Jun Nagasao

Centroacinar and intercalated duct cells as potential precursors of pancreatic endocrine cells in rats treated with streptozotocin.

The present study examined the possibility for regeneration of pancreatic endocrine cells from centroacinar (CA) and intercalated duct (ICD) cells in rat pancreas after 5 days of continuous streptozotocin (STZ) administration. Nine rats were divided into 3 experimental groups: 1) Control group, 2) Short term recovery group; three days after STZ administration (STZ 3), and 3) Long term recovery group; ten days post-STZ administration (STZ 10). The CA and ICD cells in the STZ 3 group had swollen cytoplasm, and sometimes contained a vesicle within the core. An insulin positive signal was detected in and around the CA and ICD cells. In the STZ 3 group, cytokeratin 20 signals were co-localized with insulin signals in both CA and ICD cells. Electron microscopically, endocrine cells and small pancreatic islets were in close contact with CA and ICD cells. Systemic biophysical serum data reflected these immunohistological results. The present results suggest that CA and ICD cells are involved in the regeneration of pancreatic B cells in rats following a lesion produced by five consecutive days of STZ administration.

Distributional changes of BrdU, PCNA, E2F1 and PAL31 molecules in developing murine palatal rugae

The distribution of cells incorporating bromodeoxyuridine (BrdU) and the expression of molecules involved in the control of cell proliferation (proliferating cell nuclear antigen [PCNA], a cellular factor in F9 teratocarcinoma cells that recognizes an adenovirus E1A inducible promoter 1 [E2F1] and proliferation-related acidic nuclear protein 31 [PAL31]) during morphogenesis of the murine palatine rugae (PR) was examined histochemically. Pattern formation of the PR rudiment was initiated with cell cycle related molecules in the epithelium of the primary palate. Cells which had incorporated BrdU were detected at the outer areas of the presumptive epithelial placode (EP) and the EP at 11.5-13.5 days post coitum (dpc) and the outer areas of the PR protrusion after 14.5 dpc. The number of PCNA-positive cells at the central area of the PR protrusion decreased after 16.5 dpc. E2F-positive cells were detected at the outer areas of the PR protrusion at 15.5 and 16.5 dpc. The number of PAL31-positive cells at the presumptive EP area and the already-formed EP area was decreased at 11.5-13.5 dpc. In two dimensional histological reconstructions, PAL31 expression approximately corresponded to the distribution of BrdU-positive cells at 11.5 and 13.5 dpc. EP placode formation might be regulated by spatiotemporal cell proliferation control involving the expression of the PAL31 molecule. Following EP formation, PR development and growth control involved the expression of E2F1 and PCNA molecules.

Morphological Changes in the Rat Endocrine Pancreas within 12 h of Intravenous Streptozotocin Administration

We examined early morphological changes in pancreatic endocrine cells within 12 h of intravenous streptozotocin (STZ) administration (60 mg/kg). Thirty rats were allocated either to a control group (vehicle alone) or to one of four experimental groups tested after 3, 6, 9 and 12 h. Karyopyknosis and cytoplasmic vacuoles were first observed in β‐cell cytoplasm 3 h after STZ administration (STZ‐3 h), and the most severe damage was found in β cells at STZ‐12 h. Insulin‐positive non‐islet cells were observed near the intercalated duct (ICD) and/or centroacinar (CA) cells at STZ‐6 h and their numbers peaked at STZ‐6 h. The distribution patterns of the insulin‐positive cells and those of nestin and insulin‐like growth factor‐1 were similar and their nuclei were positive for proliferating cell nuclear antigen. Thus, ICD cells and/or CA cells reacted immediately to transform into insulin‐secreting cells to replace injured β cells (or to compensate for the lack of β cells) within 12 h of STZ administration.

Expression of Nestin and IGF-1 in Rat Pancreas after Streptozotocin Administration

The present study examines whether centroacinar (CA) and intercalated duct (ICD) cells can serve as stem cells, after administration of the diabetogenic agent streptozotocin (STZ). Thirty rats were divided into five experimental groups: (1) control, (2) 1 day after STZ (STZ‐1), (3) 3 days after STZ (STZ‐3), (4) 7 days after STZ (STZ‐7) and (5) 14 days after STZ (STZ‐14). Many small pancreatic islets were observed in the STZ‐7 group than in the other experimental groups, and many of these small islets were in close contact with ICD and CA cells. A higher number of nestin, insulin‐like growth factor‐1 (IGF‐1) and IGF‐1‐receptor positive ICD and CA cells were observed at STZ‐3 and STZ‐7 than at the others. These expression patterns coincided well with the proliferating cell nuclear antigen pattern. The results suggest that rat pancreatic endocrine cells after damage by STZ administration might be recovered from newly generated cells derived from ICD and CA cells.

