[Transjugular intrahepatic portosystemic shunt for patients with hepatoma]

Nine patients with hepatoma, 5 with massive ascites, 3 with rupture of esophageal varices and 1 with hematoemesis, successfully underwent TIPS without technical complications. Two of the patients died 3 and 5 months, respectively, after TIPS due to hepatic failure and/or tumor extension. Another patient in whom hepatoma ruptured 1 month after TIPS was experienced. It is concluded that TIPS is a useful and safety treatment for portal hypertension even in patients with hepatoma which was not existed through the puncture route. However TIPS should be performed in patients in whom hepatoma has been controlled by hepatic embolization and/or ethanol injection therapy.

[MR pyelography using fast spin echo technique in hydronephrosis]

MR pyelography using the fast spin echo technique and and a body coil were performed in ten patients with hydronephrosis. In all cases, pyelograms of the dilated urinary tract were obtained by this method, although they were obtained in only two cases by drip infusion pyelography. MR pyelography is an effective method with which to obtain images of dilated urinary tract non-invasively, and in a relatively short time. This method was also useful to evaluate intraureteral structure.

Characterization of the rabbit intestinal fructose transporter (GLUT5)

Recent studies suggest that the jejunal/kidney-type facilitative glucose transporter (GLUT5) functions as a high-affinity D-fructose transporter. However, its precise role in the small intestine is not clear. In an attempt to identify the fructose transporter in the small intestine, we measured fructose uptake in Xenopus oocytes expressing jejunal mRNA from five species (rat, mouse, rabbit, hamster and guinea-pig). Only jejunal mRNA from the rabbit significantly increased fructose uptake. We also cloned a rabbit GLUT5 cDNA from a jejunal library The predicted amino acid sequence of the 487-residue rabbit GLUT5 showed 72.3 and 67.1% identity with human and rat GLUT5 respectively. Northern-blot analysis revealed GLUT5 transcripts in rabbit duodenum, jejunum and, to a lesser extent, kidney. After separation of rabbit jejunal mRNA on a sucrose density gradient, the fractions that conferred D-fructose transport activity in oocytes also hybridized with rabbit GLUT5 cDNA. Hybrid depletion of jejunal mRNA with a GLUT5 antisense oligonucleotide markedly inhibited the mRNA-induced fructose uptake in oocytes. Immunoblot analysis indicated that GLUT5 (49 kDa) is located in the brush-border membrane of rabbit intestinal epithelial cells. Xenopus oocytes injected with rabbit GLUT5 cRNA exhibited fructose uptake activity with a Km of 11 mM for D-fructose. D-Fructose transport by GLUT5 was significantly inhibited by D-glucose and D-galactose. D-Fructose uptake in brush-border membrane vesicles shows a Km similar to that of GLUT5, but was not inhibited by D-glucose or D-galactose. Finally, cytochalasin B photolabelled a 49 kDa protein in rabbit brush-border-membrane preparations that was immunoprecipitated by antibodies to GLUT5. Our results suggest that GLUT5 functions as a fructose transporter in rabbit small intestine. However, biochemical properties of fructose transport in Xenopus oocytes injected with GLUT5 cRNA differed from those in rabbit jejunal vesicles.

[Usefulness of MR cholangiography with flex coil]

Fast SE MR cholangiography was performed in 10 healthy volunteers and 10 patients with biliary disease, using body, shoulder and flex coils. Surface coils provided better images than the body coil. Although high SNR images were obtained near surface coils, signal intensity decreased in areas distant from the shoulder coil. The flex coil greatly improved image quality, especially in intrahepatic bile ducts, compared with the shoulder coil. The application of a flex coil to MR cholangiography is a highly useful method to evaluate the biliary system.

[Arterial infusion chemotherapy with human tumor necrosis factor (TNF): an experimental study using rabbits bearing VX2 tumor]

To evaluate the direct effects of TNF on tumor vessels, three groups of Japanese white rabbits bearing VX2 tumor received 5000 U, 25000, U, and 5000 U of TNF respectively. Angiograms were obtained before, and at 1, 15 and 30 minutes after arterial TNF injection. At 1 minute after TNF injection, dilated tumor vessels and dense tumor stains, depending on the dose of TNF, were demonstrated. At 30 minutes after injection these findings had disappeared However, there were no changes in normal vessels. It is suggested that arterial TNF injection influenced tumor vessels without damaging on normal vessels, indicating that it is effective as cancer therapy.

[Transjugular intrahepatic portosystemic shunt--early experience in eleven liver cirrhosis patients]

Eleven liver cirrhosis patients with variceal bleeding and/or ascites were treated by transjugular intrahepatic portosystemic shunt. Four of the patients were combined with hepatoma, and 2 had portal thrombosis. Ten of the patients were successfully achieved TIPS, but one patient who had portal thrombosis was failed because of portal vein occlusion; success rate of 90%. An average decrease of 14mmHg in portal vein pressure was measured in the 10 patients. All of the successful patients including 4 with hepatoma were observed the disappeared or diminished varices and ascites without technical complication. Mild encephalopathy was encountered in 2 patients but who responded well to medical therapy. Three dimension MRA before TIPS was helpful for understanding the anatomical relationship between portal vein and hepatic vein. It is concluded that TIPS is an effective and safe treatment, indicating for the patients who have uncontrollable variceal bleeding and/or ascites even with hepatoma.

Relationship between mean arterial pressure and muscle cell pH during forearm ischaemia after sustained handgrip

Recent evidence suggests that there is a close correlation between the physiological responses to muscle chemoreflex and the decrease in intracellular pH during ischaemia after handgrip. This study evaluated whether the relationship is linear or has an apparent threshold. We measured muscle cellular pH through phosphorous nuclear magnetic resonance spectroscopy (31P-NMR), mean arterial blood pressure (MAP) and heart rate (HR) during ischaemia after sustained handgrip exercise at 50% of maximum voluntary contraction (MVC). Contraction was sustained for 15, 30, 45 and 60 s, followed by 2 min of circulatory arrest, respectively. Muscular pH during the ischaemia decreased linearly with increasing contraction time, from the base-line level of 7.11 +/- 0.03 units (U) to 6.98 +/- 0.03, 6.90 +/- 0.04, 6.72 +/- 0.06 and 6.54 +/- 0.06 U after 15-, 30, 45-, and 60-s contractions, respectively. The MAP was 86 +/- 2 mmHg at rest and did not change during the ischaemia after 15- and 30-s contractions. However, it significantly increased to 95 +/- 2 and 107 +/- 2 mmHg, after 45- and 60-s contractions, respectively. These data indicate that the relationship between MAP and pH is not a single linear relationship, showing one breaking point around the pH of 6.90 units. It suggests that the muscle chemoreflex has a clear threshold around 6.90 units of muscle pH, and below this pH, MAP increased linearly with decreasing muscle cellular pH.

