Synergy of Turbulent Momentum Drive and Magnetic Braking.

In absence of external torque, plasma rotation in tokamaks results from a balance between collisional magnetic braking and turbulent drive. The outcome of this competition and cooperation is essential to determine the plasma flow. A reduced model, supported by gyrokinetic simulations, is first used to explain and quantify the competition only. The ripple amplitude above which magnetic drag overcomes turbulent viscosity is obtained. The synergetic impact of ripple on the turbulent toroidal Reynolds stress is explored. Simulations show that the main effect comes from an enhancement of the radial electric field shear by the ripple, which in turn impacts the residual stress.

[Exercise-induced renal ischemia after kidney transplantation: report of two cases]. / Ischémie rénale d'effort sur rein transplanté : à propos de deux cas.

INTRODUCTION: Renal transplant patients are high cardiovascular risk patients. Regular ultrasound surveillance of the renal transplant artery and the iliac artery upstream from the anastomosis is required to detect potential arterial stenosis. The purpose of this article was to illustrate the hemodynamic impact of exercise in such patients and the screening efficiency of Doppler ultrasound stress testing. METHODS: Two renal transplant patients were hospitalized in our center for impaired renal function, worsening hypertension, and intermittent claudication. This association of peripheral vascular disease and renal dysfunction led us to perform a Doppler ultrasound stress test to search for vascular stenosis upstream from the graft. Hemodynamic fluctuations in the ipsilateral leg were recorded during flexion-extension exercises. RESULTS: Iliac artery lesions were found in both patients: the Doppler examination showed decreased systolic velocity in the graft artery during exercise, compatible with iliac steal syndrome. Surgical treatment was performed in both patients. After surgery, the control Doppler ultrasound stress test showed that systolic flow did not decline in the graft vessels during exercise. Renal function stabilized in one patient and improved in the other; claudication disappeared after surgery. CONCLUSION: Doppler ultrasound stress testing can be a valuable tool for detecting exercise-induced renal graft ischemia in transplant patients. Its screening performance should be determined in a larger population before routine use.

[Arterial vascularization of the foot. Its importance in operations of revascularization of the lower limb]. / Vascularisation artérielle du pied. Son importance dans les interventions de revascularisation du membre inférieur.

Vascularization of the foot was studied using 50 intraoperative arteriograms on single legs and 50 cadaver injections. Arterial vascularization was shown to depend on supramalleolar anastomoses, the primary plantar arch and secondary arches. Anastomotic routes are essential for the permeability of femorotibial bypasses and cicatrization of distal trophic lesions when only one tibial artery remains permeable and must be revascularized.

In situ thrombolysis for late occlusion of suprafemoral prosthetic grafts.

Low-dose urokinase was used to obtain in situ thrombolysis in the treatment of 20 late occlusions of suprafemoral prosthetic grafts in 19 patients. Aortofemoral or aortobifemoral bypasses with occlusion of one limb had been performed in nine patients, direct iliofemoral bypasses in six, crossover iliofemoral bypasses in two, and axillofemoral bypasses in three. Sixteen of the grafts were polytetrafluoroethylene and four were Dacron. Vascular surgery had been performed on an average of 3 years earlier. Thrombolysis was inhibited on an average of 3 days after onset of occlusion. The protocol called for penetration of the thrombus with a 5 F catheter inserted through a brachial (12 cases) or femoral (eight cases) route. After initial injection of 2500 units of urokinase a continuous infusion of urokinase was begun at a dose of 2500 units/hr and heparin at 100 units/kg/12 hr. Clinical, biochemical (fibrinogen and activated cephalin time every 6 hours), and arteriographic surveillance was carried out every 12 hours with progressive mobilization of the catheter until complete clearance of the artery. Clearance was achieved in all cases. Anteroposterior and occasionally lateral arteriograms with the hip joint in flexion were obtained. An organic cause amenable to treatment was found in 16 cases, including distal or proximal lesions (two and 10 cases, respectively) and elongation/kinking (four cases). Endoluminal angioplasty, stenting, or endarterectomy (six cases) and conventional procedures (10 cases) were also performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Transthoracic endoscopy for upper thoracic chemical sympathectomy.

