A dicentric iso (Y) chromosome in an infertile male

A dicentric Y chromosome was detected in a 30-year-old azoospermic male patient who was found to be mosaic for 45,X/46,X,dic Y(qter----p11::p11----qter). The dicentric iso (Y) chromosome was identified conclusively with C-banding, G-banding and Q-banding techniques. The relationship of structural abnormalities of the Y chromosome and azoospermia is discussed.     

Ring Y chromosome: 45,X/46,X,r(Y) chromosome mosaicism in a phenotypically normal male with azoospermia

Summary Chromosome analysis of lymphocytes in a phenotypically normal male with azoospermia showed a mosaicism 45,X/46,X,r(Y). Seven other cases from the literature are discussed.     

3-Deazauridine triggers dose-dependent apoptosis in myeloid leukemia cells and enhances retinoic acid-induced granulocytic differentiation of HL-60 cells

Therapeutic nucleoside analogue 3-deazauridine (DU) exerts cytotoxic activity against cancer cells by disruption of DNA synthesis resulting in cell death. The present study evaluates whether DU alone at doses 2.5-15 microM or in combination with all trans retinoic acid (RA) or dibutyryl cAMP (dbcAMP) is effective against myelogenous leukemia. The data of this study indicate that DU induces dose-dependent cell death by apoptosis in myeloid leukemia cell lines HL-60, NB4, HEL and K562 as demonstrated by cell staining or flow cytometry and agarose gel electrophoresis. 24h-treatment with DU produced dose-dependent HL-60 cell growth inhibition and dose-independent S phase arrest that was not reversed upon removal of higher doses of DU (10-15 microM). Exposition to nontoxic dose of DU (2.5 microM) for 24h followed by RA or dbcAMP and 96 h-cotreatment with DU significantly enhanced RA- but not dbcAMP-mediated granulocytic differentiation. Cell maturation was paralleled with an increase in the proportion of cells in G1 or G2+M phase. We conclude that, depending on the dose or the sequence of administration with RA, an inhibitor of DNA replication, DU triggers a process of either differentiation or apoptosis in myeloid leukemia cells.     

A 45,X male with translocation of euchromatic Y chromosome material

Summary A phenotypically normal 32-year-old male with azoospermia was found to have a 45,X karyotype with presence of excess euchromatic material on 14p. The parents' karyotypes are normal. This observation is interpreted as a Y/14 translocation with loss of the heterochromatic Y chromosome material.     

Factors influencing myeloid stem cell (CFU-C) survival after cryopreservation of human marrow and chronic granulocytic leukemia cells

Human marrow stem cells obtained from 20 patients (9 with nonhematological malignancy, 11 with acute leukemia in remission) and peripheral blood stem cells from 27 patients with chronic granulocytic leukemia were cryopreserved in 10% dimethyl sulfoxide (Me₂SO). It was found that the optimal cooling rate for the human myeloid stem cells (CFU-C) ranged from 1 to 3 °C per minute. The myeloid stem cells (CFU-C) maintained their viability for up to one year of storage in liquid nitrogen, after an initial 20% reduction due to the freezing procedure. Myeldoid stem cells survived better when thawed and diluted at room temperature (RT) than at 4 °C. However, the viability of thawed stem cells decreased when stored at RT for more than 1 hr. The viability of stem cells cryopreserved in bags and ampoules was similar. No differences were noted in the surivial of normal human marrow stem cells and cells from patients with chronic granulocytic leukemia when cryopreserved under similar conditions.     

Prognostic significance of chromosome analysis in de novo acute myeloid leukemia (AML)

Between 1981 and 1986 cytogenetic studies of bone marrow and/or blood cells in 139 patients with de novo acute myeloid leukemia (AML) were performed. The overall incidence of chromosomal aberrations was 53%, and this was not significantly influenced by sex, age nor the FAB classification. The aberrations most often found were: complex anomalies (n = 13), t(8; 21) (n = 10), trisomy 8 (n = 9), monosomy 7 (n = 6), monosomy 5, 5q-, trisomy 11, 12p- (n = 4) and trisomy 6, 11q-, inv (n = 3). The prognostic significance of chromosomal findings was evaluated in 112 patients treated by combination chemotherapy. The chromosomal status NN, AN, AA did neither significantly influence complete remission rate (NN: 68%, AN: 71%, AA: 60%) nor mean survival (NN: 24, AN: 26.6, AA: 35.6 months). On the other hand, certain types of chromosomal anomalies were of prognostic value. CR was obtained in all 10 patients with t(8; 21) but only in 2 out of 9 patients with complex aberrations. Median duration of CR in patients with t(8; 21) was significantly longer than in patients with a normal karyotype (30 vs 7 months).     

