Interaction of the adenosine A1 receptor agonist N6-cyclopentyladenosine and κ-opioid receptors in rat spinal cord nociceptive reflexes.

Antinociception induced by the adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA) is linked to opioid receptors. We studied the subtype of receptors to which CPA action is related, as well as a possible enhancement of antinociception when CPA is coadministered with opioid receptor agonists. Spinal cord neuronal nociceptive responses of male Wistar rats with inflammation were recorded using the single motor unit technique. CPA antinociception was challenged with naloxone or norbinaltorphimine. The antinociceptive activity of fentanyl and U-50488H was studied alone and combined with CPA. Reversal of CPA antinociception was observed with norbinaltorphimine (82.9±13% of control) but not with low doses of naloxone (27±8% of control), indicating an involvement of κ-opioid but not µ-opioid receptors. Low doses of CPA did not modify fentanyl antinociception. However, a significant enhancement of the duration of antinociception was seen when U-50488H was coadministered with CPA. We conclude that antinociception mediated by CPA in the spinal cord is associated with activation of κ-opioid but not µ-opioid receptors in inflammation. In addition, coadministration of CPA and κ-opioid receptor agonists is followed by significantly longer antinociception, opening new perspectives in the treatment of chronic inflammatory pain.

Enhancement of wind-up by the combined administration of adenosine A1 receptor ligands on spinalized rats with carrageenan-induced inflammation.

The adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA) is very effective in reducing wind-up in intact but not in spinalized adult rats with carrageenan-induced inflammation, suggesting an adenosine-mediated supraspinal modulation. Since wind-up is a spinal cord mediated phenomenon but highly influenced by descending modulatory systems, especially in situations of sensitization, we assessed the possible involvement of adenosine in the modulation of wind-up. We studied the effect of the adenosine A(1) receptor antagonist 8-cyclopentyl-1,3-dimethylxanthine (CPT) in the presence and in the absence of the adenosine A(1) receptor agonist CPA. The experiments were carried out in spinalized male Wistar rats under alpha-chloralose anaesthesia. Withdrawal reflexes, studied as single motor units, were activated by noxious mechanical and high-intensity repetitive electrical stimulation (wind-up). While CPA and CPT were not able to induce any change on wind-up when injected alone, the combination of the two drugs, in any order, lead to an important enhancement of wind-up. This enhancement not always paralleled an increase of responses to noxious mechanical stimulation, indicating that the effect is mainly located in the spinal cord. In addition, the enhancement of wind-up was not further increased by the administration of the opioid receptor antagonist naloxone. We conclude that the depression of the wind-up phenomenon observed in spinalized animals is, at least in part, dependent of adenosine systems and can be relieved by the combined administration of CPA and CPT.

Pro-Inflammatory Cytokines in Nasopharyngeal Aspirate From Hospitalized Children With Respiratory Syncytial Virus Infection With or Without Rhinovirus Bronchiolitis, and Use of the Cytokines as Predictors of Illness Severity.

Respiratory syncytial virus (RSV) and human rhinovirus (HRV) respiratory infection in children induce production of inflammatory interleukins (ILs) in the respiratory epithelium. As IL(s) determine the severity of illness, the purpose of this study was to identify the pro-inflammatory IL(s) that could be predictor(s) of clinical severity. One hundred and fifteen patients <2 years old with bronchiolitis due to RSV and /or HRV and 38 controls were selected from a hospital and an outpatient clinic. Clinical data of all patients were recorded. Severity was defined by the number of days with oxygen need. Nasopharyngeal aspirates (NPA) were collected to perform viral diagnosis by quantitative reverse transcription and polymerase chain reaction (qRT-PCR) and to quantify ILs: TNF-α, IL-10, IL-6, IL-1ß, and IL-8, by flow cytometry. Simple and multiple regression and receiver operating characteristic (ROC) curves were used for statistical analysis. Of the patients selected 60 were single RSV, 28 RSV associated to HRV, and 27 single HRV. All patients (115) showed significantly higher IL levels when compared with controls. Levels of IL-6, IL-1ß, and IL-8 detected in NPA from RSV single and associated to HRV were significantly higher than HRV infected and positively associated with days requiring O2.Levels of IL-6, IL-1ß, and IL-8 detected in NPA from patients infected with RSV only or with both RSV and HRV are increased, and any of those 3 cytokines may have a predictive value for the number of days with need of supplemental oxygen.

