Because commercial heparin preparations were somewhat inconsistent in properties (45) and [Mn.sup.2+] was observed to interfere with the early enzymatic assays, this combination was generally displaced for routine use by dextran sulfate or phosphotungstic acid
, both used together with [Mg.sup.2+].
Summary: In this study, we report the one-pot synthesis of 2-amino-3,5-dicarbonitrile-6-thio- pyridines with benzaldehyde, malononitrile, and thiophenol by using phosphotungstic acid
as an efficient catalyst in aqueous media.
In addition to electron microscopic evidence of mitochondrial proliferation was helpful in diagnosis; in addition to that, Phosphotungstic Acid
Hematoxylin staining was often useful in identifying oncocytes.
Briefly, to 0.3 mL of serum was mixed 2.4 mL of 0.08 N H2SO4 and 0.3 mL of 10% phosphotungstic acid
. After being allowed to stand at room temperature for 5 min, the mixture was centrifuged at 1600 g for 10 min.
For example, no decrease was observed in a 50% tissue culture infective dose (TCI[D.sub.50]) of poliovirus samples after they were mounted on the grid and stained with 2.5 mM (1.6%) phosphotungstic acid
, pH 7.0.
Specifically, butylated hydroxytoluene (BHT), tetramethoxypropane, TBA, and phosphotungstic acid
were from Fluka.
Serum TC was done using kit AGAPPE diagnostics, TG using Enzyme calorimetric test and HDL-C using Phosphotungstic Acid
Bacteria were negatively stained for 2 min with 1% phosphotungstic acid
(pH 7.4) on carbon-Formvar (Electron Microscopy Sciences, Fort Washington, PA) copper grids as previously described (26,27).
Briefly, 50 [micro]L of reagent I (80 g/L phosphotungstic acid
and 10 mmol/L EDTA in 0.2 mol/L MES buffer, pH 5.3) was added to 50 [micro]L of serum.
Principle: Phosphotungstic acid
is reduced by uric acid in presence of sodium carbonate (alkaline medium) to give a blue complex (tungsten blue) which absorbs light at 700 nm.
Serum triglycerides was estimated by glycerol-3-phosphate oxidase method (11), HDL was estimated by phosphotungstic acid
precipitation method (12), LDL and VLDL were calculated by Friedewald's formula as follows (13):
Before analysis, the samples were diluted 1: 5 and negatively stained with 2% (w/v) phosphotungstic acid
for 30 s and then placed on copper grids precoated with a thin film of polyvinyl formaldehyde for observation.