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Biomedical subjects

B Mayr

Publications and source records attributed to B Mayr.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Trisomy 2 in three cases of canine haemangiopericytoma.

Two female (12 and 14 years old) and one male dog (10 years old) developed haemangiopericytomas. Three copies of chromosome 2 were present in the tumours of all three dogs. Additional alterations were an interstitially deleted chromosome 1, centric fusions 3/34 and 8/15, isochromosome 32 and two unidentified marker chromosomes (M1, M2) in one bitch. In the other bitch, the additional alterations were trisomy 37, centric fusions 8/38 and 30/31, and a derivative chromosome 13 (der13). In the male dog, tandem fusion 2/19 was present in addition to two structurally normal chromosomes 2.

Animals↗
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Preoperative evaluation of bronchogenic carcinoma: value of MR in T- and N-staging.

Seventy consecutive patients with a bronchogenic carcinoma, in whom chest radiographs did not allow a sufficient evaluation of primary tumor localization or extension were examined by MR (1T). All diagnoses were confirmed by operation and histopathologic examination (Stage T1: 6 patients, Stage T2: 36 patients, Stage T3: 19 patients, Stage T4: 9 patients). T-staging was correct in 79% of patients. Significant infiltration of major bronchi, of the pericardium, heart, mediastinal fat and chest wall can be visualized with a reasonable degree of accuracy. N-staging based on lymph-node size was correct in 56%. A correlation between lymph-node size and metastatic involvement was not found. MR is limited by the spatial resolution, by the lack of tissue specificity and by artifacts. MR is a useful diagnostic tool in the evaluation of the primary tumor extension, however, especially in borderline cases histopathologic examination is required. A reliable N-staging is not possible based on lymph-node size measurement.

Adult↗
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Sequence of an exon of the feline p53 gene--mutation in a lymphosarcoma.

Exon 8 of tumour suppressor gene p53 was sequenced in domestic cats and showed remarkable similarity to the human sequence. Only four of the 13 nucleotide differences gave rise to interspecific amino acid differences. In an investigated lymphosarcoma we detected a mutation cgg --> tgg (arginine --> tryptophan) in codon no. 282.

Amino Acid Sequence↗
PubMedDate not supplied

Sequence of an exon of the canine p53 gene--mutation in a papilloma.

Exon 8 of tumour suppressor gene p53 was sequenced in domestic dogs. Ten nucleotide differences were revealed in a comparison with the feline sequence. A mutation ACT-->TCT (threonine-->serine) in codon 284 was detected in a papilloma of the oral mucosa.

Animals↗
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Cytogenetic characterization of a canine haemangiopericytoma.

A 15-year-old dachshund bitch developed a haemangiopericytoma in the perineal region. The cytogenetic evaluation of the tumour cells showed a chromosome number of 74. The following abnormalities were found: an intersitially deleted chromosome no. 1 and centric fusions 5/6, 5/14, 7/15 and 9/17.

Animals↗
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Cytogenetic characterization of a fibroma and three haemangiopericytomas in domestic dogs.

Cytogenetic evaluation of tumour cells taken from an 11-year-old mixed breed birth with a fibroma, showed trisomy 1 (2n = 79) and often the presence of a third copy of chromosome 4. In a 13-year-old mixed breed Boxer bitch with a haemangiopericytoma, trisomy 9 (2n = 79) was present. In contrast, another haemangiopericytoma (in a 15-year-old rough-haired Dachshund bitch) showed a deleted chromosome 1, several centric fusions and trisomy 2. Trisomy 2 and trisomy 29 were detected in a third haemangiopericytoma from an 11-year-old rough-haired Dachshund bitch.

Animals↗
PubMedDate not supplied

Mutations in tumour suppressor gene p53 in two feline fibrosarcomas.

Exons 5-7 of the tumour suppressor gene p53 were investigated in genomic DNA of tumours of domestic cats. In one fibrosarcoma investigated we observed a mutation GAG-->AAG (glutamic acid-->lysine) in codon 180; in another there was a mutation CGG-->TGG (arginine-->tryptophane) in codon 248.

Animals↗
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Sequence of an exon of tumour suppressor p53 gene--a comparative study in domestic animals: mutation in a feline solid mammary carcinoma.

Partial sequence determinations were performed on exon 8 of tumour suppressor gene p53 of cattle, sheep, goat, horse and pig. High sequence homology between these species and other species including dog, cat, chicken and man is demonstrated. A mutation CGG-->TGG (arginine-->tryptophan) was detected in a feline solid carcinoma of the mammary gland.

Animals↗
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Cytogenetic, ras, and p53: studies in cases of canine neoplasms (hemangiopericytoma, mastocytoma, histiocytoma, chloroma).

