Clinical Significance of Clostridium difficile in Children Less Than 2 Years Old: A Case-Control Study.

BACKGROUND: The significance of Clostridium difficile (CD) in the stools of children 2 years old or younger remains unclear. The aim of this study was to investigate risk factors and clinical evolution of diarrheic children ≤2 years old with or without CD in their stools. METHODS: From January 1, 2012 to December 31, 2013, all diarrheic stool samples received in our laboratory were screened for CD. We randomly selected diarrheic children ≤2 years old (n = 100) with an isolation of toxigenic CD in the stools and compared them with diarrheic children (n = 100) without isolation of CD. RESULTS: Cases and controls were appropriately matched for age and sex. We found no significant differences between children with or without CD. Of the CD cases, we compared the patients receiving treatment with metronidazole (19%) versus those that were not prescribed treatment (81%), and found that patients in the first group had used more gastric acid suppressants (P = 0.02), had surgery in the last month (P = 0.03) and also presented with more days with diarrhea (P = 0.03). All the patients, including CD cases, independently of the administration of metronidazole, were cured of the diarrheic episode. Polymerase chain reaction-ribotyping performed in all CD cases showed that the most prevalent ribotype was 014 (25%). CONCLUSIONS: Our study reinforces the nonsignificance of CD in neonates and infants younger than 2 years old. Informing clinicians of CD isolates in this population promotes the use of antibiotics against CD, without evidence of a different outcome than those not receiving treatment.

Persistent Infection by a Mycobacterium tuberculosis Strain That Was Theorized To Have Advantageous Properties, as It Was Responsible for a Massive Outbreak.

The strains involved in tuberculosis outbreaks are considered highly virulent and transmissible. We analyzed the case of a patient in Madrid, Spain, who was persistently infected over an 8-year period by the same Beijing Mycobacterium tuberculosis strain. The strain was responsible for a severe outbreak on Gran Canaria Island. The case provides us with a unique opportunity to challenge our assumptions about M. tuberculosis Beijing strains. No clinical/radiological findings consistent with a virulent strain were documented, and the in vitro growth rate of the strain in macrophages was only moderate. No secondary cases stemming from this prolonged active case were detected in the host population. The strain did not acquire resistance mutations, despite constant treatment interruptions, and it remained extremely stable, as demonstrated by the lack of single-nucleotide-polymorphism (SNP)-based differences between the sequential isolates. Our data suggest that the general assumption about M. tuberculosis Beijing strains having advantageous properties (in terms of virulence, transmissibility, and the tendency to acquire mutations and resistance) is not always accurate.

Improvement of capecitabine antitumoral activity by melatonin in pancreatic cancer.

OBJECTIVE: The purpose of our study was to evaluate the effects of the addition of melatonin and capecitabine on experimental pancreatic cancer. METHODS: Fifty Syrian hamsters were randomized in 5 groups: group 1: no tumor induction (control group); group 2: tumor induction with BOP [N-nitrosobis(2-oxopropyl) amine]; group 3: tumor induction with BOP and melatonin administration; group 4: tumor induction with BOP and capecitabine administration; and group 5: tumor induction with BOP and administration of combined capecitabine and melatonin therapy. The evaluation of pathological tumor evolution and oxidative stress markers in pancreatic tissue was carried out. RESULTS: All animals under BOP exposure presented poorly or moderately differentiated pancreatic adenocarcinoma associated with increased lipoperoxide levels and decreased antioxidant activity in pancreatic tissue. Pancreatic cancer was shown in only 66% of the capecitabine-treated group and 33% of melatonin-treated group (P < 0.05), most of them moderately differentiated adenocarcinoma. When capecitabine and melatonin were combined, a well-differentiated pancreatic adenocarcinoma was observed in 10% of animals. The beneficial effect was associated with a decrease in lipoperoxide levels and increased antioxidant activity in pancreatic tissue. CONCLUSIONS: The combined administration of capecitabine and melatonin provided an improvement in antioxidant status as well as a synergistic antitumoral effect in experimental pancreatic cancer.

