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Biomedical subjects

N Janakiraman

Publications and source records attributed to N Janakiraman.

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

Chemokine gene expression in bone marrow stromal cells: downregulation with sodium salicylate.

Chemotactic cytokines, chemokines, have been shown to influence the proliferation of hematopoietic progenitor cells. Thus, regulation of chemokine production by bone marrow accessory cells is a critical aspect of stromal cell regulation of hematopoiesis. We have previously reported that monocyte chemotactic protein-1 (MCP-1 or MCP-1/JE) and interferon inducible protein 10 kD (IP-10) are both induced in murine bone marrow stromal cells +/(+)-1.LDA11 after stimulation with the inflammatory agents interleukin-1 alpha (IL-1 alpha), interferon-gamma (IFN-gamma), or lipopolysaccharide (LPS). In the present study, we have investigated the effect of sodium salicylate, an antiinflammatory agent, on the IL-1 alpha-induced expression of MCP-1/JE and IP-10 genes in stromal cells. Sodium salicylate attenuates the levels of MCP-1/JE and IP-10 mRNA in a concentration- and time-dependent manner. The suppression of MCP-1/JE mRNA is reversible, whereas IP-10 mRNA expression is more or less irreversibly affected as its recovery from the effect of sodium salicylate is slow and partial. Sodium salicylate-mediated suppression of mRNA expression is attributable neither to de novo synthesis of intermediary protein(s) nor to the destabilization of mature mRNA transcripts. On the other hand, sodium salicylate downregulates the transcriptional activity of both genes. Furthermore, IL-1 alpha induces activation of transcription factor nuclear factor (NF)-kB, and sodium salicylate suppresses it in a dose-dependent manner. We conclude that while posttranscriptional events remain unaffected, inhibition of NF-kB activation by sodium salicylate may account for the suppression of chemokine gene expression at the transcriptional level.

Animals↗
PubMed1995

Induction of chemokine mRNA in bone marrow stromal cells: modulation by TGF-beta 1 and IL-4.

Bone marrow stromal cells produce cytokines that are essential for the proliferation and differentiation of hematopoietic stem and progenitor cells. Thus, regulation of cytokine production by bone marrow accessory cells is a critical aspect of stromal cell regulation of hematopoiesis. We have investigated the effect of two cytokines that have been demonstrated to modulate factor production by non-marrow accessory cells (i.e., transforming growth factor-beta 1 [TGF-beta 1] and interleukin-4 [IL-4]) on the induced expression of cytokine mRNA in a bone marrow-derived, cloned, murine stromal cell line +/+/-.LDA11. We showed that +/+/-.LDA11 cells can be induced with lipopolysaccharide (LPS), IL-1 alpha, or interferon-gamma (IFN-gamma) to express mRNA for monocyte chemoattractant protein-1 (MCP-1/JE), IFN-inducible protein-10 (IP-10), stem cell factor (SCF), and macrophage colony-stimulating factor (M-CSF) but not for IL-1 alpha, IL-3, or tumor necrosis factor-alpha (TNF-alpha). The expression of MCP-1/JE and IP-10 mRNA by these inducers was potentiated by TGF-beta 1 and IL-4. The augmentation by TGF-beta 1 of both mRNAs induced with IL-1 alpha was maximum when applied to the cells concurrently with the inducer; the IFN-gamma-induced expression of mRNAs was augmented even if the addition of TGF-beta 1 was delayed. Similarly, IL-4 potentiation of both mRNAs by either inducer progressively increased as the time between exposure to the inducer and exposure to IL-4 increased. Neither modulator altered the time course of mRNA expression by either inducer. TGF-beta 1- and IL-4-mediated augmentation of MCP-1/JE mRNA by IL-1 alpha or IFN-gamma was partially reversed by cycloheximide (CHX), whereas potentiation of IP-10 by either modulator remained unaffected. Increase in the stability of mRNA transcripts by TGF-beta 1 or IL-4 does not appear to play a role in the enhanced accumulation of mRNA in the presence of the modulators. These findings support a role for TGF-beta 1 and IL-4 as critical regulatory molecules in production of MCP-1 and IP-10 chemokines by stromal cells.

Animals↗
PubMed1993

Transforming growth factor beta-1 (TGF-beta 1) potentiates IL1 alpha-induced IL6 mRNA and cytokine protein production in a human astrocytoma cell line.

