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Biomedical subjects

C Vial

Publications and source records attributed to C Vial.

At least 91 records · Page 5Linked to original sources
PubMed1995

[Disulfiram (Esperal) toxicity. Apropos of 3 original cases].

Prescribed since 1948 to control chronic alcoholism, disulfiram may cause severe toxicity as report in three cases of acute motive axonal polyneuritis. Disulfiram toxicity may present different clinical aspects: 1) Cytolytic hepatitis with fatal evolution in 30% of cases (fulminant hepatitis), and full recovery for the other 70%. The onset of the symptoms usually occurs as early as 15 days to a maximum of 6 months (most within 2 months) after initiation of treatment. 2) Severe optic neuritis with full recovery in 2 months. 3) Peripheral neuropathy usually dose dependent, with different clinical presentations: polyneuritis with sensory, motor, or both deficits, and few cases of tetraplegia. 4) Encephalopathy frequently associated with one of the precedent symptoms, having a favorable outcome (probably resulting in inhibition of dopamine-beta-hydroxylase by disulfiram). The mechanism of toxicity (direct or idiosyncractic) remain unclear. Disulfiram has been used safely in millions of people since 1948, and we have only few cases reports of severe toxicity. From a practical point of view, treated patients should benefit by a neurological examination once a month, ophtalmological examination every 2 months, and hepatic enzymes monitored twice a month during the 2 first months. This is the price to prevent and to detect side effects of disulfiram therapy.

Adult↗
PubMed1995

DNA analysis as a tool to confirm the diagnosis of asymptomatic hereditary neuropathy with liability to pressure palsies (HNPP) with further evidence for the occurrence of de novo mutations.

We performed DNA analysis in four families with hereditary neuropathy with liability to pressure palsy (HNPP). An interstitial deletion of the 17 p11.2 region was found in typically affected patients as well as in as yet asymptomatic patients. The opportunity for an individual genotyping permitted to ascertain a de novo deletion in one clinically affected case with no relevant familial history. DNA analysis thus becomes the most sensitive tool in diagnosing HNPP, since potentially affected patients may lack either informative familial history, or clinical symptoms or even suggestive EMG or histopathological data (tomaculas).

Adolescent↗
PubMed1995

Unilateral upper limb asterixis related to primary motor cortex infarction.

BACKGROUND: Unilateral upper limb asterixis related to cortical infarct is an unusual clinical picture. We found this association in two patients. Magnetic resonance imaging (MRI), somatosensory evoked potentials (SEPs), and electromyographic recording were performed. CASE DESCRIPTIONS: Two patients developed an acute upper limb ataxia with asterixis. This consisted of frequent arrhythmic loss of extensor muscle tone on instruction to maintain the wrist and fingers extended. Voluntary electromyographic activity in the left extensor digitorum communis muscle showed abrupt periods of interruption ranging from 90 to 260 milliseconds in duration in the first case and from 60 to 220 milliseconds in the second case. SEPs were normal. MRI disclosed a right cortical infarct within the primary motor cortex in both cases. CONCLUSIONS: These findings indicate that asterixis was not related to a failure in the processing of proprioceptive input controlling the regulation of postural tone of the distal upper limbs because SEPs were normal. The involvement of primary motor cortex might suggest that asterixis results from an impairment of a centrally generated motor-command signal controlling the postural tone of the distal upper limb.

Aged↗
PubMed1994

Creatine kinase compactness and thiol accessibility during sodium dodecyl sulfate denaturation estimated by resonance energy transfer and 2-nitro-5-thiocyanobenzoic acid cleavage.

We have investigated the effect of increasing sodium dodecyl sulfate (SDS) concentrations on rabbit muscle cytosolic creatine kinase structure by two methods. We have first determined the variation of accessibility of the thiol groups of the enzyme during SDS denaturation by a technique which involves an irreversible chemical modification of CK accessible thiol groups, followed by NTCB cleavage before the unmodified cysteines in 8 M urea (pH 9) and analysis of the peptides obtained by resolutive gel electrophoresis, without sequencing. We have determined that the order of accessibility of CK MM cysteine residues during SDS denaturation is Cys-282, Cys-145 and then Cys-253. The fourth cysteine residue, Cys-73, is never titrated even at high SDS/CK molar ratio. In contrast, the three last residues are simultaneously titrated when CK is denatured in guanidinium chloride. Thus, SDS-denatured CK seems to retain some residual organized structure. In order to confirm this hypothesis, compactness of the molecule was estimated by fluorescence energy transfer between CK tryptophans and AEDANS, an extrinsic fluorophore. The location of this fluorophore on the accessible thiol of Cys-282 was verified by the previous technique. The results of these experiments do indicate that SDS-denatured CK is more compact than CK completely unfolded in guanidinium chloride.

