Development of the chick pancreas with regard to estimation of the relative occurrence and growth of endocrine tissue

Endocrine cells in chick pancreas were observed to map their distribution during development and to perform morphometric studies starting on embryonic day 5. The ratio of exocrine to endocrine tissues first prevailed in favour of the endocrine ones, and changed abruptly after day 9 when rapid growth of exocrine tissue began. Endocrine tissue was formed of two types of islets. The 'light' (or B) islets were composed of insulin-immunoreactive cells, completed perhaps by a few somatostatin-immunoreactive cells occurring on the periphery. The majority of the somatostatin- and glucagon-immunoreactive cells were present in the 'dark' (or A) islets. Endocrine elements were also scattered as single cells over the pancreas. Sporadically, the endocrine cells established contacts with exocrine ducts. In morphometric analysis, volume density of insulin-, glucagon-, and somatostatin-immunoreactive cells was measured, and ratios were calculated between particular components. The volume density of endocrine cells and their ratio appeared stable in individual lobes but varied significantly between each other. Increase of the glucagon volume density is exponential, whereas insulin increases almost linearly especially in splenic lobe. The process results in the increase of the hormone-immunoreactive cell volume density in favour of glucagon-immunoreactive cells typical for birds.     

鸭胰腺内高血糖素—,胰岛素—和生长抑素—免疫反应细胞的形态及分布

用ABC免疫组织化学方法,对1 周龄绍鸭胰腺内的高血糖素(A)、胰岛素(B)和生长抑素(D)免疫反应细胞的形态及分布进行了观察。结果表明,上述3 种细胞在全胰的分布及形态有差异。A 细胞主要成群散在于A 胰岛,少数位于混合型胰岛的边缘。D 细胞主要散在于A 胰岛中,少数位于B胰岛和混合型胰岛的边缘。B细胞主要呈团块状分布于B胰岛,少数位于混合型胰岛的中央。在胰外分泌部有散在的A 和D 细胞,位于腺泡及导管上皮细胞之间或结缔组织中。A 细胞形态各异,以多边形为主,多数细胞伸出形态多样的胞质突起,伸达胰岛或其他细胞间。D细胞的形态与A 细胞相似。B细胞形态均一,呈圆形或卵圆形,未见胞质突起,在外分泌部未见到B细胞。     

Ultrastructure of pancreatic alpha and beta cells in young quails (Coturnix coturnix japonica) fed aflatoxin

The present investigation was undertaken to assess the effects of aflatoxin (AF) containing diets on alpha and beta cells of the endocrine pancreas in young quails by means of light and electron microscopy. A total of thirty quails were divided into 3 groups, each comprising 10 animals. Total AF was incorporated into the diet of these groups, at dosages of 0 (control, group 1), 2.5 (group 2), and 5.0 (group 3) mg AF/kg feed. The chicks were housed in electrically heated battery cages and exposed to light for 24 h from hatching to 3 weeks of age. Quails consumed the diets and water ad libitum. Electron microscopic examinations demonstrated degranulation of alpha cells, decrease in the size and number of secreting granules, and increase in the number of free ribosomes and polisomes in the animals of group 2 and 3. In beta cells, the numbers of free ribosomes and polisomes decreased, whereas the number of mature granules increased in the animals of group 3. Mononuclear cell infiltrates were observed in the periphery of capillaries and around endocrine islets in the experimental groups. Furthermore, capillaries of the animals in group 2 and 3 were dilated at all sides of both alpha and beta islets. According to the results of this study, the addition of aflatoxin to the diets of quails at dosage of 2.5 and 5 mg AF/kg leads to significant changes in pancreatic alpha and beta cells. These changes may exhibit adverse effect on the metabolism of carbohydrates in poultry.     

