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Biomedical subjects

A Lavergne

Publications and source records attributed to A Lavergne.

At least 37 records · Page 2Linked to original sources
PubMed1994

TH mRNA over-expression in rats with chronic excitotoxic striatal lesions.

Twenty weeks after ibotenic acid lesions of the striatum, the amount of tyrosine hydroxylase (TH) in this structure was markedly increased. This was accompanied by a 3-fold increase in TH mRNA levels in the ipsilateral subtantia nigra (SN). Striatal levels of dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) were markedly reduced. In the nucleus accumbens, spared by the lesion, DA neurotransmission was also altered, as evidenced by a reduction of DA and DOPAC, but no increase in TH could be detected. TH mRNA levels were moderately enhanced in the ventral tegmental area (VTA). Thus, lesioning in the striatum induces TH gene activation in both SN and VTA neurones, not strictly related to DA function at the terminal level.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Regulation of tyrosine hydroxylase gene expression in mesencephalic dopamine neurons: effect of imipramine treatment.

The effects of a chronic imipramine treatment on the mesoamygdaloid pathway of rats were examined. Using semiquantitative immunocytochemical techniques, it was observed that the level of TH mRNA was decreased in the ventral tegmental area (VTA). In contrast, the TH protein was increased in both the VTA and amygdala. The TH activity was decreased in the amygdala when assessed under normal conditions but increased after a preincubation to phosphorylate the enzyme, suggesting a lowering of the protein-specific activity in the terminals. These results show that TH protein turnover in the mesoamygdaloid neurons can be reduced by chronic imipramine treatments, thereby producing an accumulation of inactive TH protein in the neurons while also decreasing TH gene activity in the cell bodies.

Amygdala↗
PubMed1994

Multiple lymphomatous polyposis of the gastrointestinal tract. An extensive histopathologic and immunohistochemical study of 12 cases.

BACKGROUND: Multiple lymphomatous polyposis (LP) is a rare entity, characterized by multiple polypoid tumors involving several segments of the gastrointestinal tract. METHODS: In this large retrospective series of 12 patients with LP, histologic and immunohistochemical features were investigated from patients with multiple biopsy samples from each site (500 gastrointestinal biopsies). Immunohistochemistry was performed on paraffin embedded biopsies from 12 patients and on frozen tissue biopsies from 8 patients, for each of whom at least two different anatomic sites were studied. RESULTS: Histologic features always were characterized by nodules located in mucosa and submucosa composed of lymphomatous, small cleaved cells. B-cell phenotype of the neoplastic cells was the same phenotype as adult mantle-zone cells or fetal follicle cells (frequent coexpression of surface IgM and surface IgD, and weak expression of CD5, CD35+, CDw32+, and CD23-). Tested cases expressed bcl-2. Five to 20% of LP cells were positive for the monoclonal antibody Ki-67. Five patients died within 5-32 months after diagnosis. Frequent extradigestive sites were also identified. There were two unique findings: five cases with digestive tract lymphoepithelial lesions (LEL), and one secondary transformation to large B-cell malignant lymphoma. CONCLUSIONS: To the authors' knowledge, this is the largest series so far of LP studied with immunohistochemistry on frozen sections. Mantle-cell B cell phenotype of the nodular monotonous, small cleaved cells is confirmed. This entity may be classified as mantle-cell lymphoma with a similar aggressive clinical course, and treated as a high grade B-cell lymphoma. The authors know of no such LEL that has been reported previously, and secondary transformation has been described only briefly in one case.

Adult↗
PubMed1994

Extensive small intestinal T-cell lymphoma of low-grade malignancy associated with a new chromosomal translocation.

BACKGROUND: Primary T-cell lymphoma of the small intestine is rare, and most cases have proved rapidly fatal. METHODS: We describe a case of lymphoma involving the small intestine uniformly and extensively in a 28-year-old man on initial examination seen with long-standing diarrhea, malabsorption, and recurrent episodes of intestinal obstruction. Clinical remission was obtained with pentostatin (2'-deoxycoformycin, supplied by Professor Catovsky, London UK) after the patient had failed to improve under conventional chemotherapy. Tumor specimens as well as mesenteric lymph node, liver, and bone marrow specimens were studied with conventional pathology and immunochemistry. Additionally, mesenteric lymph nodes and peripheral blood cells were studied for T-cell receptor (TCR) gene rearrangement and karyotype. RESULTS: Lymphoma cells were small T-lymphocytes with irregular pleomorphic nuclei, bearing the CD3, CD4 and TCR alpha-beta phenotype. Peripheral-blood cytology and bone marrow biopsy were normal. Southern blot analysis of the TCR beta-chain gene revealed the same monoclonal rearrangement in the mesenteric lymph nodes and peripheral blood lymphocytes. An as yet undescribed t(4;16)(q26;p13) translocation, involving the region where the interleukin-2 (IL-2) gene has been mapped, was present in the mesenteric lymph nodes and peripheral blood lymphocytes. CONCLUSION: We believe this is the first description of an extensive, small intestinal lymphoma of low-grade malignancy made up of monoclonal T-cells with a TCR alpha-beta and helper/inducer phenotype, associated with a novel chromosomal translocation.

