María Jesús Muñoz

Time trends and impact of upper and lower gastrointestinal bleeding and perforation in clinical practice.

OBJECTIVES:Changing patterns in medical practice may contribute to temporal changes in the incidence of upper and lower gastrointestinal (GI) complications. There are limited data on the incidence of lower GI complications in clinical practice and most studies that have been done have serious methodological limitations to inferring the actual burden of this problem. The aims of this study were to analyze time trends of hospitalizations resulting from GI complications originating both from the upper and lower GI tract in the general population, and to determine the risk factors, severity, and clinical impact of these GI events.METHODS:This was a population-based study of patients hospitalized because of GI complications in 10 general hospitals between 1996 and 2005 in Spain. We report the age- and gender-specific rates, estimate the regression coefficients of the upper and lower GI event trends, and evaluate the severity and associated risk factors. GI hospitalization charts were validated by an independent review of large random samples of unspecific and specific codes distributed among all hospitals and study years.RESULTS:Upper GI complications fell from 87/100,000 persons in 1996 to 47/100,000 persons in 2005, whereas lower GI complications increased from 20/100,000 to 33/100,000. Overall, mortality rates decreased, but the case fatality remained constant over time. Lower GI events had a higher mortality rate (8.8 vs. 5.5%), a longer hospitalization (11.6±13.9 vs. 7.9±8.8 days), and higher resource utilization than did upper GI events. The use of nonsteroidal anti-inflammatory drugs (NSAIDs) without concomitant proton pump inhibitor was more frequently recorded among upper GI complications than among lower GI complications. When comparing upper GI events with lower GI events, we found that male gender (adjusted odds ratio (OR): 1.94; 95% confidence interval (CI): 1.70–2.21), and recorded NSAID use (OR: 1.92; 95% CI: 1.60–2.30) were associated to a greater extent with upper GI events, whereas older age (OR: 0.83; 95% CI: 0.77–0.89), number of comorbidities (OR: 0.91; 95% CI: 0.86–0.96), and having a diagnosis in recent years (OR: 0.92; 95% CI: 0.90–0.94) were all associated to a greater extent with lower GI events than with upper GI events after adjusting for age, sex, hospitalization, and discharge year.CONCLUSIONS:Over the past decade, there has been a progressive change in the overall picture of GI events leading to hospitalization, with a clear decreasing trend in upper GI events and a significant increase in lower GI events, causing the rates of these two GI complications to converge. Overall, mortality has also decreased, but the in-hospital case fatality of upper or lower GI complication events has remained constant. It will be a challenge to improve future care in this area unless we develop new strategies to reduce the number of events originating in the lower GI tract, as well as reducing their associated mortality.

Optimal methods to characterize the G93A mouse model of ALS

In the present study, we used the SOD1 (G93A) mutant transgenic mice as a model of amyotrophic lateral sclerosis (ALS). This model is widely used as a laboratory tool to study experimental treatments in vivo for ALS to investigate new therapeutic strategies for this neurodegenerative disease. Such studies require the objective quantification of different parameters while mice develop the disease. We have applied a battery of different and specific tests: scoring of motor deficits by a trained observer, weighing, survival measure, hanging wire test, rotarod task and electromyography, most of them commonly used to evaluate G93A animals. We have critically compared these methods, showing the significant influence of gender on the onset of symptoms, and the optimal moment to apply each test. These results should be taken into account in future therapeutic assays on this ALS model.

Risk of Upper and Lower Gastrointestinal Bleeding in Patients Taking Nonsteroidal Anti-inflammatory Drugs, Antiplatelet Agents, or Anticoagulants

