Lymphocyte Responses to an Aqueous Extract from Cow Hair and Dander

The proliferative responsiveness to cow dander antigens of lymphocytes from 23 asthmatic patients with allergy to cow hair and dander, from 10 patients with allergic asthma to other antigens and from 31 non-atopic subjects was investigated. Lymphocytes from patients with allergic asthma due to cow epithelium antigens showed a statistically significant decreased responsiveness to an extract from cow dander, compared to that seen with lymphocytes from newborn infants, lymphocytes from normal controls and from asthmatic patients without allergy to cow. The response to the cow dander extract seemed to be an accessory cell dependent T lymphocyte response.     

Standardization for image characteristics in telemammography using genetic and nonlinear algorithms

As the soft copy reading and computer assisted diagnosis (CAD) in mammography become more and more important, the standardization of digital images becomes paramount. Telemammography and telemedicine requires the standardization for image characteristics, such as image resolution, bit-depth and intensity response. Soft copy reading and CAD in mammography are both dependent on the characteristics of the source of the digital data, either direct digital mammography or digitized screen-film mammography. An algorithm developed on images from one database may not perform well as on images from another database (with a different digitization). In this paper, we describe two methods based on a genetic algorithm and a nonlinear algorithm for standardization of digitized and digital mammography. The proposed standardization techniques are based on geometric and intensity transformations that are discovered using a set of calibration images. A set of transformation algorithm is used to search for the best standardization.     

Biolistic transformation of conidia of Botryotinia fuckeliana

Botryotinia fuckeliana, the causal agent of grey mould, was biolistically transformed to hygromycin B resistance using a plasmid (pOHT) containing a bacterial hygromycin phosphotransferase gene fused to regulatory sequences from Aspergillus nidulans. Multiple copies of the plasmid, precipitated onto tungsten particles, were delivered into the conidia by a helium-driven gene gun. Southern analysis showed that the plasmid was integrated into the fungal genome at one single locus. After five subsequent transfers on selective medium, all transformants were mitotically stable. When propagated on non-selective medium, four out of eight transformants retained their resistance to hygromycin B. Southern analysis of the fifth generation of transformants showed that no genetic rearrangements occurred during vegetative growth of stable transformants.     

Transformation of Neurospora crassa with the trp-1 gene and the effect of host strain upon the fate of the transforming DNA

Summary Neurospora trp-1 ⁺ transformants, obtained by transforming a trp-1 inl strain with plasmid DNA containing the wild type trp1 ⁺ gene, were characterized by genetic and Southern blot analyses. The transforming trp-1 gene integrated at or near the resident site in all of the trp-1 ⁺ transformants obtained with circular DNA or DNA cut within the trp-1 coding region. The frequency of homologous integration decreased substantially when the donor DNA was cleaved outside the trp-1 coding region. The transformants were very stable mitotically and, in general, also showed meiotic stability. Analysis of trp-1 ⁺ transformants obtained with another recipient strain, trp-1 ⁺ ga-2 aro-9 inl, showed that homologous integration of donor DNA occurred in only 20% of the transformants, whether circular or linear DNA was used. Thus, the host strain employed for transformation appears to be a major factor in determining the fate of transforming DNA. Southern blot analysis of transformants showed that integration of the transforming DNA at the homologous site occurred by double crossover or gene conversion events rather than by insertion of the entire plasmid DNA. Multiple and apparently non functional integration events were observed in some transformants.     

三取代型钛钨硅酸盐体内抑瘤效应的免疫机制探讨

目的:探讨三取代型钛钨硅酸盐(WT)体内抑瘤效应的免疫机制。方法:建立荷H22肝癌小鼠模型,WT连续灌胃10d,取出肿瘤称重测定抑瘤率。用MTT比色法测定荷H22肝癌小鼠淋巴细胞转化的活性及NK细胞的杀伤活性。通过形态学观察和流式细胞仪检测WT诱导BEL-7402细胞的凋亡。结果:WT可显著抑制荷瘤小鼠肿瘤生长(P<0.05),提高荷瘤小鼠淋巴细胞转化的活性及NK细胞的杀伤活性(P<0.05),并诱导肿瘤细胞发生凋亡。结论:WT的抑瘤作用与机体免疫功能的增强有关。     

