Biomedical subjects

T Hirano

Publications and source records attributed to T Hirano.

At least 19 recordsLinked to original sources

PubMed1992

Human bone marrow stromal cell lines from myeloma and rheumatoid arthritis that can support murine pre-B cell growth.

In order to elucidate the pathologic significance of the bone marrow (BM) microenvironment in multiple myeloma (MM) and rheumatoid arthritis (RA), we established patient- or healthy donor (HD)-derived BM stromal cell lines by transfecting the plasmid for expression of SV40 large T Ag and examined their ability to support the stromal cell-dependent growth of a pre-B cell line, DW34. The means of recovered cell numbers of DW34 co-cultured with MM- and RA-derived BM stromal cell lines ranged from 6- to 10-fold more than those with HD-derived ones. Their enhanced ability to support DW34 cell growth was not caused by cytokines, including IL-6, IL-7, and c-kit ligand, although exogenous IL-7 could augment the growth-supporting ability. DW34 cell growth on the stromal cell lines was abolished by inhibiting cell-to-cell interaction with a membrane filter. FACS analysis revealed that the stromal cell lines did not express LFA-1 alpha, beta, NCAM, or ELAM-1. Both patient and HD BM stromal cell lines variably expressed ICAM-1, VCAM-1, and CD44. However, surface expression levels of these molecules did not correlate with the ability of the stromal cell lines to support DW34 cell growth. Taken together, these results suggested that BM microenvironment might play important roles in the pathogenesis of MM and RA.

Animals↗

PubMed1992

Circadian variation of [3H]dopamine handling in adrenal chromaffin cells of mice.

Circadian variation of exogenous [3H]dopamine handling by adrenal chromaffin cells was examined using mice habituated to 08.00-20.00 h light cycle. Experiments were carried out at 00.00, 06.00, 12.00 and 18.00 h. [3H]Dopamine-derived radioactivity reached a peak at 2 min then decreased rapidly except at 18.00 h, when no particular peak was observed at 2 min but at 30 min in both intact and denervated adrenals. In intact adrenals, the 2-min peak at 06.00 h was suppressed by corticosterone while in denervated adrenals the 2-min peak remained. The present result indicates that quick turnover of [3H]dopamine was suppressed by a steroid surge at about 2 h before light to dark alteration. Normal innervation is necessary for corticosterone-induced suppression.

Adrenal Glands↗

PubMed1992

Combined therapy of a cephalosporin, Shiomarin and a new potent protease inhibitor, E3123 in rat taurocholate-induced pancreatitis.

The role of infectious factors in the pathogenesis of acute pancreatitis and the protective effect of combined therapy with a new potent synthetic protease inhibitor, E3123, and a new potent synthetic cephalosporin, Shiomarin (SM) were examined in rat acute pancreatitis. Sodium taurocholate injection into the pancreatico-biliary duct of rats caused severe pancreatitis with a high mortality rate, characterized by hyperamylasemia, high amylase activity in ascitic fluid, and hyperendotoxemia and a high serum level of fibrin degradation products (FDP), redistribution of cathepsin B from the lysosomal fraction to the zymogen fraction. In rats with E3123 infusion almost all parameters were improved, including mortality rate, serum and ascitic fluid amylase levels, plasma endotoxin and serum FDP levels, and distribution of lysosomal enzyme. But combination therapy with E3123 and SM was significantly more protective than E3123 therapy alone. These results indicate that infection plays an important role in the development of severe pancreatitis and that combination therapy with a new synthetic protease inhibitor and a new potent antibiotic may be useful in the treatment of severe pancreatitis.

Acute Disease↗

PubMed1992

"Cocktail" therapy for acute pancreatitis: combined therapy of protease inhibitor, xanthine oxidase inhibitor and platelet activating factor antagonist in rat caerulein-induced pancreatis.

