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Biomedical subjects

C Bergeron

Publications and source records attributed to C Bergeron.

At least 145 records · Page 8Linked to original sources
PubMed1994

Copper/zinc superoxide dismutase mRNA levels are increased in sporadic amyotrophic lateral sclerosis motorneurons.

Mutations of the Cu/Zn superoxide dismutase (SOD-1) gene were recently implicated in the pathogenesis of familial amyotrophic lateral sclerosis (ALS). We measured SOD-1 mRNA levels in motorneurons of the more common sporadic form of the disease and found a 42% increase in ALS motorneurons (P = 0.058) as compared with controls. These results suggest that oxidative stress may also play a role in the pathogenesis of sporadic ALS.

Adult↗
PubMed1994

Premature atherosclerosis with photomyoclonic epilepsy, deafness, diabetes mellitus, nephropathy, and neurodegenerative disorder in two brothers: a new syndrome?

We describe two brothers with sensorineural deafness, diabetes mellitus, progressive neurological deterioration with photomyoclonic epilepsy, and progressive deterioration in renal function, resulting in death in the third decade of life. Autopsy showed diffuse atherosclerosis and arteriolosclerosis of the systemic vasculature. There was no evidence of these abnormalities in the patients' 2 sisters or either parent. Mitochondrial enzyme analysis documented partial deficiencies of Complex III and IV of the respiratory chain. This deficiency was expressed in skin fibroblasts, kidney and liver but not in muscle. This suggests that the disease-causing mutation is either in the mitochondrial or nuclear DNA. Various modes of inheritance are considered, including maternal, autosomal recessive, or X-linked recessive. We suggest this is a new genetic syndrome characterized by an underlying metabolic disease and premature atherosclerosis, possibly of mitochondrial origin.

Adult↗
PubMed1994

Characterization of a shared epitope in cortical Lewy body fibrils and Alzheimer paired helical filaments.

The straight fibrils of the Lewy body contain an epitope related to phosphorylation of the KSPV motif common to the C termini of the 200- and 170-kDa neurofilament subunits and tau. To further characterize this phosphorylated neurofilament/tau epitope in Lewy bodies and to analyze the constituents of isolated Lewy bodies we used a combined biochemical and immunochemical approach. In formalin-fixed paraffin-embedded tissue cortical Lewy bodies were labelled by monoclonal antibodies directed to phosphorylation-dependent KSPV epitopes in the sequences of neurofilament and phosphorylation-independent epitopes. Immunoblotting of solubilized Lewy body fibrils with the same antibodies which stained Lewy bodies in tissue sections revealed that the immunoreactive Lewy body proteins were phosphorylated neurofilament subunits. An antibody to the 68-kDa neurofilament subunit labelled Lewy bodies and Lewy body protein at 50-68 kDa. We conclude that the shared phosphorylated epitope in Lewy body fibrils and paired helical filaments is related to the common KSPV sequence in neurofilament and tau, and that all three neurofilament subunits are present in the Lewy body. This result indicates that although Lewy bodies and neurofibrillary tangles share epitopes they are comprised of distinct structural subunits.

Aged↗
PubMed1994

Striatonigral degeneration: iron deposition in putamen correlates with the slit-like void signal of magnetic resonance imaging.

We report three patients with striatonigral degeneration highlighting the correlation between magnetic resonance imaging (MRI) and the pathological changes. The "slit-like void signal" observed in the putamen is typical of striatonigral degeneration and can be used to assist diagnosis during life. Our histochemical studies support the concept that increased iron deposition in the putamen is responsible for this MRI picture.

Adult↗
PubMed1994

Neurofilament light and polyadenylated mRNA levels are decreased in amyotrophic lateral sclerosis motor neurons.

The presence of large neurofilamentous accumulations in the perikaryon and proximal axon of motor neurons in amyotrophic lateral sclerosis (ALS) suggests that the expression of this abundant cytoskeletal protein may be altered. We performed quantitative in situ hybridization for the low molecular weight neurofilament subunit (NF-L) messenger RNA in six cases of sporadic ALS and six controls. We found a 41% decrease (p < 0.02) in the NF-L mRNA levels in anterior horn cells in ALS, with a 60% decrease (p < or = 0.01) in alpha motor neurons. This alteration may represent a non-specific response to axonal or neuronal injury or, alternatively, reflect the regenerative activity of residual normal motor neurons. NF-L mRNA levels were consistently low (in the third and fourth quartiles) in spheroid-bearing motor neurons, indicating that the neurofilamentous accumulations observed in ALS are not likely the result of overexpression of the NF-L gene. Total neuronal polyadenylated mRNA levels were also 50% lower (p = 0.02) in anterior horn cells and 48% lower (p < or = 0.05) in alpha motor neurons in ALS, possibly reflecting a decrease in selected mRNA species in diseased motor neurons.

