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PubMed1997

Screening for colorectal cancer with the fecal occult blood test: a background paper. American College of Physicians.

PURPOSE: Screening for colorectal cancer with fecal occult blood tests or sigmoidoscopy can reduce mortality rates. If occult blood testing is done, clinicians must decide how to interpret the results and plan further management. If the results are positive, a decision must be made about evaluating the colon. This report provides information that can be used to perform fecal occult blood tests, interpret the results of those tests, and plan patient management. DATA SOURCES: The MEDLINE database was searched for data relevant to optimizing the technique of fecal occult blood testing. Studies were also identified from the bibliographies of published articles about test performance and the interpretation of test results, particularly sensitivity, specificity, and the probability of colorectal cancer after a positive test result. STUDY SELECTION AND DATA EXTRACTION: Studies were selected and data were extracted on the basis of the authors' combined judgment. DATA SYNTHESIS: When used for screening, fecal occult blood tests have positive results about 1% to 16% of the time, depending on such factors as the age of the person being tested, whether the sample is rehydrated, and whether the test is used for initial screening or for rescreening. When the colons of persons who have positive test results are evaluated, the rate of finding any colorectal cancer is about 2% to 17% and the rate for early colorectal cancer (Dukes stage A or B) is about 2% to 14%. CONCLUSIONS: These results suggest that, in general, persons who have positive results on a fecal occult blood test should have a full colonic examination. More research is needed to understand and improve the sensitivity and specificity of the fecal occult blood test.

Colorectal Neoplasms↗
PubMed1994

A selective procedure for DNA extraction from apoptotic cells applicable for gel electrophoresis and flow cytometry.

In cells undergoing apoptosis (programmed cell death), a fraction of nuclear DNA is fragmented to the size equivalent of DNA in mono- or oligonucleosomes. When such DNA is analyzed by agarose gel electrophoresis it generates the characteristic "ladder" pattern of discontinuous DNA fragments. Such a pattern of DNA degradation generally serves as a marker of the apoptotic mode of cell death. We developed a simple, rapid, and selective procedure for extraction of the degraded, low-molecular-weight DNA from apoptotic cells. The cells are prefixed in 70% ethanol, DNA is extracted with 0.2 M phosphate-citrate buffer at pH 7.8, and the extract is sequentially treated with RNase A and proteinase K and then subjected to electrophoresis. The ladder pattern was detected from DNA extracted from 1-2 x 10(6) HL-60 cells, of which as few as 8% were apoptotic, by flow cytometric criteria, as well as from blood and bone marrow samples from leukemic patients undergoing chemotherapy. The method is rapid and uses nontoxic reagents (no phenol, chloroform, etc.). This approach permits the analysis of DNA extracted from the very same cell population that is subjected to measurements by flow cytometry to estimate DNA ploidy, the cell cycle distribution of nonapoptotic cells, the percentage of apoptotic cells, or other parameters. Furthermore, the cells may be stored in 70% ethanol for at least several weeks before analysis without any significant DNA degradation. Treatment with ethanol also inactivates several pathogens, thereby increasing the safety of sample handling. The method is applicable to clinical samples, which can be fixed in ethanol and then stored and/or safety transported prior to analysis.

Apoptosis↗
PubMed2004

Separation, identification, and quantification of selected withanolides in plant extracts of Withania somnifera by HPLC-UV(DAD)--positive ion electrospray ionisation-mass spectrometry.

This paper describes a method for separation, identification, and quantification of selected withanolides in Withania somnifera plant extracts by HPLC-UV(DAD)-Mass Spectrometry (HPLC-MS). Withaferin-A (WS-3), 12-deoxywithastramonolide (WS-12DS), Withanolide A (WS-1), and Withanone (WS-2) were used as external standards. The compounds were isolated from Withania somnifera by repeated column chromatography of the root extract and their identity was established by 1H- and 13C-NMR and mass spectral data. The compounds were chromatographed on a Merck (250 x 4.6 mm ID, 5 microm) column and analyzed by Electrospray Ionization on a mass spectrometer in Selected Ion Mode (SIM). For quantification, [M + Na]+ ions were monitored. Linear calibration curves were obtained in the concentration range of 1.50 microg/mL to 6.5 microg/mL. The method was applied successfully to the detection and quantification of the said withanolides in a number of samples.

