Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Ninhydrin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 973 records · Page 54Linked to original sources
PubMed1992

Detection of glycyrrhetinic acid-like factors (GALFs) in human urine.

Patients with the syndrome of apparent mineralocorticoid excess and those who ingest licorice show markedly decreased 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD) and 5 beta-reductase activity; both are important for the deactivation of glucocorticoids and other steroid hormones. Glycyrrhetinic acid (GA), present as its glycoside in licorice, is a potent inhibitor of both 11 beta-OHSD and 5 beta-reductase and, as we have also shown, confers Na(+)-retaining properties on glucocorticoids and amplifies those of aldosterone and deoxycorticosterone. We report the results of our initial studies demonstrating the presence of naturally occurring substances, which inhibit both 5 beta-reductase and 11 beta-OHSD as does GA, in partially purified extracts of urine from normotensive men and nonpregnant and pregnant women. Since these substances exhibit GA-like activity, we have termed them GA-like factors (GALFs). This "inhibitory" material is heat stable and does not react with ninhydrin; the majority is not extractable with ethyl acetate and thus is not a "free" steroid. When further purified by high-performance liquid chromatography with a methanol/water gradient, the majority of these GALFs appeared in two regions of inhibitory activity. The chemical nature of this material is currently being investigated. These experiments indicate that normal human urine contains GALFs that may play a role in Na+ homeostasis and regulation of blood pressure.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1988

Why the assay of serum cystine by protein precipitation and chromatography should be abandoned.

The higher bias of serum cystine estimations by a HPLC method compared with those by ion exchange techniques is shown to be largely due to differences in the sample preparation procedures of the two techniques. The ion exchange methods utilised sulphosalicylic acid serum protein precipitation and post-column ninhydrin derivatisation of cystine, whilst the high pressure liquid chromatography technique employed automated dialysis for removal of proteins and pre-column ortho-phthalaldehyde derivatisation of cystine after its conversion to cysteine and then to S-carboxymethylcysteine. Examination of these procedures showed that whilst the high pressure liquid chromatographic method accurately estimates total serum cystine and cysteine, many factors affect the precision and accuracy of serum cystine estimations using the ion exchange techniques. In particular, serum protein precipitation techniques that are currently employed for the preparation of samples for cystine analysis by ion exchange chromatography should be abandoned.

Blood Proteins↗
PubMed1976

Tissue fixation with diimidoesters as an alternative to aldehydes. II. Cytochemical and biochemical studies of rat liver fixed with dimethylsuberimidate.

Rat liver fixed with dimethylsuberimidate (DMS) was studied to investigate the use of diimidoesters as dixatives for light and electron microscopic cytochemistry. Paraffin sections of liver fixed with DMS at pH 9.5 were weakly stained with the ninhydrin-Schiff procedure, indicating extensive reaction of NH3+ groups with the fixative. Nuclei were strongly strained by the Feulgen procedure, with no background [corrected] reaction. In contrast, glutaraldehyde fixation resulted in a significant background reaction in the cytoplasm and nuclei in controls for the Schiff-based stains. DMS-fixed liver stained intensely for glycogen with the Periodic acid-Schiff procedure, and biochemical analysis of glycogen retention and extractability indicated that DMS retained considerably more glycogen in sections than glutaraldehyde. DMS-fixed liver incubated for thiamine pyrophosphatase activity revealed reaction product in ER cisternae, Goli saccules and bile canaliculi. Peroxisomes were strongly reactive for catalase activity after incubation in diaminobenzidine medium, and reaction product of glucose-6-phosphatase activity was considerably greater following DMS fixation than after glutaraldehyde. Biochemical studies revealed up to twice as musch residual activity of glucose-6-phosphatase after DMS fixation. These results suggest that DMS may be useful as a primary fixative for certain cytochemical procedures.

Aldehydes↗
PubMed1978

The effect of aldehyde fixation on selected substrates for energy metabolism and amino acids in mouse brain.

