Coherent high- and low-latitude climate variability during the holocene warm period

A faunal record of sea-surface temperature (SST) variations off West Africa documents a series of abrupt, millennial-scale cooling events, which punctuated the Holocene warm period. These events evidently resulted from increased southward advection of cooler temperate or subpolar waters to this subtropical location or from enhanced regional upwelling. The most recent of these events was the Little Ice Age, which occurred between 1300 to 1850 A.D., when subtropical SSTs were reduced by 3 degrees to 4 degrees C. These events were synchronous with Holocene changes in subpolar North Atlantic SSTs, documenting a strong, in-phase link between millennial-scale variations in high- and low-latitude climate during the Holocene.

Molecular basis of NMDA receptor-coupled ion channel modulation by S-nitrosylation

Several ion channels are thought to be directly modulated by nitric oxide (NO), but the molecular basis of this regulation is unclear. Here we show that the NMDA receptor (NMDAR)-associated ion channel was modulated not only by exogenous NO but also by endogenous NO. Site-directed mutagenesis identified a critical cysteine residue (Cys 399) on the NR2A subunit whose S-nitrosylation (NO+ transfer) under physiological conditions underlies this modulation. In cell systems expressing NMDARs with mutant NR2A subunits in which this single cysteine was replaced by an alanine, the effect of endogenous NO was lost. Thus endogenous S-nitrosylation can regulate ion channel activity.

Endoscopic ligation compared with combined treatment with nadolol and isosorbide mononitrate to prevent recurrent variceal bleeding

BACKGROUND

After an episode of acute bleeding from esophageal varices, patients are at high risk for recurrent bleeding and death. We compared two treatments to prevent recurrent bleeding--endoscopic ligation and combined medical therapy with nadolol and isosorbide mononitrate.

METHODS

We randomly assigned 144 patients with cirrhosis who were hospitalized with esophageal variceal bleeding to receive treatment with endoscopic ligation (72 patients) or the combined medical therapy (72 patients). Sessions of ligation were repeated every two to three weeks until the varices were eradicated. The initial dose of nadolol was 80 mg orally once daily, with adjustment according to the resting heart rate; isosorbide mononitrate was given in increasing doses, beginning at 20 mg once a day at bed time and rising over the course of one week to 40 mg orally twice a day, unless side effects occurred. The primary end points were recurrent bleeding, complications, and death.

RESULTS

The median follow-up period was 21 months. A total of 35 patients in the ligation group and 24 in the medication group had recurrent bleeding. The probability of recurrence was lower in the medication group, both for all episodes related to portal hypertension (P=0.04) and for recurrent variceal bleeding (P=0.04). There were major complications in nine patients treated with ligation (seven had bleeding esophageal ulcers and two had aspiration pneumonia) and two treated with medication (both had bradycardia and dyspnea) (P=0.05). Thirty patients in the ligation group died, as did 23 patients in the medication group (P=0.52). The probability of recurrent bleeding was lower for patients with a hemodynamic response to therapy, defined as a decrease in the hepatic venous pressure gradient of more than 20 percent from the base-line value or to less than 12 mm Hg (18 percent, vs. 54 percent in patients with no hemodynamic response at one year; P<0.001), and the probability of survival was higher (94 percent vs. 78 percent at one year, P=0.02).

CONCLUSIONS

Combined therapy with nadolol and isosorbide mononitrate is more effective than endoscopic ligation for the prevention of recurrent bleeding and is associated with a lower rate of major complications. A hemodynamic response to treatment is associated with a better long-term prognosis.

A putative protein complex consisting of Ctf19, Mcm21, and Okp1 represents a missing link in the budding yeast kinetochore

We have established a one-hybrid screen that allows the in vivo localization of proteins at a functional Saccharomyces cerevisiae centromere. Applying this screen we have identified three proteins-Ctf19, Mcm21, and the product of an unspecified open reading frame that we named Okp1-as components of the budding yeast centromere. Ctf19, Mcm21, and Okp1 most likely form a protein complex that links CBF3, a protein complex directly associated with the CDE III element of the centromere DNA, with further components of the budding yeast centromere, Cbf1, Mif2, and Cse4. We demonstrate that the CDE III element is essential and sufficient to localize the established protein network to the centromere and propose that the interaction of the CDE II element with the CDE III localized protein complex facilitates a protein-DNA conformation that evokes the active centromere.

