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PubMed2002

Capillary electrophoresis for the determination of new markers of natural latex quality.

Nowadays, increasing use of latex products in the healthcare area has also led to an increase in new scientific controls of raw material and manufactured products in order to maintain higher standards in quality control. Since field latex is a rich environment for microbial growth, in the absence of adequate preservation, the carbohydrates that it contains become microbiologically oxidised to the so-called volatile fatty acids (VFAs). Samples of natural rubber latex coming from different countries and processed in different ways have been tested by applying a capillary electrophoresis method for the measurement of the short-chain organic acids present in sera. The separation was performed with phosphate buffer at pH 6.25 and cetyltrimethylammonium bromide (CTAB) as background electrolyte in an uncoated fused-silica capillary with -10 kV of applied potential. The sample needs no other pre-treatment more than coagulation to obtain the serum. In the assayed samples, it has been shown that poorly-preserved latex presented higher amounts of succinic acid and lower amounts of malic acid. The succinic to malic acid ratio may be an important parameter because it cannot be altered by dilution or similar processes such as the traditional VFA index, used to determine the quality of latex. Ratios for succinic to malic acid <0.6 have been found for well-preserved latex and >0.6 for poorly-preserved latex.

Electrophoresis, Capillary↗
PubMed1990

Effect of chemical modification of lysine amino groups on redox and protonmotive activity of bovine heart cytochrome c oxidase reconstituted in phospholipid membranes.

A study is presented of the effect of chemical modification of lysine amino groups on the redox and protonmotive activity of bovine heart cytochrome c oxidase. Treatment of soluble oxidase with succinic acid anhydride resulted in succinylation of lysines in all the subunits of the enzyme. The consequent change of surface charges from positive to negative resulted in inversion of the orientation of the reconstituted enzyme from right-side-out to inside-out. Reconstitution of the oxidase in phospholipid vesicles prevented succinylation of subunits III and Vb and depressed that of other subunits with the exception of subunits II and IV which were predominantly labeled in a concentration-dependent manner by succinic acid anhydride. This modification of lysines produced a decoupling effect on redox-linked proton ejection, which was associated with a decrease of the respiratory control exerted by the delta pH component of PMF. The decoupling effect was directly shown to be exerted at the level of the pH-dependent rate-limiting step in intramolecular electron flow located on the oxygen side of heme a.

Animals↗
PubMed2001

Monotherapy extracorporeal shock wave lithotripsy for the treatment of staghorn calculi in children.

PURPOSE: We evaluate the efficacy and parenchymal consequences of extracorporeal shock wave lithotripsy (ESWL) for staghorn calculi in children. MATERIALS AND METHODS: From 1991 to 1999, 16 young patients 5.5 months to 2 years old and 7 older children 6 to 11 years old were treated for complete (6) or partial (17) staghorn calculi. Infection was the main factor of lithogenesis, particularly in younger children. In 21 patients the stone burden was more than 20 mm. All patients were treated under general anesthesia using a 14 kV. Sonolith 3000 (14) or a 12 to 20 kV. Nova (9) lithotriptor. In 5 of the 7 older children a Double J section sign stent was inserted before treatment. In the younger children group calculi were fragmented after 1 (11) or 2 (5) sessions. Of the 7 older children 3 required 3 (1) and 4 (2) treatment sessions. To assess the long-term effect of ESWL on the parenchyma, dimercapto-succinic acid renal scan was performed the day before and 6 months after therapy in 20 patients. RESULTS: Of the 16 younger children 14 became stone-free (87.5%) and 2 had small asymptomatic residual fragments. Of the 7 older children 5 were stone-free (71.4%) and 2 required additional surgery. No steinstrasse or pyelonephritis occurred after ESWL and no parenchymal or ureteral lesion related to ESWL was identified on conventional dimercapto-succinic acid scintigraphy. At a followup of 9 months to 9 years all patients have normal blood pressure. CONCLUSIONS: ESWL as a first option is safe and appropriate for the treatment of staghorn calculi in children particularly in younger children with infected calculi.

Adolescent↗
PubMed2000

[Histopathological evaluation of vitamin E derivatives effects on the healing process of a model of filtration surgery].

