Incidence of sex chromosome abnormalities in spermatozoa from patients entering an IVF or ICSI protocol.

OBJECTIVE: The objective of this study was the determination of sex chromosome aneuploidy frequency in spermatozoa from patients included in an in vitro fertilization (IVF) or intra cytoplasmic sperm injection (ICSI) protocol. METHODS: Spermatozoa from nineteen patients, including patients with normal seminal parameters according to World Health Organization (WHO) criteria and patients exhibiting abnormal seminal parameters, were analyzed by dual color fluorescence in situ hybridization (FISH) for aneuploidies of the X and Y chromosomes. Our technique, using only probes for sex chromosomes and not for autosomes, does not discriminate between hyperhaploid and diploid sperm nuclei. The results were analyzed in two different ways: in relation to the semen status, denoted normal or abnormal and with regard to the ability of the sperm to fertilize oocytes when IVF or ICSI was performed. RESULTS: Abnormal semen showed a significant increase in the overall rate of sperm nuclei with XY, XX and YY sex chromosome complements, 1.59% compared to normal semen, 0.78% (p<0.02). Semen shown to be able to fertilize oocytes only by ICSI showed a higher incidence of XY-bearing spermatozoa, 1.26%, compared to semen able to fertilize oocytes by conventional IVF, 0.37% (p<0.001). The incidence of XX-or YY-bearing sperm nuclei was also significantly elevated in the ICSI group (0.25% XX, 0.50% YY) (p<0.02) as compared to the IVF group (0.06% XX, 0.16% YY). CONCLUSIONS: We concluded that infertile men requiring ICSI treatment showed a higher incidence of sex chromosome aneuploidy, due to meiosis I and II nondisjunction, in their spermatozoa as compared to men requiring IVF for reasons of predominantly female infertility.

Athymic rats in preclinical immunodiagnostic studies.

The usefulness of nude rat xenograft systems in immunolocalization studies was investigated using the monoclonal antibody 9.2.27 which binds to melanomas and osteosarcomas. Three human tumors, two melanomas (LOX and FEMX-I) and one osteosarcoma (OHSX), were used. They were established as s.c. xenografts in congenitally athymic (rnu/rnu) nude rats. These serially transplantable tumors showed the same morphology, take rate and growth properties in nude rats as in nude mice. Radiolabeled 9.2.27 F(ab')2 fragments injected i.v. into nude rats were concentrated in s.c. LOX and OHSX xenografts, reaching tumor to blood ratios of up to 30 after 3-4 days. However, the injected antibody failed to concentrate in FEMX-I xenografts, in contrast to previous findings in mice. This discrepancy could be attributed neither to significant differences in in vivo distribution of the labeled antibody nor to the presence of blocking factors in the serum of nude rats. In immunoscintigraphic studies clear images of s.c. LOX tumors were obtained, whereas lung colonies were less well visualized. Biodistribution studies showed a low tumor to blood ratio of about 4 in the latter animals, suggesting a tumor site-dependent variation in homing of labeled antibodies. Radiography was found to be superior to immunoscintigraphy in detecting the lung tumors. The present findings demonstrate that results of immunolocalization studies in nude mice cannot readily be extrapolated to other species. For the purpose of preclinical evaluation of new methods in cancer diagnosis and treatment, tumor xenografts in nude rats may represent a valuable complement to nude mouse models.