CDK4 is an essential insulin effector in adipocytes

Insulin resistance is a fundamental pathogenic factor that characterizes various metabolic disorders, including obesity and type 2 diabetes. Adipose tissue contributes to the development of obesity-related insulin resistance through increased release of fatty acids, altered adipokine secretion, and/or macrophage infiltration and cytokine release. Here, we aimed to analyze the participation of the cyclin-dependent kinase 4 (CDK4) in adipose tissue biology. We determined that white adipose tissue (WAT) from CDK4-deficient mice exhibits impaired lipogenesis and increased lipolysis. Conversely, lipolysis was decreased and lipogenesis was increased in mice expressing a mutant hyperactive form of CDK4 (CDK4(R24C)). A global kinome analysis of CDK4-deficient mice following insulin stimulation revealed that insulin signaling is impaired in these animals. We determined that insulin activates the CCND3-CDK4 complex, which in turn phosphorylates insulin receptor substrate 2 (IRS2) at serine 388, thereby creating a positive feedback loop that maintains adipocyte insulin signaling. Furthermore, we found that CCND3 expression and IRS2 serine 388 phosphorylation are increased in human obese subjects. Together, our results demonstrate that CDK4 is a major regulator of insulin signaling in WAT.

Effect upon mortality of the extension to holidays and weekends of the "ICU without walls" project. A before-after study

OBJECTIVE

To determine whether extension to holidays and weekends of the protocol for the early proactive detection of severity in hospital ("ICU without walls" project) results in decreased mortality among patients admitted to the ICU during those days.

DESIGN

A quasi-experimental before-after study was carried out.

SETTING

A level 2 hospital with 210 beds and a polyvalent ICU with 8 beds.

PATIENTS OR PARTICIPANTS

The control group involved no "ICU without walls" activity on holidays or weekends and included those patients admitted to the ICU on those days between 1 January 2010 and 30 April 2013. The intervention group in turn extended the "ICU without walls" activity to holidays and weekends, and included those patients admitted on those days between 1 May 2013 and 31 October 2014. Patients arriving from the operating room after scheduled surgery were excluded.

VARIABLES OF INTEREST

An analysis was made of the demographic variables (age, gender), origin (emergency room, hospital ward, operating room), type of patient (medical, surgical), reason for admission, comorbidities and SAPS 3 score as a measure of severity upon admission, stay in the ICU and in hospital, and mortality in the ICU and in hospital.

RESULTS

A total of 389 and 161 patients were included in the control group and intervention group, respectively. There were no differences between the 2 groups except as regards cardiovascular comorbidity (49% in the control group versus 33% in the intervention group; P<.001), severity upon admission (median SAPS 3 score 52 [percentiles 25-75: 42-63) in the control group versus 48 [percentiles 25-75: 40-56] in the intervention group; P=.008) and mortality in the ICU (11% in the control group [95% CI 8-14] versus 3% [95% CI 1-7] in the intervention group; P=.003). In the multivariate analysis, the only 2 factors associated to mortality in the ICU were the SAPS 3 score (OR 1.08; 95% CI 1.06-1.11) and inclusion in the intervention group (OR 0.33; 95% CI 0.12-0.89).

CONCLUSIONS

Extension of the "ICU without walls" activity to holidays and weekends results in a decrease in mortality in the ICU.

Effect of the timing of admission upon patient prognosis in the Intensive Care Unit: On-hours versus off-hours

OBJECTIVE

To assess the repercussion of the timing of admission to the ICU upon patient prognosis.

DESIGN

A prospective, observational, non-interventional cohort study was carried out.

SCOPE

A second level hospital with 210 operational beds and a general ICU with 8 operational beds.

PATIENTS OR PARTICIPANTS

The study comprised all patients admitted to the ICU during 3 years (January 2010 to December 2012), excluding those subjects admitted from the operating room after scheduled surgery. The patients were divided into 2 groups according to the timing of admission (on-hours or off-hours).

INTERVENTIONS

Non-interventional study.

VARIABLES OF INTEREST

An analysis was made of demographic variables (age, sex), origin (emergency room, hospital ward, operating room), comorbidities and SAPS 3 as severity score upon admission, length of stay in the ICU and hospital ward, and ICU and hospital mortality.

RESULTS

A total of 504 patients were included in the on-hours group, versus 602 in the off-hours group. Multivariate analysis showed the factors independently associated to hospital mortality to be SAPS 3 (OR 1.10; 95% CI 1.08-1.12), and off-hours admission (OR 2.00; 95% CI 1.20-3.33). In a subgroup analysis of the off-hours group, the admission of patients on weekends or non-working days compared to daily night shifts was found to be independently associated to hospital mortality (OR 2.30; 95% CI 1.23-4.30).

CONCLUSIONS

Admission to the ICU in off-hours is independently associated to patient mortality, which is also higher in patients admitted on weekends and non-working days compared to the daily night shifts.

Intensive care unit without walls: seeking patient safety by improving the efficiency of the system

The term "ICU without walls" refers to innovative management in Intensive Care, based on two key elements: (1) collaboration of all medical and nursing staff involved in patient care during hospitalization and (2) technological support for severity early detection protocols by identifying patients at risk of deterioration throughout the hospital, based on the assessment of vital signs and/or laboratory test values, with the clear aim of improving critical patient safety in the hospitalization process. At present, it can be affirmed that there is important work to be done in the detection of severity and early intervention in patients at risk of organ dysfunction. Such work must be adapted to the circumstances of each center and should include training in the detection of severity, multidisciplinary work in the complete patient clinical process, and the use of technological systems allowing intervention on the basis of monitored laboratory and physiological parameters, with effective and efficient use of the information generated. Not only must information be generated, but also efficient management of such information must also be achieved. It is necessary to improve our activity through innovation in management procedures that facilitate the work of the intensivist, in collaboration with other specialists, throughout the hospital environment. Innovation is furthermore required in the efficient management of the information generated in hospitals, through intelligent and directed usage of the new available technology.

[Selective digestive decontamination. Why don't we apply the evidence in the clinical practice?]

