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G Stetten

Publications and source records attributed to G Stetten.

At least 55 records · Page 3Linked to original sources
PubMed1992

The role of the sex-determining region of the Y chromosome (SRY) in the etiology of 46,XX true hermaphroditism.

The syndrome of 46,XX true hermaphroditism is a clinical condition in which both ovarian and testicular tissue are found in one individual. Both Mullerian and Wolffian structures are usually present, and external genitalia are often ambiguous. Two alternative mechanisms have been proposed to explain the development of testicular tissue in these subjects: (1) translocation of chromosomal material encoding the testicular determination factor (TDF) from the Y to the X chromosome or to an autosome, or (2) an autosomal dominant mutation that permits testicular determination in the absence of TDF. We have investigated five subjects with 46,XX true hermaphroditism. Four individuals had a normal 46,XX karyotype; one subject (307) had an apparent terminal deletion of the short arm of one X chromosome. Genomic DNA was isolated from these individuals and subjected to Southern blot analysis. Only subject 307 had Y chromosomal sequences that included the pseudoautosomal boundary, SRY (sex-determining region of Y), ZFY (Y gene encoding a zinc finger protein), and DXYS5 (an anonymous locus on the distal short arm of Y) but lacked sequences for DYZ5 (proximal short arm of Y) and for the long arm probes DYZ1 and DYZ2. The genomic DNA of the other four subjects lacked detectable Y chromosomal sequences when assayed either by Southern blotting or after polymerase chain reaction amplification. Our data demonstrate that 46,XX true hermaphroditism is a genetically heterogeneous condition, some subjects having TDF sequences but most not. The 46,XX subjects without SRY may have a mutation of an autosomal gene that permits testicular determination in the absence of TDF.

Base Sequence↗
PubMed1992

Mechanisms of ring chromosome formation in 11 cases of human ring chromosome 21.

We studied the mechanism of ring chromosome 21 (r(21)) formation in 13 patients (11 unique r(21)s), consisting of 7 from five families with familial r(21) and 6 with de novo r(21). The copy number of chromosome 21 sequences in the rings of these patients was determined by quantitative dosage analyses for 13 loci on 21q. Nine of 11 r(21)s, including the 5 familial r(21)s, showed no evidence for duplication of 21q sequences but did show molecular evidence of partial deletion of 21q. These data were consistent with the breakage and reunion of short- and long-arm regions to form the r(21), resulting in deletion of varying amounts of 21q22.1 to 21qter. The data from one individual who had a Down syndrome phenotype were consistent with asymmetric breakage and reunion of 21q sequences from an intermediate isochromosome or Robertsonian translocation chromosome as reported by Wong et al. Another patient, who also exhibited Down syndrome, showed evidence of a third mechanism of ring formation. The likely initial event was breakage and reunion of the short and long arms, resulting in a small r(21), followed by a sister-chromatid exchange resulting in a double-sized and symmetrically dicentric r(21). The phenotype of patients correlated well with the extent of deletion or duplication of chromosome 21 sequences. These data demonstrate three mechanisms of r(21) formation and show that the phenotype of r(21) patients varies with the extent of chromosome 21 monosomy or trisomy.

Alleles↗
PubMed1992

Fetal ascitic fluid: a new source of lymphocytes for rapid chromosomal analysis.

BACKGROUND: The cells found in ascites can be processed like amniotic fluid for fetal karyotyping. We have characterized these cells and used them for a rapid cytogenetic result. CASES: Three patients presented with massive fetal ascites detected by sonography. Samples of ascitic fluid were obtained at fetal paracentesis. Cells from the fluid were cultured using standard methods for fetal blood, and were compared with fetal blood lymphocytes and amniocytes. The length of time in culture, chromosome morphology, and mitotic index of ascitic fluid cells were equivalent to those of fetal blood. In the third case, we performed immunophenotyping on the ascitic fluid cells. CONCLUSION: Ascitic fluid contains lymphocytes that permit rapid chromosomal analysis within 96 hours.

