Biomedical subjects

G Inoue

Publications and source records attributed to G Inoue.

At least 19 recordsLinked to original sources

PubMed2002

Clinical implications of leptin and its potential humoral regulators in long-term low-calorie diet therapy for obese humans.

OBJECTIVE: To address the clinical implications of leptin and to re-examine the relationship between leptin and its potential humoral regulators such as insulin, nonesterified fatty acids (NEFA) and triiodothyronine (T3) in low-calorie diet (LCD) for obese humans. DESIGN: Longitudinal study. SETTING: University and foundation hospitals. SUBJECTS: Ten obese men and 10 premenopausal obese women. INTERVENTIONS: Five men and five women took 800 kcal/day LCD and another five men and five women took 1400 kcal/day balanced deficit diet (BDD) during 4 weeks. RESULTS: Plasma leptin levels in the LCD group decreased more markedly (46.2+/-14.6 to 13.2+/-3.6 ng/ml) than that expected for the decrement in percentage fat (39.0+/-1.7 to 35.9+/-1.7%) and body mass index (BMI; 35.4+/-2.4 to 33.1+/-2.2 kg/m(2)), while that in the BDD group did not decrease significantly (14.9+/-3.5 to 13.4+/-2.8 ng/ml). The ratio of the decrease in leptin levels to that of BMI during the first week was significantly greater than that during the following 3 weeks (39.5+/-2.7 vs 29.3+/-2.1%, P=0.017). The plasma insulin and T3 levels also fell substantially in the first week and continued to decrease during the entire course. Plasma leptin levels measured weekly in each subject were correlated well with insulin (r=0.586, P=0.0003) and T3 (r=0.785, P=0.0004). Multiple regression analyses after adjustment for the time course and BMI revealed that serum levels of T3 were independently correlated with plasma leptin levels (r=0.928, P<0.0001). The plasma NEFA level was markedly elevated during the first 2 weeks and decreased thereafter. CONCLUSIONS: A rapid fall in leptin during the first week of LCD, coordinated by insulin, T3 and NEFA, should be beneficial for responding to decreased energy intake. Inversely, in view of the powerful effect of leptin on energy dissipation, the present findings suggest the potential usefulness of leptin in combination with caloric restriction for the treatment of obesity. SPONSORSHIP: The Ministry of Education, Culture, Sports, Science and Technology of Japan and the Ministry of Health, Labour and Welfare of Japan.

Adolescent↗

PubMed2001

Shock wave application to rat skin induces degeneration and reinnervation of sensory nerve fibres.

There have been several reports on the use of extracorporeal shock waves in the treatment of pseudarthrosis, calcifying tendinitis, and tendinopathies of the elbow. However, the pathomechanism of pain relief has not been clarified. To investigate the analgesic properties of shock wave application, we analyzed whether it produces morphologic changes in cutaneous nerve fibres. In normal rat skin, the epidermis is heavily innervated by nerve fibres immunoreactive for protein gene product (PGP) 9.5 and by some fibres immunoreactive for calcitonin gene-related peptide (CGRP). There was nearly complete degeneration of epidermal nerve fibres in the shock wave-treated skin, as indicated by the loss of immunoreactivity for PGP 9.5 or CGRP. Reinnervation of the epidermis occurred 2 weeks after treatment. These data show that relief of pain after shock wave application to the skin results from rapid degeneration of the intracutaneous nerve fibres.

Animals↗

PubMed2001

Periscapho-lunate dislocation.

A case of a volar periscapholunate dislocation is reported. Treatment by closed reduction and Kirschner wire fixation gave a good clinical result.

Accidental Falls↗

PubMed2001

Surgical treatment for recurrent dislocation of the extensor carpi ulnaris tendon.

Twelve patients with recurrent dislocation of the extensor carpi ulnaris tendon were treated with repair or reconstruction of its tendon sheath, and each had a satisfactory result. We found three types of disruption of the fibro-osseous sheath. Type A: the fibro-osseous sheath ruptured ulnarly and the torn sheath lay superficial to the tendon (n=5). These were treated by reconstruction of the sheath using a piece of the extensor retinaculum. Type B: the fibro-osseous sheath ruptured radially and the torn sheath lay in the ulnar groove beneath the tendon (n=3). These were treated by direct suture of the sheath over the tendon. Type C: detachment of the periosteum from the ulnar side of the ulna in continuity with the fibro-osseous sheath formed a false pouch into which the tendon easily dislocated (n=4). These were treated by reattachment of the periosteum.