Chromatography, High Pressure Liquid↗
PubMed2002

Selective permeation and organic extraction of recombinant green fluorescent protein (gfpuv) from Escherichia coli.

BACKGROUND: Transformed cells of Escherichia coli DH5-alpha with pGFPuv, induced by IPTG (isopropyl-beta-d-thiogalactopyranoside), express the green fluorescent protein (gfpuv) during growth phases. E. coli subjected to the combination of selective permeation by freezing/thawing/sonication cycles followed by the three-phase partitioning extraction (TPP) method were compared to the direct application of TPP to the same culture of E. coli on releasing gfpuv from the over-expressing cells. MATERIAL AND METHODS: Cultures (37 degrees C/100 rpm/ 24 h; mu = 0.99 h(-1)-1.10 h(-1)) of transformed (pGFP) Escherichia coli DH5-alpha, expressing the green fluorescent protein (gfpuv, absorbance at 394 nm and emission at 509 nm) were sonicated in successive intervals of sonication (25 vibrations/pulse) to determine the maximum amount of gfpuv released from the cells. For selective permeation, the transformed previously frozen (-75 degrees C) cells were subjected to three freeze/thaw (-20 degrees C/ 0.83 degrees C/min) cycles interlaid by sonication (3 pulses/6 seconds/25 vibrations). The intracellular permeate with gfpuv in extraction buffer (TE) solution (25 mM Tris-HCl, pH 8.0, 1 mM beta-mercaptoethanol beta-ME, 0.1 mM PMSF) was subjected to the three-phase partitioning (TPP) method with t-butanol and 1.6 M ammonium sulfate. Sonication efficiency was verified on the application to the cells previously treated by the TPP method. The intra-cell releases were mixed and eluted through methyl HIC column with a buffer solution (10 mM Tris-HCl, 10 mM EDTA, pH 8.0). RESULTS: The sonication maximum released amount obtained from the cells was 327.67 microg gfpuv/mL (20.73 microg gfpuv/mg total proteins-BSA), after 9 min of treatment. Through the selective permeation by three repeated freezing/thawing/sonication cycles applied to the cells, a close content of 241.19 microg gfpuv/mL (29.74 microg gfpuv/mg BSA) was obtained. The specific mass range of gfpuv released from the same cultures, by the three-phase partitioning (TPP) method, in relation to total proteins, was higher, between 107.28 microg/mg and 135.10 microg/mg. CONCLUSIONS: The selective permeation of gfpuv by freezing/thawing/sonication followed by TPP separation method was equivalent to the amount of gfpuv extracted from the cells directly by TPP; although selective permeation extracts showed better elution through the HIC column.

Ammonium Sulfate↗
PubMed2005

An ion-imprinted functionalized silica gel sorbent prepared by a surface imprinting technique combined with a sol-gel process for selective solid-phase extraction of cadmium(II).

A new ion-imprinted thiol-functionalized silica gel sorbent was synthesized by a surface imprinting technique in combination with a sol-gel process for selective on-line, solid-phase extraction of Cd(II). The Cd(II)-imprinted thiol-functionalized silica sorbent was characterized by FT-IR, the static adsorption-desorption experiment, and the dynamic adsorption-desorption method. The maximum static adsorption capacity of the ion-imprinted functionalized sorbent was 284 micromol g(-1). The largest selectivity coefficient for Cd(II) in the presence of Pb(II) was over 220. The static uptake capacity and selectivity coefficient of the ion-imprinted functionalized sorbent are higher than those of the nonimprinted sorbent. The breakthrough capacity and dynamic capacity of the imprinted functionalized silica gel sorbent for 4 mg L(-1) of Cd(II) at 5.2 mL min(-1) of sample flow rate were 11.7 and 64.3 micromol g(-1), respectively. No remarkable effect of sample flow rate on the dynamic capacity was observed as the sample flow rate increased from 1.7 to 6.8 mL min(-1). The imprinted functionalized silica gel sorbent offered a fast kinetics for the adsorption and desorption of Cd(II). The prepared ion-imprinted functionalized sorbent was shown to be promising for on-line, solid-phase extraction coupled with flame atomic absorption spectrometry for the determination of trace cadmium in environmental and biological samples. All competitive ions studied did not interfere with the determination of Cd(II). With a sample loading flow rate of 8.8 mL min(-1) for 45-s preconcentration, an enhancement factor of 56, and a detection limit (3sigma) of 0.07 microg L(-1) were achieved at a sampling frequency of 55 h(-1). The precision (RSD) for 11 replicate on-line sorbent extractions of 8 mug L(-1) Cd(II) was 0.9%. The sorbent also offered good linearity (r = 0.9997) for on-line, solid-phase extraction of trace Cd(II).

