Characterization of pancreatic islet cell tumors and renal tumors induced by a combined treatment of streptozotocin and nicotinamide in male SD rats

We herein investigated the histopathological features, including proliferative activity and immunoexpression, of pancreatic islet cell tumors (ICTs) in male SD rats induced by streptozotocin (STZ) and nicotinamide (NA), and discussed their relevance to biological behaviors and prognoses. A total of 70 and 43% of rats developed ICTs 37–45 weeks after the treatment with STZ (50 or 75 mg/kg, i.v.) and NA (350 mg/kg, twice, p.o.), respectively. Among the islet tumors observed in the STZ/NA-treated groups, 75% were adenomas, while 25% were carcinomas. Most STZ/NA-induced carcinomas were characterized by well-differentiated tumor cells with/without local invasion into the surrounding tissues, and weak proliferative activity. No outcome such as distance metastasis and death was noted. All of the ICTs strongly expressed insulin, part of which had hormone productivity; however there were no hypoglycemia-related clinical signs such as convulsion in these rats 36 weeks after the treatment. These results suggested that rat ICTs induced STZ/NA have small impact on biological activity or prognosis. STZ/NA treatment significantly increased of focal proliferative lesions in the kidney, liver and adrenal glands other than pancreatic islets. Of the STZ/NA-induced kidney tumors, more than 60% were renal cell adenomas, and many of them were basophilic type. The incidence of eosinophilic or clear cell type of tumors was less than 10%, respectively. Immunohistochemical analyses revealed that many of the STZ/NA-induced basophilic type of renal tumors were derived from proximal tubules, whereas the clear cell and eosinophilic types were derived from collecting tubules.     

A case of refractory polyarteritis nodosa successfully treated with rituximab

A 59-year-old man who presented with continuous fever, livedo reticularis, and left leg ischemia with multiple tibial artery stenosis and renal artery aneurysm, as demonstrated by arteriography, was diagnosed with polyarteritis nodosa (PAN) 6 years ago. Although he frequently relapsed in spite of intensive immunosuppressive therapies, the disease activity of PAN was controlled with repeated rituximab (RTX) therapies and steroid doses were tapered safely. Peripheral CD19⁺ B-cells disappeared soon after the 1st administration of RTX. Although CD19⁺ B-cells remained absent, 3.1% of CD3⁺CD20⁺ T-cells were observed in the peripheral blood prior to the 2nd administration of RTX. Recent studies have suggested the pathogenic role of CD3⁺CD20⁺ T-cells in autoimmune diseases in the context of RTX therapy; therefore, their roles in the pathogenesis of PAN also need to be considered.     

Periodontal disease and pneumonia mortality in haemodialysis patients: A 7‐year cohort study

Aim

To evaluate the association between periodontal disease and pneumonia mortality in haemodialysis patients.

Materials and Methods

This prospective cohort study included 211 patients (mean age, 64.4 years) undergoing haemodialysis at a single medical centre. The patients underwent a baseline clinical dental examination in 2008 and were then followed up until July 2015. Periodontal disease was defined as the presence of clinical attachment loss of ≥4 mm in ≥30% of the probed sites. The primary endpoint, that is death from pneumonia, was determined by reviewing death certificates and was analysed using the competing‐risks regression model.

Results

At baseline, 92 patients (43.6%) had periodontal disease. The median follow‐up period was 84 months (interquartile range, 36–86 months). Of the 68 deaths that occurred, 21 were from pneumonia. The multivariable competing‐risks regression model showed that periodontal disease was significantly associated with death from pneumonia (adjusted subhazard ratio, 3.49; 95% confidence interval, 1.14–10.64), after adjusting for other baseline health characteristics.

Conclusions

The results of this study suggest that periodontal disease is independently associated with pneumonia mortality in haemodialysis patients. Future studies evaluating the potential effect of oral interventions for periodontal health improvement on pneumonia in haemodialysis patients would be of great interest.