PubMed Health⌕ Search

Biomedical subjects

M Rønne

Publications and source records attributed to M Rønne.

At least 19 recordsLinked to original sources
PubMed1996

An extended nomenclature of the canine karyotype.

In contrast to many other animals, knowledge about the canine karyotype is quite sparse. This is due in part to the rather difficult canine karyotypic pattern. Except for the X and the Y chromosome, there are only acrocentric chromosomes, which appear to be quite small and difficult to identify unambiguously. In previous reports, schematic representations of the canine karyotype have been described. However, a nomenclature comparable to that of the human karyotype or the karyotypes of sheep, cattle, or goats does not yet exist for the dog. Based on high-resolution banding of metaphase chromosomes from canine fibroblasts, we propose an ideogram of the canine karyotype with 460 numbered bands and characteristic landmarks. In addition, the centromere positions of the canine chromosomes are determined by a combined GTG-banding/FISH approach, and the R- and G-banding patterns are compared.

Animals↗
PubMed1995

Localization of landmarks and bands in the karotype of Sus scrofa domestica. Comparison between different classifications.

Representative RBG-banded chromosomes of Sus scrofa domestica and diagrammatic representation of the banding patterns at the 600 band stage are presented. Comparison between different classification systems has been performed. It is suggested that the data presented can be applied to gene mapping, localization of chromosome aberrations, comparative cytogenetics, and translation between different classification systems.

Animals↗
PubMed1995

Localization of fragile sites in the karyotype of Felis catus.

High resolution RBG-banding was induced by exposure of cat fibroblast cultures to a folate antagonist and BUdR. After band induction the chromosomes displayed frequent breaks and gaps. To determine whether the observed aberrations were randomly or non-randomly distributed, a total of 300 metaphases were screened for the presence of breaks, gaps, and deletions. Statistical analysis was performed according to Mariani (1989). The 525 band idiogram presented by Rønne et al. (1994) was used for the calculations, and to determine which bands were harbouring an aberration. Bands with seven or more aberrations were considered to harbour a fragile site (Fh7 < 0.01).

Animals↗
PubMed1995

Frequency of sister chromatid exchange and hematological effects in pesticide-exposed greenhouse sprayers.

OBJECTIVES: A cross-sectional study was conducted to investigate whether exposure to pesticides in greenhouses causes hemato- or genotoxic damage in sprayers. METHODS: The frequency of sister chromatid exchange (SCE) in cultured lymphocytes and the number of blood erythrocytes, leucocytes, and thrombocytes were studied among 134 greenhouse sprayers exposed to a complex mixture of almost 50 insecticides, fungicides, and growth regulators and among 157 referents. RESULTS: The hematological profiles did not differ between the exposed and unexposed groups. The SCE frequency was elevated in nonsmoking, but not in currently smoking sprayers when compared with the referents. There was a slight tendency towards an increased SCE frequency with decreasing degree of protection during pesticide applications. The frequency of pesticide applications, lifetime pesticide exposure, and in-season plasma-cholinesterase inhibition (as an estimate of current exposure to organophosphates and carbamates) did not influence the SCE frequency or any of the hematological parameters. CONCLUSIONS: The present results suggest a genotoxic effect from combined subtoxic occupational pesticide exposure, whereas no hematogenic effects could be observed at the current exposure level.

Adult↗
PubMed1992

Myelin deficiency in female rats due to a mutation in the PLP gene.

Myelin deficiency (md) in female rats due to a mutation in the X-linked proteolipid protein (PLP) gene is caused by X-chromosome monosomy. Cytogenetic analysis revealed a single X karyotype [41,X(md/0)]. An immunocytochemical, electron microscopic, and biochemical study was performed on male and female md rats. The central nervous system (CNS) of the female md rat [41,X(md/0)] revealed the same total lack of PLP as the CNS of the affected male littermate [42,XY(md/Y)]. Immunocytochemistry for myelin basic protein (MBP), myelin-associated glycoprotein (MAG), and 2',3'-cyclic nucleotide-3'-phosphodiesterase (CNP) revealed "islands" of myelin sheath-like reaction product in both. Electron microscopy showed great paucity of compact myelin sheaths in 41,X(md/0) and 42,XY(md/Y). Reduced levels of MPB, MAG, and CNP were confirmed for both sexes but MAG and CNP were substantially higher in 41,X(md/0). Sexual differentiation of the brain may account for the observed differences since normal female reproductive organs are present in the md female rat.

Animals↗
PubMed1992

Putative fragile sites in the horse karyotype.

