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M A Rodriguez

Publications and source records attributed to M A Rodriguez.

At least 145 records · Page 8Linked to original sources
PubMed1990

Human IFN-gamma up-regulates IL-2 receptors in mitogen-activated T lymphocytes.

This study examined the role of human recombinant interferon-gamma (rIFN-gamma) in the expression of interleukin-2 receptors (IL-2R) by human T lymphocytes. rIFN-gamma enhanced total numbers of IL-2R in mitogen-activated but not resting T cells. Scatchard plot analysis indicated that rIFN-gamma increased both high- and low-affinity receptors, with a predominant effect on the latter. Phytohaemagglutinin (PHA)-activated T cells treated with IFN-gamma showed higher IL-2 binding and greater IL-2 internalization and degradation than cells treated with PHA alone. There was a corresponding increase of mitogen-driven proliferative responses, indicating an increase of functional receptors in IFN-treated cultures. IFN-gamma may influence T-cell activation and proliferation by enhancing expression of IL-2R and promoting IL-2 uptake by mitogen-activated lymphocytes.

Cells, Cultured↗
PubMed1989

Purification and characterization of acylation stimulating protein.

We have purified to homogeneity and analyzed the amino acid composition of a small (Mr 14,000), basic (pI 9.0) protein from human plasma. This has been named acylation stimulating protein (ASP) because it markedly stimulates triacylglycerol synthesis in human adipocytes. As well, it stimulates triacylglycerol synthesis in human skin fibroblasts cultured from normal individuals. Characteristic saturation curves for the cell metabolic responses to ASP were observed in both cell types with higher stimulation of oleate incorporation into triacylglycerol being observed in adipocytes. The stimulation of triacylglycerol synthesis was much greater with ASP than with insulin. Neither fatty acid binding protein nor albumin was able to mimic the ASP effect.

Adipose Tissue↗
PubMed1989

Distribution of anti-F(ab')2 antibodies and the 16/6 idiotype in systemic lupus erythematosus (SLE) probands and kindreds.

Levels of serum anti-F(ab')2 antibodies and expression of the 16/6 anti-DNA idiotype were studied in 103 sera from first-degree relatives of 17 systemic lupus erythematosus (SLE) kindreds. Among healthy SLE relatives, 35.9% showed anti-F(ab')2 elevations and 24%, Id 16/6 expression. Forty-three and two-tenths percent of healthy SLE relatives with elevated anti-F(ab')2 also showed expression of 16/6; when Id 16/6 was positive, 16 of 25 relatives (64%) showed parallel elevations of anti-F(ab')2. However, within individual families, distribution patterns of elevated anti-F(ab')2 and Id 16/6 often did not coincide. Affinity-isolated anti-F(ab')2 from four members of a single SLE kindred showed relative enrichment for Id 16/6 in only two of the four individuals studied. Moreover, none of the isolated anti-F(ab')2 antibodies within this kindred or another kindred showing 16/6 Id expression reacted directly with 16/6 Id. Our studies suggest that whereas both anti-F(ab')2 and Id 16/6 are increased within SLE kindreds, expression of the two does not always coincide. Furthermore, anti-F(ab')2 antibodies do not show direct reactivity with Id 16/6. A number of anti-DNA idiotypic markers may play a role in idiotypic networks among such SLE kindreds.

Adolescent↗
PubMed1989

The effect of ASP on the adipocyte of the morbidly obese.

The control of triglyceride synthesis within the adipocyte is not fully understood. Insulin is considered to be the most potent stimulant of triglyceride synthesis. In this paper, we report on the effect of a small (14000 Da), basic (pI 9.0) protein isolated from human serum. This protein has been called acylation stimulating protein (ASP). It is a potent stimulant of triglyceride synthesis in adipocytes from both normal weight and morbidly obese subjects. Its stimulatory effect on adipocytes is both rapid, occurring between 15-30 min after the start of incubation, and prolonged, lasting for up to 3 hr. Compared to insulin, it is sixfold more potent in its effect on triglyceride synthesis. As well as acting on isolated cells, ASP also has a fourfold stimulatory effect on triglyceride synthesis in human adipose microsomes at a concentration of 25 micrograms/ml. This study indicates that ASP is a potent stimulant of triglyceride synthesis and therefore may play a role in the pathogenesis of morbid obesity.

