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排序方式: 共有625条查询结果,搜索用时 31 毫秒
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S Hanke H Hanke M Oberhoff K K Haase S Hassenstein E Betz K R Karsch 《Zeitschrift für Kardiologie》1991,80(6):404-411
To determine the time-course of morphological changes after excimer laser treatment of atherosclerotic carotid arteries, laser angioplasty was performed in 34 rabbits after production of an intimal plaque (13 +/- 6 cell layers, 30 +/- 9% stenosis) using electrical stimulations. The animals were sacrificed 3, 7, 14, 21, 28, and 42 days after laser treatment. A total or subtotal thrombotic occlusion was found in four cases. No perforation was observed, but in 10 animals histological examination evidenced a partial ablation of the medial layer with signs of local thrombus formation and local reduction of SMC in the media. In five animals a stenosis of more than 50% of luminal reduction was due to intimal proliferation of smooth muscle cells (SMC), as determined by a monoclonal antibody against alpha-actin. After the initial ablation, a continuous increase of intimal cell layers was found, from 7 +/- 6 cell layers (19 +/- 9% stenosis) at 7 days, to 28 +/- 5 cell layers (45 +/- 18% stenosis) at 28 days following excimer laser angioplasty (p less than 0.01). After 42 days no additional increase of intimal thickening occurred. Our data suggest that incidence and morphology is comparable to the proliferative response of SMC following conventional balloon angioplasty. 相似文献
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Dao Yin Xie Stefan Hassenstein Martin Oberhoff Hartmut Hanke Andreas Baumbach Kristian Hohla Karl Konstantin Haase Karl Rüdiger Karsch 《Lasers in surgery and medicine》1993,13(6):618-624
A modified exeimer laser energy delivery system was used to irradiate 100 segments of normal and fibrous aorta in vitro. The laser beam was scanned into 8 fiber bundles consisting of 50 fibers each resulting in a reduction of the applied pulse energy. The total repetition rate was increased to 150 Hz in order to keep the repetition rate per fiber bundle close to 20 Hz and to minimize thermal injury. The results demonstrate that effective ablation (etch rate per 8 pulses > 2.0 μm) occurred at an energy fluency of 50 mJ/mm2 in both normal and fibrous aorta. Tissue damage (carbonization, tissue separation, fissures, cracks, and vacuolization) was in a range of 100 ± 28 to 152 ± 30 μm for normal aorta and in a range of 57 ± 35 to 110 ± 39 μm for fibrous aorta. We conclude that effective ablation of normal and fibrous human aorta can be achieved by the application of smooth excimer laser coronary angioplasty. This improvement of excimer laser technology may result in a reduction of shock wave- and cavitation-induced damage leading to a reduction of tissue injury. However, this awaits further in vitro and in vivo confirmation. © 1993 Wiley-Liss, Inc. 相似文献
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Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability 总被引:1,自引:15,他引:1
La Spada AR; Peterson KR; Meadows SA; McClain ME; Jeng G; Chmelar RS; Haugen HA; Chen K; Singer MJ; Moore D; Trask BJ; Fischbeck KH; Clegg CH; McKnight GS 《Human molecular genetics》1998,7(6):959-967
X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG
repeat expansion in the first exon of the androgen receptor (AR) gene.
Disease-associated alleles (37-66 CAGs) change in length when transmitted
from parents to offspring, with a significantly greater tendency to shift
size when inherited paternally. As transgenic mice carrying human AR cDNAs
with 45 and 66 CAG repeats do not display repeat instability, we attempted
to model trinucleotide repeat instability by generating transgenic mice
with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions
in their genomic context. Studies of independent lines of AR YAC transgenic
mice with CAG 45 alleles reveal intergenerational instability at an overall
rate of approximately 10%. We also find that the 45 CAG repeat tracts are
significantly more unstable with maternal transmission and as the
transmitting mother ages. Of all the CAG/CTG repeat transgenic mice
produced to date the AR YAC CAG 45 mice are unstable with the smallest
trinucleotide repeat mutations, suggesting that the length threshold for
repeat instability in the mouse may be lowered by including the appropriate
flanking human DNA sequences. By sequence-tagged site content analysis and
long range mapping we determined that one unstable transgenic line has
integrated an approximately 70 kb segment of the AR locus due to
fragmentation of the AR YAC. Identification of the cis - acting elements
that permit CAG tract instability and the trans -acting factors that
modulate repeat instability in the AR YAC CAG 45 mice may provide insights
into the molecular basis of trinucleotide repeat instability in humans.
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In a child with some features of Turner's syndrome, gonosomal mosaicism with an isodicentric nonfluorescent (idic)Y chromosome was detected (mos 45,X/47,X,idic(Y)(q11),idic(Y)(11)/46,X,idic(Y)(q11)). Histopathological examination showed streak gonads with some evidence of ovarian stroma and no sign of gonadoblastoma. Polymerase chain reaction (PCR) analysis in blood lymphocytes and gonadal tissues using primers of seven loci along the Y chromosome, including the sex determined region (SRY), azoospermia factor region (AZF) and the deleted in azoospermia ( DAZ ) gene was positive for all loci tested, confirming the isodicentric character of the Y chromosome and indicating the presence of the AZF region. It is remarkable that the existence of spermatogenesis controlling genes does not play an important role in gonadal development and differentiation in a phenotypic female with some Turner stigmata. The data presented here are briefly discussed with previously-described patients. 相似文献
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The effect of delayed graft function and immunosuppressive drugs on posttransplant erythropoiesis was studied prospectively in 18 living-related (LR) and 84 cadaver-donor (CD) recipients. Eight of 18 LR and 20 of 84 CD recipients received antilymphoblast globulin (ALG) in addition to azathioprine and prednisone. Sixty-four CD recipients received cyclosporine (CsA) with prednisone. In the absence of rejection reticulocytosis began 6.7 +/- 0.2 days following graft implantation in azathioprine-only-treated LR recipients. This was lengthened by ALG to 9.4 +/- 0.3 and 9.9 +/- 0.7 days in LR and CD recipients, respectively, whose grafts functioned immediately. Delayed graft function prolonged onset of reticulocytosis to 15.9 +/- 0.9 days in ALG-treated but not in CsA-treated recipients (5.8 +/- 0.4 days). The shortest latency was noted in CsA-treated recipients (4.9 +/- 0.5 days) with immediately functioning grafts. The earlier onset of reticulocytosis of CsA-treated recipients was followed by statistically significant blunting of peak reticulocytosis, which correlated with a slower rate of correction of anemia (delta Hct = 0.19/day) compared with non-CsA-treated recipients (delta Hct = 0.34/day). Early rejection was associated with abrogation of reticulocytosis and correction of anemia without regard to immunosuppressive regimen) until rejection was reversed. Erythropoietin (EPO) was measured sequentially in 5 patients with immediate function. In 4 of 5 cases changes in EPO preceded those in reticulocytosis. EPO rose from a mean of 13 mU/ml pretransplant to a peak of 50 within 3 weeks and decreased to 18 mU/ml within 6 weeks of graft implantation. At six months posttransplant, normalized reticulocyte counts were only 55% higher (1.75 vs. 1.13%) but hematocrit had increased from 26 +/- 1% to 42 +/- 1%. Hematocrit varied inversely with serum creatinine, which was highest in CsA-treated patients with initial delayed graft function. We conclude that correction of anemia posttransplantation is driven by EPO but other factors may also be important, that neither ATN nor ALG-therapy have clinically important effects on erythropoiesis, and that CsA reduced "effective" erythropoiesis and influences correction of anemia--particularly if delayed graft function complicates the initial course posttransplantation. 相似文献