Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “selective extraction”

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 1,333 records · Page 74Linked to original sources
PubMed2005

[Antioxidative activity of some over-the-counter plant extracts].

The recent years again saw increased interest of the public in the use of traditional natural remedies, such as plant extracts, for the treatment and prevention of diseases. This paper evaluates the antioxidative activity and content of phenolic substances of selected plant extracts from medicinal herbs, sold as dietary supplements with therapeutic effects. Using the production of 3-nitrotyrosine as the marker, the effects of extracts on the inhibition of peroxynitrite-induced nitration of tyrosine was examined, and the results were compared with the ability to extinguish the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). A linear correlation (r = 0.929) was found between the ability to extinguish DPPH and to inhibit tyrosine nitration. The found antioxidative activity ranged between values of 0-1702, or 0-1482 micromol of the catechine equivalent/100 ml of the extract. The total content of phenolic substances oscillated within values of 9.4-268.3 mg of the equivalent of gallic acid/100 ml of the extract. The significant linear relationship between antioxidative activities (r>0.9) and the total content of phenolic substances shows that phenolic substances are the principal group responsible for the antioxidative activity of the extracts tested.

Antioxidants↗
PubMed1991

Regulation of topoisomerase I and II activities by cyclic nucleotide- and phospholipid-dependent protein kinases. Effects of interactions between the two transduction pathways.

Incubation of cultured rat aortic smooth muscle cells (A-10) with activators of cyclic nucleotides resulted in transiently increased activity of extractable topoisomerase I or topoisomerase II. ANF, which induces cGMP accumulation, potentiated camptothecin-induced, topoisomerase I linked DNA strand breakage and increased the specific activity of extractable topoisomerase I (maximum activity 5-15 min after treatment), but had no effect on topoisomerase II activity. These effects are similar to those reported for AVP and phorbol esters, activators of protein kinase C. Forskolin and isoproterenol, which induce cAMP accumulation, activated extractable topoisomerase II (maximum 5-15 min after treatment), but not topoisomerase I. Permeable cyclic nucleotide analogs dBcAMP and 8BrcGMP selectively activated extractable topoisomerase II and topoisomerase I activities, respectively. Activation of topoisomerase I by either AVP or PdBu was attenuated by cotreatment with 8BrcGMP or dBcAMP, and activation of topoisomerase II by dBcAMP was attenuated by cotreatment with AVP or PdBU, suggesting that elements of the protein kinase C and the cyclic nucleotide linked signal-transduction pathways can interact to modify nuclear enzymic activity. IBMX, which elevates intracellular cAMP and cGMP, increased the extractable activities of both topoisomerase I and topoisomerase II. Thus, topoisomerase activity in cells may be governed in part by cyclic nucleotide levels.

Animals↗
PubMed1987

Coffee extracts inhibit platelet aggregation in vivo and in vitro.

The effect of aqueous coffee extracts on platelet aggregation in humans (in vitro) and rabbits (both in vitro and in vivo) was investigated. Coffee extracts were found to have anti-aggregatory effects on in vitro platelet aggregation induced by ADP or arachidonate but not by collagen. Coffee extracts were also effective after intravenous administration in rabbits. The compound(s) responsible for these effects are water-soluble, heat-resistant, appeared to be different from salicylates, and might also be due to unidentified compounds besides nicotinic acid or known xanthines. Coffee extract and selected fractions decreased the conversion of [14C]-arachidonic acid to thromboxane B2 by the platelets. These studies show that coffee extracts contain compounds which are active in inhibiting platelet aggregation, a critical step involved in thrombosis and other vascular disorders.

Adenosine Diphosphate↗
PubMed1999

Etiology of trachoma: a great success in isolating and cultivating Chlamydia trachomatis.