Adult↗
PubMed1994

Colonoscopy of acute colitis. A safe and reliable tool for assessment of severity.

Complications that might lead to surgery in severe attacks of ulcerative colitis have been found to be correlated with the depth of colonic ulcerations as measured by pathological examination of colectomy specimens. In order to evaluate the value of colonoscopy for the assessment of colonic ulcerations, we have reviewed the clinical, biological, colonoscopic, and anatomical findings in 85 consecutive patients with attacks of ulcerative colitis involving at least the rectosigmoid and part of the descending colon, seen in our center between 1981 and 1989. All had colonoscopy performed by a senior endoscopist at entry. Extensive deep colonic ulcerations were diagnosed in 46 of them, and moderate endoscopic colitis in 39. No complication related to colonoscopy occurred except for one colonic dilatation. Forty-three of the 46 patients with severe endoscopic colitis were operated upon; 38 of them failed to improve with high-dose corticosteroids and five had a toxic megacolon. Extensive ulcerations reaching at least the circular muscle layer were found at pathological examination of colectomy specimen in 42 of the 43 patients. Conversely, 30 of 39 patients with moderate endoscopic colitis went into clinical remission with medical treatment, and only nine patients needed further surgery because of medical treatment failure. Six of these nine patients underwent another colonoscopy prior to colectomy, and all six showed features of severe endoscopic colitis. Deep ulcerations reaching the circular muscle layer were found at pathological examination in five of these six patients and in one additional patient whose colonoscopy had been performed 21 days before colectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1994

[Seven cases of subependymoma. Anatomoclinical study and review of the literature].

Subependymomas are uncommon, benign, slowly growing lesions usually located in the fourth ventricle. Their morphology is characteristic, but their histogenesis remains controversial. Seven cases observed in our laboratory over a period of 7 years are reported. Most tumors were located axially in the brain stem, and symptoms were more variable than usually reported. The histological appearance was fairly uniform. Immunohistochemistry showed that the fibrillary component was composed of glial fibers. Ependymary differentiation is inconstant on electron microscopy. The pathogenesis of the lesion (tumor, hamartoma or reactive proliferation) is debated in the literature as is the histogenesis.

Adult↗
PubMed1993

Nucleolar organizer regions (NORs) staining and proliferating cell nuclear antigen (PCNA) immunostaining in mucosa-associated lymphoid tissue (MALT) gastric lymphomas.

Nucleolar organizer region-associated proteins (AgNOR) and proliferating cell nuclear antigen (PCNA) have been studied by means of a silver staining technique and immunohistochemistry, in paraffin-embedded, gastrectomy specimens of 12 low-grade and 13 high-grade gastric MALT lymphomas respectively. A significant difference was found between the AgNOR count and PCNA index of low-grade lymphomas (mean AgNOR count 2.5 and mean PCNA index 8.33%) and high-grade lymphomas (mean AgNOR count 8.67 and mean PCNA index 49.7%). It is suggested that both methods are useful adjuncts to histopathology for the distinction between low and high grade gastric MALT lymphomas. We also found heterogeneity in AgNOR counts and PCNA index among individual cases of either low or high grade MALT gastric lymphomas. This suggests that the AgNOR count and PCNA index is helpful in the individual approach of the proliferation rate of each tumour, a parameter of potential importance for predicting the biological behaviour of the tumour and the prognosis of the disease.

Antigens, Neoplasm↗
PubMed1992

Peritoneal sarcoidosis. An unrecognized cause of sclerosing peritonitis.

In a Caucasian woman with a history of ocular and pulmonary sarcoidosis, the occurrence of sclerosing peritonitis with exudative ascites but without any of the well-known causes of this syndrome prompts us to consider that sclerosing peritonitis is a manifestation of sarcoidosis. The dramatic improvement that occurred on corticosteroid therapy adds credibility to this previously unreported association.

Chronic Disease↗
PubMed1992

[Digestive lymphomatous polyposis].

We report 7 prospectively followed cases of lymphomatous polyposis of the gastrointestinal tract. They were characterized by multiple polypoid lesions affecting several segments of the gastrointestinal tract always involving the colon and the rectum. An ileocecal mass was present in 4 cases. Regional lymph node involvement was constant. Peripheral lymphadenopathy was frequent (5 cases out of 7), as was other extra-digestive extension to the bone marrow (4 cases out of 7) and cavum (3 cases out of 7). The histopathological aspect was that of a small cleaved cells (working formulation) or centrocytic (Kiel classification) non-Hodgkin's lymphoma. The peculiar morphology and phenotype of the tumoral B-lymphocytes suggest their possible follicle marginal zone origin. Lymphomatous polyposis bore a rapidly fatal prognosis in every case (mean survival 20 months). This study of seven patients together with the 20 well-documented cases of the literature confirms the existence of lymphomatous polyposis as a distinctive clinicopathological entity among gastrointestinal non-Hodgkin's lymphoma.