The effect of aldehyde fixation on concentrations of low molecular weight constituents was determined by comparing amounts of selected intermediates in brains of mice exposed to aldehyde fixative solutions with those perfused with phosphate buffer solution alone. Aldehyde perfusion resulted in excellent preservation of cerebral cortex ultrastructure in the presence of dramatic declines in adenosine triphosphate, phosphocreatine, glucose and glucose-6-phosphate that occureed before exposure of the tissue to aldehyde fixatives. Decreases in hexose were accompanied by approximately a 4-fold increase in lactate and a 2-fold increase in pyruvate. Glycogen levels decreased by about 60% during the initial operative procedure but remained constant after aldehyde fixation. Glycogen content declined approximately 90% in tissues that were not treated with aldehyde. Concentrations of aspartate and glutamate changed only slightly during the initial period (1-5 min) and remained constant for at least 90 min in cerebral cortices fixed with aldehydes. Alanine levels increased in both fixed and unfixed tissue; however, this increase was much smaller in tissues exposed promptly to aldehydes. Total ninhydrin-positive material in perchloric acid extracts of brain decreased in mice exposed to aldehyde solutions but increased in tissues that were not. These results indicated that several amino acids may be measured reliably in tissues preserved for light and electron microscopy. In addition, determination of glutamate: alanine ratios in tissues perfused with aldehydes may provide an indication of the timing of fixation.

Aldehydes↗
PubMed1975

The chemical composition of idiopathic nonarteriosclerotic cerebral calcifications.

Calculi from a case of cerebral idiopathic nonarteriosclerotic calcification (Fahr's disease) were examined. The stone consists of hydroxyapatite and possesses a typical structure: the calcification process seems to be initiated by the formation of small round bodies that are cemented to each other to form the final stone. Calcified vessels are also present, but seem to be a secondary effect. From a comparison with other calcifications, it is concluded that no pathologic significance should be attached to the relatively high levels of trace metals such as zinc, iron, copper, magnesium, lead, and others, with the possible exception of manganese. The organic matrix of the stone contains large quantities of protein. On hydrolysis of this fraction, an important unidentified ninhydrin-positive peak was found. No mucopolysaccharides were found.

Activation Analysis↗
PubMed2003

Spectrophotometric determination of some drugs for osteoporosis.

Three simple, accurate and sensitive spectrophotometric methods are developed for the determination of some new drugs for the treatment of osteoporosis: risedronate sodium (I), alendronate sodium (II) and etidronate disodium (III). The first method is based on the measurement of difference in absorbance (Delta A) of risedronate sodium in 0.01 mol l(-1) hydrochloric and 0.1 mol l(-1) sodium hydroxide at 262 nm. Beer's law is obeyed over a concentration range of 15-150 microg ml(-1) with mean recovery 99.75+/-1.22 and molar absorptivity (epsilon) 1.891 x 10(3). The second method is based on the reaction of the primary amino group of (II) with ninhydrin reagent in methanolic medium in the presence of 0.05 mol l(-1) sodium bicarbonate. The colored product is measured at 568 nm, and the linearity range is found to be 3.75-45 microg ml(-1) with mean recovery 99.77+/-0.73 and epsilon 9.425 x 10(3). The third method is based on oxidation of the three mentioned drugs with ceric (IV) sulphate in 0.5 mol l(-1) sulphuric acid at room temperature and subsequent measurement of the excess unreacted cerium (IV) sulphate at 320 nm. The method obeyed Beer's law over a concentration range of 2-24 microg ml(-1) for the three drugs with mean recovery 99.79+/-1.16, 99.73+/-1.38 and 99.86+/-1.13 and epsilon 14.427 x 10(3), 13.813 x 10(3) and 14.000 x 10(3) for drugs I, II, III respectively. The proposed methods were successfully applied for the determination of the studied drugs in bulk powder and in pharmaceutical formulations. The results were found to agree statistically with those obtained the reported methods. Furthermore, the methods were validated according to USP regulations and also assessed by applying the standard addition technique.

Alendronate↗
PubMed1998

[Highly effective separation and highly sensitive detection for clinical chemistry and biochemistry].

Highly effective separation and highly sensitive detection reagents for clinical chemistry and biochemistry were developed and their applications were investigated. The sensitive detection of carboxylic acids was accomplished using 9-anthryldiazomethane (ADAM) which gave intensely fluorescent derivatives from carboxylic acids without catalysts or heating. 1-Pyrenyldiazomethane was then synthesized and proved to react also readily with carboxylic acid and more sensitive than ADAM. The optical resolution of amino acid enantiomers was achieved using 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate (GITC). GITC derivatized enantiomeric amino acids under mild conditions to give highly hydrophobic diastereomers which could be resolved on conventional reversed phase columns and easily detected by the absorption based on the thiourea structure. Then we devised an o-phthalaldehyde-N-acetylcystein reagent (OPA/NAcCys) giving diastereomers which were also resolved on a reversed phase column and detected fluorometrically with excellent sensitivity. OPA/NAcCys was useful for the assay of D-amino acids in the blood of uremic patients. The hypochlorite-thiamine method for the assay of proteins and peptides was established providing sensitive fluorometry, which well reflected the number of peptide groups in the molecule. This principle was applied to the assay using N-chlorodansylamide, designed for the fluorometry of peptides. The alkaline ninhydrin method was applied to the detection of guanidino compounds in the blood of uremic patients. Several fluorometric methods for the simultaneous detection of reducing and non-reducing carbohydrates, and guanidines were found to be useful reagents for this purpose because these compounds were resistant to the oxidation with periodate. Then protamine-bound columns were prepared for the separation of carbohydrates on HPLC, which showed excellent recovery of reducing carbohydrates in comparison with conventional alkylamino columns.