Biochemical actions of chronic ethanol exposure in the mesolimbic dopamine system

In previous studies, we have demonstrated that chronic administration of morphine or cocaine produces some common biochemical adaptations in the ventral tegmental area (VTA) and nucleus accumbens (NAc), components of the mesolimbic dopamine system implicated in the reinforcing actions of these and other drugs of abuse. Since this neural pathway is also implicated in the reinforcing actions of ethanol, it was of interest to determine whether chronic ethanol exposure results in similar biochemical adaptations. Indeed, as seen for chronic morphine and cocaine treatments, we show here that chronic ethanol treatment increased levels of tyrosine hydroxylase and glial fibrillary acidic protein immunoreactivity, and decreases levels of neurofilament protein immunoreactivity, in the VTA. Also like morphine and cocaine, ethanol increases levels of cyclic AMP-dependent protein kinase activity in the NAc. These actions of ethanol required long-term exposure to the drug, and were in most cases not seen in the substantia nigra or caudateputamen, components of the nigrostriatal dopamine system studied for comparison. Altered levels of tyrosine hydroxylase in catecholaminergic cells frequently reflect altered states of activation of the cells. Moreover, increasing evidence indicates that ethanol produces many of its acute effects on the brain by regulating NMDA glutamate and GABAA receptors. We therefore examined the influence of chronic ethanol treatment on levels of expression of specific glutamate and GABA receptor subunits in the VTA. It was found that long-term, but not short-term, ethanol exposure increased levels of immunoreactivity of the NMDAR1 subunit, an obligatory component of NMDA glutamate receptors, and of the GluR1 subunit, a component of many AMPA glutamate receptors; but at the same time, long-term ethanol exposure decreased immunoreactivity levels of the alpha 1 subunit of the GABAA receptor complex. These changes are consistent with an increased state of activation of VTA neurons inferred from the observed increase in tyrosine hydroxylase (TH) expression. These results demonstrate that chronic ethanol exposure results in several biochemical adaptations in the mesolimbic dopamine system, which may underlie prominent changes in the structural and functional properties of this neural pathway related to alcohol abuse and alcoholism.

Continuous versus inpatient prophylaxis of the first episode of spontaneous bacterial peritonitis with norfloxacin

Cirrhotic patients with ascites and low ascitic fluid total protein and/or high serum bilirubin levels are at high risk to develop the first episode of spontaneous bacterial peritonitis during long-term follow-up. The aim of the present study was to determine the efficacy of continuous long-term selective intestinal decontamination with norfloxacin in the prevention of this complication. One hundred nine cirrhotic patients with ascites and ascitic fluid total protein levels of < or = 1 g/dL or serum bilirubin levels of > 2.5 mg/dL without previous spontaneous bacterial peritonitis were prospectively randomized into two groups: group 1 (n = 56) received norfloxacin, 400 mg daily administered orally, and group 2 (n = 53) was the long-term control group, receiving norfloxacin only during hospitalization. During a mean follow-up of 43 +/- 3 weeks, there was one spontaneous bacterial peritonitis (1.8%) in group 1 and 9 (16.9%) in group 2 (P < .01). The incidence of community-acquired spontaneous bacterial peritonitis was lower in group 1 (1.8% vs. 13.2%, P < .05), whereas the incidence of nosocomial spontaneous bacterial peritonitis (0% vs. 3.7%) and the incidence of extraperitoneal infections (25% vs. 24.5%) were similar in both groups (P = NS). The actuarial probability of survival at 18 months was 75% in group 1 and 62% in group 2 (P = NS). Resistance to norfloxacin was observed in 9 of 10 (90%) Escherichia coli isolated in infections from group 1 and in 4 of 11 (36.3%) from group 2 (P < .05). The overall incidence of infections caused by norfloxacin-resistant bacteria was higher in group 1 (19.6% vs. 15%), but it did not reach statistical significance. Continuous long-term selective intestinal decontamination with norfloxacin is effective in preventing the first spontaneous bacterial peritonitis in cirrhotic patients at high risk. However, the emergence of infections caused by norfloxacin-resistant bacteria must be weighed carefully against the benefits of continuous long-term prophylaxis.

Biochemical adaptations in the mesolimbic dopamine system in response to repeated stress

We have demonstrated previously that chronic administration of morphine, cocaine, or ethanol produces some common biochemical adaptations in the ventral tegmental area (VTA) and nucleus accumbens (NAc), components of the mesolimbic dopamine system implicated in the reinforcing and locomotor activating properties of these drugs of abuse. Because this neural pathway is also regulated by stress, and because stress has been shown to influence an animal's behavioral responses to drugs of abuse, it was of interest to determine whether repeated exposure to stress results in similar biochemical adaptations. By use of immunoblot analysis, we show here that a course of chronic "unpredictable" stress, like chronic drug exposure, increased levels of immunoreactivity of tyrosine hydroxylase and glial fibrillary acidic protein and decreased levels of immunoreactivity of neurofilament proteins in the VTA. Chronic unpredictable stress also increased levels of cyclic AMP-dependent protein kinase activity and decreased levels of immunoreactivity of the G protein subunit, Gi alpha, in the NAc. These effects required long-term exposure to stress and were in most cases not seen in the substantia nigra and caudate-putamen, components of the nigrostriatal dopamine system studied for comparison. The biochemical effects of chronic stress in the VTA and NAc differed among three strains of rat studied. Fischer 344 rats were the most responsive in that they exhibited all of the aforementioned adaptations, whereas Lewis rats were the least responsive in that they exhibited none of these adaptations; Sprague-Dawley rats exhibited an intermediate number of responses. Taken together, the results of the present study demonstrate that chronic exposure to stress results in biochemical adaptations in the mesolimbic dopamine system that resemble the chronic actions of several drugs of abuse. These adaptations could contribute to the convergent behavioral effects induced by treatments that are mediated via the VTA-NAc pathway.