A supramaximal dose of caerulein (5 micrograms/kg.hr for 3.5 hours) caused an acute pancreatitis with marked hyperamylasemia and intense interstitial edema in rats. In this model of pancreatitis, the redistribution of lysosomal enzyme in acinar cells as well as the increased lysosomal and mitochondrial fragility were also observed. The combined therapy of a low molecular weight protease inhibitor, FOY, a synthetic platelet activating factor (PAF) antagonist, CV 6209, and a xanthine oxidase inhibitor, allopurinol produced more significant improvements in all the parameters examined than the therapy of any only one of these three agents, each only one therapy exerting a partial significant protective effect. These results indicate that several factors, such as unknown proteases activities, PAF and oxygen-derived free radicals may be involved in the pathogenesis of pancreatic injuries in this caerulein-induced pancreatitis. These results also suggest that such a combined therapy of different kinds of agents, whose therapeutic mechanisms are also different, is useful in the clinical treatment of acute pancreatitis.

Acute Disease↗

PubMed1992

Retinoic acid inhibits interleukin-6-induced macrophage differentiation and apoptosis in a murine hematopoietic cell line, Y6.

We established a radiation-induced murine hematopoietic cell line, Y6, that could be induced to differentiate into macrophages by interleukin-6 (IL-6). IL-6 also induced growth inhibition and apoptosis in Y6 cells. Retinoic acid (RA) inhibited such effects of IL-6 on Y6 cells. The inhibitory effect of RA on the effects of IL-6 was not caused by the downregulation of the IL-6 receptor, because RA neither affected the expression of IL-6 receptor mRNA nor the expression of IL-6 receptor molecule on the cell surface. Furthermore, RA did not inhibit the IL-6-induced expression of junB mRNA, indicating that the expression of functionally active IL-6 receptor and the signal transduction pathway activating the junB gene are not inhibited by RA. IL-6-induced macrophage differentiation of Y6 cells was preceded by the downregulation of the c-myc gene, which was also prevented by RA. Because the inhibitory effect of RA on Y6 cells was reversible and seemed not to require de novo protein synthesis, the RA receptor by itself might be directly involved in the inhibition of the IL-6 signal transduction pathway. The results indicated that the IL-6 signal transduction pathways leading to the induction of macrophage differentiation and junB gene expression can be dissected by RA.

Animals↗

PubMed1992

Hypertriglyceridemia is exacerbated by slow lipolysis of triacylglycerol-rich lipoproteins in fed but not fasted streptozotocin diabetic rats.

Hydrolysis by endothelial lipases of triacylglycerol-rich lipoproteins of diabetic origin were compared to lipoproteins of non-diabetic origin. The plasma lipoprotein fraction of density < 1.006 g/ml, including chylomicrons and VLDL, were incubated in vitro with post-heparin plasma (PHP) lipases. The lipoproteins of diabetic origin were hydrolysed at a significantly slower rate than lipoproteins from normal rats by the lipoprotein lipase component of PHP. However, if rats were fasted for 16 h prior to lipoprotein recovery, no differences in rates of VLDL hydrolysis were observed. Slower hydrolysis of lipoproteins of diabetic origin reflected a decrease in the apolipoprotein CII/CIII ratio and other changes in the apolipoprotein profile. To assess whether diabetic rats were less able to clear triacylglycerol independent of changes in the nature of the lipoproteins, we monitored the clearance of chylomicron-like lipid emulsions in hepatectomized rats. In vivo, emulsion triacylglycerol hydrolysis was not slowed due to diabetes. However, control and diabetic rats, which had been fasted for 16 h, cleared triacylglycerol at about twice the rate of fed rats. Triacylglycerol secretion rates in diabetic and control rats were similar, whether fed or fasted. We conclude that in streptozocin diabetic rats, hypertriglyceridemia was not due to overproduction of chylomicron- or VLDL-triacylglycerol, nor to decreased endothelial lipase activities. Rather, in fed diabetic rats, the triacylglycerol-rich lipoproteins are poorer substrates for lipoprotein lipase. This may lead to slower formation of remnants which would exacerbate slow remnant removal. VLDL of diabetic origin were hydrolysed as efficiently as VLDL from control donors, suggesting that in the fed state the lipolytic defect may be specific for chylomicrons.

