K-ras mutations in 239PuO2 canine lung neoplasms.

Single-strand conformational polymorphism (SSCP) analysis and direct sequencing methods were used to examine lung tumors derived from a cohort of beagle dogs with inhalational exposures to 239PuO2. These exposures were done at Pacific Northwest Laboratories where 18-month-old beagle dogs were given 239PuO2 by single-dose inhalation and allowed to live out their life-spans. Formalin-fixed paraffin-embedded blocks of tissues from 25 dogs exposed to 239PuO2 by aerosol inhalation which later developed lung tumors were available for this study.

Proliferation indices in spontaneous canine lung cancer: proliferating cell nuclear antigen (PCNA), Ki-67 (MIB1) and mitotic counts.

Proliferation indices were measured for specimens from 55 spontaneous canine lung tumours, collected by surgical biopsy from clinical patients and archived in paraffin wax blocks. These indices were then related to the mitotic index and histological type of the tumour. Proliferating cell nuclear antigen (PCNA) and Ki-67 (MIB1) proteins were detected immunohistochemically with a biotin-streptavidin amplified detection system on a representative tissue section from each tumour.

Clostridium difficile: a survey of fecal carriage in cats in a veterinary medical teaching hospital.

Fecal samples collected from 245 cats over a 6-month period were analyzed for the presence of Clostridium difficile. After culture on selective media, isolates were identified by a latex agglutination test, and the presence of toxin A and toxin B gene sequences was determined by polymerase chain reaction. Clostridium difficile was isolated from 23 (9.

Results of chemotherapy for cats with alimentary malignant lymphoma: 21 cases (1993-1997).

Objective: To determine clinical and pathologic findings in cats with alimentary malignant lymphoma and results of treatment with a combination of prednisone, L-asparaginase, vincristine, cyclophosphamide, doxorubicin, and methotrexate.

Design: Retrospective study.

Animals: 21 cats with alimentary malignant lymphoma.

Computer-assisted image analysis of intratumoral vessel density in mammary tumors from dogs.

Objective: To determine whether intratumoral microvessel density can be used to distinguish benign from malignant mammary tumors in dogs and to predict the outcome of surgical treatment for small volume (< 3-cm diameter) tumors.

Sample Population: Tissue sections from 58 mammary tumors (42 malignant and 16 benign) from dogs.

Procedure: Mammary tumors were stained by immunohistochemistry for factor VIII-related antigen.

Evaluation of single-agent mitoxantrone as chemotherapy for relapsing canine lymphoma.

Many chemotherapeutic regimens will induce remission in dogs with lymphoma, but almost all dogs suffer relapse. Mitoxantrone was selected for evaluation as single-agent chemotherapy for relapsing canine lymphoma based on its use in humans undergoing salvage chemotherapy for non-Hodgkin's lymphoma and its tumoricidal effect against canine lymphoma. Dogs entered into study had multicentric lymphoma, and all had been treated solely with a standard combination chemotherapy protocol.

Amelogenin expression in canine oral tissues and lesions.

Amelogenins are major enamel proteins within the enamel extracellular matrix. The expression of amelogenin was confirmed in neonatal tissues of the canine jaw. The sequence of a portion of canine amelogenin cDNA, within exons 5 and 6, was determined and found to be closely homologous to sequences reported in the cow, pig, mouse and human being.

Rapid detection of K-ras gene mutations in canine lung cancer using single-strand conformational polymorphism analysis.

A total of 126 spontaneous lung tumors from pet dogs were examined for K-ras mutations within exon 1 and exon 2 using a non-radioisotope single-strand conformational polymorphism analysis (SSCP) detection method on PCR products. Mutations were confirmed by direct DNA sequencing. Tumors were classified as adenomas (9), bronchioloalveolar carcinomas (59), adenocarcinomas (30), adenosquamous carcinomas (16), squamous cell carcinomas (3) and anaplastic carcinomas (9).

Acute reactions in dogs treated with doxorubicin: increased frequency with the use of a generic formulation.

During a 4-month period, 34 dogs with tumors received a total of 60 doses of a single generic formulation of doxorubicin; 13 acute drug reactions were observed in these 34 dogs, and no acute reactions were observed after replacing the product with the proprietary brand. These reactions were characterized by one or more of the following signs: pruritus; head-shaking; urticaria; erythema of the pinnal, axillary, or inguinal regions; vocalization; vomiting; hyperemic or pale mucous membranes; high heart rate; and high respiratory rate. We propose that a component unique to generic doxorubicin was responsible for the unusually high number of acute drug reactions observed.

Adenosquamous carcinoma arising in a mucinous cystadenoma of the pancreas.

