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排序方式: 共有470条查询结果,搜索用时 15 毫秒
91.
92.
Ultrasound findings in hepatitis 总被引:1,自引:0,他引:1
Kurtz AB; Rubin CS; Cooper HS; Nisenbaum HL; Cole-Beuglet C; Medoff J; Goldberg BB 《Radiology》1980,136(3):717
93.
94.
95.
QS Alex 755 nm激光对黑素细胞p16INK4a表达的影响 总被引:1,自引:0,他引:1
目的 了解激光对黑素细胞潜在恶变作用的可能性。方法 QS Alex 755nm激光体外照射HTB66、Sk-mel-24和G361 3种黑素瘤细胞株,照射剂量为0.85~2 J/cm^2,24h后收集细胞。应用流式细胞仪和RT-PCR方法分别测定p16INK4a蛋白和p16INK4a mRNA在激光照射前后和不同剂量照射后的表达水平。结果激光照射后,HTB 66细胞株(p16INK4a蛋白阳性株)的p16INK4a蛋白表达明显增加:而低水平表达的Sk-mel-24和G361细胞株无明显变化。在HTB66细胞株中虽然p16INK4a蛋白的表达上调,但对其功能的测定发现它并不能阻止细胞周期从G0/G1向S/G2M转变。HTB66细胞株的p16INK4a mRNA的表达也增加。结论经研究剂量的激光照射后DNA有损伤。具有黑素瘤家族史或个人史的患者可能有p16INK4a基因的突变或丢失,不提倡用激光治疗此类患者的色素性疾病。 相似文献
96.
CTLA-4 is required for the induction of high dose oral tolerance 总被引:5,自引:3,他引:5
Samoilova EB; Horton JL; Zhang H; Khoury SJ; Weiner HL; Chen Y 《International immunology》1998,10(4):491-498
Mucosal and systemic administrations of high dose antigens induce long-
lasting peripheral T cell tolerance. We and others have shown that high
dose peripheral T cell tolerance is mediated by anergy or deletion and is
preceded by T cell activation. Co-stimulatory molecules B7-1 (CD80)/B7-2
(CD86) and their counter-receptors CD28/CTLA-4 play pivotal roles in T cell
activation and immune regulation. In the present study, we examined the
roles of the B7 co-stimulation pathway in the generation of high dose
peripheral T cell tolerance. We found that blocking B7:CD28/CTLA-4
interaction at the time of tolerance induction partially prevented T cell
tolerance, whereas selective blockade of B7:CTLA-4 interaction completely
abrogated peripheral T cell tolerance induced by either oral or i.p.
antigens. These results suggest that CTLA-4-mediated feedback regulation
plays a crucial role in the induction of high dose peripheral T cell
tolerance.
相似文献
97.
Liu JQ; Bai XF; Shi FD; Xiao BG; Li HL; Levi M; Mustafa M; Wahren B; Link H 《International immunology》1998,10(8):1139-1148
Induction of mucosal tolerance by inhalation of soluble peptides with
defined T cell epitopes is receiving much attention as a means of
specifically down-regulating pathogenic T cell reactivities in autoimmune
and allergic disorders. Experimental autoimmune encephalomyelitis (EAE)
induced in the Lewis rat by immunization with myelin basic protein (MBP)
and Freund's adjuvant (CFA) is mediated by CD4+ T cells specific for the
MBP amino acid sequences 68-86 and 87-99. To further define the principles
of nasal tolerance induction, we generated three different MBP peptides
(MBP 68-86, 87-99 and the non- encephalitogenic peptide 110-128), and
evaluated whether their nasal administration on day -11, -10, -9, -8 and -7
prior to immunization with guinea pig MBP (gp-MBP) + CFA confers protection
to Lewis rat EAE. Protection was achieved with the encephalitogenic
peptides MBP 68-86 and 87-99, MBP 68-86 being more potent, but not with MBP
110-128. Neither MBP 68-86 nor 87-99 at doses used conferred complete
protection to gp-MBP-induced EAE. In contrast, nasal administration of a
mixture of MBP 68-86 and 87-99 completely blocked gp-MBP-induced EAE even
at lower dosage compared to that being used for individual peptides. Rats
tolerized with MBP 68-86 + 87-99 nasally showed decreased T cell responses
to MBP reflected by lymphocyte proliferation and IFN-gamma ELISPOT assays.
