Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Azelaic acid (C9- -dicarboxylic acid) is a competitive inhibitor of tyrosinase and some oxidoreductase in vitro, and in vivo has a beneficial effect on lentigo maligna and malignant melanoma. A definite cytotoxic effect in cultures of malignant melanocytes was also reported. In order to establish if the cytotoxic effect of the diacid is exerted equally in the absence of tyrosinase, lymphoma- and leukemia-derived cell lines were cultured for 72 hr with 10(-3) M, 10(-2) M and 5 X 10(-2) M C9 disodium salt. Normal resting lymphocytes, lymphocytes activated by phytohemoagglutinin, and mouse Balb/c 3T3 fibroblasts were also tested to study a possible effect of azelaic acid on DNA synthesis and cell duplication. At 10(-3) M C9 had no effect on the viability of all the cells tested; at 10(-2) M and 5 X 10(-2) M, C9 2Na had a 50-80% cytotoxic effect on lymphoma- and leukemia-derived cell lines, while at the same concentrations it was not toxic to normal lymphocytes, either resting or stimulated, or to 3T3 fibroblasts. The experiments on cellular incorporation of (1-9 14C) azelaic acid showed that the radiocarbon uptake was two to three times higher for lymphoma- and leukemia-derived cell lines than for lymphocytes, either resting or stimulated, or 3T3 fibroblasts. Biochemical analysis revealed that the diacid underwent beta-oxidation in all the cell cultures. Fractionated centrifugations of 3T3 fibroblasts cultured in the presence of radiolabelled azelaic acid (2 X 10(-4) M) plus cold C9 2Na (10(-2) M), showed that the radioactivity was mainly concentrated in the cytoplasm. The results, being similar to those obtained by adding azelaic acid to cultures of melanoma cells, suggest that the cytotoxic effect of azelaic acid may be due to interference with mitochondrial oxido-reductase enzymes, rather than with tyrosinase. The difference in reaction between lymphoma- and leukemia-derived cell lines and normal or stimulated lymphocytes, and 3T3 fibroblasts, could be explained on the basis of a different degree of permeability of the cell membrane, and/or to a possible different sensitivity of reaction of mitochondrial functions. A similar argument could be used to explain the absence of an effect of dicarboxylic acids upon normal as compared with hyperactive or malignant melanocytes in vivo.
 ...
PMID:Activity of azelaic acid on cultures of lymphoma- and leukemia-derived cell lines, normal resting and stimulated lymphocytes and 3T3 fibroblasts. 400 85

The previously described headspace-gas chromatographic procedure for the determination of acrylonitrile (AN) in several foods, with N/P selective detection, has been modified to include packaged luncheon meats. The loss of AN during equilibration at 100 degrees C in meat samples as well as the previously described loss in cold pack cheese and peanut butter has been studied. The loss of AN could be prevented by the addition of 10% phosphoric acid, which increases the acidity of the food-acid-salt slurry to pH 1.2-1.5. This acidification permits detection of AN at 2 ppb (5% FSD at 16 X 10(-2) amp/mV) in all foods studied. AN was not detected in 10 samples of luncheon meat packaged in AN-based plastic which contained up to 2.6 ppm AN.
 ...
PMID:Improved procedure for determination of acrylonitrile in foods and its application to meat. 401 90

The exchange of essential light chains (SH-LCs) of scallop myosin was followed with the aid of scallop SH-LC alkylated with 14C-labeled iodoacetate. More than 70% of the SH-LCs were exchanged in myosin preparations that were desensitized by removal of both regulatory light chains (R-LCs) with ethylenediaminetetraacetic acid (EDTA) treatment. Although desensitized myosin solubilized with 0.6 M NaCl or with 10 mM adenosine 5'-triphosphate (ATP) in the absence of salt equilibrated rapidly with SH-LCs even in the cold, exchange in myosin filaments required elevated temperatures. Equilibration of the SH-LCs in desensitized preparations did not depend on ATP or magnesium ions but was significantly accelerated by actin. The desensitized myosin preparations containing alkylated SH-LCs (approximately 1 mol of thiol alkylated/mol of SH-LC) readily recombined with R-LCs. The preparations regained fully the calcium dependence of the actin-activated magnesium adenosinetriphosphatase (Mg-ATPase), contained R-LCs and SH-LCs in equimolar amounts, and had an ATPase activity similar to that of untreated myosin preparations. R-LCs interfered with the equilibration of the SH-LCs. In intact myosin preparations, the exchange of SH-LCs was slow and was frequently associated with the dissociation of the R-LCs. The blocking action of the R-LC on SH-LC exchange agrees with evidence showing that the two light chain types interact and suggests that parts of the SH-LC may lie between the R-LC and the heavy chain of myosin.
 ...
PMID:Essential light chain exchange in scallop myosin. 408 45

