T-cell homing within germinal centres (GCs) is required for humoral B-cell responses. However, the mechanisms implicated in the recruitment of T cells into the GC are not completely understood. Here we show, by immunohistology, and Northern and Western blots, that in vivo human GC B lymphocytes can express CxC and CC chemokines. Moreover, B-cell subset-specific experiments reveal that interleukin (IL)-8 and regulated on activation, normal, T-cell expressed, and secreted (RANTES) are predominantly expressed by GC centroblast and centrocytes, suggesting that chemokine expression is essential at stages in which B-lymphocytes engage in active antigen-dependent interactions with T lymphocytes. In keeping with this hypothesis, we show that the T cells recruited into the GC correlatively express the receptors for IL-8 and RANTES. We propose that chemokine expression is a key B-cell function that facilitates T-lymphocyte recruitment into the GCs and supports cognate B-cell : T-cell encounters. Moreover, our data are consistent with the impaired homing of T cells to secondary lymphoid organs in mice that are either deficient in CC and CxC chemokines or their receptors. 相似文献
Oxygen radical generation is known to be detrimental to sperm function,
especially motility, through the lipid peroxidation of the membranes.
Generation of reactive oxygen species can be induced by leukocyte
contamination, sperm centrifugation and the presence of abnormal
spermatozoa with excess residual cytoplasm. This study aims to evaluate the
effect on sperm motility of incubation in an antioxidant-containing
solution, during liquefaction and centrifugation. Thirty semen samples were
each divided into two equal parts: one mixed with Tyrode's solution, the
other with a salt solution containing antioxidants (Sperm- Fit; Ellios
Bio-Media, Paris, France). All the procedures were identical in the two
groups. The ratio of leukocytes to spermatozoa was significantly correlated
with the motility after liquefaction and after a 24 h incubation in routine
in-vitro fertilization (IVF) medium and with the number of motile
spermatozoa recovered after Percoll preparation. Moreover, when this ratio
was > or = 0.2, all motility parameters were lowered. Incubation with
Sperm-Fit allowed a higher percentage of motility after Percoll preparation
when the ratio was > or = 0.2 (48 +/- 5% versus 41 +/- 6% for Sperm-Fit
and Tyrode's solution respectively; P < 0.05) and a greater number of
motile spermatozoa recovered after Percoll preparation, whatever the ratio
(3.2 +/- 1.0 x 10(6) versus 2.4 +/- 0.7 x 10(6) for Sperm-Fit and Tyrode's
solution respectively when ratio > or = 0.2; 18.1 +/- 3.4 x 10(6) versus
14.4 +/- 2.9 x 10(6) for Sperm-Fit and Tyrode's solution respectively when
ratio < 0.2; P < 0.05). These results show that incubation with
antioxidants during liquefaction and centrifugation increases recovery of
motile spermatozoa.
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Cross-reactions between bovine serum albumin and equine serum albumin were studied using heterologous soluble complexes and specifically purified cross-reacting antibody.
Experiments with soluble complexes showed that homologous antigen can displace heterologous antigen specifically bound to antibody but heterologous antigen cannot displace homologous antigen. On gel precipitation tests a specific precipitation resulted when heterologous soluble complex reacted with homologous antigen.
By using equine serum albumin conjugated to polyaminopolystyrene the cross-reacting antibodies from anti-bovine serum albumin imune sera could be isolated. These are divalent 7S, γ-globulin antibodies. A figure of cross-reaction was obtained when these purified antibodies were tested by double diffusion in agar with bovine and equine serum albumins.
The results obtained both with soluble complexes and with purified antibody support the view that cross-reacting antibody is more avid for the homologous than for the heterologous antigen.
Based on the dissection of 30 hemi-mandibles, the authors report a study of the inferior alveolar artery in its intraosseous course. On morphologic considerations they propose a classification of the collaterals into two groups: the principal collaterals destined for the teeth and the bony alveolar tissue and the secondary collaterals destined for the sheath and the nerve as well as the bony tissue around the canal. Loss of the teeth and absorption of the alveolar bone modify the caliber of the inferior alveolar arterial axis, the distribution of its collaterals and possibly its mode of termination. These facts suggest a consideration of the vascularization of the mandible in terms of four sectors. They arrive at practical conclusions that may be drawn from this study in stomatology. 相似文献
Arginase activity was measured in serum and biopsy from healthy individuals and colorectal cancer patients. Arginase activity
in tumor samples (87±7.7 U/g tissue) was significantly higher than in controls (40.7±3.3 U/g tissue). However, serum arginase
activity did not show any significant change in both groups. Finally, the micromethod used to quantify arginase activity in
this study is superior to other methods because it has increased sensitivity, requires less sample, and is less time-consuming.
Arginase differences are significant, according to the t-test (P<0.05).
