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Biomedical subjects

J M Scheiff

Publications and source records attributed to J M Scheiff.

At least 37 records · Page 2Linked to original sources
PubMed1995

A rat monoclonal anti-(human CD2) and L-leucine methyl ester impacts on human/SCID mouse graft and B lymphoproliferative syndrome.

The transfer of human peripheral blood mononuclear cells (hu-PBMC) from adult Epstein-Barr-virus(EBV)-seropositive donors in SCID (severe combined immunodeficiency) mice frequently leads to the development of a human B lymphoproliferative syndrome (hu-BLPS). Therefore, as 90% of adult potential donors are EBV-seropositive, efforts have to be made to avoid the occurrence of this B lymphoproliferative disorder. McCune et al. [Science 241:1632 (1988)] used human fetal organs for a human SCID graft. This system does not give rise to hu-BLPS but human fetal organs are much less available than peripheral blood leucocytes. The experiments reported in this paper show how crucial is the presence of functional T lymphocytes for a graft to take and for development of hu-BLPS in hu-PBMC-reconstituted SCID mice, since inhibition of T lymphocyte by a rat anti-(human CD2) monoclonal antibody (LO-CD2a) during the first 10 days of the graft prevents successful engraftment of human normal lymphocytes as well as hu-BLPS in SCID mice. The transfer of B cells alone or B cells plus monocytes in SCID mice does not permit either long-term engraftment or development of hu-BLPS. We also demonstrate that hu-PBMC treated with L-leucine methyl ester are less susceptible to the development of hu-BLPS after engraftment in SCID mice than are untreated hu-PBMC. The mechanism of action of L-leucine methyl ester on these cells is discussed.

Animals↗
PubMed1995

Acute myeloid leukemia: lack of predictive value of sequential quantitative MR imaging during treatment.

PURPOSE: To assess the use of magnetic resonance (MR) imaging in monitoring treatment response in patients with acute myeloid leukemia (AML). MATERIALS AND METHODS: Bulk T1 and T2 were determined with at least four MR imaging examinations (strictly timed) during the first 6 weeks of treatment in 29 patients with AML (age range, 16-75 years; 15 female, and 14 male). Bulk T1 and T2 in responder (n = 22) and nonresponder (n = 7) patients were compared. RESULTS: Relative to pretreatment bulk T1 values, bulk T1 had increased a mean of 11% at week 1 and had decreased a mean of 7% and 39% at weeks 2 and 6, respectively. Values in nonresponder patients were not statistically significantly different (+11%, -14%, -38%). CONCLUSION: MR imaging of lumbar bone marrow in patients with AML demonstrated statistically significant changes in bulk T1 during treatment that correlated with changes in cellularity. However, neither the early increase in bulk T1 nor the rate or magnitude of the subsequent decrease in bulk T1 were indicative of a positive response to treatment.

Adolescent↗
PubMed1995

Cytogenetic analysis of B cell chronic lymphoid leukemias classified according to morphologic and immunophenotypic (FAB) criteria.

609 patients with B cell chronic lymphoproliferative disorder were studied with the primary aim of analyzing the cytogenetic profile of B cell chronic lymphocytic leukemias and, if possible, define correlations with FAB classification of these diseases. Morphological and immunological studies were performed according to criteria proposed by the FAB group. A panel of monoclonal antibodies, including at least sIg, CD19, CD5, and FMC7 was used. Interpretations of morphology and cytogenetics were made independently. When applying strict FAB criteria 65% of the cases could be classified. Most of them (44%) were chronic lymphocytic leukemia (CLL). The cases not satisfying strict FAB criteria could be divided into two groups: one closely related to CLL, and here defined as atypical CLL (aCLL) (21%) and another group consisting of patients with leukemic manifestations of B cell non-Hodgkin's lymphoma (LL) (14%). Analyzable metaphases were obtained in 89% of patients. Clonal abnormalities were present in 35% of patients. The most frequent chromosomal changes were abnormalities of chromosome 11q (60 cases), trisomy 12 (46 cases) and structural rearrangements of chromosome 14q (44 cases). Statistical associations with FAB subtypes were found: aCLL and trisomy 12 (P < 0.00001); mantle zone lymphoma (MZL) and t(11;14) (P < 0.00001) and del(6)(q) (P < 0.0001); CLL/mixed cell type and del(6)(q) (P < 0.002); follicular lymphoma and t(14;18) (P < 0.00001); splenic lymphoma with villous lymphocytes and del(7)(q) (P < 0.0004); leukemic lymphoma (LL) with rearrangements in chromosome 9q (P < 0.0001) and trisomy of 3 (P < 0.001). Chronic lymphocytic leukemia was not statistically associated with any specific chromosomal abnormality. However, this subtype showed a high incidence of del(11)(q) and rearrangements of 13q. This study confirms the value of cytogenetic investigation in the diagnosis of these disorders and may provide some new elements for future refinement of the FAB classification in mature B cell lymphocytic disorders.

Chromosome Aberrations↗
PubMed1994

Haematological disturbances during long-term valproate therapy.

