用神经网络法预测药物在体透过人皮肤的渗透性

目的：预测药物在体透过人皮肤的渗透性。方法：以正辛醇／水分配系数(logP)、分子体积(V)、氢键酸度(∑β2^H)和氢键碱度(∑β2^H)等理化参数作为输入层神经元，以药物在一定时间内在体透过人皮肤的透过比的对数值(R，透过量／未透过量)作为输出层神经元，建立起合适的BP(Back—propagation)神经网络。结果：17个药物在一定时间内在体透过人皮肤的透过比的神经网络计算值和实测值均相当符合。结论：用BP神经网络法可以较好地预测药物在体透过人皮肤的渗透性。     

抑制素(Inhibin)的研究 Ⅰ.人精液抑制素的制备及其生物学特性

本文报道人精液抑制素的制备及其生物学特性。收集的新鲜人精液经乙醇沉淀和丙酮冲洗,获得的粗提物经Sephadex G100处理,产生具有高活性抑制素hP2组分。应用hP2测定使去势雄性大鼠增高的血清FSH水平降低。其生物特性:hP2的生物活性按单位重量计算为粗提物的10倍以上,包含16种氨基酸,通过SDS-PAGE计算分子量为11,500道尔顿。     

荧光探针标记单克隆抗体在不同条件下的荧光变化

应用流式细胞术，探讨了不同贮存条件和时间对ＦＩＴＣ和ＰＥ标记单抗的荧光变化。结果表明４℃－３０℃１冷冻干燥对ＦＩＴＣ标主单抗无明显影响，ＰＥ偶联物皮４℃为宜。两种标记物检测的正常粉外周血Ｔ细胞及其亚群结果一致。     

分子标记在医学蠕虫遗传多态性研究中的应用

医学蠕虫引起的人兽共患寄生虫病严重危害人类健康。对医学蠕虫进行遗传多态性研究,不仅可以了解其种群的生物学特性和遗传结构,而且有助于揭示它们如何适应寄生环境,从而有助于对寄生虫病流行规律的认识,加深对寄生虫病精准防控的理解。随着分子生物学的发展,DNA条形码、简单序列重复、单核苷酸多态性标记等分子标记已被广泛应用于研究寄生虫个体间及群体间的遗传关系,揭示寄生虫种群的遗传变异、物种的起源进化等。本文对目前常用的三类分子标记在医学蠕虫遗传多态性研究中的应用进行系统综述,以期为相关研究奠定基础。     

Probe tine diameter and probing depth

The aim of this study was to assess the effect of difference in tine diameter on probing pocket depth measurement. 2 sets of tines with Williams markings at 1, 2, 3, 5, 7, 8, 9 and 10 mm, and with a "round" tip, diameter 0.5 mm, were compared. One set was described as parallel-sided, the other as tapered. The parallel-sided tine was almost parallel from the 10 mm marking to the tip (tip diameter mean = 0.46 mm, 95% C.I. 0.456-0.464), while the corresponding diameter for the tapered tine varied (tip diameter mean = 0.48 mm, 95% C.I. 0.473-0.489). Calibration markings appeared highly consistent with the expected value to within 0.01 mm. The tines were mounted in Brodontic handles at 0.25 N. Examiner probing repeatability yielded kappa 0.86 for "parallel-sided" and 0.81 for "tapered" tines in vivo. 412 approximal pockets were assessed in 53 patients with routine chronic adult periodontitis, mean age 42.1 years. Each site had a probing depth of greater than or equal to 5 mm, PlI less than or equal to 1, GI less than or equal to 1, PBI less than or equal to 1. Each site was probed 2x with a 15-min interval. At the first 251 sites, the parallel-sided tine was used initially, and the tapered at the remaining 161 sites. Results indicated a highly significant tendency for the parallel-sided tine to yield a deeper reading when a difference occurred. These findings indicate that with adequate training providing high examiner repeatability, one source of error in probing data can be minimised.     