PURPOSE: To review the studies on the etiology of trachoma and to honor Professor Tang Feifan (Prof. FF Tang). He is the first scientist who was successful in isolating and cultivating chlamydia trachomatis in 1946. DATA SOURCES: The principal literatures are cited from Tang's papers published from the 1930s to the 1950s. Earlier literatures concerning early hypotheses for trachoma pathogenic agent are also studied. STUDY SELECTION AND DATA EXTRACTION: Only important and conclusive breakthroughs in Tang's papers are selected and extracted. RESULTS AND CONCLUSIONS: In the 1930s Tang was intending to repeat Noguchi's experiments in isolating bacterium granulosis from cases of trachoma in China and to employ bacterium granulosis isolated by Noguchi in 1928 for reproducing experimental trachomatous human clinical manifestations in China. Both experiments showed negative results. In the 1950s, before isolated chlamydia trachomtas, Tang and his colleagues had finished two fundamental studies: (1) the histological nature of trachoma, their relationship to etiological agent as well as to the host cells; and (2) the clinical manifestations and the morphological pictures of trachoma in monkeys. Eventually chlamydia trachomatis was isolated successfully and cultivated continuously.

Bacteriology↗
PubMed1995

Evidence for the presence of a non-catecholamine, clonidine-displacing substance in crude, methanolic extracts of bovine brain and lung.

In the present study we have prepared crude, methanolic extracts of bovine lung and bovine brain and, using radioligand binding assays in conjunction with a number of simple chromatographic techniques, provided evidence for the presence of a non-catecholamine 'clonidine-displacing substance' (CDS). The level of CDS in lung extracts (9 units/g wet weight n = 11) is approximately 3 times that in the brain extracts. Furthermore, the effect of the crude, methanolic extracts are selective for non-adrenoceptor, imidazoline (labelled by [3H]-idazoxan) and alpha 2-adrenoceptor binding sites (labelled by [3H]-clonidine); both extracts are 5-10-fold more potent displacers of ligand binding to alpha 2-adrenoceptors compared with binding to opiate receptors (labelled by [3H]-etorphine) and practically inactive against alpha 1-adrenoceptor and muscarinic binding sites (labelled by [3H]-prazosin and [3H]-quinuclidinyl benzilate, respectively). With the exception of the non-adrenoceptor, imidazoline binding assay, which used rat kidney membranes labelled by [3H]-idazoxan in the presence of the alpha 2-adrenoceptor antagonist RS-15385-197, all radioreceptor assays involved bovine cerebral cortex membranes. Although the extracts contain catecholamines (brain only), histamine (lung only) and monovalent cations (both), which have the potential to interfere with the radioligand binding assays, their concentrations were too low to account for the effects observed. Preliminary attempts at purification of the extracts revealed that CDS activities from the two tissues are similar, i.e., practically insoluble in organic solvents at room temperature, not affected by either Sep-Pak C18 column or anion exchange resins but retained (along with the monovalent cations) by cation exchange resin. However, following chromatographic separation on a Biogel P2 column, the CDS-containing eluates are cation-free and exhibit qualitatively similar elution profiles. Future experiments will involve further purification of 'clonidine-displacing substance' to characterize its interaction with alpha 2-adrenoceptor binding sites in greater detail and establish whether it has biological activity consistent with the properties implied by its effects in radioligand binding assays.

Animals↗
PubMed2002

Tornado extraction: a method to enrich and purify RNA from the nephrogenic zone of the neonatal rat kidney.

BACKGROUND: Development of the kidney is a complicated and tightly regulated process. Although several genes responsible for the renal development have been identified to date, the precise mechanisms of spatial and temporal regulation remain to be elucidated. Therefore, expanding our knowledge of molecules that are associated with nephrogenesis will be helpful to understand the whole process. METHODS: To extract RNA selectively from the nephrogenic zone of the developing kidney, we developed a simple and reliable method. RESULTS: This method, named "tornado extraction," enriched RNA of the nephrogenic zone by about 30-fold. In combination with the suppression subtractive hybridization, a considerable number of genes that were differentially expressed in the nephrogenic zone were obtained. These genes included a series of endodermal markers such as albumin and alpha-fetoprotein as well as GDNF (glia-derived neurotrophic factor), osteoblast-specific factor-2 (OSF-2)/periostin and fetuin (one of the major serum proteins in the fetus). CONCLUSION: Tornado extraction has great value in studying genes in the nephrogenic zone of the developing kidney. Since the quality of RNA obtained by this method is excellent, tornado extraction is suitable in combination with other techniques including the subtractive hybridization method and DNA microarray analysis.

