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Biomedical subjects

B Pasquier

Publications and source records attributed to B Pasquier.

At least 73 records · Page 4Linked to original sources
PubMed1994

Stereo-EEG of interictal and ictal electrical activity of a histologically proved heterotopic gray matter associated with partial epilepsy.

Magnetic resonance imaging allows the identification of heterotopic gray matter (HGM) in medically intractable partial epilepsies. The relationships between HGM and the epileptogenic zone remain, however, unclear. In a case of a temporo-parietal epilepsy studied by stereo-EEG, interictal and ictal electrical activity of a temporal HGM were recorded, showing: (1) an intralesional electrical activity, (2) the possible presence of asynchronous spikes, and (3) an early but never initial, or isolated, involvement during ictal discharges. This suggests that the presurgical and surgical management of HGM must be guided, as for other lesions, by the coherence existing between ictal clinical and electrical features, and anatomical data.

Adult↗
PubMed1994

Intracranial plasma cell granuloma: a report of four cases.

Inflammatory pseudotumors (IPT) are rare lesions composed of inflammatory cells admixed with collagen tissue. Although IPT are ubiquitous, intracranial locations are rare. In this study, four intracranial IPT of the plasma-cell-granuloma (PCG) type are reported. Four patients presented with lesions located, respectively, in the right cavernous sinus, the left cavernous sinus with extension to the tentorium cerebelli, the vermis cerebelli, and the pituitary stalk. All patients were operated on, but complete resection could not be achieved in cases 1 and 2. Follow-up was favorable in all cases, although case 1 still complained of headaches 2 years after operation. All cases were studied on histologic and immunohistochemical bases, and ultrastructural analysis was performed on two cases. In cases 1, 2, and 4, IPT were made up of plasma cells admixed with lymphocytes and rare histiocytes in a fibrous tissue-the density of which varied from case to case. In case 3, the mass was composed of plasma cells associated with numerous foamy histiocytes and polymorphonuclear cells. No light chain restriction could be demonstrated when immunohistochemistry was performed, and ultrastructural study did not disclose features reminiscent of meningioma or histiocytosis X. Intracranial IPT should not be confused with other diseases such as meningioma, lymphoproliferative disorders, or histiocytosis X. Although intracranial locations are much rarer than pulmonary ones, histology is identical in both sites and shows different patterns in its evolution. This is in agreement with the inflammatory origin of this lesion.

Adult↗
PubMed1994

Carcinoid tumour complicating inflammatory bowel disease. A study of two cases with review of the literature.

Two cases of carcinoid tumour complicating inflammatory bowel disease (IBD) are presented. Both tumours were located in the appendiceal tip. The first case occurred in a man with Crohn's disease (CD), and the second one in a woman suffering from ulcerative colitis (UC). Histochemical and immunohistochemical studies were not allowed on case 1 because the tumour was not still present on serial sections of the appendix. On case 2, tumour cells were not reactive with Grimelius and Masson-Fontana stainings, but were strongly stained with anti-keratin and anti-chromogranin monoclonal antibodies (MAb), and faintly expressed neuron specific enolase (NSE), and Leu-7. Both cases occurred in inflammatory or damaged mucosa which exhibited Paneth cell metaplasia and hyperplasia and areas indefinite for dysplasia. Along with these lesions, hyperplasia of enteroendocrine cells was pointed out in the neighbouring appendiceal and colonic mucosa by means of anti-chromogranin MAb. These data suggest that the association of carcinoid tumour with IBD, albeit rare, is not coincidental and is the result of hyperplastic and dysplastic troubles that may involve enteroendocrine cells as well as such other derivatives of digestive stem cells as columnar cells, goblet cells and Paneth cells.

Adult↗
PubMed1994

[Bacillary angiomatosis related to Rochalimaea quintana. Anatomoclinical and ultrastructural study of cutaneous localizations in AIDS].

We report a case of bacillary angiomatosis in a 53-year-old homosexual man with acquired immunodeficiency syndrome (AIDS). Pathological and bacteriological studies of cutaneous nodules led to the identification of a rickettsia: Rochalimaea quintana. This observation prompted us to relate the clinical presentation of cutaneous and visceral forms of this disease. Histopathological patterns are also considered. They usually consist in a lobular proliferation of capillaries with plump and sometimes epithelioid endothelial cells. Polymorphonuclear cells, histiocytes and necrotic areas may be present. The most characteristic feature is the presence of interstitial, granular and amorphous clusters of bacteria. Diagnostic problems can be raised with Kaposi's angiosarcoma which can be associated with bacillary angiomatosis. Two types of Rochalimaea have so far been isolated in this disease i.e., R. henselae which is the most frequently involved, and R. quintana. The usefulness of making such a diagnosis resides in the sensitivity of bacillary angiomatosis to antibiotics, emphasing the need to carefully look for the presence of bacterial clusters when atypical angioproliferative lesion appears in patients with AIDS.

AIDS-Related Opportunistic Infections↗
PubMed1994

[Neurothekeoma. General review apropos of an anatomoclinical case with immunohistochemical and ultrastructural study].