Interleukin-1 beta production in the rabbit brain during endotoxin-induced fever

Interleukin-1 beta (IL-1 beta) production in the brain and the spleen was investigated in rabbits made febrile by intravenous (I.V.) injection of endotoxin, or human recombinant IL-1 beta (hIL-1 beta). The endotoxin used in the present study was the lipopolysaccharide (LPS) of Salmonella typhosa endotoxin. Monophasic fever was induced by I.V. injection of a low dose of LPS (0.02 micrograms kg-1) and biphasic fever by I.V. injection of a large dose of LPS (4 micrograms kg-1), a sublethal dose of LPS (40 micrograms kg-1) or hIL-1 beta (2 micrograms kg-1). In situ hybridization and immunohistochemical studies revealed that, although no IL-1 beta production was observed in the brain at 1 and 3 h after injection of a low dose of LPS (0.02 micrograms kg-1) or of hIL-1 beta (2 micrograms kg-1), IL-1 beta production was demonstrated in organum vasculosum laminae terminalis (OVLT) and some cells around the blood vessels in the parenchyma 1 h after 4 micrograms kg-1 LPS. IL-1 beta production was detected throughout the brain after 40 micrograms kg-1 LPS. Pretreatment with indomethacin, an inhibitor of prostaglandin synthesis, did not affect IL-1 beta production in the brain induced by 4 micrograms kg-1 LPS. The cell type which produces IL-1 beta in the OVLT following LPS injection was confirmed to be a macrophage by electron microscopy. The cells producing IL-1 beta in the parenchyma were determined to be microglial cells. In the spleen, each dose of LPS induced a significant increase in IL-1 beta production in polymorphonuclear cells and macrophages in the red pulp 1 h after injection. However, 2 micrograms kg-1 hIL-1 beta did not induce IL-1 beta production in the spleen. The present results show clearly that systemic administration of LPS induces IL-1 beta production in the OVLT which may be responsible for induction of the second phase of biphasic fever. The production of IL-1 beta in the OVLT was not attributable to the action of peripherally synthesized IL-1 beta or prostaglandins.

ACTH response induced in capsaicin-desensitized rats by intravenous injection of interleukin-1 or prostaglandin E

1. We investigated whether afferent nerves are involved in the development of adrenocorticotrophic hormone (ACTH) responses induced either by systemic administration of interleukin-1 beta (IL-1 beta) and prostaglandin E2, or by psychological stress. The capsaicin desensitization method was used to impair afferent C fibres and we compared the ACTH responses between capsaicin desensitized and vehicle pretreated control rats. 2. The present results showed that the capsaicin desensitized rats had significantly smaller increases in plasma ACTH than the control rats in response to intravenous injection of IL-1 beta or prostaglandin E2. 3. There were no significant differences between the capsaicin desensitized and control rats in the ACTH responses induced by cage switch stress. 4. The capsaicin desensitized rats responded to intravenous injection of corticotrophin releasing factor (CRF) with a greater increase in the plasma level of ACTH than the control rats, indicating that capsaicin pretreatment resulted in augmentation of pituitary gland sensitivity to CRF. 5. These results suggest that afferent neurons play an important role in the ACTH responses induced by systemic injection of IL-1 beta or prostaglandin E2.

Cooperative roles of hepatocyte growth factor and plasminogen activator in tubular morphogenesis by human microvascular endothelial cells

Epidermal growth factor (EGF) or transforming growth factor-alpha (TGF-alpha) stimulated cell migration, chemotaxis, and the expression of tissue-type plasminogen activator (t-PA) in human omental microvascular endothelial (HOME) cells. Hepatocyte growth factor (HGF) stimulated cell proliferation, but had a negligible stimulatory effect on cell migration, the expression of t-PA and tube-like formation into collagen gel in HOME cells. Basic fibroblast growth factor stimulated cell proliferation, cell migration, tubulogenesis and the expression of urokinase-type plasminogen activator (u-PA) in bovine aortic endothelial (BAE) cells. HOME and BAE cells had both high- and low-affinity receptors for HGF. In BAE cells, u-PA activity and tube-like structures in collagen gel were induced in the presence of HGF alone. In contrast, in HOME cells, t-PA activity and tube-like structures were induced in the presence of TGF-alpha alone, but not in the presence of HGF alone. However, we observed a marked induction of tube formation by HOME cells when both t-PA and HGF were added simultaneously. In the model system for tumor angiogenesis, when HOME cells were co-cultured with a renal cancer cell line, KPK13, tube-like structures were induced in the presence of HGF:KPK13 cells expressed large amounts of t-PA mRNA. Our present study suggested that HGF in concert with active t-PA could be angiogenic in HOME cells.

Evidence that FK506 alleviates ischemia/reperfusion injury to the rat liver: in vivo demonstration for suppression of TNF-a production in response to endotoxemia

The mechanism by which FK506 (FK) prevents hepatic injury induced by ischemia/reperfusion was studied. Adult Sprague-Dawley rats were subjected to 60-min normothermic liver ischemia. Animals were divided into two groups: group I, controls, saline vehicle treatment; group II, FK treatment. FK (1 mg/kg/day, p.o.) was given for 4 consecutive days prior to inducing ischemia. In addition to a survival study, plasma levels of endotoxin and serum activities of tumor necrosis factor-alpha (TNF) and aspartate aminotransferase (AST) were assessed in the blood collected from suprahepatic vena cava. Results showed: (1) FK therapy significantly improved 7-day survival (80.0%) compared with nontreated animals (50.0%, p < 0.05); (2) both TNF and endotoxin were elevated following reperfusion, reaching maximum values at 3 h after reperfusion (217.0 +/- 40.6 and 280.5 +/- 31.4 pg/ml, respectively, in the control; mean +/- SEM), and (3) serum activities of TNF and AST following reperfusion were substantially suppressed with FK treatment, whereas FK did not reduce the rise in endotoxin. These findings suggest that suppression of TNF production in response to endotoxemia might account at least in part for the protective effect of FK against ischemia-induced hepatic injury.

[A case of cardiogenic shock caused by Vibrio parahaemolyticus]

A case of a 53 year old healthy female complaining of diarrhea and abdominal pain after taking raw fish is presented. She immediately went into shock and unconsciousness. Central venous pressure was 8 cmH2O and her ECG showed a first-degree AV block and ST-T changes in almost all leads. After mechanical ventilation and administration of dopamine, dobutamine, cefotiam, ciprofloxacin, she became alert and recovered from her critical condition. V. parahaemolyticus which produces thermostable direct hemolysin (TDH) was cultured from the feces on admission. Kanagawa phenomenon was positive. Arterial blood culture was negative and the titer of serum endotoxin was low. The diagnosis of cardiogenic shock due to exotoxin produced by V. parahaemolyticus was made. Serological examination by ELISA showed elevation of IgG class antibody against TDH and TRH (TDH related hemolysin). And antibody against TDH was normalized after 180 days. By review of literature, there are some case reports of cardiogenic shock complicated with V. parahaemolyticus infection, but few showed elevation of antibody against TDH and TRH in the serum of the survived patient.