Adipose Tissue↗
PubMed1989

Refractoriness to chemotherapy and poor survival related to abnormalities of chromosomes 17 and 7 in lymphoma.

PURPOSE: Lymphoma cells usually show cytogenetic abnormalities, but their relationship to prognosis has not been as extensively studied as in leukemia. A group of previously untreated cases of lymphoma with evaluable metaphases was examined for the association between cytogenetic abnormalities and clinical outcome. PATIENTS AND METHODS: The study consisted of 104 patients, from whom fresh tumor samples were obtained for cytogenetic tests. Because of the complexity of lymphoma karyotypes, the cases were divided into four patterns according to the type of abnormality of chromosome 17 or 7 present. Treatment of patients was given based on histologic grade and stage of disease. Response to treatment was evaluated according to previously described methods. RESULTS: Patients with true abnormalities of chromosome 17 or 7 (defined as those with either structural abnormalities of the short arm of these chromosomes or monosomy of these chromosomes with no associated unidentified markers) were observed to have an adverse prognosis. The overall response rate and tumor-related mortality were less favorable for patients with these cytogenetic abnormalities. By applying multivariate analysis, we found that this observation was independent of the effect of serum lactic dehydrogenase level, histologic grade, or tumor burden. CONCLUSION: True abnormalities of chromosome 17 or 7 in patients with lymphoma are associated with a poor response to chemotherapy, short time to treatment failure, and high tumor-related mortality rate. These findings raise the question of the potential involvement of some gene or oncogene, perhaps the p53 oncogene, which might impart a survival advantage to the malignant cells.

Adult↗
PubMed1989

Auricular chondritis and diffuse proliferative glomerulonephritis in primary Sjögren's syndrome.

Bilateral auricular inflammation with histological changes of relapsing polychondritis was observed in a female patient with primary Sjögren's syndrome. This was accompanied by rapidly progressive renal insufficiency due to diffuse proliferative glomerulonephritis. To our knowledge this is the first well documented case of primary Sjögren's syndrome associated with chondritis and glomerulonephritis, further emphasising the wide spectrum of extraglandular manifestations in this autoimmune disorder.

Ear Diseases↗
PubMed1989

A new serologic staging system for large-cell lymphomas based on initial beta 2-microglobulin and lactate dehydrogenase levels.

We report results of our investigation of prognostic factors for patients with large-cell lymphoma who were entered on the same treatment protocol and who had known pretreatment serum beta 2-microglobulin (beta 2M) and lactate dehydrogenase (LDH) levels. beta 2M and LDH levels were the most significant and independent variables for predicting time to treatment failure (TTF) and survival. The serum level of beta 2M correlated with tumor burden. These two serum markers defined three significantly different prognostic groups. All 27 patients in the low-risk group remain alive and in remission; in contrast, 22 of the 27 patients (81%) in the high-risk group have failed treatment, and only seven (26%) remain alive. In comparison with the Ann Arbor staging system, serum levels of beta 2M and LDH may provide a more precise system for defining risk groups and thereby allow a more rational approach to the development and analysis of treatment strategies.

Adult↗
PubMed1988

Chemotherapy with dexamethasone, high-dose cytarabine, and cisplatin for parenchymal brain lymphoma.

Ten patients with parenchymal CNS lymphoma received combination chemotherapy with dexamethasone, high-dose cytarabine, and cisplatin (DHAP), and additional therapy according to clinical circumstances. Two of four patients with primary CNS lymphoma achieved and remain in complete remission (CR). Four of six patients with CNS lymphoma at relapse also achieved CR. DHAP is active against CNS lymphoma. Further trials with DHAP, particularly in conjunction with other treatment modalities, are warranted.

