UMLS:C0016382 - FACTA Search

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Query: UMLS:C0016382 (flushing)
6,387 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies have suggested that a cationic bactericidal/permeability-increasing protein (BPI) present in both rabbit and human polymorphonuclear leukocytes is the principal O2-independent bactericidal agent of these cells toward several strains of Escherichia coli and Salmonella typhimurium (1978. J. Biol. Chem. 253: 2664--2672; 1979. J. Biol. Chem. 254: 11000--11009). To further evaluate the possible role of this protein in the killing of gram-negative bacteria by polymorphonuclear leukocytes, we have measured the bactericidal activity of intact rabbit peritoneal exudate leukocytes under aerobic or anaerobic conditions and of intact human leukocytes from a patient with chronic granulomatous disease. Anaerobic conditions were created by flushing the cells under a nitrogen stream. Effective removal of oxygen was demonstrated by the inability of nitrogen-flushed leukocytes to mount a respiratory burst (measured as increased conversion of 1-[14C]glucose leads to 14CO2 or by superoxide production) during bacterial ingestion. At a bacteria/leukocyte ratio of 10:1, killing of gram-positive, BPI-resistant, Staphylococcus epidermidis is markedly impaired in the absence of oxygen (76.4 +/- 3.3% killing in room air, 29.2 +/- 8.2% killing in nitrogen). Essentially all increased bacterial survival is intracellular. In contrast, both a nonopsonized rough strain (MR-10) and an opsonized smooth strain (MS) of S. typhimurium 395 are killed equally well in room air and nitrogen. A maximum of 70--80 MR-10 and 30--40 MS are killed per leukocyte either in the presence or absence of oxygen. There is no intracellular bacterial survival in either condition indicating that intracellular O2-independent bactericidal system(s) of rabbit polymorphonuclear leukocytes can at least match the leukocyte's ingestive capacity. Whole homogenates and crude acid extracts manifest similar bactericidal capacity toward S. typhimurium 395. This activity can be accounted for by the BPI content of these cell fractions and is virtually eliminated by immune (anti-BPI), but not by preimmune goat IgG-rich fractions. Opsonization of smooth MS, required for bacterial killing by intact leukocytes, does not alter bacterial sensitivity to BPI in crude or purified form. Leukocytes of a patient with chronic granulomatous disease killed ingested S. typhimurium 396 MS nearly as well as did normal leukocytes. The bactericidal activity toward E. coli (J5) of crude acid extracts of the CGD and normal human leukocytes was virtually the same and was nearly completely inhibited by anti-BPI IgG-rich fractions, but not by preimmune IgG-rich fractions. These findings suggest that the killing of gram-negative bacteria such as S. typhimurium by intact polymorphonuclear leukocytes may also be attributed to the action of BPI.
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PMID:Killing of gram-negative bacteria by polymorphonuclear leukocytes: role of an O2-independent bactericidal system. 704 58

Some data on the synthesis and characterization of poly(HEMA-MAC) and its applications for fertility control are presented. This new technique involves the use of the polymer, which when injected into the vas deferens lowers the pH sufficiently so as to kill the spermatozoa passing through. The polymer provides an acidic environment for a prolonged time and slowly erodes. The fertility may be restored after complete solubility of the polymer itself over a period of time or by flushing it with a suitable solvent. It is a nonsurgical, nonocclusive, and reversible method of male contraception. In regard to the experimental procedure, copolymerization of HEMA with MAC (35% by weight) in methanol was carried out in a nitrogen atmosphere in glass ampules. Irradiation was performed in a cobalt-60 radiation chamber. All the samples were irradiated at a dose rate of 130 rad/s for a total dose of 0.936 Mrad at room temperature. For studying the spermicidal actions of the copolymer, epididymal fluid from the male rat was collected, diluted 1:10 with Ringer-fructose buffer and microscopically examined. Small swollen pieces of poly(HEMA-MAC) copolymer as well as poly(HEMA) homopolymer were then added to the epididymal fluid and the effect on the spermatozoa was noted. The spermicidal action "in vitro" was indicated by the loss of motility of the spermatozoa immediately on coming in contact with the poly(HEMA-MAC). The spermatozoa remained immotile even after the removal of the copolymer, indicating that they were dead. The polymer treated spermatozoa did not take up any supravital stain confirming that they were killed. This effect was absent only when poly(HEMA) was used. These results clearly show that the spermicidal activity is mainly due to the carboxylic groups of MAC. Possibly the low pH environment due to the ionization of carboxylic groups is responsible for killing the spermatozoa. For all the experiments the injection of the polymeric solution into the vas deferens was given only by exposing the vas deferens, but it is reported that in humans injection into the scrotal wall is possible. The new technique has all the characteristics which can lead to an ideal contraceptive method. Preliminary results of "in vitro" experiments on human spermatozoa with these hydrogels are encouraging.
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PMID:Novel mode of contraception using polymeric hydrogels. I. 705 60