Changes in plasma catecholamines during fever induced by bacterial endotoxin and interleukin-1 beta

We have examined whether or not the release of catecholamines into the blood circulation of rabbits during fever is mediated by prostaglandins. The plasma levels of catecholamines (epinephrine and norepinephrine) were measured in 2 ml of blood withdrawn from the marginal ear vein. At an ambient temperature of 21 +/- 1 degree C, intravenous injection of either lipopolysaccharide (LPS, 4 micrograms/kg) or human recombinant interleukin-1 beta (rIL-1 beta, 1 microgram/kg) produced a biphasic fever accompanied by an increase in the plasma level of catecholamines. Pretreatment with intravenous indomethacin (1 mg/kg) markedly suppressed the increase in catecholamines induced by LPS and rIL-1 beta. In contrast, although intracerebroventricular injection of rIL-1 beta (20 ng) produced fever, it did not produce a significant change in plasma catecholamine levels. Similarly, intrahypothalamic injection of prostaglandin E2 (200, 800 ng) induced fever, but did not cause a significant change in catecholamine concentrations. These results suggest that IL-1 acts via prostaglandins on the peripheral tissues to release catecholamines into the circulation.

Augmentation of hepatocyte proliferation by immunosuppressant pretherapy is associated with up-regulation of malondialdehyde production

We studied the relationship between augmentation of liver regeneration with immunosuppressants and malondialdehyde (MDA, an end-product of lipid peroxides) production. MDA was determined using the thiobarbituric acid reaction. Rats underwent a 4-day treatment of FK506 (FK, 1 mg/kg per day), cyclosporine (Cs, 10 mg/kg) or azathioprine (AZA, 1 mg/kg) by gavage prior to 70% hepatectomy. They were then divided into four groups: (1) controls (vehicle-treated); (2) FK; (3) Cs; (4) AZA. MDA levels, uptake of BrdU (5-bromo-2-deoxyuridine) in the liver and serum biochemistry were investigated 24 h after hepatectomy. Immunosuppressant pretherapy significantly stimulated BrdU uptake by hepatocytes, in association with increased MDA production, while there were no differences in serum liver injury parameters among the groups given or not given immunosuppressants. The implications of the rising MDA values during liver regeneration are discussed with respect to immunosuppression and a measure of lipid peroxidation. Additional study indicated that one immunodepressant pretreatment (24 h prior to hepatectomy) was effective for up-regulation of liver regeneration.

Cardiovascular, thermal and behavioral sensitization to methamphetamine in freely moving rats

Mean arterial blood pressure (MAP), heart rate (HR), body temperature (BT) and locomotive activity (LA) were measured simultaneously after i.p. or i.c.v. injection of methamphetamine (MAH) using a biotelemetric system. The system enabled us to observe the parameters in freely moving rats under minimum stress. MAH (1 mg/kg) given by i.p. injection significantly increased MAP, HR, BT and LA, as compared with the saline-control. MAH (5, 50 micrograms) administered by i.c.v. injection stimulated responses of HR, BT and LA. After the i.p. injections of MAH (1 mg/kg) on days 1, 4, 8, 11 and 15, MAH was administered either through i.p. (1 mg/kg) or i.c.v. (50 micrograms) route on day 18. In addition to the LA sensitization induced by i.p. and i.c.v. administration of MAH, it was found for the first time, to our knowledge, that the repeated i.p. injections potentiated the responses of MAP and BT to the subsequent injection of MAH through i.p., but not i.c.v., route. The latter finding suggests that the sensitization, produced by the repeated i.p. injections, affected responses that MAH induced either peripherally or centrally through a peripheral humoral factor or an afferent nervous system.

Anti-angiogenic activity of arachidonic acid metabolism inhibitors in angiogenesis model systems involving human microvascular endothelial cells and neovascularization in mice

We have established an in vitro angiogenesis model using human omental microvascular endothelial (HOME) cells, in which epidermal growth factor (EGF) or transforming growth factor-alpha (TGF-alpha) stimulated cell migration and tube formation. In this study, we examined whether alpha-guaiaconic acid (GR-12) and its synthetic 20 derivatives showed inhibition of cell migration and tubular formation of HOME cells. We found that GR-12 inhibits arachidonic acid metabolism, while GR-12 and one derivative, GS-01, inhibit tubular formation of endothelial cells in our model system. Confluent monolayers of HOME cells were damaged with a razor blade and incubated with or without TGF-alpha; HOME cell migration was stimulated about 1.5-fold over control values in the presence of TGF-alpha. Treatment of HOME cells with GR-12 or GS-01 inhibited both spontaneous and TGF-alpha-stimulated migration. GR-12 or GS-01 inhibited TGF-alpha-induced HOME-cell tube formation in type-1 collagen gels. We examined whether these compounds could modulate tubular formation of HOME cells induced by human cancer cells. Enhanced tube formation of HOME cells by co-cultured esophageal cancer cells was almost completely inhibited by co-administration of GR-12 or GS-01. Both compounds also inhibited formation of tubular networks of HOME cells on Matrigels. We also examined anti-angiogenic activity of these compounds in an in vivo model system of tumor angiogenesis in mice. In this system, GS-01 inhibited development of capillary networks at a rate comparable to that of a well-known anti-angiogenic compound, fumagillin, but GR-12 did not. The inhibitor of arachidonic acid metabolism is thus expected to modulate tumor angiogenesis.

Morphological change and destabilization of beta-actin mRNA by tumor necrosis factor in human microvascular endothelial cells

Tumor necrosis factor-alpha (TNF-alpha) produced morphological changes from a cobblestone-like shape into a spindle shape in human omental microvascular endothelial (HOME) cells and also a drastic rearrangement of actin filaments. Expression of beta-actin gene was diminished in HOME cells treated with TNF-alpha for 24 h. Northern blot analysis of the beta-actin gene demonstrated that the cellular level of beta-actin mRNA was decreased at 6-12 h after exposure to TNF-alpha. However, there appeared to be no changes in cellular mRNA levels of beta-tubulin, fibronectin, laminin B1, laminin B2, and laminin binding protein genes after treatment with TNF-alpha. Nuclear run-on assays showed increased transcription of the low-density lipoprotein receptor gene, but not of the beta-actin gene. These data suggested that the TNF-alpha-induced inhibition of beta-actin gene expression was not due to altered transcription activity. The degradation rates of beta-actin, plasminogen activator inhibitor-1, and epidermal growth factor receptor mRNAs were examined in the presence of actinomycin D. beta-Actin mRNA was found to be specifically destabilized in TNF-alpha-treated HOME cells, while other mRNA species were not. Coadministration of cycloheximide blocked the TNF-alpha-induced degradation of beta-actin mRNA. The TNF-alpha-induced destabilization of beta-actin mRNA and rearrangement of actin filaments are discussed in relation to the morphological changes in human microvascular endothelial cells.

