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81.
We report the capacity of CD40 ligand (CD40L)-negative T cell clones to activate human B cells. CD40L-negative T cells induce a level of B cell proliferation 10–20% of that seen with normal T cells. The signal provided by the negative clones is synergistic with that derived from a CD40L transfectant, and restores B cell proliferation to normal levels, showing that CD40L-negative T cell clones are not inherently inhibitory for B cells. Although their capacity to induce proliferation was much reduced, CD40L-negative T cell clones were still strong inducers of B cell differentiation to plasma cells. This differentiation to plasma cells was inhibited by a CD40L transfectant. The data are discussed with regard to the normal in vivo mechanism for maintaining B cell memory and memory antibody responses to T-dependent antigens.  相似文献   
82.
Summary The present study was designed to investigate the relationships between premenstrual symptomatology, locus of control, anxiety, and depression in women with normal menstrual cycles. Sixty-nine female participants completed a survey, comprised of the Menstrual Distress Questionnaire (MDQ; Moos, 1968), Levenson's (1981) locus of control scales, the Depression Anxiety Stress Scale (DASS; Lovibond and Lovibond, 1995), and a questionnaire constructed by the researchers based on the DSM-IV criteria for Premenstrual Dysphoric Disorder (PMDD). Both overall and specific subtypes of premenstrual symptomatology were found to correlate with external locus of control, anxiety, and depression. In addition, locus of control was found to moderate the relationship between premenstrual symptomatology, anxiety and depression. Finally, women who were in the premenstrual phase when completing the questionnaire scored significantly lower on the internal scale than those in either the follicular or early luteal phases. It was concluded that an external locus of control may be associated with a susceptibility to depression or anxiety when certain premenstrual or postmenstrual changes are experienced. Received August 10, 2002; accepted January 12, 2003 Published online February 19, 2003 Abbreviations · ANOVA · Analysis of variance · DASS · Depression anxiety stress scale · LOC · Locus of control · MANOVA · Multivariate analysis of variance · MDQ · Menstrual distress questionnaire · PMDD · Premenstrual dysphoric disorder · PMS · Premenstrual syndrome Acknowledgement The authors would like to thank John Reece, Department of Psychology and Disability Studies, RMIT University, Melbourne, Australia, for assistance with data analysis. Correspondence: Dr. Andrew Francis, Department of Psychology and Disability Studies, Faculty of Applied Science, RMIT University, P.O. Box 71, Bundoora, Victoria 3083, Australia; e-mail: andrew.francis@rmit.edu.au  相似文献   
83.
Decreases in the detection of CD127 expression on T cells of human immunodeficiency virus-infected patients by flow cytometry can occur by delayed processing or by peripheral blood mononuclear cell isolation and cryopreservation. These observations should be considered in the interpretation of functional studies and the planning of multicenter clinical trials.  相似文献   
84.
Testing computer-controlled linear accelerators for patient safety and proper patient dose delivery requires that certain beam characteristics be monitored over an extended period of time. Computer-controlled conformal radiation therapy using asymmetric collimator jaw settings necessitates stable symmetric treatment beams. Long term beam symmetry measurements have been performed on a Philips SL20 dual energy computer-controlled linear accelerator. Symmetry in both the radial and transverse axis of each x-ray beam was monitored for eight gantry positions. These measurements were undertaken to determine the effectiveness of the SL20 beam steering system during dose delivery of 50 monitor units (MU) per field. Evaluation of the data shows that careful beam steering setup procedures result in x-ray beams in which fluctuations in symmetry as a function of gantry angle are within +/- 1.5%. Day to day instabilities produce a total overall variation in beam symmetry on the order of +/- 2.0%. Results suggest the measurement of symmetry as a function of gantry position become a routine quality assurance procedure for this accelerator.  相似文献   
85.
