Effect of age onAgaricus bisporus PHA-B stimulated insulin release and45Ca2+ uptakein vitro by islets of langerhans

Summary Thein vitro basal insulin release and⁴⁵Ca²⁺ uptake by rat islets of Langerhans remain unaffected by the animal’s age. However, whenAgaricus bisporus lectin PHA-B is added to the medium, there is a significant stimulation of basal insulin secretion and⁴⁵Ca²⁺ uptake. The islets isolated from younger rats are more sensitive toA. bisporus PHA-B stimulation and register 1.5-fold and 3-fold more increases of insulin release and⁴⁵Ca²⁺ uptake respectively as compared to islets isolated from 12-month-old rats. Age-related conformational changes in the B-cell membrane are suggested as a possible explanation for the above observation. CDRI Communication No. 3428     

Recherches histologiques et histochimiques des îlots de langerhans du pancréas du porc

Résumé Les cordons de cellules A et B dans les îlots de Langerhans du porc sont entremêlés les uns avec les autres. Les cellules B en comparaison avec les cellules A montrent une activité beaucoup plus importante pour beaucoup d'enzymes comme pour la G-6-Pase, G-6-PDH, ATPase, ICDH et pour la phosphatase acide. La réaction polychromatique avec pseudoysocianine est positive uniquement dans les cellules B. Dans ces cellules on détecte également une quantité importante de zinc et de phospholipides.

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Summary The A and B cell cords of porcine islets of Langerhans are intertwined with one another. The B cells exhibit far more intense activity than the A cells for many enzymes, including G-6-Pase, G-6-PDH, ATPase, ICDH and acid phosphatase. The polychromatic pseudoisocyanine reaction is positive only in B cells. These cells also contain a large quantity of zinc and phospholipids.

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Zusammenfassung Die A- und B-Zellenstränge der Langerhansschen Inseln des Schweinepankreas sind miteinander verschlungen. Für viele Enzyme zeigen die B-Zellen eine weit intensivere Aktivität als die A-Zellen. Zu diesen Enzymen gehören G-6-Pase, G-6-PDH, ATPase, ICDG und saure Phosphatase. Die polychromatische Pseudoisozyanin Reaktion ist nur in B-Zellen positiv. Diese Zellen enthalten ausserdem grosse Mengen von Zink und Phospholipiden.

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Resumen Se han entremezclado los cordones de células A y B de las islas de Langerhans del cerdo. Comparando las células B, con las A vemos que las B presentan una actividad mucho más importante para numerosas enzimas tales como la G-6-Pase, G-6-PDH, ATPase, ICDH y para las fosfatasas ácidas. La reacción policromática con pseudoisocianina es positiva sólo para las células B. En dichas células se observa también una cantidad importante de cinc y de fosfolípidos.

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Riassunto I cordoni delle cellule alfa e beta delle isole di Langerhans del maiale si intrecciano gli uni agli altri. In rapporto alle cellule alfa, quelle beta presentano, per alcuni enzimi quali la G-6-Pasi, G-6-PDH, la ATPasi, ICDH e la fosfatasi alcalina, una attività molto più intensa. La reazione policromatica con pseudoisocianina risulta positiva esclusivamente nelle cellule beta, nelle quali si rilevano altresì notevoli quantità di zinco e di fosfolipidi.

     

Anatomo-clinical correlations in amyloidosis of the islets of langerhans

Summary After discussing previous publications on the subject, the authors describe 25 cases of amyloid disease of the islets of Langerhans. They come to the conclusion that two factors,i.e. diabetes mellitus and aging, are responsible for pancreatic amyloidosis.     

Transplantation of isologous islets of langerhans in diabetic rats

Summary Isologous isolated islets of Langerhans were transplanted into the peritoneum and, via the portal vein, into the liver of diabetic rats. In both groups almost normal blood glucose and serum insulin levels were achieved for a period of three months. Glucose tolerance tests were markedly improved. Morphological examination of the transplanted islets and immunohistochemical tests for insulin and glucagon showed the liver to be a more suitable site for islet grafting than the peritoneum.     

Transplantation of isologous islets of langerhans in diabetic rats. Long-term immunohistochemical results

Summary Isologous isolated islets of Langerhans were transplanted into the peritoneum and through the portal vein into the liver of diabetic rats. This resulted in the normalization of fasting blood glucose levels, with clear improvement of glucose tolerance tests. The results after intrahepatic implantation were better than after intraperitoneal implantation. Three months after implantation of islets into the peritoneum diabetes recurred and after one year only 2 of the 15 rats were alive, with high blood glucose levels. In the group with intrahepatic islets the normalization of blood glucose was maintained over a period of one year. Immunohistochemical insulin proofs were positive in the peritoneum over a period of 3 months and in the liver up to one year after implantation. Glucagon proofs were positive in the intraperitoneal islets for 6 weeks and in intrahepatic ones for one year. Morphological examination of transplanted islets suggested that the liver is better suited for islet transplantation than the peritoneum. The investigations were carried out in connection with and with the generous aid of the Research Project‘Diabetes mellitus und Fettstoffwechselst?rungen’, MfGe, DDR.     