Adult↗

PubMed2001

Up-regulation of uncoupling protein 3 gene expression by fatty acids and agonists for PPARs in L6 myotubes.

Uncoupling protein 3 (UCP3), which uncouples electron transport from ATP synthesis, is expressed at high levels in the skeletal muscle, an important organ in glucose and lipid metabolism. Because several reports proposed that fatty acids induced UCP3 gene expression in skeletal muscle in vivo, in the present study we examined the regulation of UCP3 gene expression by various fatty acids using L6 myotubes. UCP3 gene expression was increased in L6 myotubes by various fatty acids or by alpha-bromopalmitate, a nonmetabolized derivative of palmitic acid. Because fatty acids are also known as agonists for PPARs, we examined the involvement of PPARs in the regulation of the UCP3 gene expression. L-165041, a PPAR delta agonist, increased UCP3 gene expression in L6 myotubes, whereas neither Wy 14,643, a PPAR alpha agonist, nor Pioglitazone, a PPAR gamma agonist, increased it. Therefore, we conclude that UCP3 gene expression is increased by the activation of PPAR delta in L6 myotubes and postulate that PPAR delta mediates at least some part of the increased UCP3 gene expression by fatty acids in skeletal muscle in vivo.

Animals↗

PubMed2001

Simultaneous onset of type 1 diabetes mellitus and painless thyroiditis following acute pancreatitis.

A 24-year-old female suffered from acute pancreatitis, followed by simultaneous onset of painless goiter, elevation of thyroid hormones and diabetic ketoacidosis. Two months later, her insulin secreting function was severely decreased and positive for anti-GAD and anti-islet cell antibodies, whereas the serum glucagon level was normal, suggesting an autoimmune-related destruction specifically of beta cells. In addition, the initial hyperthyroid state was followed by a hypothyroid phase which later recovered to an euthyroid state, suggesting an initial destruction of thyroid cells. Because anti-thyroidal antibodies were positive, it is likely that the thyroidal destruction was also autoimmune-related. This case implies common pathogenic mechanisms in the autoimmunity related destruction of beta cells and thyroid cells.

Acute Disease↗

PubMed2001

Troglitazone not only increases GLUT4 but also induces its translocation in rat adipocytes.

Thiazolidinediones, insulin-sensitizing agents, have been reported to increase glucose uptake along with the expression of glucose transporters in adipocytes and cardiomyocytes. Recently, we have further suggested that the translocation of GLUT4 is stimulated by thiazolidinediones in L6 myocytes. However, the direct effects of thiazolidinediones on translocation of glucose transporters have not yet been determined. In this study, using hemagglutinin epitope-tagged GLUT4 (GLUT4-HA), we provide direct evidence of the effect of troglitazone on the translocation of GLUT4 in rat epididymal adipocytes. Primary cultures of rat adipocytes were transiently transfected with GLUT4-HA and overexpressed eightfold compared with endogenous GLUT4 in transfected cells. A total of 24 h of treatment with troglitazone (10(-4) mol/l) increased the cell surface level of GLUT4-HA by 1.5 +/- 0.03-fold (P < 0.01) without changing the total amount of GLUT4-HA, whereas it increased the protein level of endogenous GLUT4 (1.4-fold) without changing that of GLUT1. Thus, the direct effect on the translocation can be detected apart from the increase in endogenous GLUT4 content using GLUT4-HA. Troglitazone not only increased the translocation of GLUT4-HA on the cell surface in the basal state but also caused a leftward shift in the dose-response relations between GLUT4-HA translocation and insulin concentration in the medium (ED(50): from approximately 0.1 to 0.03 nmol/l). These effects may partly contribute to the antidiabetic activity of troglitazone in patients with obesity and type 2 diabetes.

Adipocytes↗

PubMed2001

Ghrelin, an endogenous growth hormone secretagogue, is a novel orexigenic peptide that antagonizes leptin action through the activation of hypothalamic neuropeptide Y/Y1 receptor pathway.

