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Duyckaerts C, Hauw JJ, Piette F, Rainsard C, Poulain V, Berthaux P, Escourolle R. Cortical atrophy in senile dementia of the Alzheimer type is mainly due to a decrease in cortical length. Acta Neuropathol 1985; 66:72-4. [PMID: 3993335 DOI: 10.1007/bf00698298] [Citation(s) in RCA: 74] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A prospective study was undertaken to select mentally normal old subjects and patients with senile dementia of the Alzheimer type (SDAT). The test score of Blessed et al. (1968) (BTS) was used to determine the severity of mental impairment. A pathologic study confirmed the diagnosis of either SDAT or normal brain aging at postmortem examination in 12 cases. The cortical area and the cortical perimeter of the different cerebral lobes were measured on 1-cm-thick coronal sections using a semiautomatic image analyzer. Cortical length and thickness were calculated using perimeter and area values. BTS was significantly correlated with both the area (r = 0.7695, P = 0.003) and the length (r = 0.7421, P = 0.006) of the temporal cortex. There was no significant correlation between BTS and thickness of the temporal cortex (r = 0.559, P = 0.059). These results show that reduction of length is one of the major determinants of cortical atrophy. Although this has to be confirmed by histological study, they favor the hypothesis of a column-selective atrophy in SDAT which should be considered in the interpretation of the microscopic data.
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Duyckaerts C, Sluse-Goffart CM, Sluse FE, Gosselin-Rey C, Liébecq C. Spontaneous modification of the oxoglutarate translocator in vivo. Eur J Biochem 1984; 142:203-8. [PMID: 6745271 DOI: 10.1111/j.1432-1033.1984.tb08272.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In studying the oxoglutarate translocator of rat-heart mitochondria over many years, we have observed an unexpected decrease in its efficiency. It has been divided by 2.48 +/- 0.07, (S.E.M.) for the exchange of external oxoglutarate for internal malate at 2 degrees C when the internal-malate concentration is 4 mM and is accompanied by an increase in its concentration (multiplied by 1.61 +/- 0.02, S.E.M.). The affinity of the external sites of the translocator for the external oxoglutarate is unchanged as well as the binding and kinetic cooperativities of the external oxoglutarate. This shows that the external side of the translocator has not been modified and suggests that its central part has not been modified either. The apparent Michaelis constant of the internal malate is increased (multiplied by 1.74 +/- 0.23, S.E.M.) suggesting that the translocator has been modified on its matricial side. Some control experiments show that a change in the diet of the rats, despite its effect on the fatty-acid content of the mitoplasts, is probably not responsible for the observed modification. As it is nevertheless very likely that changes of the oxoglutarate translocator have occurred in vivo, it is proposed that the observed modification has a genetic origin. The existence of two antagonist changes which are not directly related suggests that one of them is a response of the organism against the other; thus the oxoglutarate translocator may play a regulatory rôle in certain physiological conditions.
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203
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Duyckaerts C. [Anatomy of the spinal cord]. Soins 1984:3-5. [PMID: 6564735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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204
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Sluse-Goffart CM, Sluse FE, Duyckaerts C, Richard M, Hengesch P, Liébecq C. Conformational changes and possible structure of the oxoglutarate translocator of rat-heart mitochondria revealed by the kinetic study of malate and oxoglutarate uptake. Eur J Biochem 1983; 134:397-406. [PMID: 6884340 DOI: 10.1111/j.1432-1033.1983.tb07581.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Initial rates of the exchanges [14C]malateout:malatein, ([14C]oxoglutarate + malate)out:malatein and ([14C]malate + oxoglutarate)out:malatein catalysed by the oxoglutarate carrier of rat-heart mitochondria have been studied under conditions where internal and external substrates may be varied. It is shown that contrary to external oxoglutarate which induces a conformational change of the translocator subunit to which it binds, external malate does not induce conformational changes during its binding and is a Michaelian substrate. The study of the effect of external malate on the rate of oxoglutarate uptake shows that external malate and external oxoglutarate are competitive. External oxoglutarate affects the catalytic rate constant of malate uptake in a modulated way. After substrate binding, the exchange reaction between an external dicarboxylate and an internal dicarboxylate is accompanied by conformational changes. The particular form of the rate equation strongly suggests that during a first step the external substrate bound to an external binding subunit at the external surface of the membrane, and the internal substrate bound to an internal binding subunit at the internal surface of the membrane, are transferred to a catalytic subunit (channel?) deeper in the membrane. Two models, one with a single channel, and the other with several associated channels, are proposed. It is demonstrated that a binding subunit which has transferred its substrate to a catalytic subunit is left in a conformation which does not depend on the substrate that has 'passed through it'. It is also demonstrated that all the catalytic subunits are identical. These theoretical deductions allow a simple description of the complicated effect that external oxoglutarate has on the rate of malate uptake. The fact that all the external binding subunits are equivalent regarding external malate binding and that all the catalytic subunits are identical support the view that the mitochondrial preparation contains a single species of oxoglutarate translocator and not an isozymic mixture.
