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At least 235 records · Page 13Linked to original sources
PubMed1987

Control of corneal astigmatism following cataract extraction by selective suture cutting.

We evaluated the ability of selective suture cutting to reduce postoperative corneal astigmatism in 75 eyes of 68 patients who underwent extracapsular cataract extraction with posterior chamber intraocular lens implantation. Keratometric and refractive measurements were obtained before and at selected intervals (3, 6, 10, 26, and 52 weeks) after surgery. The number of sutures cut during the sixth week after surgery was based on the degree of astigmatism (0.00 to 2.00 diopters (D), no sutures cut; 2.25 to 3.00 D, one suture cut; 3.25 to 4.00 D, two sutures cut; greater than or equal to 4.25 D, three sutures cut). Our analysis demonstrated the following: (1) a spontaneous reduction of 0.5 D in surgically induced astigmatism in eyes without suture cutting, (2) an additional reduction of 1.2 D in postoperative astigmatism for each suture cut, and (3) attainment of 75% to 93% of the total effect of suture cutting within four weeks. The final astigmatism one year after surgery had increased by a mean of 0.9 D, exhibited predominantly with-the-rule properties, and showed no significant difference among the four groups of patients. Vector analysis revealed that only small shifts in the axis of astigmatism occurred after suture cutting. A strong correlation between the keratometric and subjective refractive measurements during all postoperative examinations indicated that corneal astigmatism is primarily responsible for postoperative astigmatism.

Astigmatism↗
PubMed1994

Analgesic effects of callus culture extracts from selected species of Phyllanthus in mice.

The aim of this study was to evaluate the analgesic effect of the methanolic extract from callus culture of Phyllanthus tenellus, P. corcovadensis and P. niruri in several models of pain in mice. The extracts (medium containing 2,4-dichlorophenoxyacetic acid) of P. corcovadensis, P. niruri and P. tenellus (3-90 mg kg-1, i.p.) caused graded inhibition of abdominal constrictions induced by acetic acid (0.6%), with ID50 (i.e. dose that reduced response of control by 50%) values of about 30, 19 and > 30 mg kg-1, respectively. The extract of callus of Phyllanthus obtained in indole-3-butyric acid and indole-3-acetic acid media (3-90 mg kg-1, i.p.) caused a similar analgesic effect. In the formalin test, the extract of P. tenellus obtained in indole butyric acid medium (3-100 mg kg-1, i.p.) inhibited only the second phase of formalin-induced pain with an ID50 value of about 100 mg kg-1. Both the indole acetic acid and indole butyric acid methanolic extracts of P. tenellus and P. corcovadensis (10-100 mg kg-1, i.p.) dose-dependently inhibited both phases of formalin-induced pain (ID50 values for the second phase were approx. 100 and 52 mg kg-1, respectively). However, the extract of callus from Phyllanthus failed to affect formalin-induced paw oedema, as well as the response to radiant heat in the tail-flick test. In addition, the analgesic effect of morphine, but not the analgesic effects caused by Phyllanthus callus extract, was fully antagonized by naloxone.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗
PubMed1997

Extraction of functionally active photosystem 2 pigment-protein complexes from pea thylakoids and their purification on Sepharose DEAE 6B.

A method for selective extraction of photosystem 2 (PS 2) pigment-protein complexes (PPC) from pea thylakoids and their purification from Sepharose DEAE 6B was developed. It was shown that extraction of thylakoids (3 mg chlorophyll/ml) with Triton X-100 (Triton X-100:chlorophyll = 15-20:1 w/w) in the presence of 1 M sucrose, 1 M NaCl, 50 mM MES in the solubilization medium (pH 5.0), tenfold dilution with 50 mM MES buffer (pH 5.0), and centrifugation at 16,000 g for 10 min provided selective extraction of PS 2 PPC. Spectral, electrophoretic and functional properties of the isolated PPC were determined. This method allowed us to isolate native pigment-protein oxygen-evolving complexes (core complexes) and D1-D2-cytochrome b559 complexes of the reaction centre (RC). The core complex immobilized on a Sepharose DEAE 6B column was treated with 2 mM hydroxylamine or 1 M CaCl2. In the former case, modification by hydroxylamine led to the removal of 4 atoms of Mn, but not of the 33-kDa protein; in the latter case, modification by CaCl2 led to the removal of the 33 kDa protein. The modified core complexes were unstable upon native electrophoresis in the presence of n-dodecyl-beta-d-maltoside and deriphat-160. We suggest that the structural organization of the Mn cluster and 33 kDa protein stabilized the core complex and increased its stability upon the action of the detergents.

