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PubMed1985

Chiral discrimination of 5,6-epoxy-3-dehydroretinal by aporetinochrome and cattle opsin.

The combination of a racemic all-trans 5,6-epoxy-3-dehydroretinal (EDR) with aporetinochrome formed a mixture of two diastereomeric pigments. One of the diastereomeric pigments which contained the all-trans EDR with a negative circular dichroic (CD) band, hereafter called EDR(-)-chrome, has its visible absorption maximum around 438 nm, while the other pigment, called EDR(+)-chrome, has its maximum at 464 nm. These were substantiated by measuring the optical activities of the two EDR isomers which were extracted from a mixture of racemic all-trans EDR and a smaller amount of aporetinochrome following exposure to orange light (greater than 530 nm) that irradiates EDR(+)-chrome selectively. The extracted all-trans EDR had a negative CD band around 240 nm and the extracted 11-cis EDR had a positive band in that region with two negative bands on either side of the main band. In the case of both pigments, the effect of alkalinization on the increase of absorbance in the near-ultraviolet and the decrease of absorbance in the visible region was proportionate, qualitatively, to that on the positive CD intensities in both regions. These results suggest that the chromophore EDR in each pigment binds to the same binding site via a Schiff base. The EDR(+)-chrome exhibited properties similar to those of retinochrome, but EDR(-)-chrome showed some different properties, i.e. its formation rate was slower than that of the former one and its absorption band in the near-ultraviolet appeared even at neutral pH. Moreover, by exposing EDR(-)-chrome to yellow light (greater than 480 nm), only a part of its prosthetic all-trans EDR was isomerized and resulted in the formation of 11-cis and 13-cis isomers. This variation in photoisomerizing activity was supposed to be due to the difference in conformation of the side chain between EDR(+) and EDR(-) in aporetinochrome. Combination of 11-cis EDR with cattle opsin was also shown to result in the formation of two diastereomeric pigments. The absorption maxima of the diastereomers containing 11-cis EDR(+) and EDR(-) were at about 446 and 474 nm, respectively.

Animals↗
PubMed1996

Anticoagulation with warfarin in infants and children.

OBJECTIVE: To provide a comprehensive review of warfarin use in infants and children, including recommendations for appropriate dosage and monitoring parameters. DATA SOURCES: A MEDLINE search (1966-1995) was used to identify pertinent English-language articles in the medical literature. The key search term was warfarin. Additional material was obtained from references cited in articles retrieved through MEDLINE. STUDY SELECTION: All articles involving children younger than 18 years were evaluated. In addition, articles on the pharmacokinetics and pharmacodynamics in adults, adverse effects, and drug interactions were included. DATA EXTRACTION: Material selected for review included clinical trials, case reports, and surveys of practice. DATA SYNTHESIS: Warfarin has been used as prophylactic therapy in children with prosthetic cardiac valves as well as for prevention of thromboembolic complications associated with autoimmune disorders and protein C or protein S deficiency. Warfarin also has been used to prevent embolization in children with deep-vein thrombosis or clots in central venous catheters. According to the literature, an initial dosage of 0.1 mg/kg/d should provide anticoagulation without significant adverse effects. As in adults, dosing should be adjusted to achieve a target international normalized ratio (INR). Although the target range in children is not well established, INR values of 1.5-3 are recommended for most patients. Higher values have been used in children with prosthetic cardiac valves and hereditary clotting disorders. CONCLUSIONS: Due to its infrequent use, there is limited information on the effects of warfarin in children. Basic guidelines for initiating and monitoring warfarin were developed by using data gathered from clinical trials, retrospective reviews, case series, and surveys of practice.

Adult↗
PubMed2005

Expression of estrogen receptor alpha gene in breast cancer cells treated with transcription factor decoy is modulated by Bangladeshi natural plant extracts.