Unsaturated vitamin B(12)-binding capacity (UBBC) of human serum is not reproducibly measurable because it increases variably in vitro in relation to time, temperature, and, in the case of plasma, anticoagulant present before removal of cells. This variable increase proved to be due to variable release in vitro of transcobalamin III (TC III) from granulocytes. UBBC increase was greatest (up to fourfold normal levels) in the presence of lithium, which is the heparin salt used in many laboratories doing UBBC studies. In vitro increase was least when blood was collected in EDTA at 0 degrees C and immediately centrifuges at 0 degrees C (T(0) sample); results equivalent to T(0) were obtained at room temperature even after several hours delay when 47 mM fluoride was present; either cold temperature or 47 mM fluoride appeared to prevent TC III release from granulocytes. The measured levels of the three transcobalamins with T(0) methods of collection, which presumably reflect most closely the in vivo circulating levels, suggest that TC I and TC III in normal plasms are of the same order of magnitude and together normally comprise less than 10% of the UBBC. Approximately 90% of the UBBC content of sonicates of peripheral blood granulocytes and of bone marrow aspirates of normal individuals appears to be TC III, with the rest being TC I. Thus, normal myelocytes, like normal granulocytes, appear to contain mainly TC III. No TC II was present in any of the sonicates. The general practice in most laboratories has been to determine serum UBBC. Because in vitro increments of up to 119% were found to occur in serum, this practice should be replaced by collection using methods that prevent such increments. Blood collected in EDTA-47 mM NaF had a stable, reproducible UBBC with no significant in vitro increment with time.EDTA-NaF UBBC was 640+/-168 (range 380-921 pg B(12) bound/ml plasma) for 12 normal adult men and 809+/-232 (range 505-1208) for normal adult women. It presumably approximates circulating UBBC and is substantially below the serum UBBC mean of 935+/-262 (range 611-1506 for the same 12 men) and 1273+/-355 (range 811-2306 for the same 10 women).
 ...
PMID:Studies on derivation of transcobalamin 3 from granulocytes. Enhancement by lithium and elimination by fluoride of in vitro increments in vitamin B12-binding capacity. 420 70

The effect of increasing the intracellular pool of monoolein upon the subsequent uptake and esterification of oleic acid was investigated using in vitro rat jejunal slice techniques. The mucosal pool of monoglyceride was expanded by preincubation of jejunal slices in a monoglyceride-containing bile salt medium at a temperature close to 1 degrees C, which inhibited esterification. Subsequent incubation in micellar [(14)C]oleic acid was performed either at 37 degrees C or in the cold. Monoglyceride preincubation increased [(14)C]oleic acid uptake by about 60% without increasing incorporation of fatty acid into triglyceride. This was not due to inhibition of esterifying capacity nor to changes in oleic acid binding to a mucosal fatty acid-binding protein. It is suggested that under these experimental conditions monoglyceride may modify intracellular pools of fatty acid. However, when monoglyceride and fatty acid were preincubated together, mucosal esterification rates during subsequent incubation at 37 degrees C more than doubled. Implications of these data for present theories of rate-limiting steps in lipid absorption are discussed.
 ...
PMID:Monoglyceride modification of jejunal absorption of fatty acid in the rat. 483 58

1. This paper reports studies on the metabolism of bone from normal chicks and from chicks with vitamin D-deficiency rickets. Both in vitro and in vivo there was an increased incorporation of [(14)C]proline into collagen hydroxyproline by rachitic bone. The proportion of the collagen that was soluble in cold salt solutions was greater with the rachitic bone. These results show that in rickets there is an increased synthesis of bone collagen, but they do not provide any evidence of a defect in the maturation of collagen. 2. Rachitic bone incubated aerobically in vitro consumed more glucose and released more lactate than normal bone. Bone from rachitic chicks treated with vitamin D 48hr. previously had rates of glycolysis that were nearly normal. Though we were unable to show any direct action of vitamin D in vitro, we consider that vitamin D probably has a direct action on bone, possibly related to matrix biosynthesis.
 ...
PMID:Collagen synthesis and carbohydrate metabolism of rachitic bone. 566 40

