Showing papers on "Phosphotungstic acid published in 1973"
TL;DR: An anomalous reaction was interpreted as the result of a decomposition of the metal into two altogether different chemical compounds: phospho-11-tungstic acid and free tungstates, which are known to be excellent complexing agents with carbohydrates.
Abstract: Phosphotungstic acid was used at different hydrogen ion concentrations and combined with glycogen and lysozyme, which were used as model systems for carbohydrates and proteins, respectively. Furthe...
47 citations
TL;DR: The composition of mouse sarcolemma is found to be a complex composed of the myofiber cell membrane, a thin zone external to the cell membrane that contains groups that bind colloidal iron and thorium at low pH and a thicker amorphous layer that fails to stain with colloidal Iron andThorium atLow pH.
Abstract: A variety of cytochemical methods were used to investigate the composition of mouse sarcolemma. We found that the sarcolemma is a complex composed of the myofiber cell membrane, a thin zone external to the cell membrane that contains groups that bind colloidal iron and thorium at low pH and a thicker amorphous layer that fails to stain with colloidal iron and thorium at low pH. The entire complex is periodic acid-Schiff-positive and stains with ruthenium red and strongly acid solutions of phosphotungstic acid. Although the specificity of these cytochemical stains is controversial, data obtained with them and from preliminary analyses of myofiber external lamina (EL) indicate that the myofiber cell coat is chiefly composed of glycoprotein containing a large number of carboxyl groups. The EL within the subneural apparatus of the neuromuscular junction differs from noninnervated areas in the fusion of Schwann cell and myofiber EL, the absence of collagen microfibrils, the more intense binding of divalent cations and the less intense stain with phosphotungstic acid in strongly acid solutions.
29 citations
27 citations
TL;DR: Results are compatible with the view that much of the staining of surface material by acidic PTA could be due to the presence of sialic acid residues within surface coat glycoprotein.
22 citations
TL;DR: Experimental results demonstrate that experimental results come up in fact to the expectation that HPEtreated DDD-stained cells show the opposite effect of HPE, which means a left sided asymmetric distribution curve of their E101 values, for HPE causes a decrease of PSH.
Abstract: metric distribution curve. This indicates that not all of the cells have been attacked by HPE to the same extent but that, on the contrary, some of them must have been attacked much more than the others. If this assumption is true one should expect that HPEtreated DDD-stained cells show the opposite effect; that means a left sided asymmetric distribution curve of their E101 values, for HPE causes a decrease of PSH,. Figure 2a and b demonstrates that experimental results come up in fact to this expectation.
15 citations
TL;DR: Results from trypsin and pronase digestions of thin sections indicate that phosphotungstic acid stains cell coat glycoprotein and that there is protein at the cytoplasmic surfaces of membranes.
10 citations
Journal Article•
7 citations
TL;DR: Formaldehyde, in quantities used to preserve uric Acid standard solutions, will introduce errors in the automated analysis of serum uric acid by the Technicon N-13b phosphotungstate procedure, by retarding the dialysis rate.
Abstract: Formaldehyde, in quantities used to preserve uric acid standard solutions, will introduce errors in the automated analysis of serum uric acid by the Technicon N-13b phosphotungstate procedure, by retarding the dialysis rate. It will also diminish recovery of uric acid when these solutions are added to serum. The mechanism of interference is complex and may involve alteration of dialysis rates, formaldehyde— protein—uric acid interaction, and possibly a competing redox with phosphotungstic acid.
6 citations
TL;DR: The staining reactions of various normal organelles were studied as well as a number of pathological alterations including Alzheimer neurofibrillary tangles, eosinophilic rod- like structures, corpora amylacea, lamellar bodies and honeycomb-like structures in the axoplasm.
Abstract: The ethanolic phosphotungstic acid technique of Bloom and Aghajanian has been applied to formalin-fixed neuropathological specimens. The staining reactions of various normal organelles were studied as well as a number of pathological alterations including Alzheimer neurofibrillary tangles, eosinophilic rod-like structures, corpora amylacea, lamellar bodies and honeycomb-like structures in the axoplasm.
4 citations
01 Jan 1973
TL;DR: In this paper, a mouse skin, aorta, esophagus and colon staining was performed using PTA at different hydrogen ion concentrations and combined with glycogen and lysozyme, which were used as model systems for carbohydrates and proteins.
Abstract: Phosphotungstic acid was used at different hydrogen ion concentrations and combined with glycogen and lysozyme, which were used as model systems for carbohydrates and proteins, respectively. Furthermore, in order to correlate the chemical analysis with the selectivity of the “staining” reaction, ultrastructural studies were carried out using mouse skin, aorta, esophagus and colon. When the heteropolyacid was used at a pH around 1.0, and not above 1.8, there was no interaction with glycogen whereas an extremely high lysozyme binding ensued. At these levels of hydrogen ion concentration the selectivity of the staining was quite apparent. The rise in pH of the phosphotungstic acid solutions determined a loss of specificity in the staining reaction accompanied by a consistent glycogen uptake. This anomalous reaction was interpreted as the result of a decomposition of the metal into two altogether different chemical compounds: phospho1 l-tungstic acid and free tungstates. The latter, like the molybdates, are known to be excellent complexing agents with carbohydrates. Recent experiments carried out in the ultrastructural field to understand better the binding mechanism between phosphotungstic acid (PTA) and various organic substrates led investigators to propose two different interpretations. The first indicated that PTA at low pH values has a chemical affinity for highly polymerized carbohydrates (glycosaminoglycans and glycoproteins) and that its interaction with the sugar moieties is due to the formation of hydrogen bonds (3). The second interpretation, instead, sustains that the heteropolyacid shows
1 citations
01 Jan 1973
TL;DR: In this article, a method for the determination of vanadium and molybdenum in minerals that contain uranium was described, where the vanadium was first separated in the 6M hydrochloric acid decomposing solution from the moly bdenum, iron, and uranium by employment of the strongly basic anion exchanger Dowex 1-X8 by elution with 6M hydric acid and determined then in the evaporation residue of the eluate by means of a modified form of the phosphotungstic acid method.
Abstract: A method is described for the determination of vanadium and molybdenum in minerals that contain uranium After the acid or alkaline decomposition of the sample, the vanadium is first separated in the 6M hydrochloric acid decomposing solution from the molybdenum, iron, and uranium by employment of the strongly basic anion exchanger Dowex 1-X8 by elution with 6M hydrochloric acid and determined then in the evaporation residue of the eluate spectrophotometrically by means of a modified form of the phosphotungstic acid method Thereupon the molybdenum which was adsorbed on the anion exchanger is selectively eluted with a mixture of 90 vol% methanol and 10 vol% hydrochloric acid and after evaporation of the eluate is determined spectrophotometrically by the thiocyanate method The organic substances that originate in the exchange resln and are now present in the vanadium or molybdenum eluates, and which interfere in the spectrophotometric determinations of these elements, are decomposed oxidatively by means of aqua regia or concentrated nitric acid and thus rendered harmless The findings obtained from analysis of ten minerals containing uranium exhibit excellent agreement (auth)