Verda Toprak

A histological analysis of the protective effect of ischemic preconditioning in the rat retina.

Purpose. Ischemic preconditioning (IP) protects the retina from the damaging effect of subsequent ischemia in vivo. We aimed to investigate the histological alterations induced by the protective effect of IP to the retina. Methods. The eyes of the rats were rendered ischemic by intra-ocular pressure (IOP) elevation. IP procedure consisted of producing ischemia for 5 minutes. Sham operation was similar to IP procedure except the pressure elevation. The operational eyes of sham and IP group underwent 60 minutes of ischemia 24 hours after the first procedure. The eyes contralateral to the experimental eyes made up the control group. The eyes were histologically analysed one week after the ischemia. Results. The total retinal thickness of the sham group was significantly less than total retinal thickness of the control group (p < 0.001). There was not a significant difference between control and IP group regarding the total retinal thickness (p > 0.05). The thickness of the inner retinal layers of the sham group were significantly less than corresponding retinal layers of the control group (p < 0.001). The inner plexiform layer (IPL) and inner nuclear layer (INL) thickness values of the sham group were significantly less than same layers of the IP group (p < 0.001). Ganglion cell layer (GCL) thickness of the IP group was significantly less than GCL thickness of the control group (p < 0.001). IPL thickness of the IP group was significantly less than that of control groups (p < 0.05). The GCL and total retinal thickness of the IP group were significantly more than thickness of the corresponding layers of the sham group (p < 0.05). Conclusion. IP considerably protects inner retinal layers from subsequent ischemic damage in a high IOP ischemic model. This endogenous process could further be utilized to tailor specific neuroprotective strategies for retinal cells.

Volatile induction and maintenance of anesthesia using laryngeal mask airway in pediatric patients

formed parental consent, 60 children, aged 2 to 8 years, American Society of Anesthesiologists (ASA) class I– II, who were scheduled for minor urogenital surgery were enrolled in this prospective, randomized study. Automated noninvasive blood pressure, ECG, and SpO2 were monitored using a Criticare System 1100 monitor (Criticare System, Waukesha, WI, USA). Respiratory gases were monitored by infrared spectroscope S/5 (Datex-Ohmeda, Helsinki, Finland). Anesthesia was induced by mask with a mixture of O2/N2O by a pediatric Bain system at a fresh gas flow of 6 l·min 1. In both the halothane and the sevoflurane groups (group H and group S, respectively), inspired gas concentrations were increased in stepwise fashion; halothane in 0.5% increments, up to a maximum of 5%; and sevoflurane in 1% increments, up to a maximum of 7%. As soon as consciousness was lost, an intravenous catheter was inserted, after eyelash and protective airway reflexes were lost, and the percent concentration of inhaled anesthetic was decreased to keep hemodynamic stability; then the child was ventilated at that concentration of inhaled anesthetic for another 1min. The LMA was chosen depending on the child’s weight, and placed in the hypopharynx. Simultanously, end-tidal concentrations of the inhaled anesthetics and the percentage concentration of the vaporizer dial were recorded. Neuromuscular blocking drugs were not given. Ventilation was controlled to maintain normocapnia, and fresh gas flow was kept high enough to prevent rebreathing. Anesthesia maintenance was done with a total of 1 minimum alveolar concentration (MAC) of the volatile agent and 50% N2O in oxygen in order to provide hemodynamic stability and LMA tolerance until the end of the surgery. Analgesia was provided by 2μg·kg 1 i.v. fentanyl before skin incision. At the end of the surgery, all anesthetic agents were discontinued, 100% O2 was administered, and the LMA was removed in the operating room when the patient was fully awake.

Subanalgesic doses of ketamine and morphine but not morphine alone, prolong the sensory block time of hyperbaric bupivacaine in unilateral spinal anaesthesia

Abstract Aim: In this study, we aimed to compare the sensory and motor effects of a subanalgesic dose of morphine and morphine + ketamine added to 5% hyperbaric bupivacaine (HB) in unilateral spinal anaesthesia. Methods: 45 patients were randomly assigned to one of three groups. The first group received 1.5 ml 0.5% HB + 0.2 ml saline; the second group received 1.5 ml 0.5% HB + 0.1 ml morphine (0.1 mg) + 0.1 ml saline; the third group received 1.5 ml 0.5% HB + 0.1 ml ketamine (0.5 mg) + 0.1 ml morphine (0.1 mg). Maximum block levels, time to reach that level, time to reach T10 level and block levels after 120 min were recorded. Results: Maximum sensory and motor block levels, time to reach these levels and time to reach T10 level were similar in all three groups, but there was less regression of sensory block level in the third group than in the other two groups. Conclusion: Subanalgesic doses of morphine and ketamine added to 0.5% HB extended the sensory block period but not the motor block in unilateral ...