Mapping the conversion of atrial flutter to atrial fibrillation and atrial fibrillation to atrial flutter. Insights into mechanisms

It is not generally believed that there is a relation between atrial flutter, thought to be due to a single reentrant circuit, and atrial fibrillation, thought to be due to simultaneously circulating multiple-reentrant wave fronts. However, there are many reasons to suggest that these rhythms are more closely related than previously thought. To test the hypothesis that the length of an area of functional block in the right atrial free wall is critical to the conversion of atrial flutter to atrial fibrillation and of atrial fibrillation to atrial flutter, we studied spontaneous and ATP-induced conversion of stable atrial flutter to sustained atrial fibrillation and spontaneous conversion of sustained atrial fibrillation to stable atrial flutter. We studied 13 episodes of the conversion of stable atrial flutter to sustained atrial fibrillation and sustained atrial fibrillation to stable atrial flutter in seven dogs with sterile pericarditis. Six episodes were spontaneous and seven were ATP related. All episodes were studied by using a multisite mapping system to record 190 unipolar electrograms (converted in the software to 95 bipolar electrograms) from the right atrial free wall along with ECG lead II. Atrial flutter induction was attempted by atrial stimulation (S1S2 or S1S2S3) or by rapid atrial pacing for > or = 20 beats from selected sites at selected rates. For both the spontaneous and the ATP-related episodes, stable atrial flutter was defined as any episode of > or = 5 minutes, and sustained atrial fibrillation was any episode of > or = 1 minute. During all the episodes of stable atrial flutter, a line of functional block with a mean length of 24 +/- 4 mm was localized on the right atrial free wall. When the previously stable line of functional block decreased to a mean of 16 +/- 3 mm (P < .05), either spontaneously or after ATP administration (40 mg i.v.), the new line of functional block was not long enough to maintain stable atrial flutter, and conversion to atrial fibrillation resulted. This shortened line of functional block continued to change and migrate over the right atrial free wall throughout sustained atrial fibrillation. These observations were similar for both spontaneous and ATP-induced conversions. When sustained atrial fibrillation evolved to stable atrial flutter, there was reformation of a long line of functional block, long enough (> or = prior length) to create a stable reentrant circuit, which then captured the right atrial free wall and subsequently both atria.(ABSTRACT TRUNCATED AT 400 WORDS)

Risk of a first community-acquired spontaneous bacterial peritonitis in cirrhotics with low ascitic fluid protein levels

BACKGROUND & AIMS

Long-term primary antibiotic prophylaxis of spontaneous bacterial peritonitis has been suggested to be useful in cirrhotic patients with low ascitic fluid protein levels. However, it is unlikely that all such patients need prophylactic treatment. The aim of this study was to identify the group of cirrhotic patients with low ascitic fluid protein levels at high risk of developing a first episode of spontaneous bacterial peritonitis during outpatient follow-up.

METHODS

One hundred nine cirrhotic patients with low ascitic fluid protein levels and without previous episodes of spontaneous bacterial peritonitis were followed up in an outpatient clinic.

RESULTS

Twenty-eight patients developed a first spontaneous bacterial peritonitis episode. In the multivariate analysis, serum bilirubin level (>3.2 mg /dL) and platelet count (<98.000/mm(3)) independently correlated with the risk of developing the first spontaneous bacterial peritonitis (P < 0.01 and P < 0.05, respectively). According to the median relative risk coefficient, a low-risk group (relative risk <1.09) and a high-risk group (relative risk >1.09) were established. The probability of developing a first spontaneous bacterial peritonitis episode at 1-year follow-up was significantly higher in the high risk-group (low-risk group, 23.6%; high-risk group, 55%; P < 0.01) as a consequence of a higher probability of the first community-acquired episode (13.7% vs. 47.6%, respectively, P < 0.01). One-year probability of survival was significantly lower in the high-risk group (low-risk group, 57.6%; high-risk group, 38%, P < 0.05).

CONCLUSIONS

Cirrhotic patients with low ascitic fluid protein levels (</=1 g /dL) and high bilirubin level and/or low platelet count are at high risk of developing a first episode of spontaneous bacterial peritonitis during long-term follow-up.

Amoxicillin-clavulanic acid versus cefotaxime in the therapy of bacterial infections in cirrhotic patients

BACKGROUND/AIM

Cefotaxime is considered the first-choice antibiotic for empirical treatment in cirrhotic patients developing bacterial infections. It has been suggested that amoxicillin-clavulanic acid could be an alternative to cefotaxime, particularly in patients developing bacterial infections while on prophylactic norfloxacin. The aim of the present study was to compare amoxicillin-clavulanic acid with cefotaxime in the treatment of bacterial infections in cirrhosis.