Background: Approximately 500 cystic neoplasms of the pancreas have been reported, and among these the mucinous pancreatic cystadenomas are known to have malignant potential. We report a rare case of a mucinous cystadenoma containing adenosquamous carcinoma.

Methods: We studied the histochemical and immunohistochemical staining characteristics of the tumor by staining with hematoxylin/eosin, Alcian Blue/Periodic Acid Schiff, and with immunoperoxidase-labelled antibodies against carcinoembryonic antigen, epithelial membrane antigen, low and high molecular weight cytokeratins, the proliferation antigen Ki-67, and the tumor suppressor antigen p-53.

Analysis of the equine tumor suppressor gene p53 in the normal horse and in eight cutaneous squamous cell carcinomas.

Wild type equine p53 was amplified between exons 2 and 9 by the polymerase chain reaction using primers designed from conserved regions in other species. An 828 base pair region, corresponding to codons 25-313 of human p53, was sequenced in both directions. Human and equine amino acid sequences were 87% homologous in this region and 96% homologous in conserved domains II-V.

Sequence analysis of canine p53 in the region of exons 3-8.

An 828 base pair region of canine wild-type p53, corresponding to codons 25 through 312 in the human p53 gene, was directly sequenced from asymmetric polymerase chain reaction (PCR) products. The deduced amino acid sequence of the dog was 86%, 73% and 83% homologous to that of the cat, mouse and human proteins, respectively. In the evolutionarily conserved domains II through V, the canine sequence approached 100% homology with the human sequence.

Detection of mammalian and avian hepadnaviruses by the polymerase chain reaction.

The hepadnavirus family contains a number of related viruses able to infect a variety of animal species. In the present study, we have used the polymerase chain reaction and oligonucleotide primers to a conserved region of the viral replicase gene of hepadnaviruses to identify viral sequences in de novo tissues in three well-characterized hepadnavirus systems: the woodchuck, ground squirrel and Pekin duck. We did not detect related hepadnavirus sequences in liver specimens from tree squirrels putatively infected with the tree squirrel hepatitis virus, or in liver specimens from horses with hepatitis (serum sickness), or from dogs with chronic active hepatitis or hepatocellular carcinoma.

K-ras activation in non-small cell lung cancer in the dog.

To investigate the role of K-ras mutations in canine non-small cell lung cancer, we first determined the nucleotide sequence of the normal canine K-ras gene and then examined 21 canine lung tumors for activating K-ras mutations. Canine K-ras was analyzed by direct sequencing of polymerase chain reaction products generated with oligonucleotide primers derived from the human K-ras sequence. Four nucleotide differences were found between the canine and human K-ras sequence from position 5 to 211.

Nucleotide sequence of canine c-N-ras: codons 1 to 71.

The c-N-ras gene has been implicated often in the genesis and/or progression of human leukemias. To our knowledge, the sequence of this gene in the dog has not been reported. Using a system of asymmetric reamplification of double-stranded polymerase chain reaction (PCR) products, we have sequenced normal canine c-N-ras mRNA from position -26 to +213, including codons 12, 13, and 61, which are the sites where oncogenic mutations are most commonly observed.

Mutational analysis of a dominant oncogene (c-Ki-ras-2) and a tumor suppressor gene (p53) in hamster lung tumorigenesis.

In human lung cancers, alterations of both a dominant oncogene (ras) and a tumor suppressor gene (p53) have been identified. Polymerase chain reaction (PCR) analysis of mRNA was used to amplify the c-Ki-ras-2 and p53 genes from Syrian golden hamsters. The PCR products were confirmed by predicted-size analysis, probing with nonradioactive (biotin-labeled) oligonucleotides, and direct sequencing.

Osteogenic sarcoma and cisplatin chemotherapy in dogs: 16 cases (1986-1989).

Sixteen dogs, given adjuvant cisplatin chemotherapy after amputation for osteogenic sarcoma of the appendicular skeleton, had a median survival time of 413 days. Ten dogs (62%) were alive 1 year after amputation. Dogs were given cisplatin at a dosage of 50 mg/m2 of body surface every 4 weeks for a total of 6 cisplatin treatments, or until metastatic disease was detected.

Canine and bovine ras family expression detected and discriminated by use of polymerase chain reaction.

Cellular proto-oncogenes are highly conserved genes thought to be critical in cell growth and differentiation. In this study, we used human sequence designed oligonucleotide primers to detect and discriminate c-Ha-ras-1, c-Ki-ras-2 and c-N-ras genes of dogs and cows by polymerase chain reaction (PCR) amplification of genomic DNA (DNA/PCR). Further, we have applied PCR for analysis of expressed mRNA transcribed from the RAS genes (RNA/PCR).