The aim of the present study was to determine whether the expression of the estrogen receptor alpha (ERalpha) gene may be a possible target for compounds present in plant extracts from Aegle marmelos and Emblica officinalis, used in traditional Asian medicine in the treatment of tissue inflammation and cancer. To this aim, we evaluated the potential of the selected plant extracts to affect proliferation and differentiation of ERalpha-negative MDA-MB-231 breast cancer cells, which become ERalpha positive after treatment with a decoy molecule against a regulatory region of the human ERalpha gene. All the plant extracts inhibited cell proliferation and showed no effect on ERalpha gene expression, but when they were added in combination with the decoy molecule, a modulatory effect was observed, depending on the extract employed. The extracts exhibiting the greatest effects were those obtained from Aegle marmelos. Gas-chromatography/mass-spectrometry (GC/ MS) analysis enabled us to identify lupeol, a known triterpenoid, as the major bioactive component of A. marmelos plant extracts. Similar to the Aegle marmelos extracts, lupeol was found to stimulate the decoy effect of RA4 DNA sequence, increasing at a high level ERa gene expression in MDA-MB-231 ERalpha-negative breast cancer cells, and also inhibited cell proliferation.

Breast Neoplasms↗
PubMed2003

Chromium availability in ultramafic soils from New Caledonia.

The sources and potential availability of chromium (Cr) on soils formed on ultramafic rocks were investigated with mineralogical studies and selective chemical extractions. Soil solutions were collected in the field (i) along a soil toposequence under natural vegetation with ceramic cups; (ii) under grass in a mandarin trees plantation with tension-free tube lysimeters. On selected soil solutions, the Cr(VI) was determined colorimetrically with the s-diphenylcarbazide method and total Cr by ICP-AES and speciation of Cr(VI) was performed with the MINEQL+ V 4.5 software. The main mineralogical sources of Cr were Cr-substituted goethite and chromite. Up to 90 mg kg(-1) of Cr was extracted by KH(2)PO(4), whereas KCl extractable Cr was very low, indicating that exchangeable Cr was mainly in the highly toxic Cr(VI) form in these soils. Under natural vegetation, the Cr concentrations in the soil solutions remained relatively low (<20 microg l(-1)) due to the high retention of the Cr(VI) anions by Fe-oxides. The Cr concentrations were larger in well aerated colluvial soils, where high levels of Mn-oxides are able to oxidize Cr(III) to Cr(VI), than in piedmont soil where the Mn-oxide content is lower, or in alluvial soils from the lowlands, where waterlogging occurs. Cr concentrations reached 700 microg l(-1) in the field that was fertilized with high amount of phosphorus, due to the exchange of Cr(VI) with phosphate. In such conditions, toxicity phenomena for crops can be expected.

Biological Availability↗
PubMed2006

Identification of enantioselective extractants for chiral separation of amines and aminoalcohols.

The major obstacle for the introduction of fractional reactive extraction as a chiral separation method in the chemical and pharmaceutical industries is the lack of versatile enantioselective extractants. Therefore, a rational approach is developed to transfer the extensive knowledge of chiral selectors reported in the literature on chiral recognition and other chiral separation techniques to extraction. Based on a similarity in separation mechanisms, it was expected that chiral selectors originating from a technique in which chiral recognition takes place in the liquid phase are most likely to function as enantioselective extractant. Using this approach, a selection of promising extractants was made from the literature and experimentally evaluated for the enantioseparation of aminoalcohols and amines. As a result, four enantioselective extractant systems, namely, dibutyl-L-tartrate with boric acid, N-(2-hydroxydodecyl)-L-hydroxyproline Cu(II) complex, N-dodecyl-L-hydroxyproline Cu(II) complex, and azophenolic crown ether, have been identified. The azophenolic crown ether system performed the best and demonstrated an enantioselectivity between 1.3-5.0 for five out of six test compounds. Identification of the enantioselective extractant systems was highly facilitated by the developed rational transfer approach that, although partially qualitative, appeared capable of reducing more than 50 encountered candidates to only three promising systems for further experimental evaluation. Therefore, it is expected that this approach can be successfully applied to identify enantioselective extractants for other classes of enantiomers as well.

Amines↗
PubMed1991

Influence of zinc on copper binding in tissue proteins of steers.