Spinal vs. supraspinal antinociceptive activity of the adenosine A(1) receptor agonist cyclopentyl-adenosine in rats with inflammation.

The adenosine A(1) receptor is involved in spinal cord antinociception. As its role at supraspinal sites is not well known, we studied the systemic effects of its agonist N-cyclopentyl-adenosine (CPA) in single motor units from adult-spinalized, intact and sham-spinalized rats. CPA was not effective after spinalization, but it was very effective in intact animals (ID50: 92+/-1.3 microg/kg, noxious pinch) and over 10-fold more potent in sham-spinalized animals (ID50 of 8.3+/-1 microg/kg). Wind-up was also inhibited by CPA. We also studied the effect of CPA in the immature spinal cord preparation, where CPA dose-dependently inhibited responses to low (IC50s: 9+/-0.7 and 7.7+/-1.3 nM) and high intensity stimulation (IC50s: 4.9+/-0.5 and 12.1+/-2 nM). We conclude that the integrity of the spinal cord is crucial for the antinociceptive activity of systemic CPA in adult rats but not in immature rats, not yet influenced by a completely developed supraspinal control.

[Nosocomial urinary infection due to Trichosporon asahii. First two cases in Chile]. / Infección urinaria nosocomial por Trichosporon asahii. Primeros dos casos en Chile.

We present two cases of nosocomial urinary tract infection due to Trichosporon asahii in intensive care unit patients with bladder catheter from two hospitals in Santiago, Chile. Both patients had an several catheters and bacterial infections that required the use of antibiotic therapy. One strain showed in vitro resistance to amphotericin B. Both strains were susceptible to fluconazole, but presented MIC with dose-dependent susceptibility to ketoconazole and itraconazole. This is the first report showing T. asahii as urinary tract infection agent in Chile.

[Yeast carriage on the hands of Medicine students]. / Portación de levaduras en manos de estudiantes de Medicina.

The main focus of our study was to determine the prevalence of yeasts on the hands of Medicine students and other students not related to the Health care system. Between July 1999 and July 2000, 253 students of Medicine (163) and Engineering (90) were studied. Medicine students were grouped as basic (71), pre-clinical (62) and clinical (30). The Engineering's students were divided into three groups according to the years of study. The total yeasts carried on the hands of Medicine's students were 16%. By group the results were 7% for the basic, 19% for the pre-clinical and 30% for the clinical and the prevalence of the two last groups was higher than the first one. The Engineering's students showed 9% prevalence without differences between years of career. The yeast carriage in the clinical group was higher than the equivalent control group (10%). The species frequently encountered were Rhodotorula mucilaginosa (Rhodotorula rubra) and Candida parapsilosis, with a tendency to a higher species diversity and colony count in the pre-clinical and clinical groups. This finding could explain the high prevalence of candidemia by C. parapsilosis in our hospitals. In summary, yeast carriage, diversity and quantity in Medicine students were related to the time of being in the hospital environment.

Interaction of the adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA) and opioid receptors in spinal cord nociceptive reflexes.

