A case of vertical transmission of hepatitis A virus infection

We present a case of hepatitis A infection in a 2.5-month-old male who became icteric after 18 d of birth. The diagnosis of hepatitis A was made by compatible clinical symptoms, laboratory results and liver biopsy showing evidence of hepatitis, and confirmed by detection of anti-HAV IgM antibodies. Because the mother had an acute icteric hepatitis A 1 week before delivery, and the viraemic phase of hepatitis A infection is very short, approximately 7 d, we suggest that the infant was infected by his mother, before birth.     

Detector for dual-energy digital radiography

A detection scheme is described that allows one to accomplish dual-energy scanned projection digital radiography without switching the x-ray tube voltage. The method employs a high/low atomic number detector sandwich that simultaneously separates the x-ray beam transmitted by the patient into low and high energy components. To test the method, the response of a scanning linear array of energy-sensitive detectors was simulated, and bone and soft tissue images of an anthropomorphic chest phantom were obtained at 140 kVp. These were compared with similar images obtained by switching the x-ray tube voltage from 80 kVp to a heavily filtered 140 kVp. For comparable entrance skin exposures, the dual-energy detector images required a lower tube load and resulted in higher noise levels. The latter is attributable to the fact that the separation in energy between the high and low energy components is smaller with the dual-energy detector than with the voltage switching technique, and to misregistration problems associated with the simulation methodology. A detector design is also discussed that would result in improved energy separation and lower noise levels. In view of this possibility and the tube loading advantage, the method looks promising for digital scanned projection radiography.     

葛根素对缺血再灌注损伤心肌组织热休克蛋白70表达的影响

目的:葛根素注射液已初步被证实具有抗氧化自由基,减轻缺血再灌注后心肌超微结构损伤的药理作用.观察心肌缺血再灌注损伤时热休克蛋白70的表达变化及葛根素对其的影响,寻求其新的心肌保护机制.方法:实验于2005-03/2006-04在江西省心血管病研究所完成,动物实验方法符合动物伦理学要求.①实验材料及分组:选用健康雄性SD大鼠48只,按随机数字表法分为缺血再灌注模型组及葛根素组(n=24),每组再根据再灌注时间不同分为缺血20min再灌注0.5,4及8h组(n=8).②实验方法:结扎大鼠左冠状动脉前降支建立心肌缺血/再灌注模型,葛根素组在结扎冠状动脉前降支前10min经腹腔给予葛根素注射液50mg/kg;缺血再灌注模型组则给予等容量的生理盐水.③实验评估:于再灌注后0.5,4,8h各时相点,应用链霉抗生物素蛋白-过氧化物酶法检测心肌热休克蛋白70含量;采用分光光度法检测血清髓过氧化物酶活性;应用透射电镜观察心肌组织超微结构.结果:48只大鼠全部进入结果分析.①热休克蛋白70主要在心肌细胞的胞浆表达,以细胞核的核周最为明显,细胞核很少表达.②随着再灌注时间延长心肌热休克蛋白70含量表达逐渐增强,心肌缺血再灌注后0.5,4,8h葛根素组大鼠心肌热休克蛋白70含量均显著高于缺血再灌注模型组(P＜0.05～0.01).③随着再灌注时间延长髓过氧化物酶活性呈现下降趋势,心肌缺血再灌注后0.5,4,8h葛根素组大鼠血清髓过氧化物酶活性均显著低于缺血再灌注模型组(P＜0.01).④缺血再灌注模型组大鼠心肌纤维排列不规则,部分发生断裂、溶解;线粒体排列紊乱,明显肿胀.葛根素组大鼠心肌纤维排列规则,结构完整;线粒体排列整齐.结论:葛根素能明显减轻心肌缺血再灌注损伤,其心肌保护途径可能是通过上调热休克蛋白70表达、降低血清髓过氧化物酶活性来实现的.     

