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Biomedical subjects

J C Baron

Publications and source records attributed to J C Baron.

At least 199 records · Page 11Linked to original sources
PubMed1987

[Endoscopic nephrotomy].

A procedure of small endoscopic nephrolithotomy during open surgery for staghorn calculi is described. This procedure is based on the principle of percutaneous nephrolithotomy. Same instruments are used. These endoscopic nephrostomies are less traumatic.

Endoscopy↗
PubMed1987

[Focal chronic ischemia and concomitant migraine: an atypical form of Sturge-Weber angiomatosis?].

A young man with a left hemifacial hemangioma had during a six months period about forty left hemispheric neurologic attacks suggestive of classic migraine. The neurologic examination was normal during the attack-free period. The CT scan (fig. 1) and the M.R.I. study (fig. 2) only showed a moderate interhemispheric asymmetry. The left internal carotid angiogram showed subtle anomalies of the venous system (fig. 3). All the neurologic manifestations ceased as soon as therapy by aspirin was initiated. A Positron Emission Tomography (PET) study with the oxygen 15 continuous inhalation technique was performed 7 months after the last attack in order to measure the regional Cerebral Blood Flow (rCBF), Oxygen Extraction Fraction (rOEF) and Oxygen Consumption (rCMRO2). Striking, statistically significant, alterations were observed in the left temporo-parieto-occipital area (fig. 4) consisting of a "misery perfusion" syndrome (rCBF = 28-38 ml/100 g/mn; rOEF = 0.64-0.80), without alteration in the rCMRO2 (Table). A repeated PET study 12 months later was unchanged. The association of local chronic oligemia and ipsilateral facial hemangioma, ipsilateral cerebral hypotrophy and venous anomalies suggested the diagnosis of atypical leptomeningeal angiomatosis of the Sturge-Weber type. The importance and persistence of the hemodynamic alterations suggest that chronic oligemia and, hence, tissue hypoxia may participate in the pathogenesis of the migraine-like attacks. Moreover, local circulatory stasis with thrombotic events may be implicated, as suggested by the apparent efficacy of aspirin.

Adolescent↗
PubMed1987

[Acquired stenosis of the upper urinary tract after percutaneous nephrolithotomy].

The authors present two well documented cases of extensive acquired stenosis of the infra-pelvic upper urinary tract following percutaneous nephrolithotomy. This type of complication appears to be exceptional as, by combining the series of two centres, it represents only two cases out of more than five hundred cases treated. The delay in appearance is of the order of six months. The more or less complex nature of the procedure does not appear to be responsible. It is difficult to determine the exact mechanism fo this complication: several hypotheses are proposed. A few rare cases have been reported in the literature without raising any particular attention. These complications required difficult reconstructive surgery with a good result in both cases. Although these complications seem to be difficult to prevent, they should be systematically detected by ultrasonography at two months and at six months to avoid delay in the diagnosis of functional renal exclusion.

Adult↗
PubMed1987

[Vesico-urethral fibroscopy. Reflections after 4 years' practice].

The visualisation of the lower urinary tract by the mean of a fiberscope makes an advance when compared to rigid endoscopy mainly in male patient. Technical features of the fiberscopes suitable for urology thus basic technique of the examination are described. Main advantages are painfree and total visual scanning of the mucosa. Disadvantages are very low.

Cystoscopy↗
PubMed1986

Loss of striatal [76Br]bromospiperone binding sites demonstrated by positron tomography in progressive supranuclear palsy.

Using positron tomography and 76Br-labeled bromospiperone, a neuroleptic drug with high affinity for the dopamine (DA) receptors, we have estimated the specific binding of the radiotracer to striatal DA receptors in seven patients suffering from progressive supranuclear palsy. Compared with age- and sex-matched control subjects, we found a significant (p less than 0.02) decrease of the striatum-cerebellum uptake ratio in progressive supranuclear palsy patients, suggesting loss of striatal DA receptors. This in vivo study confirms recent postmortem data on progressive supranuclear palsy patients and provides an explanation for the lack of benefit from L-DOPA and DA agonists in this condition, despite reduced nigrostriatal dopaminergic function.

Aged↗
PubMed1986

Crossed cerebellar diaschisis. Further studies.

