In vivo evidence that activation of tyrosine kinase is a trigger for lipopolysaccharide-induced fever in rats

We measured the rectal temperature of free-moving, conscious rats after intracerebroventricular (i.c.v.) injections of lipopolysaccharide (LPS) and interleukin-1beta (IL-1beta) with or without various antagonists to investigate the mechanisms involved in LPS-induced fever. LPS (3 microg) elicited significant increases in rectal temperature, which lasted from 0.5 h to more than 8 h after administration. This febrile response was inhibited by pretreatment with L-nitro-arginine (LNA), indomethacin (IND), genistein (GEN), tyrphostin 46 and anti-rat IL-1beta antibody (anti-IL-1beta Ab), but was not inhibited by pretreatment with daidzein or chelerythrine (CHE) into the ventricle. LPS (0.3 microg) following orthovanadate (i.c.v.) produced fever, although the small amount of LPS (0.3 microg) or orthovanadate alone showed no effect on rectal temperature. I.c.v. injections of IL-1beta also induced fever of approximately 4-h duration. This effect was inhibited by pretreatment with IND and anti-IL-1beta Ab, but was not inhibited by pretreatment with LNA, GEN or CHE into the ventricle. These findings demonstrate that in the central nervous system, LPS increases IL-1beta production after activation of tyrosine kinase and NO synthase, and IL-1beta promotes prostaglandin production resulting in increased rectal temperature. Activation of tyrosine kinase in the central nervous system is probably a trigger for the febrile response induced by LPS.

Expression of heparin-binding epidermal growth factor-like growth factor in the hepatocytes of fibrotic rat liver during hepatocarcinogenesis

BACKGROUND

Heparin-binding epidermal growth factor-like growth factor is an hepatotrophic factor expressed in non-parenchymal liver cells but not in hepatocytes in regenerating rat liver after partial hepatectomy. Human hepatocellular carcinoma cells also produce this growth factor. In this study, the expression of the growth factor in the hepatocytes of fibrotic liver during hepatocarcinogenesis was investigated.

METHODS

Hepatic fibrosis was induced in rats by oral administration of 0.05% thioacetamide. Hepatocytes were isolated by in situ perfusion methods. Growth factor gene and protein expression were investigated by northern hybridization and immunohistochemistry, respectively. Expression of glutathione s-transferase P, which is expressed when hepatocytes undergo neoplastic transformation, was also investigated.

RESULTS

Some hepatocytes in fibrotic liver, but not in normal liver, stained positively by immunohistochemistry for heparin-binding epidermal growth factor-like growth factor. The growth factor and glutathione s-transferase P gene transcript were present in hepatocytes isolated from fibrotic liver, but not in those isolated from normal liver. Immunohistochemical localization of both proteins in fibrotic liver revealed similar patterns.

CONCLUSIONS

In essence, hepatocytes in fibrotic rat liver produce heparin-binding epidermal growth factor-like growth factor. Expression of this growth factor may occur as hepatocytes are transformed to a neoplastic phenotype.

Effects of exogenous human heparin-binding epidermal growth factor-like growth factor on DNA synthesis of hepatocytes in normal mouse liver

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) has been reported to stimulate DNA synthesis of the hepatocytes in culture and highly express in regenerating rat liver after partial hepatectomy. We examined mitogenic effects and activation of transcription factors caused by exogenous human HB-EGF (hHB-EGF) in mouse liver. The mean labeling index in hepatocytes of hHB-EGF-injected mice was 2.6%, a significant increase over that in saline-injected controls (under 0.01%). By exogenous hHB-EGF injection, activation of transcription factors such as nuclear factor (NF)-kappaB and activator factor (AP)-1 was observed in the liver. By Northern blot analysis, hepatocyte growth factor (HGF) gene expression in the liver was found to be induced in the hHB-EGF-injected mice. In conclusion, intravenously injected hHB-EGF showed a limited but definite effect on the DNA synthesis of hepatocytes in the mice liver. HB-EGF may serve as a hepatotrophic factor in vivo.

