Inhibitory effect of ceramide on insulin-induced protein kinase Czeta translocation in rat adipocytes

Ceramide has been confirmed to be a signal mediator of apoptosis that is induced by tumor necrosis factor-alpha (TNF-alpha). It has also been reported that ceramide may induce insulin resistance as well as TNF-alpha. We investigated the effect of ceramide on insulin signaling pathways, such as insulin receptor (IR) beta-subunit, insulin receptor substrate 1 (IRS-1), phosphatidylinositol 3-kinase (PI3K), and protein kinase Czeta (PKCzeta) in rat adipocytes. We examined insulin-stimulated [(3)H]2-deoxyglucose (2-DOG) uptake in rat adipocytes pretreated with N-hexanoylsphingosine (C(6)-ceramide, 10 to 30 micromol/L). Insulin-induced 2-DOG uptake was significantly reduced by C(6)-ceramide pretreatment. We also examined the effect of various concentrations of C(6)-ceramide pretreatment on insulin-induced autophosphorylation of the IR beta-subunit, tyrosine phosphorylation of IRS-1, enzyme activity of PI3K, and membrane-associated PKCzeta immunoreactivity. Pretreatment with C(6)-ceramide significantly reduced autophosphorylation of the IR beta-subunit, tyrosine phosphorylation of IRS-1, and enzyme activity of PI3K. Moreover, membrane-associated PKCzeta immunoreactivity and immunoprecipitable PKCzeta enzyme activity, downstream of PI3K, were significantly suppressed by C(6)-ceramide pretreatment. These results suggest that ceramide may induce insulin resistance via the suppression of IRS-1-PI3K signaling, and subsequent activation of PKCzeta.     

Disseminated gonococcal infection in a Japanese man with complement 7 deficiency with compound heterozygous variants: A case report

Rationale:Complement deficiency are known to be predisposed to disseminated gonococcal infection (DGI). We herein present a case of DGI involving a Japanese man who latently had a complement 7 deficiency with compound heterozygous variants.Patient concerns:A previously healthy 51-year-old Japanese man complained of sudden-onset high fever. Physical examination revealed various skin lesions including red papules on his trunk and extremities, an impetigo-like pustule on left forearm, and tendinitis of his right forefinger.Diagnosis:Blood culture testing detected gram-negative cocci, which was confirmed to be Neisseria gonorrhoeae based on mass spectrometry and a pathogen-specific PCR test.Interventions:Screening tests for underlying immunocompromised factors uncovered that complement activities (CH50) was undetectable. With a suspicion of a congenital complement deficiency, genetic analysis revealed rare single nucleotide variants in complement 7 (C7), including c.281-1G>T and a novel variant c.1454C>T (p.A485V). CH50 was normally recovered by adding purified human C7 to the patient''s serum, supporting that the patient has C7 deficiency with compound heterozygous variants.Outcomes:Under a diagnosis of DGI, the patient underwent an antibiotic treatment with cefotaxime for a week and was discharged without any sequela.Lessons:DGI is a rare sexually-transmitted infection that potentially induces systemic complications. Complement immunity usually defeats N. gonorrhoeae and prevents the organism from causing DGI. This case highlighted the importance of suspecting a complement deficiency when a person develops DGI.     

Fibrosis of liver, pancreas and intestine: common mechanisms and clear targets?