PURPOSE: To describe the effect of alpha-tocopherol derivatives (acetate and acid succinate) on the histopathological characteristics of the surgical fistulae in an experimental model of filtering surgery. METHODS: 30 pigmented rabbits were randomly divided into 3 study groups. Twenty-four hours before surgery the animals were injected subconjunctivally with 0.5 ml of solution: group I (n=10) 0.75% ethanol in balanced saline solution (BSS), group II (n=10) 100 microgrs alpha-tocopherol acetate (AT) in 0.75% ethanol in BSS, group III (n=10) 100 microgrs alphatocopherol acid succinate (ST) in 0.75% ethanol in BSS. Histological findings were evaluated 30 days after surgery. RESULTS: The groups treated with alpha-tocopherol derivatives showed a higher percentage of fistular persistence and smaller wound healing areas. There was a subconjunctival cellular infiltrate of mononuclear and eosinophilic cells. CONCLUSIONS: Histological findings support the clinical use of alpha tocopherol derivatives, AT and ST. to inhibit the wound healing processes associated to filtering surgery failure.

Animals↗
PubMed2005

Anion-induced water flux as drug release mechanism through cationic Eudragit RS 30D film coatings.

The objective of this study was to investigate the anion-controlled drug release mechanism through the cationic coating polymer Eudragit RS 30 D as a function of the anion attraction toward the polymer's quarternary ammonium group (QAG), anion valence, and film composition. The mechanism was investigated by dissolution testing, determination of chloride ion exchange using ion chromatography, plasticizer leaching by means of differential scanning calorimetry, and water uptake by Karl Fischer titration. All experiments were performed on coated theophylline micro tablets or isolated films of various compositions using 0.01 M sodium nitrate, sodium sulfate, disodium succinate, sodium acetate, and succinic acid as dissolution media. The mechanism of drug release involved an immediate penetration of dissolution medium into the polymer followed by an instant exchange of chloride against the medium's anion species at completely different rates compared with the drug release. Dependent on the attraction of the anion toward the QAGs, a water flux was induced by back and forth exchanging anions. Strong attraction (nitrate, sulfate) resulted in a low water flux while weak attraction resulted in a high flux (acetate, succinic acid). The water flux increased at increasing number of QAGs. Plasticizer acted as a diluent in respect of the number of QAGs, thus higher plasticizer concentrations led to lower drug release.

Acrylic Resins↗
PubMedDate not supplied

Alpha-tocopherol derivatives and wound healing in an experimental model of filtering surgery.

OBJECTIVE: To describe the effect of alpha-tocopherol derivatives (acetate and acid-succinate) on the histopathological characteristics of the surgical fistula in an experimental model of filtering surgery. MATERIALS AND METHODS: Thirty pigmented rabbits were divided into 3 groups. Twenty-four hours before surgery the animals were injected subconjunctivally with 0.5 mL of solution that depended on the group of treatment: Group 1 (n = 10) 0.75% ethanol in balanced salt solution (BSS); Group 2 (n = 10) 100 microg alph-tocopherol-acetate in 0.75% ethanol in BSS; Group 3 (n = 10) 100 microg alpha-tocopheryl-acid-succinate in 0.75% ethanol in BSS. Histological findings were evaluated 30 days after surgery. RESULTS: The groups treated with alpha-tocopherol derivatives showed a higher percentage of persistence of the fistula and better intraocular pressure (IOP) control. CONCLUSIONS: Alpha-tocopherol derivatives showed antiproliferative properties in this experimental model of filtering surgery.

Animals↗
PubMed1993

Respiratory, ionic, and functional effects of succinate esters in pancreatic islets.

The methyl esters of succinic acid were introduced a few years ago as new potent insulin secretagogues. In the present study, they were found to increase O2 uptake by rat islets incubated in the absence or presence of D-glucose; to decrease 86Rb outflow from prelabeled islets; to stimulate biosynthetic activity in the islets, with a preferential effect on the synthesis of proinsulin; to inhibit 45Ca efflux from prelabeled islets perifused in the absence of extracellular Ca2+ but to augment 45Ca net uptake and to cause a biphasic stimulation of 45Ca outflow in islets incubated or perifused in the presence of extracellular Ca2+; and to evoke a biphasic stimulation of insulin release. The insulinotropic action of these methyl esters coincided with a shift to the left of the sigmoidal relationship between insulin output and D-glucose concentration, was concentration related in the 2-10 mM range, failed to be duplicated by succinic acid, displayed both Ca2+ dependency and resistance to a lowering of extracellular pH, and was operative in the absence of D-glucose whether or not the islets were stimulated by non-nutrient secretagogues. It is concluded that the respiratory, cationic, biosynthetic, and secretory responses of the islets to succinate methyl esters display the characteristic features usually encountered in the process of nutrient-stimulated insulin release.