Ghrelin, an endogenous ligand for growth hormone secretagogue (GHS) receptor originally isolated from the stomach, occurs in the hypothalamic arcuate nucleus and may play a role in energy homeostasis. Synthetic GHSs have activated the hypothalamic arcuate neurons containing neuropeptide Y (NPY), suggesting the involvement of NPY in some of ghrelin actions. This study was designed to elucidate the role of ghrelin in the regulation of food intake. A single intracerebroventricular (ICV) injection of ghrelin (5-5,000 ng/rat) caused a significant and dose-related increase in cumulative food intake in rats. Ghrelin (500 ng/rat) was also effective in growth hormone-deficient spontaneous dwarf rats. Hypothalamic NPY mRNA expression was increased in rats that received a single ICV injection of ghrelin (500 ng/rat) (approximately 160% of that in vehicle-treated groups, P < 0.05). The ghrelin's orexigenic effect was abolished dose-dependently by ICV co-injection of NPY Y1 receptor antagonist (10-30 microg/rat). The leptin-induced inhibition of food intake was reversed by ICV co-injection of ghrelin in a dose-dependent manner (5-500 ng/rat). Leptin reduced hypothalamic NPY mRNA expression by 35% (P < 0.05), which was abolished by ICV co-injection of ghrelin (500 ng/rat). This study provides evidence that ghrelin is an orexigenic peptide that antagonizes leptin action through the activation of hypothalamic NPY/Y1 receptor pathway.

Animals↗

PubMed2001

Troglitazone induces GLUT4 translocation in L6 myotubes.

A number of studies have demonstrated that insulin resistance in the skeletal muscle plays a pivotal role in the insulin resistance associated with obesity and type 2 diabetes. A decrease in GLUT4 translocation from the intracellular pool to the plasma membranes in skeletal muscles has been implicated as a possible cause of insulin resistance. Herein, we examined the effects of an insulin-sensitizing drug, troglitazone (TGZ), on glucose uptake and the translocation of GLUT4 in L6 myotubes. The prolonged exposure (24 h) of L6 myotubes to TGZ (10(-5) mol/l) caused a substantial increase in the 2-deoxy-[3H]D-glucose (2-DG) uptake without changing the total amount of the glucose transporters GLUT4, GLUT1, and GLUT3. The TGZ-induced 2-DG uptake was completely abolished by cytochalasin-B (10 micromol/l). The ability of TGZ to translocate GLUT4 from light microsomes to the crude plasma membranes was greater than that of insulin. Both cycloheximide treatment (3.5 x 10(-6) mol/l) and the removal of TGZ by washing reversed the 2-DG uptake to the basal level. Moreover, insulin did not enhance the TGZ-induced 2-DG uptake additively. The TGZ-induced 2-DG uptake was only partially reversed by wortmannin to 80%, and TGZ did not change the expression and the phosphorylation of protein kinase B; the expression of protein kinase C (PKC)-lambda, PKC-beta2, and PKC-zeta; or 5'AMP-activated protein kinase activity. a-Tocopherol, which has a molecular structure similar to that of TGZ, did not increase 2-DG uptake. We conclude that the glucose transport in L6 myotubes exposed to TGZ for 24 h is the result of an increased translocation of GLUT4. The present results imply that the effects of troglitazone on GLUT4 translocation may include a new mechanism for improving glucose transport in skeletal muscle.

Animals↗

PubMed2001

Transgenic overexpression of leptin rescues insulin resistance and diabetes in a mouse model of lipoatrophic diabetes.

