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A Michotte

Publications and source records attributed to A Michotte.

At least 19 recordsLinked to original sources
PubMed2006

Increased incidence of sporadic Creutzfeldt-Jakob disease in the age groups between 70 and 90 years in Belgium.

From 1998 a prospective surveillance study of Creutzfeldt-Jakob disease (CJD) has been initiated in Belgium. In addition to epidemiological data, information on cerebrospinal fluid biomarkers, prion protein gene and brain neuropathology was collected. From 1-1-1998 to 31-12-2004, 188 patients were referred to the surveillance system. In 85 patients a 'definite' diagnosis of sporadic CJD (sCJD) could be made, whereas 26 patients remained 'probable'. We further identified two unrelated patients with an E200K mutation, and two patients with a seven octapeptide repeat insertion in one family. In one patient a familial history was noted but genetic analysis was not performed. In 72 patients different final diagnoses were made, Alzheimer's disease being the most frequent (N = 20). The demographic parameters of the Belgian population were similar to those observed in the rest of Europe. We did notice a significantly increased age-specific incidence (> 6/10(6)/year) of sCJD patients between 70 and 90 years old in the period 2002-2004 compared to 1998-2001 and retrospectively obtained data (1990-1997, p < 0.01). We undertook a detailed clinical and biochemical analysis to investigate this increase but could not identify any reason other than an increased vigilance for the diagnosis. In conclusion, our study identified that in the past sCJD may have been underestimated in patients over age 70 although these patients are both clinically and neurobiochemically similar to the general sCJD phenotype.

Age Distribution↗
PubMed2006

Prognostic value of perfusion-weighted imaging in brain glioma: a prospective study.

OBJECT: Biopsy targeting based on MR imaging alone may fail to identify malignant areas in brain gliomas. Considering the differences in relative Cerebral Blood Volume (rCBV) ratios reported among tumour grades, we evaluated whether perfusion-weighted MR imaging (PWI) could usefully implement the routine preoperative imaging by detecting those areas bearing a higher yield for malignancy to guide the stereotactic biopsy or the surgical removal. CLINICAL MATERIAL AND METHODS: We studied a series of 55 consecutive patients with newly diagnosed brain glioma using both conventional MR imaging and PWI in the preoperative assessment. The pathological diagnosis was established by stereotactic biopsy in 29 cases and by craniotomy in 24 cases. We evaluated the patient survival to detect undergrading. DISCUSSION: Independent from contrast-enhancement, perfusion-weighted MR imaging improved the target selection in stereotactic biopsy guidance and the removal of malignant areas in tumours amenable to surgery. Particularly sensitive to the perfused part of the tumour as to small regional changes, rCBV maps allowed a better detection of malignant areas. The rCBV ratios correlated significantly to the tumour grade and the final outcome (p < 0.01). CONCLUSIONS: We found PWI valuable in the preoperative assessment of brain gliomas, discriminating high from low-grade gliomas. PWI can easily be performed on widely available MR imaging systems as part of the routine imaging of gliomas.

Adolescent↗
PubMed2004

Postischemic mild hypothermia reduces neurotransmitter release and astroglial cell proliferation during reperfusion after asphyxial cardiac arrest in rats.

The present study investigated whether postischemic mild hypothermia attenuates the ischemia-induced striatal glutamate (GLU) and dopamine (DA) release, as well as astroglial cell proliferation in the brain. Anesthetized rats were exposed to 8 min of asphyxiation, including 5 min of cardiac arrest. The cardiac arrest was reversed to restoration of spontaneous circulation (ROSC), by brief external heart massage and ventilation within a period of 2 min. After the insult and during reperfusion, the extracellular glutamate and dopamine overflow increased to, respectively, 3000% and 5000% compared with the baseline values in the normothermic group and resulted in brain damage, ischemic neurons and gliosis. However, when hypothermia was induced for a period of 60 min after the insult and restoration of spontaneous circulation, the glutamate and dopamine overflows were not significantly different from that in the sham group. Histological analysis of the brain showed that postischemic mild hypothermia reduced brain damage, ischemic neurons, as well as astroglial cell proliferation. Thus, postischemic mild hypothermia reduces the excitotoxic process, brain damage, as well as astroglial cell proliferation during reperfusion. Moreover, these results emphasize the trigger effect of dopamine on the excitotoxic pathway.

