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Purpose: The study aims to determine whether there is an altered bivalent positioning in metaphase I human spermatocytes from Robertsonian translocation carriers., Methods: Metaphase I human spermatocytes from three 45,XY,der(13;14)(q10;q10) individuals and a 45,XY,der(14;15)(q10;q10) individual were analyzed. Proximity relationships of bivalents were established by analyzing meiotic preparations combining Leishman staining and multiplex-FISH procedures. Poisson regression model was used to determine proximity frequencies between bivalents and to assess associations with chromosome size, gene density, acrocentric morphology, and chromosomes with heterochromatic blocks. The hierarchical cluster Ward method was used to characterize the groups of bivalents with preferred proximities in a cluster analysis. Bivalent groups obtained were individually compared with those obtained in normal karyotype individuals evaluated in a previous study., Results: A total of 1288 bivalents were examined, giving a total of 2289 proximity data. Only four positive significant proximities were detected for each type of Robertsonian translocation. Significant bivalent associations were only observed by small-size chromosomes for MI,22,XY,III(13q14q). These results were clearly divergent from 46,XY individuals. Moreover, cluster analysis revealed that about 30 % of the bivalents showed changes in their proximity relationships in metaphase I., Conclusions: The territorial organization of bivalents in metaphase I human spermatocytes changes in the presence of a Robertsonian translocation.

Objective: To determine whether there is a preferential bivalent distribution pattern in metaphase I human spermatocytes and to analyze whether this positioning is influenced by chiasmata count, chromosome size, gene density, acrocentric morphology, and heterochromatic blocks., Design: Proximity frequencies of bivalents were evaluated with the analysis of meiotic preparations combining sequentially standard techniques and multiplex fluorescence in situ hybridization., Setting: University., Patient(s): Twenty-five men consulting for fertility problems., Intervention(s): Unilateral testicular biopsies., Main Outcome Measure(s): Proximity analyses were performed for each bivalent considering as nearby bivalents those that were part of the first ring around the bivalent studied. Data were analyzed using Poisson regression models, multidimensional scaling, and cluster analysis., Result(s): Some bivalents have a preferential relative position. Significant associations among bivalents related to chromosome size, high gene density, and acrocentric morphology were observed. Chiasmata count and heterochromatic blocks were nonconditioning parameters of the bivalent organization., Conclusion(s): This study demonstrates that distribution in metaphase I is nonrandom and influenced by chromosome size, gene density, and acrocentric chromosome morphology. Results support that some features defining chromosome territories are maintained during meiosis., (Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Structural reorganization carriers usually present compromised fertility accompanied by an increased risk of producing gametes with chromosomal abnormalities that can be transmitted to the offspring. In part these imbalances are ascribed to result from the occurrence of meiotic disturbances produced by the rearrangements in the proper segregation of other chromosome pairs. This phenomenon of interference has been called interchromosomal effect (ICE). Several studies have been performed to assess the occurrence of ICE in structural reorganization carriers by analyzing the frequencies of numerical abnormalities in the gametes. Nevertheless, the occurrence and distribution of these disturbing events still is a controversial issue. In this work we present compiled data from 130 sperm fluorescent in situ hybridization (FISH) studies performed in carriers of the most frequent structural rearrangements in humans: 44 Robertsonian translocations, 66 reciprocal translocations and 13 inversions. Data from 7 complex//multiple rearrangements will be considered in a separate group. Significant increases of gametes with numerical abnormalities have been detected in all types of reorganization carriers. Among the groups of non-complex//multiple rearrangements, Robertsonian translocations appear to be the most prone to produce such interference (54.5%%) closely followed by reciprocal translocations (43.9%%). In contrast, ICE's were only detected in 7.7%% of the inversion carriers analyzed. The presence of complex//multiple rearrangements seems to be an important factor for promoting ICE, as 71.4%% of these carriers presented increased rates of gametes with numerical abnormalities. Altogether, almost half of the structural reorganization carriers (45.4%%) present a higher reproductive risk of producing aneuploid//diploid spermatozoa compared to the general population. This high incidence has been obtained by analyzing a small set of chromosomes, suggesting that underlying meiotic disorders could be present in these individuals. Further ICE studies in structural reorganization carriers will help to clarify the still unknown predisposing cytogenetic features that promote this phenomenon. [ABSTRACT FROM AUTHOR]

