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Biomedical subjects

B Sadzot

Publications and source records attributed to B Sadzot.

At least 37 records · Page 2Linked to original sources

[Neuroborreliosis].

Lyme disease, or borreliosis, is an endemic affection in Belgium. It is transmitted by a spirochete, Borrelia burgdorferi. The particularity of the infecting genomic group, Borrelia garinii, implies that half of the reported cases of Lyme disease in our country have neurologic manifestations. Due to the marked clinical heterogeneity and the difficult serologic diagnosis, neuroborreliosis is often part of the differential diagnosis in neurology. The antibiotic treatment is necessary because it decreases the risk of more advanced stages of the disease. We hope that a vaccination will soon be available in Belgium.

Anti-Bacterial Agents↗

Meningeal inflammatory pseudotumour: a case report.

We report the case of a meningeal inflammatory pseudotumour occurring in a 23-year-old male presenting with focal seizures and headaches. Brain imaging techniques showed a 3.5 cm left parietal meningeal tumour. Histology of the surgical specimen showed a dense lymphoid infiltrate permeating the dura mater and leptomeninges, consisting of a predominant polyclonal B cell population as confirmed by immunophenotyping and genotyping. Cultures of serum, CSF, and surgical specimen were negative and there was no serological evidence of a systemic dysimmune disease. The postoperative course was complicated by an episode of brain oedema resolving under steroid therapy. The patient, free from all medication, is asymptomatic at 3 years of follow-up. We discuss previously published cases and the nosology of intracranial inflammatory pseudotumours.

Adult↗

[How I treat ... refractory epilepsy by vagal nerve stimulation].

Intermittent left vagus nerve stimulation is a novel therapeutic modality that can be proposed to patients with a refractory epilepsy and for whom resective surgery is not an option. Its precise mechanism of action is not known. Controlled studies have shown that its efficacy is similar to that of antiepileptic drugs: 50% decrease in seizure frequency in 40% patients after two years. Side effects which are generally mild to moderate are the result of a diffusion of the stimulation to the larynx. No CNS side effect has been reported.

Drug Resistance↗

Familial Kufs' disease presenting as a progressive myoclonic epilepsy.

Kufs' disease is the adult form of a group of disorders referred to as neuronal ceroid-lipofuscinosis or Batten's disease. We report here the clinical and anatomopathological features of two young brothers presenting with a progressive myoclonic epilepsy corresponding to type A of the disease according to Berkovic. The first clinical manifestations occurred before 20 years of age. Diagnosis was made in the older brother at autopsy and in the younger brother from a rectal biopsy. In addition to characteristic electron microscopic findings, enlarged neurons showed strong immunoreactivity against subunit c of mitochondrial ATP synthase which has been reported previously in only a few adult cases of neuronal ceroid-lipofuscinosis. An extensive review of the published cases underlines the rarity of this condition, particularly when onset is early.

Adult↗

[Pharmacy clinics. Medication of the month. Topiramate (Topamax)].

Topiramate is a new antiepileptic drug that has now become available for prescription in Belgium. In vitro and in vivo preclinical studies have indicated that topiramate has several mechanisms of action that may contribute to its anticonvulsivant activity. A broad antiepileptic spectrum could be suspected that has been confirmed on a clinical basis. Topiramate has favorable pharmacokinetic properties: rapid absorption, long half-life and little interaction with other AED. Several meta-analysis have confirmed its efficacy, particularly as adjunctive therapy for partial onset seizures, refractory to other AED. It is actually reimbursed only for these patients but its indications will probably be widened in the future.

Anticonvulsants↗

[A neuropsychological and functional brain imaging study of visuo-imitative apraxia].

