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 1,081 records · Page 60Linked to original sources
PubMed2000

An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures.

Serial dilutions of 21 commercial ethanolic herbal extracts and tinctures, and 13 related pure plant compounds have been analyzed for their in vitro cytochrome P450 3A4 (CYP3A4) inhibitory capability via a fluorometric microtitre plate assay. Roughly 75% of the commercial products and 50% of the pure compounds showed significant inhibition of CYP3A4 metabolite formation. For each herbal product and pure compound exhibiting dose-dependency, the inhibition values were used to generate median inhibitory concentration (IC50) curves using linear regression. Among the commercial extracts, Hydrastis canadensis (goldenseal), Hypericum perforatum (St. John's wort), and Uncaria tomentosa (cat's claw) had the lowest IC50 values at < 1% full strength, followed by Echinacea angustifolia roots, Trifolium pratense (wild cherry), Matricaria chamomilla (chamomile), and Glycyrrhiza glabra (licorice), which had IC50 values ranging from 1%-2% of full strength. Dillapiol, hypericin, and naringenin had the lowest IC50 values among the pure plant compounds at < 0.5 mM; dillapiol was the most potent inhibitor at 23.3 times the concentration of the positive CYP3A4 inhibitor ketoconazole. Utilizing high-throughput screening methodologies for assessing CYP3A4 inhibition by natural products has important implications for predicting the likelihood of potential herbal-drug interactions, as well as determining candidates for further in-depth analyses.

Cytochrome P-450 CYP3A↗
PubMed2004

Extraction of cesium ions from aqueous solutions using calix[4]arene-bis(tert-octylbenzo-crown-6) in ionic liquids.

Solvent extraction of cesium ions from aqueous solution to hydrophobic ionic liquids without the introduction of an organophilic anion in the aqueous phase was demonstrated using calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) as an extractant. The selectivity of this extraction process toward cesium ions and the use of a sacrificial cation exchanger (NaBPh(4)) to control loss of imidazolium cation to the aqueous solutions by ion exchange have been investigated.

Journal Article↗
PubMedDate not supplied

Solvent selection strategies for extractive biocatalysis.

This report follows the development of systematic solvent screening strategies for the identification of superior pure solvents and introduces techniques for the identification of effective coextractants. Specifically, methods to predict the biocompatibility and extractant capability of solvents are discussed. Biocompatibility is predicted by using heuristic data or the correlations between bioactivity and the logarithm of the partition coefficient of the solvent or the concentration of solvent in the cell membrane. A computer program, known as the extractant screening program or ESP, has been developed to effectively predict the behavior of virtually any product in any solvent/aqueous system. It is demonstrated that a biocompatible yet poor solvent can be mixed with a toxic solvent that has better extractant properties to yield a mixture with improved solvent characteristics that is still biocompatible. The fact that solvents do not mix in an ideal manner is exploited by using ESP to identify solvent mixtures that are still biocompatible at relatively high concentrations of toxic solvent.

Animals↗
PubMed2003

Evidence for very tight sequestration of BTEX compounds in manufactured gas plant soils based on selective supercritical fluid extraction and soil/water partitioning.

Benzene, toluene, ethylbenzene, o-, m-, and p-xylenes (BTEX), and polycyclic aromatic hydrocarbons (PAHs) were extracted from eight manufactured gas plant (MGP) soils from sites that had been abandoned for several decades. Supercritical fluid extraction (SFE) with pure carbon dioxide demonstrated the presence of BTEX compounds that were highly sequestered in both coal gas and oil gas MGP soils and soots. Benzene was generally the slowest compound to extract from all samples and was even more difficult to extract than most two- to five-ring PAHs found on the same samples. Since the solubility of benzene in carbon dioxide is 2-5 orders of magnitude higher than the solubilities of PAHs, these results demonstrate that benzene was more tightly sequestered than toluene, ethylbenzene, xylenes, or the multi-ring PAHs. Additional evidence for very tight binding was based on the fact that BTEX concentrations determined using either SFE or with methylene chloride sonication were much higher than those obtained by the U.S. EPA purge-and-trap method, especially for benzene (whose concentration was underestimated by as much as 1000-fold by the EPA method). However, soil/water desorption showed little benzene mobility, and Kd values for benzene were 1-2 orders of magnitude higher than those calculated based on literature sorption K(OC) values. These results indicate that environmentally relevant concentrations of benzene may be better represented by mild extraction methods than by methods capable of extracting tightly bound benzene.