Effect of a central CRF antagonist on cardiovascular and thermoregulatory responses induced by stress or IL-1 beta

We investigated the role of central corticotropin-releasing factor (CRF) in the development of cardiovascular and thermal responses induced by stress or by interleukin-1 beta (IL-1 beta) in free-moving rats. Intracerebroventricular (icv) injection of alpha-helical CRF9-41 (10 micrograms), a CRF receptor antagonist, significantly attenuated hypertension, tachycardia, and a rise in body temperature induced by cage-switch stress, a mild stress. However, icv injection of alpha-helical CRF9-41 (10 micrograms) had no effect on hypertension, tachycardia, or fever induced by intraperitoneal (ip) injection of IL-1 beta (2 micrograms/kg) or icv prostaglandin E2 (PGE2, 100 ng). In contrast, icv injection of alpha-helical CRF9-41 (10 micrograms) significantly attenuated hypertension, tachycardia, or fever induced by icv injection of IL-1 beta (20 ng). The present results suggest that central CRF has an important role in the development of the cage-switch stress-induced responses, but it does not seem to contribute to the hypertension, tachycardia, and fever induced by ip IL-1 beta or by central PGE2. However, it is possible that when IL-1 beta directly acts on the central nervous system, some of its actions are mediated by central CRF.

[Percutaneous arterial prostheses of femoro-femoral bypass: using a new method of Modified Seldinger technique]

An experimental study of percutaneous arterial prostheses of femoro-femoral bypass was performed in 3 dogs using Modified Seldinger technique. Modified Seldinger technique with an arc needle was a newly designed method to penetrate the arterial wall due to introduce a bypass graft into the artery percutaneously. In all dogs, the bypass graft was successfully placed and proved to be effective in excellent blood flow. No significant complication was encountered. It is concluded that this method is feasible in the dog model.

Organum vasculosum laminae terminalis (OVLT) is a brain site to produce interleukin-1 beta during fever

The present study was carried out to determine whether interleukin-1 (IL-1) production occurs in the rabbit organum vasculosum laminae terminalis (OVLT) during fever induced by endotoxin. The intravenous (i.v.) injection of endotoxin (4 micrograms/kg) caused significant fever in rabbits. Through the use of in situ hybridization and immunohistochemical techniques, the synthesis of IL-1 was observed in the OVLT during the fever. The present results support the hypothesis that IL-1 is produced in the brain during fever.

Intravenous digital subtraction angiography of the internal jugular veins

92 patients with various head-related symptoms were underwent study with IV-DSA. The width and density of the internal jugular veins were compared with the width and density of the common carotid arteries. The right internal jugular vein was more than twice as broad as the common carotid artery in 58 patients (63%), and was denser than the common carotid artery in 14 patients (15%). On the other hand, the left internal jugular vein was broader than the common carotid artery in 76 patients (83%) and more than twice as broad as the common carotid artery in 19 patients (21%). However, the left jugular vein was narrower than the common carotid artery in 12 patients (13%), and in 5 patients (5%) could not be demonstrated. If it is recalled that the internal jugular veins are sometimes congenitally aplastic or hypoplastic as developmental variations of the confluence of sinuses, the occurrence of complications associated with retrograde catheterization can be minimized.

Febrile and metabolic tolerance to endotoxin and human recombinant interleukin-1 beta in rabbits

We investigated whether or not tolerance of the febrile and metabolic responses to human recombinant interleukin-1 beta (IL-1 beta) develops in rabbits. Febrile tolerance to bacterial endotoxin was induced by daily injections of lipopolysaccharide (LPS, 5.0 micrograms/kg iv). In LPS-tolerant rabbits, the second phase of the biphasic fever induced by intravenous injections of LPS (5.0 micrograms/kg) or IL-1 beta (2.0 micrograms/kg) was significantly reduced. However, the first phase was almost the same as that observed in normal rabbits. Five daily injections of IL-1 beta (2.0 micrograms/kg iv) resulted in the development of tolerance of the febrile response to IL-1 beta. In IL-1 beta-tolerant rabbits, the second peak of the biphasic fever was significantly reduced. In addition, decreases in leukocyte count and plasma zinc induced by intravenous injections of LPS or IL-1 beta were significantly reduced in LPS- or IL-1 beta-tolerant rabbits. However the monophasic fever induced by a smaller dose of IL-1 beta (0.5 microgram/kg iv) and the first peak of the IL-1 biphasic fever were almost the same as those observed in normal rabbits. Febrile responses induced in LPS- or IL-1 beta-tolerant rabbits by intracerebroventricular injections of LPS (5.0 ng) or IL-1 beta (2.0 ng) were similar to those observed in normal rabbits. The present results suggest that tolerance of the febrile and metabolic responses to IL-1 beta is developed after repeated injections of IL-1 beta and that reduced responsiveness to IL-1 beta is partly involved in the development of LPS tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Irsogladine is a potent inhibitor of angiogenesis

We describe a novel inhibitor of angiogenesis, Irsogladine, an anti-ulcer drug. Irsogladine inhibited plasminogen activator synthesis of, and tube formation by, human microvascular endothelial cells in type 1 collagen gel treated with an angiogenic growth factor, EGF. Furthermore, Irsogladine administered orally significantly inhibited in vivo angiogenesis in mice. Irsogladine may be useful in the treatment of diseases associated with angiogenesis.

Light- and electron-microscopic localization of basic fibroblast growth factor in adult rat retina

An antiserum against basic fibroblast growth factor (bFGF) was characterized by immunoblot and used to localize bFGF-immunoreactivity in the adult rat retina. Crude homogenate of the retina, when examined with immunoblotting, exhibited a main band with the same molecular weight (18kDa) as bFGF. Light microscopic immunohistochemistry demonstrated intense bFGF staining in the photoreceptor outer segments and the outer plexiform layer, and weak immunostaining in some cells of the outer nuclear layer, inner nuclear layer and ganglion cell layer. The most intense bFGF-immunoreactivity was noted in glial (Müller) cells with vertically oriented thin processes. There were also immunoreactive pigment epithelial cells and mesenchymal cells in the choroid. Under electron microscopy, the outer plexiform layer was found to contain immunoreactive products exclusively in the axon terminals of photoreceptor cells which formed synapses with bipolar cell processes. The more widespread and uneven localization of bFGF-immunoreactivity in the mature rat retina than previously demonstrated suggests that endogenous bFGF is involved in complex physiological events other than retinal regeneration and histogenesis.

Organum vasculosum laminae terminalis (OVLT) in rabbit and rat: topographic studies

The microcirculation and fine structure of the rabbit and rat organum vasculosum laminae terminalis (OVLT) were examined by light microscopy and scanning and transmission electron microscopy. In both animals, the microcirculation is composed of a superficial and a deep vascular bed but the system is more complex and extensive in the rabbit. This was particularly true of the deep vascular bed. In the rabbit, the deep bed is composed of fenestrated capillaries, which are arranged in glomerular tufts surrounded by very wide perivascular spaces (PVS). In contrast, the deep vascular bed of the rat OVLT usually consists of only one or two small vessels. These are either fenestrated and surrounded by a PVS or lined by continuous endothelium with only a few fenestrae and without a dilated PVS. A corresponding difference was seen in the contours of the ventricular surface. It is much more irregular in the rabbit than in the rat and numerous bulges reflect the underlying vascular tufts and pockets of PVS in the rabbit. Supraependymal cells are present in both species and two sizes of them occur in the rabbit. The results demonstrate that the microcirculation of the OVLT is more elaborate and more highly developed in the rabbit than in the rat. We suggest that this might result in a different neurohemal microenvironment and, ultimately, in functional differences.