We describe the case of a 58-years-old right-handed women suffering from an occipital-parietal lesion. The administration of a cognitively based assessment tool for limb praxis (Batterie d'Evaluation des Praxies, B.E.P., Peigneux and Van der Linden, 1998) demonstrated bilateral visuo-imitative apraxia. Gesture production was mainly characterised by spatial, errors, and imitation of meaningful gestures was worse than their pantomime on verbal command. Moreover, the imitation of meaningless gestures and their reproduction on a manikin were worse than imitation of their matched meaningful gestures. In a cognitive perspective, adapted from the Rothi et al. (1997) and Goldenberg (1995) contributions to our understanding of limb praxis, this configuration of performance suggests deficits occurring at multiple levels. On one hand, it suggests either access difficulties or alteration of the output praxicon, i.e., the lexicon for visuo-kinesthetic engrams of meaningful gestures. On the other hand, the simultaneous deficit for meaningless gesture reproduction on the subject's own body and on a manikin favors an alteration of the structural descriptions of the human body (i.e., human body knowledge), underlying the mental transposition processes occurring between the visual analysis of a meaningless gestural configuration and its effective reproduction on oneself or on a manikin, thus contradicting the classic view of a direct pathway linking visual analysis and motor planning in meaningless gesture imitation. Finally, due to the output praxicon deficit, imitation of meaningful gestures is partly processed in the same way as meaningless gestures (also impaired in this case), leading to an interference effect between both degraded memory-based and visually-transposed traces, which account for imitation of meaningful gestures being worse than their pantomime on verbal command. We also assess regional cerebral metabolism using positron emission tomography (PET). Comparison with 41 healthy subjects (SPM96) demonstrated a statistically significant hypometabolism in the left intraparietal sulcus and superior parietal lobule, and in the right dorsal prestriate cortex. These results, together with a review of the other studies of visuo-imitative apraxia, suggest that the left intraparietal sulcus may be associated with access or integration of information from the output praxicon. The left superior parietal and the right dorsal prestriate deficits functionally impaired a bilateral dorsal network implied in the mental transformations of the body, thus suggesting that these mental transformations are underlined by knowledge of the human body, which may subsequently explain the deficit for the reproduction of meaningless and meaningful configurations.

Aged↗

[Initiation and discontinuation of antiepileptic treatment].

The actual decision regarding whether or not to treat a patient presenting a first seizure must be individualized, considering both the probability of a recurrence, and the perceived risks/benefits ratio of the treatment. The latter depends on the physician's assessment of the potential morbidity of another seizure versus the potential morbidity of antiepileptic drug therapy. In many situations, there is no single correct answer to the question "Should this patient be treated?". The same evaluation of the potential risks and benefit of stopping the treatment arises again when the patient has been seizure-free for a sufficient period of time. The patient must be informed of the pros and cons and should always be associated with the decision.

Algorithms↗

Tracers for imaging melanin with positron emission tomography.

The melanin binding properties of six radioligands were determined in vivo in the eyes of pigmented mice. Binding in the eyes of nonpigmented mice was used to assess nonmelanin binding characteristics. Of these radioligands, 3H-N-methylspiperone showed the best uptake and gave the best signal-to-noise ratio at all time points examined. Its binding appeared essentially irreversible. A PET study with 11C-N-methylspiperone was therefore carried out in a patient with a small ocular melanoma. Increased uptake of 11C-N-methylspiperone was observed in the melanoma. Our studies indicate that PET and radiolabeled NMSP might be used for imaging melanin and for the detection of pigmented melanoma. These results suggest that with a high resolution PET camera it may be feasible to image the melanin-containing cells (dopaminergic neurons) of the substantia nigra in the central nervous system, which could be of interest for the study of Parkinson's disease.

Animals↗

Myasthenia gravis without chronic GVHD after allogeneic bone marrow transplantation.

A 20-year-old man with aplastic anemia developed myasthenia gravis (MG) 7 months after bone marrow transplantation (BMT) from an HLA one locus-mismatched sister. Proximal muscle weakness (predominant in the lower limbs) and dysphagia occurred without any other sign of graft-versus-host disease (GVHD), 1 month after cessation of immunosuppression with cyclosporine. The diagnosis of MG was based on clinical symptoms and on neurophysiologic investigations showing a significant increase of the Jitter in single-fiber electromyography and a significant decremental response during repetitive stimulation at slow rates, but antibodies against the acetylcholine receptor (AchRab) were negative. All clinical and neurophysiological signs normalized within 1 month of treatment with low-dose prednisolone and pyridostigmine, and the patient is perfectly well 1 year after cessation of all therapy. All cases of BMT-associated MG previously published are reviewed in comparison with ours. The originality of this new observation is that this case is the only one not associated with chronic GVHD and negative for AchRab. Alternatively, MG may have been the sole manifestation of chronic GVHD in this patient.

Adult↗

Preoperative evaluation of 54 gliomas by PET with fluorine-18-fluorodeoxyglucose and/or carbon-11-methionine.

