An immune response profile model for immunogenicity quantitation

We propose an analytical model, which can simultaneously depict many fundamental characteristics of the immunogenicity of various vaccines. This model, the Immune Response (IR) profile, conveniently expresses the mathematical relation between pre- and post-vaccination titers. A vaccine's IR profile is antigen-specific, dose-dependent and post-vaccination interval-dependent. The maximal capability for serological response to a vaccine can be determined using this model irrespective of the dose administered, the post-vaccination assay interval, or the live or killed state of the vaccine. The IR profile obtained from analysis of booster vaccine responses in a limited number of seropositive study subjects can be used to predict maximal antibody titers which are expected after vaccination and can predict the geometric mean post-vaccination antibody titer of a cohort of subjects undergoing primary immunization. Using this model, it is anticipated that the immunoregulation implied by the IR profile may also prove to be correlated with cellular subpopulations and idiotypic antibody functions. Although derived from influenza vaccines analyses, the model successfully describes immune response characteristics following natural infection with malaria and following diphtheria and rubella vaccine administration.     

Anti-salmonella properties of kefir yeast isolates: An in vitro screening for potential infection control

The rise of antibiotic resistance has increased the need for alternative ways of preventing and treating enteropathogenic bacterial infection. Various probiotic bacteria have been used in animal and human. However, Saccharomyces boulardii is the only yeast currently used in humans as probiotic. There is scarce research conducted on yeast species commonly found in kefir despite its claimed potential preventative and curative effects. This work focused on adhesion properties, and antibacterial metabolites produced by Kluyveromyces lactis and Saccharomyces unisporus isolated from traditional kefir grains compared to Saccharomyces boulardii strains. Adhesion and sedimentation assay, slide agglutination, microscopy and turbidimetry assay were used to analyze adhesion of Salmonella Arizonae and Salmonella Typhimurium onto yeast cells. Salmonella growth inhibition due to the antimicrobial metabolites produced by yeasts in killer toxin medium was analyzed by slab on the lawn, turbidimetry, tube dilution and solid agar plating assays. Alcohol and antimicrobial proteins production by yeasts in killer toxin medium were analyzed using gas chromatography and shotgun proteomics, respectively. Salmonella adhered onto viable and non-viable yeast isolates cell wall. Adhesion was visualized using scanning electron microscope. Yeasts-fermented killer toxin medium showed Salmonella growth inhibition. The highest alcohol concentration detected was 1.55%, and proteins with known antimicrobial properties including cathelicidin, xanthine dehydrogenase, mucin-1, lactadherin, lactoperoxidase, serum amyloid A protein and lactotransferrin were detected in yeasts fermented killer medium. These proteins are suggested to be responsible for the observed growth inhibition effect of yeasts-fermented killer toxin medium. Kluyveromyces lactis and Saccharomyces unisporus have anti-salmonella effect comparable to Saccharomyces boulardii strains, and therefore have potential to control Salmonella infection.     

岷江上游4个栽培树种细根功能性状垂直分布的差异性

细根(直径≤2 mm)功能性状及垂直分布格局是反映植物对土壤资源吸收策略和影响森林地下生态过程的关键。本研究以岷江上游4个人工林树种连香树(Cercidiphyllum japonicum)、白桦(Betula platyphylla)、华山松(Pinus armandii)和油松(P.tabuliformis)为对象,调查不同海拔树木细根功能性状及其在不同土层间的垂直分布格局,并分析细根功能性状分布与构型之间的相关关系。结果表明:阔叶树种比针叶树种有更大的根长密度、生物量、比根长和比表面积,而直径反之;4个树种细根集中在0~20 cm土层,根长密度和生物量在较高海拔地段均显著大于较低海拔,且均随土壤深度增加而减少,但比根长、比表面积和直径无显著的海拔差异,随土层加深也无明显的垂直变化规律;针阔树种间的细根构型差异显著,但不受海拔差异的影响,阔叶树的细根分支强度与一级根数量显著大于针叶树种;一级根数和根尖密度与比根长以及分根比与根长密度和生物量均呈显著正相关,而分叉与几个细根功能参数均呈负相关;随着土层深度增加,细根总生长量明显减少,但细根资源利用效率和策略不变;5个细根功能性状的垂直分布格局差异明显,且受树种特性影响显著,细根分支构型对其垂直分布及资源获取策略具有显著影响。     