Animals↗

PubMed1992

Changes in growth hormone and prolactin messenger ribonucleic acid levels during seawater adaptation of amago salmon (Oncorhynchus rhodurus).

To examine the changes in secretion of growth hormone (GH) and prolactin (PRL) with reference to their osmoregulatory roles, changes in pituitary mRNA levels and plasma concentrations of these hormones were examined during seawater adaptation in silvery juveniles (smolts) and precociously mature males (dark parr) of amago salmon (Oncorhynchus rhodurus). Transfer to seawater increased plasma sodium levels in both smolts and dark parr. Smolts adjusted their plasma sodium to the level associated with seawater-adaptation (165 mEq/liter) within 3 days, whereas no adjustment was seen in dark parr; the latter failed to survive in seawater for more than 3 days. In smolts, plasma GH levels increased significantly 1 day after transfer, whereas there was no significant change in dark parr. An increase in GH mRNA levels was observed in smolts in association with increased plasma GH, whereas there was no change in dark parr. In contrast, a reduction in plasma PRL levels was consistently observed in both smolts and dark parr after transfer to seawater. However, there was no significant change in PRL mRNA levels in either smolts or dark parr. These results suggest that both gene expression and release of GH are activated by seawater transfer only in smolts with adequate seawater adaptability, whereas PRL gene expression is decreased after seawater transfer regardless of seawater adaptability.

Adaptation, Physiological↗

PubMed1992

Effect of hypothermia on pancreatic acinar cells in rats.

This study was designed to evaluate the effects of direct pancreatic surface cooling on the exocrine pancreas. We measured the changes in serum amylase levels, pancreatic water, amylase and cathepsin B as a lysosomal enzyme, content, histological changes of acinar cells, and the subcellular distribution of cathepsin B after 1-2- and 3-hours of direct pancreatic cooling in rats. In addition, we evaluated the in-vivo amylase and cathepsin B output stimulated by caerulein, in-vitro lysosomal and mitochondrial fragility as well as the pancreatic adenylate energy metabolism. 2-hours cooling showed slight yet significant changes, but 3-hours cooling caused most significant changes including hyperamylasemia, increased pancreatic amylase content and very mild histological changes. Furthermore, 3-hours cooling caused a remarkable redistribution of cathepsin B activity from the lysosomal fraction to the heavier zymogen fraction, and colocalization of the lysosomal enzyme with the digestive enzyme, the impaired amylase and cathepsin B output into pancreatic juice stimulated by caerulein as well as the accelerated fragility of lysosomes and mitochondria, and impaired pancreatic adenylate energy metabolism. These results indicate the impaired exocrine pancreatic functions induced by direct pancreatic cooling injury induced by cooling as shown in the other models of experimental pancreatitis. Moreover, this cooling model of pancreatitis seems to be useful in understanding the early events in the pathogenesis of acute pancreatitis, and we must take these "cold" injuries of exocrine pancreas into considerations, particularly in the pancreas transplantation and in other major abdominal surgeries where the pancreas is exposed to cooling.

Amylases↗

PubMed1992

Fragility of subcellular organelles induced by pancreatic duct obstruction in rabbits.

The effects of short-term (6 hours) pancreatic duct obstruction on the possible secretion of lysosomal enzyme into pancreatic juice and subcellular lysosomal and mitochondrial fragility were investigated in rabbits. Caerulein stimulated the secretion of amylase and cathepsin B into pancreatic juice in controls. Blockage of the pancreatic duct for 6 hours caused a significant decrease of amylase and cathepsin B output into pancreatic juice, and a significant rise in portal serum amylase and cathepsin B levels, and pancreatic amylase content and an accelerated leakage of cathepsin B from lysosomes and malate dehydrogenase from mitochondria in in-vitro preparations, as well as redistribution of cathepsin B in acinar cells. These changes tended to continue for up to 12 hours after removal of the pancreatic duct obstruction. These results indicate that under physiological conditions, lysosomal enzymes are secreted into the pancreatic juice in response to stimulation by gut hormones and that increased lysosomal fragility, mitochondrial fragility and impaired pancreatic energy charge levels are closely related to the pathogenesis of pancreatic injury in this model. Moreover, zymogen colocalized with lysosomal enzyme after duct obstruction was secreted into pancreatic juice in increased amount together with digestive enzymes; these findings suggest that lysosomal enzymes play important pathophysiological roles in pancreatic juice.