METHODS

Ninety-six hospitalized cirrhotic patients with suspicion of bacterial infection were prospectively included and randomized into two groups: one group (n=48) received amoxicillin-clavulanic acid, first intravenously 1 g-0.2 g every 8 h, and then orally 500 mg-125 mg every 8 h, and the other group (n=48) received intravenous cefotaxime 1 g every 6 h. Patients were stratified for previous prophylaxis with norfloxacin and ascitic fluid infection.

RESULTS

Sixteen patients were excluded from the analysis because bacterial infection was not demonstrated or because of secondary peritonitis. Therefore, 38 patients from the amoxicillin-clavulanic acid group and 42 from the cefotaxime group were finally analyzed. There were 24 ascitic fluid infections in each group. Infection resolution (86.8% vs 88%, 95% CI: -0.15 to 0.13, p NS), spontaneous bacterial peritonitis resolution (87.5% vs 83.3%, 95% CI: -0.15 to 0.24, p NS), duration of treatment, incidence of complications, time of hospitalization and hospital mortality were similar in both groups. Considering patients on prophylactic norfloxacin, infection resolution was also similar (100% vs 83.3%, 95% CI: -0.04 to 0.37, p NS). No adverse events were observed in either of the two groups. The cost of antibiotics was statistically lower in the amoxicillin-clavulanic acid group (p<0.001).

CONCLUSIONS

Amoxicillin-clavulanic acid is as effective as cefotaxime in the treatment of bacterial infections in cirrhotic patients, but is less expensive and can be administered orally. These results suggest that amoxicillin-clavulanic acid is an effective alternative to cefotaxime for the empirical treatment of bacterial infections in cirrhosis.

Somatostatin treatment and risk stratification by continuous portal pressure monitoring during acute variceal bleeding

BACKGROUND AND AIMS

During acute variceal bleeding, several factors may lead to elevations of hepatic venous pressure gradient (HVPG), which may precipitate further hemorrhage. Whether somatostatin can suppress these increments is unknown. This study monitored somatostatin effects on HVPG during acute bleeding and assessed whether the changes affect outcome.

METHODS

In 40 patients with acute variceal bleeding treated with sclerotherapy, a catheter was placed into a main hepatic vein for 24-hour serial measurements of HVPG. After baseline measurements, patients received somatostatin (N = 25) or placebo (N = 15) under double blind conditions.

RESULTS

Somatostatin but not placebo produced a sustained decrease in HVPG (from 20.7 +/- 3.7 mm Hg to 17.7 +/- 2.7, P < 0.01). In patients receiving placebo, HVPG increased after a test meal (P = 0.018) and after blood transfusion (P = 0.034). Somatostatin completely prevented these increments. HVPG decreased significantly only in patients without further bleeding. One of 27 patients with HVPG <20 mm Hg at baseline or decreased >10% rebled vs. 9 of 13 who had neither of these 2 criteria (P < 0.0001). Both criteria had independent prognostic value for further bleeding.

CONCLUSIONS

During acute variceal bleeding, somatostatin produces a significant and sustained decrease in HVPG and prevents secondary elevations. Monitoring HVPG may stratify further bleeding risk and discriminate treatment response.

Infections caused by Escherichia coli resistant to norfloxacin in hospitalized cirrhotic patients

Selective intestinal decontamination with norfloxacin is useful to prevent bacterial infections in several groups of cirrhotic patients at high risk of infection. However, the emergence of infections caused by Escherichia coli resistant to quinolones has recently been observed in cirrhotic patients undergoing prophylactic norfloxacin. Our aim is to determine the characteristics of the infections caused by E. coli resistant to norfloxacin in hospitalized cirrhotic patients. One hundred and six infections caused by E. coli in 99 hospitalized cirrhotic patients were analyzed and distributed into two groups: group I (n = 67), infections caused by E. coli sensitive to norfloxacin, and group II (n = 39), infections caused by E. coli resistant to norfloxacin. The clinical and analytical characteristics at diagnosis of the infection were similar in both groups. Previous prophylaxis with norfloxacin was more frequent in group II (15/67, 22.4% vs. 32/39, 82%, P <.0001), as a result of a higher number of patients submitted to continuous long-term prophylaxis in this group, whereas previous short-term prophylaxis was similar in both groups. Infections were more frequently nosocomial-acquired in group II than in group I (17/67, 25.3% vs. 20/39, 51.2%, P =.01). The type of infections was similar in both groups: urinary tract infections 38 in group I and 24 in group II, spontaneous bacterial peritonitis 8 and 2, spontaneous bacteremia 4 and 4, and bacterascites 1 and 0, respectively (pNS). Mortality during hospitalization was similar in the two groups (4/67, 5.9% vs. 5/39, 12.8%, pNS). None of the E. coli resistant to norfloxacin were also resistant to cefotaxime and only one of them was resistant to amoxicillin-clavulanic acid. Prophylaxis with norfloxacin, usually continuous long-term prophylaxis, favors the development of infections caused by norfloxacin-resistant E. coli. Long-term antibiotic prophylaxis should therefore be restricted to highly selected groups of cirrhotic patients at high-risk of infection. Infections caused by E. coli resistant to norfloxacin show a severity similar to those caused by sensitive E. coli. No significant associated resistance between norfloxacin and the antibiotics most frequently used in the treatment of bacterial infections in cirrhotic patients has been observed.

