No abstract available.
Nucleopolyhedrovirus* ; Sequence Analysis*

No abstract available.
Animals ; Cloning, Molecular* ; Interleukin-2* ; Mice*

Although replacement therapy with insulin can prevent acute metabolic disorder in patients with IDDM (insulin dependent diabetes mellitus), it does not permanently restore glucose homeostasis. Recently it has been reported that islet transplantation could completely correct the glucose metabolic abnormalities and prevent further progression of the secondary complications of IDDM. For successful transplantation, the isolated islets should be prepared without loss of viability, while their immunogenicity being suppressed to reduce graft rejection. The present study was aimed to determine the optimal condition of islet culture, and to transplant them into the digestive organs including gastroin-testinal wall and salivary gland. For islet culture, pancreatic islets were isolated by a modified collagenase digestion technique from rats and cultured for 24, 48 and 72 hours in RPMI-1640 containing 0, 5.6 and 16.7 mM glucose. The viability of islets was evaluated by detection of insulin mRNA expressed in islet beta-cells using the in-situ hybridization and northern blot analysis, while their insulin content was examined by immunocytochemistry. Insulin mRNA was significantly reduced after 48 hours of culture in the islets incubated with absence of glucose, while distinct immunoreaction for insulin remained in the same islet. On the other hand, the islets cultured with normoglycemic (5.6 mM glucose) and hyperglycemic (16.7 mM glucose) conditions showed a normal or excessive transcription of insulin gene after 72 hours, respectively. These results indicate that biosynthetic activity of islets could be maintained longer than 72 hours without alteration of viability when they were cultured in normoglycemic condition. Therefore, we used islets cultured for 72 hours with 5.6 mM glucose for transplantation. The islets were implanted into the submucosal wall of the stomach and duodenum as well as into the parenchyme of the submandibular gland of the streptozotocin-induced diabetic rats. The transplanted islets in the gastrointestinal wall were abolished in 72 hours, while the islets injected into the submandibular gland retained normal cellular structure with viability for longer period. The beta-cell in the submandibular gland showed similar immunoreactivity for insulin compared to that of normal islets. However, they showed gradual infiltration of lymphocytes and beta-cell destruction at 10~14 days after transplantation. We suggested that the submandibular gland could be recommended as an alternative site for islet transplantation, because it is very easy to access for transplantation and provides the structural and functional similarities to pancreas in which the islets spontaneously grow.
Animals ; Blotting, Northern ; Cellular Structures ; Collagenases ; Diabetes Mellitus, Type 1 ; Digestion ; Duodenum ; Glucose ; Graft Rejection ; Hand ; Homeostasis ; Humans ; Immunohistochemistry ; Insulin ; Islets of Langerhans ; Islets of Langerhans Transplantation ; Lymphocytes ; Pancreas ; Rats* ; RNA, Messenger ; Salivary Glands ; Stomach ; Submandibular Gland ; Transplantation

Recently nitric oxide (NO) is known as a bioactive molecule modulating secretory activity in various glandular tissues. Previously we have localized bNOS, a neuronal isoform of nitric oxide synthase, in the pancreatic tissue, particularly in the pancreatic islet of Langerhans and in the neurons of intrapancreatic ganglia. It implies that NO may play the important roles in regulation of pancreatic secretion by transmitting the neuronal signals from autonomic nervous system to endocrine and/or exocrine system of pancreas. We also revealed that NO is involved in regulation of insulin secretion and its synthesis. The present study was designed to elucidate the regulatory effect of NO on the pancreatic exocrine secretion by way of insulo-acinar axis. For the experiment, we observed modification of amylase secretion in the rats treated with N(G)-nitro-L-arginine-methyl ester (NAME), a potent NOS inhibitor. In addition, we observed the expression of clusterin which is known to be a protein associated with cell viability in order to assess the cytotoxic effect of NO. The present study showed that the intra-pancreatic NO is involved in regulation of amylase secretion of pancreatic acinar cells. Amylase immunoreactivity was significantly decreased at 60 and 90 min after NAME injection, although little change was seen during 30 min after treatment. However, the amylase immunoreaction was recovered toward the normal range at 120 min after NAME treatment. In electron-immunolabeling experiment, we observed the secretory granules with higher electron density, but less immunolabeling for amylase at 60~90 min after NAME treatment, while they restored normal feature and labeling density at 120 min. Clusterin expression increased along with the time course of experiment and demonstrated a highest level at 120 min after NAME injection. Taken together, the above results indicate that lowered level of NO induced by NAME treatment reduces amylase secretion of acinar tissue. It implies that increased level of NO in physiological range may stimulate pancreatic exocrine secretion.
Acinar Cells ; Amylases ; Animals ; Autonomic Nervous System ; Axis, Cervical Vertebra ; Cell Survival ; Clusterin ; Ganglia ; Insulin ; Islets of Langerhans ; Neurons ; Nitric Oxide Synthase ; Nitric Oxide* ; Pancreas ; Rats ; Reference Values ; Secretory Vesicles

