Biomedical subjects
Publications and source records attributed to A Raynaud.
This study of 88 adrenal venograms looked at the anatomical variations in the drainage of the principal adrenal veins. These were seen with a frequency of 5% on the right and 6% on the left. On the right, we have described ectopic anastomoses with the hepatic veins. On the left, the variations were always linked to an anomaly of the renal vein.
Recent articles reported excellent results in the percutaneous declotting of native fistulas for hemodialysis with use of thromboaspiration, mechanical devices, or thrombolytic drugs, with success rates ranging from 76% to 100%. These results challenge the surgical approach, the effectiveness of which is not supported by comparable publications. Although it is more difficult to declot forearm native fistulas than grafts, declotting of fistulas is more rewarding because it achieves better long-term patency (1-year primary rates as high as 50% and secondary rates of 80%). The results reported from declotting of fistulas in the upper arm are not as good. The unmasking of stenoses in close to 100% of cases warrants stenosis detection programs similar to those used for grafts.
This study analyzed the initial presentation and revascularization outcomes of patients with radiation-induced renal artery stenosis, a rare complication of therapeutic irradiation. Of 11 patients with renal artery stenosis after irradiation, 7 patients fulfilled the following criteria: normotension before irradiation, radiation dose greater than 25 grays delivered to the renal arteries, associated perirenal radiation-induced lesions, and absence of arterial disease outside the radiation field. The median age at irradiation was 30 years, and the median local irradiation dose was 40 grays. The median time from irradiation to referral was 13 years. All patients were hypertensive at referral, with a median blood pressure (BP) of 171/102 mm Hg and median treatment score of two. The median glomerular filtration rate was 67 mL/min. Two patients had bilateral stenoses and 1 patient had stenosis affecting a single kidney. Stenoses were proximal in 6 patients and truncal in 1 patient, and all had the appearance of atherosclerotic stenosis. Percutaneous transluminal renal artery angioplasty (PTRA) was successful in 5 patients, but required multiple insufflations. PTRA failed in 1 patient, who subsequently underwent an aortorenal bypass. After a median follow-up of 36 months, 2 patients had died of noncardiovascular causes and 4 patients remained hypertensive, with a median BP of 136/85 mm Hg and median treatment score of two. No restenosis occurred, but aneurysms developed at the site of angioplasty in 1 patient. If hypertension occurs even decades after irradiation, a radiation-induced renal artery stenosis should be sought in patients who have undergone abdominal irradiation.
Entrapment syndrome below or just above the elbow is uncommon. These rare causes of neurologic or vascular entrapment are linked to anomalous anatomical structures. No case of entrapment syndrome has been reported in patients with angioaccess for hemodialysis. We report, for the first time, forearm arteries entrapment in two patients presenting with recurrent angioaccess for hemodialysis thrombosis. Anatomical, radiologic, and surgical features of these uncommon syndromes are discussed.
Occurrence of a central venous stenosis or occlusion is a frequent and major complication of indwelling central venous catheters. Two mechanisms may explain such a complication: thrombosis and fibrosis causing progressive stenosis. When these central vein lesions are symptomatic or preclude the creation of an angio-access for hemodialysis, they should be treated. Then, the first choice treatment is interventional radiology. Thromboses are treated by anticoagulation, local fibrinolysis and angioplasty of the residual lesion. Stenoses and chronic occlusions are treated by angioplasty more or less stent implantation. These percutaneous treatments are very effective and incomparably simpler than surgery, which often requires thoracotomy. However, often, such a treatment should be renewed because of the occurrence of a restenosis. Theses central venous lesions should be feared and taken into account for indication of central venous catheter placement.
The secretion and the blood levels of the adrenal steroid dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) decrease profoundly with age, and the question is posed whether administration of the steroid to compensate for the decline counteracts defects associated with aging. The commercial availability of DHEA outside the regular pharmaceutical-medical network in the United States creates a real public health problem that may be resolved only by appropriate long-term clinical trials in elderly men and women. Two hundred and eighty healthy individuals (women and men 60-79 years old) were given DHEA, 50 mg, or placebo, orally, daily for a year in a double-blind, placebo-controlled study. No potentially harmful accumulation of DHEAS and active steroids was recorded. Besides the reestablishment of a "young" concentration of DHEAS, a small increase of testosterone and estradiol was noted, particularly in women, and may be involved in the significantly demonstrated physiological-clinical manifestations here reported. Bone turnover improved selectively in women >70 years old, as assessed by the dual-energy x-ray absorptiometry (DEXA) technique and the decrease of osteoclastic activity. A significant increase in most libido parameters was also found in these older women. Improvement of the skin status was observed, particularly in women, in terms of hydration, epidermal thickness, sebum production, and pigmentation. A number of biological indices confirmed the lack of harmful consequences of this 50 mg/day DHEA administration over one year, also indicating that this kind of replacement therapy normalized some effects of aging, but does not create "supermen/women" (doping).
Renal transplant vein thrombosis is an unusual event occurring in 0.3-3% of renal transplantations. Prognosis is uniformly poor with graft loss in nearly every case. We report here the first three cases of renal graft vein thrombosis successfully treated by percutaneous endoluminal thromboaspiration. After an initially uneventful course all recipients developed anuria and required hemodialysis. In two cases, an ultrasound examination suggested a diagnosis of venous thrombosis. Emergency arteriography and phlebography were performed, confirming the complete thrombosis of the graft veins. Thromboaspiration was carried out with full heparinization and led to renal function improvement in all cases. Grafts are still functioning 6 months after the procedure, with serum creatinine levels of 176 mumol/l, 120 mumol/l and 184 mumol/l, respectively. Thus, this procedure avoids surgical and anaesthetic risks and allows, if performed at an early stage, restoration of graft function. Great care must be taken to avoid vein wall damage, vascular suture line rupture, or pulmonary embolism.