Selective digestive decontamination (SDD) is a prophylactic strategy whose objective is to reduce the incidence of infections, mainly mechanical ventilation associated pneumonia in patients who require intensive cares, preventing or eradicating the oropharyngeal and gastrointestinal carrier state of potentially pathogenic microorganisms. Fifty-four randomized clinical trials (RCTs) and 9 meta-analysis have evaluated SDD. Thirty eight RCTs show a significant reduction of the infections and 4 of mortality. All the meta-analyses show a significant reduction of the infections and 5 out of the 9 meta-analyses report a significant reduction in mortality. Thus, 5 patients from the ICU with SDD must be treated to prevent pneumonia and 12 patients from the ICU should be treated to prevent one death. The data that show benefit of the SDD on mortality have an evidence grade 1 or recommendation grade A (supported by at least two level 1 investigations). The aim of this review is to explain the pathogeny of infections in critical patients, describe selective digestive decontamination, analyze the evidence available on it efficacy and the potential adverse effects and discuss the reasons published by the experts who advise against the use of SDD, even though it is recognized as the best intervention evaluated in intensive cares to reduce morbidity and mortality of the infections.

Temporal bone rhabdomyosarcoma in children

OBJECTIVE

Rhabdomyosarcoma is the most frequent soft tissue sarcoma in the pediatric age group. The authors present their series of rhabdomyosarcoma of the temporal bone in children at Saint Justine Hospital. The twofold objective of this study is to illustrate the clinical presentation, management, and prognosis of this malignant striated muscle tumor, and to compare these results with previously reported series.

METHODS

A retrospective study was conducted of patients diagnosed and treated for rhabdomyosarcoma of the head and neck at Saint Justine Hospital, a tertiary pediatric center, between 1970 and 2005. Only cases of temporal bone rhabdomyosarcoma were included in the study. A thorough review of medical and surgical charts was performed to obtain demographic, clinical, paraclinical, and therapeutic data, which were subsequently analyzed and compared to published results. A MEDLINE search yielded 34 studies dealing with temporal bone rhabdomyosarcoma since the year 1966.

RESULTS

Thirty-nine patients with rhabdomyosarcoma of the head and neck region were identified, among which only six children had temporal bone rhabdomyosarcoma. The mean age at the time of diagnosis was 4.15 years. Chronic otitis media was the most common clinical presentation. Five children had the embryonal subtype and one had the botryoid subtype on histology. All patients except two received combined chemotherapy and radiotherapy as treatment. Five-year survival rate was 66%. Our results match those reported in the literature 41-81%.

CONCLUSION

Rhabdomyosarcoma of the temporal bone is an aggressive tumor that clinically simulates chronic otitis media. A high index of suspicion should be raised in the context of otitis media that is unresponsive to ordinary medical treatment. A biopsy is hence recommended in the presence of polyps in the external auditory canal that are resistant to medical treatment. Early diagnosis and the adoption of multimodal therapy offer the best outcome.

Oral insulin-mimetic compounds that act independently of insulin

The hallmarks of insulin action are the stimulation and suppression of anabolic and catabolic responses, respectively. These responses are orchestrated by the insulin pathway and are initiated by the binding of insulin to the insulin receptor, which leads to activation of the receptor's intrinsic tyrosine kinase. Severe defects in the insulin pathway, such as in types A and B and advanced type 1 and 2 diabetes lead to severe insulin resistance, resulting in a partial or complete absence of response to exogenous insulin and other known classes of antidiabetes therapies. We have characterized a novel class of arylalkylamine vanadium salts that exert potent insulin-mimetic effects downstream of the insulin receptor in adipocytes. These compounds trigger insulin signaling, which is characterized by rapid activation of insulin receptor substrate-1, Akt, and glycogen synthase kinase-3 independent of insulin receptor phosphorylation. Administration of these compounds to animal models of diabetes lowered glycemia and normalized the plasma lipid profile. Arylalkylamine vanadium compounds also showed antidiabetic effects in severely diabetic rats with undetectable circulating insulin. These results demonstrate the feasibility of insulin-like regulation in the complete absence of insulin and downstream of the insulin receptor. This represents a novel therapeutic approach for diabetic patients with severe insulin resistance.

Peroxisome proliferator-activated receptor gamma regulates E-cadherin expression and inhibits growth and invasion of prostate cancer

Peroxisome proliferator-activated receptor gamma (PPARgamma) might not be permissive to ligand activation in prostate cancer cells. Association of PPARgamma with repressing factors or posttranslational modifications in PPARgamma protein could explain the lack of effect of PPARgamma ligands in a recent randomized clinical trial. Using cells and prostate cancer xenograft mouse models, we demonstrate in this study that a combination treatment using the PPARgamma agonist pioglitazone and the histone deacetylase inhibitor valproic acid is more efficient at inhibiting prostate tumor growth than each individual therapy. We show that the combination treatment impairs the bone-invasive potential of prostate cancer cells in mice. In addition, we demonstrate that expression of E-cadherin, a protein involved in the control of cell migration and invasion, is highly up-regulated in the presence of valproic acid and pioglitazone. We show that E-cadherin expression responds only to the combination treatment and not to single PPARgamma agonists, defining a new class of PPARgamma target genes. These results open up new therapeutic perspectives in the treatment of prostate cancer.

Cyclin D3 promotes adipogenesis through activation of peroxisome proliferator-activated receptor gamma

In addition to their role in cell cycle progression, new data reveal an emerging role of D-type cyclins in transcriptional regulation and cellular differentiation processes. Using 3T3-L1 cell lines to study adipogenesis, we observed an up-regulation of cyclin D3 expression throughout the differentiation process. Surprisingly, cyclin D3 was only minimally expressed during the initial stages of adipogenesis, when mitotic division is prevalent. This seemingly paradoxical expression led us to investigate a potential cell cycle-independent role for cyclin D3 during adipogenesis. We show here a direct interaction between cyclin D3 and the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma). Our experiments reveal cyclin D3 acts as a ligand-dependent PPARgamma coactivator, which, together with its cyclin-dependent kinase partner, phosphorylates the A-B domain of the nuclear receptor. Overexpression and knockdown studies with cyclin D3 had marked effects on PPARgamma activity and subsequently on adipogenesis. Chromatin immunoprecipitation assays confirm the participation of cyclin D3 in the regulation of PPARgamma target genes. We show that cyclin D3 mutant mice are protected from diet-induced obesity, display smaller adipocytes, have reduced adipogenic gene expression, and are insulin sensitive. Our results indicate that cyclin D3 is an important factor governing adipogenesis and obesity.