Amino Acids↗
PubMed2006

Reference data for cerebrospinal fluid and the utility of amino acid measurement for the diagnosis of inborn errors of metabolism.

BACKGROUND: Cerebrospinal fluid (CSF) amino acid analysis is fundamental to the investigation of several inherited metabolic diseases, particularly those presenting with unexplained seizures. CSF glycine measurement is often crucial to the diagnosis of glycine encephalopathy (GE), low CSF serine concentrations are characteristic of 3-phosphoglycerate dehydrogenase deficiency (3-PGDD) and the presence of sulphocysteine is pathognomonic of sulphite oxidase deficiency (SOD), and a vital clue to molybdenum cofactor deficiency (MCD). Limited information is available in the literature on reference values of amino acids in CSF during infancy and CSF samples from healthy individuals are not easily obtained. METHODS: In order to establish paediatric CSF amino acid reference ranges, we performed a retrospective analysis of all quantitative CSF amino acid data collected in our laboratory over a five-year period. Amino acid analysis was performed using ion-exchange chromatography on a Biochrom-20 amino acid analyser with ninhydrin detection. CSF samples were collected from infants undergoing investigation for unexplained seizures. RESULTS: About 18 of the 95 samples received were excluded from the reference data-set; one was from a patient in whom a diagnosis of GE was confirmed by enzyme analysis, one was from a patient with CSF sulphocysteine of 19 micromol/L in whom a diagnosis of SOD was confirmed by enzyme analysis; the remaining 16 were clearly bloodstained (n = 4) or xanthochromic (n = 12). Frequency of distribution analysis revealed that concentration values for each amino acid demonstrated a right-skewed distribution which was not normalized by log transformation. Data were therefore analysed using non-parametric descriptive statistics and reference ranges were defined by the 2.5th and 97.5th centile limits. CONCLUSIONS: Our reference data were derived from 77 CSF samples taken from 77 infants. Median CSF glycine concentration was 9 micromol/L with a reference range of 3-19 micromol/L. For serine, the median CSF concentration was 52 micromol/L with a reference range of 25-105 micromol/L. Sulphocysteine was not normally present in detectable quantities (<1 micromol/L).

Amino Acid Metabolism, Inborn Errors↗
PubMed2003

Neonatal birth parameters of positive newborns at PKU screening as predictors of false-positive and positive results at recall-testing.

OBJECTIVES: To investigate the predictive role that neonatal birth parameters of positive newborns at phenylketonuria (PKU) screening have on false-positive and positive results. We reviewed 195 newborns (115 males and 80 females) that had false-positive results between 1998 and 2001. A total of 4386 randomly selected neonates (2191 males and 2195 females) who tested normal at the first investigation in the same period, were used as negative-controls. A total of 38 PKU neonates (17 males and 21 females) diagnosed between 1990 and 2001 were used as positive-controls. METHODS: Phenylalanine concentration was measured with a fluorometric multitask plate counter Wallac 1420 VICTOR F (Perkin Elmer, Finland) and the fluorescent ninhydrine method (EG&G Wallac neonatal phenylalanine kit) using a recall cut-off level >120 micromol/l (2 mg/dl) of phenylalanine on dried blood spots. A multivariate logistic regression analysis was performed to evaluate the predictive role that body parameters (sex, gestational age, parity, weight, length and head circumference) of positive newborns at PKU screening had on false-positive and positive results at recall PKU tests. RESULTS: The risk of false-positive results is higher (~48%) in females than in males. Moreover, for each 100g of body weight reduction, the risk of false positive is around 4.2% higher. The risk of confirmation increased by 39% per week of gestational age. CONCLUSIONS: In conclusion, our results suggest that preterm or low-birth-weight neonates recalled at the first investigation are more likely to be due to false-positives, whereas the risk of confirmation is higher in at-term neonates. By implication, the phenylalanine cut-off value for premature or low-body-weight infants could be higher.

