Biomedical subjects
Publications and source records attributed to J D Degos.
A 53-year-old patient with Wilsons's disease and without autonomic dysfunction presented on T2-weighted MR study an atypical decreased signal intensity of the putamina and the caudate nuclei. Possible explanations of such a signal abnormalities are discussed.
Positron emission tomography (PET) studies of the cerebral metabolic rate of oxygen (CMRO2) were performed in seven consecutive patients with bilateral paramedian thalamic infarcts (BPTI), selected on neuroradiological and clinical criteria. The latter consisted of sudden onset of coma or confusion followed by a persistent amnesia of varying severity, with or without language impairment and frontal lobe signs. There was a highly significant decrease of CMRO2 for the whole cortex as well as for all the regions analysed: medial-frontal, latero-frontal, temporal, sensorimotor and posterior associative cortex. The mean regional metabolic ratios (region/whole cortex CMRO2) were not significantly different from controls, indicating an essentially uniform effect in the cortex, except the sensorimotor ratio which was significantly increased. Diffuse cortical hypometabolism most likely reflects thalamo-cortical deafferentation secondary to damage to the 'non-specific' thalamic nuclei, while sparing of the latero-ventral thalamus presumably explains the relative preservation of the sensorimotor cortex metabolism. Although no clear-cut individual relationship was found between magnitude of cortical hypometabolism and the severity and pattern of neuropsychological impairment, the data suggest that the former underlies and/or reflects the latter. Further studies with higher resolution PET devices might shed more light on the relationships between distinct cognitive patterns and specific topography of cortical hypometabolism in BPTI patients.
Neurological exacerbation observed in MS patients is usually related to a demyelinating process. We report two patients where hypothermia (32.4 degrees C and 32.5 degrees C) and neurological exacerbation were probably due to a Wernicke encephalopathy (WE). The clinical features and the rapid efficiency of parenteral thiamine were suggestive of WE. Hypothermia is an exceptional symptom observed in MS and has been considered as resulting from hypothalamic demyelination; these two cases showed that WE which is another cause of reversible hypothermia, can be associated with MS.
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Clinical manifestations of multiple sclerosis cannot be exactly correlated with lesions identified by brain imaging, electrophysiology or even anatomy. It is generally accepted that a continuous conduction is possible within some demyelinated fibers, and a conduction block may occur in the CNS white matter without demyelinization. These data explain the possible occurrence of brief, repetitive deficits besides the classical relapses. Among the latter, at least some are not correlated with demyelinization. The knowledge of these mechanisms suggest the possibility of therapy to restore the conduction without a direct action on the demyelinating process.
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Various mitochondrial DNA abnormalities have been described in patients with encephalomyopathies. We performed Southern blot analysis of skeletal muscle mitochondrial DNA in nine adult patients with clinical features and ragged red fibres suggesting mitochondrial dysfunction. Two patients with encephalomyopathy and two with the MERRF syndrome (myoclonus epilepsy with ragged red fibres) had the normal PvuII restriction pattern of muscle mitochondrial DNA. In contrast, mitochondrial DNA deletion was observed in two of six patients with ophthalmoplegia. One suffered from typical Kearns-Sayre syndrome and the other from isolated external ophthalmoplegia. None of these patients had affected relatives. The detection of mitochondrial DNA deletion in external ophthalmoplegia and their site and size support previously reported data.
Proliferation and differentiation of myoblasts from hypertrophic muscles were studied "in vitro" in two cases of syringomyelia with muscle hypertrophy (MH). Their myoblast growth was compared with that of muscle cells sampled on the contralateral side in the same patients and in control subjects. The effect of a circulating factor was tested using patient sera in place of fetal calf and horse sera. The results showed that MH cells were morphologically abnormal (giant and granular). MH myoblasts proliferated more rapidly than contralateral and normal myoblasts, their fusion was accelerated and the resulting myotubes synthesized higher levels of protein. MH sera increased these effects. Serum factors are therefore likely to be involved in "in vivo" muscle hypertrophy. These findings suggest that the pathogenesis of muscle hypertrophy in syringomyelia involves acquired abnormalities due to molecules released in response to neural lesions.
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To compare the merits of 123I-isopropyl-iodoamphetamine (123I-IMP) and 99mTc-HMPAO in showing abnormal brain uptake distribution during cerebral ischemia, we studied ten patients during the subacute phase of their stroke, a period where metabolism and blood flow are frequently uncoupled. SPECT imaging was performed using both radiopharmaceuticals in the 10 patients from 48 h to 4 weeks after onset of symptoms. Two patients out of the 10 had similar defects with 123I-IMP and 99mTc-HMPAO SPECT, the location of the defects corresponding to the area of infarction observed on CT. Six patients had normal 99mTc-HMPAO SPECT and abnormal 123I-IMP SPECT with defects in the area of infarction shown by CT. The remaining 2 patients had hyperactive abnormalities on 99mTc-HMPAO in areas corresponding to defects on the 123I-IMP images. Two of the patients with SPECT mismatches were studied again more than 1 month after onset. On reexamination, 99mTc-HMPAO SPECT which was previously normal or hyperactive became hypoactive with a focal area of decreased activity corresponding to the defect on 123I-IMP. Crossed cerebellar diaschisis was found in 7 patients with 99mTc-HMPAO and was absent for both 123I-IMP and 99mTc-HMPAO in 3. We suggest that SPECT with 99mTc-HMPAO could show transient hyperemia not demonstrated by 123I-IMP whereas in some cases cerebral infarction would be more difficult to demonstrate with 99mTc-HMPAO than with 123I-IMP. SPECT with both tracers is recommended to follow the evolution of strokes in terms of regional cerebral blood flow and tissue metabolism.
A retrospective case-control study was carried out on 230 patients with multiple sclerosis (MS) and 230 controls matched for year of birth and sex. The geographical distribution of residence of MS patients and controls was similar. Two peak ages of onset of MS were observed among woman patients (20-24, 30-34 years). There was no difference in histories of infectious diseases and autoimmune diseases between the two groups. A greater number of hairdressers was noticed among the patient group (p less than 0.05) and three patients (no control) had had professional contact with pathology specimens.