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PubMed1986

Quantitative gas chromatographic analysis of volatile fatty acids in spent culture media and body fluids.

Gas chromatographic analysis of volatile fatty acids for identification of obligately anaerobic bacteria and for presumptive diagnosis of anaerobic infections is now widely practiced. However, it is difficult to compare data because only a qualitative analysis is done or only chromatograms are presented instead of quantitative data on volatile fatty acid production. We compared three stationary phases for volatile fatty acid analysis of aqueous solutions and four methods of pretreating samples for gas chromatography. Quantitative analysis could be done accurately by using Carbowax as the stationary phase after pretreatment of spent culture media with Dowex columns. If only qualitative analysis is required (e.g., for presumptive diagnosis of anaerobic infections), ether extraction and headspace analysis are equally suitable. The overall variation coefficient for volatile fatty acid production by four reference strains of obligately anaerobic bacteria after 24 h of incubation was approximately 10%.

Bacteria, Anaerobic↗

PubMed2003

Apoptotic-regulatory and complement-protecting protein expression in chronic lymphocytic leukemia: relationship to in vivo rituximab resistance.

PURPOSE: Rituximab has clinical activity in patients with chronic lymphocytic leukemia (CLL) and has a variety of proposed mechanisms, including apoptosis, complement-dependent cell lysis (CDC), and antibody-dependent cellular cytotoxicity (ADCC). Here we examine pretreatment biologic features that promote resistance to apoptosis and CDC in CLL patients and correlate it with clinical outcome to rituximab-based therapy. PATIENTS AND METHODS: Pretreatment samples from 21 CLL patients treated on a prospective, single-agent rituximab trial were examined for quantitative expression of apoptotic and CDC regulatory proteins, and the level of expression of these proteins was correlated with clinical outcome. RESULTS: Of the 21 patents for whom samples were available, 10 attained a partial response and 11 failed to respond to rituximab therapy. The mean pretreatment expression of Bcl-2, Mcl-1, XIAP, and the ratio of Bcl-2/Bax were higher but not statistically increased in nonresponding patients versus those responding to treatment. In contrast, the pretreatment Mcl-1/Bax ratio was significantly elevated (0.82 +/- 0.28 v 0.39 +/- 0.29, P <.016) in nonresponding patients compared with patients responding to rituximab therapy. Although pretreatment expression of CD55 and CD59 was not associated with response to rituximab therapy, significantly higher levels of CD59 were observed in the CLL cells that were not cleared from the blood at completion of therapy than the level observed at baseline levels (P =.02). CONCLUSION: These data indicate that baseline expression of the Mcl-1/Bax ratio, but not CD55 and CD59, predict for clinical response to rituximab therapy in CLL patients. Further study of disrupted apoptosis in CLL as a potential mechanism of resistance to rituximab appears warranted.

Antibodies, Monoclonal↗

PubMed1999

[Measurement of cadmium content in soils and vegetables by FAAS].

The analytical and testing centre the total cadmium (Cd) and the available Cd contents in different Cd-polluted soils were measured by FAAS. The Cd content in the stems and leaves of cole was tested in the same way. The methods of sample pretreatment for the total Cd and available Cd in soils and in cole were compared respectively. The standard sample recovery rates were all above 96 percent, and the relative standard deviations were less than 3.97 percent. The FAAS is rapid and accurate.

Brassica↗

PubMed1982

Fluorescence polarization immunoassay IV. Determination of phenytoin and phenobarbital in human serum and plasma.

Fluorescence polarization immunoassays for phenytoin and phenobarbital in human serum or plasma are described and shown to be clinically useful. No sample pretreatment, extraction, or phase separation is required. A determination can be made with less than 20 microL of sample in 15 min, with incubation at ambient temperature. Abnormal concentrations of protein, lipid, hemoglobin, or bilirubin do not interfere. In addition, drug metabolites and commonly co-administered drugs do not affect the assay results at clinically significant concentrations. Analytical recoveries of each of the two anticonvulsant drugs from serum averaged 101%. Between-assay CVs were less than 6.5%, with sensitivities of 0.5 mg/L. Comparison of this method with "high-performance" liquid chromatography, homogeneous enzyme immunoassay, and radioimmunoassay for phenytoin determinations yielded correlations of 0.99, 0.98, and 0.99, respectively. Similar comparison studies for phenobarbital yielded correlation coefficients of 0.99, 0.98, and 0.99, respectively.

