Development and validation of liquid chromatography-tandem mass spectrometry method to quantify dasatinib in plasma and its application to a pharmacokinetic study

Abstract Dasatinib, a potent oral multi-targeted kinase inhibitor against Src and Bcr-Abl, can decrease inflammatory response in sepsis. A simple and cost-effective method for determination of an effective dose dasatinib was established. This method was validated in human plasma, with the aim of reducing the number of animals used, thus, avoiding ethical problems. Dasatinib and internal standard lopinavir were extracted from 180 uL of plasma using liquid-liquid extraction with methyl tert-butil ether, followed by liquid chromatography coupled to triple quadrupole mass spectrometry in multiple reaction monitoring mode. For the pharmacokinetic study, 1 mg/kg of dasatinib was administered to mice with and without sepsis. The method was linear over the concentration range of 1-98 ng/mL for DAS in mice and human plasma, with r2>0.99 and presented intra- and interday precision within the range of 2.3 - 6.2 and 4.3 - 7.0%, respectively. Further intra- and interday accuracy was within the range of 88.2 - 105.8 and 90.6 - 101.7%, respectively. The mice with sepsis showed AUC0-t = 2076.06 h*ng/mL and Cmax =102.73 ng/mL and mice without sepsis presented AUC0-t = 2128.46 h*ng/mL. Cmax = 164.5 ng/mL. The described analytical method was successfully employed in pharmacokinetic study of DAS in mice.

Assessing the contribution of UGT isoforms on raltegravir drug disposition through PBPK modeling.

This work aimed to develop a physiologically based pharmacokinetic (PBPK) model for raltegravir accounting for UDP-glucuronosyltransferase (UGT) metabolism to assess the effect of UGT gene polymorphisms. Raltegravir elimination was evaluated using Km and Vmax values from human recombinant systems and UGT tissue scalar considering liver, kidney, and intestine. The predicted/observed ratios for raltegravir PK parameters were within a 2-fold error range in UGT1A1 poor and normal metabolizers, except in Asian UGT1A1 poor metabolizers. This PBPK modeling approach suggests that UGT1A3 is the main contributor to raltegravir's metabolism. UGT1A3 and UGT1A1 gene polymorphisms might have an additive effect on raltegravir's drug disposition and response. The final model accounting for hepatic, renal, and intestinal UGT metabolism, biliary clearance, and renal excretion improved model predictions compared with the previously published models. This PBPK model with the quantitative characterization of raltegravir elimination pathways can support dose adjustments in different clinical scenarios.

Vertebroplasty in bone fragility fractures and tumor fractures: risks and benefits / Vertebroplastia em fraturas por fragilidade óssea e tumorais: riscos e benefícios / Vertebroplastia en fracturas por fragilidad ósea y tumorales: riesgos y beneficios

ABSTRACT Objective: To evaluate the results of percutaneous vertebroplasty (PV) in spinal fragility fractures (osteoporosis/tumor), analyzing possible complications. Method: We evaluated 33 patients with spinal fractures (FXV) due to osteoporosis or tumor who underwent PV between January and November 2021. A physical examination was performed, obtaining the history and risk factors for bone fragility/tumor and a radiological evaluation of the spine to verify FXV. Genant's semiquantitative method was used for postoperative classification, the VAS score, and a disability questionnaire (ODI). A radiologist evaluated tomographic control to quantify vertebral filling and extravasation, determining where they occurred. Results: 46 vertebrae of 33 patients were operated on, with a mean age of 71 years, and 11 patients with more than one level of surgery. Of the total, 13 patients had tumor fractures, and 20 had fractures due to insufficiency. PMMA extravasation was observed in 31 vertebrae, most frequently in the External Vertebral Venous Plexus (23), Discal Body (9), Anterior Epidural Recess (4), Pulmonary Vessels (4), Internal Vertebral Venous Plexus (3), Inferior Cava (2), Adipose Plane (2) and Azygos Vein (1). No patient had clinical complications. Furthermore, the mean preoperative VAS was eight, the postoperative one was 3, the mean preoperative ODI was 56, and the postoperative one was 30. Conclusion: PMMA extravasation was frequent in several locations and levels without any clinical complications. VP proved to be effective in improving pain and function. Level III; Longitudinal Retrospective Cohort Study.

