Biomedical subjects
Publications and source records attributed to M Reifinger.
Mammary carcinomas of six feline patients were subjected to karyotypic analysis. A broad variation in the numerical and structural alterations was evident. None the less, several repeatedly occurring alterations were observed.
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Four mesenchymal neoplasms (two malignant fibroblastic histiocytomas, one fibrosarcoma, one fibroma) were investigated cytogenetically. Although no specific alterations were present, the frequent nonrandom involvement of chromosome E1 became clearly evident. Karyotypic alterations involving unrelated clonal changes were also present in the fibroma.
Twenty feline neoplasms were sequenced in the region from exons 5 to 8 for the presence of tumour suppressor gene p53 mutations. In a spindle cell sarcoma of the bladder, a missense mutation (codon 164 AAG-->GAG, lysine-->glutamic acid) in exon 5 was detected. In a pleomorphic sarcoma, a 23 bp deletion involving the splicing junction between intron 5 and exon 6 was observed. In a fibrosarcoma, a 6 bp deletion of p53 covering 2 bp of exon 7 and 4 bp of intron 7, including the splicing junction, was found. The study demonstrates three new p53 mutations in different types of sarcomas in cats.
A case of basal cell carcinoma in a 10-year-old spaniel dog was analysed cytogenetically. A reciprocal translocation t(10;35) was detectable.
OBJECTIVE: To identify mutations in canine mammary tumors. ANIMALS: 10 tumor-bearing dogs. PROCEDURE: Culture of neoplastic cells originating from mammary tumors was performed, and trypsin-G banding was used for cytogenetic investigations. The same tumors were subjected to molecular genetic screening by use of DNA extraction, polymerase chain reaction, DNA elution, and DNA sequencing for ras oncogenes and the p53 tumor suppressor gene. RESULTS: A broad spectrum of chromosome aberrations was observed, including trisomies, reciprocal translocations, and structural and numerical X-chromosome alterations and deletions. Molecular genetic analysis revealed a tumor suppressor p53 gene mutation in codon 249 of exon 7 in one instance. Interestingly, analyzed mammary tumors were free of mutations in N-ras, K-ras and H-ras, exons 1 and 2. CONCLUSIONS: Chromosome alterations are wide-spread in canine mammary tumors, but no ras family mutations were detected in tumors from these 10 dogs. CLINICAL RELEVANCE: Knowledge about chromosome, oncogene, and tumor suppressor gene damage could be helpful for diagnosis and prognosis of neoplastic diseases in dogs.
Highly conserved regions of the tumour suppressor gene p53, including the typical human tumour hot spots (codons 175, 245, 248, 249, 273 and 282), were investigated in various canine neoplasms. A mutation CGG-->TGG (arginine-->tryptophan) was detected in codon 249 in an adenoma of the circumanal gland.
A heterogeneous population of 100 dogs was examined for age-associated brain involution. The dogs originated from the autopsy material of the institute and were selected irrespective of age, breed and sex. They had no history of neurologic disorders and exhibited no macroscopic cerebral lesions. After decapitation at the atlanto-occipital joint, the head was sawn through the median plane. The brain was removed and the skull reconstructed. The volume of the brain was measured by water displacement; the volume of the cranial cavity was determined by filling up with lead shot and pouring it into a measuring glass. In order to determine cerebral atrophy, the brain volumes were compared with the cranial-cavity volumes. The mean relative brain volume (mean brain volume divided by mean cranial cavity volume) for the 100 dogs was 88.7%. Connected with periods of life, the mean relative brain volumes slightly increased during the first 8 years and slightly decreased during the following years. With regard to the age groups 0-5 years, 5-10 years and more than 10 years, the average relative brain volumes were 88.4, 89.3 and 88.3%. These values did not show statistical significance, i.e. there was no evidence of a decline in brain volume in the ageing dog.
Short term cultures of four feline fibrosarcomas were analysed cytogenetically. There was marked genetic heterogeneity between the four cats, each showing a different clonal abnormality. The aberrations detected were one deleted B2, one marker F1 and two reciprocal translocations, t (A2q; E3q) and t (A1q; B4p).
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Tumour cells in three cases of mammary gland neoplasms in cats were analysed cytogenetically. There was a loss of chromosome B2-material in all the cases, and a loss of chromosome E3-material in two of them.
Four solid tumours (one haemangiopericytoma, one haemangioendothelioma, one spindle-cell sarcoma and one mammary carcinoma) in dogs were analysed cytogenetically. In the haemangiopericytoma, an additional small chromosomal segment was present. Very complex changes including centric fusions and symmetric meta-centrics 1, 6, 10 and 12 were conspicuous in the highly unbalanced karyotype of the haemangioendothelioma. Complex changes, particularly many centric fusions and a tandem translocation 4/14, were features of the spindle-cell sarcoma. One centric fusion and a symmetric metacentric 13 were present in the mammary carcinoma.
An 11-year-old female cat and a 12-year-old male cat developed fibrosarcomas. Trisomy D1 was observed in a high percentage (20%) of the tumour cells of the female patient while a large marker chromosome F1 was present in 25% of the tumour cells of the male patient.
An eight-year-old male cat developed a sarcoma. The cytogenetic evaluation of the tumour cells showed the presence of hyperdiploidy (range 40 to 46 chromosomes). This hyperdiploidy was encountered in all the cells examined. Extra-chromosomes numbers C1, C2, B4, D4 and E3 were mainly responsible for the hyperdiploid chromosomal complements. There was a high incidence of monosomy E3.
Tumor cells of two cases of mammary neoplasms in dog were investigated cytogenetically. An 11-year-old cocker spaniel showed a marked X-chromosome in most metaphases (80%). In a 12-year-old poodle, tumor cells with the following abnormalities were found: trisomy 1, monosomy X and two marker chromosomes.
In a 9-year-old female dog (Basset Artesian Normand) with a mammary adenocarcinoma, cytogenetic evaluation of tumor cells showed a chromosome number of 76 in most metaphases (95%). The following abnormalities were found: symmetric metacentric chromosomes 1 and 6, centric fusion 3/38, a marker X-chromosome (Xmar) and a biarmed small marker chromosome (mar). In the remaining metaphases (5%) there were additional biarmed marker chromosomes present.
An eight-year-old female cat developed a skin neurofibroma. The cytogenetic evaluation of the tumour cells showed the presence of a high percentage (16.4 per cent) of trisomic cells. The trisomy concerned chromosome number D2.
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