Chronic diseases of the liver, pancreas, intestine, kidneys, skin and lungs are usually accompanied by scarring. Loss of organ function is often progressive despite the use of immunosuppressive, antiviral or antiinflammatory agents. Therefore, well tolerated antifibrotic therapies are urgently needed. The targets for such therapies are activated mesenchymal cells that synthesize an excess of matrix proteins and resemble the myofibroblasts of healing wounds. These cells derive from normally quiescent fibroblasts or smooth muscle cells and from stellate cells of liver and pancreas. Their activation is triggered and maintained by mechanical stress and several fibrogenic modulators and cytokines. Some agents inhibit myofibroblast proliferation and collagen synthesis in vitro, but only few of them are effective in vivo. Potential antifibrotic drugs have been tested mainly in models of liver fibrosis. In the suitable rat model of biliary fibrosis, an antifibrotic effect was demonstrated for silymarin, a defined mixture of flavonoids, and to a lesser degree for pentoxifylline. A spin-off of the large multicenter trials for hepatitis C is the finding that interferon-alpha given for 6-12 months may halt or reverse fibrosis, even in virological non-responders. This has to be proven in prospective randomized trials. Specific inhibitors of the endothelin-A-receptor which are orally available can suppress liver collagen accumulation by 40-60%. Other strategies aim at inhibition of the profibrogenic cytokines TGF-beta or connective tissue growth factor. Effective drug targeting to the fibrogenic liver cells is now possible by use of cyclic peptides that bind to receptors which are specifically upregulated on activated stellate cells. Blockade of such activation receptors can induce stress-relaxation which reverts the fibrogenic cells to a fibrolytic, collagen degrading phenotype. Fibrosis has been discovered as a novel target for the pharmaceutical industry. This implies the use of combinatorial chemistry and an automatized screening machinery, greatly speeding up the design and selection of specific antifibrotic agents. Combined with the rapidly evolving validation of serological markers of fibrogenesis and fibrolysis unforeseen progress in the treatment of organ fibrosis can be expected.     

Scirrhous carcinoma of the stomach: A clinical and pathological study of 106 surgical cases

Clinical and pathological characteristics of scirrhous carcinoma of the stomach were studied in 106 cases treated by gastrectomy between 1973 and 1983. The male to female ratio was 0.58. The percentage of scirrhous carcinomas to all gastric carcinomas resected in the same period was three times higher in females than males. The age distribution of the patients suggested that there were two peaks in the forties and sixties in the male, and in the thirties and fifties in the female. The incidence of scirrhous carcinoma in all types of gastric carcinoma was significantly higher in the twenties, thirties and forties compared to the lowest incidence in the seventies. In the female group the primary lesion had a tendency to be adjacent to the fundic gland area and to avoid intestinal metaplasia. In the male the opposite was recognized. Cancer nests with single cells or only several cells were common in this type of carcinoma. These findings suggest that there might be two biologically different scirrhous carcinomas both in the male and the female, the appearance of single carcinoma cells might be favored by female sex hormones and young ages, and not only the original gastric mucosa but also mucosa with intestinal metaplasia could be precursors of single carcinoma cells.     

PDE5 inhibitor sildenafil citrate augments endothelium-dependent vasodilation in smokers

Smoking is associated with endothelial dysfunction. The purpose of this study was to determine the effect of sildenafil, an inhibitor of phosphodiesterase type 5 (PDE5), on endothelial function in smokers. We evaluated the forearm blood flow (FBF) responses to acetylcholine (ACh), an endothelium-dependent vasodilator, and to sodium nitroprusside (SNP), an endothelium-independent vasodilator, before and after oral sildenafil administration (100 mg) with a strain-gauge plethysmograph in 10 young healthy male smokers and 10 young healthy male nonsmokers. FBF response to ACh was lower in smokers than in nonsmokers. The vasodilatory effects of SNP were similar in both groups. Sildenafil increased the FBF response to ACh from 9.3+/-2.0 to 12.5+/-3.5 mL/min per 100 mL tissue in smokers and from 12.6+/-5.6 to 19.6+/-8.4 mL/min per 100 mL tissue in nonsmokers, and it increased the response to SNP from 13.3+/-3.9 to 15.1+/-4.3 mL/min per 100 mL tissue in smokers and from 14.8+/-5.2 to 18.4+/-6.0 mL/min/100 mL tissue in nonsmokers (P<0.05 for all). The ratio of maximal ACh-stimulated FBF expressed as a ratio of maximal SNP-stimulated FBF significantly increased after administration of sildenafil in both groups. Infusion of NG-monomethyl-L-arginine, a nitric oxide synthase inhibitor, abolished sildenafil-induced augmentation of the FBF response to ACh in both groups. The findings suggest that endothelial function is impaired in smokers compared with that in nonsmokers, that inhibition of PDE5 by sildenafil significantly increases nitric oxide-mediated vasodilation, and that the activities of PDE5 in smokers and nonsmokers may be similar.     