Animals↗
PubMed1993

Paroxetine: a selective serotonin reuptake inhibiting antidepressant.

OBJECTIVE: To review the pharmacology, pharmacokinetics, clinical investigations, adverse effects, and dosing strategies of paroxetine as a treatment of major depression. DATA SOURCES: Specific paroxetine information was selected from a MEDLINE search using paroxetine as the search term. Other sources included manual searches of pertinent journal article references, meeting abstracts, and the manufacturer. STUDY SELECTION: Clinical investigations with a blind, controlled (placebo and/or active), randomized design were selected. With the exception of treatment-resistant depression, no short-term, open investigations were selected. DATA EXTRACTION: Clinical investigations were evaluated for design, sample size, diagnosis, duration, definition of response, and outcome. Data from all investigations were selected by one author and reviewed by both authors. DATA SYNTHESIS: Paroxetine is a selective serotonin reuptake inhibitor (SSRI) recently approved for the treatment of major depression. It is a potent and selective inhibitor of serotonin reuptake and has weak or no activity on the other monoamines; it is also weakly anticholinergic. Although pharmacokinetic parameters are variable, paroxetine is generally well absorbed, highly protein bound, hepatically cleared, and has no active metabolites. Clinical investigations support paroxetine's effectiveness as an antidepressant in an outpatient population with moderately severe depression. Its effectiveness is superior to that of placebo and is comparable to that of active controls. The majority of investigations have been six weeks in duration. Additional data are required to support paroxetine's promise for longer treatment periods (i.e., > or = 1 y), in the elderly, and for treatment-resistant depression. Adverse effects appear to be similar to those caused by the other SSRIs; some of the most common are nausea, diarrhea, insomnia, dry mouth, and nervousness. Significant drug interactions may occur with the monoamine oxidase inhibitors, phenobarbital, and phenytoin. CONCLUSIONS: Paroxetine is safe and effective for treatment of outpatients with moderately severe depression. Further clinical data and experience are necessary to determine this agent's place in the long-term treatment of major depression.

Aged↗
PubMed2000

Use of solid-phase microextraction for the quantitative determination of herbicides in soil and water samples.

An in-depth study of SPME optimization and application has been made, considering not only aqueous (surface water and groundwater samples) but also the more complex soil samples. Seven herbicides widely used in the area of study have been selected including five triazine herbicides (atrazine, simazine, terbumeton, terbuthylazine, terbutryn), molinate, and bromacil. linearity range was between 0.1 and 10 ng/mL and the repeatability below 10% when applying the optimized SPME procedure to water samples. Reproducibility was found to be lower than 20% at the 1 ng/mL level, and the limits of determination in environmental water samples using GC/MS (SIM mode) were well below 0.1 ng/mL (values ranging from 10 to 60 ng/L). Extraction of selected herbicides from soil was carried out by microwave-assisted solvent extraction using methanol in screw-capped vials, leading to recoveries over 80% in spiked soil samples at the 5-200 ng/g level. SPME application over methanolic soil extracts required a 10-fold dilution with distilled water. The recommended procedure was found to be fully applicable for quantitative determination of selected herbicides in soils containing low organic matter content with coefficients of variation below or around 10% and limits of determination ranging from 1 to 10 ng/g. Both procedures were applied to real-world surface water and soil samples where several pesticides were detected including atrazine, simazine, terbuthylazine, and molinate.

Herbicides↗
PubMed1989

Species-specific shrimp allergens: RAST and RAST-inhibition studies.