Enhancing effect of lucanthone (miracil D) on the frequency of X-ray-induced chromosome loss in drosophila male germ cells

The effect of lucanthone (miracil D), an inhibitor of RNA synthesis, plus X-irradiation on Drosophila melanogaster males X^c2yB/Ysc⁸y⁺ and on the subsequent production of chromosome loss via breakage has been investigated. Lucanthone feeding plus 495 R induced a significantly higher frequency of chromosome loss when irradiation was given in three equal fractionated doses at 3-h intervals than the same dose given acutely. On the other hand, the difference in frequency of non-disjunctional females was not significant. The enhancing effects of this chemical were found only in the fractionated series but were absent in acute X-irradiation series. This effect was found primarily in those cells in spermatid and spermatocyte stages at the time of irradiation. A pertinent point of interest presented was that not only protein synthesis but also RNA synthesis may play a significant role in the development of radiation damage and in postradiation repair processes at the chromosomal level, since inhibition of RNA synthesis may eventually inhibit protein synthesis.     

A new deletion of the mouse Y chromosome long arm associated with the loss of Ssty expression, abnormal sperm development and sterility

The mouse Y chromosome carries 10 distinct genes or gene families that have open reading frames suggestive of retained functionality; it has been assumed that many of these function in spermatogenesis. However, we have recently shown that only two Y genes, the testis determinant Sry and the translation initiation factor Eif2s3y, are essential for spermatogenesis to proceed to the round spermatid stage. Thus, any further substantive mouse Y-gene functions in spermatogenesis are likely to be during sperm differentiation. The complex Ssty gene family present on the mouse Y long arm (Yq) has been implicated in sperm development, with partial Yq deletions that reduce Ssty expression resulting in impaired fertilization efficiency. Here we report the identification of a more extensive Yq deletion that abolishes Ssty expression and results in severe sperm defects and sterility. This result establishes that genetic information (Ssty?) essential for normal sperm differentiation and function is present on mouse Yq.     

Primitive progenitor cells in the blood of patients with chronic granulocytic leukemia

We measured the number of blast colony-forming cells (Bl-CFC) in the blood of 11 patients with untreated chronic granulocytic leukemia (CGL). The culture system used detects three types of Bl-CFC (Types I, II and III) in normal marrow, of which Bl-CFC (I) are the most primitive and might represent the putative hemopoietic stem cell. The mean numbers of Bl-CFC (I) in CGL blood, normal bone marrow and normal blood were 134 +/- 29 (+/- SEM), 127 +/- 21 and 1.5 +/- 0 respectively per 1 X 10(6) mononuclear cells. These findings are consistent with the concept that CGL is due to a primary increase in stem cell numbers with secondary increases in committed progenitor and leukocyte numbers.     

A 45,X male with evidence of a translocation of Y euchromatin onto chromosome 15

Summary A 19-year-old male with azoospermia was found to have a 45,X karyotype with additional euchromatic material on 15p. The parents' karyotypes are normal. The cytogenetic data, the positive H-Y-typing, and the presence of Yp-specific restriction fragments detected in the proband's genome by molecular DNA probes suggest that the short arm of the Y chromosome, including part of the centromere, is translocated onto the nucleolus organizer region (NOR) of chromosome 15.     

The sole presence of the testis-determining region of the Y chromosome (SRY) in 46,XX patients is associated with phenotypic variability.

Four cases of XX patients with testis development are reported. The aim of this study was to describe their clinical features and to see if there was any relationship between phenotypes and the presence of Y material. Several human Y-derived sequences including the SRY probe were used to analyze the DNA of the patients. Yp material including the pseudo-autosomal region and SRY was detected. The cases reported in this study confirm that XX true hermaphrodites cannot be distinguished from XX males on the basis of their genotypes. There is no relationship between clinical and anatomical phenotypes and the presence of Y material. SRY does not warrant a complete and normal testis differentiation. Although similar in some features with Klinefelter's syndrome patients, XX males exhibit specific clinical manifestations due to the lack of Y-specific genes.