Secretion in the B-cells of islets of langerhans as demonstrated by zinc staining

Summary Intact islets of Langerhans were isolated from Wistar rats by means of vital fixation, microdissection and development of the metal sulfides formed with Timms reagent. In such intact islets, the β-granules and the cell organelles can be shown up well electron microscopically. The endocrine pancreas tissue of normal rats contains a relatively constant average of 175 densely structured granules per 100 μm². After administration of sulfonylurea, the number of (less dense) granules is reduced to 125 (in adipose animals 115) granules per 100 μm². Besides empty ‘sacs’, large-vesicle Golgi apparatus and ballooned forms of the endoplasmic reticulum occur.     

Long-term effects of glibenclamide on the insulin production,oxidative metabolism and quantitative ultrastructure of mouse pancreatic islets maintained in tissue culture at different glucose concentrations

Summary In order to evaluate long-term effects of sulphonylureas on pancreatic islet structure and function, isolated mouse islets were maintained in tissue culture for one week at various glucose concentrations, and in the absence or presence of glibenclamide. When the islets were cultured at 3.3 or 5.5 mmol/1, but not at 16.7 mmol/1 glucose, it was found that the drug stimulated insulin secretion into the culture medium during the initial 3 days of culture. During the remainder of the culture period no such enhancement of secretion was demonstrated. Insulin release due to glibenclamide apparently resulted in rapid depletion of intracellular insulin stores. The finding of an enlarged B-cell Golgi apparatus in the drug-treated islets was probably associated with granule discharge. The failure of glibenclamide to promote insulin secretion during the whole culture period could reflect the adverse effects of the drug on islet insulin biosynthesis as indicated by short-term experiments performed after culture. Similar experiments showed that the impaired insulin biosynthesis could not be restored by withdrawal of the drug from the culture medium for 3 days. Furthermore, the capacity for insulin release in response to an acute glucose challenge at the end of the culture period, was abolished by culture in the presence of glibenclamide. The drug effects on insulin biosynthesis and intracellular insulin stores, which were most pronounced at 5.5 mmol/1 glucose, possibly resulted from changes in B-cell metabolism as suggested by the diminished islet glucose-oxidation rate. The spatial characteristics of islet mitochondria indicated that these changes might involve an adaptation to substrates other than glucose. In conclusion, our findings suggest that sulphonylureas have an insulinotropic effect, which is however transient. Indeed, it rather seems as if long-term exposure of islet B-cells to sulphonylureasin vitro were accompanied by functional deficiency.     

Adult islets cultured in collagen gel transdifferentiate into duct-like cells

AIM: To establish a model of islet-ductal cell transdifferen-tiation to identify the transdifferentiated cells. METHODS: Collagen was extracted from rat tail at first. Purified rat islets were divided into three groups, embedded in collagen gel and incubated respectively in DMEM/F12 alone (control group), DMEM/F12 plus epidermal growth factor (EGF), DMEM/F12 plus EGF and cholera toxin (CT). Transdifferentiation was proved by microscopy, RT-PCR, immunohistochemistry and RIA. RESULTS: Islets embedded in collagen gel plus EGF and CT were cystically transformed and could express new gene cytokeratin 19 while still maintaining the expression of insulin and Pdx-1 genes. Immunohistochemistry demonstrated that the protein of cytokeratin 19 was only expressed in the third group. The insulin content secreted by islets in the third group decreased significantly during the transdiffe-rentiation. CONCLUSION: CT is a crucial factor for the islet-ductal cell transdifferentiation.     

Effect of alloxan on β-cells of islets of langerhans in the albino rat

Summary 1) The diabetogenic dose of alloxan for the albino rat is 150 mg/kg body weight, given in a single dose, subcutaneously. 2) When one third of the diabetogenic dose is employed, albino rats fail to develop diabetes and the pancreatic islet tissue does not show any change revealed by light microscopy. 3) Administration of subdiabetogenic doses of alloxan concurrently with glucose, ACTH or anterior pituitary extract results in structural changes in the pancreatic islet tissue which are reflected by changes in the blood-sugar levels. 4) The histological changes observed in the islet tissue of the pancreases are: degranulation, hyaline degeneration, «hydropic» changes and necrosis. «Hydropic» changes are found to be due to glycogen infiltration of the cells.

