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1.
2.
DNA restriction-site polymorphisms associated with the alpha 1-antitrypsin gene. 总被引:9,自引:4,他引:5
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Restriction-site variation in and around the alpha 1-antitrypsin gene has been studied using two genomic probes. With use of restriction enzymes SstI, MspI, and AvaII, three polymorphic sites have been described with a 4.6-kb probe in the 5' portion of the gene. With use of a 6.5-kb probe, polymorphisms in the coding and 3' regions of the gene have been detected with AvaII, MaeIII, and TaqI. All of these polymorphisms are of sufficiently high frequency to be useful in genetic mapping studies. The polymorphisms with AvaII and MaeIII (6.5-kb probe) are particularly useful for prenatal diagnosis. PI types and M subtypes tend to be associated with specific DNA haplotypes; there are two different types of DNA haplotypes associated with PI M1. The extent of linkage disequilibrium differs throughout the region of the alpha 1-antitrypsin gene. 相似文献
3.
To complement the role of primary care teams working with patients with HIV disease and AIDS within greater London and to ease the load on the special hospital units a home support team was developed. It comprises six specialist nurses, a general practitioner trained medical officer, and a receptionist and is funded from regional and district sources and charities. A nurse is available for out of hours and emergency weekend calls, with support from the patient''s general practitioner or the attached medical officer. During the first 18 months 249 patients were seen; the mean duration of care was five months. Nearly a third (18/50, 30%) of patients who were terminally ill died at home. The team''s activities included practical nursing care, emotional support for carers and patients, and advice and guidance to primary care teams. Problems in providing care in patients'' homes included issues relating to confidentiality and 24 hour cover. With the increasing incidence of HIV infection the home support team may be a useful model for care of large numbers of patients with symptomatic HIV disease, especially in large urban areas. 相似文献
4.
E E Grebner D A Mansfield S S Raghavan E H Kolodny A d'Azzo E F Neufeld L G Jackson 《American journal of human genetics》1986,38(4):505-514
Two abnormalities of beta-hexosaminidase A (HEX A) activity are described. One, found in two unrelated Jewish children, was characterized by the complete absence of HEX A activity in serum, but low levels of activity in leukocytes and fibroblasts using artificial substrate. The other, found in a non-Jewish man, was characterized by uniformly low levels of HEX A activity in leukocytes, fibroblasts, and serum against artificial substrate. In all cases, the pH optimum of HEX A was normal, there was no increased lability at 37 degrees C, and no inhibitor was detected to account for the deficiency of activity. Cultured fibroblasts of these individuals were capable of synthesizing and processing alpha- and beta-subunits of HEX A and capable of cleaving GM2 ganglioside. The patients, ranging in age from 6 to 30 years, are clinically normal. They are probably genetic compounds carrying the classical Tay-Sachs gene and a differently mutated allele that imparts the anomalous phenotypic features observed. 相似文献
5.
Optical measurements were made during low temperature photoreduction of photosystem I acceptors, A1 and A0. In the presence of a significant amount ofA1 (detected by EPR), no absorbance changes occurred between 750-350 nm, indicating that this species is not a chlorophyll or pheophytin molecule. Spectral changes in this region that may be correlated with the appearance of A−0, suggest that this component is a chlorophyll a anion monomer. The species is present in reaction centres in a ratio of 0.94 Ao/P700.
Photosystem I Primary acceptor Optical difference spectrum Chlorophyll a monomer 相似文献
6.
Lymphocyte function in experimental African trypanosomiasis. VII. Loss of antigen-nonspecific suppressor-T-cell activity 总被引:1,自引:0,他引:1
The extent of immunosuppression occurring in mice infected with the pathogenic African trypanosomes was studied. Spleen cells from Trypanosoma rhodesiense-infected C57BL/6J mice were tested for antigen-nonspecific suppressor-T-cell (Ts) activity after concanavalin A (Con A) treatment in vitro. After exposure to Con A, control and infected mouse spleen cells were added to responder spleen cell cultures stimulated with sheep erythrocytes (SRBC). Assays for the resultant plaque-forming cell responses to SRBC revealed that antigen-nonspecific Ts activity was lost during the first week of infection. Changes in infected mouse T-cell subpopulations, including a terminal loss of Lyt 2.2+ cells, accompanied but did not precede the demonstrable loss of Ts function. Splenic suppressor macrophages which arise during infections with T. rhodesiense also did not seem to be associated with the loss of antigen-nonspecific Ts activity. It is concluded that the generalized immunosuppression associated with experimental African trypanosomiasis extends to the mitogen-induced Ts population. 相似文献
7.