We analyzed the response of human astrocytoma cell line U373-MG to various cytokines by measuring the production of interleukin-6 (IL6) mRNA and cytokine protein. Interferon gamma (IFN gamma), transforming growth factor beta 1 (TGF-beta 1), granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte-colony-stimulating factor (G-CSF) did not induce IL6 mRNA production; however, IL6 mRNA expression and protein production was strongly induced by IL1 alpha and to a lesser extent by IFN alpha. The IL6 mRNA expression induced by IL1 alpha was potentiated by TGF-beta 1 and IFN alpha and slightly decreased by IFN gamma. The potentiation of cytokine mRNA accumulation by TGF-beta 1 was both time- and concentration-dependent. Induction of IL6 mRNA by IL1 alpha was optimally potentiated either if U373-MG cells were pretreated with TGF-beta 1 or if TGF-beta 1 was added within 30 min after stimulation with IL1 alpha. The potentiation of IL6 mRNA by TGF-beta 1 required de novo synthesis of an intermediate protein since treatment with cycloheximide abrogated the amount of mRNA enhanced by TGF-beta 1 without affecting IL1 alpha-driven mRNA production. Nuclear run-on analyses demonstrated increased transcriptional activity of the IL6 gene when stimulated with IL1 alpha in the presence of TGF-beta 1. However, actinomycin-D pulse chase experiments showed that TGF-beta 1 did not increase the stability of IL6 mRNA. Thus, in concert, the results demonstrate that TGF-beta 1 potentiates IL6 production in astrocytoma cells by promoting the transcriptional activity of the IL6 gene and requires coexpression of new proteins. Since cytokines can provide potent mitogenic signals to tumor cells, the results presented here further suggest that the antitumor effect of combination cytokine therapy might partly depend on heterotypic interactions between tumor cells and cytokines.

Astrocytoma↗
PubMed1991

Peripheral blood stem cell transplantation as an alternative to bone marrow transplantation: an overview.

Stem cells capable of restoring hematopoiesis following lethal bone marrow injury circulate in the blood of many animals, including humans. When collected through leukapheresis and reinfused following high-dose chemotherapy, stem cells offer a treatment option not currently open to some patients who are unable to undergo autologous bone marrow transplantation because of tumor involvement in the pelvis, prior pelvic radiation, or intolerance to general anesthesia. After stem cell infusion, hematologic and immunologic recovery are rapid in comparison to that after autologous bone marrow reinfusion; however, in some cases platelet engraftment is slower. There is some evidence that tumor contamination in the peripheral blood is much less than in the marrow. In any event, most relapses of malignant disease occur at the site of origin and represent treatment failure rather than growth of reinfused malignant cells. Prospective controlled trials are needed to evaluate stem cell in comparison to autologous bone marrow transplantation.

Acute Disease↗
PubMed1991

Assessment of methylprednisolone purging efficacy on Daudi burkitt lymphoma cells from normal bone marrow.

Studies on normal bone marrow and Daudi Burkitt lymphoma cells were performed to determine the efficacy of selective, in vitro chemopurging with methylprednisolone (MP). We found that MP reduces the number of lymphoma cells without significant damage to bone marrow cells. This information is important because we need to improve the existing in vitro purging regimens used to cleanse autologous marrows of metastatic disease before transplantation into cancer patients who have received high-dose chemotherapy. Normal human bone marrow (NBM) and Daudi lymphoma cells were treated in parallel with various purging regimens, NBM death was evaluated using soft-agar culture, while Daudi cell death was evaluated using one-week liquid culture. A protocol of 2.0 mg/mL of MP for four hours demonstrated optimal selectivity. When treatment was followed by cryopreservation, a 1.7 log purge of Daudi cells was increased to 2.3 logs while preserving 36% of committed NBM precursors. We repeated these experiments on a simulated contaminated marrow to model closely the mixture of normal and malignant cells found in advanced, metastatic disease. We evaluated this mixed system by flow cytometric immunoanalysis using the two-color CD10/CD20 markers to detect residual, viable Daudi cells. Our initial results were reproducible in this mixed-cell system, further supporting the evidence for effective in vitro purging of bone marrow using MP.

Bone Marrow Transplantation↗
PubMed1990

Osteomyelosclerosis with granulocytic sarcoma of chest wall. Morphological, ultrastructural, immunologic, and cytogenetic study.

