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Biomedical subjects

C Bergeron

Publications and source records attributed to C Bergeron.

At least 235 records · Page 13Linked to original sources
PubMed1979

Primary empty sella: a histologic and immunocytologic study.

A primary "empty" sella turcica was found incidentally at autopsy, and the anterior lobe of the pituitary gland was studied with the immunoperoxidase technique. All five adenohypophysial cell types, ie, somatotrophs, lactotrophs, corticotrophs, thyrotrophs, and gonadotrophs (containing follicle-stimulating hormone [FSH] and luteinizing hormone [LH], were present in adequate numbers and were well granulated, indicating normal hormone storage.

Empty Sella Syndrome↗
PubMed1978

Pituitary siderosis. A histologic, immunocytologic, and ultrastructural study.

Pituitaries of 6 patients with various iron overload states have been studied by morphologic techniques, including immunostaining and electron microscopy. The immunoperoxidase technique combined with the prussian blue reaction revealed iron deposition in all five adenohypophysial cell types, indicating the iron uptake per se does not entirely block hormone storage. Iron distribution was uneven; more iron was demonstrated in PAS-positive cells than in orangeophils, and a preferential localization was disclosed in the gonadotrophs. In 2 cases of hemochromatosis, reduction of pituitary gonadotrophs was implicated in the genesis of hypogonadism. By electron microscopy, iron particles were noted in the cytoplasm of various adenohypophysiocytes, partly incorporated into lysosomes. Some adenohypophysiocytes with iron accumulation showed degranulation by light and electron microscopy and decreased hormone storage by the immunoperoxidase technique. Although these changes may be causally related to iron deposition, more work is required to prove that iron has a direct toxic effect on adenohypophysial cells.

Adult↗
PubMedDate not supplied

Nuclear compartmentalization of aluminum in Alzheimer's disease (AD).

Senile dementia of the Alzheimer type (AD) is a fatal encephalopathy of uncertain etiology. Whether the neurotoxin aluminum plays any role in the AD process in unknown. Here we report an increased amount of aluminum in a chromatin subcompartment, the micrococcal nuclease (MN; EC 3.1.31.1) accessible dinucleosome fraction, in neocortical nuclei isolated from 17 control and 21 AD-affected brains. At these MN-accessible loci we also observe an increase in H1 zero linker histone proteins, DNA-binding proteins which are thought to act as regulators of chromatin compaction. These data support the hypothesis that one deleterious effect of aluminum upon nuclear structure in AD-afflicted brain may be to condense brain chromatin nonrandomly through an interaction with H1 zero linker protein and thereby alter the ability of brain DNA to be effectively transcribed.

Adult↗
PubMedDate not supplied

Reduction of thyroid hormone receptor c-ERB A alpha mRNA levels in the hippocampus of Alzheimer as compared to Huntington brain.

A history of thyroid dysfunction has been cited as a possible risk factor for Alzheimer's disease (AD). Neurologic symptoms displayed by hypothyroid patients resemble, in part, those manifested by Alzheimer patients. To determine if a relationship exists between thyroid hormone receptor message levels and AD, in situ hybridization with tritiated antisense RNA probes for thyroid hormone receptors was used to examine the expression of these genes in Alzheimer and Huntington brain tissue. Message levels for a thyroid hormone receptor highly expressed in brain (c-ERB A alpha) was reduced by 52% in CA1 and 43% in CA2 in Alzheimer hippocampus as compared to Huntington controls. In contrast, message levels for another form of thyroid hormone receptor (c-ERB A beta 1) in Alzheimer hippocampus were not significantly different from Huntington controls. Temporal and cerebellar levels of c-ERB A alpha were elevated by 1.6-fold whereas temporal but not cerebellar levels of c-ERB A beta 1 were elevated 2.0-fold in Alzheimer brain. There was no correlation between thyroid hormone receptor levels and brain weight, autopsy interval, patient age, or the extent of neurofibrillary degeneration. Instead, decreased thyroid hormone receptor mRNA levels in Alzheimer-affected hippocampus were due to an increase in the percentage of neurons expressing lower message levels for these proteins.

Alzheimer Disease↗
PubMedDate not supplied

Normal brain development in PS1 hypomorphic mice with markedly reduced gamma-secretase cleavage of betaAPP.

Presenilin 1-null mice die at birth from brain and skeletal developmental deformities due to disrupted Notch signaling. Presenilin 1-null mice also have severely reduced gamma-secretase cleavage of betaAPP. The assumption has been that facilitation of Notch signaling and betaAPP processing by presenilin 1 are analogous functions. Here we describe a presenilin 1-targetted mouse model that expresses extremely low levels ( approximately 1% of normal) of mutant PS1-M146L. Homozygous mice have significantly reduced viability due to a Notch-like phenotype. The animals that survive have severe axial skeletal deformities and markedly diminished gamma-secretase activity and accumulation of betaAPP-C100, but no obvious abnormalities in brain development. These results suggest that, in mice, a marked reduction of PS1-facilitated gamma-secretase activity is not detrimental to normal brain development.