Animals↗
PubMed1997

Effects of glycerol-1,2-dimethylsuccinate and propanediol-1,2-dimethylsuccinate on insulin release and protein biosynthesis in islets of Goto-Kakizaki rats.

Selected esters of succinic acid are currently under investigation as possible insulinotropic tools in the treatment of non-insulin-dependent diabetes mellitus. Novel esters with high insulinotropic efficiency were recently synthesized. The present study concerns the effects of two of these novel esters, namely glycerol-1,2-dimethylsuccinate (2.5 mM) and propanediol-1,2-dimethylsuccinate (1.0 mM), upon the release of insulin and the de novo biosynthesis of peptides in islets from hereditarily diabetic Goto-Kakizaki rats. Whereas D-glucose (2.8 to 16.7 mM) caused a concentration-related stimulation of insulin release in the islets of the diabetic rats, the two esters of succinic acid only increased modestly, and often not significantly, insulin secretion. Nevertheless, they both markedly increased the incorporation of L-[4-3H]phenylalanine into trichloroacetic acid-precipitable material in islets deprived of any other exogenous nutrient. These findings indicate that, at variance with all pharmaceutical agents presently used or proposed as insulin secretagogues in the treatment of type 2 diabetes, glycerol-1,2-dimethylsuccinate and propanediol-1,2-dimethylsuccinate, considered as islet cell nutrients, display, in addition to their insulinotropic action, the property of stimulating biosynthetic activity in the endocrine pancreas of animals affected by this disease.

Animals↗
PubMed1994

Comparison of IR- and UV-matrix-assisted laser desorption/ionization mass spectrometry of oligodeoxynucleotides.

UV-matrix assisted laser desorption/ionization mass spectrometry (UV-MALDI-MS) with 3-hydroxypicolinic acid as matrix and IR-MALDI-MS with succinic acid as matrix have proved their feasibility for highly accurate and sensitive mass determination of nucleic acids (DNA and RNA). In this work, a detailed comparison of these two MALDI-methods and between positive- and negative ion mass spectra for the analysis of oligodeoxynucleotides is undertaken. Mass spectra of DNA sequences with up to 40 nucleotides are shown. Both linear and reflectron time-of-flight mass analyzers were used within this study and are compared for their potential in the MALDI analysis of oligodeoxynucleotides. The role of molecule-ion fragmentation is also discussed.

Base Sequence↗
PubMed2001

Cessation of prophylactic antibiotics for managing persistent vesicoureteral reflux.

PURPOSE: We reviewed our experience with patients with vesicoureteral reflux treated off prophylactic antibiotics. MATERIALS AND METHODS: We retrospectively reviewed the records of patients with vesicoureteral reflux treated off prophylactic antibiotics, noting the intervals on and off antibiotics, urinary tract infection, signs and symptoms associated with urinary tract infection, and renal ultrasound and dimercapto-succinic acid scan findings. RESULTS: We identified 196 patients with vesicoureteral reflux treated off prophylactic antibiotics, including 122 who were infection-free while on and 124 who had no urinary tract infection while off prophylactic antibiotics. The infection rate on and off prophylactics was 0.29 and 0.24 urinary tract infections per patient per year, respectively. New scars were identified in 5 patients while on prophylactics and in 7 after antibiotics were discontinued. Comparing different subgroups off prophylactic antibiotics showed that children who presented with scarring had statistically fewer new scars than those with normal initial dimercapto-succinic acid imaging (p <0.043). Girls had significantly more urinary tract infections than boys while off prophylactics (p <0.01) despite the older age at antibiotic cessation. However, after infection occurred while off prophylactic antibiotics, new renal scars developed at about the same rate in boys and girls. Because most patients did not have a urinary tract infection while off prophylactic antibiotics, new renal scars developed in only 2.2% of all boys and 4% of all girls. CONCLUSIONS: Our findings imply that discontinuing antibiotics is reasonable and safe in patients in whom vesicoureteral reflux fails to resolve.

Antibiotic Prophylaxis↗
PubMed2026

Comparison of culture and culture-free methods for comprehensive identification of mycobacteria: a single-center prospective study.

