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At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

[Chromatographic fractionation of scraping components of frog olfactory tissues. Preparation of fractions capable of sensitizing artificial lipid membrane to odorants].

The fractionation of frog olfactory preparation by ion-exchange chromatography and gel filtration permitted to obtain fractions capable of making artificial lipid membranes sensitive to odorants, such as camphora, musc ambrette and linalool. The sensitizing agent present in active fractions is a high-molecular-weight (m.w. 100,000) protein containing substance. It is suggested that this agent is a component of a special transport system which may carry the odorous molecules to olfactory receptor cells or to remove them from olfactory tissues.

Animals↗
PubMed1976

Simple determination of 3alpha-hydroxy fraction and 3beta-hydroxy fraction of urinary 17-ketosteroids.

We describe a method for determination of the 3alpha-hydroxysteroid fraction and 3beta-hydroxysteroid fraction of 17-ketosteroids in urine. The method includes enzymatic hydrolysis with beta-glucuronidase and extraction with ethyl acetate and color development of 3beta-hydroxysteroids by 3beta-hydroxysteroid oxidase and of total 17-ketosteroids by the Zimmermann reaction. The value for 3alpha-hydroxysteroids is calculated by subtracting the value for 3beta-hydroxysteroids from the value for total 17-ketosteroids. Recovery was assessed and results compared with those by an accepted method. Results were satisfactory for measuring these fractions of 17-ketosteroids.

17-Ketosteroids↗
PubMed1992

Mitogenic activity of high molecular polysaccharide fractions isolated from the cuppressaceae Thuja occidentalis L. enhanced cytokine-production by thyapolysaccharide, g-fraction (TPSg).

Thuja polysaccharide g fraction (TPSg) was shown to be an inducer of the CD4+ fraction of the human peripheral blood T-cell subset (1,2). Furthermore, it could be demonstrated that TPSg is a potent inhibitor of the expression of HIV-1-specific antigens and of the HIV-1-specific reverse transcriptase (3). This report deals with the cytokine pattern induced by TPSg in human peripheral blood lymphocyte (PBL) and purified monocyte/macrophage cultures. In addition, a further characterization of the CD4+ T-cell fraction stimulated by TPSg was performed by FACS analysis. TPSg is induces IL-1 beta, IL-2, IL-3, IL-6, gamma-IFN, G-CSF, GM-CSF, and TNF-beta production in PBL cultures; and IL-1 beta and IL-6 in monocyte/macrophage cultures. Enzyme-linked immunosorbent assays (ELISAs) demonstrated that no IL-4 was produced by PBL cultures under TPSg influence.

Cytokines↗
PubMed1983

[Inhibition of an immune hemolysis reaction in higher vertebrates by a serum fraction (fraction P) from the pregnant Salamandra salamandra L].

Serum "fraction P" from Salamandra pregnant female (containing essentially an alpha 2-macroglobulin) possesses non specific cellular immunosuppressive properties [2]. This fraction has been tested in an immune hemolysis reaction: hemolytic Rabbit IgG + guinea-pig complement + Sheep erythrocytes. This fraction, after incubation with guinea-pig complement, inhibits immune lysis.

Animals↗
PubMedDate not supplied

[Fractionation of serum by gel filtration: contamination of IgM fractions by non-specific inhibitors of hemagglutination of the rubella virus].

Rubella virus hemagglutination non-specific inhibitors, in sera fractionated on Bio-Gel A 5 m, elute in IgM containing fractions. In addition, in heparin-MnCl2 treated sera, the same inhibitors display a different chromatographic behaviour on Bio-Gel A 5m, being eluted earlier than IgM. Therefore, in order to avoid false-positive results due to the presence of non-specific inhibitors in IgM containing fractions it is necessary to verify the disappearance of hemagglutination-inhibition activity after 2-ME reduction.

Blood Chemical Analysis↗
PubMed1975

[A new vaccinating antigenic fraction obtained from "Vibrio cholerae" II. Biological properties of the Ch1+2 fraction compared with the bacterial vaccine (author's transl)].

This fraction inoculated into mice protects against experimental infection. This fraction induces in various experimental animals serological modifications which are characterized by a rise in the vibriocidal effect of the serum. Controlled experiments in animals and humans showed that the vibriocidal effect is greater than the one obtained by the bacterial vaccine and persist far more longer. The vibriocidal power of the serum can also be obtained at titers relatively high when the fraction is given by the oral route. The in situ vaccination reduces the duration and the numbers of the excreted bacteries in germ free and pathogen free mice.