Fas antigen (CD95) in pure erythroid cell line AS-E2 is induced by interferon-gamma and tumor necrosis factor-alpha and potentiates apoptotic death

We investigated the expression of Fas antigen (CD95) in the pure erythroid cell line AS-E2 in the presence and absence of interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). TNF-alpha induced apoptosis in AS-E2 cells, whereas IFN-gamma did not. In culture containing no IFN-gamma or TNF-alpha, AS-E2 cells expressed little Fas antigen. However, IFN-gamma and IFN-gamma and TNF-alpha both induced expression of Fas antigen and its mRNA within 24 hours after the stimulation. When anti-Fas monoclonal antibody (IgM) was added to AS-E2 cells after the induction of Fas expression, AS-E2 cells underwent apoptosis as shown by the induction of DNA fragmentation. This apoptotic change was inhibited by an inhibitor of caspase-3-like proteases (Ac-DEVD-CHO) and an inhibitor of CED-3/ICE family proteases (Z-Asp-CH2-DCB) but not by an inhibitor of caspase-1-like proteases (Ac-YVAD-CHO), suggesting a role for caspase-3-like proteases in Fas-receptor signaling. Although AS-E2 cells expressed Fas ligand mRNA, treatment with ZB4, an antibody that inhibits Fas-mediated cell death, failed to suppress IFN-gamma- or TNF-alpha-mediated cytotoxicity. These findings suggest that the late erythroid progenitor cells are negatively regulated by IFN-gamma and TNF-alpha, both of which are capable of inducing functional Fas expression.

Multi-clonal expansion of unique human T-lymphotropic virus type-I-infected T cells with high growth potential in response to interleukin-2 in prodromal phase of adult T cell leukemia

We established a simple IL-2-dependent colony-forming assay for T cells infected with human T-lymphotropic virus type-I (HTLV-I). IL-2-dependent cell lines were subsequently established by expanding individual colonies in liquid cultures. Lymphocyte-rich fractions were prepared from 31 HTLV-I carriers, 12 patients with smoldering ATL, 11 chronic ATL, 12 crisis ATL and 10 acute ATL. Primary colonies of CD4+ p19+ T cells were formed in all cases of carriers, smoldering and chronic ATL, and in 10 of 12 crisis cases. In contrast, no colony was formed from cells of patients with acute ATL. The rate of establishment of cell lines in HTLV-I carriers was significantly lower than that in patients of prodromal phase ATL. Cell lines established from cells of three prodromal cases were clonally identical to the parent ATL cells, while others had clonally distinct cell lines. Our results indicated the presence of four components of HTLV-I-infected T cells: (1) normal carrier T cells capable of forming colonies but not cell lines; (2) pre-malignant T cells capable of forming colonies as well as cell lines; (3) malignant T cells capable of forming colonies as well as cell lines; (4) fully malignant T cells unresponsive to IL-2. Our results suggest the presence of a multiclonal expansion of unique T cells in the prodromal phase of ATL, which have a high growth potential in response to IL-2. The coexistence of multiclonality with a dominant ATL clone may be closely related to the underlying pathology in HTLV-I leukemogenesis.

Central injections of capsaicin cause antidiuresis mediated through neurokinin-1 receptors in rat hypothalamus and vasopressin release

Intracerebroventricular injections of capsaicin at 100-500 nmol elicited dose-dependent decreases in urine outflow volume in anesthetized, hydrated rats. The capsaicin (500 nmol)-induced antidiuresis was inhibited by pretreatment with CP96345 (30 nmol, a neurokinin-1-receptor antagonist), but not by that with phenoxybenzamine (20 nmol, an alpha-adrenoceptor antagonist), timolol (100 nmol, a beta-adrenoceptor antagonist) or atropine (300 nmol, a muscarinic antagonist) into the hypothalamic supraoptic nucleus (SON). Intravenous injections of d(CH2)5-D-Tyr(Et)VAVP (50 microg/kg, a vasopressin-receptor antagonist) completely blocked the antidiuresis. In intra-SON microdialysis experiments, acetylcholine concentration in the perfusate of the capsaicin-injected rats was not different from that of the vehicle-injected rats. These findings suggested that capsaicin stimulated substance P release in the SON and caused the antidiuresis as a result of the increased release of vasopressin into the circulation from the neurohypophysis mediated through neurokinin-1 receptors in the SON.

