Monitoreo de vancomicina administrada intraventricularmente en lactantes durante el tratamiento de ventriculitis

The objective of this study was to establish guidelines for the monitoring of intraventricularly administeredVancomycin in infants.Eleven patients with ventriculo-peritoneal shunts who developed ventriculitis were included in the study.All patients were given an intraventricular (IVT) dose of Vancomycin. Cerebrospinal fluid (CSF)samples were analysed and pharmacokinetic parameters: elimination rate constant (ke) and distributionvolume (Vd) were calculated in order to adjust the dose. Mean values of Vd and elimination half-lifefor these patients were 244 (± 162) mL and 37.1 (±23.3) hours respectively.A great variability in the Vd was observed in some patients. This change in Vd correlates with problemsin the ventricle size or with septated ventricles. In all cases a new dose was suggested according to thecalculated parameters.Due to variations in the system throughout therapy, a protocol for CSF samples collection was proposedin order to individualise Vancomycin dosage according to pharmacokinetic parameters.El objetivo de este estudio fue establecer pautas para el monitoreo de Vancomicina cuando la misma esadministrada intraventricularmente en lactantes.En este estudio se incluyeron once pacientes con derivaciones ventrículo-peritoneal. Todos los pacientesrecibieron una dosis de Vancomicina intraventricular (IVT). Las muestras de líquido cefalorraquídeo(LCR) fueron analizadas y se calcularon los parámetros farmacocinéticos: constante de velocidad deeliminación (ke) y volumen de distribución (Vd) para poder llevar a cabo un ajuste posológico. Lasmedias referidas al Vd y a la semivida de eliminación para estos pacientes fueron de 244(±162) mL y37.1(±23.3) horas respectivamente.En algunos pacientes se observó una gran variabilidad en el Vd. Este cambio en Vd se correlacionó conproblemas en el tamaño ventricular o con ventrículos septados. En todos los casos, se propuso una nuevadosis de acuerdo a los parámetros calculados.Debido a variaciones en el sistema a lo largo de la terapia, se propuso un protocolo para la recolecciónde muestras de LCR de forma tal de individualizar la dosis de Vancomicina con los parámetros farmacocinéticosobtenidos

Human plasmacytoid dendritic cells elicited different responses after infection with pathogenic and nonpathogenic Junin virus strains

The arenavirus Junin virus (JUNV) is the etiologic agent of Argentine hemorrhagic fever. We characterized the JUNV infection of human peripheral blood-derived plasmacytoid dendritic cells (hpDC), demonstrating that hpDC are susceptible to infection with the C#1 strain (attenuated) and even more susceptible to infection with the P (virulent) JUNV strain. However, hpDC elicited different responses in terms of viability, activation, maturation, and cytokine expression after infection with both JUNV strains.Instituto de Biotecnologia y Biologia Molecula

Human plasmacytoid dendritic cells elicited different responses after infection with pathogenic and nonpathogenic Junin virus strains

The arenavirus Junin virus (JUNV) is the etiologic agent of Argentine hemorrhagic fever. We characterized the JUNV infection of human peripheral blood-derived plasmacytoid dendritic cells (hpDC), demonstrating that hpDC are susceptible to infection with the C#1 strain (attenuated) and even more susceptible to infection with the P (virulent) JUNV strain. However, hpDC elicited different responses in terms of viability, activation, maturation, and cytokine expression after infection with both JUNV strains.Instituto de Biotecnologia y Biologia Molecula

Junín Virus Infection of Human Hematopoietic Progenitors Impairs In Vitro Proplatelet Formation and Platelet Release via a Bystander Effect Involving Type I IFN Signaling