BACKGROUND & AIMS Treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) or low-dose aspirin is associated with increased risk of upper gastrointestinal bleeding. There is little evidence on the risk of lower gastrointestinal bleeding with NSAIDs, antiplatelet agents (APAs), or anticoagulants. We aimed to quantify the relative risk (RR) of upper and lower gastrointestinal bleeding associated with use of NSAIDs, APAs, or anticoagulants. METHODS We performed a case-control study that used data collected from consecutive patients hospitalized for gastrointestinal bleeding (563 upper, mean age, 63.6 ± 16.7 years and 415 lower, mean age, 70.8 ± 13.8 years), confirmed by endoscopy or other diagnostic procedures. Unhospitalized patients were used as controls (n = 1008) and matched for age, hospital, and month of admission. Drug use was considered current when taken within 7 days or less before hospitalization. RRs and 95% confidence intervals (CIs) were estimated by unconditional logistic regression analysis. RESULTS Use of anticoagulants, low-dose aspirin, and other drugs (non-aspirin-APA, 82.3% thienopiridines) was associated with upper and lower gastrointestinal bleeding; the risk was 2-fold higher for anticoagulants (RR, 4.2; 95% CI, 2.9-6.2) than for low-dose aspirin (RR, 2.1; 95% CI, 1.4-3.3) or other non-aspirin-APA drugs (RR, 2.0; 95% CI, 1.6-2.6). NSAID use was also associated with increased risk of gastrointestinal bleeding and greater for upper (RR, 2.6; 95% CI, 2.0-3.5) than lower gastrointestinal bleeding (RR, 1.4; 95% CI, 1.0-1.9). Use of proton pump inhibitors was associated with reduced risk of upper, but not lower, gastrointestinal bleeding. CONCLUSIONS Anticoagulants, low-dose aspirin, NSAIDs, and other non-aspirin-APA drugs are associated with increased risk of upper and lower gastrointestinal bleeding. Use of anticoagulants appears to be the strongest risk factor for gastrointestinal bleeding.

Passive nonlinear elastic behaviour of skeletal muscle: Experimental results and model formulation

The goal of this study was to characterize the passive elastic behaviour of muscle and tendon tissues of rat tibialis anterior. For that purpose, tissue samples from 3 month old female Wistar rats (210+/-11g) were mechanically tested in vitro. Moreover, an in vivo device was developed to measure the muscle-tendon unit response to increasing load. Mechanical tests, consisting of uniaxial loading along the longitudinal axis of tendon and muscle strips, revealed the nonlinear mechanical behaviour of these tissues. A material model was formulated and its parameters fit to the experimental data using the Levenberg-Marquardt optimization algorithm. The fit goodness was assessed and R(2) values close to 1 and very low epsilon values were obtained. The passive behaviour of a future finite element model of a muscle-tendon unit will be validated against the in vivo passive extension tests by comparing the reaction force-extension curves.

Fragment C of tetanus toxin, more than a carrier. Novel perspectives in non-viral ALS gene therapy

The non-toxic carboxy-terminal fragment of tetanus toxin heavy chain (TTC) has been implicated in the activation of cascades responsible for trophic actions and neuroprotection by inhibition of apoptosis. Previous in vitro studies have described signalling pathways that underlie the administration of TTC to neurons. We investigated whether these properties were maintained in a mouse model of neurodegenerative disease. Naked DNA encoding for TTC was injected intramuscularly and neuromuscular function and clinical behaviour were monitored until endstage in the transgenic SOD1G93A mouse model that expresses a mutant variant of human superoxide dismutase 1 (SOD1). Our results indicate that TTC treatment ameliorated the decline of hindlimb muscle innervation, significantly delayed the onset of symptoms and functional deficits, improved spinal motor neuron survival, and prolonged lifespan. Furthermore, we found that caspase-1 and caspase-3 proapoptotic genes were down-regulated in the spinal cord of treated mice. Western blot analysis showed that the active form of caspase-3 was also down-regulated after TTC treatment and survival signals, such as the significant phosphorylation of serine/threonine protein kinase Akt, were also detected. These results suggest that fragment C of tetanus toxin, TTC, provides a potential therapy for neurodegenerative diseases.

An approach for mapping the vulnerability of European Union soils to antibiotic contamination.