Patricia A. McLenachan Peter J. Lockhart H. Rick Faber Brian C. Mansfield 《Journal of molecular evolution》1996,42(2):273-280
The pregnancy-specific 1-glycoproteins (PSG) form a large family of closely related proteins. Using newly developed methods of sequence analysis, in combination with protein modeling, we provide a framework for investigating the evolution and biological function of genes like the PSG. Evolutionary trees, based on C-terminal sequence, group PSG genes in a manner consistent with their genomic organization. Trees constructed using the N-terminal domain sequences are unreliable as an indicator of phylogeny because of non-neutral processes of sequence change. During duplication of the PSG genes, evolutionary pressures have resulted in a gradient of constrained change across each gene. The N-terminal domains show a nonrandom pattern of amino acid substitutions clustered in the immunoglobulin complementarity-determining region (CDR)-like regions, which appear to be important in the function of the protein. 相似文献
8.
L.P. Mansfield E. Billett E. Olsen S.J. Forsythe 《Letters in applied microbiology》1996,23(2):104-106
L.P. MANSFIELD, E. BILLETT, E. OLSEN AND S.J. FORSYTHE. 1996. The lipopolysaccharide antigenicity of 22 Salmonella strains (representing nine serogroups) and four non-salmonellae Enterobacteriaceae to the Salmonella genus specific monoclonal antibody M105 was analysed. The monoclonal antibody M105 reacted with all 22 Salmonella strains. Probing SDS-PAGE separated LPS molecules with MAb M105 revealed that the antibody reacted with the core region of all Salmonella serovars. However, no reaction was obtained to the long-chain LPS of serovars O ( Salm. adelaide and Salm. ealing ), C1 ( Salm. infantis, Salm. livingstone and Salm. virchow ) or Salm. arizonae . It is plausible that the presence of a second core antigenic type results in the lack of reaction between long-chain LPS and the Salmonella genus specific monoclonal antibody M105. 相似文献
9.
S. D. Mansfield K. K. Y. Wong E. de Jong J. N. Saddler 《Applied microbiology and biotechnology》1996,46(4):319-326
A commercial xylanase from Trichoderma longibrachiatum was used to treat the fractions of Douglas-fir kraft pulp of different fibre length. Enzymatic prebleaching was followed by chelation and peroxide bleaching. An evaluation of both optical and physical properties of the distinct fractions was conducted. A difference in susceptibility of the fractions of different fibre length to xylanase prebleaching was observed. The bleach-boosting effect observed with all fractions appeared to be related to the high-molecular-mass UV-absorbing material solubilized during enzyme treatments. Xylanase treatments resulted in beneficial effects to handsheet density and roughness as well as to some of the strength properties. However, the response to the xylanase treatments exhibited by all fractions of different fibre length was not uniform, indicating that fiber composition played a key role in the effectiveness of xylanase treatments. 相似文献
10.
Immunomagnetic separation as an alternative to enrichment broths for Salmonella detection 总被引:7,自引:1,他引:6
One hundred and twenty foodstuffs were tested for the enrichment of Salmonella species by immunoseparation. The foodstuffs covered six groups: raw chicken, prawns, skimmed milk powder, herbs and spices, cocoa powder and animal feed. Half of the food samples were spiked with one Salmonella species: Salm. ealing, Salm. enteritidis, Salm. give, Salm. typhimurium or Salm. virchow . Comparison of Salmonella recovery with standard methods (selenite cystine broth, tetrathionate broth and Rappaport-Vassiliadis broth) was carried out. Immunoseparation gave similar numbers of true positives to the standard enrichment methods in a short time period. Only immunoseparation isolated Salmonella species from spiked garlic granules demonstrating the possible recovery of sublethally injured cells. 相似文献