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At least 1,261 records · Page 70Linked to original sources
PubMed2001

Immunological characteristics of PEP carboxylase from leaves of C3-, C4- and C3-C4 intermediate species of Alternanthera--comparison with selected C3- and C4- plants.

Immunological cross-reactivity of phosphoenolpyruvate carboxylase (PEPC) in leaf extracts of C3-, C4- and C3-C4 intermediate species of Alternanthera (along with a few other C3- and C4- plants) was studied using anti-PEPC antibodies raised against PEPC of Amaranthus hypochondriacus (belonging to the same family as that of Alternanthera, namely Amaranthaceae). Antibodies were also raised in rabbits against the purified PEPC from Zea mays (C4- monocot-Poaceae) as well as Alternanthera pungens (C4- dicot-Amaranthaceae). Monospecificity of PEPC-antiserum was confirmed by immunoprecipitation. Amount of PEPC protein in leaf extracts of A. hypochondriacus could be quantified by single radial immunodiffusion. Cros- reactivity of PEPC in leaf extracts from selected C3-, C4-, and C3-C4 intermediate species (including those of Alternanthera) was examined using Ouchterlony double diffusion and Western blots. Anti-PEPC antiserum raised against A. hypochondriacus enzyme showed high cross-reactivity with PEPC in leaf extracts of A. hypochondriacus or Amaranthus viridis or Alternanthera pungens (all C4 dicots), but limited cross-reactivity with that of Zea mays, Sorghum or Pennisetum (all C4 monocots). Interestingly, PEPC in leaf extracts of Alternanthera tenella, A. ficoides, Parthenium hysterophorus (C3-C4 intermediates) exhibited stronger cross-reactivity (with anti-serum raised against PEPC from Amaranthus hypochondriacus) than that of Pisum sativum, Commelina benghalensis, Altenanthera sessilis (C3 plants). Further studies on cross-reactivities of PEPC in leaf extracts of these plants with anti-PEPC antisera raised against PEPC from leaves of Zea mays or Alternanthera pungens confirmed two points--(i) PEPC of C3-C4 intermediate is distinct from C3 species and intermediate between those of C3- and C4-species; and (ii) PEPC of C4-dicots was closer to that of C3-species or C3-C4 intermediates (dicots) than to that of C4-monocots.

Amaranthaceae↗
PubMed1999

Enzymatic measurement of sphingosine 1-phosphate.

Sphingosine 1-phosphate (SPP) is a sphingolipid metabolite which has novel dual actions acting as both an intracellular second messenger and a ligand for a family of G protein-coupled receptors. This paper describes a rapid enzymatic method to quantify mass levels of SPP in serum, mammalian tissues, and cultured cells. The assay utilizes an alkaline lipid extraction to selectively separate SPP from other phospholipids and sphingolipids, including sphingosine. Extracted SPP is efficiently converted to sphingosine by alkaline phosphatase treatment. Sphingosine thus formed is then quantitatively phosphorylated to [(32)P]SPP using recombinant sphingosine kinase and [gamma-(32)P]ATP. With this procedure we were able to obtain reproducible measurements of SPP over a broad range from 0.25 pmol to 2.5 nmol. In various rat tissues, levels of SPP varied between 0. 5 and 6 pmol/mg wet wt. The lowest levels were found in heart and testes, while brain contained the highest levels. The method was adapted easily to measure minute amounts of SPP present in various cultured cell types. The amount of SPP in cell extracts was proportional to the cell number and varied between 0.04 and 2 pmol/10(6) cells. Concurrent measurements of sphingosine levels revealed that its concentration was significantly higher than SPP in most cells and tissues. Furthermore, with this assay we were able to measure increases in intracellular SPP levels in rat pheochromocytoma PC12 cells after treatment with exogenous sphingosine or with nerve growth factor which stimulates sphingosine kinase activity.

Adenosine Triphosphate↗
PubMed2000

Miniaturised pressurised liquid extraction of polycyclic aromatic hydrocarbons from soil and sediment with subsequent large-volume injection-gas chromatography.

