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PubMed1989

Phospholipid and fatty acid composition of erythrocytes in type I and type II diabetes.

Different data have been reported concerning modifications of the erythrocyte lipid composition in the different types of diabetes. The heterogeneity of diabetes could be a cause for such differences. Ten type I and ten type II diabetics were carefully selected. The patients were poorly controlled (the mean glycosylated hemoglobin was 12.8% +/- 0.7%); their mean age was 54 +/- 5 years, with a mean duration of diabetes of 18 +/- 4 years. One half of them had severe diabetic complications (nephropathy, retinopathy, and/or polyneuropathy). The diabetics were compared with ten controls. The phospholipid composition was determined by HPTLC analysis, and the fatty acid moieties of the total phospholipids were measured by gas liquid chromatography associated with mass spectrometry. Under well-defined experimental conditions, these results demonstrated a slight, but significant (P less than .05), increase in the phosphatidylethanolamine (PE)/phosphatidylserine (PS) ratio using a Ninhydrin quantitation method; there was also an increase in two minor lipids content (phosphatidylinositol, phosphatidic acid) and the appearance of a lysolipid (lysoPE) in the patients. Whatever the type of diabetes, the red blood cells of diabetics showed no significant differences in their fatty acid contents.

Adolescent↗
PubMed1992

Guanidino compounds in serum, urine, liver, kidney, and brain of man and some ureotelic animals.

Guanidino compound levels were quantitatively determined in serum, urine, liver, kidney, and brain of man and of some ureotelic animals. The guanidino compounds were separated over a cation exchange resin, using sodium citrate buffers, and detected with the fluorescence ninhydrin method. Species-specific differences in the levels of some guanidino compounds in the studied ureotelic animals are shown. alpha-Keto-delta-guanidinovaleric acid is a naturally occurring guanidino compound in ureotelic animals, and is not restricted to the pathobiochemistry of hyperargininemic patients. The fasting serum levels observed in beagles are the same as those found in hyperargininemic patients. In serum, liver, and kidney, the homoarginine, beta-guanidinopropionic acid, and gamma-guanidinobutyric acid levels are the highest in rats. The last two compounds have the highest levels of the studied guanidino compounds, with the exception of creatinine, in kidney. Specific high levels of gamma-guanidinobutyric acid and argininic acid are found in brain of rabbits.

Animals↗
PubMed1983

Separation and partial characterization of smooth muscle contractile material in the venom of the scorpion Heterometrus bengalensis.

A smooth muscle contractile material was separated from crude venom of the scorpion Heterometrus bengalensis (found in Eastern India) by solvent extraction, gel filtration and thin layer chromatography. Smooth muscle contractile material could be extracted, in descending order of efficiency, with methanol, butanol, ethanol and acetone. The contractile material separated by gel filtration (Sephadex G-25) when further extracted, using the Folch procedure, showed a single spot in thin layer chromatography with one solvent system. Rechromatography of an eluate from this spot with another solvent system resolved it into three spots (SL1, SL2 and SL3, the mixture being designated as Substance L) which could be visualized either with iodine vapour, ninhydrin or molybdenum reagent. Eluates from the three spots contracted guinea-pig ileum which had been pretreated with antagonists of ACh, histamine, 5-HT and prostaglandins. Substance L and its fractions (SL1, SL2 and SL3) contain inorganic phosphorus, amino nitrogen and amino sugar, which point to the likelihood of their being glycophosphatides.

Animals↗
PubMed1988

Properties of two toxins isolated from the blue-green alga Microcystis aeruginosa.

