超声和微泡造影剂介导细胞基因转染的实验研究

目的 探讨低频超声对细胞基因转染的作用。方法 超声治疗仪频率1MHz，脉冲重复频率100Hz，占空系数20％。质粒DNA为含编码绿荧光蛋白的pEGFP。应用荧光显微镜和流式细胞仪评价细胞基因转染率，台盼蓝染色计算细胞成活率。选用C2C12、3T3-MDEI和CHO3种细胞系为研究对象，加入DNA后辐照不同声强、时间或加入超声造影剂，观察各条件下的细胞基因转染率和成活率。结果 ①超声介导的基因转染与声强和辐射时间有关，最佳剂量为1w／cm^2 20s；②同样超声剂量，较高的声强较早达到最大基因转染率；③较低剂量时，微泡造影剂可使超声介导的基因转染提高2～3倍并可显著提高最高基因转染率。结论 低频超声可介导细胞基因转染，基因转染率不但与超声辐射剂量有关，而且同样剂量时，高声强较早达到最大基因转染率，最佳剂量是1w／cm^2 20s。同时，微泡造影剂可提高超声介导基因转染的最高转染率。     

Hepatitis C and blood transfusion among children attending the Sickle Cell Clinic at Mulago Hospital,Uganda

Background

Hepatitis C virus (HCV) accounts for 90% of post-transfusion hepatitis. In Uganda, there has been limited research of prevalence of HCV among sickle cell anaemia (SS) patients, a group at risk for multiple transfusions.

Objectives

To establish prevalence of HCV infection and determine whether blood transfusion increases risk among SS patients.

Methods

244 SS patients aged 1–18 years were recruited by consecutive sampling. Socio-demographic, clinical and transfusion history was collected. Clinical examination done and blood tested for HCV by MEIA.

Results

244 children were recruited. Of these, 159 (65%) had a history of blood transfusion. Among the transfused, five patients were HCV positive. Four of these were over 12 years of age. Among patients with no history of transfusion, one patient aged 14 years was HCV positive. Risk of HCV was higher among the transfused OR 2.7(CI 0.31–24). Patients who received more than two units were more likely to be HCV positive (p=0.03).

Conclusions

HCV prevalence of 2.5% was low but higher than that reported by other investigators in Uganda. Blood transfusion was a major contributing factor in occurrence of HCV. Children who get repeated transfusions should be screened for Hepatitis C and screening of blood for HCV prior to transfusion would help reduce occurrence of the disease.     

Nodding syndrome in Mundri county,South Sudan: environmental,nutritional and infectious factors

Background

Nodding Syndrome is a seizure disorder of children in Mundri County, Western Equatoria, South Sudan. The disorder is reported to be spreading in South Sudan and northern Uganda.

Objective

To describe environmental, nutritional, infectious, and other factors that existed before and during the de novo 1991 appearance and subsequent increase in cases through 2001.

Methods

Household surveys, informant interviews, and case-control studies conducted in Lui town and Amadi village in 2001–2002 were supplemented in 2012 by informant interviews in Lui and Juba, South Sudan.

Results

Nodding Syndrome was associated with Onchocerca volvulus and Mansonella perstans infections, with food use of a variety of sorghum (serena) introduced as part of an emergency relief program, and was inversely associated with a history of measles infection. There was no evidence to suggest exposure to a manmade neurotoxic pollutant or chemical agent, other than chemically dressed seed intended for planting but used for food. Food use of cyanogenic plants was documented, and exposure to fungal contaminants could not be excluded.

Conclusion

Nodding Syndrome in South Sudan has an unknown etiology. Further research is recommended on the association of Nodding Syndrome with onchocerciasis/mansonelliasis and neurotoxins in plant materials used for food.     

超声微泡造影影像学及治疗作用的研究进展

包裹型气体微泡已经发展为临床应用的超声造影剂.微泡造影剂不仅已广泛用于血池和组织灌注显像,其治疗作用也日渐突显,例如溶栓和作为药物或基因的载体.造影剂微泡的平均直径小于红细胞直径,因而能够自由运行于微循环.微泡能将生物活性物质(例如药物或基因)结合在其内或其外膜表面,并将此物质转运于体内特定组织,例如将抗肿瘤药物转运并结合于特定肿瘤组织.靶向性微泡能将肽段等特定性配体结合于其微泡表面,这种特定性配体可特异性地与血管壁表达的受体相结合,微泡因而在靶组织区域积聚[1].     