携带半乳糖苷酶报告基因重组腺相关病毒体内转染骨组织的实验观察

目的:腺相关病毒载体因具有安全性好、免疫源性低、能感染分裂和非分裂细胞且能介导外源基因稳定长期表达等优点而备受瞩目,是最有希望应用于临床的病毒类载体。观察携带半乳糖苷酶报告基因的重组腺相关病毒(rAAV-LacZ)体内转染骨组织的效果。方法:实验于2005-01/2006-01在北京大学医学部第三医院和皖南医学院弋矶山医院骨科实验室完成。实验材料:8周龄雄性SD大鼠8只,体质量220g左右。rAAV-LacZ载体(本元正阳公司,病毒滴度为6×1012v·g/mL);Ⅰ型胶原海绵载体(上海其胜公司)。实验分组:将大鼠随机分为实验组和对照组,每组4只。实验方法:实验组4只大鼠在胫骨前外侧做骨缺损槽后,将滴有6×1011v·g病毒量的rAAV-LacZ和Ⅰ型胶原载体复合物植入骨缺损槽;对照组4只大鼠仅在胫骨骨缺损槽内植入Ⅰ型胶原载体。实验评估:①手术后6周取材行x-gal染色后,分别行标本大体病理观察和组织学观察以了解β-半乳糖苷酶特异表达的情况。②同时提取实验部位以远器官肝和心脏组织RNA,反转录-聚合酶链反应检测这些部位有无β-半乳糖苷酶特异表达。结果:8只SD大鼠均进入结果分析。①大体病理观察结果:实验组动物胫骨骨缺损处取材经x-gal染色后可见骨质蓝染,即有特异性β-半乳糖苷酶表达,而骨缺损临近处肌肉也表达β-半乳糖苷酶,Ⅰ型胶原载体植入部位以远的骨质和肌肉则没有特异性β-半乳糖苷酶的表达。②组织学观察结果:实验组骨缺损处肌肉肌纤维特异性表达β-半乳糖苷酶且没有明显的淋巴细胞局部浸润。蓝染的骨皮质切片显示骨陷窝内的骨细胞特异性表达β-半乳糖苷酶。对照组则没有实验组上述特异性β-半乳糖苷酶的表达。③反转录-聚合酶链反应结果:实验组实验部位有特异性β-半乳糖苷酶的表达,而其以远的心、肝器官内没有特异性β-半乳糖苷酶的表达。而对照组实验部位和实验部位以远的心、肝器官内均没有特异性β-半乳糖苷酶的表达。结论:腺相关病毒载体直接注射到骨缺损和骨折部位可以有效转染骨和临近肌肉组织,并能长期(6周)表达所携带的外源基因,具有一定的安全性。     

Thyrotoxic periodic paralysis in a Chinese population

We retrospectively evaluated the characteristics of adult patients admitted with thyrotoxic hypokalaemic periodic paralysis in Hong Kong. From 1984 to 1993, 45 Chinese adult patients were admitted with acute limb weakness, plasma potassium ⩽3.5 mmol/l and thyrotoxicosis confirmed by laboratory investigations. All but one were male. Seventy-five percent of attacks occurred between 9pm and 9am. Half of the attacks occurred between July and October (49.1%), most commonly in August (20%). Mean (+SEM) plasma potassium on admission was 2.17 ± 0.08 mmol/l (range 1.1-3.5). In 15 episodes (27.3%), plasma potassium on recovery exceeded 5.0 mmol/l, while in three episodes (5.5%), potassium exceeded 6.0 mmol/l. No patient had a positive family history of thyrotoxic periodic paralysis. Only 28.9% had a known history of thyrotoxicosis before their first presentation with periodic paralysis. Twenty-seven (60%) had clinical evidence of thyrotoxicosis. Although all were biochemically thyrotoxic, 11.4% had only a mild degree of thyrotoxicosis (suppressed thyroid-stimulating hormone, high free thyroxine, but normal free triiodothyronine). One quarter of the patients had a normal erythrocyte zinc concentration, indicating either a short history of thyrotoxicosis or transient thyrotoxicosis. The diagnosis of thyrotoxic hypokalaemic paralysis should always be considered in Chinese patients with acute muscle weakness, especially in young males. Absence of clinical thyrotoxicosis does not exclude the diagnosis. Plasma potassium should be monitored carefully during treatment to prevent rebound hyperkalaemia.