Chloroplasts↗
PubMed2004

Simple strategy for the optimization of solid-phase extraction procedures through the use of solid-liquid distribution coefficients application to the determination of aliphatic lactones in wine.

A practical strategy for the optimization of solid-phase extraction (SPE) systems is presented. Critical SPE volumes (sample loaded, rinsing and elution solvent) are calculated from solid-liquid extraction coefficients and from basic bed parameters determined in simple experiments, using the Lövkist Jonsson model and other expressions derived from the general theory of chromatography. The agreement between calculated and measured volumes is satisfactory, which makes it possible to consider different sorbents and rinsing and elution solvents in the SPE optimization with a relatively low experimental effort. The strategy has been successfully applied to the optimization of a SPE method directed to the selective extraction of aliphatic lactones from wine. Six different reversed-phase sorbents were studied and the one showing maximum extraction selectivity was selected. Wine (50 ml) is extracted in a 200 mg cartridge filled with Bond Elut-ENV resins. Interferences are removed with 20 ml of methanol-water (40:60) with 1% NaHCO3. Elution is carried out with 1.8 ml of dichloromethane. The extract is concentrated to 0.15 ml and analyzed by GC-ion trap MS. Eight odor-active aliphatic gamma and delta lactones (with 8-12 C atoms) from wine are recovered (R > 75%) in an extract free from wine major volatiles. Detection limits are in the 40-300 ng/l range, well below the odor detection threshold of these compounds. Linearity (r2 > 0.996) and precision (average R.S.D. 3.5%) are satisfactory in all cases. The levels in wine of some of these lactones (gamma-octa, undeca and dodecalactones) are reported by first time and results demonstrate that can be present at concentrations above or close to their corresponding odor thresholds.

Chromatography, Liquid↗
PubMed2000

RT-PCR from eosinophil-depleted leukocytes without RNA extraction: cell selection using streptavidin PCR tubes.

OBJECTIVES: The major RNase activity of leukocytes has been attributed to eosinophil-derived neurotoxin EDN. Depletion of eosinophils enables RT-PCR from 10(5) leukocytes without RNA extraction. In this study we introduced streptavidin-coated PCR tube strips for the selection of eosinophil-free leukocytes for RT-PCR analysis. DESIGN AND METHODS: Polypropylene 0.2 ml PCR tube strips were coated with streptavidin and biotinylated antibodies against cell surface antigens were attached to the tubes. CD7-positive T-lymphocytes, CD19-positive B-lymphocytes and CD16-positive cells (mainly neutrophils and monocytes) were positively selected by incubating of 1-2 x 10(5) leukocytes in the antibody-coated PCR tubes for 30 min at 23 degrees C. RESULTS: The mean amount of cells bound into a tube was 31,500 (CV25%) T-cells and 8,600 (CV61%) B-cells from 12 blood samples, and 23,600 (CV22%) CD16+ cells from 17 samples. The influence of selected cell lysate on the RT-PCR analysis of Philadelphia chromosome (bcr/abl translocation) from 100 K562 cells was small: 78% (CV28%) of the leukocyte-free signal was obtained in the presence of CD16+ cells or 89% (CV15%) and 99% (CV11%) and in the presence of T-cells and B-cells, respectively. CONCLUSIONS: These results suggest that through the introduction of eosinophil-free cell population into RT-PCR a reproducible method with reasonable leukocyte yield and avoiding RNA extraction was developed.

Adolescent↗
PubMed2003

Antimicrobial properties of commercial annatto extracts against selected pathogenic, lactic acid, and spoilage microorganisms.

