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Johannes Irsch Rudolf Hendriks Hans Tesch Ruud Schuurman Andreas Radbruch 《European journal of immunology》1993,23(2):481-486
In activated murine B lymphocytes, immunoglobulin class switch recombination occurs as a highly regulated process which is targeted to distinct switch regions. Here we present first evidence that in human B lymphocytes, switch recombination is targeted to distinct switch regions as well. In a panel of clonally unrelated IgG1-expressing human B cells, immortalized by Epstein-Barr virus (EBV) transformation, seven out of nine cells show switch recombination between Sμ and Sγ1 on both alleles, the active and inactive one. The remaining cells show no switch recombination on the inactive IgH locus. The very strong correlation of switch recombination on both alleles of IgG1-expressing cells proves that class switch recombination to IgG1 is not random but directed in human B lymphocytes. 相似文献
4.
Summary Muscle force recovery from short term intense exercise was examined in 16 physically active men. They performed 50 consecutive
maximal voluntary knee extensions. Following a 40-s rest period five additional maximal contractions were executed. The decrease
in torque during the 50 contractions and the peak torque during the five contractions relative to initial torque were used
as indices for fatigue and recovery, respectively. Venous blood samples were collected repeatedly up to 8 min post exercise
for subsequent lactate analyses. Muscle biopsies were obtained from m. vastus lateralis and analysed for fiber type composition,
fiber area, and capillary density.
Peak torque decreased 67 (range 47–82%) as a result of the repeated contractions. Following recovery, peak torque averaged
70 (47–86%) of the initial value.
Lactate concentration after the 50 contractions was 2.9±1.3 mmol·l−1 and the peak post exercise value averaged 8.7±2.1 mmol·l−1. Fatigue and recovery respectively were correlated with capillary density (r=−0.71 and 0.69) but not with fiber type distribution. A relationship was demonstrated between capillary density and post
exercise/peak post exercise blood lactate concentration (r=0.64). Based on the present findings it is suggested that lactate elimination from the exercising muscle is partly dependent
upon the capillary supply and subsequently influences the rate of muscle force recovery.
Dr. Tesch was on leave from Department of Clinical Physiology, Karolinska Hospital, Stockholm, Sweden 相似文献
5.
Immunomagnetic enrichment and detection of isolated tumor cells in bone marrow of patients with epithelial malignancies 总被引:5,自引:0,他引:5
Weihrauch MR Skibowski E Draube A Geller A Tesch H Diehl V Bohlen H 《Clinical & experimental metastasis》2002,19(7):617-621
The detection of isolated tumor cells (ITC) in the bone marrow of patients with epithelial malignancies is an independant
prognostic factor for several entities as breast cancer, colorectal cancer or non-small lung cancer. However, with conventional
immunocytology using Ficoll density gradient and APAAP staining, only a small proportion of the bone marrow samples can be
scanned for cytokeratin-positive (CK+) cells. To improve detection rates, we evaluated the enrichment of ITC by magnetic activated
cell sorting (MACS) compared to regularly stained cytospins. Recovery experiments with a CK+ breast cancer cell line (SKBR3)
were performed to calculate the MACS enrichment rate. Bone marrow was obtained by aspiration from 20 patients with carcinomas
of epithelial origin and from 17 controls. ITC were enriched and stained with magnetically labeled CAM 5.2 antibodies directed
to cytokeratin 7 and 8. MACS of SKBR3 seeded in peripheral blood revealed average recovery rates of 62% and 48% and average
enrichment factors of 104-fold and 8139-fold of the CK+ cells after one and after two separations, respectively. After immunomagnetic
enrichment, CK+ cells were detected in 16 of 20 (80%) cancer patients, whereas only 7 (35%) patients showed CK+ cells without
magnetic enrichment (P=0.002). Ten of twelve (83%) patients with metastatic disease (stage M1) and six of eight (75%) patients without any overt metastases (M0) had CK+ cells in their bone marrow. None of the negative controls showed any CK+ cells. Enrichment with magnetically labeled
anti cytokeratin antibodies increases the detection rate of epithelial cells in bone marrow of cancer patients compared to
immunocytology.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Within a muscle there is large variation in the activity of various enzymes among single fibres. It is reasonable, therefore, to expect a corresponding variation in their metabolic response to exercise. This was examined by obtaining muscle biopsies from five men at rest and after intense short-term exercise consisting of three bouts of 30 knee extensions each and intervened by 60 s rest. Freeze-dried dissected single fibres identified as type 1 or type 2 were analysed for ATP and IMP contents by liquid chromatography. Rest. Average ATP tended to be higher in type 2 than in type 1 fibres. The ATP range was 14-30 and 14-32 mmol X kg-1 dry muscle (dm) in type 1 and 2 fibres, respectively. IMP was less than 1 mmol X kg-1 dm in most fibres and similar in types 1 and 2. Exercise. Muscle force decreased 70% during exercise. The average decrease in ATP content was significant for both fibre types with somewhat larger response for type 2 (20%) than type 1 (10%) fibres. The ATP range was 10-28 and 10-30 mmol X kg-1 dm in type 1 and 2 fibres, respectively. Average IMP content increased substantially in both fibre types, more so for type 2, and the range for individual fibres was 0-13 (type 1) and 0-21 (type 2) mmol X kg-1 dm. Conclusion. After exhaustive short-term exercise, a large variation in ATP and IMP contents was evident among single type 1 and type 2 fibres. None of the fibres, however, showed an ATP content lower than 10 mmol X kg-1 dm.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
7.