The release of soluble VAP-1/SSAO by 3T3-L1 adipocytes is stimulated by isoproterenol and low concentrations of TNFalpha

Plasma level of the protein VAP-1/SSAO (Vascular Adhesion Protein-1/Semicarbazide-Sensitive Amine Oxidase) is increased in diabetes and/or obesity and may be related to vascular complications associated to these pathologies. The aim of this work was to complete a preceding study where we described the role played by some hormones or metabolites, implicated in diabetes and/or obesity, in the regulation of the release of VAP-1/SSAO by 3T3-L1 adipocytes. Here we focused on the previously observed effect produced by TNFalpha in the release of VAP-1/SSAO and studied the effect of a beta-adrenergic compound, isoproterenol. Both compounds stimulated the release of VAP-1/SSAO to the culture medium but had a different effect on the VAP-1/SSAO membrane form. While TNFalpha produced a decrease on VAP-1/SSAO membrane form content, isoproterenol did not modify it. We thus observed two different ways of regulation of the release of VAP-1/SSAO by 3T3-L1 adipocytes by metabolites implicated in diabetes and adipose tissue physiopathology. Our work permits a better understanding of this increased plasma VAP-1/SSAO levels observed in diabetes.

Cdk4 promotes adipogenesis through PPARgamma activation

Cell cycle regulators such as E2F1 and retinoblastoma (RB) play crucial roles in the control of adipogenesis, mostly by controlling the transition between preadipocyte proliferation and adipocyte differentiation. The serine-threonine kinase cyclin-dependent kinase 4 (cdk4) works in a complex with D-type cyclins to phosphorylate RB, mediating the entry of cells into the cell cycle in response to external stimuli. Because cdk4 is an upstream regulator of the E2F-RB pathway, we tested whether cdk4 was a target for new factors that regulate adipogenesis. Here we find that cdk4 inhibition impairs adipocyte differentiation and function. Disruption of cdk4 or activating mutations in cdk4 in primary mouse embryonic fibroblasts results in reduced and increased adipogenic potential, respectively, of these cells. We show that the effects of cdk4 are not limited to the control of differentiation; cdk4 also participates in adipocyte function through activation of PPARgamma.

[Influence of pyridoxal phosphate in measuring aminotransferases activities in patients with viral hepatitis]

Effect of a pyridoxal phosphate (PP) supplementation of reagents used for ALT and AST measurement was studied in serum of 20 patients suffering from viral hepatitis. Measurements of enzyme activities were carried out at 37 degrees C, using an automate (AU 600, Olympus). Significant differences (p < 0.0001) were observed both for ALT and AST, meanwhile they were more marked for ALT than for AST. This difference was associated with a strong interindividual variability regarding PP activation effect on ALT. In conclusion, aminotransferase measurements should be carried out with a reagent supplemented with PP, when the enzyme activity is used to evaluate a cytolysis. The same recommendation applies when ALT results are integrated into various combinations developed for the evaluation of liver status.

Exploring the binding mode of semicarbazide-sensitive amine oxidase/VAP-1: identification of novel substrates with insulin-like activity

We previously reported that substrates of semicarbazide-sensitive amine oxidase in combination with low concentrations of vanadate exert potent insulin-like effects. Here we performed homology modeling of the catalytic domain of mouse SSAO/VAP-1 and searched through chemical databases to identify novel SSAO substrates. The modeling of the catalytic domain revealed that aromatic residues Tyr384, Phe389, and Tyr394 define a pocket of stable size that may participate in the binding of apolar substrates. We identified a number of amines as substrates of human, rat, and mouse SSAO. The compounds PD0119035, 2,3-dimethoxy-benzylamine, and C-naphthalen-1-yl-methylamine showed high affinity as substrates of rat SSAO. C-Naphthalen-1-yl-methylamine was the only substrate that showed high affinity for human SSAO. C-Naphthalen-1-yl-methylamine and 4-aminomethyl-benzenesulfonamide showed the highest capacity to stimulate glucose transport in isolated rat adipocytes. The impact of these findings on the development of new treatments for diabetes is discussed.

Stimulation of glucose transport by semicarbazide-sensitive amine oxidase activity in adipocytes from diabetic rats

Semicarbazide-sensitive amine oxidase (SSAO) is highly expressed in adipose cells, and substrates of SSAO such as benzylamine in combination with low concentrations of vanadate strongly stimulate glucose transport and GLUT4 recruitment in mouse 3T3-L1 adipocytes and in isolated rat adipocytes. Here we examined whether this combination of molecules also stimulates glucose transport in adipocytes from streptozotocin-induced diabetic rats and from Goto-Kakizaki diabetic rats. As previously reported, adipocytes obtained from streptozotocin-induced diabetic rats, showed a reduced stimulation of glucose transport in response to insulin. Under these conditions, the combination of benzylamine and vanadate caused a marked stimulation of glucose transport that was similar to the stimulation detected in control adipocytes. Adipocytes isolated from Goto-Kakizaki diabetic rats also showed a defective response to insulin; however, acute incubation in the presence of benzylamine and vanadate stimulated glucose transport in these cells to the same extent than in adipocytes from non-diabetic rats. These data indicate that adipocytes obtained from two different models of animal diabetes do not show resistance to the activation of glucose transport by SSAO activity, which is in contrast to the well reported resistance to insulin action. It seems to suggest that SSAO activity in combination with vanadate triggers a glucose transport-activating intracellular pathway that remains intact in the diabetic state. Further, our data support the view that the combination of benzylamine and vanadate could be an effective therapy in diabetes.