Two experiments were conducted with steers fed diets containing 270 ppm copper either with or without 2050 ppm zinc. Liver biopsies were taken from steers biweekly for 10 wk for analysis. The steers were then killed; tissues were removed, homogenized, and centrifuged, and the pellets were extracted with mercaptoethanol (BME), and selected cytosols and extracts were subjected to gel filtration (Sephadex G-75). Copper and zinc were determined on the BME extracts, pellets after extraction, cytosols, and gel-filtration fractions. Copper accumulated at about the same rate in BME extract and in the extracted pellet, with the smallest amount in the cytosol. In contrast, over 70% of the zinc was present in the hepatic cytosols. Gel filtration of BME extracts revealed the greatest amount of copper in a low-mol-wt (MW) peak in addition to three minor peaks of copper. Within the hepatic cytosols, the greatest amount of copper accumulated in proteins of MW greater than 75,000, the next greatest amount in 30,000-MW proteins, and the least amount with metallothionein (MT) of steers fed the diet with only copper added. In contrast, the greatest amount of copper was present with MT in hepatic cytosols of the steer fed a diet that included copper plus zinc. Hence the zinc status of steers influences the deposition of copper in the cytosolic proteins (as demonstrated by liver, kidney, and pancreas), but not in the intracellular fractions.

Animals↗
PubMed2006

Nano-structured lead dioxide as a novel stationary phase for solid-phase microextraction.

The first study on the high efficiency of nano-structured lead dioxide as a new fiber for solid-phase microextraction (SPME) purposes has been reported. The size of the PbO2 particles was in the range of 34-136 nm. Lead dioxide-based fibers were prepared via electrochemical deposition on a platinum wire. The extraction properties of the fiber to benzene, toluene, ethylbenzene, and xylenes (BTEX) were examined using headspace solid-phase microextraction (HS-SPME) mode coupled to gas chromatography-flame ionization detection (GC-FID). The results obtained proved the suitability of proposed fibers for the sampling of organic compounds from water. The extraction procedure was optimized by selecting the appropriate extraction parameters, including preparation conditions of coating, salt concentration, time and temperature of adsorption and desorption and stirring rate. The calibration graphs were linear in a concentration range of 0.1-100 microg l(-1) (R2 > 0.994) with detection limits below 0.012 microg l(-1) level. Single fiber repeatability and fiber-to-fiber reproducibility were less than 10.0 and 12.5%, respectively. The PbO2 coating was proved to be very stable at relatively high temperatures (up to 300 degrees C) with a high extraction capacity and long lifespan (more than 50 times). Higher chemical resistance and lower cost are among the advantages of PbO2 fibers over commercially available SPME fibers. Good recoveries (81-108%) were obtained when environmental samples were analyzed.

Adsorption↗
PubMed2002

[Inhaled nitric oxide in the peroperative period and recovery].

OBJECTIVE: To analyse the current knowledge concerning use of inhaled NO (iNO) in anaesthesia and intensive care. DATA SOURCE: References were obtained from Medline, recent review articles, the library of the department and personal files. STUDY SELECTION: All categories of articles on this topic have been selected. DATA EXTRACTION: Articles have been analysed for history, biochemistry, pharmacology, toxicity and clinical use of iNO. DATA SYNTHESIS: Nitric oxide (NO) is a potent endothelium-dependent vasodilator. Because of its selective action on pulmonary circulation and the lack of effect on the systemic circulation due to its inactivation by haemoglobin, iNO has been presented as a new therapeutic agent in most diseases with pulmonary hypertension. During heart transplantation or surgical correction of congenital heart disease, iNO decreases pulmonary hypertension and improves altered right ventricular function. Studies included however small numbers of patients. Preliminary pharmacological studies demonstrated that iNO was able to decrease pulmonary hypertension and improve systemic oxygenation in adult respiratory distress syndrome. To date, none of the three multicentric studies performed was able to show any significant effect on duration of mechanical ventilation, morbidity or mortality. Finally, the sole demonstrated indication for iNO which remains is the persistent pulmonary hypertension of the newborn. Two multicentric studies have evidenced an improvement in systemic oxygenation and a reduced need for extracorporeal membrane oxygenation. In these two studies global mortality was however unchanged. CONCLUSION: Persistent pulmonary hypertension is the sole demonstrated indication for iNO. Inhaled nitric oxide may be efficient in pulmonary hypertension, right ventricular dysfunction and severe hypoxemia. Inhaled nitric oxide must be considered as a rescue therapy or needs to be part of research protocols.