Attempts were made to characterize the two toxins (P-1 and P-2) isolated from the blue-green alga Microcystis aeruginosa, by amino acid analysis, mass spectrometry, 1H- and 13C-NMR. P-2, the major toxin, had a molecular weight of 1044, and consisted of one molecule each of beta-methylaspartic acid, D-Glu, D-Ala, L-Arg, L-Tyr, N-methyldehydroalanine, and 3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid (Adda). P-1, with a molecular weight of 994, appeared to have almost the same composition except that it contained L-Leu instead of L-Tyr in P-2. Mass spectrometric studies, along with a negative ninhydrin reaction, indicated that each toxin was a cyclic peptide. P-2 showed an LD99 of 70 micrograms/kg mice when injected i.p. and [alpha]D24 of -72.42 degrees (c = 0.095 in methanol), and was decomposed at around 218 degrees C.

Amino Acids↗
PubMed1986

Molecular mechanisms of cataractogenesis: IV. Evidence of phospholipid . malondialdehyde adduct in human senile cataract.

Lipid extracts of the human cataractous and normal lenses were analyzed by thin-layer chromatography (TLC) using a solvent system consisting of CHCl3/CH3OH/CH3COOH/H2O (50:25:7:3 by vol.). A novel phospholipid having a Rf intermediate between phosphatidyl ethanolamine (PE) and phosphatidyl serine (PS) was detected besides the four major phospholipids viz., PE, PS, phosphatidyl choline (PC) and sphingomyelin (SP). The novel phospholipid was found to be molybdenum positive and ninhydrin negative having a characteristic fluorescence of Schiff-base conjugate formed between PE, malondialdehyde (MDA) and PS. It was possible to resolve this adduct into PE and PS after acid hydrolysis using two dimensional TLC with CHCl3/CH3OH/NH3 (7 M) (65:25:4 by vol.) as the second solvent. In cataract PE . MDA . PS adduct increased significantly as did diene conjugates and MDA. In plasma membrane lipid extract of cataractous lenses there was a marked increase in fluorescence at 460 nm when excited at 365 nm showing a characteristic fluorescence of a typical Schiff-base conjugate. The evidence suggests that peroxidation of lenticular plasma membrane lipids is one of the molecular mechanisms involved in cataract in the human.

Cataract↗
PubMed1976

Transfer factor: hypoxanthine is a major component of a fraction with in vivo activity.

Transfer factor was prepared from the leukocyte lysates of four donors with known skin test reactivity. After ultrafiltration and double-gel filtration on polyacrylamide gels, fraction IV of the preparation was found to have biologic activity. This fraction contained one major and occasionally one minor ultraviolet-absorbing and zero to one ninhydrin-detectable spots on thin-layer chromatography. The major ultraviolet spot was identified as hypoxanthine. Hypoxanthine was demonstrated to be responsible for the high 260 nm/280 nm ratio of preparations with biologic activity in vivo. It was not determined if hypoxanthine is required for transfer factor activity. In addition, an orcinol-negative preparation also had biologic activity.

Chromatography, Thin Layer↗
PubMed1980

Comparison of the venom immunogenicity of various species of yellow jackets (genus Vespula).

Venoms from various yellow jacket species were examined by two-dimensional thin-layer chromatography (TDTLC), double-diffusion gel precipitation (DDGP) using rabbit antisera, and the radioallergosorbent test (RAST). Comparison of representative venoms by the TDTLC showed that the venoms of V. vulgaris and V. maculifrons have a larger number of Ninhydrin (triketohydrindene hydrate)-positive substances than the venom of V. squamosa. The results of the DDGP confirmed the differences; venoms of V. vulgaris, V. maculifrons, V. flavopilosa, and V. germanica have one or more major components with immunogenic identity. The venom of V. squamosa has a species-specific major component and some minor components immunologically identical to the other venoms examined. Sera from 21 patients with a history of anaphylaxis following yellow jacket stings were examined by the RAST. Using the venoms of V. maculifrons, V. vulgaris, V. flavopilosa, and V. germanica as coupling antigens, most sera reacted similarly. The sera did not react with V. squamosa. These results suggest that the major component in venom obtained from the four yellow jacket species has immunogenic identity. Venom of V. squamosa differs from the remaining venoms. As a practical corollary, with the exception of venom from V. squamosa, common sensitivity appears to exist among the yellow jacket venoms examined.

