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Biomedical subjects

F Reyes

Publications and source records attributed to F Reyes.

At least 91 records · Page 5Linked to original sources
PubMed1990

Expression of the alpha/beta and gamma/delta T-cell receptors in 57 cases of peripheral T-cell lymphomas. Identification of a subset of gamma/delta T-cell lymphomas.

Fifty-seven cases of peripheral T-cell lymphoma were studied for cell expression of the T-cell receptor (TCR) chains, using monoclonal antibodies specific for the beta chain (beta F1) of the alpha/beta TCR, and for the delta chain (anti-TCR delta-1) of the gamma/delta TCR. Three different patterns were demonstrated: in 39 cases (69%), the phenotype (CD3+beta F1+TCR delta-1-) was that of most normal T cells. A second pattern was found on six cases (10%), which were of CD3+beta F1-TCR delta-1+ phenotype, and in which DNA analysis showed a clonal rearrangement of the delta locus in the five cases studied. It is suggested that these cases are the neoplastic counterpart of the small subpopulation of normal T cells that express gamma delta receptor. It is of considerable interest that these gamma delta lymphomas had unusual clinicopathologic presentations, as one case corresponded to a lethal midline granuloma and the five others to hepatosplenic lymphomas with a sinusal/sinusoidal infiltration in spleen, marrow, and liver. The fact that the distribution of the neoplastic gamma delta cells in the splenic red pulp resembles that of normal gamma delta cells reinforces the concept of a preferential homing of gamma delta T cells to this tissue. A third pattern (CD3 +/- beta F1-TCR delta-1-) was seen in 12 cases (21%), in which, by contrast to normal post-thymic T cells, no evidence of either alpha beta or gamma delta T cell receptor was found.

Antibodies, Monoclonal↗
PubMed1989

Endochitinase from Aspergillus nidulans implicated in the autolysis of its cell wall.

An endochitinase from centrifuged autolyzed cultures of Aspergillus nidulans has been purified 100 times. The enzyme has Mw 27,000, pI of 4.8 units, pH optimum around 5 pH units. It is unstable at temperature greater than 70 degrees C and does not have a cation requirement. It is inhibited by Hg2+, Cu2+, Ca2+ and Ag+ and it does not have muramidase activity. The enzyme depolymerizes chitin rapidly with production of high molecular weight polysaccharides, and then slowly degrades these with production of N,N'-diacetylchitobiose. The enzyme hydrolyzes N,N',N''-triacetylchitotriose with production of N,N'-diacetylchitobiose and N-acetylglucosamine and this hydrolysis is inhibited by other chitin oligomers and N-acetylglucosamine. This enzyme hydrolyzes in the same way the chitin obtained from the cell wall of Aspergillus nidulans.

Aspergillus nidulans↗
PubMed1989

Purification and properties of a 1,3-beta-glucanase from Penicillium oxalicum autolysates.

High 1,3-beta-glucanase activity was detected during autolysis in a culture medium containing Penicillium oxalicum. It was due to the combined action of four enzymes. The purification process for the major enzyme produced a homogeneous band in the SDS polyacrylamide gel that corresponded to a molecular weight of 79,400 daltons. The enzyme pI was 6.3 and it was only active against 1,3-beta-glucans, with a S0.5 of 0.23 mg ml-1 against laminarin. The enzymatic optima were found at pH 4 and 55 degrees C, and instability was evident when pH and temperature were altered. The enzyme was not active against oxidated laminarin and was barely inhibited by glucono-D-lactone. Hg2+, Ag+ and Fe2+ were effective inhibitors. The enzyme was adsorbed by concanavalin-A-sepharose.

Chromatography, Gel↗
PubMed1989

Beta-N-acetylglucosaminidase from Aspergillus nidulans which degrades chitin oligomers during autolysis.

A hexosaminidase from autolyzed cultures of Aspergillus nidulans was purified 196 fold and characterized as a beta-N-acetylglucosaminidase (EC 3.2.1.30). The enzyme has a MW of 190000, a pI of 4.3, and optimum pH of 5.0 and is unstable at temperatures above 50 degrees C. The enzyme is a glycoprotein with 19.5% sugars, mannose being the principal component. It binds strongly to chitin. The enzyme hydrolyzes different substrates. The Ki with the competitive inhibitor 2-acetamido-2-deoxy-D-gluconolactone was independent of the substrate used. The enzyme was inhibited by Hg2+, Ag+, acetate and other organic anions. The kinetics of hydrolysis of chitin oligosaccharides from 2 to 6 units was studied by HPLC. This enzyme is an exoenzyme which degraded chitin oligomers gradually with the production of N-acetylglucosamine. The hydrolysis of N-N'-diacetylchitobiose was inhibited non-competitively by glucosamine and N-acetylglucosamine. In mixtures of chitin oligosaccharides, the hydrolysis of chitobiose was competitively inhibited by each of the other oligomers.

