cis-Acting packaging motifs of porcine adenovirus type 3

The cis-acting packaging domain is required for selective encapsidation of adenovirus DNA into preformed empty capsids late in the viral life cycle. Earlier, it was demonstrated that the cis-acting packaging domain of porcine adenovirus type (PAdV)-3 is located between nucleotide position (nt) 212 and 531 at the left end genome which contains six AT/GC rich motifs. Removal of packaging domain from left end to the right end of the genome produced a viable mutant virus suggesting that the identified cis-acting packaging domain represents the DNA sequences required for selective packaging of PAdV-3 DNA, whose position and orientation appear to be flexible. Here, by constructing and analyzing a panel of virus mutants carrying deletions or linker scanning mutations in AT/GC rich sequences, we examined the significance of the continuous A/T or G/C sequences individually in the viral packaging process. In contrast to consensus bipartite structure (5'-TTTGN8CG-3') described for most of packaging motifs of human adenovirus type 5 (HAdV-5), the packaging motifs I, II, III, and IV of PAdV-3 displayed a tripartite structure in which the continuous A/T nucleotides were flanked by G/C-rich sequences. Mutations in both continuous A/T nucleotides and its flanking GC-rich sequences reduced the packaging efficiency of mutants to varying degrees. In addition, although the continuous A/T sequences were present in all of the packaging motifs, their significance in the packaging process appears to vary within each packaging motif.     

Determination of Copy Number of rRNA Genes in Pneumocystis carinii f. sp. hominis

Differential PCR was performed to determine the copy number of rRNA genes in Pneumocystis carinii f. sp. hominis. Two different reference genes, thymidylate synthase (TS) and beta-tubulin (BTU) genes, were used. Primers for the internal transcribed spacer (ITS) region of nuclear rRNA genes and either the TS or BTU gene were mixed together to perform PCR on seven different bronchoalveolar lavage specimens from patients with P. carinii pneumonia. The radioactivity derived from the incorporated radioactive nucleotides of each PCR product band was then used to calculate the copy number of the ITS relative to that of the TS or BTU gene. The copy number ratio between the ITS and the TS gene was determined to be 0.8, and that between the ITS and the BTU gene was also 0.8. These results suggest that the ITS has the same copy number as the TS or BTU gene. Since the copy number of the TS or BTU gene is presumed to be 1, the results also suggest that P. carinii f. sp. hominis has only one copy of the ITS and thus one copy of the nuclear rRNA genes. Therefore, two types of ITS sequences derived from a specimen would indicate that the patient is infected by two types of P. carinii f. sp. hominis.     

Differential response to chemically altered polyethylene by activated mature human monocyte-derived macrophages

Macrophages and polyethylene (PE) particulate are currently recognized as being the two common denominators in the development of chronic inflammation, periprosthetic osteolysis, and subsequent implant failure. In this study, the effect of PE particulate surface chemistry on mature human monocyte-derived macrophage (MDM) function was investigated. Virgin high-density PE (HDPE: 4-10 microm) and HDPE oxidized by irradiation, thermal and chemical treatment were characterized by FT-IR and suspended in soluble type I collagen, which was subsequently solidified on glass coverslips. Human MDMs, derived from differentiating monocytes on polystyrene for 14 days, were trypsinized and cultured on collagen-particle substrata and collagen controls for 31 days. Analysis of conditioned media collected at 24h incubation showed a significantly higher level of IL-1beta secretion in virgin HDPE over oxidized HDPE or collagen controls, and a significant inhibition of IL-6 secretion in both virgin and oxidized samples. Esterase activity was increased in the medium at a significantly higher level in the virgin HDPE versus controls with the highest activity observed in oxidized HDPE at 31 days. These results illustrate the effect of PE particle surface chemistry (oxidation) on MDM cytokine secretion and esterase activity, and highlight the need to further investigate the potential of PE surface chemistry on modulating MDM function.     

耳穴静态电测量中的瞬变响应

耳穴电参数时变关系实验表明，在测量起始ｔ＜２τ时，因瞬变作用，电位Ｅ（ｔ）和压降Ｕ（ｔ）为瞬态响应，响应函数呈指数关系，特征参数为弛豫时间τ，τ≈ＲＣ；ｔ＞２τ时，为时变间期。电路分析给出数学描述，并与耳穴和模拟实验结果较相符。提示，时变特征应以ｔ＞２τ后提取，静态电测量时，采样应避开瞬变期，可提高准确性。该工作对正确鉴别时变性和特征提取，全面认识耳穴电特性具有重要意义。     

几种常用自陈主观幸福感量表在我国城市居民中的试用报告

本研究考察了几种常用自阵主观幸福感表在我国城市居民中的试用情况。表明，除情感平衡量表外，中国人幸福感量表，总体生活满意感量表和删改后夏普量表，对测量我国居民主观幸福感都有一定的实用或参考价值，但从根本上讲编订一套适用于我国居民的主观幸福感量表是很有必要的。     

一步温育EIA法检测HBsAg

本文报道用尼龙网为载体的抗ＨＢｓＡｇ抗体膜作免疫吸附剂用于酶联免疫测定，对检测ＨＢｓＡｇ的免疫反应程序和反应如酶标／抗原溶液配比量和温育反时间等进行了研究。结果得到一步温充ＥＩＡ法的灵敏度与二步温育ＥＩＡ法相比没有下降，检测时间由原来的约３ｈ缩短至约５０ｍｉｎ。     

盲人智能探路手杖的研究

本文介绍了盲人智能探路手杖的研究.该系统由单片机控制,采用两只超声波传感器的探测模式,对盲人行进路上的路况进行探测和分析,并针对不同的路况发出相应的提示信息,以达到辅助盲人安全行走的目的.