Stem cells in adult pancreas and their specific marker are poorly characterized. We hypothesized that pancreatic stem cells could evolve from the duct system in response to neogenic stimulation. Following partial pancreatectomy (Px), we found extensive formation of ductules consisting of nestin-positive epithelial cells with higher replicating ability in the neogenic foci after Px. The neogenic ductules were isolated for the culture of nestin-positive duct cells. These nestinpositive duct cells were numerous and displayed extensive self-replication in the duct cell explants, thus depicted as nestin-positive duct stem (NPDS) cells. Endocrine cells, mostly insulin cells were present in the explants at day 2 as single cells or as small clusters adjacent to the NPDS cells, and formed islet-like masses at day 3 of culture, implying islet cell differentiation from NPDS cells. We found transient up-regulation of PDX-1 expression by RT-PCR at day 3 after Px in pancreatic tissue. We investigated the effect of clusterin overexpression on differentiation of insulin beta cells from duct cells We found that the number of insulin producing cells increased 11.5 fold when clusterin was overexpressed. Insulin expression, both insulin mRNA and peptide levels, was increased in clusterin cDNA transfected cells. In conclusion, we suggest that NPDS cells could be generated from adult pancreas by neogenic motivations and they may differentiate into insulin-secreting-cells, and clusterin could stimulate not only differentiation of precursor cells in the pancreatic duct, but also proliferation of predifferentiated beta cells. Those differentiated beta cells are functional cells secreting insulin in response to glucose stimulation.
Adult* ; Cell Differentiation* ; Clusterin ; DNA, Complementary ; Endocrine Cells ; Epithelial Cells ; Glucose ; Humans ; Insulin ; Islets of Langerhans ; Nestin ; Pancreas* ; Pancreatectomy ; Pancreatic Ducts ; RNA, Messenger ; Stem Cells* ; Up-Regulation

Interactions among dexamethasone, dehydroepiandrosterone (DHEA), lipopolysaccharide (LPS), and antimycin A on the glutamate uptake and the polyamine uptake were investigated in primary cultures of rat cerebral cortical astrocytes to examine the effects of dexamethasone and DHEA on the regulatory role of astrocytes in conditions of increased extracellular concentrations of glutamate or polyamines. 1. (3H)Glutamate uptake: LPS and antimycin A decreased Vmax, but both drugs had little effect on Km. Dexamethasone also decreased basal Vmax without any significant effect on Km. And dexamethasone further decreased the antimycin A-induced decrease of Vmax. DHEA did not affect the kinetics of basal glutamate uptake and the change by LPS or antimycin A. 2. (14C)Putrescine uptake: LPS increased Vmax, and antimycin A decreased Vmax. They showed little effect on Km. Dexamethasone decreased Vmax of basal uptake and further decreased the antimycin A-induced decrease of Vmax, and also decreased Vmax to less than control in LPS-treated astrocytes. DHEA did not affect Km and the change of Vmax by LPS or antimycin A. 3. (14C)Spermine uptake: Antimycin A decreased Vmax, and LPS might increase Vmax. Km was little affected by the drugs. Dexamethasone decreased basal Vmax and might further decrease the antimycin A-induced decrease of Vmax. And dexamethasone also decreased Vmax to less than control in LPS-treated astrocytes. DHEA might increase basal Vmax and Vmax of LPS-treated astrocytes. 4. Vmax of glutamate uptake by astrocytes was increased by putrescine (1000 muM & 2000 muM) and spermidine (200 muM, 500 muM & 2000 muM). Spermine, 200 muM (and 100 muM), also increased Vmax, but a higher dose of 2000 muM decreased Vmax. Km of glutamate uptake was not significantly changed by these polyamines, except that higher doses of spermine showed tendency to decrease Km of glutamate uptake. In astrocytes, dexamethasone inhibited the glutamate uptake and the polyamine uptake in normal or hypoxic conditions, and the polyamine uptake might be stimulated by LPS and DHEA. Polyamines could aid astrocytes to uptake glutamate.
Animals ; Antimycin A* ; Astrocytes* ; Dehydroepiandrosterone* ; Dexamethasone* ; Glutamic Acid* ; Kinetics ; Polyamines ; Putrescine ; Rats* ; Spermidine ; Spermine