Acetylglucosaminidase↗
PubMed1989

Mediastinal diffuse large-cell lymphoma with sclerosis: a condition with a poor prognosis.

Twenty patients (17 women, three men) with mediastinal diffuse large-cell lymphoma with sclerosis are reported. At the time of diagnosis, the disease was confined to supradiaphragmatic areas in all patients but two, who had kidney involvement (seven were stage I, 11 were stage II, and two were stage IV). A B-cell phenotype was demonstrated in nine of the 11 cases that were analyzed for cell lineage. All patients received an anthracyclin-containing regimen followed by mantle radiotherapy. Analysis of pretreatment characteristics showed that only the extent of disease influences outcome. Moreover, achievement of complete remission (CR) after chemotherapy appears to be a major prognostic factor. Two-year survival was better in patients who reached CR after chemotherapy than in those who did not (100% versus 9%; p less than 0.0001). Overall 2-year and 7-year survival rates were 50% and 33%, respectively. Therefore, localized mediastinal large cell lymphoma with sclerosis should be considered a high-risk subtype of non-Hodgkin's lymphoma in which standard treatment approaches are unsuccessful.

Adolescent↗
PubMed1989

Penicillin amidohydrolases in fungal autolysis.

The production of penicillin G and penicillin V amidohydrolases or acylases (E.C.3.5.1.11) was studied during the autolysis of filamentous fungi in a mineral medium, and in the same medium with phenoxyacetic acid as inducer. In all the studied fungi, enzymes showing penicillin G and penicillin V amidohydrolase activities were found. Generally, an increase of these activities during fungal autolysis was observed. The presence of phenoxyacetic acid in the medium did not increase these activities. The activities found in the culture fluids were generally higher than that found in the mycelial extracts. Under these conditions, beta-lactamases (penicillinases) were not found. The fungi Alternaria alternata, Fusarium culmorum, Penicillium oxalicum, and the species Penicillium 222 were chosen to study penicillin G and penicillin V acylases. The enzymes were precipitated with tannic acid from the culture fluid of their autolyzed cultures. Some kinetic constants of these activities were determined.

Amidohydrolases↗
PubMed1989

Determination of cephalosporin-C amidohydrolase activity with fluorescamine.

A spectrophotometric procedure for the assay of cephalosporin-C amidohydrolase activity, based on the determination of the 7-aminocephalosporanic acid (7-ACA) produced in the hydrolysis of cephalosporin-C by the enzyme, is described. This procedure can be used to detect 7-ACA over a range of 10 to 200 micrograms mL-1. The same method can be used as a fluorometric procedures with a 100-fold greater sensitivity. At pH 4.5 7-ACA produces a strong fluorophor with fluorescamine, detectable spectrophotometrically at 378 nm and fluorometrically at an excitation of 378 nm and emission of 495 nm. At this pH the fluorophors formed with cephalosporin-C, proteins and aminoadipic acid present minimal absorbance values. The conditions for maximal detection of 7-ACA in the presence of proteins, cephalosporin-C and aminoadipic acid have been determined.

Amidohydrolases↗
PubMed1988

Lethal midline granuloma (polymorphic reticulosis) and lymphomatoid granulomatosis. Evidence for a monoclonal T-cell lymphoproliferative disorder.

Lymphomatoid granulomatosis (LG) and polymorphic reticulosis (PR), originally described as distinct entities, now are considered as a single disease process. Common histopathologic features include necrosis, vasculitis, and a granulomatous infiltrate. Such features have led to consider lymphomatoid granulomatosis as a systemic vasculitis; alternatively the possible emergence of an overt lymphoma has suggested that it could be a lymphoproliferative process. To investigate this later hypothesis, the authors analyzed the cellular infiltrate of tissue specimens from two patients with histologic features of LG. The analysis included the study of T-cell antigen expression and DNA rearrangement of the beta T-cell receptor gene. In one patient, the T-cell phenotype of infiltrating cells was abnormal because of antigen loss. In both patients, the cells contained rearranged DNA indicating the presence of a clonal T-cell proliferation. It is concluded that some cases of LG and PR, if not all, are related to a neoplastic T-cell lymphoproliferative disorder.

Adult↗
PubMed1988

Activation by PHA of CD8 lymphocytes into clonal colony forming cells. Role of interleukin-1.