Amylases↗

PubMed1992

Effect of short-termed pancreatico-biliary duct obstruction on lysosomal enzyme in rats: protective effect of a potent new protease inhibitor, E-3123.

To investigate the mechanism by which the pancreatic acinar cells are injured in animals with an obstructed common channel, we measured the amount of lysosomal enzymes and of amylase in the pancreatico-biliary juice in rats with pancreatico-biliary duct obstruction (PBDO). We tested the protective effect of a new potent synthetic protease inhibitor, E3123 (4-guanidinobenzoate methanesulfonate), on the exocrine pancreas in this model of PBDO and secretin infusion. Blockage of PBD for 4 hours and secretin (0.2 CU/kg.hr) infusion caused a significant rise in portal serum amylase and cathepsin B levels, pancreatic water content, and pancreatic amylase content, as well as redistribution of cathepsin B in acinar cells. These changes tended to continue for 12 hours after the removal of PBDO and disappeared at 24 hours. All the changes induced by PBDO with secretin infusion were no longer observed at 48 hours. The administration of 5 mg/kg.hr of E3123 during PBDO markedly attenuated all the parameters examined in this study. Thus, it had a significant protective effect on acinar cells in this model. E3123 in a dose of 2 mg/kg.hr had a partial, but significant, protective effect. These results indicate the possible usefulness of E3123 in the treatment of pancreatic duct obstructed pancreatitis.

Acute Disease↗

PubMed1992

Improved survival in mice with diet-induced pancreatitis treated with new potent protease inhibitor, E-3123 and a broad spectrum antibiotic, cefmetazole.

This study was designed to evaluate the infectious factor in the pathogenesis of acute pancreatitis and the effects of a combination therapy with a new potent protease inhibitor, E-3123, and a broad spectrum antibiotic cefmetazole (CMZ) in mice with CDE diet-induced severe acute pancreatitis. Combination therapy with E-3123 and CMZ showed significant protective effects against the high mortality rate, increased serum amylase and ascitic fluid amylase levels, pancreatic amylase and lysosomal enzyme content, plasma endotoxin levels, redistribution of lysosomal enzyme from the lysosomal to the zymogen fraction, lysosomal and mitochondrial fragility, and also improved the histological findings when compared with the E-3123 alone. These results suggest that infections factors play an important role in the development of severe acute pancreatitis and that protease inhibitors in combination with antibiotics may be clinically beneficial.

Acute Disease↗

PubMed1992

Protective effects of combined therapy with a protease inhibitor, ONO 3307, and a xanthine oxidase inhibitor, allopurinol on temporary ischaemic model of pancreatitis in rats.

The protective effect of a new potent protease inhibitor, ONO 3307, in combination with a xanthine oxidase inhibitor, allopurinol, was tested in pancreatico-biliary duct obstruction (PBDO) with temporary pancreatic ischemia in rats. After PBDO with ischemia, we observed hyperamylasemia, pancreatic edema, congestion of amylase and lysosomal enzyme cathepsin B as well as impaired output of amylase and cathepsin B into the pancreatic juice and a redistribution of lysosomal enzyme from the lysosomal fraction to the zymogen fraction. The administration of ONO 3307 plus allopurinol almost completely prevented the pancreatic injuries induced by PBDO with ischemia. These results indicate the important roles of temporary pancreatic ischemia in the pathogenesis of pancreatic damage and the usefulness of combination therapy with a new potent protease inhibitor and xanthine oxidase inhibitor in the protection against clinical acute pancreatitis.

Acute Disease↗

PubMed1992

Calcium uptake in the skin of a freshwater teleost.