An Immunohistochemical Survey of Catecholamine-synthesizing Enzyme-immunoreactive Nerves and Endocrine Cells in the Bovine Pancreas

The distribution of catecholamine-synthesizing enzyme-immunoreactive nerves and endocrine cells in the pancreas of the calf and cow was studied immunohistochemically using antisera against tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH). TH- and DBH-immunoreactive nerve fibres were abundant both within and around the islet of Langerhans. A few TH- and DBH-immunoreactive nerve fibres were seen around the large islets characteristic of calf pancreas, but the majority of cells in the large islets, and some in islets of Langerhans, showed TH immunoreactivity. In the exocrine pancreas, both TH- and DBH-immunoreactive nerve fibres were distributed randomly among the acini, with the DBH-immunoreactive fibres being more numerous. Abundant TH- and DBH-immunoreactive nerve fibres were seen in close association with blood vessels and in the connective tissue around the interlobular duct. Immunoreactivity for both enzymes was also observed in the nerve cell bodies and fibres of the intrapancreatic ganglia. The findings suggest an important role for catecholamines in the regulation of bovine pancreatic function.     

Immunoreactivity of cytotoxic T-lymphocyte antigen 2 alpha in mouse pancreatic islet cells

Cells of the pancreatic islets produce several molecules including insulin (beta cells), glucagon (alpha cells), somatostatin (delta cells), pancreatic polypeptide (PP cells), ghrelin (epsilon cells), serotonin (enterochromaffin cells), gastrin (G cells) and small granules of unknown content secreted by the P/D1 cells. Secretion mechanism of some of these molecules is still poorly understood. However, Cathepsin L is shown to regulate insulin exocytosis in beta cells and activate the trypsinogen produced by the pancreatic serous acini cells into trypsin. The structure of the propeptide region of Cathepsin L is homologous to Cytotoxic T-lymphocyte antigen-2 alpha (CTLA-2 alpha) which is also shown to exhibit selective inhibitory activities against Cathepsin L. It was thought that if CTLA-2 alpha was expressed in the pancreas; then, it would be an important regulator of protease activation and insulin secretion. The purpose of this study was, therefore, to examine by immunohistochemistry the cellular localization and distribution pattern of CTLA-2 alpha in the pancreas. Results showed that strong immunoreactivity was specifically detected in the pancreatic islets (endocrine pancreas) but not in the exocrine pancreas and pancreatic stroma. Immunostaining was further performed to investigate more on localization of Cathepsin L in the pancreas. Strong immunoreactivity for Cathepsin L was detected in the pancreatic islets, serous cells and the pancreas duct system. These findings suggest that CTLA-2 alpha may be involved in the proteolytic processing and secretion of insulin through regulation of Cathepsin L and that the regulated inhibition of Cathepsin L may have therapeutic potential for type 1 diabetes.     

绍鸭胰腺胰高血糖素免疫反应细胞生长发育的显微图像分析

用免疫组织化学ＡＢＣ法，显示绍鸭胚发育期间胰内高血糖素细胞，观察Ａ细胞的形态及分布；用显微图像分析仪测定Ａ细胞的积分光密度值；并求各时期Ａ细胞的平均积分光密度值，再作统计学分析。结果表明：Ａ细胞形态多样，但以多面形为主，并上侈种形式的胞 质突起。本文显示了胰腺Ａ细胞在胚后发育期间的发变化规律。为胃肠胰内分泌系统的功能研究提供动态变化的基础资料。     

Immunocytochemical component of endocrine cells in pancreatic islets of horses

The endocrine cell components in the pancreatic islets of the following 4 pancreatic regions of the horse were investigated by immunohistochemical methods: lobus pancreatis sinister (left lobe); lobus pancreatis dexter (right lobe); and 2 regions of Corpus pancreatis (body), the duodenal lobe which lies along the cranial duodenal flexure and descending duodenum, and the intermediate lobe which is situated around the portal vein. The islets in the left and intermediate lobes contained a central mass of glucagon cells surrounded by insulin cells, a few somatostatin cells and sporadic pancreatic polypeptide (PP) cells. On the other hand, the islets in the duodenal lobe were small in size compared with the other 3 regions, and were predominant in insulin and pancreatic polypeptide (PP) cells, but almost lacked in glucagon cells. These findings suggested that the duodenal lobe was derived from the ventral pancreatic primordium, and the left and intermediate lobes were originated from the dorsal pancreatic primordium. In the right lobe, the composition and distribution of the islet cells were almost the same as those in the left and intermediate lobes, but there were several lobules containing numerous PP cells as seen in the duodenal lobe.     

