Extended-interval gentamicin administration in neonates: a simplified approach.

OBJECTIVE: Gentamicin dosing is highly variable and remains complicated in the neonatal population. Traditional dosing in our unit resulted in an excessive number of elevated trough serum gentamicin levels. We hypothesized that one uniform gentamicin dose for neonates of all gestational ages will reduce the incidence of elevated trough levels from 50 to 10%. STUDY DESIGN: Our prospective, randomized, controlled trial enrolled eligible neonates into two groups, according to gestational age (⩽34 6/7 (group I) and >35 0/7 weeks (group II)). Patients in the study arm received a dose of gentamicin 5 mg kg(-1) intravenous (i.v.) every 36 h, whereas patients in the control arm received traditional dosage. Patients were monitored for resolution of infection, serum gentamicin levels and adverse effects. We confirmed our findings in a follow-up study. Fisher's exact and Mann-Whitney tests were used for statistical analysis. RESULTS: We enrolled 96 neonates, 50 in group I (n=25 per arm) and 46 in group II (n=23 per arm). Elevated trough levels were reduced by 66% in group I (P=0.61) and 100% in group II (P=0.0015). In the study arm of both groups, 48/49 neonates had Cmin serum gentamicin concentration (SGC) <2 mg l(-1) and the majority had a trough SGC <1 mg l(-1) (P<0.0001). The study dose resulted in maximum gentamicin levels in the goal range and a 50% reduction in dosage modifications. There were no treatment failures or adverse effects. Our follow-up study phase confirmed these results. CONCLUSION: A standardized gentamicin dosage of 5 mg kg(-1) i.v. every 36 h to neonates of all gestational ages was safe and resulted in SGCs in goal therapeutic ranges. The implications of this simplified gentamicin dosage are to reduce health-care costs by less frequent dosing of gentamicin and reducing medication errors in physician prescribing from complicated dosing schemes.

Prospective analysis of 61 cases of enteroviral meningitis: interest of systematic genome detection in cerebrospinal fluid irrespective of cytologic examination results.

BACKGROUND: Enteroviruses are the most commonly identified cause of viral meningitis. Detection of the enterovirus genome in cerebrospinal fluid (CSF) using reverse-transcription polymerase chain reaction (PCR) has proved to be useful in diagnosis and is more rapid and sensitive than viral cultures. In routine practice, cytologic examination results of CSF are obtained swiftly and PCR indication is performed as a second step. OBJECTIVES: The aim of this study was to determine, by analysis of complete data from CSF results for 61 cases of proven enteroviral meningitis, whether cytologic CSF findings can be used to establish viral etiology and to indicate if PCR assay should be performed. STUDY DESIGN: From a prospective study of children admitted during 1997 for suspected enterovirus meningitis in which PCR and viral cultures of CSF were systematically performed, we selected 61 patients with proven enterovirus meningitis. We compared global white cell count (WCC), relative percentage of lymphocytes/neutrophils, PCR and culture for enterovirus, patient age, and clinical data. RESULTS: 92% of patients (56/61) had positive PCR in CSF and in 48% (29/61) enterovirus was isolated in CSF. Nine patients (14.75%) had WCC<10/mm(3); eight of them had positive PCR and two had positive culture. There were comparable numbers of CSF with a predominance of lymphocytes (n=25) and CSF with a predominance of neutrophils (n=22), and of positive PCR and positive cultures of CSF in the two groups. Results were not influenced by the age of the patients. CONCLUSION: Irrespective of other CSF parameters, it seems difficult to dispense with PCR assay for enterovirus genome detection. It should be introduced as a true rapid routine test. Early reporting of a positive PCR result could result in a considerable saving in health resources.

[Single extramedullary plasmacytoma of the nose]. / Plasmocitoma solitario extramedular de localización nasal.

A new solitary extramedullary plasmacytoma of nasal localization meeting the conditions for definition is reported. The patient was treated with surgery and irradiation, which controlled the disease and produced excellent cosmetic results. The bibliography is reviewed and the pathologic, clinical, and evolutive characteristics are discussed.

Post-depositional fracturing and subsidence of pumice flow deposits: Lascar Volcano, Chile.

Unconsolidated pyroclastic flow deposits of the 1993 eruption of Lascar Volcano, Chile, have, with time, become increasingly dissected by a network of deeply penetrating fractures. The fracture network comprises orthogonal sets of decimeter-wide linear voids that form a pseudo-polygonal grid visible on the deposit surface. In this work, we combine shallow surface geophysical imaging tools with remote sensing observations and direct field measurements of the deposit to investigate these fractures and their underlying causal mechanisms. Based on ground penetrating radar images, the fractures are observed to have propagated to depths of up to 10 m. In addition, orbiting radar interferometry shows that deposit subsidence of up to 1 cm/year-1 occurred between 1993 and 1996 with continued subsidence occurring at a slower rate thereafter. In situ measurements show that 1 m below the surface, the 1993 deposits remain 5°C to 15°C hotter, 18 years after emplacement, than adjacent deposits. Based on the observed subsidence as well as estimated cooling rates, the fractures are inferred to be the combined result of deaeration, thermal contraction, and sedimentary compaction in the months to years following deposition. Significant environmental factors, including regional earthquakes in 1995 and 2007, accelerated settling at punctuated moments in time. The spatially variable fracture pattern relates to surface slope and lithofacies variations as well as substrate lithology. Similar fractures have been reported in other ignimbrites but are generally exposed only in cross section and are often attributed to formation by external forces. Here we suggest that such interpretations should be invoked with caution, and deformation including post-emplacement subsidence and fracturing of loosely packed ash-rich deposits in the months to years post-emplacement is a process inherent in the settling of pyroclastic material.