A 14-year-old boy with mental retardation presented with severe thrombocytopenia, macrocytic anaemia and allergic dermatitis. He had been treated with valproate for seizures since the age of 2 years. Clinical examination showed severe purpura, mucous bleeding and extensive dermatitis. Tests to detect serum direct antiplatelet antibodies were positive and bone marrow examination revealed myelodysplastic abnormalities. Valproate was discontinued and both dermatitis and general condition of the child improved with normalization of the full blood count. This report suggests that valproate may produce both peripheral immune thrombocytopenia and severe bone marrow depression several years after the initiation of the therapy.

Adolescent↗
PubMed1994

Two cases of congenital dyserythropoietic anaemia type I associated with unusual skeletal abnormalities of the limbs.

This report describes the cases of two young female patients with congenital dyserythropoietic anaemia (CDA) type I who presented similar hand and foot skeletal abnormalities: lack of distal phalanges and nails, and syndactyly. Up to now, some morphological malformations have been described in association with CDA type I but there is no report of skeletal defects. These two cases are suggestive of a possible association between this hereditary anaemia and specific skeletal abnormalities of the distal extremities.

Abnormalities, Multiple↗
PubMed1993

Thymic nurse cells in culture: morphological and antigenic characterization.

Epithelial monolayers were derived from thymic nurse cells (TNC), and were seeded onto collagen-coated dishes immediately after their isolation from young adult C3H-murine thymuses. Different media and supplements were tested in order to obtain cultures that were as pure as possible. Primary cultures were enriched in epithelial cells but always contained non-epithelial components among which fibroblasts predominated. Immunodetection of keratins, and repeated light- and electron-microscopic observations established the epithelial nature of the elongated cells derived from TNC; these elongated cells were cortical reticular cells, and were different from medullary globular cells that immediately adopted a mosaic pattern in vitro. At the beginning of the culture, the necrosis of cortical lymphocytes appeared to be toxic for epithelial cells; when epithelial cells survived, they showed a temporary lipid accumulation. After a 5-day culture, they still synthesized DNA but lost this capacity thereafter and dedifferentiated. The lympho-epithelial symbiosis appeared to be necessary to maintain some epithelial characteristics of the cultured cells, such as the clear vesicles and the expression of Ia antigens. In sub-cultures, the monolayers were almost purely epithelial in nature but growth was no longer observed. The cells remained reticular in shape, as they were in vivo, but their cytoplasm and their nucleus became larger and numerous cells were multinucleated. Confluence was not obtained with classical media even after mitogenic stimulation. The frequent observation of strongly keratinized areas suggested a process of terminal differentiation; this could not be avoided by using low serum concentration.

Animals↗
PubMed1991

Platelet aggregates in small lung vessels and death during liver transplantation.

10 children who died suddenly during liver transplantation were found at necropsy to have extensive obstruction of small lung vessels by platelet aggregates. In 7 of these patients pulmonary artery pressure changes before death were consistent with acute obstruction of the pulmonary vascular bed. Platelet aggregates were not strikingly increased in blood vessels in other tissues. No single obvious cause for these unusual histological findings could be identified, although the presence of intravascular catheters, perioperative blood and platelet concentrate transfusions, and cellular debris from the liver forced into the circulation during surgery might predispose to platelet aggregation.

Capillaries↗
PubMed1991

Thymic accessory cell complexes in vitro and in vivo: morphological study.

Murine thymic macrophages and interdigitating cells, also called thymic accessory cells, were characterized by means of light- and electron microscopy. The cells were studied in suspension, during isolation by enzymatic digestion and in vivo. They were observed as isolated cells or as components of multicellular complexes, some of which were rosettes and were composed of lymphoid cells centered on each type of accessory cell. We also noted other cell complexes including macrophages that resembled classical epithelial nurse cells. We consider that multicellular complexes represent lymphostromal associations already existing in vivo, because we observed them at the periphery of thymic pieces undergoing enzymatic treatment. The heterogeneity of macrophages that we observed in vitro was also noted in vivo. In vivo macrophages were of three types: classical phagocytic cells distributed throughout the gland, cortical elongated cells in close contact with lymphoid blast cells, and atypical nurse cells containing mitotic cells and located in the inner cortex. The morphological aspects of the latter two cell types suggest that cortical macrophages in vivo have other roles: they can be interpreted as images of positive or negative cell selection. We also believe that rosettes are formed by elongated cortical macrophages when they are enzymatically isolated from the thymus.

Animals↗
PubMed1990

Thymic nurse cells: morphological study during their isolation from murine thymus.

Thymic nurse cells (TNC), which are multicellular complexes composed of epithelial cells and thymocytes, were obtained from C3H-mice thymuses. They were described by means of light and electron microscopy. The morphology of epithelial cells forming isolated TNC compared to that of small tissue fragments obtained by enzymatic digestion revealed that TNC could be derived from all parts of the thymus: cortex, corticomedullary junction and medulla, the cortex being their principal source. This variety of origin, the presence of several epithelial cells inside a single TNC, the presence of non-lymphoid cells, and the various locations of cleaved desmosomes confirmed that their aspect "in vitro" as round and sealed structures can be considered to be an artifact due to the isolation technique used. Indeed, during this procedure, they are formed by a process of wrapping of the epithelial cytoplasm around the tightly associated thymocytes. All three epithelial cell types: cortical reticular cells, medullary reticular cells, and medullary globular cells can form TNC.

