RESUMO
Ultrastructural examination of testicular biopsies from cases of maturation arrest showed that there were characteristic abnormalities of the Sertoli cell junctional connections. These abnormalities together with the meiotic failure afford an explanation for the severe oligospermia or azoospermia noted in patients with maturation arrest. Premature setting up of ectoplasmic specializations in front of early spermatids and/or spermatocytes were also observed.
Assuntos
Oligospermia/patologia , Epitélio Seminífero/patologia , Epitélio Seminífero/ultraestrutura , Espermatogênese/fisiologia , Adulto , Humanos , Junções Intercelulares/patologia , Junções Intercelulares/ultraestrutura , Masculino , Meiose , Células de Sertoli/patologia , Células de Sertoli/ultraestrutura , Espermatócitos/patologia , Espermatócitos/ultraestrutura , Espermatogônias/patologia , Espermatogônias/ultraestruturaRESUMO
The authors report here two new cases of reciprocal translocations in two fertile and hypoprolific boars. Silver stained synaptonemal complexes in surface-spread pachytene nuclei from a boar heterozygous for a reciprocal translocation, and from another one carrying two different reciprocal translocations, were analyzed by electron microscopy. In such heterozygotes, cross-shaped quadrivalent configurations are expected to form in order to allow homologous pairing. In the same boar, the lengths of the fully synapsed arms of the quadrivalent varies from one quadrivalent to the other and heterosynapsis was obvious. Heterosynapsis was also observed with asymmetrical pairing of the non-homologous partners of the quadrivalent. This heterosynapsis is assumed to be a mechanism preventing spermatocyte loss, but inducing a secondary segregational type of impairment of fertility due to foetal wastage leading to reduced prolificacy.
Assuntos
Fertilidade/genética , Triagem de Portadores Genéticos , Complexo Sinaptonêmico/genética , Translocação Genética/genética , Animais , Cariotipagem , Masculino , Meiose/genética , Microscopia Eletrônica , Mitose/genética , Sêmen/citologia , SuínosRESUMO
Pachytene analysis was carried out on an infertile man heterozygous for a pericentric inversion of chromosome 6. The synaptic behavior of the bivalent 6 inversion was analyzed using electron microscopy in silver stained surface microspread of the inversion-bearing spermatocytes. Possible mechanisms of the sterilizing effect caused by the autosomal inversion are discussed.
