MECHANISMS OF HALOTHANE ADSORPTION BY DRY SODA-LIME

Using fresh soda-lime (15% water by weight) the soda lime/airpartition coefficient of halothane was found to decrease asa function of vapour phase halothane concentration from 2 40at 0.3% halothane by volume to 1.15 at 2.6percnt;, but adsorptiongenerally followed Henry's law. However, soda-lime dried toa constant weight and subsequently exposed to various concentranonsof halothane adsorbed approximately 320 µlitre of vaporizedliquid halothane per 100 g before a measurable concentrationof halothane was detected in the vapour phase. Adding additionalhalothane then caused a linear increase in vapour concentration.We conclude that dry soda-lime can adsorb large quantities ofhalothane by a mechanism which is nimilar to that of a molecularsieve. After these "high affinity" sites are satisfied, additionalhalothane is adsorbed by a mechanism following Henry's law.     

Ventricular Tachycardia/Ventricular Fibrillation Ablation in the Setting of Ischemic Heart Disease

Recurrent ventricular tachycardia (VT) in the setting of coronary artery disease is frequently a life-threatening electrophysiologic emergency. Even in patients with an implantable defibrillator, recurrent VT is frequently accompanied by repeated and disabling shock therapy. Catheter ablative therapy offers the ability to provide immediate control of recurrent VT. Long-term elimination of VT should be anticipated in most patients. This article reviews the strategies, tools, techniques, and expected outcome for catheter ablation of stable and unstable ventricular arrhythmias in the setting ischemic heart disease.     

Prevention of Spontaneous Sustained Ventricular Tachycardia in the Postinfarction Dog by Left Stellate Ganglionectomy

Suppression of Sustained VT by Left Stellectomy. Holter monitoring and ventricular pacing were used to examine control, right stellate ganglionectomy, and left stellate ganglionectomy treatment groups, 6-24 hours after left anterior descending coronary artery ligation in dogs. In nine of 27 controls (33%), spontaneous ventricular triplets (358 ± 8 beats/min) initiated sustained monomorphic ventricular tachycardia (386 ± 16 beats/min), followed by ventricular fibrillation at 12.6 ± 1.4 hours. Ventricular pacing produced sustained monomorphic ventricular tachycardia in 13 of 18 survivors (73%) at 24 hours. Left but not right stellectomy performed 15 minutes before coronary artery ligation reduced the incidence of spontaneous sustained monomorphic ventricular tachycardia (2 of 27, 7%, P = 0.06; 7 of 27, 26%, P = 0.50, respectively) and reduced the maximal ventricular triplet rate (332 ± 12, P <0.05 and 358 ± 10 beats/min, respectively, P = NS vs control). Neither left nor right stellectomy altered the incidence of ventricular triplets during the 6-24 hour period (153 ± 58 and 222 ± 55/hour, respectively, vs control, 177 ± 59/hour, P = NS) nor prevented pacing-induced sustained monomorphic ventricular tachycardia in the survivors at 24 hours (20 of 24, 75%; and 16 of 20, 80%, P = NS). The data demonstrate that left but not right stellectomy reduces spontaneous sustained ventricular tachycardia and ventricular fibrillation during the 6-24 hour period following coronary artery ligation in the dog. Left stellectomy reduces the triggers for sustained monomorphic ventricular tachycardia (rapid ventricular triplets) without altering the underlying reentrant substrate for sustained ventricular tachycardia.     

Retreatment of endodontic fillings

Abstract— Effects of endodontic retreatment on quality of seal and periapical healing were assessed among 660 previously root-filled roots. The roots were divided into either of two groups according to presence or absence of pathologic alterations in the periapical area. The retreatments, which were carried out by dental students, involved a thorough chemomechanical debridement of the root-canal system aiming to control infection. Following a 2-year observation period 556 roots were reexamined clinically and radiographically. The results showed that root-fillings with technical shortcomings could, following retreatment, be markedly improved as regards effectiveness of seal and distance to the apex. A large number of lumina discernible apical to root-filling could also be treated and filled. Seventy-eight percent of the cases with pathologic lesion present periapically prior to retreatment either completely healed or displayed an obvious size-reduction of the process Retreatments carried out because of technical inadequacies alone were successful in 94% of the cases. It was concluded that renewed endodontic treatment whenever possible is the method of choice when treating defective endodontic fillings complicated with pathologic processes periapically. Apical surgery may be attempted if no signs of healing are apparent following observation.     

Iron Deficiency and Autoimmunity in Post-cricoid Webs

The incidence of post-cricoid webs in patients with iron-deficiencyanaemia and a variety of other conditions including thyroiddisease, pernicious anaemia, ulcerative colitis, and Sjögren'ssyndrome has been examined by cinefluorography of swallowing.A total of 32 subjects were found to have a post-cricoid web;17 of these were patients in whom the index diagnosis was irondeficiency. One or more subjects in each of the other groupsstudied were found to have a post-cricoid web, but webs werenot seen in a healthy control group. Definite evidence of iron deficiency either at the time of diagnosisof the web or in the past was obtained in all but five of the32 patients with a post-cricoid web. Clinical and laboratoryfindings in these 32 patients were combined with results inour 72 patients with webs described previously and comparedwith the findings in two control groups. There was a significantincrease in the incidence of angular stomatitis, glossitis,edentia, thyroid disease, and thyroid antibodies in patientswith a post-cricoid web when compared with an iron-deficientcontrol group without a web. A high incidence of malignant diseaseof the upper gastrointestinal tract was also found in patientswith webs. The incidence of gastric parietal cell antibodies was significantlyhigher in patients with iron deficiency, irrespective of thepresence of a web, than in the healthy controls. The role of iron deficiency and autoimmunity in the pathogenesisof post-cricoid webs and the other tissue changes associatedwith iron deficiency is discussed.