Lipoatrophic diabetes is caused by a deficiency of adipose tissue and is characterized by severe insulin resistance, hypoleptinemia, and hyperphagia. The A-ZIP/F-1 mouse (A-ZIPTg/+) is a model of severe lipoatrophic diabetes and is insulin resistant, hypoleptinemic, hyperphagic, and shows severe hepatic steatosis. We have also produced transgenic "skinny" mice that have hepatic overexpression of leptin (LepTg/+) and no adipocyte triglyceride stores, and are hypophagic and show increased insulin sensitivity. To explore the pathophysiological and therapeutic roles of leptin in lipoatrophic diabetes, we crossed LepTg/+ and A-ZIPTg/+ mice, producing doubly transgenic mice (LepTg/+:A-ZIPTg/+) virtually lacking adipose tissue but having greatly elevated leptin levels. The LepTg/+:A-ZIPTg/+ mice were hypophagic and showed improved hepatic steatosis. Glucose and insulin tolerance tests revealed increased insulin sensitivity, comparable to LepTg/+ mice. These effects were stable over at least 6 months of age. Pair-feeding the A-ZIPTg/+ mice to the amount of food consumed by LepTg/+:A-ZIPTg/+ mice did not improve their insulin resistance, diabetes, or hepatic steatosis, demonstrating that the beneficial effects of leptin were not due to the decreased food intake. Continuous leptin administration that elevates plasma leptin concentrations to those of LepTg/+:A-ZIPTg/+ mice also effectively improved hepatic steatosis and the disorder of glucose and lipid metabolism in A-ZIP/F-1 mice. These data demonstrate that leptin can improve the insulin resistance and diabetes of a mouse model of severe lipoatrophic diabetes, suggesting that leptin may be therapeutically useful in the long-term treatment of lipoatrophic diabetes.

Animals↗

PubMed2001

The CD81 expression in liver in hepatocellular carcinoma.

The expression of CD81, a cell receptor for hepatitis C virus, was examined on cancer cells in hepatocellular carcinoma (HCC) C (n=29) to clarify its clinical role. CD81 was expressed on hepatocyte membrane in non-tumor portions in all patients, however, this was not stained on the cancer cell membranes in 6 of 29. Reverse transcriptase-PCR revealed that CD81 gene expression was not detected in the tumorous portions in 3 of 7 samples. The loss of CD81 was prominent in poorly differentiated HCC (5 of 8) and extrahepatic metastasis patients (6 of 8). The loss of CD81 is associated with differentiation and metastasis of HCC.

Aged↗

PubMed2000

Effect of interleukin-10 (IL-10) on experimental LPS-induced acute lung injury.

The purpose of this study was to clarify the role of interleukin-10 (IL-10) during the development of acute lung injury induced by lipopolysaccharide (LPS) in a mouse model. When LPS was given to nude mice, the mortality rate was 100% at 48 h of the observation period. However, mortality was reduced to 30% when IL-10 was added concomitantly (P < 0.01). In the IL-10 group, a significant reduction of inflammatory change in lung tissue was observed. It was also found that peripheral neutrophils increased when IL-10 was added. When LPS and IL-10 were given concomitantly, the level of tumor necrosis factor (TNF)-alpha in both serum and bronchoalveolar lavage fluid (BALF) decreased significantly (P < 0.05). In-vitro observations were made concerning the influence of human neutrophils. Both neutrophil superoxide (O2-) and elastase production were increased by TNF-alpha stimulation, while significant inhibition was seen with the concomitant dosing of IL-10 (P < 0.05). TNF-alpha stimulation increased the occurrence of adhesion molecules for neutrophil surface, lymphocyte function-associated antigen-1 (LFA-1), and macrophage antigen-1 (Mac-1). LPS stimulation greatly increased the occurrence of neutrophil surface 55-kDa TNF-receptor [TNF-R (p55)], when observation was made under laser microscopy. However, no significant occurrence was seen with IL-10 concomitant dosing. The above results suggested that IL-10 inhibited TNF-alpha production and neutrophil activity in LPS-induced acute lung injury, which led to a reduction of the lung tissue injury.

Animals↗

PubMed2000

Downregulation of leptin by free fatty acids in rat adipocytes: effects of triacsin C, palmitate, and 2-bromopalmitate.

Free fatty acid (FFA) has been reported to decrease leptin mRNA levels in 3T3-L1 adipocytes. When using this cell line, it is difficult to determine the protein levels because a very small amount of leptin is secreted into the medium. The effect of FFA on leptin secretion from adipocytes has not yet been determined. In addition, in vivo studies have failed to demonstrate a FFA-induced decrease in plasma leptin levels. To clarify the effect of FFA on leptin production, we investigated the leptin protein level in the medium and the mRNA level in primary cultured rat adipocytes treated with triacsin C, which is a potent inhibitor of acyl-coenzyme A (CoA) synthetase, palmitate, and 2-bromopalmitate. Triacsin C (0 to 5 x 10(-5) mol/L) decreased leptin concentrations in the culture medium in a dose-dependent manner. Leptin mRNA levels were decreased to 10% of the control in the presence of triacsin C. The concentration of triacsin C needed to suppress leptin production was similar to the Ki value (approximately 10(-5) mol/L) for inhibition of acyl-CoA synthetase. Both palmitate and 2-bromopalmitate decreased leptin concentra-tions but did not affect the triacsin C-induced decrease in leptin additively. In conclusion, both protein and mRNA levels of leptin were decreased by triacsin C and FFA in primary cultured rat adipocytes. Our findings suggest that FFA is involved in the regulation of leptin production in adipocytes.