RESUMO Objetivo: Avaliar os resultados da vertebroplastia percutânea (VP) em fraturas por fragilidade da coluna (osteoporose/tumoral), analisando possíveis complicações. Método: Foram avaliados 33 pacientes com fratura da coluna vertebral (FXV) por osteoporose ou tumor, entre janeiro e novembro de 2021, submetidos à VP. Foi realizado exame físico junto à obtenção da história e fatores de risco para fragilidade óssea / tumor, além de avaliação radiológica da coluna para constatação de FXV. O método semiquantitativo de Genant foi empregado para a classificação no pós-operatório, além do score EVA e do questionário de incapacidade (ODI). O controle tomográfico foi avaliado por médico radiologista para quantificação do preenchimento vertebral e extravasamento, determinando para onde ocorreram. Resultados: Foram operadas 46 vértebras de 33 pacientes, como média de idade de 71 anos, sendo 11 pacientes com mais de um nível operado. Do total, 13 pacientes apresentavam fraturas tumorais e 20 possuíam fraturas por insuficiência. Observou-se extravasamento do PMMA em 31 vértebras, mais frequentemente para Plexo Venoso Vertebral Externo (23), Corpo Discal (9), Recesso Epidural Anterior (4) Vasos Pulmonares (4), Plexo Venoso Vertebral Interno (3), Cava Inferior (2), Plano Adiposo (2) e Veia Ázigos (1). Nenhum paciente apresentou complicações clínicas. Ainda, o EVA pré-operatório médio foi 8 e o pós-operatório de 3, enquanto o ODI pré-operatório médio foi de 56 e o pós-operatório de 30. Conclusão: O extravasamento de PMMA foi frequente em diversos locais e níveis, sem nenhuma complicação clínica. A VP mostrou-se eficaz na melhora de dor e função. Nível III; Estudo Longitudinal Coorte Retrospectivo.

RESUMEN Objetivo: Evaluar los resultados de la vertebroplastia percutánea (PV) en fracturas por fragilidad de columna (osteoporosis/tumor), analizando posibles complicaciones. Método: Se evaluaron 33 pacientes con fractura de columna (FXV) por osteoporosis o tumor, entre enero y noviembre de 2021, que fueron sometidos a PV. Se realizó examen físico junto con obtención de antecedentes y factores de riesgo de fragilidad ósea/tumor, además de evaluación radiológica de columna para verificar FXV. Para la clasificación postoperatoria se utilizó el método semicuantitativo de Genant, además de utilizar la escala EVA y un cuestionario de discapacidad (ODI). El control tomográfico fue evaluado por un radiólogo para cuantificar el llenado vertebral y la extravasación, determinando dónde se producían. Resultados: Se operaron 46 vértebras de 33 pacientes, con una edad promedio de 71 años, 11 pacientes con más de un nivel de cirugía. Del total, 13 pacientes presentaron fracturas tumorales y 20 fracturas por insuficiencia. Se observó extravasación de PMMA en 31 vértebras, con mayor frecuencia en el Plexo Venoso Vertebral Externo (23), Cuerpo Discal (9), Receso Epidural Anterior (4), Vasos Pulmonares (4), Plexo Venoso Vertebral Interno (3), Cava Inferior (2), Plano Adiposo (2) y Vena Azygos (1). Ningún paciente presentó complicaciones clínicas. Además, la EVA preoperatoria media fue de 8 y la postoperatoria de 3, mientras que la ODI preoperatoria media fue de 56 y la postoperatoria de 30. Conclusión: La extravasación de PMMA fue frecuente en varias localizaciones y niveles, sin complicaciones clínicas. VP demostró ser eficaz para mejorar el dolor y la función. Nivel III; Estudio de cohorte retrospectivo longitudinal.

Extended stability study of an extemporaneously analgesic solution of clonidine, ropivacaine and fentanyl

Abstract The aim of this work was to perform an extended stability study for the analgesic containing fentanyl, clonidine and ropivacaine in physiological saline solution 0.9% at different infusion sites, such as infusion bags, epidural infusion sets and syringes. The extended stability was assessed by an HPLC system equipped with a photodiode array detector set at 210 nm. The separation was conducted on a C18 column maintained at 40˚C and using an isocratic mobile phase consisted of buffer solution-methanol-acetonitrile (45:45:10, v/v/v). The presence of particulate matter and the pH of each solution were also investigated. Twenty-four hours after the preparation, the formation of one suspected product was observed and for all drugs, in 24 hours it was observed the concentration decrease in different sets (PVC infusion bags, syringes and epidural infusion administration sets). The pH values of each solution varied no more than 5% during the study and no particle was observed. Conclusion: The extended stability study was applied to the analgesic solution and promoted the detection of an unexpected peak in 24 hours. Based on it, further stability studies are necessary to determine the extended stability data.

