Karyotype of teh little blue macaw Cyanopsitta spixii (psittaciformes, aves)

A Ararinha azul (Cyanopsitta) considerada extinta na natureza foi analisada por método citogenético com objetivo de sexagem e estudos evolutivos. A espécie, com 2n = ñ 70 cromossomos, NF = 88, apresentou heteromorfismo de cromossomos sexuais o que permitiu a sexagem de quatro aves mantidas em cativeiro dentro do programa de cooperaçäo com o "Comitê da Arara Spixii

Localization of a mouse centromeric DNA repeat in interphase nuclei.

The position of a mouse DNA repeat located near the centromere of mouse chromosomes X, 11, 13, and 17 was examined in interphase nuclei of bone marrow and fibroblast cells by in situ hybridization of 3H- or biotin-labeled DNA probe 70-38. In most laboratory mouse strains this probe recognizes a single repeat cluster (DXWas70) close to the centromere of the mouse X chromosome. In a few mouse strains, a second locus (D11Was70, D13Was70, or D17Was70, depending on the mouse strain) is located near the centromere of an autosome. In interphase nuclei from mouse strains with the X-linked locus only, two distinct sites of hybridization were found in female mice and one in male mice. These two sites remained separated during the different phases of the cell cycle (G1, early S, late S, and G2) as demonstrated by in situ hybridization of the probe to flow-sorted nuclei. In interphase nuclei from mouse strains with both the X-linked locus and an autosomal locus, four distinct sites of hybridization were found in female mice and three in male mice. Further analysis of loci DXWas70 and D17Was70 showed that these loci were often located in the outer region of nuclei from bone marrow and fibroblast cells.

Automatic detection of fragile X chromosomes using an X centromere probe.

In order to score for the fragile X syndrome, blood samples are prepared with absorption stain labeling by in situ hybridisation of the X chromosome centromeres. Metaphases are located, digitised at high resolution, and segmented fully automatically. A three stage adaptive classification scheme for labeled X chromosomes is then applied. This consists of a simple box classifier to identify plausible X and false positive X chromosomes, followed by a quadratic discriminant classifier that is re-trained for each sample. The modal number of X chromosomes is then determined for each sample and used to refine the classification. A simple fragile site detector is applied to the distal portion of the detected X chromosome long arms. From the results we estimate computer and operator time requirements for a screening system in which the operator reviews only the apparently fragile X chromosomes detected by the computer.

Mosaic sex cromosome contitution in a patient with klinefelter's syndrome who developed metastatic sarcoma of the lung

Foram estudados citogeneticamente o sarcoma dos pulmöes e os sintomas clínicos da síndrome de "Klinefelter's" em um homem branco de 20 anos de idade. Este paciente mostrou linhas múltiplas de células com constituiçäo cromossômica 49,XXYYY, 48,XXYY, 47XXY e 46,XY em sua primeira amostra de sangue. Na segunda amostra recebida um ano depois ele mostrou somente 49,XXYYY e 48,XXYY. Juntamente com este caso estudo, se apresenta uma revisäo da literatura mostrando anomalias constitucionais para certos neoplasmas humanos

Sex determination of blood stains with a recombinant DNA probe: comparison with radioactive and non-radioactive labeling methods.

A recombinant DNA probe hybridizing specifically to human repeat DNA sequence (pHY10) of which about 3000 copies are present on the Y chromosome was used for sex determination of degraded DNA samples of blood stains. Human blood stains of male and female origin were readily differentiated with the pHY10 DNA probe. This radioactive technique enabled reliable and sensitive sex determination from blood or dried blood stains greater than 20 years old. Less than 1 microliter of blood or 1 piece of 0.5 cm length thread of blood stain from cotton fabric was sufficient for the test using dot blot hybridization. Compared with the radioactive labeling method, the photobiotin labeling method showed one thirtieth to one fiftieth lower sensitivity and presented some problems which are expected to be resolvable.

Chromosome banding and DNA replication patterns in bird karyotypes.

