scholarly journals DETERMINATION OF HISTAMINASE ACTIVITY IN HISTOLOGIC SAMPLES AND ITS QUANTITATIVE DISTRIBUTION IN INTACT HUMAN PLACENTA AND UTERUS

1967 ◽  
Vol 15 (8) ◽  
pp. 431-435 ◽  
Author(s):  
RONALD E. GUNTHER ◽  
DAVID GLICK
Keyword(s):  
Human Placenta ◽  
Diamine Oxidase ◽  
Enzymatic Oxidation ◽  
Optimal Conditions ◽  
Rat Stomach ◽  
Stomach Mucosa ◽  
Tissue Sections ◽  
Peritoneal Mast Cells ◽  
Histaminase Activity

The spectrophotometric method for determination of histaminase, based on measurement of the hydrogen peroxide formed by the enzymatic oxidation of histamine, was modified and adapted to studies on microliter volumes of tissue (placenta) homogenates and microtome sections of tissue (human uterus and attached intact placenta at term). Optimal conditions for these assays were established. From analyses of tissue sections, peak enzyme activities were observed in the decidua, thus supporting the concept that this tissue is a significant source of the increased enzyme in blood plasma during pregnancy in the human. Inhibitor studies with aminoguanidine sulfate showed that the histaminase investigated in the human placenta was diamine oxidase. No histaminase activity was detected in isolated peritoneal mast cells from the rat or in homogenates of rat stomach mucosa.

Determination of diamine oxidase (histaminase) activity. An interference of aldehyde metabolizing enzymes

1978 ◽  
Vol 8 (4) ◽  
pp. 388-389 ◽  
Author(s):  
A. Fogel ◽  
T. Biegański ◽  
J. Wozniak ◽  
Cz. Máslinski
Keyword(s):  
Diamine Oxidase ◽  
Metabolizing Enzymes ◽  
Histaminase Activity

Spectrophotometric study of the complexation equilibria of cadmium ions with 5-bromo and 5-chloro derivatives of 2-(2-pyridylazo)-5-diethylaminophenol (BrPADAP, ClPADAP)

1983 ◽  
Vol 48 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Miroslav Macka
Keyword(s):  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Graphical Analysis ◽  
Optimal Conditions ◽  
Cadmium Ions ◽  
Brij 35 ◽  
Ethanol Medium ◽  
Triton X ◽  
Derivatives Of

The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the reactions of formation of the ML and ML2 complexes of both reagents with cadmium(II) ions were determined by graphical analysis and numerical interpretation of the absorbance-pH curves by the modified SQUAD-G program. Optimal conditions were proposed for the spectrophotometric determination of Cd in 10% v/v ethanol medium in the presence of 0.1% w/v Triton X-100 or 1% w/v Brij 35. BrPADAP and ClPADAP are the most sensitive spectrophotometric reagents for the determination of cadmium(II) ions (ε = 1.28-1.44 . 105 mmol-1 cm2 at 560 nm and pH 8.0-9.5) with a high colour contrast in the reaction (Δλmax ~117 nm) and a selectivity similar to that of other N-heterocyclic azodyes (PAR, PAN, etc.).

Spectrophotometric study of the reactions of lanthanoids with bromopyrogallol red in the presence of cation active tensides

1982 ◽  
Vol 47 (2) ◽  
pp. 503-508 ◽  
Author(s):  
Irena Němcová ◽  
Pavla Plocková ◽  
Tran Hong Con
Keyword(s):  
Absorption Spectra ◽  
Photometric Determination ◽  
Spectrophotometric Study ◽  
Ternary Complexes ◽  
Optimal Conditions ◽  
Bromopyrogallol Red ◽  
Binary Complexes

The absorption spectra of the binary complexes of lanthanoids with bromopyrogallol red were measured and the formation of ternary complexes with cation active tenside, Septonex, was studied. Optimal conditions were found for the formation of these complexes and the possibility of their use in the photometric determination of lanthanoids was demonstrated on several examples.