Does decubitus affect neural elements positioning? a mri study comparing dorsal and lateral position / O decúbito afeta a posição dos elementos neurais? estudo de ressonância magnética comparando a posição dorsal e lateral / ¿la posición afecta el posicionamiento de los elementos neurales? un estudio de rm que compara la posición dorsal y lateral

ABSTRACT Objective To evaluate the displacement of nerve structures according to the decubitus position of the patient in a magnetic resonance imaging (MRI) study. Methods MRI was performed at a radiology clinic in 20 patients in dorsal and right lateral decubitus. The measurement considered was the shortest distance between the dura mater and the medial wall of the pedicle. Results The largest measurement was 11.6 mm in left lateral decubitus, 12.2 mm in right lateral decubitus, 10.5 mm in right dorsal decubitus, and 9.2 mm in left dorsal decubitus. In some patients the space between the medial wall of the pedicle and the dura mater was larger when in lateral decubitus, while in others when in dorsal decubitus. The mean displacement of the measurements on the left was 1.14 mm and on the right 1.355 mm. Conclusions The structures moved on average little more than 1 mm in the positions studied. The positioning of the patient for surgery does not change the space to be approached, being the surgeon's choice according to his learning curve. Level of evidence II; Prospective study of lower quality.

RESUMO Objetivo Avaliar o deslocamento das estruturas nervosas conforme o decúbito do paciente em um estudo de Ressonância Nuclear Magnética (RNM). Métodos Foram realizadas RNM em 20 pacientes em uma clínica de radiologia em decúbito dorsal e lateral direito. A medida considerada será a menor distância entre a dura-máter e a parede medial do pedículo. Resultados A maior medida em decúbito lateral esquerdo foi 11,6 mm, em decúbito lateral direito foi 12,2 mm, em decúbito dorsal direito foi 10,5 mm e no esquerdo, 9,2 mm. O espaço entre a parede medial do pedículo é maior em decúbito lateral em alguns pacientes e, em outros, em decúbito dorsal. O deslocamento médio das medidas à esquerda foi 1,14 mm e à direita 1,355 mm. Conclusões As estruturas se deslocaram, em média, pouco mais de 1 mm nas posições estudadas. O posicionamento do paciente na cirurgia não muda o espaço a ser abordado, sendo de escolha do cirurgião, conforme a sua curva de aprendizado. Nível de evidência II; Estudo prospectivo de menor qualidade .

RESUMEN Objetivo Evaluar el desplazamiento de las estructuras nerviosas conforme al decúbito del paciente en un estudio de Resonancia Nuclear Magnética (RNM). Métodos Fueron realizadas RNM en 20 pacientes en una clínica de radiología en decúbito dorsal y lateral derecho. La medida considerada será la menor distancia entre la duramadre y la pared medial del pedículo. Resultados La mayor medida en decúbito lateral izquierdo fue 11,6 mm, en decúbito lateral derecho fue 12,2 mm, en decúbito dorsal derecho fue 10,5 mm y en el izquierdo, 9,2 mm. El espacio entre la pared medial del pedículo es mayor en decúbito lateral en algunos pacientes y, en otros, en decúbito dorsal. El desplazamiento promedio de las medidas a la izquierda fue 1,14 mm y a la derecha de 1,355 mm. Conclusiones Las estructuras se desplazaron, en promedio, poco más de 1 mm en las posiciones estudiadas. El posicionamiento del paciente en la cirugía no cambia el espacio a ser abordado, siendo la elección del cirujano conforme a su curva de aprendizaje. Nivel de evidencia II; Estudio prospectivo de menor calidad.

Pretreatment and non-specific binding in ultrafiltration device: Impact on protease inhibitor quantification.

INTRODUCTION: Ultrafiltration (UF) is used to separate unbound drugs; however, non-specific binding (NSB) may be a limiting factor of this technique. Pretreatment of UF devices has been suggested to reduce NSB. Therefore, the pretreatment methodologies for UF devices were evaluated in order to test their effectiveness in reducing NSB of protease inhibitors (PIs). METHODOLOGY: Two PIs (lopinavir-LPV and ritonavir-RTV) were tested. UF devices were pretreated with ultrapure water, Tween-20 or Tween-80. To evaluate the NSB, after UF devices being pretreated, ultrafiltrate solutions containing the analytes at two concentrations (low and high) were used. Samples were quantified by LC-MS/MS. RESULTS: UF devices pretreated with Tween-5% had the lowest NSB for both analytes. NSB values varied between 7 and 11% at low concentration 16-34% at high LPV concentration, respectively. For RTV, NSB was approximately 6% for low concentration and 18% for high concentration. Failure to completely remove Tween in UF devices could results in an overestimation of NSB. CONCLUSION: Pretreatment of UF device with Tween and subsequent removal proved to be effective in reducing NSB of PI.