Administration, Inhalation↗
PubMed2004

Solvent extraction and stripping of silver ions in room-temperature ionic liquids containing calixarenes.

We found that a calix[4]arene-bearing pyridine is soluble in a typical room-temperature ionic liquid (RTIL), 1-alkyl-3-methylimidazolium hexafluorophosphate. Pyridinocalix[4]arene showed a high extraction ability and selectivity for silver ions. The extraction performance of the calix[4]arene was greatly enhanced by dissolution in RTILs compared to in chloroform. In a competitive extraction test using five different metal ions (Ag+, Cu2+, Zn2+, Co2+, Ni2+), only silver ions were transferred by the calix[4]arene from the aqueous feed phase into the RTILs, through a cation-exchange mechanism. The pyridinocalix[4]arene was found to form a stable 1:1 complex with silver ions, both by slope analysis and by Job's method. Since it is easy to strip silver ions from RTILs by controlling the aqueous-phase pH, the extraction performance of calix[4]arene in RTILs was maintained after five repeated uses.

Journal Article↗
PubMed1992

Enhanced degradation of collagen within apical vs. basal wall of ovulatory ovine follicle.

Electron microscopic examination of ovulatory ovine follicles indicated that dissolution of thecal collagen was enhanced along the follicular circumference adjacent to the ovarian serosa. Concentrations of hydroxyproline were correspondingly lower within apical than basal tissues. Collagenolytic activity of tissue homogenates and extracts was assessed by monitoring radioactive peptide release from cocultured collagen fibrils. Collagenase inhibitors were separated from enzyme by sequential extraction of follicular homogenates with detergent and heating. Enzymatic activities of homogenates and heat extracts of apical and basal tissues increased toward ovulation. A distinction between apex and base was not attributed to significant differences in homogenates; however, collagenolytic activity of heat extracts of apical tissue was selectively elevated (i.e., extraction was evidently required to effectively dissociate collagenase from thecal fibrils, making more enzyme available for substrate digestion). Activity of detergent extracts was restored by dithiothreitol and iodoacetamide (which inactivate tissue inhibitors of metalloproteinases), and collagenolysis induced by heat extracts was augmented by aminophenylmercuric acetate (a stimulator of latent collagenases). Nonetheless, variations between apex and base invoked by these compounds were relative. It therefore appears that active collagenase is more tightly bound within the extracellular matrix of the follicular apex than enzyme associated with basal tissue. This phenomenon might serve to preferentially favor enzymatic catabolism of collagen in that region, thereby dictating the ovarian site of follicular rupture.

Animals↗
PubMed2002

New and emerging therapies for sepsis.

OBJECTIVE: To review the recent advances related to the pathophysiology of sepsis and the rationale for recombinant human-activated protein C (drotrecogin alfa) and other antisepsis agents currently in Phase III trials. DATA SOURCES: A MEDLINE (1990-December 2001) search was performed to identify pertinent literature on the pathophysiology of sepsis and treatment strategies. The search was supplemented with AdisInsight (Adis International) using the search terms sepsis, severe sepsis, or septic shock combined with agents in Phase II or higher clinical development. Abstracts presented at infectious diseases and critical care meetings were also reviewed. STUDY SELECTION AND DATA EXTRACTION: Clinical efficacy studies were selected for drotrecogin alfa and other Phase III investigational agents. DATA SYNTHESIS: Our current understanding of the pathophysiology of sepsis underscores the contribution of increased coagulation and diminished fibrinolytic activity working in conjunction with an excessive and dysregulated inflammatory response. The loss of homeostatic balance among these systems results in a systemic inflammatory response with generalized coagulopathy, microvascular thrombosis, and, ultimately, acute organ failure and death. As a result of these advances, several compounds are now in various phases of development. A recombinant human form of endogenous activated protein C (drotrecogin alfa) was recently approved by the Food and Drug Administration for severe sepsis in adults who have a high risk of death. It possesses anticoagulant, profibrinolytic, and antiinflammatory properties. Other compounds currently in Phase III trials include tissue-factor pathway inhibitor, tumor-necrosis factor antibody fragment, platelet-activating factor acetylhydrolase, antithrombin III, and pyridoxylated hemoglobin polyoxyethylene. CONCLUSIONS: With the recent approval of drotrecogin alfa, there is renewed optimism that we can effectively reduce sepsis-associated mortality.

