Polymorphism of heavy-chain genes in immunoglobulins of wild mice

The serums of 123 wild mice from six different geographic locations in the United States contain five of the six known heavy-chain antigenic determinants that have been identified in immunoglobulin of inbred laboratory strains of mice. On the basis of the distribution of determinants in inbred strains,44 of the mice were judged to be heterozygotes of various combinations and two had combinations of determinants that were unusual and could only have occurred in laboratory inbred mice by recombination.     

2-chain immunoglobulin A molecules: abnormal or normal intermediates in synthesis

Immunoglobulin A (gammaA) myeloma proteins secreted by plasma-cell tumors of mice are of two types, a common four-chain molecule and a rare two-chain (3.9S) molecule. The close similarity between two-chain gammaA molecules and four-chain gammaA molecules and their polymers is demonstrated in tryptic peptide maps of isolated polypeptide chains and by precipitin reactions with rabbit antiserums to gammaA immzunoglobulins. However, a difference between these two types is distinguishable with homologous antiserums. Homologous antiserums to two-chain gammaA immunoglobulins are specific and do not cross-react with four-chain gammaA immutnoglobulins.     

Mycoplasma bovis and otitis in dairy calves in the United Kingdom

Signs of severe otitis media in 20% of dairy calves on one farm were associated with Mycoplasma bovis infection, based on isolation from the external ear canal and nares. Affected calves seroconverted to M. bovis and no other significant bacteria were isolated. Infection was considered likely to have originated from cows in the milking herd based on evidence of seroconversion and detection of infection in a milk sample. M. bovis infection should be considered when investigating otitis problems in calves.     

Canine bile duct carcinoma

Twenty-four adenocarcinomas of the hepatobiliary system were found among 110 primary hepatic neoplasms: 22 of these were intrahepatic, one involved the extrahepatic bile duct and one the gall bladder. Histologically, 10 intrahepatic neoplasms were classified as cholangiocarcinoma, and 12 as bile duct cystadenocarcinoma. The former were characterized by tubular structures lined by anaplastic cuboidal or columnar cells with diffuse fibrous stroma, and the latter by multiple cystic structures with papillary and solid areas. Half the bile duct cystadenocarcinomas showed benign cysts and transition to adenocarcinomas. This was seen in only one case of cholangiocarcinoma. The extrahepatic bile duct carcinoma was characterized by tubular structures lined with flattened cuboidal cells with scant stroma. The gall bladder adenocarcinoma contained many acinar structures lined with columnar or cuboidal cells and separated by thin stroma. Distant metastasis was found in 87.5% (21 of 24) sites of metastasis.     

Feline anaplastic giant cell adenocarcinoma of the thyroid

An 8-year-old castrated, male, domestic short-haired cat had anaplastic giant cell adenocarcinoma in the thyroid gland. The cat had difficulty in breathing and swallowing because of a rapidly growing mass in the left thyroid region that partially enclosed the trachea and esophagus and had evidence of diffuse discrete interstitial pulmonary metastases. The neoplasm, which was locally invasive, was formed by groups of pleomorphic cells arranged in an endocrine-like pattern. The cells were found, spindle, fusiform or irregular; some were large and multinucleated with up to 50 nuclei. Metastases were in the lungs, pleura and regional lymph nodes. Microscopically, both thyroid glands were involved; areas of transition from a well differentiated papillary adenocarcinoma to an anaplastic form were seen.