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。     

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.     

Aperture modulated arc therapy

We show that it is possible to translate an intensity modulated radiation therapy (IMRT) treatment plan and deliver it as a single arc. This technique is referred to in this paper as aperture modulation arc therapy (AMAT). During this arc, the MLC leaves do not conform to the projection of the target PTV and the machine output of the accelerator has a constant value. Dose was calculated using the CORVUS 4.0 IMRT system, which uses a pencil beam dose algorithm, and treatments were delivered using a Varian 2100C/D Clinac. Results are presented for a head and neck and a prostate case, showing the equivalence of the IMRT and the translated AMAT delivery. For a prostate AMAT delivery, coronal plane film dose for the IMRT and AMAT deliveries agreed within 7.19 +/- 6.62%. For a meningioma the coronal plane dose distributions were similar to a value of 4.6 +/- 6.62%. Dose to the isocentre was measured as being within 2% of the planned value in both cases.     

Glycoconjugate metabolism in a cystic fibrosis knockout mouse model

Cystic fibrosis knockout mice (cftr(-/-)) die prematurely of obstruction of the intestine which may result from accumulation of dehydrated glycoconjugate-containing mucus. We noted an increase in the specific activity of [(14)C]glucosamine-labeled high-molecular weight glycoconjugates, probably mucin, in the lumen of the intestine of cftr(-/-) (homozygous) mice compared to cftr(+/+) (wild-type) and cftr(+/-) (heterozygous) mice and a decrease in the turnover of glycoconjugates of several organs of the cftr(-/-) mice. No difference in the anionic composition of secreted intestinal glycoconjugates was detected and no difference in the amount of mucin 1 (Muc1) was found in the small intestine, colon, pancreas, and lungs of the different genotypes. In addition, the spleen of the cftr(-/-) mice was significantly smaller than that of control mice and the small intestine and colon were, respectively, longer and shorter compared to control mice. These results indicate modified glycoconjugate metabolism in cystic fibrosis knockout mice and morphologic changes to the spleen and intestine where the latter modifications are possibly related to the intestinal malabsorption associated with cystic fibrosis.     

IBA损伤老化鼠脑Meynert核的AD模型动物研究

目的研究定位损伤脑胆碱能系Alzheimer病(AD)模型大鼠学习能力及相关脑神经肽免疫组化改变.方法用兴奋性毒素鹅膏蕈氨酸(IBA)定位损伤大鼠脑右侧Meynert核,观察模型动物学习能力改变(Y型迷宫法),并用分光光度法和免疫组化染色法观察动物脑胆碱酯酶(AchE)活性和皮层及海马β-淀粉样肽前体(β-APP)、生长抑素(SOM)及P物质(SP)的表达情况.结果模型组老化大鼠经损伤后,学习能力及脑AchE活性显著低于对照组(P均＜0.05).β-APP在额叶皮层和海马的表达均升高,而S()M表达则显著减少,用IBA及β-AP25-35同时损伤鼠脑时,可显示脑皮质区SP表达增加(P均＜0. 01).单独用IBA注射无效.结论IBA损伤老化大鼠脑Meynert核建立的动物模型,显示胆碱能系统损伤,学习能力障碍,β-APP过表达而神经肽SOM表达降低,一定条件下SP表达增加,与AD病人某些临床和病理特征基本一致.