Animals↗
PubMed1994

Facial motor responses evoked by direct electrical stimulation of the trigeminal root. Localizing value for radiofrequency thermorhizotomy.

In Sweet's description of RF-thermocoagulation for trigeminal neuralgia, the trigeminal nerve was stimulated at 50 c/s to evoke paraesthesias, in order to check the electrode location before the thermolesion is made. In 1979, we changed the frequency to 5 c/s, so as to produce in addition twitches in the masticatory muscles (in stead of the less detectable tetanization produced by 50 c/s stimulation). Since then, we started to observe, also, twitches in the muscles innervated by the facial nerve. These twitches were not always in the Orbicularis oculi (which corresponds to the classical blink reflex), but also in the lower facial muscles. Such clinically observable evoked motor responses (EMR)-which had not been reported before--were noticed in 44% of the 459 procedures performed from 1979 to 1988. When EMR were present, the threshold to evoke paraesthesias before thermolesion, and the duration of the thermolesion for obtaining a marked hypoaesthesia covering the entire painful territory, were significantly lower, respectively p < 0.01 and p < 0.001, than when EMR were absent. This indicates that the electrode was closer to the nerve when EMR were present. As a probable consequence, recurrence of pain was significantly lower in the EMR (+) group: 1.4%, than in the EMR (-) group: 5.8% (p < 0.05). The twitches corresponded to the territory of the evoked paraesthesias in 95%, and to the hypoaesthetic area created by the thermolesion in 96%. So, getting EMR in the territory of the pain can be a helpful indicator for an accurate location of the electrode in the trigeminal root, according to its somatotopic organization. These EMR are hypothesized to be due to a trigemino-facial reflex. A preliminary intra-operative EMG study clearly shows that for EMR in the upper part of the face we are dealing with blink-like reflexes, whilst for EMR in the lower face, mechanisms still remain unclear and need further study to be understood.

Adult↗
PubMed1994

Carpal tunnel syndrome in Mucopolysaccharidoses. A report of four cases in child.

Carpal tunnel syndrome (CTS) is very uncommon in childhood. Sixty-five cases are reported in the literature, principally due to metabolic diseases. In Mucopolysaccharidoses, prospective studies (Wraith and Alani, 1990) found a bilateral CTS in about 90%. We report four cases of Mucopolysaccharidoses, diagnosed on clinical and biological data (two cases of Hurler disease, and two cases of Hunter disease), in children aged less than five years. Each child had claw hands, without thenar atrophy. Median nerve conduction studies and electromyography confirm the CTS. Motor and sensory nerve conductions are normal in other nerves. Concentric needle studies show in two cases, on abductor pollicis brevis, spontaneous activities as repetitive discharges, fasciculations and multiplets. Median nerve stimulations reveal responses with late potentials during 70 ms due to reinnervation. The physiopathology of those carpal tunnel syndromes is discussed.

Action Potentials↗
PubMed1993

Functional domains on chemically modified tau protein.

1. Neurofibrillary tangles present in Alzheimer's disease and, in a lower proportion, in aged brains are formed mainly by paired helical filaments. The microtubule-associated protein tau is a major structural component of these filaments. In order to increase our understanding of the aberrant behaviour of tau protein leading to its assembly into paired helical filaments, studies were carried out using chemical modifications of brain tau protein. 2. Selective carbamoylation of tau with KCNO resulted in an irreversible modification of lysine residues on tau protein. The capacity of chemically modified tau protein to induce tubulin assembly, under standard in vitro microtubule polymerization conditions, decreased gradually in relation to the increase in concentration of the modifying reagent. 3. Interestingly, carbamoylated tau protein exhibited the capacity to self-assemble into polymeric structures resembling those of paired helical filaments, after incubating the modified protein at concentrations higher than 1.0 mg/ml, at 37 degrees C with KCNO. 4. The nature of polymers obtained from cabamoylated tau protein was analyzed by ultrastructural studies. The data provide new clues toward our understanding of the anomalous interactions of tau in Alzheimer's disease.