Analyte extraction is the main limitation when developing at-line, or on-line, procedures for the preparation of (semi)solid environmental samples. Pressurised liquid extraction (PLE) is an analyte- and matrix-independent technique which provides cleaner extracts than the time-consuming classical procedures. In the study, the practicality of miniaturised PLE performed in a stainless-steel cell, and combined with subsequent large-volume injection (LVI)-GC-MS was studied. As an example, the new system was applied to the determination of polycyclic aromatic hydrocarbons (PAHs) in soils and a sediment. Variables affecting the PLE efficiency, such as pressure and temperature of the extraction solvent and total solvent volume, were studied. Toluene was selected as extraction solvent and a total solvent volume of 100 microl was used for the 10 min static-dynamic PLE of 50-mg samples. Additional clean-up or filtration of the sample extracts was not required. Detection limits using LVI-GC-MS were below 9 ng/g soil for the 13 PAHs more volatile than indeno[1,2,3-cd]pyrene in real soil samples and the repeatability of the complete PLE plus LVI-GC-MS method for the analysis of the endogenous PAH was better than 15%. Comparison of PLE and Soxhlet or liquid-partitioning extraction results for the analysis of non-spiked samples showed that the efficiency of PLE is the same or better than for the other two extraction methods assayed.

Gas Chromatography-Mass Spectrometry↗
PubMedDate not supplied

Determination of polychlorinated biphenyls in sediments, using sonication extraction and capillary column gas chromatography-electron capture detection with internal standard calibration.

A sonication technique is presented for the extraction of polychlorinated biphenyls (PCBs) from sediments. In addition, a quantitation scheme is described which allows peak-specific and, in many cases, congener-specific determination of PCBs. PCBs are quantitated by capillary column gas chromatography-electron capture detection, with internal standard calibration. Results utilizing sonication extraction were compared with those obtained by Soxhlet and steam distillation extractions of 3 U.S. Environmental Protection Agency (EPA) quality control sediment samples and 3 lake sediments known to be contaminated with PCBs. Environmental lake sediments were extracted wet, with no drying prior to extraction. Recoveries by each technique varied depending on the sediment sample being extracted and degree of chlorination of PCB congeners. With proper selection of extraction solvent, the sonication technique can recover amounts of PCBs equivalent to and sometimes greater than recoveries by the Soxhlet or steam distillation techniques. A 24-h quiescent period in the extraction solvent between 2 sonications improved extraction efficiency for 2 freeze-dried sediments but did not affect results obtained for 3 environmentally contaminated sediments that were extracted without drying. Replacement of Soxhlet extraction with the sonication technique results in reduced sample preparation time, decreased volumes of solvents and sample, and substitution of common laboratory glassware in place of fragile, expensive Soxhlet glassware. Sonication extraction can also improve precision compared with Soxhlet extraction.

Chromatography, Gas↗
PubMed2006

Selective recovery of tagatose from mixtures with galactose by direct extraction with supercritical CO2 and different cosolvents.

A selective fractionation method of carbohydrate mixtures of galactose/tagatose, using supercritical CO(2) and isopropanol as cosolvent, has been evaluated. Optimization was carried out using a central composite face design and considering as factors the extraction pressure (from 100 to 300 bar), the extraction temperature (from 60 to 100 degrees C), and the modifier flow rate (from 0.2 to 0.4 mL/min, which corresponded to a total cosolvent percentage ranging from 4 to 18% vol). The responses evaluated were the amount (milligrams) of tagatose and galactose extracted and their recoveries (percent). The statistical analysis of the results provided mathematical models for each response variable. The corresponding parameters were estimated by multiple linear regression, and high determination coefficients (>0.96) were obtained. The optimum conditions of the extraction process to get the maximum recovery of tagatose (37%) were 300 bar, 60 degrees C, and 0.4 mL/min of cosolvent. The predicted value was 24.37 mg of tagatose, whereas the experimental value was 26.34 mg, which is a 7% error from the predicted value. Cosolvent polarity effects on tagatose extraction from mixtures of galactose/tagatose were also studied using different alcohols and their mixtures with water. Although a remarkable increase of the amount of total carbohydrate extracted with polarity was found, selective extraction of tagatose decreased with increase of polarity of assayed cosolvents. To improve the recovery of extracted tagatose, additional experiments outside the experimental domain were carried out (300 bar, 80 degrees C, and 0.6 mL/min of isopropanol); recoveries >75% of tagatose with purity >90% were obtained.

Carbon Dioxide↗
PubMed2006

Economic evaluations of single- versus double-embryo transfer in IVF.