After fluorouracil/5-bromodeoxyuridine synchronization and subsequent FPG-staining, the karyotype of 15 phenotypically normal horses displayed several breaks and gaps. Twelve bands 1q24, 4p12, 8q23, 11p12, 16q21, 17q21, 23q31, 23q32, Xp21, Xq22, Xq25 and Xq27 showed relatively frequent fragility. After thymidine/cytidine synchronization and subsequent GWL-banding the same horses display karyotypes without any fragility. Hence it is suggested that the above listed bands harbour folate and/or 5-bromodeoxyuridine sensitive fragile sites.

Animals↗
PubMed1991

Organotin compounds induce aneuploidy in human peripheral lymphocytes in vitro.

In vitro exposure of PHA-stimulated human lymphocytes to organotin compounds resulted in statistically significant increases in the frequencies of hyperdiploid cells. When taken together with our previous study demonstrating spindle inhibiting effects of the same organotin compounds by an indirect method (Jensen et al., 1989), the present study strongly indicates that organotin compounds are able to induce aneuploidy, probably by affecting spindle function.

Adult↗
PubMed1991

Comparative analysis of autosomes in karyotypes from pig and rabbit using RBG-banding and in situ hybridization.

The chromosomal location of the porcine gene for glucose phosphate isomerase (GPI) was previously mapped to 6p 12----6q21 in the pig karyotype. The replication patterns and morphology of this chromosome are very similar to those of chromosome 14 in the rabbit karyotype. With combined in situ hybridization and RBG-band induction it was demonstrated that the porcine GPI-probe hybridized most frequently to 14p11----14q12 in the rabbit karyotype, indicating a close relationship between morphology, replication pattern and gene location.

Animals↗
PubMed1989

In situ hybridization localizes the human putative oncogene GLI to chromosome subbands 12q13.3-14.1.

Using in situ hybridization, we have localized the human putative oncogene GLI to chromosome subbands 12q13.3-14.1. The precise genomic site is of interest since the region 12q13-15 has been found to be consistently rearranged in neoplasia-associated chromosome abnormalities in lipomas, myxoid liposarcomas, uterine leiomyomas, and pleomorphic adenomas of the salivary gland.

Chromosome Banding↗
PubMed1989

Chromosome preparation and high resolution banding techniques. A review.

High resolution banding techniques enable detection of chromosome rearrangements even within major bands. Banded chromosomes prepared for light microscopic studies of intact metaphase plates are, however, highly modified structures compared with native chromosomes, and the high resolution banding techniques only seem possible because the following methods were standardized and combined. The use of colcemid, which prevents formation of the spindle and thereby collects cells at the metaphase-anaphase border, is routinely used for chromosome preparations. For high resolution banding studies, short exposure time and concentrations near the threshold value have been recommended by several authors. Several agents interfere with chromosome contraction processes, but only a few have had a lasting influence on high resolution banding studies. The most used agents are ethidium bromide, actinomycin D, and Hoechst 33258, which all partially inhibit chromosome contraction. Treatment with hypotonic solutions induces swelling of animal cells, and the methanol in the fixative denatures and precipitates protein by dehydration. The acetic acid coagulates nucleoproteins and causes swelling of the cells. The fixative penetrates the cells rapidly and preserves the chromosome structure. To obtain long segmented chromosomes suitable for high resolution banding hypotonic treatment with .075 M KCl, frequent changes of fixative and overnight fixation at 4 degrees C have been recommended. The use of cell synchronization, 5-bromodeoxyuridine incorporation into DNA, and fluorochrome-photolysis Giemsa (FPG)-staining have improved the quality of high resolution banding. Synchronization techniques, which select for lymphocyte populations in early divisions, provide excellent materials for chromosome preparations and induction of high resolution banding. The banding techniques seem to enhance differences already present in the chromosomes, and the differential Giemsa staining has recently been explained by interactions between the hydrophobic dye complex, the supercoiled DNA helix, and the denaturated histone core of the nucleosomes.

Animals↗
PubMed1988

Ultrastructure of psoriatic epidermis.

The ultrastructure of human affected and unaffected psoriatic epidermis was studied in skin biopsies from 5 patients and 3 normal controls. Transmission electron microscopic investigations revealed abnormalities in all cell layers of the affected epidermis. Common to psoriatic keratinocytes from affected epidermis was the reduction of tonofilaments. The essential ultrastructural changes were located in the stratum granulosum and stratum corneum. Thus, absence of the fusion between the keratohyalin granules and the tonofilaments was found in stratum granulosum. The keratinocytes of the stratum corneum showed a large accumulation of ribosomes and vesicles resembling lipid vesicles.

Actin Cytoskeleton↗