Infection of B cells with Epstein-Barr Virus (EBV) induces interleukin-10 (IL-10) production, which may contribute to transformation. IL-10 can modulate the immune response at certain levels, playing a crucial role in balancing humoral and cellular responses. Moreover, it can function as a growth and differentiation factor for B cells. However, the mechanism of IL-10 induction is still unclear. Here we demonstrate that IL-10 was specifically induced by the EBV-latent membrane protein 1 (LMP1) in Burkitt's lymphoma (BL) cell lines BL2 and BL41. In two T cell lines (Jurkat, MOLT3), two NHL cell lines (U266, MHH-PREB1), or three Hodgkin's disease (HD) cell lines (L428, L540, and KMH2), LMP1 did not induce IL-10 expression. In contrast, LMP1 activated CD40 or CD54 (ICAM1) expression in the analyzed cell lines. LMP1 derivatives lacking the C-terminal activation regions (CTAR), by deletion of the amino acids between 187 and 351 (Delta CTAR1) or 232 and 386 (Delta CTAR2), alone, or together induced IL-10 at very low amounts compared to wild-type LMP1. Inhibition of LMP1-mediated NF kappa B activation by constitutive repressive I kappa B-alpha only marginally impaired IL-10 expression in BL2 cells, while SB2035080 at 5 microM (a specific p38/SAPK2 inhibitor) led to reduced IL-10 expression. Our findings confirm the role of LMP1 in transactivation of cellular genes possibly important for tumor immunoescape but show that more than one signaling pathway is involved in this activation and suggests the necessity of a defined conformation of CTARs to activate IL-10 involving p38/SAPK2. 相似文献
8.
Cytogenetic and clinical data of 11 patients with de novo myelodysplastic syndromes and partial or total trisomy of the long arm of chromosome 1 are presented. In eight of these patients trisomy 1q was the sole karyotypic change and therefore can be classified as a primary chromosome anomaly. A remarkably young median age of 36.5 years was noticed in this patient group. 相似文献
9.
P. A. Tesch A. Ekberg D. M. Lindquist J. T. Trieschmann 《Acta physiologica (Oxford, England)》2004,180(1):89-98
Aim: The efficacy of a mechanical, gravity‐independent resistance exercise (RE) system to induce strength gains and muscle hypertrophy was validated. Designed for space crew in orbit, this technique offers resistance during coupled concentric and eccentric actions by utilizing the inertia of a rotating flywheel(s), set in motion by the trainee. Methods: Ten middle‐aged (30–53 years) men and women performed four sets of seven maximal, unilateral (left limb) knee extensions two or three times weekly for 5 weeks. Knee extensor force and electromyographic (EMG) activity of the three superficial quadriceps muscles were measured before and after this intervention. In addition, with the use of magnetic resonance imaging (MRI), volume of individual knee extensor and ankle plantar flexor muscles was assessed. Results: Over the 12 training sessions, the average concentric (CON) and eccentric (ECC) force generated during exercise increased by 11% (P < 0.05). Likewise, maximal isometric strength (maximal voluntary contraction, MVC) at 90 and 120° knee angle increased by (P < 0.05) 11 and 12% respectively, after training. Neither individual quadriceps muscle showed a change (P > 0.05) in maximal integrated EMG (iEMG) activity. Quadriceps muscle volume increased by 6.1% (P < 0.05). Although the magnitude of response varied, all individual quadriceps muscles showed increased (P < 0.05) volume after training. As expected, ankle plantar flexor volume of the trained limb was unchanged (P > 0.05). Likewise, MVC, CON and ECC force, iEMG and knee extensor and plantar flexor muscle volume were unaltered (P > 0.05) in the right, non‐trained limb. Conclusion: The results of this study show that the present RE regimen produces marked muscle hypertrophy and important increases in maximal voluntary strength and appears equally effective as RE paradigms using gravity‐dependent weights, in this regard. 相似文献
10.
This study compared the career and domestic responsibilities of women physicians whose domestic partners were physicians (WP-Ps) with those of women physicians whose domestic partners were not physicians (WP-NPs). In 1988 the authors surveyed 602 women physicians in a large midwestern city regarding their career and domestic roles; 390 were physicians in training (students and residents), and 212 were physicians in practice (academic medicine and private practice). Overall, 382 (63%) responded; of the 382, 247 (65%) had domestic partners; of these 247, 91 (37%) were WP-Ps and 156 (63%) were WP-NPs. The WP-Ps were found to be twice as likely as the WP-NPs to interrupt their careers to accommodate their partners' careers. The WP-Ps also assumed significantly more domestic responsibilities and worked fewer hours practicing medicine than did the WP-NPs. The 163 women physicians in training (44-48%-of the WP-Ps and 119-76%-of the WP-NPs) demonstrated a more egalitarian division of labor overall, with no significant differences between the WP-Ps and the WP-NPs. The authors recommend that longitudinal studies be undertaken to determine whether women physicians in training continue this trend as they enter the practice of medicine. 相似文献