Robertsonian translocations are one of the most frequent reorganizations in humans. Their segregational behavior and their implication in the occurrence of interchromosomal effects (ICEs) has been an important topic of research for the past 10 years. Most of the cases analyzed correspond to rearrangements with chromosomes from the D-group (chromosomes 13, 14 and 15), whereas some rare Robertsonian translocations are scarcely found in the literature, mainly those with both chromosomes from the G-group (chromosomes 21 and 22) and those involving chromosomes from both groups (D;G translocations). Results supporting/rejecting the existence of the ICE phenomenon have been reported, showing the need for more studies to characterize its distribution. In this study, sperm fluorescent in situ hybridization studies have been performed in three D;G Robertsonian translocation carriers: two men with the translocation t(14;21) and a third individual with the rare t(13;22) reorganization. Segregation and ICE results have been considered in relation to their cytogenetic features and all previously published data. The compiled information discards a particular segregation behavior related to the chromosomes involved. In contrast with this segregational homogeneity, heterogeneous ICE results were observed, indicating a significant but random distribution of such phenomenon. [ABSTRACT FROM AUTHOR]

Objective: To analyze whether the preferential proximity between acrocentric bivalents and the XY pair described at pachytene was maintained in metaphase I human spermatocytes. Design: Proximity frequencies of autosomic bivalents to the sex bivalent were evaluated with the analysis of meiotic preparations combining sequentially standard techniques and multiplex fluorescence in situ hybridization. Setting: Assisted reproduction centers. Patient(s): Thirty-seven men consulting for fertility problems. Intervention(s): Unilateral testicular biopsies. Main Outcome Measure(s): Proximity frequencies analysis to the XY pair, evaluated individually and grouping bivalents, was carried out using a logistical regression model with repeated measures. Result(s): Bivalents 22 and 15 were observed more frequently near to the sex bivalent than the others. Significant interindividual differences were not observed. Conclusion(s): Results suggest that bivalents distribution to the metaphase plate is nonrandom. The maintenance of the acrocentric chromosomes’ proximity to the sex bivalent from pachytene to metaphase I would indicate that the relative bivalents position would be notably preserved. The observation of non-interindividual variability, despite different infertility etiology, suggests that the nuclear organization pattern remains largely unaffected even if spermatogenesis is compromised. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the reliability and applicability of the spot-counting system (Cytovision Spot AX workstation) which offers an alternative to the tedious manual analysis of sperm fluorescence in situ hybridization (FISH).Design: Manual and automatic analyses were performed and compared.Setting: Universitat Autònoma de Barcelona.Patient(s): Twenty-four men who asked for information on infertility showing different seminal parameters.Intervention(s): A semen sample for each patient was collected and prepared for FISH.Main Outcome Measure(s): A dual-color FISH using specific probes for chromosomes 13 and 21 and a triple-color FISH with centromeric probes for chromosomes 18, X, and Y were used (Vysis). Standard FISH analysis was carried out. Automatic analysis was subsequently performed using a Spot AX system.Result(s): Overall, we performed 120 comparisons. In 116 out of 120 (96.67%), the percentage of anomalies reported using manual counting fell within the incidence detected using the automatic system. In the remaining comparisons, statistical differences were detected (4 out of 120; 3.33%). Time consumed by the automatic analysis was always higher than the manual one, being influenced by the characteristics of the preparations.Conclusion(s): The spot-counting system has potential, but before the service is ready to be offered, we still need to overcome some limitations associated with it. [ABSTRACT FROM AUTHOR]

: ObjectiveTo determine the meiotic behavior of a ring Y chromosome in a semen sample from a 45,X/46,X,r(Y)/46,X,dic r(Y) patient and the possible interchromosomal effects of the ring on other chromosome pairs.: DesignRetrospective analysis.: SettingUniversitat Auto`noma de Barcelona.: PatientAn oligoasthenoteratozoospermic patient who presented for infertility consultation.: Main outcome measure(s)The sex chromosome content of spermatogenic cells, meiotic figures, and spermatozoa in the ejaculate and the possible interchromosomal effects on chromosomes 13, 18, and 21 were analyzed by using multicolor fluorescence in situ hybridization. Germ-cell aneuploidies were scored.: Result(s)X0 cells are meiotically incompetent. All meiotic figures were exclusively XY, and 80% showed unpaired sex chromosomes. A high proportion of postreductional cells were XY (45.5%) or nullisomic for sex chromosomes (13.92%). This percentage decreased in spermatozoa to 14.89% and 27.66%, respectively. A statistically significant increase in X-bearing versus Y-bearing cells both in postreductional cells (23.9% vs. 14.3%) and spermatozoa (41.9% vs. 19.3%) was also observed. Evidence for an interchromosomal effect on chromosome 21 was detected.: Conclusion(s)Data suggest that this patient had a generalized increase incidence of chromosome anomalies, underscoring the importance of incorporating screening for sperm aneuploidies in genetic analysis of affected patients. [Copyright &y& Elsevier]