Liver involvement in obese children. Ultrasonography and liver enzyme levels at diagnosis and during follow-up in an Italian population

Our aim was to evaluate incidence and risk factors of liver involvement in obese Italian children as assessed by both ultrasonographic and biochemical parameters. In seventy-five consecutive obese children (age 9.5 +/- 2.9 years, males/females 41/34), serum levels of enzymes and ultrasonography of the liver were evaluated. Tests were repeated one, three, and six months after starting a moderate hypocaloric diet and an exercise program. Three obese children who were found to have chronic viral hepatitis were excluded from the study. Thirty-eight of 72 (53%) obese children had an ultrasonographic image of bright liver consistent with liver steatosis. The latter was severe in nine children, moderate in 16, and mild in 13. Eighteen obese children (25%) had elevated transaminase levels. Bright liver and hypertransaminasemia were not due to any of the most common causes of liver disease. Both were rapidly responsive to loss of weight, confirming that liver involvement was secondary to obesity and that steatosis or steatohepatitis rather than fibrosis were involved. Obesity duration not more than three years (odds ratio = 4.77), a higher degree of obesity (odds ratio = 2.09), and hypertransaminasemia (odds ratio = 2.15) appeared as important predictive factors of liver involvement at ultrasonography. Incidence of liver involvement assessed by means of ultrasonography is significantly higher than that revealed by measurement of serum liver enzymes. A short duration of obesity emerged as a potentially new risk factor of liver involvement in the pediatric obese population and needs to be confirmed in future studies.

Enterotoxicity and cytotoxicity of Vibrio parahaemolyticus thermostable direct hemolysin in in vitro systems

Vibrio parahaemolyticus is a marine bacterium known to be a common cause of seafood gastroenteritis worldwide. The thermostable direct hemolysin (TDH) has been proposed to be a major virulence factor of V. parahaemolyticus. TDH causes intestinal fluid secretion as well as cytotoxicity in a variety of cell types. In this study, we investigated the interplay between the hemolysin's enterotoxic and cytotoxic effects by using both human and rat cell monolayers. As revealed by microspectrofluorimetry, the toxin causes a dose-dependent increase in intracellular free calcium in both Caco-2 and IEC-6 cells. This effect was reversible only when low toxin concentrations were tested. The TDH-activated ion influx pathway is not selective for calcium but admits ions such sodium and manganese as well. Furthermore, in the same range of concentration, the hemolysin triggers a calcium-dependent chloride secretion. At high concentrations, TDH induces a dose-dependent but calcium-independent cell death as assessed by functional, biochemical, and morphological assays.

Delayed initiation of subcutaneous insulin therapy after failure of oral glucose-lowering agents in patients with Type 2 diabetes: a population-based analysis in the UK

AIMS

The aim of this retrospective cohort study was to estimate the time to insulin initiation in patients with Type 2 diabetes inadequately controlled on oral glucose-lowering agents (OGLAs).

METHODS

Insulin-naïve patients failing on OGLAs were identified from The Health Improvement Network database, which collects records from general practices throughout the UK. Patients were included if they were aged > or = 40 years, had concomitant prescriptions for > or = 2 OGLAs, and > or = 1 year of available records prior to the first occurrence of HbA(1c) > or = 8.0% after > or = 90 days of OGLA polytherapy at > or = 50% of maximum recommended dosages.

RESULTS

A total of 2501 eligible patients with Type 2 diabetes who had an HbA(1c) above the OGLA failure threshold of > or = 8.0% were identified (54.0% male; 30.9% aged 60-69 years). It was estimated that if all the eligible patients were followed for 5 years, 25% would initiate insulin within 1.8 years of OGLA failure (95% CI 1.6-2.0), and 50% within 4.9 years (95% CI 4.6-5.8). The presence of diabetes-related complications had no substantial impact on the time to insulin initiation.

CONCLUSIONS

This study found that 25% of patients with Type 2 diabetes had insulin initiation delayed for at least 1.8 years, and 50% of patients delayed starting insulin for almost 5 years after failure of glycaemic control with OGLA polytherapy, even in the presence of diabetes-related complications. Interventions that reduce this delay to insulin initiation are required to help achieve and maintain recommended glycaemic targets in patients with Type 2 diabetes.