Adult↗
PubMed2005

[Applying grading methods of synthesizing multiple guidelines to optimizing extracting technology for Radix Panacis Quinquefolii].

OBJECTIVE: To optimize the best extracting procedure for Radix Panacis Quinquefolii. METHODS: (1) The optimum alcohol extracting procedure was selected with the content and extraction efficiency of ginsenoside Rg, Re, Rb, from Radix Panacis Quinquefolii by orthogonal test design and synthesizing multiple guidelines method. (2) The content of three ginsenoides Rg1, Re and Rb1 in Radix Panacis Quinquefolii was determined by gradient elution method in RP-HPLC. RESULTS: The optimum alcohol-extracting procedure was determined as 12 times of 70% alcohol refluxing and extracting 3 h for 2 times. CONCLUSIONS: The optimum extracting procedure can increase extraction efficiency of Radix Panacis Quinquefolii.

Chromatography, High Pressure Liquid↗
PubMed1989

Hereford cattle protected against Boophilus microplus with antigens purified by immunoaffinity chromatography from larval and adult ticks.

Tick larvae (Boophilus microplus) were extracted, fractionated by gel filtration and ion-exchange chromatography, and the fractions assayed by enzyme-linked immunosorbent assay (ELISA) against sera from cattle immunized and protected by antigens from the mid-gut of adult ticks. Unfractionated, whole larval extracts and selected reactive components were used to vaccinate cattle; they decreased the number of ticks dropped after challenge, but the effect of treatment was not significant. Antigens purified from crude larval extracts by affinity chromatography, using immunoglobulin ligands from an immune steer vaccinated with tick mid-gut antigens, also failed to protect cattle. However, tick extracts from both larval and adult ticks, which were first separated into membrane-associated and soluble fractions and then purified by exposure to the affinity ligands, protected cattle greater than 80% against subsequent challenge with ticks.

Animals↗
PubMed1980

Determination of nanogram amounts of the antiarrhythmic drug Org 6001 in biological fluids and tissues using selected ion monitoring.

An assay method has been developed to determine the free base of Org 6001 (3 alpha-amino-5 alpha-androstan-2 beta-ol-17-one . HCl) in biological samples. The assay procedure consists of protein denaturation, ethyl acetate extraction, derivatization with tert-butyldimethylchlorosilane in dimethylformamide followed by n-hexane extraction and selected ion monitoring using trideuterated Org 6001 as an internal standard. For quantitation, the signals were monitored corresponding to the masses of the [M - 57]+ ions of 2-O-tert-butyldimethylsilyl, N-formyl derivatives of Org 6001 and the internal standard at m/z 390 and m/z 393, respectively. The assay method was applied to plasma samples from the human and rat, and to rat tissues including the target organ, the heart. The relationship between the Org 6001 plasma level and clinical effect in the human, the distribution of Org 6001 in rat tissues, and the correlation between the plasma level and the amount of Org 6001 in total heart tissue of the rat were determined.

Androstanols↗
PubMed2004

Mercury fractionation in contaminated soils from the Idrija mercury mine region.