Adsorption↗
PubMed2004

Selective solid-liquid extraction of lithium halide salts using a ditopic macrobicyclic receptor.

A ditopic salt receptor that is known to bind and extract solid NaCl, KCl, NaBr, and KBr into organic solution as their contact ion pairs is now shown by NMR and X-ray crystallography to bind and extract solid LiCl and LiBr as water-separated ion pairs. The receptor can transport these salts from an aqueous phase through a liquid organic membrane with a cation selectivity of K+ > Na+ > Li+. However, the selectivity order is strongly reversed when the receptor extracts solid alkali metal chlorides and bromides into organic solution. For a three-component mixture of solid LiCl, NaCl, and KCl, the ratio of salts extracted and complexed to the receptor in CDCl3 was 94:4:2, respectively. The same strong lithium selectivity was also observed in the case of a three-component mixture of solid LiBr, NaBr, and KBr where the ratio of extracted salts was 92:5:3. This observation is attributed to the unusually high solubility of lithium salts in organic solvents. The study suggests that ditopic receptors with an ability to extract solid salts as associated ion pairs may have application in separation processes.

Bromides↗
PubMed2004

Countercurrent supercritical fluid extraction and fractionation of high-added-value compounds from a hexane extract of olive leaves.

Countercurrent supercritical fluid extraction (CC-SFE) at a pilot scale plant was used for fractionation of high-added-value products from a raw extract of olive leaves in hexane. Compounds found in the raw extract were waxes, hydrocarbons, squalene, beta-carotene, triglycerides, alpha-tocopherol, beta-sitosterol, and alcohols. The CC-SFE extraction process was investigated according to a 2(3) full factorial experimental design using the following variables and ranges: extraction pressure, 75-200 bar; extraction temperature, 35-50 degrees C; and ethanol as modifier, 0-10%. Data were analyzed in terms of extraction yield, enrichment, recovery, and selectivity. Higher extraction yields were attained at 200 bar. For most of the compounds analyzed enrichment was attained at the same conditions, that is, 75 bar, 35 degrees C, and 10% ethanol. Hydrocarbons were usually recovered in the separators, whereas waxes and alpha-tocopherol remain in the raffinate. Selectivity data reveal that alpha-tocopherol is the most easily separable compound. The influence of the experimental factors on the recovery of all the compounds was studied by means of regression models. The best fitted model was attained for beta-sitosterol, with R2 = 99.25%.

Chemical Fractionation↗
PubMed2002

Non-covalent and semi-covalent molecularly imprinted polymers for selective on-line solid-phase extraction of 4-nitrophenol from water samples.

Two molecularly imprinted polymers (MIPs) have been synthesised for the selective extraction of 4-nitrophenol (4-NP) from water samples. One polymer was synthesised via a non-covalent approach and the other via a semi-covalent approach. The selectivity of the polymers for 4-NP was evaluated when these polymers were applied in on-line solid-phase extraction (MISPE) coupled to reversed-phase HPLC. The MISPE conditions for both MIPs were optimised and a clean-up step was included to eliminate non-specific interactions. Differences between the two MIPs were observed with the non-covalent MIP being the more selective of the two, whereas the recoveries were slightly higher for the semi-covalent MIP. The performance of the imprinted polymers in the MISPE of real water samples was also evaluated.