Contribution of P1-(A2b subtype) and P2-purinoceptors to the control of vascular tone in the rat isolated mesenteric arterial bed

1. The direct vascular effects of adenosine and ATP were compared in the isolated and perfused mesenteric arterial bed of the rat. The actions of analogues of adenosine and ATP were also examined. 2. In preparations at basal tone, adenosine lacked vasoconstrictor actions, while ATP elicited dose-dependent vasoconstrictor responses. When the tone of preparations was raised by adding methoxamine to the perfusate, adenosine and its stable analogue, 2-chloroadenosine (2-CADO) elicited dose-dependent vasodilation. The A2 adenosine receptor agonist, 5'-N-ethylcarboxamidoadenosine (NECA) was active at lower doses than adenosine, while the A2a-selective agonist, CGS 21680 and the selective A1 agonist, N6-cyclopentyladenosine (CPA) failed to induce vasodilatation. ATP and its analogue, 2-methylthio ATP, elicited dose-dependent vasodilatation at doses 400 fold lower than adenosine. 3. Vasodilator responses to adenosine and 2-CADO were sensitive to antagonism by 1 microM 8-sulphophenyltheophylline (8-SPT) and were unaffected by inhibition of nitric oxide synthase by N omega-nitro-L-arginine methyl ester (L-NAME). In contrast, vasodilator responses to ATP were not sensitive to antagonism by 8-SPT and were almost abolished by L-NAME treatment. 4. These results indicate that in the rat mesenteric arterial bed, while both adenosine and ATP participate in the purinergic control of vascular tone, adenosine appears to be a weaker vasodilator than ATP and lacks vasoconstrictor action. A2b adenosine receptors account for the adenosine-induced vasodilatation which is independent of the production of nitric oxide.

Ischaemic preconditioning of the vasculature: an overlooked phenomenon for protecting the heart?

Exposing the heart to brief episodes of ischaemia protects the myocardium and vascular endothelial cells against functional damage and cell death caused by subsequent prolonged ischaemia. Elucidation of the mechanisms that are involved in this phenomenon known as 'ischaemic preconditioning' and identification of drugs that mimic the protective response have the potential to improve the prognosis of myocardial infarction and other cardiac syndromes dramatically. This article focuses on recent findings on the effects of ischaemic preconditioning of the coronary vasculature, which highlight the endothelium as an important target for a successful therapeutic approach to myocardial ischaemia-reperfusion injury.

Characterisation of subtypes of the P2X and P2Y families of ATP receptors in the foetal human heart

ATP exerts a variety of actions within the myocardium, including the regulation of coronary vascular tone and modulation of the autonomic control of the heart. In order to characterise the ATP receptor subtypes involved in these effects, degenerate oligonucleotides were used to clone receptors of both P2X and P2Y families from the human foetal heart. About 1 ng of "Quick-Clone cDNA" from foetal human heart was subjected to amplification with two pairs of degenerate oligonucleotides designed to amplify subtypes of the P2X and P2Y receptor families by means of PCR reactions. The sequence analysis of 34 and 29 clones of the P2X and P2Y receptor families, respectively, demonstrated that P2X1, P2X3 and P2X4 subtypes are present in the human foetal heart together with P2Y6, P2Y2 and P2Y4 receptors. P2X1 and P2Y4 receptor subtypes were here characterised for the first time in the human foetal heart. The present study provides the first molecular characterisation of ATP receptors in the foetal human heart. The results show that many P2 receptor subtypes are expressed in the foetal human heart, perhaps contributing to developmental processes as well as to the activity of the foetal heart.

Human intestinal cryptosporidiosis: secretory diarrhea and enterotoxic activity in Caco-2 cells

A cell line model to detect enterotoxic effect was used to test fecal specimens of patients with enteric cryptosporidiosis. Fecal samples were obtained from 11 patients with Cryptosporidium diarrhea, and osmotic gap was determined. Caco-2 cell monolayers grown on filters were mounted in Ussing chambers, and electrical parameters were measured before and after the addition of fecal supernatant. A significant increase in short-circuit current was seen in 9 of 11 specimens. The enterotoxic effect was time- and dose-dependent, saturable, and Cl(-)- and Ca(2+)-dependent. Fecal osmotic gap was consistent with secretory diarrhea in the 9 enterotoxin-positive but not in the 2 enterotoxin-negative samples. In conclusion, a cell line model for studying the pathophysiology of enteric cryptosporidiosis was established. Enterotoxic activity was observed in most patients with enteric cryptosporidiosis and was strictly associated with secretory diarrhea.

The management of portal hypertension in cystic fibrosis

We have found that with proper selection and preoperative preparation, a major portosystemic shunt can be done with considerable safety in a majority of cystic fibrosis patients and thus provide them with significant palliation and improved quality of life.