Adipocytes↗

PubMed2000

Hepatitis C virus clearance is prominent in women in an endemic area.

BACKGROUND: The clinical and virological backgrounds of cases with previous hepatitis C virus (HCV) infection (positive for HCV antibody (anti-HCV) and HCV-RNA negative) in an HCV endemic area were examined to identify factors related to the clearance of HCV. METHODS: The study population comprised 3117 inhabitants, 1037 male and 2080 female, from an HCV endemic area. Hepatitis C virus antibody was detected by a passive haemagglutination test. The HCV-RNA and the HCV genotype were detected by using the polymerase chain reaction method. The HCV serotype was determined by enzyme immunoassay by using the peptides of the core region. RESULTS: Twenty-two per cent of the inhabitants were positive for anti-HCV, with males and the elderly having a significantly higher antibody titre (P < 0.01) than youths and females. Hepatitis C virus-RNA was detected in 78% of the HCV antibody-positive cases. The rate of HCV-RNA positivity was significantly higher in males than in females (P < 0.01). No relationship was found between HCV-RNA positivity and age. The HCV genotype 1b was the predominant genotype among the HCV-RNA-positive cases. Mixed genotypes (1b + 2a) were observed in 12% of cases, primarily in elderly males and females. In cases with previous HCV infection, serotype 1 was the most common serotype, and there appeared to be no relationship between the distribution of HCV serotypes and age and gender. There was a female predominance with regard to previous HCV infection, but not to being HCV carriers (P < 0.01). CONCLUSIONS: Gender, not HCV genotype, is the primary factor influencing HCV clearance.

Adult↗

PubMed2000

Non-specific interstitial pneumonia: findings on sequential CT scans of nine patients.

BACKGROUND: The purpose of this study was to describe findings on sequential high resolution computed tomographic (CT) scans of nine patients with non-specific interstitial pneumonia. METHODS: Thin section CT scans of nine patients with pathologically proven non-specific interstitial pneumonia were evaluated retrospectively. All patients underwent sequential CT scanning (mean follow up 3.1 years (range 1-8)). RESULTS: The predominant finding on the initial CT scans in seven patients was patchy areas of ground glass opacity in both the central and peripheral lung, with (n = 5) or without (n = 2) irregular areas of consolidation. In another two patients areas of consolidation in both the central and peripheral lung were seen as the predominant abnormality. The initial parenchymal abnormalities had resolved completely in four patients with predominant ground glass opacity without bronchiolectasis. Some of the bronchiectasis and bronchiolectasis resolved. In two patients bronchiectasis and bronchiolectasis occurred at one year and two years of follow up, respectively. In two patients with predominant consolidation the consolidation decreased but persisted, and in one patient the consolidation evolved into honeycombing. In the other patient bronchiectasis progressed over the course of seven years, forming varicoid bronchiectasis. CONCLUSION: Patients with non-specific interstitial pneumonia may recover completely after treatment with corticosteroids, but as many as half of these patients will have persistent pulmonary abnormalities on CT scans including bronchiectasis and honeycomb lung.

Adult↗

PubMed2000

Pathophysiological role of leptin in obesity-related hypertension.