Animals↗
PubMed1994

Extractable latex allergens and proteins in disposable medical gloves and other rubber products.

BACKGROUND: IgE-mediated sensitization to rubber proteins is being reported with increasing frequency in health care workers. To explore the relative importance of various sources of allergen exposure, we measured the total rubber allergen and protein levels in extracts of disposable rubber gloves and compared the allergen levels with those in extracts of other medical and consumer rubber products. METHODS: Rubber allergens were measured by inhibition immunoassay with a rubber glove extract as the solid-phase allergen and pooled plasma from five rubber-sensitized health care workers as the IgE antibody source. Proteins were measured by Ninhydrin assay. RESULTS: Among 71 lots of gloves tested, the extractable allergen and protein levels were significantly correlated and were appreciably higher in powdered gloves than in powder-free gloves. Allergen levels varied 3000-fold among gloves from different manufacturers and were higher in examination gloves than in surgical or chemotherapy gloves. Measurable allergen was found in 11 of 24 lots of "hypoallergenic" gloves tested. Allergen levels in toy balloons were comparable to those in powdered gloves; much lower allergen levels were measured in condoms and anesthesia rebreathing bags. CONCLUSIONS: The allergen content of disposable rubber gloves varies widely and is higher in powdered gloves than in powder-free gloves and higher in examination gloves than in surgical gloves. Hypoallergenic gloves may contain substantial amounts of IgE-binding proteins. Gloves and toy balloons appear to be more important sources of rubber allergens than the other rubber products tested.

Allergens↗
PubMed1986

Immobilization of collagen onto polymer surfaces having hydroxyl groups.

The cyanogen bromide (CNBr) activation method was adopted to link collagen molecules onto the surface of cellulose and poly(vinyl alcohol) (PVA) films via covalent bonding. The amount of bound protein was determined by the ninhydrin method and found to be 1.0 microgram/cm2 for the native collagen and 0.6 microgram/cm2 for the denatured collagen. The amount of bound protein was larger for cellulose than PVA. When p-toluene-sulphonyl chloride was used to activate the cellulose film, this activation method was found to be effective in grafting the collagen as well. The cellulose film was found to become brittle and weak after activation with CNBr, but the PVA films was not. This might be due to the difference in the extent of crosslinking between cellulose and PVA films, as demonstrated by the change in degree of swelling and solubility of both the activated films.

Biocompatible Materials↗
PubMed1993

Identification of alpha-carboxamidated and carboxy-terminal glycine forms of peptides in bovine hypothalamus, bovine pituitary and porcine heart extracts.

Two chemical assays have been developed for identifying and quantifying peptides which either could be biologically active by virtue of their alpha-carboxamidation or could be substrates for peptidylglycine alpha-amidating mono-oxygenase. The first assay is specific for the alpha-carboxamide of peptides. Using bis[trifluoroacetoxy]iodobenzene, the alpha-carboxamide was converted via a Hoffman reaction into a primary amine, which was then quantified by ninhydrin. The second assay is specific for glycine at the carboxy-terminus of a peptide. Glycine at the carboxy-terminus was derivatized to form 2-thiohydantoin, which was then separated and quantified by reverse phase HPLC. These assays were used to detect peptides in HPLC-separated extracts of bovine hypothalamus, bovine anterior lobe pituitary and porcine heart which may be of biological interest.

Acetylation↗
PubMed1984

Acute effect of mercury toxicity on some enzymes in liver of teleost Sarotherodon mossambicus.

The effects of 1.5 ppm of mercuric chloride (LC50/48 hr) on some enzymes and organic substances of liver tissue of Sarotherodon mossambicus were studied. Significant decreases in the activities of succinate dehydrogenases, lactate dehydrogenases, glucose-6-phosphate dehydrogenase, alkaline phosphatase, and acid phosphatase and in the levels of organic substances like total anthrone-positive substances, glycogen, and total ninhydrin-positive substances were observed. The results indicate impaired oxidative and transphosphorylative activities and utilization of carbohydrates during acute mercury toxicosis in fish.

