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Biomedical subjects

F Reyes

Publications and source records attributed to F Reyes.

At least 109 records · Page 6Linked to original sources
PubMed1985

Immunoblastic lymphoma involving the bone marrow in a patient with alpha chain disease. Clinical and immunoelectron microscopic study.

A patient is reported who had disseminated immunoblastic proliferation that emerged during the course of alpha chain disease. This proliferation was characterized by overt marrow invasion together with osseous and neurologic manifestations. On immunoelectron microscopic study, the malignant immunoblasts displayed varying degrees of cytoplasmic maturation and constituted a morphologic spectrum of alpha-chain-synthesizing cells, ranging from immature blasts without endoplasmic reticulum development to relatively mature plasmablasts; alpha chain was not expressed at the surface of these cells. The general features of the overt malignant stage of alpha chain disease are reviewed in reference to this unusual case. The implications of the cellular findings are discussed with regard to the maturation stage of malignant immunoblasts.

Adult↗
PubMed1985

A subset of OKT4+ peripheral T cells can generate colonies containing mixed progeny with OKT4+ helper and OKT8+ suppressor cells.

The membrane phenotype of human T cell colony progenitors and that of their clonal progeny was studied for expression of the T4 and T8 determinants. Using clonal culture conditions, the colonies were grown in semi-solid agar medium from peripheral blood cells. Clonality was assessed using the glucose-6-phosphate-dehydrogenase isoenzyme marker. Combination of this marker with the culture of sorted cell fractions allowed us to ascribe the colony progenitors to a subset of OKT4+ lymphocytes. The progeny consisted of the mixture of single OKT4+, single OKT8+ and double OKT4+8+ cells, as determined by double staining. Double staining was performed on mass-harvested colony cells and on individual colonies expanded in liquid culture with fresh interleukin 2. Expression of the OKT8 positivity on colony cells deriving from OKT4+ progenitors required an interaction with radioresistant OKT8+ cells that were co-cultured with these progenitors. Furthermore, the functional capacities of the cell progeny were assayed on the pokeweed mitogen-driven immunoglobulin production by B cells. It was found that OKT4+ colony cells were helper whereas OKT8+ colony cells were suppressor cells. It is concluded that a subset of OKT4+ peripheral blood T lymphocytes can generate colonies containing both helper OKT4+ cells and suppressor OKT8+ cells.

Antibody Formation↗
PubMed1985

Human mononuclear phagocyte differentiation: a study of the U-937 cell line by ultrastructural cytochemistry and surface antigen analysis.

U-937 represents a well-established permanent human haematopoietic cell line, which exhibits characteristics of the monocyte/macrophage series. U-937 cells were investigated by peroxidase ultrastructural cytochemistry in order to determine the normal developmental stage to which they correspond. This study was performed in non- and TPA-stimulated cells, in conjunction with surface analysis by monoclonal antibodies. It is concluded: (1) peroxidase-positive U-937 cells are monoblasts and promonocytes involved in myeloperoxidase synthesis; (2) TPA-stimulation caricatures transformation of these cells into monocytes but not into resident macrophages, as far as peroxidase cytochemistry is concerned; (3) the reactivity of myeloperoxidase present in the endoplasmic reticulum of synthesizing cells is inhibited by glutaraldehyde fixation.

Antigens, Surface↗
PubMed1985

Mechanism of accessory cell requirement in inducing IL 2 responsiveness by human T4 lymphocytes that generate colonies under PHA stimulation.

PHA-driven monoclonal colony formation by low concentrations of resting T4 lymphocytes in agar culture requires the presence of interleukin 2 (IL 2) and accessory cells. Using recombinant IL 2 and anti-Tac monoclonal antibody as a probe for the IL 2 receptor, we demonstrate that the requirement of accessory cells (here an irradiated B cell line) in inducing IL 2 responsiveness relies on their enhancing effect in functional IL 2 receptor expression by the T colony progenitors. Furthermore, it is shown that cell to cell interaction between accessory cells and colony progenitors results in IL 2 response, i.e., colony formation, when the IL 2 receptor density reaches a critical threshold. The asynchronism in IL 2 responsiveness expression by the T colony progenitors upon activation and the short-lived T cell-accessory cell interaction, due to accessory cell death, determine the 10% colony efficiency of the culture system. In addition, we demonstrate that the accessory function in IL 2 receptor and IL 2 responsiveness expression by the T colony progenitors can be supported by irradiated T lymphocytes as well as B cells. The absence of lineage restriction of the signal delivered by accessory cells, and the requirement of physical interaction between T colony progenitors and accessory cells, emphasize the necessity of cross-linking the activation-signal receptors in inducing IL 2 responsiveness by resting T4 cells.