Acylation↗
PubMed1993

A tau-like protein interacts with stress fibers and microtubules in human and rodent cultured cell lines.

The cytoskeletal integrity of human and rodent cell lines was analyzed using site-directed monoclonal antibodies prepared from hybridomas. Secreting hybridomas were produced by immunizing mice with synthetic peptides from the C-terminal domain of the beta II-tubulin isotype, beta II(422-434), YQQYQDATADEQG, and the first imperfect repeat from brain tau, Tau-I(187-204), VRSKIGSTENLKHQPGGG. Two hybridomas were selected for this work: MTB6.22, an anti-idiotypic monoclonal antibody, which was obtained from a mouse immunized with the beta II-peptide and recognizes specific tubulin-binding domains on MAP-2 and tau; and Tau-I/1, which recognizes the repetitive binding sequences on tau and MAP-2. Immunoblots of cytoskeletal protein preparations from the five different tumor cell lines studied, showed the interaction of the site-directed antibodies MTB6.22 and Tau-I/1 with a group of proteins that co-migrate with brain tau. Immunoreactive tau components were also identified using an anti-tau monoclonal antibody (clone Tau-2), and several polyclonal anti-tau antibodies that interact with tau epitopes, other than those of the tubulin-binding domains. These tau-like proteins bound to a calmodulin-Sepharose affinity column and were eluted using 2 mM EGTA. Interestingly, washing the extracted cytoskeleton pellet with 5 x 10(-3) M Ca2+ for short periods of time selectively released the tau-like protein components, whilst most of the other cytoskeletal proteins remained in the pellet. On the other hand, immunofluorescence microscopy of detergent-extracted cells showed immunostaining of MAP components that appear to be co-localized in a discrete dot-like distribution along the stress fibers, which were revealed using rhodamine-phallacidin. Further support for the specificity of tau interaction with sites on tubulin and actin polymers was obtained with double-immunofluorescence, using the MAP-reactive monoclonal antibody MTB6.22 and a polyclonal antibody to a tubulin peptide containing part of the tau-binding domain on tubulin. Considering the anti-idiotypic nature of the MTB6.22 monoclonal antibody, our studies indicate that, in all the cell lines analyzed, a tau-like protein component is involved in mediating the interaction of both actin and tubulin polymers.

Actins↗
PubMed1993

[Neurological complications caused by gold salts. Nosologic report apropos of a case].

Gold therapy is responsible for many neurological complications. We report a case presenting with the clinical and electrophysiological characteristics of neuromyotonia, polyradiculoneuritis and Morvan's fibrillary chorea. The various neurological complications of gold therapy and the possible relationships between these different syndromes are discussed.

Antirheumatic Agents↗
PubMed1993

[Paralysis of abdominal muscles caused by Lyme disease].

A 67-year old patient with meningoradiculitis due to Borrelia Burgdorferi presented with unilateral trunk dysesthesias and severe asymmetrical abdominal distension. The causes of abdominal wall paralysis are reviewed.

Abdominal Muscles↗
PubMed1993

[Ataxic monoparesis of the upper limb and suspension of the tonus caused by parietal lesion].

A 58-year old right-handed man with chronic non valvular atrial fibrillation developed an acute left upper limb ataxia with transient numbness and mild motor impairement. Two weeks later, there was a severe degree of ataxia of the left upper limb and prominent asterixis of the left hand. CT scan and MRI showed a small parietal infarct. Initial median nerve somatosensory evoked potentials (SEPs) showed mild impairement of right parietal responses with absent right frontal SEPs P22 and N30. Two months later, parietal responses were normal but right frontal SEPs P22 and N30 remained abolished while ataxia of left upper limb persisted. Electromyographic activity recorded at the same time showed periodic involvement of the left hand distal tonus. These finding suggested that both ataxia and asterixis were due to a single postcentral infarct. Frontal SEP components are known to convey proprioceptive inputs which could be received by neocerebellar afferent pathways. Generators of these components are presumably located in premotor cortex and can be activated through parietofrontal connections. In our case it can be assumed that the parietal infarct involved these connections, which are mainly implied in the regulation of postural tonus of the distal upper limbs, and simultaneously impaired neocerebellar afferent pathways resulting in the emergence of parietal ataxia.