Rats tolerized with MBP 68-86 + 87-99 also had abrogated MBP-reactive
IFN-gamma and tumor necrosis factor-alpha mRNA expression in lymph node
cells compared to rats receiving MBP 110-128 nasally, while similar low
levels of MBP-reactive transforming growth factor-beta and IL-4 mRNA
expressing cells were observed in the two groups. Nasal administration of
MBP 68-86 + 87-99 only slightly inhibited guinea pig spinal cord
homogenate-induced EAE, and passive transfer of spleen mononuclear cells
from MBP 68-86 + 87-99-tolerized rats did not protect naive rats from EAE.
Finally, we show that nasal administration of MBP 68-86 + 87-99 can reverse
ongoing EAE induced with gp-MBP, although higher doses are required
compared to the dosage needed for prevention. In conclusion, nasal
administration of encephalitogenic MBP peptides can induce antigen-specific
T cell tolerance and confer incomplete protection to gp-MBP-induced EAE,
and MBP 68-86 and 87-99 have synergistic effects. Non-regulatory mechanisms
are proposed to be responsible for tolerance development after nasal
peptide administration.
相似文献
98.
目的了解成都市介水传染病流行状况和特征,做好水性疾病预警,同时掌握其分布规律和流行趋势,探讨水性疾病的控制策略。方法收集成都市2009年经水传播的肠道传染病及哨点医院症状监测结果,数据用χ^2检验进行统计学分析。结果成都市水性疾病构成主要以其他感染性腹泻和细菌性痢疾为主,两者占总发病数的93.01%,除1~3月发病率较低外,其他月份发病率均较高,但无统计学差异(5~12月发病率P〉0.05);发病人群以5岁以下散居儿童为主,哨点医院进行症状监测年发生率与成都市水性疾病年发生率相比无显著性差异(P〉0.05)。结论 5岁以下散居儿童为水性疾病的高危人群,水性疾病的控制可以其他感染性腹泻和细菌性痢疾为主进行相关性研究,而选择合适的医院门诊作为监测水性疾病的哨点,是一种切实可行的监测模式。 相似文献
99.
100.
Congenital Myocardial Sympathetic Dysinnervation (CMSD)—A Structural Defect of Idiopathic Long QT Syndrome 总被引:1,自引:0,他引:1
KONRAD GÖHL HERBERT FEISTEL REAS WEIKL KURT BACHMANN FRIEDRICH WOLF 《Pacing and clinical electrophysiology : PACE》1991,14(10):1544-1553
Concerning the pathogenetic mechanism of idiopathic long QT syndrome (LQTS), the hypothesis of a specific sympathetic imbalance has gained general acceptance, but its validity has never been proven. To test this hypothesis I-123-MIBG, an analogue of norepinephrine and guanethidine, was used to provide scintigraphic display of the efferent cardiac sympathetic innervation. Twelve members of four LQTS families (mean age 38.2 +/- 17.2 years, eight males) and eight healthy volunteers (mean age 48.2 +/- 13.3 years, five males) were studied by means of I-123-MIBG single photon emission computed tomography (SPECT). A quantitative analysis of all scans was performed. All scans of the healthy volunteers show a uniform tracer uptake with sometimes slightly decreased activity in the apex. (1) All patients with QTc greater than 440 msec (n = 5); (2) all, who had suffered from at least one episode of torsade de pointes, ventricular fibrillation (VF) or syncope (n = 5); and (3) all symptomatic patients with QTc prolongation (n = 4) have reduced or abolished (P less than 0.02) MIBG uptakes in the inferior and inferior septal parts of the left ventricle (congenital myocardial sympathetic dysinnervation [CMSD]). Additionally, one female without symptoms or QTc prolongation (LQT) shows an abnormal MIBG SPECT similar to the one of her daughter, who has LQT and symptoms. One male without LQT, who had suffered from VF shows CMSD similar to his father, who has LQT, but no symptoms. All members of the families with normal MIBG SPECTs have neither LQT nor symptoms. In all families CMSD fulfills the criteria of autosomal-dominant inheritance. Normal QTc-interval predicted only in 57% normal cardiac sympathetic innervation in the present LQTS families. Therefore, quantitative I-123-MIBG SPECT enables to identify myocardial sympathetic dysinnervation as structural defect in LQTS. CMSD is associated with and without LQT and presents a pattern of autosomal-dominant inheritance. LQT at rest or during exercise was specific (100%), but less sensitive (63%) in the assessment of CMSD than I-123-MIBG SPECT. 相似文献