Contact angle, protein adsorption and osteoblast precursor cell attachment to chitosan coatings bonded to titanium

Chitosan, a derivative of the bio-polysaccharide chitin, has shown promise as a bioactive material for implant, tissue engineering and drug-delivery applications. The aim of this study was to evaluate the contact angle, protein adsorption and osteoblast precursor cell attachment to chitosan coatings bonded to titanium. Rough ground titanium (Ti) coupons were solution cast and bonded to 91.2% de-acetylated chitosan (1 wt% chitosan in 0.2% acetic acid) coatings via silane reactions. Non-coated Ti was used as controls. Samples were sterilized by ethylene oxide gas prior to experiments. Contact angles on all surfaces were measured using water. 5 x 10(4) cells/ml of ATCC CRL 1486 human embryonic palatal mesenchyme (HEPM) cells, an osteoblast precursor cell line, were used for the cell attachment study. SEM evaluations were performed on cells attached to all surfaces. Contact angles and cell attachment on all surfaces were statistically analyzed using ANOVA. The chitosan-coated surfaces (76.4 +/- 5.1 degrees) exhibited a significantly greater contact angle compared to control Ti surfaces (32.2 +/- 6.1 degrees). Similarly, chitosan-coated surfaces exhibited significantly greater (P < 0.001) albumin adsorption, fibronectin adsorption and cell attachment, as compared to the control Ti surfaces. Coating chitosan on Ti surfaces decreased the wettability of the Ti, but increased protein adsorption and cell attachment. Increased protein absorption and cell attachment on the chitosan-coated Ti may be of benefit in enhancing osseointegration of implant devices.     

Comparison of serum specific IgE antibodies to staphylococcal enterotoxins between atopic children with and without atopic dermatitis

BACKGROUND: The skin of patients with atopic dermatitis (AD) exhibits a striking susceptibility to colonization and infection by Staphylococcus aureus. The exotoxins secreted by S. aureus can act as superantigens and classic allergens, inducing the production of functionally relevant specific IgE antibodies. The aim of this study was to compare the levels and positive rates of serum staphylococcal enterotoxin A (SEA)- and staphylococcal enterotoxin B (SEB)-specific IgE between atopic children with and without AD. METHODS: Sixty children with AD, 55 children with respiratory allergy without AD, and 24 nonatopic healthy children were studied. The levels and positive rates of serum SEA- and SEB-specific IgE were compared among three groups. The correlation between the levels or positive rates of serum SEA/SEB-specific IgE and the severity of AD or the presence of previous skin infections was studied. RESULTS: The children with AD had significantly higher levels and positive rates of serum SEA- and SEB-specific IgE than the atopic children without AD (P < 0.001) and the nonatopic children (P < 0.001). There was no significant difference in the levels and positive rates of serum SEA- and SEB-specific IgE between the atopic children without AD and the nonatopic children. With or without adjustment for the potential confounding effect of total serum IgE levels, the levels and positive rates of serum SEA- and SEB-specific IgE were significantly correlated with severity of AD (P <0.005), but they were not significantly different between AD children with and without previous skin infections. CONCLUSIONS: SEA and SEB may contribute to chronic inflammation and exacerbation of AD through the IgE-mediated immune response.     

New poly(amide-imide) syntheses, 3. Preparation and properties of cardo poly(amide-imide)s derived from 9,9-bis(4-aminophenyl)fluorene,trimellitic anhydride,and various aromatic diamines

An imide-ring-containing dicarboxylic acid, N,N′-(9-fluorenylidenedi-1,4-phenylene)diphthal-imide-4-carboxylic acid ( 1 ), was prepared by condensation of trimellitic anhydride and 9,9-bis(4-aminophenyl)fluorene. A series of new aromatic cardo poly(amide-imide)s having inherent viscosities of 0,59-1,13 dL/g were prepared by the direct polycondensation of this diimide-diacid with various aromatic diamines using triphenyl phosphite and pyridine as condensing agents in 1-methyl-2-pyrrolidone (NMP) in the presence of calcium chloride. The polymers are amorphous and readily soluble in highly polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, NMP, and m-cresol. Transparent and tough films can be easily cast from the polymer solutions. The glass transition temperatures of these poly(amide-imide)s are above 320°C. Thermal analyses indicated that these polymers are fairly stable, and the 10% weight loss temperatures were recorded in the range of 532–622°C in nitrogen atmosphere.     

Roberts铜盐法测定蔗汁葡聚糖含量的热效应——淀粉对受热蔗汁葡聚糖测定的影响

作者从研究中发现:用Roberts铜盐法测定蔗汁样本葡聚糖含量时,所得结果与蔗汁的受热有关,受热蔗汁的测定值高于真实值,作者将这种现象暂称为Roberts铜盐法测定蔗汁样本葡聚糖含量的热效应。研究表明:蔗汁中的淀粉是引起热效应的重要因素。本文最后提出了一种由淀粉引起的热效应的可行校正方法。     

Premedical and medical school performance in predicting first-year residency performance

In the study reported here the authors examined the relationships among 40 measures of undergraduate college and medical school performance and competence in 18 medical care tasks during the first year of residency. A rating form was developed for the study to assess residents' competency in the medical care tasks and was sent to the directors of the residency programs entered by the graduates of a medical school. Stepwise multiple regression procedures were used to analyze the relationship between these ratings of residency performance and the residents' premedical and medical school performance and to identify the best predictors of residency performance for the 1982 and 1984 classes. A Rasch model analysis of the residency performance ratings indicated the ease or difficulty of each of the 18 tasks. The results provide information that would allow medical educators to use premedical and medical school performance to predict residents' competencies. The task of "clinically evaluates research and clinical data" was the most difficult for the graduates; that is, they were rated lower on it than on any other task. Two groups of measures of undergraduate and medical school performance were significantly related to performance in the residency: the Part II examination of the National Board of Medical Examiners (particularly the scores on the obstetrics-gynecology, medicine, surgery, and pediatrics subtests and the overall score) and the clerkships (particularly the third-year medicine clerkship, the fourth-year medicine clerkship, and the surgery clerkship).     

