Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.21.1 (DNase)
 7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the current study, we found evidence for the existence of binding sites for TRH in synaptic membrane preparations of several regions of the postmortem adult human brain. High levels of specific binding (fmol [3H]Me-TRH/mg protein/2 hr) were found in limbic structures: amygdala (7.1 +/- 0.6, Mean +/- SE), hippocampus (2.8 +/- 0.3), and temporal cortex (2.4 +/- 0.8). Intermediate levels of binding were found in the hypothalamus and nucleus accumbens whereas binding was low to undetectable in frontal and occipital cortex, cerebellum, pons, medulla and corpus striatum. Binding of the radioligand was linear over protein concentrations of 0.05-1.5 mg, and greater than 6 hr of incubation was required to achieve maximal binding. In the amygdala, binding was inhibited in the presence of TRH and Me-TRH but not in the presence of up to 1 microM concentrations of cyclo (His-Pro), TRH-OH, pGlu-His or peptides unrelated to TRH. Pretreatment of amygdala synaptic membranes with detergents, proteases or phospholipases disrupted [3H]Me-TRH binding; pretreatment with DNase or collagenase had no effect on binding. Saturation and association/dissociation analyses of the binding of [3H]Me-TRH to purified amygdala synaptic membranes revealed the presence of a high affinity (KD = 2.0 nM), low capacity (Bmax = 180 +/- 16 fmoles/mg protein) binding site. These results demonstrate that a highly specific membrane associated receptor for TRH is present in the adult human brain. The specific role that this receptor plays in brain function remains to be elucidated.
 ...
PMID:Thyrotropin releasing hormone (TRH) binding sites in the adult human brain: localization and characterization. 609 73

EMT-6 tumors were treated in vivo with 300 kVp X-rays, cyclophosphamide, or bleomycin. Tumor cell suspensions were prepared by digesting tumors with trypsin or a collagenase-deoxyribonuclease-pronase cocktail, and cells were plated in vitro for determination of fractional cell survival. Cell survival after X-rays was identical for the two disaggregation methods. Trypsin-derived cells were far more sensitive to bleomycin but less sensitive to cyclophosphamide than those prepared with the mixed enzyme cocktail. Interaction of drug produced and enzyme caused damage was the probable cause for these discrepancies. The nature of the interaction may be drug specific and therefore unpredictable. The results were unlikely to be due to different nonrepresentative tumor cell samples being produced by the two digestion methods, because the X-ray cell survival curves were so similar for the two products.
 ...
PMID:Effect of tumor dissaggregation on results of in vitro cell survival assay after in vivo treatment of the EMT-6 tumor: x-rays, cyclophosphamide, and bleomycin. 615 35

EMT-6/UW tumours were treated in vivo with X-rays, cyclophosphamide, or bleomycin. Cell survival was assayed in vitro following tumour disaggregation with trypsin or an enzyme cocktail (EC) consisting of pronase, collagenase and DNase which gives a 10-20 x higher cell yield. Surviving fraction was lower after cyclophosphamide treatment for cells isolated with EC than for cells prepared with trypsin. The opposite result was obtained with bleomycin; trypsin-isolated cells appeared more sensitive. In attempting to determine the basis for this discrepancy, it was found that both dissociation methods isolate a non-representative cell sample with fewer cells in DNA synthesis (12-13%) than in the original tumour (approximately 22%). The specific nature of the interaction between the injury caused by drug and enzyme remains to be elucidated.
 ...
PMID:Response of an in vivo-in vitro tumour to X-rays and cytotoxic drugs: effect of tumour disaggregation method on cell survival. 615 76