Animals↗
PubMed1976

Separation of populations of sensitized lymphoid cells into fractions inhibiting and fractions enhancing syngeneic tumor growth in vivo.

Separation of subpopulations of lymphoid cells sensitized against a syngeneic tumor was attempted by means of velocity sedimentation and the fractions were injected together with tumor cells into syngeneic hosts. Spleen cells from tumor-bearing mice or spleen cells sensitized on tumor cell monolayers could be fractionated into a subpopulation capable of inhibiting growth of the same tumor and a separable fraction which enhanced tumor growth. Activity of the tumor-inhibiting lymphocytes was not apparent in the presence of the tumor-enhancing cells. The former activity was associated with small lymphocytes and the latter with injection of larger cells. Preliminary experiments investigated the developmental relation between the cells responsible for these opposing activities.

Animals↗
PubMed2005

Comprehensive proteomics in yeast using chromatographic fractionation, gas phase fractionation, protein gel electrophoresis, and isoelectric focusing.

We have investigated the use of a variety of different techniques to identify as many proteins as possible in a yeast lysate, with the aim of investigating the overlap and complementarity of data from different approaches. A standard lysate was prepared from log phase yeast (Saccharomyces cerevisiae). This was then subjected to analysis via five different approaches aimed at identifying as many proteins as possible using an ion trap mass spectrometer. The total number of non-redundant protein identifications from each experiment was: 524 proteins by 2-D (SCX/C18) nanoflow liquid chromatography-liquid chromatography tandem mass spectrometry (nanoLC-LC MS/MS (MudPIT)); 381 proteins by nanoLC-MS/MS with gas phase fractionation by mass range selection; 390 proteins by nanoLC-MS/MS with gas phase fractionation by ion abundance selection; 898 proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) separation of proteins, in-gel digestion, and nanoLC-MS/MS of gel slices; and 422 proteins by isoelectric focusing of proteins, in-gel digestion and nanoLC-MS/MS of gel slices. The total number of non-redundant protein identifications in the five experiments was 1204. Combining only the two best experiments, the SDS-PAGE gel slices and the Mudpit, produces 1024 proteins identified, more than 85% of the total. Clearly, combining a Mudpit analysis with an SDS-PAGE gel slice experiment gives the greatest amount of protein identification information from a limited amount of sample.

Chemical Fractionation↗
PubMed1985

Simultaneous preparation of membrane fractions from small amounts of skeletal muscle: a study on mitochondrial and microsomal fractions from MedJ mice.

This work is the first biochemical study of skeletal muscle membranes isolated from mice displaying an inherited neuromuscular disease: MedJ strains. It is focused on the research of a possible alteration of membrane biological activities related to this disease. We describe a procedure which allows the simultaneous preparation of mitochondrial and microsomal fractions from a small amount of skeletal muscle. When EGTA and BSA are present in the buffers, functional mitochondria can be prepared. Under these conditions we found that no major modification occurs for this disease at the mitochondrial inner membrane level. A dramatic impairment of a calcium active transport activity found in the microsomal fraction obtained from MedJ is noticed, suggesting that some modification may occur at this level.

Animals↗
PubMed1990

Comparative study of the N-glycoprotein synthesis through dolichol intermediates in mitochondria, Golgi apparatus-rich fraction and endoplasmic reticulum-rich fraction.

1. Glycosylation of endogenous dolichol acceptors was higher in mitochondria than in C 30,000 g (Golgi apparatus-rich fraction) and C 100,000 g (endoplasmic reticulum-rich fraction). 2. In mitochondria, N-glycoprotein biosynthesized were composed of high mannose type and non-fucosylated biantennary complex type while in C 30,000 g and C 100,000 g preparations, they contained biantennary complex type as tri and tetraantennary complex type oligosaccharides in both fucosylated and non-fucosylated forms.

Animals↗
PubMed1984

Diurnal changes in the fraction of 3-hydroxy-3-methylglutaryl-CoA reductase in the active form in rat liver microsomal fractions.

