Tumor necrosis factor-alpha antagonism improves vasodilation during hyperinsulinemia in metabolic syndrome

OBJECTIVE—Obesity is associated with chronic inflammation due to overproduction of proinflammatory cytokines, including tumor necrosis factor (TNF)-α. We assessed the effects of TNF-α neutralization by infliximab on vascular reactivity during hyperinsulinemia in obesity-related metabolic syndrome.RESEARCH DESIGN AND METHODS—Vascular responses to intra-arterial infusion of acetylcholine (ACh) and sodium nitroprusside (SNP) were assessed in patients with metabolic syndrome, before and after administration of infliximab.RESULTS—Patients had blunted vasodilator responses to ACh and SNP during hyperinsulinemia compared with control subjects; a potentiation of the responsiveness to both ACh and SNP, however, was observed in patients following infliximab. The antioxidant vitamin C improved the vasodilator response to ACh in patients with metabolic syndrome, but its effect was not further enhanced by concurrent administration of infliximab.CONCLUSIONS—TNF-α neutralization ameliorates vascular reactivity in metabolic syndrome during hyperinsulinemia, likely in relation to decreased oxidative stress, thereby suggesting an involvement of inflammatory cytokines in vascular dysfunction of these patients.Central obesity is associated with low-grade, chronic inflammation, which might affect insulin action and thus contribute to both insulin resistance and vascular dysfunction characteristic of metabolic syndrome. Among various inflammatory cytokines, tumor necrosis factor (TNF)-α seems to play an important role in the pathophysiology of insulin resistance. However, no clear link has been established between the vascular pathology of metabolic syndrome and a particular inflammatory cytokine in humans. This study, therefore, assessed the effects of TNF-α neutralization by the monoclonal antibody infliximab on vascular reactivity during hyperinsulinemia in metabolic syndrome.     

Evaluation of the preventative effects exerted by Lactobacillus fermentum in an experimental model of septic shock induced in mice

The preventative effects of the probiotic Lactobacillus fermentum CECT5716 were evaluated in the lipopolysaccharide (LPS) model of septic shock in mice. The probiotic was administered suspended in drinking water at the final concentration of 108 colony-forming units/ml for 2 weeks before the induction of an endotoxic shock by an intraperitoneal injection of LPS (400 microg/200 microl per mouse). Blood and different organs were collected after 24 h to evaluate the severity of the endotoxic shock and the preventative effects of the probiotic. L. fermentum reduced TNF-alpha levels in blood, which promotes the major alterations observed during septic shock, as well as the infiltration of activated neutrophils into the lungs. Furthermore, free radical overproduction and oxidative stress were associated with a significant decrease in hepatic glutathione levels in septic mice, and with an excessive NO production attributed to the induction of the inducible isoform of NO synthase (iNOS). In fact, hepatic glutathione levels were significantly increased in the group of mice receiving the probiotic, and the increased iNOS expression both in the colon and lungs was down-regulated in those mice treated with L. fermentum. Finally, pre-treatment with L. fermentum may also exert its protective action modulating the expression of different cytokines in splenocyte-derived T cells such us IL-2, IL-5, IL-6 or IL-10. In conclusion, pre-treatment with L. fermentum may exert its protective action against LPS-induced organ damage in mice by a combination of several actions including its antioxidant properties and by reduction of the synthesis of the pro-inflammatory TNF-alpha and IL-6.     

Microtox solid phase test: Effect of diluent used in toxicity test

Microtox solid phase test is an acute toxicity test for solid matrices based on inhibition of natural bioluminescence of the marine bacterium Vibrio fischeri. Protocols developed to overcome the effects of confounding factors are proposed in the literature that differs by important practical and methodological issues. This work focused on diluents used for sediment resuspension and dilution. Two artificial seawaters, one natural seawater and two phosphate buffer solutions, were compared. The results showed that toxicity data obtained using different diluents were not comparable and that test sensitivity is highest using 0.1M phosphate buffer solution. The effects of medium on test organism were also investigated, in order to verify the capacity of media to maintain bioluminescence. The results underlined the importance of pH and Eh to explain the observed differences in toxicity.     

Calpain activity contributes to the control of SNAP-25 levels in neurons

Calpains are a family of calcium-dependent proteases with abundant expression in the CNS, and potent in cleaving some synaptic components. Assessment of calpain activity by its fluorescent substrate, Boc-Leu-Met-CMAC, revealed that cultured neurons display a significant level of constitutive enzyme activity. Notably, calpain activity differs in distinct neuronal populations, with a significantly higher level of activity in GABAergic cells. Using selectively-enriched cultures of fast-spiking GABAergic interneurons, we show that calpain activity partially contributes to the post-translational down regulation of SNAP-25, a calpain substrate, in differentiated GABA cells. In addition, we demonstrate that SNAP-25 is cleaved by calpain in response to acute seizures induced by intraperitoneal kainate injection in vivo. These data indicate that calpains in neurons are active even at physiological calcium concentrations and that different levels of calpain activation in selected neuron subtypes may contribute to the pattern of synaptic protein expression.     