Adipocytes release a soluble form of VAP-1/SSAO by a metalloprotease-dependent process and in a regulated manner

AIMS/HYPOTHESIS

Vascular adhesion protein-1 (VAP-1), which is identical to semicarbazide-sensitive amine oxidase (SSAO), is a dual-function membrane protein with adhesion properties and amine oxidase activity. A soluble form of VAP-1 is found in serum, where concentrations are enhanced in diabetes and obesity. In vitro, soluble VAP-1 enhances lymphocyte adhesion to endothelial cells, thus possibly participating in the enhanced lymphocyte adhesion capacity that is implicated in the cardiovascular complications associated with diabetes or obesity. In both, the tissue origin of the soluble VAP-1/SSAO is unknown. We examined whether adipose tissue, which has abundant expression of VAP-1/SSAO, is a source of soluble VAP-1.

METHODS

We detected VAP-1/SSAO in plasma of diabetic animals, with or without VAP-1 immunoprecipitation, and in culture medium from 3T3-L1 adipocytes and human adipose tissue explants. VAP-1 protein glycosylation was measured.

RESULTS

Diabetic and obese animals have increased plasma SSAO activity associated with VAP-1 protein. We also found that 3T3-L1 adipocytes and human adipose tissue explants release a soluble form of VAP-1/SSAO, which derives from the membrane. The release of soluble VAP-1 was enhanced by exposure of murine and human adipocytes to TNF-alpha and blocked by batimastat, a metalloprotease inhibitor. Partial ablation of adipose tissue reduced plasma SSAO activity in normal and diabetic rats.

CONCLUSIONS/INTERPRETATION

Adipose cells are a source of soluble VAP-1/SSAO released by shedding of the membrane form. The release of SSAO is regulated by TNF-alpha and insulin. By releasing VAP-1/SSAO, adipose cells could contribute to the atherogenesis and vascular dysfunction associated with diabetes and obesity.

Reducing the number of T3 orders in the Paris hospital network: towards better appropriatness of thyroid function test prescription

In vitro thyroid function tests are among the most frequently prescribed laboratory procedures. Serum triiodothyronine (T3) tests are seldom necessary as a first-level measurement. Our objectives were to measure the proportion of T3 measurements relative to all in vitro thyroid function tests in a large hospital network and to investigate the contributions of various interventions to change prescribers'behavior. We performed two cross-sectional surveys in 1995 and 1998 in the 50 Paris University hospitals. Questionnaires were mailed to the heads of the 30 laboratories performing thyroid function tests. One-month orders of free and total thyroxine, free and total T3 and thyrotropin were recorded; changes in T3 measurement orders between the two periods were estimated and association with interventions were expressed as odds ratios and 95% confidence intervals. Twenty-five heads of laboratory responded to both surveys. In 1995, T3 measurements constituted 21% of in vitro thyroid function test ordering, which seems to us exceedingly high. The decrease in T3 measurement ordering observed in 1998 (15% of thyroid function test ordering) was independently associated with multiple behavioral changes: educational interventions, structured test form use and year of prescription.

Semicarbazide-sensitive amine oxidase activity exerts insulin-like effects on glucose metabolism and insulin-signaling pathways in adipose cells

Semicarbazide-sensitive amine oxidase (SSAO) is very abundant at the plasma membrane in adipocytes. The combination of SSAO substrates and low concentrations of vanadate markedly stimulates glucose transport and GLUT4 glucose transporter recruitment to the cell surface in rat adipocytes by a mechanism that requires SSAO activity and hydrogen peroxide formation. Substrates of SSAO such as benzylamine or tyramine in combination with vanadate potently stimulate tyrosine phosphorylation of both insulin-receptor substrates 1 (IRS-1) and 3 (IRS-3) and phosphatidylinositol 3-kinase (PI 3-kinase) activity in adipose cells, which occurs in the presence of a weak stimulation of insulin-receptor kinase. Moreover, the acute administration of benzylamine and vanadate in vivo enhances glucose tolerance in non-diabetic and streptozotocin-induced diabetic rats and reduces hyperglycemia after chronic treatment in streptozotocin-diabetic rats. Based on these observations, we propose that SSAO activity and vanadate potently mimic insulin effects in adipose cells and exert an anti-diabetic action in an animal model of type 1 diabetes mellitus.

Semicarbazide-sensitive amine oxidase/vascular adhesion protein-1 activity exerts an antidiabetic action in Goto-Kakizaki rats

In this study we have explored whether the bifunctional protein semicarbazide-sensitive amine oxidase (SSAO)/vascular adhesion protein-1 (VAP-1) represents a novel target for type 2 diabetes. To this end, Goto-Kakizaki (GK) diabetic rats were treated with the SSAO substrate benzylamine and with low ineffective doses of vanadate previously shown to have antidiabetic effects in streptozotocin-induced diabetic rats. The administration of benzylamine in combination with vanadate in type 2 diabetic rats acutely stimulated glucose tolerance, and the chronic treatment normalized hyperglycemia, stimulated glucose transport in adipocytes, and reversed muscle insulin resistance. Acute in vivo administration of benzylamine and vanadate stimulated skeletal muscle glucose transport, an effect that was also observed in incubated muscle preparations coincubated with adipose tissue explants or with human recombinant SSAO. Acute administration of benzylamine/vanadate also ameliorated insulin secretion in diabetic GK rats, and this effect was also observed in incubated pancreatic islets. In keeping with these observations, we also demonstrate that pancreatic islets express SSAO/VAP-1. As far as mechanisms of action, we have found that benzylamine/vanadate causes enhanced tyrosine phosphorylation of proteins and reduced protein tyrosine phosphatase activity in adipocytes. In addition, incubation of human recombinant SSAO, benzylamine, and vanadate generates peroxovanadium compounds in vitro. Based on these data, we propose that benzylamine/vanadate administration generates peroxovanadium locally in pancreatic islets, which stimulates insulin secretion and also produces peroxovanadium in adipose tissue, activating glucose metabolism in adipocytes and in neighboring muscle. This opens the possibility of using the SSAO/VAP-1 activity as a local generator of protein tyrosine phosphatase inhibitors in antidiabetic therapy.