Benzene↗
PubMed2004

Genetic predisposition to salt-sensitivity: a systematic review.

PURPOSE: To assess the role of genetic polymorphisms in salt sensitivity of blood pressure. DATA IDENTIFICATION: We conducted a systematic review by searching the Medline literature from March 1993 to June 2003. Each paper was scrutinized and data concerning study population, method of salt sensitivity testing, blood pressure measurement, definition of salt sensitivity, and effects were extracted. STUDY SELECTION AND DATA EXTRACTION: A total of 23 studies met the inclusion criteria. There was considerable heterogeneity in the method of salt sensitivity testing among the studies. Due to these differences, it was impossible to perform pooled analyses by genetic variants. Detailed investigation was done on the alpha-adducin Gly460Trp, ACE I/D, angiotensinogen M235T, G protein beta 3 C825T, aldosterone synthase gene and 11 beta-hydroxysteroid dehydrogenase type 2 G534A polymorphism. RESULTS AND CONCLUSIONS: Our analysis shows that the 460Trp variant of the alpha-adducin polymorphism is probably associated with a sodium-sensitive form of hypertension, while the polymorphisms of the angiotensin II type 1 receptor gene and the -344C/T variant of the aldosterone synthase gene are not associated with this phenotype. In view of the lack of standardization in salt sensitivity testing, we propose uniformity in study design in these type of studies.

Genetic Predisposition to Disease↗
PubMed1997

Tetanus: pathophysiology and management.

OBJECTIVE: To review the epidemiology, pathophysiology, clinical manifestations, diagnosis, and management of tetanus and its complications. DATA SOURCES: MEDLINE and Iowa Drug Information Services databases were searched for literature pertaining to tetanus. Additional literature was obtained from the references of selected articles identified in the search. Information from all articles was considered for inclusion in the manuscript. STUDY SELECTION AND DATA EXTRACTION: Articles selected were those considered by the authors to assist in providing the reader an understanding of the epidemiology, pathophysiology, clinical manifestations, diagnosis, and management of tetanus. DATA SYNTHESIS: While the number of tetanus cases has decreased markedly since data reporting for the disease began in 1947, mortality among those who acquire the disease remains high. Elderly patients are particularly susceptible to tetanus and its complications. Prevention of tetanus focuses on primary immunization and scheduled boosters. Management of tetanus involves initial stabilization of the patient and protection of the airway, prevention of tetanospasmin absorption by administration of human tetanus immune globulin 3000-6000 IU, and eradication of Clostridium tetani with antimicrobial therapy (metronidazole 500 mg q8h). Supportive measures include the administration of neuromuscular blocking agents such as pancuronium in patients requiring artificial ventilation, as well as benzodiazepines (midazolam 5-15 mg/h) for sedation and muscle relaxation. Autonomic dysfunction should be managed with beta-adrenergic blockers such as propranolol or labetalol. CONCLUSIONS: Despite the relative infrequency of tetanus cases, mortality among untreated patients remains significantly high. Clinicians should become knowledgeable in the pathophysiology, clinical manifestations, and management of this potentially fatal disease.

Humans↗
PubMed2006

Inhaled amphotericin B for prophylaxis against invasive Aspergillus infections.