Adult↗
PubMed1988

Results of recent salvage chemotherapy regimens for lymphoma and Hodgkin's disease.

From 1981 to 1983, 208 patients with recurrent or refractory lymphoma were treated with methylglyoxal-bis-guanylhydrazone (methyl-GAG), ifosfamide, methotrexate, etoposide (MIME). The complete remission (CR) rate was 24% and CR plus partial remission (PR) was 60%. Response was higher for aggressive than for indolent cell types. Median duration of CRs was 16.5 months and median survival of all patients was 9 months. In view of the in vitro synergism between cisplatin and high-dose cytarabine, we recently designed the DHAP regimen, which consists of cisplatin, 100 mg/m2 IV over 24 hours; cytarabine, 2 g/m2 IV over two hours every 12 hours for two doses; and dexamethasone, 40 mg orally daily for 4 days. There were 28 of 90 (31%) CRs and 22 of 90 (24%) PRs. Median duration of CR is 15 months; median survival of all patients is 6 months. The major toxicities have been infection (31%) and moderate to severe renal dysfunction (20%). In contrast to MIME, response rates did not differ significantly between aggressive and indolent cell types. A high-dose regimen (CBV) consisting of cyclophosphamide, 6 g/m2; carmustine, 300 mg/m2; and etoposide, 250 mg/m2 daily for 3 days followed by autologous bone marrow transplant (ABMT) has been successfully used to treat 62 patients with Hodgkin's disease recurrent or refractory after mechlorethamine, vincristine, procarbazine, prednisone, doxorubicin, bleomycin, vinblastine, dacarbazine (MOPP/ABVD)-like regimens. A CR rate (47%) has been observed; 83% of these CRs remain alive and free of disease with a median follow-up of 19 months. This regimen appears to have curative potential in 40% of all cases and in 60% of cases treated after the first or second relapse.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

[Chronic lichenoid keratosis. Apropos of a case].

A male patient of 28 years, with typical clinical features and histopathological changes of keratosis lichenoides (CLK) chronica is described. CLK has some histological features similar to lichen planus, but there are also histological and clinical differences.

Adult↗
PubMed1988

The effect of a plasma protein fraction on lipid synthesis in cultured skin fibroblasts from normals and patients with hyperapobetalipoproteinemia.

Lipid synthesis was measured in cultured skin fibroblasts obtained from normals and patients with Hyperapobetalipoproteinemia (HyperapoB). Using lipoprotein-deficient serum medium, triglyceride synthesis and cholesterol esterification were greater in normals than in HyperapoB due to differences in de novo synthesis, not to differences in re-esterification or to different rates of hydrolysis. When normal and HyperapoB cells were incubated in serum-free medium, however, lipid synthesis was the same. Serum was then fractionated chromatographically and a partially purified protein fraction shown to be responsible for the stimulatory effect in normals.

Adult↗
PubMed1987

Immunoaffinity purification of HTC rat hepatoma cell plasminogen activator-inhibitor-1.

Incubation of HTC rat hepatoma cells with the synthetic glucocorticoid dexamethasone rapidly inhibits tissue-type plasminogen activator activity by inducing a specific plasminogen activator-inhibitor (PAI-1). Using immobilized polyclonal antibodies raised against HT-1080 human fibrosarcoma PAI-1, we have purified HTC PAI-1 from serum-free medium conditioned by dexamethasone-treated HTC hepatoma cells and shown it to be antigenically related to human PAI-1. Greater than 100-fold purification with greater than 75% yield was achieved in a single step. The purified PAI-1 migrates on SDS-polyacrylamide gels as a single major band of 49 kDa with a minor band of 46 kDa. Digestion of PAI-1 with endoglycosidase F causes a shift toward faster migrating species which retain inhibitory activity. The purified PAI-1 was stable at pH 2.5, lost 50% of its activity after 15 min at 45 degrees C, and showed marked activation after treatment with SDS or guanidine-HCl. Purified PAI-1 rapidly inhibited and formed complexes with both tissue-type and urokinase-type plasminogen activators. Polyclonal rabbit antirat PAI-1 antibodies were raised which immunoprecipitate both free and complexed PAI-1.