Immunohistochemical localization of neuropeptides in bovine pancreas

The occurrence and density of distribution of nerves and endocrine cells that are immunoreactive for neuropeptides in the bovine pancreas were studied by immunohistochemistry. The six neuropeptides localized were galanin (GAL), substance P (SP), methionine-enkephalin (MENK), neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP). The exocrine pancreas was shown to have an appreciable number of GAL- and SP-immunoreactive nerve fibres but few fibres showing immunoreactivity for VIP and CGRP. Numerous MENK-, GAL-, SP-, and NPY-immunoreactive nerve fibres were seen in the endocrine portion of the pancreas. Nerve cell bodies in the intrapancreatic ganglia showed immunoreactivity for all of the neuropeptides except CGRP. Endocrine cells showing immunoreactivity for GAL and SP were observed in the large islets and islets of Langerhans, respectively. The present results indicate a characteristic distribution of neuropeptides in the bovine pancreas, which may regulate both exocrine and endocrine secretions of pancreas.     

Immunohistochemical morphometry of pancreatic islets in the cat.

The application of immunohistochemical technique with antisera for glucagon (Glu), insulin (Ins), somatostatin (Som) and pancreatic polypeptide (PP) to serial sections of the cat pancreas permitted the quantitative evaluation of the population of 4 endocrine cell types and that of the area, larger diameter and density of islets. The pancreas was divided macroscopically into the 4 portions, duodenal, gastric, anastomotic and splenic. The duodenal portion was characterized by the localization of PP-immunoreactive (IR) cell-rich islets, the dissemination of PP-IR cells in the exocrine parenchyma and the absence of Glu-IR cells. In the duodenal portion, the area, the larger diameter and the density of islets were significantly smaller than those in the other 3 portions. On the contrary, the other 3 portions were marked with the deficiency of PP-IR cells and the existence of Glu-IR cell-rich islets. Ins-IR cells, identified as compact cell masses without any other types of cells, occupied a major part of every islet, composing much the same population throughout the 4 portions. The Som-IR cell population appeared to be closely in parallel with the Glu-IR cell population in all of the portions. It is concluded that all islets are similar in the Ins-IR cell population, but different in the complementary arrangement of Glu- and PP-IR cells. Based on this difference, 2 types of islets can be classified.     

Primary chondrosarcoma in the liver of a dog

Primary chondrosarcoma was found in the quadrate lobe of the liver of a 6-year-old, intact, male Golden Retriever. At 6 months after partial hepatectomy, recurrence in the liver occurred. The dog died of its systemic metastases 10 months thereafter. Histologically, the hepatic mass revealed neoplastic chondrocytes with abundant chondroid matrix, and there were few myxoid areas where the cellularity and pleomorphism of the neoplastic cells were more prominent. The neoplastic cells were positive for periodic acid-Schiff and were immunohistochemically positive for vimentin and S-100 protein; the matrix was deeply stained for alcian blue and was metachromatic for toluidine blue stain. This tumor might be derived from pluripotent mesenchymal cells in the connective tissue of the liver. To the best of our knowledge, in all mammalians, including humans, this is the first report of extraskeletal chondrosarcoma primarily arising in the liver.     

Immunohistochemical, ultrastructural, and hormonal studies on the endocrine pancreas of voles (Microtus arvalis) with monosodium aspartate-induced diabetes.