Amyloid Precursor Protein Secretases↗
PubMedDate not supplied

A beta peptide immunization reduces behavioural impairment and plaques in a model of Alzheimer's disease.

Much evidence indicates that abnormal processing and extracellular deposition of amyloid-beta peptide (A beta), a proteolytic derivative of the beta-amyloid precursor protein (betaAPP), is central to the pathogenesis of Alzheimer's disease (reviewed in ref. 1). In the PDAPP transgenic mouse model of Alzheimer's disease, immunization with A beta causes a marked reduction in burden of the brain amyloid. Evidence that A beta immunization also reduces cognitive dysfunction in murine models of Alzheimer's disease would support the hypothesis that abnormal A beta processing is essential to the pathogenesis of Alzheimer's disease, and would encourage the development of other strategies directed at the 'amyloid cascade'. Here we show that A beta immunization reduces both deposition of cerebral fibrillar A beta and cognitive dysfunction in the TgCRND8 murine model of Alzheimer's disease without, however, altering total levels of A beta in the brain. This implies that either a approximately 50% reduction in dense-cored A beta plaques is sufficient to affect cognition, or that vaccination may modulate the activity/abundance of a small subpopulation of especially toxic A beta species.

Alzheimer Disease↗
PubMedDate not supplied

Long-term effects of chemotherapy on dental status in children treated for nephroblastoma.

Dental abnormalities among children treated at a young age for Wilms tumor are reported. The authors retrospectively reviewed the dental records and panoramic radiographs of 27 children treated for nephroblastoma between 1994 and 1998. They evaluated the frequency of apparent microdontia, excessive caries, root stunting, hypodontia, and enamel hypoplasia and compared this group to a control group of 78 children. Seventy percent of the children developed dental abnormalities, comprising root stunting (44%), enamel hypoplasia (22%), microdontia (18%), and hypodontia (7%). Results of control subjects were significantly different regarding dental abnormalities, especially microdontia and taurodontia. These results indicate that chemotherapy in children may lead to troubles affecting teeth growing at the time of treatment. Information and prospective dental care are needed, and further investigations are required.

Antineoplastic Agents↗
PubMedDate not supplied

Quality control of cervical cytology in high-risk women. PAPNET system compared with manual rescreening.

OBJECTIVE: To compare the effectiveness of the PAPNET System with conventional rescreening of negative cervical smears in a high-risk population. STUDY DESIGN: Three thousand ninety-seven negative cervical smears from women with past history of cervical abnormalities were rescreened manually and with the PAPNET System. There were two reviews of PAPNET images: the first by two cytotechnologists with limited exposure to the instrument, and the second, limited to smears with discrepant diagnoses, by an expert in the use of the system. The remaining discrepant smears were submitted to a blinded microscopic review by a third party. The a priori consensus diagnosis was arbitrarily established when the result of two of the three reviews--manual, PAPNET and the independent third review--were concordant. The results of rescreening were compared with available biopsies. RESULTS: On manual rescreening of the 3,097 smears, 2,901 (93.66%) were reported as negative and 170 (5.49%) as abnormal. On the first PAPNET review, 2,938 (94.87%) were reported as negative and 150 (4.84%) as abnormal. There were 144 smears with discrepant diagnoses. After the second PAPNET review of these discrepant smears, the agreement between manual and PAPNET rescreening rose from 94.27% to 95.58%. A final, blinded review of 89 residual discrepant smears was used to establish consensus diagnoses. The diagnoses made by PAPNET-assisted rescreening agreed much better with the consensus diagnoses than did manual rescreening (Kappa = .61 vs. Kappa = -.32, P < .001). When compared with the results of 50 available biopsies, PAPNET-assisted rescreening also had a somewhat lower false negative rate (sensitivity 58.82% vs. 41.18%, P = .17) and a statistically significant lower false positive rate (specificity 63.64% vs. 36.36%, P = .01). CONCLUSION: PAPNET-assisted rescreening, when carried out by an experienced person, is more efficient than manual rescreening.

Cytodiagnosis↗
PubMedDate not supplied

Accuracy of thin-layer cytology in patients undergoing cervical cone biopsy.