Intra-arterial digital subtraction portography with a blood-isotonic, non-ionic, dimeric contrast medium

Intra-arterial digital subtraction portography (IA-DSP) with a blood-isotonic, non-ionic, dimeric contrast medium was carried out in 27 patients with hepatocellular carcinoma. It was possible to obtain images of excellent or good quality of the portal vein and its bilateral main branches in all patients. The third-order branches of the portal vein in the right lobe could be identified in all patients, and images of excellent or good quality were obtained in a mean of 80.2% of patients. Images of third-order branches in the left lobe were of lower quality than those of third-order branches in the right lobe; in particular, images obtained were of poor quality for 27.3% of the medial branches of the left lobe. It was impossible to identify the caudal branches in almost all patients. The side effects of IA-DSP, pain and sensations of heat were very mild: only one patient complained of mild pain, while 18 patients (69.2%) complained of no sensations of heat whatsoever.

Indispensable role of tissue-type plasminogen activator in growth factor-dependent tube formation of human microvascular endothelial cells in vitro

Epidermal growth factor (EGF) stimulates the migration and proliferation of, and tissue-type plasminogen activator (tPA) synthesis in, human omental microvascular endothelial (HOME) cells in culture, as well as inducing the formation by these cells. In the present study, we examined the effects of various growth factors, i.e., transforming growth factor-alpha (TGF-alpha), insulin-like growth factor 1 (IGF-1), and hepatocyte growth factor (HGF) on HOME cells, and compared their effects with that of EGF. IGF-1 stimulated the proliferation and migration of these cells at a level comparable to EGF. EGF and TGF-alpha induced expression of tPA in HOME cells, while IGF-1 and HGF did not. EGF and TGF-alpha induced tube formation by HOME cells in type I collagen gel, while IGF-1 and HGF did not. The stimulatory effect of EGF on tube formation in the gel was blocked by anti-tPA antibody and by a serine protease inhibitor, aprotinin. When exogenous tPA and IGF-1 or HGF were added simultaneously to the culture, a marked induction of tube formation in the gel was observed. Exogenously added tPA alone, however, had no such inducible effect on tube formation. These results indicated an indispensable role of tPA in growth factor-dependent tube formation by HOME cells. Two subsets of growth factors appeared to modulate angiogenesis: One with fully active angiogenic activity which could induce PA (this included EGF and TGF-alpha), and the other, which could not induce PA and was not angiogenic, but could promote angiogenesis in the presence of PA. This subset included IGF-1 and HGF.

Effects of alpha- and beta-adrenergic antagonists on rise in body temperature induced by psychological stress in rats

We investigated the effects of intraperitoneal injection of alpha- and beta-adrenergic antagonists on psychological stress-induced responses in free-moving rats. Psychological stress was induced by immersion in 2-cm-deep water. The intraperitoneal injection of the alpha-adrenergic blocker, phentolamine (10 mg/kg), attenuated the stress-induced rise in body temperature and hypertension but enhanced tachycardia. In contrast, intraperitoneal injection of the beta-adrenergic blocker, propranolol (1 mg/kg), suppressed tachycardia but had no effect on rise in body temperature and hypertension during stress. The intraperitoneal injection of both blockers had no effect on the increase in metabolic rate (O2 consumption) induced by stress. The intravenous injection of propranolol (1 mg/kg) suppressed the stress-induced rise in body temperature. We then examined the effect of intracerebroventricular injection of propranolol on the stress-induced rise in body temperature and found that intracerebroventricular injection of propranolol (50 micrograms) suppressed the stress-induced rise in body temperature. These results support the following hypotheses: 1) Systemic injection of phentolamine suppresses the psychological stress-induced rise in body temperature by facilitating heat-loss; 2) Peripheral beta-adrenergic stimulation probably does not contribute to psychological stress-induced rises in body temperature; and 3) central beta-adrenergic receptors are important in stress-induced increases in body temperature.

The central role of corticotrophin-releasing factor (CRF-41) in psychological stress in rats

1. We investigated the central role of corticotrophin-releasing factor (CRF-41) in psychological stress-induced responses, including cardiovascular, thermoregulatory and locomotive activity in free-moving rats. 2. Psychological stress was induced by cage-switch stress. After rats were placed in the novel environment, blood pressure, heart rate, body temperature and locomotive activity significantly increased. The intracerebroventricular (I.C.V.) injection of alpha-helical CRF(9-41), a CRF-41 receptor antagonist, significantly attenuated the stress-induced hypertension, tachycardia, hyperthermia and increase in locomotive activity. However, in unstressed rats, the I.C.V. injection of alpha-helical CRF(9-41) had no effect on physiological parameters measured in this study. 3. In unstressed rats, the I.C.V. injection of CRF-41 (1 microgram and 10 micrograms) increased blood pressure, heart rate, body temperature and locomotive activity in a dose-dependent manner. The changes in these responses were quite similar to those observed during cage-switch stress. 4. The results suggest that central CRF-41 plays an important role in psychological stress-induced hypertension, hyperthermia, tachycardia and increase in locomotive activity. However, it is likely that central CRF-41 does not contribute to normal cardiovascular and body temperature regulation when rats are free from stress.

Effects of electrical stimulation or local anesthesia of the rabbit's hypothalamus on the acute phase response

The effects of electrical stimulation of the rostral hypothalamic region on the acute phase response (APR) were examined in rabbits. As indicators of APR, we measured changes in the plasma concentrations of iron, zinc, copper, and fibrinogen and changes in the red and white blood cell counts. Electrical stimulation of the rostral hypothalamic region near the preoptic and anterior hypothalamic region did not induce any aspect of the APR. However, stimulation near the anteroventral portion of the third ventricle (AV3V) induced responses that were, in part, opposite to those observed in the APR: an increase in the plasma concentration of zinc and a decrease in the circulating leukocyte count. Microinjections of procaine into the brain regions near the AV3V did not induce any changes in the plasma levels of trace metals and fibrinogen but increased the circulating leukocyte count. These results suggest that nonspecific stimulation or inhibition of the rostral hypothalamic region does not induce APR.

Running training attenuates the ACTH responses in rats to swimming and cage-switch stress

The present study was carried out to investigate the effect of running training on adrenocorticotrophic hormone (ACTH) response in rats to swimming or cage-switch stress to determine whether, after physical training, a cross-adaptation develops in the ACTH responses induced by different types of stresses. Rats were trained by two different kinds of exercises and for two different periods of training: 1) swimming for 4 wk (4W-swimming), 2) running for 4 wk (4W-running), and 3) running for 10 wk (10W-running). Remaining rats were used for control for 4 wk (4W-control) and 10 wk (10W-control). The ACTH response induced by swimming stress was reduced after training by swimming (62.4%) or by running (13.8-16.4%). These training periods also attenuated the ACTH response induced by cage-switch stress (62.4% in the swimming group, 23.8-34.6% in the running groups). After swimming stress, the 4W-swimming and 10W-running groups showed smaller increases in blood glucose than the control groups. In addition, the increased levels of blood lactate in all the trained rats were significantly smaller than those in the control groups, suggesting that an adaptation was achieved after physical training. These results suggest that after running training, cross-adaptation is developed in the ACTH response induced by different types of physical (swimming) or psychological (cage-switch) stresses.

