APANESE neurosurgeons have recently observed in patients of their own race a variety of neurological disorders which are often transient and appear most frequently in young people. The typical angiographic appearance is that of narrowing or occlusion of both internal carotid arteries at the level of the siphon (C-1) together with a hemangiomatous network at the base of the brain (Fig. 1). These patients were initially reported as having a type of occlusive disease of the internal carotid artery. 1~ The entity has also been reported by other Japanese authors as occlusion of the circle of Willis, 3 telangiectasia, 1,11 or vascular malformation. ~,9 In 1964 we collected 21 case reports from the Japanese literature, added three of our own, r and concluded that the entity was unique to the Japanese. We reported the entity as "hemangiomatous malformation of bilateral internal carotid arteries at the base of the brain" and noted the similarity of the abnormal vasculature to the vascular network in the embryo. We noted, too, that the malformation was primarily limited to the distribution of the internal carotid arteries, s The term "cerebral rete mirabile" has some descriptive value although it is probably not entirely appropriate. The Western literature yielded only one similar case with bilateral involvement, and this patient was a Japanese woman. 1' Taveras and Wood ~ reported comparable cases in non-Japanese patients, but the occlusions were unilateral. Since our paper 6 in 1964, numerous other reports have appeared in the Japanese literature. Adding these to an additional number collected by writing all the neurosurgical clinics in Japan, we are now reporting a total of 96 cases.

Setting-Tertiary adult congenital cardiac referral centre. Design-Retrospective cross sectional analysis. Objectives-To report our 20 year experience with adult Fontan operations, and to compare late outcome in patients with single ventricle with definitive aortopulmonary or cavopulmonary shunt palliation. Patients and main outcome measures-Patients older than 18 years undergoing Fontan operation between 1 January 1982 and 31 December 1998 were identified. Mortality and late outcome were derived from hospital records. These patients were compared with a cohort of 50 adults with single ventricle who had not undergone a Fontan operation. Results-61 adults, median age 36 years (range 18-47 years), with a median follow up of 10 years (range 0-21 years) were identified. Actuarial survival was 80% at one year, 76% at five years, 72% at 10 years, and 67% at 15 years. Compared with before the Fontan operation, more patients were in New York Heart Association (NYHA) functional class I or II at the latest follow up (80% v 58%, p < 0.001). Systolic ventricular function deteriorated during follow up such that 34% had moderate to severe ventricular dysfunction at the latest follow up compared with 5% before Fontan (p < 0.001). Arrhythmia increased with time (10% before Fontan v 57% after 10 years, p < 0.001). Fontan patients had improved NYHA functional class, ventricular function, atrioventricular regurgitation, and fewer arrhythmias than the non-Fontan group at the latest follow up. Conclusion-The Fontan operation in adults has acceptable early and late mortality. Functional class, systolic ventricular function, atrioventricular regurgitation, and arrhythmia deteriorate late after surgery but to a lesser degree than in non-Fontan patients with a single ventricle. (Heart 2001;86:330-335)

The thermal damage threshold of normal brain tissue was evaluated from immediate and delayed histological changes caused by hyperthermia treatment of normal monkey (Macaca fuscata) brains. A 2450 MHz microwave antenna and an antenna cooling system devised by our group were used for in terstitial hyperthermia treatment. The antenna within the cooling system was inserted through a small craniectomy under general anesthesia. The temperature at a reference point, 4 mm radially away from the surface of the cooling system, was maintained at 42, 43, 44, 45, or 46°C for 60 minutes. Eighteen animals were treated and sacrificed immediately after the treatment, while nine animals were treated and sacrificed 7 days after the treatment. The histological changes were studied microscopically on sec tions stained with HE or Kluver-Barrera's method. The non-survival experiment demonstrated that areas heated at 44°C or below showed no obvious irreversible changes. The survival experiment showed areas heated at 44°C or above developed coagulative necrosis. These histological findings in dicate that thermal damage occurs in normal brain tissue after heating at 44°C or above for 60 minutes, suggesting that the safety limit for brain hyperthermia is 43°C for 60 minutes.