ABSTRACT
The effects of gamma radiation on the stability of microspheres made of a polylactide-co-glycolide 50:50 copolymer (PLGA) and loaded with 40% bupivacaine (BU) were studied. The radiolysis mechanisms of BU and BU-loaded microspheres were investigated by using electronic paramagnetic resonance (EPR) analysis. Microspheres were prepared by means of a spray drying method. Gamma Irradiation was carried out in the open, at the dose of 25 kGy, by using a 60Co source. The stability of BU-loaded microspheres was evaluated over a 1-year period on the basis of drug content and dissolution profile. Non-irradiated microspheres were stable over the whole period under consideration. Immediately after irradiation the amount of BU released after 24 h from irradiated microspheres increased from 17 to 25%; in the following 3 months of storage it increased to about 35%, and then it kept constant for 1 year. Radicals generated by BU irradiation were identified by EPR analysis; the sensitivity to gamma radiation of BU was about four times lower than that of PLGA. Furthermore, the EPR spectra of loaded microspheres showed that the relative abundance of BU radicals plus PLGA radicals was proportionate to the electronic fractions of the components; this implies that no spin transfer BU/PLGA had occurred during gamma irradiation.
Subject(s)
Bupivacaine/chemistry , Bupivacaine/radiation effects , Lactic Acid/chemistry , Lactic Acid/radiation effects , Polyglycolic Acid/chemistry , Polyglycolic Acid/radiation effects , Polymers/chemistry , Polymers/radiation effects , Alanine/chemistry , Biphenyl Compounds , Cobalt Radioisotopes/radiation effects , Drug Stability , Electron Spin Resonance Spectroscopy , Free Radicals/chemistry , Free Radicals/isolation & purification , Gamma Rays , Kinetics , Microspheres , Oxygen , Particle Size , Picrates/chemistry , Polylactic Acid-Polyglycolic Acid Copolymer , Reference Standards , Sensitivity and Specificity , Temperature , Time Factors , VacuumABSTRACT
This work was aimed at evaluating the effects of gamma irradiation on the stability of microspheres made of a poly(lactide-co-glycolide) copolymer (PLGA) and loaded with 15% w/w of clonazepam (CLO). The influence of CLO on PLGA radiolysis mechanisms and the identification of possible irradiation markers were also investigated. Microspheres were prepared by means of a spray-drying method. gamma Irradiation was carried out either under vacuum or in air, at a dose of 25 kGy, by using a 60Co source. The stability of CLO loaded microspheres was evaluated over a 6-month period on the basis of drug content and dissolution profile. Radiolysis mechanisms were investigated by using electronic paramagnetic resonance (EPR) analysis. The microspheres irradiated under vacuum were stable over the considered period of time. After irradiation in air, CLO release rate increased by approximately 10%, and did not change further in the following period of storage. The EPR analysis showed some radicals arising from both the polymeric matrix and the active ingredient. Polymer/CLO spin transfer reactions suggest that CLO had a radio-stabilising effect on the polymeric matrix. In the loaded microspheres, the intensity in time of the CLO radical signal is sufficient for its possible use as irradiation marker.
Subject(s)
Clonazepam/administration & dosage , Lactic Acid/administration & dosage , Polyglycolic Acid/administration & dosage , Polymers/administration & dosage , Calorimetry, Differential Scanning , Clonazepam/chemistry , Clonazepam/radiation effects , Drug Stability , Electron Spin Resonance Spectroscopy , Gamma Rays , Microspheres , Polylactic Acid-Polyglycolic Acid Copolymer , SolubilityABSTRACT
Patient with subaortic stenosis due to the insertion of anomalous chordae tendineae of the mitral valve in the interventricular septum (mitral web) associated with mitral stenosis with diagnosis made by bidimensional echocardiographic study with Doppler and confirmed by hemodynamic study. The patient was submitted to surgical treatment. The anomalous cords were resected and the mitral valve with severe malformation was replaced by a bioprosthesis. The patient had a uneventful recovery and echocardiographic evaluation showed an outflow tract without obstruction, with no gradient, with remnants of the papillary muscles and normo-functioning bioprosthesis.
Subject(s)
Aortic Stenosis, Subvalvular/etiology , Chordae Tendineae/abnormalities , Mitral Valve/abnormalities , Aortic Stenosis, Subvalvular/diagnosis , Aortic Stenosis, Subvalvular/surgery , Chordae Tendineae/surgery , Echocardiography, Doppler , Electrocardiography , Humans , Male , Middle Aged , Mitral Valve/surgery , Ventricular Function, Left/physiologyABSTRACT
The authors report the case of a patient with atrial septal defect who was submitted to surgical treatment when an intrapericardial hernia was found. The septal defect was closed with a bovine pericardial patch and the hernia with a pediculated autogenous pericardial graft. They discuss several aspects of the classification of the hernia, its association with other anomalies, embryogenesis, pathophysiology, prognosis and surgical correction.
Subject(s)
Heart Septal Defects, Atrial/complications , Hernias, Diaphragmatic, Congenital , Child , Female , Heart Septal Defects, Atrial/surgery , Hernia, Diaphragmatic/complications , Hernia, Diaphragmatic/surgery , Humans , Surgical FlapsABSTRACT
Two patients under 8 months of age, with right ventricular fibroma, presented with clinical manifestations of pulmonary stenosis. The diagnosis was established in one by echocardiography and in the other by echocardiography. CT scan and angiocardiographic study. The patients were operated and the tumors were successfully resected.
Subject(s)
Fibroma/surgery , Heart Neoplasms/surgery , Angiocardiography , Echocardiography, Doppler , Female , Fibroma/diagnosis , Heart Neoplasms/diagnosis , Heart Ventricles , Humans , Infant , Male , Tomography, X-Ray ComputedABSTRACT
The authors report a case of Ebstein's anomaly associated to a ventricular septal defect. It is a rare association which leads to a poor prognosis of the disease. They emphasize the clinical findings and the complementary data that lead to the definite diagnosis.
Subject(s)
Ebstein Anomaly/complications , Heart Septal Defects, Ventricular/complications , Cardiomegaly/diagnostic imaging , Echocardiography , Electrocardiography , Humans , Infant , Male , RadiographyABSTRACT
O autor faz uma avaliacao dos modernos metodos de ressecao pulmonar, seus tipos e suas indicacoes. Analisa tambem os cuidados basicos indispensaveis no pre e pos-operatorio
Subject(s)
Pneumonectomy , Surgical Procedures, Operative , Lung Diseases , Lung NeoplasmsABSTRACT
E relatado o caso de um paciente de 50 anos con antecedentes de lues, internado com quadro de infeccao pulmonar e sindrome de compressao da veia cava superior. Estudos radiografico e planigrafico do torax, cavografia e aortografia foram realizados levando ao diagnostico de grande aneurisma do tronco branquiocefalico retardado da carotida direita e subclavia. O paciente foi submetido a cirurgia, fazendo-se incisao mediana prolongada para o pescoco a frente do musculo esternocleidomastoideo e enxerto cruzado entre as duas arterias carotidas. Em seguida, foi instalada circulacao extracorporea classica, pincada a aorta entre o tronco branquiocefalico e a carotida esquerda, ressecado o aneurisma fechando o seu colo junto a aorta, colocando-se enxerto tubular entre a aorta ascendente, a carotida direita e a subclavia direita. A evolucao pos-operatoria foi boa e o paciente se encontra bem tres anos apos.Sao discutidos aspectos referentes as manifestacoes clinicas, tecnicas e taticas operatorias utilizadas na correcao dos aneurismas do tronco branquiocefalico