The karyotypes of the domestic chicken (Gallus domesticus), Japanese quail (Coturnix coturnix), and griffon vulture (Gyps fulvus) were studied with a variety of banding techniques. The DNA replication patterns of bird chromosomes, analyzed by incorporation of 5-bromodeoxyuridine (BrdU) and deoxythymidine (dT), are presented here for the first time. In particular, the time sequence of replication of the ZZ/ZW sex chromosomes throughout the S-phase was meticulously analyzed. BrdU and dT incorporation are very useful methods to identify homoeologies between karyotypes, as well as rearrangements that occurred in the macroautosomes during speciation. The Z chromosomes of the three birds displayed the same replication patterns, indicating a high degree of evolutionary conservation. In the homogametic male, BrdU and dT incorporation revealed no evidence of asynchronous replication between euchromatic bands in the ZZ pair. The same was true of the three Z chromosomes in a triploid-diploid chimeric chicken embryo. Minor replication asynchronies between the homologous ZZ or ZZZ chromosomes were restricted to heterochromatic C-bands. These results confirm that, in the ZZ male/ZW female sex-determining system of birds, dosage compensation for Z-linked genes does not occur by inactivation of one of the two Z chromosomes in the homogametic male. The heterochromatic W chromosomes of the three species showed bright labeling with distamycin A/mithramycin counterstain-enhanced fluorescence and exhibited significantly delayed DNA replication. The nucleolus organizers of birds, frequently located in microchromosomes, were also distinguished by bright distamycin A/mithramycin fluorescence.

The sex-determining zinc finger sequences in XY females of Akodon azarae (Rodentia, Cricetidae).

Wild populations of Akodon azarae comprise females with a karyotype indistinguishable from that of males. These individuals were formerly assumed to be Xx, the x being an X chromosome with a deletion of most of its long arm. By using a DNA probe derived from the testis-determining region of the human Y chromosome (comprising a candidate gene for the testis-determining factor, Y-linked zinc finger [ZFY]), we demonstrate that A. azarae gonosomally variant females are XY and not Xx. The ZFY sequences in A. azarae are amplified and located in two different families of EcoRI fragments derived from Y-chromosome DNA. No rearrangement or change in the state of methylation of ZFY or ZFX (X-linked zinc finger) sequences were found in XY females. We propose that sex reversal in A. azarae may be mediated by a gene or genes other than ZFX or ZFY.

Distribution of heterozygous translocations and aneuploid spermatocyte frequency in domestic sheep.

In an analysis of the chromosomes in 1556 metaphase II figures from 26 translocation-carrying rams and 84 figures from 3 normal rams (54, XY), there were no hypermodal cells in the normal rams but 35 such cells in the translocation rams, giving mean aneuploid frequencies of 3.92 percent, 4.29 percent, and 5.29 percent for the rams heterozygous for 1, 2, and 3 translocations, respectively. The translocation chromosome in the heterozygous state was found to segregate evenly during meiosis. Although the effect of heterozygosity was to increase the aneuploid frequency of the ram it is seen that the frequency in all translocation-carrying rams is low and it is thought that these cells are eliminated during spermatogenesis and therefore do not reduce the fertility of the sheep.

Lymphocyte responses after cytomegalovirus infection in bone marrow transplant recipients--a one-year follow-up.

A group of 46 bone marrow transplant (BMT) recipients were studied by lymphocyte stimulation with cytomegalovirus (CMV) antigen before, and repeatedly in the first year after, BMT. Of these, 25 patients developed CMV infection and 68% of these got a positive lymphocyte response to CMV. The recipients with an early response (up to 3 months) to CMV antigen after the CMV infection were less prone to develop chronic graft-versus-host disease (GVHD) than those who responded later or not at all (P = 0.002). After the CMV infection, the increased lymphocyte CMV reactivity remained in recipients without chronic GVHD, but recipients with chronic GVHD usually lost their reactivity. The results suggest that it may be possible to predict patients who are not going to develop chronic GVHD by studying lymphocyte responses to CMV infections.

Sex selection by sperm separation and insemination.

