Cheap and easy modification of glassy carbon electrode for voltammetric determination of dopamine in the presence of ascorbic acid

Different methods have been proposed to modify glassy carbon electrode in order to determine dopamine [DA], as one of the most important neurotransmitters in central nervous systems of mammalian. These methods are time comsuming and in some cases expensive. In this work, a very simple and cheap pretreatment method is developed for the bare glassy carbon electrode [GCE] to determine DA in the presence of Ascorbic acid [AA]. Cyclic voltammetry as an electrochemical activation procedure was used for activation of glassy carbon electrode in order to separate diffrential pulse peaks of DA and AA. The effect of different parameters such as pH for supporting electrolyte, range of potential and the number of cycles were investigated. Finally, differential pulse voltammetry was used to determine DA in the presence of AA. On the activated electrode under optimum condition, anodic peak of AA shifted to negative potentials and peak current decreased, but the peak current of DA increased. The peak current was linearly proportional to the bulk concentration of DA in the range of 6.5x10-7-1.8x10-5 mol l-1. The limit of detection was 6.2x10-7 mol l-1. A simple and cheap method was developed for the activation of glassy carbon electrode. It was possible to determine DA in the presence of AA on the treated electrode. The proposed method was used to determine DA in pharmacutical samples

[Comparison of remifetanil with halothane as the anesthesia maintenance method regarding endoscopic sinus surgery conditions]

Endoscopic surgery is a new standard method of treatment for chronic sinusitis. During this operation even small amount of bleeding may reduce the visual field of surgeon significantly and make the procedure troublesome. In this study we compared the operative conditions between patients who receive either remifentanil or halothane for general anesthesia. Endoscopic sinus surgery was performed in 60 patients. Pre- medication was done by fentanil and midazolam and induction was done by propofol and atracurium. The patients were divided into two groups and received either halothane or remifentanil for anesthesia maintenance. Monitoring was performed during anesthesia. Bleeding volume was measured and operation field condition was assessed by the surgeon. Patients' characteristics such as age and gender were the same in both groups. Intra- operative systolic blood pressure was significantly lower in the remifentanil group but diastolic and mean blood pressure and heart rate didn't change after induction and during maintenance in either group. Recovery time in the remifentanil group was also significantly shorter than the halothane group. Bleeding volume was also lower and the operation field condition was better in the remifentanil group. Remifentanil is a good choice to maintain an ideal anesthesia for endoscopic sinus surgery

[Effect of mouth breathing etiologies on craniofacial morphology]

Nasal septal deviation and hypertrophy of the adenoids and palatine tonsils are the two common causes of nasopharyngeal obstruction and resulting mouth breathing in children. It is accepted that chronic mouth breathing influences craniofacial growth and development. The aim of this study was to evaluate the differences of craniofacial morphology in children with two different etiological factors of mouth breathing. In this cross sectional study we studied 47 patients aged 6-10 years with predominant mouth breathing during 2005-2007. After otorhinolaryngologic examination, patients were divided into two groups based on the etiology of nasopharyngeal obstruction: group 1 with adenoid hypertrophy and group 2 with nasal septal deviation. Lateral cephalometric radiographs were obtained to assess craniofacial development. For statistical analysis Mann-Whitney and T-student tests were used. With respect to the inclination of the mandibular and palatal planes, anteroposterior relationship of maxilla and mandible to the cranial base, and indexes of facial height proportions, no significant difference was observed between two groups of children with mouth breathing. Only the gonial and craniocervical angle measurements were significantly larger in children with adenoid hypertrophy [P<0.05]. The present study did not show any significant morphological differences between children with adenoid hypertrophy and those with nasal septal deviation. Mouth breathing seems to have a similar effect on craniofacial morphology irrespective of its etiology. Prospective studies with larger samples including older children are suggested