Reduced plasma transforming growth factor-beta1 levels in patients with chronic hepatitis C after interferon-alpha therapy: association with regression of hepatic fibrosis

BACKGROUND/AIM

Transforming growth factor-beta1 is involved in liver fibrosis. Our aim was to examine the association of plasma transforming growth factor-beta1 levels with the degree of liver fibrosis.

METHODS

We analyzed plasma transforming growth factor-beta1 levels in 43 patients with chronic hepatitis C treated with interferon-alpha using a transforming growth factor-beta1 ELISA. The content of transforming growth factor-beta1 in liver tissue obtained by needle biopsy (n=13) was also analyzed. The degree of liver fibrosis was assessed histologically and morphometrically.

RESULTS

Plasma transforming growth factor-beta1 levels were significantly correlated with transforming growth factor-beta1 content in liver tissue (r=0.83, p<0.001), indicating that plasma levels correspond with tissue cytokine. Plasma transforming growth factor-beta1 levels in patients (8.1+/-1.1 ng/ml) before interferon-a therapy were significantly higher than in controls (1.9+/-0.3 ng/ml) (p<0.01). Plasma levels were significantly correlated with the degree of fibrosis (p<0.01). Plasma transforming growth factor-beta1 levels were significantly decreased in sustained responders (from 5.2+/-1.0 ng/ml to 2.9+/-0.7 ng/ml), relapsed patients (from 9.8+/-2.0 ng/ml to 3.4+/-0.6 ng/ml), and nonresponders (from 9.3+/-2.1 ng/ml to 3.9+/-0.9 ng/ml) at the end of therapy (p<0.05 for all comparisons). Significant regression of liver fibrosis after therapy was observed in both sustained responders and nonresponders (p<0.05 for both).

CONCLUSIONS

These observations suggest that plasma transforming growth factor-beta1 levels appear to be associated with the degree of liver fibrosis.

Individual variations in lymphocyte-responses to glucocorticoids in patients with bronchial asthma: comparison of potencies for five glucocorticoids

Glucocorticoids (GCs) are known to be effective for bronchial asthma, however, a considerable number of asthma patients fail to respond to GC despite the onset of serious side effects. Here we examined individual sensitivities to five clinically-used GCs in 40 asthma patients and 100 healthy subjects. Peripheral-blood mononuclear cells (PBMCs) were isolated from these subjects, and their in vitro sensitivities to hydrocortisone, prednisolone, methylprednisolone, dexamethasone, and betamethasone were determined with a mitogen-assay procedure. The number of PBMCs positive to IL-2 receptors (IL-2Rs) as well as soluble IL-2R (sIL-2R) levels in serum were concomitantly measured in asthma patients, and relationships between these cytokine indices and PBMC-sensitivities to GCs were also examined. Large individual variations in GC IC50s have been observed in PBMCs from asthma subjects, especially in prednisolone IC50s (ranged from 1 to 10,000 ng/ml). When compared with healthy subjects, asthma patients tend to show PBMC-resistance to prednisolone (p < 0.05). Moreover, potencies of methylprednisolone on PBMC-blastogenesis were > 10 times higher than those of prednisolone in both healthy subjects and asthmatics (p < 0.01). In asthma patients, IC50s of hydrocortisone, prednisolone and betamethasone against PBMC-blastogenesis were significantly correlated with elevated percentages of IL-2R-positive PBMCs (p < 0.05), while the IC50 of methylprednisolone showed no such correlation. sIL-2R levels did not correlate with IC50s of any of the GCs examined. Thus, the results showed that a part of asthma patients exhibited PBMC-resistance to GCs, especially to prednisolone. Methylprednisolone potency was unexpectedly higher (> 10 times) than prednisolone potency. Our results also raised the possibility that PBMC-resistance to prednisolone in asthma may correlate with an increase in IL-2R positive PBMCs.

