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The endpoint of an endodontic treatment must be situated at the cemen-to-dentinal junction to preserve the biological potential of the periapical area and to realize a complete disinfection of the principal root canal system. Thus, the determination of working length is a crucial factor in endodontic therapy. The conventional radiographic method cannot provide the accurate location of the apical constriction. For this reason, the electronic apex locators have been developed. Now, the last generation of apex locators has become more sophisticated and the electronic measurements seem to be accurate and reliable with electrolytic solutions in the canal.

The multiple cholesterol emboli syndrome (MCES) is a rare, multi-organ disease than can occur spontaneously or after arterial or cardiac catheterization, arteriography, angioplasty, cardiovascular surgery, oral or intravenous anticoagulation, systemic fibrinolysis and cardiorespiratory resuscitation, predominantly in male subjects with disseminated atherosclerosis over the age of 60 years. Clinical signs of MCES vary considerably depending on the organs involved, but the signs most frequently encountered are renal failure, skin lesions (livedo reticularis, purple toc, ulcers, etc) and transient eosinophilia. Optimal treatment of this syndrome is controversial and is often symptomatic. However, the most effective measure remains prevention based on identification of high-risk patients, treatment with platelet antiaggregants and careful handling of catheters. This syndrome has a serious prognosis in the majority of cases. In this article, the authors describe a case of MCES. After thoracic aortography, this 73-years-old patient presented typical clinical sign of MCES (angina, cerebrovascular accident, bilateral blindness, transient renal failure and splenic infarction). The clinical course was favourable in response to heparin therapy and splenectomy and caudal pancreatectomy. Histology confirmed the presence of cholesterol emboli in the lumen of splenic arterioles. Except in the case of severe bleeding diathesis, the authors recommend early heparin therapy for MCES caused by catheterization, angioplasty or cardiovascular surgery. However, complementary studies must be performed to more clearly define the effects of heparin on MCES.

Abdominal aortic coarctation is found in only 2% of aortic coarctation and is usually manifested by renovascular hypertension. Splanchnic arterial occlusive lesions occur in 22% of these patients and are exceptionally symptomatic. We present a case report of a young patient with abdominal aortic coarctation causing hypertension and visceral angina. The aetiopathogeny and treatment are discussed.

We describe the case of a patient with adventitial cystic disease of the popliteal artery in which a direct anatomic communication between the cysts and the nearby knee joint was demonstrated by magnetic resonance imaging and confirmed by surgery. This unusual observation could shed some light on the much debated question of the cause, the pathogenesis, and the management of the affection. Moreover, it emphasizes the importance and the role of magnetic resonance imaging in the diagnosis of adventitial cystic disease of the popliteal artery.

The question of the role of season as a predisposing factor for development of venous thromboembolic disease still remains a matter of debate. Actually, most reports described a higher incidence of thrombotic disorders in winter, while a recent study showed no seasonal variation in the incidence of deep vein thrombosis (DVT). These data led us to study the seasonal distribution of all outpatients with DVT admitted to our Department over a period of 14 years.Retrospective review of the files of all outpatients with confirmed (venography or ultrasound) DVT of the legs admitted from Jan. 1st 1982 to Dec. 31st 1995 (n = 512; mean age 59.4 years; 49.4% women).DVT occurred in spring in 135 (26.4%), in summer in 104 (20.3%), in autumn in 142 (27.7%) and in winter in 131 (25.6%) patients. This distribution appears to be similar to an expected uniform distribution [chi 2(3) df = 6.48; p = 0.090 (NS)].In our study, by investigating retrospectively 512 outpatients with confirmed DVT, no correlation was found between season and development of thrombosis, suggesting that cold seasons do not represent a predisposing factor for DVT. Further large prospective studies are needed in order to validate our data and to investigate the clinical implications and the precise role of the season in the risk of occurrence of venous thrombosis.

Despite improvements in surgical techniques, progress in anesthesia and hemodynamic control, the risk of fatal outcome in the standard surgical technique for aneurysms of the abdominal aorta remains at about 5 to 6% due to associated coronary and pulmonary lesions. Surgical access to the aneurysm may also be hindered in patients with a past history of multiple abdominal operations. In collaboration with the Corvita company, we developed a modular endoprosthesis for endoluminal treatment of AAA and report the results of a feasibility study.

From 1980 to 1985, 134 patients with severe ischemia of lower limbs benefited from surgical recovery by inversed autologous venous graft in subarticular femoropopliteal and distal femoral position. During the 5 year follow-up period, 14 grafts (9%) developed hemodynamic degradation requiring angiographic surveillance followed by surgical repair or percutaneous dilatation. A retrospective study of evolution of venous grafts implanted in the contralateral supra-articular femoropopliteal and femoro (ilio) femoral position demonstrated a lower incidence of hemodynamic degradation (5.3%). Localizations (proximal and distal anastomotic stenosis, valvular stenosis, stenotic degradation of the donor or receiving arterial segment) and physiopathologic mechanisms (progressive atheromatosis, anastomotic or valvular fibrosis, premature atheromatosis of graft) are systematically reviewed together with results of pathology. Etiopathogenic factors invoked for this affection are discussed as a function of findings, together with choice of therapy used, including surgical repair, fibrinolysis and percutaneous dilatation.

The succession of amplitudes constituting spontaneous electroencephalographic activity cannot be regarded as a strictly normal distribution. Spontaneous activity and the evoked response are not independent. The signal (evoked response)is, in some cases, non-stationary. The average visual-evoked response comprises several successive temporal fragments of which the stationary character varies. This variability of the average visual-evoked response argues in favour of the complexity of its genesis.

Various statistical discrimination indices reveal deflections regarded as significant before the 20th ms after stimulation (probably equivalent to Bickford responses or subcortical activity) and between the 20th and 23rd ms (early fractions of MVER). The independence of signal and noise is discussed. Considerations concerning the calculation of retinocortical time are developed.

The authors confirm the presence of very early deflection (before the 20th msec. after the flash). They probably have their origin under the cortex. The curves showing the attenuation of the spontaneous activity during the summation and those illustrating the evolution of the variancy of the early portions of the VER are comparable. By contrast, the stability of the curves related to later fractions state problems about the often pretented independancy of spontaneous and evoked activities.