To investigate further the topographical, clinical and temporal correlates of crossed cerebellar diaschisis (CCD) after supratentorial stroke, 55 patients suffering from a single unilateral ischaemic stroke in the carotid artery territory were studied with the quantitative oxygen-15 steady-state technique and positron tomography. Fourteen patients had one or more follow-up studies, contributing a total of 72 studies. The phenomenon of CCD, defined by depressed oxygen consumption in the contralateral cerebellum, was statistically significant in 58% of the studies. It was more prominent when the supratentorial infarct involved the internal capsule or the cortical mantle extensively, consistent with the hypothesis that it results from destruction of the corticopontocerebellar fibres. Although CCD was associated with the presence of hemiparesis, it also occurred in patients without hemiparesis and was not seen in all those with hemiparesis, suggesting that destruction of the pyramidal tract is neither necessary nor sufficient to induce CCD. Finally, CCD tended to persist over long periods of time after a stroke, pointing towards a transneuronal degeneration possibly akin to crossed cerebellar atrophy as a likely explanation for CCD. Nevertheless, CCD could be seen within hours of a stroke and sometimes disappeared within a few days, suggesting a temporal continuum between early, potentially reversible functional hypometabolism (diaschisis) and irreversible degeneration.

Adult↗
PubMed1986

Effects of thalamic stroke on energy metabolism of the cerebral cortex. A positron tomography study in man.

Positron emission tomography was used to study the effects of unilateral vascular thalamic lesions on cortical oxygen and glucose utilization in 10 patients. There was significant ipsilateral cortex hypometabolism in 9 of the 10 patients, affecting the whole cortical mantle diffusely. The only patient spared was free of neuropsychological deficit at the time of positron emission tomography. In 4 patients, the magnitude of ipsilateral cortical hypometabolism was significantly less at a follow-up PET study, when neuropsychological function had improved. When taken together, the 14 studies showed a significant tendency for the hypometabolism to improve with time after clinical onset. These data suggest that the ipsilateral cortical hypometabolism results from damage to the thalamocortical connections and reflect either loss of nonspecific activating afferences or a degenerative deafferentation-deafferentation process, or both. Its links with the concept of diaschisis are suggested by its tendency to recover. A causal relationship between cortical hypometabolism and neuropsychological deficit, however, although strongly suggested, cannot be firmly established from the present data.

Adult↗
PubMed1986

Local cerebral glucose utilisation in chronic alcoholics: a positron tomographic study.

Using positron tomography, a study of regional cerebral glucose utilisation was performed prospectively in a highly selected group of six neurologically unaffected primary chronic alcoholics. In this group, neuropsychological, behavioural and CT scan anomalies were comparable with those previously reported in more extensive studies. With respect to age-matched control values, cerebral metabolic rate was not significantly modified in the selected cortical, subcortical and cerebellar regions of interest. However, the metabolic regional distribution index, which reflects the distribution pattern of glucose utilisation, was selectively and significantly decreased in the medio-frontal area, pointing to a limbic metabolic dysfunction apparently linked to chronic alcoholism.

Adult↗
PubMed1986

[Cortical hypometabolism after a thalamic lesion in man: positron tomography study].

We used positron emission tomography to study the effects of unilateral vascular thalamic lesions on cortical oxygen or glucose utilisation in 10 patients. There was a significant ipsilateral cortex hypometabolism in 9 of the 10 patients, affecting diffusely the whole cortical mantle. The only patient spared was free of neuropsychological deficit at time of PET study. In 4 patients, the magnitude of ipsilateral cortical hypometabolism was significantly less at follow-up PET study, together with improved neuropsychological function. When plotted altogether, the 14 studies showed a significant tendency for the hypometabolism to improve with time elapsed since clinical onset. On the whole, these data suggest that the ipsilateral cortical hypometabolism reflects an essentially functional alteration an not only a degenerating process. This most likely indicates a cortical deafferentation due to loss of non-specific thalamo-cortical connections, i.e. a phenomenon akin to "diaschisis". However, a causal relationship between cortical hypometabolism and neuropsychological deficit cannot be firmly established from the present data.

Adult↗
PubMed1986

[Percutaneous nephrolithotomy: perspectives for the future. Analysis of 250 cases in 3 years' experience].

The authors report their experience of percutaneous nephrolithotomy over a period of three years. The analysis of the first 250 cases performed reveals a low morbidity, with serious complications in 1% of cases, and an acceptable complete success rate of 83%. The indications for percutaneous nephrolithotomy have been modified since the opening of an extracorporeal lithotripsy unit. The choice between the two techniques depends on their efficacy and their expected morbidity based on four criteria: the volume, chemical composition and site of the stone and the morphology of the upper urinary tract. Percutaneous nephrolithotomy is the treatment of choice for large stones (greater than 2.5 cm), hard stones or those formed proximally to a stenotic lesion of the urinary tract, which can then be dilated at the same procedure. A combination of the two methods is sometimes uses to treat staghorn calculi with a success rate of 80%. On the other hand, very large staghorn calculi with caliceal branches are best treated by open surgery.

Adolescent↗