Human erythropoietin receptor increases GATA-2 and Bcl-xL by a protein kinase C-dependent pathway in human erythropoietin-dependent cell line AS-E2

Erythropoietin (Epo) is a cytokine known to stimulate proliferation and differentiation of erythroid cells. However, recent gene disruption experiments demonstrated that Epo receptor signaling is not an obligatory step in erythroid differentiation. Here, we describe the role of Epo in proliferation, terminal differentiation, and apoptosis in a novel human Epo-dependent cell line, AS-E2. Upon withdrawal of Epo, the cells ceased to proliferate and underwent apoptotic death. Accompanying this cell death, an increase in the number of hemoglobin-positive cells of approximately 2-fold was observed. This was associated with immediate up-regulation of the GATA-1:GATA-2 ratio and down-regulation of Bcl-xL. Treatment with Epo or 12-O-tetradecanoyl-phorbol-13-acetate (TPA) up-regulated expression of GATA-2 and Bcl-xL, and these elevations were inhibited by inhibitors of protein kinase C (PKC), H7 and H8. HA1004, a structural analogue of H7 but a poor inhibitor of PKC, had no inhibitory effect. Therefore, in AS-E2 cells, it is likely that Epo plays a role in (a) proliferation, (b) inhibition of differentiation, and (c) survival, by maintaining GATA-2 and Bcl-xL expression through activation of PKC.

Establishment and characterization of a new erythropoietin-dependent acute myeloid leukemia cell line, AS-E2

We have established an erythropoietin-dependent human leukemia cell line, AS-E2, from a patient with acute myeloid leukemia. These cells have many characteristics of late erythroid progenitor cells, they are positive for CD36, Glycophorin A, and CD71 but negative for CD41, and positive for benzidine and PAS staining. These cells express GATA-1 and have low affinity erythropoietin (EPO) receptor on their surface. Interestingly, AS-E2 cells are strictly dependent on EPO for their growth and survival; other cytokines including GM-CSF, stem cell factor, or IL-3 cannot support the growth of this cell line. These features are similar to late erythroid lineage cells, like normal BFU-E or CFU-E, and we have demonstrated that EPO stimulation induces the tyrosine phosphorylation of several proteins in AS-E2 cells including the EPO receptor and JAK2 kinase. This new cell line is a useful reagent to study biological and molecular events during the late stages of erythropoiesis, and to understand transforming events in human erythroid cells.

Central regulation of urine production by a selective mu-opioid agonist, [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin, in rats

We have investigated opioid mechanisms concerning regulation of urine production in the hypothalamic supraoptic nucleus (SON). In this study, the effect of [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO), a potent selective mu-opioid agonist, microinjected into the SON of anesthetized hydrated rats, on the urine outflow rate was examined. DAMGO caused a dose-dependent decrease in the urine outflow rate with no significant changes in blood pressure nor heart rate. The ED50 value for the antidiuresis was calculated to be 0.055 nmol from the dose-response curve. The antidiuresis elicited by DAMGO (0.1 nmol) was partially inhibited by intra-SON pre-injection of naloxone (3 nmol), a relatively mu-selective opioid antagonist, and timolol (100 nmol), a beta-adrenoceptor antagonist, but not by intra-SON pre-injection of phenoxybenzamine (20 nmol), an alpha-adrenoceptor antagonist, nor atropine (300 nmol), a muscarinic antagonist. Intravenous injection of d(CH2)5-D-Tyr(Et)VAVP (16.7 micrograms), a vasopressin receptor antagonist, did not influence the DAMGO-induced antidiuresis. These findings suggest that antidiuresis mediated through mu-opioid receptors in the SON involves beta-adrenoceptors in the nuclei, but does not involve an increase in vasopressin release.

