Digital radiography of subtle pulmonary abnormalities: an ROC study of the effect of pixel size on observer performance

Forty conventional radiographs with examples of mild interstitial infiltrates and subtle pneumothoraces and 40 normal studies of the chest were selected and digitized, with pixel sizes of 1.0, 0.5, 0.2, and 0.1 mm. Observer performance tests were carried out using receiver operating characteristic analysis. Conventional radiographs and digitized images were compared. The results indicate that, in such cases, diagnostic accuracy increases significantly as the pixel size is reduced, at least to the 0.1-mm level. We conclude that, for digital systems using screen-film or similar image receptors, use of a pixel size substantially larger than 0.1 mm may result in some loss of diagnostic accuracy.     

登革病毒感染蚊虫后几个器官敏感性的比较

以浓度为4×10~8TCID_(50)/ml和4×10～5TCID_(50)/ml的病毒液经口感染,4×10~8TCID_(50)/ml和4×10~2TCID_(50)/ml病毒液经胸接种白纹伊蚊(Aedes albopictus)。结果表明1、脑和神经节感染率相同,2、神经系统对病毒敏感性较涎腺高。     

Sensitisation to Swine Leukocyte Antigens in Patients with Broadly Reactive HLA Specific Antibodies

We have previously shown that IgG HLA specific antibodies in the sera of highly sensitised patients awaiting renal transplantation can cross-react with swine leukocyte antigens (SLA). In this study we determined the frequency of patient serum IgG HLA specific antibody binding to a porcine lymphocyte panel and the likelihood of locating a cross-match negative pig donor for sensitised patients. Serum samples (n = 82) were obtained from 35 sensitised [current IgG panel reactive antibodies (PRA) > 10%] and seven nonsensitised patients awaiting renal transplantation at Addenbrooke's Hospital, Cambridge, UK. Fifty sera had IgG HLA specific PRA of 11-84%, 20 had IgG PRA of >84% and 12 had 0% PRA (negative controls). Sera were absorbed with porcine erythrocytes to remove xenoreactive natural antibodies and tested for cross-reactive IgG HLA specific antibody binding by flow cytometry against a panel of porcine lymphocytes obtained from 23 human decay accelerating factor (hDAF) transgenic pigs. A total of 1,884 cross-match combinations were tested and 369 (20%) gave a positive porcine lymphocyte cross-match. For sera from sensitised patients with IgG PRA (11-64%), only 6 of 805 (0.75%) cross-match tests were positive. In contrast, for sera from patients with high IgG PRA (>64%), 363 of 805 (45%) cross-match tests were positive (p < 0.0001). There was no difference in the frequency of positive cross-matches between patient sera with IgG PRA 65-84% and highly sensitised patient sera with IgG PRA 85-100% [156/345 (45%) vs. 207/460 (45%)]. This study demonstrates that only patient sera with broadly reactive IgG HLA specific PRA (>64%) cross-react with porcine lymphocytes. If future clinical trials of xenotransplantation are undertaken, it may be of value to select a cross-match-negative pig organ donor for such patients.     

Lack of spontaneous activity of cutaneous spinal dorsal horn neurons in awake, drug-free, spinally transected cats

Extracellular single-unit activity was recorded from neurons with cutaneous input in the dorsal horn of the spinal cord (L4-L6) of awake, drug-free cats before (for several weeks) and after (day 1 through day 7) cord transection (T12). The spontaneous activity of the neurons was minimal or nonexistent in both recording conditions. The lack of spontaneous activity following spinal cord transection contrasts sharply with activity recorded in acute spinal-cord transected preparations in which high rates of spontaneous activity have been reported. This discrepancy may reflect an important difference between the chronic, awake, drug-free and acute preparations.     