A single subcutaneous administration of monosodium aspartate (MSA) to 30 neonatal voles, Microtus arvalis Pallas, induced a diabetes mellitus in 50% of the treated animals in early adulthood. The voles (18 males and 12 females) were weaned at 3 weeks of age and fed pellets for Herbivora and cubed hay. Diabetic voles with glycosuria (nine males and six females) were classified into two groups according to the duration and grade of glycosuria. One group had slight diabetes with glycosuria (+: 0.1%) for 1 week and the other severe diabetes with marked glycosuria ( : greater than or equal to 0.5%) for over 4 weeks. Pancreatic islets of diabetic voles (n = 7) were examined immunohistochemically, light microscopically, and electron microscopically. Blood glucose concentration and tissue content of insulin, glucagon, and somatostatin were also measured. Slightly diabetic voles (n = 3) had enlarged islets, that, viewed by light microscopy, were characterized by hypertrophy and hyperplasia of beta cells with moderate degranulation. No changes were observed in the peripherally located alpha and delta cells; the voles were moderately hyperglycemic, and they had decreased pancreatic insulin content. Severely diabetic voles (n = 4) that had marked hyperglycemia and almost complete loss of insulin content showed marked vacuolation and degranulation of beta cells. In addition, altered distribution of alpha and delta cells from the periphery of the islets to their interior was noted. Ultrastructural examination revealed features compatible with those of hyperfunction of beta cells in the slightly diabetic voles and marked degeneration of beta cells with glycogen accumulation in the severely diabetic voles.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunohistochemical detection of the enzyme glutamic acid decarboxylase and hormones of the islets of Langerhans in spontaneous insulin-dependent diabetes mellitus in cattle

Immunohistochemical expression of glutamic acid decarboxylase (GAD) enzyme was detected in the pancreatic islets of 12 cattle with spontaneous insulin-dependent diabetes mellitus (IDDM). The most characteristic changes were atrophy and decreased number of pancreatic islets, enlarged islets with vacuolated beta cells, and lymphocytic islet adenitis. Atrophied islets were composed of small islet cells without cytoplasmic insulin-positive granules. Immunohistochemically, GAD was not found in the cytoplasm of atrophied islet cells. Furthermore, enlarged islets consisting of islet cells with vacuolated cytoplasm were frequently observed. The cytoplasm of vacuolated cells contained very few GAD- and insulin-positive granules, indicating beta cell destruction. Enlarged islets with mild lymphocytic infiltrates were frequently observed. These findings suggest that islet cells in cattle with IDDM lose their insulin synthesis function and their ability to regulate hormonal secretion of alpha and delta cells.     

Effects of corticosteroids on lymphocyte subpopulations and lymphokine secretion in chickens.

Various effects of glucocorticosteroids on the avian immune system were examined in chickens treated intramuscularly with 0.1 to 2.5 mg dexamethasone or prednisolone. Kinetic changes in body weight gain, percentages of lymphocyte subpopulations, and T-cell functions were examined following treatment with dexamethasone or prednisolone every other day. Chickens treated with dexamethasone or prednisolone showed a decrease in body-weight gain compared with age-matched, untreated chickens. In general, the total number of splenic lymphocytes of chickens treated with the two drugs was significantly lower than in controls in a dose-dependent manner. Flow cytometric analysis of splenic lymphocyte subpopulations revealed that the percentages of lymphocytes expressing CD8, gamma delta T-cell receptor, Ia, or IgM antigens and natural killer cells were lower in dexamethasone-treated chickens than in the controls, whereas the percentages of T lymphocytes bearing CD3, CD4, or alpha beta TCR antigens were higher. Furthermore, splenic T cells obtained from dexamethasone-treated chickens showed a significant depression in concanavalin A-induced lymphoproliferation and interleukin 2 and gamma-interferon production. The results characterize a variety of immunosuppressive effects of glucocorticoids on the avian immune system.     