Chromatography, High Pressure Liquid↗

PubMed1993

A simple method for the determination of articaine and its metabolite articainic acid in dentistry: application to a comparison of articaine and lidocaine concentrations in alveolus blood.

This study was undertaken to develop a time- and cost-effective method for the detection of articaine and articainic acid in alveolus blood by high-performance liquid chromatography with a simple method of sample pretreatment. To overcome the problem of very rapid hydrolysis a method for controlling hydrolysis in vitro after blood sampling was developed. Blood samples were withdrawn from the alveolus of the upper molars 2-14 min after submucous injection of articaine (2.0 ml 4%) or identical injection of lidocaine (2.0 ml 2%). The higher blood levels found for articaine correspond to the higher concentration of the drug in the injection solution. A relationship between the serum concentration of articaine and lidocaine, respectively, and the time between injection and blood sampling could be established.

Alveolar Process↗

PubMed1992

Collagen III aminoterminal propeptide in gingival crevicular fluid before and after periodontal treatment.

The amount of procollagen III aminoterminal propeptide (PIIINP) in crevicular fluid (CF) was measured from three periodontitis patients before treatment (scaling, root planing, and curettage) and 2, 5, 10, 20, and 40 days after treatment. CF was collected by placing two paper strips in each pocket for 5 s, after which the amount of fluid was measured. Control samples were collected from three subjects with minimal gingival inflammation. PIIINP was extracted into saline solution and determined by a radioimmunological method. Plaque Index, Papilla Bleeding Index, and pocket depth were recorded before and 40 days after treatment. Forty days after treatment clinical parameters indicated healing. The CF PIIINP mean concentration was 162 micrograms/l (range 0-430) in the pretreatment samples. Ten days after treatment, PIIINP mean concentration was 1400 micrograms/l (range 1000-9000). After this, the concentration gradually decreased, reaching the pretreatment level 40 days after treatment. Most of the control samples showed undetectable amounts of PIIINP. It was suggested that elevated PIIINP concentrations in CF after periodontal treatment reflected increased type III collagen synthesis in gingiva. PIIINP concentrations before treatment reflected the rate of type III collagen turnover in inflamed periodontal tissues. It was further suggested that CF PIIINP has clinical value as an indicator of the healing process of inflamed gingiva.

Adult↗

PubMed1989

Combined supercritical-fluid chromatography/mass spectrometry in the analysis of diuron in plasma using on-line phase-system switching.

On-line sample pretreatment by means of the phase-system switching approach is an interesting technique for the analysis of aqueous samples, e.g., plasma, by means of supercritical-fluid chromatography. In order to analyse plasma samples the following analytical procedure is used. The plasma sample is injected on to a short precolumn, which is washed with water and subsequently dried with nitrogen. Next, the solutes are desorbed with the supercritical mobile phase, analysed with packed-column supercritical-fluid chromatography and detected with either a UV detector or a mass spectrometer, equipped with a moving-belt interface. The herbicide diuron is selected as a test compound to study the feasibility of this approach. Using a selective detector the procedure is sufficiently sensitive to detect diuron in plasma, but not appropriate to detect the diuron metabolites in a post-mortem plasma sample. These have been identified with liquid chromatography/mass spectrometry. The detection limit of diuron in plasma using the procedure described is about 30 ng/mL.

Chromatography, High Pressure Liquid↗

PubMed1989

Analysis of water-soluble vitamins in total parenteral nutrition solution by high pressure liquid chromatography.