The present study was performed to corroborate our hypothesis that soybean diet or SBTI treatment could stimulate neogenic regeneration of pancreatic beta cells, but also increase insulin synthesis and secretion from the beta cells for correction of hyperglycemia and diabetic symptoms. We, thus, monitored the beta cell regeneration in the neogenic pancreas as well as the changes of the blood glucose and insulin levels after subtotal pancreatectomy. The diabetic animals with hyperglycemia induced by the subtotal pancreatectomy showed recovery of blood glucose level toward the normal range (<150 mg/dl) by giving raw soybean for 3~4 weeks. Most animals treated with SBTI remained in euglycemic condition in spite of diabetic induction by subtotal pancreatectomy. Their serum insulin level was also recovered to the level of normal control, indicating the increased insulin synthesis and secretion from the neogenic beta cells. Neogenic area was enlarged at least 2 times in the pancreatectomized rats with dietary soybean or SBTI treatment, when compared with their pancreatectomized controls without any dietary treatment. In neogenic tissue, few endocrine cells were detected as a single cell or cell cluster at 3 days, and they formed primitive islet at 7 days after pancreatectomy in non-treated controls. The numbers of beta cells as well as alpha cells were considerably increased in the SBTI treated rats, and early formation of primitive islets were found in the neogenic tissue of those animals at 3 days after pancreatectomy. Those beta cells demonstrated a strong immunoreactivity for insulin, indicating their bioactive insulin secretion. Clusterin, a marker protein for pancreatic neogenesis, was expressed in the wider pancreatic area and at earlier stage after pancreatectomy when compared with non-treated control rats, indicating acceleration and stimulation of neogenesis of pancreas by stimulating proliferation and differentiation of the functional pancreatic cells. Taken together, we concluded that dietary soybean and SBTI could stimulate beta cell neogenesis and induce activation of insulin synthesis and secretion from the neogenic beta cells for correction of glucose homeostasis in diabetic subjects.
Acceleration ; Animals ; Blood Glucose ; Clusterin ; Diet* ; Endocrine Cells ; Glucose ; Homeostasis ; Hyperglycemia ; Insulin ; Insulin-Secreting Cells ; Pancreas ; Pancreatectomy* ; Rats ; Reference Values ; Regeneration ; Soybeans* ; Trypsin*

Human SIRT1 controls various physiological responses including cell fate, stress, and aging, through deacetylation of its specific substrate protein. In processing DNA damage signaling, SIRT1 attenuates a cellular apoptotic response by deacetylation of p53 tumor suppressor. The present study shows that, upon exposure to radiation, SIRT1 could enhance DNA repair capacity and deacetylation of repair protein Ku70. Ectopically over-expressed SIRT1 resulted in the increase of repair of DNA strand breakages produced by radiation. On the other hand, repression of endogenous SIRT1 expression by SIRT1 siRNA led to the decrease of this repair activity, indicating that SIRT1 can regulate DNA repair capacity of cells with DNA strand breaks. In addition, we found that SIRT1 physically complexed with repair protein Ku70, leading to subsequent deacetylation. The dominant-negative SIRT1, a catalytically inactive form, did not induce deacetylation of Ku70 protein as well as increase of DNA repair capacity. These observations suggest that SIRT1 modulates DNA repair activity, which could be regulated by the acetylation status of repair protein Ku70 following DNA damage.
Sirtuins/genetics/*metabolism ; RNA, Small Interfering/genetics ; Humans ; DNA-Binding Proteins/*metabolism ; DNA Repair/*genetics ; DNA/*genetics ; Cell Line ; Antigens, Nuclear/*metabolism ; Acetylation