The Ericsson albumin filtration technique was used to collect a fraction rich in Y sperm for selective insemination in couples desiring a male infant. Of 35 conceptions in which sex was known at delivery or spontaneous abortion, there were 28 males (80%). Twelve pregnancies were achieved after separation of sperm in a Sephadex gel filtration system designed to allow for collection of a fraction enriched in X sperm. Seven pregnancies have resulted in females, two in males, and one in twins of each sex. One patient aborted, and one is still pregnant. While selection for either sex can be done electively, on the basis of sociologic preference, female selection has, as an additional indication, avoidance of male offspring to carriers of sex-linked diseases.

The determination of sex from forcibly removed hairs.

The determination of sex from forcibly removed hairs in forensic science laboratories has, in the past, been based almost entirely on the presence or absence of the Y chromosome in the cells of the hair root sheath. Since the human male genotype is XY and the female is XX, a technique was devised that permits root sheath cells to be stained sequentially for the Y and then the X chromosome using quinacrine mustard. Following staining, the Y and the X chromosome fluorescence were observed, at pH 5.5 and 3.0, respectively, by epifluorescence. The X and Y chromosome counts obtained for a single hair root specimen were reported as a Y-X (Y minus X) score. The results reported show that specimens from males gave positive Y-X score while specimens from females gave negative Y-X scores. Results of an age study and blind trials were also reported.

XY and XX complete moles: clinical and morphologic correlations.

The results of clinical, morphologic, and histologic analysis of nine XY complete moles (six karyotyped, three Y-chromatin positive) were compared with the results from analysis of 16 XX moles. Five of the nine XY moles were proved to result from dispermy while all the 16 XX moles studied originated from the doubling of a haploid sperm. At follow-up delayed decrease or rebound of urinary (or serum) human chorionic gonadotropin levels was noted in three of eight women with XY moles and in five of 15 women with XX moles. One woman with an XY mole was treated for lung metastasis, but her condition remained stable over a 4-year follow-up period. No appreciable difference was noted in the gross and microscopic findings between the XY and XX moles. On the other hand, differences were noted between younger (12 weeks or less of menstrual age) and older (13 weeks or more) moles. Younger moles had smaller, elliptic or club-shaped villi with numerous secondary villous sprouts, poorly demarcated central cisternae, and frequent mesenchymal capillaries. Older moles had larger, oval or globular villi with sparse villous sprouts, well-developed central cisternae, and less frequent remnants of capillaries. Trophoblastic hyperplasia was more marked in older than in younger moles.

Gonadal tumors in patients with gonadal dysgenesis and sex chromosomal rings and fragments.

Patients with female phenotypes and dysgenetic gonads harboring testicular tissue have a markedly increased risk of developing gonadal tumors. Cytogenetic demonstration of Y chromatin is the currently accepted criterion for performing prophylactic gonadectomies in these women. We studied four patients with dysgenetic gonads containing either testicular tissue or germ cell tumors. All had small sex chromosomal fragments which could not be characterized by conventional cytogenetic studies. Clinical features, DNA replication studies, and immunologic assays of Xga and H-Y antigens failed to correlate consistently with the gonadal histology. We recommend prophylactic gonadectomies and subsequent hormone replacement in all patients with female phenotypes, gonadal dysgenesis, and cytogenetically indeterminate sex chromosomal fragments.

A simple and reliable method of chromosome banding for prenatal cytogenetics using a bromodeoxyuridine pulse.

An extremely simple, fully defined and reliable technique for banding chromosomes in situ is described. The method uses a pulse of bromodeoxyuridine to produce replication pattern banding complete with G- and C-type banding in the same karyotype. This enables immediate resolution of problems otherwise requiring extra subculturing and the application of conventional banding techniques. The value of routine chromosome banding in prenatal cytogenetics using such an economical technique is discussed.

Characterization of donor-derived lymphocytes in chimeric rabbits.

Transfer of adult spleen, lymph node, or bone marrow cells to newborn recipients matched with the donor with respect to the major histocompatibility antigen or antigens, but mismatched with regard to immunoglobulin allotypes results in lasting B cell chimerism. Using such chimeras as donors for secondary recipients, the persistence of B cells from the original donor and the ability of such cells to propagate in the secondary recipient have been demonstrated. In contrast to the effective establishment of donor B cells in primary and secondary recipients, functional T cells of donor origin were not demonstrable among lymphocytes of primary recipients.