Tumor necrosis factor soluble receptor p55 and lipid peroxidation in patients with acute alcoholic hepatitis

OBJECTIVES

In experimental models, liver injury induced by ethanol, cytotoxic activity of tumor necrosis factor (TNF) -alpha is principally mediated by TNF receptor p55 (TNFRp55). Among the various mechanisms underlying the toxic effects of TNF-alpha, overproduction of reactive oxygen species seems to play a key role in mediating TNF-alpha-induced cytotoxicity. The aim of this study was to evaluate, in patients with alcoholic liver disease, whether alcohol TNFRp55-mediated hepatotoxicity could account for lipid peroxidation expressed by significant increase in serum thiobarbituric reactive acid substances (TBARS) content, and could be amplified by decrease in blood total glutathione content and decrease in plasma antioxidant protective capacity.

METHODS

We studied 27 patients with histological alcoholic liver disease (five fibrosis, six acute alcoholic hepatitis (AAH) without cirrhosis, four cirrhosis without AAH, and 12 cirrhosis with AAH. TNFsRp55 and TNFsRp75 plasma levels were measured using ELISA assays. Plasma lipid peroxidation was evaluated by the content of TBARS. Total glutathione (tGSH) content in blood was determined by a kinetic assay. The sensitivity of erythrocytes to an oxidative stress and the plasma antioxidant protective capacity were simultaneously determined by a simple method.

RESULTS

In the 18 patients with mild or severe AAH, the plasma levels of TNFsRp55 were negatively correlated with tGSH and were positively correlated with TBARS, with total bilirubin and with discriminant function. tGSH was positively correlated with plasma selenium. The plasma levels of TNFsRp75 were positively correlated with TBARS and with total bilirubin. There was no significant correlation with the mean inhibitory 50% plasma volume or with the percentage of hemolyzed erythrocytes.

CONCLUSIONS

Our data support the notions that, in patients with AAH, TNFsRp55 probably mediates cytotoxicity of TNF-alpha, and that cytotoxic effect could be amplified by tGSH depletion in enhancing lipid peroxidation.

Combined treatment with benzylamine and low dosages of vanadate enhances glucose tolerance and reduces hyperglycemia in streptozotocin-induced diabetic rats

Semicarbazide-sensitive amine oxidase (SSAO) is highly expressed in adipose cells, and substrates of SSAO, such as benzylamine, in combination with low concentrations of vanadate strongly stimulate glucose transport and GLUT4 recruitment in 3T3-L1 and rat adipocytes. Here we examined whether acute and chronic administration of benzylamine and vanadate in vivo enhances glucose tolerance and reduces hyperglycemia in diabetic rats. Acute intravenous administration of these drugs enhanced glucose tolerance in nondiabetic rats and in streptozotocin (STZ)-induced diabetic rats. This occurred in the absence of changes in plasma insulin concentrations. However, the administration of benzylamine or vanadate alone did not improve glucose tolerance. The improvement caused by benzylamine plus vanadate was abolished when rats were pretreated with the SSAO-inhibitor semicarbazide. Chronic administration of benzylamine and vanadate exerted potent antidiabetic effects in STZ-induced diabetic rats. Although daily administration of vanadate alone (50 and 25 micromol x kg(-1) x day(-1) i.p.) for 2 weeks had little or no effect on glycemia, vanadate plus benzylamine reduced hyperglycemia in diabetic rats, enhanced basal and insulin-stimulated glucose transport, and upregulated GLUT4 expression in isolated adipocytes. In all, our results substantiated that acute and chronic administration of benzylamine with low dosages of vanadate have potent antidiabetic effects in rats.

Effect of ethyl esterification of phenolic acids on low-density lipoprotein oxidation

Inhibition of copper-induced low-density lipoprotein (LDL) oxidation by phenolic acids and their ethyl esters was investigated. LDL oxidation was evaluated by the hydroperoxide concentration and the chromatographic pattern of apoprotein fractions after fast protein liquid chromatography (FPLC). Antiradical properties against 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical and 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH) were also investigated, and lipophilicity determined by thin-layer chromatography. Caffeic acid at 5 microM and sinapic acid at 10 microM protected LDL against oxidation, inhibiting both hydroperoxide formation and the increase of apoprotein negative charge. Ferulic, gallic and p-hydroxy cinnamic acids were ineffective. Ethyl esterification increased the lipophilicity of the five acids, and enhanced the antioxidant properties of caffeic, sinapic and ferulic acids. Ethyl caffeate was protective at 1 microM. In contrast, gallic and p-hydroxy cinnamic ethyl esters were ineffective. Our results indicate that ethyl esterification of phenolic acids increases lipophilicity of their ethyl esters and may enable a better incorporation into the lipid layer of the LDL particle and the exertion of their antioxidant effect in the true site of lipoperoxidation. However, increasing lipophilicity is not the only mechanism able to potentiate preexisting antioxidant properties of molecules, and probably other mechanisms are implicated.

Substrates of semicarbazide-sensitive amine oxidase co-operate with vanadate to stimulate tyrosine phosphorylation of insulin-receptor-substrate proteins, phosphoinositide 3-kinase activity and GLUT4 translocation in adipose cells

It has been shown that the combination of benzylamine or tyramine and low concentrations of vanadate markedly stimulates glucose transport in rat adipocytes by a mechanism that requires semicarbazide-sensitive amine oxidase (SSAO) activity and H(2)O(2) formation. Here we have further analysed the insulin-like effects of the combination of SSAO substrates and vanadate and we have studied the signal-transduction pathway activated in rat adipocytes. We found that several SSAO substrates (benzylamine, tyramine, methylamine, n-decylamine, histamine, tryptamine or beta-phenylethylamine), in combination with low concentrations of vanadate, stimulate glucose transport in isolated rat adipocytes. Furthermore, SSAO substrates together with vanadate stimulated the recruitment of GLUT4 to the cell surface in isolated rat adipocytes. Benzylamine plus vanadate also stimulated glucose transport and GLUT4 translocation in 3T3-L1 adipocytes. Benzylamine or tyramine in combination with vanadate potently stimulated the tyrosine phosphorylation of both insulin receptor substrate (IRS)-1 and IRS-3. In contrast, benzylamine and vanadate caused only a weak stimulation of insulin receptor kinase. Benzylamine or tyramine in combination with vanadate also stimulated phosphoinositide 3-kinase activity; wortmannin abolished the stimulatory effect of benzylamine and vanadate on glucose transport in adipose cells. Furthermore, the administration of benzylamine and vanadate in vivo caused a rapid lowering of plasma glucose levels, which took place in the absence of alterations in plasma insulin. On the basis of these results we propose that SSAO activity regulates glucose transport in adipocytes. SSAO oxidative activity stimulates glucose transport via the translocation of GLUT4 carriers to the cell surface, resulting from a potent tyrosine phosphorylation of IRS-1 and IRS-3 and phosphoinositide 3-kinase activation. Our results also indicate that substrates of SSAO might regulate glucose disposal in vivo.