A stability-indicating high pressure liquid chromatographic method was developed to determine the stability of water-soluble vitamins in total parenteral nutrition mixtures. Folic acid and thiamine were determined by direct injection and precolumn enrichment, followed by UV detection. Nicotinamide and pyridoxine were determined simultaneously without sample pretreatment by UV detection of nicotinamide and fluorescence detection of pyridoxine. Riboflavin 5'-phosphate was also determined without elaborate sample handling and by fluorescence detection. Ascorbic acid was determined as the sum of ascorbic acid and dehydroascorbic acid. After derivatization to a quinoxaline the latter substance was determined by direct injection and fluorescence detection.

Ascorbic Acid↗

PubMed1990

High-performance liquid chromatographic analysis of the new antitumour drug SK&F 104864-A (NSC 609699) in plasma.

A high-performance liquid chromatographic (HPLC) assay is described for the determination of the new, investigational antitumour drug SK&F 104864-A and its lactone ring opened form (SK&F 105992). The analytical methodology reported here involves a protein precipitation step with methanol as sample pretreatment procedure. The instability of the drug necessitates that the plasma fraction is obtained within 5 min after blood sampling by centrifugation, immediately followed by protein precipitation with cold methanol (-30 degrees C). The methanolic extract can be stored at -30 degrees C for several days without deterioration of the analyses. Stability data of the drug and its lactone ring opened metabolite in plasma and after methanolic extraction are discussed. The parent drug and the metabolite are separated by reversed-phase ion-pair liquid chromatography on a LiChrosorb RP-18 column, using methanol-water eluent (pH 6.0) with sodium dioctylsulphosuccinate (DOSS) as ion-pairing agent and fluorescence detection. The proposed method has been validated and, subsequently, implemented in a phase I clinical trial for pharmacokinetic evaluation of the new cytotoxic agent.

Aged↗

PubMed2000

Advances in the determination of inorganic anions by ion chromatography.

The time period covered for this review includes articles published from 1997 to 1999, with the addition of a few classic references. The purpose of the review is to include the most relevant works from each topic area of the determination of inorganic anions by ion chromatography, including new sample pretreatments, new separation methods, new detection systems and the latest applications in the field of environmental, water, foods, etc. samples. Experimental conditions such as stationary phase, eluent, detection mode, as well as matrix are summarized in a table.

Anions↗

PubMed2001

Effects of heat pretreatment on histopathology, cytokine production, and surfactant in endotoxin-induced acute lung injury.

To determine the effect of heat stress on histopathology of acute lung injury (ALI) caused by administration of lipopolysaccharide (LPS), and to determine the roles of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, interferon (IFN)-gamma, IL-10 and surfactants in heat-induced tolerance to ALI, we administered either saline or LPS (3 mg/kg of body weight) intravenously to male Sprague-Dawley rats without and with heat pretreatment. Five hours after LPS or saline treatment (23 h after heat-pretreatment), samples were obtained. We found that the histopathologic features of LPS-induced ALI were attenuated by heat-pretreatment. Heat-pretreatment did not decrease the elevated plasma or BAL fluid levels of TNF-alpha, IL-1beta, and IFN-gamma by LPS. The plasma level of IL-10 in LPS-treated rats with heat-pretreatment, however, was increased compared to that of LPS-treated rats without heat-pretreatment (P = 0.001). There were no differences in the BAL fluid concentrations of light or heavy density pulmonary surfactant phospholipids depending on heat-pretreatment in LPS-treated rats. These observations suggest that IL-10 might play a role in decreasing LPS-induced acute lung injury after heat-pretreatment.

Acute Disease↗

PubMed2001

Efficient extraction of virus DNA by NucliSens Extractor allows sensitive detection of hepatitis B virus by PCR.