alpha-adrenoceptor subtype in the hypothalamic paraventricular nucleus involved in the regulation of urine production: comparison between Wistar Kyoto and spontaneously hypertensive rats

Microinjections of alpha-adrenoceptor agonists into the paraventricular nucleus (PVN) of Wistar Kyoto rats (WKY) decreased the urine outflow rate in dose- and time-dependent manners. The order of the antidiuretic potency is norepinephrine (an alpha-agonist) > phenylephrine (an alpha 1-agonist) > > clonidine (an alpha 2-agonist). The phenylephrine-induced effect was inhibited by WB4101 (an alpha 1-antagonist), but not by yohimbine (an alpha 2-antagonist). d(CH2)5-D-Tyr(Et)VAVP (a vasopressin antagonist) blocked the antidiuretic effect of phenylephrine. In spontaneously hypertensive rats (SHR), norepinephrine and phenylephrine produced weaker antidiuretic effects than in WKY. These findings suggest that the alpha 1-subtype of the PVN decreases urine production mediated through vasopressin release. This mechanism is more feeble in SHR than WKY.

Integration patterns of HTLV-I provirus in relation to the clinical course of ATL: frequent clonal change at crisis from indolent disease

We examined human T-lymphotropic virus type I (HTLV-I) DNA integration in 68 patients with adult T-cell leukemia/ lymphoma (ATL) by Southern blotting using EcoRI, which does not cut within the 9 kb of the genome and probes for pX and gag-pol region of HTLV-I. We detected defective proviral integration as a monoclonal band of various sizes with the pX but not with the gag-pol probe, or a monoclonal band of less than 9 kb with the pX probe, in 20 patients (29.4%). These were designated defective (D) type. With both probes, a single band greater than 9 kb was detected in 34 (50.0%), designated complete (C) type, and two or more bands greater than 9 kb, were designated multiple (M) type, in 14 (20.6%). Advanced age, a high LDH value, and hypercalcemia were more frequent in D type patients. The median survival time (MST) was 6.8, 24.4, and 33.3 months, for D, C, and M types, respectively (log rank P = .006). Among 52 sequentially examined patients, the HTLV-I integration patterns changed in 4 (7.5%). In three of these four, the rearrangements of the T-cell receptor (TCR)b gene concomitantly changed, suggesting the appearance of a new ATL clone. Another patient had the same rearrangement of the TCRb gene, indicating clonal evolution. The HTLV-I integration pattern changed at crisis from indolent to aggressive ATL in three patients. These findings suggested that the HTLV-I integration patterns have clinical implications in ATL pathophysiology. In contrast to the clonal evolution characteristic of the multistep carcinogenesis of most human malignancies, the frequent clonal change of ATL at crisis is a peculiar phenomenon, probably reflecting the emergence of multiple premalignant clones in viral leukemogenesis as suggested in Epstein-Barr virus associated lymphomagenesis in the immunocompromised host.

Efficacy of combination therapy of interferon-alpha with ursodeoxycholic acid in chronic hepatitis C: a randomized controlled clinical trial