The polarographic and voltammetric determination of 2,6-dicyano-4-nitro-2'-acetylamino-4'-diethylaminoazobenzene

1990 ◽  
Vol 55 (6) ◽  
pp. 1508-1517 ◽  
Author(s):  
Jiří Barek ◽  
Dagmar Civišová ◽  
Ashutosh Ghosh ◽  
Jiří Zima
Keyword(s):  
Azo Dye ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Determination Limit ◽  
Polarographic Reduction ◽  
Hanging Mercury Drop Electrode ◽  
Optimal Conditions ◽  
Pulse Polarography ◽  
Pulse Voltammetry

The polarographic reduction of the title azo dye was studied and optimal conditions were found for its analytical utilization in the concentration range 1 . 10-6 - 1 . 10-7 mol l-1 using differential pulse polarography and 1 . 10-6 - 1 . 10-8 mol l-1 using fast scan differential pulse voltammetry or linear scan voltammetry at a hanging mercury drop electrode. When the latter technique is combined with adsorptive accumulation of the studied substance on the surface of the hanging mercury drop, the determination limit can be further decreased to 3 . 10-9 mol l-1.

Manufacturing Process for Extracting Essential Oils from White Pepper (Piper nigrum L.) by Hydrodistillation Technique

2019 ◽  
Vol 298 ◽  
pp. 89-93 ◽  
Author(s):  
Thien Hien Tran ◽  
Thi To Quyen Ngo ◽  
Thi Kim Ngan Tran ◽  
Tri Duc Lam ◽  
Tan Phat Dao ◽  
...  
Keyword(s):  
Essential Oil ◽  
Essential Oils ◽  
Manufacturing Process ◽  
Oil Extraction ◽  
Piper Nigrum ◽  
Optimal Conditions ◽  
Distillation Process ◽  
White Pepper ◽  
Oil Performance

Vietnam is the world's leading country in growing and producing pepper trees. In this study, we attempted the optimization of white pepper essential oil extraction. The obtained oil was then subject to determination of constituent composition via GC-MS method. The essential oil performance achieved 3.6% by hydro-distillation process with optimal conditions (25 grams of fresh pepper, size 18, 120 minutes extraction, 130°C). A total of 23 volatile constituents were identified from the white pepper essential oil, with the major components being 27.4% of Limonene, 3-Carene 22,928%, Sabinene 17,622%, β-pinene 10.068%, α-Pinene 5.426%.

The impact of acid hydrolysis conditions on carbohydrate determination in lignocellulosic materials: a case study with Eucalyptus globulus bark

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ricardo Jorge Oliveira ◽  
Bruna Santos ◽  
Maria J. Mota ◽  
Susana R. Pereira ◽  
Pedro C. Branco ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Eucalyptus Globulus ◽  
Industrial Processes ◽  
Lignocellulosic Materials ◽  
Optimal Conditions ◽  
Hydrolysis Conditions ◽  
The Impact ◽  
Eucalyptus Bark

Abstract Lignocellulosic biomass represents a suitable feedstock for production of biofuels and bioproducts. Its chemical composition depends on many aspects (e.g. plant source, pre-processing) and it has impact on productivity of industrial bioprocesses. Numerous methodologies can be applied for biomass characterisation, with acid hydrolysis being a particularly relevant step. This study intended to assess the most suitable procedures for acid hydrolysis, taking Eucalyptus globulus bark as a case study. For that purpose, variation of temperature (90–120 °C) was evaluated over time (0–5 h), through monosaccharides and oligosaccharides contents and degradation. For glucose, the optimal conditions were 100 °C for 2.5 h, reaching a content of 48.6 wt.%. For xylose, the highest content (15.2 wt.%) was achieved at 90 °C for 2 h, or 120 °C for 0.5 h. Maximum concentrations of mannose and galactose (1.0 and 1.7 wt.%, respectively) were achieved at 90 and 100 °C (2–3.5 h) or at 120 °C (0.5–1 h). These results revealed that different hydrolysis conditions should be applied for different sugars. Using this approach, total sugar quantification in eucalyptus bark was increased by 4.3%, which would represent a 5% increase in the ethanol volume produced, considering a hypothetical bioethanol production yield. This reflects the importance of feedstock characterization on determination of economic viability of industrial processes.

scholarly journals Micellar Electrokinetic Chromatographic Study of the Separation of an Aromatase Inhibitor and a Tryciclic Antidepressant in the Breast Cancer Treatment