Annatto preparations are used to impart distinctive flavor and color to foods and are a primary colorant in dairy foods such as cheese and butter. There are several reports indicating that certain fractions of the annatto plant have biological activities against microorganisms of significance in food fermentation, food preservation, and human health. However, little is reported describing the nature of the antimicrobial compound(s) or their potential presence in commercial annatto colorant preparations. This study was conducted to determine whether commonly available annatto extracts are capable of influencing the outgrowth of selected lactic acid, spoilage, and pathogenic microorganisms. Disk diffusion and tube macrodilution techniques were used to determine the MICs and MBCs of double-strength water-soluble annatto extracts. Standard antibiotic disks were used as controls for the disk diffusion assay. The results demonstrate that annatto has an inhibitory effect on Bacillus cereus, Clostridium perfringens, and Staphylococcus aureus, with MICs of 0.08, 0.31, and 0.16% (vol/vol) and diameters of inhibition of 9 to 10, 12 to 13, and 15 to 16 mm, respectively. A concentration of 0.63% (vol/vol) inhibited the growth of Streptococcus thermophilus, Lactobacillus casei subsp. casei, Lactococcus lactis, and Paenibacillus polymyxa. The MICs for Listeria monocytogenes and Enterococcus durans were 1.25 and 2.5% (vol/vol), respectively. No activity was detected against Lactobacillus plantarum, Bifidobacterium bifidum, yeasts, or selected gram-negative bacteria.

Bacteria↗
PubMed1997

Supercritical fluid extraction of selected pharmaceuticals from water and serum.

Selected drugs from benzodiazepine, anabolic agent and non-steroidal anti-inflammatory drug (NSAID) therapeutic classes were extracted from water and serum using a supercritical CO2 mobile phase. The samples were extracted at a pump pressure of 329 MPa, an extraction chamber temperature of 45 degrees C, and a restrictor temperature of 60 degrees C. The static extraction time for all samples was 2.5 min and the dynamic extraction time ranged from 5 to 20 min. The analytes were collected in appropriate solvent traps and assayed by modified literature HPLC procedures. Analyte recoveries were calculated based on peak height measurements of extracted vs. unextracted analyte. The recovery of the benzodiazepines ranged from 80 to 98% in water and from 75 to 94% in serum. Anabolic drug recoveries from water and serum ranged from 67 to 100% and 70 to 100%, respectively. The NSAIDs were recovered from water in the 76 to 97% range and in the 76 to 100% range from serum. Accuracy, precision and endogenous peak interference, if any, were determined for blank and spiked serum extractions and compared with classical sample preparation techniques of liquid-liquid and solid-phase extraction reported in the literature. For the benzodiazepines, accuracy and precision for supercritical fluid extraction (SFE) ranged from 1.95 to 3.31 and 0.57 to 1.25%, respectively (n = 3). The SFE accuracy and precision data for the anabolic agents ranged from 4.03 to 7.84 and 0.66 to 2.78%, respectively (n = 3). The accuracy and precision data reported for the SFE of the NSAIDs ranged from 2.79 to 3.79 and 0.33 to 1.27%, respectively (n = 3). The precision of the SFE method from serum was shown to be comparable to the precision obtained with other classical preparation techniques.

Anabolic Agents↗
PubMed1993

Augmentation of macrophage phagocytic activity by cell-free extracts of selected lactic acid-producing bacteria.

Oral and intraperitoneal administration of lactic acid-producing bacteria can significantly augment the immune response in murine models; however, the immunopotentiating effects in these studies differ significantly. Murine macrophagelike cell line J774 was cultured in the presence of cell-free extracts of Lactobacillus acidophilus and Bifidobacterium longum, and the effect on macrophage function was evaluated by measurement of synthesis of selected enzymes and their ability to take up either acrylamide particles or live Salmonella typhimurium. Lysozyme activity of J774 cells was significantly decreased by cell-free extracts of B. longum, but not of L. acidophilus, whereas extracts of both strains induced morphological changes and significantly enhanced phagocytosis of inert particles or viable Salmonella. Whole cell extracts of lactic acid-producing bacteria are therefore capable of altering macrophage function in a strain-dependent manner.

Animals↗
PubMed2002

Advanced solid phase extraction using molecularly imprinted polymers for the determination of quercetin in red wine.

Solid phase extraction (SPE) based on molecularly imprinted polymers (MIPs) is a novel approach for sample preparation and preconcentration, gaining increased interest in the fields of environmental, clinical, and food analysis. The first application combining MIPs with SPE for advanced beverage analysis is reported. MIPs for the flavonoid quercetin have been generated, using quercetin as a template molecule in a self-assembly approach and yielding imprinting of 1% of the used template. The MIP achieved a capacity of 0.4 g quercetin per gram polymer and a recovery rate of 98.2%. The application of these synthetic receptors as SPE material for the selective extraction and preconcentration of quercetin from synthetic and red wine samples was investigated. Red wine samples from a French Merlot were directly applied onto the SPE cartridge. The collected fractions were analyzed by high-pressure liquid chromatography. For verification of the obtained results, a similarly prepared nonimprinted polymer and a classical octadecyl silane reversed-phase cartridge were applied as the SPE matrix during control experiments. The MIP enabled the selective extraction of quercetin from a complex matrix, such as red wine, spiked with 8.8 mg per liter quercetin, demonstrating the potential of molecularly imprinted solid phase extraction for rapid, selective, and cost-effective sample pretreatment.