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Abstract
Two cases of fatal encephalopathy which appeared in the course of treatment of malignant gliomas are described. CT scan showed diffuse, low density, non-enhanced lesions of the white matter. Pathological findings showed that the CT scan aspects corresponded to status spongiosus without demyelination. We were unable to find similar reports in the literature.
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Frère JM, Dormans C, Duyckaerts C, De Graeve J. Interaction of beta-iodopenicillanate with the beta-lactamases of Streptomyces albus G and Actinomadura R39. Biochem J 1982; 207:437-44. [PMID: 6299270 PMCID: PMC1153883 DOI: 10.1042/bj2070437] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The beta-lactamases of Streptomyces albus G and Actinomadura R39 are inactivated by beta-iodopenicillanate. However, in contrast with the beta-lactamase I from Bacillus cereus, they also efficiently catalyse the hydrolysis of the inactivator; with the S. albus G enzyme, kcat. is larger than 25s-1 and the number of turnovers before inactivation is 515. With the A. R39 enzyme, kcat. is larger than 50s-1 and the number of turnovers before inactivation is 80. After hydrolysis of the beta-lactam amide bond, the product rearranges into 2.3-dihydro-2,2-dimethyl-1,4-thiazine-3,6-dicarboxylate, which exhibits an absorption maximum at 305 nm.
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207
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Frère JM, Dormans C, Lenzini VM, Duyckaerts C. Interaction of clavulanate with the beta-lactamases of Streptomyces albus G and Actinomadura R39. Biochem J 1982; 207:429-36. [PMID: 6984651 PMCID: PMC1153882 DOI: 10.1042/bj2070429] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The reactions of beta-lactamases of Actinomadura R39 and Streptomyces albus G with clavulanate proceed along branched pathways. Both enzymes perform the hydrolysis of this beta-lactam with rather high efficiencies (kcat. = 18s-1 and 52s-1 respectively). If large clavulanate/enzyme ratios are used, complete inactivation of the enzymes is observed. At lower ratios, inactivation is only partial. Irreversible inactivation occurs after 400 and 20000 turnovers for the A. R39 and S. albus G enzymes respectively. With the A. R39 beta-lactamase, a transiently inhibited complex is also formed that remains undetectable with the S. albus G beta-lactamase. Kinetic models are presented and studied for the interaction between clavulanate and both enzymes. A tentative general reaction scheme is also discussed.
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208
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Castaigne P, Lhermitte F, Buge A, Pertuiset B, Hauw JJ, Duyckaerts C. [Clinical symptoms and anatomical locations in primary haemorrhages of the basal ganglia. A neuropathological study of 64 cases (author's transl)]. Nouv Presse Med 1981; 10:2803-11. [PMID: 7312591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The signs, symptoms and courses of 64 cases of "primary" haematoma of the basal ganglia have been retrospectively studied, and the main clinical data have been analyzed in relation to the location and extent of the bleeding. Onset with hemiplegia, accompanied or not by impaired consciousness, was more frequent with intermediate and lateral haematomas than with medial haematomas (p less than 0.001). Among patients with initial hemiplegia, impaired consciousness was more frequent with intermediate and medial haematomas than with lateral haematomas (p less than 0.005). At a later stage, patients with intermediate and lateral haematomas more often went into deep coma than those with medial haematomas (p less than 0.01). There were no statistically significant differences between the three anatomical groups with regard to frequency of other signs and symptoms or duration of the disease before death occurred.
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Ben Hamida M, Marzouki M, Duyckaerts C, Samoud S. [Dacrystic epilepsy. A case]. Nouv Presse Med 1980; 9:2019-20. [PMID: 7402904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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211
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Duyckaerts C, Sluse-Goffart CM, Fux JP, Sluse FE, Liebecq C. Kinetic mechanism of the exchanges catalysed by the adenine-nucleotide carrier. Eur J Biochem 1980; 106:1-6. [PMID: 6280992 DOI: 10.1111/j.1432-1033.1980.tb05990.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Initial rates of the exchange ADPin/ADPout catalysed by the adenine-nucleotide carrier of rat-heart mitochondria have been studied under conditions where internal and external ADP may be varied. The initial rate was measured within 1 s by the carboxyatractyloside-stop method, using a rapid-mixing technique. The double-reciprocal plots v0(-1) versus [ADP]out-1 at different internal-ADP concentrations and v0(-1) versus [ADP]in-1 at different external-ADP concentrations exhibit straight-line relationships having a common point of intersection on the axis of ordinates. These results demonstrate the essential role of a ternary complex and thus exclude the ping-pong mechanism generally accepted. The kinetic equation implies a strong positive cooperativity in the binding of the two substrates. Two models are proposed: (a) the ternary complex performs the exchange and the transport of the substrates in a single step; (b) the carrier is mobile and transports the substrates one by one, the formation of a ternary complex being needed to release the first product.