"Reverse" DMA hybridization method for the rapid identification of subgingival microorganisms

A "reverse" hybridization method is described, in which whole chromosomal DNA was extracted from 10-20 colonies of "unknown" strains in pure culture and labelled with digoxigenin by a random primer technique. DNA probes were prepared from a total of 23 strains and hybridized with targets containing 100 ng purified, denatured DNA from 38 reference strains fixed to nitrocellulose. 21/23 digoxigenin-labelled DNA probes successfully detected all members of the homologous species present on filters. Probes to Fusobacterium nucleatum strains 364 and MG detected 3/4 and 1/4 members of this species, respectively; 13/23 probes were 100% specific, but cross reactions between 10 probes and DNA targets from closely related, heterologous species occurred in 15/834 possible instances. False-positive reactions that occurred between closely related species were, however, easily distinguished and did not prevent the accurate identification of probe strains. Digoxigenin-labelled probes were capable of detecting 100 pg of homologous DNA. The reverse hybridization procedure allows identification or grouping of a large number of isolates within 3 days and provides a more economical means of characterizing subgingival isolates than predominant cultivable techniques and conventional phenotypic testing. This method could be adapted for the direct identification of microorganisms in subgingival plaque samples.     

Currently used nucleic acid amplification tests for the detection of viruses and atypicals in acute respiratory infections

For the detection of respiratory viruses conventional culture techniques are still considered as the gold standard. However, results are mostly available too late to have an impact on patient management. The latest developments include appropriate DNA- and RNA-based amplification techniques (both NASBA and PCR) for the detection of an extended number of agents responsible for LRTI. Real time amplification, the latest technical progress, produces, within a considerable shorter time, results with a lower risk of false positives. As results can be obtained within the same day, patient management with appropriate therapy or reduction of unnecessary antibiotic therapy in LRTI will be possible. A number of technical aspects of these amplification assays, and their advantages are discussed.The availability and use of these new diagnostic tools in virology has contributed to a better understanding of the role of respiratory viruses in LRTI. The increasing importance of the viral agents, Mycoplasma pneumoniae and Chlamydophila pneumoniae in ARI is illustrated. A great proportion of ARI are caused by viruses, but their relative importance depends on the spectrum of agents covered by the diagnostic techniques and on the populations studied, the geographical location and the season. The discovery of new viruses is ongoing; examples are the hMPV and the increasing number of coronaviruses. Indications for the use of these rapid techniques in different clinical situations are discussed. Depending on the possibilities, the laboratory could optimize its diagnostic strategy by applying a combination of immunofluorescence for the detection of RSV an IFL, and a combination of real-time amplification tests for other respiratory viruses and the atypical agents. When implementing a strategy, a compromise between sensitivity, clinical utility, turn around time and cost will have to be found.     

Hepatitis C virus (HCV) genotype 1 NS5A resistance-associated variants are associated with advanced liver fibrosis independently of HCV-transmission clusters

Objectives

The aim of the study was to characterize the differences in the frequencies of NS3 and NS5A resistance-associated variants (RAVs) among Polish therapy-naive genotype 1 (G1) hepatitis C virus (HCV)-monoinfected and human immunodeficiency virus (HIV)/HCV-coinfected patients including clustering patterns and association of RAV frequency with liver fibrosis.

Significance of methods for purification of oligodeoxyribonucleotide probes for the efficiency of gene diagnosis by real-time PCR

Analysis of the use of real-time PCR with fluorescent registration of results for gene diagnosis of infectious diseases showed that the sensitivity and reliability of quantitative evaluation of DNA targets directly depended on the method of purification of oligonucleotide probes. Chromatographic behavior of synthetic probes carrying various fluorophores and fluorescence quenchers was analyzed. Approaches to optimization of purification methods are proposed enabling elimination of previously undetectable admixtures. The importance of these studies is explained by the need in extending the armory of methods for the development and production of diagnosticums for detection of infectious and hereditary diseases, identification of genetically modified organisms, and for a wide spectrum of research in molecular biology and medicine. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 3, pp. 280–284, March, 2008     

The use of DIG-labelled cRNA probes for the detection of cymbidium mosaic potexvirus (CymMV) and odontoglossum ringspot tobamovirus (ORSV) in orchids

DIG-labelled sense and antisense cRNA probes were synthesized from cDNA clones of CymMV and ORSV for virus detection in infected plants. A slot-blot hybridization assay was developed using either crude leaf extracts or total RNA from infected leaves. The assay could detect 50 and 250 pg of purified CymMV and ORSV RNA, respectively. As little as 30 mg of Nicotiana benthamiana infected leaves was sufficient to provide positive detection. CymMV and ORSV were detected at 3125 and 625 times dilution of leaf extracts, respectively. The DIG-labelled cRNA probes are stable for more than a year. This method is sensitive, reliable and suitable for large-scale routine testing of plant viruses. By using the two DIG-labelled cRNA probes in situ, CymMV and ORSV were localized in systemically infected leaves and stems of N. benthamiana and orchids.