The effect of loud sound on the perilymphatic oxygen tension was studied in anesthetized guinea pigs. Pure tone (4 kHz) and broad-band noise were given at 85-130 dB SPL for 3-8 min. No effects were seen either in the animals exposed to pure tone or in the animals exposed to 85 dB broad-band noise. In the animals exposed to noise at 130 dB SPL both increases and decreases of perilymphatic oxygen were measured but the changes were only of about 12% or less. The response to anoxia was normal. In animals with hypotension ( less than 8 kPa) the perilymphatic PO2 fluctuated with the blood pressure. When the sound was delivered directly into the opened bulla the measured PO2 dropped immediately but was found to be caused by the cooling effect of an air current produced by the noise. Flushing the opened bulla with nitrogen, air or oxygen caused the same temperature-induced drop of measured PO2. The results and the artifacts are discussed.
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PMID:Does loud sound influence the intracochlear oxygen tension? 730 43

We describe herein a new experimental model in which an isolated rat lung was ventilated with a mixture of 95% nitrogen and 5% carbon dioxide to decrease the oxygen and increase the carbon dioxide in the perfused blood to create and maintain a gas composition similar to that of venous blood. By utilizing this system as a "deoxygenator," pulmonary functions, including gas exchange, could be measured for at least 60 min in isolated and preserved lungs on reperfusion. When the effects of glucose in the flushing and storage solution were examined, 5 mM glucose in the solution resulted in better preservation of the lung, as shown by a higher uptake of oxygen and a lower intratracheal pressure, than when no glucose was given. However, the presence of 50 mM glucose was not beneficial, but rather increased the wet/dry weight ratio of the tissue.
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PMID:Effects of glucose on rat lung preservation: report of a study conducted on an isolated lung reperfusion model utilizing. Another isolated lung as a "deoxygenator". 757 63

Atmospheres containing concentrations of CO2 as low as 20% (balance nitrogen) inhibited the growth of Pseudomonas fluorescens and Pseudomonas putida on the surface of buffered Brain Heart Infusion agar plates, pH 6.8, incubated at 5 or 15 degrees C in flexible packages. The modified atmospheres decreased the growth rates and reduced the populations attained at the end of the exponential phase of growth, but had no substantial effect on the lag phase. P. fluorescens was less tolerant of CO2 than P. putida. The inhibitory effect of CO2 increased with its concentration and inhibition was greater at 5 than at 15 degrees C. Growth occurred in packages flushed with 20, 40 and 100% CO2 and 100% N2 at 15 degrees C and 20 and 40% CO2 and 100% N2 at 5 degrees C. The residual O2 concentration in the packages after flushing was 0.2-0.5%. Storage of pseudomonads in CO2 under conditions that prevented growth (e.g., 100% CO2, 5 degrees C) did not cause substantial loss of viability. There was no detectable residual effect of CO2. If cultures were incubated in air after storage for up to 70 days in CO2-containing atmospheres which prevented growth, the subsequent growth curve did not differ noticeably from that observed when plates were incubated in air immediately after inoculation. When cultures in the exponential or stationary phases of growth in modified atmospheres were transferred to air, growth rates increased quickly to rates similar to those observed in air and the final populations observed in air were attained. A reduction in the pH of the medium to 5.5 substantially increased the inhibitory effect of CO2. At 5 degrees C and pH 5.5, substantial growth of P. fluorescens was not observed in any of the CO2 concentrations tested, nor in 40 or 100% CO2 for P. putida.
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PMID:The effects of modified atmospheres on the growth of psychrotrophic pseudomonads on a surface in a model system. 826 59

A thin-layer gas-solution microcalorimeter has been developed to study the binding reactions of gaseous ligands with ligand binding macromolecules in solution. Gas partial pressures are accurately changed logarithmically by means of a precision dilution valve allowing for the stepwise determination of reaction heats. Heat binding curves are constructed in which the enthalpy per mole of reaction site is plotted versus the logarithm of the ligand activity. MicroJoule sensitivity is achieved through closed loop proportion computer control and precisely twinned highly isolated sample and reference geometry. The sample, typically 50 microliters and 1 to 4 mM heme protein, is placed on a filter paper membrane which acts as a matrix of support. This orientation allows for the rapid equilibrium of reacting ligand in approximately 10 min while not significantly altering the ligand activity. The system is controlled by computer measuring the heat of reaction as the partial pressure is changed automatically, typically by flushing the system with reacting ligand then reducing its partial pressure logarithmically with a nonreacting gas such as nitrogen. Binding curves can be constructed with as little as 20 nmol of oxygen binding sites.
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PMID:A thin-layer gas-solution microcalorimeter for the determination of heat binding curves. 846 49