Adult↗
PubMed1992

Primary B-cell gastric lymphomas of mucosa-associated lymphoid tissue. Histological and immunohistochemical study of ten cases on surgical specimens.

Ten cases of gastric mucosa-associated lymphoid-tissue B-cell lymphoma were studied on surgical specimens by histology and immunohistochemistry, with monoclonal and polyclonal antibodies for B- and T-cells. For the first time, percentage of centroblast-like cells was appreciated, using their LN1 positivity, by opposition to the negativity of centrocyte-like cells (LN2 immunoreactivity alone). Lymphomas were divided into four main groups: A) centrocyte-like cells; B) centrocyte-like cells and immunocytoma; C) centrocyte-like cells admixed to centroblast-like cells; and D) centrocyte-like cells, immunocytoma and at least 30% of centroblast-like cells. Group C was divided into 3 subgroups: C1 (rare centroblast-like cells); C2 (30-50% of centroblast-like cells); and C3 (predominant centroblast-like cells). Therefore low grade (A, B, C1) and high grade malignancy groups (C2, C3, D) were identified: this preliminary subdivision could be extended in larger series and applied to mucosa-associated lymphoid-tissue lymphoma from other sites. Furthermore, the possible prognostic significance of this subdivision could be evaluated by correlation with long term follow-up.

Antigens, CD↗
PubMed1990

[Celiac disease and collagenous colitis. A fortuitous association].

We report the cases of two patients with coeliac disease in whom chronic diarrhoea persisted in spite of strict adherence to a gluten free-diet and regression of intestinal villous atrophy. Collagenous colitis was evidenced in both patients. Six cases of such association have already been described. Because of subepithelial deposition of collagen in the colon of collagenous colitis and in the small intestine of coeliac disease, it has been suggested that the colonic collagen band might reflect a toxic effect of gluten on colonic epithelium. However, thickening of the colonic collagen band during strict gluten free-diet, as observed in one of our cases, is not in favour of this hypothesis.

Adult↗
PubMed1989

Peculiar acute toxic colitis after ingestion of colocynth: a clinicopathological study of three cases.

We report three examples of toxic acute colitis which occurred after ingestion of colocynth (Citrullus colocynthis) for ritual purposes. The prominent clinical feature was dysenteric diarrhoea; colonoscopic changes included congestion and hyperaemia of the mucosa with abundant exudates but no ulceration or pseudopolyp formation. A causal relationship between colonic injury and the intake of colocynth was supported by the following features: (1) the pharmacology of the colocynth extract ingested; (2) the temporal relationship between colocynth intake and clinical onset (eight to 12 h); (3) the rapid recovery within three to six days, with normal endoscopy at day 14; (4) the absence of other possible causes for the observed patterns, except in one case, in which a concomitant intestinal infection with Clostridium perfringens Type A was discovered; (5) the specific pathological features. Colonic biopsies taken 27, 44, and 72 h after colocynth intake showed: erosions with fibrino-purulent exudate, early fibrosis of the lamina propria, hyaline thickening of the superficial epithelial basal membrane. These pathological features completely disappeared within 14 days in all three cases.

Acute Disease↗
PubMed1989

Peripheral T-cell lymphoma or Hodgkin's disease in a HIV seropositive patient: a histopathological study.

Malignant lymphomas occurring in patients with AIDS are usually derived from the B-cell lineage while T-cell malignant lymphomas are very rare in these patients. We report a HIV seropositive 29-year-old homosexual man in whom cervical lymph node biopsy showed an atypical lymphoproliferative process. On morphological and paraffin section immunohistochemical grounds the possibility of Hodgkin's disease (HD) mixed cellularity was initially suggested, but frozen section immunohistochemical studies revealed that the cellular infiltrate exhibited an aberrant pan T immunophenotype and consequently the diagnosis of peripheral T-malignant lymphomas (T-ML) was made. However, genotypic studies would be required to definitely confirm this diagnosis, in such cases. In our case, varying numbers of small and medium-sized cells were positive for both Leu 3/CD4 and Leu 2/CD8 whereas some large cells reacted only with Leu 3/CD4 antibody. Some medium-sized, large and giant cells showed cytoplasmic positivity for Leu M1/CD15. Furthermore, the positivity of many large and giant cells with the activation markers BerH2/CD30, Ki-1/CD30, Tac/CD25 and HLA-DR suggested an activation state for these cells. Our findings emphasize the usefulness of frozen section immunohistochemical methods in order to investigate the spectrum of lymphoid malignancies occurring in HIV seropositive patients, and confirm results of previous studies which stressed the diagnostic difficulties that may appear in distinguishing HD from peripheral T-ML.

Adult↗