Relationship of anti-tuberculosis drug-induced liver injury and genetic polymorphisms in CYP2E1 and GST

ABSTRACT Setting: Treatment of tuberculosis (TB) can result in Drug-Induced Liver Injury (DILI) since hepatotoxic metabolites are formed during the biotransformation of isoniazid (INH).DILI can be related to the genetic profile of the patient. Single nucleotide polymorphisms in the CYP2E1 gene and GSTM1 and GSTT1 deletion polymorphisms have been associated with adverse events caused by INH. Objective: To characterize the genetic polymorphisms of CYP2E1, GSTT1 and GSTM1 in TB carriers. Design: This is an observational prospective cohort study of 45 patients undergoing treatment of TB. PCR-RFLP and multiplex-PCR were used. Results: The distribution of genotypic frequency in the promoter region (CYP2E1 gene) was: 98% wild genotype and 2% heterozygous. Intronic region: 78% wild genotype; 20% heterozygous and 2% homozygous variant. GST enzyme genes: 24% Null GSTM1 and 22% Null GSTT1. Patients with any variant allele of the CYP2E1 gene were grouped in the statistical analyses. Conclusion: Patients with the CYP2E1 variant genotype or Null GSTT1 showed higher risk of presenting DILI (p = 0.09; OR: 4.57; 95% CI: 0.75-27.6). Individuals with both genotypes had no increased risk compared to individuals with one genotype.

Relationship of anti-tuberculosis drug-induced liver injury and genetic polymorphisms in CYP2E1 and GST.

SETTING: Treatment of tuberculosis (TB) can result in Drug-Induced Liver Injury (DILI) since hepatotoxic metabolites are formed during the biotransformation of isoniazid (INH). DILI can be related to the genetic profile of the patient. Single nucleotide polymorphisms in the CYP2E1 gene and GSTM1 and GSTT1 deletion polymorphisms have been associated with adverse events caused by INH. OBJECTIVE: To characterize the genetic polymorphisms of CYP2E1, GSTT1 and GSTM1 in TB carriers. DESIGN: This is an observational prospective cohort study of 45 patients undergoing treatment of TB. PCR-RFLP and multiplex-PCR were used. RESULTS: The distribution of genotypic frequency in the promoter region (CYP2E1 gene) was: 98% wild genotype and 2% heterozygous. Intronic region: 78% wild genotype; 20% heterozygous and 2% homozygous variant. GST enzyme genes: 24% Null GSTM1 and 22% Null GSTT1. Patients with any variant allele of the CYP2E1 gene were grouped in the statistical analyses. CONCLUSION: Patients with the CYP2E1 variant genotype or Null GSTT1 showed higher risk of presenting DILI (p=0.09; OR: 4.57; 95% CI: 0.75-27.6). Individuals with both genotypes had no increased risk compared to individuals with one genotype.

A novel and simple LC-MS/MS quantitative method for dextromethorphan and dextrorphan in oral fluid.

Aim: To develop and validate a simple method using LC-MS/MS for determination of dextromethorphan (DXM) and dextrorphan (DT) in human oral fluid. Results: Following protein precipitation, chromatographic separation used a phenyl column with isocratic elution (1 ml/min) of 10 mM ammonium-formate buffer and acetonitrile (65:35; v/v) with 0.1% formic acid. Retention times were 2.6 min for DT and 5 min for DXM. Total run time was 7 min. The intra- and inter-assay deviations (accuracy) for DT (1-100 ng/ml) and DXM (5-1000 ng/ml) ranged from -13.6 to 8.8% and -9.6 to 5.7%, respectively. Precision variations were ≤7.5%. Matrix effect was ≤11.8%. Conclusion: This method may prove helpful for quantification of DT and DXM in oral fluid for either clinical or toxicological purposes.

A Rapid and Simple HPLC Method for Therapeutic Monitoring of Vancomycin.

Therapeutic monitoring of the antibiotic vancomycin is important to achieve specific plasma concentration and prevent toxic effects. Several assays have been described for vancomycin determination in clinical practice, but high-performance liquid chromatography is still considered the gold standard for the quantification of vancomycin. In this study, we developed a new and rapid high-performance liquid chromatography method requiring 50 µL of plasma for the quantification of vancomycin. Acetonitrile was used for processing plasma by protein precipitation (1:2.5). Isocratic chromatographic analysis was carried out on a C18 silica-based (2.7 µm) column with the mobile phase containing 20 mM ammonium acetate/formic acid buffer (pH 4.0):methanol 88:12 (v/v). A diode array detector was used for UV detection at 240 nm. This method was validated according to the Brazilian Health Surveillance Agency legislation and International Conference on Harmonization guidelines. The measurement range was 1-100 µg/mL, analysis time was 8 min, and intermediate precision was <12%, supporting the present method as a fast, simple, and effective alternative for therapeutic monitoring of vancomycin.

