Cochrane Library). Pairs of authors conducted title and abstract, full-text assessment, data extraction and risk of bias assessment, and quality of articles. Random-effects models were used to estimate the pooled effect size and evaluated the overall quality of evidence. The sources of heterogeneity were assessed with I². The Newcastle-Ottawa scale (NOS) was used to assess the methodologic quality of selected studies. The publication bias was assessed using funnel plots and Egger's test statistics.ResultsIn all, eight studies comprising 3150 patients were finally included in the final study analysis. Of these, pooled analysis of eight studies detecting association between anemia and BS for weight loss yield a statistically significant correlation (SMD ?1.12 (?1.46—?0.78, I² = 93%). Subgroup analyses were performed according to postoperative follow-up time and operation method. Before 24 months postoperatively, no patient had a significant decrease in hemoglobin. More than 24 months after BS, patients show a significant reduction in hemoglobin. In addition, the hemoglobin level was not changed after sleeve gastrectomy (SG) and adjustable gastric banding (AGB) (SMD ?0.19 (?1.04—0.67, I² = 0% for SG; SMD ?0.30 (?0.82—0.22 for AGB), but the hemoglobin level was significantly reduced after Roux-en-Y gastric bypass (RYGB) (SMD ?1.19 (?1.52—?0.87, I² = 94.2%).ConclusionThis current meta-analysis found that at 24 months after RYGB, the patient's hemoglobin level was significantly reduced, increasing the risk of anemia. Therefore, attention should be paid to the occurrence of anemia after BS. A large, placebo-controlled, multi-center study is needed to clarify the role of BS for weight loss in this patient anemia.     

Association between chronic hepatitis C infection and metabolic syndrome: A meta-analysis

BackgroundHepatitis C virus (HCV) infected patients have been found to be more susceptible to metabolic syndrome (MetS), but the results remain unclear and lack of a meta-analysis.MethodsDatabases including PubMed, Web of Science, EMBASE and the Cochrane Library were searched to identify all studies concerning HCV and MetS. Funnel plots combined with Begg's tests and Egger's tests were used to analysis the possible publication bias. The odds ratios (ORs) with 95% confidence intervals (CIs) were used to access the effect of HCV infection on the risk of MetS.ResultsEight articles, involving a total of 57387 HCV patients were included. HCV infection was significantly associated with an increased incidence of MetS (OR = 1.73; 95% CI, 1.19–2.52). After adjustment according to the sensitivity analysis, one included article was removed to decrease the publication bias and high heterogeneity, of which the results showed that HCV infection was still associated with an increased incidence of MetS (OR = 1.93; 95% CI, 1.39–2.68).ConclusionsHCV patients tend to have a significant increased risk for MetS, but more large-scale studies are needed to confirm this and explore the exact mechanism.     

Effects of long-snake moxibustion on the HPA axis and liver 11β-HSD1 expression in rats with kidney yang deficiency: 长蛇灸对肾阳虚大鼠HPA轴及肝脏11β-HSD1的影响

ObjectiveTo observe the effects of long-snake moxibustion on the hypothalamic-pituitary-adrenocortical (HPA) axis and hepatic 11β-hydroxy steroid dehydrogenase type 1 (11β-HSD1) expression in rats with kidney yang deficiency to provide a basis for later in-depth exploration of the action mechanism of long-snake moxibustion on such rats.MethodsFifteen SPF-grade, male, SD rats were randomly divided into a blank control group, a model group, and a long-snake moxibustion treatment group, with five rats in each group. Hydrocortisone powder (30 mg/kg) was administered by gavage at a volume of 10 mL/kg to prepare the rat model of kidney yang deficiency. After successful modeling, the rats in the long-snake moxibustion treatment group underwent long-snake moxibustion treatment every other day (along the governor vessel from Dazhui (GV14) to Shenshu(BL23), for a period of 14 days. The remaining two groups were secured in the same way as the long-snake moxibustion treatment group, although they did not receive any treatment. The body weight, rectal temperature, and spontaneous activity count of the rats, as well as serum levels of corticotropin releasing hormone (CRH) and corticosterone (CORT) were detected by ELISA before modeling, after modeling, and after treatment. The amount of 11β-HSD1 protein in rat liver was determined by immunohistochemistry and Western blot analysis.ResultsCompared with the rats in the blank control group, those in the model group exhibited a significant decrease in the trend of body weight growth and in rectal temperature (P <0.05), as well as a slight yet non-significant decrease in spontaneous activity count (P >0.05); compared with the rats in the model group, the rats in the treatment group exhibited a significant increase in rectal temperature (P <0.05) and in spontaneous activity count (P <0.05). Moreover, after 14 days of treatment, compared with the rats in the blank, the rats in the model group exhibited a significant decrease in serum CORT content (P <0.05) and in the expression of 11β-HSD1 in the liver (P <0.05), as well as a slight yet non-significant decrease in serum CRH content (P >0.05); compared with the rats in the model group, the rats in the treatment group exhibited a significant increase in serum CRH content (P <0.05) and in the expression of 11β-HSD1 in the liver (P <0.05), as well as a slight yet non-significant increase in serum CORT content (P >0.05).ConclusionLong-snake moxibustion can increase the rectal temperature and spontaneous activity count of rats with kidney yang deficiency, improve the function of the HPA axis, and increase the expression of 11β-HSD1 in the liver.     