Melatonin and celecoxib improve the outcomes in hamsters with experimental pancreatic cancer.

Pancreatic cancer is a major health problem because of the aggressiveness of the disease and the lack of effective systemic therapies. Melatonin (MEL) has antioxidant activity and prevents experimental genotoxicity. The specific inhibitor of cyclooxygenase-2 (COX-2), celecoxib (CEL), increases the efficacy of chemoradiotherapy in advanced pancreatic cancer. The objective of the study was the comparison and synergic effect of MEL and CEL during either the induction or progression phases of the tumor process, measuring parameters of oxidative stress, number of tumor nodules and survival of animals with pancreatic cancer. Pancreatic cancer was induced by N-nitrosobis (2-oxopropyl)amine) (BOP) in Syrian hamsters. Melatonin and/or CEL were administered during the induction, postinduction as well as during both phases. The presence of tumor nodules were observed macroscopically in pancreatic and splenic areas, and the levels of lipoperoxides (LPO), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in pancreatic tissue were measured. The increases in tumor nodules and LPO as well as the reductions in GSH and enzymatic antioxidants in the pancreas induced by BOP were related to a lower survival rate of animals. The administration of MEL exerted a more potent beneficial effect than CEL treatment on the reduction in tumor nodules, oxidative stress and death of experimental BOP-treated animals. The combined treatment only exerted a synergistic beneficial effect when administered during the induction phase. Melatonin by itself had significant beneficial actions in improving the survival of hamsters.

Antioxidant-like effects and protective action of transcranial magnetic stimulation in depression caused by olfactory bulbectomy.

We studied the effects of transcranial magnetic stimulation (TMS, 60 Hz and 0.7 mT for 4 h/day for 14 days) on oxidative and cell damage caused by olfactory bulbectomy (OBX) in Wistar rats. The levels of lipid peroxidation products and caspase-3 were enhanced by OBX, whereas it prompted a reduction in reduced glutathione (GSH) content and antioxidative enzymes activities. The treatment with TMS reverted towards normality the biomarkers indicative of oxidative stress and apoptosis. In conclusion, our data show that TMS induced a protection against cell and oxidative damage induced by OBX, as well as they support the hypothesis that oxidative stress may play an important role in depression.

Protective effect of nicotine on oxidative and cell damage in rats with depression induced by olfactory bulbectomy.

We evaluated the effects of nicotine on cell and oxidative damage caused by olfactory bulbectomy (OBX). The rats were divided into seven groups as follows: i) control; ii) vehicle (6% ethanol); iii) treated with nicotine; iv) sham operated; v) olfactory bulbectomy (OBX); vi) OBX+vehicle; and vii) OBX+Nic. The OBX was performed using the trepanation of frontal bone. The olfactory bulbs were cut and removed without damage to the frontal cortex. Two weeks after surgery nicotine was administered chronically once daily for 14 days, intraperitoneally (i.p.) in doses of 1.5 mg/kg, two weeks after surgery. OBX caused an increase in lipid peroxidation products and caspase-3 but prompted a reduction in reduced glutathione (GSH) content and antioxidative enzyme activity. All these changes were reverted by treatment of nicotine (14 days). In conclusions: i) OBX induces oxidative stress and cell death by apoptosis; and ii) nicotine presents antidepressant and antioxidant effect. All these findings suggest that nicotine would be a therapeutic tool for depression, although more studies are needed in this area to define the appropriate treatment regime.

Melatonin exerts a more potent effect than S-adenosyl-l-methionine against iron metabolism disturbances, oxidative stress and tissue injury induced by obstructive jaundice in rats.