Two (ATT) trinucleotide repeat polymorphisms have been identified in the tails of Alu repeat elements in intron 5 of the antithrombin gene. The frequency and distribution of allele sizes for the Alu 5 and Alu 8 tail polymorphisms have been defined in a sample Caucasian population. The Alu 5 polymorphism has two alleles while that of Alu 8 has 10 alleles with a heterozygosity of 0.83. These polymorphisms have been used in combination with four previously described polymorphisms within the antithrombin gene to construct antithrombin gene haplotypes in the sample Caucasian population. Twenty-two different haplotypes were observed, with the Alu 8 polymorphism being particularly useful in subdividing the core haplotype based on the previously identified polymorphisms. The haplotype data were used to investigate the origin of repeat mutations within the antithrombin locus. We compared the haplotypes associated the mutant antithrombin genes in five families with the mutation 2759C→T (L99F) and five families with the mutation 5381C→T (R129Stop). The mutation 2759C→T (L99F), which occurs within a non-CpG dinucleotide, was carried on a gene associated with an identical haplotype in each of the five families. The mutation 5381C→T (R129Stop), a single base substitution within a CpG dinucleotide, was associated with at least two different haplotypes. The findings suggest a founder effect in the five families sharing the 2759C→T (L99F) and at least two independent origins for the CpG dinucleotide mutation 5381C→T (Rl29Stop). © 1994 Wiley-Liss, Inc.  相似文献   
86.
Expression of p53 protein in infiltrating and in-situ breast carcinomas.   总被引:6,自引:0,他引:6  
Five antibodies directed against the whole or part of p53 protein have been used to detect the protein immunohistochemically in 70 infiltrating breast carcinomas and 10 ductal carcinomas in situ. Mutations are known to occur in different conserved domains, and the antibodies employed spanned the expected sites. p53 protein was identified in 53 per cent of infiltrating carcinomas using the antibodies PAb 240, PAb 1801, C19, and JG8. The antibody PAb 421 detected the protein in 31.5 per cent; all positive with the other antibodies. Well-differentiated oestrogen receptor-positive tumours had a low incidence of p53 detection. Variation in the percentage of reactivity was seen between carcinomas and in some cases between different antibodies in the same cancer. Those carcinomas with a high percentage of positive cells with all antibodies were more likely to have metastasized to nodes, be at an advanced stage, and be oestrogen receptor-negative/epidermal growth factor receptor-positive. There was no significant correlation with c-erbB-2 protein expression or retinoblastoma protein loss. p53 protein was detected in a high proportion of cells in three of the six comedo ductal carcinomas in situ studied but either not at all or at a lower level in tumours of the cribriform type. p53 mutations are common in breast carcinomas, but heterogeneity within individual tumours is frequent. Marked expression of p53 appears to relate to tumour progression.  相似文献   
87.
A total of 447 cervical or vaginal specimens were inoculated in parallel onto peptone-starch-dextrose (PSD) and Columbia colistin (10 mg/ml)-nalidixic acid (15 mug/ml) (CNA) agar and were incubated for 48 h at 35 degrees C in an atmosphere with 2 to 10% CO2. One hundred (22.4%) of the cultures were positive for Haemophilus vaginalis. Forty-eight of the isolates were recovered from both PSD and Columbia CNA agar, five from PSD only, and 47 from Columbia CNA agar only (P less than 0.001). On Columbia CNA agar, 76 of the isolates were detected after 24 h of incubation, and the remainder were detected within 4 days of incubation.  相似文献   
88.
Viral myocarditis is remarkably common, being detected in approximately 1% of unselected asymptomatic individuals. Many cases are attributable to enteroviral infection, and in particular to coxsackievirus B3. The underlying pathogenesis is controversial, but most studies admit the important immunopathological role of infiltrating CD8+ (cytotoxic) T lymphocytes (CTLs). We have previously shown that CTLs play conflicting roles in coxsackievirus B (CVB) myocarditis; they assist in controlling virus replication, but also are instrumental in causing the extensive inflammatory disease, which often results in severe myocardial scarring. A role for perforin, the major CTL cytolytic protein, in CVB myocarditis has been suggested, but never proven. In the present study we use perforin knockout (PKO) mice to show that perforin plays a major role in CVB infection; in broad terms, perforin is important in immunopathology, but not in CVB clearance. For example, PKO mice are better able to withstand a normally lethal dose of CVB (100% survival of PKO mice compared with 90% death in +/+ littermates). In addition, PKO mice given a nonlethal dose of CVB develop only a mild myocarditis, whereas their perforin+ littermates have extensive myocardial lesions. The myocarditis in PKO mice resolves more quickly, and these mice show minimal histological sequelae; in contrast, late in disease the perforin+ mice develop severe myocardial fibrosis. PKO mice, despite lacking this major CTL effector function, can control the infection and eradicate the virus; growth kinetics and peak CVB titers are indistinguishable in PKO and perforin+ mice. Therefore, the immunopathological and antiviral effects of CTLs can be uncoupled by ablation of perforin; this offers a promising target for therapy of myocarditis. Furthermore, we evaluate the possible roles of apoptosis, and of chemokine expression, in CVB infection. In perforin+ mice, apoptotic cells are detected within the inflammatory infiltrate, whereas in their PKO counterparts, apoptotic myocyte nuclei are seen. Chemokine expression in both PKO and perforin+ mice precedes and parallels the course of myocarditis. Several chemokines are detectable earlier in PKO mice than in perforin+ mice, but PKO mice show reduced peak levels, and chemokine expression decays sooner. In particular, MIP-1α expression is barely detectable at any time point in PKO mice, but it is readily identified in perforin+ animals, peaking just before the time of maximal myocarditis; this is particularly interesting, given that MIP-1α knockout mice are resistant to CVB myocarditis, but remain able to control viral infection. Thus, the chemokine pathway offers a second route of intervention to diminish myocarditis and its sequelae, while permitting the host to eradicate the virus.  相似文献   
89.