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Zusammenfassung 1) Die diabetogene Alloxan-Dosis fuer die Albinoratte betraegt 150 mg/kg in Einzeldosis auf subkutanem Weg. 2) Wenn man ein Drittel der diabetogenen Dosis verwendet, offenbaren die Albinoratten keinen Diabetes und das inselpankreatische Gewebe zeigt keine mit dem optischen Mikroskop erfassbare Veraenderung. 3) Die Verabreichung von subdiabetogenen Alloxan-Dosen, zusammen mit Glukose, ACTH oder Hypophysenvorderlappen-Extrakt bewirkt strukturelle Veraenderungen im Pankreas-Inselgewebe, die ihren Widerhall in Blutzuckerschwankungen finden. 4) Die im Pankreas-Inselgewebe beobachteten histologischen Veraenderungen sind: Degranulierung, hyaline Degeneration, «hydropische» Veraenderungen und Nekrosen. Die «hydropischen» Veraenderungen werden durch die Glykogen-Infiltration in die Zellen verursacht.

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Resumen 1) La dosis diabetógena de aloxana para la rata albina es de 150 mg/kg, suministrados en dosis única por vía subcutánea. 2) Cuando se emplea la tercera parte de la dosis diabetógena, las ratas albinas no desarrollan la diábetes y el tejido ínsulo-pancreático no presenta ninguna alteración apreciable al microscopio óptico. 3) La suministración de dosis sub-diabetógenas de aloxana, conjuntamente con la glucosa, el ACTH o el extracto de antehipófisis, produce alteraciones de la estructura en el tejido de las islas del páncreas: dichas alteraciones se evidencian con las variaciones de la glucemia. 4) Las alteraciones histológicas observadas en el tejido insular del páncreas son las siguientes: degranulación, degeneración hialina, alteraciones «hidrópicas» y necrosis. Las alteraciones «hidrópicas» son consecuencia de infiltración de glúcogeno en las células.

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Resume 1) La dose diabétogène de alloxane pour le rat albinos est de 150 mg/kg administrée dans une seule dose par voie subcutanée. 2) En employant un tiers de la dose diabétogène, les rats albinos ne développent pas le diabète et le tissue insulo-pancréatique ne présente pas des altérations relevables au microscope optique. 3) L'administration de doses subdiabétogènes de alloxane, avec du glucose, ACTH ou extrait de antéhypophyse, provoque des altérations dans le tissue des îles du pancréas avec des variations de la glycémie. 4) Les altérations histologiques observées dans le tissue insulaire du pancréas sont: dégranulation, dégénération jaline, altérations «hydropiques» et nécrose. Les altérations «hydropiques» sont dues à l'infiltration du glycogène dans les cellules.

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Riassunto 1) La dose diabetogena di allossana per il ratto albino è di 150 mg/kg somministrati in una dose singola per via sottocutanea. 2) Quando si impiega un terzo della dose diabetogena, i ratti albini non sviluppano il diabete ed il tessuto insulopancreatico non presenta alcuna alterazione rilevabile al microscopio ottico. 3) La somministrazione di dosi subdiabetogene di allossana, in concomitanza con il glucosio, l'ACTH o l'estratto di anteipofisi, determina alterazioni strutturali nel tessuto delle isole del pancreas che sono riflesse da variazioni della glicemia. 4) Le alterazioni istologiche osservate nel tessuto insulare del pancreas sono: degranulazione, degenerazione jalina, alterazioni «idropiche» e necrosi. Le alterazioni «idropiche» sono dovute all'infiltrazione del glicogeno nelle cellule.

     

Insulinotropic action of L-rhamnose in isolated rat islets

Summary L-Rhamnose at different concentrations stimulated incorporation of³H-leucine both into islet (pro)insulin and that released into the medium. Maximum isotope incorporation with either glucose or rhamnose was seen at a concentration of 16.7 mM, although the glucose-induced effect was significantly greater. Like glucose, rhamnose also enhanced the activities of acid phosphatase and cathepsin B in isolated rat islets.Communication No. 2759.     

