TT病毒核酸的检测

目的初步测定献血员、慢性乙型肝炎、慢性丙型肝炎及慢性非甲～戊型，非庚型肝炎患者中ＴＴ病毒的感染情况，分析不同ＴＴ病毒感染者血清中ＴＴ病毒开放读码框架２区部分基因序列。方法以套式聚合酶链反应测定ＴＴ病毒核酸，取献血员（ＴＸ２）、慢性乙型肝炎（ＴＸ３）、慢性丙型肝炎（ＴＸ４）及慢性非甲～戊型，非庚型肝炎患者（ＴＸ１）各１例ＴＴ病毒ＰＣＲ阳性产物，以双脱氧核苷酸链终止法测定核苷酸序列。结果检测２０例献血员、２９例慢性乙型肝炎、３１例慢性丙型肝炎及３２份慢性非甲～戊型，非庚型肝炎标本，ＴＴ病毒核酸阳性者分别占５．０％（１／２０）、６．９％（２／２９）、２９．０％（９／３１）和３４．４％（１１／３２）。与Ｎ２２克隆相比，ＴＸ１、ＴＸ２、ＴＸ３与ＴＸ４在核苷酸水平的同源性分别为９５．４１％、９８．４７％、９７．４５％和９７．９６％。结论本组献血员、慢性乙型肝炎、慢性丙型肝炎及慢性非甲～戊型，非庚型肝炎患者中均存在ＴＴ病毒感染者。从本组不同ＴＴ病毒感染者血清中分离出４株ＴＴ病毒序列，其开放读码框架２区部分基因序列高度保守     

Mitogenic properties of a bispecific single-chain Fv-Ig fusion generated from CD2-specific mAb to distinct epitopes [In Process Citation]

The combination of anti-CD2 mAb 9.6 and 9-1, specific for distinct epitopes, induces proliferation of resting human T cells. The mitogenic activity of this mAb mixture depends upon accessory cells and the 9-1 mAb Fc domain. To further study the functional properties of these mAb, their variable regions were cloned and expressed as monospecific single- chain Fv (scFv) proteins fused to the human IgG1 Fc domain (scFvIg). A novel bispecific scFvIg was constructed by cloning the two monospecific scFv binding sites in tandem, with the 9.6 scFv placed N-terminal to the 9-1 scFvIg. Monospecific scFvIg binding to CD2 was comparable to that of the corresponding parental mAb, while the bispecific scFvIg exhibited binding activity similar to that of the 9-1 scFvIg. The combination of 9.6 scFvIg and 9-1 mAb was mitogenic, whereas mixtures including the 9-1 scFvIg were non-stimulatory, confirming the unique properties of the 9-1 IgG3 Fc. Without the IgG3 tail, the bispecific 9.6/9-1 scFvIg was directly mitogenic and was a more potent mitogen than the mAb mixture, but was accessory cell dependent. Unlike the combination of mAb, the bispecific reagent did not directly mobilize calcium in T cells. In comparison to the mAb mixture, bispecific 9.6/9- 1 scFvIg-mediated stimulation of a mixed lymphocyte reaction was significantly more resistant to inhibition of the CD28 co-stimulatory pathway by the inhibitor CTLA-4-Ig. These results show that expression of the 9.6 and 9-1 binding sites together on a bispecific scFvIg increased the mitogenic properties of the mAb and altered the degree of accessory cell signals required for T cell activation.      

Streptococcus mutans-like bacteria from human dental plaque in a Sri Lanka (Ceylon) population

Abstract – This paper reports on the presence of low numbers of Streptococcus mutans among the oral streptococci present in human dental plaque in a Sri Lanka (Ceylon) population, where the caries activity is low and a low sucrose intake is combined with the presence of heavy plaque deposits. Plaque samples of unknown age were collected from 10 individuals in a tea estate, and another 10 samples were collected from dental students 19 days following interruption of oral hygiene. Of 670 such strains of oral streptococci studied, none showed typical "frosted glass" colony morphology on Mitis Salivarius agar. However, when subjected to physiological tests 14 of them were classified as S. mutans.     

炎症在启动和维持心房颤动中的地位——对研究资料的系统回顾

近年的研究显示,炎症在启动、维持心房颤动(房颤)中起非常重要的作用.美国Issac等对1995～2007年间以英文发表的有关房颤与炎症关系方面的文章,以及药物,如他汀类、血管紧张素转化酶抑制剂(ACEI)及糖皮质激素在治疗房颤中的作用方面的文章进行了系统回顾(J Am Coll Cardiol,2007, 50:2021-2028).     

A prospective randomized trial of the surgical blood order equation for ordering red cells for total hip arthroplasty patients

BACKGROUND: The majority of crossmatched blood is for surgical patients, and most of it is never transfused. An alternative system for ordering red cell (RBC) units, called the surgical blood order equation (SBOE), which incorporates specific patient variables for surgical patients, has been developed. STUDY DESIGN AND METHODS: A prospective double-blind randomized trial compared the SBOE with the maximal surgical blood order schedule (MSBOS) system for ordering allogeneic RBC units in 60 patients undergoing total hip arthroplasty. Autologous RBCs were available for none of the patients. RESULTS: There were no differences in patient demographic, surgical, or laboratory variables at any time. The median number (range) of allogeneic RBC units ordered was 2 (2-3) for the MSBOS and 0 (0-3) for the SBOE (p<0.0001). The SBOE ordered the correct number of RBC units for 58 percent of patients, while the MSBOS did so for 7 percent (p<0.0001). The SBOE had a lower crossmatch-to-transfusion ratio than the MSBOS (0.83 vs. 4.12). Costs were also lower with the SBOE. CONCLUSION: Incorporation of patient factors in the use of the SBOE system resulted in increased efficiency of blood-ordering practices for total hip arthroplasty.     

Comparison of micro-CT and cone beam CT-based assessments for relative difference of grey level distribution in a human mandible

Objectives:

The purpose of this study was to examine the ability of CT to assess the relative difference of degree of bone mineralization (grey level) parameters in a human mandible.

Methods:

Ten mandibular sections from cadavers (81.5 ± 12.1 years) were scanned using micro-CT with 27.2 μm voxel size and cone beam CT (CBCT) with 200 μm, 300 μm, and 400 μm voxel sizes. In addition, 15 clinical CBCT images from young patients (mean age 18.9 ± 3.3 years) were identified. After segmentation of bone voxels, alveolar bone and basal cortical bone regions were digitally isolated. A histogram of grey level, which is equivalent to degree of bone mineralization, was obtained from each region of the CT images. Mean, standard deviation (SD), coefficient of variation (COV), fifth percentile low (Low₅) and high (High₅) of alveolar bone and basal cortical bone regions were obtained. Percentage differences of grey level parameters between alveolar and basal cortical bones were computed.

Results:

The alveolar bone region had significantly lower Mean, Low₅ and High₅ values but significantly higher SD and COV than the basal cortical bone region for all CT images (p < 0.05). All parameters were significantly lower for the old cadaver group than for the young patient group (p < 0.05).

Conclusions:

CBCT and micro-CT provide comparable results in the assessment of relative difference in grey level distribution between alveolar and basal cortical bone regions in the human mandible. The percentage difference relative to an internal reference (basal cortical bone) can be a reliable method when assessing the degree of bone mineralization using CBCT images for both cross-sectional and longitudinal comparisons.