OBJECTIVE: To compare the accuracy of thin-layer cytology with Autocyte PREP (TriPath Imaging Inc., Burlington, North Carolina, U.S.A.) with conventional smears in 500 women undergoing cervical cone biopsy. STUDY DESIGN: The study was performed among 500 consecutive women presenting for cone biopsy for high grade cervical intraepithelial neoplasia (CIN) on biopsy in 350 (70%) and discrepant cytology/colpohistology in 150 (30%). Before performing a cone biopsy, two cervical samples were collected for conventional smears and thin-layer cytologic slides, with randomization of the order. Conventional smears were stained and diagnosed at Pasteur Cerba, while thin-layer cytologic slides were processed at a local TriPath office (Meylan, France) and sent in a masked fashion for screening at Pasteur Cerba. Any slides initially read as normal were reviewed again and reported without knowledge of the other cytologic or cone biopsy data. The final cytologic diagnoses for the two methods were compared with histopathology of the cone biopsy. RESULTS: The conventional smear was unsatisfactory in 58 (11.6%) of cases, while there were 4 (0.8%) unsatisfactory thin-layer cytologic slides (P < .001). Endocervical cells were missing from 31 (6.2%) of conventional smears and 34 (6.8%) of thin-layer cytologic slides. For the pooled data, sensitivities of conventional smear and thin layer for detecting high grade CIN (0.82% and 0.86%, respectively) were similar as were specificities (0.40% and 0.43%, respectively). When first samples were compared, the sensitivities of the conventional smear and thin layer for high grade CIN were 0.79% and 0.89%, respectively (P = .02), with corresponding specificities of 0.41% and 0.36% (P < .01). CONCLUSION: When controlled for sample order, the sensitivity of thin-layer cytology for detecting high grade CIN was significantly higher than that of conventional smears in patients with previous abnormal cytology, but at the expense of specificity.

Biopsy↗
PubMedDate not supplied

Cervical smear histories of 585 women with biopsy-proven carcinoma in situ.

OBJECTIVE: To analyze the cervical cytologic smear history of women with carcinoma in situ (CIS). STUDY DESIGN: We examined cytologic smears obtained within the three-year period prior to a histologic diagnosis of CIS in 585 women for whom at least one prebiopsy smear was available. RESULTS: Among 454 patients with only one smear available for review, 9 (2%) had a negative cytologic diagnosis, 58 (13%) had low grade squamous intraepithelial lesion (LSIL), and 387 (85%) had high grade squamous intraepithelial lesion (HSIL). One hundred thirty-one women had two to five smears taken within the previous three years available for review. All the smears taken prior to biopsy showed HSIL. The original diagnosis on the other smears was negative for 78 women (60%), HSIL for 46 (35%) and LSIL for 7 (5%). ALl 132 smears originally classified as negative from 87 of 585 (14.8%) women were reviewed. Twenty-seven (20%) were then classified as showing HSIL, 10 as LSIL, 10 as atypical squamous cells of undetermined significance, 7 as unsatisfactory and 78 (59%) as remaining negative. CONCLUSION: Of smears classified as negative and taken in the three years before biopsy-proven CIS, 41% were reclassified, with half reclassified as showing HSIL.

Adult↗
PubMedDate not supplied

Case report: a preterm infant with an extradural myxopapillary ependymoma component of a teratoma and high levels of alpha-fetoprotein.

The sacrococcygeal region may be the origin of germinal tumors, of paragangliomas, and, rarely, of extradural myxopapillary ependymomas (MPE) in the newborn and child. A case is presented of a preterm child with an abdominal tumor, originating from the precoccygeal area, that turned out to be a teratoma with a component of an MPE. The high levels of alpha-fetoprotein in this preterm baby were initially misleadingly interpreted as a tumoral marker. The differential diagnosis and the difficulties in interpreting tumoral markers in infants are discussed.

Female↗
PubMedDate not supplied

[Orbital and muscular relapse of Burkitt's lymphoma].

We report the case of a child presenting with abdominal Burkitt's lymphoma in whom a relapse presented as orbital and muscle involvement. This clinical feature is extremely rare. Two muscle and one orbital biopsies were necessary to obtain proper diagnosis. A new extension check-up showed bone marrow invasion and normal cerebrospinal fluid. This relapse was successfully treated by conventional chemotherapy and consolidated with high-dose chemotherapy, total body irradiation and autologous bone marrow transplantation. Eighteen months after transplantation, the child may be considered as definitively cured.

Bone Marrow Transplantation↗
PubMedDate not supplied

Clinical importance of erythrocyte polyamine level determination during bone marrow transplantation in children.

Previous studies have shown that red blood cell (RBC) spermidine (Spd) and spermine (Spm) concentrations appear to be a reliable index of cell proliferation. Our aim was to study the RBC polyamine level evolution (Spd and Spm) in bone marrow (BM) transplanted children. Because of our interest in the finding of an early blood criteria of BM regeneration, our study was based upon the chemotherapy - induced post-transplant aplasia period. After BM transplantation, two main periods were observed: the first (A-period) corresponded to abnormally low Spd levels. This period ended with an increasing amount of Spd reaching normal values and with an inversion in the Spd/Spm ratio which became greater than 1. The second (B) period was usually linked to abnormally high RBC Spd concentrations and a Spd/Spm ratio greater than 1. The end of the B-period was characterized by an increase in the granulocyte count (reaching 0.5 X 10(9) cells/l). Since the A- and B-periods are considered as a post-transplant aplasia period (only according to leukocyte count) and since normal RBC Spd levels occurred 14 days (SD = 4) after BM transplantation and 16 days (SD = 12) before granulocyte rise, these data led us to consider erythrocyte polyamine levels to be an earlier biological criteria of bone marrow engraftment than the number of circulating granulocytes.

Adolescent↗