HEMOGLOBIN-OXYGEN AFFINITY IN HYPOPHOSPHATEMIC RICKETS

Abstract. In 14 patients with simple X–linked hypophosphatemic rickets, 5 were below the third percentile in height and 9 were between the third and twenty-fifth percentile. Although the mean serum inorganic phosphorus level was only 2.01±0.65 (normal range for all age groups is 3.8 to 6.0 mg/100 ml), both the mean values for red cell 2,3-diphosphoglycerate (2,3-DPG) and adenosine triphosphate (ATP) were normal at 4.78±1.23 and 1.02±0.17 μmol/ml of red blood cells respectively. Moreover, the mean P₅₀ value was normal at 26.4±0.9 mmHg. These normal oxygen transport data make unlikely any proposal that short stature seen in these patients is secondary to chronic tissue hypoxia. They also indicate that the intra-erythrocytic organic phosphate levels are maintained at normal levels despite profound chronic hypophosphatemia.     

Pathological and Hepatic Ultrastructural Effects of a Single Dose of Perfluoro-n-decanoic Acid in the Rat, Hamster, Mouse, and Guinea Pig

In rats, the liver is the primary target organ of perfluoro-n-decanoicacid (PFDA) toxicity. Therefore, the effects of PFDA on hepaticultrastructure were studied in rats. Pathological changes inducedby PFDA in hamsters, mice, and guinea pigs were also examined.PFDA caused a severe reduction in body weight in all four speciesstudied. A reduction in food intake was observed in rats andhamsters. However, hamsters continued to consume food at a reducedlevel, while rats stopped eating for a 5 to 6-day period about6 days after dosing. The PFDA-induced pathological changes inthe hamsters, mice, and guinea pigs resembled those seen inrats to varying degrees. As in the rat, PFDA caused a markedliver enlargement in mice and hamsters and a moderate swellingin guinea pigs. This hepatomegaly was ascribed primarily toindividual cell swelling. Thymic atrophy was noted in PFDA-treatedhamsters, mice, and guinea pigs. Seminiferous tubular degenerationobserved in hamsters and guinea pigs, but not in mice, was notas severe as in the rat, where in some cases frank necrosishas been seen. Ultrastructural changes in the livers of allPFDA-treated animals, regardless of species, included disruptionof the rough endo plasmic reticulum, rounding and swelling ofthe mitochondria with related structural alter ations, and mildto extensive proliferation of peroxisomes. This peroxisome proliferativeresponse was greatest in mice and almost absent in guinea pigs.Accumulation of lipid droplets in liver cells due to PFDA treatmentwas more pronounced in hamsters and guinea pigs than in ratsand mice. PFDA-induced hepatomegaly with a concomitant increasein peroxisomes in several rodent species may be associated withan impairment of normal lipid metabolism in the liver by PFDA.     

U.S. Experience with the AddVent VDD(R) Pacing System

The AddVent pacemaker generator and model 1328C AV single-pass lead is a new pacemaker system capable of VDD or VDDR modes. The purpose of this study was to present the initial experience with AddVent in the United States and Canada. Between May 10, 1995 and May 3, 1996, 53 devices were implanted in 52 patients and followed for a mean of 217 (±39) days. At the predischarge, 1-, 3-, and 6-month follow-up evaluations, atrial sensing thresholds and ventricular sensing and capture thresholds were measured in the supine, sitting, and standing positions to evaluate stability of atrial sensing with respect to body posture at rest. At the 1-month follow-up, a treadmill exercise test was performed to evaluate atrial sensing during exercise and to evaluate two new features of the AddVent called "sensor-mediated rate smoothing" and "preferential P wave sensing." Atrial sensing thresholds were not significantly different (P > 0.05) among body postures for any follow-up period or among follow-up periods for each posture. At rest, the percentage of appropriately tracked P waves observed was > 99% at each follow-up period. During treadmill exercise, the percentage of appropriately tracked P waves was > 98.7%. Appropriate preferential P wave sensing and sensor-mediated rate smoothing (VDDR mode) was observed. The AddVent pacing system provides safe and effective pacing therapy. Several features of VDDR pacing offer advantages over standard VDD pacing.     

Parenteral Antiarrhythmic Drug Therapy in Ventricular Tachycardia/Ventricular Fibrillation: Evolving Role of Class III Agents—Focus on Amiodarone

Intravenous Amiodarone. More effective intravenous antiarrhythmic agents are required for treatment of patients with refractory malignant ventricular arrhythmias. More recently, a great deal of interest has been focused on use of intravenous amiodarone for these patients. Uncontrolled early studies showed that intravenous amiodarone was effective in 42% to 81% of treated patients. Recent large cooperative trials have documented the efficacy of intravenous amiodarone in these patients and have shown an efficacy comparable to bretylium in patients with refractory sustained ventricular tachycardia or fibrillation.     