Serotonergic status in human blood

Preliminary data on the existence of a plasma pool of serotonin (5HT) in human blood has been confirmed in a descriptive study of two distinctive pools of 5HT (plasma and platelet), and its metabolite 5-hydroxyindoleacetic acid (5HIAA), in the blood of 175 healthy individuals. Plasma 5HT (0.93 +/- 0.67 ng/mL, X +/- S.D.) shows a significant but low correlation with platelet 5HT (711 +/- 319 ng/10(9) platelets) (r=0.29, p less than 0.001). Diastolic blood pressure correlated significantly with plasma 5HT (r=0.51, p less than 0.05) and whole blood 5HT (r=0.52, p less than 0.05) in older individuals (50-65 years) but not in the whole group (r=0.052, n.s.). Differences between sexes include plasma 5HT, whole blood 5HT (both higher in women) and plasma 5HIAA (lower in women) and may reflect a differential whole body 5HT function. The effect of meal consumption and a peripheral 5HT synthesis inhibitor (carbidopa) in four human subjects has also been tested. Carbidopa (0.7 mg/kg) significantly lowers the plasma pool of 5HT (mean change -33%) 2 hr. after administration, while platelet 5HT is unchanged. These data support the existence of a human plasma 5HT pool, with a rapid turnover, different from the 5HT in platelets (slow turnover, reserve pool). Both may be useful in evaluating different aspects of 5HT-mediated pathologies.

Strain-selective effects of corticosterone on locomotor sensitization to cocaine and on levels of tyrosine hydroxylase and glucocorticoid receptor in the ventral tegmental area

We have studied biochemical and behavioral effects of chronic corticosterone administration in two inbred rat stains (Fischer 344 and Lewis), known to differ in their hypothalamic-pituitary-adrenal axis and in their behavioral responses to drugs of abuse. First, we studied corticosterone regulation of phosphoproteins in the ventral tegmental area of sham- and corticosterone-treated Fischer and Lewis rats, by means of back-phosphorylation and two-dimensional gel electrophoresis and Western blotting analysis. Corticosterone administration upregulated tyrosine hydroxylase immunoreactivity and decreased glial-fibrillary acidic protein phosphorylation state in the ventral tegmental area of Fischer rats only, with no changes seen in Lewis rats. We also studied corticosterone effects on locomotor sensitization to cocaine, a behavior known to be regulated by the ventral tegmental area. In Fischer rats, chronic corticosterone pretreatment resulted in development of cocaine sensitization, which was absent in sham-pretreated Fischer rats. In contrast, Lewis rats developed cocaine sensitization either with or without corticosterone pretreatment. Thus, both biochemical and behavioral effects of corticosterone observed in Fischer rats were absent in Lewis rats. We next studied the possibility that certain transcription factors, thought to play a role in tyrosine hydroxylase expression, could be involved in these strain-selective effects of corticosterone. Corticosterone treatment decreased levels of glucocorticoid receptor immunoreactivity in the ventral tegmental area of Lewis rats, but not of Fischer rats. In addition, drug-naive Fischer rats showed higher ventral tegmental area levels of immunoreactivity of cyclic AMP response element binding protein than Lewis rats, with no effect of corticosterone observed in either strain. These findings suggest that hypothalamic-pituitary-adrenal axis modulation of responses to drugs of abuse is a genetically determined characteristic seen in Fischer rats, but absent in Lewis rats. We propose that corticosterone administration down-regulates the glucocorticoid receptor in the ventral tegmental area of Lewis rats, and thereby prevents other adaptations to corticosterone treatment, while in the ventral tegmental area of Fischer rats the lack of glucocorticoid receptor down-regulation and the high basal levels of cyclic AMP response element binding protein could facilitate the transcriptional, biochemical and behavioral actions of glucocorticoids.

Chronic morphine administration increases beta-adrenergic receptor kinase (beta ARK) levels in the rat locus coeruleus

Based on the established role of beta-adrenergic receptor kinase (beta ARK) and beta-arrestin in the desensitization of several G protein-coupled receptors, we investigated the effect of chronic morphine administration on beta ARK and beta-arrestin levels in selected brain areas. Levels of beta ARK were measured by blot immunolabeling analysis using antibodies specific for two known forms of beta ARK, i.e., beta ARK1 and beta ARK2. It was found that chronic morphine treatment produced an approximately 35% increase in levels of beta ARK1 immunoreactivity in the locus coeruleus, but not in several other brain regions studied. In contrast, chronic morphine treatment failed to alter levels of beta ARK2 immunoreactivity in any of the brain regions studied. Levels of beta-arrestin immunoreactivity, measured using an antiserum that recognizes two major forms of this protein in brain, were also found to increase (by approximately 20%) in the locus coeruleus. It is proposed that chronic morphine regulation of beta ARK1 and beta-arrestin levels may contribute to opioid-receptor tolerance that is known to occur in this brain region.