Melatonin and S-adenosyl-l-methionine (SAMe) prevent oxidative stress and tissue dysfunction in obstructive jaundice (OJ). Lipid peroxidation is exacerbated in the presence of trace amounts of iron (Fe). The study investigated the regulation by melatonin and SAMe the induction of oxidative stress, iron metabolism disturbances and tissue injury in an experimental model of OJ. Different parameters of lipid peroxidation, antioxidant status, tissue injury and Fe metabolism were determined in liver and blood. OJ induced Fe accumulation in liver, and increased transferrin (Tf) saturation and loosely bound Fe content in blood. Melatonin, and SAMe at lesser extent, enhanced protein Tf content in liver and blood, that reduced loosely bound Fe content in blood. Melatonin and SAMe did not affect ferritin (FT) and Tf mRNA expression, but reduced Tf receptor (TfR) mRNA expression in liver. In conclusion, the effect of melatonin and SAMe on Fe metabolism may be included in the beneficial properties of these agents on lipid peroxidation and tissue injury induced by OJ.

Beneficial properties of melatonin in an experimental model of pancreatic cancer.

Pancreatic cancer is a major health problem because of the aggressiveness of the disease and the lack of effective systemic therapies. Melatonin has antioxidant activity and prevents experimental genotoxicity. However, the effect of melatonin in pancreatic cancer has not been tested. Pancreatic carcinogenesis was induced by N-nitrosobis (2-oxopropyl)amine (BOP) in Syrian hamsters. Melatonin was administered during the BOP-induction phase (12 wk) and/or following the postinduction phase (12 wk). Different parameters of oxidative stress including lipid peroxides (LPO) and antioxidants (superoxide dismutase, catalase, reduced glutathione and glutathione peroxidase) were determined in pancreatic tissue. Also, the presence of atypical hyperplasia (AH), well and moderately differentiated adenomacarcinoma (ADC-WD and ADC-MD, respectively) were studied. The administration of BOP induced an intense oxidative stress and ADC induction in the pancreas. The administration of melatonin during the induction or postinduction phase reduced LPO and improved the antioxidant status, as well as drastically reducing the presence of ADC but some AH remained. In conclusion, treatment with melatonin reduced oxidative damage and cancer nodules induced by BOP in the pancreas.

Melatonin prevents brain oxidative stress induced by obstructive jaundice in rats.

The aim of the study was to analyze the impact of melatonin on brain oxidative stress in experimental biliary obstruction. Cholestasis was done by a double ligature and section of the extrahepatic biliary duct. Melatonin was injected intraperitoneally (500 microg/kg/day). Malondialdehyde (MDA), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) contents were determined in the brain tissue. Biliary obstruction raised MDA and reduced GSH contents in the cortex, cerebellum, and hypothalamus areas. Moreover, the scavenger enzyme activity significantly dropped in all areas of the brain. Melatonin drastically reduced MDA concentration and enhanced GSH concentration, as well as all antioxidant enzyme activity in all brain areas obtained from the bile duct-ligated animals. In conclusion, the treatment with melatonin decreased lipid peroxidation and recovered the antioxidant status in the brain from cholestatic animals.

Comparison of melatonin, vitamin E and L-carnitine in the treatment of neuro- and hepatotoxicity induced by thioacetamide.

This study was designed to evaluate and compare the effect of melatonin, vitamin E and L-carnitine on brain and liver oxidative stress and liver damage. Oxidative stress and hepatic failure were produced by a single dose of thioacetamide (TAA) (150 mg kg(-1)) in Wistar rats. A dose of either melatonin (3 mg kg(-1)) vitamin E (20 mg kg(-1) ) or L-carnitine (100 mg kg(-1)) was used. Blood samples were taken from the neck vasculature in order to determine ammonium, blood urea nitrogen (BUN) and liver enzymes. Lipid peroxidation products, glutathione (GSH) content and antioxidative enzymes were determined in cerebral and hepatic homogenates. The results showed a decrease in BUN and in the antioxidant enzymes activities and GSH in the brain and liver. Likewise, TAA induced significant enhancement of lipid peroxidation products levels in both liver and brain, as well as in ammonia values. Melatonin, vitamin E and L-carnitine, although melatonin more significantly, decreased the intensity of the changes produced by the administration of TAA alone. Furthermore melatonin combined with TAA, decreased the ammonia levels and increased the BUN values compared with TAA animals. Also it was more effective than vitamin E or L-carnitine in these actions. These data show the protective effect of these agents, especially melatonin, against oxidative stress and hepatic damage present in fulminant hepatic failure.