OBJECTIVE: To evaluate the available literature describing the use of inhaled amphotericin B for prophylaxis of invasive Aspergillus spp. infections. DATA SOURCES: A MEDLINE search was conducted (1966-July 2006) using the key terms amphotericin B, inhaled amphotericin B, Aspergillus spp., invasive aspergillosis, solid-organ transplant, neutropenia, and inhalation. Review of the reference lists of the identified articles was also performed. STUDY SELECTION AND DATA EXTRACTION: Study selection included published trials, case reports, and case series of humans with hematologic disease and solid-organ transplant who used inhaled amphotericin B in the prevention of invasive Aspergillus infections. DATA SYNTHESIS: Inhaled amphotericin B has been evaluated for the prevention of invasive aspergillosis (IA) infections in neutropenic patients and certain solid-organ transplant recipients. Use of inhaled amphotericin B seems to reduce the incidence of IA in these patients; however, some of the clinical evidence was limited by factors such as small sample sizes, lack of statistical analyses, and lack of power to detect a difference between prophylaxis and control groups. Although the clinical evidence supporting the use of inhaled amphotericin B has some limitations, its use still may be beneficial for the prophylaxis of invasive Aspergillus infections, especially in solid-organ transplant recipients where the evidence is strongest. CONCLUSIONS: Invasive Aspergillus infections are becoming more prevalent in high-risk populations (eg, patients with malignancies, following bone marrow transplantation, or following solid-organ transplantation). The mortality rates associated with IA are great in these populations, making prophylaxis an important consideration. Inhaled amphotericin B has recently come into vogue as an option for prophylaxis against IA. Some of the data available supports the use of inhaled amphotericin B for the prevention of IA while providing evidence of fewer drug interactions and toxicities associated with other antifungal agents.

Administration, Inhalation↗
PubMed2001

What are appropriate rates of invasive procedures following acute myocardial infarction? A systematic review.

OBJECTIVE: To assess the evidence that higher rates of coronary angiography (CA) and revascularisation (RV) in the subacute phase of acute myocardial infarction (AMI) improve patient outcomes. DATA SOURCES: MEDLINE 1990 - December 1999, Current Contents 1990-1999, Cochrane Library (Issue 4, 1999), HealthSTAR 1990-1999, selected websites and bibliographies of retrieved articles. STUDY SELECTION AND DATA EXTRACTION: Studies selected were (1) randomised trials comparing outcomes of "invasive" versus "conservative" use of CA and RV following AMI; (2) observational studies with formal methods comparing outcomes of high versus low rates of use of these procedures; and (3) clinical practice guidelines (CPGs), expert panel statements and decision analyses which met critical appraisal criteria, and which specified procedural indications. Outcome measures were rates of mortality, re-infarction and limiting or unstable angina. DATA SYNTHESIS: 56 articles were identified; 24 met inclusion criteria. Pooled data from nine RCTs of "invasive" (CA rate 96%; RV rate 66%) versus "conservative" (CA rate 28%; RV rate 19%) strategies showed no significant differences in mortality or re-infarction rates. Pooled results from 12 observational studies showed no mortality differences, but an excess reinfarction rate (8.0% vs 6.4%; P<0.001) in high- versus low-rate populations. Evidence of survival benefit from procedural intervention was strongest for patients with recurrent ischaemia combined with left ventricular dysfunction. CONCLUSIONS: In the subacute phase of AMI, rates of CA and RV in excess of 30% and 20%, respectively, may not confer additional benefit in preventing death or re-infarction. However, variability between studies in design, patient selection, and extent of cross-over from medical to procedural groups, as well as limited data on symptom status, limits generalisability of results.

Angioplasty, Balloon, Coronary↗
PubMed1996

The variant forms of autoimmune hepatitis.

