Changes in natural killer cell activity and prostaglandin E2 levels during the progression of diethylnitrosamine-induced hepatocarcinogenesis in Fischer 344 rats

The sequential changes of natural killer cell (NK) activity and prostaglandin E2 (PGE2) during hepatocarcinogenesis induced by diethylnitrosamine (DEN) in male Fischer 344 rats were investigated. DEN at a concentration of 40 ppm was administered in drinking water for 10 weeks. At weeks 5, 10, 20 and 30, rats were autopsied and the development of glutathione S-transferase placental form positive foci (GST-P+ foci) at weeks 5 and 10 and hepatocellular tumors at weeks 20 and 30 were examined. The labeling index of bromodeoxyuridine (BrdU) an indicator of DNA synthesis, was also sequentially checked. GST-P+ foci were found to increase with age. Hepatocellular nodules increased until week 20, but by week 30 when the incidence of hepatocellular carcinoma was 100%, the incidence of nodules had decreased. BrdU positive cells also increased with age, and by week 30 when the incidence of hepatocellular carcinoma was 100%, the number of BrdU-positive cells had decreased. NK cell activity increased until week 10, but at week 20, was less than in the untreated control group. The level of PGE2 increased until week 5, but at week 10, levels were not significantly different from those seen in the untreated control group. On the basis of these results, we concluded that NK activity is closely related to the progression of hepatocarcinogenesis, but PGE2 levels show no significant change.     

Gastrointestinal autonomic nerve tumors. A clinicopathological, immunohistochemical, and ultrastructural study of 12 cases

The gastrointestinal autonomic nerve tumor (GAN tumor) is an uncommon stromal tumor of the intestinal tract and retroperitoneum first described by Herrera and associates in 1984. Distinction of GAN tumors from other gastrointestinal stromal tumors is based on electron microscopic findings. Thus far there have been 12 reported cases. We present an additional 12 GAN tumors, identified by us during 4 years. There were seven male and five female patients and they ranged in age from 10 to 85 years (mean: 58 years). Sites of the tumors were stomach (three), jejunum (two), ileum (four), mesentery (one), and retroperitoneum (two). Eight of the tumors measured > 10 cm in greatest dimension. Usually well circumscribed, the neoplasms were tan to light pink, sometimes hemorrhagic, and soft. There was a variety of histologic patterns including fascicles, palisades, and whorls. Mitotic activity varied from 0 to 23 mitosis per 10 high-power fields (HPF). Using a panel of 10 immunohistochemical stains, only vimentin was consistently positive. There was neuron-specific enolase reactivity in six and S-100 protein reactivity in two cases. All muscle markers were negative. Ultrastructural studies showed neuron-like cells with long axonic cytoplasmic processes ending in bulbous synapse-like structures containing dense-core neurosecretory granules and clear vesicles. Basement membrane was absent. These features are reminiscent of ganglia of the intestinal autonomic nervous system. The patients were followed for 5-125 months (mean of 26 months). Tumor recurred or metastasized to the liver in seven patients (58%) and four patients died with tumor. There were correlations between tumor size (> 10 cm), mitotic count (at least five per 10 HPF), and aggressive behavior.     

Cross sections of proton induced nuclear reactions on enriched 111Cd and 112Cd for the production of 111In for use in nuclear medicine

Proton induced nuclear reactions on enriched 111Cd and 112Cd have been studied up to 30 MeV in the context of routine production of the medically used isotope 111In with low and medium energy cyclotrons. The excitation functions of 111Cd(p,n)111m,gIn and 112Cd(p,2n)111m,gIn as production reactions and 111Cd(p,2n)110mIn, 111Cd(p,2n)110In, 111Cd(p,3n)109ml,m2,In, 112Cd(p,3n)110mIn, 112Cd(p,3n)110gIn as competing processes have been measured using the activation method involving the stacked-foil technique. The deduced thick target yields are compared with those obtained experimentally.     

Factors affecting serum selenium and vitamin E concentrations in dairy cows

Supplementation of selenium and vitamin E to enhance disease resistance in dairy cattle has become common, particularly to prevent periparturient reproductive disorders and mastitis. To establish reference values for serum vitamin E and selenium concentrations in postparturient dairy cattle and to determine whether serum concentrations of these micronutrients varied with season and stage of lactation, cows from a stratified random sample of 50 herds were studied for 1 year. Blood samples were collected from each of the 50 study herds twice, from the 10 most recently parturient cows or from 10% of the herd, whichever was greatest. Mean concentration of vitamin E and selenium was 2.55 micrograms/ml and 78.12 ng/ml, respectively. Vitamin E concentrations were significantly (P < 0.05) higher during the summer and fall than during the winter and spring. Selenium concentrations were significantly (P < 0.05) lower during the summer and fall than during the winter and spring. Herd, season of blood sample collection, and time since parturition were significant (P < 0.02) in explaining variation in vitamin E and selenium concentrations.