Protective effect of carvedilol on oxidative stress induced by okadaic acid in N1E-115 cells.

The effect of carvedilol on oxidative and cell damage induced by okadaic acid in N1E-115 cells were studied. The effects of okadaic acid were evaluated as changes in: the quantity of lipid peroxidation products, protein carbonyl groups, reduced glutathione content (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase and total lactate dehydrogenase (cell LDH). Additionally, a dose of carvedilol (10(-5)M) was added 2h before incubation with okadaic acid (50 nM) and was present until the end of the experiment (2h later added okadaic acid). Our results reveal that okadaic acid induces oxidative stress and an increase of cell LDH in N1E-115 cells, whereas carvedilol prevented the changes prompted by okadaic acid. In conclusion, the data show the protective effect of carvedilol, as well as its ability to modify cell response to okadaic acid, involving like cytoprotective mechanism its antioxidative properties.

Role of serotonin in cerebral oxidative stress in rats.

Serotonin or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter synthesized by the aromatic amino acid decarboxylase using 5-hydroxytryptophan (5-HTP) as a substrate. It was recently shown that serotonin and its precursor have powerful antioxidant properties. The aim of this study was to evaluate the effect of reduction in 5-HT levels by parachlorophenylalanine (pCPA) and their restoration by 5-HTP administration on lipid peroxidation and antioxidant status in rat brain. Serotonin levels were decreased by p-chlorophenylalanine administration. The effect of p-chlorophenylalanine was counteracted by the intraperitoneal administration of 5-hydroxytryptophan. We evaluated the concentration of serotonin, malonyl dialdehyde and the status of antioxidants (GSH, catalase and superoxide dismutase) in brain. The results showed that p-chlorophenylalanine (300 mg/kg) induced a depletion of serotonin concentration and antioxidant status, as well as enhancing malonyl dialdehyde concentration in brain. The exogenous administration of 5-hydroxytryptophan prevented all effects induced by p-chlorophenylalanine in brain tissue. The recovery of the neurotransmitter concentration in brain was related to the reduction of lipid peroxide generation and improved antioxidant status. In conclusion, our study supports the view that the antioxidant properties of serotonin protect against basal oxidative stress in brain.

Ovariectomy exacerbates oxidative stress and cardiopathy induced by adriamycin.

Ovarian hormone depletion in ovariectomized experimental animals is a useful model with which to study the physiopathological consequences of menopause in women. It has been suggested that menopause is a risk factor for the induction of several cardiovascular disorders. In the present study we analyzed the effects of ovarian hormone depletion by ovariectomy (OVX) in a model of oxidative stress and cardiopathy induced by adriamycin (AD). To evaluate these effects, we measured parameters related to cardiac damage (creatinine kinase, lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase) and oxidative stress (malondialdehyde, catalase, superoxide dismutase, glutathione peroxidase, reduced glutathione, nitric oxide and carbonyl proteins) in cardiac tissue and erythrocytes. OVX was found to alter all markers of oxidative stress and cell damage in cardiac tissue. Similarly, the OVX-derived loss of ovarian hormones enhanced cardiac damage and oxidative stress induced by AD. Our results suggest that antioxidant status in cardiac tissue and erythrocytes is seriously compromised by OVX during the cardiomyopathy induced by AD in experimental animals. In conclusion, the absence of hormones caused by OVX or menopause may induce or accelerate pre-existing cardiovascular dysfunctions.

Transcranial magnetic stimulation attenuates cell loss and oxidative damage in the striatum induced in the 3-nitropropionic model of Huntington's disease.