The genus Mycobacterium, including Mycobacterium tuberculosis and over 200 nontuberculous mycobacteria (NTM), shows wide variability in clinical outcomes and drug susceptibility. Although culture-based identification remains the gold standard, slow mycobacterial growth delays diagnosis and treatment. In this study, we evaluated a novel culture-free method for subspecies-level identification directly from sputum. In this single-center prospective cohort study at Osaka Toneyama Medical Center, we analyzed 125 sputum samples from 115 patients with NTM pulmonary disease and 10 with non-NTM respiratory conditions. Samples were decontaminated using N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) or succinic acid. We compared the reference culture method (mycobacterial culture plus whole-genome sequencing) and a culture-free direct target capture sequencing method. Core genome multi-locus sequence typing identified subspecies in both workflows, covering 186 mycobacterial species, including M. tuberculosis. The 115 NTM cohort specimens yielded 57 smear-positive and 93 culture-positive results. The identified subspecies included 48 Mycobacterium avium subsp. hominissuis, 22 Mycobacterium intracellulare subsp. intracellulare, 5 subsp. chimaera, 7 Mycobacterium abscessus subsp. abscessus, 5 subsp. massiliense, 1 M. tuberculosis, and 5 other NTM species. The culture-free method showed a high identification rate for smear-positive specimens (75.4%) but a low identification rate for smear-negative specimens (13.9%). NALC-NaOH pretreatment resulted in higher accuracy (90.5%) than did succinic acid pretreatment (66.7%). Thus, our culture-free subspecies-level identification method achieved high accuracy, especially in alkaline-treated smear-positive sputum samples, achieving rates above 90%. This method is recommended in clinical practice for patients who require rapid diagnosis and timely initiation of appropriate treatment, bypassing time-consuming culture steps.IMPORTANCEAccurate identification of Mycobacterium species and subspecies is crucial for effective treatment, as drug susceptibility and clinical outcomes vary significantly among them. However, conventional diagnosis relies on culture-based methods that can take several weeks, critically delaying appropriate therapy. This study validates a novel culture-free method using target capture sequencing for the comprehensive, subspecies-level identification of over 186 mycobacterial species directly from sputum specimens. Our findings revealed the high accuracy of this approach for smear-positive specimens, especially with alkaline pretreatment. This rapid method is applicable in clinical settings and enables timely and precise treatment decisions, greatly benefiting patients who require urgent intervention.

Humans↗
PubMed2004

Percutaneous nephrolithotomy in children: early and late anatomical and functional results.

PURPOSE: We report our experience with percutaneous nephrolithotomy (PCNL) in children, and evaluate its early and late anatomical and functional results. MATERIALS AND METHODS: A total of 65 children with renal calculi were treated with PCNL. Patient age at operation ranged from 9 months to 16 years (mean +/- SD of 5.9 +/- 0.9 years), and 27 (41.5%) were younger than 5 years. Seven patients had bilateral renal stones and, therefore, the number of kidneys treated by PCNL was 72. The patients were followed regularly every 3 months during year 1 and every 6 months thereafter. Renal scans using technetium dimercapto-succinic acid for detection of renal scarring and technetium diethylenetetramine-pentaacetic acid for determination of selective glomerular filtration rate (GFR) were performed in all patients at least once during followup, which ranged from 6 to 72 months (mean +/- SD 40 +/- 10). RESULTS: Early complications included significant intraoperative bleeding in 1 case, renal pelvis perforation in 1 and transient fever in 2. Mean hospital stay +/- SD was 3 +/- 1.2 days (range 2 to 21). Of the renal units 62 (86%) were stone-free after a single PCNL, and the remaining 10 with residual stones were treated with a second look PCNL (4) and shock wave lithotripsy (6). Stone-free rates at hospital discharge and at 3 months were 93% and 100%, respectively. During followup 6 patients (9%) had recurrence of small renal stones and were successfully treated with shock wave lithotripsy. None of the kidneys had scarring on dimercapto-succinic acid renal scan. All of the kidneys except 1 showed improvement or stabilization of the corresponding GFR determined by diethylenetetraminepentaacetic acid renal scan. Comparison of the mean preoperative GFR of the corresponding kidney (28.8 +/- 11.2 ml per minute) with mean value at followup (36.1 +/- 9.9) showed an increase of statistical significance (p <0.01). CONCLUSIONS: PCNL is a safe and effective procedure for the treatment of children with renal calculi. At long-term followup the procedure improves renal function without renal scarring.

Adolescent↗
PubMed1997

[Chemical composition of Fagopyrum cymosum (Trev.) Meisn].