Two edible shrimp species are widely available in Louisiana, Penaeus setifecus (white shrimp) and Penaeus aztecus (brown shrimp). Some sensitive individuals report only occasional allergic symptoms after shrimp ingestion, suggesting that there may be species-specific allergens. To investigate this possibility, we evaluated shrimp species-specific reactivity in 31 individuals with a history of immediate hypersensitivity reactions after shrimp ingestion with skin prick tests and RASTs with white and brown shrimp extracts. On selected individuals, RAST-inhibition studies were performed with white shrimp and/or brown shrimp-coupled disks, with white and/or brown shrimp extracts as inhibiting allergen. Positive skin tests to both types of extract were observed in 77% (23/30) of the subjects; one individual reacted to brown shrimp extract only. Elevated RASTs to both extracts were observed in 16/31 study participants; one subject reacted only to white shrimp extracts and two subjects to brown shrimp extract alone. Sera from two individuals tested by RAST inhibition recognized qualitatively different allergens in brown and white shrimp extracts, supporting the hypothesis that there are species-specific shrimp allergens. Species specificity is important because it may explain the intermittent symptoms of some study subjects. The percentage of shrimp-sensitive subjects testing positive by skin test and RAST can be increased by use of extracts from more than one species of shrimp.

Adult↗
PubMed2001

Use of a simulated gizzard to measure bioavailability of metals and other elements to waterfowl.

We used a simulated gizzard environment to examine the bioavailability of barium, cadmium, copper, lead and zinc to wild and sentinel mallards (Anas platyrhynchos) using a seasonally-flooded wetland. This impoundment was originally constructed as a containment area for dredged sediments which were contaminated through previous smelting operations. Extraction of elements from gizzard contents indicated that sentinel mallards experienced greater exposure to contaminants than their wild counterparts. Concentrations of the selected elements extracted from ingesta were lower than in seeds and sediments from the study site. Notable exceptions were barium and lead, which were not detected in seeds of some plant species, though they were present in the ingesta of one or more treatment groups. This technique may provide a more realistic means of estimating bioavailability and exposure than methods which measure total concentrations of elements in dietary components. The use of sentinel mallards may result in inflated estimates of risk to wild ducks using seasonally-available wetlands.

Animals↗
PubMed1998

Use of different concentrations of carbamide peroxide for bleaching teeth: an in vitro study.

OBJECTIVE: This in vitro study compared the shade changes in extracted teeth during 2 weeks' whitening with 5%, 10%, or 16% carbamide peroxide. METHOD AND MATERIALS: After color calibration, the sole examiner selected 110 extracted unrestored, noncarious teeth, shade A3 or darker on a value-oriented guide. The teeth were randomly distributed into equal color groups. The control group (11 teeth) was treated with 0.9% saline, while the experimental groups (33 teeth each) were treated with 5%, 10%, or 16% carbamide peroxide. The solutions remained on the teeth for 8 hours. The teeth and tray were rinsed with tap water for 2 minutes, then rehydrated in 0.9% saline for 16 hours in the humidifier. The shade was assessed, and the process was repeated daily for 2 weeks. RESULTS: Repeated-measures analysis of variance indicated a significant difference in overall shade values between the control and all carbamide peroxide-treated groups at days 8 and 15. A Kaplan-Meier Survival Analysis indicated a quicker two-tab color change for the 10% and 16% groups than the 5% group. However, continuation of the 5% treatment to 3 weeks resulted in shades that approached the 2-week 10% and 16% values. CONCLUSION: Lower concentrations of carbamide peroxide take longer to whitening teeth but eventually achieve the same result as higher concentrations. Higher concentrations may cause increased sensitivity.

Analysis of Variance↗
PubMed2001

Evaluation of spore extraction and purification methods for selective recovery of viable Bacillus anthracis spores.

AIMS: To investigate methods of improving anthrax spore detection with PLET. METHODS AND RESULTS: Comparisons were made of PLET and blood-supplemented PLET to recover and distinguish spores of a variety of Bacillus species. Heat and ethanol purification of spores, and spore extraction from soil with water and high specific gravity sucrose plus non-ionic detergent, were also carried out. CONCLUSION: PLET was more selective and suitable than blood-supplemented PLET for detection of anthrax spores in the environmental specimens. However, PLET is not an optimal spore recovery medium. Purification of spores with ethanol was as effective as heat purification. High specific gravity sucrose plus detergent extraction solutions may be more sensitive than extraction with water. SIGNIFICANCE AND IMPACT OF THE STUDY: This study highlights shortcomings with the standard PLET isolation of anthrax spores and describes ways in which the procedure may be improved.