Chromatography, Liquid↗
PubMed1987

Selective solid-phase extraction of mexiletine from human serum prior to its GLC analysis.

A rapid and sensitive method for the GLC determination of mexiletine in human serum is described. The liquid-liquid extraction was replaced by the solid-phase extraction procedure for sample preparation using Separcol SI C 18 cartridges. The two-step elution of the cartridges after serum application was used-first with 50% acetonitrile in water for eluting endogenous compounds from serum, then with methanol to displace purified mexiletine. The recovery by this procedure was 83.6%. This selective solid-phase extraction offers an acceptable alternative to liquid extraction, and in combination with GLC-FID analysis is suitable for clinical pharmacokinetic studies of mexiletine.

Chromatography, Gas↗
PubMed2006

Application of liquid-phase microextraction and on-column derivatization combined with gas chromatography-mass spectrometry to the determination of carbamate pesticides.

A method has been established for the determination of five carbamate pesticides in water samples using liquid-phase microextraction (LPME) followed by on-column derivatization and gas chromatography-mass spectrometric (GC-MS) determination. Trimethylphenylammonium hydroxide (TMPAH) and trimethylsulfonium hydroxide (TMSH) were used as derivatization reagent for extracts prior to GC-MS analysis as carbamate pesticides are thermally labile compounds. Parameters that affect the extraction efficiency (selection of organic solvent and extraction time) and derivatization efficiency (choice of derivatization reagent and concentration of derivatization reagent) were investigated. The proposed method provided good enrichment factors up to 224, with reproducibility ranging from 4.86 to 7.81%, and good linearity from 1 to 400 microg/L. The limits of detection (LODs) ranged between 0.2 and 0.8 microg/L (S/N = 3) using GC-MS with selective ion monitoring. This method was applied to the determination of carbamate pesticides in tap water and waste water.

Carbamates↗
PubMed2006

Selective solid-phase extraction of tebuconazole in biological and environmental samples using molecularly imprinted polymers.

Molecularly imprinted polymers (MIPs) were prepared by precipitation polymerization using tebuconazole (TBZ) as a template. Frontal chromatography and selectivity experiments were used to determine the binding capabilities and binding specificities of different MIPs. The polymer that had the highest binding selectivity and capability was used as the solid-phase extraction (SPE) sorbent for the direct extraction of TBZ from different biological and environmental samples (cabbage, pannage, shrimp, orange juice and tap water). The extraction protocol was optimized and the optimum conditions were: conditioning with 5 mL methanol:acetic acid (9:1), 5 mL methanol and 5 mL water respectively, loading with 5 mL aqueous samples, washing with 1.2 mL acetonitrile (ACN):phosphate buffer (5:5, pH3), and eluting with 3 mL methanol. The MIPs were able to selectively recognize, effectively trap and preconcentrate TBZ over a concentration range of 0.5-15 micromol/L. The intraday and interday RSDs were less than 9.7% and 8.6%, respectively. The limit of quantification was 0.1 micromol/L. Under optimum conditions, the MISPE recoveries of spiked cabbage, pannage, shrimp, orange juice and tap water were 62.3%, 75.8%, 71.6%, 89% and 93.9%, respectively. MISPE gave better HPLC separation efficiencies and higher recoveries than C18 SPE and strong cation exchange (SCX) SPE.

Acetic Acid↗
PubMed2005

Assistive devices for balance and mobility: benefits, demands, and adverse consequences.

