Biomedical subjects

O Henegariu

Publications and source records attributed to O Henegariu.

26 records · Page 2Linked to original sources

PubMed1998

Triple-color FISH analysis of 12p amplification in testicular germ-cell tumors using 12p band-specific painting probes.

Forty-nine surgical specimens and nine germ cell tumor lines were analyzed by triple-color FISH using microdissected probes for the cytogenetic bands of chromosome arm 12p (12p11.2, p12, and p13). FISH analysis demonstrated amplification of material from all three bands in all tumors. This amplification was in the form of increased copy number of 12p or i(12p) and/or 12p amplified regions (AMP12p). The number of copies of 12p was variable (4-11 copies) from case to case but tended to remain relatively constant in all clones of the same tumor, even when the amplification took the form of an amplified region composed of 12p material. In tumors with multiple clones, i(12p) and AMP12p were never found in the same cell. No correlation was found between 12p copy number and tumor type. We describe, for the first time, a relative overrepresentation of 12p13 or 12p12-p13 regions in six tumors (two surgical samples and four cell lines), either as "partial 12p" (five cases) or within a 12p amplified region (one case). The ubiquitous amplification of all three 12p bands in germ-cell tumors supports the hypothesis that 12p harbors more than one gene important for oncogenesis of adult male germ-cell tumors, and that these genes may be located in different areas of 12p.

Adult↗

PubMed1997

A case with mosaic di-, tetra-, and octacentric ring Y chromosomes.

A newborn female infant presented with abnormalities of the external genitalia including a 3 x 1 cm phallic structure, a perineal urethral opening, bifid scrotum, and a single urogenital opening. Peripheral blood karyotype was 45,X[81]/46,X,+r(Y)[19], however, there were no signs of Ullrich-Turner syndrome. High resolution G-banding as well as C- and Q-banding did not demonstrate any specific banding pattern or presence of heterochromatin on the ring. However, it was noticed that some of the rings were larger than others. FISH with a probe for Yq12 was negative in all metaphases studied. A Y-specific paint probe hybridized to the entire ring chromosome, confirming its origin. PCR analysis showed the presence of the SRY locus and of proximal Yq locus DYS271. Triple color FISH with probes for the Y centromere, DYZ5 (Yp), and all human telomeres showed the existence of different types of rings, some dicentric, some tetracentric, and some probably octacentric. Owing to the increased risk for gonadoblastoma, a surgical removal of the gonads was performed.

Centromere↗

PubMed1997

PCR and FISH analysis of a ring Y chromosome.

A newborn male infant presented with midshaft hypospadias, chordee, and undescended left testis. Both gonads lacked the tunica albuginea and appeared to be adjacent to structures resembling fallopian tubes. On biopsy, there was marked dysgenesis of both gonads, with a paucity of testicular tubules and foci of ovarian-like stroma. Peripheral blood karyotype was 46,X,mar(Y) [39]/45,X [5]. Right gonadal biopsy material showed the same mosaicism but with a higher proportion of 45,X cells (46%). PCR and FISH analyses with primers/probes from different Yp, Yq, and Ycen loci defined the structure of the marker Y as a probable complex ring with breakpoints in Yq11.21 (very close to the centromere) and in Yp11.32 (the pseudoautosomal region). Based on the phenotype and the laboratory findings, the prognosis given to the patient was for short stature and azoospermia without an increased risk for gonadoblastomas.

Abnormalities, Multiple↗

PubMed1997

Mild "duplication 6q syndrome": a case with partial trisomy (6)(q23.3q25.3).

We report on a female infant with partial 6q trisomy (46,XX,dir dup(6)(q23.3q25.3)) and phenotypic characteristics of the "duplication 6q syndrome," including intrauterine growth retardation, dolichocephaly, depressed nasal bridge, almond-shaped palpebral fissures, short neck, flexion-contractures of the wrists, and mild generalized hypertonia. Although clearly belonging to the described "duplication 6q syndrome," her features were milder than those found in the literature. Comparison of the phenotype of this child with other published reports indicates that specific phenotypic components of the duplication 6q syndrome cannot be attributed to duplication of a specific band or bands on 6q.

