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排序方式: 共有4193条查询结果,搜索用时 15 毫秒
21.
We provide microscopic evidence that motile rod-shaped forms of Ramlibacter tataouinensis TTB310 are formed from dividing cyst-like cells. Careful estimation of the size of the two morphotypes was conducted using optical and transmission electron microscopy (TEM). The cyst-like cell was shown to be a sphere with a diameter Dc=850 nm. The rod-shaped form was a round-ended cylinder with length Lr=2.91 microm and diameter Dr=239 nm. The membrane area of the two morphotypes was the same. However, the formation of rods from cysts involved loss of two-thirds of the cell volume. TEM showed that, prior to division and transition into rods, cysts contained condensed cytoplasmic material. These results suggest that the morphological transition occurs by pure reshaping of cells. 相似文献
22.
Thi Thu Ha Hoang Carina Bengtsson Dac Cam Phung Mikael Srberg Marta Granstrm 《Clinical and Vaccine Immunology : CVI》2005,12(1):81-85
Helicobacter pylori-associated diseases, such as peptic ulcer and gastric cancer, are common in Vietnam, but the prevalence of the infection is largely unknown. A validated enzyme-linked immunosorbent assay was used for seroepidemiology with 971 samples from the general population, ages 0 to 88 years, with 546 samples from an urban population (Hanoi), and with 425 samples from a poor, rural province (Hatay). The overall seroprevalence of the infection was 746 per 1,000, with a prevalence of 788 per 1,000 in Hanoi and 692 per 1,000 in Hatay (P = 0.0007). The risk for infection in the rural area of Hatay was 40% lower than in the urban population of Hanoi, with the odds ratio being 0.59 (95% confidence interval, 0.43 to 0.81). The study shows that the prevalence of H. pylori infection is high in Vietnam and especially high in a large urban area, such as the city of Hanoi. 相似文献
23.
J. Tamarelle A.C.M. Thiébaut B. de Barbeyrac C. Bébéar J. Ravel E. Delarocque-Astagneau 《Clinical microbiology and infection》2019,25(1):35-47
Background
The vaginal microbiota may modulate susceptibility to human papillomavirus (HPV), Chlamydia trachomatis, Neisseria gonorrhoeae and Mycoplasma genitalium infections. Persistent infection with a carcinogenic HPV is a prerequisite for cervical cancer, and C. trachomatis, N. gonorrheae and M. genitalium genital infections are all associated with pelvic inflammatory disease and subsequent infertility issues.Objectives
To evaluate the association between these infections and the vaginal microbiota.Data sources
The search was conducted on Medline and the Web of Science for articles published between 2000 and 2016.Study eligibility criteria
Inclusion criteria included a measure of association for vaginal microbiota and one of the considered STIs, female population, cohort, cross-sectional and interventional designs, and the use of PCR methods for pathogen detection.Methods
The vaginal microbiota was dichotomized into high-Lactobacillus vaginal microbiota (HL-VMB) and low-Lactobacillus vaginal microbiota (LL-VMB), using either Nugent score, Amsel's criteria, presence of clue cells or gene sequencing. A random effects model assuming heterogeneity among the studies was used for each STI considered.Results
The search yielded 1054 articles, of which 39 met the inclusion criteria. Measures of association with LL-VMB ranged from 0.6 (95% CI 0.3–1.2) to 2.8 (95% CI 0.3–28.0), 0.7 (95% CI 0.4–1.2) to 5.2 (95% CI 1.9–14.8), 0.8 (95% CI 0.5–1.4) to 3.8 (95% CI 0.4–36.2) and 0.4 (95% CI 0.1–1.5) to 6.1 (95% CI 2.0–18.5) for HPV, C. trachomatis, N. gonorrhoeae and M. genitalium infections, respectively.Conclusions
Although no clear trend for N. gonorrhoeae and M. genitalium infections could be detected, our results support a protective role of HL-VMB for HPV and C. trachomatis. Overall, these findings advocate for the use of high-resolution characterization methods for the vaginal microbiota and the need for longitudinal studies to lay the foundation for its integration in prevention and treatment strategies. 相似文献24.
Linda Wittkop Daniel Commenges Isabelle Pellegrin Dominique Breilh Didier Neau Denis Lacoste Jean-Luc Pellegrin Geneviève Chêne François Dabis Rodolphe Thiébaut 《BMC medical research methodology》2008,8(1):68
Background
Principal component analysis (PCA) and partial least square (PLS) regression may be useful to summarize the HIV genotypic information. Without pre-selection each mutation presented in at least one patient is considered with a different weight. We compared these two strategies with the construction of a usual genotypic score. 相似文献25.
Chronic diarrhea,hemorrhagic colitis,and hemolytic-uremic syndrome associated with HEp-2 adherent Escherichia coli in adults infected with human immunodeficiency virus in Bangui,Central African Republic
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Mossoro C Glaziou P Yassibanda S Lan NT Bekondi C Minssart P Bernier C Le Bouguénec C Germani Y 《Journal of clinical microbiology》2002,40(8):3086-3088
In human immunodeficiency virus (HIV)-infected adults from the Central African Republic, the occurrence of chronic diarrhea due to HEp-2 adherent Escherichia coli (EAEC) harboring virulence markers (eaeA, BFP, EAF, astA determinant of EAST/1, positive FAS test, enteropathogenic E. coli O serogroup) was shown to be associated with AIDS. We also show that EAEC that produce verotoxin (Stx2) but do not harbor the genetic markers for classical enterohemorrhagic E. coli are involved in hemorrhagic colitis and hemolytic-uremic syndrome in patients with HIV. 相似文献
26.
