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A Jauch

Publications and source records attributed to A Jauch.

13 recordsLinked to original sources
PubMed1992

Reconstruction of genomic rearrangements in great apes and gibbons by chromosome painting.

The homology between hylobatid chromosomes and other primates has long remained elusive. We used chromosomal in situ suppression hybridization of all human chromosome-specific DNA libraries to "paint" the chromosomes of primates and establish homologies between the human, great ape (chimpanzee, gorilla, and orangutan), and gibbon karyotypes (Hylobates lar species group, 2n = 44). The hybridization patterns unequivocally demonstrate the high degree of chromosomal homology and synteny of great ape and human chromosomes. Relative to human, no translocations were detected in great apes, except for the well-known fusion-origin of human chromosome 2 and a 5;17 translocation in the gorilla. In contrast, numerous translocations were detected that have led to the massive reorganization of the gibbon karyotype: the 22 autosomal human chromosomes have been divided into 51 elements to compose the 21 gibbon autosomes. Molecular cytogenetics promises to finally allow hylobatids to be integrated into the overall picture of chromosomal evolution in the primates.

Animals↗
PubMed1992

Molecular and classical cytogenetic analyses demonstrate an apomorphic reciprocal chromosomal translocation in Gorilla gorilla.

The existence of an apomorphic reciprocal chromosomal translocation in the gorilla lineage has been asserted or denied by various cytogeneticists. We employed a new molecular cytogenetic strategy (chromosomal in situ suppression hybridization) combined with high-resolution banding, replication sequence analysis, and fluorochrome staining to demonstrate that a reciprocal translocation between ancestral chromosomes homologous to human chromosome 5 and 17 has indeed occurred.

Animals↗
PubMed1992

Homologies in human and Macaca fuscata chromosomes revealed by in situ suppression hybridization with human chromosome specific DNA libraries.

We established chromosomal homologies between all chromosomes of the human karyotype and that of an old world monkey (Macaca fuscata) by chromosomal in situ suppression (CISS) hybridization with human chromosome specific DNA libraries. Except for the human chromosome 2 library and limited cross-hybridization of X and Y chromosome libraries all human DNA libraries hybridized to single GTG-banded macaque chromosomes. Only three macaque chromosomes (2, 7, 13) were each hybridized by two separate human libraries (7 and 21, 14 and 15, 20 and 22 respectively). Thus, an unequivocally high degree of synteny between human and macaque chromosomes has been maintained for more than 20 million years. As previously suggested, both Papionini (macaques, baboons, mandrills and cercocebus monkeys, all of which have nearly identical karyotypes) and humans are chromosomally conservative. The results suggest, that CISS hybridization can be expected to become an indispensable tool in comparative chromosome and gene mapping and will help clarify chromosomal phylogenies with speed and accuracy.

Animals↗
PubMed1992

Somatic mosaicism for a deletion of the dystrophin gene in a carrier of Becker muscular dystrophy.

Duchenne muscular dystrophy (DMD) and the allelic milder form of Becker muscular dystrophy (BMD) are caused by mutations of the dystrophin gene on the short arm of the X chromosome. One third of affected individuals are expected to result from de novo mutations. Genetic counselling of families with sporadic cases is complicated by the potential meiotic origin of the mutation in the mother resulting in germline mosaicism. Here we present direct evidence for combined somatic and germline mosaicism for a deletion of the dystrophin gene, thereby proving the mitotic origin of this deletion and pinpointing a further potential pitfall for genetic counselling. The mother of a BMD son and a BMD carrier daughter, both carrying a deletion of dystrophin cDNA 7 (0.5 kb Hind III fragment) and cDNA 8, was herself clinically healthy and had normal creatine kinase levels. A muscle specimen of the mother showed mild overall pathology as well as focal dystrophin deficiency. In contrast chromosomal in situ suppression (CISS) hybridization of metaphase chromosomes using a cosmid clone of the corresponding cDNA deleted in her son revealed no evidence of somatic mosaicism in their lymphocytes. These results emphasize the value of an approach correlating genetic and immunological data for the definition of a carrier state in BMD or DMD. The possibility of somatic mosaicism should be considered when genetic counselling of a family with a sporadic case of BMD or DMD is performed.

Blotting, Southern↗
PubMed1991

Translocation (8;21) in acute nonlymphocytic leukemia delineated by chromosomal in situ suppression hybridization.

In situ suppression hybridization with recombinant bacteriophage DNA libraries for chromosomes 8 and 21 was performed in two cases of acute nonlymphocytic leukemia, type FAB M2. In both cases, cytogenetic analysis by conventional G-banding revealed t(8;21)(q22;q22). In situ suppression hybridization was able to prove the reciprocal nature of the translocation in both cases by identifying the terminal end of chromosome 21 translocated to the derivative chromosome 8q-.

Chromosome Aberrations↗
PubMed1990

Chromosomal in situ suppression hybridization of human gonosomes and autosomes and its use in clinical cytogenetics.