Antibodies, Monoclonal↗
PubMed1985

Liberation of electrolytes during the induced autolysis of Aspergillus niger.

The induced autolysis of Aspergillus niger was studied by suspending mycelia in water; after 120 hours there was a 50% reduction in dry weight. The kinetics of the liberation of electrolytes during autolysis was studied, and a positive correlation was observed between the electrical conductivity of the autolizate and autolysis loss of mycelium dry weight.

Aspergillus niger↗
PubMed1984

Heterogeneous accessory cell requirement for human peripheral blood T lymphocyte activation by PHA into IL-2-responsive colony-forming cells.

Mitogen-driven T cell proliferation in liquid culture requires accessory cells that cooperate in interleukin 2 production. We have investigated the accessory cell requirement for human lymphocyte colony formation under PHA stimulation. Semisolid medium limits cell-to-cell contact emphasizing the role of cooperating cells both in growth factor production and in triggering events. Culturing at high T cell density demonstrates that accessory cells can be substituted for colony formation by exogenous IL-2. Culturing at low T cell density in the presence of IL-2 also demonstrates that accessory cells are required for activation of a subset of progenitors into IL-2 responsive colony-forming cells. Consequently, T colony progenitors, contained in the E-rosetting cell fraction of peripheral blood, are heterogeneous in their triggering signals: a minor subset is directly inducible by PHA, and a major subset is inducible by PHA in the presence of accessory cells. We found that monocytes and some leukemic B cells support effective accessory function in both colony growth factor production and colony progenitor sensitization.

B-Lymphocytes↗
PubMed1984

Immunological characterization of the leukemic megakaryocytic line at light and electron microscopic levels.

Twenty cases of leukemia involving platelet precursors have been identified by a panel of monoclonal and polyclonal antiplatelet antibodies and by the ultrastructural demonstration of platelet peroxidase (PPO). The two techniques were in close agreement both for identification and for the quantitation of the blast cells except in three cases where PPO was present in the absence of the immunological markers. The immunological appearance of the leukemic megakaryocytic precursors was identical to that of their normal counterparts; the cells were positive with J 15 (anti GP IIb-IIIa complex), C 17 (anti GP IIIa), J 2 (anti GP 26,000) AN 51 (anti GP Ib). A diffuse cytoplasmic labelling was observed with anti factor VIII vwF and anti platelet factor 4 (PF 4). In addition, the leukemic maturation was quite similar to normal megakaryocyte differentiation since in micromegakaryocytes the expression of Gp Ib was strong and an intense granular pattern of labelling with anti factor VIII vwF and anti PF 4 was observed. In no case was the leukemic megakaryocytic series labelled by anti-erythroid antibodies, anti myeloid antibodies or J 5, B 1, OKT 11 antibodies. Using ultrastructural immunoferritin with J 15 it was possible to demonstrate that labelling with this antibody only occurred on PPO-positive cells. Immunogold or peroxidase labelling with AN 51 at the EM level in cases of mixed leukemia showed that Gp Ib was absent from proerythroblasts and myeloblasts. Therefore, in no case were specific platelet markers expressed in the leukemias of other cell lineages.

Antibodies, Monoclonal↗
PubMed1984

Phenotype study of fresh and cultured hairy cells with the use of immunologic markers and electron microscopy.

The phenotype of fresh and cultured leukemic cells from patients with hairy cell leukemia was studied using a panel of monoclonal antibodies in addition to the detection of peroxidase activity under electron microscopy. In fresh samples, the leukemic cells from 11 patients displayed predominantly a B phenotype, as judged by their reactivity with the B1 monoclonal antibody and surface immunoglobulin expression. Ultrastructural peroxidase activity, characteristic of hairy cells, was observed in all cases studied. When hairy cells were cultured in the presence of phytohemagglutinin and irradiated T cells, their phenotype converted from surface Ig+, B1+, OKT3-, OKT11- to surface Ig-, B1+, OKT3-, OKT11+. In contrast, the peroxidase activity remained unchanged. Some hairy cells were also OKM1+, but no conclusion could be made about the MO2 antigen, a more specific marker of monocytes. The variability of the phenotype in vivo and in vitro indicates that reliable markers are required for identifying hairy cells. When studied together, the staining by B1 monoclonal antibody and the ultrastructural detection of peroxidase, enable the identification of hairy cells with certainty.