The efficacy of interferon-alpha therapy in the treatment of chronic hepatitis C is still limited. A combination therapy of interferon-alpha with ursodeoxycholic acid (UDCA) was tested for its efficacy in the treatment of chronic hepatitis C by a randomized controlled study. Eighty consecutive Japanese patients with chronic hepatitis C were randomly divided into two groups: one group was treated with interferon-alpha (group A, n = 40) and the other with a combination of interferon-alpha and UDCA (group B, n = 40). In both groups, human interferon-alpha (6 million units per day) was intramuscularly injected daily for 2 weeks and then three times a week for 22 weeks: this 24-week period was followed by 24 weeks of observation. In group B, UDCA was also administered, daily at a dose of 600 mg orally, from the beginning of the interferon therapy and administration was continued for 48 weeks. The rates for ALT normalization and clearance of hepatitis C virus (HCV) viremia at the end of the 24-week interferon therapy were similar for groups A and B (58% vs 60% and 55% vs 48%, respectively). At the end of the 24-week follow-up, the sustained normalization rates for ALT levels for the two groups were not different (35% vs 43%), while the rate of clearance was higher in group B (40%) than in group A (23%), but the difference was not significant (P = 0.14). The sustained complete response, i.e., HCV RNA negativity at the end of the follow-up, as well as the maintenance of ALT normalization during the follow-up period, was more frequent in group B (38%) than in group A (18%) although the difference was not significant (P = 0.08). The rate of HCV reactivation after interferon was discontinued was significantly lower in group B (16%) than in group A (59%) (P < 0.01). Although this combination therapy did not lead to a sufficiently sustained complete response, it could serve as adjuvant antiviral therapy when a suitable dosage and administration period are determined.

Increased circulating transforming growth factor beta1 in a patient with giant hepatic hemangioma: possible contribution to an impaired immune function

A patient, having a huge hepatic hemangioma, presented with decreases in the number of peripheral lymphocytes and in serum concentrations of gamma-globulin and immunoglobulin (Ig) G, and a negative purified protein derivatives skin test, indicating that the patient's immunity was impaired. The plasma concentration of transforming growth factor beta1 (TGF-beta1), a potent immunosuppressor, in the patient was markedly elevated (113 ng/mL, normal < 5). After the surgical removal of the tumor, the plasma TGF-beta1 concentration decreased, and the patient's immunity was restored to normal. Northern blot analysis showed an overexpression of the TGF-beta1 gene in the hemangioma tissue, while normal control liver tissue expressed undetectable levels of TGF-beta1 messenger RNA. These results suggest that the elevated levels of TGF-beta1 in the plasma were derived from the giant hemangioma tissue and may have contributed to the impaired immune function in the patient.

Isolation and amino acid sequence of a cystatin-type cysteine proteinase inhibitor from bovine hoof

A low molecular mass cysteine proteinase inhibitor was found and isolated from bovine hoof. Purification of the inhibitor to homogeneity was performed by carboxymethyl-papain-sepharose affinity and DE-52 ion exchange chromatographies. From 15 g of bovine hoof, 0.25 mg of cysteine proteinase inhibitor was isolated. It had 100 amino acid residues and molecular mass of 11 406 Da, and its N-terminus was blocked. The amino acid sequence of the inhibitor demonstrated high similarity with that of the family 1 group, especially bovine thymus-derived cystatin. Thus, in summary, bovine hoof contains a cystatin-type cysteine proteinase inhibitor, presumably a family 1 cystatin.

Diagnostic criteria for hypocellular acute leukemia: a clinical entity distinct from overt acute leukemia and myelodysplastic syndrome

In order to establish diagnostic criteria for hypocellular acute leukemia (HL), we have reviewed 32 cases selected on the basis of hypothetical 40% or less cellularity, by focusing on morphology, immunophenotype, karyotype and response to low dose Ara-C (LDAC) regimen and compared them with 40 cases of myelodysplastic syndrome (MDS) and 66 cases of overt acute myeloid leukemia (AML). The onset age ranged from 44 to 75 years (median 67 years). Bone marrow (BM) cellularity ranged from 12.4 to 39.8% (mean 29.8%) in HL, being significantly lower than in MDS (mean 80.7%) or AML (mean 86.4%) (P < 0.001). All reviewed cases characteristically showed smoldering clinical course, bi- or pancytopenia with rare leukemic blasts in the peripheral blood (PB), proliferation of type I leukemic blasts in the BM and markedly reduced background hematopoietic cells with some dysplastic changes in 12/32 cases (37.50/6). Blast percentage (blast %) in the BM ranged from 38.2 to 93.7% (mean 57.3%) in all nucleated cells (ANC). Although a considerable number of cases had blasts with negative or very low myeloperoxidase activity, immunophenotyping revealed that the leukemic blasts in HL had only myeloid markers. Karyotyping revealed non-random chromosome abnormalities in 30% of cases analyzed, which were considerably different from those seen in MDS. With LDAC regimen, a significantly higher CR rate (13/20 cases: 65.0%) was gained in HL than in RAEB/RAEB-t (0%) and overt AML in the elderly cases (27.3%) (P < 0.05). In CR, most cases showed recovery to normocellular BM with an apparent normalization of PB parameters. However, 12 CR cases relapsed 4-12 months later; most of which again showed hypocellular BM. These results indicate that HL is a distinct subtype of AML characterized by slow but distinct proliferation of immature myeloid blasts and by unique hematological features distinct from MDS or overt AML in the elderly. We propose the following diagnostic criteria: (1) pancytopenia with rare appearance of blasts in PB; (2) less than 40% BM hypocellularity; (3) more than 30% blasts in BM-ANC; and (4) myeloid phenotypes of leukemic blasts by MPO staining and/or immunophenotyping.