OBJECTIVES: To provide information on the advantages and possible disadvantages of using canes and walkers. DATA SOURCES: English-language articles were identified by searching MEDLINE and PubMed (1966-May 2003) for key words cane or walker , excluding articles unrelated to mobility aids. Bibliographies were reviewed and ISI Web of Science citation searches were run to identify additional references. Over 1000 articles were selected for further evaluation. STUDY SELECTION: We extracted all studies of single-tip canes or pickup walkers addressing: (1) functional, biomechanic, or neuromotor benefits; (2) biomechanic, attentional, neuromotor, metabolic, or physiologic demands; and (3) falls, injuries, or other problems. We included approximately 10% of the articles originally identified. DATA EXTRACTION: The methodology of each selected article, and findings relevant to the benefits, demands, or adverse effects of cane or walker use were summarized. DATA SYNTHESIS: Findings were synthesized by considering their relation to basic biomechanic principles. Some biomechanic findings appear to support the clinical view that canes and walkers can improve balance and mobility for older adults and people with other clinical conditions. However, a large proportion of users experience difficulties, and the use of such devices is associated with increased risk of falling. A small number of studies have characterized some of the specific demands and problems associated with using mobility aids. CONCLUSIONS: Clinical and biomechanic evaluations of canes and walkers confirm that these devices can improve balance and mobility. However, they can also interfere with ones ability to maintain balance in certain situations, and the strength and metabolic demands can be excessive. More research is needed to identify and solve specific problems. Such research may lead to improved designs and guidelines for safer use of canes and walkers.

Adolescent↗
PubMed2006

Development of a simple hollow fibre supported liquid membrane extraction method to extract and preconcentrate dinitrophenols in environmental samples at ng L(-1) level by liquid chromatography.

An easy and rapid hollow-fibre supported liquid membrane method (HFSLM) has been developed to extract and determinate the total concentration of four dinitrophenols in environmental water at ng L(-1) level. This extraction method provides a high selectivity, short extraction time and very low cost for real samples. It is a three-phase system, aqueous-organic-aqueous, where the organic solvent is held into the fibre pores, being in contact with the two other phases. The organic phase is formed by two different organic solvents, with two different polarities, n-undecane and toluene (1:1). The optimization step was performed using a three-variable Doehler design, involving three factors, stirring speed, fibre length and sample volume. The organic phase composition, as well as the pH of the acceptor and donor phases was also optimized. The extraction equilibrium was reached after 30 min, after which essentially the total amount (90-80%) of the four dinitrophenolic compounds were extracted from the sample. Better repeatability and reproducibility at the expense of lower enrichment factors was obtained compared with other methods, employing incomplete extraction during a fixed time. The matrix effect was tested by performing extractions from leachate water and river water. This method is linear in the range 0.1-100 microgL(-1) in different matrices, with detection limit around 100 ng L(-1), after extraction of 6 mL of sample and using high performance liquid chromatography for final analysis.

Analytic Sample Preparation Methods↗
PubMed2005

Application of single drop microextraction for analysis of chemical warfare agents and related compounds in water by gas chromatography/mass spectrometry.

Retrospective detection and identification of chemical warfare agents (CWAs) is important from the verification point of view of the Chemical Weapons Convention. In the present work, a novel method for determination of CWAs and their markers in water has been described. It is based on a single drop micro extraction (SDME) of analytes and gas chromatography/mass spectrometric identification. Extraction conditions, such as solvent selection, agitation, extraction time, and salt content, were found to have significant influence on SDME. The conditions optimized for extraction of CWAs were 1 microL CH2Cl2/CCl4 (3:1 v/v), 30-min extraction time, 300-rpm stirring rate, and with or without NaCl addition. Under optimized conditions, comparison of SDME, solid-phase microextraction, and liquid-liquid extraction was also made. The limit of detection by SDME ranged from 75 to 10 microg L(-1) at a signal-to-noise ratio of 10:1.

Analytic Sample Preparation Methods↗
PubMed2002

Structures and cytotoxic properties of sponge-derived bisannulated acridines.

A reinvestigation of sponge natural products from additional Indo-Pacific collections of Xestospongiacf. carbonaria and X. cf. exigua has provided further insights on the structures, biological activities, and biosynthetic origin of bisannulated acridines. These alkaloids include one known pyridoacridine, neoamphimedine (2), and three new analogues, 5-methoxyneoamphimedine (4), neoamphimedine Y (5), and neoamphimedine Z (6). A completely new acridine, alpkinidine (7), was also isolated. A disk diffusion soft agar assay, using a panel of five cancer cell lines (solid tumors and leukemias) and two normal cells, was used to evaluate the differential cytotoxicity (solid tumor selectivity) of the sponge semipure extracts and selected compounds including amphimedine (1), 2, 4, and 7. While all four compounds were solid tumor selective, 1 and 2 were the most potent and 4 was the most selective. The rationale used to characterize the new structures is outlined along with the related biosynthetic pathways envisioned to generate 2 and 7.