Argentine hemorrhagic fever (AHF) is an endemo-epidemic disease caused by Junín virus (JUNV), a member of the arenaviridae family. Although a recently introduced live attenuated vaccine has proven to be effective, AHF remains a potentially lethal infection. Like in other viral hemorrhagic fevers (VHF), AHF patients present with fever and hemorrhagic complications. Although the causes of the bleeding are poorly understood, impaired hemostasis, endothelial cell dysfunction and low platelet counts have been described. Thrombocytopenia is a common feature in VHF syndromes, and it is a major sign for its diagnosis. However, the underlying pathogenic mechanism has not yet been elucidated. We hypothesized that thrombocytopenia results from a viral-triggered alteration of the megakaryo/thrombopoiesis process. Therefore, we evaluated the impact of JUNV on megakaryopoiesis using an in vitro model of human CD34+ cells stimulated with thrombopoietin. Our results showed that CD34+ cells are infected with JUNV in a restricted fashion. Infection was transferrin receptor 1 (TfR1)-dependent and the surface expression of TfR1 was higher in infected cultures, suggesting a novel arenaviral dissemination strategy in hematopoietic progenitor cells. Although proliferation, survival, and commitment in JUNV-infected cultures were normal, viral infection impaired thrombopoiesis by decreasing in vitro proplatelet formation, platelet release, and P-selectin externalization via a bystander effect. The decrease in platelet release was also TfR1-dependent, mimicked by poly(I:C), and type I interferon (IFN α/β) was implicated as a key paracrine mediator. Among the relevant molecules studied, only the transcription factor NF-E2 showed a moderate decrease in expression in megakaryocytes from either infected cultures or after type I IFN treatment. Moreover, type I IFN-treated megakaryocytes presented ultrastructural abnormalities resembling the reported thrombocytopenic NF-E2−/− mouse phenotype. Our study introduces a potential mechanism for thrombocytopenia in VHF and other diseases associated with increased bone marrow type I IFN levels

Increased Levels of Leukocyte-Derived MMP-9 in Patients with Stable Angina Pectoris

Objective: There is a growing interest for matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in plasma as novel biomarkers in coronary artery disease (CAD). We aimed to identify the sources of MMP-8, MMP-9, TIMP-1 and TIMP-2 among peripheral blood cells and further explore whether gene expression or protein release was altered in patients with stable angina pectoris (SA). Methods: In total, plasma MMP-9 was measured in 44 SA patients and 47 healthy controls. From 10 patients and 10 controls, peripheral blood mononuclear cells (PBMC) and neutrophils were isolated and stimulated ex vivo. MMPs, TIMPs and myeloperoxidase were measured in plasma and supernatants by ELISA. The corresponding gene expression was measured by real-time PCR. Results: Neutrophils were the dominant source of MMP-8 and MMP-9. Upon moderate stimulation with IL-8, the neutrophil release of MMP-9 was higher in the SA patients compared with controls (p,0.05). In PBMC, the TIMP-1 and MMP-9 mRNA expression was higher in SA patients compared with controls, p,0.01 and 0.05, respectively. There were no differences in plasma levels between patients and controls except for TIMP-2, which was lower in patients, p,0.01. Conclusion: Measurements of MMPs and TIMPs in plasma may be of limited use. Despite similar plasma levels in SA patients and controls, the leukocyte-derived MMP-9 and TIMP-1 are significantly altered in patients. The findings indicate that th

Monitoring of intraventricularly administered vancomycin in infants in the treatment of ventriculitis

El objetivo de este estudio fue establecer pautas para el monitoreo de Vancomicina cuando la misma es administrada intraventricularmente en lactantes. En este estudio se incluyeron once pacientes con derivaciones ventrículo-peritoneal. Todos los pacientes recibieron una dosis de Vancomicina intraventricular (IVT). Las muestras de líquido cefalorraquídeo (LCR) fueron analizadas y se calcularon los parámetros farmacocinéticos: constante de velocidad de eliminación (ke) y volumen de distribución (Vd) para poder llevar a cabo un ajuste posológico. Las medias referidas al Vd y a la semivida de eliminación para estos pacientes fueron de 244(±162) mL y 37.1(±23.3) horas respectivamente. En algunos pacientes se observó una gran variabilidad en el Vd. Este cambio en Vd se correlacionó con problemas en el tamaño ventricular o con ventrículos septados. En todos los casos, se propuso una nueva dosis de acuerdo a los parámetros calculados. Debido a variaciones en el sistema a lo largo de la terapia, se propuso un protocolo para la recolección de muestras de LCR de forma tal de individualizar la dosis de Vancomicina con los parámetros farmacocinéticos obtenidos.The objective of this study was to establish guidelines for the monitoring of intraventricularly administered Vancomycin in infants. Eleven patients with ventriculo-peritoneal shunts who developed ventriculitis were included in the study. All patients were given an intraventricular (IVT) dose of Vancomycin. Cerebrospinal fluid (CSF) samples were analysed and pharmacokinetic parameters: elimination rate constant (ke) and distribution volume (Vd) were calculated in order to adjust the dose. Mean values of Vd and elimination half-life for these patients were 244 (± 162) mL and 37.1 (±23.3) hours respectively. A great variability in the Vd was observed in some patients. This change in Vd correlates with problems in the ventricle size or with septated ventricles. In all cases a new dose was suggested according to the calculated parameters. Due to variations in the system throughout therapy, a protocol for CSF samples collection was proposed in order to individualise Vancomycin dosage according to pharmacokinetic parameters