In vitro study of the cytotoxicity of isolated oxidized lipid low-density lipoproteins fractions in human endothelial cells: relationship with the glutathione status and cell morphology

Toxic effects of oxidized lipid compounds contained in oxidized LDL to endothelial cells are involved in the pathogenesis of atherosclerosis. Glutathione (GSH) plays an important role in the redox status of the cell and in the protective effect against oxidant injuries. However, little is known about the respective effect of these different oxidized lipid compounds toward cytotoxicity and GSH status of the cell. In this report, we isolated by high-performance liquid chromatography oxidized lipid compounds from low-density lipoproteins (LDL) oxidized by copper and we examined their effects on cultured endothelial cells. Cytotoxicity and GSH status were determined after incubation of endothelial cells with crude LDL or isolated lipid fractions derived from cholesterol, phospholipids, or cholesteryl esters. Their effects on cell morphology were also assessed. Oxidized lipids coming from cholesteryl esters (hydroperoxides or short-chain polar derivatives) induced a slight but significant GSH depletion without inducing cytotoxicity. The same species coming from phospholipids induced a more pronounced GSH depletion and a cytotoxic effect which is only present for the more polar compounds (short-chain polar derivatives) and corresponding to a total GSH depletion. In contrast, fractions containing oxysterols had a larger cytotoxic effect than their effect on GSH depletion suggesting that their cytotoxic effects are mediated by a GSH-independent pathway. All together, these data suggest that LDL-associated oxidized lipids present in copper-oxidized LDL exert cytotoxicity by an additional or synergistic effect on GSH depletion, but also by another mechanism independent of the redox status of the cell.

[Biological diagnosis of the type of liver disease in alcoholic patients with abnormal liver function tests]

OBJECTIVES

The histological diagnosis of the different stages of alcoholic liver disease is not systematic. The aim of this study was to assess whether common biological features were useful in identifying the different stages.

METHODS

One thousand twenty six alcoholic patients with liver histology and without any associated diseases or infections likely to alter serum liver tests were studied. Diagnostic analyses were performed using stepwise discriminant analysis in the entire population and in asymptomatic patients.

RESULTS

a) Serum ASAT activity levels were only normal in 39% of the patients with normal histological liver and in 14% of the patients with steatosis; b) liver failure was already present in patients with fibrosis without cirrhosis; c) betagamma block was the only biochemical parameter which confirmed the diagnosis of cirrhosis without biopsy; d) the diagnostic accuracy of common tests was weak for the diagnosis of alcoholic liver disease without cirrhosis but prothrombin time could be useful in excluding the diagnosis of cirrhosis with and without acute alcoholic hepatitis when liver biopsy is not available.

CONCLUSION

Only a prothrombin time of 80% with a negative predictive value of 94% and the presence of beta-gamma [corrected] block with a positive predictive value of 98% were useful for assessing the diagnosis of cirrhosis in all patients with alcoholic liver disease.

[Thyroid hormone determination at the Public Assistance Hospital of Paris: ordering, costs and opinions of physicians qualified in endocrinology]

OBJECTIVES

To determine the distribution of orders for hormonal tests assessing thyroid function in a hospital setting. To collect the opinion of physicians specialized in endocrinology concerning free triodothyronine (FT3) assessment.

METHODS

Using a cross-sectional survey numbers of free thyroxine (FT4), total T4 (TT4), FT3, total T3 (TT3), and TSH tests were collected from the heads of laboratory assessing thyroid function in June 95 at the Assistance Publique-Hôpitaux de Paris (AP-HP). Cost for these tests was estimated. The physicians of the AP-HP specialized in endocrinology were asked through a questionnaire for circumstances justifying FT3 test ordering.

RESULTS

Twenty-eight laboratories (93%) responded: 28455 measurements (TSH: 43%, FT4: 33%, TT4: 2%, FT3: 20%, TT3: 2%) were performed and were valued at 3.4 million French Francs. Proportions of T4 (36%) and T3 (20%) tests were lower in hospitals with an inpatient department of endocrinology than in hospitals with an outpatient clinic with specialists in endocrinology (T4: 36%; T3: 27%) or with no endocrinology unit (T4: 33%, T3: 27%); proportion of TSH tests was higher in hospitals with an inpatient endocrinology unit (respectively 44%, 40%, 32%). Forty-two endocrinologists (76%) from 21 departments answered. Follow-up of treatment with amiodarone and euthyroid sick syndrome were considered the only conditions justifying FT3 test ordering.

CONCLUSION

Though the opinion of physicians specialized in endocrinology was not uniform regarding recommendations for TT3 or FT3 tests as a first-line measurement, the cost of these tests has been estimated at 650 thousand Francs for a month at the AP-HP.

[Influence of apolipoprotein E polymorphism in alcoholic cirrhosis]

OBJECTIVE

To assess whether the polymorphism of apolipo-protein E was associated with the development of alcoholic cirrhosis and could influence the severity of liver injury evaluated by the Child-Pugh score.

METHOD

We investigated 75 alcoholic patients with a histological diagnosis of cirrhosis, with negative HBV, HCV serology and a control group of 54 subjects. Polymorphism of apolipoprotein E was performed using PCR.

RESULTS

There was no difference for the allele frequency and the genotype in the cirrhotic group and the control group. Cirrhotic patients with allele epsilon 2 had higher concentration of albumin (P = 0.01) and a higher level of apolipoprotein AII (P < 0.05) than those with allele epsilon 3. They also had a higher concentration of apolipoprotein AI than cirrhotic patients with allele epsilon 3 and epsilon 4 (P = 0.01). There was a statistical difference between the three genotype groups for prothrombin time (P = 0.01). There was no statistical difference between the three genotype groups for Child-Pugh score.