Changes in the health situation among the rural population and the challenges to the preventive services in China

80% of China's 1 billion population is rural. In response to the changing situation in rural health care work subsequent to profound economic rural structural reform, appropriate measures in Chinese rural health care work were taken. All levels of leaders in health care and other departments were instructed to continue the rural health care policy of "prevention first," and to expand the functions and tasks of prevention. Rural areas were to given top priority. To reform the current health organizational structure it was necessary to take into account several realities: The rural birth rate has dropped radically since liberation, as has the mortality rate. Life expectancy has increased, the combined effect being a population that is aging rapidly: people 65+ years old comprised 4.91% of the population in 1982. 32.2% of rural families are 1-child families, and the safeguarding of the health of children continues to be a high priority, as does the prevention of cardio- and cerebrovascular disease and malignant tumors, which as cause of 54.91% of mortality, has replaced infectious diseases as the main health threat. Occupational disease have become alarmingly more common as the effort to expand rural industry advances. The 3-level health care network is to continue to be reinforced: county facllities for training and care of complicated diseases, integrating multiple functions that were previously separate, township rural health centers for the development of prevention teams, and village level doctors. The rural medical system must, among other things, transform the medical model to a "biological, psychological, and social" medical model, mobilize various social sectors, and attempt to collect funds from various sources to support health care work and the prevention of disease.     

Hepatic arterial perfusion scintigraphy with Tc-99m-MAA. Use of a totally implanted drug delivery system

Tc-99m-MAA hepatic arterial perfusion scintigraphy ( HAPS ) using a totally implanted drug delivery system was employed for hepatic arterial chemotherapy in 147 patients (335 studies). Complete perfusion of the involved liver was seen in 88% of patients initially [more so in those with normal hepatic vascular anatomy (93%) than those with vascular variants (79%)] and remained good on follow-up. In 67 consecutive patients (95 studies), arteriovenous shunting to the lung ranged from 0.4 to 32% (mean, 6.2% +/- 4.1 S.D.). Uptake at the tip of the catheter was increased in 20% of patients, but good perfusion was usually maintained. A significant decrease in hepatic and/or extrahepatic perfusion associated with a "hot spot" at the tip of the catheter indicated hepatic arterial thrombosis. Extrahepatic perfusion was seen in 14% of cases, usually in the distribution of the stomach, small bowel, and spleen. Significant symptoms of drug toxicity were seen in 70% of patients with extrahepatic perfusion, compared to 19% of those without it.     

西安市雁塔区2016—2019年犬伤门诊暴露人群流行病学分析

目的 分析2016—2019年西安市雁塔区犬伤暴露处置门诊患者流行病学状况,为犬伤暴露处置门诊的规范化管理提供依据。 方法 采用描述性流行病学方法,对2016—2019年西安市雁塔区犬伤暴露处置资料进行描述。结果 2016—2019年西安市雁塔区共处置犬伤暴露患者46 697例,犬伤暴露率逐年增长,2019年为1 286.22/10万。女性暴露比男性高,占55.20%。20～<30岁是最高暴露年龄组,学生是犬伤暴露的主要职业人群。6—8月为高峰月份,占暴露总数的 33.02%,其中8月为最高暴露月份。Ⅱ级以上暴露为99.82%,Ⅱ级和Ⅲ级暴露分别占45.32%和54.50%;患者在12 h内进行免疫处理为39 210例,占83.97%,24 h以内的5 583例,占11.95%,超过24 h有1 904例,占4.08%。Ⅲ级暴露就诊患者犬伤免疫球蛋白使用率 35.30% ; 咬伤动物种类总计25种,前三位分别为犬伤者占62.69%,猫伤者占33.48%,鼠伤者占1.50%。 结论 2016—2019年西安市雁塔区犬伤暴露呈现逐年增高趋势,暴露后处置及时性较好,但防治工作中仍存在犬伤暴露患者处置不规范等问题,需有针对性地调整和改进防控策略 。     

河南省艾滋病防治成就与挑战——全球艾滋病发现40周年记

本文回顾了河南省艾滋病防治工作历程,分析总结取得的成就与面临的挑战,提出今后工作重点与建议。河南省从1995年发现首例艾滋病患者以来,根据不同时期流行特点采取了针对性的防治策略和措施,扩大了监测、治疗、高危行为干预等措施的覆盖面。全省HIV抗体检测人数从2011年的570万人次逐步增加到2020年1 617万人次,建立了166个艾滋病监测哨点,38个确证实验室,862个筛查实验室和2 989个检测点。抗病毒治疗覆盖率达到90.2%,艾滋病病死率降低至1.93%,单阳家庭阴性配偶的阳转率稳定在0.5%以下。下一步需要加强宣传教育的针对性,探索科学有效的防治策略,遏制艾滋病的传播和蔓延。