Diagnostic and predictive performance and standardized threshold of traditional biomarkers for drug‐induced liver injury in rats

Traditional biomarkers such as alanine and aspartate aminotransferase (ALT, AST) and total bilirubin (TBIL) have been widely used for detecting drug‐induced liver injury (DILI). Although the Food and Drug Administration (FDA) proposed standardized thresholds for human as Hy's law, those for animals have not been determined, and predictability of these biomarkers for future onset of hepatic lesions remains unclear. In this study, we investigated these diagnostic and predictive performance of 10 traditional biomarkers for liver injury by receiver‐operating characteristic (ROC) curve, using a free‐access database where 142 hepatotoxic or non‐hepatotoxic compounds were administrated to male rats (n = 5253). Standardization of each biomarker value was achieved by calculating the ratio to control mean value, and the thresholds were determined under the condition of permitting 5% false positive. Of these 10 biomarkers, AST showed the best diagnostic performance. Furthermore, ALT and TBIL also showed high performance under the situation of hepatocellular necrosis and bile duct injury, respectively. Additionally, the availability of the diagnostic thresholds in difference testing facility was confirmed by the application of these thresholds to in‐house prepared dataset. Meanwhile, incorrect diagnosis by the thresholds was also observed. Regarding prediction, all 10 biomarkers showed insufficient performance for future onset of hepatic lesions. In conclusion, the standardized diagnostic thresholds enable consistent evaluation of traditional biomarkers among different facilities, whereas it was suggested that novel biomarker is required for more accurate diagnosis and prediction of DILI. Copyright © 2014 John Wiley & Sons, Ltd.     

Pulmonary thromboembolism. Evaluating the indication and effect of a vena caval filter with indium-111-platelet scintigraphy.

A 63-year-old woman complained of chest pain and was referred to hospital where she was found to have left pleural effusion and swelling, local heat and edema of the right lower leg. Initial pulmonary perfusion scintigraphy demonstrated multiple defects and pulmonary thromboembolism (PTE) was confirmed during the anticoagulant and thrombolytic therapy against thrombophlebitis. A Greenfield filter was inserted in the inferior vena cava to prevent recurrence of PTE from the thrombosis that was resistant to therapy. In-111-labeled platelet scintigraphy (platelet scintigraphy) showed abnormal uptake of platelets in the chest, femoral veins and abdomen, which suggested active thrombus formation in those regions, including the filter, and a risk of recurrent PTE. Therefore, the thrombolytic therapy was terminated and the anticoagulant therapy intensified. A computed tomography (CT) scan revealed thrombus at the filter, which was markedly decreased 1 month later on platelet scintigraphy. Pulmonary ventilation and perfusion scintigraphy revealed remarkable improvement of the PTE. In this case, platelet scintigraphy complemented CT in demonstrating the activity and localization of the thrombus and can be used to evaluate the risk of recurrence during thrombolytic therapy after insertion of a filter.     

Telomere length in human liver diseases

Abstract: To determine the role of telomere-mediated gene stability in hepatocarcinogenesis, we examined the telomere length of human liver with or without chronic liver diseases and hepatocellular carcinomas (HCC). The mean telomere restriction fragment (TRF) length of normal liver (n=13), chronic hepatitis (n=11), liver cirrhosis (n=24) and HCC (n=24) was 7.8±0.2, 7.1±0.3, 6.4±0.2 and 5.2±0.2 kb, respectively (mean±standard error). TRF length decreased with a progression of chronic liver diseases and that in HCC was significantly shorter than that in other chronic liver diseases (p<0.05). The ratios of TRF length of HCC to that of corresponding surrounding liver of well differentiated (n=7), moderately differentiated (n=10) and poorly differentiated (n=4) HCCs were 0.83±0.06, 0.75±0.05 and 0.98±0.09, respectively. The ratio of poorly differentiated HCC was significantly higher than that of moderately differentiated HCC (p<0.05). A comparison between the size and telomere length ratio of moderately differentiated HCCs revealed a decrease of the ratio with size until it reached 50 mm in diameter. In contrast, the ratio increased as the size enlarged over 50 mm. These findings suggest that the gene stability of the liver cells mediated by the telomere is reduced as chronic liver disease progresses and that telomerase is activated in poorly differentiated HCC and moderately differentiated HCC over 50 mm in diameter.