Long exposure to high glucose concentration impairs the responsive expression of gamma-glutamylcysteine synthetase by interleukin-1beta and tumor necrosis factor-alpha in mouse endothelial cells

To elucidate the pathological metabolism of glutathione synthesis in diabetic endothelial cells, we studied the expression of gamma-glutamylcysteine synthetase (gamma-GCS) using a mouse vascular endothelial cell line. Exposing normoglycemic endothelial cells to tumor necrosis factor-alpha (TNF-alpha) or interleukin-1beta (IL-1beta) increased the activity and the mRNA expression of gamma-GCS. The addition of inhibitors for nuclear factor kappaB (NF-kappaB) to the cells caused a loss of the gamma-GCS mRNA expression in response to TNF-alpha. A shift of the concentration of glucose in the medium from 5.5 to 28 mM glucose and a following incubation for 7 days decreased the expression of gamma-GCS mRNA. These cells showed no apparent responses of gamma-GCS mRNA or the activity of NF-kappaB to TNF-alpha or IL-beta. Increase in the GSH concentration of the cells treated with 28 mM glucose restored the expression of gamma-GCS mRNA and its response to TNF-alpha or IL-beta, suggesting that redox regulation is involved in the expression of gamma-GCS. In summary, the expression of gamma-GCS is regulated by TNF-alpha or IL-1beta in endothelial cells mediated by NF-kappaB stimulation, and impairment of the regulation of gamma-GCS in hyperglycemic cells may be a cause of medical complications that develop in diabetes mellitus.

The effect of hepatitis B virus X gene expression on response to growth inhibition by transforming growth factor-beta 1

Hepatitis B virus X protein (HBx protein), which seems to be involved in hepatocarcinogenesis, was studied for its effect on cell growth regulation. We examined the response to growth inhibition of transforming growth factor beta 1 (TGF-beta 1) in HBx gene-introduced cells. HBx gene in pRc/CMV was transfected to mink lung epithelial cells (Mv1Lu cells) and a stable transformant was obtained. The inhibition rates of [3H] thymidine incorporation by addition of TGF-beta 1 (0.08 ng/ml) to parent cells and pRc/CMV-transfected cells were 34% and 26%, respectively. However, the inhibition rates in the HBx gene-transfected cells were 3-8%. The amount of TGF-beta type II receptor on the surface of HBx gene-transfected cells was about half of that on the parent or pRc/CMV-transfected cells. Our results indicated that expression of HBx gene reduces the response to growth inhibition by TGF-beta 1.