Evidence for a P2-purinoceptor mediating vasoconstriction by UTP, ATP and related nucleotides in the isolated pulmonary vascular bed of the rat

1. The vasoconstrictor effects of uridine 5'-triphosphate (UTP), uridine 5'-diphosphate (UDP), uridine 5'-monophosphate (UMP) and uridine were tested in the isolated pulmonary vascular bed of the rat. Comparison was made with the effects of adenine nucleotides, adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), adenosine 5'-monophosphate (AMP) and with adenosine. The effect of P2x-purinoceptor desensitization and blockade was compared on the vascular responses to uracil and adenine nucleotides. 2. At doses ranging from 10(-8) to 10(-5) mol, UTP elicited dose-dependent vasoconstriction. UDP was equiactive to UTP, while UMP and uridine did not show vasomotor activity. Similarly, ATP showed dose-related vasoconstrictor activity. ADP was less potent than ATP in eliciting vasoconstriction, while AMP was active only at the higher doses tested and adenosine was ineffective. 3. Vasoconstriction was produced by ATP analogues with the following order of potency: alpha, beta-methylene ATP > ATP gamma S > beta, gamma-methylene ATP > 2-methylthio ATP > or = ATP. 4. Desensitization of P2x-purinoceptors by the selective agonist alpha, beta-methylene ATP did not modify the vasoconstrictor activity of UTP and UDP and only partially reduced vasoconstrictor responses to ATP, while it abolished vascular responses to alpha, beta-methylene ATP itself. 5. The antagonists of P2-purinoceptors, suramin and pyridoxalphosphate-6-azophenyl-2', 4'-disulphonic acid (PPADS), did not affect vascular responses to UTP and UDP, but reduced vasoconstriction evoked by beta, gamma-methylene ATP and ATP by about 70 and 30%, respectively. 6. This study demonstrates that uracil nucleotides, UTP and UDP, elicit vasoconstriction in the rat pulmonary vascular bed. In addition to confirming the presence of classical P2x-purinoceptors, these results also suggest the presence of a distinct purinoceptor subtype which mediates UTP- and ATP- evoked vasoconstriction in the rat pulmonary circulation.

Production of Escherichia coli STa-like heat-stable enterotoxin by Citrobacter freundii isolated from humans

Citrobacter species are often present in the stools of children and are generally considered a normal component of the intestinal microflora. Previous reports suggested that they might act as enteric pathogens. Aiming at defining the role of Citrobacter species in inducing diarrhea, we looked for their presence in the stools of 328 children with diarrhea and in 108 controls. Citrobacter strains were isolated from 46 patients (14%) and 7 controls (6.5%) (P less than 0.05). All isolates were tested for heat-stable (ST) and heat-labile (LT) enterotoxin. No LT-producing organisms were found. Three C. freundii strains, all isolated from children with diarrhea, elaborated an enterotoxin detected by the suckling mouse assay. A crude extract was prepared by acetone precipitation and a sequential ultrafiltration technique. The enterotoxin was heat stable, and its estimated molecular weight was between 2,000 and 10,000. Citrobacter enterotoxin was soluble in methanol and stable at acid and neutral pHs but not above pH 8, and its activity was destroyed by treatment with 2-mercaptoethanol. Citrobacter enterotoxin was inactive in the 18-h rabbit ileal loop test. All these characteristics closely resemble STa produced by Escherichia coli. The time course of Citrobacter enterotoxin-induced intestinal secretion in suckling mice was similar to that of E. coli STa. The enterotoxin produced by C. freundii cross-reacted with monoclonal antibodies raised against E. coli STa. These results suggest that C. freundii is capable of inducing diarrhea through the production of an E. coli-like STa, and its presence in the stools of patients with diarrhea should be considered as that of a possible etiologic agent.

Validation of viscoelastic coagulation tests during cardiopulmonary bypass

BACKGROUND

Viscoelastic point-of-care tests such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are increasingly used to guide hemostatic therapy after cardiac surgery. The aim of this study was to assess their clinical utility during cardiopulmonary bypass to predict postbypass coagulation status and to guide therapy.

METHODS

In this prospective study, TEG and ROTEM tests were performed in 52 adult patients undergoing elective cardiac surgery at two time points: near the end of cardiopulmonary bypass and after heparin reversal with protamine. The 95% confidence intervals of the mean difference were compared with a prespecified clinically relevant limit of ± 20% of the value after protamine.

RESULTS

Both viscoelastic fibrinogen assays were well within the prespecified clinically relevant limit (≥ 79% of patients). The laboratory Clauss fibrinogen was much lower during cardiopulmonary bypass than after protamine (mean difference 1.2 g L(-1) , 95% CI 1.03-1.4, which was outside a clinically acceptable difference. For intrinsically activated tests, clotting times (CT) were different and outside the prespecified limit on TEG (mean difference -1.2 min, 95% CI -1.8 to -0.6) but not on ROTEM (mean difference 2.3 sec, 95% CI -8.6 to 13.2), while clot strength was well within the clinical limit on both devices (≥ 94% of patients). For extrinsically activated tests, clot strength on both TEG and ROTEM was within the pre-specified limit in 98% of patients.

CONCLUSIONS

Results from TEG and ROTEM tests performed toward the end of cardiopulmonary bypass are similar to results after reversal of heparin. Amplitudes indicating clot strength were the most stable parameters across all tests, whereas CT showed more variability. In contrast, laboratory testing of fibrinogen using the Clauss assay was essentially invalid during cardiopulmonary bypass.