Multiple pregnancies lead to complications and induce high costs. The most successful way to decrease multiple pregnancies in IVF is to transfer only one embryo, which might reduce the efficacy of treatment. The objective of this review is to determine which embryo-transfer policy is most cost-effective: elective single-embryo transfer (eSET) or double-embryo transfer (DET). Several databases were searched for (cost* or econ*) and (single embryo* or double embryo* or one embryo* or two embryo* or elect* embryo or multip* embryo*). On the basis of five exclusion criteria, titles and abstracts were screened by two individual reviewers. The remaining papers were read for further selection, and data were extracted from the selected studies. A total of 496 titles were identified through the searches and resulted in the selection of one observational study and three randomized studies. Study characteristics, total costs and probability of live births were extracted. Besides this, cost-effectiveness and incremental cost-effectiveness were derived. It can be concluded that DET is the most expensive strategy. DET is also most effective if performed in one fresh cycle. eSET is only preferred from a cost-effectiveness point of view when performed in good prognosis patients and when frozen/thawed cycles are included. If frozen/thawed cycles are excluded, the choice between eSET and DET depends on how much society is willing to pay for one extra successful pregnancy.

Embryo Transfer↗
PubMed1995

Nonsurgical treatment of open bite in nongrowing patients.

Successful treatment of the adult patient with an open bite dental or skeletal pattern often presents a difficult challenge. While the causes of open bite may be multifactorial in nature, there are specific diagnostic criteria that may allow for an orthodontic treatment modality incorporating extraction therapy with retraction of incisors. Two case presentations illustrate treatment of adult patients with open bites due to proclined incisors. The diagnostic criteria and mechanics for appropriate and successful treatment are discussed. Although the selection of extraction therapy for correction of anterior open bite has a narrow range of application in the overall scheme of open bite treatment, this treatment method has certain areas of application in which success may be anticipated.

Adult↗
PubMed2002

Smart nanotubes for bioseparations and biocatalysis.

Tube-shaped nanostructures (nanotubes) have a number of attributes that make them potentially useful for biomedical applications such as drug delivery/detoxification and enzyme immobilization. Template synthesis provides a route for preparing monodisperse nanotubes of nearly any size and composed of nearly any material. We show here that template-synthesized silica nanotubes can be biochemically functionalized such that they act as biocatalysts and highly selective nano-phase extraction agents for bioseparations. For example, nanotubes containing an enantioselective antibody selectively extract the enantiomer of a drug molecule that binds to the antibody, relative to the enantiomer that has no specific interaction with the antibody. Nanotubes containing the enzyme glucose oxidase function as nanophase bioreactors to catalyze the oxidation of glucose.

Antibodies↗
PubMed2005

Effect of solvent, temperature, and solvent-to-solid ratio on the total phenolic content and antiradical activity of extracts from different components of grape pomace.

Grape byproducts were subjected to an extraction process under various different experimental conditions (namely, solvent type, temperature, solvent-to-solid ratio, time contact, and raw material) in order to study the effect of these conditions on the yield of phenolic compounds and the corresponding antiradical activity of extracts. Although the order of decreasing capacity to extract soluble materials was ethanol > methanol > water, methanol was the most selective for extracting phenolic compounds. Temperature and solvent-to-solid ratio were found to have a critical role in extraction efficiency; values of 50 degrees C (between 25 and 50 degrees C) and 1:1 (between 1:1 and 5:1) maximized the antiradical activity of phenolic extracts. In addition, extracts from grape samples previously subjected to distillation reached higher antiradical values in comparison to those coming directly from pressing; in both cases, seed extracts showed better results than those of stem when ethanol or water was employed, whereas the opposite occurred in the case of methanol. These differences were attributed to the different phenolic compositions of the considered fractions.

Free Radicals↗
PubMed1992

Isolation of Nocardia asteroides from respiratory specimens by using selective buffered charcoal-yeast extract agar.

Nocardiosis is difficult to diagnose clinically and by laboratory methods. A patient presented with disease compatible with pulmonary malignancy, but Nocardia asteroides was isolated on buffered charcoal-yeast extract agar. Investigation revealed that this medium may be a suitable selective primary isolation medium for Nocardia species from respiratory specimens.

Animals↗
PubMed2002

Selective cytotoxicity evaluation in anticancer drug screening of fractionated plant extracts.