An investigation was conducted on the effect of transcranial magnetic field stimulation (TMS) on the free radical production and neuronal cell loss produced by 3-nitropropionic acid in rats. The effects of 3-nitropropionic acid were evaluated by examining the following changes in: the quantity of hydroperoxides and total radical-trapping antioxidant potential (TRAP), lipid peroxidation products, protein carbonyl groups, reduced glutathione (GSH) content, glutathione peroxidase (GSH-Px), catalase and succinate dehydrogenase (SDH) activities; total nitrite and cell death [morphological changes, quantification of neuronal loss and lactate dehydrogenase (LDH) levels]. Our results reveal that 3-nitropropionic acid induces oxidative and nitrosative stress in the striatum, prompts cell loss and also shows that TMS prevents the harmful effects induced by the acid. In conclusion, the results show the ability of TMS to modify neuronal response to 3-nitropropionic acid.

Melatonin reduces apoptosis and necrosis induced by ischemia/reperfusion injury of the pancreas.

The pancreas is highly susceptible to the oxidative stress induced by ischemia/reperfusion (IR) injury leading to the generation of acute pancreatitis. Melatonin has been shown to be useful in the prevention of the damage by ischemia-reperfusion in liver, brain, myocardium, gut and kidney. The aim of the study was to evaluate the cytoprotective properties of melatonin against injury induced by IR in pancreas. The obstruction of gastro-duodenal and inferior splenic arteries induced pancreatic IR in male Wistar rats. Melatonin was intraperitoneally administered before or/and after IR injury. The animals were killed at 24 and 48 hr after reperfusion and there were evaluated parameters of oxidative stress (lipoperoxides, superoxide dismutase, catalase, glutathione peroxidase and reduced glutathione), glandular endocrine and exocrine function (lipase, amylase, insulin) and cell injury (apoptosis and necrosis). The IR induced a marked enhancement of oxidative stress and impaired pancreatic function. The histological analysis showed that IR induced acute pancreatitis with the accumulation of inflammatory infiltrate, disruption of tissue structure, cell necrosis and hemorrhage. Melatonin administration before or after pancreatic IR prevented all tissue markers of oxidative stress, biochemical and histological signs of apoptosis and necrosis, and restored glandular function. No histological signs of pancreatitis were observed 48 hr after reperfusion in 80% of the animals treated with melatonin, with only a mild edematous pancreatitis being observed in the remaining rats. Preventive or therapeutic administration of melatonin protected against the induction of oxidative stress and tissue injury, and restored cell function in experimental pancreatic IR in rats.

17 beta-Estradiol may affect vulnerability of striatum in a 3-nitropropionic acid-induced experimental model of Huntington's disease in ovariectomized rats.

The aim of present study was to clarify the role of female sex hormones in the development and course of neurodegenerative disease in an experimental model of Huntington's disease induced by 3-nitropropionic acid (NPA) (30 mg/kg intraperitoneally (i.p.)/day for 4 days) in ovariectomized rat. Gonadectomy prompted oxidative stress and cell death evaluated by the detection of caspase-3, whereas 3-nitropropionic acid enhanced the oxidative stress induced by ovariectomy and it triggered cell damage characterized by increases of LDH levels. These changes were prevented by administration of 17 beta-estradiol. Our findings suggested that: (i) ovariectomy induced oxidative stress and apoptosis in the brain; (ii) 3-nitropropionic acid exacerbated oxidative stress induced by ovariectomy and shifting cell to cell death; and (iii) 17 beta-estradiol administration decreased oxidative stress and cell death induced by ovariectomy and 3-nitropropionic acid. These results revealed that sex ovarian hormones play a important role in onset and development of neurodegenerative diseases, as well as neuroprotective effects of 17 beta-estradiol against the changes induced ovariectomy and ovariectomy plus 3-nitropropionic acid.

Estradiol and catecholestrogens protect against adriamycin-induced oxidative stress in erythrocytes of ovariectomized rats.

