Jacques De Reuck

Diquat intoxication: Report of two cases and review of the literature

Animal experiments have suggested that diquat is less toxic than the more widely used paraquat. In this paper, nine previously reported cases of diquat intoxication are reviewed, together with the description of our personal observations in two additional patients. These two patients, like four other patients described in the literature, died from complications involving the gastrointestinal tract, brain and kidneys. Thus, diquat intoxication is apparently not as innocent as was originally thought. In this paper, special attention has been given to the major clinical differences between diquat and paraquat intoxication. In contrast with the latter, severe diquat intoxication induces gastrointestinal fluid sequestration and is associated with cerebral hemorrhagic lesions and a higher incidence of severe acute renal failure. Despite an asymptomatic clinical interval of up to 48 hours after ingestion, hemoperfusion should be started as soon as possible to prevent toxic levels of diquat in tissue.

Psychoacoustical Deficits Related to Bilateral Subcortical Hemorrhages a Case with Apperceptive Auditory Agnosia

We report a case of acute deafness secondary to bilateral hemorrhages involving the external capsule and extending to both temporal isthmi. The lesions probably disrupted both auditory radiations. Deafness disappeared within 2 weeks leading to a transient auditory agnosia for environmental and verbal sounds. Performance on audiological and neurolinguistic tests were consistent with the hypothesis of a deficit of non-specific auditory processes. Psychoacoustical deficits related to subcortical lesions are very rare and might differ from those due to cortical lesions by the lack of aphasia. The present case and both previous cases with subcortical lesions might suffer from auditory agnosia of apperceptive type. Its characteristics and the role of non-specific auditory processes are discussed using the data obtained from this third case.

55Cobalt (Co) as a PET-tracer in stroke, compared with blood flow, oxygen metabolism, blood volume and gadolinium-MRI

Several studies have shown the feasibility of divalent cobalt (Co)-isotopes (55Co and 57Co) in imaging of neuronal damage in stroke, multiple sclerosis, cerebral tumors and traumatic brain injury. Little is known how regional Co uptake relates to other pathophysiological changes after stroke. Therefore, we compared 55Co-PET with functional parameters such as regional cerebral blood flow (rCBF) using C(15)O(2), regional oxygen metabolism (rCMRO(2)) using 15O(2), regional cerebral blood volume (rCBV) and post-gadolinium (Gd) T(1)w-MRI to assess the permeability of the blood-brain-barrier (BBB). Sixteen patients (10 female; six male) aged 43 to 84 (mean 69) years with first ever stroke, as shown by CT or MRI, were examined with 55Co-PET and C(15)O(2)-, 15O(2)- and C(15)O-PET in one single session, in a period varying from 0 to 30 days after stroke-onset. Regions of infarction on C(15)O(2)- and 15O(2)-PET (defined by rCMRO(2)<65% or rCBF<45% of the contralateral value) were subsequently superimposed on the 55Co-PET scan. Clinical status was established using the Orgogozo stroke scale, which was assessed both at day 1 and at discharge (at least 6 weeks after day 1). Accumulation of 55Co was seen in eight out of 16 patients, occurring in areas showing a diminished oxygen metabolism, was only partially related to blood flow, and was located mainly outside the extent of the infarction or luxury perfusion as seen on post-Gd T(1)w-MRI. Statistical analysis showed a negative correlation between the Orgogozo score at discharge and the uptake of radioactive cobalt.

Application of principal component and cluster analysis to the study of the distribution of minor and trace elements in normal human brain

Abstract Duflou, H., Maenhaut, W. and De Reuck, J., 1990. Application of principal component and cluster analysis to the study of the distribution of minor and trace elements in normal human brain. Chemometrics and Intelligent Laboratory Systems , 9: 273–286. A data set with the K, Ca, Mn, Fe, Cu, Zn, Se, and Rb concentrations for 46 brain structures of gray, mixed, or white brain matter was subjected to VARIMAX rotated absolute principal component analysis (APCA) and hierarchical cluster analysis. APCA indicated that most of the K, Cu, Zn, Se, and Rb is present in the intracellular brain fluid. Calcium is mainly associated with the extracellular fluid, while most of the Fe is found in the solid brain fraction. Both the intracellular fluid and the solid brain fraction contribute to the Mn content to a considerable degree. Hierarchical cluster analysis showed that the brain regions conglomerate in two main clusters. All gray matter structures are included in the first cluster; the second cluster comprises all white matter areas. Furthermore, structures involved in the same physiological function or morphologically similar regions often conglomerate in the same subcluster.

High-performance liquid chromatographic determination of [11C]1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide in mouse plasma and tissue and in human plasma

The high-performance liquid chromatographic determination of 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide ([11C]PK 11195) is described. The method was successfully applied for plasma and tissue analysis after i.v. injection of [11C]PK 11195 in mice and for plasma analysis after administration of [11C]PK 11195 to humans. Separation is effected on a RP-C18 column, using a mixture of acetonitrile-water-triethylamine (65:35:0.5, v/v). Quantitative measurements of radioactivity are performed on a one-channel gamma-ray spectrometer equipped with a 2 x 2 in. NaI(Tl) detector. For humans rapid metabolisation of [11C]PK 11195 was observed. At 5, 20 and 35 min post injection 5%, 22% and 32%, respectively, of the plasma activity consisted of at least two more polar metabolites. Despite the extensive metabolisation rate in mice (up to 42% at 10 min post injection of [11C]PK 11195), no 11C-labelled metabolites could be detected in the extracts of brain and heart.

