José Gameiro dos Santos

Electrochemical Characteristics of Crystalline and Amorphous SnS2 in Lithium Cells

Amorphous (w) and crystalline (h) SnS{sub 2} have been used as active cathode materials in nonaqueous lithium cells. The discharge and charge-discharge cycling properties were galvanostatically measured at different current densities from 0.1 to 1 mA/cm{sup 2}. The w-SnS{sub 2} phase exhibited superior electrochemical characteristics to those of h-SnS{sub 2} phase, as evidenced by the higher Li ion diffusion coefficient, higher specific capacity and energy and better cycling properties. The Li/w-SnS{sub 2} cell can deliver up to 614 Ah/kg and 1,100 Wh/kg at a potential around 1 V when it is discharged at 0.1 mA/cm{sup 2} current density. These capacity and energy density values clearly exceeded those of other lithium batteries made of different amorphous transition metal sulfides.

The Kinetic Profile of Gentamicin in Premature Neonates

The kinetic profile of gentamicin in premature infants has been studied to enable the development of optimized dosage schedules for neonatal intensive‐care units and to stress the relationship between the pharmacokinetic parameters and several demographic, developmental and clinical factors which might be associated with changes in gentamicin disposition.

Predictive capacity of carbamazepine pharmacokinetic parameters in a Portuguese outpatient population

The individualization of anticonvulsant therapy regimens can contribute to the implementation of appropriate carbamazepine (CBZ) maintenance doses in epileptic patients. An accurate method for the prediction of concentrations based on a determination of parameters and serum concentrations could be of clinical relevance in the management of epilepsy. In this study, we retrospectively evaluated the predictive performance in an adult outpatient population of six different methods, representing six sets of CBZ pharmacokinetic parameters selected according to the literature using a Bayesian computer program (PKS System; Abbott Laboratories, Abbott Park, IL, USA). The study involved 50 patients with two or more available concentrations selected under several inclusion criteria. The patients were taking CBZ (between 200 and 1600 mg/d) in monotherapy or polytherapy regimens and had no hepatic or renal disease. Steady state concentrations were predicted according to the use of prior information and using one and two feedback patient concentrations. Accuracy and precision were assessed by mean prediction error (ME), mean squared prediction error (MSE) and root mean squared prediction error (RMSE). The analysis showed CL = 0.067 L/hour/kg and Vd = 1.19 L/kg as the most accurate and precise set of pharmacokinetic parameters, presenting the highest percentage of clinically acceptable estimates (error < 2 microg/mL). Additionally, predictions based on one measured feedback concentration were found to be more accurate and precise than prior population-based predictions; the use of two previous patient concentrations further improved predictive capacity but failed to show a significant difference when compared with predictions based on one measured feedback concentration. In conclusion, the adoption of the previously mentioned set of parameters as population estimates and the use of at least one feedback concentration through the Bayesian approach seems to be essential for a better CBZ use in clinical practice. Finally, despite the obtained results, we believe that the Portuguese pharmacokinetic parameter determination of antiepileptics should be carried out to improve the rationale and cost-effectiveness of anticonvulsant therapy.

Endoscopic management of sinonasal hemangiopericytoma: case report and literature review

Introduction: Hemangiopericytoma is a rare vascular tumor of the sinonasal region, associated with epistaxis and nasal obstruction as the main symptoms. When located in this region, it has special clinical characteristics that differentiate it from others. Case presentation: The following paper reports the case of a 43-year-old female patient presenting with right nasal obstruction and 6 months of evolution associated with mucopurulent rhinorrhea and recurrent right side epistaxis. Physical examination showed a right obstructive mass originating from the cribriform plate. Computed tomography of the paranasal sinuses revealed a complete blockage of the right nasal cavity by a homogeneous content, with soft tissue density and no evident contrast enhancement. The lesion extended superiorly to the cribriform plate but without intracranial or orbital extension. The patient was treated with endoscopic surgery and anatomopathological study revealed sinonasal hemangiopericytoma. The patient had complete remission and subsequent 3-year follow-up without recurrence. Conclusion: The recommended treatment for hemangiopericytoma is total surgical excision with free margins. The results are generally good and the risk of recurrence seems to be associated with incomplete tumor excision. A literature review is presented and its main characteristics are discussed.

On ciprofloxacin concentration in chronic rhinosinusitis

OBJECTIVE Considering that all the evidence indicates that chronic rhinosinusitis without nasal polyps (CRSsNP) and chronic rhinosinusitis with nasal polyps (CRSwNP) are distinct entities, the aim of this study was to compare the concentrations obtained in plasma and in sinonasal mucosa with oral and nasal topical ciprofloxacin, in patients with and without nasal polyps, without evaluating the effectiveness of the use of an antibiotic. METHODS Prospective clinical study with single-blind randomization. The population consisted of patients with chronic rhinosinusitis with eligible for endonasal surgery, over 18 years old. It took place between January 2010 and December 2014. A single preoperative dose of ciprofloxacin (oral or nasal topic- spray, gel or drops) was given and samples of plasma and nasal mucosa (inferior turbinate, middle turbinate, ethmoid and maxillary sinus) were collected prior to surgery. The plasma and mucosal ciprofloxacin concentrations were assayed with high performance liquid chromatography (HPLC) with fluorescence detection (FD). RESULTS The oral ciprofloxacin achieved better mucosal concentrations but had a significant plasmatic expression in all patients. None of the topical formulations achieved measurable ciprofloxacin plasmatic levels. Among the topical formulations, the gel had the best mucosal results, despite the existence of polyposis.