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Biomedical subjects

C Bergeron

Publications and source records attributed to C Bergeron.

At least 217 records · Page 12Linked to original sources
PubMed1987

Amino acids, glutathione, and glutathione transferase activity in the brains of patients with Alzheimer's disease.

We measured the contents of amino acids and related amino compounds in autopsied brain from 22 patients with Alzheimer's disease (AD) and in cortical biopsy specimens from 2 other patients. The diagnosis of AD was established neuropathologically in all 24 patients by the presence of both neurofibrillary tangles and neuritic plaques in neocortex. The mean contents of gamma-aminobutyric acid (GABA), and of the GABA dipeptide homocarnosine, were significantly reduced in frontal and occipital cortices and in hippocampus of the autopsied brains of AD patients compared to control patients without neurological disease. However, GABA contents were normal in frontal cortex in biopsy samples from 2 patients. Phosphoethanolamine contents were significantly reduced at autopsy in frontal and occipital cortex, and in the substantia innominata. We found no evidence of a deficiency of glutamate, aspartate, or taurine in AD brain, as has been claimed. Glutathione contents and glutathione transferase activities were normal in frontal cortex and substantia innominata. The mechanism of neuronal death in patients with AD is unlikely to involve either insufficient synthesis of glutathione or failure to conjugate free radicals with glutathione.

Adolescent↗
PubMed1987

Human brain dopamine receptors in children and aging adults.

Since spontaneous oral dyskinesias are more prevalent in the elderly, and since these movements may be controlled by the balance of brain dopamine D1 and D2 dopamine receptors, we measured the densities of these receptors in 247 postmortem brain striata. In childhood, the densities of D1 and D2 dopamine receptors in the brain striatum rise and fall together. After age 20 years, D1 receptors disappear at 3.2% per decade while D2 receptors disappear at about 2.2% per decade. Overall, therefore, the D1/D2 ratio falls with age. Since perioral motion in rats is dominated by a high D1/D2 ratio, the observed decline in the human D1/D2 ratio with age suggests that the perioral control mechanisms for humans and rats may be different.

Aged↗
PubMed1987

Alpha-tocopherol and beta-carotene do not protect marmosets against the dopaminergic neurotoxicity of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.

Idiopathic Parkinson's disease (PD) may possibly be caused by one or more unidentified neurotoxins present in the environment, or formed endogenously, which progressively damage dopaminergic nigrostriatal neurons. N-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is an experimental neurotoxin which produces biochemical and neuropathological changes in humans, lower primates and mice that closely resemble those found in PD. Because the mechanisms of neuronal damage in both idiopathic PD and in the MPTP model of PD may involve free radical formation in the substantia nigra, antioxidants might protect dopaminergic neurons. Previously, we found that both alpha-tocopherol and beta-carotene partially protected mice against MPTP. However, in the experiments described in this paper, neither alpha-tocopherol nor beta-carotene, each administered in massive doses, had any demonstrable protective effect for dopaminergic nigrostriatal neurons in marmosets injected with low doses of MPTP. Without more knowledge about the identity of the neurotoxin(s) causing idiopathic PD, and their mechanism of action, it is not possible at this time to predict whether these 2 antioxidants might be clinically useful in preventing or ameliorating PD.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1987

Human brain D1 and D2 dopamine receptors in schizophrenia, Alzheimer's, Parkinson's, and Huntington's diseases.

Because dopamine D2 receptors are known to be elevated in schizophrenic brain striata, this study examined whether a similar dopamine receptor elevation occurred in other diseases including neuroleptic-treated Alzheimer's and Huntington's diseases. The average D1 density in postmortem striata from Alzheimer's patients was 17.6 +/- 0.1 pmol/g, similar to an age-matched control density of 16.6 +/- 0.4 pmol/g. The average D1 density in schizophrenia patients was 19.0 +/- 0.6 pmol/g, similar to the age-matched control density of 17.9 +/- 0.6 pmol/g. In Parkinson's disease patients, however, the D1 receptor density was elevated, with values of 22.8 +/- 1.2 pmol/g (in patients not receiving L-DOPA) and 19.6 +/- 1.5 pmol/g (in patients receiving L-DOPA) compared to the age-matched control density of 16.0 +/- 0.4 pmol/g. The D2 receptors in Alzheimer's striata averaged 13.4 +/- 0.6 pmol/g (in patients who had not received neuroleptics), almost identical to the control density of 12.7 +/- 0.3 pmol/g. The average D2 density in neuroleptic-treated Alzheimer's striata was 16.7 +/- 0.7 pmol/g, an elevation of 31%, the individual values of which had a normal distribution. In Parkinson's disease patients, the D2 densities were elevated in tissues from patients not receiving L-DOPA (19.9 +/- 1.5 pmol/g in putamen and 14.8 +/- 1.2 pmol/g in striatum) compared to the age-matched control values of 13.0 +/- 0.4 pmol/g and 12.6 +/- 0.3 pmol/g, respectively. In Huntington's disease patients, the D2 density averaged 7.5 +/- 0.4 pmol/g in patients who had not received neuroleptics, but was 10.3 +/- 0.6 pmol/g in those who had. Although all of the D1 and D2 densities in each of the above diseases and subgroups revealed a normal distribution pattern, the D2 densities in schizophrenia displayed a bimodal distribution pattern, with 48 striata having a mode at 14 pmol/g, and the other 44 striata having a mode at 26 pmol/g. Thus, compared to the neuroleptic-induced and unimodal elevations in D2 of 31% in Alzheimer's disease and 37% in Huntington's disease, the schizophrenic striata with a mode of 26 pmol/g (105% above control) appear to contain more D2 receptors than can be accounted for by the neuroleptic administration alone.