To explore the pathophysiological role of leptin in obesity-related hypertension, we examined cardiovascular phenotypes of transgenic skinny mice whose elevated plasma leptin concentrations are comparable to those seen in obese subjects. We also studied genetically obese KKA(y) mice with hyperleptinemia, in which hypothalamic melanocortin system is antagonized by ectopic expression of the agouti protein. Systolic blood pressure (BP) and urinary catecholamine excretion are elevated in transgenic skinny mice relative to nontransgenic littermates. The BP elevation in transgenic skinny mice is abolished by alpha(1)-adrenergic, beta-adrenergic, or ganglionic blockers at doses that do not affect BP in nontransgenic littermates. Central administration of an alpha-melanocyte-stimulating hormone antagonist causes a marked increase in cumulative food intake but no significant changes in BP. The obese KKA(y) mice develop BP elevation with increased urinary catecholamine excretion relative to control KK mice. After a 2-week caloric restriction, BP elevation is reversed in nontransgenic littermates with the A(y) allele, in parallel with a reduction in plasma leptin concentrations, but is sustained in transgenic mice overexpressing leptin with the A(y) allele, which remain hyperleptinemic. This study demonstrates BP elevation in transgenic skinny mice and obese KKA(y) mice that are both hyperleptinemic, thereby suggesting the pathophysiological role of leptin in some forms of obesity-related hypertension.

Adrenergic alpha-Antagonists↗

PubMed2000

Constitutively active mitogen-activated protein kinase kinase increases GLUT1 expression and recruits both GLUT1 and GLUT4 at the cell surface in 3T3-L1 adipocytes.

To address a role of mitogen-activated protein kinase (MAPK) in the regulation of glucose transport, we made a constitutively active mutant of MAPK kinase (MAPKK) and introduced it into 3T3-L1 preadipocytes by using a retrovirus-mediated transfection procedure. The deletion of 20 amino acids (those between and including 32 and 51) in the amino terminal region of Xenopus MAPKK and the replacement of serine residues on the 218 and 222 positions by glutamic acid (dSESE-MAPKK) let Xenopus MAPKK constitutively active. The isolated cell clones differently expressing dSESE-MAPKK (clone 219 higher expression, clone 233 lower expression) efficiently differentiated to adipocytes by a standard differentiation cocktail. Accordingly, the increased expression of dSESE-MAPKK protein during differentiation resulted in the increased basal MAPK activity in clone 219 adipocytes and, to a lesser extent, in clone 233 adipocytes. In contrast to clone 233 and parental adipocytes, basal 2-deoxyglucose uptake was enhanced fourfold in clone 219 adipocytes, in accordance with increased expression of GLUT1 mRNA and protein. Whereas GLUT4 mRNA was similarly expressed in all of the adipocytes, GLUT4 protein appeared to decrease in clone 219 adipocytes. More importantly, subcellular fractionation studies showed that the localization of both GLUT1 and GLUT4 in the plasma membranes (PMs) was markedly increased in the basal state in clone 219 adipocytes compared with that in clone 233 and parental adipocytes, in which both glucose transporters were preferentially located in intracellular compartments. Consequently, insulin-induced translocation of GLUT1 was abolished in clone 219 adipocytes, although the remaining intracellular GLUT4 was still responsive to insulin stimulation, which led to the movement to the PM. As combined effects on the situation of GLUT1 and GLUT4, the foldness of insulin stimulation of glucose transport based on the basal activity was reduced in cells expressing constitutively active MAPKK. These results imply that chronic activation of MAPK could be one of the mechanisms for insulin resistance.

3T3 Cells↗

PubMed1999

Development of an in vitro reconstitution assay for glucose transporter 4 translocation.

In an attempt to define the mechanism of insulin-regulated glucose transporter 4 (Glut4) translocation, we have developed an in vitro reconstitution assay. Donor membranes from 3T3-L1 adipocytes transfected with mycGlut4 were incubated with plasma membrane (PM) from nontransfected 3T3-L1 cells, and the association was assessed by using two types of centrifugation assays. Association of mycGlut4 vesicles derived from donor membranes with the PM was concentration-, temperature-, time-, and Ca(2+)-dependent but ATP-independent. Addition of a syntaxin 4 fusion protein produced a biphasic response, increasing association at low concentration and inhibiting association at higher concentrations. PM from insulin-stimulated cells showed an enhanced association as compared with those from untreated cells. Use of donor membranes from insulin-stimulated cells further enhanced the association and also enhanced association to the PM from isolated rat adipocytes. Addition of cytosol, GTP, or guanosine 5'-[gamma-thio]triphosphate decreased the association. In summary, insulin-induced Glut4 translocation can be reconstituted in vitro to a limited extent by using isolated membranes. This association appears to involve protein-protein interactions among the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex proteins. Finally, the ability of insulin to enhance association depends on insulin-induced changes in the PM and, to a lesser extent, in the donor membranes.

3T3 Cells↗