Adult↗

PubMed1997

Multiplex PCR: critical parameters and step-by-step protocol.

By simultaneously amplifying more than one locus in the same reaction, multiplex PCR is becoming a rapid and convenient screening assay in both the clinical and the research laboratory. While numerous papers and manuals discuss in detail conditions influencing the quality of PCR in general, relatively little has been published about the important experimental factors and the common difficulties frequently encountered with multiplex PCR. We have examined various conditions of the multiplex PCR, using a large number of primer pairs. Especially important for a successful multiplex PCR assay are the relative concentrations of the primers at the various loci, the concentration of the PCR buffer, the cycling temperatures and the balance between the magnesium chloride and deoxynucleotide concentrations. Based on our experience, we propose a protocol for developing a multiplex PCR assay and suggest ways to overcome commonly encountered problems.

Buffers↗

PubMed1996

Human Y chromosome azoospermia factors (AZF) mapped to different subregions in Yq11.

In a large collaborative screening project, 370 men with idiopathic azoospermia or severe oligozoospermia were analysed for deletions of 76 DNA loci in Yq11. In 12 individuals, we observed de novo microdeletions involving several DNA loci, while an additional patient had an inherited deletion. They were mapped to three different subregions in Yq11. One subregion coincides to the AZF region defined recently in distal Yq11. The second and third subregion were mapped proximal to it, in proximal and middle Yq11, respectively. The different deletions observed were not overlapping but the extension of the deleted Y DNA in each subregion was similar in each patient analysed. In testis tissue sections, disruption of spermatogenesis was shown to be at the same phase when the microdeletion occurred in the same Yq11 subregion but at a different phase when the microdeletion occurred in a different Yq11 subregion. Therefore, we propose the presence of not one but three spermatogenesis loci in Yq11 and that each locus is active during a different phase of male germ cell development. As the most severe phenotype after deletion of each locus is azoospermia, we designated them as: AZFa, AZFb and AZFc. Their probable phase of function in human spermatogenesis and candidate genes involved will be discussed.

Chromosome Mapping↗

PubMed1996

Molecular analysis of the genomic structure of the human Y chromosome in the euchromatic part of its long arm (Yq11).

Conventional methods of long range restriction mapping for analysis of the genomic DNA structure failed in Yq11, because single-copy DNA probes for blot hybridization analyses are rare and the rate of DNA methylation is high in this Y region. Numerous repetitive sequence blocks of unknown extensions are scattered throughout Yq11 and a patchwork of X-Y homologous DNA blocks were found by different investigators. Therefore, our approach towards a molecular analysis of this Y region reduced this complexity by performing first its molecular analysis in YAC clones mapping to Yq11. YACs contain only a part of the whole Yq11 DNA structure. In this paper, we present our first results of this approach based on quantitative blot analysis of 51 DNA loci in 67 YAC clones. The YACs were isolated from the three CEPH libraries and mapped to a contig of 13 Mb from proximal to distal Yq11 with aid of a detailed interval map. In distal Yq11, our analysis revealed the presence of local amplification events of different DNA domains. A model of their possible arrangement is presented.

Chromatin↗

PubMedDate not supplied

Rapid screening of the Y chromosome in idiopathic sterile men, diagnostic for deletions in AZF, a genetic Y factor expressed during spermatogenesis.

A rapid molecular screening programme has been established for the long arm of the human Y chromosome in Yq11 in order to quickly detect small interstitial deletions in this chromosome region. They have been observed in idiopathic sterile males with azoospermia and a severe oligozoospermia and are therefore indicative for deletion of AZF gene sequences. AZF (i.e. azoospermia factor) is a genetic factor located in Yq11 which controls human spermatogenesis. The screening programme is based mainly on a multiplex PCR approach using a series of Y-specific primers amplifying single DNA loci in Yq11. The order of all Y-DNA loci can be unequivocally arranged along the whole long Y arm. Therefore, any detected deletion can be quickly mapped in relation to the proposed position of AZF. Benefits and pitfalls of this new diagnostic Y screening method will be discussed.

Base Sequence↗