A Susceptible-infected Epidemic Model with Voluntary Vaccinations

An susceptible-infected epidemic model with endogenous behavioral changes is presented to analyze the impact of a prophylactic vaccine on disease prevalence. It is shown that, with voluntary vaccination, whether an endemic equilibrium exists or not does not depend on vaccine efficacy or the distribution of agent-types. Although an endemic equilibrium is unique in the absence of a vaccine, the availability of a vaccine can lead to multiple endemic equilibria that differ in disease prevalence and vaccine coverage. Depending on the distribution of agent-types, the introduction of a vaccine or, if one is available, a subsidy for vaccination can increase disease prevalence by inducing more risky behavior.I would like to thank one of the editors of the journal, Alan Hastings, for his comments and suggestions.     

Immunogenicity of a novel, bivalent, plant-based oral vaccine against hepatitis B and human immunodeficiency viruses

A synthetic chimeric gene, TBI-HBS, encoding the immunogenic ENV and GAG epitopes of human immunodeficiency virus (HIV-1) and the surface protein antigen (HBsAg) of hepatitis B virus (HBV), was expressed in tomato plants. Tomato fruits containing the TBI-HBS antigen were fed to experimental mice and, on days 14 and 28 post-feeding, high levels of HIV- and HBV-specific antibodies were present in the serum and feces of the test animals. Intraperitoneal injection of a DNA vaccine directing synthesis of the same TBI-HBsAg antigen boosted the antibody response to HIV in the blood serum; however, it had no effect on the high level of antibodies produced to HBV.Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Nutritional status, dietary intake and oral quality of life in elderly complete denture wearers

doi: 10.1111/j.1741‐2358.2011.00545.x Nutritional status, dietary intake and oral quality of life in elderly complete denture wearers Background and objective: The prevalence of malnutrition increases with age because of many factors. Edentulousness leads to the avoidance of many types of foods. The aim of this study was to determine whether elderly complete denture wearers have a higher risk of malnutrition than dentate controls. Material and methods: A Mini‐Nutritional Assessment (MNA) and a 3‐day dietary record were compiled for a group of fully dentates (21 women and 29 men; mean age 70.1 ± 6.1) and for a group of complete denture wearers (31 women and 16 men; mean age 70.1 ± 8.1). Socio‐demographic data and scores on the General Oral Health Assessment Index (GOHAI) questionnaire were collected. Results: Inter‐group comparison of MNA scores showed that more subjects in the edentulous group (21.3%) risked malnutrition than in the dentate group (0%). The variability of the MNA could be explained for 22% by dental status, 7% by loneliness and 4% by the GOHAI score (regression analysis). Both groups had insufficient energy intakes and deficits in vitamins and micronutrients; moreover, edentulous subjects had lower intakes than dentate subjects. Conclusion: The use of conventional dentures increases the risk of malnutrition in the elderly.     

A new approach to enhance oral bioavailability of Silybum Marianum dry extract: Association of mechanochemical activation and spray congealing

The aim of the work was to produce a delivery system for Silybum Marianum dry extract with enhanced oral bioavailability by combining two technologies (mechanochemical activation and spray congealing). Initially, the active was coground with sodium croscarmellose in a planetary mill in order to reach an activated state more prone to dissolution. DSC, XRD, FT-IR and LD analyses showed the formation of nanosized particles of dry extract, with reduced degree of crystallinity of the main crystalline flavolignans (silybine A and B). Then, microparticles containing the activated coground and, as comparison, the corresponding physical mixture of extract and polymer and the dry extract alone were produced by spray congealing technology using Gelucire^® 50/13 as a hydrophilic low m.p. carrier. Microparticles containing the activated coground were produced spherical in shape, achieved satisfactory yield and high encapsulation efficiency. These microparticles, in addition to a favourable in vitro solubilisation kinetic, in a preliminary in vivo study in five rats demonstrated their ability to improve very significantly the oral bioavailability of the main flavolignans of Silybum Marianum dry extract (silybin A and B). These results suggested that the association of mechanochemical activation and spray congealing could be considered an innovative and very useful approach to the oral delivery of Silybum Marianum. Furthermore, for the first time the possibility of successfully applying the spray congealing technology for the preparation of a herbal drug delivery system was shown.     

Protective role of purified cysteine proteinases against Fasciola gigantica infection in experimental animals

Fascioliasis is one of the public health problems in the world. Cysteine proteinases (CP) released by Fasciola gigantica play a key role in parasite feeding, migration through host tissues, and in immune evasion. There has been some evidence from several parasite systems that proteinases might have potential as protective antigens against parasitic infections. Cysteine proteinases were purified and tested in vaccine trials of sheep infected with the liver fluke. Multiple doses (2 mg of CP in Freund's adjuvant followed by 3 booster doses 1 mg each at 4 week intervals) were injected intramuscularly into sheep 1 week prior to infect orally with 300 F. gigantica metacercariae. All the sheep were humanely slaughtered 12 weeks after the first immunization. Changes in the worm burden, ova count, and humoral and cellular responses were evaluated. Significant reduction was observed in the worm burden (56.9%), bile egg count (70.7%), and fecel egg count (75.2%). Immunization with CP was also found to be associated with increases of total IgG, IgG(1), and IgG(2) (P<0.05). Data showed that the serum cytokine levels of pro-inflammatory cytokines, IL-12, IFN-γ, and TNF-α, revealed significant decreases (P<0.05). However, the anti-inflammatory cytokine levels, IL-10, TGF-β, and IL-6, showed significant increases (P<0.05). In conclusion, it has been found that CP released by F. gigantica are highly important candidates for a vaccine antigen because of their role in the fluke biology and host-parasite relationships.     