Four case reports of mesenchymal neoplasms showing chromosomal abnormalities are presented. In a case of hemangiopericytoma trisomy 2 and centric fusion 19;21 were present. In a mastocytoma a deleted chromosome 35 was seen. A homogeneously staining region (HSR) on chromosome 1 was detected in a histiocytoma. Trisomy 5 and monosomy 31 were observed in a case of granulocytic sarcoma (chloroma). The lack of mutations in exons 1 and 2 of oncogenes N-ras, K-ras, and H-ras and exons 5, 6, 7, and 8 of tumor suppressor gene p53 in these four patients and in a larger series of investigated dogs (25 hemangiopericytomas, 12 mastocytomas, and 8 histiocytomas) is highlighted.

Animals↗
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NOR activity, heterochromatin differentiation, and the Robertsonian polymorphism in Sus scrofa L.

The karyotype of the European wild pig (Sus scrofa scrofa L.) was analysed by means of silver-staining and the chromomycin A3/distamycin A/DAPI fluorescent banding technique to locate active NORs and to differentiate types of C-bands. The ribosomal RNA genes are localized at the secondary constrictions of chromosomes 8 and 10. All biarmed chromosomes, with the exception of chromosome 15/17 and the Y, had a chromomycin bright centromeric region that was moderately fluorescent with distamycin A/DAPI (DA/DAPI). Conversely, all acrocentric chromosomes and the Robertsonian fusion product (15/17) exhibited DA/DAPI bright centromeric heterochromatin. The results are compared with the chromosomal staining behavior of the domestic pig (Sus scrofa domestica L.) and discussed with respect to presumptive mechanisms of karyotypic evolution.

Animals↗
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Nucleolus organizer regions in the chromosomes of the llama.

Silver nitrate (Ag-AS) staining was applied to chromosome preparations from the llama (Lama glama). The NORs were detected on the secondary constrictions of the short arms or the stalks of five small acrocentric chromosome pairs.

Animals↗
PubMedDate not supplied

A new type of Robertsonian translocation in the domestic dog.

A cytogenetic analysis of 112 domestic dogs led to the detection of a new Robertsonian translocation (Robertsonian translocation 1/31). This translocation was restricted to the poodle breed; it occurred in high frequency and was encountered in the homozygous and heterozygous state.

Animals↗
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NORs, heterochromatin, and R-bands in three species of Cervidae.

Chromomycin A3 banding of the chromosomes of three species of Cervidae (red deer, fallow deer, roe deer) allows the demonstration of both centromeric constitutive heterochromatin and R-banding patterns useful for identifying all the chromosomes of a given karyotype. In all three species significant amounts of chromomycin-bright heterochromatin are present at the centromeres of all autosomes. The X chromosomes of all investigated species contained appreciable amounts of centromeric heterochromatin. AgNO3 staining was applied sequentially to detect the location of active nucleolus organizer regions (NORs). The distribution of NORs was reasonably conservative in the investigated species.

Animals↗
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Further resolution of the quail karyotype and characterization of microchromosomes by counterstain-enhanced fluorescence.

Sequential staining with a counterstain-contrasted fluorescent R-banding technique (chromomycin A3/distamycin A-DAPI) followed by DAPI-actinomycin D-induced quinacrine-fluorescence-Hoechst 33258 (QFH)-type banding allowed the identification of quail chromosomes up to chromosome 19. The chromomycin A3-positive staining behavior of the W chromosome and of the heterochromatic areas of most microchromosomes indicated their GC-rich nature.

Animals↗
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Characterization of heterochromatin by sequential counterstain-enhanced fluorescence in three domestic bird species: Meleagris gallopavo, Columba livia domestica, and Anser anser L.

The karyotypes of three avian species--Meleagris gallopavo, Anser anser L., and Columba livia domestica--were investigated by means of counterstain-enhanced fluorescence techniques (chromomycin A3/distamycin A/DAPI followed by DAPI/actinomycin D staining). A heterochromatin characterization of macro- and microchromosomes was performed. CMA3-positive (GC-rich) regions in the turkey included the telomeres of chromosomes 1, 3, 4, and Z. In the goose, the chromosome 2 was also CMA3-bright at the telomeres. The W chromosome possessed large amounts of CMA3-bright material on the short arm in both the turkey and the goose. Two types of centromeric heterochromatin were distinguished on acro- to telocentric chromosomes 6 to 14 in the pigeon. The microchromosomal heterochromation of the turkey and goose was GC-rich but had a high degree of variation. In the pigeon, several microchromosomes possessed predominantly AT-rich heterochromatin.

Animals↗