Adult↗
PubMed1994

Mallory body filaments become insoluble after normal assembly into intermediate filaments.

The deposition of 8-to-10-nm filaments into inclusion bodies is a fundamental cellular change that occurs in several degenerative processes of many tissues. However, little is known about the pathological filaments including whether the filaments assemble by the same mechanisms that govern the assembly of normal intermediate filaments. We have addressed this issue by studying the in vitro reassembly of the cytokeratin filaments that are deposited into experimental murine Mallory bodies (MBs) but have not yet become covalently crosslinked components of the MB. The reassembly process of both normal hepatocellular and MB-derived cytokeratins (CKs) was similar and characterized by a hierarchy of protofilament and protofibrils with a prominent axial periodicity of approximately 21 nm (normal hepatocellular CK, 20.7 +/- 2 nm; MB-derived CK, 20.1 +/- 2 nm). Purified MB-derived CK and normal hepatocellular CK comigrated in polyacrylamide gel electrophoresis indicating composition by similar CK isoforms. These results indicate that intermediate filaments formed from MB-derived CK are indistinguishable from filaments assembled from normal CK. On this basis, we conclude that the intermediate filaments that form inclusion bodies are not aberrantly assembled but become aggregated and post-translationally modified after their initial formation.

Animals↗
PubMed1994

Vulvar vestibulitis. Lack of evidence for a human papillomavirus etiology.

Prompted by contradictory papers on the subject, we performed a prospective study to assess the possible human papillomavirus (HPV) etiology of vulvar vestibulitis. Eleven patients with periglandular vestibulitis, as well as a control group of 11 patients with condylomata acuminata, were selected. Biopsy specimens were taken for histologic and virologic evaluation. One specimen of vestibulitis showed koilocytosis. Using the polymerase chain reaction, none of the vestibulitis specimens, including the one with koilocytosis, were found to harbor HPV DNA, whereas all the condylomata acuminata contained HPV 6/11 DNA. Our results do not support an HPV etiology of vestibulitis.

Adolescent↗
PubMed1994

[Electro-conization with the diathermic loop. Indications and results].

The experiment of electro-conization with diathermic loop was effected on 185 patients. The indications are represented by: a) low grade lesions: 21 cases (11.3%) only when the squamo-columnar junction was into the endocervix; b) CIN 2: 44 cases (23.7%): c) CIN 3: 118 cases (63.7%); d) cyto-histologic discordance: 2 cases. After one year, the following results could be noted: 94.1% of the patients were cured, only 11 out of the 185 presented a recurrence (or persistence). It seemed interesting to us to study the factors which could influence the "in sano" (Free margin)/or not character of the resection. It appeared that the surface of the lesion did not seem to influence its histological result since we got: 83%, 96%, 94.5% and 92.3% of "in sano" conizations to be correlated with a lesion surface equal to 1/4, 2/4, 3/4, 4/4 of the cervical area. The second factor to be studied was the patients' age. So from 15 to 25 years (96%) of the resections were "in sano". There from 26 to 35 (92%), and from 36 to 45 (91.9%). Among post-menopausal women from 46 to 55 years old only 86.4% of electro-conizations were "in sano". Histologic alterations of the histologic specimen were noted in two cases (1%), the interpretation was easy and clear in the other cases. What about the complications? In 2 cases a moderate stenosis was to be noted; in 2 other cases: post-operative hemorragiae which were treated by a selective electro-coagulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1994

Twisted ribbon structure of paired helical filaments revealed by atomic force microscopy.

Progressive deposition of phosphorylated tau into the paired helical filaments (PHF) that compose neurofibrillary tangles, dystrophic neurites, and neuropil threads is an obligate feature of Alzheimer's disease. The standard model of PHF structure, derived from electron microscopic studies, suggests that two 8- to 10-nm filaments each composed of three to four protofilaments are wound into a helix with a maximal diameter of -20 nm and a half period of 65 to 80 nm. However, recent vertical platinum-carbon replicas of PHF more closely resemble a thin helical ribbon without constitutive protofilaments. Here we report that native PHF imaged with an atomic force microscope appear as twisted ribbons rather than the generally accepted structure derived from electron microscopic studies. These data imply that the assembly of PHF is not due to the twisting of pair-wise filaments but rather the helical winding of self-associated tau molecules arranged into a flattened structure. Future structural models of PHF should be based on quantitative data obtained from imaging techniques, such as scanning probe microscopy, which do not require harsh specimen preparation procedures.

Alzheimer Disease↗
PubMed1993

Brain S-adenosylmethionine decarboxylase activity is increased in Alzheimer's disease.