Antibodies, Monoclonal↗
PubMed1983

Early response to chemotherapy as a prognostic factor in Hodgkin's disease.

In 164 patients with Hodgkin's disease staged between 1973 and 1979 the response to the 3 initial cycles of multiagent chemotherapy was evaluated as a prognosticator of survival. Treatment of localized disease (Stages I, II, III1) consisted of 3 cycles of chemotherapy followed by subtotal nodal irradiation, including the splenic area in non splenectomized patients. Treatment of extended disease (Stage III2 and IV) consisted of 6 cycles followed by low-dosage radiotherapy of initial bulky disease. Five-year actuarial survival was 88% in Stage I, 80% in II, 100% in III1, 45% in III2 and IV. Chemotherapy-induced complete remission after 3 cycles (CH leads to CR) was associated with a favorable prognosis. Five-year survival of Stage III2 and IV patients was better in those who reached CH leads to CR than in those who did not (75% versus 25%; P less than 0.01). This relationship between CH leads to CR and five-year survival was confirmed in patients with localized disease, as shown in Stage II patients (respectively 97% versus 63%; P less than 0.05). Therefore the response to initial chemotherapy provides a new prognostic factor that may serve to delineate a "high-risk" group of patients. The latter deserve aggressive therapy while those in the favorable group would benefit from a less aggressive combined regimen that would minimize long-term complications.

Antineoplastic Agents↗
PubMed1983

[Multiple myeloma with high tumoral mass. Treatment combining melphalan, cyclophosphamide, vincristine, CCNU and prednisone. 35 cases].

The results of a combination chemotherapy trial (melphalan, CCNU, vincristine, cyclophosphamide) involving 28 patients with stage III (n = 21) or stage II (n = 7) multiple myeloma suggest a high response rate, with a mean 71% malignant cell destruction in 78.5% of the patients. A longer survival in responsive stage III patients as compared with patients treated with alkylating agents seems likely, but this can only be established by a randomized trial. Despite haematological side-effects, this combination therapy may be used in high risk patients, especially those resistant to a single alkylating agent and in whom the frequency, intensity and duration of responses appears to be the same as in previously untreated patients. In contrast, only one of the 7 patients treated for relapse after previous response to a single alkylating agent responded to the combination chemotherapy.

Adult↗
PubMed1983

Adult T-cell lymphoma leukemia in Western countries.

A new T-cell disorder has recently emerged: the so-called adult T-cell lymphoma leukemia (ATLL) initially described in Japan. Subsequently, ATLL cases were recognized in patients from the Caribbean. We summarize the clinical and hematological features of 19 published cases from Western countries, in addition to a new case we encountered. The leukemic cells display characteristic morphological features and a T3+T4+T8-T6- surface antigenic phenotype. Overall survival is of short duration, but remission could be obtained in our case despite a subsequent relapse in skin and CNS. Geographic clusters of ATLL cases have led to the discovery of the possible role of a new retrovirus, HTLV, in the genesis of this rare malignancy.

Adult↗
PubMed1983

Lytic enzyme activity in autolysing mycelium of Aspergillus niger.

We have studied changes in the activity of some lytic enzymes contained in mycelium of Aspergillus niger in cultures relative to the autolytic phase of growth. Acid phosphatase, polygalacturonidase and alpha-amylase activity reached its highest level (40.7, and 8 U/sample, respectively) at the initiation of the autolytic phase of growth. 1.3-beta-Glucanase and beta-N-acetylglucosaminidase reached its highest level (3.5 and 2 U/sample, respectively) during the first days of autolysis. Alkaline phosphatase, cellulase, invertase, esterase, chitinase and proteolytic activity is also present in autolysing mycelium of A. niger, though comparatively low. Their maximum activity coincided with the beginning of the autolytic phase of growth. In all enzymes studied here, as autolyis proceeded, enzyme activity decreased by about 90%. Only esterase activity remained nearly constant throughout the whole period of autolysis described here.

