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991.
Sun F Kozak G Scott S Trpkov K Ko E Mikhaail-Philips M Bestor TH Moens P Martin RH 《Human reproduction (Oxford, England)》2004,19(8):1770-1773
Infertile men have an increased frequency of aneuploid sperm. We have determined that decreased recombination is associated with the production of aneuploid sperm in humans. The aim of this study was to determine whether some cases of infertility are associated with decreased meiotic recombination. Analysis of the early stages of meiosis was performed in a 33-year-old man with non-obstructive azoospermia. Newly developed immunocytogenetic techniques were used to identify the synaptonemal complex (SC) in various stages of prophase. Antibodies to meiotic proteins identified the SC (SYN1/SCP3), the centromere (CREST) and recombination sites (MLH1). Only 36 meiotic spreads were recovered from the infertile man, compared with hundreds available from controls. One-third of the cells were in zygotene compared with 4% in controls, demonstrating an inability of bivalents to synapse and progress to pachytene. The infertile man had a greatly reduced frequency of recombination, with a mean of only 32.7 MLH1 foci/cell (range 1-60) compared with 46.0 (range 21-62) in control donors. A high proportion of cells (73%) contained at least one autosomal bivalent with zero MLH1 foci, compared with only 4.5% in control donors. Discontinuities in the SC were also more prevalent (68% of cells versus 26% in controls). This is the first demonstration of dramatic pachytene-stage abnormalities in an infertile man using these powerful new immunocytogenetic techniques. 相似文献
992.
Xavier Sastre‐Garau Jrme Couturier Josette Derr Alain Aurias Jerzy Klijanienko Ral Lagac 《The Journal of pathology》2002,196(1):97-102
Inflammatory myofibroblastic tumours (IMTs) were initially considered to be benign reactive processes, but cases with an unfavourable outcome have been reported. Moreover, clonal genetic alterations have recently been published in some cases, suggesting that IMT may represent a malignant neoplastic entity. This paper reports a case of IMT that developed in the mammary gland, an unusual site. The histological picture was characterized by a proliferation of spindle cells with little cellular atypia and rare mitoses, associated with a polymorphous inflammatory infiltrate. Their immunophenotype, characterized by the expression of vimentin, smooth muscle actin, and cytokeratins, corresponded to that of myofibroblasts. Cytogenetic analysis revealed the clonal nature of the lesion. The modal karyotype was 48, X, ins(2;X)(q34;p21.2p22.2), +7, del(9)(p23), +19. Including the present observation, a 9p deletion has now been found in three cases of IMT. These observations show that IMT may be a clonal neoplasm, even in sites different from deep soft tissues. 相似文献
993.
Extraskeletal myxoid chondrosarcoma: multimodal diagnosis and identification of a new cytogenetic subgroup characterized by t(9;17)(q22;q11) 总被引:2,自引:0,他引:2
Bjerkehagen B Dietrich C Reed W Micci F Saeter G Berner A Nesland JM Heim S 《Virchows Archiv : an international journal of pathology》1999,435(5):524-530
Extraskeletal myxoid chondrosarcoma is a rare malignant soft tissue tumour that can be difficult to diagnose correctly, especially
preoperatively. We describe four cases of extraskeletal myxoid chondrosarcoma of the extremities diagnosed by a multimodal
approach. The cytological examination of fine-needle aspirates showed small and round, mildly pleomorphic cells lying in sheets
and cords, but also dispersed within a myxoid and metachromatic intercellular substance. Histological, electron microscopic
and immunocytochemical examination also yielded findings compatible with the diagnosis of extraskeletal myxoid chondrosarcoma.