From the ethanolic extracts of the aerial parts of Fagopyrum cymosum, eleven compounds were isolated, of which eight have been identified as benzoic acid(1), beta-sitosterol(2),5,5'-di-alpha-furaldehyde dimethyl ether(3), p-hydroxybenzoic acid(4), rutin(5), quercetin(6), daucosterol(7), succinic acid(8) by spectroscopic methods. Compound 3 is obtained from the genus for the first time.

Drugs, Chinese Herbal↗
PubMed1996

[The cytochemical observation of inosine effect on glucose metabolism of BGC-823 human gastric carcinoma cell line].

The activity of intracellular lactic acid dehydrogenase (LDH) and succinic acid dehydrogenase (SDH) was studied by cytochemistry in BGC-823 gastric carcinoma cell line treated with inosine. Cytoplasmic granules of LDH were found decreased or completely disappeared, while little change of SDH was observed. The tumor cells were decreased in number and became atrophic, especially when the cells were treated with high concentrations of inosine. The results suggest that inosine can play a role in suppressing the activity of intracellular LDH, thus blocking the major source of energy supply of cancer cells.

Energy Metabolism↗
PubMed2004

Simultaneous quantitative analysis of isobars by tandem mass spectrometry from unresolved chromatographic peaks.

A method was developed for the simultaneous quantitation of isobars from unresolved chromatographic peaks. The method is based on differences in branching ratios of ion abundances in their tandem mass spectra and an assumption that the product ion mass spectra of a mixture can be considered as a linear combination of the spectra of individual constituents. We present analytical equations and a matrix-based approach for deconvoluting the concentration of individual components from the total peak intensity for two and three isobars and also a matrix-based generalization to any number of compounds. The feasibility of the simultaneous analysis of mixtures containing two compounds was assessed. The approach was evaluated for the analysis of structural isomers of methylmalonic and succinic acids in human plasma and urine samples for a group of 270 samples. The linear regression equation, standard error and correlation coefficient for the agreement with a traditional method utilizing chromatographic separation of the isomers were y = 0.999x - 0.005, 0.024 micro mol l(-1), and 0.985, respectively. The utility of a spectral contrast angle as a predictor of analysis feasibility was evaluated.

Algorithms↗
PubMed1983

[Regulation of glyoxylate cycle enzymes in Saccharomycopsis lipolytica. I. Effect of the carbon source on isocitrate lyase and malate synthase activity].

Comparative studies on the activities of isocitrate lyase (ICL) and malate synthase (MS) were carried out with Saccharomycopsis lipolytica incubating the yeast on media with different carbon sources. When cells were incubated in minimal medium with glucose, the activities of both enzymes were very low. In contrast, in minimal medium with acetate enhanced enzyme activities could be demonstrated. It is probably that the synthesis of ICL is repressed in presence of glucose. Furthermore the activity of ICL was inhibited by tricarboxylic acid cycle intermediates like succinic acid and oxalacetic acid. It was concluded that the syntheses of enzymes are derepressed. When cells of Sm. lipolytica were incubated in minimal medium with acetate, a high enzyme activity is evident. Synthesis of ICL on acetate was inhibited by cycloheximide and actinomycin D. The results were discussed comparing them with data obtained from other organisms.

Acetates↗
PubMed1993

Ion-exchange liquid chromatographic analysis of bisphosphonates in pharmaceutical preparations.

A simple, fast and uniform method has been developed for the quantitative determination of bisphosphonates in the quality control of pharmaceutical preparations. The method is based on ion-exchange liquid chromatography with conductivity detection. Separation is performed on a Waters IC-PAK Anion column using 2 mM nitric acid or 25 mM succinic acid as the mobile phase. Retention of the bisphosphonates can be influenced by pH and the anion concentration of the mobile phase. Sensitivity and selectivity are sufficient for the assay of bisphosphonates in bulk drug and pharmaceutical preparations. Sample preparation comprises dissolution or dilution of the sample in the mobile phase followed, if necessary, by filtration prior to HPLC analysis. Since the method is stability indicating, it is also well suited for shelf-life studies of bisphosphonate pharmaceutical preparations. Validation of the analytical method for the assay of pamidronate injection indicated an intra-day reproducibility of 1.7% (n = 6) and an inter-day reproducibility of 2.7% (n = 6). A linear relationship between response and concentration was found in the concentration range studied from 200 ng to 10 micrograms pamidronate per 20 microliters injected. The lower limit of detection (signal-to-noise ratio = 3) of pamidronate was about 100 ng.

Chemistry, Pharmaceutical↗