Acetonitriles↗
PubMed2005

Measuring bioavailability of polychlorinated biphenyls in soil to earthworms using selective supercritical fluid extraction.

If the release mechanisms during selective chemical extraction of persistent organic pollutants (POP) mimic release mechanisms in natural systems during biological uptake, then a selective non-exhaustive extraction could give a quantitative measure of the bioavailable POP fraction. Supercritical fluid extraction (SFE) is suggested as a possible technique to estimate the amount of bioavailable polychlorinated biphenyls (PCBs) at contaminated sites and hence serve as a new tool in risk assessment. The uptake of PCBs by earthworm (Eisenia foetida) was investigated. PCB contaminated soil was pre-extracted with selective non-exhaustive SFE (50 degrees C, 350 bar, 1h), which removed on average 70% of the individual PCBs. Earthworms were placed in this pre-extracted soil, as well as in untreated soil. After 10 days, the PCB uptake by earthworms in the two systems was compared. The bioaccumulation factor (BAF) was 83% lower in the pre-extracted system than in the untreated system, demonstrating that SFE extracts primarily bioavailable contaminants. From the data, the bioavailable fraction could also be calculated to be 75%, which is very close to the 70% removed by SFE under the applied conditions. This suggests that the chemical methodology is capable of measuring the bioavailable fraction very accurately in this system.

Animals↗
PubMed2000

Pharmacological activity and chemical composition of callus culture extracts from selected species of Phyllanthus.

This study was conducted in order to determine the chemical composition and the possible antinociceptive effects in mice of some species of Phyllanthus in vitro. The methanolic extracts obtained from callus cultures of P. fraternus, P. stipulatus and P. caroliniensis caused significant inhibition in to the late phase of the formalin test, whereas the extract from P. urinaria inhibited both neurogenic and inflammatory phases of the test. Conventional chromatographic methods (TLC, GC) permitted the detection of some steroids or triterpenes, including beta-sitosterol, glochidonol and glochidone, which seem be responsible for the antinociceptive effects of the callus extracts studied.

Acetaminophen↗
PubMed1982

Basic dyes in the staining of DNA-phosphate groups and DNA-aldehyde molecules in cell nuclei.

A novel method is presented for the staining of cell nuclei with aqueous solutions of Janus blue, methylene blue, and Janus red in tissue sections from which RNA has been extracted selectively with cold phosphoric acid. Not only this, DNA-aldehyde molecules can also be stained when tissue sections from which RNA has been extracted are then hydrolysed in 6 N hydrochloric acid at 30 degrees C for 15 min followed by staining with Janus blue, methylene blue, and Janus red. Following staining with any of these dyes, sections can be dried between folds of filter paper and then treated with n-butanol or passed through grades of ethanol, cleared in xylene and mounted. Staining with Janus blue has been considered to be metachromatic, particularly in the sections of the rectum in which glycogen stains blue-black and the nuclei purplish. An aqueous solution of methylene blue does also stain glycogen blue with similar colour of the nuclei while with Janus red both the nuclei as well as glycogen stain red. The in situ absorption spectra of the nuclei stained with the dyes mentioned, after selective extraction of RNA, reveal peaks of maximum absorption at 560-570 nm (Janus blue), at 600 and 640 nm (methylene blue), and at 530 nm (Janus red). Those of nuclei stained for DNA-aldehyde molecules are at 560 nm (Janus blue), at 600 and 630 nm (methylene blue), and at 520 nm (Janus red). Possible significance of these findings has been discussed.

Aldehydes↗
PubMed2000

Estimating the availability of polycyclic aromatic hydrocarbons for bioremediation of creosote contaminated soils.