Randomized clinical trial comparing the pharmacokinetics of standard- and increased-dosage lopinavir-ritonavir coformulation tablets in HIV-positive pregnant women.

A lopinavir-ritonavir (LPV/r)-based regimen is recommended during pregnancy to reduce the risk of HIV mother-to-child transmission, but the appropriate dose is controversial. We compared the pharmacokinetics of standard and increased LPV/r doses during pregnancy. This randomized, open-label prospective study enrolled 60 pregnant women between gestational weeks 14 and 30. The participants received either the standard dose (400/100 mg twice a day [BID]) or increased dose (600/150 mg BID) of LPV/r tablets during pregnancy and the standard dose for 6 weeks after childbirth. Pharmacokinetics analysis was performed using a high-performance liquid chromatography-tandem mass spectrometry method. Adherent participants who received the standard dose presented minimum LPV concentrations of 4.4, 4.3, and 6.1 µg/ml in the second and third trimesters and postpartum, respectively. The increased-dose group exhibited values of 7.9, 6.9, and 9.2 µg/ml at the same three time points. Although LPV exposure was significantly higher in the increased-dose group, the standard dose produced therapeutic levels of LPV against wild-type virus in all adherent participants, except one patient in the third trimester; 50%, 37.5%, and 25%, and 0%, 15%, and 0% of the participants in the standard- and increased-dose groups failed to achieve therapeutic levels against resistant viruses during the second and third trimesters and after childbirth, respectively. After 12 weeks of treatment and after childbirth, all adherent participants achieved undetectable HIV viral loads, and their babies (49/54) were uninfected. No serious drug-related adverse events were observed. We conclude that the standard dose is appropriate for use during pregnancy and that an increased dose may be necessary for women harboring resistant HIV. (This study has been registered at ClinicalTrials.gov under registration no. NCT00605098.).

Assessment of the relative dose-response test as indicators of hepatic vitamin A stores in various stages of chronic liver disease.

Hepatic vitamin A stores should be the best early indicator of vitamin A status because more than 90% of total body vitamin A is stored in the liver. The objective of the present study was to evaluate the hepatic vitamin A stores in all stages of chronic liver disease (CLD), including chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). One hundred forty-four patients (age 55.34 ± 9.38 years) were evaluated in a cross-sectional study. Vitamin A nutrition status was analyzed by serum retinol levels and relative dose-response (RDR) method. Patients with cholestasis were excluded from the sample group. Biochemical, clinical, and anthropometric evaluations were performed. Vitamin A deficiency (VAD) was detected in 51.4% of all patients. Patients with adequate levels of serum retinol presented adequate liver vitamin A reserves; in contrast, nearly half the patients with low serum retinol levels presented adequate levels of retinol in the liver, although none of the patients with hepatitis had this condition. Therefore, the effectiveness of the RDR method for evaluating vitamin A nutrition status was limited in patients with cirrhosis and HCC, perhaps due to the advanced age of these patients, since those in the chronic hepatitis group, who were younger, responded adequately to the test. Thus, the RDR method should be modified when applied to later stages of CLD, considering the time and dose of retinyl palmitate supplementation, as VAD may be a risk factor for the progression of the disease.

Analysis of angiogenic factors and cyclooxygenase-2 expression in cartilaginous tumors- clinical and histological correlation.