The skin, particularly the opercular membrane of some teleosts, contains mitochondrion-rich "chloride" cells and has been widely used as a model to study branchial salt-extrusion mechanisms in seawater fish. Skin isolated from the operculum of the freshwater Nile tilapia (Oreochromis niloticus) can transport Ca2+ against an ionic and electrical gradient. Adaptation of Nile tilapia to a low-Ca2+ environment increased the capacity of the opercular membrane to transport Ca2+. The density of mitochondrion-rich cells increased in parallel with Ca2+ transport capacity. The results demonstrate net Ca2+ uptake by vertebrate skin and strongly implicate mitochondrion-rich cells as the site of Ca2+ uptake in fresh water.

Acclimatization↗

PubMed1992

Secretion of lysosomal and digestive enzymes into pancreatic juice under physiological and pathological conditions in rabbits.

To investigate the possible secretion of lysosomal enzymes into pancreatic juice during stimulation with a pancreatic secretagogue under both physiological and pathological conditions, we measured the amount of cathepsin B, a lysosomal enzyme, in the pancreatic juice during the infusion of 6 different concentrations of caerulein (0.02, 0.05, 0.2, 0.5, 1.0, and 2.0 micrograms/kg. hr). In one group of rabbits the pancreatic duct was only cannulated (free-flow group); in others the pancreatic duct was obstructed for 7 hours and secretin was infused at 0.2 CU/kg. hr (obstructed group). In addition, we evaluated the effect of the intraduodenal instillation of a liquid meal (2 g/kg) on the secretion of lysosomal enzymes into pancreatic juice. Caerulein stimulated the secretion of cathepsin B into pancreatic juice in a dose-dependent manner, as it did that of amylase, and at higher concentrations of caerulein (1.0 and 2.0 micrograms/kg. hr), both cathepsin B output and amylase output were decreased. There was a significant positive correlation between cathepsin B output and amylase output into pancreatic juice during stimulation with caerulein. Blockage of the pancreatic duct for 7 hours caused a significant rise in serum amylase levels and a redistribution of cathepsin B activity in the pancreatic subcellular fractions, as a result of which an increased amount of cathepsin B was recovered in the pellet obtained by 1000 x g centrifugation for 15 min, which contained many zymogen granules. These changes noted after short-term pancreatic duct obstruction are very similar to those previously noted in the early stage of diet-and caerulein-induced experimental pancreatitis, suggesting the colocalization of lysosomal enzyme and digestive enzymes. In the duct-obstructed animals, the secretion of cathepsin B stimulated by caerulein was significantly greater than in the free-flow group. Furthermore, the intraduodenal instillation of a liquid meal caused the secretion of cathepsin B into the pancreatic juice along with amylase. These results indicate that under physiological conditions, such as food intake, lysosomal enzymes are secreted into the pancreatic juice in response to stimulation by gut hormones in the same manner as classical pancreatic digestive enzymes. Moreover, zymogen colocalized with lysosomal enzymes in duct-obstructed animals is secreted into pancreatic juice in increased amounts together with digestive enzymes; this finding suggests that lysosomal enzymes play important pathophysiological roles in pancreatic juice and that acinar cells are altered to maintain cellular organization by secreting the potentially dangerous lysosomal enzymes. This pancreatic duct-obstructed rabbit model should be useful in clarifying the early events of acute pancreatitis.

Amylases↗

PubMed1992

Effect of 3-hour pancreatic duct obstruction on pancreatic lysosomal and digestive enzymes in rabbits.