Rhein: an anthraquinone that modulates superoxide anion production from human neutrophils

Rhein (4,5-dihydroxyanthraquinone-2-carboxylic acid), the active metabolite of diacetylrhein, which has been reported as an effective antirheumatic drug in man, inhibited superoxide anion production from human neutrophils challenged with N-formylmethionyl-leucyl-phenylalanine (FMLP: IC50, 2 x 10(-5) M) and A23186 (IC50, 10(-5) M), but not with phorbol myristate acetate. In the same concentration range (10(-6)-10(-3) M), the drug did not affect oxy-radical production by a cell-free hypoxanthine-xanthine oxidase system and exerted weak inhibitory effects on FMLP-evoked lysosomal enzyme release. Rhein inhibitory effects on neutrophil functioning may contribute to the overall therapeutic activity of the parent drug, diacetylrhein.

Regulation of vascular tone by UTP and UDP in isolated rat intrapulmonary arteries

Vasoconstrictor and vasodilator responses of isolated rat intrapulmonary arteries to the pyrimidine nucleotides UTP and UDP were evaluated and compared with vascular responses to ATP and its analogues. UTP and UDP (1-500 microM) were equipotent in inducing concentration-dependent vasoconstriction, unaffected by the P2 receptor antagonists suramin (100 microM) and Reactive blue 2 (50 microM); ATP (10-500 microM) produced weaker vasoconstriction. UTP and UDP lacked vasodilator activity, while ATP and its analogue 2-methylthio ATP evoked endothelium-dependent vasodilatation. These results indicate that UTP and UDP evoke vasoconstriction of rat intrapulmonary arteries whereas ATP is predominantly a vasodilator at the same arteries. Furthermore, the pharmacological profile of the native UTP/UDP receptor differs from that of the known P2Y2, P2Y4 and P2Y6 recombinant receptors for pyrimidine nucleotides.

Focal lesions induce large-scale percolation of sleep-like intracerebral activity in awake humans

Focal cortical lesions are known to result in large-scale functional alterations involving distant areas; however, little is known about the electrophysiological mechanisms underlying these network effects. Here, we addressed this issue by analysing the short and long distance intracranial effects of controlled structural lesions in humans. The changes in Stereo-Electroencephalographic (SEEG) activity after Radiofrequency-Thermocoagulation (RFTC) recorded in 21 epileptic subjects were assessed with respect to baseline resting wakefulness and sleep activity. In addition, Cortico-Cortical Evoked Potentials (CCEPs) recorded before the lesion were employed to interpret these changes with respect to individual long-range connectivity patterns. We found that small structural ablations lead to the generation and large-scale propagation of sleep-like slow waves within the awake brain. These slow waves match those recorded in the same subjects during sleep, are prevalent in perilesional areas, but can percolate up to distances of 60 mm through specific long-range connections, as predicted by CCEPs. Given the known impact of slow waves on information processing and cortical plasticity, demonstrating their intrusion and percolation within the awake brain add key elements to our understanding of network dysfunction after cortical injuries.

FMLP-activated neutrophils evoke histamine release from mast cells

Human neutrophils, having been activated by the chemotactic peptide N-formylmethionyl-leucyl-phenylalanine (FMLP), evoke histamine release from rat serosal mast cells. The release is dependent on FMLP concentration and it can be inhibited by disodium cromoglycate and by a flavonoid, silymarin, which displays free radical scavenging properties. Silymarin inhibition of neutrophil-mediated histamine release is dose-dependent. These results further stress the concept of a neutrophil-mast cell interaction, which may be involved in inflammatory processes.

Prejunctional prostanoid receptors on cardiac adrenergic terminals belong to the EP3 subtype

1. The effects of prostaglandin E2 (PGE2) and of several synthetic prostanoids on the cardiac response to sympathetic nerve stimulation in guinea-pig atria have been evaluated. 2. PGE2 (0.01-100 nM), sulprostone (0.01-100 nM) and misoprostol (0.1-100 nM), but not butaprost (0.1-100 nM), dose-dependently reduced the increase in cardiac contractility induced by electrical field stimulation of sympathetic terminals. 3. The EP1 antagonist AH6809 (1 microM) did not modify the inhibition of cardiac response induced by PGE2, sulprostone and misoprostol. 4. In preparations preloaded with [3H]-noradrenaline, tritium overflow induced by electrical field stimulation was greatly and significantly reduced by 100 nM PGE2 and by 100 nM sulprostone. 5. These results indicate that PGE2 and other synthetic prostanoids reduce noradrenaline release from cardiac adrenergic nerve terminals acting on prejunctional inhibitory receptors belonging to the EP3 subtype.