Comparison of diverse affinity based high-abundance protein depletion strategies for improved bio-marker discovery in oral fluids

Oral fluids (OF) have been suggested as a source of biomarkers for oral and systemic health, but as with other bio-fluids, the presence of high-abundance proteins interferes with the detection of lower-abundance biomarkers. Here, we compared the performance of four depletion treatments: triple depletion (TD) of amylases, albumins and immunoglobulin G; multiple depletion (MD) of amylases and a panel of 20 proteins, a combination of the two (EMD) and combinatorial peptide ligand library based depletion termed CPLL. TD, MD, EMD and CPLL removed 76%, 83%, 85% and 94% of total proteins, respectively, coupled with increased low abundance protein detection and narrowed dynamic range. 2-DE revealed that all depletion pretreatments successfully clarified areas hampered by high-abundance proteins; however, EMD and CPLL exposed the highest number of proteins. Quantitative MS of EMD samples relative to none treated samples indicated that most of downregulated proteins (>90%) were EMD target proteins. In conclusion, a multiple step EMD and CPLL depletion approaches bring about the highest number of protein detection ability and the best hampered-area clearance. As CPLL requires at least 10 fold more protein starting material, we suggest EMD pretreatment as a new detection tool in instances of low protein starting material.     

Real-time investigation of measles epidemics with estimate of vaccine efficacy

As part of measles elimination effort, evaluation of the vaccination program and real-time assessment of the epidemic dynamics constitute two important tasks to improve and strengthen the control. The present study aimed to develop an epidemiological modeling method which can be applied to estimating the vaccine efficacy at an individual level while conducting the timely investigation of the epidemic. The multivariate renewal process model was employed to describe the temporal evolution of infection by vaccination history, jointly estimating the time-dependent reproduction number and the vaccine efficacy. Analyzing the enhanced surveillance data of measles in Aichi prefecture, Japan from 2007-08, the vaccine efficacy was estimated at 96.7% (95% confidence interval: 95.8, 97.4). Using an age structured model, the vaccine efficacy among those aged from 5-19 years was shown to be smaller than that among those from 0-4 years. The age-dependent vaccine efficacy estimate informs the age-groups to be targeted for revaccination. Because the estimation method can rest on readily available epidemiological data, the proposed model has a potential to be integrated with routine surveillance.     

沈阳市居民乙肝感染状况调查

对不同性别、年龄的沈阳市居民乙型肝炎病毒血清标志物进行检测,分析HBV感染状况。采集3 780名健康体检者血清标本检测乙肝5项、ALT和TBIL,统计分析后的结果显示:乙肝感染率为3.28%,不同性别间结果无明显差异(P>0.05),但不同年龄组间乙肝感染率有显著差异(P<0.01),41～50岁年龄组感染率是6.23%,30岁以下和50岁以上感染率较低,分别为2.94%和1.84%;1、4、5感染模式占总感染例数的69.4%,HBV感染者中ALT或TBIL单项升高及二者均升高者占22.6%。沈阳市居民乙肝感染率低于全国平均水平,慢性乙肝感染较多,肝功能与乙肝感染病程不呈平行关系,疫苗接种可有效预防乙肝感染。     

脂肪细胞型脂肪酸结合蛋白疫苗对高脂喂养雌鼠体重和糖耐量的影响

目的:构建能诱导出针对脂肪细胞型脂肪酸结合蛋白(FABP4)特异性中和抗体的疫苗,为高脂诱导下肥胖和胰岛素抵抗的防治新途径提供理论和实验依据。方法:野生型C57BL/6J雌鼠随机分为疫苗组(n=10,高脂饲养)、佐剂组(n=10,高脂饲养)和空白对照组(n=10,普通饲养),分别予以皮下注射生物合成的FABP4蛋白、佐剂和磷酸盐缓冲液,观察比较各组抗体滴度、安全耐受性和体重、摄食量、空腹血糖、胰岛素抵抗指数(HOMA-IR)、糖耐量实验血糖曲线下面积(AUC)等指标。结果:疫苗组小鼠产生了高滴度的FABP4特异性抗体,并于第3轮加强免疫后达到平衡状态。首次免疫16周后,疫苗组小鼠体重高于空白对照组,但明显低于佐剂组(P<0.05);日平均摄食量高于空白对照组(P<0.05),与佐剂组无差异(P>0.05);空腹血糖、HOMA-IR、腹腔葡萄糖耐量实验AUC均明显低于佐剂组(P<0.05),与对照组无统计学差异(P>0.05)。结论:以FABP4作为抗原免疫小鼠,可产生高滴度特异性抗体IgG,有效降低高脂喂养野生型雌性小鼠体重、空腹血糖、HOMA-IR和血糖AUC等指标,为高脂诱导的肥胖和胰岛素抵抗的治疗提供了新的途径和初步证据,可进行深入研究。     

Neonatal vaccination against respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is the leading cause of pneumonia and bronchiolitis in infants and is the most frequent cause of lower respiratory tract infections in children.Efficacious vaccination...