Animals↗
PubMed2004

Neuropathological and molecular aspects of low-grade and high-grade gliomas.

Gliomas are the most frequent primary brain tumors. They are derived from glial cells of astrocytic, oligodendroglial and ependymal origin. According to the WHO classification of brain tumors gliomas are divided in low-grade (grades I and II) and high-grade (grades III and IV) tumors. Low-grade tumors are well-differentiated, slow-growing lesions. Grade I tumors are well-circumscribed and often surgically curable, whereas grade II tumors are diffuse, infiltrating lesions with a marked potential over time for progression towards a high-grade malignant tumor. The optimal management of low-grade gliomas is still debated. Important prognostic factors such as histology, grade and location of the tumor, age and functional status of the patient, must be taken into consideration to select the most appropriate treatment. Major advances in the molecular genetic assessment of brain tumors and of gliomas in particular have lead to the identification of several molecular markers playing a crucial role in the development of gliomas and in their malignant transformation. Some of those markers were found very useful to assist in the histological diagnosis and to predict survival and response to therapy. A combined deletion of chromosomes arms 1p and 19q can be found in more than 50% of Grade II and III oligodendrogliomas and has been associated with chemosensitivity and a better prognosis. Once limited to the field of research, molecular biology has now entered the daily neuropathological practice and will undoubtedly play an increasing role in future classification and treatment of brain tumors.

Biomarkers, Tumor↗
PubMed2003

Recent developments in the neuropathological diagnosis of Parkinson's disease and parkinsonism.

The diagnosis of Parkinson's disease (PD) is based mainly on clinical criteria. Large clinicopathological studies reveal however a different diagnosis in up to 25% of the cases (Hughes et al., 1992). Recent advances in molecular biology have shown that some proteins, especially tau and alpha-synuclein, play an essential role in the pathogenesis of parkinsonian and dementing disorders. Such diseases are now classified as tauopathies and synucleinopathies. Progressive supranuclear palsy and corticobasal degeneration are the major tauopathies. To the synucleinopathies belong PD, Lewy body dementia and multiple system atrophy. In pathological conditions abnormal proteins will aggregate in neurons and glial cells and form inclusion bodies. Lewy bodies are the hallmark of Parkinson's disease and Lewy body dementia. Identification of these inclusions and other specific lesions in parkinsonian disorders is facilitated by the routine application on formalin fixed brain of immunohistochemistry for alpha-synuclein, tau and ubiquitin. The purpose of this paper is to briefly review and illustrate the value of these new techniques in the postmortem diagnosis of parkinsonian disorders. Neuropathological examination of the brain is however time consuming and immunohistochemistry represents additional costs. As the selection of brain samples for microscopical examination and antibodies for immunohistochemistry depends on the underlying pathology, some clinical information should be provided to the pathologist such as the clinical diagnosis and when indicated the results of brain imaging studies. A close co-operation between the neurologist and neuropathologist is thus essential to select the most appropriate brains for complete neuropathological investigation.

Brain↗
PubMed2001

Meningioma of the fourth ventricle presenting with intermittent behaviour disorders: a case report and review of the literature.

Intraventricular meningiomas are rare, representing 0.5-5% of all intracranial meningiomas. They arise mostly within the lateral ventricles and more rarely in the third ventricle. Meningiomas of the fourth ventricle are exceptional. They are clearly defined as meningiomas arising from the choroid plexus and lying strictly within the fourth ventricle. We report a 76 year old male patient presenting with a 2-week history of headache and cognitive disorders with agitation and restlessness particularly exacerbated at night or when lying down. CT scan and MR imaging showed a contrast-enhancing lesion located purely within the whole fourth ventricle, with slight ventricular enlargement. At surgery, we totally removed a well-vascularised, greyish encapsulated mass attached to the choroid plexus. Pathological examination revealed a WHO grade I fibroblastic meningioma. We reviewed the literature concerning this unusual meningioma location.

Aged↗
PubMed2001

Diffusion-weighted MR imaging of intracerebral masses: comparison with conventional MR imaging and histologic findings.