Bioremediation of soil contaminated by organic compounds can remove the contaminants to a large extent, but residual contamination levels may remain which are not or only slowly biodegraded. Residual levels often exceed existing clean-up guidelines and thereby limit the use of bioremediation in site clean-up. A method for estimating the expected residual levels would be a useful tool in the assessment of the feasibility of bioremediation. In this study, three soil types from a creosote-contaminated field site, which had been subjected to 6 months of bioremediation in laboratory column studies, were used to characterize the residual contamination levels and assess their availability for biodegradation. The soils covered a wide range of organic carbon levels and particle size distributions. Results from the biodegradation studies were compared with desorption rate measurements and selective extractability using butanol. Residual levels of polycyclic aromatic hydrocarbons after bioremediation were found to be strongly dependent on soil type. The presence of both soil organic matter and asphaltic compounds in the soil was found to be associated with higher residual levels. Good agreement was found between the biodegradable fraction and the rapidly desorbable fraction in two of the three soils studied. Butanol extraction was found to be a useful method for roughly estimating the biodegradable fraction in the soil samples. The results indicate that both desorption and selective extraction measurements could aid the assessment of the feasibility for bioremediation and identifying acceptable end-points.

Biodegradation, Environmental↗
PubMed2004

Parameters affecting extraction of selected fungicides from vineyard soils.

This paper describes a sensitive method for the simultaneous quantification of eight commonly used grapevine fungicides in vineyard soils: cyprodinil, fludioxonil, metalaxyl, penconazole, pyrimethanil, procymidone, tebuconazole, and vinclozolin. The fungicides are extracted from the soil sample by sonication with water followed by shaking with ethyl acetate and are quantified by gas chromatography with mass spectrometry. Average extraction efficiencies in a sample of seven spiked, previously fungicide-free soils were > or =79% for all of the analytes, method precisions were > or =17%, and quantification limits were < or =50 microg/kg. However, because recoveries varied considerably from soil to soil, there is a need to control for soil matrix differences (mainly soil pH and exchangeable calcium content); as a consequence, soil fungicide contents must be quantified by the standard additions method. When the method was applied in this way to soil samples from vineyards belonging to the specified wine-growing region of Rias Baixas (Galicia, northwestern Spain) taken at the beginning of October (1 month after the crop's final treatment), levels of fludioxonil as high as 991 microg/kg were found, but at the start of the season (9 months after the previous crop's final treatment) only fludioxonil was detected at levels higher than its limit of quantification (45 and 52 microg/kg).

Dioxoles↗
PubMed1991

Study of the calcification of bovine pericardium: analysis of the implication of lipids and proteoglycans.

A major problem with cardiac bioprosthesis is the calcification of the tissue used in their manufacture, an event which may be promoted by multiple factors. A subcutaneously implanted model was used to determine, by selective extractions of proteoglycans and lipids, the role played by these compounds in the calcification of the bovine pericardial tissue used in the construction of some biological valves. The selective extraction of proteoglycans resulted in a great accumulation of calcium salts in the tissue, which, moreover, had a reduced hydrothermal stability. On the other hand, lipid extraction produced no modification in the stability of the tissue and resulted in a lesser calcium accumulation than in the control group. Proteoglycans and lipids may, therefore, be implicated in mineralization of the pericardial tissue.

Animals↗
PubMed1987

Direct determination of angiotensin-converting enzyme inhibitors in plasma by radioenzymatic assay.

We describe a simple, rapid, specific radioenzymatic assay for "CGS 16617," a new, potent inhibitor of angiotensin-converting enzyme (ACE; EC 3.4.15.1) in human plasma. This assay is based on the principle that the inhibitor (i.e., the drug) binds to the ACE in plasma and hence the amount of free ACE in plasma is inversely related to the amount of active inhibitor present. Free enzyme is reacted with a radiolabeled substrate, and the radioactive product is selectively extracted into the scintillation cocktail for quantification. Fivefold-diluted plasma samples are incubated with [3H]hippuryl-glycyl-glycine enzyme substrate at 37 degrees C for 30 min and the liberated [3H]hippuric acid is selectively extracted into scintillation cocktail. The radioactivity is counted in a liquid scintillation counter. Both within-run and between-run, the variability (CV) of the assay is less than 10%. As little as 200 ng of the drug per liter can be quantified in 50-microL plasma samples. The method can also be used to assay two other ACE inhibitors, pentopril and CGS 14831, demonstrating that the method can be readily adapted to any ACE inhibitor having a single active component in plasma. The ester prodrug pentopril can also be assayed after ester hydrolysis. This method is suitable for analysis of large numbers of samples in clinical laboratories for routine monitoring of the concentrations of active ACE inhibitors in blood.

Angiotensin-Converting Enzyme Inhibitors↗