The NucliSens Extractor is an automated nucleic acid isolation system based on guanidinium thiocyanate (GuSCN)-silica extraction technology. The system has been validated for the isolation of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) RNAs from human samples in combination with nucleic acid sequence-based amplification- and reverse transcription-PCR-based methods. We evaluated the extractor for hepatitis B virus (HBV) DNA extraction from human samples using a noncommercial HBV DNA PCR. Several sample pretreatment procedures in combination with the extractor were compared with the Qiagen extraction method, and the impact of the sample volume used in the extraction on the sensitivity was investigated. Heating of the lysed sample prior to extractor isolation and the use of a large sample volume resulted in highly sensitive detection of HBV DNA. Incubation of a 1-ml sample in GuSCN at 80 degrees C (10 min) and at 37 degrees C (30 min) allowed detection of 4 and 40 HBV genome equivalents/ml, respectively, in standard dilution panels. Sample lysis in GuSCN at room temperature and proteinase K treatment prior to use of the extractor were less efficient procedures. All clinical samples that were PCR positive after Qiagen extraction and/or that were HBsAg positive were also PCR positive after extractor isolation. HBV DNA, HCV RNA, and HIV type 1 RNA were efficiently coextracted from a single sample, allowing reliable detection of viral genomes.

DNA, Viral↗

PubMed2000

Determination of residual solvents in bulk pharmaceuticals by thermal desorption/gas chromatography/mass spectrometry.

Thermal desorption (TD) techniques followed by capillary GC/MS were applied for the analysis of residual solvents in bulk pharmaceuticals. Solvents desorbed from samples by heating were cryofocused at the head of a capillary column prior to GC/MS analysis. This method requires a very small amount of sample and no sample pretreatment. Desorption temperature was set at the point about 20 degrees C higher than the melting point of each sample individually. The relative standard deviations of this method tested by performing six consecutive analyses of 8 different samples were 1.1 to 3.1%, and analytical results of residual solvents were in agreement with those obtained by direct injection of N,N-dimethylformamide solution of the samples into the GC. This novel TD/GC/MS method was demonstrated to be very useful for the identification and quantification of residual solvents in bulk pharmaceuticals.

Chemistry, Pharmaceutical↗

PubMed2001

Enzymes and chelating agent in cotton pretreatment.

Desized cotton fabric and cotton seed-coat fragments (impurities) have been treated with commercial cellulase (Celluclast 1.5 L), hemicellulase-pectinase (Viscozyme 120 L) and xylanase (Pulpzyme HC) enzymes. Seed-coat fragments hydrolyzed much faster than the cotton fabric itself. This relative difference in hydrolysis rates makes possible a direct enzymatic removal of seed-coat fragments from desized cotton fabric. Addition of chelating agents such as ethylenediamine-tetra-acetic acid (EDTA) markedly enhanced the directed enzyme action. Pretreatments carried out in acidic solution at pH 5 increased the lightness of seed-coat fragments, contrary to the samples treated in neutral medium at pH 7. Alkaline scouring resulted in darker seed-coat fragments except for the samples pretreated with Pulpzyme HC plus EDTA. This effect is similar to that observed in the biobleaching process in pulp and paper industry.

Calcium↗

PubMed1998

Liquid chromatographic determination of irinotecan and three major metabolites in human plasma, urine and feces.

A new simple reversed-phase high-performance liquid chromatographic method was developed for the determination of irinotecan (CPT-11) and three metabolites in human plasma, urine and feces homogenate. The metabolites of interest were 7-ethyl-10-hydroxycamptothecin (SN-38), its beta-glucuronide derivative (SN-38G) and 7-ethyl-10-[4-N-(5-aminopentanoic acid)-1-piperidino]carbonyloxycamptothecin (RPR 121056A; also referred to as APC). Sample pretreatment from the various biological matrices involved a rapid protein precipitation with simultaneous solvent extraction of 250-microl aliquots of sample with 500 microl of methanol-5% (w/v) aqueous perchloric acid (1:1, v/v). Separation of the compounds was achieved on an analytical column packed with Hypersil ODS material (100X4.6 mm I.D., 5 microm), and isocratic elution with a mixture of methanol-0.1 M ammonium acetate containing 10 mM tetrabutylammonium sulphate (30:70, v/v), pH 5.3 (hydrochloric acid). The column effluent was monitored at excitation and emission wavelengths of 355 and 515 nm, respectively. Results from a 4-day validation study indicated that this single-run determination allows for simple, simultaneous and rapid quantitation and identification of all analytes with excellent reliability. The described procedure permits the analysis of patient samples, and will be implemented in future studies to investigate the complete metabolic fate and disposition of CPT-11 in cancer patients.