Amino Acids↗
PubMed1987

Stimulation of fatty acid uptake and triglyceride synthesis in human cultured skin fibroblasts and adipocytes by a serum protein.

Lipoprotein deficient serum has been shown to enhance lipid synthesis in cultured normal human skin fibroblasts incubated in the presence of oleate-albumin. The factor responsible is nondialyzable and trypsin sensitive. The stimulation is proportional to the concentration of lipoprotein deficient serum in the media and is present at all oleate concentrations and incubation times assayed. The protein has been partially purified by column chromatography to yield a Peak II fraction which stimulates triglyceride synthesis in both fibroblasts and isolated human adipocytes. The stimulation is dependent on the concentration of protein fraction and increases to an apparent saturation level of 200% in fibroblasts. Triglyceride synthesis, however, increases to a much greater extent in adipocytes and did not demonstrate saturation at the maximum Peak II protein concentration assayed. These results suggest that human serum contains a protein which stimulates fatty acid uptake and esterification by adipose tissue.

Adipose Tissue↗
PubMed1987

Helper activity by human large granular lymphocytes in in vitro immunoglobulin synthesis.

In the present study we have examined the effect of human large granular lymphocytes (LGL) from healthy donors on Ig synthesis by autologous B lymphocytes. The results showed that this cell population has a consistent helper activity in pokeweed mitogen-activated cultures even when added at very low numbers. LGL can mediate their effect by secreting soluble helper factors capable of modulating B-cell responses as evidenced by the enhancement of IgG and IgM production by supernatants obtained from LGL cultures. Preincubation with interferon gamma further potentiated the helper activity by LGL.

Antibodies, Monoclonal↗
PubMed1986

Abnormal immunoglobulin and rheumatoid factor synthesis by blood lymphocytes in patients with primary Sjögren's syndrome.

Peripheral blood B lymphocytes from patients with primary Sjögren's syndrome showed significantly higher spontaneous synthesis of IgG, IgM, and IgM rheumatoid factor in vitro, compared with B lymphocytes from healthy controls. Lymphocytes from patients also showed higher IgM rheumatoid factor production after mitogen stimulation. Patients had competent suppressor activity for IgG, but not for IgM synthesis. Pre-irradiation of T cells, but not depletion of OKT8+ cells, markedly enhanced IgG synthesis in cocultures with autologous B cells; therefore, the T lymphocyte responsible for this effect is radiosensitive and is not identified by OKT8. OKT8+ lymphocytes from patients did not suppress Ig synthesis by autologous B plus T cell cocultures. However, OKT8+ cells from normal controls down-regulated Ig synthesis by B plus T cells from patients. The abnormal proportion of helper and suppressor cells suggests that there is altered redistribution of regulatory subpopulations in peripheral blood from Sjögren's syndrome patients.

Adult↗
PubMed1984

Inhibition of rheumatoid factor production by non-steroidal anti-inflammatory drugs.

The effects of NSAIDs on IgM rheumatoid factor production in vitro and on serum rheumatoid factor concentration in vivo were investigated using indomethacin (5.0 micrograms/ml), carprofen (10 micrograms/ml). IgM rheumatoid factor was isolated from lymphocytes of patients suffering from rheumatoid arthritis. NSAIDs inhibited IgM rheumatoid factor production in vitro. Furthermore, serum IgM rheumatoid factor was reduced when NSAIDs were administered in vivo. It is thought that NSAIDs effectively remove suppressor T-cells from the tonic inhibitory action of PGE2. This previously unrecognized action of NSAIDs may be a factor in their efficacy in rheumatoid arthritis.

Anti-Inflammatory Agents↗