OBJECTIVES: Infection and replication of the hepatitis B virus are closely related to the host immunity. Anticancer chemotherapy decreases the immune response of the host, Especially, glucocorticoid can activate the replication of hepatitis B virus directly. It is well known that hepatitis B virus infection and hepatic complications are more common in patients with hematologic malignancies like malignant lymphoma. We studied the incidence of hepatitis B virus infection and hepatic complications following anti-cancer chemotherapy in patients with malignant lymphoma. METHODS: Among 224 cases diagnosed as malignant lymphoma from January 1989 to December 1993 at Yonsei University Medical Center, 77 cases tested for hepatitis B virus serology was studied. RESULTS: 1) Eighteen cases (23%) was HBsAg positive. 2) The results of hepatitis C virus serology in six cases were all negative. 3) Eight (57%) of 14 follow-up cases had hepatic complications, Two patients had fulminant hepatitis, two nonicteric hepatitis and four icteric hepatitis. 4) Interferon-alpha was administered in three cases among the patients with hepatic complications. Loss of HBeAg was observed in one case and loss of HBsAg in another case. CONCLUSION: Serious hepatic complications can be occurred following anticancer chemotherapy in HBsAg-positive patients with malignant lymphoma. Therefore, we recommend that patients being considered as candidates for anticancer chemotherapy should routinely undergo serologic test for Hepatitis B virus. In addition HBsAg-positive patients with anticancer chemotherapy should be regularly monitored for hepatic injury. And with the careful use of steroid and interferon, prolongation of survival might be searched for these patients.
Academic Medical Centers ; Drug Therapy* ; Follow-Up Studies ; Hematologic Neoplasms ; Hepacivirus ; Hepatitis ; Hepatitis B ; Hepatitis B e Antigens ; Hepatitis B Surface Antigens* ; Hepatitis B virus ; Humans ; Incidence ; Interferon-alpha ; Interferons ; Lymphoma* ; Serologic Tests

Our previous works have shown that human thyroid follicular cells from Graves' disease and FRTL-5 rat thyroid cells express the intercellular adhesion molecule-1 (ICAM-1) molecule and its expression is upregulated by several cytokines, interferon-gamma, tumor necrosis factor-alpha, interleukin-1 beta and interleukin-6. We used FRTL-5 cells which show hormonal dependence of growth and function for the study of hormonal regulation of ICAM-1 gene, We studied ICAM-1 mRNA expression and promoter regulation after cloning of rat ICAM-1 promoter. We found very interesting findings that thyroid stimulating hormone (TSH) and forskolin downregulates steady state MHC class land ICAM-1 mRNA levels in FRTL-5 cells; furthermore, TSH/cAMP inhibit cytokines (interferon-gamma,tumor necrosis factor-alpha)-mediated maximal ICAM-1 mRNA expression, In addition, hydrocortisone and insulin differentially regulate the ICAM-1 mRNA levels; hydrocortisone markedly suppresses the mRNA level but insulin partially recovers hydrocortisone mediated ICAM-1 suppression, The interferon-gamma and tumor necrosis factor-alpha increases full ICAM-1 promoter (pCAM-1822) activity and this cytokine mediated increase of the promoter activity is also inhibited by TSH and forskolin, Thus TSH/cAMP pathways play roles as a antagonistic action for maximal expression of ICAM-1 gene by these cytokines. We propose this TSH action is one of physiologic mechanisms to preserve self tolerance in face of abnormal cytokine challenges in systemic inflammatory condition or acute phase response.
Animals ; Clone Cells ; Cloning, Organism ; Colforsin ; Cytokines ; Gene Expression* ; Graves Disease ; Humans ; Hydrocortisone ; Insulin ; Intercellular Adhesion Molecule-1* ; Interferon-gamma ; Interleukin-1beta ; Interleukin-6 ; Necrosis ; Rats ; RNA, Messenger ; Self Tolerance ; Thyroid Gland* ; Thyrotropin ; Tumor Necrosis Factor-alpha