Characteristics of different isolates of Schistosoma japonicum from China in the final hosts

The present paper deals with the susceptibility of common laboratory animals, such as mouse, rat, hamster, jird, rabbit and rhesus monkey, to infection with different isolates of Schistosoma japonicum in the mainland of China under laboratory conditions. With the exception of the rat, all the animals under study were permissive hosts for different isolates though their worm recovery rates varied. The mean body length of pair-worms of the Yunnan isolate was considerably smaller than that of the Anhui, Hubei, Guangxi and Sichuan isolates, and the percentage of male specimens with 7 testes in the Yunnan isolate was also significantly less than that in the other 4 isolates. Judging from the egg index (width/length x 100), the eggs of the Sichuan isolate were broad and short in shape, giving a high index; those of Guangxi and Hubei isolates were oblong, giving the lowest index; the other two isolates from Yunnan and Anhui, lay between these two extremes. The mean prepatent periods were longer in mice, hamsters and rhesus monkeys infected with Yunnan and Guangxi isolates, than those with Sichuan isolate. A dendrogram of the 5 isolates of S. japonicum was constructed on the basis of similarity coefficients by means of fuzzy cluster analysis on the biological characters mentioned above. Our results provide evidence of the existence of different strains of S. japonicum in the mainland of China as shown by comparative studies of their characteristics in the final hosts.     

Electron microscopic evidence for the association of M 2 protein with the influenza virion

Summary Immunogold electron microscopy revealed that site-specific antibodies elicited by a synthetic peptide representing the N-terminal sequence (residues 2–10) of influenza virus M 2 protein were capable of binding to the surface of virions. Antibody binding was observed with two human influenza virus strains but not with an avian virus strain which has amino acid substitutions in the appropriate sequence of M 2. These results provide direct evidence for the presence of M 2 in the influenza virion.     

必须重视中药新药质量标准和制剂稳定性的研究

从审评工作的角度,提出我国要研制出在世界上有竞争力、安全有效的中药新药,必须重视中药新药质量标准和制剂稳定性的研究。同时,应加强新药审批办法的学习,以提高中药新药的申报水平。     

Comparison of p53 expression in proximal and distal gastric cancer: Histopathologic correlation and prognostic significance

Background: The overexpression of p53 has been found to be correlated with prognosis of some carcinomas, including gastric cancer, but no studies have reported on its relationship to the location of gastric cancer. In the present study, we compared the p53 expression of proximal and distal gastric cancer concerning histopathology and prognosis. Methods: A total of 170 tumors in the patients with proximal (80 cases) and distal (90 cases) gastric cancer were studied by immunohistochemical methods. Results: p53 immunopositivity was detected in 28.8% of all tumors. The p53-positive expression in proximal gastric cancer was higher than in distal gastric cancer (38.8% vs. 20.0%, p<0.05). A 5-year survival analysis showed that there is no significant difference between tumors that are p53 positive and p53 negative. No correlation was found between p53 expression and histopathology of gastric cancer. Conclusion: p53 nuclear staining is not useful as a prognostic indicator or as a parameter in gastric cancer.     

抗体阴性重症肌无力发病与凝集素之间关系研究

借助研究抗体阴性重症肌无力（ＭＧ）发病与凝集素之间的关系，以阐明其发病过程是否与凝集素有关。方法观察伴刀豆球蛋白Ａ（ＣｏｎＡ）和麦胚凝集素（Ｔｒｉｔｉｃｕｍ）及其凝集素－糖复合物对ＴＥ６７１细胞表达的乙酰胆碱受体（ＡＣｈＲ）功能的作用，以及对α－ＢｕＴｘ结合试验的影响。结果有两种凝集素对ＡＣｈＲ功能均有抑制作用，抑制率（％）分别为５４±１４（ｎ＝１１）和４７±１６（ｎ＝１０），此作用可被３种糖抑制，抑制率（％）分别为：９５±５（ｎ＝５）和８４±８（ｎ＝５）；６９±６（ｎ＝４）和６５±５（ｎ＝４）；３９±４（ｎ＝５）和５７±６（ｎ＝５）；ＣｏｎＡ抑制α－ＢｕＴｘ结合试验，而Ｔｒｉｔｉｃｕｍ则不能。结论Ｔｒｉｔｉｃｕｍ和抗体阴性ＭＧ患者非ＩｇＧ部分对ＡＣｈＲ功能和α－ＢｕＴｘ结合试验的作用类同或一致，表明抗体阴性ＭＧ患者非ＩｇＧ部分中的内源性Ｔｒｉｔｉｃｕｍ样糖蛋白在其发病过程中起重要作用。