体外诱导骨髓间充质干细胞向神经元样细胞分化的机制研究

目的体外诱导成人骨髓间充质干细胞(MSCs)向神经元样细胞分化,并探讨分化过程中多效蛋白(PTN)mRNA的表达,以了解MSCs向神经元样细胞分化的特性和机制。方法密度梯度离心加贴壁培养法分离成人MSCs,原代和传代培养。取第6代MSCs设对照和试验组进行诱导,诱导后30 min至3 d,观察细胞形态并计数。免疫细胞化学法和反转录-聚合酶链反应(RT-PCR)法测定分化后细胞神经细胞特异性表面标志神经元烯醇化酶(NSE)、微管相关蛋白(MAP)-2,胶原酸性蛋白(GFAP)和诱导前、诱导后12 h PTN mRNA的表达。结果接种24 h后MSCs开始贴壁,呈圆形或椭圆形。3 d后可见梭状细胞呈集落状生长,10～14 d融合。第5～6代时呈现较均一的成纤维细胞样形态。诱导后胞体向胞核收缩;出现双极及多极细胞。12 h变形细胞增多,细长突起相互连接。24 h后变形细胞增多不明显。诱导后12 h大部分细胞表达NSE(64.79±0.07)%、MAP-2(60.05±0.09)%,未检测到GFAP的表达,RT-PCR半定量检测有NSE mRNA的表达(0.66±0.15)。实验组诱导后12 h细胞有PTN mRNA的表达(0.689±0.017)。结论建立了稳定的成人MSCs培养增殖体系,MSCs可体外诱导分化为神经元样细胞,在分化过程中有外观形态变化和特异性标志物NSE和MAP-2的表达,同时有PTN mRNA的表达,提示PTN可能参与调控了MSCs向神经元样细胞的分化。     

Mechanism of human accommodation as analyzed by nonlinear finite element analysis

Results of nonlinear finite element analysis support the Schachar theory of accommodation and demonstrate that the long-held Helmholtz theory of accommodation is impossible.     

Chagas' disease diagnosis: evaluation of several tests in blood bank screening

Blood transfusion is one of the principal routes of transmission of Chagas' disease, a major endemic disease in Latin America. Methods for blood screening are not accurate and may yield false results that lead to high social and economic costs. This study compares two methods of diagnosing Chagas' disease (indirect immunofluorescence and hemagglutination) and several enzyme-linked immunosorbent assays (ELISAs) with regard to specificity and sensitivity, by using human sera with known serologic and parasitologic characteristics, as well as samples with discrepant results on conventional serologic tests. An ELISA using recombinant antigens showed no cross-reactivity with sera that were positive for other diseases. All evaluated ELISAs performed well, and their use may lead to a reduction of more than 50 percent in the number of discordant sera. Further improvements are needed in view of the complexity of the serologic diagnosis of Chagas' disease.     

Satellite and Mobile Wireless Transmission of Focused Assessment with Sonography in Trauma

Objectives: Focused assessment with sonography in trauma (FAST) can define life‐threatening injuries in austere settings with remote real‐time review by experienced physicians. This study evaluates vest‐mounted microwave, satellite, and LifeLink communications technology for image clarity and diagnostic accuracy during remote transmission of FAST examinations. Methods: Using a SonoSite, FAST was obtained on three patients with pericardial and intraperitoneal effusions and two control subjects in a remotely located U.S. Army Combat Support Hospital. A miniature vest‐mounted video transmitter attached to the SonoSite sent wireless ultrasound video 20 m to a receiving antenna. The signal was then transferred over VSAT satellite systems at 512 kilobaud per second (kbps), INMARSAT satellite systems at 64 kbps, and over LifeLink on a moving ambulance through a metropolitan wireless traffic–management network. Clarity and absence or presence of effusions were recorded by 15 staff emergency physicians. Results: Average sensitivity, specificity, and accuracy were 87% (95% confidence interval [CI] = 79% to 95%), 85% (95% CI = 81% to 89%), and 86% (95% CI = 82% to 90%) for the Premier Wireless Vest; 98% (95% CI = 97% to 99%), 83% (95% CI = 75% to 91%), and 86% (95% CI = 82% to 90%) for VSAT; 95% (95% CI = 94% to 96%), 70% (95% CI = 58% to 82%), and 75% (95% CI = 70% to 80%) for INMARSAT; and 82% (95% CI = 73% to 91%), 83% (95% CI = 74% to 92%), and 82% (95% CI = 78% to 86%) for LifeLink with clarity of 3.0 (95% CI = 2.7 to 3.3), 2.9 (95% CI = 2.6 to 3.2), 1.3 (95% CI = 1.2 to 1.4), and 2.1 (95% CI = 1.8 to 2.4), respectively. Conclusions: Accuracy correlated with clarity. Roaming vest transmission of FAST provides interpretable, diagnostic imagery at the distances used in this study. VSAT provided the best clarity and diagnostic value with the lighter, more portable INMARSAT serving a lesser role for remote clinical interpretation. LifeLink performed well, and further infrastructure improvements may increase clarity and accuracy.     

