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21.
Interchromosomal duplications of the adrenoleukodystrophy locus: a phenomenon of pericentromeric plasticity 总被引:13,自引:5,他引:13
Eichler EE; Budarf ML; Rocchi M; Deaven LL; Doggett NA; Baldini A; Nelson DL; Mohrenweiser HW 《Human molecular genetics》1997,6(7):991-1002
A 9.7 kb segment encompassing exons 7-10 of the adrenoleukodystrophy (ALD)
locus of the X chromosome has duplicated to specific locations near the
pericentromeric regions of human chromosomes 2p11,10p11, 16p11 and 22q11.
Comparative sequence analysis reveals 92-96% nucleotide identity,
indicating that the autosomal ALD paralogs arose relatively recently during
the course of higher primate evolution (5-10 million years ago). Analysis
of sequences flanking the duplication region identifies the presence of an
unusual GCTTTTTGC repeat which may be a sequence-specific integration site
for the process of pericentromeric- directed transposition. The breakpoint
sequence and phylogenetic analysis predict a two-step transposition model,
in which a duplication from Xq28 to pericentromeric 2p11 occurred once,
followed by a rapid distribution of a larger duplicon cassette among the
pericentromeric regions. In addition to facilitating more effective
mutation detection among ALD patients, these findings provide further
insight into the molecular basis underlying a pericentromeric-directed
mechanism for non- homologous interchromosomal exchange.
相似文献
22.
DL?MagerEmail author AD?Haffajee PM?Devlin CM?Norris MR?Posner JM?Goodson 《Journal of translational medicine》2005,3(1):27
Background
The purpose of the present investigation was to determine if the salivary counts of 40 common oral bacteria in subjects with an oral squamous cell carcinoma (OSCC) lesion would differ from those found in cancer-free (OSCC-free) controls. 相似文献23.
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25.
A case of a cystic metastasis of squamous cell carcinoma of palatine tonsil in a 54-year-old male is reported, clinically presenting as a branchiogenic cyst. The grade of differentiation of the squamous cell epithelium lining the cyst was very variable: in some areas it was extremely well differentiated, thus resembling common benign branchial cleft cyst; transition to dysplastic areas with features of carcinoma in situ was visible and finally, in one small focus, invasion of the epithelial structures into the lymphoid tissue was observed. Despite its metastatic nature, the tumor fulfilled histological criteria of a so called malignant branchiogenic cyst (branchiogenic carcinoma). The authors discuss the existence of primary malignant branchiogenic cyst and the criteria necessary for its diagnosis. 相似文献
26.
Postnatal mice lacking neurotrophin-3 (NT3) are deficient in Merkel cells of touch domes and whisker follicles. We examined the mechanism of Merkel cell loss by immunocytochemistry and electron microscopy. Merkel cell of whisker follicles of NT3 null newborns exhibited decreased immunoreactivity for cytokeratin 8 and contained apoptotic bodies that were positive for cleaved caspase-3, a marker of active apoptosis. By electron microscopy, the Merkel cells displayed aggregation of chromatin along the nuclear membrane, with the marginated chromatin forming caps at the periphery of the nucleus. Ribosomes aggregated in the cytoplasm, while dense core granules characteristic of Merkel cells were still discernible. Finally, the Merkel cells and their nuclei fragmented into apoptotic bodies. None of the apoptotic Merkel cells were contacted by nerve fibers, and their desmosomal contacts with surrounding keratinocytes disappeared. After postnatal day 6 apoptotic Merkel cells were no longer observed, and the number of surviving Merkel cells was severely reduced. They were flat and contained few osmiophilic granules. We conclude that perinatal apoptosis is responsible for the loss of Merkel cells lacking innervation in NT3 null mice. 相似文献
27.