Adult↗
PubMed1992

Analysis of reciprocal translocations by chromosome painting: applications and limitations of the technique.

Fluorescent in situ hybridization with chromosome-specific DNA libraries (chromosome painting) is an important new method for assessing chromosome rearrangements. In the research presented in this paper, two familial reciprocal translocations have been studied in the balanced and unbalanced forms, using both traditional G-banding techniques and chromosome painting. Although for each case two chromosomes were involved in the rearrangement, we found that only one chromosome library was suitable for detecting the translocation. These findings illustrate both the potential and the limitations of chromosome painting as a diagnostic tool in cytogenetics.

Adult↗
PubMed1992

Isolated fetal ascites detected by sonography: an unusual presentation of Turner syndrome.

The prenatal sonographic diagnosis of Turner syndrome usually depends upon the discovery of a cystic hygroma or nonimmune hydrops fetalis. This report describes isolated fetal ascites as a newly recognized presentation of the disorder. Intrapartum fetal paracentesis permitted atraumatic vaginal birth. The etiology of the ascites in this case was congenital intestinal lymphangiectasia, consistent with the generalized lymphatic hypoplasia previously described in Turner syndrome.

Adult↗
PubMed1991

Partial trisomies in two spontaneously arising long-lived human keratinocyte lines.

During experiments concerning the introduction of oncogenes into normal human keratinocytes, we observed long-lived colonies arising spontaneously at the same low frequency in control cultures as in those transfected with Ha-rasEJ or activated c-myc or both. Two of these were karyotyped early in their life span and showed additional chromosomal material on the short arm of chromosome 9 in one case and of chromosome 18 in the other, whereas the parental cells had a normal karyotype. This indicates the presence of a partial trisomy in each line, although the origin of the extra chromosomal material is not known. A similarly long-lived human keratinocyte line containing an isochromosome of the long arm of chromosome 8 has been described elsewhere. Together these results suggest that the spontaneous occurrence of long-lived lines is more common in human keratinocytes than in fibroblasts and that a triple dose of one or more genes may be the initial event in this process.

Adult↗
PubMed1991

Origin of chromosome rearrangements in two long-lived human keratinocyte lines.

We have determined the origin of the extra chromosomal material in the karyotypes of two spontaneously-occurring long-lived human keratinocyte lines, HKC-N2 and HKC-N6. In each case the extra material was derived from the chromosome on which it was located. Possible relationships between the triplication of chromosomal material and the overcoming of cell senescence are discussed.

Cell Line↗
PubMed1991

A cystic fibrosis bronchial epithelial cell line: immortalization by adeno-12-SV40 infection.

An immortalized cell line was created from a primary culture of bronchial epithelia isolated from a patient with cystic fibrosis. The culture was transformed with a hybrid virus, adeno-12-SV40, which has been used successfully on a number of different human epithelial tissues. The transformed bronchial epithelial cells have the following characteristics. (1) Cyclic adenosine monophosphate (cAMP) is stimulated by beta-adrenergic agonists. (2) Outwardly rectifying Cl- channels are present on the apical cell membrane. These channels can be activated by depolarizing voltages but not by protein kinase A or C. (3) Keratin is present by immunofluorescence, and this is consistent with the epithelial origin of the cells. (4) The SV40 large T antigen is present as demonstrated by immunofluorescence. (5) Multiple karyotype analyses show modal chromosome number to be 80 to 90. There are an average of four chromosome 7 per cell. (6) The phenylalanine508 deletion in the gene coding for the cystic fibrosis transmembrane regulator is present on at least one chromosome. The cells can be grown in multiple passages, contain the abnormal regulation of the secretory Cl- channel, and should be an appropriate substrate for studies of the mutant cystic fibrosis transmembrane regulatory protein and its interaction with the Cl- channel.

Antigens, Viral, Tumor↗
PubMed1990

Sexual discordance in monozygotic twins.