Awareness of HIV/AIDS among primary school pupils in north central region of Nigeria

ObjectiveTo determine the knowledge of HIV/AIDS among primary school pupils in north central area of Nigeria.Methods2000 randomly selected primary school pupils in and around eastern part of Idoma area of Benue state were interviewed using an open-ended questionnaire. Data analysis was done with EPI-INFO 2000. The Chi-square test was used for statistical analysis and the 0.05 level of significance was adopted.ResultsA totle of 1010 males and 990 females at ages between five and sixteen years were drawn from 10 primary schools in the area. Pupils in the higher classes were more knowledgeable and sex difference was not statistically significant. Certain misconceptions were noted.ConclusionsThere is need for health education for all cadres of primary school pupils in the area, which will increase the awareness of the disease.     

Successful treatment of Fusarium keratitis with cornea transplantation and topical and systemic voriconazole

A case of invasive Fusarium keratitis in a previously healthy male patient was treated successfully with cornea transplantation and systemic and topical voriconazole after treatment failure with topical amphotericin B and systemic itraconazole. Topical voriconazole was well tolerated, and, in conjunction with the oral administration, it resulted in a high level of the drug in the anterior chamber of the eye (which was 160% of the plasma drug level).     

A novel homozygous mutation at the GAA gene in Mexicans with early-onset Pompe disease

Glycogen-storage disease type II, also named Pompe disease, is caused by the deficiency of the enzyme acid alpha-glucosidase, which originates lysosomal glycogen accumulation leading to progressive neuromuscular damage. Early-onset Pompe disease shows a debilitating and frequently fulminating course. To date, more than 300 mutations have been described; the majority of them are unique to each affected individual. Most early-onset phenotypes are associated with frameshift mutations leading to a truncated alpha-glucosidase protein with loss of function. Founder effects are responsible from many cases from few highprevalence world regions. Herein we described two apparently unrelated cases affected with classical early-onset Pompe disease, both pertaining to a small region from Central Mexico (the State of San Luis Potosí), the same novel homozygous frameshift mutation at gene GAA (c.1987delC) was demonstrated in both cases. This GAA gene deletion implies a change of glutamine to serine at codon 663, and a new reading frame that ends after 33 base pairs, which leads to the translation of a truncated protein. This report contributes to widen the knowledge on the effect of pathogenic mutations in Pompe disease. Here we postulate the existence of a founder effect.Key words: Early-onset Pompe disease, Acid maltase deficiency, Founder effectGlycogen storage disease type II (Online Mendelian Inheritance in Man, OMIM, accession number 232300), also called Pompe disease, was described by Johannes C. Pompe in 1932. The disorder is caused by a deficiency of the enzyme acid alpha-glucosidase (acid maltase, EC 3.2.1.20, Swiss) which originates lysosomal glycogen accumulation leading to lysosomal swelling, cellular damage and dysfunction (1-3). Affected individuals develop progressive neuromuscular damage, showing a debilitating and frequently fulminating course on the classical, early-onset type of the disease. Other main findings are hypertrophic cardiomyopathy, hypotonia, hepatomegaly, macroglossia, feeding problems and breath difficulty. Currently it is recognized that the late form of Pompe disease has a very variable phenotype that can be confused with a wide range of neuromuscular, pulmonary and cardiovascular diseases with mild, moderate or severe symptoms that present either alone or combined (4-6).Pompe disease has an autosomal recessive inheritance and it is caused by more than 300 mutations that occur all over the gene coding for acid alpha-glucosidase (GAA) located at locus 17q25.2q25.3. The molecular phenomenon responsible of the different types of clinical expression occur by the presence of two either homozygous or compound heterozygous pathogenic mutations in early-onset Pompe cases, whereas late-onset Pompe have one variant and one pathogenic mutation (7). The majority of disease-causing mutations are unique; nonetheless, relatively frequent mutations have been described in certain populations with a possible founder effect traced from the original mutated carrier to the newly occurring cases. Affected cases have been described worldwide with a few high-prevalence regions like South-Africa, Taiwan and Holland (1, 8-10).Herein, we described two unrelated cases affected with classical early-onset Pompe disease, both pertaining to the same small Mexican region, with the same novel homozygous frameshift mutation at gene GAA (c.1987delC), identified by complete gene sequencing.