False Positive Reactions↗
PubMed2002

Accumulation of L-cystathionine by an Escherichia coli mutant deficient in cystathionine beta-lyase.

An Escherichia coli mutant deficient in cystathionine beta-lyase was found to accumulate a substance detectable by ninhydrin reaction and chloride platinic acid reaction in its cells (rarely in the culture supernatant) when cultured with a limited amount (50-200 microg/ml) of L-methionine to support the growth. The product was released by freezing treatment and isolated by ion-exchange chromatography (cation exchange resin: Daiaion SK1B). It was identified as L-cystathionine by liquid chromatography-mass spectrometry, 13C- and 1H-nuclear magnetic resonance analyses and high-performance liquid chromatography (as its 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate derivative).

Journal Article↗
PubMed1976

Free amino acids in the caput and the cauda epididymis of adult rats.

To examine the content and the composition of free amino acids in the intraluminal fluid of rat epididymis, the fluids were obtained by light pressure on the dissected tissues. The amount of the total free amino acids in the pressed fluid from the caput epididymis was significantly higher than those of the cauda epididymis and the testis. Glu and Gln were predominant amino acids in the caput, and their amounts occupied more than half of the total ninhydrin reactive compounds. Such a high concentration of Glu and Gln was not observed either in the cauda or in the testis. Castration decreased Glu and increased Gln in amount. Testosterone treatment to castrated animals did not restore Glu and Gln contents in the pressed fluid from the caput epididymis to the level observed in intact rats completely. Therefore, it was assumed that a large amount of Glu in the caput was due to many factors; secretion and metabolism of epithelial cells of the gland which might be regulated by androgen, inflow of rete testis fluid, and sperm metabolism of amino acids in the epididymis. The results obtained from the caput epididymis to which the efferent duct of the testis was ligated also supported this interpretation.

Amino Acids↗
PubMed1976

The sequence determination of a protein in a micro scale: the sequence analysis of ribosomal protein L34 of Escherichia coli.

The complete amino acid sequence of ribosomal protein L34 has been established by improved micro techniques with 3 mg of the lyophilized protein. The protein was digested with trypsin, thermolysin and chymotrypsin and the resulting peptides were isolated from fingerprints performed on cellulose thin-layer plates. The amino acid sequences of the peptides were determined by the combined micro dansyl-Edman technique using 5 - 10 nmol per sample. Aspartic acid and glutamic acid were distinguished from their amides by use of the color reaction of ninhydrin with the respective amino acid phenylthiohydantoins.

Amino Acid Sequence↗
PubMed1978

Purification and properties of 3-cis-2-trans-enoyl-CoA isomerase (dodecenoyl-CoA delta-isomerase) from rat liver mitochondria.

The mitochondrial enzyme 3-cis-2-trans-enoyl-CoA isomerase, responsible for the positional and geometric isomerization of beta,gamma-unsaturated fatty acyl-CoA intermediates arising during beta-oxidation of unsaturated long chain fatty acids, has been isolated from rat liver, purified to homogeneity by a heat step and a combination of gel filtration and ion-exchange chromatographic procedures. The enzyme has a molecular weight of 30,000, as determined by dodecylsulfate polyacrylamide gel electrophoresis. The isomerase has a strong tendency to form a dimer. It elutes from a calibrated Sephadex G-200 column with an apparent Mr = 60000. The basic isoelectric point, pI 9.0-9.2, is due to its high content in basic amino acids. The amino acid composition determined by the ninhydrin and o-phthalaldehyde detection method is presented.

Acyl Coenzyme A↗
PubMed1988

A rapid and sensitive microassay for bacterial collagenase and other proteolytic activities on collagenous substrates.

Many of the common substrate digestion assays have the disadvantage of being tedious and expensive, thus aggravating serial determinations of collagenase activity. In the assay presented here, the proteolytic reaction proceeds on a sheet of chromatographic paper bearing spots of dried gelatin or collagen solutions. After application of the enzyme sample, the sheets are incubated in a water-saturated atmosphere for 45 min and the reaction products are visualized by spraying with chromatographic, ninhydrin-containing peptide reagents. By its specific yellow staining, the activity of bacterial collagenase can be discriminated from the gray, brown, red, or violet spots which are produced by eight tested noncollagenolytic proteases. The detection limit for collagenase activity reaches down to 0.002 U in a sample volume of 1-2 microliters dropped onto a spot of 25 microliters gelatin solution (3%), thus corresponding with the sensitivity of a conventional radioassay. The sensitivity for noncollagenolytic proteases is better than 2 ng per sample, herewith exceeding a common casein-agar diffusion test. The method is also evaluated for native collagen. Within 1.5 h, 100 samples can be assayed. An example for the application in a collagenase purification step (ion exchange chromatography) is also presented.

