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.     

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.     

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     

Parathyroid hormone response to hypocalcemia in hemodialysis patients with osteomalacia

The parathyroid hormone response to hypocalcemia was investigated in hemodialysis patients with osteomalacia and compared to those with osteitis fibrosa. Hypocalcemia was induced during hemodialysis by employing a dialysate devoid of calcium. Patients with osteomalacia had a blunted maximum amino terminal parathyroid hormone response (+/- SD) (0.39 +/- 0.33 vs. 0.87 +/- 0.53 ng/ml, P less than 0.05) and maximum carboxy terminal parathyroid hormone response (+/- SD) (0.36 +/- 0.20 vs. 0.84 +/- 0.47, P less than 0.02) to hypocalcemia. The decline in plasma calcium was greater in patients with osteomalacia at 90 (P less than 0.05), 120 (P less than 0.01), and 150 min (P less than 0.01). In osteomalacia patients the surface density of histologically detectable trabecular bone aluminum correlated directly with the percent relative osteoid volume (P less than 0.005) and inversely with the maximum amino terminal parathyroid hormone response to hypocalcemia (P less than 0.025). These results suggest that hemodialysis patients with osteomalacia have diminished secretion of parathyroid hormone and a decreased ability to restore plasma calcium homeostasis during hypocalcemia.