OBJECTIVES: To study the role of angiogenesis and cyclooxygenase-2 expression in cartilaginous tumors and correlate these factors with prognosis. INTRODUCTION: For chondrosarcoma, the histological grade is the current standard for predicting tumor outcome. However, a low-grade chondrosarcoma can follow an aggressive course-as monitored by sequential imaging techniques-even when it is histologically indistinguishable from an enchondroma. Therefore, additional tools are needed to help identify the biological potential of these tumors. The degree of angiogenesis that is induced by the tumor could assist in this task. Angiogenesis can be quantified by measuring the expression of vascular endothelial growth factor and CD34, and cyclooxygenase-2 can induce angiogenesis by stimulating the production of proangiogenic factors. METHODS: In total, 21 enchondromas and 58 conventional chondrosarcomas were studied by examining the clinical and histopathological findings in conjunction with the immunostaining markers of angiogenesis and cyclooxygenase- 2 expression. RESULTS: The significant variables that were associated with poor outcome were 1) higher-grade chondrosarcomas, 2) tumors that developed in flat bones, and 3) over-expression of CD34 (with a median count that was higher than 5.9 vessels in 5 high power fields). Moreover, CD34 expression (measured using the Chalkley method) revealed significantly higher microvessel density in flat bone chondrosarcomas. DISCUSSION: Previous studies have shown a positive correlation between Chalkley microvessel density and histological grade; however, in our sample, we found that the former is predictive of the outcome. Chondrosarcomas in flat bones have been shown to correlate with a poor prognosis. We also found that CD34 microvessel density values were significantly higher in flat-bone chondrosarcomas. This could explain-at least in part-the more aggressive biological course that is taken by these tumors. CONCLUSIONS: These results provide evidence that CD34 microvessel density in chondrosarcomas can be helpful in predicting patient outcome and may add to our understanding of chondrosarcoma pathogenesis.

Analysis of angiogenic factors and cyclooxygenase-2 expression in cartilaginous tumors: clinical and histological correlation

OBJECTIVES: To study the role of angiogenesis and cyclooxygenase-2 expression in cartilaginous tumors and correlate these factors with prognosis. INTRODUCTION: For chondrosarcoma, the histological grade is the current standard for predicting tumor outcome. However, a low-grade chondrosarcoma can follow an aggressive course-as monitored by sequential imaging techniques-even when it is histologically indistinguishable from an enchondroma. Therefore, additional tools are needed to help identify the biological potential of these tumors. The degree of angiogenesis that is induced by the tumor could assist in this task. Angiogenesis can be quantified by measuring the expression of vascular endothelial growth factor and CD34, and cyclooxygenase-2 can induce angiogenesis by stimulating the production of proangiogenic factors. METHODS: In total, 21 enchondromas and 58 conventional chondrosarcomas were studied by examining the clinical and histopathological findings in conjunction with the immunostaining markers of angiogenesis and cyclooxygenase- 2 expression. RESULTS: The significant variables that were associated with poor outcome were 1) higher-grade chondrosarcomas, 2) tumors that developed in flat bones, and 3) over-expression of CD34 (with a median count that was higher than 5.9 vessels in 5 high power fields). Moreover, CD34 expression (measured using the Chalkley method) revealed significantly higher microvessel density in flat bone chondrosarcomas. DISCUSSION: Previous studies have shown a positive correlation between Chalkley microvessel density and histological grade; however, in our sample, we found that the former is predictive of the outcome. Chondrosarcomas in flat bones have been shown to correlate with a poor prognosis. We also found that CD34 microvessel density values were significantly higher in flat-bone chondrosarcomas. This could explain-at least in part-the more aggressive biological course that is taken by these tumors. CONCLUSIONS: These results provide evidence that CD34 microvessel density in chondrosarcomas can be helpful in predicting patient outcome and may add to our understanding of chondrosarcoma pathogenesis.

Uso da câmara de ar em cirurgia ortopédica: aplicações, vantagens e desvantagens / Uso de la cámara de aire en cirugía ortopédica: aplicaciones, ventajas y desventajas / The use of inner tube in orthopaedic surgery: applications, advantages and disadvantages

OBJETIVO: o trabalho visou à difundir o uso da câmara de ar, de forma sistemática, em cirurgias ortopédicas, como suporte e protetor das saliências ósseas, em especial nas cirurgias de longa duração. MÉTODOS: trata-se de um estudo prospectivo não randomizado, realizado entre 2002 e 2007, totalizando de 264 procedimentos ortopédicos. RESULTADOS: verificou-se que, independente do tempo de cirurgia, não houve áreas de pressão nas proeminências ósseas ou lesões de nervos periféricos no pós-operatório. CONCLUSÃO: os resultados do presente estudo permitiram recomendar a câmara de ar como uma excelente opção de suporte em cirurgias ortopédicas, pois se trata de um dispositivo de baixo custo, fácil obtenção e alta reprodutibilidade.

OBJECTIVE: this paper aimed at promoting the use of the inner tube as a systematic device in orthopedic surgery, such as body holder and protector of bony projections, especially in long-term spine surgeries. METHODS: this was a prospective non-randomized study, carried out from 2002 to 2007, with 264 orthopedic procedures. RESULTS: we found that, regardless the time of surgery, there were no areas of pressure around bony prominences or injury of peripheral nerves in the postoperative follow-up. CONCLUSION: those results could recommend the inner tube as an excellent option like a frame in orthopedic surgery. It is an inexpensive device, easy to obtain, and without known complications.