Received: 14 September 2001 / Accepted: 6 February 2002 相似文献
The study objectives were to determine (i) if pre-ovulatory luteinizing
hormone (LH) surges, undetected in urine by two immunoradiometric assays
(IRMA), were detectable by an ultrasensitive immunofluorometric assay
(IFMA) and (ii) the influence of creatinine adjustment on the detection and
timing of the urinary LH surges. Daily urine specimens were contributed by
healthy 25-36 year old volunteers during 14 ovulatory menstrual cycles for
an epidemiological study conducted in 1983-1985. Specimens were selected as
having been previously assayed by two IRMA without consistently detecting
LH surges. These urine specimens were remeasured using an IFMA and adjusted
for creatinine concentration. IFMA measurements revealed unambiguous LH
surges in all cycles. Adjusting IRMA urinary LH values for creatinine
concentrations revealed previously undetected LH surges in four of eight
cycles. Creatinine adjustment also altered the timing of IRMA and IFMA LH
surges by 1-5 days. These results demonstrate an IFMA that detects pre-
ovulatory LH surges in unpreserved, frozen urine from cycles where such
surges were previously undetectable. Further, creatinine adjustment can
markedly affect detection and timing of the onset and peak of the urinary
LH surge. While our analysis suggests that this adjustment improves the
validity of the LH measure, this requires further investigation.
相似文献
Genomic DNA from 19 Japanese patients with congenital lipoid adrenal
hyperplasia (lipoid CAH) representing 16 different families was examined to
identify the genetic alterations of steroidogenic acute regulatory protein
(StAR). Ten of 19 patients had a 46,XX karyotype and nine had a 46,XY
karyotype. Six of the 46,XX patients have experienced spontaneous pubertal
changes including breast development and irregular menstruation whereas
none of the 46,XY subjects displayed pubertal changes. Eight different
mutations were identified. Sixteen patients were either homozygotes or
compound heterozygotes for the Q258X mutation. The seven other mutations
identified were 189delG, 246insG, 564del13bp, 838delA, Q212X, A218V and
M225T. The 189delG, 246insG, 546del13bp and Q212X mutants encode truncated
proteins. COS-1 cells transfected with expression vectors encoding cDNAs
for the mutant StAR proteins which affect the C-terminus, 838delA, A218V
and Q258X, exhibited no steroidogenesis enhancing activity. However, the
M225T mutant retained some steroidogenic activity. The patient with the
M225T mutation had late onset of this disorder and some capacity to secrete
testosterone in response to hCG. These findings suggest: (i) that the Q258X
mutation can be used as a genetic marker for the screening of Japanese for
lipoid CAH, (ii) that the C-terminus of StAR plays an important role in the
protein's activity and (iii) that there are differences in the extent of
functional impairment of the testis and ovaries in lipoid CAH.
相似文献
The aim of this study was to compare the efficacy of pure follicle
stimulating hormone (FSH) with that of FSH/human menopausal gonadotrophin
(HMG) combination in downregulated cycles. A total of 357 patients was
evaluated retrospectively. Sixty percent of patients in the FSH group and
55% in the FSH/HMG group were new; the others were repeat patients.
Ovulation was suppressed with leuprolide acetate in all patients, followed
by either FSH (n = 218) or FSH/HMG (n = 119). There was no difference in
patients' age, infertility factors, number of ampoules used, length of
stimulation, oestradiol levels on day of human chorionic gonadotrophin
(HCG) administration, number of oocytes recovered or the number of embryos
transferred. Also, nuclear maturity at aspiration and fertilization rates
were not different between the two groups. FSH stimulation resulted in a
significantly higher percentage of mature oocytes that showed the typical
'mature' morphological characteristics (P < 0.0001). The clinical
pregnancy rates per transfer were 40 and 28% in patients stimulated with
pure FSH and FSH/HMG respectively (P < 0.05). The significantly higher
number of immature oocytes matured in vitro in the FSH/HMG group (P =
0.001) suggests a possible effect on in-vitro maturation, due to
luteinizing hormone present in HMG. The difference in mature oocyte quality
may be an important determinant in the higher pregnancy rates for the FSH-
stimulated patients.
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To resolve the controversy over the immunologic nature of nodular mixed lymphoma (NM), we examined nine cases of NM for surface antigens using both tissue section and cell suspension methods. These were contrasted with 12 cases of nodular poorly differentiated lymphocytic lymphoma. We found two major B cell types of NM, those with monoclonal immunoglobulin (SIg+)-positive nodules with an SIg+B1+B2+Ia+T- phenotype (four cases) and those with nodules devoid of immunoglobulin with an SIg-B1+B2-Ia+T- phenotype (five cases). Our SIg+ NM cases appear similar to nodular poorly differentiated lymphocytic lymphoma (SIg+B1+B2+Ia+T-), except suspension assay indicates fewer SIg+ cells in NM. In our SIg- NM cases, the neoplastic nodules consistently expressed B1 and Ia-like antigens and lacked T cells, indicating a B cell neoplasm similar to many large cell lymphomas. By demonstrating a B cell antigen in SIg- nodules, we substantially resolve the controversial NM cases previously called "null" or T cell. The two distinct immunotypes indicate the complexity of B cell antigenic expression in NM and might also explain the variable response to therapy in NM described in previous studies. Finally, we describe NM cases with the simultaneous occurrence of several stages of B cell differentiation. This suggests that some NM cases are not frozen in a single stage of B cell development but may express a range of B cell antigens. NM, then, may be a paradigm of variable, simultaneous B cell maturation. 相似文献