Beginning in April 1989, we have performed eight upper thoracic chemical sympathectomies by transthoracic endoscopy. The indications were occlusive arterial disease in four patients and Raynaud's syndrome and palmar hyperhidrosis in two patients each. Transthoracic endoscopy was performed under general anesthesia, through the third costal interspace on the anterior mid-clavicular line. Five ml of phenol were injected into the parietal pleura covering the three proximal thoracic ganglia. The duration of thoracic drainage was 24 hours. The postoperative course was uneventful except for one case of subcutaneous emphysema and transient Horner's syndrome in three instances. There were no initial failures. Because of its simplicity and the short hospitalization period, chemical sympathectomy by transthoracic endoscopy constitutes a valuable alternative to conventional surgery. This technique is, however, limited in the case of antecedent pleuropulmonary disorders.

Reconstruction of an abnormal artery observed in an 11 mm embryo: considerations on the embryologic origin of the subclavian artery.

The retro-oesophageal right subclavian a. is a classical variant. We report the first case recognised in the embryo (11 mm subject reconstructed by Born's method). Four other adult cases are analysed (1 dissection and 3 clinical cases) and compared with 250 clinical observations of the supraaortic trunks. In the modal state it arises from the 7th arterial segment. The origin of the subclavian and vertebral aa. and the arrangement of the supraaortic trunks allow the distinction of three types, whose embryologic origin is discussed.

[Isolated congenital stenoses of the extrahepatic bile ducts. Review of the literature apropos of a new case]. / Les sténoses congénitales isolées des voies biliaires extrahépatiques. Revue de la littérature à propos d'une nouvelle observation.

The authors describe a case of congenital stenosis of the common hepatic duct, in ten-year-old girl, with jaundice for two months. Ultrasonography showed an intra and extrahepatic duct dilatation. The operative cholangiogram demonstrated severe stenosis at the end of the common hepatic duct. A Roux-en-Y anastomosis of the jejunum to this duct relieved the obstruction. Histopathological examination of the removed stricture showed non inflammatory fibrous structures. The congenital biliary strictures are exceptional. The review of the literature allowed to collect nine other cases, which symptoms began before fifteen years old. Only four were treated in childhood. The arguments for a malformative origin of the stricture are the patient's age, the seat of the stenosis and its histological structure. Several physiopathological theories allowed to explain the usually delayed beginning of first symptoms: distortion of the stenosis by gradual distension, biliary sludge, lithiasis and infection. The preoperative diagnosis of the stricture may now be made by transhepatic or endoscopic cholangiography, but before to assert its congenital feature, it must eliminate many intrinsic or extrinsic causes: post operative, traumatic, inflammatory and tumoral. The Roux-en-Y hepaticojejunostomy is the usual treatment.

Immunolocalization of the protease kallikrein in the colon.

Colon kallikrein was localized in the goblet cells of cat and man by a variety of immunocytochemical techniques. No evidence of this enzyme was found in other sites in this organ. The possible physiological significance of kallikrein in the gastrointestinal tract and of the many related serine proteases is discussed.

Ultrastructural immunolocalization of kallikrein in apical granules of striated duct cells of cat submandibular gland.

Recent studies on the localization of the serine protease salivary kallikrein have led to the conclusion that it has a ductal localization and to the possibility that it is located there in small "secretory" granules. Until now, the latter inference has been based entirely on circumstantial evidence. In the present study, however, direct evidence from immunolocalization studies at the ultrastructural level establishes the localization of this enzyme in the apical duct granules in the cat submandibular gland. These granules stained only with immune sera to cat submandibular gland kallikrein and were the only subcellular structures that did so. They showed the "studded" appearance characteristic of the electron-dense aggregates of peroxidase-antiperoxidase seen in this type of immune reaction.

Localization of kallikrein in submandibular gland of cat, guinea pig, dog, and man by the immunoperoxidase method.

The sensitive immunoperoxidase method was used to localize kallikrein in the submandibular gland of the cat, guinea pig, dog, and man. In every instance, kallikrein was localized in the apical region of duct cells, a location suggesting its secretion into the duct system. There was no evidence of the enzyme in other cells or interstitial tissue in the gland. The major source of submandibular gland kallikrein, therefore, must be of ductal origin. The classification of kallikreins with the widely distributed group of serine proteases is discussed, as is their possible significance in regulating physiological processes by specific and limited proteolysis.