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In this retrospective review we assessed the frequency with which atypical glandular cells in cervical smears predict cervical glandular lesions. Asymptomatic patients ( n =34) with one or more smears showing atypical glandular cells and subsequent histopathological assessment were studied. Independent cytological and histological review was undertaken. Cytological review confirmed atypical glandular cells in 29 cases, 17 of which had coexisting squamous dyskaryosis. Histological review of these 29 cases revealed glandular neoplasia in 13 (45%) and microglandular hyperplasia (MEH) in an additional four (14%). Initial reporting had underestimated the prevalence of glandular neoplasia.  相似文献   

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Reverse breeding: a novel breeding approach based on engineered meiosis   总被引:2,自引:0,他引:2  
Reverse breeding (RB) is a novel plant breeding technique designed to directly produce parental lines for any heterozygous plant, one of the most sought after goals in plant breeding. RB generates perfectly complementing homozygous parental lines through engineered meiosis. The method is based on reducing genetic recombination in the selected heterozygote by eliminating meiotic crossing over. Male or female spores obtained from such plants contain combinations of non-recombinant parental chromosomes which can be cultured in vitro to generate homozygous doubled haploid plants (DHs). From these DHs, complementary parents can be selected and used to reconstitute the heterozygote in perpetuity . Since the fixation of unknown heterozygous genotypes is impossible in traditional plant breeding, RB could fundamentally change future plant breeding. In this review, we discuss various other applications of RB, including breeding per chromosome.  相似文献   

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OBJECTIVE: We evaluated the efficacy of fine needle aspiration cytology (FNAC) of the thyroid in a series of 5469 lesions with histological control and studied the causes of, and the possibility of reducing the limitations of the method. METHODS: FNAC was always performed by a pathologist under the guidance of a clinician, using a 22-gauge needle. Generally two aspirations were carried out, and usually four slides were obtained for each nodule; they were then stained with May-Grünwald-Giemsa and with Papanicolaou. The cytological diagnoses were classified in four groups: inadequate, benign, suspicious and malignant. RESULTS: We obtained a complete sensitivity of 93.4%, a positive predictive value of malignancy of 98.6%, and a specificity of 74.9%. At histological control, the cytological diagnosis of Hurthle cell neoplasm corresponded to a significantly higher incidence of malignant neoplasms than the diagnosis of non-Hurthle cell follicular neoplasm (32.1% versus 15.5%). There were 66 false-negative findings, the main cause of diagnostic error (24 cases) being failure to recognize the follicular variant of papillary carcinoma. The number of inadequate FNACs was low (4.2%). CONCLUSION: Our study confirmed the great efficacy of thyroid FNAC. A cytological diagnosis of Hurthle cell neoplasm should be considered an indicator of high risk. Awareness that failure to recognize the follicular variant of papillary carcinoma was the main problem in the interpretation of thyroid FNAC should lead to a decrease of false-negative diagnoses. The inadequate rate was very low, as it was the pathologist personally who performed the needle aspiration.  相似文献   

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二倍体和四倍体栽培苦荞的细胞学比较研究   总被引:4,自引:0,他引:4  
吴云江  陈庆富 《广西植物》2001,21(4):344-346,382
观察和统计了二倍体和四倍体苦荞 (Fagopyrum tataricum)花粉母细胞减数分裂过程 TI、T 时期的异常程度及花粉粒败育性等多个指标 ,并比较分析了二倍体和四倍体苦荞在这些指标上的差异显著性。结果显示 :四倍体苦荞的异常 TI细胞频率、异常 T 细胞频率、TI细胞平均微核数、T 细胞平均微核数及花粉败育率均显著高于二倍体苦荞 ,这表明四倍体苦荞的遗传稳定性和花粉可育性都比二倍体苦荞差。  相似文献   

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Zakharyevich K  Tang S  Ma Y  Hunter N 《Cell》2012,149(2):334-347
At the final step of homologous recombination, Holliday junction-containing joint molecules (JMs) are resolved to form crossover or noncrossover products. The enzymes responsible for JM resolution in?vivo remain uncertain, but three distinct endonucleases capable of resolving JMs in?vitro have been identified: Mus81-Mms4(EME1), Slx1-Slx4(BTBD12), and Yen1(GEN1). Using physical monitoring of recombination during budding yeast meiosis, we show that all three endonucleases are capable of promoting JM resolution in?vivo. However, in mms4 slx4 yen1 triple mutants, JM resolution and crossing over occur efficiently. Paradoxically, crossing over in this background is strongly dependent on the Blooms helicase ortholog Sgs1, a component of a well-characterized anticrossover activity. Sgs1-dependent crossing over, but not JM resolution per se, also requires XPG family nuclease Exo1 and the MutLγ complex Mlh1-Mlh3. Thus, Sgs1, Exo1, and MutLγ together define a previously undescribed meiotic JM resolution pathway that produces the majority of crossovers in budding yeast and, by inference, in mammals.  相似文献   