The beneficial effect of estrogens and catecholestrogens against oxidative stress associated tissue injury has been observed in different experimental model. The administration of adriamycin (AD) has been shown to enhance oxidative stress in different tissues. The lack of estrogens during ovariectomy (OVX) also induces oxidative damage in several tissues. However, the antioxidant properties of estrogens and catecholestrogens administration have not been evaluated in erythrocytes and plasma from ovariectomized animals in presence or not of AD toxicity. We have assessed the antioxidant capacity of 17beta-estradiol (17beta) and catecholestrogens against oxidative stress in erythrocytes and plasma induced by OVX in control animals or AD-treated animals. We analyzed the level of lipid peroxides, carbonyl proteins and reduced glutathione (GSH) as well as glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in plasma and erythrocytes. The results showed that AD, OVX and its combination increased lipid peroxides and carbonyl proteins, as well as reduced glutathione, superoxide dismutase and glutathione peroxidase activities in plasma and erythrocytes. The administration of 17beta and its metabolites (2- and 4-hydroxyestradiol) prevented all markers of oxidative stress induced by OVX in control and AD-treated animals. In conclusion, the administration of estrogens and cathecolestrogens counteract the oxidative stress in erythrocytes and plasma induced by OVX in presence or not toxic injury.

Protective effect of red wine on oxidative stress and antioxidant enzyme activities in the brain and kidney induced by feeding high cholesterol in rats.

The effect of red wine (400 ml/70 kg) on brain and kidney oxidative stress and antioxidative enzymes activities induced by cholesterol-enriched diet (supplemented with 1.65% of cholesterol (w/w) for 4 weeks) was studied in rats. When red wine (Montilla-Moriles, Cordoba, Spain) was simultaneously supplemented to high-cholesterol diet for 4 weeks, total cholesterol and lipid peroxidation products in the brain, kidney and erythrocytes significantly decreased compared with the high-cholesterol, while GSH content and antioxidative enzymes activities enhanced. On the other hand, the urinary excretion of urea, creatinine and albumin decreased significantly. These results suggest that red wine may have a neuro-nephroprotective effect against oxidative stress and hypercholesterolemia.

Effect of 17-beta-estradiol administration during adriamycin-induced cardiomyopathy in ovariectomized rat.

The incidence of cardiovascular diseases in humans differs in relation to the age of the patient. Although women suffer less than men from cardiovascular disorders during 15-55 years, after this period the incidence is equivalent in both sexes. This data suggests a cytoprotective effect of estrogens against cardiovascular disease. The estrogens, especially 17-beta-estradiol, are important antioxidant molecules with potential cytoprotective properties during oxidant/antioxidant disbalance induced by oxidative stress. Oxidative stress is often the underlying mechanism during vascular alterations and cardiac damage. The present study evaluated the role of ovariectomy and/or 17-beta-estradiol administration on antioxidant status and lipid peroxidation during cardiac injury induced by adriamycin. Different parameters were measured, including hemodynamic response (arterial pressure and cardiac frequency), lipid peroxidation products (malondialdehyde), protein carbonylation, antioxidant status (reduced glutathione, glutathione peroxidase, superoxide dismutase and catalase), and cardiac injury (creatinine kinase, lactate dehydrogenase, aspartate and alanine aminotransferase). Our study showed that 17-beta-estradiol reduced all of the parameters related to oxidative stress and cardiac injury in ovariectomized rats treated with adriamycin.

Parachlorophenylalanine exacerbates oxidative stress induced by gentamicin in rats.

The present work studies the effect of parachlorophenylalanine (PCPA, 200 mg/kg intraperitoneally/48 hr for 7 days) on the oxidative stress and nephropathy induced by gentamicin (80 mg/kg intraperitoneally/daily for 7 days) in Wistar rats. The effect of PCPA on lipid peroxidation products and reduced glutathione content in renal and brain tissue, as well as on 5HT content in brain was assessed. Catalase and superoxide dismutase activities were determined in brain tissue. Blood urea nitrogen and creatinine in plasma and total protein content in urine were also measured. Gentamicin caused significant increases in proteinuria, non-protein nitrogen compounds and lipid peroxidation markers, together with decreases in both reduced glutathione content in renal and brain tissue and enzymatic activities in brain homogenates. PCPA harnessed the effect of gentamicin in the brain and the kidney, while PCPA alone induced brain oxidative stress. These results support the prooxidant action of PCPA in brain tissue and its capacity to exacerbate the oxidative stress and renal dysfunction induced by gentamicin, as well as the possible antioxidant property of serotonin.