Kazuhiro Shichinohe

Spontaneous diabetes-like syndrome in WBN/KOB rats.

SummarySpontaneous hyperglycemia, glycosuria, hypoinsulinemia, and glucose intolerance were observed in some WBN/Kob rats, at about 9 months of age, and in all at the age of 17 months. Females did not present this pathology. Histopathologic examination of the pancreas revealed severe changes in male rats at the age of 3 months. Between 3 and 6 months of age a distinct infiltration of inflammatory cells was found around islets and among adjacent acinar cells. At the same time, marked fibrosis was seen around the pancreatic ducts and blood vessels. With advancing age the fibrous tissue gradually invaded extensive areas of the pancreas where also the islets became involved in fibrotic degeneration. At 17 months of age and later, an obvious decrease in islet number and size (less than 50 µ in diameter) was observed, even in relatively unaffected areas of the organ. Frequent bilateral cataracts began to appear at about 15 months of age. Opacities were first observed in the periphery of the lens, then increased rapidly in intensity and extended centripetally. Nineteen-month-old male rats were hypersensitive to exogenous insulin, but showed no significant decrease in blood glucose level when treated with oral tolbutamide. These results suggest that these rats suffered from a decreased insulinogenic response.

Renal lesions in a strain of spontaneously diabetic WBN/KOB rats

SummaryIn WBN/Kob strain rats, only males spontaneously develop hyperglycemia, glycosuria, hypoinsulinemia and glucose intolerance from about nine months of age. The kidneys of male rats of this strain were histopathologically studies to evaluate the changes which appeared as complications of diabetes mellitus. Thickening of the basement membrane, increase of the mesangial matrix and fibrin-cap lesions were noted in the glomeruli. Armanni-Ebstein degeneration was occasionally found in the tubules. Linear deposition of plasma components such as IgG and albumin in the basement membrane of the glomeruli, tubules and Bowman’s capsule characterized the immunohistological pattern. These findings are similar to the findings in diabetic nephropathy in humans. Since the onset of diabetes mellitus in the strain is slow and symptoms are generally mild, insulin administration is usually not necessary for survival. This strain, therefore, appears to be an important animal model for the study of complications of diabetes in humans.

Cerebellar ataxia due to Toxocara infection in Mongolian gerbils, Meriones unguiculatus

We assessed the usefulness of gerbils as an experimental model for neurologic toxocarosis. Mongolian gerbils, Meriones unguiculatus, infected with Toxocara canis or Toxocara cati (1000 eggs/gerbil) showed progressive neurologic disorders from 50 days after infection in T. canis-infected gerbils or from 120 days after infection in T. cati-infected gerbils. The incidence of the onset was 6 of the 13 gerbils (49%) in the T. canis-gerbils and 5 of the 7 gerbils (71%) in the T. cati-gerbils. Histopathologically, the cerebellum was the most affected in both groups. We observed loss of Purkinje cells, glial nerve fibers, and nerve sheaths. We also found foci consisting of aggregated macrophages scattered in the white matter of the cerebellum. The affected gerbils showed ataxia and ultimately died of cachexia. Our findings suggest that irreversible neurologic toxocarosis in gerbils can be induced by infection with either T. canis or T. cati.

Ultrastructural changes and immunohistochemical localization of advanced glycation end products in the heart of streptozotocin-treated Mongolian gerbils.

This study was designed to clarify the developing mechanism of cardiomyopathy and vasculopathy in streptozotocin-treated Mongolian gerbils. Twenty male Mongolian gerbils (MG; 10–12 weeks old) were used, and 150 mg/kg of streptozotocin (STZ) was injected into the left femoral vein. Six control male MG were injected intravenously with normal saline. The animals showed severe hyperglycemia (up to 330 ± 96.4 mg/dl) by 1 week after streptozotocin administration. At 1 week after STZ treatment, cardiomyocytes revealed no significant change, but unclear striated structures were demonstrated in cardiomyocytes at 4 weeks. After 1 year, anisocytosis was observed, and in the perinuclear region granular components were stained positively with periodic acid-Schiff reagent. Ultrastructurally, at 4 weeks and 1 year after STZ treatment, cardiomyocytes were irregular in size, and oval amorphous and lysosomal electron-dense bodies were observed in perinuclear and cytoplasmic regions. In coronary arteries, endothelial and medial cells revealed increased vesicles and intercellular collagen fibrils. Capillaries showed slight swelling of endothelial cells associated with the lamellar thickening of basement membrane and collagen fibrils in the perivascular regions. Immunohistochemically, advanced glycation end products (AGE) were observed in the cytoplasm of vascular and heart cells, and ultrastructurally the reaction products were demonstrated in the endoplasmic reticulum and lysosomes of cardiomyocytes and vascular cells in the STZ-treated Mongolian gerbils. AGE may play an important role not only in angiopathy but also in cardiomyopathy of STZ-treated Mongolian gerbils after STZ treatment.

Moderation of chemo–induced cancer by water extract of dried shark fin : anti–cancer effect of shark cartilage

Abstract It is now well recognized that matrix metalloproteinase (MMP) plays significant roles in cancer progression. Shark cartilage contains the MMP inhibitors. On the basis of these findings, oral administration of the shark cartilage has been proposed to suppress cancer progression and improve quality of life of cancer patient. Now, the “shark cartilage therapy” is popular in USA, Japan and other countries. However, there are conflicting data on the effectiveness of the therapy. In addition, knowledge on the active component responsible for the potential anti-cancer effect is limited. To facilitate the further study on the anti-cancer effect of shark cartilage and utilization of shark fin cartilage, a by-product from fisheries industry, moderation of chemo-induced cancer by the water extract of dried shark fin is discussed.