CONCLUSIONS

Polymorphism of apolipoprotein E was not associated with the development of alcoholic cirrhosis. However patients with allele epsilon 2 had better hepatocellular function.

Comparison of oxidized low-density lipoprotein toxicity on EA.hy 926 cells and human vein endothelial cells: influence of antioxidant systems

We compared the susceptibility to oxidized LDL cytotoxicity of primary human umbilical vein endothelial cells (HUVEC) and EA.hy 926 cells. EA.hy 926 endothelial cells were more susceptible than HUVEC. To determine the basis of this difference, we evaluated the enzymatic antioxidant machinery in the two cell types. The antioxidant enzyme activities of superoxide dismutase, catalase and glutathione peroxidase were significantly lower in EA.hy cells than in HUVEC: 54%, 71% and 8% of the HUVEC enzyme activities respectively. Pre-incubation of the EA.hy 926 endothelial cells with glutathione peroxidase (100 IU/ml) inhibited the cytotoxic effect of oxidized LDL. Superoxide dismutase (300 or 600 IU/ml) and catalase (300 or 600 IU/ml) had no effect. Compared to HUVEC, the higher susceptibility of EA.hy 926 cells to oxidized LDL induced injury may be associated with lower antioxidant defences, in particular with lower glutathione peroxidase activity which is known to eliminate lipid hydroperoxides and thereby to prevent the formation of damaging peroxyl radical intermediates.

Oxidized low-density lipoprotein induces the production of interleukin-8 by endothelial cells

The concentration of interleukin-8 (IL-8) and RANTES was measured in culture supernatants of human EA.hy 926 endothelial cells incubated with oxidized low-density lipoproteins (LDL). Oxidized LDL induced a 3-fold increase in IL-8 production (p < 0.01), whereas RANTES was not detected. Native LDL did not stimulate IL-8 production. IL-8 production in oxidized-LDL-treated cells was mediated by reactive oxygen species, as it was partially inhibited by catalase and completely inhibited by glutathione peroxidase and N-acetylcysteine (p < 0.01).

A method for simultaneous determination of plasma and erythrocyte antioxidant status. Evaluation of the antioxidant activity of vitamin E in healthy volunteers

1. Since oxygen free radicals are directly involved in a variety of pathologies such as atherosclerosis, diabetes mellitus, inflammation and/or when a deficit of defences of the organism against radicals occurs, we developed a suitable and simple method to determine both the erythrocyte sensitivity to an oxidative stress and plasma antioxidant protective capacity. 2. This test is based on the introduction at 37 degrees C of a radical initiator, 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH), within an erythrocyte suspension leading to a membrane alteration and ultimately to haemolysis. The latter can be quantified by determining the lacticodeshydrogenase activity released in the medium. The erythrocyte sensitivity to haemolysis and the volume of plasma inhibiting 50% of the haemolysis were determined. 3. Intra-assay CVs were 1.9% for erythrocyte sensitivity to oxidative stress and 3.4% for inhibitory 50% plasma volume. Inter-assay CVs for both erythrocyte sensitivity and inhibitory 50% plasma volume were 4%. 4. The reliability of this method was assessed and applied to test the protective effect of vitamin E, a well known antioxidant agent, in six healthy volunteers. Two weeks after daily administration of 500 mg of vitamin E, the mean plasma vitamin E concentration increased by 41% from 10.7 +/- 2.0 mg l-1 before treatment (P < 0.05). As the vitamin E concentration increased, the mean inhibitory 50% plasma volume and the percentage of haemolysed erythrocytes decreased respectively by 29% from 3.35 +/- 0.5 microliter (P < 0.05) and 18% from 71.5 +/- 3.8% (P < 0.05). No significative variation of these parameters was observed in six adult men without vitamin E supplementation. 5. Thus, this global and simple test permits an antioxidant status evaluation of a patient. It can be applied to various pathologies and allows the potency of new antioxidant molecules to be evaluated.

Decreased erythrocyte deformability in glycogen storage disease

Liver glycogen storage diseases (GSD) are disorders associated with severe dyslipidaemia which can induce cell membrane alterations and possibly reduced cell deformability. Since decreased erythrocyte deformability is known to disturb blood flow in capillaries and may promote ischaemic diseases, this study was designed to investigate erythrocyte deformability using a new filtration system, the Cell Transit Analyser (CTA), and to examine lipid compounds in the blood of 23 patients affected with GSD, aged from 1 to 20 years and 18 controls aged from 1 to 17 years. The patients showed a mixed hyperlipidaemia with predominant hypertriglyceridaemia and an increase in erythrocytes mean transit times (TT) due to the presence of more rigid erythrocytes subpopulations when compared to controls. Thus the erythrocyte rigidity, in addition to the lipid abnormalities must be taken into account for long-term evolution of GSD patients. Moreover this cellular alteration may contribute to shortened erythrocyte survival.

Blood lipids and rheological modifications in glycogen storage disease

OBJECTIVES

Hyperlipidemia is a feature of liver glycogen storage disease (GSD). Recent studies have suggested that rheological mechanisms such as elevated erythrocyte aggregation may be involved in the pathogenesis of ischemic syndromes associated with hyperlipidemia.

DESIGN AND METHODS

We investigated erythrocyte aggregation, lipids, and circulatory proteins in the blood of 24 patients affected with GSD, aged from 1 to 23 years (mean = 8) and 26 controls aged from 1 to 28 years (mean = 9).

RESULTS

The aggregation results were much higher in patients than controls. The lipid data showed a mixed hyperlipidemia with predominant hypertriglyceridemia, low HDL-C, apoA-I and LpA-I/A-II, and high apoB as compared with controls. However, the LpA-I was not significantly different from controls.

CONCLUSIONS

In conclusion, patients with GSD presented hyperlipidemia and elevated erythrocyte aggregation such that they are at long-term risk of ischemic complications.