Catecholaminergic Polymorphic Ventricular Tachycardia with QT Prolongation

The QT interval in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) is typically normal. However, CPVT patients are sometimes misdiagnosed as concealed long QT syndrome (LQTS), because patients with LQTS also manifest with syncope or sudden death following periods of exertion or extreme emotion. We report a CPVT patient with a pathogenic RyR2 mutation associated with a marked QT prolongation, which normalized after flecainide therapy.     

《国际功能、残疾和健康分类》:对康复策略进行统一概念描述的模式

成功开展康复实践和研究工作的重要基础是将其作为健康策略来全面地描述康复概念，而一个被广泛接受的概念模式与人类功能概念和分类则是健康策略的基础。2001年，世界卫生大会批准了《国际功能、残疾和健康分类3（ICF），并在2005年召开的世界卫生大会上通过关于ICF的《残疾，包括预防、管理和康复》的决议，因此，我们可以依据一种被广泛接受的概念模式解决相关的残疾与康复问题。我们应抓住机遇，及时发展基于ICF的概念描述，它可以作为类似领域概念描述的基础，并根据专业的定义在人类功能与康复研究的不同科学领域中运用康复策略。目前，通过与欧洲医学联盟（UEMS）物理和康复医学（PRM）专业委员会的专家和其专业委员会的紧密合作，笔者已经完成了第一个基于ICF的概念描述的版本，用简短的文字描述康复的定义。PRM专业委员会、卫生部门和其他行业的专业人士共同将该定义应用于服务人群，其目的是让那些健康状况处于残疾或可能会有残疾的人在与环境的交互作用中实现和保持最佳功能。     

Diagnosis and Ablation of Multiform Fascicular Tachycardia

Ablation Multiform Fascicular Tachycardia . Introduction: Fascicular tachycardia (FT) is an uncommon cause of monomorphic sustained ventricular tachycardia (VT). We describe 6 cases of FT with multiform QRS morphologies. Methods and Results : Six of 823 consecutive VT cases were retrospectively analyzed and found attributable to FT with multiform QRS patterns, with 3 cases exhibiting narrow QRS VT as well. All underwent electrophysiology study including fascicular potential mapping, entrainment pacing, and electroanatomic mapping. The first 3 cases describe similar multiform VT patterns with successful ablation in the upper mid septum. Initially, a right bundle branch block (RBBB) VT with superior axis was induced. Radiofrequency catheter ablation (RFCA) targeting the left posterior fascicle (LPF) resulted in a second VT with RBBB inferior axis. RFCA in the upper septum just apical to the LBB potential abolished VT in all cases. Cases 4 and 5 showed RBBB VT with alternating fascicular block compatible with upper septal dependent VT, resulting in bundle branch reentrant VT (BBRT) after ablation of LPF and left anterior fascicle (LAF). Finally, Cases 5 and 6 demonstrated spontaneous shift in QRS morphology during VT, implicating participation of a third fascicle. In Case 6, successful ablation was achieved over the proximal LAF, likely representing insertion of the auxiliary fascicle near the proximal LAF. Conclusions : Multiform FTs show a reentrant mechanism using multiple fascicular branches. We hypothesize that retrograde conduction over the septal fascicle produces alternate fascicular patterns as well as narrow VT forms. Ablation of the respective fascicle was successful in abolishing FT but does not preclude development of BBRT unless septal fascicle is targeted and ablated. (J Cardiovasc Electrophysiol, Vol. 24, pp. 297‐304, March 2013)     

Prevalence of Hyperglycaemia and Undiagnosed Diabetes Mellitus in Patients with Acute Myocardial Infarction

ABSTRACT The prevalence of hyperglycaemia and undiagnosed diabetes mellitus was assessed in 214 consecutive patients admitted to the coronary care units with acute myocardial infarction (AMI). On admission, 16 patients (7.5%) had known diabetes, and 19 patients, not previously known to be diabetic, had blood glucose concentrations of ≥9 mmol/1. Fifteen patients survived for 2 months at which time a 75 g oral glucose tolerance test showed diabetes in 9 (60%) and impaired glucose tolerance in 4 (27%). Ten of these 13 patients (77%) with abnormal glucose tolerance had elevated glycosylated haemoglobin (HbA_1c) on admission, indicating pre-existing glucose intolerance or diabetes. The prevalence of undiagnosed diabetes was 4.5% (9/198). However, we may have overlooked undiagnosed diabetes in a small number of patients on admission, since only a random blood glucose <8 mmol/1 rules out diabetes, WHO criteria. Elevated blood glucose in patients with AMI is more likely to reflect a stationary pre-existing abnormal glucose tolerance than a temporary stress-induced phenomenon.