'Initial' and 'total' activities of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase) were measured in cold-clamped samples of liver from rats at 2h intervals throughout the 24h light/dark cycle. Initial activities were obtained in microsomes (microsomal fractions) isolated and assayed in the presence of 100mM-KF, whereas 'total' activities were measured in microsomes prepared from the same homogenates but washed free of KF and incubated with exogenous partially purified rat liver protein phosphatase. The initial/total-activity ratio for HMG-CoA reductase underwent a diurnal cycle, which had a nadir 4h into the light phase (when initial activity was 28% of total activity) and a peak 12h later, i.e. 4h into the dark phase (when initial activity was 80% of total activity). These low and high points of the cycle were separated by gradual steady changes in the ratio. The characteristics of this diurnal cycle were different from those of the cycle observed for total activity, which had a plateau of high activity between 2 and 10h into the dark cycle preceded and succeeded by a very rapid increase and decrease, respectively, in the total activity of HMG-CoA reductase. The combination of the two cycles resulted in the dampening of the resultant cycle for the initial or effective activity of HMG-CoA reductase, such that the changes in initial activity around the beginning and and end of the dark phase were more gradual than would otherwise have been the case if the initial/total-activity ratio for HMG-CoA reductase were constant throughout the diurnal cycle. The physiological implications of the observed diurnal variation in the fraction of hepatic HMG-CoA reductase in the active form are discussed.

Animals↗
PubMed1989

Inactivation and elimination of viruses during the fractionation of an intravenous immunoglobulin preparation: liquid heat treatment and polyethylene glycol fractionation.

A method for the heat treatment of human IgG solution at 60 degrees C for 10 h was established. Human immunodeficiency, mumps, vaccinia and 4 other viruses were added to the IgG solution in 33% sorbitol and heated at 60 degrees C. Those viruses were inactivated within 1 h. Heat-treated intravenous IgG (IVIG-H) was prepared by heat treatment and polyethylene glycol (PEG) fractionation. Conventional nonheated intravenous IgG (IVIG-C) was prepared from the same source paste by the fractionation method. No physicochemical or biological difference was observed between the heated and control IVIG preparations.

Animals↗
PubMedDate not supplied

Biochemical and morphological studies of rat submandibular gland: I. Centrifugal fractionation of granule-rich fraction.

Submandibular glands from male rats were homogenized in 0.34 M sucrose and 0.5 mM ethylenediaminetetraacetic acid in 10 mM HEPES buffer at a pH of 7.4. The extract was centrifuged and filtered through nuclepore filters to prepare a granule-rich fraction. Electron dense zymogen granules constituted approximately 85% of the particles in this fraction which also contained about a third of the total alkaline esterase activity in the gland.

Acid Phosphatase↗
PubMed1996

Model-based estimation of the excess fraction (attributable fraction): day care and middle ear infection.

The methods of adjustment for estimation of the excess fraction (EF), or attributable fraction, based on conventional and dynamic (or regressive or autoregressive) logistic regression modelling in a cohort study for a disease with recurrent episodes are considered. Throughout the paper, the computation of estimates with corresponding confidence intervals is illustrated in a cohort study associating the incidence of acute middle ear infection (acute otitis media) with type of day care in northern Finland. The incidences of at least one episode and at least three episodes as well as the total number of episodes during the first two years of life are considered. In our example, the estimates obtained from the dynamic model appear to have smaller standard errors since the dynamic model effectively utilizes the time-dependency of the covariates.

Child Day Care Centers↗
PubMed2006

Site of fresh gas inlet and ratios of the delivered fraction and inspired fraction of inhaled isoflurane and sevoflurane in low-flow anesthesia.

PURPOSE: The use of low-flow anesthesia causes a discrepancy between the delivered fraction (FD) and the inspired fraction (FI) of inhaled gases. We compared the FI/FD ratios of a new circle (fresh gas inlet located between the inspiratory valve and the patient) to those of the conventional circle (fresh gas inlet located between the inspiratory valve and the CO2 absorber) in low-flow isoflurane and sevoflurane anesthesia, using three anesthetic machines (Dräger NM-GS, Dräger Fabius-GS, and ACOMA KMA-1300-III). METHODS: Eighty-two patients were randomly assigned to three experimental groups. For experiment 1, 32 patients were allocated to the NM-GS conventional/new, NM-GS new/conventional, ACOMA conventional/new, and ACOMA new/conventional groups. For experiment 2, 14 patients were allocated to ACOMA conventional/conventional and ACOMA new/new groups to measure isoflurane FI/FD ratios. For experiment 3, 36 patients were allocated to ACOMA conventional/conventional, ACOMA new/new, Fabius conventional/conventional, and Fabius new/new to measure sevoflurane FI/FD ratios. RESULTS: In experiment 1, the NM-GS showed no significant changes in the FI/FD ratios. However, in the ACOMA, the new circle improved the FI/FD ratio. In experiment 2, the isoflurane FI/FD ratios in the new circle of the ACOMA were significantly higher than those in the conventional circle. In experiment 3, the sevoflurane FI/FD ratios in the new circle of both the ACOMA and the Fabius were significantly higher than those in the conventional circles. CONCLUSION: The positioning of the fresh gas inlet between the inspiratory valve and the patient improved the FI/FD ratios of both isoflurane and sevoflurane during low-flow anesthesia in two decoupling-style anesthetic machines (ACOMA and Fabius).