Release of antibiotics into the environment through the agricultural reuse of animal manure is considered a cause of chronic environmental exposure that often leads to adverse ecotoxicological effects, as well as to the introduction of antibiotic-resistant bacteria into the environment. The vulnerability of soil to antibiotic contamination plays a major role in determining the extent of the contamination and the likelihood of the emergence of antibiotic resistance and the appearance of ecotoxicological effects. It depends on soil characteristics, which vary across Europe, and antibiotic characteristics, which vary across drug classes. Understanding how soil vulnerability varies geographically for different veterinary medicinal products would be very useful for resource allocation among surveillance programmes. This paper performs risk analysis of the EU region for 12 antimicrobials using a spatial assessment performed in four steps. First, antibiotic release was estimated based on livestock density. Then exposure was estimated based on antimicrobial soil contamination. Third, consequences were modelled based on soil uses. Finally, risk was estimated by combining release, exposure and consequences using spatial multicriteria decision analysis. A final risk value for soil vulnerability was calculated for each antibiotic studied and displayed in chloropletic maps (ArcGIS 9.3). Furthermore, the Getis-Ord Gi statistic was used to identify clusters of areas at high risk for antibiotic soil contamination. Enrofloxacin was the highest-risk antibiotic in the European Union, followed by tetracyclines, tylosin and sulfodiazine. The highest risk values were found in Belgium, Ireland, Netherlands, Switzerland, Denmark, Germany and the UK. The results suggest that this methodology can be used successfully for evaluating the contamination potential of antibiotics over large areas with limited input data. This work is a preliminary step towards prioritising the use of veterinary medicinal products (VMPs), orientating monitoring studies and antimicrobial surveillance programmes, and informing sustainable decision-making for interventions designed to mitigate the risk of VMPs.

Screening for several potential pathogens in feral pigeons (Columba livia) in Madrid.

BackgroundPathogens with the zoonotic potential to infect humans, such as Campylobacter jejuni, Campylobacter coli and Chlamydophila psittaci, can be found in feral pigeons (Columba livia). Given the high density of these birds in the public parks and gardens of most cities, they may pose a direct threat to public health.MethodsA total of 118 pigeons were captured in three samplings carried out in 2006-2007 in public parks and gardens in Madrid, Spain. Standard haematological and morphological analyses were carried out on the pigeons. PCR was used to screen for the presence of Campylobacter jejuni, C. coli and Chlamydophila psittaci. Positive samples were confirmed by DNA sequencing.ResultsThe analyses demonstrated a high prevalence of Chlamydophila psittaci (52.6%) and Campylobacter jejuni (69.1%) among the birds captured. In contrast, Campylobacter coli was rarely detected (1.1%).ConclusionsPigeons in Madrid can carry Chlamydophila psittaci and Campylobacter jejuni. They may be asymptomatic or subclinical carriers of both pathogens.

Genetic Biomarkers for ALS Disease in Transgenic SOD1G93A Mice

The pathophysiological mechanisms of both familial and sporadic Amyotrophic Lateral Sclerosis (ALS) are unknown, although growing evidence suggests that skeletal muscle tissue is a primary target of ALS toxicity. Skeletal muscle biopsies were performed on transgenic SOD1G93A mice, a mouse model of ALS, to determine genetic biomarkers of disease longevity. Mice were anesthetized with isoflurane, and three biopsy samples were obtained per animal at the three main stages of the disease. Transcriptional expression levels of seventeen genes, Ankrd1, Calm1, Col19a1, Fbxo32, Gsr, Impa1, Mef2c, Mt2, Myf5, Myod1, Myog, Nnt, Nogo A, Pax7, Rrad, Sln and Snx10, were tested in each muscle biopsy sample. Total RNA was extracted using TRIzol Reagent according to the manufacturers protocol, and variations in gene expression were assayed by real-time PCR for all of the samples. The Pearson correlation coefficient was used to determine the linear correlation between transcriptional expression levels throughout disease progression and longevity. Consistent with the results obtained from total skeletal muscle of transgenic SOD1G93A mice and 74-day-old denervated mice, five genes (Mef2c, Gsr, Col19a1, Calm1 and Snx10) could be considered potential genetic biomarkers of longevity in transgenic SOD1G93A mice. These results are important because they may lead to the exploration of previously unexamined tissues in the search for new disease biomarkers and even to the application of these findings in human studies.