Chosen to reflect biodiversity in a phylogenetic sense, 100 fractionated plant extracts were screened in vitro for cytotoxicity following extraction and fractionation (polypeptide isolation). Of these 100 extracts, 30 were selected and then characterized preliminarily for antitumor potency and mode of action by testing them on two cell lines and primary cultures of human tumor cells. On the basis of cytotoxicity potency, 10 of the extracts were further characterized for anticancer activity in 10 human tumor cell lines. This final testing resulted in seven potential lead plants with superior evidence of antitumor potential: Colchicum autumnale L. (Colchicaceae), Digitalis lanata Ehrh. and Digitalis purpurea L. (Plantaginaceae), Helleborus cyclophyllus Boiss. (Ranunculaceae), Menyanthes trifoliata L. (Menyanthaceae), and Viola arvensis Murr. and Viola patrinii Ging. (Violaceae). Within a database of antitumor compounds, the activity profiles of the extracts from these seven plants were compared, by correlation analysis, with those of more than 100 other compounds, including 39 standard drugs from different classes of cytotoxic mechanisms. The activity profiles of six of these candidates were uncorrelated with those of the standard drugs, possibly indicating new pathways of drug-mediated cell death.

Antineoplastic Agents, Phytogenic↗
PubMed1975

[Orthodontic therapy by tooth extraction--indication and prognosis].

From 1000 current orthodontic treatments, a percentage of 23.3 (233 patients) was selected for extraction therapy. The indication and the prognosis were analysed from various viewpoints to deduce suggestions for the application in practice. The advantages described and the possibilities of use meet the demands on efficient orthodontic therapy.

Adult↗
PubMedDate not supplied

[Extraction, separation and quantitative determination of prostaglandins in blood, thrombocytes and several tissues].

Modified methods, using selective organic extraction and absorption-distributional column chromatography, are described for isolation of prostglandines with high yield; the substances were differentiated by means of the methods used into series A, E, F. Use of radioimmunologic method enabled to obtain data on content of prostglandines in blood plasma and in thrombocytes of healthy people and of patients with ischemic heart impairments as well as on content of these substances in rabbit blood plasma, fatty and livery tissues.

Adipose Tissue↗
PubMed2005

Feature extraction from Doppler ultrasound signals for automated diagnostic systems.

This paper presented the assessment of feature extraction methods used in automated diagnosis of arterial diseases. Since classification is more accurate when the pattern is simplified through representation by important features, feature extraction and selection play an important role in classifying systems such as neural networks. Different feature extraction methods were used to obtain feature vectors from ophthalmic and internal carotid arterial Doppler signals. In addition to this, the problem of selecting relevant features among the features available for the purpose of classification of Doppler signals was dealt with. Multilayer perceptron neural networks (MLPNNs) with different inputs (feature vectors) were used for diagnosis of ophthalmic and internal carotid arterial diseases. The assessment of feature extraction methods was performed by taking into consideration of performances of the MLPNNs. The performances of the MLPNNs were evaluated by the convergence rates (number of training epochs) and the total classification accuracies. Finally, some conclusions were drawn concerning the efficiency of discrete wavelet transform as a feature extraction method used for the diagnosis of ophthalmic and internal carotid arterial diseases.

Automation↗
PubMedDate not supplied

Comparison of mineral trioxide aggregate and formocresol as pulp-capping agents in pulpotomized primary teeth.

PURPOSE: The aim of this study was to use clinical, radiographic, and histologic examinations to compare the relative success of gray mineral trioxide aggregate (MTA), white MTA, and formocresol as pulp dressings in pulpotomized primary teeth. METHODS: Twenty-four children, each with at least 3 primary molars requiring pulpotomy, were selected for this study's clinical and radiographic portion. An additional 15 carious primary teeth planned for serial extraction were selected for this study's histologic portion. All selected teeth were evenly divided into 3 test groups and treated with pulpotomies. Gray MTA was used as the pulp dressing for one third of the teeth, white MTA was the dressing for one third, and the remaining one third were treated with formocresol. The treated teeth selected for the clinical and radiographic evaluations were monitored periodically for 12 months. The treated teeth selected for histologic study were monitored periodically and extracted 6 months postoperatively. RESULTS: Four children with 12 pulpotomized teeth failed to return for any follow-up evaluations in the clinical and radiographic study. Of the remaining 60 teeth in 20 patients, 1 tooth (gray MTA) exfoliated normally and 6 teeth (4 white MTA and 2 formocresol) failed due to abscesses. The remaining 53 teeth appeared to be clinically and radiographically successful 12 months postoperatively. Pulp canal obliteration was a radiographic finding in 11 teeth treated with gray MTA and 1 tooth treated with white MTA. In the histologic study, both types of MTA successfully induced thick dentin bridge formation at the amputation sites, while formocresol induced thin, poorly calcified dentin. Teeth treated with gray MTA demonstrated pulp architecture nearest to normal pulp by preserving the odontoblastic layer and delicate fibrocellular matrix, yet few inflammatory cells or isolated calcified bodies were seen. Teeth treated with white MTA showed a denser fibrotic pattern, with more isolated calcifications in the pulp tissue along with secondary dentin formation. CONCLUSIONS: Gray MTA appears to be superior to white MTA and formocresol as a pulp dressing for pulpotomized primary teeth.