BACKGROUND AND PURPOSE: The purposes of this study were to find the role of diffusion-weighted MR imaging in characterizing intracerebral masses and to find a correlation, if any, between the different parameters of diffusion-weighted imaging and histologic analysis of tumors. The usefulness of diffusion-weighted imaging and apparent diffusion coefficient (ADC) maps in tumor delineation was evaluated. Contrast with white matter and ADC values for tumor components with available histology were also evaluated. METHODS: Twenty patients with clinical and routine MR imaging/CT evidence of intracerebral neoplasm were examined with routine MR imaging and echo-planar diffusion-weighted imaging. The routine MR imaging included at least the axial T2-weighted fast spin-echo and axial T1-weighted spin-echo sequences before and after contrast enhancement. The diffusion-weighted imaging included an echo-planar spin-echo sequence with three b values (0, 300, and 1200 s/mm(2)), sensitizing gradient in the z direction, and calculated ADC maps. The visual comparison of routine MR images with diffusion-weighted images for tumor delineation was performed as was the statistical analysis of quantitative diffusion-weighted imaging parameters with histologic evaluation. RESULTS: For tumors, the diffusion-weighted images and ADC maps of gliomas were less useful than the T2-weighted spin-echo and contrast-enhanced T1-weighted spin-echo images in definition of tumor boundaries. Additionally, in six cases of gliomas, neither T2-weighted spin-echo nor diffusion-weighted images were able to show a boundary between tumor and edema, which was present on contrast-enhanced T1-weighted and/or perfusion echo-planar images. The ADC values of solid gliomas, metastases, and meningioma were in the same range. In two cases of lymphomas, there was a good contrast with white matter, with strongly reduced ADC values. For infection, the highest contrast on diffusion-weighted images and lowest ADC values were observed in association with inflammatory granuloma and abscess. CONCLUSION: Contrary to the findings of previous studies, we found no clear advantage of diffusion-weighted echo-planar imaging in the evaluation of tumor extension. The contrast between gliomas, metastases, meningioma, and white matter was generally lower on diffusion-weighted images and ADC maps compared with conventional MR imaging. Unlike gliomas, the two cases of lymphomas showed hyperintense signal on diffusion-weighted images whereas the case of cerebral abscess showed the highest contrast on diffusion-weighted images with very low ADC values. Further study is required to find out whether this may be useful in the differentiation of gliomas and metastasis from lymphoma and abscess.

Adult↗
PubMed2001

Frontotemporal dementia: a clinical-pathological study.

We report a 44-year-old female patient without any familial history of dementia presenting with increasing disturbances in behaviour and language followed by a progressive cognitive deterioration. Neuropsychological evaluation revealed a significant impairment on frontal lobe tests. A brain PET scan disclosed a severe frontal hypometabolism. The tentative diagnosis of frontotemporal dementia was made. Her condition rapidly worsened and she died 2 years after the beginning of her disease. Gross examination of the brain showed a selective symmetrical atrophy of both frontal and anterior part of the temporal lobes. Microscopical examination revealed severe neuronal loss in the frontal and anterior temporal cortex associated with gliosis and microvascular spongiosis in the superficial cortical layers in the absence of any specific neuronal or glial inclusions. These neuropathological findings were consistent with the diagnosis of dementia lacking distinctive histology. We discuss the nosology of the frontotemporal dementias, the diagnostic value of PET scan, the recent genetical developments which strongly support the pathogenic role of tau and we emphasize the importance of immunohistochemical examination for a definite neuropathological diagnosis.

Adult↗
PubMed1997

Calcified, cystic brain metastases.

Calcifications are uncommon in metastases. Adenocarcinoma, osteopenic, osteosarcoma, lung and breast carcinoma can be the origin. A rare case of calcified cystic brain metastasis deriving from papillary cystadenocarcinoma is reported.

Aged↗
PubMed1997

Impairment of smooth pursuit in pontine lesions: functional topography based on MRI and neuropathologic findings.

Eye movements were studied in two patients with pontine lesions identified by magnetic resonance imaging in one patient and computerized tomography, with neuropathological correlation in another patient. Impairment of ipsilateral saccades were explained by unilateral lesion of the paramedian pontine reticular formation. Ipsilateral dorsolateral and lateral pontine nuclei lesions results in unilateral impairment of smooth pursuit. Bilateral damage to the dorsomedian pontine nuclei result in bidirectional horizontal smooth pursuit deficit, predominantly towards the more pathologic affected side. In addition, these bilateral lesions may also account for impairment of vertical smooth pursuit. These findings confirm that pontine nuclei are an important relay for horizontal and vertical smooth pursuit movements.