Co-culture of cancer patients' nonadherent peripheral blood lymphocytes with irradiated autologous fresh tumor cells, termed the mixed lymphocyte-tumor interaction (MLTI) test, resulted in significant stimulation of 3H-Tdr in corporation on day 6 in 19 of 37 autologous combinations. The MLTI test was performed in a microtiter wells (0.2 ml) and a variety of solid tumor cells (sarcomas and carcinomas) were used. Tumor cells were dissociated from the fresh biopsy tissue by nontrypsin enzymatic digestion (deoxyribonuclease, hyaluronidase, and collagenase) and the tumor cells enriched by depletion of macrophages using adherence procedures. Occasionally, further tumor cell purification was achieved by separation of cells on the basis of size on dis-continuous gradients. Positive MLTI resulted in stimulation as high as 20-fold over the backgrounds of PBL and tumor cells cultured alone. Mean positive MLTI was SI of 7.7. The negative MLTI were not a reflection of generalized immunosuppression, because tumor cell preparations that did not stimulate autologous PBL did stimulate allogeneic PBL. In an additional patient, PBL not responding in the autologous MLTI did respond to allogeneic tumors. MLTI using cryopreserved cells reproduced the MLTI results using fresh cells in 11 of 16 tests; the other five tests were all positive in the fresh MLTI and negative when using cryopreserved cells. Despite reports from many other groups it appears that positive MLTI were not tumor-specific. In 14 experiments we were able to simultaneously test the proliferative response to autologous tumor as well as to an autologous normal tissue (lung, liver, colon, and bowel). In eight of these experiments positive responses were obtained with tumor stimulators and in seven of these, positive proliferation was also obtained with normal tissue.
 ...
PMID:The human mixed lymphocyte-tumor cell interaction test. I. Positive autologous lymphocyte proliferative responses can be stimulated by tumor cells as well as by cells from normal tissues. 620 46

Rat sympathetic neurons, plated onto extracellular matrix produced by cultured bovine corneal endothelial cells, rapidly extended neurites in the absence of nerve growth factor (NGF). The response was unaffected by antiserum to NGF. Rapid outgrowth also occurred when sympathetic neurons were plated onto polylysine-coated surfaces that had been exposed to serum-free medium conditioned by corneal endothelial cells (CMSF). A response was seen even when the neurons were cultured without serum. When plated onto a polylysine-coated dish treated with CMSF over half its surface, only the neurons on the treated half extended neurites. The active factor in CMSF was destroyed by trypsin, acid (pH 1.6), base (pH 12.7), or heating to 80 degrees C; it was stable to heating to 60 degrees C, collagenase, deoxyribonuclease, and neuraminidase. The factor elutes just after the void volume of a Sepharose 6B column. In associative cesium chloride gradients, it sediments as a peak centered at a density of 1.36-1.37, corresponding to a peak of material that can be biosynthetically labeled with [35S]sulfate or [3H]leucine. Material from this fraction was inactivated by heparinase, but not chondroitinase ABC, implying that a heparin sulfate proteoglycan is essential for the factor's activity. Inactivation by contaminants in the heparinase preparation was ruled out. Further purification indicated that the active factor may exist as an aggregate containing a heparin sulfate proteoglycan and other molecules. CMSF also promoted neurite outgrowth by other types of neurons. Furthermore, a variety of cell types were shown to produce factors similar to that in CMSF.
 ...
PMID:Characterization of a factor that promotes neurite outgrowth: evidence linking activity to a heparan sulfate proteoglycan. 621 11

After 30 min of intraperitoneal injection of dexamethasone to adrenectomized rats about 15% of the label are incorporated into liver homogenate and only 1% of the cytosol-bound hormone is detected in the cell nuclei. The binding of the "in vitro" injected hormone by the nuclei does not obey the second-order reactions (the Scatchard plots). This is probably due to the existence of various ancillary mechanisms, which control the translocation of the hormone complex into cell nuclei at the level of cytoplasm and nuclear membranes. DNAase I, micrococcal nuclease and endogenous nucleolysis markedly increase the part of the nuclear hormone complex resistant to 0.4 M NaCl. In hepatocyte nuclei obtained by the collagenase method, the content of the 0.4 M NaCl-resistant receptor complex is also increased. The resistance of 0.4 M NaCl was also found in 80% of the glucocorticoid-insensitive nuclear complex from Zajdela ascite hepatoma cells. The changes in interaction of the hormone-receptor complex with nuclear acceptor sites eventually resulting in impaired sensitivity of host tissues to hormonal control can be due to the damage of chromatin structure induced by different influences and tumour growth.
 ...
PMID:[Sensitivity of intranuclear glucocorticoid complex from normal rat liver and Zajdela ascites hepatoma to ionic strength and nuclease treatment]. 626 70

All strains of Legionella pneumophila tested produced detectable levels of extracellular protease, phosphatase, lipase, deoxyribonuclease, ribonuclease, and beta-lactamase activity. Weak starch hydrolysis was also demonstrated for all strains. Elastase, collagenase, phospholipase C, hyaluronidase, chondroitinase, neuraminidase, or coagulase were not detected in any of these laboratory-maintained strains.
 ...
PMID:Extracellular enzymes of Legionella pneumophila. 626 49