OBJETIVO: el trabajo tiene como objetivo difundir el uso de la cámara de aire de modo usual en cirugías ortopédicas, como el apoyo y la protección ósea de las proyecciones, en especial en la cirugía de larga duración. MÉTODOS: este es un estudio prospectivo, no aleatorizado, realizado durante 2002 a 2007 con un total de 264 procedimientos ortopédicos. RESULTADOS: fue encontrado que, independiente del momento de la cirugía, no hay zonas de presión sobre prominencias óseas o lesiones nerviosas periféricas en el postoperatorio. CONCLUSIÓN: los presentes resultados permiten recomendar el interior del tubo como una excelente opción para el apoyo en cirugía ortopédica, ya que es un dispositivo de bajo costo, fácil de obtener y de alta reproducibilidad.

Pharmacokinetic/pharmacodynamic modeling of psychomotor impairment induced by oral clonazepam in healthy volunteers.

This study was undertaken to model the relationship between clonazepam plasma concentrations and a central nervous system adverse effect (impairment of the psychomotor performance) following the oral administration of immediate-release tablets of clonazepam in healthy volunteers. Such a (P)pharmacokinetic/(P)pharmacodynamic (PK/PD) study is important to interpret properly the consequences of determined levels of plasma concentrations of psychoactive therapeutic drugs reported to be involved in road-traffic accidents. Twenty-three male subjects received a single oral dose of 4 mg clonazepam. Plasma concentration, determined by on-line solid phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry, and psychomotor performance, quantified through the Digit Symbol Substitution Test, were monitored for 72 hours. A 2-compartment open model with first order absorption and lag-time better fitted the plasma clonazepam concentrations. Clonazepam decreased the psychomotor performance by 72 +/- 3.7% (observed maximum effect), 1.5 to 4 hours (25th-75th percentile) after drug administration. A simultaneous population PK/PD model based on a sigmoid Emax model with time-dependent tolerance described well the time course of effect. Such acute tolerance could minimize the risk of accident as a result of impairment of motor skill after a single dose of clonazepam. However, an individual analysis of the data revealed a great interindividual variation in the relationship between clonazepam effect and plasma concentration, indicating that the phenomenon of acute tolerance can be predicted at a population, but not individual, level.

Resultado funcional em crianças e adolescentes submetidos à hemipelvectomia interna tipo II, com ou sem reconstrução do anel pélvico / Functional outcome in children and adolescents submitted to type II internal hemipelvectomy with or without reconstruction of the pelvic ring

Objetivo: Avaliar retrospectivamente os resultados funcionais em crianças e adolescentes portadores de tumores pélvicos, submetidos à hemipelvectomia interna tipo II, com ou sem reconstrução do anel pélvico. Métodos: Foram avaliados 31 pacientes portadores de tumor pélvico, tratados no Centro Infantil Boldrini e no Hospital A.C. Camargo, entre 1994 e 2005. O resultado funcional foi baseado no sistema de avaliação funcional padronizado por Enneking et al. Os critérios analisados foram: dor, função, aceitação emocional, necessidade de suporte, capacidade de deambulação e marcha. Dos 31 casos seguidos, 12 (38,7%) fizeram a reconstrução do anel pélvico com enxerto de fíbula e 19 (61,3%) não a fizeram. A média de idade dos pacientes foi de 11,4 anos (4-17,8 anos). A média de seguimento para os 31 casos foi de 41 meses. Resultado: Obtido aos 12 meses do pós-operatório, foi excelente em 17,4% dos pacientes (todos com reconstrução do anel pélvico), bom em 60,9% dos pacientes, regular em 17,4% e ruim em 4,3%. A média do escore foi melhor no grupo de pacientes com a reconstrução com auto-enxerto de fíbula, comparativamente ao grupo dos que não tiveram essa reconstrução, sendo significativa a diferença entre os grupos (p = 0,008). Conclusão: Os pacientes submetidos à hemipelvectomia interna com reconstrução do anel pélvico com auto-enxerto de fíbula tiveram melhor resultado funcional global comparativamente ao grupo dos que não foram submetidos à reconstrução (p = 0,007). Dentre os critérios específicos do sistema de avaliação funcional, os escores obtidos nos itens aceitação emocional (p = 0,001), capacidade de deambulação (p = 0,034) e marcha (p = 0,002) foram melhores nos pacientes com reconstrução, quando comparados com os do grupo sem reconstrução do anel pélvico...

Usefulness of serotoninergic challenge with oral citalopram.