Astrid LA. Kuijpers Rolph Pfundt Patrick LJM Zeeuwen Henri OF. Molhuizen Edwin CM. Mariman Peter CM. van de Kerkhof Joost Schalkwijk 《Clinical genetics》1998,54(1):96-101
Psoriasis is a multifactorial skin disease characterised by epidermal abnormalities and infiltration by lymphocytes and polymorphonuclear leukocytes (PMN). Skin-derived antileukoproteinase (SKALP), also known as elafin, is a potent inhibitor of human leukocyte elastase and proteinase 3, two PMN-derived proteinases implicated in tissue destruction and leukocyte migration. We have shown that, at least at the protein level, SKALP is significantly decreased in lesional skin of patients with pustular psoriasis compared with plaque-type psoriasis. This finding raised the possibility that SKALP could be one of the candidate genes for pustular forms of psoriasis. We therefore performed single strand conformation polymorphism (SSCP) analysis on the SKALP gene to screen for mutations/polymorphisms in the exons of 30 patients with plaque-type psoriasis, 15 patients with pustular psoriasis and 48 healthy controls. In exon 1 a polymorphism was detected at position + 43 relative to the translation start site, resulting in a substitution of threonine for alanine in the signal peptide. In the promoter region a dinucleotide repeat polymorphism was identified. Both polymorphisms were not associated with pustular psoriasis, or psoriasis in general. Our data indicate that the decrease in SKALP activity in pustular psoriasis is not caused by mutations in the coding region of the gene, and that there is no allelic association between pustular psoriasis and SKALP gene polymorphisms. 相似文献
27.
The functional of B-L (Ia-equivalent)-positive (B-L+) adn -negative (B-L-) chicken peripheral blood lymphocytes (PBL) was studied in vitro and in vivo. The PBL were first stained in direct immunofluorescence tests with a fluorescein isothiocyanate-labelled anti-B-L alloantiserum and then separated by means of a fluorescence-activated cell sorter. In agreement with our previous findings, B-L- cells showed functional properties of T lymphocytes, responding to concanavalin A and phytohaemagglutinin-P in vitro and inducing a graft-versus-host (GVH) reaction when injected into allogeneic embryos. Sorted B-L+ gave no responses in any of these assays. Neither B-L+ nor B-L- cells, when tested alone, responded significantly to pokeweed mitogen, but mixtures of the two restored the responsiveness to that of the original unsorted suspension. Of the B-L+ PBL, 10% were T cells, which may account for the low GVH reactivity given by this population. 相似文献
28.
bcl-2 transgene expression promotes survival and reduces proliferation of CD3-CD4-CD8- T cell progenitors 总被引:16,自引:0,他引:16
Proliferative expansion and apoptotic cell death play prominent roles in T
cell development. The molecular control of cell cycle progression and
apoptosis appear to be inter-connected since the Bcl-2 protein can inhibit
apoptosis and slow cell cycle progression in cortical thymocytes and mature
T cells, particularly during the transition from the quiescent state into
the cell cycle. Here the impact of bcl-2 transgene expression on
CD3-CD4-CD8- T cell progenitors was assessed. Bcl-2 enhanced the survival
of these progenitors at all of the four major differentiation stages, CD25-
CD44+ (pro-T1), CD25 + CD44+ (pro- T2), CD25 + CD44- (pro-T3) and
CD25-CD44- (pro-T4). However, it reduced cell cycling and slowed turnover
only in the pro-T4 subset. From an analysis of bcl-2 transgenic mice
expressing a TCR transgene or bearing a mutation in the scid or rag-1 gene
we conclude that Bcl-2 inhibits proliferation only of T cell progenitors
that are activated via the pre- TCR, not those stimulated via c-Kit and the
IL-7 receptor.
相似文献
29.
30.
JUAN C. DE LA TORRE MARGARET MALLORY MICHELLE BROT LISA GOLD GEORGE KOOB MICHAEL B. A. OLDSTONE ELIEZER MASLIAH 《Virology》1996,220(2):508
Neurons have a restricted expression of MHC heavy chain molecules which prevents presentation of antigens of infecting viruses. As a result, such infected cells escape immune surveillance and allow the establishment of noncytolytic persistent infection. Here we show that a chronic noncytolytic viral infection bothin vitroandin vivoselectively perturbed the expression of GAP-43, a protein that plays a central role in neuronal plasticity processes accompanying learning and memory. GAP-43 expression was greatly decreased in the hippocampus, an area of heightened viral replication, while synaptic density was preserved. Concurrently, the ability to learn tasks was significantly impaired in these persistently infected mice. Yet, infected neurons remained free from structural injury. 相似文献