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The expression of reelin mRNA and protein was studied during embryonic brain development in the lacertilian lizards L. viridis and L. galloti, by using radioactive in situ hybridization and immunohistochemistry. At all stages studied, high reelin expression was consistently found in the olfactory bulb, in the lateral cortex, and in neurons of the marginal zone and subplate of medial and dorsal cortical sectors. In the dorsal ventricular ridge (DVR), reelin expression was confined to deeply located, large cells which were more abundant in the caudal than the rostral part of the DVR. In the diencephalon, the ventral lateral geniculate complex and the perirotundal were strongly positive, whereas other nuclei were mostly negative. High reelin signal was associated with some layers in the tectum, with the torus semicircularis, cerebellar granule cell layers, and the ventral horn of the spinal cord. A more moderate signal was detected in the septal nuclei, striatum, retina, habenular nuclei, preoptic and periventricular hypothalamic components, and in reticular nuclei of the mid- and hindbrain. The medial and dorsal cortical plate and Purkinje cells were reelin-negative but expressed disabled-1 (Dab1) mRNA. When they are compared with reelin expression during mammalian brain development, our data reveal an evolutionarily conserved canvas of reelin expression, as well as significant differences, particularly in developing cortical fields. The developing lizard cortex differs from that of turtles, birds, crocodiles, and mammals in that it displays heavy reelin expression not only in neurons of the marginal zone that might be homologous to mammalian Cajal-Retzius cells, but also in subplate neurons. This difference in the pattern of reelin expression suggests that the elaborate radial organization of the lacertilian cortical plate, somewhat reminiscent of its mammalian counterpart, results from evolutionary convergence. Our data lend support to the hypothesis that the reelin signaling pathway played a significant role during cortical evolution.
Hand ischemic steal syndrome due to a forearm arteriovenous fistula is a rare occurrence. We report here a case in which we applied a new diagnostic method to assess the efficacy of distal radial ligation to treat this syndrome. A favorable comparison of distal radial artery pressure measurements before and after temporary occlusion of the artery with a balloon catheter indicated that perfusion of the hand would be dramatically improved after surgical artery ligation.
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We report a case of idiopathic renal arteriovenous fistula revealed by microscopic hematuria in a 36-year-old man with no predisposing history. Treatment with selective embolization achieved complete resolution with no parenchymal damage.
Data for the effects on blood pressure of renal artery balloon angioplasty are mostly from uncontrolled studies. The aim of this study was to document the efficacy and safety of angioplasty for lowering blood pressure in patients with atherosclerotic renal artery stenosis. Patients were randomly assigned antihypertensive drug treatment (control group, n = 26) or angioplasty (n = 23). Twenty-four-hour ambulatory blood pressure, the primary end point, was measured at baseline and at termination. Termination took place 6 months after randomization or earlier in patients who developed refractory hypertension. In those allocated angioplasty, antihypertensive treatment was discontinued after the procedure but was subsequently resumed if hypertension persisted. Secondary end points were the treatment score and the incidence of complications. Two patients in the control group and 6 in the angioplasty group suffered procedural complications (relative risk, 3.4; 95% confidence interval, 0.8 to 15.1). Early termination was required for refractory hypertension in 7 patients in the control group. Antihypertensive treatment was resumed in 17 patients in the angioplasty group. Mean ambulatory blood pressure at termination did not differ between control (141+/-15/84+/-11 mm Hg) and angioplasty (140+/-15/81+/-9 mm Hg) groups. Angioplasty reduced by 60% the probability of having a treatment score of 2 or more at termination (relative risk, 0.4; 95% confidence interval, 0.2 to 0.7). There was 1 case of dissection with segmental renal infarction and 3 of restenosis in the angioplasty group. No patient suffered renal artery thrombosis. In unilateral atherosclerotic renal artery stenosis, angioplasty is a drug-sparing procedure that involves some morbidity. Previous uncontrolled and unblinded assessments of angioplasty overestimated its potential for lowering blood pressure.
Variation in segment number is an important but neglected feature of vertebrate evolution. Some vertebrates have as few as six trunk vertebrae, while others have hundreds. We examine this phenomenon in relation to recent models of evolution and development. Surprisingly, differences in vertebral number are foreshadowed by different somite counts at the tailbud stage, thought to be a highly conserved (phylotypic) stage. Somite number therefore violates the 'developmental hourglass' model. We argue that this is because somitogenesis shows uncoupling or dissociation from the conserved positional field encoded by genes of the zootype. Several other systems show this kind of dissociation, including limbs and feathers. Bmp-7 expression patterns demonstrate dissociation in the chick pharyngeal arches. This makes it difficult to recognise a common stage of pharyngeal development or 'pharyngula' in all species. Rhombomere number is more stable during evolution than somite number, possibly because segmentation and positional specification in the hindbrain are relatively interdependent. Although developmental mechanisms are strongly conserved, dissociation allows at least some major evolutionary changes to be generated in phylotypic stages.
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