We report on monozygotic (MZ) twins who were discordant for phenotypic sex and Ullrich-Turner syndrome (UTS). The nonviable female was hydropic with cystic hygromas, ventricular septal defect, bicuspid aortic valve, polysplenia, intestinal malrotation, and small ovaries. The male was phenotypically normal. The monochorionic, diamniotic placenta had hydropic changes limited to the UTS infant's side. Skin samples from the infants and blood from their parents were obtained for cytogenetic and molecular analysis. Karyotypes of the twins were 45,X and 46,XY. Quinacrine polymorphisms on 7 chromosomes and RFLP analysis at 8 loci showed complete identity. MZ twins discordant for phenotypic sex have been described previously. Most of these show evidence of mosaicism in a 45,X patient with a normal 46,XY cell line, and a normal 46,XY male. While the issue of mosaicism in our case cannot be fully resolved, no mosaicism was found in 50 cells analyzed cytogenetically from each culture or by PCR analysis of a Y-specific sequence. The twins probably originated from either postzygotic nondisjunction or anaphase lag, followed or accompanied by twinning. The discordant placental morphology suggests an embryonic origin of at least part of the placental mesenchymal core.

Abnormalities, Multiple↗
PubMed1990

The significance of trisomy 7 mosaicism in chorionic villus cultures.

Two cases of mosaic trisomy 7 confined to the cultured cells and not found in direct preparation were detected from 200 consecutive first-trimester chorionic villus samples (CVS) analysed. The mosaicism was similar in the two cases, but the pregnancy outcome was different. In both cases, the direct metaphases from the CVS were 46,XY. Culture metaphases were mos46,XY/47,XY, +7; the trisomy 7 was seen in 34 per cent of cells from case 1 and 53 per cent from case 2. A sonogram at 15 1/2 weeks revealed fetal death in utero in case 1, and the patient declined amniocentesis. The fetal tissue failed to grow in culture, but the placental cultured cells were 47,XY, +7 in 28 (100 per cent) cells analysed. In the second case, all the amniotic fluid cells were 46,XY and the pregnancy resulted in a normal male with a 46,XY karyotype in the cord blood and foreskin fibroblast cultures. The term placenta was mosaic with 13/163 (8 per cent) trisomy 7 cells. Extensive cytogenetic studies on the placenta for the first time confirmed trisomy 7 mosaicism confined to the villus cultures.

Adult↗
PubMed1990

Evidence for involvement of a Robertsonian translocation 13 chromosome in formation of a ring chromosome 13.

We have used molecular and cytogenetic methods to study the derivation of a ring chromosome 13 in the fetus of a woman mosaic for a translocation chromosome 13. DNA analysis showed that the translocation chromosome was a Robertsonian translocation, not an isochromosome. We suggest that the ring is derived from the translocation chromosome by breaks in both long arms and subsequent reunion, r(13) (q12q14).

Abnormalities, Multiple↗
PubMed1989

Visualization of centromere proteins CENP-B and CENP-C on a stable dicentric chromosome in cytological spreads.

We have screened for the presence of two centromere autoantigens, CENP-B (80 kDa) and CENP-C (140 kDa) at the inactive centromere of a naturally occurring stable dicentric chromosome using specific antibodies that do not cross-react with any other chromosomal proteins. In order to discriminate between the active and inactive centromeres on this chromosome we have developed a modification of the standard methanol/acetic acid fixation procedure that allows us to obtain high-quality cytological spreads that retain antigenicity with the anti-centromere antibodies. We have noted three differences in the immunostaining patterns with specific anti-CENP-B and CENP-C antibodies. (1) The amount of detectable CENP-B varies from chromosome to chromosome. The amount of CENP-C appears to be more or less the same on all chromosomes. (2) CENP-B is present at both active and inactive centromeres of stable dicentric autosomes. CENP-C is not detectable at the inactive centromeres. (3) While immunofluorescence with anti-CENP-C antibodies typically gives two discrete spots, staining with anti-CENP-B often appears as a single bright bar connecting both sister centromeres. This suggests that while CENP-C may be confined to the outer centromere in the kinetochore region, CENP-B may be distributed throughout the entire centromere. Our data suggest that CENP-C is likely to be a component of some invariant chromosomal substructure, such as the kinetochore. CENP-B may be involved in some other aspect of centromere function, such as chromosome movement or DNA packaging.

