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排序方式: 共有1593条查询结果,搜索用时 703 毫秒
11.
F. Parkes Weber 《Journal of the Royal Society of Medicine》1939,32(5):417-418
12.
Intestinal schistosomiasis japonica: CT-pathologic correlation 总被引:1,自引:0,他引:1
Lee RC; Chiang JH; Chou YH; Rubesin SE; Wu HP; Jeng WC; Hsu CC; Tiu CM; Chang T 《Radiology》1994,193(2):539
13.
14.
The effects of antioxidant supplementation during Percoll preparation on human sperm DNA integrity 总被引:20,自引:6,他引:20
Hughes CM; Lewis SE; McKelvey-Martin VJ; Thompson W 《Human reproduction (Oxford, England)》1998,13(5):1240-1247
The integrity of sperm DNA is crucial for the maintenance of genetic
health. A major source of damage is reactive oxygen species (ROS)
generation; therefore, antioxidants may afford protection to sperm DNA. The
objectives of the study were, first, to measure the effects of antioxidant
supplementation in vitro on endogenous DNA damage in spermatozoa using the
single cell gel electrophoresis (comet) assay and, second, to assess the
effect of antioxidant supplementation given prior to X-ray irradiation on
induced DNA damage. Spermatozoa from 150 patients were prepared by Percoll
centrifugation in the presence of ascorbic acid (300, 600 microM), alpha
tocopherol (30, 60 microM), urate (200, 400 microM), or acetyl cysteine (5,
10 microM). DNA damage was induced by 30 Gy X-irradiation. DNA strand
breakage was measured using the comet assay. Sperm DNA was protected from
DNA damage by ascorbic acid (600 microM), alpha tocopherol (30 and 60
microM) and urate (400 microM). These antioxidants provided protection from
subsequent DNA damage by X-ray irradiation. In contrast, acetyl cysteine or
ascorbate and alpha tocopherol together induced further DNA damage.
Supplementation in vitro with the antioxidants ascorbate, urate and alpha
tocopherol separately has beneficial effects for sperm DNA integrity.
相似文献
15.
Congenital mesoblastic nephroma: possible prognostic and management value of assessing DNA content. 总被引:1,自引:0,他引:1
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J C Barrantes C Toyn K R Muir S E Parkes F Raafat A H Cameron H B Marsden J R Mann 《Journal of clinical pathology》1991,44(4):317-320
The case records and pathology of all children with kidney tumours treated in the West Midlands Health Authority Region (WMHAR) from 1957 to 1986 were reviewed. The histology was reviewed by a panel of three paediatric pathologists. Thirteen (6%) out of 211 cases were considered to have congenital mesoblastic nephroma (CMN). Nine were of the conventional type, three of the atypical cellular type, and one mixed. DNA ploidy was investigated and showed two of the tumours to be aneuploid and nine diploid (tissue was not available in the two other cases). The two aneuploid tumours were of atypical cellular and mixed histology, respectively; the diploid tumours were of the conventional type in eight cases and atypical cellular in one. The atypical cellular type has been reported to behave more aggressively, but the benefit of additional treatment after surgery to prevent recurrence remains unclear. Measurement of DNA content by flow cytometry, together with histological subclassification, may be useful in selecting patients who will benefit from further treatment after surgery. 相似文献
16.
Kirkpatrick SE; Pitlick PT; Naliboff J; Friedman WF 《The American journal of physiology》1976,231(2):495-500
17.
Detection of chromosomes and estimation of aneuploidy in human spermatozoa using fluorescence in-situ hybridization 总被引:11,自引:0,他引:11
The development and application of fluorescence in-situ hybridization
(FISH) has opened the way for comprehensive studies on numerical chromosome
abnormalities in human spermatozoa. FISH can be rapidly applied to large
numbers of spermatozoa and thus overcomes the major limitation of
karyotyping spermatozoa after penetration of zona-free hamster oocytes. The
simultaneous hybridization of two or more chromosome-specific probes to
spermatozoa and subsequent detection of the bound probes using different
fluorescent detection systems enables two or more chromosomes to be
localized simultaneously in the same spermatozoon and provides a technique
for undertaking reasonable estimates of aneuploidy. The most commonly used
probes are those which bind to the centromeric region of specific
chromosomes. Most studies to date have concentrated on estimating
aneuploidy in spermatozoa from normospermic men, although reports are
beginning to appear on aneuploidy in spermatozoa from subfertile and
infertile men. Multi- probe FISH studies have generally reported disomy
(hyperhaploidy) estimates of 0.05-0.2% per chromosome. There is preliminary
evidence that some chromosomes such as X, Y and 21 are predisposed towards
higher rates of non-disjunction during spermatogenesis. There are also
suggestions of inter-donor variability in aneuploidy frequencies for
specific chromosomes, although this requires confirmation in larger
studies. While FISH is clearly a powerful technique that has many
applications in reproductive medicine, it must also be realized that it
does have limitations and the technology itself is still evolving and has
yet to be fully validated on spermatozoa.
相似文献
18.
SE Andrew 《Clinical genetics》2003,64(4):293-296
19.
Effects of retinol and hepatocyte-conditioned medium on cultured rat hepatic stellate cells 总被引:1,自引:0,他引:1
Hepatic stellate cells (HSC) become activated in liver injury, proliferating and secreting components of connective tissue. Activated HSC lose their native retinol and fat storing capacity. Signals from hepatocytes and/or Kupffer cells injured (eg, by iron overload) may contribute to the so-called activated HSC phenotype. Primary rat HSC cultures were treated with retinol to determine if this could produce a quiescent cell for controlled in vitro studies of activation. Retinol resulted in suppressed DNA synthesis in proliferating HSC, a reorganization of actin filaments, and a return of fat storage. However, it did not suppress the expression of fibrogenic genes such as those for collagens type I and IV, and TGF-beta1. Furthermore, retinol-treated cells may increase expression of these genes in response to conditioned medium from hepatocyte cultures. The effect is especially apparent for collagen type I mRNA, and with conditioned medium from iron-loaded hepatocytes. Thus, retinol may be a two-edged sword in iron overload, potentially suppressing HSC proliferation on the one hand, and sensitizing a fibrogenic pattern of gene expression on the other. Factors influencing this balance merit further study. 相似文献
20.