Lack of a synergistic effect of a non-viral ALS gene therapy based on BDNF and a TTC fusion molecule.

BackgroundAmyotrophic lateral sclerosis (ALS) is one of the most devastating neurodegenerative diseases. Neurotrophic factors have been widely tested to counteract neurodegenerative conditions, despite their unspecific neuronal access. The non-toxic C-terminal fragment of the tetanus toxin (TTC) heavy chain has been studied not only as a carrier molecule to the CNS but also as a neuroprotective agent. Because the neurotrophic effects of BDNF have been demonstrated in vitro and in vivo, the question addressed in this work is whether a fusion molecule of BDNF-TTC may have a synergistic effect and enhance the neuroprotective properties of TTC alone in a mouse model of ALS.MethodsRecombinant plasmid constructs (pCMV-TTC and pCMV-BDNF-TTC) were injected into the quadriceps femoris and triceps brachialis muscles of SOD1G93A transgenic mice at 8 weeks of age. The hanging wire and rotarod tests were performed to assess motor coordination, strength and balance. Electrophysiological tests, morphological assays of spinal cord sections of L2 and L4 segments, and gene and protein expression analyses were performed. The Kaplan-Meier survival analysis test was used for comparisons of survival. Multiple comparisons of data were analyzed using a one-way analysis of variance (ANOVA).ResultsTreatment with the fusion-molecule BDNF-TTC and with TTC alone significantly delayed the onset of symptoms and functional deficits of SOD1G93A mice. Muscle innervation was partially preserved with these treatments, and the number of surviving motoneurons in L2 spinal cord segment was increased particularly by the fusion protein induction. Inhibition of pro-apoptotic protein targets (caspase-3 and Bax) and significant phosphorylation of Akt and ERK were also found in the spinal cord of treated mice.ConclusionsSignificant improvements in behavioral and electrophysiological results, motoneuron survival and anti-apoptotic/survival-activated pathways were observed with BDNF-TTC treatment. However, no synergistic effect was found for this fusion molecule. Although BDNF in the fusion molecule is capable of activating autocrine and neuroprotective pathways, TTC treatment alone yielded similar neuroprotection. Therefore, an accurate study of the neuroprotective effects of TTC fusion molecules should be performed to obtain a better understanding of its effects.

Altered Expression of Myogenic Regulatory Factors in the Mouse Model of Amyotrophic Lateral Sclerosis

Background: In the superoxide dismutase 1 (SOD1)-G93A mouse model of amyotrophic lateral sclerosis (ALS), skeletal muscle is a key target of mutant SOD1 toxicity. However, the expression of factors that control the regenerative potential of the muscle is unknown in this model. Objective: To characterize the expression of satellite cell marker Pax7 and myogenic regulatory factors (MRF) in skeletal muscle of SOD1-G93A mice at different stages of the disease. Methods: The expressions of Pax7, Myod1, Myf5 and myogenin (Myog) were determined by quantitative real-time PCR and by Western blotting from the grouped gastrocnemius, quadriceps and soleus muscles of SOD1-G93A mice at presymptomatic, symptomatic and terminal stages of the disease, and from surgically denervated wild-type gastrocnemius muscles. Results:Pax7 mRNA and MYF5 protein were upregulated in presymptomatic mice, coinciding with increased muscle damage marker Rrad and chemokine Ccl5. All MRF transcripts and most proteins (excluding MYOG) were increased, starting from 3 months of age, simultaneously with increased expression of denervation marker Chrna1. However, in the terminal stage, no protein increase was evident for Pax7 or any of the MRF despite the increased mRNA levels. The transcripts for chemokine Ccl2 and chemokine receptor Cxcr4 were increased starting from the onset of symptoms. Conclusions: The characterization of Pax7 and MRF in SOD1-G93A mice reveals a progressive induction of the myogenic program at the RNA level, but a blunted protein level response at late stages of the disease. Altered posttranscriptional and posttranslational mechanisms likely to operate, as well as the potential role of chemokine signaling in mutant SOD1 muscle, are discussed.