[Sporadic cutaneous lymphosarcoma of T-cell origin with involvement of lymph nodes and internal organs in a Holstein cow]. / Sporadische kutane T-Zell-Leukose mit Beteiligung von Lymphknoten und inneren Organen bei einer Holstein-Kuh.

Sporadic lymphosarcomas in adult cattle are rare entities with an unknown etiology. This case report describes the course of the disease in a 3.5-year-old cow of the breed German Holstein, which was presented to the veterinarian due to multifocal nodular skin lesions. Several superficial lymph nodes (Lymphonodi mandibulares, parotidei and mammariae) were enlarged, had a tight-elastic consistency and were freely movable. The histopathological and immunohistochemical examination of skin biopsies showed the presence of multifocal cutaneous T-cell lymphosarcomas consistent with a skin leukosis. Bovine leukemia virus infection was excluded by serological investigation of a milk sample and virological examination of a tissue sample, respectively. Seven weeks after the first clinical examination, the cow deteriorated rapidly and was euthanized. A post mortem examination revealed the presence of neoplastic cells within lymph nodes (all superficial lymph nodes of the carcass and Lymphonodi pulmonales), kidney and lungs as well as a liver rupture. Additionally, an overview of the case reports of sporadic bovine cutaneous lymphosarcomas published during the previous 15 years will be provided. The legal background for a further utilization of affected animals for milk and meat production will be discussed. This case report illustrates that sporadic bovine leukosis represents an important differential diagnosis for viral-, bacterial- and parasitic-induced skin lesions and enlargement of lymph nodes in adult cattle.

Acylation of Galpha(13) is important for its interaction with thrombin receptor, transforming activity and actin stress fiber formation.

Palmitoylation of alpha-subunits in heterotrimeric G proteins has become a research object of growing attention. Following our recent report on the acylation of the mono-palmitoylated Galpha(12) [Ponimaskin et al., FEBS Lett. 429 (1998) 370-374], we report here on the identification of three palmitoylation sites in the second member of the G(12) family, Galpha(13), and on the biological significance of fatty acids on the particular sites. Using mutants of alpha(13) in which the potentially palmitoylated cysteine residues (Cys) were replaced by serine residues, we find that Cys-14, Cys-18 and Cys-37 all serve as palmitoylation sites, and that the mutants lacking fatty acids are functionally defective. The following biological functions of Galpha(13) were found to be inhibited: coupling to the PAR1 thrombin receptor, cell transformation and actin stress fiber formation. Results from established assays for the above functions with a series of mutants, including derivatives of the constitutively active mutant Galpha(13)Q226L, revealed a graded inhibitory response on the above mentioned parameters. As a rule, it appears that palmitoylation of the N-proximal sites (e.g. Cys-14 and Cys-18) contributes more effectively to biological function than of the acylation site located more internally (Cys-37). However, the mutant with Cys-37 replaced by serine is more severely inhibited in stress fiber formation (80%) than in cell transformation (50%), pointing to the possibility of a differential involvement of the three palmitoylation sites in Galpha(13).

Development of a monoclonal antibody for ELISA of CYP1A in primary cultures of rainbow trout Oncorhynchus mykiss hepatocytes.

Induction of cytochrome P4501A CYP1A in cultured cells can be used to determine the induction potencies of xenobiotics or complex environmental samples. This report describes the development of an enzyme linked immunosorbent assay ELISA for measurement of CYP1A expression in primary cultures of rainbow trout Oncorhynchus mykiss hepatocytes. Juvenile rainbow trout were injected with naphthoflavone BNF 25 mg kg-1 body weight to induce the synthesis of CYP1A. The CYP1A isoenzyme was purified, characterized by immunological cross reactivity and N terminal sequencing and used to prepare a monoclonal antibody in Balb C mice. The specificity of the antibody for CYP1A was proved by Western blotting of samples from control and BNF injected fish. Two ELISA methods, a direct and a competitive one, were evaluated, with both methods being of comparable sensitivity. Rainbow trout hepatocytes, maintained as monolayers in serum free, chemically defined medium, were exposed to naphthoflavone, and the induction response was measured both by 7 ethoxyresorufin O deethylase EROD activity and the direct ELISA method. Comparison between EROD activity and immunodetectable CYP1A protein can provide information on the catalytic efficiency of CYP1A.