Acridines↗
PubMed2004

Toxic effects of lemon peel constituents on Ceratitis capitata.

A series of experiments were conducted to evaluate the toxicity of lemon peel extracts incorporated into mediterranean fruit fly Ceratitis capitata diet. Extracts were obtained with different solvents: diethyl ether, ethyl acetate, and methanol. All three extracts were toxic to some extent; the diethyl ether extract was selected for further studies. Ether extracts of lemon peel were prepared weekly over a 2-month period, from fruits collected on the 1st d of the bioassay. Weekly GC-MS and UV analyses of the extracts demonstrated that the concentration of citral and coumarins decreased in the peel after harvest. We conducted a series of bioassays to evaluate the toxicity of the ether extract, and mixtures of this extract with citral, 5,7-dimethoxycoumarin. and linalool incorporated to C. capitata larvae's natural diet (lemon slices endocarp) at a concentration of 250 microg/g of diet. Significant larvicidal activity can be obtained from a fresh lemon peel extract; however, when the extract was obtained from stored lemons, toxicity decreased. Addition of small amounts of citral or 5,7-dimethoxycoumarin, and linalool to the stored lemon peel extract would bring back the toxicity to the rates of fresh lemons extracts. Finally, female adults of C. capitata fed on diets containing additional amounts of ether extract, 5,7-dimethoxycoumarin, and linalool, were exposed to different photoperiods to test for phototoxicity. The treatment was toxic and affected the oviposition capacity of females depending on photoperiod.

Administration, Oral↗
PubMed2005

Acellular dermal matrix and hydroxyapatite in prevention of ridge deformities after tooth extraction.

The aim of this study was to evaluate the role of acellular dermal matrix graft (ADMG) acting as a membrane, associated with a resorbable hydroxyapatite (RHA) in bone regeneration to prevent ridge deformities after tooth extraction. Fifteen patients who had at least 2 noncontiguous, uniradicular teeth indicated for extraction were selected. In group I, the extraction sockets were covered by ADMG alone; and in group II, the alveoli were filled with RHA before the placement of the ADMG. After 6 months, re-entry surgeries and biopsies were performed. Although ridge thickness had been preserved in both groups, the means were significantly greater (P < 0.05) for group II when compared to group I (6,8 +/- 1.26 and 5.53 +/- 1.06). The histologic analysis showed small bone formation in some samples for group II, where the presence of a highly vascularized fibrous connective tissue surrounding the particles was a common finding. Based on the results, it can be concluded that the ADMG was able to preserve ridge thickness and that the additional use of RHA favored the preservation of the ridges along with an increase in the width of keratinized tissue.

Absorbable Implants↗
PubMed1998

A meta-analytic review of the effect of exercise on smoking cessation.

OBJECTIVE: To assess the effect of group exercise programs on smoking cessation. DATA SOURCES: A MEDLINE search, a manual review of journal articles, and a search of previous reviews were used. STUDY SELECTION: Published studies which 1) employed an exercise program for an intervention group and, 2) reported numbers of smokers of both exercise and control groups at baseline and at 6 to 24 months later were selected. DATA EXTRACTION: Five randomized trials were selected. In three of these, smoking cessation was the main aim and exercise was employed for relapse prevention concurrently with or after a group smoking cessation program. The studies produced a moderate qualitative score of 7 to 9 out of a 13 total score of modified DerSimonian's quality checklist. DATA SYNTHESIS: The summary odds ratio of the three studies which primarily aimed at smoking cessation was 2.35 (95% C.I. 0.75-7.31). When the two other studies were added, it dropped to 1.85 (95% C.I. 0.65-5.24). CONCLUSIONS: Due to the small number of studies and the small sample size for each study, the effect remains unclear. Further analysis, both qualitative and quantitative, is necessary to clarify these issues.

Adult↗