Monoclonal T cell colonies can be grown in agar culture from quiescent T lymphocytes under PHA stimulation, provided that (1) a low number of T lymphocytes (less than or equal to 5 X 10(4)/ml) is seeded, (2) IL-2 is added to the culture, and (3) a high number of accessory B cells (greater than or equal to 5 X 10(5)/ml) is present in contact with the T lymphocytes. Under these culture conditions the colony progenitors can be ascribed to the CD4 subset, whereas CD8 lymphocytes do not generate colonies. This finding is surprising since both CD4 and CD8 lymphocytes may be cloned in liquid culture. We now report the appropriate conditions required to grow cytotoxic CD8 lymphocyte colonies in agar. CD8 colony growth is dependent upon IL-2-IL-2 receptor interaction and is inhibited by anti-IL-2 receptor antibodies. In addition to PHA, accessory B cells and IL-2, an additional signal provided by recombinant IL-1 is necessary for CD8 colony formation. Exogenous IL-1 can be replaced by irradiated CD4 lymphocytes which stimulate the expression of membrane IL-1 activity in the accessory B cells. In addition, colony growth from quiescent but not preactivated CD8 lymphocytes is inhibited by anti-IL-1 antibodies. Altogether, the data show that an IL-1 signal is required for the induction of IL-2 responsive IL-2 receptors on quiescent CD8 colony forming cells.

Animals↗
PubMed1988

Functional analysis of CD8 lymphocytes in long-term surviving patients after bone marrow transplantation.

The recovery of T-cell populations after bone marrow transplantation (BMT) is characterized by a persistent expansion of CD8 lymphocytes. Previously, we have shown that beyond 1 year posttransplantation the CD8 lymphocytes consist, to a large extent, of CD8+ HNK1+ cells that suppress, like normal CD8 lymphocytes, immunoglobulin production in vitro. We have further investigated the functional capabilities of CD8 lymphocytes, mostly HNK1+ (from 50 to 77%), in seven long-term BMT patients. As normal, patient CD8 lymphocytes do not suppress (1) phytohemagglutinin (PHA)-induced interleukin 2 (IL2) receptor expression and IL2 responsiveness by normal T cells or (2) the mixed lymphocyte reaction of donor cells. Also as normal, patient CD8 lymphocytes can be activated into potent cytotoxic effectors. Therefore, under the present experimental conditions, the increase in the absolute number of CD8 lymphocytes in the long-term BMT patients is characterized by an expansion of the CD8+ HNK1+-cell subpopulation and a normal suppressor/cytotoxic potential on a per-CD8+ cell basis.

Bone Marrow↗
PubMed1988

Hairy cell leukemia associated with large granular lymphocyte leukemia: immunologic and genomic study, effect of interferon treatment.

The authors describe a patient who presented an association of hairy cell leukemia (HCL) and large granular lymphocyte (LGL) leukemia. An eventual relationship between these two rare entities is analyzed. Hairy cells (HCs) were present in the blood, bone marrow, and spleen. An excess of LGLs was found only in the blood and bone marrow. After splenectomy the patient received an alpha 2-interferon (alpha 2-IFN) treatment. The HCs surface phenotype was mu+delta+kappa+, CD20+, and CD25+. The LGLs consisted in CD3+, CD8+, HNK1+, WT31+ T lymphocytes. These were absent in the spleen. alpha 2-IFN treatment resulted in the disappearance of the HCs in the blood and bone marrow, whereas the LGLs remained unchanged. Before alpha 2-IFN treatment, peripheral blood cells, predominantly LGLs, exerted low cytotoxicity that increased up to a normal level after treatment. Using Southern blotting the authors studied the rearrangements of the T-cell receptor beta--chain (C beta) and gamma-chain (J gamma) genes and immunoglobulin heavy (JH)- and light (C kappa, C lambda)- chain genes. An unique JH and C kappa gene rearrangement was found in the blood and spleen, whereas C beta and J gamma gene rearrangements were present in the blood, not in the spleen. Under alpha 2-IFN treatment, the JH gene rearrangement fainted dramatically, in contrast to that of the C beta gene. The study of messenger RNA (mRNA) of the T cell receptor alpha and beta chains evidenced the 1.3-kilobase (kb) and 1.6-kb bands in the blood and their absence in the spleen. The patient was human T-cell leukemia virus (HTLV)-II negative by Southern analysis of blood and spleen cells. It is concluded that the LGL expansion was clonal and not reactive to the HCL. Although the authors cannot definitely exclude that both HC and LGL proliferations stem in a common leukemic precursor, their findings support an association of the two entities.

Antigens, Surface↗
PubMed1987

High-grade malignant cutaneous plasmacytoma metastatic to the central nervous system. A case report with electron microscopy, immunohistological, and neuropathological studies.

A case of high-grade malignant extramedullary plasmacytoma (EMP), unusual in its initial cutaneous localization and major involvement in the central nervous system rapidly resulting in death, is reported. Light- and electron-microscopic studies of a skin nodule revealed a high proportion of immature and mature plasmacytes. Immunohistological study revealed that both cells synthesized different amounts of a monotypic cytoplasmic kappa light chain. Neuropathological study revealed extensive infiltration of the leptomeninges and perivascular spaces as far as the deep parenchyma. In several places, effraction of vessels resulted in parenchymatous, tumor-like, plasmacytic infiltration. The findings of this case were compared with those of the few previously reported cases of EMP with initial cutaneous or intracranial localization, and with those of immunoblastic sarcoma occurring in some cases of myeloma.