Mercury (Hg) fractionation was investigated in contaminated soil in the Idrija Hg-mine region, Slovenia. The main aim of this study was to test and apply sequential extraction and quantification of different Hg phases in order to estimate the mobility and potential bioavailability of Hg in contaminated soils. Separation of Hg phases was performed by means of a selective sequential extraction procedure complemented by volatilization of elemental mercury (Hg0). The influence of temperature, moisture and storage on Hg0 volatilization was also investigated. The total Hg concentrations varied between 8.4 and 415 mg kg(-1) and were up to 40-fold higher than the maximum permissible set by Slovenian legislation. Fractionation measurements indicated cinnabar as the predominant Hg fraction, followed by Hg0. Accumulation of cinnabar predominantly occurred in coarse grained flood plain sediments, where on average it constituted more than 80% of total Hg. In contrast non-cinnabar fractions were found to be enriched in areas where fine grained material was deposited, reaching up to 60% of total Hg. The strong positive correlation (R2 = 0.71-0.99) among non-cinnabar fractions suggested that these fractions predominantly control the mobility and potential bioavailability of Hg. Sample pretreatment before fractionation influenced the partition of Hg between different fractions, and therefore fractionation in fresh, nontreated samples is suggested. In addition, the specificity of the extraction steps needs further attention, as it was shown that some extraction steps, such as the organo-chelating Hg fraction, do not provide meaningful results. This further suggests that protocols for mercury fractionation need further harmonization in order to improve the comparability of the results and their use in risk assessment. Volatile mercury fluxes averaged between 0.04 and 6.5 ng g(-1) h(-1). Good agreement (R2 = 0.81-0.95) was found between the non-cinnabar fractions and evaporation of Hg0. Both the temperature and sample moisture had significant effects on mercury volatilization. The results in this study were obtained at 70 degrees C, which may be somewhat high, in particular for bacterial activity which may also play an important role in Hg volatilization. Therefore it is strongly suggested that further optimisation of the protocol to assess Hg volatilization from soil is required.

Chemical Fractionation↗
PubMed2002

The Eukaryotic Promoter Database, EPD: new entry types and links to gene expression data.

The Eukaryotic Promoter Database (EPD) is an annotated, non-redundant collection of eukaryotic Pol II promoters, for which the transcription start site has been determined experimentally. Access to promoter sequences is provided by pointers to positions in nucleotide sequence entries. The annotation part of an entry includes a description of the initiation site mapping data, exhaustive cross-references to the EMBL nucleotide sequence database, SWISS-PROT, TRANSFAC and other databases, as well as bibliographic references. EPD is structured in a way that facilitates dynamic extraction of biologically meaningful promoter subsets for comparative sequence analysis. World Wide Web-based interfaces have been developed which enable the user to view EPD entries in different formats, to select and extract promoter sequences according to a variety of criteria, and to navigate to related databases exploiting different cross-references. The EPD web site also features yearly updated base frequency matrices for major eukaryotic promoter elements. EPD can be accessed at http://www.epd.isb-sib.ch.

Animals↗
PubMed2001

Relevance of Cryptosporidium parvum hsp70 mRNA amplification as a tool to discriminate between viable and dead oocysts.

Two mRNA extraction methods were compared in this study to clarify the discrepancies found between authors regarding the presence of mRNA in inactivated Cryptosporidium parvum oocysts. Cryptosporidium parvum heat shock protein 70 (hsp70) mRNA extraction was performed by using oligo(dT)20-labeled magnetic beads or by incubating oocyst lysates with DNase I. Significant differences in mRNA recovery rates between these 2 techniques were observed when working on inactivated oocysts. We consistently detected hsp70 mRNA in oocysts heated at 60 C for 30 min and oocysts incubated in 10% formalin for 2 hr when using DNase I in the mRNA extraction procedure. In contrast, no mRNA was detected in such oocysts when magnetic beads were used for the mRNA extraction. The selective capture of long poly-A tail mRNA, when using oligo(dT)20-labeled magnetic beads, is proposed in this paper for explaining the discrepancies observed between the two mRNA extraction methods compared in this study. DNA decay in inactivated and aging oocysts makes quantitative polymerase chain reaction a potential alternative technique for assessing C. parvum oocyst viability status in environmental samples.

Animals↗