UNLABELLED: This study evaluates the usefulness of PET for the preoperative evaluation of brain gliomas and methods of quantification of PET results. METHODS: Fifty-four patients with brain gliomas were studied by PET with 18F-fluorodeoxyglucose (FDG) (n = 45) and/or 11C-methionine (MET) (n = 41) before any treatment. Results of visual analysis, calculation of glucose consumption and five tumor-to-normal brain ratios for both tracers were correlated with two histologic grading systems and with follow-up. RESULTS: Visual analysis (for FDG) and tumor-to-mean cortical uptake (T/MCU) ratio proved to be the best tools for the evaluation of PET results. Methionine was proven to be better than FDG at delineating low-grade gliomas. Tumor-to-mean cortical uptake ratios for FDG and MET were clearly correlated (r = 0.78), leading to the equation T/MCU(FDG) = 0.4 x T/MCU(MET). We showed a good correlation between FDG PET and histologic grading. MET uptake could not differentiate between low-grade and anaplastic astrocytomas but was significantly increased in glioblastomas. Low-grade oligodendrogliomas exhibited high uptake of FDG and MET, probably depending more on oligodendroglial cellular differentiation than on proliferative potential. Uptake was decreased in anaplastic oligodendrogliomas, probably due to dedifferentiation. Care must be taken with peculiar histologic subgroups, i.e., juvenile pilocytic astrocytomas and oligodendrogliomas, because of a discrepancy between high PET metabolism and low proliferative potential (good prognosis). Both tracers proved useful for the prediction of survival prognosis. Methionine proved slightly superior to FDG for predicting the histologic grade and prognosis of gliomas, despite the impossibility of differentiation between Grades II and III astrocytomas with MET. This superiority of MET could be explained by patient sampling (low number of Grade III gliomas submitted to examination with both tracers). The combination of both tracers improved the overall results compared to each tracer alone. CONCLUSION: Both tracers are useful for the prediction of the histologic grade and prognosis. The apparent superiority of MET over FDG could be due to the small number of Grade III gliomas studied with both tracers.

Brain↗

Is 11C-flumazenil PET superior to 18FDG PET and 123I-iomazenil SPECT in presurgical evaluation of temporal lobe epilepsy?

OBJECTIVE: To determine the contribution of 18FDG PET, 11C-flumazenil PET, and 123I-iomazenil SPECT to the presurgical evaluation of patients with medically intractable complex partial seizures. METHODS: Presurgical evaluation was performed in 23 patients, who were considered candidates for temporal lobe resective surgery (14 females and nine males with a median age of 34 (range 13 to 50) years). The presurgical diagnosis was based on seizure semiology as demonstrated with ictal video recording, ictal and interictal scalp EEG recordings, and MRI. RESULTS: Eighteen patients had convergent findings in clinical semiology, interictal and ictal EEG with scalp and sphenoidal electrodes, and MRI that warranted surgery without depth EEG (DEEG). In five patients with insufficient precision of localisation, DEEG with intracerebral and subdural electrodes was performed. MRI showed abnormalities in 22 out of 23 patients. Of these 22, 18 had mesial temporal sclerosis. This was limited to the mesial temporal lobe in four and more widespread in the temporal lobe in 14 patients. In one patient only enlargement of the temporal horn was found and in three others only white matter lesions were detected. 18FDG PET showed a large area of glucose hypometabolism in the epileptogenic temporal lobe, with an extension outside the temporal lobe in 10 of 23 patients. Only in one of these patients DEEG showed extratemporal abnormalities that were concordant with a significant extratemporal extension of hypometabolism in 18FDG PET. 18FDG PET was compared with the results of scalp EEG: in none of the patients was an anterior temporal ictal onset in scalp EEG related to a maximum hypometabolism in the mesial temporal area. By contrast, the region of abnormality indicated by 11C-flumazenil PET was much more restricted, also when compared with DEEG findings. Extension of abnormality outside the lobe of surgery was seen in only two patients with 11C-flumazenil and was less pronounced compared with the intratemporal abnormality. Both 18FDG PET and 11C-flumazenil PET reliably indicated the epileptogenic temporal lobe. Thus these techniques provide valuable support for the presurgical diagnosis, especially in patients with non-lesional MRI or non-lateralising or localising scalp EEG recordings. In those patients in whom phase 1 presurgical evaluation on the basis of classic methods does not allow a localisation of the epileptogenic area, PET studies may provide valuable information for the strategy of the implantation of intracranial electrodes for DEEG. Previous studies have suggested that 11C-flumazenil binding has a closer spatial relationship with the zone of ictal onset than the area of glucose hypometabolism, but this study suggests rather that the decrease in the 11C-flumazenil binding simply reflects a loss of neurons expressing the benzodiazepine-GABA receptor. 11C-flumazenil PET did not prove to be superior to 18FDG PET. CONCLUSION: In 21 patients sufficient material was obtained at surgery for a pathological examination. In 17 mesial temporal sclerosis, in one an oligodendroglioma grade B, in another a vascular malformation and in two patients no abnormalities were found. Although all 21 patients with pathological abnormality showed hypometabolic zones with 18FDG PET and a decreased uptake in 11C-flumazenil binding, there was no strong correlation between pathological diagnosis and functional abnormal areas in PET. Grading of medial temporal sclerosis according to the Wyler criteria showed no correlation with the degree of hypometabolism in either 18FDG or 11C-flumazenil PET. The interictal 123I-iomazenil SPECT technique was highly inaccurate in localising the lobe of surgery.

Adolescent↗