Dexmedetomidine, a highly selective and potent alpha-2 adrenoceptor agonist, reduces halothane anesthetic requirements by over 90% in rats. The present study examined whether dexmedetomidine produces a hypnotic-anesthetic action in rats. Dexmedetomidine induced a hypnotic-anesthetic state in rats characterized by loss of righting reflex at doses greater than or equal to 0.1 mg/kg. This response was dose-dependent between 0.1 and 3 mg/kg.
This review focuses on the mechanisms and sites of action underlying beta-adrenergic antagonism in perioperative medicine. A large body of knowledge has recently emerged from basic and clinical research concerning the mechanisms of the life-saving effects of beta-adrenergic antagonists (beta-AAs) in high-risk cardiac patients. This article re-emphasizes the mechanisms underlying beta-adrenergic antagonism and also illuminates novel rationales behind the use of perioperative beta-AAs from a biological point of view.
BACKGROUND AND OBJECTIVE: This randomized, double-blinded, prospective study compared the effects of clonidine, esmolol or alfentanil on the level of hypnosis and haemodynamic responses to intravenous induction of anaesthesia and endotracheal intubation. METHODS: Forty-five patients scheduled for elective surgery were allotted to one of three groups. They were given either alfentanil 3 microg kg(-1) min(-1) (n = 15); esmolol 1 mg kg(-1) min(-1) (n = 16) or clonidine 3 microg kg(-1) (n = 14) as a 10 min infusion.
BACKGROUND: Malaria remains a serious health problem because resistance develops to all currently used drugs when their parasite targets mutate. Novel antimalarial drug targets are urgently needed to reduce global morbidity and mortality. Our prior results suggested that inhibiting erythrocyte Gs signaling blocked invasion by the human malaria parasite Plasmodium falciparum. METHODS AND FINDINGS: We investigated the erythrocyte guanine nucleotide regulatory protein Gs as a novel antimalarial target.
STUDY OBJECTIVES: In the United States alone, approximately 22 million people take beta-blockers chronically. These medications suppress endogenous nighttime melatonin secretion, which may explain a reported side effect of insomnia. Therefore, we tested whether nightly melatonin supplementation improves sleep in hypertensive patients treated with beta-blockers. DESIGN: Randomized, double-blind, placebo-controlled, parallel-group design. SETTING: Clinical and Translational Research Center at Brigham and Women's Hospital, Boston.
OBJECTIVES: The purpose of this study was to review the results of investigation and management of children with syncope and a structurally normal heart. BACKGROUND: Syncope is a common clinical problem and has many etiologies. Autonomic testing and, in particular, the tilt/orthostatic test have helped to positively diagnose neurocardiogenic syncope in a high proportion of such patients. METHODS: Patient case notes and autonomic test charts were reviewed in 162 children aged 1 to 20 years (mean age 12.8 years) with syncope.
BACKGROUND: Goal of our study was the comparison of the efficacy of various minimal invasive therapeutic regimens for clinically complete central retinal artery occlusion (CRAO) and the comparison with the literature. PATIENTS AND METHODS: In a retrospective study 93 patients treated for CRAO during the period 1994-1998 were identified. 65 of these patients with clinically complete occlusion without a cilioretinal artery were included in the study. Analysis focused on the results of different therapies and the duration of visual impairment till starting treatment.
Syncope associated with the act of swallowing (deglutition syncope) and syncope associated with head and neck cancers have been documented independently. We present a case of syncope precipitated by a combination of both these mechanisms. It is important to recognize the coexistence of different hemodynamically significant mechanisms leading to syncope. A 66-year-old male recently diagnosed with head and neck cancer presented with syncope associated with eating. Diagnosis was complicated because of multiple factors in this patient, which individually could have led to syncope.