Animals↗
PubMed1979

Isoelectric focusing of oligopeptides: detection by specific stains.

By using ultrathin (350 micrometers) polyacrylamide gels, which at the end of the fractionation are pasted to filter paper and dried in an oven at 110 degrees C, and after isoelectric focusing it has been possible to detect oligopeptides in the di- to tetradecapeptide range, which could not be detected by protein staining techniques. This is achieved by developing a series of specific stains for the following amino acids: Arg, Tyr, His, Trp, Met and Cys. Except for Met and Cys, the detection limits appear to be in the order of 0.2--2 micrograms of free amino acid loaded in the gel. The Pauli reaction for His and Tyr and the Sakaguchi stain for Arg can be developed sequentially in the same gel, thus allowing the detection of four different amino acids since, under these conditions, also Trp reacts. Unfortunately, more general reactions, such as the permanganate, the 'Lowry' and the ninhydrin stains, cannot be utilized since the carrier ampholytes react very strongly with all these reagents.

Amino Acids↗
PubMed1982

Micro-analysis of amino acids.

An automated amino acid analyzer has been developed for the analysis of amino acids with the sensitivity at the 10-100 pmol level except for proline which requires greater than 50 pmol. omicron-Phthalaldehyde, in the presence of 2-mercaptoethanol, is used for the fluorometric detection of amino groups (Roth, M. (1971) Anal. Chem. 43, 880-882). A post-column reaction of the amino acid with sodium hypochlorite (Bohlen, P. and Mellet, M. (1979) Anal. Biochem. 94, 313-321) gives oxidation products amenable to detection with omicron-phthalaldehyde. The instrument uses high-performance liquid chromatographic pumps capable of micro-flow rates with a minimum pulsation. The method is suitable for routine analyses of amino acids at picomole levels with reproducibility and accuracy comparable to the ninhydrin-based amino acid analysis.

Amino Acids↗
PubMed1983

Analytical and preparative isoelectric focusing of peptides in immobilized pH gradients.

A new method for peptide analysis and purification is described, based on isoelectric focusing in immobilized pH gradients. On the analytical scale, the peptide zones can now be revealed by any stain for primary and secondary amino groups (e.g. ninhydrin, fluorescamine, dansyl chloride) since the buffering species, unlike conventional carrier ampholytes, contain only carboxyl and tertiary amino groups. For preparative purposes, conditions have been described to remove most contaminants (e.g. unreacted monomers, non-cross-linked, short polyacrylamide chains) from the gel matrix before the electrophoretic run. However, ca. 2% of the gel dry mass is still present as extractable material. The focused peptides can be recovered in high yields (ca. 90%) with a fairly high degree of purity (75%), the contaminants being mostly components eluted from the polyacrylamide gel.

Chromatography, Thin Layer↗
PubMed1990

Amino acid measurement by high-performance liquid chromatography using electrochemical detection.

The measurement of amino acids by high-performance liquid chromatography has become more common in recent years. Separation can be by gradient elution of the native amino acids followed by reaction with ninhydrin or by pre-column derivatisation with ultraviolet or fluorescent detection. The use of electrochemical detection for the measurement of amino acid derivatives formed with either o-phthalaldehyde or phenylisothiocyanate is discussed. A method for the assay of amino acids in human blood serum and urine samples using phenylisothiocyanate as the derivatizing agent and electrochemical detection is described and compared to previously reported methods based on o-phthalaldehyde derivatisation.

Amino Acids↗
PubMed1985

Activation of sodium cyanide to a toxic but non-mutagenic metabolite in Salmonella typhimurium.