Arm↗
PubMed1992

The antineoplastic agent estramustine and the derivative estramustine-phosphate inhibit secretion of interleukin-3 in leukemic cells. Possible roles of MAPs.

The antineoplastic drug estramustine is an adduct of estradiol and nor-nitrogen mustard. It has been shown that this drug interferes with microtubule assembly, an effect mediated by estramustine interaction with microtubule-associated proteins (MAPs). In the present report we demonstrate that estramustine and the phosphorylated derivative of the drug, estramustine-phosphate, inhibit the secretion of interleukin-3 by WEHI-3B cells. These studies also show that the estramustine derivative specifically interacts with a MAPs component found in these cells, which exhibited characteristics ressembling those of tau protein isoforms. Western blots using a unique monoclonal antibody MTB6.22 that recognizes microtubule-binding domains on MAPs, indicated that this WEHI protein factor contained the antigenic determinant that are functionally significant for microtubule assembly. ELISA assays using this antibody, also showed a decrease in the levels of the immunoreactive protein in WEHI cells after treatment with EMP. Interestingly, it has been recently described that the action of estramustine-phosphate is mediated by a direct interaction with MAP-binding sites on the microtubule surface, which are recognized by the site-specific monoclonal antibody. These findings together with immuno-precipitation experiments using anti-interleukin-3 antibodies and the inhibitory effect of the estramustine derivative on WEHI secretion process suggest that this anti-mitotic agent may block IL-3 secretion by a mechanism involving its interaction with a 'tau-like' MAPs component present in these cells.

Animals↗
PubMed1992

Low mitochondrial proton leak due to high membrane cholesterol content and cytosolic creatine kinase as two features of the deviant bioenergetics of Ehrlich and AS30-D tumor cells.

Isolated mitochondria from highly glycolytic Ehrlich and AS30-D tumor cells have a 12.4- and a 2.3-fold higher cholesterol level, respectively, than that of rat liver mitochondria. The passive proton permeability of Ehrlich and AS30-D tumor inner membrane mitochondria is, respectively, 4- and 1.4-fold lower than that of rat liver mitochondrial membrane. This feature is accompanied by a lower proton leak current in tumor mitochondria. A 3.5-fold cholesterol enrichment of rat liver mitochondria decreases their passive proton permeability by a factor of 2, thus establishing a direct relationship between the cholesterol contents of mitochondrial membranes and the passive proton permeability. Creatine kinase activity is present in the cytosol of these cells and is mostly represented by the BB isoform. Since AS30-D tumor cells' treatment with the creatine analogue beta-guanidinopropionic acid decreases their life span and viability, creatinine kinase is an indispensable enzyme entering a main energy distribution pathway starting from mitochondrial ATP, through glycolysis and creatine phosphorylation, to satisfy the large energy demands of tumor cell division.

Animals↗
PubMed1992

Specific macromolecular interactions between tau and the microtubule system.

The microtubule-associated protein Tau, a major component of brain microtubules, shares common repeated C-terminal sequences with the high molecular-weight protein MAP-2. It has been shown that tau peptides V187-G204 and V218-G235, representing two main repeats, induced brain tubulin assembly in a concentration-dependent fashion. The specific roles of these repeats in the interaction of tau with microtubules, and its antigenic nature were investigated using synthetic tau peptides and site-directed monoclonal antibodies. Tau peptides appeared to compete with MAP-2 incorporation into assembled microtubules. The interactions of the tau fragments with beta-tubulin peptides bearing the tau binding domain on tubulin were analyzed by fluorescence spectroscopy. The specificity of the binding was further demonstrated by the reactivity of tau and the tau peptides with a monoclonal anti-idiotypic antibody produced after immunization with the beta-II(422-434) tubulin peptide, as assessed by enzyme-linked immunoassay. Western blots confirmed the interaction of tau with the monoclonal antibody. In addition, immunoassays revealed a competition between the MAP-reacting monoclonal antibody and the tubulin peptide beta-II(422-434) for their interaction with the tau molecule.

Amino Acid Sequence↗