Repeated measures random forests (RMRF): Identifying factors associated with nocturnal hypoglycemia

Nocturnal hypoglycemia is a common phenomenon among patients with diabetes and can lead to a broad range of adverse events and complications. Identifying factors associated with hypoglycemia can improve glucose control and patient care. We propose a repeated measures random forest (RMRF) algorithm that can handle nonlinear relationships and interactions and the correlated responses from patients evaluated over several nights. Simulation results show that our proposed algorithm captures the informative variable more often than naïvely assuming independence. RMRF also outperforms standard random forest and extremely randomized trees algorithms. We demonstrate scenarios where RMRF attains greater prediction accuracy than generalized linear models. We apply the RMRF algorithm to analyze a diabetes study with 2524 nights from 127 patients with type 1 diabetes. We find that nocturnal hypoglycemia is associated with HbA1c, bedtime blood glucose (BG), insulin on board, time system activated, exercise intensity, and daytime hypoglycemia. The RMRF can accurately classify nights at high risk of nocturnal hypoglycemia.     

儿童重症监护病房医院感染暴发白色念珠菌血流感染4例分析

摘要 目的：探讨儿童重症监护病房白色念珠菌血流感染暴发的临床表现、危险因素、控制措施等,为预防和控制院内白色念珠菌血流感染暴发提供科学依据。方法：以2018年7月我院儿童重症监护病房发生的4例白色念珠菌血流感染暴发患儿为研究对象,分析患儿临床情况、临床特征、危险因素、暴发原因以及采取的预防控制措施。结果：4例医院感染暴发白色念珠菌血流感染患儿均存在基础疾病、有机械通气史、存在中心静脉或动脉置管、静脉或动脉置管前后均使用碘伏消毒、曾使用广谱抗生素、输血制品,白色念珠菌血流感染后最突出的临床表现均是发热。药敏方面,医院感染暴发的4例白色念珠菌感染患儿对唑类及5-氟胞嘧啶均耐药,但对两性霉素B均敏感。经拔除血管置管、减少或者避免广谱抗菌药的应用,根据药敏使用卡泊芬净及两性霉素B抗真菌等积极治疗,1例患儿放弃治疗后死亡,3例患儿顺利出院。通过Fisher确切概率法分析可知,留置中心静脉或动脉置管是儿童重症监护病房发生医院感染暴发白色念珠菌血流感染的危险因素（P<0.05）。结论：留置中心静脉或动脉置管是儿童重症监护病房发生医院感染暴发白色念珠菌血流感染的危险因素,医院感染暴发白色念珠菌血流感染患儿最突出的临床表现是发热,唑类及5-氟胞嘧啶耐药的患儿使用卡泊芬净及两性霉素B可能获得较好的治疗效果。     

非阿片类镇痛复合静脉全麻在鼾症手术患者中的疗效

目的:观察三重措施预防为基础,联合非阿片镇痛药复合静脉全麻在行鼾症手术患者术后恶心呕吐的应用效果。方法:选择择期行鼾症手术男性病人80例,随机分为两组:吸入麻醉组(inhalation group, IHLA组)和静脉麻醉组(intravenous group, TIVA组),每组40例,两组均采用三重措施预防恶心呕吐,IHLA组采用以舒芬太尼为基础复合七氟烷吸入麻醉,TIVA组以氯胺酮和右美托咪定镇痛基础上丙泊酚全凭静脉麻醉。评估两组病人恶心呕吐危险系数,采用李克特量表(Likert scale),记录并分析两组患者术后6~8 h在麻醉后监测治疗室(post anesthesia care unit, PACU)及病房24 h恶心呕吐发生情况及补救用药用量。结果:两组患者一般临床资料、恶心呕吐风险评分、手术时间、术后恢复期补救用药量人数无显著差异(P>0.05);IHLA组在PACU恶心呕吐发生率为39.5%,TIVA组发生率为18.9%,两者相比有显著性差异(P<0.05);IHLA组病房24 h恶心呕吐严重程度高于TIVA组,两组术后需要补救应用抗呕吐药物用量无显著差异(P>0.05)。结论:以三重措施预防为基础,与吸入麻醉相比,非阿片类镇痛药复合静脉麻醉可以减少肥胖病人鼾症手术术后恶心呕吐发生率和严重程度,降低围术期风险,有利于患者早期恢复。     