Camptothecin↗

PubMed2005

A new analysis method with GC or GC-MS for the quick detection of pesticide residues in vegetables.

A new analytical method for gas chromatography (GC) or GC-mass spectrometry (MS) using the direct sampling technique is described. This direct sampling technique, which bypasses the conventional complicated sample pretreatment process, is applicable to cases of fast detection of pesticide residues in foods and large-scale screening of samples by portable GC in field detection. By a direct sampling technique, the vegetable sample is ground into paste, and 30 mg is placed directly into the evaporating chamber for GC-MS identification and quantitation (by full-scan mode). The GC column used is an HP-5 (30.0-m x 250-microm x 0.25-microm, 5% phenyl methyl siloxane). Chlorpyrifos, bromophos, fenpropathrin, gamma-666, and pp'-DDT are chosen to represent organophosphorus, pyrethrins, and organochlorine pesticides because they are chief objects of the detection of pesticide residues in vegetables. Rape, a common and mass-consumed vegetable in China, is chosen as the sample in this study. The detection limits for these pesticides by the full-scan mode are all below the maximum pesticide residue limit of vegetables set by the Ministry of Agriculture of China, and the reproducibility of this method is acceptable. This analysis method is proven to be simple, quick, and reliable and is suitable for multipesticide residues analysis of vegetables. It can also be used in the analysis of vegetable components and signal chemicals.

Chromatography, Gas↗

PubMed2006

Trace element determination by combining solid-phase microextraction hyphenated to elemental and molecular detection techniques.

The state of the art of analytical procedures based on solid-phase microextraction (SPME) and its applications to tin, mercury, arsenic, antimony, chromium, selenium, and lead determination in abiotic and biotic matrixes are critically reviewed from 1994 to present. First, sample pretreatment prior to SPME is evaluated, including a description of the most usual leaching procedures for sediment, soil, and biological samples. Because most organometallic species lack volatility, a derivatization step is mandatory prior to gas chromatographic (GC) determination, except for the volatile organometallics that can be directly extracted from the sample headspace or liquid phase by SPME. The most common derivatization procedures used in alkylation and hydridization reactions used for mercury, lead, and tin, as well as other procedures for the determination of total chromium and arsenic [i.e., trifluoroacetylacetonates for chromium (III) and thioglycol methylate for organic arsenic species] are reviewed. Critical variables usually evaluated along with the method development to improve the sensitivity of the extraction methods based on SPME, such as sampling size, stirring procedures, sampling temperature and pressure, polymer coating, and thermal desorption are reviewed. In addition, figures of merit of the different detection systems used in SPME combined with GC are evaluated. The validation of the reported analytical procedures with reference materials are also discussed in terms of precision and accuracy. Finally, future developments in the application of SPME to speciation are highlighted. Moreover, the capability of SPME automation for the derivatization-extraction procedures are also presented.

Journal Article↗

PubMed2006

Rapid method for the analysis of plutonium isotopes in a soil sample within 60 min.

A rapid method for the determination of Pu isotopes in a soil sample within 60 min of starting sample pretreatment was developed. The large reduction in the analysis time was attained by the rapid and perfect digestion of the sample using an alkaline fusion method with an induction heating machine. Pu concentrations were then determined by flow injection/ICP-MS using a solid extraction resin after preconcentration by batch extraction with a chelate resin. The limits of detection for 239Pu and 240Pu were 9.2 fg and 4.3 fg, corresponding to 0.03 and 0.05 Bq kg(-1), respectively, under our analytical conditions, which satisfy the lower detection limits (0.5 Bq kg(-1) of 239Pu, and 2 Bq kg(-1) of 240Pu) required for rapid analysis techniques by the Ministry of Education, Culture, Sports, Science and Technology, Japan. This method provides a powerful and practical technique for emergency monitoring in and around nuclear facilities that handle large amounts of plutonium.

Journal Article↗