Bacteria↗
PubMed2005

Multiple positive results during a neonatal screening program: a retrospective analysis of incidence, clinical implications and outcomes.

AIMS: Neonatal screening programs perform different screening tests on the same blood-spot sample collected on a Guthrie card. We retrospectively investigated the incidence of multiple positive results as well as the outcomes and the physical characteristics of newborns with more than one positive result for phenylketonuria (PKU), congenital hypothyroidism (CH) and congenital adrenal hyperplasia (CAH). METHODS: Neonatal screening was performed on blood-spot for PKU (phenylalanine concentration by fluorescent ninhydrine method), for CH (simultaneous total thyroxin (tT4) and thyroid-stimulating hormone (TSH) levels by fluoroimmunometric assay); and for CAH (17-hydroxyprogesteron level by fluoroimmunometric assay). RESULTS: During three years of screening, 39 newborns (37 preterms) showed multiple positive results at screening tests (incidence 1:6387). The most frequent positive results were the combinations of CH and CAH (25/39) and PKU and CH (12/39). At recall, only two newborns were confirmed positive and each for only one disease: one, premature baby, for PKU from the PKU and CH combination; the other, born at term, for CAH from the CH and CAH combination. CONCLUSIONS: Multiple positive results are a rare observation at neonatal screening for PKU, CH and CAH, more frequently observed in preterm babies. However, multiple positive results must not be overlooked because of true positive results at recall.

Adrenal Hyperplasia, Congenital↗
PubMedDate not supplied

A biochemical approach for detecting interactions between peptides from the HIV gp120 glycoprotein and a CD4 sequence.

Peptides selected from the HIV viral protein gp120 bind to a synthetic peptide mimicking sequence 78-89 of the human lymphocyte CD4 molecule, linked to activated Sepharose. The binding of viral fragments to the CD4 peptide-Sepharose beads was ascertained either by aid of a ninhydrin reagent or by fluorescence microscopy. A suitable alignment of these HIV peptides with the CD4 fragment showed that multiple interactions might occur between hydrophobic or charged groups of the two molecules. Although this experiment does not demonstrate that these two amino acid stretches are involved in the primary binding of gp120 to CD4 receptors, the present data suggest that the two sequences might have some kind of interaction during subsequent steps of viral infection.

Amino Acid Sequence↗
PubMed1975

Developmental changes of free amino acids in bovine fetal fluids with gestational age and the interrelationships between the amino acid concentrations in the fluid compartments.

Thirty ninhydrin-positive compounds were determined in the sera, amniotic fluid, stomach content and allantoic fluid from 29 bovine fetuses of various gestational ages. Fetal serum was found to contain about 3-fold higher concentrations of free amino acids (FAA) than maternal serum, and allantoic fluid contained about 3-fold higher concentration of FAA than fetal serum. Decreasing concentrations of FAA were found in serum as a function of the crown-rump length for the amino acids taurine, aspartic acid, threonine, serine, ornithine and lysine. Decreasing concentrations of FAA in allantoic fluid were found for threonine, alanine and ornithine, whereas increasing concentrations were found for phosphoserine and methionine as a function of the crown-rump length. Correlations were found between the concentrations of most amino acids in amniotic fluid and stomach content, but fewer correlations were found between the other fluid compartments. The transport of amino acids between compartments is discussed.

Alanine↗
PubMed1981

Chemical and biological properties of subfractions of hot-water extract from delipidated BCG.

a hog-water extract from delipidated Mycobacterium bovis strains BCG was fractionated by precipitation with ethanol. The chemical and biological properties of the subfractions thus obtained were investigated. A subfraction precipitated at 20% ethanol contained less neutral sugar and more ninhydrin-positive substance than other subfractions. Only the guinea pigs that were treated with 20% ethanol-precipitate showed no humoral antibody response to egg white albumin, despite positive skin reaction. The subfractions precipitated at low concentrations of ethanol exhibited a significant antitumor activity in ddY and C3H He mice inoculated intraperitoneally with tumor cells. These results suggest that the hot-water extract from delipidated BCG consists of subfractions with different chemical and biological properties.

Adjuvants, Immunologic↗