Somatostatin alone or combined with emergency sclerotherapy in the treatment of acute esophageal variceal bleeding: a prospective randomized trial

Recent trials have shown that somatostatin (SMT) is as effective as sclerotherapy in the treatment of acute variceal bleeding and that the combination of both treatments is more effective than sclerotherapy alone. To assess whether the addition of sclerotherapy improves the efficacy of SMT alone, all patients admitted to our unit with gastrointestinal bleeding and with suspected cirrhosis received a continuous infusion of SMT (250 micrograms/h). Endoscopy was performed between 1 and 5 hours later, and patients with esophageal variceal bleeding were randomized to receive or not to receive sclerotherapy. In both groups, SMT infusion was continued for 5 days. Fifty patient admissions were allocated to each group. Therapeutic failure occurred in 21 cases of the SMT group and in 7 cases of the combined-therapy group (P =.002). Failure to control the acute episode occurred in 24% vs. 8% (P =.03) and early rebleeding in 24% vs. 7% (P =.03), respectively. Transfusional requirements were significantly higher in the SMT group, while the incidence of complications was lower (8% vs. 24%; P =.029). In the multivariate analysis, the presence of shock at admission and active bleeding during endoscopy were the variables that better predicted the failure of therapy with SMT alone. Mortality at 6 weeks was similar. These data demonstrate that the addition of sclerotherapy significantly improves the efficacy of SMT alone for the treatment of acute variceal bleeding, although it also increases the rate of complications. Patients with shock and those with active bleeding are more likely to benefit from this combined therapy.

Hepatitis C virus reinfection among prisoners with sustained virological response after treatment for chronic hepatitis C

BACKGROUND & AIMS

We estimated HCV reinfection rate and its associated risk factors in inmates with chronic hepatitis C who had achieved sustained virological response (SVR) after completing combination therapy while in prison.

METHODS

Individuals who had achieved an SVR after treatment provided from January 2003 to December 2009 at four prisons in Catalonia, had been tested annually for HCV RNA and were in prison during 2010, were invited to complete a questionnaire regarding risk factors for reinfection. Incidence rate was calculated as 100 person-years of follow-up. Risk factors potentially associated with reinfection were evaluated by bivariate log-rank test and multivariate Cox regression analysis.

RESULTS

One hundred and nineteen subjects who had achieved an SVR agreed to participate. 98% were male, with a median age of 33.3 ± 6.3 years and 81% had a history of injection drug use (IDU). After a mean follow-up of 1.4 years, HCV reinfection was identified in nine former IDUs, seven with HCV genotype switch, for an overall reinfection rate of 5.27 cases per 100 person-years. Reinfection incidence was significantly higher among active drug users (HR=12.47; 95% CI: 2.90-53.71), HIV co-infected (HR=9.95; 95% CI: 1.73-57.34), and those engaging in more than one risk behaviors after treatment (HR=7.47; 95% CI: 1.19-46.89).

CONCLUSIONS

HCV reinfection among inmates after successful treatment is high especially in those with ongoing IDU. Preventative interventions at diagnosis and during and after HCV treatment should be strongly reinforced.

Randomized trial comparing three forms of pelvic floor repair for neuropathic faecal incontinence

A randomized controlled trial in women with neuropathic faecal incontinence compared total pelvic floor repair (n = 12) with anterior levatorplasty and sphincter plication alone (n = 12) and postanal repair alone (n = 12). Review at 6 and 24 months indicated that results were significantly better for total pelvic floor repair than either of the other procedures. Complete continence was achieved in eight of the 12 patients 2 years after total pelvic floor repair. Only total repair significantly elongated the anal canal. Both total pelvic floor repair and anterior levatorplasty improved sensation in the upper anal canal.

Effects of monoamine uptake inhibitors on extracellular and platelet 5-hydroxytryptamine in rat blood: different effects of clomipramine and fluoxetine