Morphological Relationship Between Intercalated Duct and Pancreatic Islet in Streptozotocin and/or Camostat Mesilate Administrations in the Chicken

Present electron microscopical and immunocytochemistrical studies elucidated some morphological relationship between intercalated duct (ICD) and pancreatic islet cells in the chicken in streptozotocin (STZ) and/or camostat mesilate (CM) administrations. Twenty‐one chickens were set into four experimental groups: (1) control group, (2) STZ administration group, (3) CM administration group, and (4) STZ + CM administration group. Cytoplasms of ICD cells stained more strongly with eosin in STZ administration group than other groups, and electron‐dense materials and intercalated processes between ICD and islet cells were also increasing in time dependence in STZ administration. Number of pancreatic islet in STZ + CM co‐administration was about 3.1 times larger than other groups. Many small sized cells were detected at surrounding area of ICD and they incorporated 5‐bromo‐2′‐deoxyuridine better than other experimental groups. Present morphological data suggested that ICD cells might support some tolerances of pancreatic endocrine cells against toxic substances and also involve in regeneration of new pancreatic islet cells in STZ + CM co‐administration.

Characterization of Monoclonal Antibodies Against Gnathostoma nipponicum

Monoclonal antibodies (mAbs) were produced against the proteins of advanced third-stage larvae (AdL3) of Gnathostoma nipponicum. Six mAbs (Gn2C3, Gn2H3, Gn4C3, Gn4E9, Gn5H1, and Gn10B7) were obtained as determined by enzyme-linked immunosorbent assay (ELISA). Gn4E9 and Gn5H1 seemed to be genus-specific, as they did not cross-react with Anisakis sp., Dirofilaria immitis, Gongylonema pulchrum, Toxocara canis, Trichinella sp., Trichuris vulpis, Metagonimus sp., or Spirometra erinaceieuropaei by ELISA. Immunohistochemistry showed that Gn2C3, Gn4E9, and Gn5H1 reacted strongly with the central esophagus; Gn2H3 reacted with cuticle, muscle, intestine, and the cervical sac; and Gn4C3 and Gn10B7 reacted with cuticle, muscle, esophagus, intestine, and the cervical sac of AdL3. In Western blotting analysis, Gn2C3, Gn4E9, and Gn5H1 reacted to 60-, 53-, 46-, and 41-kDa proteins; Gn4C3 reacted to the AdL3 protein of G. nipponicum (>42 kDa). Moreover, proteins purified using a mAb Gn4E9 immunoprecipitation method (sizes 60-, 53-, 46-, and 41-kDa) were used as antigens in ELISAs. A significant difference (P < 0.01) was shown between mouse sera infected with G. nipponicum and sera infected with Trichnella sp. or not infected. These results provide a rationale for evaluating esophageal proteins for the development of diagnostic methods for detecting G. nipponicum or Gnathostoma sp. infections.

A case of a giant mass in the lumbar region of a newborn calf

The present report describes a newborn calf with spina bifida that presented with a giant mass of the lumbar region, as well as subsequent gross, histological, and immunohistochemical examinations. A malformed Japanese black calf (estimated weight = 20 kg) was euthanized immediately after birth. A gross evaluation revealed a giant mass (approximately 60 cm × 30 cm × 15 cm) covered by the hair coat in the lumbar region and connected with the hair coat of the trunk. The mass surface was divided by a deep polygonal groove and externally resembled a lobulated kidney. Histology and immunohistochemistry revealed that the giant mass comprised a vessel, bronchiolus lined with cuboidal epithelium, and small alveolus. Bone bleaching revealed various abnormalities, including spina bifida, vertebral fusion, vertebral deformity, vertebral malformation, vertebral scoliosis, and coxal bone malformation. Following a suggestion that the giant lumbar region mass was occupied by lung tissue, this case was considered to involve an asymmetric conjoined duplicitas that resulted in a very rare dichotomous spondylosis malformation.

Comb Atrophy after Bile Duct Ligation in Chickens

Gross, histological, and immunohistochemical changes in the combs of chickens after bile duct ligation (BDL) are described. Gross reductions in comb size and volume and lower serum testosterone levels were evident in chickens after BDL. Histologically, atrophic combs were characterized by reduced blood capillary diameter, decreased acid mucopolysaccharides, thinning of the stratum germinativum of the epidermis and dermis, and reduced immunostaining intensity of androgen receptors. These results suggest that the affected cells in atrophic combs are androgen targets. BDL caused testicular atrophy in chickens, a primary complication of liver disease, and the resultant low serum testosterone levels subsequently caused atrophy of the comb. In other words, the atrophy of the comb observed in BDL chickens was a secondary complication of liver dysfunction that simulated the effects of liver disease.