Histopathological Changes in the Pancreas from a Spontaneous Hyperglycemic Cynomolgus Monkey

Morphological and immunohistochemical examinations were carried out on the pancreas of a hyperglycemic 5-year-old male cynomolgus monkey. Body weight gradually decreased from 6 months before termination, accompanying a slight reduction in food consumption and anorexia for the last 2 days. The blood glucose level was markedly elevated when examined at termination. Histopathologically, in the exocrine pancreas, diffuse hyperplasia of centroacinar and intercalated duct cells and diffuse atrophy of acinar cells with sporadic apoptosis were observed, although most centroacinar and intercalated duct cells were proliferating cell nuclear antigen (PCNA)-positive in both the present case and age-matched control animals. In the endocrine pancreas, the islets tended to be hypertrophic, with an increase in insulin-positive cells in comparison with the age-matched control animals. PCNA-positive cells also tended to increase in the islets, although positive cells for phospho-histone H3, a marker for mitotic cells, were not detected in the endocrine and exocrine pancreas. Moreover, neither inflammation nor amyloidosis was noted in the islets. In conclusion, the present case probably suffered from early-stage type 2 diabetes mellitus, and it provides fundamental information concerning pancreatic histopathology under insulin-related derangement in monkeys.     

Pasteurellosis in bobwhite quail

A flock of 5000 six-week-old bobwhite quails (Colinus virginianus) experienced high mortality (52%) over a 2-day period. Mortality was 99% within a 6-day period. Clinical signs were depression followed shortly by death. Gross lesions observed in dead quails were congested lungs and, in a few cases, mottled livers. Histopathologic examination revealed severe, diffuse, heterophilic interstitial pneumonia and multifocal areas of hepatic and splenic necrosis with numerous intracellular and extracellular short bacterial rods. Serotype 3, 4, 15, 16, Pasteurella multocida, isolated from the index case, caused 50% mortality in experimentally inoculated bobwhite quails within 9 to 24 hours. This report indicates that pasteurellosis can cause peracute disease in bobwhite quails with very high mortality.     

Expression patterns of influenza virus receptors in the respiratory tracts of four species of poultry

The primary determinant of influenza virus infectivity is the type of linkage between sialic acid and oligosaccharides on the host cells. Hemagglutinin of avian influenza viruses preferentially binds to sialic acids linked to galactose by an α-2,3 linkage whereas hemagglutinin of human influenza viruses binds to sialic acids with an α-2,6 linkage. The distribution patterns of influenza receptors in the avian respiratory tracts are of particular interest because these are important for initial viral attachment, replication, and transmission to other species. In this study, we examined the distribution patterns of influenza receptors in the respiratory tract of chickens, ducks, pheasants, and quails because these species have been known to act as intermediate hosts in interspecies transmission. Lectin histochemistry was performed to detect receptor-bearing cells. Cell-specific distribution of the receptors was determined and expression densities were compared. We observed species-, site-, and cell-specific variations in receptor expression. In general, receptor expression was the highest in quails and lowest in ducks. Pheasants and quails had abundant expression of both types of receptors throughout the respiratory tract. These results indicate that pheasants and quails may play important roles as intermediate hosts for the generation of influenza viruses with pandemic potential.     

The distribution and heterogeneity of mast cells in tongue from five different avian species

This study was conducted with the aim of determining the morphology, distribution and heterogeneity of mast cells in the tongues of seagull (Larus fuscus), common buzzard (Buteo buteo), goose (Anser anser), white stork (Ciconia ciconia) and Gerze rooster. The study used five samples of tongue material from each of the healthy adult avian species. The samples were fixed in 10% neutral‐buffered formalin (NBF) solution, then, after routine tissue follow‐up, the samples blocked with paraplast. Cross‐sections with 5–6 μm of thickness were stained with the 0.5% toluidine blue and alcian blue/safranin O (AB/SO). In all five avian species, it was found that the mast cells were in different sizes and round, oval or spindle‐shaped based on their place of distribution. Mast cell numbers were determined in stained with toluidine blue, examined ×40 objectives in a 1 mm² area. It was observed that mast cell density in subepithelial lamina propria and microscopic papilla was higher in the tongues of all species. Mast cell distribution and heterogeneity varied through the tongue, and there were more mast cells in the dorsal side of the tongue than the ventral side. The highest amount of mast cells was found in the tongue of the Gerze rooster among all five species. In the tongue cross‐sections stained with the combined method of alcian blue/safranin O (AB/SO), the mast cells were stained as AB (+), SO (+) and AB/SO (+) (mixed).     