Brain Neoplasms↗
PubMed1987

Failure of combination chemotherapy of advanced follicular (low-grade) non-Hodgkin's lymphoma.

Twenty-two patients with Stage III and IV follicular non-Hodgkin's lymphoma were treated for 8 months by a chemotherapy regimen alternating between two different four-drug combinations (doxorubicin, teniposide, cyclophosphamide, prednisone; vincristine, cyclophosphamide, CCNU, prednisone). The overall response rate (complete and partial remission) was 68%. The complete remission rate was 23%. Twenty patients are alive, 50% of them are free of disease progression (median follow-up 76 months). It is concluded that our chemotherapy regimen is not satisfactory and that new therapeutic approaches are needed.

Adult↗
PubMed1987

Traumatic segmental bone defects in the upper extremity. Treatment with exposed grafts of corticocancellous bone.

We treated twenty-two consecutive patients for an open fracture and segmental loss of bone in the upper extremity by delayed insertion of a graft of iliac corticocancellous bone. All of the wounds were left open and healed by secondary intention. Sixteen patients (nineteen grafts) had long-term follow-up. Ten injuries were secondary to a gunshot wound. The ten patients (twelve grafts) who had an injury to the hand were followed for an average of 24.1 months. No patient in this group had an infection, and all had primary union after an average of 13.3 weeks. Nine had a satisfactory result. The other six patients (seven grafts) had an injury to the arm or forearm and were followed for an average of 30.2 months. There were four non-unions, one refracture, and no persistent infections. The final result was satisfactory in five and unsatisfactory in one patient. Fourteen of the nineteen grafts were inserted within seventeen days after the initial injury. All nine of the grafts in the hand that were inserted early did well, but three of the other five (in the arm or forearm) became infected. The method that was used in the patients who had an open injury of the hand allowed early active motion and quick rehabilitation. The exposed cortical bone was not prone to infection. The technique has limited application in patients who have an open injury of the arm or forearm because of a high incidence of complications.

Adult↗
PubMed1987

Phenotypic and genotypic heterogeneity in large granular lymphocyte expansion.

The cellular heterogeneity of large granular lymphocyte expansions has been illustrated by the phenotypic and genotypic findings in five patients. In one patient whose circulating cells were CD2+, CD3-, CD5-, CD7+, CD8-, CD11+, Leu7+, CD16+, and displayed strong natural killer activity, no rearrangement of the T cell receptor beta-chain gene and T cell rearranging gene gamma was detected. The four other patients presented with neutropenia without overt lymphocytosis. In these patients the circulating lymphocytes expressed a predominant T cell phenotype CD2+, CD3+, CD5+, CD7+, CD8+, Leu7+. In three of them the presence of a T cell clone was demonstrated on the basis of a unique pattern of rearrangement of the T cell receptor beta-chain genes.

Aged↗
PubMed1987

Vasculitis in hairy-cell leukemia.

Vasculitis associated with hairy-cell leukemia (HCL) has been reported occasionally. We determined the clinical and biological significance of this association by the retrospective study of a series of 50 patients with HCL, including nine patients with vasculitis. The development of vasculitis was not related to a variant of HCL on the basis of hematologic findings and survival. Vasculitis could occur at any time during the course of HCL, and was the circumstance for the diagnosis of HCL in three cases. Clinical and immunohistologic findings were those of hypersensitivity vasculitis in the nine patients. Infection was found to be an associated factor. Thus, eight of nine patients were infected at vasculitis onset, four died of their infection with no remittance of the cutaneous lesions, and three recovered from both infection and vasculitis. The monocyte deficiency in HCL is known to favor intracellular pathogen infection; however, we could not demonstrate that it also correlates with a decrease in the clearance of IgG-sensitized erythrocytes. Finally, vasculitis in HCL appears to be associated with a lasting infection in most cases.

Adult↗
PubMed1986

The kinetics of the autolytic phase of growth in cultures of Aspergillus niger.

The kinetics of the autolytic phase of growth in cultures of Aspergillus niger has been studied. Two different autolytic periods could be distinguished. One, consisting of a rapid (exponential) loss (62%) of mycelial weight, occurred between 36 and 117 hours of incubation. A second, consisting of a slow autolysis, occurred between the 117th and the 190th hour of incubation; the mycelial loss here being 5%. Based on the degree of autolysis (alpha = 67.0%), 92.5% and 7.5% are lost during the first and the second autolytic periods, respectively.

Aspergillus niger↗