A case of granulocytic sarcoma presenting as a soft-tissue tumor in the chest wall in a patient with osteomyelosclerosis is reported. The tumor mass was detected by a computed tomographic scan during an investigation of the cause of chest pain in a 58-year-old man. Biopsy of the mass showed findings compatible with either a large-cell lymphoma or a granulocytic sarcoma. The latter was confirmed by naphthol-ASD-chloracetate esterase stain and electron microscopic examination. Immunologic study of the tumor mass showed expressions of membrane/cytoplasmic CD 13 and CD 15 antigens. In addition, the tumor cells coexpressed CD 19, although all other T- and B-cell-associated antigens were absent. Cytogenetic study showed translocation t(1;7)(q11;q11) with a net deletion of the entire long arm of chromosome 7 and duplication of the long arm of chromosome 1. Peripheral blood examination showed typical leukoerythroblastosis with teardrop poikilocytosis, large hypogranular platelets, and 0.11 myeloblasts. A bilateral iliac bone marrow biopsy at this time showed osteomyelosclerosis. The patient was treated with hydroxyurea followed by local irradiation, resulting in marked reduction in the size of the tumor and in the pain. He was asymptomatic without any progression in hematologic parameters 10 months after the initial diagnosis.

Humans↗
PubMed1989

Primary fibrinolysis in acute monocytic leukemia.

We present the case of a young man with acute monocytic leukemia (French-American-British classification:M5) and systemic hyperfibrinolysis with severe bleeding. Although fibrinolysis is usually mild and secondary to disseminated intravascular coagulation, its role as a primary and dominant factor in rare cases of leukemia warrants that its presence be sought as a cause of abnormal bleeding. Decreased serum plasminogen and increased serum plasmin determined by synthetic substrate assay and a negative protamine paracoagulation test are crucial findings. Use of high-dose epsilon-aminocaproic acid was effective in treating this complication. A transient increase in fibrinolytic activity coincident with the early effect of antileukemic treatment suggested that plasminogen activator and/or fibrinolytic protease substances were released from leukemic cells. Fibrinolytic activity subsequently disappeared with reduction in the population of leukemic cells.

Adult↗
PubMed1987

Malignant somatostatinoma presenting with diabetic ketoacidosis.

High circulating levels of somatostatin (SRIF) were detected in a patient with a metastatic tumour after development of diabetic ketoacidosis (DKA). Fasting insulin and C-peptide levels were markedly suppressed, but plasma glucagon was not suppressed below normal. Progressive cachexia ensued; at autopsy a poorly differentiated non-small cell neuroendocrine carcinoma metastatic to liver was found. Small gallstones were noted. Electron microscopy of tumour tissue showed neurosecretory granules and tonofilament bundles. Immunohistochemical staining of tumour cells was diffusely positive for carcinoembryonic antigen, bombesin-like immunoreactivity, and calcitonin with focal immunoreactivity for SRIF, serotonin, neuron-specific enolase, chromogranin, and epithelial membrane antigen. Column chromatography of plasma and tumour extract revealed five or more peaks of material with SRIF-like immunoreactivity (SRIF-LI): predominantly SRIF-28 and intermediates in tumour extract, and SRIF-14 and an intermediate between SRIF-28 and SRIF-14 in plasma, DKA in this case of somatostatinoma syndrome may reflect differential effects of tumour production of larger molecular weight SRIF forms on insulin and glucagon secretion.

Adenoma, Islet Cell↗
PubMed1983

Smoldering acute granulocytic leukemia. Observations on its natural history and morphologic characteristics.

In this prospective study, 24 patients with smoldering acute granulocytic leukemia received no specific treatment. Median survival duration from diagnosis was 9.29 months. Fourteen patients died of infection, four died of hemorrhage, two (8%) progressed to aggressive acute leukemia, and three remain alive at 36, 32, and 10 months. No survival predictions could be made from the severity of leukopenia, thrombocytopenia, or both. Neither sepsis nor hemorrhage, as causes of death, segregated into short- or long-term survivors (9.0 and 8.75 months' median survival, respectively). Thirteen patients (59%) had French, American, and British M2 subclassification of acute granulocytic leukemia. The following marrow findings distinguished this entity from preleukemia and other dysplastic states: clustering of stem cells; percentage usually between 20% and 40%; and Auer rods. The use of aggressive chemotherapy v only supportive measures in this condition remains unsolved.

Adult↗
PubMed1977

Pulmonary edema due to tetrachloroethylene.

A patient with massive exposure to tetrachloroethylene fumes presented with coma and severe pulmonary edema. Sequential blood gases, chest x-rays, and clinical findings showed dramatic improvement with conventional but aggressive management and the patient recovered completely. There was no evidence of permanent renal, hepatic, or central nervous system damage.

Adult↗