Acetylglucosaminidase↗
PubMed1983

Expression of an accessory cell phenotype by hairy cells during lymphocyte colony formation in agar culture.

Human T lymphocytes require the cooperation of accessory cells to generate lymphocyte colonies in agar culture under PHA stimulation. Various hairy cell enriched fractions, as well as normal monocytes, have been found to be able to initiate colony formation by normal lymphocytes. Leukemic monocytes from CMML patients were also effective, but not the leukemic lymphocytes from CLL patients. The phenotype expressed by HC in agar colonies was further studied using cell surface and enzymatic markers. We have concluded that HC in agar culture in the presence of both normal T lymphocytes and PHA lose the B phenotype that they express in vivo and function like an accessory cell in contrast to normal or leukemic B lymphocytes.

B-Lymphocytes↗
PubMed1983

Phenotype study with monoclonal antibodies of T lymphocyte colonies in normal individuals and in patients with chronic OKT8+ lymphocytic leukaemia.

The lymphocyte colony forming capacity of peripheral blood mononuclear cells from normal controls and from two patients with chronic OKT8+ lymphocytic leukaemia was determined in agar culture under PHA stimulation. The number and size of the colonies in patients were reduced compared to normal. The lymphocytic phenotype of colony cells was studied with monoclonal antibodies in colonies harvested from agar culture and in colonies expanded in liquid culture in the presence of TCGF. This study was performed in individual colonies and in pooled colonies. Colonies from normal controls contained a mixture of the OKT4+ and OKT8+ lymphocyte subsets. In contrast, colonies from the two patients contained essentially OKT4+ lymphocytes. The data indicate that, in the patients, progenitors of the OKT8+ subset are unresponsive to normal proliferative and/or differentiative stimuli under the present culture conditions.

Aged↗
PubMed1982

Cell wall degradation in the autolysis of filamentous fungi.

A systematic study on autolysis of the cell walls of fungi has been made on Neurospora crassa, Botrytis cinerea, Polystictus versicolor, Aspergillus nidulans, Schizophyllum commune, Aspergillus niger, and Mucor mucedo. During autolysis each fungus produces the necessary lytic enzymes for its autodegradation. From autolyzed cultures of each fungus enzymatic precipitates were obtained. The degree of lysis of the cell walls, obtained from non-autolyzed mycelia, was studied by incubating these cell walls with and without a supply of their own lytic enzymes. The degree of lysis increased with the incubation time and generally was higher with a supply of lytic enzymes. Cell walls from mycelia of different ages were obtained. A higher degree of lysis was always found, in young cell walls than in older cell walls, when exogenous lytic enzymes were present. In all the fungi studied, there is lysis of the cell walls during autolysis. This is confirmed by the change of the cell wall structure as well as by the degree of lysis reached by the cell wall and the release of substances, principally glucose and N-acetylglucosamine in the medium.

Aspergillus nidulans↗
PubMed1982

Myelofibrosis and acute megakaryoblastic leukemia in a child: topographic relationship between fibroblasts and megakaryocytes with an alpha-granule defect.

In a child with acute megakaryoblastic leukemia--severe thrombocytopenia and myelofibrosis, EM studies on bone marrow showed a strict topographic relationship between the presence of clusters of abnormal megakaryocytes and the increased number of fibroblasts and extracellular fibers. Megakaryocytes and platelets lacked alpha-granules while the plasma thromboglobulin level was three times the normal level. This suggested that the alpha-granular proteins were synthesized but not retained in alpha-granules. If this occurs, the increased marrow levels of platelet-derived growth factor and factor 4 would favor the proliferation of fibroblasts and the synthesis of collagen, and thereby promote myelofibrosis. After therapy-induced remission, the number of marrow megakaryocytes decreased, the alpha-granules were normally produced, the plasma beta-thromboglobulin level was normal and the myelofibrosis disappeared. These observations suggest that during acute megakaryoblastic leukemia, an acquired gray-platelet syndrome occurs and that the local excretion of alpha-granule proteins triggers the myelofibrosis.

Blood Platelets↗