Cytogenetic analysis demonstrated a t(9;22)(q22;q12) in two tumours and a t(9;17)(q22;q11) in the third and fourth. The translocation
t(9;22)(q22;q12) has been described repeatedly in extraskeletal myxoid chondrosarcoma but never in other tumours; hence, the
detection of this pathognomonic chromosome abnormality in short-term cultured cells from fine-needle aspirates verified the
diagnosis in two of the cases. The t(9;17)(q22;q11) found in the last two cases probably represents a new cytogenetic subgroup
of extraskeletal myxoid chondrosarcoma as it, too, is unknown in other contexts. The multimodal approach taken in these four
cases enabled a definite diagnosis of a rare malignant tumour whose cytological and histological features alone are usually
not sufficiently distinct to rule out other differential diagnostic possibilities.
Received: 16 March 1999 / Accepted: 1 June 1999 相似文献
994.
P. Valdés J. Bosch R. Grave J. Hernandez J. Riera R. Pascual R. Biscay 《Brain topography》1992,4(4):309-319
The structure of the normal resting EEG crosspectrum SVV(omega) is analyzed using complex multivariate statistics. Exploratory data analysis with Principal Component Analysis (PCA) is followed by hypothesis testing and computer simulations related to possible neural generators. The SVV(omega) of 211 normal individuals (ages 5 to 97) may be decomposed into two types of processes: the xi process with spatial isotropicity reflecting diffuse, correlated cortical generators with radial symmetry, and processes that seem to be generated by more spatially concentrated, correlated sources. The latter are reflected as spectral peaks such as the process. The eigenvectors of the xi process are the Spherical Harmonic Functions which explains the recurring pattern of maps characteristic of the spatial PCA of qEEG data. A new method for estimating sources in the frequency domain which fits dipoles to the whole crosspectrum is applied to explain the characteristics of the localized sources. 相似文献
995.
Effect of unilateral somatosensory stimulation prior to sleep on the sleep EEG in humans 总被引:3,自引:3,他引:3
SUMMARY The hypothesis that local activation of brain regions during wakefulness affects the EEG recorded from these regions during sleep was tested by applying vibratory stimuli to one hand prior to sleep. Eight subjects slept in the laboratory for five consecutive nights. During a 6-h period prior to night 3, either the left or the right hand was vibrated intermittently (20 min on-8 min off), while prior to night 5 the same treatment was applied to the contralateral hand. The sleep EEG was recorded from frontal, central, parietal and occipital derivations and subjected to spectral analysis. The interhemispheric asymmetry index (IAI) was calculated for spectral power in nonREM sleep in the frequency range 0.25-25.0 Hz for 0.5-Hz or 1-Hz bins. In the first hour of sleep following right-hand stimulation, the IAI of the central derivation was increased relative to baseline, which corresponds to a shift of power towards the left hemisphere. This effect was most prominent in the delta range, was limited to the first hour of sleep and was restricted to the central derivation situated over the somatosensory cortex. No significant changes were observed following left-hand stimulation. Although the effect was small, it is consistent with the hypothesis that the activation of specific neuronal populations during wakefulness may have repercussions on their electrical activity pattern during subsequent sleep. 相似文献
996.
中国东北汉族一个先天性白内障家系致病基因的鉴定 总被引:5,自引:0,他引:5
目的鉴定一个先天性白内障家系的致病基因。方法根据已知与先天性白内障有关的12个致病基因的染色体上的定位,分别选取3~4个的微卫星标记位点,对该家系进行连锁分析。通过测序鉴定致病基因。结果在1q21.1GJA8位点显示最大Lod值2.44。致病基因定位于1q21.1区的GJA8基因,构成缝隙连接的缝隙连接蛋白Connexin50。DNA序列分析鉴定显示其第2外显子的第191个碱基杂合突变T>G导致其蛋白产物第64位缬氨酸转变为甘氨酸。结论Connexin50的V64G新生突变是导致该家系的致病原因。 相似文献
997.
The DQA gene of the rabbit major histocompatibility complex (MHC, RLA) is highly polymorphic and, in contrast to those reported for other mammalian species, is present as a single copy. These properties allow use of this gene in a method to type the class II locus of RLA by a combination of single-stranded conformational polymorphism (SSCP) and heteroduplex (HD) analysis. Familial segregation of RLA-DQA was shown and RLA class II types for rabbits of unknown pedigree were determined using migration patterns of amplified genomic DNA. Typing results were confirmed in experiments where unknown samples were mixed with products from rabbits of RLA types defined by sequence analysis. These analyses detected an RLA-DQA allele in addition to the five previously described; this new allele is designated RLA-DQA-F. 相似文献
998.