OBJECTIVES: To review the diagnostic criteria for autoimmune hepatitis, to characterize the variant forms of autoimmune hepatitis, and to indicate appropriate therapies for this condition. DATA SOURCES: A MEDLINE search (1990 to 1995) of the English-language literature, review of a personal library of journals and reprints (1975 to 1995), and review of references selected from the bibliographies of identified articles. Terms used in the MEDLINE search included the names of all autoimmune liver diseases, viral hepatitis and autoimmunity, cryptogenic hepatitis, and overlap syndromes. STUDY SELECTION: All articles that discussed atypical clinical features, mixed diagnostic findings, and variations in treatment response were selected. DATA EXTRACTION: Data were selected from 548 articles. DATA SYNTHESIS: Standardized criteria permit the confident diagnosis of autoimmune hepatitis, but they exclude many patients who have features suggesting autoimmunity. Such patients have findings indicative of both autoimmune hepatitis and another disorder (overlap syndromes) or findings that are inconsistent with the classic definition of autoimmune hepatitis (outlier syndromes). Overlap syndromes include combinations of autoimmune hepatitis and primary biliary cirrhosis, primary sclerosing cholangitis, or chronic viral hepatitis. Treatment of these syndromes requires identification of the predominant disorder and selection of the most appropriate drug regimen. Outlier syndromes include autoimmune cholangitis and cryptogenic chronic hepatitis. Corticosteroids or ursodeoxycholic acid are treatment options for patients with autoimmune cholangitis; corticosteroids can also benefit patients with cryptogenic chronic hepatitis. Grading each clinical feature and developing a composite score can permit comparison of the variants and a determination of the similarity between the variants and autoimmune hepatitis. CONCLUSIONS: Variant forms of autoimmune hepatitis are common. Recognition of them is important in assessing common pathogenic mechanisms, developing effective treatment strategies, and refining classification schemes.

Autoimmune Diseases↗
PubMed2001

[Selection of optimal extraction process for magnolol by orthogonal design].

To find out the optimal extraction process for magnoliae cortex, the extraction process was studied by orthogonal design with yield of the extracta sicca from magnoliae cortex and magnolol content as indexes. Four factors were chosen in this experiment, including alcohol consistence, the alcohol consumption, duration of extraction and times of extraction. The results showed that the optimal extraction process was 65% alcohol consumpted 8 times the amount of magnoliae cortex, refluxing for 3 times, each time 120 min.

Alcohols↗
PubMed2003

[Selection of optimal extraction process for huolisu capsule by orthogonal design].

OBJECTIVE: To find out the optimal extraction process for Huolisu capsule. METHOD: The extraction process was studied by orthogonal design with yield of the extracted ginsenoside Re and anthraquinone content determined by RP-HPLC as indexes. RESULT: The result showed that the optimal extraction process was 50% alcohol, 8 times the amount of herbs, refluxing for 2 times, each time 2 hours.

Analysis of Variance↗
PubMed2004

[Selection of an extraction agent and development of the technology for producing an extract with sedative effects].

The drugs Valerinae radix, Crataegi fructus, Leonuri herba and Melissae folium were used to produce a liquid plant extract. The experiment revealed that the extraction with 70% ethanol achieved the highest concentration of extractable active principles. The optimal conditions for obtaining a sedative extract are established when the method of repercolation is used, and in the production itself the batch of the drug is divided into equally large doses and a pre-prepared mixture of plant drugs is extracted. The extract prepared by this manner remains stable for the whole period of storage, i.e., 24 months.

Chemistry, Pharmaceutical↗
PubMedDate not supplied

Determination of multiclass pesticide residues in apple juice by gas chromatography-mass selective detection after extraction by matrix solid-phase dispersion.

A multiresidue method is described for the analysis of 106 multiclass pesticides (organochlorine, organophosphate, carbamate, pyrethroid, and triazine classes) in apple juice in a single injection. The determination procedure was based on matrix solid-phase dispersion of juice on diatomaceous earth in a glass column and subsequent extraction with a mixture of hexane-dichloromethane (1 + 1) at a flow rate of 5 mL/min. The analytes were determined by capillary gas chromatography with mass spectrometric detection and confirmed by their retention times and ion ratios. The coefficients of variation for analysis of samples fortified over the range of 0.01-0.2 mg/kg were 1.62 to 18.4%, and the recoveries for all analytes were between 70 and 110%.

Beverages↗
PubMed2004

[Observation of the change of blood pressure in 835 patients during extraction of teeth].

PURPOSE: To observe the change of blood pressure during extraction of teeth. METHODS: Patients without hypertension who needed extraction were randomly selected, tooth extraction was carried out. The blood pressure and the patient's response to operation were observed and recorded during the procedure. RESULTS: The blood pressure in 825 patients increased significantly. The average increased blood pressure was 45/26 mmHg, 3 patients had arrhythmia, 5 patients had adverse reaction. CONCLUSION: The patient's blood pressure must be fewer than 140/90 mmHg, before a difficult extraction of teeth.

Adult↗