Salmonella typhimurium strains (OASS-positive) synthesize a toxic but non-mutagenic metabolite from cyanide and O-acetylserine. Salmonella typhimurium mutant DW379 (OASS-deficient) is neither able to carry out this reaction in vitro nor produce the toxic metabolite in vivo. L-Cysteine reverses the cyanide metabolite mediated inhibition and thus allows OASS-positive strains to grow in medium containing cyanide and O-acetylserine. The results suggest that the enzyme O-acetylserine sulfhydrylase catalyzes the reaction of cyanide and O-acetylserine to form the toxic metabolite. This metabolite is ninhydrin-positive, adheres strongly to the cation-exchange column, and migrates in TLC to an Rf value similar to that of beta-cyanoalanine.

Biotransformation↗
PubMed1992

Efflux and accumulation of amino nitrogen in relation to the volume of rat renal inner medullary cells exposed to media of variable osmolality.

The rate of efflux of 2-amino[14C]isobutyric acid (AIB) from pre-loaded slices of rat renal inner medulla has been followed during incubation in media whose osmolality was varied between 350 and 2500 mosmol/kg H2O by adjustment of NaCl and urea concentrations. Efflux was biphasic, and it was assumed that the second, slower phase represented mainly cellular loss of AIB. As a function of cell volume (water content) the mean net rate of 2nd phase efflux declined far more abruptly (-36%) during an increase in external osmolality from 350 to 720 mosmol/kg than during further increase to 2500 mosmol/kg, over which range the rate of efflux fell by only a further 12%. Conversely, relative decrements of steady-state cell water contents during these two transitions were -17% and -37%, respectively. It is probable that in strongly hyperosmolal media (above 720 mosmol/kg) reduction in the rate of amino acid catabolism, with resultant cellular accumulation, becomes more important than passive efflux as a determinant of cell amino nitrogen content, and that this is caused by the enzyme-destabilizing effect of high intracellular concentrations of permeant urea. This interpretation is supported by the finding in the present study that trimethylamine N-oxide, which is known to counteract the destabilizing effect of urea, completely inhibited the accumulation of amino nitrogen (ninhydrin-positive substances) in media stronger than 720 mosmol/kg, as well as leading to further reduction of steady-state cell water contents, but was without effect on either variable in more dilute media. It is proposed that, under the conditions of this investigation, amino acids contribute to cell volume maintenance mainly by efflux and by metabolic accumulation under mildly and strongly hyperosmolal conditions, respectively, and that this interpretation is consistent with recent findings on the fluctuations in medullary levels of Na+, urea and total amino nitrogen in the intact kidneys of rats during acute water diuresis and oliguria (Law, R.O. (1991) Pflügers Arch. 418, 442-446).

Amines↗
PubMedDate not supplied

Characterization of synaptosomal membrane Na+, K(+)-ATPase inhibitors.

Previous work carried out in this laboratory has led to the isolation from rat brain of an aqueous soluble fraction (peak II) inhibiting synaptosomal membrane Na+, K(+)-ATPase and possessing other ouabain-like properties. Brain peak II was subjected to several treatments or fractionation by reversed-phase or anionic exchange HPLC and the effect of resultant fractions tested on synaptosomal membrane ATPase activity. The inhibitory components proved highly hydrophilic since they were neither extracted by hexane nor retained by a C-18 HPLC column, ruling out a lipidic nature. By anionic exchange chromatography, peak II was separated into eight fractions, two of which, named II-A and II-E, presented inhibitory activity, had low molecular weight, reacted with ninhydrin and were sensitive to acid hydrolysis. Fraction II-A was further chromatographed through a C-18 column, rendering five fractions, II-A1 to II-A5, inhibitory activity being confined to the most hydrophilic one (II-A1). Fraction II-E seems non-peptidic in nature, and its inhibitory activity was completed lost by alkalinization. II-E differs from authentic ouabain in u.v. spectrum, chromatographic behaviour and alkali sensitivity. It is suggested that two small hydrophilic compounds, probably one peptidic (II-A1) and another non-peptidic (II-E) in nature are involved in the regulation of Na+, K(+)-ATPase activity at the synaptic membranes.

4-Nitrophenylphosphatase↗