引入关联维的表面肌电信号的特征提取

考虑到表面肌电信号的非平稳特性,本研究在传统特征提取的基础上,又引入了非线性动力学中的关联维,通过小波系数的标准差和关联维重新构造特征向量,将其送入自组织映射网络对拇指弯曲、食指弯曲和无名指弯曲三种手势动作进行分类识别。结果表明:引入关联维的特征提取方法其识别正确率明显优于传统的小波变换的方法。可见,关联维作为一种新的特征参数,为肌电信号的特征提取提供了新的思路。     

Antigens targeted to the Leishmania phagolysosome are processed for CD4+ T cell recognition

Processing of antigen for recognition by class II-restricted CD4⁺ T cells occurs within acidic compartments of the antigen-presenting cell. The exact nature of this compartment has yet to be precisely defined, however, but may vary depending upon the cell type studied and the antigen used. The acidic compartments of macrophages are also responsible for the degradation of ingested micro-organisms and play host to others which are adapted to an intracellular existance. To determine whether the phagolysosome (PL) formed in activated macrophages after ingestion of Leishmania parasites is also a site for entry of antigen into the class II presentation pathway, we have used the approach of genetic transformation. Hence, Leishmania were transfected with the genes for the protein antigens ovalbumin (OVA) and β-galactosidase (β-gal) and after infection were able to deliver these antigens specifically into the PL. Delivery of antigen to this site resulted in the ability of infected macrophages to present these antigens to antigen-specific CD4⁺ T cells. After taking into account the absolute levels of antigen uptake by macrophages, a 4-h processing period for OVA delivered by this or a soluble route led to equivalent levels of T cell activation. Unlike macrophages pulsed with soluble OVA, those with PL-targeted OVA still retained the ability to stimulate T cells after a 24-h processing period. This enhanced lifespan of antigen in macrophages corresponded to the kinetics of degradation of the parasite, suggesting slow release of antigen into the processing pathway. β-gal presentation from the PL was tenfold less efficient under the same conditions. In addition to providing the first information on antigen processing in a protozoan PL, these studies highlight the usefulness of genetically transformed parasites for these types of studies.     

Critical role for SV40 small-t antigen in human cell transformation

Defining the ability of simian virus 40 (SV40) to transform human cells has become of even greater importance with the increased understanding that this virus may play a role in some human malignancies. This report documents the requirement for viral small-t (ST) antigen in large-T (LT)-driven transformation of primary fibroblasts, a requirement that cannot be met by a well-known oncogene, c-Ha-ras (EJ-ras), which can cooperate with LT in rodent systems. The cellular gene telomerase is not essential for transformation, although transformed clones are not immortal without it. Similarly, an immortal mesothelial cell line has been developed using LT and telomerase. Immortalized mesothelial cells are morphologically normal, but can be transformed by introduction of ST, or ST + ras, but not by ras alone. It is likely that ST will be required along with LT for transformation of most human cell types.     

Effect of α1-protease inhibitor (α1-antitrypsin on the intensity of transformation of phytohemagglutinin-stimulated lymphocytes

₁-Antitrypsin (₁-AT) reduces the intensity of transformation of human peripheral blood lymphocytes stimulated by phytohemagglutinin. The degree of inhibition is determined by the antiprotease activity of the ₁-AT. Maximal inhibition of transformation was shown to be 50%. Participation of ₁-AT in the control of activity of lymphoid tissue cells is postulated.Laboratory of Immunogenetics, Research Institute of Transplantology and Artificial Organs, Ministry of Health of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Orekhovich.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 1, pp. 35–36, January, 1980.     

Biolistic transformation of Trichoderma harzianum and Gliocladium virens using plasmid and genomic DNA

Biolistic (biological ballistic) and protoplast-mediated procedures were compared as methods for transforming strains of Gliocladium virens and Trichoderma harzianum. For biolistic transformation, conidia were bombarded using a helium-driven biolistic device to accelerate M5 tungsten particles coated with plasmid or genomic DNA. DNA from either source contained a bacterial hygromycin B resistance gene (hygB) as a dominant selectable marker. The same sources of DNA were also used to transform protoplasts using a standard polyethylene glycol-CaCl₂ protoplast fusion protocol. Hygromycin B-resistant (HygB^R) transformants were recovered from all strains, methods, and DNA sources except for genomic DNA used with the protoplast method. The biolistic procedure was technically simpler, and increased transformation frequency and genetic stability in the progeny as compared with the protoplast-mediated transformation. Southern analysis of homokaryotic HygB^R progenies showed that the transforming sequences were integrated into the genome of the recipient strains, and apparently were methylated. This is the first study presenting detailed results on biolistic transformation of a filamentous fungus.