AIMS: We previously observed that the adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA) is a very effective antinociceptive agent on intact but not on spinalized adult rats with inflammation. Since a close connection between opioid and adenosine A1 receptors has been described, we studied a possible relationship between these systems in the spinal cord. MAIN METHODS: CPA-mediated antinociception was challenged by the selective adenosine A1 receptor antagonist 8-cyclopentyl-1, 3-dimethylxanthine (CPT) and by the opioid receptor antagonist naloxone on male adult Wistar rats with carrageenan-induced inflammation. Withdrawal reflexes activated by noxious mechanical and electrical stimulation were recorded using the single motor technique in intact and sham-spinalized animals. KEY FINDINGS: CPA was very effective in intact and sham spinalized rats but not in spinalized animals. Full reversal of CPA antinociception was observed with i.v. 1mg/kg of naloxone but not with 20mg/kg of CPT i.v. in responses to noxious mechanical and electrical stimulation. CPT fully prevented CPA from any antinociceptive action whereas naloxone did not modify CPA activity. These results suggest a centrally-mediated action, since CPA depressed the wind-up phenomenon which is derived of the activity of spinal cord neurons. SIGNIFICANCE: The present study provides strong in vivo evidence of an antinociceptive activity mediated by the adenosine A1 receptor system in the spinal cord, linked to an activation of opioid receptors in adult animals with inflammation.

Timectomía por cirugía torácica videoasistida, VATS, en miastenia gravis / Thymectomy by videoassisted thoracic surgery, VATS, in myasthenia gravis

Se reportan 10 pacientes con miastenia gravis a los cuales se les resecó el timo con técnica videotoracoscópica en este centro universitario. Desde mayo de 1997 a agosto de 2000, 10 pacientes que padecían de miastenia gravis, 7 mujeres y 3 hombres, con una edad promedio de 33 años y un rango de edad de 17 a 52 años, fueron sometidos a timectomía utilizando la técnica de VATS. El tiempo promedio de evolución de la enfermedad fue de aproximadamente 15 meses con un rango de 2 a 26 meses. La técnica quirúrgica incluyó una vía de abordaje por el lado derecho en 9 pacientes y bilateral en 1. El tiempo promedio de operación fue de aproximadamente 3 horas, con un rango de 1 a 4 horas. No hubo mortalidad operatoria y ningún paciente presentó complicaciones intra o postoperatorias. Asimismo no hubo casos que requirieran ventilación mecánica. El tiempo promedio de días postoperatorio fue de aproximadamente 2 días con un rango de 1 a 5 días. El análisis de este grupo nos muestra que los resultados son buenos en dos casos, con mejoría parcial en 4 casos. El tiempo de control aún breve nos sugiere que podrían mejorar. Así mismo el tiempo de evolución parece aconsejar indicaciones quirúrgicas más precoces. Se concluye por los resultados obtenidos que la timectomía por VATS es apropiado para el tratamiento de la miastenia gravis, lo cual concuerda con las informaciones obtenidas de la literatura mundial

Aspectos epidemiológicos de las infecciones del torrente sanguíneo por levaduras. Confrontando nuestra realidad con el mundo / Epidemiological aspects of circulatory infections by yeasts. Our situation compared with global conditions

Blood stream infections caused by yeasts have undergone considerable increases since the 1980's, showing a change in dynamics of distribution of the agents beginning in the 1990's. This type of infection is primarily nosocomial, and fundamentally affects immunodeppressed individuals, and those within intensive care units. General and specific epidemiological data are reviewed in this study, including both national and global information related to clinical and diagnostic aspects of yeast fungemias. An updated overview of the topic is presented for professionals and specialists in health fields.

La infección del torrente sanguíneo, causada por levaduras, ha experimentado un aumento considerable desde la década de los 80, mostrando a partir de los 90 un cambio dinámico en la distribución de los agentes. Esta infección es mayoritariamente nosocomial y afecta fundamentalmente a pacientes inmunodeprimidos e internados en unidades críticas. En la presente revisión se muestran antecedentes epidemiológicos generales y específicos, tanto nacionales como extranjeros, relacionados con la clínica y el diagnóstico de fungemia por levaduras, entregando una visión actualizada del tema a los distintos profesionales y especialistas del área de la salud.