Hironobu Tawaraya Showgo Ohkoshi Kenji Kuwana Masashi Watanabe Tomoteru Kamimura And Hitoshi Asakura 《Journal of medical virology》1995,45(4):367-372
Mass screening for hepatitis C virus antibody was carried out in 875 inhabitants (313 men and 562 women) of a town in Japan with a high rate of hepatitis B virus infection. The overall rate of positivity for anti-HCV was 8.8% (6.4% in men and 10,1% in women). The rate of positivity for hepatitis B virus surface antigen was 11.2%. Five subjects (0.6%) were positive for both markers. HCV-RNA was detected in 65 (88.4%) of 77 individuals who were positive for anti-HCV and in 1 (1.5%) of 60 individuals negative for anti-HCV. The genotype of the HCV genome was determined by PCR analysis using type-specific primers in 60 individuals. HCV type 1b was detected in 51 subjects (85%), type 2a in 3 subjects (5%), and type 2b in 6 subjects (10%). None of the individuals was infected with more than one genotype. The nucleotide sequences of the partial nonstructural 5 region of HCV type 1b genotype obtained from 6 individuals showed at least 92.0% homology in the nucleotide sequence, and 94.8% homology in the amino acid sequence. Homology among these clones was greater than their homology with previously described type 1 b sequences. The findings suggest that there was a specific local origin of HCV infection, although it was not possible to identify any single source of HCV infection. The results also indicate the presence of asymptomatic HCV carriers. © 1995 Wiley-Liss, Inc. 相似文献
999.
Agnès Conjard Heidemarie Peuker D. Pette 《Pflügers Archiv : European journal of physiology》1998,436(6):962-969
Energy-rich phosphates, [ATP]/[ADPfree] ratios, and the myosin heavy chain (MHC) complement were determined in single fibres from normal rabbit muscles, and in
fibres isolated from tibialis anterior muscle undergoing fast-to-slow conversion by chronic low-frequency stimulation (CLFS).
In normal muscles, energy-rich phosphate contents and [ATP]/[ADPfree] ratios could thus be assigned to different MHC-based fibre types. Phosphocreatine (PCr) contents and [ATP]/[ADPfree] ratios differed markedly between fast- and slow-twitch fibres, as well as within the fast fibre subtypes. Both magnitudes
were approximately twofold higher in the fastest (type IIB) fibres as compared to the slowest (type I) fibres. According to
PCr contents and [ATP]/[ADPfree] ratios pure and hybrid fibres were aligned in an order similar to that determined by their contractile properties and myofibrillar
ATPase activities. CLFS for up to 30 days induced pronounced decreases in PCr and [ATP]/[ADPfree] which attained levels twofold lower than in normal slow-twitch fibres. In both normal and stimulated muscles, PCr and [ATP]/[ADPfree] ratios were correlated, indicating their equilibrium in the different fibre types. The relationship detected between MHC
isoform expression and the [ATP]/[ADPfree] ratio suggests that the drastic and persistent depression of the cellular energy state may act as an important signal initiating
fast-to-slow transformation processes in muscle fibres.
Received: 26 June 1998 / Accepted: 31 July 1998 相似文献
1000.
采用位于α3′HVR同侧与成人型多囊肾病基因(PKD1)更加接近的pGGG1及另一侧的24-1和218EP6等探针对正常人基因组DNA进行限制性片段长度多态性(RELP)分析,分别检测各等位片段的频率,在此基础上,应用这三个基因探针与3′HVR一起对2个成人型多囊肾病家系成员进行单体型分析,在这2个家系中,5个APKD患者的RFLP单体型被证明与PKD1基因相连锁,发现一个重组体,并检测出二个症状前个体。 相似文献