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71.
Induction of B cell apoptosis by co-cross-linking CD23 and sIg involves aberrant regulation of c-myc and is inhibited by bcl-2 总被引:2,自引:0,他引:2
Campbell KA; Studer EJ; Kilmon MA; Lees A; Finkelman F; Conrad DH 《International immunology》1997,9(8):1131-1140
A novel system to study the effects of co-cross-linking CD23/FceRII and sIg
on murine B lymphocytes utilizes a highly multivalent form of anti- Ig
prepared by covalently linking anti-Ig antibodies to a DNP-dextran
backbone. CD23-sIg co-cross-linking is accomplished by the addition of
DNP-specific monoclonal IgE. Previous studies demonstrated that co-
cross-linking CD23 and sIg significantly inhibited mouse B cell
proliferation, especially at high doses of the multivalent anti-Ig.
Interestingly, examination of early activation signals reveals no
difference in B cells subjected to co-cross-linking conditions as compared
to B cells activated with anti-Ig alone. Total cellular protein tyrosine
phosphorylation levels are unchanged by co-cross- linking. Analysis of B
cell mRNA reveals that co-cross-linking the receptors does not alter the
expression levels of ornithine decarboxylase 8 h after stimulation as
compared to the controls. In contrast, levels of the proto-oncogene c-myc
were significantly elevated 1 h after inducing B cell activation under
co-cross-linking conditions. However, it remains unclear whether this
aberrant c-myc regulation plays any role in inducing apoptosis. In
addition, on day 3 after stimulation, the co-cross-linking of CD23 and sIg
resulted in the formation of apoptotic B cells, determined by both
photomicroscopy of the B cell cultures and FACS analysis of B cell nuclei.
B cells obtained from bcl-2 transgenic mice proliferated as well as
controls, and failed to undergo apoptosis when CD23 and sIg were
co-cross-linked on their surface. These studies indicate that
co-cross-linking of CD23 with B cell sIg inhibits B cell proliferation by a
mechanism that is distinct from that seen by co-cross-linking of the Fc
gamma RII and sIg. In addition, these results suggest a means by which
antigen- specific IgE can down-regulate additional B cell activation and
IgE synthesis.
相似文献
72.
Tariquidar-induced P-glycoprotein inhibition at the rat blood-brain barrier studied with (R)-11C-verapamil and PET. 总被引:1,自引:0,他引:1
Jens P Bankstahl Claudia Kuntner Aiman Abrahim Rudolf Karch Johann Stanek Thomas Wanek Wolfgang Wadsak Kurt Kletter Markus Müller Wolfgang L?scher Oliver Langer 《Journal of nuclear medicine》2008,49(8):1328-1335
The multidrug efflux transporter P-glycoprotein (P-gp) is expressed in high concentrations at the blood-brain barrier (BBB) and is believed to be implicated in resistance to central nervous system drugs. We used small-animal PET and (R)-11C-verapamil together with tariquidar, a new-generation P-gp modulator, to study the functional activity of P-gp at the BBB of rats. To enable a comparison with human PET data, we performed kinetic modeling to estimate the rate constants of radiotracer transport across the rat BBB. METHODS: A group of 7 Wistar Unilever rats underwent paired (R)-11C-verapamil PET scans at an interval of 3 h: 1 baseline scan and 1 scan after intravenous injection of tariquidar (15 mg/kg, n = 5) or vehicle (n = 2). RESULTS: After tariquidar administration, the distribution volume (DV) of (R)-11C-verapamil was 12-fold higher than baseline (3.68 +/- 0.81 vs. 0.30 +/- 0.08; P = 0.0007, paired t test), whereas the DVs were essentially the same when only vehicle was administered. The increase in DV could be attributed mainly to an increased influx rate constant (K1) of (R)-11C-verapamil into the brain, which was about 8-fold higher after tariquidar. A dose-response assessment with tariquidar provided an estimated half-maximum effect dose of 8.4 +/- 9.5 mg/kg. CONCLUSION: Our data demonstrate that (R)-11C-verapamil PET combined with tariquidar administration is a promising approach to measure P-gp function at the BBB. 相似文献
73.
74.
Recently, the separate trajectories of pharmacy benefit management and pharmacogenomics converged. Pharmacogenomic tests have become more widely available for clinical use and at costs within the range of typical health care services. Pharmacy benefit payers continue to seek the precision they can apply to their coverage policies and clinical programs that pharmacogenomics offers. We describe how pharmacogenomics can now make sense as part of a pharmacy benefit and also how pharmacogenomics can be applied in a benefit coverage policy and clinical programs. Detail is provided on clinical program development and implementation processes featuring pharmacogenomics. We also discuss the research needed to support ongoing program development involving pharmacogenomics and describe the current roles of benefit payers and administrators in these research efforts. The legal and ethical dimensions of applying pharmacogenomics in pharmacy benefits are covered and in particular how benefit payers and administrators need to navigate between genetic exceptionalism and applicable laws and regulations. Finally, some thoughts are provided on future opportunities and challenges for pharmacogenomics in pharmacy benefit management and pharmacy in general. 相似文献
75.