Systemic injection of TNF-alpha attenuates fever due to IL-1 beta and LPS in rats

The effect of tumor necrosis factor-alpha (TNF-alpha) on the febrile response to interleukin-1 beta (IL-1 beta) was investigated in rats. While both of these substances are capable of causing fever when injected into rats, an earlier study showed that the injection of antiserum against TNF-alpha enhanced endotoxin [lipopolysaccharide (LPS)] fever, suggesting that physiological levels of circulating TNF may act to limit the magnitude of fever. In the present study, the intraperitoneal injection of 1 microgram/kg of TNF-alpha significantly attenuated the fever due to the intraperitoneal injection of 10 micrograms/kg of IL-1 beta. Higher doses of TNF-alpha (10 and 50 micrograms/kg injected ip) slightly lowered the febrile response to this dose of IL-1 beta, but these changes were not significant. None of these doses of TNF-alpha alone significantly altered body temperature. The injection of 1 microgram/kg of TNF-alpha also significantly lowered the febrile response to the intraperitoneal injection of 10 micrograms/kg of LPS. The febrile responses to the preoptic area (POA) or intraperitoneal injection of IL-1 beta were not changed when a nonpyrogenic dose of TNF-alpha was simultaneously injected into the POA. Further studies are needed, however, before we can conclude that TNF does not act in the central nervous system to control the febrile response. These data support the hypothesis that nonpyrogenic levels of TNF act in the systemic circulation to suppress the development of fever.

Clinical evaluation of interventional radiology for renal cell carcinoma in 100 patients

One hundred of 160 patients with renal cell carcinoma (RCC) were treated by interventional radiology (IVR) in the period from 1978 to 1989. The number and kind of interventions done each year were classified retrospectively. More than half of the patients underwent therapeutic arterial embolization or intraarterial infusion of anticancer drugs during the first half of the period. More recently, about half of the patients have had nephrectomies without IVR. One patient with advanced RCC by IVR 18 times lived 8 years and three months after diagnosis, but that was exceptionally long. IVR has been more effective against hepatocellular carcinoma than RCC, for several reasons.

Isolation of a novel protein from the outer layer of the vitelline membrane

The outer layer of the vitelline membrane from hen egg yolk consists of ovomucin, vitelline membrane outer layer protein I (VMOI) and lysozyme. Here we report the occurrence of a further basic protein (pI 11.5) in the outer layer, which was designated as vitelline membrane outer layer protein II (VMOII). It was dissociated from the outer layer in a 10% (w/v) NaCl solution and purified to homogeneity by ion-exchange chromatography. VMOII is a simple protein with a molecular mass of 6000 Da, as determined by sedimentation equilibrium analysis. The amino acid composition of VMOII was characterized by the absence of Met and high contents of cystine (half) (14%) and basic amino acids (6% Arg, 6% Lys and 3% His). Analysis of carboxymethylated VMOII indicated that all cysteine residues were involved in disulphide bonding, which appears to facilitate the binding of SDS to the protein. Sequence comparison of the N-terminal 20 residues revealed no identity with other known proteins. VMOII contained a small amount of alpha-helix and was quite resistant to heat denaturation.

A model system for tumor angiogenesis: involvement of transforming growth factor-alpha in tube formation of human microvascular endothelial cells induced by esophageal cancer cells

Tumor growth is dependent on angiogenesis, which is thought to be mediated through growth factors, such as transforming growth factor-alpha (TGF-alpha) and -beta (TGF-beta), epidermal growth factor (EGF), and basic fibroblast growth factor (bFGF), produced by tumor cells. We have developed a model system for tumor angiogenesis in vitro: tube formation of human omentum microvascular endothelial (HOME) cells in type I collagen gels when these cells are co-cultured with tumor cells. Exogenously added TGF-alpha induced tube formation of HOME cells in collagen gel. In contrast, TGF-beta inhibited the TGF-alpha-induced tube formation of endothelial cells. We investigated whether tube formation could be induced in HOME cells in collagen gel when the HOME cells were co-cultured with three esophageal cancer cell lines, TE1, TE2, and TE5. TE1 and TE2 cells expressed both TGF-alpha and TGF-beta mRNA, but the level of TGF-alpha mRNA in TE2 was found to be much lower than in TE1 cells. TE5 did not express either TGF-alpha or TGF-beta. The tube formation of HOME cell was induced when they were co-cultured with TE1 cells, while both TE2 and TE5 cell lines induced tube formation at much lower rates than TE1. TE1-induced tube formation of HOME cells was specifically blocked by co-administration of anti-TGF-alpha-antibody, but not by anti-bFGF-antibody. The present study suggests that, in our model system, esophageal tumor angiogenesis is partly controlled by TGF-alpha, possibly through a paracrine pathway.

Does an increase in prostaglandin E2 in the blood circulation contribute to a febrile response in rabbits?

We investigated the effect of intravenous injection of human recombinant interleukin-1 beta (IL-1) on rectal temperature and prostaglandin E2 concentration in venous and arterial blood and in the push-pull perfusate in the third ventricle of rabbits. Changes in plasma prostaglandin E2 concentration in blood obtained from the marginal ear vein paralleled changes in body temperature during both monophasic and biphasic fevers. The plasma concentration of prostaglandin E2 in blood obtained from the jugular vein increased during the first phase of the biphasic fever. However, no increase in the prostaglandin E2 level in the carotid arterial blood was observed during the biphasic fever. The levels of prostaglandin E2 in the push-pull perfusate in the third ventricle were markedly elevated during both monophasic and biphasic fevers. Intracarotid infusion of prostaglandin E2 did not produce a fever nor result in a change in the prostaglandin E2 concentration of the push-pull perfusate in the third ventricle. The present results suggest that prostaglandin E2 from the blood circulation does not contribute to fever production in rabbits.

Regional differences in myosin heavy chain isoforms and enzyme activities of the rat diaphragm

Myosin heavy chain isoforms and enzyme activities were compared between the costal and crural regions of the rat diaphragm. The percentage of heavy chain (HC) IIb in the crural region of the diaphragm was significantly (P less than 0.05) higher than that in the costal region (mean 7.3 vs. 3.0%), and the percentage of HCI was significantly lower in the crural than in the costal diaphragm (22.7 vs. 27.9%). The distributions of HCIIa and HCIId were relatively homogeneous in both regions. Succinate dehydrogenase activity in the costal diaphragm was 21% greater (P less than 0.01) than in the crural diaphragm. In contrast, there was no significant difference in the activity of phosphofructokinase in the crural and costal diaphragms. These results demonstrate that a difference in myosin heavy chain isoforms and oxidative capacity exists between the costal and crural regions of the rat diaphragm.

