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61.
U937 cells respond to a variety of stimuli with increased differentiation as manifested by reduced growth, increased adherence, increased expression of several surface receptors, and increased capacity for phagocytosis and formation of reactive oxygen intermediates. In the present study the effects of lymphocyte conditioned media, recombinant interferon-gamma (IFN-gamma), and 1 alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) on the ability to form reactive oxygen intermediates by U937 cells were measured by using the luminol-dependent luminescence (LDL) assay. Neither 1,25(OH)2D3 alone nor IFN-gamma alone enhanced competence for phorbol myristate acetate- stimulated LDL. Cells were capable of moderate LDL after exposure to lymphocyte conditioned media, and this was enhanced by 1,25(OH)2D3 (10(- 8) mol/L) and other vitamin D metabolites at higher concentrations. This effect was not secondary to accelerated production of myeloperoxidase, which is important in the LDL assay. Enhanced phorbol myristate acetate-stimulated phosphorylation of a 48-kd substrate was observed in 32P-labeled intact cells treated with 1,25(OH)2D3 alone or in combination with IFN-gamma. Treatment of cells with IFN-gamma or lymphocyte conditioned media did not alter phosphorylation. These results support the concept that 1,25(OH)2D3 plays a role in phagocyte differentiation and activation beyond the effects of lymphokines. Protein kinase C-mediated phosphorylation reactions may be necessary for the ability of U937 cells to reduce O2 and required for maximal activity under some conditions of incubation. 相似文献
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63.
Bash RO; Crist WM; Shuster JJ; Link MP; Amylon M; Pullen J; Carroll AJ; Buchanan GR; Smith RG; Baer R 《Blood》1993,81(8):2110-2117
Alteration of the TAL1 locus is the most common nonrandom genetic defect in childhood T-cell acute lymphoblastic leukemia (T-ALL). To determine if rearrangements of the TAL1 proto-oncogene confer a distinct leukemic phenotype, we studied leukemic peripheral blood or bone marrow samples from 182 children with newly diagnosed T-ALL enrolled on Pediatric Oncology Group treatment protocols. Forty-eight (26%) of the samples had a local rearrangement of the TAL1 locus. Demographic and clinical features were compared for patient subgroups with and without TAL1 rearrangements. The only clinical correlates that were significantly associated with TAL1 gene rearrangements were higher white blood cell count (P = .017) and higher hemoglobin (P = .007) at diagnosis. Immunophenotypically, samples with altered TAL1 were more likely to be CD2+ (P = .001) and lack CD10 (cALLa) expression (P = .007) than those without the rearrangement. There was a trend toward improved event-free survival (EFS) in patients with TAL1 rearrangements (4-year EFS was 44% +/- 7% for patients without the rearrangements v 59% +/- 11% for those with rearrangements), but the difference was not significant (P = .34). The role of TAL1 in leukemogenesis has yet to be clearly defined, and the prognostic significance of TAL1 gene rearrangements in T-ALL deserves further study. 相似文献
64.
Mid-trimester loss--appraisal of a screening protocol 总被引:1,自引:0,他引:1
The main causes for mid-trimester loss are known. There is likely to be
overlap with those of first trimester loss, but the proportions may be
different. We wished to perform an aetiological survey in a large
population of patients with a history of recurrent miscarriage, for
possible explanations for their second trimester miscarriages. Database
analysis of 636 patients attending a UK University Teaching Hospital
dedicated miscarriage clinic between 1991 and 1996 revealed a 25%
prevalence (n = 158) for second trimester miscarriage. Results from an
investigative screening protocol were positive in 50% of cases: 33% (n =
52) tested positive for antiphospholipid syndrome (APS); 8% (n = 13)
fulfilled strict criteria for cervical incompetence; there was a 4%
prevalence of uterine anomaly; 3% for infection (n = 5) and 2% of patients
(n = 3) proved to be hypothyroid. Importantly, dual pathology was found in
5% of patients with a history of second trimester miscarriage. As
idiopathic mid-trimester loss is a diagnosis by exclusion, a high index of
suspicion is required, as are modern diagnostic techniques.
相似文献
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GERD FRÖHLIG ARMIN BOLZ JÖRG STRÖBEL MARTIN RUTZ PETER LAWALL HOLGER SCHWERDT MAX SCHALDACH HERMANN SCHIEFFER 《Pacing and clinical electrophysiology : PACE》1998,21(6):1239-1246
Minimizing the geometric surface area of pacing electrodes increases impedance and reduces the current drain during stimulation, provided that voltage (pulse-width) thresholds remain unchanged. This may be feasible by coating the electrode surface to increase the capacity of the electrode tissue interface and to diminish polarization. Ten unipolar, tined leads with a surface area of 1.3 mm2 and a “fractal” coating of Iridium (Biotronik SD-V137) were implanted in the ventricle, and electrogram amplitude (unfiltered), slew-rate, pacing threshold (0.5 ms), and impedance (2.5 V; 0.5 ms) were measured by the 5311 PSA (Medtronic). On days 0, 2, 5, 10, 28, 90, 180, 360 postimplant, sensing threshold (up to 7.0 mV, measuring range 1–14 mV on day 360 only) and the strength duration curve (0.5–4.0 V; 0.03–1.5 ms; steps: 0.5 V; 0.01 ms, respectively) were determined, the minimum charge delivered per pulse (charge threshold), and the impedance were taken from pacemaker telemetry (Intermedics 294–03). Data were compared with those of an earlier series of 20 unipolar, tined TIR-leads (Biotronik) with a surface area of 10 mm2 and a “fractal” coating of titanium nitride. With the model SD-V137 versus TIR, intraoperative electrogram amplitudes were 15.1 ± 6.1 versus 14.4 ± 3.9 mV(NS), slew rates 3.45 ± 1.57 versus 1.94 ± 1.06 V/s (P < 0. 05), pacing thresholds 0.16 ± 0.05 versus 0.52 ± 0.15 V (P < 0.01) and impedance measurements 1,136 ±175 versus 441 ± 73 Ω (P < 0.0001), respectively. During follow-up, sensing thresholds were the same with both leads. Differences in pulse width thresholds lost its significance on day 28 but resumed on day 360 (SD-V137: 0.08 ± 0.04 ms; TIR: 0.16 ± 0.06 ms at 2.5 V; P < 0.01). With an electrode surface of 1.3 mm2, charge per pulse and impedance consistently differed from control, beingO.15 ± 0.15 versus 0. 66 ± 0. 20 μC (P < 0.001) and 1,344 ± 376 versus 538 ± 79 Ω, respectively, one year after implantation (P < 0.0001). In summary, “fractally” coated small surface electrodes do not compromise sensing; by more than doubling impedance against controls they offer pacing thresholds (mainly in terms of charge) that are significantly lower than with the reference electrode. 相似文献
68.