Adult↗
PubMed1987

Calmodulin and calbindin D28K in Alzheimer disease.

The calcium binding proteins, calmodulin and calbindin D28K, were measured by radioimmunoassay in cerebral cortex from brains with degenerative brain diseases associated with dementia. Samples were obtained from 17 normal control brains, 18 Alzheimer affected brains, and 15 brains of patients who died of a dementia process other than Alzheimer disease. Calmodulin content in the non-Alzheimer group was not significantly different from control. However, in the Alzheimer group, frontal, temporal, parietal cortex, and subjacent white matter calmodulin content was significantly reduced (66% of that found in the other 2 groups). Calmodulin extracted from temporal cortex also demonstrated reduced efficacy as an activator of 3',5' cyclic nucleotide phosphodiesterase. Calbindin D28K was reduced both in Alzheimer and non-Alzheimer dementia brains. Reduced concentrations of these important proteins may affect calcium homeostasis and the regulation of a large number of calcium mediated brain functions.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1987

Human papillomavirus type 16 in intraepithelial neoplasia (bowenoid papulosis) and coexistent invasive carcinoma of the vulva.

Tissues from two cases of bowenoid papulosis of the vulva with coexistent invasive squamous cell carcinoma were evaluated for the presence of human papillomaviruses (HPVs) and for nuclear DNA content. In both cases, HPV type 16 and nuclear aneuploidy were found in bowenoid papulosis as well as in invasive carcinoma. Patterns of hybridization suggested that the viral genome was integrated into the cellular genome in both bowenoid papulosis tissues as well as in invasive carcinoma tissues. These observations suggest that lesions designated as bowenoid papulosis may have invasive cancer potential. The term vulvar intraepithelial neoplasia seems to be more appropriate for HPV-16-containing aneuploid, intraepithelial lesions of the vulva.

Adult↗
PubMed1987

Multicentric human papillomavirus infections of the female genital tract: correlation of viral types with abnormal mitotic figures, colposcopic presentation, and location.

Human papillomavirus deoxyribonucleic acid (DNA) was identified by Southern blot hybridization in 21 of 24 patients with multicentric anogenital lesions and in 46 of 61 individual lesions. Type 6/11 was present in nine patients, type 16 in one, an undetermined type in one, and more than one type in ten patients. Mixed types were present in eight of 46 virus-positive individual lesions. Abnormal mitotic figures were found in 16, 87, and 75% of lesions associated with type 6/11, type 16, and mixed types, respectively. Colposcopic presentation or location of lesions was not predictive of viral types. The relatively high rate of mixed human papillomavirus types in multicentric lesions and in single lesions, and the lack of absolute correlation between viral types and abnormal mitotic figures, suggest that lesions should be removed to prevent viral transmission and possible progression to carcinoma.

Biopsy↗
PubMed1987

[Tumors of the liver secondary to androgen therapy. Apropos of 2 cases in children].

The authors report 2 cases of hepatocellular tumour in children treated with anabolic androgens for aplastic anemia. In both cases, the presentation was by a picture of acute abdomen due to hemoperitoneum caused by tumour rupture. In the first case, there was multiple hepatic adenomas necessitating right hepatic lobectomy. The second infant had a single tumour of segment IV treated by simple excision of the tumour. It was a hepatocellular-carcinoma. Follow-up for one year after the initial operation showed no signs of recurrence in both infants. The review of the literature permitted us to find 48 other cases of hepatocellular tumour secondary to androgen therapy. In order of frequency, the hepatocellular-carcinoma is the most frequent and it is usually single; followed by the adenoma which is usually multiple. The other types of tumours are rare: focal nodular hyperplasia, angiosarcoma and cholangiocarcinoma. The hepatocellular-carcinoma and adenoma have some characteristic features: spontaneous regression may occur after withdrawing of androgens; the risk of rupture is important; their evolution is almost always favorable despite of a severe histopathological picture; the alpha-foeto-protein is nearly always negative; and the metastasis are exceptional. The hepatocellular-carcinomas associated with androgen therapy are probably just adenomas with marked dysplasia, but their long term malignant potential remain unknown. Except in case of rupture, surgical intervention should be postponed until the effect of discontinuing the hormonal therapy is assessed, because of the potential for spontaneous regression. The administration of antineoplastic chemotherapeutic agents should be reserved for the tumours showing evidence of malignancy.

