海马区星形胶质细胞培养上清液体外诱导人脂肪基质细胞向神经元样细胞的分化

目的:观察海马区星形胶质细胞培养上清液能否在体外诱导人脂肪基质细胞向神经元样细胞分化。方法:实验于2004-10/2005-06在华北煤炭医学院中心实验室完成。在无菌条件下从Wistar乳鼠分离出海马组织,从分离的海马组织中获得星形胶质细胞,并收集其培养上清液。取外科手术获得的人腹部皮下脂肪组织进行人脂肪基质细胞的原代培养。30例患者均知情同意。取第3代人脂肪基质细胞接种到培养孔中,预先放置无菌盖玻片的24孔培养板,制备细胞爬片或者接种到培养瓶中,细胞生长达50%～60%融合时,去除培养液,换为海马区星形胶质细胞培养上清诱导液进行诱导,对照组培养液为无血清培养基。倒置相差显微镜下连续观察细胞生长情况和形态变化,应用免疫细胞化学、鉴定神经前体细胞的特异性标志神经巢蛋白、神经细胞的特异性标志神经元特异性烯醇化酶、微管联合蛋白2和神经胶质细胞的特异性标志胶质纤维酸性蛋白的表达。结果:①诱导培养第3天,部分人脂肪基质细胞开始变形,从原先的细长梭状细胞变成神经元样细胞,可见细胞伸出突起,多为双极或多极细胞。②刚分离接种的人脂肪基质细胞镜下呈圆形,悬浮状态,接种后24h内贴壁,并开始伸展,多呈梭形。1周后细胞融合成单层,排列出现方向性,但有少量圆形及卵圆形细胞混杂生长。③第4,5代人脂肪基质细胞在诱导48h后形态即开始发生变化,扁平的胞体较预诱导后逐渐回缩,向外伸出突起,72h后扁平的胞浆向胞核收缩,突起继续延长,以后随时间进展,具有典型神经细胞形态特点的细胞数量逐渐增多,形成双极或多极细胞。④免疫细胞化学检测人脂肪基质细胞诱导5d后发现有(10.5±3.7)%神经巢蛋白、(38.4±5.2)%胶质纤维酸性蛋白、(15.7±2.3)%神经元特异性烯醇化酶表达,未见微管联合蛋白2的表达。结论:海马区星形胶质细胞培养上清液可以在体外诱导人脂肪基质细胞向神经元样细胞方向分化。     

Neurophysiological methods for the assessment of spasticity: The Hoffmann reflex, the tendon reflex, and the stretch reflex

Purpose: To review the literature concerning neurophysiological methods to assess spasticity with respect to mechanisms and methodology, and to describe the three most commonly used methods: the Hoffmann reflex (H-reflex), the Tendon reflex (T-reflex), and the Stretch Reflex (SR). Method: A systematic internet database search was performed to identify neurophysiological measurement methods of spasticity. A systematic exclusion procedure resulted in 185 included references, completed by additional informal search. For this paper, information about the H-, T- and stretch reflexes was extracted from these references. Results: Although the reflexes are basically monosynaptic, there are many supraspinal pathways which modulate the responses in terms of their amplitude and latency. As a consequence the methods are sensitive to a considerable number of experimental conditions and are characterized by a moderate reliability and sensitivity. Correlations with other (i.e. biomechanical, neurophysiological or clinical) spasticity assessment parameters are moderate to poor. Standardised and broadly accepted protocols are still largely lacking preventing an effective exchange of knowledge. Conclusions: The clinical and experimental use of the three methods is restricted due to moderate reliability and sensitivity. It is recommended to perform combined neurophysiological - biomechanical assessment of spasticity during active, functional movement.     

Assessing health system provision of adolescent preventive services: the Young Adult Health Care Survey