Aluminum Compounds↗
PubMed1998

Recovery of the immune system with antiretroviral therapy: the end of opportunism?

OBJECTIVE: Clinical care of people infected with human immunodeficiency virus (HIV) has been substantially affected by the introduction of potent antiretroviral therapy. Changes in the immune system after such therapy and the clinical consequences are important issues for clinicians treating patients with HIV. DATA SOURCES: A systematic review of MEDLINE, 1993 to January 1998, of peer-reviewed publications, abstracts from national and international conferences, and product registration information through January 1998. STUDY SELECTION AND DATA EXTRACTION: Criteria used to select studies include relevance to immune reconstitution with potent antiretroviral therapy and having been published in the English language. Assessment of data quality and validity included consideration of venue of the publication and relevance to practice. DATA SYNTHESIS: Suppression of viral replication after administration of potent antiretroviral therapy that includes inhibitors of the HIV-1 protease is associated with quantitative and qualitative changes in the immune system. In patients with relatively advanced disease, there is a first-phase rise (during the initial 3 months) in both naive and memory CD4+ and CD8+ T lymphocytes and B lymphocytes. This is followed by a slower second-phase increase (after 3 months) in cells primarily of the naive CD4+ and CD8+ phenotypes. These quantitative changes are associated with qualitative improvements in host immune responses, best characterized by dramatically reduced risk of opportunistic infection. Restoration of the immune system during the first year of potent antiretroviral therapy is partial at best. CONCLUSIONS: Potent antiretroviral therapy has become the standard of care for people with HIV infection, and its use has led to significant reductions in the incidence of the acquired immunodeficiency syndrome (AIDS) and in mortality from HIV infection. Although incomplete, considerable immune recovery occurs, sufficient, in most cases, to provide adequate protection against most AIDS-associated opportunistic infections.

AIDS-Related Opportunistic Infections↗
PubMed2006

Integrated approach using protein and ligand information to analyze selectivity- and affinity-determining features of carbonic anhydrase isozymes.

The application and comparison of selected protein- and ligand-based approaches to elucidate factors important for affinity and selectivity towards the carbonic anhydrase isozymes I, II, and IV are described. Carbonic anhydrases are abundant in pro- and eukaryotes. These enzymes catalyze the reversible hydration of carbon dioxide to bicarbonate and H(+) ions and are thus involved in many important physiological and pathophysiological processes. Due to the fact that the human carbonic anhydrase family consists of 16 closely related isozymes, the design of selective inhibitors is a special challenge for medicinal chemists. In order to extract selectivity-determining features, we applied purely ligand-based 3D QSAR techniques as well as qualitative comparative molecular field analyses of the targets' binding sites using consensus principal component analysis (CPCA). The dataset for the QSAR studies was deliberately compiled from 1,748 inhibitors and comprises about 140 ligands, mainly of the sulfonamide type. Additionally, we employed the novel AFMoC approach, which intrinsically combines protein and ligand information. The simultaneous use of these different techniques gives deeper insight into selectivity and affinity-determining features and provides quantitative models for prediction.

Carbonic Anhydrase Inhibitors↗
PubMed2001

Effect of moisture on the extraction efficiency of polycyclic aromatic hydrocarbons from soils under atmospheric pressure by focused microwave-assisted extraction.

The effects of the moisture content in the original, air-dried and re-moistened matrices as well as solvent have been studied on the recovery of polycyclic aromatic hydrocarbons (PAHs) from soil by a focused microwave-assisted extraction (FMAE) method. Solvents selected for the extractions were cyclohexane-acetone (1:1), hexane-acetone (1:1) and dichloromethane. On the extraction of 20-day aged spiked soil, the highest recovery was found by applying hexane-acetone mixture. Spiked soil sample, quality control sample and real soil sample were used for the evaluation of moisture effect. It indicated that the presence of water in the soil is important for the recovery enhancement of PAHs and with this presence it is possible to avoid drying step with the FMAE technique. A comparison between microwave and 16-h Soxhlet methods has been made. It evidenced that the microwave-assisted extraction under ambient atmospheric pressure is a suitable alternative to Soxhlet extraction for the analysis of PAHs in soils.

Atmospheric Pressure↗