Central nervous system lymphoma in 18 dogs (2001 to 2015).

OBJECTIVES: To investigate the outcome of dogs with central nervous system lymphoma. MATERIALS AND METHODS: A multi-center, retrospective, observational study was conducted by reviewing medical records of 18 cases of central nervous system lymphoma from seven institutions. RESULTS: Diagnosis of lymphoma was made through cerebrospinal fluid analysis, histopathology, flow cytometry of the cerebrospinal fluid, and cytology of cerebrospinal fluid, lymph node or spleen with correlated imaging. A total of 15 of 18 dogs received specific treatment other than prednisone. Three dogs underwent chemotherapy and radiation therapy after surgical decompression, five dogs underwent chemotherapy, two dogs underwent radiation therapy after surgical decompression, three dogs underwent chemotherapy after surgical decompression and two dogs underwent radiation therapy and chemotherapy. Only one dog received prednisone, and two dogs did not receive any treatment. Overall, the median survival time was 171 days (range 1 to 1942 days). CLINICAL SIGNIFICANCE: Dogs receiving any type of treatment for central nervous system lymphoma lived longer than cases described in previous historical reports. Further studies are needed to elucidate the importance of specific treatment modalities.

Pancreatic neuroendocrine tumors in twelve baboons (Papio spp.).

BACKGROUND: Pancreatic neuroendocrine tumors (PNETs) are rare in nonhuman primates and in humans. METHODS: Twenty-one PNETs from twelve female baboons (Papio spp.) from the Southwest National Primate Research Center were evaluated using histopathology and immunohistochemistry. RESULTS: Histologically, all tumors were benign and had neuroendocrine packeting. Immunohistochemical staining for synaptophysin and chromogranin was positive in all tumors evaluated (17/17). Insulin was positive in 16 of 21 tumors. Somatostatin was positive in 9 of 20 tumors. Multifocal staining for glucagon and pancreatic polypeptide was evident in a minority of tumors (6/20 and 2/17, respectively). Gastrin and vasoactive intestinal peptide were negative in all tumors evaluated. Nine tumors expressed more than one hormone marker. CONCLUSIONS: This is the first detailed pathologic study of pancreatic endocrine tumors in the baboon. The findings suggest that these tumors are generally benign and have similar morphologic and immunohistochemical features as those described in people, including the ability to express multiple hormones.

Isolation and properties of heat-labile enterotoxin(s) from enterotoxigenic Escherichia coli.

Various techniques have been applied to the detection of skin reactivity associated with heat-labile Escherichia coli enterotoxin in fermenter-grown cultures of enterotoxigenic strains in syncase medium and in trypticase soy broth. Isolated products that were homogeneous, as determined by disc electrophoresis and sodium dodecyl sulfate gel electrophoresis, differed immunologically and in physicochemical characteristics depending on the strain and medium used, even though the products had similar specific activities in skin tests and in Chinese hamster ovary cells. In support of observations on porcine E.coli enterotoxin, and in contrast to the enterotoxin of Vibrio cholerae, the products were single polypeptide chains with molecular weights ranging from approximately 35,000 ot over 100,000 daltons. Proteolytic cleavage during culture and purification might account for some of the variations observed. The isolated products were almost 10(6)-fold less active than purified choleragen in causing morphologic alterations of Chinese hamster ovary cells, approximately 1,000-fold less active in skin tests, and at least 100-fold less active in rabbit ileal loops. In addition, only 1/100 as much active protein was produced by the strains employed as by V. cholerae. It is possible that accessory or host-derived factors are required. The most effective large-scale procedure for isolation from trypticase soy broth culture supernatants was a sequence of concentration by ultrafiltration, judicious (NH4)2SO4 precipitation, gel filtration on Sephadex G-150, and gel filtration on Agarose A5m, from which the E. coli products (like choleragen) are retarded in their elution. Toxin was isolated from an enterotoxigenic strain that caused diarrhea (total volume, 60-liters) for four days in a patient who had visited Mexico.

Properties of the cholera exo-enterotoxin: effects of dispersing agents and reducing agents in gel filtration and electrophoresis.

Initial studies, by using polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS), led to the attractive hypothesis that the cholera exo-enterotoxin (choleragen) consisted of two noncovalently linked peptides of 56,000 and 28,000 molecular weight. The spontaneous toxoid (choleragenoid) appeared to be identical with the 56,000 molecular weight piece. The results appeared to be very similar to those obtained recently with diphtheria toxin. However, they did not agree with earlier studies which indicated that both the toxin and the toxoid consisted of subunits of approximately 14,000 molecular weight. More extensive investigation, by using gel filtration with (3)H-labeled toxin, ultracentrifugation, and immunologic studies, failed to support the observations of SDS-gel electrophoresis, suggesting the existence of a 28,000 molecular weight fragment which is unique to the toxin. The results were more compatible with our earlier observations regarding subunit composition. It is concluded that these proteins are relatively resistant to dissociation by SDS and need to be unfolded by prior treatment for more complete dissociation into subunits. Indirect evidence suggests that the 28,000 fragment may be a dimer, or larger aggregate, of a smaller subunit which can be integrated in the formation of choleragenoid. It is also evident that caution should be exercised in the interpretation of results, however pleasing, obtained only by SDS-gel electrophoresis.