Malignant jejunal strictures after Whipple procedure: stenting with large-bore tubes and use of combined transhepatic and peroral approach

Malignant strictures of the afferent jejunal limbs are difficult to treat. Surgical revision and chronic external drainage, two commonly used palliative procedures, have significant associated morbidity. A combined transhepatic and peroral approach was used to stent malignant jejunal strictures in two patients, allowing antegrade internal drainage of biliary and pancreatic secretions. Excellent palliation was achieved, and there were no associated complications.     

Antibody reactivity against human and guinea pig tissue transglutaminase in children with celiac disease

BACKGROUND: Highly discriminatory markers for celiac disease are needed to identify children with early mucosal lesions. The purposes of this study were to evaluate the clinical potential of circulating anti-tissue transglutaminase (tTG) immunoglobulin (Ig)A antibodies in the diagnosis of childhood celiac disease and to investigate the extent of autoreactivity of these antibodies. METHODS: Included in this retrospective study were samples from 22 children with biopsy-verified celiac disease, 23 control subjects with disease, and 22 healthy control subjects without any known gastrointestinal or inflammatory disorders. An enzyme-linked immunosorbent assay (ELISA) was used to measure the serum levels of IgA antibodies specific for human and guinea pig tTGs. All samples were also analyzed for antibodies to gliadin and endomysium (EMA). RESULTS: The concentrations of IgA specific for human and guinea pig tTGs correlated with the small intestinal villous structure and the serum levels of IgA EMA. The tTG ELISAs exhibited a high specificity and sensitivity for detection of untreated celiac disease. The human erythrocyte IgA tTG ELISA had the highest sensitivity (100%) and a specificity of 98%. The IgA EMA method had a sensitivity of 95% and the highest specificity (100%) of all tests. CONCLUSIONS: Our results provide additional support to the concept that anti-tTG IgA antibodies can be used as a highly discriminatory serologic marker for celiac disease and that measurements of these autoreactive antibodies may in the future be used as an alternative to the EMA test.     

Thymosin-α1, but not interferon-α, specifically inhibits anchorage-independent growth of hepatitis B viral transfected HepG2 cells

Background: Thymosin-α₁ is a biological response modifier that has been used clinically, alone and in combination with interferon-α for the treatment of chronic hepatitis B viral infection. Both immunomodulatory and immediate intracelluilar mechanisms have been postulated to explain the effect of these two agents on HBV-infected hepatocytes.Methods: In this study, hepatitis B transfected HepG2 hepatoblastoma cells (HepG2-Nu2), derived from 2.2.15 cells, were used as an in vitro model to determine the efficacy of thymosin-α₁ and interferon-α, individually and combined, a proliferation inhibitors of HBV-infected cells. For comparison, parental HepG2 cells and an SV40-transfected HepG2 cell line (HepG2P9T2) were also evaluated.Results: In a clonogenic soft agar assay, thymosin-α₁ inhibited the anchorage-independent growth of the HepG2-Nu2 cells by 40% compared with untreated controls, but did not inhibit parental HepG2 or HepG2P9T2 clonal growth. The response was dose dependent over concentrations spanning three log units. In comparison, 10 000 units/ml of interferon-α inhibited parental HepG2, HepG2-N4Z and HepG2P9T2 by 33%, 41% and 87%, respectively. The combination of thymosin-α₁ and interferon-α consistently inhibited HepG2-Nu2 clonal growth more effectively than either treatment alone, reaching maximum inhibition levels of 51%.Conclusions: Thymosin-α₁ specifically inhibits the tumorigenic growth of HBV-transfected HepG2 cells in contrast to the general inhibition displayed by interferon-α. This panel of cell lines may be an important resource for dissecting the mechanism by which thymosin, alone or in combination with other drugs, influences HBV-infected hepatocytes and/or HBV-associated carcinoma.