Induction of low density lipoprotein receptor and a transcription factor SP-1 by tumor necrosis factor in human microvascular endothelial cells

We have previously reported that tumor necrosis factor-alpha (TNF-alpha) enhances expression of interleukin-6, collagenase, plasminogen activator inhibitor-1, and basic fibroblast growth factor genes in human omental microvascular endothelial (HOME) cells in culture. In this study, we found that treatment of HOME cells with TNF-alpha or interleukin-1 (IL-1) caused enhanced expression of low density lipoprotein (LDL) receptor. A few-fold increase in both LDL binding activity and the receptor mRNA levels was observed when HOME cells were treated with either TNF-alpha or IL-1. Northern blot analysis showed that cellular expression of LDL receptor gene was significantly increased 12-24 h after exposure to TNF-alpha. No significant changes in the life-span of LDL receptor mRNA were observed in untreated and TNF-alpha-treated cells. Scatchard analysis showed an increased receptor number for LDL in TNF-alpha-treated cells. Parallel to increased LDL binding activity, internalization and degradation of LDL were also increased in HOME cells treated with TNF-alpha or IL-1. TNF-alpha-induced enhancement of LDL receptor gene expression was not observed when cycloheximide was present. Cellular mRNA level of SP-1 gene was increased about 3-4-fold at 12 h after treatment with TNF-alpha. Nuclear run-on assays showed increased transcription of LDL receptor gene as well as SP-1 gene by TNF-alpha. Gel retardation assay with the SP-1 consensus fragment showed that SP-1 binding activity was increased about 4-5-fold 12-24 h after treatment with TNF-alpha. NF-kB binding activity was also dramatically increased, but there is no NF-kB motif on the promoter for LDL receptor gene. The induction of LDL receptor by TNF might be mediated through a transcription factor, SP-1.

A binding profile of manganese to the nucleus of rat liver cells, and manganese-induced aberrations in thyroid hormone content and RNA synthesis in the nucleus

Manganese (Mn) is accumulated in the nuclear and mitochondrial fractions when excess Mn is administered. However, little is known with respect to the behaviors of Mn in nuclei. In the present study, rats were given excess Mn and the nuclei were purified from liver cells by differential and sucrose gradient centrifugations. Being subjected to equilibrium dialysis with a radioactive 54Mn, the binding capacity of Mn in nuclei from the control rat was five-fold higher than BSA, which was used as a reference protein; and the capacity of 54Mn-binding rose in the nuclei from the Mn-treated animals in comparison with those from the control. On the analyses of nuclear materials with partial solubilization, sepharose column chromatography and HPLC, there were two major fractions which associated with a lot of Mn; one fraction was of large molecules of DNA, and the other fraction seemed to be peptides with small molecular weights. Therefore, Mn may open up a superhelical structure of DNA to provide more negatively charged phosphate moiety as a binding-site for a positively charged Mn. The results also disclosed a possible aberration in biological functions due to excess Mn in nuclei; the apparent association constant of triiodothyronine, a physiologically active thyroid hormone, to the nucleus was reduced by 75% and the uptake of 14C-labelled orotic acid to a newly synthesized RNA in the liver was severely inhibited.

Effects of running training on the blood glucose and lactate in rats during rest and swimming

The purpose of this study was to examine the effect of physical training on the concentrations of glucose and lactate in the blood of rats during rest and after an acute bout of exercise. We used the following types and periods of training; (i) swimming for 4 weeks, (ii) running for 4 weeks, and (iii) running for 10 weeks. The results clearly show that the resting levels of blood glucose was significantly lower in groups trained by either swimming or running than untrained groups. In addition, after the acute exercise of swimming, animals trained by either running or swimming showed a lower increase in the blood lactate than untrained animals. Furthermore, the increases in the blood glucose after swimming were significantly lower in the group trained by swimming for 4 weeks and by running for 10 weeks than in untrained groups. These results suggest that after physical training by running, animals show an adaptation in the changes in the blood glucose and the blood lactate that are induced by a different type of physical stress, swimming.

Effects of endurance training on myosin heavy-chain isoforms and enzyme activity in the rat diaphragm

We investigated the effects of endurance training (20 m/min, 60 min/day, 5 days/week) on myosin heavy-chain (MHC) isoforms and succinic dehydrogenase (SDH) activity in rat crural and costal diaphragms, and plantaris muscles. Although the 4-week endurance training produced significant (P less than 0.05) increases, both in SDH activity and the percentage of isoform HCIIa in the plantaris of the trained rat compared with the sedentary control rat, these alterations did not occur in either the crural or costal diaphragms. After 10 weeks of endurance training, trained animals had significantly (P less than 0.05) higher SDH activity in the costal diaphragm and the plantaris. Moreover, a significant (P less than 0.05) decrease occurred in the percentage of HCIIb in the costal diaphragm, and a significant (P less than 0.01) decrease in the percentage of HCIIb concomitant with a significant (P less than 0.05) increase of HCIIa resulted in the plantaris. However, the crural diaphragm did not show any significant changes after 10 weeks of endurance training. These results indicate that endurance training induces an alteration in the expression of an MHC phenotype, in addition to causing an increase in oxidative enzyme activity. However, the alterations in response to endurance training are apparently not uniform, varying between regions and/or kinds of muscles.

Decreased response to epidermal growth factor during cellular senescence in cultured human microvascular endothelial cells

We have previously demonstrated that epidermal growth factor (EGF) induces cell migration, tissue-type plasminogen activator synthesis, as well as tubular formation in microvascular endothelial cells from human omental tissue. In this study, we compared the responsiveness to EGF of late passaged (senescent) human omental microvascular endothelial (HOME) cells with that of early passaged (young) HOME cells. We have employed HOME cells derived from surgically resected omental samples from 14 patients. EGF-stimulated cell migration significantly more in the young cells than in the senescent cells during serial cultivation (aging) in vitro. Scatchard analysis demonstrated that the number for both high and low affinity receptors for EGF in HOME cells was decreased dramatically during serial cultivation. The expression of EGF receptor mRNA was also decreased in the senescent HOME cells. Treatment of HOME cells with EGF significantly increased cellular mRNA levels of tissue-type plasminogen activator, and two protooncogenes, c-fos and c-myc, in young HOME cells, but not in senescent HOME cells. Thus HOME cells aged in vitro show a decreased responsiveness to EGF, resulting in decreased migration of human endothelial cells. The serial cultivation of human endothelial cells in vitro may downregulate EGF receptor and decrease responsiveness to exogenous EGF, a potent angiogenic factor.