Isolates of Borrelia turicatae, Borrelia parkeri, and the Florida canine borrelia (FCB) were examined to further phylogenetically characterize the identities of these spirochetes in the United States. DNA sequences of four chromosomal loci (the 16S rRNA gene, flaB, gyrB, and glpQ) were determined for eight isolates of B. turicatae and six isolates of B. parkeri, which grouped the spirochetes into two distinct but closely related taxa (>98% sequence identity) separate from Borrelia hermsii. The FCB was clearly separated with the group identified as B. turicatae, confirming this bacterium as a relapsing fever spirochete. Therefore, the potential for tick-borne relapsing fever in humans and other animals exists in Florida and future efforts are needed to determine the enzootic hosts and distribution of this spirochete in the southeastern United States. Analysis of plasmids demonstrated both linear and circular forms in B. turicatae but only linear plasmids in B. parkeri, which should be of interest to investigators concerned with plasmid diversity and evolution within this group of spirochetes.  相似文献   
90.
We present data from a clinical trial study in which an automated version (Galileo) of a previously described Q-Beta replicase-amplified probe assay (J. S. Shah et al., J. Clin. Microbiol. 33:1435-1441, 1995) was used for the direct detection of Mycobacterium tuberculosis complex in sputum. The assay was designed to target specific regions of 23S rRNA found in M. tuberculosis, Mycobacterium bovis, Mycobacterium africanum, and Mycobacterium microti and had a sensitivity ranging from approximately <10 to 300 CFU. The assay was tested for cross-hybridization by using large numbers (e.g., 10(5)to 10(10) CFU/assay) of 133 other organisms commonly found in respiratory tract samples, including non-M. tuberculosis Mycobacterium spp., other bacteria, fungi, and viruses. All of these competitors tested negative by the assay. Automated assay results for 780 respiratory tract samples (sputum or bronchoalveolar lavage specimens) collected and tested at three trial sites in the United States) were compared with the results of culture and acid-fast microscopy. Aliquots of conventionally digested and decontaminated sputum pellets were heated at 100 degrees C and mechanically disrupted prior to hybridization and background reduction, amplification, and detection in a closed disposable test pack. Pertinent elements of individual patient histories relating to tuberculosis exposure, previous active disease, antituberculosis therapy status, etc., were considered in the resolution of discrepant results for 48 (assay false-positive) samples. Seventy-one of 90 (78.9%) culture-positive samples were positive when tested in the Galileo assay, while 7% of culture-negative samples were assay positive, corresponding to a sensitivity of 79% and a specificity of 93%. Following resolution of discrepant results by chart review, the sensitivity and specificity for the Q-Beta replicase amplification assay with the Galileo analyzer were 84 and 97%, respectively. A total of 69.2% of smear-negative (culture positive) samples were detected by the assay. Ten test packs at a time were automatically processed by the Galileo analyzer without operator intervention following loading of samples. The first result was reported in approximately 3 h, and the last result was available in 6.5 h. To our knowledge, this is the first report of a clinical study with a fully automated amplification probe hybridization assay for the detection of pathogens directly from a clinical specimen.  相似文献   
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