The authors report a case of neurothekeoma in a 16-year-old woman. The tumor was located in the dermis of the chin and exhibited a plexiform and multinodular architecture with dense lobules admixed with myxoid areas. Tumor cells were pleomorphic and few atypias and mitoses were seen. On immunohistochemical study, intracytoplasmic staining was observed with anti-vimentin antibody, and, to a lesser extent, with KP1 antibody. Few elements expressed S100 protein. Ultrastructural analysis showed undifferentiated mesenchymal cells. A review of 156 cases (of which 123 cases are reported in two main series) shows that neurothekeoma preferentially affects dermis in cervicofacial areas and shoulders in young women. It has a benign course and recurrence is not seen provided excision is complete. Two main histological varieties are described, i.e. cellular and myxoid, the latter being referred to as nerve sheath myxoma. Diagnostic problems can be raised with other nerve sheath tumors and melanocytic and fibrohistiocytic proliferations. Transition forms between neurothekeoma and neurinoma or neurofibroma are described. Despite confusing immunohistochemical and ultrastructural data, most authors admit that neurothekeoma can express schwannian or perineurial differentiations, and may also be derive from an undifferentiated mesenchymal cell of neural crest origin.

Adolescent↗
PubMed1993

[Osteo-medullary metastases from cerebral glioblastoma].

A 55 year old female with a history of three different malignancies including a cerebral glioblastoma developed two bone metastases (in the spine and iliac crest). Histologic and immunohistochemical studies of biopsy specimens demonstrated the presence of glial fibrillary acidic protein, establishing that the bone tumors were metastases from the glioblastoma. Specific features of these rare metastases are discussed.

Bone Neoplasms↗
PubMed1993

A study of the expression of four chemoresistance-related genes in human primary and metastatic brain tumours.

We investigated four mechanisms of intrinsic chemoresistance in a series of 67 human brain tumours including 31 gliomas (one grade I ganglioglioma, nine grade II and 10 grade III astrocytomas, 11 glioblastomas), 13 cerebral metastases, one medulloblastoma, one malignant teratoma, three ependymomas and 18 meningiomas. We studied four genes by northern blotting: multidrug-resistance (MDR 1), glutathione-s transferase (GST pi), dihydrofolate reductase (DHFR), and topoisomerase II (Topo II). The Topo II gene was absent in the normal adult brain (100%) and in 64% of the tumour samples tested. A second gene, GST pi, was found to be overexpressed in 38% of brain tumours. The two other chemoresistance-related genes were occasionally overexpressed in brain tumours (2% for MDR1, 9% for DHFR). Our results provide evidence that chemoresistance is intrinsic to the brain tissue and seems likely to be a multifactorial process.

Blotting, Northern↗
PubMed1992

Brain-tissue cysts in rats infected with the RH strain of Toxoplasma gondii.

Virulent strains of the coccidian parasite Toxoplasma gondii become attenuated so as to survive and complete their life cycle; however, it is not known whether the attenuation process is attributable to an innate cystogenic capacity of the parasite or to host-induced mechanisms. This report presents direct evidence of RH cystogenesis in non-immunised Fischer rats and subsequent attenuation of RH pathogenicity in non-immunised mice following a single passage through rats. Taken together, these preliminary observations tend to suggest that at least one mechanism of T. gondii involves intermediate host attenuation.

Animals↗
PubMed1992

Central neurocytomas. Critical evaluation of a small-cell neuronal tumor.

We report herein the clinical and pathological features of 20 patients with central neurocytomas. Investigations for various differentiation antigens and cell type-specific markers were performed by immunohistochemistry using paraffin-embedded tissue. In addition, the expression of L1 adhesion molecule and of the various N.CAM (neural cell adhesion molecule) isoforms were investigated by immunoblotting studies in two frozen specimens. Central neurocytomas are clinically characterized by their intraventricular localization, occurrence in young adults, and good prognosis. It rarely occurs in patients over 50, but such cases have a poor prognosis. Total surgical excision is the best treatment. Radiotherapy is appropriate if surgery is incomplete or contraindicated. Histologically, central neurocytomas display the following features: an oligo-like pattern, usually associated with large fibrillary rosettes or perivascular arrangement, and a rich endocrine-type vasculature. Central neurocytomas have a remarkably homogeneous antigenic profile. GFAP expression is only found in scattered reactive astrocytes, S100 protein in reactive astrocytes and rare tumor cells. Among the pan-neuroendocrine markers, central neurocytomas always express neuron-specific enolase; they frequently express synaptophysin but never chromogranin A. Synaptophysin is the most reliable immunohistological marker for central neurocytomas; however, immunoreactivity could be lost with long formalin fixation. In these cases, electron microscopy is used to support the neuronal nature of the tumor cells. The expression of L1 adhesion molecule and the isoform 180 of N.CAM, indicates that central neurocytomas are formed by cells committed to neuronal phenotype. Nevertheless, advanced neuronal differentiation may be absent, as suggested by the persistence of embryonic N.CAM, the nonexpression of neurofilament proteins, and the absence of mature synapses in numerous cases. Central neurocytomas and neuroblastomas share some biochemical properties, but their respective clinicopathological features and biological behavior are dramatically different.

Adolescent↗