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212
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Sluse FE, Duyckaerts C, Liébecq C, Sluse-Goffart CM. Kinetic and binding properties of the oxoglutarate translocator of rat-heart mitochondria. Eur J Biochem 1979; 100:3-17. [PMID: 488098 DOI: 10.1111/j.1432-1033.1979.tb02028.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The kinetic study of the oxoglutarateout/malatein exchange through the inner mitochondrial membrane of rat-heart mitochondria has been compelted and extended to higher external-oxoglutarate and to lower internal-malate concentrations. It has been found that the external oxoglutarate inhibits the exchange at high concentration. This excess-substrate inhibition is preceded by four jumps. The kinetic-saturation curve by the internal malate presents an apparent positive cooperativity that may be interpreted in different ways. The independence of the effects of the two substrates on the initial rate has been observed again and supports the conclusions reached in previous work. A method for the determination of oxoglutarate binding to the external face of the inner membrane is described. The binding curve shows four intermediary plateau regions that reflect significant apparent K-effects, alternatively negative and positive. For external-oxoglutarate concentrations below the region of excess-substrate inhibition, the binding-saturation curve and the kinetic-saturation curve are similar, demonstrating that K-effects are predominant. A particularly wide intermediary plateau that seems to correspond to half saturation of the active sites is common to both saturation curves. A clear lack of proportionality between the two curves at low oxoglutarate concentrations seems to indicate that more than one catalytic-rate constant is implied in the exchange kinetics. Two models of the oxoglutarate carrier are presented. Both lead to a minimum degree of 10:10 for the equation of the binding of oxoglutarate to the catalytic sites. In the first model this corresponds to ten subunits associated into a single oligomer while in the second model this results from a mixture of monomeric, dimeric, trimeric and tetrameric associations.
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213
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Fux JP, Sluse FE, Sluse-Goffart C, Duyckaerts C, Liébecq C. [Relations between oxoglutarate transport function and variations of space in rat heart mitochondria (proceedings)]. Arch Int Physiol Biochim 1979; 87:411-2. [PMID: 92958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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214
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Sluse FE, Sluse-Goffart C, Duyckaerts C, Liébecq C. [Fixation of oxoglutarate on the external face of the internal minochondrial membrane of rat hearts (proceedings)]. Arch Int Physiol Biochim 1978; 86:887-8. [PMID: 84597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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215
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Sluse FE, Duyckaerts C, Sluse-Goffart C, Liébecq C. [The kinetics of oxoglutarate transport in rat heart mitochondria (proceedings)]. Arch Int Physiol Biochim 1978; 86:886-7. [PMID: 84596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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216
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Sluse FE, Duyckaerts C, Sluse-Goffart C, Fux JP, Liébecq C. [Kinetic study of the transport of adenine nucleotides into rat heart mitochondria (proceedings)]. Arch Int Physiol Biochim 1978; 86:888-9. [PMID: 84598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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217
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Sluse FE, Sluse-Goffart CM, Duyckaerts C, Liébecq C. Evidence for cooperative effects in the exchange reaction catalysed by the oxoglutarate translocator of rat-heart mitochondria. Eur J Biochem 1975; 56:1-14. [PMID: 1175617 DOI: 10.1111/j.1432-1033.1975.tb02201.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The initial rates of the exchange external oxoglutarate/internal malate through the inner membrane of rat-heart mitochondria, for various concentrations of the two substrates, have been reinvestigated for an extended range of concentrations of the external oxoglutarate. This has been made possible by use of the inhibitor-stop technique that allows 100 times smaller incubation times than the centrifugation-stop technique used previously. Under the experimental conditions the uptake of the external-labelled oxoglutarate into the mitochondrial-matrix space is mediated by the oxoglutarate translocator performing a ono-to-one exchange of the anions oxoglutarate (external) and malate (internal). Two intermediary-plateau regions are observed in the kinetic saturation curve of the translocator by the external oxoglutarate, revealing a complex rate equation which is found to be the product of two one-substrate functions. Analysing these features it is shown that the model, proposed earlier, of a "double carrier" as catalyst in a rapid-equilibrium random bi-bi mechanism, is still applicable but that several external binding sites have to be considered. As already noticed the external and the internal substrates bind to their respective sites independently of each other. Furthermore, some additional requirements imposed by the observed kinetics suggest that the exchange reaction is performed by only one translocator species made of identical interacting subunits. The anion exchange is tentatively viewed as a rotation of a subunit around an axis situated in the plane of the membrane after two independent local configuration changes induced by the binding of the two substrates on this subunit.
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Duyckaerts C. [Role of catecholamines in hypoxia and hyperglycemia induced by injection of cystamine]. Arch Int Pharmacodyn Ther 1971; 191:400-4. [PMID: 4397370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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219
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Duyckaerts C, Bleiman C, Winand-Devigne J, Liébecq C. [Oxido-reduction potential of blood from rats and mice injected with cystamine]. Arch Int Physiol Biochim 1969; 77:374-6. [PMID: 4184327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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220
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Duyckaerts C, Schoffeniels E. [Binding of nicotinamide adenine dinucleotide to glutamate dehydrogenase]. Arch Int Physiol Biochim 1966; 74:895-903. [PMID: 4165986 DOI: 10.3109/13813456609059963] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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