Adult↗
PubMed1994

Increased susceptibility to oxidation of vitamin E in mitochondrial fractions compared with synaptosomal fractions from rat brains.

The in vitro oxidation of vitamin E (alpha tocopherol) in rat brain synaptosomes and mitochondria by 2,2'-azo-bis-(2'-amidinopropane) dihydrochloride (ABAPH), a free radical generator, was studied. Subcellular fractions (300 micrograms total protein) were suspended in different buffers at pH 7.4 and incubated at 37 degrees C. In the presence of 0.5 mM ABAPH the mitochondrial alpha tocopherol began to get oxidized after a lag time or induction time of 15 min compared with a lag time of 30 min for the synaptosomal fraction. Thus the reserve of reducing compounds that are responsible for delaying tocopherol oxidation is less in mitochondria than in synaptosomes. More tocopherolquinone was produced during incubations without ABAPH compared with incubations in the presence of ABAPH suggesting that the mechanism of oxidation of tocopherol differs under these two conditions. When mitochondria were incubated in buffer without oxidants the production of tocopherolquinone preceded that of thiobarbituric acid reactive substances, an indicator of peroxidation of fatty acids. Therefore, alpha tocopherol is active as an anti-oxidant in mitochondrial membranes and the production of alpha tocopherolquinone could be a monitor of mild membrane oxidation under in vitro conditions. The ease of oxidation of mitochondrial tocopherol suggests a general vulnerability of the mitochondrial membranes to oxidation. Adding vitamin E or its water soluble analogs during in vitro experiments may improve the stability and viability of mitochondria. Furthermore, antioxidant protection by vitamin E may be crucial for the maintenance of tissues, such as brain, whose function is critically dependent upon the availability of high energy phosphates.(ABSTRACT TRUNCATED AT 250 WORDS)

Amidines↗
PubMed1992

Acetylcholine synthesis is modulated by acetylcholine content of cytosolic fraction but not by that of releasable fraction.

Synthesis and release of acetylcholine (ACh) in the rat hippocampal slices were examined to clarify the mechanism of modulation of ACh synthesis. Treatment with 2-(4-phenylpiperidino)cyclohexanol (AH5183, 50 microM), an inhibitor of ACh transport from cytosol to synaptic vesicles, inhibited the increase in ACh content of the membrane-bound fraction which is readily releasable, but did not affect the cytosolic ACh content. Under these conditions, the total ACh content reached a plateau value. These results indicate that ACh synthesis is modulated by cytosolic ACh content but not by the vesicular fraction.

Acetylcholine↗
PubMed1985

Videodensitometric ejection fraction from intravenous digital subtraction right ventriculograms: correlation with first pass radionuclide ejection fraction.

Thirty-one consecutive patients undergoing intravenous blurred mask digital subtraction right ventriculography were submitted to first pass radionuclide angiography. Second order mask resubtraction of end-diastolic and end-systolic right ventricular digital image frames was executed using preinjection end-diastolic and end-systolic frames to rid the digital subtraction images of mis-registration artifact. End-diastolic and end-systolic perimeters were drawn manually by two independent observers with a light pen. Ejection fractions calculated from the integrated videodensitometric counts within these perimeters correlated well with those derived from the first pass radionuclide right ventriculogram (r = 0.84) and the interobserver correlation was acceptable (r = 0.91). Interobserver differences occurred more frequently in patients with atrial fibrillation and in those whose tricuspid valve planes were difficult to discern on the digital subtraction right ventriculograms. These results suggest that videodensitometric analysis of digital subtraction right ventriculograms is an accurate method of determining right ventricular ejection fraction and may find wide clinical applicability.

Absorptiometry, Photon↗