PubMed Health⌕ Search

Biomedical subjects

M Diocee

Publications and source records attributed to M Diocee.

7 recordsLinked to original sources
PubMed1994

Loss of anionic sites on the glomerular basement membrane in transplant glomerulopathy.

We studied anionic sites on the glomerular basement membrane in patients with chronic renal transplant rejection having clinical and histological features of transplant glomerulopathy. All patients had significant proteinuria (greater than 1 g/24 h as well as light- and electron-microscopic features very like focal segmental glomerulosclerosis, though no patient had that disease in the native kidney. A significant reduction in the density and absolute number of anionic sites was observed compared with controls and with patients having stable graft function. The findings suggest that the loss of anionic sites may play an important part in the pathogenesis of transplant glomerulopathy.

Anions↗
PubMed1993

Intracytoplasmic lumina in squamous epithelial lesions of the oral cavity.

Intracytoplasmic lumina are considered a diagnostic feature of adenocarcinomas and have not been reported in squamous cell carcinomas. We are documenting intracytoplasmic lumina in a case of primary squamous cell carcinoma of the oral mucosa and in the oral squamous mucosa in two cases of graft versus host disease, confirming that intracytoplasmic lumina are also present in squamous epithelia and their tumors. Likely explanations for the presence of intracytoplasmic lumina in non-neoplastic and malignant squamous cells of the oral cavity include multiple differentiation, phagocytosis and immune attack on desmosomes.

Adolescent↗
PubMed1993

Major histocompatibility complex class II-restricted cytotoxicity by self-myelin basic protein-reactive T-cell hybridomas: evidence for a tumour necrosis factor-independent nucleolytic mechanism.

Direct cytotoxicity by class II-restricted T cells has been proposed as a potential mechanism in autoimmune tissue damage, as well as in immunoregulation. We used I-A(s)-restricted non-granular cytotoxic T-cell hybridomas (BP24.29 and BP47.7), specific for self-determinants on myelin basic protein (MBP), and different monoclonal targets, in order to characterize the mechanism of killing used by these cells. An early lesion at the level of the target cell nucleus was indicated by the fact that target DNA lysis ([3H]thymidine release) proceeded 2-2.5-fold as rapidly as cytoplasmic lysis (51Cr release) over the first 14 hr after stimulation. Cytotoxicity was relatively resistant to inhibition by anti-calcium agents (TMB-8 and verapamil), even under conditions which blocked interleukin-2 (IL-2) release. Although tumour necrosis factor (TNF) has been proposed as one mediator of class II-restricted cytotoxicity, these cells (i) released no detectable TNF after stimulation with antigen, concanavalin A (Con A), or anti-CD3, (ii) readily lysed TNF-resistant targets (A20 and LS-102.9), and (iii) had no cytotoxic effect on TNF-sensitive cells (L929). Substantial 'bystander' killing of I-A-mismatched targets was observed, which was 13-37% of the cognate (I-A(s)-restricted) cytotoxicity measured in parallel. This finding may indicate an effector mechanism in autoimmune demyelination, since the myelin-forming oligodendrocytes of the central nervous system are not inducible for major histocompatibility complex (MHC) class II expression.

Animals↗
PubMed1987

Demonstration of Epstein-Barr virus in immunoblastic sarcoma of B-cells arising in a child with primary immunodeficiency disease.

The subject of this investigation was an 11-month-old infant girl who presented with a pathological fracture of the right femur due to a metastasis from an abdominal immunoblastic sarcoma. Her past history included recurrent, intractable bacterial and fungal infections. Investigations of her immune status revealed low numbers of T-lymphocytes, a reversed T-helper (TH)/T-suppressor (TS) cell ratio, no response of her peripheral blood lymphocytes to pokeweed mitogen, phytohemagglutinin, concanavalin A, and Candida albicans, and an inability of her cells to react in a mixed lymphocyte culture. Serum levels of IgG, IgM, and IgA were all below normal. No thymic shadow was visible on the chest radiograph. There was no evidence of adenosine deaminase or nucleoside phosphorylase deficiencies. The tumor cells exhibited both surface IgM and IgG, and many of the cells contained large amounts of cytoplasmic IgM. Light chain specificity was restricted to lambda chain for both surface and cytoplasmic immunoglobulin. Ultrastructural study of the tumor cells revealed the presence of both intranuclear and cytoplasmic virions in roughly 1% of the tumor cells. These viral particles strongly resembled herpes viruses. DNA-hybridization studies on the neoplasm revealed the presence of 7-10 genome equivalents of Epstein-Barr virus-DNA per tumor cell.

Abdominal Neoplasms↗
PubMed1986

Malignant intracranial fibrous histiocytomas. Histologic, ultrastructural and immunohistochemical studies of two cases.

Two cases of malignant intracranial fibrous histiocytoma are presented. In Case 1 the tumour arose from the meninges and showed a disseminated spread throughout the neuroaxis. In the second case the tumour appeared to arise from within the brain substance. In this case surgical intervention and radiotherapy appeared to have achieved a cure, since no residual tumour was found at autopsy. The tumours were examined using ultrastructural and immunohistochemical techniques, which appeared advantageous in delineating this rare tumour from other intracranial neoplasms.

Aged↗
PubMedDate not supplied

Congenital ependymoblastoma presenting as a sacrococcygeal mass in a newborn: an immunohistochemical, light and electron microscopic study.

We describe a case of congenital ependymoblastoma presenting as a subcutaneous mass in the sacrococcygeal area of a newborn male. The tumor was composed of primitive cells disposed in compact sheets and cords and exhibiting focal ependymal differentiation. No other line of cellular differentiation was identified by either immunohistochemistry or ultrastructural study. Elevated serum alpha-fetoprotein was found, which decreased following surgical extirpation of the tumor. We propose that this tumor had its origin in the ependymal medullary vestige, similar to other sacrococcygeal ependymomas.

Antigens, Neoplasm↗