BACKGROUND: Adolescents often do not receive recommended preventive counseling and screening services. Few measures are available to assess health care system performance in this area. OBJECTIVE: Develop a reliable, valid, and feasible method for measuring adherence to consensus guidelines for adolescent preventive counseling and screening services. METHODS: The 45-item Young Adult Health Care Survey (YAHCS) was tested with a diverse group of commercially and publicly insured adolescents enrolled in managed care organizations (n = 4,060). Psychometric, bivariate, and multivariate analyses were conducted to assess the reliability, validity, and patterns of variation in the preventive care measurement scales derived from the YAHCS. RESULTS: YAHCS measurement scales demonstrated strong construct validity (mean factor loading = 0.64) and reliability (mean Cronbach's alpha = 0.77). Average preventive counseling and screening scores ranged from 18.2% for discussing risky behavior topics to 50.4% for discussing diet, weight, and exercise topics. Adolescent demographic, health care use, and payer factors explained a small amount of variation across adolescent scores on YACHS scales (mean R2 = 0.086). Females and older teens were more likely to report private time with providers and counseling and screening on topics related to sex. Overall, the odds of receiving preventive counseling and screening for adolescents who reported having private time with providers, engaging in risky behaviors, or both were higher than for adolescents who did not meet privately or report risky behaviors (private visit OR, 3.60; 95% CI, 2.91-4.47; risky behaviors OR, 2.02; 95% CI, 1.62-2.52). CONCLUSIONS: The YAHCS provides a feasible, reliable, and valid method for assessing adherence to adolescent preventive services guidelines. It differentiates among varied aspects of preventive care provided to adolescents and is promising as a potential measure of health plan and provider quality. Improved performance on the YAHCS would indicate progress toward the achievement of Healthy People 2010 goals.     

Age-related changes in microvascular permeability: a significant factor in the susceptibility of children to shock?

During studies of the pathogenesis of dengue shock syndrome, a condition largely confined to childhood and characterized by a systemic increase in vascular permeability, we observed that healthy controls, age-matched to children with dengue shock syndrome, gave high values of filtration capacity (K(f)), a factor describing vascular permeability. We hypothesized that K(f) might be age dependent. Calf K(f) was studied in 89 healthy Vietnamese subjects aged 5 to 77 years. The K(f) was highest in the youngest children [7. 53 (1.96-15.46) K(f)U; median (range); where the units of K(f), K(f)U=ml.min(-1).100 ml(-1).mmHg(-1)]. Values were 3- to 4-fold lower towards the end of the second decade [4.69 (1.91-7.06) K(f)U]. Young mammals are known to have a larger microvascular surface area per unit volume of skeletal muscle than adults. During development the proportion of developing vessels is greater. Moreover, the novel microvessels are known to be more permeable to water and plasma proteins than when mature. These factors may explain why children more readily develop hypovolaemic shock than adults in dengue haemorrhagic fever and other conditions characterized by increased microvascular permeability.     

Pharmacokinetics of oral and intravenous ofloxacin in children with multidrug-resistant typhoid fever.

The pharmacokinetics of oral and intravenous ofloxacin (7.5 mg.kg of body weight-1 given over 30 min) were studied in an open crossover study of 17 Vietnamese children, aged between 5 and 14 years, with acute uncomplicated typhoid fever. Following oral administration, the median (95% confidence interval [CI]) time to peak concentration of ofloxacin in serum (Cmax) was 1.7 h (1.4 to 1.9 h) and the mean (95% CI) Cmax was 5.5 mg.liter-1 (4.7 to 6.3 mg.liter-1) compared with a Cmax of 8.7 mg.liter-1 (7.6 to 9.7 mg.liter-1) following the intravenous infusion. The median (95% CI) total apparent volume of distribution following the first intravenous dose, 1.35 liter.kg-1 (1.17 to 1.73 liter.kg-1), was significantly larger than that following the second dose, 0.99 liter.kg-1 (0.86 to 1.17 liter.kg-1; P < 0.0005), although the estimates for systemic clearance were similar: 0.255 liter.kg-1 h-1 (0.147 to 0.325 liter.kg-1 h-1) compared with 0.172 liter.kg-1 h-1 (0.127 to 0.292 liter.kg-1 h-1; P = 0.14). The mean residence times (95% CI) following intravenous and oral administration were similar: 5.24 h (4.84 to 6.58 h) and 6.24 h (5.32 to 7.85 h), respectively. The mean (95% CI) oral bioavailability was 91% (74 to 109%). The peak concentrations in serum were 10 to 100 times higher than the maximum MICs for ofloxacin against multidrug-resistant Salmonella typhi isolated in this area. Although the systemic clearance values were higher than those reported previously for adults, these data overall suggest that weight-or area-adjusted dose regimens for the treatment of typhoid in older children should be the same as those for adults.     