We studied the effect of short-term (3 hours) pancreatic duct obstruction (PDO) on the exocrine pancreas and on the secretion of lysosomal enzymes into the pancreatic juice of rabbits during stimulation by pancreatic secretagogues. The following evaluations were made: serum amylase levels, pancreatic water content, pancreatic amylase, trypsinogen and cathepsin B content, and output of pancreatic enzymes and lysosomal hydrolases when stimulated by secretin and caerulein as well as the distribution of cathepsin B in subcellular fraction. PDO for 3 hours plus secretin infusion caused a significant rise in serum amylase levels, pancreatic water content, and pancreatic amylase and trypsinogen content due to congestion of digestive enzymes during PDO. There was also a redistribution of cathepsin B from the lysosomal fraction to the zymogen fraction. In normal rabbits and in those with only secretin infusion, caerulein stimulated the secretion of cathepsin B, into pancreatic juice. Just after PDO, the secretion of cathepsin B, amylase and trypsinogen significantly decreased. By 24 hours after PDO, the output of cathepsin B stimulated by caerulein and secretin had increased significantly. Amylase and trypsinogen output were also significantly increased at this stage, in both the secretin and caerulein fractions. These results indicate that the secretion of lysosomal enzymes into pancreatic juice is stimulated by gut hormones, such as caerulein, in the normal physiological state and in pathological states, such as PDO. These results also show augmented secretion of both lysosomal enzymes and pancreatic digestive enzymes in the recovery stage after PDO and their important roles at this stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Amylases↗

PubMed1992

Generation of plasmacytomas with the chromosomal translocation t(12;15) in interleukin 6 transgenic mice.

The mechanisms through which pristane or mineral oil can induce plasmacytomas in BALB/c or NZB mice are not fully understood, but involvement of interleukin 6 (IL-6), a growth factor for plasmacytomas and myelomas, has been strongly suggested. To clarify the role of IL-6 in plasmacytomagenesis, a human IL-6 cDNA was introduced into mouse germ lines under the transcriptional control of the murine major histocompatibility complex class I (H-2Ld) promoter. IL-6 transgenic mice of C57BL/6 origin developed a massive plasmacytosis but not plasmacytomas. However, introduction of BALB/c genetic background into IL-6 transgenic mice could generate monoclonal transplantable plasmacytomas with the chromosomal translocation t(12;15). These results provide firm evidence of the critical role of IL-6 in the plasmacytoma development.

Animals↗

PubMed1992

The role of interleukin 6 in plasmacytomagenesis.

Interleukin 6 (IL-6) is a polyfunctional cytokine which regulates the immune response, the acute-phase reaction and haemopoiesis. IL-6 plays a critical role in differentiation of B cells into plasma cells, and is a potent growth factor for plasmacytomas and myelomas. A relationship between IL-6 and polyclonal plasma cell abnormalities has been demonstrated. Abnormal production of IL-6 was first suggested to be related to hypergammaglobulinaemia with autoantibody production in patients with cardiac myxoma. A role of IL-6 in the generation of plasmacytoma has also been indicated. In support of these clinical and experimental observations, we demonstrated that transgenic C57BL/6 mice carrying the human IL-6 gene showed a massive polyclonal plasmacytosis with production of autoantibodies. However, the tumour was not transplantable to syngeneic animals. Susceptibility to pristane-induced plasmacytomagenesis is genetically determined--pristane can induce plasmacytomas in BALB/c but not in C57BL/6 mice. IL-6 transgenic C57BL/6 mice were backcrossed to BALB/c mice to elucidate the genetic influence on plasmacytomagenesis. Transplantable monoclonal plasmacytoma with a t(12;15) chromosomal translocation was generated in some of the backcrossed mice, indicating that IL-6 plays a key role in the multistep oncogenesis of plasma cell neoplasia.

Animals↗

PubMed1992

Direct surface cooling of the exocrine pancreas in the rat.

A study was carried out to evaluate the effects of direct cooling on the exocrine pancreas. Changes in amylase and cathepsin B release, and in the subcellular distribution of amylase and cathepsin B were measured after 1, 2 and 3 h of direct pancreatic cooling in rats. Cooling for 2 and 3 h caused significant hyperamylasaemia and increased pancreatic amylase content, but minimal histological change. Furthermore, 3 h of cooling caused marked redistribution of cathepsin B activity from the lysosomal fraction to the heavier zymogen fraction, and co-localization of lysosomal and digestive enzymes; amylase and cathepsin B output into pancreatic juice after caerulein stimulation were also reduced. These results show that direct pancreatic cooling impairs exocrine function and implicate lysosomal enzymes in the pathogenesis of pancreatic injury, in agreement with results from other models of experimental pancreatitis.

Amylases↗