OBJECTIVE: Challenge tests designed to evaluate serotoninergic pathways have widely used intravenous citalopram. Oral citalopram has also been used, but unsatisfactory results were obtained with a dose of 20 mg. The objective of this study was to determine whether a higher oral dose would reproduce similar to those described for intravenous administration. To that end, we evaluated cortisol, growth hormone and prolactin levels. METHOD: Eight healthy male volunteers were evaluated in a randomized crossover challenge test with 40 mg of oral citalopram or placebo. RESULTS: Cortisol levels increased at 2-4h after the oral citalopram intake, with a small amplitude peak occurring in two-thirds of the subjects. Levels of prolactin and growth hormone remained unchanged throughout the study. CONCLUSION: The use of oral citalopram might present an alternative in serotoninergic challenge tests, but higher doses are required.

Usefulness of serotoninergic challenge with oral citalopram / Utilidade do desafio serotoninérgico com citalopram oral

OBJECTIVE: Challenge tests designed to evaluate serotoninergic pathways have widely used intravenous citalopram. Oral citalopram has also been used, but unsatisfactory results were obtained with a dose of 20 mg. The objective of this study was to determine whether a higher oral dose would reproduce similar to those described for intravenous administration. To that end, we evaluated cortisol, growth hormone and prolactin levels. METHOD: Eight healthy male volunteers were evaluated in a randomized crossover challenge test with 40 mg of oral citalopram or placebo. RESULTS: Cortisol levels increased at 2-4h after the oral citalopram intake, with a small amplitude peak occurring in two-thirds of the subjects. Levels of prolactin and growth hormone remained unchanged throughout the study. CONCLUSION: The use of oral citalopram might present an alternative in serotoninergic challenge tests, but higher doses are required.

OBJETIVO: Testes-desafio desenvolvidos para avaliar as vias serotoninérgicas utilizaram amplamente citalopram intravenoso. Citalopram oral também foi utilizado, mas obtiveram-se resultados insatisfatórios com uma dose de 20 mg. O objetivo deste estudo foi o de determinar se uma dose oral mais elevada poderia reproduzir resultados similares aos descritos para administração intravenosa. Com esta finalidade, avaliamos os níveis de cortisol, de hormônio do crescimento e de prolactina. MÉTODO: Oito voluntários do sexo masculino saudáveis foram avaliados em um teste-desafio cruzado, aleatorizado, com 40 mg de citalopram oral ou placebo. RESULTADOS: Os níveis de cortisol aumentaram após 2-4 horas da ingestão de citalopram oral, com um pequeno pico de amplitude ocorrendo em dois terços dos indivíduos. Os níveis de prolactina e de hormônio de crescimento permaneceram inalterados ao longo do estudo. CONCLUSÃO: O uso de citalopram oral poderia apresentar uma alternativa em testes-desafio serotoninérgicos, mas doses maiores são necessárias.

On-line solid-phase extraction coupled with high-performance liquid chromatography and tandem mass spectrometry (SPE-HPLC-MS-MS) for quantification of bromazepam in human plasma: an automated method for bioequivalence studies.

A validated method for on-line solid-phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry (SPE-HPLC-MS-MS) is described for the quantification of bromazepam in human plasma. The method involves a dilution of 300 muL of plasma with 100 muL of carbamazepine (2.5 ng/mL), used as internal standard, vortex-mixing, centrifugation, and injection of 100 muL of the supernate. The analytes were ionized using positive electrospray mass spectrometry then detected by multiple reaction monitoring (MRM). The m/z transitions 316-->182 (bromazepam) and 237-->194 (carbamazepine) were used for quantification. The calibration curve was linear from 1 ng/mL (limit of quantification) to 200 ng/mL. The retention times of bromazepam and carbamazepine were 2.6 and 3.2 minutes, respectively. The intraday and interday precisions were 3.43%-15.45% and 5.2%-17%, respectively. The intraday and interday accuracy was 94.00%-103.94%. This new automated method has been successfully applied in a bioequivalence study of 2 tablet formulations of 6 mg bromazepam: Lexotan(R) from Produtos Roche Químicos e Farmacêuticos SA, Rio de Janeiro, Brazil (reference) and test formulation from Laboratórios Biosintética Ltda, São Paulo, Brazil. Because the 90% CI of geometric mean ratios between reference and test were completely included in the 80%-125% interval, the 2 formulations were considered bioequivalent. The comparison of different experimental conditions for establishing a dissolution profile in vitro along with our bioavailability data further allowed us to propose rationally based experimental conditions for a dissolution test of bromazepam tablets, actually lacking a pharmacopeial monograph.