1. The concentration of 5-hydroxytryptamine (5-HT) in rat platelet-free plasma increased significantly 30 min after a single i.p. injection (10 mg kg-1) of each of six inhibitors of the high-affinity 5-HT uptake (fluvoxamine, fluoxetine, alaproclate, paroxetine, sertraline and clomipramine). The increases ranged from 226% to 776% of control values. In contrast, imipramine, desipramine and femoxetine had no significant effect. The increase elicited by paroxetine was dependent on the dose (1, 5 and 10 mg kg-1) and returned to control values after 4 h. That observed after clomipramine was also transient and paralleled the plasma concentration of the drug (Spearman-rank correlation r = 0.43). 2. In vivo, the rat pulmonary vascular endothelium removed trace amounts (8.8 nmol in a bolus) of intravenously injected [14C]-5-HT. Paroxetine pretreatment (10 mg kg-1, 30 min before-hand) reduced this uptake by 73%. 3. Repeated fluoxetine treatments reduced rat whole blood 5-HT concentration (ca. -60% after daily 2 x 5 mg kg-1, i.p. during 14 days). However, plasma (extracellular) 5-HT was not increased. 4. Various repeated treatments with clomipramine (i.p. injections or osmotic minipumps, up to 30 mg kg-1 day-1), failed to decrease rat whole blood 5-HT concentrations. Platelet-free plasma 5-HT was also unchanged, even after treatments yielding plasma clomipramine levels 2.7 times higher than those that increased it acutely. 5. These results indicate that the extracellular pool of 5-HT in rat blood (measured in the platelet-free plasma) is physiologically under the control of high-affinity 5-HT uptake systems.The sustained 5-HT uptake inhibition does not result in an increase of 5-HT in platelet-free plasma, suggesting that adaptative mechanisms are triggered. The distinct long-term effects of the two antidepressants clomipramine and fluoxetine on rat whole blood 5-HT suggest a differential in vivo action on the rat 5-HT uptake.

Assay method for the carboxylic acid metabolite of clopidogrel in human plasma by gas chromatography-mass spectrometry

This paper describes a GC-MS method for the analysis of the carboxylic acid metabolite (SR26334, II) of methyl (+)-(S)-alpha-(o-chlorophenyl)-6,7-dihydrothieno[3,2-c]pyridine-5( 4H)-acetate hydrogensulfate (clopidogrel, SR 25990, I) in plasma and serum. The analytical procedure involves a robotic liquid-liquid extraction with diethyl ether followed by a solid-liquid extraction on C18 cartridges. The derivatization process was performed using n-ethyl diisopropylethylamine and alpha-bromo-2,3,4,5,6-pentafluoro toluene. A structural analogue (III) of II, was used as internal standard. The 1/X2; weighted calibration curve obtained in the range 5-250 ng/ml was well described by a quadratic equation. The extraction efficiency was better than 48% over the range studied; for the internal standard it averaged 51% at 50 ng/ml. Precision ranged from 3.6 to 15.8%, and accuracy was between 92 and 114%. Dilution has no influence on the performance of the method which could then be used to quantitate plasma samples containing up to 25000 ng/ml. The limit of quantification was 5 ng/ml. The method validation results indicate that the performance characteristics of the method fulfilled the requirements for assay methods for use in pharmacokinetic studies.

Isolated pulmonic valve infective endocarditis: a persistent challenge

Isolated pulmonic valve infective endocarditis is an uncommon clinical entity. We report our experience with three patients diagnosed with pulmonic valve endocarditis from our institution. Two cases were caused by Enterococcus faecalis (one was resistant to vancomycin) and one by coagulase-negative staphylococci (CNS). One of the cases of isolated pulmonic valve endocarditis due to the E. faecalis was nosocomially acquired; the case of CNS pulmonic valve endocarditis was dialysis catheter related. Each patient with isolated pulmonic valve endocarditis presented with hypotension and interstitial pulmonary infiltrates. Two patients were treated with linezolid. Both vancomycin-resistant enterococci (VRE) and CNS were eliminated from blood cultures on linezolid therapy. The challenges inherent in the management of pulmonic valve endocarditis mandate the development of individual patient-specific guidelines.

Correlation Between Mast Cell Density and Myocardial Fibrosis in Congestive Heart Failure Patients

Besides the well-established role of mast cells in allergic reactions as an important source of vasoactive and proinflammatory products, they have been related to tissue fibrosis and remodelling processes. In a heart failure (HF) animal model, mast cells were shown to synthesize transforming growth factor beta1 and basic fibroblast growth factor in myocardial tissue and were localized to an area with fibrosis. Our objective was to quantify mast cell density in left ventricles from patients with congestive heart failure who were candidates for transplantation and to analyze whether they showed a correlation with the fibrosis level of the same area.

METHODS

We obtained myocardial biopsies from 20 patients with end-stage HF secondary to idiopathic dilated cardiomyopathy (iDCM) undergoing heart transplantation and 15 controls (donors without cardiopathy). Mast cells were detected by immunohistochemistry with a human mast cell chymase antibody and fibrosis levels measured with picrosirius red staining of collagen fibrils with later quantification by morphometry.

RESULTS

The patients mean age was 51 +/- 3 years. Fibrosis levels in the myocardial sections from patients with congestive HF was three-fold higher than those in control myocardium (12.41 +/- 1.7% vs 3.98 +/- 0.63%, P < .001). Mast cell density correlated with the collagen fraction and could be fitted to a linear regression curve: collagen fraction = 0.78 + 0.05 mast cell density (n = 33, P < .005, R2 = 0.28).