Aged↗
PubMed1996

A rare case of diplopia: medial inferior pontine syndrome or Foville's syndrome.

A case of medial inferior pontine syndrome or Foville's syndrome is described. The patient presented to the emergency department with an acute history of slurred speech, vertigo and diplopia as major complaints. He also mentioned the appearance of weakness and numbness in his left leg. The physical examination revealed a crossed neurological deficit (ipsilateral cranial nerve deficit with contralateral motor weakness) which is typical for posterior circulation stroke in the brainstem territory. In our patient the lesion was located in the right medial inferior pontine region. All the symptoms and signs disappeared within 24 hours confirming the importance of a detailed physical and neurological examination of each patient presenting at the emergency department with a neurological deficit.

Aged↗
PubMed1995

Expression of pituitary adenylate cyclase activating polypeptide and receptors in human brain tumors.

The capacity of brain tumor samples to synthesize pituitary adenylate cyclase activating polypeptide (PACAP) was evaluated by the reverse transcriptase-polymerase chain reaction technique (RT-PCR). The expression of PACAP receptors was assessed by a combination of RT-PCR techniques, conventional binding techniques, and also by the ability of PACAP to stimulate adenylate cyclase activity. A weak PACAP mRNA and PACAP receptor mRNA expression was detected in only 3 of 16 meningiomas. A weak PACAP-stimulated adenylate cyclase activity (+20%) was detected in 10 of the 16 samples but binding of labeled PACAP was never observed. In the 16 gliomas studied (including two oligodendrogliomas and two ependymomas), PACAP mRNA was identified in 13 samples and PACAP receptor mRNA in 15 samples. PACAP receptors were identified in all the samples by binding studies and/or by PACAP stimulation of the adenylate cyclase activity. PACAP mRNA was never detected in pituitary adenomas (three prolactinomas, two mixed PRL-GH-producing tumors, three GH-secreting tumors, three gonadotrophinomas, one ACTH-producing tumor, two nonsecreting tumors) whereas PACAP receptor mRNA was highly expressed in all the tumors except prolactinomas, where it was at the limit of detection, confirming the binding and adenylate cyclase activation results. Thus, it is unlikely that the neuropeptide PACAP could influence meningioma's cell growth; PACAP secreted from extratumoral areas may influence pituitary tumors and PACAP could participate to gliomas development.

Adenoma↗
PubMed1995

Intracranial facial nerve rhabdomyoma. Case report.

Nerve rhabdomyomas are exceedingly rare benign tumors of the peripheral nerves consisting of well-differentiated striated muscle fibers admixed with parental nerve fibers. Only one case of intracranial nerve rhabdomyoma has been described, which affected the trigeminal nerve. This report presents the detailed neuropathological description of a nerve rhabdomyoma arising in the schwannian portion of the facial nerve root in a 41-year-old Caucasian man. The nerve fibers were arranged chaotically as in a traumatic neuroma. Because of the intimate intermingling of this slow-growing tumor with the parental nerve fibers, complete excision should be avoided.

Adult↗
PubMed1993

Neuropathological findings of a patient with pyruvate dehydrogenase E1 alpha deficiency presenting as a cerebral lactic acidosis.

Neuropathological findings are reported of a 6-month-old female child with a "cerebral" lactic acidosis. A mutation in the pyruvate dehydrogenase (PDH) E1 alpha gene was found. Gross examination of the brain revealed a severe thinning of the cerebral parenchym, a marked hydrocephalus sparing the aqueduct and fourth ventricle, agenesis of the corpus callosum and heterotopic noduli of gray matter in subependymal regions. Microscopical examination showed heterotopic inferior olives, absent pyramids and focal neuroglial overgrowth into meninges. In addition some heterotopia of Purkinje cells and dysplasia of the dentate nuclei were observed. There was a marked vascular proliferation with many thin-walled, congestive vessels in the cerebral and cerebellar white matter, and to a lesser extent in the striatum. To our knowledge these cerebellar and vascular abnormalities have not been reported before in patients with "cerebral" lactic acidosis. The combination of these neuropathological findings might be characteristic for PDH deficiency and more specifically for its E1 alpha subtype. Neuropathological examination could lead to the retrospective diagnosis of PDH E1 alpha deficiency in those cases where biochemical investigations were not or incompletely performed. This may have potential implications for genetic counseling.

Acidosis, Lactic↗