Animals↗
PubMed1990

A novel preservation medium protecting prostacyclin production and endothelial integrity of the human saphenous vein graft.

Patency rates of coronary artery saphenous vein bypass grafts can be as low as 50% in the first year after surgery. Of these occlusions, 70% can be attributed to mural thrombus formation. Improvements in surgical handling techniques and in preservation media have improved patency rates, as has the introduction of perioperative antiplatelet therapy. The authors describe a novel preservation medium consisting of heparinized blood from the patient, papaverine and dipyridamole. This medium enhances prostacyclin production and maintains endothelial integrity in preserved saphenous vein segments.

Blood Physiological Phenomena↗
PubMed1990

High amylase activity in pleural fluid and primary bronchogenic adenocarcinoma.

We report a case of primary bronchogenic adenocarcinoma, complicated by pleural effusion, in which very high pleural amylase activity was found, whilst serum amylase was normal. Isoamylase determination showed a salivary-type amylase. Concerning the origin of this enzyme, ultrastructural study of the malignant cells obtained from the pleural fluid suggested a local amylase synthesis. The pathophysiological significance of electron-dense granules found in these cells is also discussed.

Adenocarcinoma↗
PubMed1986

A variant of the congenital dyserythropoietic anaemia type II with structural abnormalities in the granulocytic series.

Typical features of congenital dyserythropoietic anaemia (CDA) were found in a 13-year-old girl admitted for chronic recurrent multifocal osteomyelitis. The findings on light microscopy were in agreement with those described in CDA type II, whereas on electron microscopy, the ultrastructure findings were compatible with both types I and II. The acidified serum lysis test (Ham test) performed with eight normal sera was negative. The patient's red blood cells showed an increased agglutinability with anti-i antibodies. Morphological changes were also shown in the mature neutrophilic granulocyte suggesting that the primary disorder exists already in the multipotent stem cell.

Adolescent↗
PubMed1985

AIDS in two African children--one with fibrosarcoma of the liver.

We report here on two black African girls who developed an acquired immune deficiency syndrome (AIDS). The first patient was a premature girl born to healthy parents. She suffered from interstitial pneumonitis during the first week of life and died of it at the age of 6 months. Her mother, although asymptomatic, had polyclonal hypergammaglobulinaemia, a reversed T-helper/T-suppressor ratio and a decreased lymphocyte response to mitogens. The second patient had the first symptoms at the age of 6 years, developed a primitive malignant fibrosarcoma of the liver at 8 years old and died 1 year later. AIDS can affect black African children who have not been transfused and whose family members are not considered as at a high risk for this disease. In children, AIDS and cancer can be associated. In the second patient, cytotoxic suppressor lymphocytes (OKT8 positive cells) were shown to behave in vitro as precursors of T-killer cells.

Acquired Immunodeficiency Syndrome↗
PubMed1982

[Histologic, ultramicroscopic, and microradiographic study of histiocytosis X lesions in the periodontium].

Examination under an optical microscope of a radiolucent mandibular lesion showed a proliferation of histiocytes. Upon further examination of electron micrographs, the lesion showed the presence of Langerhans cell granules, within the histiocytes, thus confirming the clinical diagnosis of Hand-Schüller-Christian's disease. Microradiographic study of the canine tooth and the surrounding alveolar bone shows alveolar and root resorption, as well as signs of osteomalacia.

Adult↗
PubMed1978

The thymus of Nu/+ mice.

At one month, the thymus weight of NMRI mice heterozygous for the Nu gene was lower than that of the wild type. However, the thymic structure was normal and no significant anomalies at the ultrastructurallevel could be found either in epithelial cells or in thymocytes. Stereologic data showed that the loss of weight was only due to a decrease of the lymphoid population, whereas the absolute number of epithelial cells was unmodified. Several hypotheses that could explain the reduced number of thymocytes were discussed.

Animals↗
PubMed1977

Epithelial cell proliferation in thymic hyperplasia induced by triiodothyronine.

A significant hyperplasia of the thymus was induced in mice, treated with triiodothyronine during the first month of life. Stereological data showed that, in both treated and control mice, mononucleate epithelial cells were four times more numerous in the medulla that in the cortex. After triiodothyronine treatment, their absolute number in both cortex and medulla increased two-fold. The number of thymic epithelial cells could thus be regulated by thyroid hormones. The cortical volume in treated mice was also twice that of controls but medullar volume showed and increase of only fifty percent. Cortical epithelial cells increased at the same rate of the cortex volume by medullary epithelial cells grew more rapidly. In fact the medullary volume enlargement could be be explained mainly by the growth of the epithelium. Medullary lymphocytes did thus not preliferate in the same way as cortical lymphocytes after thyroid hormone administration. The recently described multinucleate epithelial cells were not modified in number and were thus insensitive to thyroid hormones.

Animals↗