HENDRIK BONNEMEIER JASMIN ORTAK RALPH TÖLG† MAREN WITT JÖRG SCHMIDT UWE K.H. WIEGAND FRANK BODE HERIBERT SCHUNKERT GERT RICHARDT† 《Pacing and clinical electrophysiology : PACE》2005,28(S1):S217-S221
Beta-adrenergic blockers exert significant antiarrhythmic activity during ischemia and reperfusion. To further explore the beneficial effects conferred by alpha-1-adrenoceptor blockade on ventricular repolarization dynamicity in the acute phase of myocardial infarction (AMI), we compared carvedilol with metoprolol in the setting of primary percutaneous coronary intervention (PCI). In a prospective study, 100 consecutive patients undergoing primary PCI for AMI were randomized to metoprolol 200 mg/day versus carvedilol 25 mg/day. The first oral dose of study drug was administered and a 24-hour ambulatory electrocardiogram recorded upon hospital admission. Slopes of the linear QT/RR regression were determined before and after reperfusion. A total of 38 recordings of patients treated with metoprolol and 34 recordings of patients with carvedilol were eligible for analysis of QT/RR slopes. The two study groups were similar with respect to age, gender, TIMI perfusion grades, ventricular function, duration of ischemia, and site and size of infarction. Mean RR- and QT-intervals were similar to the metoprolol and carvedilol groups, before and after PCI. Likewise, there was no significant difference in QT/RR slopes between the metoprolol and carvedilol groups before PCI. In contrast, after PCI, there was a trend toward lower QT/RR slopes in the metoprolol group (from 0.18 ± 0.07 to 0.17 ± 0.08), and a significant decrease in QT/RR slopes in the carvedilol group (from 0.17 ± 0.07 to 0.14 ± 0.09). In patients undergoing successful direct PCI for AMI, treatment with carvedilol, in contrast to metoprolol, was associated with a significant decrease in QT–RR slopes, suggesting greater cardiac electrical stability. 相似文献
69.
T-gamma lymphoproliferative disease (T-gamma LPD) is a chronic disorder of mature T cells that is associated with neutropenia and autoimmune phenomena. Although the progression of the lymphoproliferation is indolent, it is often associated with a monoclonal proliferation of T- cell-type large granular lymphocytes (LGL) that manifest multiple in vitro suppressor and cytotoxic activities. We considered the possibility that the granulocytopenia or anemia might represent an autoimmune disorder mediated by the monoclonal LGL via T-cell receptor (TCR) recognition of an antigen involved in hematopoiesis. Therefore, in an effort to characterize the usage of the TCR alpha- and beta-chain genes in patients with T-gamma LPD, we cloned and sequenced TCR alpha- and beta-chain mRNAs derived from the T-cell type LGL of five patients. The five patients studied did not use a common V alpha nor a common J alpha segment. However, an unusual finding was observed in one of the patients where the occurrence of a single variable-diversity-junctional (VDJ) rearrangement of the beta chain confirmed the monoclonal origin of the LGL proliferation. In accord with this evidence for monoclonality, many of the cells studied used a common V alpha (V alpha 19.1). In contrast to this common V alpha usage, there was a marked diversity of the J alpha segments and N-region addition that were associated with the V alpha 19.1 segment. This pattern of common V alpha usage associated with different N and J alpha segments suggests an immune-mediated selection process affecting the TCR alpha chain occurring after the transformation event that established the clone. We suggest that the T-cell-type LGL malignant clone might have developed autoreactivity conferred by the selected TCR alpha chain and that this autoreactivity might be implicated in this patient's anemia. 相似文献
70.
JÚRG SCHLÄPFER M.D. LUKAS KAPPENBERGER M.D. MARTIN FROMER M.D. 《Journal of cardiovascular electrophysiology》1996,7(5):445-449
RF Ablation-Induced Bezold-Jarisch Phenomenon. We report a case of asystole induced by radiofrequency (RF) ablation via the coronary sinus in a 35-year-old man suffering from symptomatic left posteroseptal accessory pathway. RF application provoked progressive slowing of the sinus rhythm, disappearance of the preexcitation, and an 8-second period of asystole followed by atrial fibrillation. The causal mechanism proposed is a strong stimulation of va-gal afferent pathways linked with sensory endings of the inferoposterior myocardial wall leading to a Bezold-Jarisch-like phenomenon. 相似文献