ChIP incubation buffer

2007 ◽  
Vol 2007 (11) ◽  
pp. pdb.rec11034-pdb.rec11034
Keyword(s):  
Incubation Buffer

Folate transport by human intestinal brush-border membrane vesicles

1987 ◽  
Vol 252 (2) ◽  
pp. G229-G236 ◽  
Author(s):  
H. M. Said ◽  
F. K. Ghishan ◽  
R. Redha
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicle ◽  
Membrane Vesicles ◽  
Disulfonic Acid ◽  
Folate Transport ◽  
Intestinal Brush Border Membrane ◽  
Transport Carrier ◽  
Incubation Buffer

Transport of folic acid (Pte-Glu) across the brush-border membrane of human intestine was studied using brush-border membrane vesicle (BBMV) technique. The transport of Pte-Glu was higher in BBMV prepared from the jejunum than those prepared from the ileum (0.70 +/- 0.05 and 0.14 +/- 0.02 pmol X mg protein-1 X 10 s-1, respectively). The transport of Pte-Glu appeared to be carrier mediated and was pH dependent and increased with decreasing incubation buffer pH; saturable (Kt = 1.69 microM, Vmax = 4.72 pmol X mg protein-1 X 10 s-1); inhibited in a competitive manner by the structural analogues 5-methyltetrahydrofolate, methotrexate, and 5-formyltetrahydrofolate (Ki = 2.2, 1.4 and 1.4 microM, respectively); not affected by inducing a relatively positive or negative intravesicular compartment; independent of Na+ gradient; and inhibited by 4,4'-diisothiocyanatostlibene-2,2'-disulfonic acid (DIDS), an anion exchange inhibitor. The increase in Pte-Glu transport on decreasing incubation buffer pH appeared to be in part mediated through a direct effect of acidic pH on the transport carrier and in part through the pH gradient imposed by activating Pte-Glu-:OH- exchange and/or Pte-Glu-:H+ co-transport mechanisms. The important role of an acidic extravesicular environment in Pte-Glu transport is consistent with a role for the intestinal surface acid microclimate in folate transport. These results demonstrate that Pte-Glu transport in human BBMV occurs by a carrier-mediated system that is similar to that described for rat and rabbit intestinal BBMV.

scholarly journals The Role of Red Cell Energy Metabolism in the Generation of Irreversibly Sickled Cells In Vitro

Blood ◽  
1973 ◽  
Vol 42 (6) ◽  
pp. 835-842 ◽  
Author(s):  
Michael Jensen ◽  
Stephen B. Shohet ◽  
David G. Nathan
Keyword(s):  
Energy Metabolism ◽  
Calcium Metabolism ◽  
Red Cells ◽  
Red Cell ◽  
Hemoglobin S ◽  
Cell Energy ◽  
Incubation Buffer ◽  
Membrane Defect

Abstract An acquired membrane defect is believed to be responsible for the maintenance of the sickled shape in oxygenated irreversibly sickled cells (ISC), because the hemoglobin S in these cells is not in the aggregated, "sickled" state. In the present study, it is demonstrated that the acquisition of the membrane defect in vitro depends on cellular metabolism. Only if cellular ATP is almost completely depleted while the cells are sickled, do they become unable to resume the biconcave disk shape upon reoxygenation. If calcium is omitted from the incubation buffer, ISCs are not generated despite metabolic depletion. This suggests an action of ATP mediated through calcium metabolism similar to that which prevents membrane stiffening in normal red cells. No ISCs were produced by repeated sickling and unsickling. Thus, a membrane alteration occurring as a consequence of metabolic depletion seems to be a more important factor in the generation of ISC than sickling-unsickling induced fragmentation.

Optimized Determination of γ-Glutamyltransferase by Reaction-Rate Analysis

1974 ◽  
Vol 20 (9) ◽  
pp. 1121-1124 ◽  
Author(s):  
Sidney B Rosalki ◽  
David Tarlow
Keyword(s):  
Dilute Hydrochloric Acid ◽  
Reaction Rate ◽  
Enzymatic Reaction ◽  
Enzyme Reaction ◽  
Enzyme Reactions ◽  
Rate Analysis ◽  
Acid Substrate ◽  
Incubation Buffer ◽  
Optimal Ph

Abstract We describe a method for measuring γ-glutamyltransferase (EC 2.3.2.2) activity in serum, which can be used with automated enzyme analyzers (such as the LKB 8600 Reaction Rate Analyzer) that require enzyme reactions to be initiated with substrate. The method also permits optimal determination conditions to be obtained at 37 °C. The enzymatic reaction is commenced by adding γ-glutamyl-p-nitroanilide dissolved in dilute hydrochloric acid to samples pre-incubated with tris(hydroxymethyl)aminomethane—glycylglycine buffer. The p-nitroaniline liberated is continously monitored at 37 °C at 405 nm. The pH of the pre-incubation buffer is such that the optimal pH for the enzyme reaction results from addition of the acid substrate solution.