Is the Leuko-Araiosis-Dementia syndrome different from Binswanger's subcortical atherosclerotic encephalopathy?

Binswangers subcortical atherosclerotic encephalopathy is a rare form of multi-infarct dementia. This neuropathologic entity consists of lacunes in the basal ganglia and in the periventricular white matter, surrounded by widespread demyelination (1). The lesions predominate in the periventricular arterial borderzones, which are more vulnerable to ischemia in case of impaired perfusion of the brain (2,3). With the introduction of the new generations of computed tomographic (CT) scanners and of nuclear magnetic resonance (NMR) imaging, hypodensities and signal changes are frequently observed in the deep white matter of aged persons (4,5). This leukoaraiosis is mainly seen in patients suffering from strokes and vascular dementia (6,7), but it is also found in aged persons without clear cognitive dysfunction or suffering from Alzheimers dementia (8-10) . It is suspected to be of ischemic origin based on the high association with lacunar strokes and arterial hypertension (11,12). Increasing cerebral atrophy and advancing age contribute in that order to the presence and the severity of leuko-araiosis (13,14). The questions as to whether or not progressing leuko-araiosis can be responsible for dementia and whether or not the endstage of the leuko-araiosisdementia syndrome represents the morphologic changes of Binswangers subcortical atherosclerotic encephalopathy remain (15-18) . The positron emis-

Effect of neurotropin on cerebral edema, calcium and other elements in mice subarachnoidally injected with carrageenan

Neurotropin, an inhibitor of the kallikrein-kinin system, was therapeutically i.p. administered to mice with brain inflammation induced by subarachnoidal injection of carrageenan. Brain water content was determined by the wet/dry weight ratio. The concentrations of cerebral Ca, K, Mn, Fe, Cu, Zn, Se, Rb, and Sr were measured by particle-induced X-ray emission. It was found that neurotropin dose dependently reduced brain water content. The mean concentration of cerebral calcium was significantly lower in the neurotropin-treated group than that in the non-treated group, suggesting less cell damage. Since it has been reported that dexamethasone and some prostaglandin inhibitors have no effect on brain swelling in this model and that, in contrast to these drugs, neurotropin has only a weak inhibiting activity on carrageenan-induced paw swelling, it is hypothesized that the kallikrein-kinin system is differently implicated in cerebral and peripheral inflammation.

The Topography of Cortical Microinfarcts in Neurodegenerative Diseases and in Vascular Dementia: A Postmortem 7.0-Tesla Magnetic Resonance Imaging Study

Background: Cortical microinfarcts (CoMIs) are considered as barely visible lesions in clinical-neuroradiological correlation studies. On postmortem 7.0-tesla MRI, however, CoMIs of different size are easily detected. Summary: The present MRI study investigates 84 postmortem brains with different neurodegenerative diseases and vascular dementia (VaD) for their topographic distribution and the prevalence of CoMIs. The mean numbers of CoMIs were determined on 6 hemispheric coronal sections and in 22 different gyri with a 7.0-tesla MRI Bruker BioSpin SA. A large coronal section at the level of the mammillary body was also used for neuropathological evaluation. CoMIs were predominantly observed in the prefrontal and postcentral sections of VaD brains. The mean number of CoMIs was significantly increased in the inferior frontal and in the cingulate gyri of VaD brains compared to the controls. No topographic differences were observed in the neurodegenerative diseases. Key Messages: As the inferior frontal and the cingulated gyri are areas frequently involved in VaD, CoMIs in those strategic locations must have an impact on the evolution of the vascular cognitive decline in those patients.

Fetal Chiari’s Type III Malformation

The morphological findings in a 4- to 5-month-old female fetus with Chiaris type III malformation are described. This observation strongly supports the view that a defective closure of the roof plate is the primary cause of this malformation, and relates it to the Arnold-Chiari and Dandy-Walker syndromes.

Cerebral blood flow and oxygen metabolism in symptomatic internal carotid artery occlusion by atherosclerosis and by cervical dissection.

Symptomatic internal carotid artery occlusion by atherosclerosis and by cervical dissection are distinct conditions with different long-term prognoses. The purpose of the present study is to investigate if regional cerebral blood flow and oxygen metabolism, after onset of stroke, differ between both conditions. Seventeen patients with symptomatic unilateral atherosclerotic internal carotid occlusion and 10 patients with symptomatic internal carotid occlusion due to cervical dissection were submitted to a positron emission tomographic (PET) study between 1 and 2 months after stroke onset. The steady state technique with 15O was used in order to determine regional cerebral blood flow, regional oxygen extraction fraction, and regional cerebral metabolic rate for oxygen in the infarct area, the peri-infarct zone, the remaining homolateral hemisphere, and the contralateral hemisphere. The results were compared between both patients populations. The patients with cervical dissection were on average much younger than those with atherosclerotic occlusion, but neurological impairment on admission and disability at 3 months were comparable. Between both patient populations, no differences in rCBF, rOEF, and rCMRO2 could be demonstrated in the different regions of interest when the results were age-adjusted. Except for age-related changes, no differences in PET findings could be demonstrated between patients with symptomatic internal carotid occlusion caused by either atherosclerosis or cervical dissection.