Perforated colorectal neoplasms: correlation of clinical, contrast enema, and CT examinations 总被引:2,自引:0,他引:2
Hulnick DH; Megibow AJ; Balthazar EJ; Gordon RB; Surapenini R; Bosniak MA 《Radiology》1987,164(3):611-615
Results of clinical, contrast enema (CE), and computed tomographic (CT) examinations in 39 patients with perforated colorectal neoplasms were retrospectively reviewed. Twenty patients were toxemic at initial presentation, but in only four patients was the diagnosis of perforated colorectal neoplasm initially suspected clinically. CE study was performed in 22 patients and enabled the diagnosis of perforated neoplasm in 11 cases, neoplasm alone in eight, and neither neoplasm nor perforation in three. CT was performed in 38 patients and enabled the diagnosis of perforated neoplasm in 36; pericolic phlegmon but no mass lesion was evident in two. In 16 patients, CT also demonstrated metastatic disease. Because of its reliability in establishing the diagnosis and staging the extent of the inflammatory and neoplastic disease, CT is indicated in cases of suspected or proved perforated colorectal neoplasm and in cases in which CE study findings are indeterminate or suggestive of perforated neoplasm. 相似文献
76.
77.
A Holden JEM Anderson FJ Ives D Taylor EJ Wylie FRACR R Adamson 《Journal of Medical Imaging and Radiation Oncology》1996,40(4):391-397
The early clinical experience with a 3-Dimensional Fourier Transform Gradient Echo sequence with fat suppression in the evaluation of breast masses is reported. Ten female patients with breast malignancies were pre-operatively evaluated with this sequence and the results compared with the pathological specimens. The scanning protocol included a noncontrast sequence followed by an immediate post-contrast sequence (completed 4.5 min after intravenous contrast injection) and a delayed sequence. Images were assessed for maximum lesion and parenchymal enhancement, lesion size and additional enhancing abnormalities. In six patients, malignant masses enhanced maximally on the immediate post-contrast sequence with parenchyma enhancing maximally on delayed images. In three cases, there was preferential enhancement of malignant lesions over normal parenchyma but to a similar degree on both post-contrast sequences. In one case, both the lesion and parenchyma enhanced maximally on the delayed sequence. Magnetic resonance assessed lesion size accurately and also detected satellite malignancies in one case. However, lesion grade, associated in situ carcinoma and lymphovascular invasion did not impact on lesion enhancement. In this small series, a contrast-enhanced, fat-suppressed 3-D Gradient Echo Sequence detected breast carcinoma with high sensitivity. The technique holds promise but further evaluation is required. 相似文献
78.
Van Someren EJ 《Experimental gerontology》2000,35(9-10):1229-1237
The incidence of disturbed sleep is strongly increased in healthy and demented elderly. Age-related alterations in the circadian timing system appear to contribute strongly to these problems. With increasing age, a lack of input to the suprachiasmatic nucleus (SCN), the biological clock of the brain, may accelerate de-activation of neurons involved in the generation of 24-h rhythm or output of this rhythm. This process appears to be reversible, since supplementation of stimuli that impinge on the SCN can re-activate these neurons and ameliorate disturbances in the sleep–wake rhythm. 相似文献
79.
目的 通过凝血酶对成骨细胞的增殖及分化作用的研究来探讨受体介导的凝血酶的功能.方法 原代成骨细胞分别取自于蛋白酶激活受体(protease-activated receptor,PAR)-1敲除鼠和野生对照鼠的头颅骨.并利用凝血酶,人工合成的PAR-1或PAR-4特异性激活短肽对细胞进行处理,通过对5.溴-2-脱氧尿嘧啶的嵌入及细胞碱性磷酸酶活性的测定探讨PAR-1或PAR-4激活对细胞增殖和分化的影响.结果 在野生鼠成骨细胞,凝血酶及PAR-1激活肽均能促进的细胞增殖和降低碱性磷酸酶的活性,但PAR-4激活肽却无这些作用.然而在PAR-1 敲除鼠的成骨细胞无论是凝血酶还是PAR-4激活肽均不能改变细胞的增殖及碱性磷酸酶的活性.结论 本研究结果 表明凝血酶促进成骨细胞增殖及抑制其分化是通过PAR-1介导的.其他凝血酶受体并不具有此作用. 相似文献
80.
Thomas Roland Terrell Roberd M Bostick Ruth Abramson Dawen Xie William Barfield Robert Cantu Michele Stanek Trina Ewing 《Clinical journal of sport medicine》2008,18(1):10-17
OBJECTIVE: To investigate associations of APOE, APOE promoter (G-219T), and tau protein exon 6 polymorphisms (47 and 53) and a history of self-reported concussion in college athletes. DESIGN: Multi-center cross-sectional study. SETTING: Male football and male and female soccer programs at the University of South Carolina, Jacksonville University, Benedict College, and the College of Charleston. PARTICIPANTS: Active 18- to 30-year-old (n = 195) intercollegiate male football players and male and female soccer players during 2001 and 2002. ASSESSMENT OF RISK FACTORS: Written questionnaires and blood or mouthwash samples for DNA for genotyping by RFLP/PCR. MAIN OUTCOME MEASUREMENT: Self-reported history of concussions over the previous 8 years. RESULTS: A statistically significant, nearly 3-fold increase in risk of a history of concussion for those with the APOE promoter G-219T TT genotype relative to the GG genotype (OR, 2.8; 95% CI, 1.1 to 6.9) adjusted for age, sport, school, and years in their primary sport, a finding that was stronger for Cantu grade 2 and 3 concussions. CONCLUSIONS: These results suggest that college athletes with an APOE promoter G-219T TT genotype may be at increased risk for having a history of concussions, especially more severe concussions. Although there was some support for the possibility that the tau 53 polymorphism may be associated with increased risk of prior concussion (OR, 2.1; 95% CI, 0.3 to 14.5), there was no support for an association with APOE genotypes. The results of this cross-sectional study support the need for a prospective study of genetic factors, such as APOE promoter polymorphisms, and the incidence of and sequelae from concussions in college athletes. 相似文献