Description and Evaluation of Serologic Assays Used in a Multicenter Trial of Acellular Pertussis Vaccines

PEDIATRICS ◽  
1995 ◽  
Vol 96 (6) ◽  
pp. A48-A48
Author(s):  
Bruce D. Meade ◽  
Adamadia Deforest ◽  
Kathyrn M. Edwards ◽  
Theresa A. Romani ◽  
Freyja Lynn ◽  
...  
Keyword(s):  
Multicenter Trial ◽  
Tween 20 ◽  
Incubation Buffer

In the September 1995 supplement, titled Report of the Nationwide Multicenter Acellular Pertussis Trial (1995;96:547-603), two articles contain errors: • Description and Evaluation of Serologic Assays Used in a Multicenter Trial of Acellular Pertussis Vaccines (1995;96:570-575): On page 571, the 14th line under the heading "ELISA" contains an incorrect percentage for Tween-20 in the serum incubation buffer. It should be 0.05% (vol/vol) Tween-20, not 0.5%, as printed.

Incubation Buffer

2013 ◽  
Vol 2013 (7) ◽  
pp. pdb.rec074997
Keyword(s):  
Incubation Buffer

scholarly journals Technical Evaluation of a New Immunoradiometric and a New Immunoluminometric Assay for Thyroglobulin

2002 ◽  
Vol 48 (7) ◽  
pp. 1077-1083 ◽  
Author(s):  
Nils G Morgenthaler ◽  
Juergen Froehlich ◽  
Johann Rendl ◽  
Marita Willnich ◽  
Christine Alonso ◽  
...  
Keyword(s):  
Recurrent Disease ◽  
Horse Serum ◽  
Differentiated Thyroid Carcinoma ◽  
Thyroid Stimulating Hormone ◽  
High Dose ◽  
Serum Thyroglobulin ◽  
Hook Effect ◽  
Thyroid Glands ◽  
Technical Evaluation ◽  
Incubation Buffer

Abstract Background: After removal of differentiated thyroid carcinoma (DTC), serum thyroglobulin (Tg) can indicate persistent or recurrent disease. We describe two novel two-step assays designed to measure low Tg concentrations. Methods: We evaluated prototypes of the new IRMA, DYNOtest® Tg-pluS, and the new immunoluminometric assay (ILMA), LUMItest® Tg-pluS. In the first step, a high-salt incubation buffer leads to dissociation of Tg-Tg antibody complexes in serum and is intended to reduce nonspecific interference and interference of potential Tg autoantibodies in the system. We studied recovery of human Tg (from thyroid glands) added to horse serum. We also studied 58 patients with DTC in whom Tg values under thyroid-stimulating hormone (TSH) suppression and TSH stimulation (without thyroxine) were available. Results: The detection limits were 0.04 μg/L Tg for the IRMA and 0.02 μg/L for the ILMA. Intraassay imprecision (CV) was <10% over the range of the calibration curve in both assays. The day-to-day CV was <20% at 0.2 μg/L for the IRMA and at 0.06 μg/L for the ILMA. No high-dose hook effect was seen with up to 200 000 μg/L added Tg or in dilutions of 12 patient sera with Tg values of 307–38 880 μg/L. Mean recovery of 50 μg Tg/L was 96% in those patients. Among 77 samples with Tg antibody values of 65.2–8150 kilounits/L, recovery by the IRMA was disturbed in 7 cases (9%) and by the ILMA in 9 cases (12%). Tg increased as measured in both assays in 50 of 58 patients after thyroxine withdrawal. Conclusions: The new assays have improved precision for Tg <1 μg/L, and even low measured Tg concentrations respond physiologically to thyroxine withdrawal. The assays are free of a high-dose hook effect up to a Tg concentration of at least 38 000 μg/L and may further reduce Tg antibody interference.

Immunoassay of Ochratoxin A, Using Antibodies Developed Against a New Ochratoxin-Albumin Conjugate

1992 ◽  
Vol 75 (5) ◽  
pp. 824-828 ◽  
Author(s):  
Anna Breitholtz-Emanuelsson ◽  
Gunnel Dalhammar ◽  
Karl Hult
Keyword(s):  
Ochratoxin A ◽  
Immunosorbent Assay ◽  
Preparation Method ◽  
Detection Limits ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Plasma Samples ◽  
Sample Preparation Method ◽  
Ochratoxin Α ◽  
Incubation Buffer

Abstract A derivative of ochratoxin A was linked to bovine serum albumin in such a way that the carboxylic group of ochratoxin A was left unmodified. Lysine was substituted for phenylalanine in ochratoxin A, and the ε-amino group was linked to the protein. The conjugate was injected into 2 rabbits; antibodies against ochratoxin A were developed and used to develop an indirect competitive enzyme-linked immunosorbent assay. The detection limits for ochratoxin A in incubation buffer were 0.07 and 0.02 ng ochratoxin A/mL with the 2 antisera, respectively. Three hundred human plasma samples were purified by a novel sample preparation method and were analyzed by the immunosorbent assay. The detection limits for ochratoxin A in plasma samples were 0.2 and 0.1 ng ochratoxin A/mL with the 2 antisera, respectively. The cross-reactivity of the 2 antiochratoxin A sera was high for the ochratoxin A methyl ester, about 20% for ochratoxin C, and low for (4R)-4-hydroxyochratoxin A, ochratoxin α, ochratoxin B, and 4-hydroxyochratoxin B. No cross-reactivity was seen for phenylalanine and lysine.

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