2008 ◽  
Vol 3 ◽  
pp. ACI.S939 ◽  
Author(s):  
J. Rodríguez Flores ◽  
A.M. Contento Salcedo ◽  
L. Muñoz Fernández
Keyword(s):  
Micellar Electrokinetic Chromatography ◽  
Solid Phase ◽  
Background Electrolyte ◽  
Kinetic Studies ◽  
Breast Cancer Treatment ◽  
Chromatographic Study ◽  
Optimal Conditions ◽  
Sodium Dodecylsulphate ◽  
Experimental Parameters

Micellar electrokinetic chromatography (MEKC) was investigated for the simultaneous determination of letrozole, imipramine and their metabolites in human urine samples over a concentration range of therapeutic interest. Experimental parameters such as pH of the running electrolyte, sodium dodecylsulphate (SDS) concentration, borate concentration, voltage, etc were investigated. Under optimal conditions of 25 mM SDS, 15 mM borate buffer (pH 9.2), 15% 2-propanol, as background electrolyte; 28 kV and 40 °C, as voltage and cartridge temperature, respectively; resolution between the peaks was greater than 1.7. Before the determination, a solid phase extraction (SPE) procedure with a C18 cartridge was optimized. Good linearity, accuracy, precision, robustness and ruggedness were achieved and detection limits of 12.5 ng/mL for letrozole and its metabolite and 37.5 ng/mL, were obtained for imipramine and their metabolites. Real determinations of these analytes in two patient urines were carried out. Sensitivity achieved in this method is sufficient to perform kinetic studies in humans.

Fluorometric determination of uric acid in bovine milk

2010 ◽  
Vol 77 (4) ◽  
pp. 438-444 ◽  
Author(s):  
Torben Larsen ◽  
Kasey M Moyes
Keyword(s):  
Heat Treatment ◽  
Uric Acid ◽  
Xanthine Oxidase ◽  
Bovine Milk ◽  
Oxidase Inhibitor ◽  
Enzymatic Oxidation ◽  
Fast Method ◽  
Xanthine Oxidase Inhibitor ◽  
Milk Samples

The primary objective of this study is to validate a new fast method for determination of uric acid in milk. The method is based on an enzymatic-fluorometric technique that requires minimal pre-treatment of milk samples. The present determination of uric acid is based on the enzymatic oxidation of uric acid to 5-hydroxyisourate via uricase where the liberated hydrogen peroxide reacts with 10-acetyl-3,7-dihydroxyphenoxazine via peroxidase and the fluorescent product, resorufin, is measured fluorometrically. Fresh composite milk samples (n=1,072) were collected from both Jersey (n=38) and Danish Holstein (n=106) cows from one local herd. The average inter- and intra-assay variations were 7·1% and 3·0%, respectively. Percent recovery averaged 103·4, 107·0 and 107·5% for samples spiked with 20, 40 or 60 μmof standard, respectively, with a correlation (r=0·98;P<0·001) observed between the observed and expected uric acid concentrations. A positive correlation (r=0·96;P<0·001) was observed between uric acid concentrations using the present method and a reference assay. Storage at 4°C for 24 h resulted in lower (P<0·01) uric acid concentrations in milk when compared with no storage or samples stored at −18°C for 24 h. Addition of either allopurinol (a xanthine oxidase inhibitor) or dimethylsulfoxide (a solvent for allopurinol) did not affect milk uric acid concentrations (P=0·96) and may indicate that heat treatment before storage and analysis was sufficient to degrade xanthine oxidase activity in milk. No relationship was observed between milk uric acid and milk yield and milk components. Authors recommend a single heat treatment (82°C for 10 min) followed by either an immediate analysis of fresh milk samples or storage at −18°C until further analysis.

Separation and determination of reduced vitamin C in polymerized hemoglobin-based oxygen carriers of the human placenta

2014 ◽  
Vol 43 (3) ◽  
pp. 152-156 ◽  
Author(s):  
Gang Chen ◽  
Ling Mo ◽  
Shen Li ◽  
Wentao Zhou ◽  
Hong Wang ◽  
...  
Keyword(s):  
Vitamin C ◽  
Human Placenta ◽  
Oxygen Carriers ◽  
Polymerized Hemoglobin
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