Prevalence of cholelithiasis according to alcoholic liver disease: a possible role of apolipoproteins AI and AII

Moderate alcohol intakes decreases the risk of gallstones; in contrast, the prevalence of gallstones is increased in patients with alcoholic cirrhosis. The aims of this prospective study were to assess the prevalence of cholelithiasis among drinkers according to the histological severity of liver disease, and to estimate the importance of serum apolipoproteins AI and apolipoprotein AII as risk factors for gallstones. Among the 320 drinkers included, 53 patients had cholelithiasis. The prevalence increased (p < 0.0001) from 5% in patients with normal liver (1 of 22) and 6% in patients with steatosis only (3 of 47) to 13% in patients with fibrosis (7 of 54), reaching 27% among patients with biopsy-proven cirrhosis (28 of 103). Among patients with clinically obvious cirrhosis on whom biopsy was not performed mainly because of the severity of liver disease, the prevalence of cholelithiasis reached a maximum of 46% (6 of 13). Among drinkers with nonsevere liver disease, patients with cholelithiasis were older (59 +/- 9 years, mean +/- SD vs. 45 +/- 11, p = 0.003) with lower apolipoprotein AI (118 +/- 37 vs. 163 +/- 45 mg/dl; p = 0.002) and apolipoprotein AII (30 +/- 12 vs. 53 +/- 20 mg/dl; p = 0.0002) in comparison with patients without cholelithiasis. These differences persisted after considering by multiple logistic regression analysis, sex, and ideal body weight. Alcohol consumption during the last 5 years was lower in patients with cholelithiasis (83 g/day) in comparison with patients without cholelithiasis (142 g/day; p = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Description generation of abnormal densities found in radiographs

In this paper we present a system for describing renal stones found in radiographs. The system generates descriptions that adhere to those generated by radiologists. The descriptions are formulated by discovering the spatial relationships that exist between the major organs and the renal stones. The system consists of three major components. The first is the image processing component which is responsible for locating the stone. The second component is the inference network minimization component which determines which spatial relationships, of all those that exist between the stone and the organs, is the most descriptive. The third component is the natural language generation component which is responsible for translating the spatial relationships into appropriate medical terminology. We will illustrate all these components on several examples.

A simple biological index for detection of alcoholic liver disease in drinkers

To make liver biopsy unnecessary in certain cases, PGA (P, prothrombin time; G, gamma-glutamyl transpeptidase; A, apoliprotein AI), a simple biological index combining a specific test for severe liver disease (prothrombin time), a sensitive test of alcoholic liver disease (serum gamma-glutamyl transpeptidase), and a test for liver fibrosis (serum apolipoprotein AI), was evaluated in a training sample of 333 drinkers and validated in 291 other drinkers. All patients underwent an intercostal liver biopsy, and the specimen was independently read by two pathologists. The PGA index varied from 0 to 12. When PGA was less than or equal to 2, the probability of cirrhosis was 0% and the probability of normal liver or minimal changes 83%. Conversely, when PGA was greater than or equal to 9, the probability of normal liver or minimal changes was 0% and the probability of cirrhosis 86%. These values did not vary between training and validation periods, between asymptomatic vs. symptomatic subjects or between PGA at admission vs. PGA 1 week later. This index could be useful for general practitioners in identifying subjects at high risk for severe alcoholic liver disease.

A simple biological index for detection of alcoholic liver disease in drinkers

To make liver biopsy unnecessary in certain cases, PGA (P, prothrombin time; G, gamma-glutamyl transpeptidase; A, apoliprotein AI), a simple biological index combining a specific test for severe liver disease (prothrombin time), a sensitive test of alcoholic liver disease (serum gamma-glutamyl transpeptidase), and a test for liver fibrosis (serum apolipoprotein AI), was evaluated in a training sample of 333 drinkers and validated in 291 other drinkers. All patients underwent an intercostal liver biopsy, and the specimen was independently read by two pathologists. The PGA index varied from 0 to 12. When PGA was less than or equal to 2, the probability of cirrhosis was 0% and the probability of normal liver or minimal changes 83%. Conversely, when PGA was greater than or equal to 9, the probability of normal liver or minimal changes was 0% and the probability of cirrhosis 86%. These values did not vary between training and validation periods, between asymptomatic vs. symptomatic subjects or between PGA at admission vs. PGA 1 week later. This index could be useful for general practitioners in identifying subjects at high risk for severe alcoholic liver disease.

[Anti-radical enzymes, oxygenated free radicals and lipoperoxydation in rheumatoid polyarthritis. Effects of treatment with D-penicillamine]

Three aspects of the action of oxygenated free radicals were studied in 10 controls and 20 patients with rheumatoid arthritis, 11 not treated and 9 treated with D-penicillamine. Free radical production was evaluated in whole blood, malondialdehyde was measured in plasma, the concentration of antiradicular enzymes (copper and manganese superoxide dismutase, catalase and glutathion peroxydase) in hemolysate, platelets and plasma and copper superoxide dismutase activity in a chloroform erythrocyte extract. Only patients treated with D-penicillamine showed a significant decrease in the concentration of platelet anti-radicular enzymes and plasma manganese superoxide dismutase. The involvement of oxygenated free radicals in the pathophysiology of rheumatoid arthritis and in the mechanism of action of D-penicillamine in this pathology is discussed.

Serum apolipoprotein A-I in alcoholic patients with chronic calcifying pancreatitis

Serum apolipoprotein A-I measurement was compared in alcoholic patients according to presence or absence of chronic pancreatitis and liver fibrosis. Among alcoholic patients without liver disease, apolipoprotein A-I was significantly lower in patients with chronic pancreatitis (157 +/- 70 mg/dl) than in patients without pancreatitis (209 +/- 74 mg/dl, p less than 0.001). In cirrhotic patients, apolipoprotein A-I was lower in patients with chronic pancreatitis (82 +/- 35 mg/dl) than in patients without pancreatitis (102 +/- 45 mg/dl), but this difference was not significant. The decrease of serum apolipoprotein A-I was independent of nutritional parameters whether or not there was cirrhosis. Immunohistochemical study of pancreatic samples with chronic pancreatitis showed that apolipoprotein A-I was located in the pancreatic fibrosis whereas lobules were unstained. This study suggests that apolipoprotein A-I is trapped by the pancreatic extracellular matrix and that this sequestration might explain, in part, the decrease of the serum apolipoprotein A-I.