Robert Sabovcik Pavel Kucera Blaise Prod'hom 《Pflügers Archiv : European journal of physiology》1996,431(4):599-607
The presence of a Ca2+-blockable monovalent cation current is demonstrated in isolated ectodermal cells of the chick embryo using the whole-cell patch-clamp method. In the absence of any stimulation, the whole-cell current is time independent and rectifies outwardly at membrane potentials higher than +40 mV The outward current is neither carried by Cl– channels nor by K+ channels. Application of a Ca2+-free solution containing 1 mmol/l ethylenediaminetetraacetic acid (EDTA) elicits a large inward current and increases the outward current. The inward current can be carried by extracellular Li+, Na+, K+ and Cs+, but notN-methyl-d-glucamine. The Ca2+-blockable monovalent cation channel discriminates very poorly among these cations. The estimated number of channels per cell is around 2000. Extracellular protons block the inward Na+ current in the absence of extracellular Ca2+. The apparent negative logarithm of the dissociation constant for proton (pK
H) at –100 mV is 5.8. Among 12 potential channel modulators, including verapamil and nifedipine, only quinine decreases the current. Quinine blocks this current with a dissociation constant,K
d, equal to 0.18 mmol/l, independent of the membrane potential. This study demonstrates the presence of a whole-cell Ca2+-blockade monovalent cation current in dissociated chick ectodermal cells with permeation properties similar to those observed at the single-channel level. Contrary to studies made of other tissues, we did not observe any blocking effect of verapamil and nifedipine on the Ca2+-blockable monovalent cation current. 相似文献
28.
0 引言 我科 1996 / 1998分别应用消痔灵与强的松龙混合液、消痔灵液、强的松龙液行鼻息肉内 ,鼻息肉蒂部注射治疗鼻息肉各 5 0例 ,并设对照组为鼻腔滴入及口服类固醇激素 5 0例 ,合计 2 0 0例 ,观察并对比其疗效 .1 对象和方法1.1 对象 男 12 8例 ,女 72例 ,年龄 8~ 78(平均 38)岁 ,病程 32 a~ 45 (平均 4.5 ) a.其中在本次治疗前做过一次鼻息肉摘除术后复发的 2 7例 ,做过 2次或 2次以上手术的 12例 .主要症状为鼻塞、流脓涕、头痛及嗅觉减退 .全部病例治疗前均行鼻窦 X线拍片 ,其中上颌窦炎 12 5例、筛窦炎 5 8例、蝶窦炎 2例、… 相似文献
29.
30.
Associations between both genetic and environmental biomarkers and lung cancer: evidence of a greater risk of lung cancer in women smokers 总被引:3,自引:4,他引:3
Tang DL; Rundle A; Warburton D; Santella RM; Tsai WY; Chiamprasert S; Hsu YZ; Perera FP 《Carcinogenesis》1998,19(11):1949-1953
This molecular epidemiologic case-control study of lung cancer incorporated
three complementary biomarkers: the glutathione S- transferase M1 (GSTM1)
null genotype, a potential marker of susceptibility, and polycyclic
aromatic hydrocarbon-DNA adducts (PAH- DNA) and sister chromatid exchanges
(SCE), both indicators of environmentally induced genetic damage.
Associations between biomarkers and lung cancer were investigated, as were
possible gene-environment interactions between the GSTM1 null genotype and
tobacco smoke exposure. Subjects included 136 primary non-small cell lung
cancer surgical patients and 115 controls at the Columbia Presbyterian
Medical Center. Questionnaire and Tumor Registry data, pre-treatment blood
samples and biomarker measurements on blood were obtained. Overall, GSTM1
null genotype was significantly associated with lung cancer [odds ratio
(OR) = 2.04, 95% confidence interval (CI) = 1.13-3.68]. ORs for GSTM1 and
lung cancer were significant in females (2.50, 1.09-5.72) and smokers
(2.25, 1.11-4.54) and not significant in males (1.4, 0.58-3.38) and
non-smokers (0.88, 0.18-4.33). However, ORs for males versus females and
smokers versus non-smokers did not differ significantly. The OR for GSTM1
and lung cancer in female smokers was 3.03 (1.09- 8.40), compared with 1.42
(0.53-4.06) in male smokers. In contrast to PAH-DNA adducts in leukocytes,
SCE did not differ between cases and controls. Neither biomarker differed
significantly between the two GSTM1 genotypes. The combined effect of
elevated PAH-DNA adducts and GSTM1 genotype on case-control status (16.19,
1.2-115) appeared multiplicative. Results suggest that the effect of the
GSTM1 null genotype is greatest in female smokers, which is consistent with
other evidence that indicates that women are at higher risk of lung cancer
than males, given equal smoking. Persons with both the GSTM1 deletion and
elevated PAH-DNA adducts may represent a sensitive subpopulation with
respect to carcinogens in tobacco smoke and other environmental media.
相似文献