The stability of a preservative-free morphine chloride solution for intravenous or intrathecal use manufactured at a concentration of 40 mg/ml, near the solubility limit in water, was studied. The influence of heat and oxygen on morphine content was measured with and without autoclaving, and after additional thermal and oxidative stress. The morphine injection was stable during steam sterilization at 121 degrees C for up to 180 min if the solution was adjusted to a pH of 3.2 and if oxygen was eliminated by saturating the solution and flushing the vial with nitrogen before sealing. By adding an oxidizing agent (200 microliters H2O2 3% per 20 ml vial) before 15 min of sterilization, a decomposition of approximately 20% of morphine resulted when compared to oxygen-free control samples (P < 0.01, n = 3) High-performance liquid chromatography with UV detection (HPLC) and direct UV spectroscopy (UV) (the latter available in most hospital pharmacies for analytical purposes) were compared for specificity, precision and appropriateness for content and stability assessment of morphine solutions. UV could only be used for quantification of undecomposed morphine. Morphine degradation products of stressed solutions interfered with the direct UV assay of morphine at 286 nm, whereas these interfering components were separated by the ion-pair reversed-phase HPLC used. The results demonstrate that even in the absence of stabilizers, morphine chloride solutions may safely be sterilized for 15 min at 121 degrees C. The HPLC method was shown to be sufficiently sensitive and specific for quality control and stability assessment of morphine preparations, and, therefore, appropriate for the validation of the manufacture of morphine injection solutions in hospital pharmacies, where morphine solutions are manufactured in special strengths and volumes for individual patients' needs.
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PMID:Stability of high-dose morphine chloride injection upon heat sterilization: comparison of UV-spectroscopy and HPLC. 880 42

The authors developed a new apparatus for extracting nitrogen or other inert gases from blood by flushing (sparging) the specimen with another gas. To investigate the utility of the new methodology, the apparatus was used in conjunction with a mass spectrometer to measure the blood N2 content of healthy normobaric, non-smoking, adult volunteers; the mean was found to be 11.7 microliters/ml +/- 0.9 microliter. This compares closely with values cited in the literature. The within-subject variation for repeat samples taken several weeks apart was significantly (P < 0.003) less than the variation between different subjects, suggesting that there may be true differences in N2 content between different individuals. These data must be considered preliminary, a larger study is needed to investigate population differences in detail. The advantages of the new method are discussed.
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PMID:A new method for measuring nitrogen and gases in blood. 898 54

The total elimination of air represents a serious hurdle in modified atmosphere packaging of bakery products, due both to the high spin-rates of the packaging lines and, particularly, to the typical texture of bakery products which retain large quantities of air inside their porous structure. Simulating the gas-flushing modified atmosphere packaging with laboratory equipment and measuring the oxygen concentration directly inside bread rolls, by means of a gas analyser connected with the internal portion, it was possible to follow the rate of atmosphere substitution, evaluating the effects of different baking treatments (7, 12 and 23 min at 230 degrees C) and the role played by different gases (nitrogen, argon, helium, nitrous oxide and carbon dioxide). The oxygen content inside the products, plotted versus time, led to typical logistic 'dose-response' curves which made it possible to forecast the time needed to reach established values of residual oxygen concentration and to emphasize the effects of the different conditions used. The gas properties particularly affected the rate of oxygen substitution and the less water-soluble was the gas, the faster was the oxygen reduction; the larger was the gas molecule, the slower was the process. Also baking time was shown to have, to a different extent, some measurable effects on the rate of oxygen substitution and hence, its optimization as well as the choice of gas mixture can contribute to improve modified atmosphere packaging of bakery products.
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PMID:Minimizing the residual oxygen in modified atmosphere packaging of bakery products. 937 39

The influence of molecular oxygen and oxygen radicals on the photoreactivity of the antimalarial drug primaquine (PQ) has been investigated. Oxygen is directly involved in photodecomposition of the drug. Flushing with helium gas prior to and during irradiation to suppress the oxygen level of the medium, retards the degradation rate of PQ (followed by HPLC) and leads to the formation of only two degradation products (identified by MS) compared to eight main- and several minor products under normal atmospheric conditions. Flushing with oxygen gas prior to and during irradiation to increase the oxygen content of the medium accelerates the degradation rate of PQ. PQ produces oxygen radicals (hydroxyl and superoxide) during photolysis, while the photoproducts of PQ seem likely to induce singlet oxygen formation (detected by addition of radical scavengers). Sensitization reactions involving singlet oxygen lead to decomposition of PQ (followed by HPLC). On the basis of our results, photochemical reaction mechanisms of PQ are postulated and discussed. At physiological conditions (aqueous, neutral pH, oxygen rich) PQ has a large potential to decompose after light absorption. The photoreaction seems to be initiated at the quinoline nitrogen. The ability to form an intramolecular hydrogen bond seems to be essential for the luminescence properties of the drug. Phosphorescence lifetime of PQ is about 5 microseconds. Fast chemical reactions may occur from the short-lived triplet state of the drug, but the excited compound can diffuse only a limited distance prior to deexcitation. This can be important concerning light-induced adverse effects which may appear after medication with PQ.
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PMID:Photoreactivity of biologically active compounds, XIV: influence of oxygen on light induced reactions of primaquine. 954 Jan 7

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