We measured the activity of S-adenosylmethionine decarboxylase (SAMDC), a key regulatory enzyme of polyamine biosynthesis, in autopsied brain from 13 patients with Alzheimer's Disease (AD). As compared with the controls, mean enzyme activity was increased by 37-96% in all seven examined brain regions with statistically significant increases in temporal cortex (+96%), frontal cortex (+69%) and hippocampus (+90%). The elevated SAMDC may have occurred as part of a generalized polyamine response to brain injury, which has been previously described in experimental animal conditions. Above-normal SAMDC activity implies increased levels/metabolism of spermidine and spermine, two polyamines which are involved in neuronal regeneration, growth factor production, and activation of excitatory N-methyl-D-aspartate preferring glutamate receptors. Our data suggest the involvement of the polyamine system in the brain reparative and/or pathogenetic mechanisms of AD.

Adenosylmethionine Decarboxylase↗
PubMed1993

Deposition of detergent-resistant neurofilaments into Lewy body fibrils.

To assess the contribution of neurofilaments (NF) to the detergent-resistant cortical Lewy body (LB) fibril we extracted LBs from Diffuse LB diseased brains and used monoclonal antibodies to probe Western transfers of solubilized LB-derived protein. Antibodies to epitopes located in the COOH-termini of the 200- and 170-kDa NF subunits (NF-H and NF-M) labelled LB proteins corresponding to full length and partially truncated or variably phosphorylated NF-H and NF-M. LB-derived protein at approximately 70-kDa did not contain epitopes detected by monoclonal antibodies to NF-L, tau or the COOH-termini of the NF-H and NF-M. We conclude that NF-H and NF-M are incorporated as integral insoluble components of the cortical LB fibril.

Antibodies, Monoclonal↗
PubMed1993

Phase II study of ifosfamide in childhood brain tumors: a report by the French Society of Pediatric Oncology (SFOP).

Forty-two evaluable pediatric patients with a variety of recurrent primary brain tumors participated in a phase II ifosfamide trial. Their mean age was 10 years. All patients were treated with ifosfamide, 3 g/m2/day for 2 days every 2 weeks. Response was assessed on clinical and radiological criteria after at least 2 courses of therapy. The overall response rate was 12% (5/42). One complete and 2 partial responses were documented in 21 patients with medulloblastoma. A partial response was demonstrated in 1 patient with primitive neurectodermal tumor (PNET) and in 1 patient with ependymoma. No activity was observed in astrocytic tumors. Toxicity was primarily neurologic (16 out of 54 patients, 30%). Hematological toxicity, without severe morbidity, was encountered in 9% of courses (16/179). Ifosfamide, administered at this dose regimen has modest efficacy in the treatment of recurrent childhood medulloblastoma and ependymoma and appears inactive for gliomas. Further trials with other dose schedules are necessary to assess the activity of this drug. However, according to the neurotoxicity observed in our trial, we would not recommend building a protocol using ifosfamide for highly progressive brain tumors.

Adolescent↗
PubMed1993

Cerebral non-Hodgkin's lymphoma discovered when treating Hodgkin's disease.

Case report of the appearance of a highly malignant cerebral non-Hodgkin's lymphoma of a diffuse large cell type, type B, occurring at the immediate onset of chemotherapy for a stage IV (mediastino-pulmonary) Hodgkin's disease (nodular sclerosis) diagnosed in a 16-year-old boy. The treatment of this cerebral lymphoma associated primary chemotherapy with high dose methotrexate, high dose aracytine, etoposide, and ifosfamide. The chemotherapy proved to be highly efficient, producing complete remission. Thoracic and abdominal irradiation for Hodgkin's disease was performed concomitantly with chemotherapy for the non-Hodgkin's lymphoma. This treatment was followed by 36 Gy of cerebral irradiation. Thirty-six months after the discovery of the cerebral non-Hodgkin's lymphoma the patient was still disease-free and doing well.

Adolescent↗
PubMed1993

Absence of protease-resistant prion protein in dementia characterized by neuronal loss and status spongiosus.

Dementia characterized by neuronal loss and status spongiosus (DNLS) is a non-Alzheimer degenerative process which is characterized by Pick-like lobar atrophy with neuronal depletion and gliosis of the cerebral cortex, corpus striatum, medial thalamus, and substantia nigra and the absence of neuronal inclusions. To further investigate the cause and pathogenesis of DNLS, we probed cerebral homogenates from three cases of DNLS for protease-resistant prion protein to determine if DNLS could be a variant of a human prion disease. Limited proteolysis of prion proteins and guanidine thiocyanate treatment of cortical homogenates was used to enrich potential abnormal prion protein immunoreactivity. Although protease-resistant prion protein was detected in a case of sporadic Creutzfeldt-Jakob disease no abnormal prion protein was found in the cases of DNLS. We conclude that DNLS is not a human prion disease and remains an important dementia of uncertain etiology.

Aged↗