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In Vitro Cellular & Developmental Biology - Plant - This study investigated developmental changes in cold stressed microspores of Indica rice variety At 303. After 3 d at 10°C,...  相似文献   

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In this retrospective review we assessed the frequency with which atypical glandular cells in cervical smears predict cervical glandular lesions. Asymptomatic patients (n=34) with one or more smears showing atypical glandular cells and subsequent histopathological assessment were studied. Independent cytological and histological review was undertaken. Cytological review confirmed atypical glandular cells in 29 cases, 17 of which had coexisting squamous dyskaryosis. Histological review of these 29 cases revealed glandular neoplasia in 13 (45%) and microglandular hyperplasia (MEH) in an additional four (14%). Initial reporting had underestimated the prevalence of glandular neoplasia.  相似文献   

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We investigated the frequency and types of Y-chromosome microdeletions and chromosomal anomalies in non-obstructive azoospermic and severely oligozoospermic infertile males in northeastern China. The sample consisted of 519 infertile males (456 azoospermic, 63 severely oligozoospermic). PCR assays for Y-chromosome microdeletions and chromosome analysis were performed on all patients and controls. Array-comparative genomic hybridization was performed for three patients with chromosomal anomalies. Fifty-nine of 519 patients (11.37%) had Y-chromosome microdeletions. Microdeletions were found in 11.18% (51/456) of the non-obstructive azoospermic patients and in 12.7% (8/63) of the severely oligozoospermic patients. Eleven of 51 non-obstructive azoospermic patients with Y-chromosome microdeletions had multiple segmental deletions in the AZFb+c regions; four of these patients had chromosomal anomalies. Our sample from northeastern China had a higher frequency of microdeletions among severely oligozoospermic than among non-obstructive azoospermic males.  相似文献   

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Summary An examination of the correlation between RNA and protein synthesis occurring during meiosis and cytological development was made in Trillium erectum microsporocytes. Various reagents known to act at various steps of protein biosynthesis were administered to cultured buds at different developmental stages with more or less effect depending on the stage rather than the reagent.Syntheses were found to be necessary for continued development of the microsporocytes during early prophase. Synthesis during meiotic prophase was also necessary for the maintainance of the condensed state of the late prophase chromosomes, the initial separation of the paired homologous chromosomes, and the orderly function of the spindle. Cytokinesis was readily disturbed at all treatment times. Pairing of homologous chromosomes was not affected and the prespecification of pairing is believed to occur at or near the time of DNA synthesis.The results indicate that the syntheses occurring during meiosis can be correlated with cytological developmental processes.Based on a thesis presented in partial fulfillment of the requirements for the Ph. D. degree at the University of Illinois, Department of Botany.  相似文献   

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Cytological aspects of hemiclonal (meroclonal) inheritance in diploid and triploid males of the hybridogenetic frog Rana esculenta (Rana ridibunda x Rana lessonae) have been studied by DNA flow cytometry. The fact that the R. ridibunda genome contains 16% more DNA than the R. lessonae genome provides the ability to discern cells containing genomes of any species from the water-frog complex under study. Data are presented showing that elimination of the R. ridibunda genome occurs in hybridogenetic males from certain populations. In triploid males, the cytogenetic mechanism of hemiclonal inheritance is simpler than in diploids: after the elimination of a genome (always the genome in the minority in the triploid set; "homogenizing elimination"), no compensatory duplication of the remaining genetic material is necessary, as it is in diploids. The process of elimination can be visualized in triploid males by using DNA flow cytometry to identify cells in the special phase of the spermatogonial cell cycle that we termed the E phase.  相似文献   

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A simple cytological scoring system was evaluated as a method of predicting histological grade and disease-free survival in 79 patients with primary breast cancer. the mitotic activity index and oestrogen receptor status were also assessed for their predictive value. the concordance between cytological scores and histological grades was good (80%) for low-grade lesions, but poor (45%) for high-grade lesions. Similar results were found using the mitotic activity index as a prognostic indicator. Cytological grading was not found to be an independent prognostic indicator after a median follow up of 8 years.  相似文献   

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Among 45 266 women in the Cardiff Cervical Cytology Survey the peak prevalence of suspicious or positive smears was 11.2/1000 at age 45-50 years and of dyskaryosis 10.2/1000 at age 25-29. A suspicious or positive cytological picture at prevalence testing was associated with occult or clinical invasion in 24% of cases, and only 4% of patients with suspicious or positive smears were normal histologically. When dyskaryosis was detected in the prevalence test 20% had carcinoma in situ or microinvasion and 3% had occult or clinically invasive carcinoma. One hundred and twenty-nine (51%) women with dyskaryotic smears did not have a biopsy initially (that is, within two years of the prevalence test), but they were followed up at regular intervals. Subsequently 15 of the 129 gave smears consistently dyskaryotic or worse cytologically and were subjected to biopsy. Of these, two showed dysplasia, 12 carcinoma in situ, and one clinically invasive carcinoma. These findings emphasise the need for repeat cytological or histological examination in any woman with evidence of dyskaryosis in a cervical smear.  相似文献   

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