胎鼠胰腺干细胞体外对胰岛的保护作用观察

目的观察胎鼠胰腺干细胞体外对胰岛功能的保护作用。方法将孕16d的sD大鼠胎鼠胰腺干细胞分离、纯化、培养传代,免疫细胞化学法及流式细胞术鉴定;分离纯化sD大鼠胰岛,双硫腙鉴定后分为A组和B组,分别行单纯胰岛培养及胰岛与胰腺干细胞联合培养14d,期间观察胰岛形态变化、检测胰岛存活率及细胞凋亡率,ELISA法检测胰岛素分泌量、计算刺激指数。取两组培养7d后悬浮生长的胰岛移植入糖尿病大鼠左肾包膜下,术后每天尾静脉采血以快速血糖测试仪检测血糖。结果胎鼠胰腺干细胞培养传代3代后免疫细胞化学可见巢蛋白（Nestin）阳性细胞,流式细胞术测定其含量占74．1％;培养第7、14天时B组胰岛存活率显著高于A组（P均〈0．01）,培养第7天时B组胰岛细胞凋亡率显著低于A组（P〈0．05）;培养第7、14天时B组高糖刺激后胰岛素分泌量及刺激指数均显著高于A组（P均〈0．01）;B组移植后大鼠血糖第5天降至正常。结论胎鼠胰腺干细胞与胰岛联合培养可明显延长胰岛体外存活时间并使其保持良好的活性。     

Flow cytometric analysis of DNA content in colorectal carcinoma

Over the past decade, flow cytometric DNA analysis has been employed by a number of investigators in an attempt to further define patient prognosis beyond classic pathologic staging. The results of these studies taken independently have been confusing; however, their cumulative effect suggests that flow cytometry is a useful prognostic indicator and can be used to further delineate prognosis within a specific pathologic stage. DNA nondiploid tumors are more likely to recur than diploid tumors, and patients with DNA nondiploid tumors have a poorer five-year survival than patients with DNA diploid tumors. There appears to be a weak relationship between advanced pathologic stage and DNA aneuploid tumors, although there is no clear and consistent relationship between tumor ploidy and histology. Therefore, all patients with colorectal tumors should undergo DNA ploidy analysis. Patients with DNA nondiploid tumors should be treated for biologically more aggressive disease independent of other prognostic variables. Ploidy status should be employed as a variable by which to randomize patients to both primary treatment schemes and adjuvant therapies in clinical trials.     

干细胞诱导分化为胰岛的研究进展

胰岛移植是治疗糖尿病的有效方法之一。本文复习了从胚胎干细胞和成体干细胞诱导分化为胰岛的研究进展 ,希望这方面的突破为糖尿病的治疗提供新的方法。     

DNA ploidy pattern in rectal carcinoid tumors

The nuclear DNA pattern of 22 rectal carcinoids was determined by cytophotometry of paraffin embedded tissues. The results were compared with clinical as well as histopathologic features of the tumor. Three of the carcinoids with synchronous or metachronous metastasis had aneuploid DNA pattern, whereas 19 tumors with no metastasis showed diploid DNA pattern. No other single clinical or pathologic feature of the tumor could predict more accurately the malignant potential and the subsequent course of the rectal carcinoid. It is concluded that DNA aneuploidy in rectal carcinoid tumors is not so rare as indicated by earlier studies and that it is a factor of significant prognostic value.Dr. George Tsioulias is a recipient of the Monbusho Scholarship (Japanese Ministry of Education).     

The effects of cyproheptadine on glucose tolerance and pancreatic islets in rats

Summary The effects of cyproheptadine (CPH) on plasma levels, of glucose, insulin and glucagon were studied in rats in order to clarify the diabetogenicity of this compound. CPH was given to the rats at a daily dose of 45 mg per kg body weight via gastric intubation for up to 20 days. Glucose intolerance appeared after 5 days of CPH treatment without significant increase in fasting glucose level. Plasma insulin response to glucose loading was depressed in the early phase of the glucose tolerance test in groups treated for 10 and 20 days. In these groups the insulinogenic index was significantly lowered. Pancreatic insulin content decreased rapidly after single dose of CPH. Plasma level and pancreatic content of glucagon were not changed by this compound. These results suggested that chronic treatment with CPH caused glucose intolerance in rats through its direct influence on pancreatic B-cell function.     