CONCLUSION

The elevated collagen fraction present in failing hearts may be the cause of increased stiffness and loss of elasticity that is detected in patients with end-stage HF. Due to the mast cells capacity to synthesize vasoactive and fibrogenic products and the correlation between their density and fibrosis levels, they probably play a role in the ventricular remodelling in HF.

Epidemiological and genetic studies suggest a common Leishmania infantum transmission cycle in wildlife, dogs and humans associated to vector abundance in Southeast Spain

Leishmania infantum infection was investigated in 202 wild carnivores, rodents and lagomorphs in Southeast Spain using a real-time PCR (rtPCR) in skin and organ samples, mostly spleen. Lesions compatible with leishmaniosis were not observed in any of the animals. Prevalence defined as the percentage of rtPCR-positive animals was 32% overall, and 45% in foxes (n = 69), 30% in rabbits (n = 80) and stone martens (n = 10), 19% in wood mice (n = 16), 0% in black rats (n = 10) and ranged between 0% and 100% in other minoritarian species including badgers, wild cats, wolves, raccoons, genets and hares. Most infected rabbits were rtPCR-positive in skin and not in spleen samples and the opposite was the case for foxes (p < 0.05). L. infantum prevalence was lowest in spring following months of non-exposure to phlebotomine sand fly vectors, and spatially matched recently estimated Phlebotomus perniciosus vector abundance and the prevalence of subclinical infection in dogs and humans. Prevalence increased with altitude and was greater in drier and less windy South and West compared to the coastal Southeast of the study area (p < 0.05). Genetic diversity of L. infantum from foxes, investigated by PCR-restriction fragment length polymorphisms of kinetoplast DNA, revealed B genotype in all animals, which is frequent in people and dogs in the Iberian Peninsula and Morocco. The study provides further evidence that subclinical L. infantum infection is widespread in wildlife with prevalence depending on environmental factors and that parasite tissue tropism may vary according to host species. Moreover, it suggests that sylvatic and domestic transmission cycles are closely interconnected.

One-year mortality prognosis in heart failure: a neural network approach based on echocardiographic data

OBJECTIVES

This study sought to assess the usefulness and accuracy of artificial neural networks in the prognosis of 1-year mortality in patients with heart failure.

BACKGROUND

Artificial neural networks is a computational technique used to represent and process information by means of networks of interconnected processing elements, similar to neurons. They have found applications in medical decision support systems, particularly in prognosis.

METHODS

Clinical and Doppler-derived echocardiographic data from 95 consecutive patients with diffuse impairment of myocardial contractility were studied. After 1 year, data regarding survival or death were obtained and produced the prognostic variable. The data base was divided randomly into a training data set (47 cases, 8 deaths) and a testing data set (48 cases, 7 deaths). Results of artificial neural network classification were compared with those from linear discriminant analysis, clinical judgment and conventional heuristically based programs.

RESULTS

The study group included 57 male (47 survivors) and 38 female patients (33 survivors). Linear discriminant analysis was not efficient for separating survivors from nonsurvivors because the accuracy at the ideal cutoff value was only 67.4%, with a sensitivity of 67.5%, positive predictive value of 27.8% and negative predictive value of 91.5%. In contrast, all artificial neural networks were able to predict outcome with an accuracy of 90%, specificity of 93% and sensitivity of 71.4%, for the best artificial neural network. Both clinical judgment and automatic heuristic methods were also inferior in performance.

CONCLUSIONS

The artificial neural network method has proved to be reliable for implementing quantitative prognosis of mortality in patients with heart failure. Additional studies with larger numbers of patients are required to better assess the usefulness of artificial neural networks.

Interaction of environmental moisture with powdered green tea formulations: effect on catechin chemical stability

Green tea and tea catechins must be stable in finished products to deliver health benefits; however, they may be adversely affected by tea processing/storage conditions and the presence of other components. The objective of this study was to determine the effects of storage relative humidity (RH) and addition of other ingredients on catechin stability in simulated dry beverage mixtures. Samples of green tea powder alone and mixed with sucrose, citric acid, and/or ascorbic acid were prepared and stored in desiccators at 22 degrees C and 0-85% RH for up to 3 months. Epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate were determined by high-performance liquid chromatography (HPLC). Formulation and the interaction of formulation and RH significantly promoted catechin degradation ( P < 0.0001). The chemical degradation of total and individual catechins in green tea powder formulations was significantly increased ( P < 0.0001) by exposure to increasing RH, and the degradation was exacerbated at > or = 58% RH by the presence of powdered citric acid and at > or = 75% RH by the presence of ascorbic acid. Catechins degraded the most in formulations containing both acids. Although catechin chemical stability was maintained at < or = 43% RH in all samples stored at 22 degrees C for 3 months, caking was observed in samples at these relative humidities. These results are the first to demonstrate that addition of other dry components to tea powders may affect catechin stability in finished dry blends and highlight the importance of considering the complex interplay between a multicomponent system and its environment for developing stable products.