Bacillus anthracis↗
PubMed2000

Selective activation of pre-replication complexes in vitro at specific sites in mammalian nuclei.

As the first step in determining whether or not pre-replication complexes are assembled at specific sites along mammalian chromosomes, nuclei from G(1)-phase hamster cells were incubated briefly in Xenopus egg extract in order to initiate DNA replication. Most of the nascent DNA consisted of RNA-primed DNA chains 0.5 to 2 kb in length, and its origins in the DHFR gene region were mapped using both the early labeled fragment assay and the nascent strand abundance assay. The results revealed three important features of mammalian replication origins. First, Xenopus egg extract can selectively activate the same origins of bi-directional replication (e.g. ori-beta) and (beta') that are used by hamster cells in vivo. Previous reports of a broad peak of nascent DNA centered at ori-(beta/(beta)' appeared to result from the use of aphidicolin to synchronize nuclei and from prolonged exposure of nuclei to egg extracts. Second, these sites were not present until late G(1)-phase of the cell division cycle, and their appearance did not depend on the presence of Xenopus Orc proteins. Therefore, hamster pre-replication complexes appear to be assembled at specific chromosomal sites during G(1)-phase. Third, selective activation of ori-(beta) in late G(1)-nuclei depended on the ratio of Xenopus egg extract to nuclei, revealing that epigenetic parameters such as the ratio of initiation factors to DNA substrate could determine the number of origins activated.

Animals↗
PubMed1991

Extraction, orthodontic treatment, and craniomandibular dysfunction.

Signs and symptoms attributed to craniomandibular dysfunction (CMD) were registered in the Groningen longitudinal prospective study over a 15-year period. It is concluded that none of the three treatment types--removable appliances, Begg mechanics, and chin cups--should be considered causal factors for the signs and symptoms registered many years later. Furthermore, a comparison was made among nonextraction, extraction of all first premolars, and extraction of other teeth with regard to CMD and it was concluded that the original growth pattern that caused the teeth to be selected for extraction--rather than the extraction itself--is the most likely factor responsible for the frequency of CMD reported years later. This conclusion agrees with one based on a previously postulated idea about the relationship between dysfunction symptoms and growth patterns.

Adolescent↗
PubMed2006

The effects of mental practice in stroke rehabilitation: a systematic review.

OBJECTIVE: To assess the effects of a mental practice intervention on recovery in stroke patients. DATA SOURCES: A systematic literature search of the Cochrane Database of Systematic Reviews, PubMed/Medline, PsycINFO, Pedro, Rehadat, and RehabTrials was performed by 2 researchers independently. Eligible studies published through August 2005 were selected. STUDY SELECTION: Four randomized controlled trials (RCTs), 1 controlled clinical trial (CCT), 2 patient series, and 3 case reports that investigated the effects of a mental practice intervention on recovery of stroke patients were included. DATA EXTRACTION: The selected RCTs and CCT were assessed on a methodologic quality rating scale. Important characteristics and outcomes were extracted and summarized. Results and characteristics from the patient series and case reports were only provided if they added information. DATA SYNTHESIS: Included studies differed clearly from one another with regard to patient characteristics, intervention protocol, and outcome measures. Four different mental practice strategies were used. Most tasks involved mentally rehearsing movements of the arm. Intervention periods varied from 2 to 6 weeks, frequencies ranged from multiple sessions per day to 3 times a week. Studies were limited in size. Power could not be increased by pooling or meta-analysis because studies were not comparable. Three of the 4 RCTs were of reasonable methodologic quality. There was some evidence that mental practice as an additional therapy intervention had positive effects on recovery of arm function after stroke. Two mental practice techniques appeared to be effective-tape instruction and self-regulation. Results from the single case studies indicate that mental practice is also promising for improvement of leg function. CONCLUSIONS: No definite conclusions could be drawn except that further research, using clear definitions of the content of mental practice and standardized measurement of outcome, are needed.

Activities of Daily Living↗
PubMed2006

Selective inhibition of COX-2 by a standardized CO2 extract of Humulus lupulus in vitro and its activity in a mouse model of zymosan-induced arthritis.