我国福寿螺入侵现状和防控研究进展

福寿螺原分布于南美洲,20世纪80年代作为一种水生经济生物引入我国,后因食味不佳被弃于水生环境,因其具有繁殖力高、适应性强、食性杂等特点,在我国多个区域迅速扩散入侵,已给农业生产、生态系统、人类健康等造成了严重的危害。文章对福寿螺入侵现状进行了深入分析与系统总结,介绍了现有福寿螺防控技术手段,重点阐述环境友好型福寿螺防控技术并对其进行了研究展望。目前,针对福寿螺防控实施的多种物理、化学和生物措施,治理效果不一,植物源生物控制技术因具有更高效、更经济、对非靶细胞更安全等优点,成为防治福寿螺的研究热点。然而此类研究多数集中于简单的毒杀效果试验,较少涉及毒杀机理、生殖系统等。本文旨在为全面了解我国福寿螺入侵现状、防控研究进展提供理论指导,为进一步探究福寿螺防控技术提供对策与新的思路。     

Fungal ovicidal activity on Toxocara canis eggs

BackgroundVisceral toxocariasis is a parasitic zoonosis caused by Toxocara canis. The prevalence of this parasite in dogs, soil contamination and the resistance of eggs increase human exposure to the disease. Moreover, the difficulties of the control measures justify the need for alternative ones.AimsThe objective of this study was to evaluate the in vitro ovicidal activity of fungi isolated from soils from public places in the city of Pelotas, Rio Grande do Sul, Brazil, on Toxocara canis.MethodsSamples of soil from ten localities were inoculated onto Petri dishes with 2% water–agar (WA) that contained antibiotics, and incubated at 25 °C/21 days. Isolated fungi were tested in vitro for ovicidal activity, with five replicates. One mL of an embryonated Toxocara canis egg suspension (10³ eggs) was poured over the fungal cultures after 10 days of growth. At intervals of 7, 14 and 21 days, 100 eggs were removed from each plaque and evaluated by optical microscopy.ResultsAcremonium, Aspergillus, Bipolaris, Fusarium, Gliocladium, Mucor and Trichoderma were isolated from the soil. A significant ovicidal type 3 effect was observed in Trichoderma, Fusarium solani complex and Acremonium. Those isolates from the genus Trichoderma showed their ovicidal effect on the 14th day of fungus–egg interaction. The other fungal genera tested showed a type 2 effect.ConclusionsThese results suggest that the use of Trichoderma and Fusarium solani complex in biological control of T. canis is promising; however, further studies should be performed.     

Human impacts on minimum subsets of species critical for maintaining ecosystem structure

Humans have indirectly influenced species at lower trophic levels by driving losses of apex consumers. Furthermore, humans have indirectly influenced species at higher trophic levels by driving losses of primary producers. Beyond these broad classes of apex consumers and primary producers, it remains challenging to identify minimum subsets of species that are particularly important for maintaining ecosystem structure and functioning. Here we use a novel method at the intersection of control theory and network theory to identify a minimum set of driver node species upon which ecosystem structure strongly depends. Specifically, humans could unintentionally completely restructure ecosystems (i.e., change species abundances from any initial values to any final values, including zero) by altering the abundances of these few critical driver node species. We then quantify the proportion of these driver nodes that are influenced by humans, top predators, and primary producers in several marine food webs. We find that humans could unintentionally completely restructure marine food webs while only directly influencing less than one in four species. Additionally, humans directly influence: (1) most or all of the species necessary to completely restructure each network, (2) more driver nodes than top predators, and at least as many driver nodes as primary producers, and (3) an increasing proportion of driver nodes over time in the Adriatic Sea. We conclude that humans have potentially huge impacts on marine ecosystems while directly influencing only the relatively small subset of species that are currently fished. It may be possible to reduce unintentional and undesirable cascading human influences by decreasing human impacts on driver node species in these and other food webs.