Comparison of gastritis and gastric epithelial proliferation in Helicobacter heilmannii-infected nude and BALB/c mice

Gastric mucosal hypertrophy/nodular hyperplasia occurs as a consequence of Helicobacter infection in mice and humans. The pathogenesis of this hyperplastic response is not understood. To determine the role of host cellular immunity in gastric mucosal hypertrophy/hyperplasia, 6-8-week-old female euthymic BALB/c (n = 30) or NIH athymic nude (n = 40) mice were inoculated with H. heilmannii. Equal numbers of uninoculated mice of each strain served as controls. Mice from each group were euthanatized at 0.5, 6, 12, and 18 months postinoculation (PI). Lymphoplasmacytic gastritis and lymphoid follicle development were less severe in nude mice than in euthymic mice at <6 months PI. The prevalence of gastritis at 0.5, 6, 12, and 18 months PI was 0%, 17%, 67%, and 88%, respectively, in infected nude mice and 33%, 83%, 71%, and 100%, respectively, in infected BALB/c mice. CD4+ T cells in infected nude mice were evident at > or =6 months PI but were less numerous than in infected BALB/c mice at comparable time intervals. However, numbers of CD4+ T cells increased substantially throughout the experiment in infected BALB/c mice. The prevalence of nodular mucosal hyperplasia at 0.5, 6, 12, and 18 months PI was 0%, 0%, 33%, and 20%, respectively, in infected nude mice and 0%, 33%, 80%, and 80%, respectively, in infected BALB/c mice. Nodular hyperplasia occurred in association with the appearance of chronic lymphoplasmacytic inflammation and CD4+ T cells at 12 and 18 months PI in nude mice. H. heilmannii-associated gastritis and mucosal remodeling is reduced in immunodeficient mouse strains lacking normal CD4+ T cell numbers as compared with the response in immunocompetent mice. Additionally, CD4 immunocompetence is an integral aspect of the mucosal hypertrophy/nodular hyperplasia in experimental H. heilmannii-associated disease of mice.     

Absorption kinetics of regular and isophane (NPH) insulin in the normal dog

Absorption kinetics of regular and isophane (NPH) insulins were evaluated in seven normal fasted dogs by measuring serial serum concentrations of insulin and glucose following the subcutaneous administration of regular and NPH insulins. These results were compared to serum insulin values determined after injecting similar doses of regular insulin intravenously. Regular insulin was better absorbed than NPH insulin (mean bioavailability index 64.6% vs. 41.1%, P less than .01) resulting in a significantly greater maximal increase in mean circulating insulin concentrations above baseline values (362.2 microU/ml vs. 147.8 microU/ml, P less than .05). The time interval between insulin injection and return of serum insulin values to basal concentrations was also significantly shorter for regular than for NPH insulin (4.9 hr vs. 8.6 hr, P less than .05). However, there were no significant differences between regular and NPH insulins in time to reach peak serum insulin concentrations, maximal reduction in serum glucose concentrations, or time of lowest circulating glucose levels. The results of this study support previously accepted values for time-action characteristics of regular insulin, but suggest that NPH insulin may have an earlier peak and shorter duration of action than has previously been proposed in the dog.     

Insulin-Secreting Pancreatic (Islet Cell) Carcinoma in a Cat

A functional, insulin-secreting pancreatic (islet cell) carcinoma was diagnosed in a 17-year-old male Siamese cat. Diagnosis was made on the basis of clinical signs (i.e., seizures and stupor) that resolved temporarily after correction of hypoglycemia with feeding or intravenous administration of glucose, the finding of an inappropriately increased serum insulin concentration in the face of hypoglycemia, and prolonged resolution of hypoglycemia after surgical removal of the tumor. Primary islet cell tumor of the pancreas was confirmed by biopsy. The cat died 18 months later, and necropsy revealed metastases to regional lymph nodes and liver. Specimens of the tumor and metastatic lesions both stained positively for insulin.     

Accurate Chromatographic Method for Sorption Isotherms and Phase Equilibria

Partition coefficients can be determined with accuracy by a "tracerpulse" method in which the retention volume of a tracer of the respective species is measured. The method is applicable to multicomponent equilibria and can be used at elevated temperature and pressure. A less accurate "differential" method not requiring a tracer is also described.     

Serum thyroid hormone concentrations in clinically normal dogs after administration of freshly reconstituted vs previously frozen and stored thyrotropin

Concentrations of serum thyroxine (T4) and 3,3',5-triiodothyronine (T3) were determined in 7 clinically healthy adult dogs before and after administration of freshly reconstituted thyrotropin (TSH) and TSH that had been previously reconstituted and frozen for 1, 2, and 3 months. The 4 TSH response tests were performed at 30-day intervals by collecting blood samples for serum T4 and T3 determinations before and 4 and 6 hours after IV administration of TSH (0.1 U/kg of body weight). Baseline serum concentrations of T4 and T3 were similar at each of the 4 sample collection times over the 3-month period of the study. Mean serum concentrations of T4 and T3 increased significantly (P less than 0.01) over baseline values after administration of freshly reconstituted TSH or TSH that had been previously frozen for 1, 2, or 3 months. Significant difference was not found in the mean post-TSH serum T4 or T3 concentration after injection of freshly reconstituted TSH or TSH that had been previously frozen for 1, 2, or 3 months. In 2 of the 7 dogs, mild reactions--mild ataxia and weakness--were observed during the last of the series of TSH response tests (ie, after IV administration of TSH that had been previously frozen for 3 months). Results of this study suggest that for use in dogs, reconstituted TSH stored at -20 C maintains adequate biological activity for at least 3 months. The ability to store reconstituted TSH for a longer period than the recommended 48 hours represents an economic advantage, because it allows clinicians to perform more TSH response tests per vial of TSH.