DNA libraries from sorted human gonosomes were used selectively to stain the X and Y chromosomes in normal and aberrant cultured human cells by chromosomal in situ suppression (CISS-) hybridization. The entire X chromosome was stained in metaphase spreads. Interphase chromosome domains of both the active and inactive X were clearly delineated. CISS-hybridization of the Y chromosome resulted in the specific decoration of the euchromatic part (Ypter-q11), whereas the heterochromatic part (Yq12) remained unlabeled. The stained part of the Y chromosome formed a compact domain in interphase nuclei. This approach was applied to amniotic fluid cells containing a ring chromosome of unknown origin (47,XY: +r). The ring chromosome was not stained by library probes from the gonosomes, thereby suggesting its autosomal origin. The sensitivity of CISS-hybridization was demonstrated by the detection of small translocations and fragments in human lymphocyte metaphase spreads after irradiation with 60Co-gamma-rays. Lymphocyte cultures from two XX-males were investigated by CISS-hybridization with Y-library probes. In both cases, metaphase spreads demonstrated a translocation of Yp-material to the short arm of an X chromosome. The translocated Y-material could also be demonstrated directly in interphase nuclei. CISS-hybridization of autosomes 7 and 13 was used for prenatal diagnosis in a case with a known balanced translocation t(7:13) in the father. The same translocation was observed in amniotic fluid cells from the fetus. Specific staining of the chromosomes involved in such translocations will be particularly important, in the future, in cases that cannot be solved reliably by conventional chromosome banding alone.

Chromosome Aberrations↗
PubMed1990

Distribution of chromosome 18 and X centric heterochromatin in the interphase nucleus of cultured human cells.

In situ hybridization of human chromosome 18 and X-specific alphoid DNA-probes was performed in combination with three dimensional (3D) and two dimensional (2D) image analysis to study the interphase distribution of the centric heterochromatin (18c and Xc) of these chromosomes in cultured human cells. 3D analyses of 18c targets using confocal laser scanning microscopy indicated a nonrandom disposition in 73 amniotic fluid cell nuclei. The shape of these nuclei resembled rather flat cylinders or ellipsoids and targets were preferentially arranged in a domain around the nuclear center, but close to or associated with the nuclear envelope. Within this domain, however, positionings of the two targets occurred independently from each other, i.e., the two targets were observed with similar frequencies at the same (upper or lower) side of the nuclear envelope as those on opposite sides. This result strongly argues against any permanent homologous association of 18c. A 2D analytical approach was used for the rapid evaluation of 18c positions in over 4000 interphase nuclei from normal male and female individuals, as well as individuals with trisomy 18 and Bloom's syndrome. In addition to epithelially derived amniotic fluid cells, investigated cell types included in vitro cultivated fibroblastoid cells established from fetal lung tissue and skin-derived fibroblasts. In agreement with the above 3D observations 18c targets were found significantly closer (P less than 0.01) to the center of the 2D nuclear image (CNI) and to each other in all these cultures compared to a random distribution derived from corresponding ellipsoid or cylinder model nuclei. For comparison, a chromosome X-specific alphoid DNA probe was used to investigate the 2D distribution of chromosome X centric heterochromatin in the same cell types. Two dimensional Xc-Xc and Xc-CNI distances fit a random distribution in diploid normal and Bloom's syndrome nuclei, as well as in nuclei with trisomy X. The different distributions of 18c and Xc targets were confirmed by the simultaneous staining of these targets in different colors within individual nuclei using a double in situ hybridization approach.

Amniotic Fluid↗
PubMed1990

Molecular cytotaxonomy of primates by chromosomal in situ suppression hybridization.

A new strategy for analyzing chromosomal evolution in primates is presented using chromosomal in situ suppression (CISS) hybridization. Biotin-labeled DNA libraries from flow-sorted human chromosomes are hybridized to chromosome preparations of catarrhines, platyrrhines, and prosimians. By this approach rearrangements of chromosomes that occurred during hominoid evolution are visualized directly at the level of DNA sequences, even in primate species with pronounced chromosomal shuffles.

Animals↗
PubMed1990

In vitro toxicity of lomefloxacin in rabbit corneal epithelial cell cultures.

Lomefloxacin (NY-198) is a chemotherapic agent from the new 4-quinolone group, acting on DNA gyrase system. Lomefloxacin (LFLX), as some other new 4-quinolone compounds are antimicrobials of potential use for ophthalmic application. A first approach on the oculotoxicity of LFLX is the main purpose of this study. Four concentrations of LFLX (10, 30, 100 and 300 micrograms/ml) were tested on the first subculture of pigmented rabbit corneal epithelial cells. Cell number, protein contents, neutral red stain and wound healing were evaluated. The results showed that the lower concentrations (10 & 30 micrograms/ml) had no effect while the highest one had a remarkable cytotoxic effect. Pharmacokinetic data show that peak values achieved in the cornea and other ocular structures are lower than 40 micrograms/g (0.3% topical application) and, on another hand, MIC values range from less than or equal to 0.05 to 16 micrograms/ml. So, these "critical" concentrations have no cytotoxic effects according to our results. Then, it is concluded that Lomefloxacin could be a useful drug for topical ophthalmic development.

4-Quinolones↗
PubMed1986

Metallothionein protein variants generated in rat liver as a result of DNA and RNA ethylations by the carcinogen diethylnitrosamine.

Metallothionein (MT) is a protein which contains 20 cysteine residues but no aromatic amino acids. It was tested whether treatment of male rats with the hepatocarcinogen diethylnitrosamine (DENA) could ethylate nucleic acids in such a way that protein variants containing measurable amounts of aromatic amino acid residues could be isolated from the livers of treated animals. To give a low limit of detection, the "wrong" amino acid precursors were administered in radiolabelled form at high levels of activity (7 mCi/kg each of [3H]tyrosine and [3H]phenylalanine). 11 microCi/kg [14C]cysteine was given as an internal marker for MT biosynthesis. 6 h after amino acid administration, metallothionein (MT) was isolated from the liver and extensively purified. After acid hydrolysis and collection of Cys, Tyr, and Phe from an HPLC analysis of the amino acids, the 3H/14C ratio was determined. The carcinogen-treated rats exhibited a significantly higher ratio than the vehicle-treated animals. This type of in vivo assay might find interesting applications in the investigation of nucleic acid alkylations as promutagenic lesions.

Alkylation↗