Autoantigens↗
PubMed1989

Molecular genetic approach to the characterization of the "Down syndrome region" of chromosome 21.

The cytogenetically defined "Down syndrome region" of chromosome 21 has been characterized by DNA analysis in patients with partial trisomy 21 with or without Down syndrome features. Single-copy DNA sequences mapped on chromosome 21 were used to determine copy number by polymorphism and/or dosage analysis in the patients. Given our results, which in some patients were in disagreement with their cytogenetic descriptions, trisomy for locus D21S13 through locus D21S58 is excluded from significant contribution to many Down syndrome features. The minimal chromosome region necessary in triplicate to result in the Down syndrome phenotypes in the patients characterized includes the area from locus D21S55 to locus COL6A1. We could not analyze the region between loci D21S58 and D21S55 and between COL6A1 and 21qter at the molecular level due to a lack of DNA probes and, consequently, the contribution of these areas to a Down syndrome phenotype when present in three copies is unknown. The molecular cloning and mapping of chromosome 21 and the expansion of the patient population studied will likely result in a more precise molecular definition of the Down syndrome region.

Blotting, Southern↗
PubMed1989

Molecular mechanism in the formation of a human ring chromosome 21.

We have characterized the structural rearrangements of a chromosome 21 that led to the de novo formation of a human ring chromosome 21 [r(21)]. Molecular cloning and chromosomal localization of the DNA regions flanking the ring junction provide evidence for a long arm to long arm fusion in formation of the r(21). In addition, the centromere and proximal long arm region of a maternal chromosome 21 are duplicated in the r(21). Therefore, the mechanism in formation of the r(21) was complex involving two sequential chromosomal rearrangements. (i) Duplication of the centromere and long arm of one maternal chromosome 21 occurred forming a rearranged intermediate. (ii) Chromosomal breaks in both the proximal and telomeric long arm regions on opposite arms of this rearranged chromosome occurred with subsequent reunion producing the r(21).

Amnion↗
PubMed1988

Fragile site in chromosome 12 in a patient with two miscarriages.

A heritable fragile site at 12q13 is described in lymphocytes from a woman with a history of multiple miscarriage. The fragile site was not typically folate-sensitive, being expressed in standard medium. The presence of this fragile site may have led to meiotic chromosome breakage and consequent infertility.

Abortion, Habitual↗
PubMed1988

The human Jurkat (FHCRC-11) cell line is heterogeneous in ploidy and cell size and releases detergent-soluble DNA.

Jurkat (FHCRC-11) cells, a human lymphoblastic leukemic line, were characterized as being hypotetraploid with a characteristic deletion in the short arm of chromosome 2 from the terminus to band 24. Although Jurkat cells were size heterogeneous, variability in ploidy was not correlated with density and size differences observed when cells were fractionated by means of gradient centrifugation using Nycodenz as the supporting medium. Also no difference was seen in the chromosome distribution of cells cultured from different portions of the gradient. During cell division Jurkat cells incorporated [3H]thymidine ([3H]TdR) into newly made DNA, including a small percentage that was released into the soluble fraction upon detergent lysis. Small light cells from the top portion of the gradient were more efficient on a per cell basis in incorporating [3H]TdR into DNA from both the detergent-soluble and detergent-insoluble fractions. However, due to the hypotetraploid nature of these cells a definitive assignment to a specific stage in the cell cycle was not possible.

Cell Cycle↗
PubMed1988

Fetal anomalies associated with an inversion duplication 13 chromosome.

We report the cytogenetics and pathology of a fetus with holoprosencephaly associated with an inversion duplication 13 chromosome. The pathology is compared with that found in cases of partial duplication (trisomy) and deficiency (monosomy) of chromosome 13 described in the literature. To our knowledge, this is the first time holoprosencephaly has been associated with this particular inversion duplication 13 chromosome. Careful pathology and complete chromosomal studies proved useful in counseling this couple.

Abnormalities, Multiple↗