Cell suspensions were prepared by either mechanical or enzymatic disaggregation methods from biopsy specimens from 54 patients with various tumors. The biologic activities of cells derived from the two suspensions were then examined. Biopsy specimens of solid tumors were minced, and one-half of each specimen was further processed by being teased with needles, whereas the other half was exposed to a combination of collagenase, hyaluronidase, and DNase. The enzymatic disaggregation method yielded fewer cells per gram of tissue than the mechanical method. However, the percentage of dye-excluding cells was increased by the enzymatic procedure in 93% of the cases. Cells obtained by enzymatic means also had higher cloning efficiencies than those obtained by mincing. The histologic types of cells present in the initial cell suspensions were the same for cells obtained by the enzymatic or mechanical disaggregation methods. The number of colonies obtained was linearly related to the number of cells plated in both cases. The tritiated thymidine suicide indices (estimates of the percentage of cells in the S-phase of the cell cycle) were the same for the two cell populations obtained by the two methods. The results indicate that cells obtained from solid tumors by enzymatic dissociation methods did not differ significantly from cells obtained by the more conventional mechanical techniques. However, cell viabilities and cloning efficiencies were significantly improved by the enzymatic technique.
 ...
PMID:Effect of enzymatic disaggregation on proliferation of human tumor cells in soft agar. 628 27

Production of monodispersed cell suspensions from primary human breast tumors is difficult due to the predominant stromal composition of most breast tumors. Our studies were designed to optimize dispersion of breast tumors of known stromal content and histopathology. In a first series of experiments three enzymatic protocols were compared to disperse minced tissue: (A) treatment with collagenase (2 mg/ml) in the presence of 5% serum for 24 hours; (B) treatment with collagenase (6 mg/ml) and DNase (0.002%) in 10% serum for 3 hours; (C) treatment with collagenase (2 mg/ml) for 3 hours followed by pronase (0.075%) for 1 hour. Protocol A produced better cell yields than B or C for all tumors tested. The monodispersed cells were suspended in a 0.3% semi-solid agar with alpha modified Eagles medium (alpha MEM), 10% serum, and selected hormones, then layered over similarly enriched 0.5% semi-solid agar. The cells prepared by protocol A had a higher plating efficiency and larger average colony size than B or C. In a second series of experiments, protocol A was repeated and compared to two additional procedures: (D) treatment with collagenase (2 mg/ml) and hyaluronidase (1 mg/ml) in the presence of 5% serum for 24 hours; and (E) mechanical disaggregation. Protocol D exhibited a small but significant negative difference from A, while E was the least efficient in producing viable monodispersed cells from the tumors. All enzymatically monodispersed cells produced clonal growth in our agar system. However, mechanically dispersed cells gave growth in only 4 of 7 tumors. Protocol A, in addition to yielding the highest number of viable cells per gram of tissue, gave the highest plating efficiency of all protocols tested.
 ...
PMID:A comparison of methods for the production of monodispersed cell suspensions from human primary breast carcinomas. 630 35

After collagenase treatment of perfused rat liver, isolated washed hepatocytes (parenchymal cells) and washed nonparenchymal cells contained 13-53% and 5-9%, respectively, of the total vitamin A in rat liver. After Pronase E and DNase digestion of liver, nonparenchymal cells contained 1-6% of the total liver vitamin A content. By density-gradient centrifugation, hepatocytes were divided into six fractions, which contained fewer lipid globules per cell and less vitamin A per cell as the cell density increased. In our procedures, lipocytes could not be isolated after either collagenase or pronase E and DNase digestion of liver. Of the total liver vitamin A, 40-80% was found in very low density, vitamin A-containing globules, which have a median diameter of 1.7 microns (range 0.4-4.6 microns), show intense yellow-green fluorescence under UV illumination and contain greater than 95% of their vitamin A in ester form. The distribution of vitamin A among cells and vitamin A globules in rats dosed with vitamin A was the same as in undosed rats. The possible interaction of lipocytes and different classes of hepatocytes in the storage and mobilization of vitamin A is discussed.
 ...
PMID:The storage form of vitamin A in rat liver cells. 631 81


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>