Cardiovascular responses induced in free-moving rats by immune cytokines

1. We investigated the effect of intraperitoneal (I.P.) injections of the immune cytokines, interleukin-1 beta (IL-1 beta) and tumour necrosis factor (TNF) on cardiovascular responses in free-moving rats, using a biotelemetry system. 2. The I.P. injection of a small dose of IL-1 beta (1 microgram/kg) induced a monophasic increase in the heart rate, and that of a large dose (10 micrograms/kg) induced biphasic increases in the blood pressure and heart rate. However, the I.P. injection of any of several doses of TNF (1, 10 and 50 micrograms/kg) had no effect on cardiovascular responses in rats. 3. Pre-treatment with I.P. injection of indomethacin (10 mg/kg), an inhibitor of cyclo-oxygenase, significantly suppressed the cardiovascular responses and the increase in the plasma noradrenaline (NA) concentration induced by I.P. injection of IL-1 beta. 4. Microinjection of IL-1 beta (1 and 10 ng) into the preoptic and anterior hypothalamic (PO-AH) region induced dose-dependent increases in the blood pressure and heart rate in rats. These responses were also suppressed by pretreatment with I.P. indomethacin (10 mg/kg). In addition, microinjection of prostaglandin E2 (20 and 100 ng) into the PO-AH region increased blood pressure and heart rate, but that of prostaglandin D2 (100 ng) had no effect. 5. The present results suggest that IL-1 beta stimulates the release of prostaglandins, presumably E series, near regions of the hypothalamus, which act on the hypothalamus to induce activation of the sympathetic nervous system. Subsequently, the blood pressure, heart rate and the plasma level of NA increase.

Intraperitoneal injections of prostaglandin E2 attenuate hyperthermia induced by restraint or interleukin-1 in rats

1. The purpose of this study was to investigate the effect of the intraperitoneal (I.P.), intravenous (I.V.) or intrapreoptic area (POA) injection of prostaglandin E2 (PGE2) on the body temperature of restrained and unrestrained rats. The effect of I.P. PGE2 on the body temperature of rats during fever induced by I.P. injection of interleukin-1 beta (IL-1 beta) was also investigated. 2. Prior to injection, restrained rats had body temperatures of approximately 1 degree C higher than unrestrained rats. The I.P. injection of PGE2 (0.05 and 0.5 mg kg-1) caused body temperature to fall towards the pre-restraint levels in a dose-dependent manner. This fall in body temperature was preceded by a sharp increase in tail skin temperature that was also dependent on dose. The I.P. injection of PGE2 had no effect on the body temperature of unrestrained animals. 3. The I.V. injection of PGE2 caused very little change in the body temperature of restrained rats. However, when injected I.V. into unrestrained animals, PGE2 caused dose-dependent fevers. The injection of PGE2 (50 ng) into the POA resulted in fever in both restrained and unrestrained animals. 4. The I.P. injection of IL-1 beta (10 micrograms kg-1) caused a biphasic fever that lasted at least 420 min. The I.P. injection of PGE2 180 min after the injection of IL-1 beta caused a transient decrease in the rats' body temperature. This drop in body temperature was not associated with a decrease in metabolic rate. 5. These data support the hypothesis that during restraint stress hyperthermia and IL-1 beta fever, the I.P. injection of PGE2 acts peripherally to lower the body temperature of rats.

Threshold dose of interleukin-1 beta for induction of an ACTH response is higher than of a febrile response

The present study was carried out to compare the threshold doses of interleukin-1 beta (IL-1 beta) necessary to elicit febrile and adrenocorticotrophic hormone (ACTH) responses. The results show that intravenous injection of a small dose of IL-1 beta (0.2 micrograms/kg) did not stimulate ACTH secretion but induced a significant febrile response. However, intravenous injection of a higher dose of IL-1 beta (2.0 micrograms/kg) induced significant increases in plasma ACTH accompanying the fever. These results suggest that the rise in body temperature per se is not responsible for the ACTH response and that the threshold dose of IL-1 beta to induce the ACTH response is higher than that to elicit the febrile response.

ACTH release induced in rats by noradrenaline is mediated by prostaglandin E2

1. We investigated the involvement of prostaglandin E2 in the development of the adrenocorticotrophic hormone (ACTH) response induced by noradrenaline (NA) in rats. 2. Intravenous (i.v.) injection of NA produced dose-dependent increases in the plasma concentration of ACTH and prostaglandin E2. However, pre-treatment with systemic administration of indomethacin, an inhibitor of prostaglandin synthesis, significantly suppressed this increase in plasma ACTH. 3. The i.v. injection of prostaglandin E2 significantly increased the plasma concentration of ACTH in a dose-dependent manner. In contrast, ACTH responses induced by the i.v. injection of prostaglandin E2 were significantly suppressed by systemic pre-treatment with anti-corticotrophin-releasing factor antibody (anti-CRF), although the plasma level of ACTH still increased in comparison to the basal level. 4. These results suggest that NA-stimulated prostaglandin release is involved in the ACTH response induced by NA. In addition, it is likely that CRF may be responsible for a portion of the ACTH response induced by i.v. injection of prostaglandin E2.

ACTH response in rats during biphasic fever induced by interleukin-1

Injection of a low concentration (0.3 micrograms/kg iv) of interleukin-1 beta (IL-1 beta) produced monophasic fever, but high concentrations (15 micrograms/kg iv) produced biphasic fever in rats. Treatment with IL-1 beta caused dose-dependent rises in the plasma concentration of adrenocorticotropic hormone (ACTH) 30 min after injection. Moreover, significant increases in plasma levels of ACTH were observed 90 and 180 min after injection of the high dose of IL-1 beta. ACTH response induced by IL-1 beta (15 micrograms/kg iv) was suppressed by pretreatment with injection of indomethacin (Indo), a potent inhibitor of prostaglandin (PG) synthesis, in a dose-dependent manner (1 and 10 mg/kg iv). Also, biphasic fever induced by the high dose of IL-1 beta was completely abolished by pretreatment with the intravenous injection of Indo. Intracerebroventricular (icv) injection of Indo (50 micrograms) did not affect febrile and ACTH responses induced by intravenous IL-1 beta, whereas those responses induced by IL-1 beta (2 ng icv) were significantly suppressed by injection of Indo (50 micrograms icv). Although it is possible that intracerebroventricular Indo does not reach the site of intravenous IL-1 beta action within the brain, these results suggest that in rats febrile and ACTH responses induced by intravenous IL-1 beta are caused by IL-1 beta-acting structures outside the blood-brain barrier. It is likely that these structures subsequently synthesize and release PGE2, which in turn induces ACTH and febrile responses in rats.

Possible involvement of prostaglandins in psychological stress-induced responses in rats

1. We investigated the effect of pre-treatment with intraperitoneal (I.P.) injection of indomethacin, an inhibitor of prostaglandin synthesis, on psychological stress-induced responses including cardiovascular, thermoregulatory and hormonal responses in free-moving rats. 2. Psychological stress was induced by cage-switch stress. After the rats were placed in the novel environment, blood pressure, heart rate and body temperature significantly increased. Plasma levels of adrenocorticotrophic hormone (ACTH) and prostaglandin E2 were significantly higher 30 min after exposure to stress, in comparison to normal levels. 3. Pre-treatment with I.P. indomethacin significantly suppressed the increases in body temperature induced by cage-switch stress, but had no effect on increases in blood pressure and heart rate induced by this stress. Indomethacin also significantly suppressed the increases in the plasma levels of ACTH and prostaglandin E2 induced by cage-switch stress. 4. The present results suggest that prostaglandins are involved in the development of hyperthermia and the ACTH response induced by psychological stress.