Peptidase inhibitor-induced antidiuresis mediated through angiotensin and opioid receptors in the rat hypothalamus

We examined the effects on urine outflow rate after microinjections of thiorphan (a carboxypeptidase inhibitor) and bestatin (an aminopeptidase inhibitor) into the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei of anesthetized hydrated rats to determine the possible role of neuropeptides in the regulation of urine production. After individual microinjection of the peptidase inhibitors into the nuclei, only thiorphan at 100 nmol administered into the PVN significantly decreased the urine outflow rate. Two consecutive microinjections of the peptidase inhibitors at 100 nmol each into the nuclei induced potent antidiuresis. These effects after microinjections of the peptidase inhibitors into the PVN and SON were diminished by pretreatment with [Sar1,Ile8]angiotensin (ANG) II (an ANG II receptor antagonist) and naloxone (an opioid receptor antagonist) in the PVN and with [Sar1,Ile8]ANG II in the SON, respectively. A vasopressin (AVP) receptor antagonist, d(CH2)5-D-Tyr(Et)VAVP (i.v.), completely blocked the antidiuresis by microinjections of the peptidase inhibitors into both the nuclei. Urinary osmotic pressure was significantly increased by consecutive microinjections of the peptidase inhibitors into the PVN and SON. These results suggest that endogenously-released ANG II and opioid peptides in the PVN and ANG II in the SON regulate urine production mediated through increased AVP release.

Adrenergic neural connections between the bilateral supraoptic nuclei of the rat hypothalamus

Our previous study has demonstrated that unilateral microinjection of norepinephrine (NE) into the right supraoptic nucleus (SON) of anesthetized hydrated rats elicited dose-dependent decreases in the urine outflow rate. This was antagonized by pretreatment with phenoxybenzamine (an alpha-antagonist) and timolol (a beta-antagonist) in the same SON. In the present study, we examined the effects of NE, microinjected into the right, left and bilateral SON, on the urine outflow rate in order to investigate neural connections between the bilateral SON. NE administered by those three routes dose-dependently decreased the urine outflow rate. The order for the antidiuretic potency was as follows: the effect elicited by the intrabilateral-SON microinjection > the intra-left-SON microinjection = the intra-right-SON microinjection. The antidiuresis of NE microinjected into the right SON was inhibited by an electrolytic left-SON lesion and by pretreatment with phenoxybenzamine (20 nmol) and timolol (100 nmol), but not by atropine (300 nmol) in the left SON. These findings suggest adrenergic neural connections from the right to left SON, contributing to the regulation of urine production. Furthermore, there is a possibility that stimulation of endogenously-released NE in the bilateral SON is amplified through these neurons and elicits more potent effects than those produced in either the right or left nucleus.

Induction of interleukin-6 by interferon alfa and its abrogation by a serine protease inhibitor in patients with chronic hepatitis C

We investigated short-term alterations in plasma interleukin-6 (IL-6), interleukin-1beta (IL-1beta), and tumor necrosis factor alpha (TNF-alpha) levels induced by interferon alfa (IFN-alpha) injection in 18 patients with chronic hepatitis C. A single intramuscular injection of human recombinant IFN-alpha 2a (6 million units [MU]) significantly increased the plasma IL-6 level 6 hours after the injection (P < .05). On the other hand, the IFN-alpha injection did not affect the plasma TNF-alpha and IL-lbeta levels. Polymerase chain reaction (PCR) analysis showed accumulation of IL-6 gene transcripts in peripheral blood mononuclear cells (PBMC) after IFN-alpha injection, indicating that IFN-alpha enhances IL-6 production at the messenger RNA level. The induction of IL-6 by IFN-alpha was completely suppressed by the intravenous administration of gabexate mesilate (GM), a serine protease inhibitor. The mechanism whereby GM suppresses the elevation in circulating IL-6 levels seems to be the inhibition of IL-6 production at the messenger RNA level. Elevations of both serum C-reactive protein (CRP) levels and body temperature after GM-suppressed IFN-alpha injection suggest that the administration of GM by suppressing IL-6 production, may attenuate the IL-6-related responses induced by IFN-alpha injection. In conclusion, we found that IL-6 was induced by IFN-alpha in vivo, and that this induction was completely abrogated by the administration of GM. Our results indicate that serine protease inhibitors may be useful for inhibiting IL-6-relating responses.