Intramuscular Neridronate in Postmenopausal Women with Low Bone Mineral Density

Compliance to osteoporosis treatment with oral bisphosphonates is very poor. Intermittent intravenous bisphosphonate is a useful alternative, but this route is not readily available. Neridronate, a nitrogen-containing bisphosphonate that can be given intramuscularly (IM), was tested in a phase 2 clinical trial in 188 postmenopausal osteoporotic women randomized to IM treatment with 25 mg neridronate every 2 weeks, neridronate 12.5 or 25 mg every 4 weeks, or placebo. All patients received calcium and vitamin D supplements. The patients were treated over 12 months with 2-year posttreatment follow-up. After 12-month treatment, all three doses were associated with significant bone mineral density (BMD) increases at both the total hip and spine. A significant dose–response relationship over the three doses was observed for the BMD changes at the total hip but not at the spine. Bone alkaline phosphatase decreased significantly by 40–55% in neridronate-treated patients, with an insignificant dose–response relationship. Serum type I collagen C-telopeptide decreased by 58–79%, with a significant dose–response relationship (P < 0.05). Two years after treatment discontinuation, BMD declined by 1–2% in each dose group, with values still significantly higher than baseline at both the spine and the total hip. Bone turnover markers progressively increased after treatment discontinuation, and on the second year of follow-up the values were significantly higher than pretreatment baseline. The results of this study indicate that IM neridronate might be of value for patients intolerant to oral bisphosphonates and unwilling or unable to undergo intravenous infusion of bisphosphonates.     

Double contrast small-bowel radiography in the preoperative assessment of Crohn’s disease: Is it still useful?

PURPOSE: To evaluate the usefulness of double contrast small-bowel radiography (SBR) in the preoperative assessment of patients with Crohn's disease (CD). METHODS: Thirty-nine consecutive patients who underwent surgery for CD between 2000 and 2004, preceded by a preoperative small-bowel series evaluation, were enrolled in our study. The radiologic findings were compared with the intraoperative findings. RESULTS: Small-bowel radiography was associated with good specificity and sensitivity for the detection of stenosis. Although its main limitation was a remarkable overestimation of stenosis, the main indications for surgery were always confirmed. Sensitivity and specificity were lower for the detection of internal fistulas and the correlation was significant only for SBR performed within 3 months of the operation; however, the concordance between radiological and operative findings was greater. No correlation was observed for the detection of an abdominal mass. CONCLUSIONS: Small-bowel radiography is still reliable for evaluating stenoses and internal fistulas. However, magnetic resonance imaging or computed tomography is mandatory to evaluate an abdominal mass.     

Comparison of endoscopic ultrasonography and magnetic resonance cholangiopancreatography in the diagnosis of pancreatobiliary diseases: a prospective study

OBJECTIVES: To compare the diagnostic value of endoscopic ultrasonography (EUS) and magnetic resonance cholangiopancreatography (MRCP) in: (a) patients with a dilated biliary tree unexplained by ultrasonography (US) (group 1), and (b) the diagnosis of choledocholithiasis in patients with nondilated biliary tree (group 2). METHODS: Patients were prospectively evaluated with EUS and MRCP. The gold standard used was surgery or EUS-FNA and ERCP, intraoperative cholangiography, or follow-up when EUS and/or MRCP disclosed or precluded malignancy, respectively. Likelihood ratios (LR) and pretest and post-test probabilities for the diagnosis of malignancy and choledocholithiasis were calculated. RESULTS: A total of 159 patients met one of the inclusion criteria but 24 of them were excluded for different reasons. Thus, 135 patients constitute the study population. The most frequent diagnosis was choledocholithiasis (49% in group 1 and 42% in group 2, P= 0.380) and malignancy was more frequent in group 1 (35%vs 7%, respectively, P < 0.001). When EUS and MRCP diagnosed malignancy, its prevalence in our series (35%) increased up to 98% and 96%, respectively, whereas it decreased to 0% and 2.6% when EUS and MRCP precluded this diagnosis. In patients in group 2, when EUS and MRCP made a positive diagnosis of choledocholithiasis, its prevalence (42%) increased up to 78% and 92%, respectively, whereas it decreased to 6% and 9% when any pathologic finding was ruled out. CONCLUSIONS: EUS and MRCP are extremely useful in diagnosing or excluding malignancy and choledocholithiasis in patients with dilated and nondilated biliary tree. Therefore, they are critical in the approach to the management of these patients.