Adenoma↗
PubMed1987

[Primary lymphoma of the penis].

The authors report a case of lymphoma of the penis in a 54 year old man with a follow-up of four years without recurrence. A review of the few examples found in the literature suggests that this is the first well-documented case of primary lymphoma of the penis.

Humans↗
PubMed1987

Amyloid angiopathy in Alzheimer's disease.

Thirty cases of Alzheimer's disease and 30 age-matched controls were studied to determine the incidence of cerebral amyloid angiopathy and its relationship to age, neuritic plaque formation, and amyloid plaque content. Cerebral amyloid angiopathy (CAA) was present in 86% of AD cases and 40% of age-matched controls. Its frequent occurrence in AD is not merely a reflection of the advancing age of this group: it was seen only in the presence of neuritic plaques, regardless of age, and represents an integral component of AD. Neuritic plaques however, did occur in the absence of CAA in 17% of all cases. The amount of vascular and plaque amyloid tended to be of comparable severity in many cases, but significant discrepancies were observed, with preferential deposition of amyloid in either plaque or vessel. Our results suggest that neuritic plaque formation and amyloid deposition are linked genetically or etiologically, but independently expressed, without a cause-and-effect relationship.

Adult↗
PubMed1985

Atypical presentation of progressive supranuclear palsy.

Four pathologically documented cases of progressive supranuclear palsy are reported. Two patients exhibited severe dementia and 2 parkinsonism; none had the classic ophthalmoplegia. On retrospective analysis, clues to the diagnosis included early prominent gait disturbance, apraxia of eyelid opening in 1 patient, lack of tremor, poor response to levodopa-carbidopa, and severe rigidity with a posture of neck extension terminally in 1 patient. The clinical presentation of progressive supranuclear palsy, therefore, is not as stereotyped as previously thought, and the diagnosis can be overlooked if one adheres rigidly to the classic diagnostic criteria.

Aged↗
PubMed1985

Dolichols are elevated in brain tissue from Alzheimer's disease, but not in urinary sediment from Alzheimer's disease and Down's syndrome.

Long-chain polyisoprenoid alcohols (dolichols) were measured in different brain regions dissected postmortem from 26 histopathologically confirmed cases of Alzheimer's disease and 24 age-matched nonAlzheimer control patients. They were significantly elevated in all parts of the cerebrum, but not in the cerebellum, of Alzheimer patients. The highest values were found in the temporal cortex and hippocampus. Out of the individual dolichol molecular species, the one with the most isoprene units (C105) was significantly increased in the temporal cortex, hippocampus, and basal forebrain of Alzheimer patients, compared with the controls. Dolichols were normal in the urinary sediment of 10 Alzheimer patients and nine patients with Down's syndrome, in comparison to age-matched controls for both groups. This is in contrast to neuronal ceroid-lipofuscinosis patients in whom dolichols are elevated in cerebral cortex, as well as in the cells of the urinary sediment, indicating generalized ceroid-lipofuscin storage.

Aged↗
PubMed1984

Bimodal distribution of dopamine receptor densities in brains of schizophrenics.

The dopamine hypothesis of schizophrenia was examined by measuring the density of dopamine receptors in the postmortem brains of 81 control subjects and 59 schizophrenics from four different countries. The densities of dopamine receptors in the tissues from the schizophrenic patients had a bimodal distribution in the caudate nucleus, putamen, and nucleus accumbens. One mode occurred 25 percent above the control density, and a second mode occurred at a density 2.3 times that of the control density for all three regions. Although almost all the patients had been medicated with neuroleptics, the two modes had the same dissociation constant for the labeled ligand used, suggesting that the neuroleptic doses were similar for the two populations of schizophrenics. The results thus provide direct evidence for two distinct categories of schizophrenia.

Antipsychotic Agents↗
PubMed1984

Chromatin structure in dementia.

Nuclei extracted from neocortex of patients with Alzheimer's disease and treated with micrococcal nuclease release a population of dinucleosomes that contain an increase in the linker histones H1o and H1oo . Five other degenerative brain diseases that clinically resemble Alzheimer's disease do not result in these changes, although Pick's disease is associated with an increase in H1 on dinucleosomes. Histones from nuclei of patients with Alzheimer's disease are also more resistant to salt-induced release from chromatin than are those from age-matched control subjects. These results support the hypothesis that an alteration in chromatin structure is a marker for Alzheimer's disease.

Aged↗