1,720,987 research outputs found
Molecular analysis of a Y;1 translocation in an azoospermic male
No full textCytogenetic studies on an azoospermic male revealed a balanced Y;1 translocation: 46,X,t(Y;1)(q12;p34.3). In situ hybridization with the probe St35-239 (DXY64) and with a probe detecting telomeric sequences revealed that only the Y telomere is involved in the translocation. Fluorescence in situ hybridization with a chromosome 1 library on meiotic preparations revealed consistent contact of the painted chromosome 1 with the sex vesicle at pachytene, the most advanced stage of spermatogenesis observed. No deletions were observed after Southern blot analysis with probes p49f (DYS1), 50f2 (DYS7), and 52d (DYF27), which map in interval 6 of the Y chromosome, which includes the azoospermia factor (AZF) gene. The results indicate that the infertility of the translocation carrier could be due to an alteration of the sex vesicle structure or to a disturbance of X-chromosome inactivation as a result of the proximity to the autosomal portion
Interphase cytogenetics of the ICF syndrome
No full textInterphase behaviour of centromeric heterochromatin of chromosomes 1 and 16 has been investigated in lymphocytes and fibroblasts of patients with ICF syndrome and of normal subjects with non-isotopic in situ hybridization, using the satellite II-related probe pHuR 195. We found evidence for interphase somatic pairing in ICF lymphocytes with a frequency higher than that found in normal cells. Lymphocytes of ICF patients showed nuclear protrusions and micronuclei and these nuclear abnormalities consistently involved a hybridization signal. Somatic pairing was also present in fibroblasts, but with frequencies similar in normal and ICF subjects. The fibroblasts do not have the major chromosomal abnormalities found in lymphocytes. The degree of heterochromatin condensation in fibroblasts was lower than that in lymphocytes and we postulate that the more decondensed state of chromocentres in the fibroblasts could be the reason for the absence of the major chromosomal abnormalities
Maternal derivation of inv dup (22) and clinical variation in cat-eye syndrome
No full textCytogenetic analysis in a male child with dismorphies and renal anomalies showed an extra bisatellited chromosome. In situ hybridization and an analysis of cytogenetic polymorphisms revealed that the abnormal chromosome derived from a single maternal chromosome 22
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A novel mechanism for the origin of supernumerary marker chromosomes
No full textA ring chromosome 3 and a 47th chromosome formed by the portions of 3p and 3q distal to the r(3) breakpoints were found in a girl with mental retardation and minor facial anomalies. The supernumerary chromosome 3, rea(3), had a primary constriction inside its 3p portion (3p23) and was consistently stable both in lymphocytes and fibroblasts. In situ hybridization with alphoid probes revealed that the r(3) maintained its wild-type-centromere, whereas the rea(3) showed no alphoid-related signals. This case and a similar one recently reported demonstrate that acentric fragments can acquire a new centromere and become stable, and that supernumerary marker chromosomes can also originate by the junction of the acentric portions distal to the centric region forming a ring. The possibility of such a chromosome segregating will depend on its ability to (re)activate a new centromere
Involvement of 9q22.1-31.3 region in pyloric stenosis
No full textA chromosome 9q22.1 -q3 1.3 direct duplication was found in a 40-year-old patient in a screening program for mentally retarded people. The duplicated region was confirmed by fluorescent in situhybridisation (FISH) showing a double fluorescent signal with 9561410 and 931D9 YACs, mapping respectively to q2 1.33-22.1 and 22.3 I -22.33. YAC 933C.5, mapping more distally in 31.3-32, resulted in a single signal
Two sisters with 45,X karyotype: influence of genomic imprinting on phenotype and cognitive profile
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