Localization of amylin‐like immunoreactivity in the striped velvet gecko pancreas

Immunohistochemical techniques were employed to investigate the distribution of amylin‐like immunoreactive cells in the pancreas of gecko Homopholis fasciata. Four types of endocrine cells were distinguished: insulin immunoreactive (B cells), pancreatic polypeptide immunoreactive (PP cells), glucagon and pancreatic polypeptide immunoreactive (A/PP cells) and somatostatin immunoreactive cells (D cells). Pancreatic islets contained B, A/PP and D cells, whereas extrainsular regions contained B, D and PP cells. In the pancreatic islets, amylin‐like immunoreactive cells corresponded to B cells, but not to A/PP or D cells. In the extrainsular regions, amylin‐like immunoreactive cells corresponded to either B or PP cells. Amylin secreted from intrainsular B cells may regulate pancreatic hormone secretion in an autocrine and/or a paracrine fashion. On the other hand, amylin secreted from extrainsular PP and B cells, and/or intrainsular B cells may participate in the modulation of calcium homoeostasis in an endocrine fashion.     

Cellular Composition of the Pancreatic Islets in Mongolian gerbils (Meriones unguiculatus)

In Mongolian gerbil, morphological changes with age in the content of endocrine cells in the pancreatic islets were analyzed and their relation evaluated by an oral glucose tolerance test. The glucose level 2 hours after glucose administration was 125 ± 5 mg./dl in the young group and 103 ± 4 mg./dl in the old group. In the dorsal portion, B cells were mainly observed in the central area of the islets, surrounded by circular layers of A cells in the peripheral area. Between the A cells and B cells, D cells were scattered or present in layers. A few PP cells were present in the peripheral area of the islets. In the ventral portion, only a few A cells were observed in the peripheral area of the islets, and B cells were surrounded by PP cells. Secretory granules of A cells generally had an electron-dense spherical core in the limiting membrane. The halo between the limiting membrane and core in A cells was narrower than that in B cells. Secretory granules of B cells were larger than those in A cells, and the core was less electron-dense, and the halo was wider. Secretory granules of D cells were similar in size to those of A cells; the core showed low electron density, and the halo was very narrow. Granules of PP cells resembled those of A cells, but the electron density of the core was slightly lower. The gerbils showed changes in glucose tolerance, the size of the pancreatic islets, the percentage of B cells, and of A cells in the dorsal portion with age. The content of endocrine cells in Mongolian gerbils was similar to that in humans, rats, mice, and hamsters.     

Secretion of inhibin in female Japanese quails (Coturnix japonica) from hatch to sexual maturity

To clarify the cellular source and secretory pattern of inhibin in the Japanese quail during follicular development, the plasma concentrations of immunoreactive (ir) inhibin were measured from 1 to 7 weeks after hatching. Localization of the inhibin/activin alpha, beta A and beta B subunits was investigated by immunohistochemistry. To monitor development of the pituitary and ovarian functions, the plasma luteinizing hormone (LH) and progesterone concentrations were also measured. Ovarian weight increased gradually until 6 weeks of age and then abruptly increased at 7 weeks of age just at the onset of egg production. Plasma concentrations of LH increased significantly at 6 weeks of age. The plasma concentrations of ir-inhibin and progesterone and the pituitary contents of LH also increased significantly at 7 weeks of age. Immunohistochemically, the inhibin/activin alpha, beta A and beta B subunits were localized in the granulosa cells of all follicles during different stages of development from 1 to 7 weeks after hatching. The inhibin alpha, beta A and beta B subunits were also found in the interstitial cells but not theca cells of all follicles. These results demonstrated that the plasma concentrations of ir-inhibin of the female Japanese quails rose with ovarian development. The immunohistochemical results suggested that granulosa and interstitial cells are the major source of ovarian inhibins in female Japanese quails.