Detection of antibodies to Trypanosoma cruzi among blood donors in the southwestern and western United States. II. Evaluation of a supplemental enzyme immunoassay and radioimmunoprecipitation assay for confirmation of seroreactivity

BACKGROUND: Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi, is endemic to Latin America and may be transmitted in the United States via blood donated by infected immigrants. Blood- borne pathogens such as T. cruzi require supplemental testing for confirmation of seroreactivity. STUDY DESIGN AND METHODS: A study was undertaken to determine an optimal scheme for confirmation of seroreactivity in repeatedly reactive samples identified by the Chagas antibody enzyme immunoassay (EIA). The procedure for initial confirmation involves three purified antigens coated onto three separate polystyrene beads and uses an EIA format. If the sample is reactive with two of three or three of three antigens, it is confirmed as seroreactive. If none or one of three beads is reactive, the sample is indeterminate and subjected to a radioimmunoprecipitation assay (RIPA). The RIPA must demonstrate characteristic bands at 32, 34, and 90 kDa. RESULTS: When tested with sera from persons with potentially cross-reactive diseases (n = 39) or against a presumed negative population from southeast Wisconsin (n = 289), the confirmatory EIA had a specificity of 100 percent. Sensitivity was 100 percent (28/28) with xenodiagnosis-positive sera and 97.6 percent (80/82) with chagasic sera from Latin America. The RIPA showed a specificity of 100 percent in EIA- nonreactive samples (n = 100) and a sensitivity of 100 percent with both xenodiagnosis-positive (28/28) and chagasic (82/82) sera. CONCLUSION: The confirmatory EIA and the RIPA together provide a highly specific and sensitive means of confirming seroreactivity for antibodies to T. cruzi.     

Current concepts in stereotactic radiosurgery - a neurosurgical and radiooncological point of view

Stereotactic radiosurgery is related to the history of "radiotherapy" and "stereotactic neurosurgery". The concepts for neurosurgeons and radiooncologists have been changed during the last decade and have also transformed neurosurgery. The gamma knife and the stereotactically modified linear accelerator (LINAC) are radiosurgical equipments to treat predetermined intracranial targets through the intact skull without damaging the surrounding normal brain tissue. These technical developments allow a more precise intracranial lesion control and offer even more conformal dose plans for irregularly shaped lesions. Histological determination by stereotactic biopsy remains the basis for any otherwise undefined intracranial lesion. As a minimal approach, it allows functional preservation, low risk and high sensitivity. Long-term results have been published for various indications. The impact of radiosurgery is presented for the management of gliomas, metastases, brain stem lesions, benign tumours and vascular malformations and selected functional disorders such as trigeminal neuralgia. In AVM''s it can be performed as part of a multimodality strategy including resection or endovascular embolisation. Finally, the technological advances in radiation oncology as well as stereotactic neurosurgery have led to significant improvements in radiosurgical treatment opportunities. Novel indications are currently under investigation. The combination of both, the neurosurgical and the radiooncological expertise, will help to minimize the risk for the patient while achieving a greater treatment success.     

Cerebral calpain in fatal falciparum malaria

Disruption of axonal transport may represent a final common pathway leading to neurological dysfunction in cerebral malaria (CM). Calpains are calcium (Ca2+)-activated cysteine proteases which have been implicated in axonal injury in neurological diseases of various aetiologies. In this study we examined the association between mu- and m-calpain, the specific inhibitor calpastatin, and axonal injury in post mortem brain tissue from patients who died from severe malaria. Calpains were associated with axons labelled for the beta-amyloid precursor protein that detects impaired axonal transport. Elevated levels of calpastatin were rarely observed in injured axons. There were increased numbers of neurones with mu-calpain in the nuclear compartment in severe malaria cases compared with non-neurological controls, and increased numbers of glia with nuclear mu-calpain in CM patients compared with non-CM malaria cases and non-neurological controls. There was marked redistribution of calpastatin in the sequestered Plasmodium falciparum-infected erythrocytes. Responses specific to malaria infection were ascertained following analysis of brain samples from fatal cases with acute axonal injury, HIV encephalitis, and progressive multifocal leucoencephalopathy. Our findings implicate a role for calpains in the modulation of disease progression in CM.     

Oral health status of adults in Southern Vietnam - a cross-sectional epidemiological study

Background

Dental caries is one of the primary causes of tooth loss among adults. It is estimated to affect a majority of Americans aged 55 and older, with a disproportionately higher burden in disadvantaged populations. Although a number of treatments are currently in use for caries prevention in adults, evidence for their efficacy and effectiveness is limited.

Methods/Design

The Prevention of Adult Caries Study (PACS) is a multicenter, placebo-controlled, double-blind, randomized clinical trial of the efficacy of a chlorhexidine (10% w/v) dental coating in preventing adult caries. Participants (n = 983) were recruited from four different dental delivery systems serving four diverse communities, including one American Indian population, and were randomized to receive either chlorhexidine or a placebo treatment. The primary outcome is the net caries increment (including non-cavitated lesions) from baseline to 13 months of follow-up. A cost-effectiveness analysis also will be considered.

Discussion

This new dental treatment, if efficacious and approved for use by the Food and Drug Administration (FDA), would become a new in-office, anti-microbial agent for the prevention of adult caries in the United States.

Trial Registration Number

NCT00357877