A ribonuclease-resistant ribonucleic acid (RNA) with a sedimentation coefficient of 12S was obtained by self-annealing influenza virus-specific RNA isolated from infected cells. It had the properties of double-stranded RNA. (i) Sedimentation behavior in sucrose gradient was independent of salt concentration. (ii) Thermal transition profile was sharp; the melting temperature is 83 C in 0.1 SSC (0.15 m NaCl plus 0.015 m sodium citrate) and 98 C in SSC. (iii) Buoyant density in cesium sulfate was 1.58 g/cm(3) compared to 1.64 g/cm(3) for single-stranded RNA. (iv) It gave rise to single-stranded RNA after denaturation. (v) The 12S RNA duplex contained both plus and minus strands of influenza virus. Labeled plus strands could be displaced by extraneous cold plus strands and extraneous (32)P-labeled plus strands could be incorporated into duplex after denaturation and reannealing.
 ...
PMID:Characterization of influenza virus ribonucleic acid duplex produced by annealing in vitro. 581 52

beta-Galactosidase of Streptococcus lactis 7962 was partially purified, and its properties were studied. Enzyme from only this strain of numerous lactic streptococci tested was stable in cell exudates prepared by various means. Cell-free extracts of the 7962 strain were prepared by sonic treatment of washed cells previously grown in presence of lactose to fully induce enzyme synthesis. Protamine sulfate precipitation of the nucleic acids and ammonium sulfate precipitation of protein were used for partial purification of the enzyme. The resulting enzyme, when resuspended in cold (5 C) phosphate buffer, was extremely labile. However, ammonium sulfate in high concentrations (0.85 m) stabilized and stimulated beta-galactosidase activity. Sephadex G-200 gel filtration was used to achieve further purification and to monitor homogeneity of the enzyme. Separation of the beta-galactosidase in buffer at 5 C yielded an enzyme elution pattern showing two peaks of activity. However, addition of the enzyme solution in 0.85 m ammonium sulfate to the column equilibrated with the same salt concentration yielded only one peak of enzyme activity. The data suggested that the native enzyme was dissociating into active subunits which were stabilized in the presence of the ammonium sulfate.
 ...
PMID:Purification and properties of Streptococcus lactis beta-galactosidase. 602 31

This study describes changes in morphology of plasmalemma from fast skeletal muscle in the course of tissue disruption and isolation. We find that conditions used to solubilize muscle contractile elements, in the isolation of plasmalemma, including the use of 0.6 M KCl or 0.4 M LiBr in the cold (0-4 degrees C), lead to altered plasmalemma morphology. The intramembrane particles, as revealed by freeze-fracture electron microscopy, become aggregated, leaving large domains devoid of particles. The square arrays in the P face and the complementary "pits" in the E face also become aggregated, sometimes forming sizeable aggregates of square arrays. Thin-section electron microscopy using tannic acid enhancement reveals plasma membrane associated components, on both cytoplasmic and extracellular faces, are largely reduced by the salt treatment. Pyrophosphate and magnesium at lower concentrations, sometimes used instead of high salt, also resulted in particle aggregation, although less pronounced than with concentrated salt solutions. The plasma membrane-associated proteins on both plasma membrane surfaces were likewise decreased by this treatment. Pyrophosphate treatment also separated the basal lamina from the plasma membrane. Incubation of muscle in isoosmotic sucrose does not alter the morphology of the plasmalemma with regard to particle aggregation, diminution of membrane associated components, or separation of the basal lamina. Our observations suggest that membrane-associated protein and/or cytoskeleton constrains the mobility of components in the plane of the membrane and that removal of this constraint leads to aggregation of intramembrane particles.
 ...
PMID:Alterations in the morphology of rabbit skeletal muscle plasma membrane during membrane isolation. 610 May 53

Ribonucleic acid (RNA) synthesis was examined in cold-shocked Bacillus subtilis cells. The cells were grown to mid-log stage, harvested, and cold shocked. RNA synthesis was monitored by the incorporation of [3H]uridine triphosphate or [alpha 32P]adenosine triphosphate into trichloroacetic acid-precipitable material in the presence of all four nucleoside triphosphates. The inhibition of RNA synthesis in cold-shocked cells by lipiarmycin, ethidium bromide, rifampin. or streptolydigin was analyzed using mutant or wild-type cells. Also examined were the effects of temperature, salt concentration, and the addition of polyamines or highly phosphorylated nucleotides. In ultraviolet-irradiated and cold-shocked cells, RNA wynthesis decreased to low levels. The addition of exogenous phi 29 or TSP-1 template to these cells caused a 13- to 20-fold increase in RNA synthesis, as monitored by trichloroacetic acid-precipitable counts. RNA synthesized in the presence of phi 29 deoxyribonucleic acid (DNA) hybridizes mainly to EcoRI fragments A and C of phi 29 DBA, These two fragments direct transcription by purified RNA polymerase in vitro and hybridize to early phi 29 DNA produced in vivo. Our results with TSP-1 DNA in this system indicated that the RNA produced hybridizes to the same fragments as early RNA produced in vivo. Plasmic pUB110 DNA was not transcribed in this system.
 ...
PMID:Transcription of exogenous and endogenous deoxyribonucleic acid templates in cold-shocked Bacillus subtilis. 615 74


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