瘦素对离体大鼠胰岛分泌胰岛素的双向影响

目的 了解不同浓度的瘦素，在不同条件下对离体大鼠胰岛分泌胰岛素的影响。方法 利用细胞培养技术，在不同的葡萄糖浓度（5.6mmol/L或16.7mmol/L）和不同作用时间（10min或2h)下，以0,1,5,10,15,50ak 100μg/L瘦素作用大鼠胰岛，观察其对胰岛素分泌的影响；用放免法检测培养物上清液胰岛素浓度。结果 培养液葡萄糖浓度为5.6mmol/L，培养10min，1μg/L、5μg/L瘦素促进被孵育的胰岛的胰岛素分泌；培养2h,5μg/L瘦素促进基础胰岛素分泌，≥50μg/L瘦素抑制胰岛素分泌。葡萄糖浓度为16.7mmol/L，培养10min，≥50μg/L瘦素抑制胰岛素分泌；培养2h，≥5μg/L瘦素抑制胰岛素分泌。结论 重组瘦素对离体大鼠胰岛分泌胰岛素具有双向作用，并受瘦素浓度、作用时间和环境葡萄糖浓度等因素变化的影响。     

Effect of age on the binding of lectin125I-PHA-B to pancreatic islets of ratin vitro and stimulation of some cellular events

Summary Agaricus bisporus lectin (PHA-B) stimulates insulin releasein vitro. The stimulation is associated with increased conversion of proinsulin to insulin in the isolated islets of Langerhans of rats. Both these functions are directly proportional to the binding of I¹²⁵ PHA-B, which is more marked in the islets from younger rats. The lectin binding to islets is not affected by glucose concentration in the medium. C.D.R.I. Communication N ^o 4334.     

A method for enzymatic dissociation of cells from isolated pancreatic islets

Summary An enzymatic method for isolation of single cells from the islets of Langerhans is described. The isolated cells appeared well preserved and survived for at least 7 days when maintained in culture. The dry mass of the isolated islet cells was found to be decreased 30 min after administration of alloxan to obese-hyperglycemic mice. Isolated individual islet cells from obese-hyperglycemic mice had a higher dry mass than those from their lean litter mates. Traduzione a cura di G. U.     

DNA repair systems in early and persistent hepatocyte nodules in the rat

Summary The repair of three DNA lesions, namelyO ⁶-methylguanine, 7-methylguanine, and 3-methyladenine, was investigated within early and persistent hepatocyte nodules generated in Fischer 344 rats by a modified Solt-Farber procedure (diethylnitrosamine initiation followed by a 2-acetylaminofluorene/CCl₄ cycle). TheO ⁶-methylguanine-DNA methyltransferase concentration within both hepatocyte nodule types was always higher than that found in age-matched controls (normal, initiated-only and promoted-only livers). As far as 3-methyladenine and 7-methylguanine-DNA glycosylases are concerned, the early hepatocyte nodules showed far higher activities for both enzymes than were found in the controls, whereas in the persistent ones they underwent a significant decrease. In conclusion hepatocyte nodules are endowed with a high DNA repair activity, which is partly adaptive, partly constitutive; along with others, such a defence mechanism could allow transformed cells to resist many cytotoxic drugs.     

CD40 activation in human pancreatic islets and ductal cells

AIMS/HYPOTHESIS: CD40 expression on non-haematopoietic cells is linked to inflammation. We previously reported that CD40 is expressed on isolated human and non-human primate islets and its activation results in secretion of IL-8, macrophage inflammatory protein 1-beta (MIP-1beta) and monocyte chemoattractant protein-1 (MCP-1) through nuclear factor-kappaB and extracellularly regulated kinases 1/2 pathways. The objective of this study was to identify the pattern of gene expression, and to study viability and functionality affected by CD40-CD40 ligand (CD40L) interaction in human islets. Furthermore, we have studied the CD40-mediated cytokine/chemokine profile in pancreatic ductal cells, as they are always present in human islet transplant preparations and express CD40 constitutively. METHODS: CD40-CD40L gene expression modulation was studied by microarray on islet cells depleted of ductal cells. Selected genes were validated by quantitative RT-PCR. The cytokine profile in purified ductal cells was evaluated by Luminex technology, based on the use of fluorescent-coated beads, known as microspheres, and capable of multiplex detection of proteins from a single sample. Glucose-stimulated insulin secretion and islet viability were assessed by perifusion and 7-aminoactinomycin D membrane exclusion, respectively. RESULTS: Statistical analysis of microarrays identified 30 genes exhibiting at least a 2.5-fold increase across all replicate arrays. The majority of them were related to oxidative stress/inflammation. Prominently upregulated were chemokine C-X-C motif ligand 1 (CXCL1), CXCL2 and CXCL3 belonging to the CXC family of chemokines related to IL-8. CD40-mediated CXCL1 secretion was confirmed by ELISA. The viability or in vitro function was not affected by CD40 activation. In addition to previously reported IL-8, MIP-1beta and MCP-1, CD40 stimulation in ductal cells produced IL-1beta, IFN-gamma, TNF-alpha, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. CONCLUSIONS/INTERPRETATION: CD40 activation in islets and ductal cells produces cytokines/chemokines with a broad-spectrum range of biological functions.