耐碳青霉烯革兰阴性杆菌耐药性及耐药基因blaKPC的分子特征

目的 探讨耐碳青霉烯类革兰阴性杆菌的临床耐药性及耐药基因blaKPC的分子特征。方法 分析2017年1月-2018年12月某院临床检出的耐碳青霉烯类革兰阴性杆菌。通过WHONET 5.6软件对药物敏感试验数据进行统计分析,采用PCR检测碳青霉烯耐药基因blaKPC、blaNDM、blaIMP、blaVIM、blaOXA-48,对PCR阳性产物进行DNA测序,分析耐药基因的分子结构特点。结果 共收集510株耐碳青霉烯类革兰阴性杆菌,其中耐碳青霉烯类肠杆菌科细菌（CRE）420株,耐碳青霉烯非肠杆菌科细菌90株。菌株主要来自重症监护病房（ICU）、神经外科和呼吸科,分别占60.8%、11.8%、5.3%;标本来自痰、脓性分泌物、静脉血、无菌中段尿,分别占66.9%、8.8%、8.2%、6.5%。耐碳青霉烯类革兰阴性杆菌对常用抗菌药物具有较高的耐药性。PCR结果显示,420株CRE中blaKPC、blaNDM、blaIMP的阳性率分别为54.3%（228/420）、1.2%（5/420）、1.4%（6/420）,未检测出blaVIM和blaOXA-48基因,其中肺炎克雷伯菌、产气肠杆菌、大肠埃希菌分别占携带blaKPC CRE的83.8%、11.8%、2.6%;其他少见菌种中也检出blaKPC基因。非肠杆菌科细菌中仅有2株鲍曼不动杆菌检测出blaKPC。DNA测序结果显示,174株携带blaKPC的菌株中173株检测为blaKPC-2、1株检测为blaKPC-1。结论 该地区耐碳青霉烯类革兰阴性菌以CRE为主,其中以携带blaKPC-2的肺炎克雷伯菌占绝对优势,其他菌株中也均有发现。提示临床需重点加强耐碳青霉烯类肺炎克雷伯菌的监测及预防,防控blaKPC的传播流行。     

Use of an exclusion assay to detect novel rickettsiae in field collected Amblyomma americanum

In the south-central United States, several tick-borne diseases (TbDs) occur at or near their highest levels of incidence of anywhere in the U.S. The diversity of Rickettsia species found in Amblyomma americanum continues to be under-characterized in this region and throughout the U.S. and Canada where this tick species is expanding. One reason for this lack of knowledge about Rickettsia diversity is the high prevalence of the endosymbiont Rickettsia amblyommatis that obscures detection of other bacteria in this genus. Focusing on unknown rickettsial agents, we used a recently described R. amblyommatis exclusion assay to screen 1909 A. americanum collected in Oklahoma City, Oklahoma, which resulted in eight ticks that had unique rickettsial sequences. Through the process of characterizing primary and secondary rickettsiae, we identified ticks primarily infected with Rickettsia rhipicephali and a Rickettsia species (2019-CO-FNY) previously linked with a canine rickettsiosis case in Tulsa, Oklahoma. We also identified a Rickettsia agent that was 97% identical with an endosymbiont of Amblyomma tonelliae and which aligned with archaic rickettsial species. Through this study, we further demonstrate the usefulness of this exclusion assay for rapid screening in large cohort A. americanum studies to identify a small number of ticks that contain poorly described and previously undocumented rickettsiae.     

Establishment of a model to assess mumps virus neurovirulence in neonatal Wistar rats

Mumps virus (MuV) is highly neurotropic and neurovirulent, hence, the neurovirulence of virus seeds used in the production of mumps vaccines must be tested. The previous neurovirulence evaluation method involves measuring the area of the cavity in the Lewis neonatal rat brain caused by MuV through paraffin sectioning and hematoxylin-eosin (HE) staining. However, the processes of paraffin sectioning and HE staining are time consuming and complicated. To solve this problem, in this study, a vibratome sectioning system was first deployed to evaluate MuV neurovirulence in the rat brain instead of paraffin sectioning and HE staining. The results showed that the vibratome sectioning method could assess the neurovirulence potential of MuV more objectively and efficiently. In addition, the effects of different MuV doses and the ages of the rats in days on this evaluation method were explored. The results indicate that MuV at no less than 10 50 % cell culture infective dose (CCID₅₀) could cause obvious cavity formation in 1-day-old rat brains. The neonatal rat model developed in this study could evaluate the neurovirulence of different MuV strains with high sensitivity and good repeatability.