Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.1 (asparaginase)
 2,695 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

First, lymphocyte transplantation into total body-irradiated rats is discussed. The effect on spleen colony formation caused by the transplantation of untreated lymphocytes, as well as of lymphocytes previously incubated with PHA, or with PHA plus L-asparaginase, or with lymphokines, was studied. Then the effect of the urinary colony-stimulating factor in vitro, and the in vitro feeder-layer activity of leucocytes on colony formation of human and mice bone marrow cells in haematological diseases is dealth with. The injection of rat lymphocytes previously incubated for 24 hours with PHA resulted in a higher number and a larger size of colonies in the spleen of the recipient rats. Lymphocytes preincubated with lymphokines gave rise to the formation of spleen colonies which were larger than those developing after the injection of untreated lymphocytes. When the lymphocytes were previously incubated with PHA plus L-asparaginase, PHA failed to stimulate colony formation in the spleen. The phenomenon is explained by assuming that PHA, as an aspecific stimulator of cell division, initiated the division of CFUs, thus the CFUs content of the preincubated samples increased, resulting in an increase in the number of colonies formed after the transplantation of lymphocytes pretreated with PHA. Another possible explanation is that CFUs division, or their spleen take is enhanced by the immunocompetent lymphocytes activated by PHA, either directly or via soluble mediators produced or released by immunocompetent lymphocytes such as lymphokines. The study of colony-forming cells and colony-stimulating activity in primary myelofibrosis (PM) showed an increase in the number of circulating CFUc in this condition, and an abnormal density of these cells reaching a peak below 1.062. The lowering of CSA in the first two peripheral blood gradient fractions agrees with the observation in the same fractions of a high percentage of CFUc at the expense of the CSC population. Thus, double cell population seems to exist in PM. One is greatly abnormal with a low specific density and high plating efficiency, whereas the other population is almost normal, showing a higher specific density and a lower plating efficiency.
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PMID:Experimental and clinical investigations on stem cell take and colony formation. 2 25

Forty-two patients with chronic lymphocytic leukemia (CLL) were studied for morphology of lymphocytes by light and electron microscopy (EM), in vitro responses of lymphocytes to a battery of physical and chemical agents, overall clinical status, immunologic status, course, and response to therapy. CLL lymphocytes could be classified by EM into four groups on the basis of cell size and nuclear contour and by light microscopy into two groups, small cells and large cells (lymphosarcoma cells). Patient survival did not vary with cell size or morphology as determined by light or electron microscopy. In vitro testing of CLL lymphocytes following exposure to X-ray, PHA, DMSO 2 hr at 43 degrees C, prednisolone, glutaminase, and asparaginase permitted a separation of patients into categories of normal and abnormal in vitro responses. A normal in vitro response predicted a good response to therapy but an abnormal in vitro response did not preclude a good response to therapy. Following therapy, normalization of abnormal EM morphology and in vitro response was seen in some patients. Most patients tested had decreased serum immunoglobulins and abnormal PHA responses. There was a high incidence of infections and second neoplasms. Immunologic deficits could not be correlated with variations in lymphocyte morphology or in vitro response.
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PMID:Chronic lymphocytic leukemia: correlation of clinical course and therapeutic response with in vitro testing and morphology of lymphocytes. 86 70

The role of glutaminase activity of microbial deamidases in the immunodepressant action of these enzymes was studied. Escherichia coli asparaginase, asparagin and glutamin deamidases from Pseudomonas fluorescens and Mycobacterium album were found to have an inhibitory effect on the PHA-stimulated lymphocyte blast transformation. The inhibitory activity of deamidases with the asparaginase-glutaminase ratios 1 : 1.5 and 1 : 1.3 was one order of magnitude higher than that of Escherichia coli asparaginase with the ratio 1 : 0.02. It is assumed that glutaminase activity plays an essential role in the immunodepressant action of deamidases .
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PMID:[Comparison of the immunodepressive action of microbial deamidases from different sources]. 642 45

We evaluated the anti-HIV-1 activity of the T-cell-specific protein inhibitor PEG-asparaginase (PEG-ASNase) in human HIV-1-infected T-cells. We further examined the drug synergism between PEG-ASNase and the protease inhibitor Saquinavir (SAQ), both alone and in combination with nucleoside analog reverse transcriptase inhibitors (NRTI). Our drug synergism studies served as a model for an HIV-induced T-cell lymphoma. Phytohemagglutinin [PHA(+)] stimulated T-cells were infected with HIV-1 and then treated with one or more drugs 90 minutes from the viral exposure. To measure inhibition of viral replication, we examined HIV-1 RT and HIV-1 RNA in the supernatant and intracellularly on day 7 post-infection and drug treatment. Last, we examined the effect of administering drugs immediately after HIV-1 infection of T-cells to simulate treatment after an accidental exposure to the virus. PEG-ASNase, even when used alone, has anti-HIV-1 activity in PHA(+)-stimulated T-cells due to inhibition of protein synthesis. When the drug was used with SAQ, the combination was synergistic in inhibiting HIV-1 RT and RNA in the supernatant and intracellularly by 2.5 log10 in comparison with controls. PEG-ASNase and SAQ were even more effective in inhibiting HIV-1 replication when combined with the NRTI inhibitors azidothymidine (AZT) and (-)-beta-2',3'-dideoxy-3'-thiacytidine (3TC, lamivudine). The addition of ribonucleotide reductase inhibitor, 2-methyl-1H-isoindole-1,3-dione (MISID), further potentiated the antiviral effect of the regimen. HIV-1 RT and RNA analyses showed that the administration of the PEG-ASNase + SAQ drug combination immediately following exposure to HIV-1 completely inhibited the infection of T-cells in our in vitro T-cell model. From these results we conclude that PEG-ASNase is a valuable T-cell-specific protein inhibitor against HIV-1 infection, when used singly or in combination with a protease inhibitor, an RT inhibitor and an RR inhibitor. Since PEG-ASNase is a drug of choice for the treatment of T-cell lymphomas, a combination regimen containing PEG-ASNase could be very effective in the treatment of HIV-1-induced T-cell lymphoma and possibly AIDS. Future studies are needed in HIV-infected and/or HIV-induced T-cell lymphoma patients to investigate these findings.
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PMID:Synergistic antiviral effect of PEG-asparaginase (ONCASPAR), with protease inhibitor alone and in combination with RT inhibitors against HIV-1 infected T-cells: a model of HIV-1-induced T-cell lymphoma. 1128 17