A standardized CO(2) extract from Humulus lupulus L. (hop extract) was investigated for its selective COX-1/2 inhibitory properties. An in vitro model of inflammation using lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells (PBMC) was used as a model to investigate the effect of hop extract on PGE(2) production. COX-1/2 selective inhibition by the hop extract was investigated in a COX-1 whole blood assay (WBA) and a COX-2 WBA. To evaluate the in vivo activity of hop extract, it was administered orally to C57BL/6 mice in which inflammation of the right joint was induced by injecting zymosan intra-articularly. Ex vivo PGE(2) production of LPS-stimulated blood cells was determined. Also, the effect of hop extract on healthy and arthritic cartilage was investigated as well as effects on inflammatory joint swelling. Hop extract inhibited PGE(2) production by LPS-stimulated PBMC without compromising the metabolic activity of these cells. Furthermore, hop extract showed a decline in PGE(2) production in the COX-2 whole blood assay (WBA) with an IC(50) of 20.4 microg/mL, while in the COX-1 WBA no inhibition of PGE(2) production was observed. This indicates a COX-2 selective inhibition. The COX-1 inhibitor SC-560 inhibited PGE(2) production in the COX-1 WBA but not in the COX-2 WBA. At 2 microM, celecoxib inhibited PGE(2) production in the COX-2 WBA by 92 % and in the COX-1 WBA by 50 %. When hop extract was administered orally to C57BL/6 mice in which joint inflammation was induced with zymosan, PGE(2) production in ex vivo LPS-stimulated whole blood was significantly decreased by 24 %, suggesting that hop extract becomes bioavailable. Furthermore, oral administration of hop extract showed no negative or positive effects on healthy cartilage proteoglycan synthesis, or on zymosan-induced arthritic cartilage proteoglycan synthesis. However, no effect of oral administration of 1.25 mg hop extract daily was observed on joint swelling. In conclusion, this standardized CO(2) extract of Humulus lupulus could be a useful agent for intervention strategies targeting inflammatory disorders and/or inflammatory pain.

Administration, Oral↗
PubMed1996

The role of extraction in stability of orthodontic treatment.

Long-term postretention assessment of orthodontically treated cases has been of interest for 5 decades; however, extraction versus nonextraction follow-up studies are difficult to compare without regard to sample structure, therapy concept und different parameters. The results of selected studies- extraction of 1 or 2 incisors, of premolars and of second and third molars, early and late extraction therapy and serial extraction-showed that long-term postretention stability is not a realistic treatment goal. The Cologne long-term records allow optimistic prediction: relative stability has been found in the majority of former patients, irrespective of the kind of treatment and treatment time. Original anomaly, type (extraction/nonextraction) and amount of treatment, and end-of-treatment alignment were found to be major factors influencing dentoalveolar and skeletal post-treatment changes. The conclusion is that therapy-induced post-treatment changes can be reduced by having a treatment goal within the anatomic limits.

Bicuspid↗
PubMed2006

Optimization of native agar extraction from Hydropuntia cornea from Yucatán, México.

Response surface methodology (RSM) was used to determine optimum extraction conditions for yield, gelling temperature, melting temperature and apparent viscosity of native agar from the red alga Hydropuntia cornea. Two independent variables were selected during extraction, temperature (80, 90 and 100 degrees C) and time (2, 3 and 4 h). The extraction procedure using 100 degrees C and 3 h produced the greatest yield (43.3%), the greatest gelling temperature (32 degrees C) and the greatest melting temperature (78 degrees C). The extraction using 65 degrees C and 4 h produced the optimum statistical apparent viscosity (80.73 cPs), though agar yield under these conditions had low quality for industrial purposes. Temperature and time do not affect melting temperature, but do play an important role in gelling temperature. From the independent variables studied, extraction temperature is most important in producing an increase in yield, and time is the only variable that contributes significantly to increasing viscosity. Most of the physicochemical properties found in the native agar from H. cornea extracted at 100 degrees C/3 h were similar to commercial samples. These findings suggest the feasibility of using this colloid in spreads and soft-texture food products.

Agar↗