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At least 379 records · Page 21Linked to original sources
PubMed2006

The role of antioxidant supplementation in occupational exposure to waste anaesthetic gases.

OBJECTIVES: Although the genotoxicity related to waste anaesthetic gases is controversial, a consistent number of observations have provided evidence for an increased level of DNA strand breaks. The goal of the research was to investigate this hypothesis and estimate the genoprotective role of antioxidant supplementation in technical anaesthesiology staff working in operating theatres. METHODS: Heparinized venous blood samples were collected from 17 exposed technical anaesthesiology staff (mean age 34.3 +/- 3.5 years) and non-exposed control group (mean age 32.2 +/- 3.4 years) and examined in the alkaline comet assay for DNA strand breakage. Vitamin E (300 mg/day) plus vitamin C (500 mg/day) were supplemented to the technical anaesthesiology staff for 12 weeks and blood samples were retaken and evaluated by comet assay. RESULTS: The DNA breakage observed in the lymphocytes of the technical anaesthesiology staff was 21.5 +/- 5.0, as calculated by total comet score (TCS). This score was significantly higher (P<0.001) than in the controls (8.6 +/- 4.7) before antioxidant treatment. Supplementation of vitamins E plus C significantly (P<0.01) reduced the mean TCS as 14.2 +/- 6.1. CONCLUSION: The results of our study indicate that occupational exposure to anaesthetic gases induces oxidative DNA damage. Supplementation of the diet for 12 weeks with vitamin C and vitamin E resulted in a significant decrease in the DNA damage.

Adult↗
PubMed1998

Manoeuvres to elevate mean airway pressure, effects on blood gases and lung function in children with and without pulmonary pathology.

UNLABELLED: During mechanical ventilation, mean airway pressure (MAP) can be increased by a variety of manoeuvres, for example increasing inspiratory time or elevating the positive end expiratory pressure (PEEP). It seemed likely that the effect on blood gases and lung function of a particular manoeuvre to increase MAP would be influenced by the presence of respiratory pathology and thus the manoeuvre best at improving respiratory status in children with an abnormal chest radiograph appearance would differ from that most efficacious in children without such a problem. The aim of this study was to test that hypothesis. Twenty-two children, median age 15 months (range 2.5 weeks-10 years) were examined. Group 1 (n = 10) had no chest radiograph abnormalities and group 2 (n = 12) lobar collapse and/or consolidation. The patients were studied at baseline settings and at an elevated MAP resulting from (in random order) an increase in inspiratory time (T1), pressure PEEP or peak inspiratory pressure (PIP). In group 1, elevating PIP improved oxygenation and carbon dioxide elimination (P < 0.01) and prolonging T1 improved oxygenation (P < 0.05). In group 2, only raising PEEP significantly improved oxygenation (P < 0.01), but this was associated with carbon dioxide retention (P < 0.01). CONCLUSION: The presence of lung pathology does influence which manoeuvre should be used to elevate MAP to improve blood gases in the paediatric population.

Airway Resistance↗
PubMed2003

Influence of different gases used for laparoscopy (helium, carbon dioxide, room air, xenon) on tumor volume, proliferation, and apoptosis.

BACKGROUND: Previous reports suggest that helium pneumoperitoneum used for laparoscopic surgery suppresses postoperative tumor growth. The present study was designed to determine the effects of gases used in laparoscopy on tumor volume, proliferation, and apoptosis in rats with implanted malignoma. METHODS: In 36 rats Morris hepatoma 3294A cells were implanted intrahepatically. Then, after 5 days, they underwent laparoscopy using helium ( n = 7), CO(2) ( n = 7), room air ( n = 7), or xenon ( n = 8). One group received anesthesia only ( n = 7). Rats were killed 10 days after implantation to assess tumor volume, proliferation, and apoptosis. RESULTS: Helium pneumoperitoneum caused a significant smaller tumor volume compared to other groups (Kruskal-Wallis test: p = 0.001; median tumor volume: control: 44 mm3; helium: 19 mm3). There was no significant difference in tumor cell proliferation (PCNA) and apoptosis (TUNEL reaction) between the groups. CONCLUSIONS: There was a significant decrease of tumor volume using helium pneumoperitoneum compared to the other gases, but no decreased tumor cell proliferation or increased tumor cell apoptosis.

Air↗
PubMed2004

Influence of different gases used for laparoscopy (helium, carbon dioxide, room air, and xenon) on tumor volume, histomorphology, and leukocyte-tumor-endothelium interaction in intravital microscopy.

BACKGROUND: Previous studies indicate that helium pneumoperitoneum used for laparoscopic surgery suppresses whereas carbon dioxide pneumoperitoneum increases postoperative tumor growth. The pathomechanisms of decreased tumor growth by helium are unknown. This study was designed to examine the effect of the gases helium, carbon dioxide (CO(2)), and air, and xenon, which can be used to induce pneumoperitoneum in laparoscopy on tumor volume, histomorphology, and leukocyte-endothelium interaction measured by intravital microscopy in rats with implanted liver malignoma (Morris hepatoma 3924A). METHODS: In 46 rats, Morris hepatoma 3294A cells were implanted intrahepatically. After implantation, rats were randomized into two main groups. In the first main group, 10 animals were prepared for examination of leukocyte-endothelium interaction by intravital video microscopy and were randomized into two groups. Five days after implantation they underwent laparoscopy using either helium (n = 5) or CO(2) (n = 5). Ten days after implantation the rats underwent intravital video microscopy to assess leukocyte-endothelium interaction in the tumor and liver vessels. In the second main group 36 rats were prepared for examination of tumor volume arid histomorphology. They were randomized into five groups. Five days after implantation they underwent laparoscopy using helium (n = 7), carbon dioxide (n = 7), room air (n = 7), or xenon (n = 8). The control group (n = 7) received anesthesia only. Rats were killed 10 days after tumor implantation to assess tumor volume and histomorphology. RESULTS: Compared to the control group or groups that received CO(2), room air, or xenon for pneumoperitoneum, the establishment of helium pneumoperitoneum caused a significantly smaller tumor volume (Kruskal-Wallis test, p = 0.001; median tumor-volume: control group, 44 mm(3); helium 19 mm(3)). There was no significant difference in histomorphology between the groups. There was only a statistically significant difference in the development of central tumor necrosis in accordance to tumor volume (Mann-Whitney test, p = 0.03). In the tumor samples, roller counts were statistically significantly higher in the helium group compared to the CO(2) group (p = 0.04). For sticker counts, no statistically significant effects due to liver/tumor (p = 0.13) or treatment (p = 0.48) were observed. CONCLUSIONS: There was a significant decrease in tumor volume using helium pneumoperitoneum for laparoscopy compared to the other gases. Here, we demonstrate that suppression of tumor growth is not due to variation of histomorphology. It seems that helium pneumoperitoneum effects a higher leukocyte-endothelium interaction and thereby a higher immune activation. This could be one explanation for the statistically significantly smaller tumor volume after laparoscopy with helium compared to laparoscopy with CO(2).

Air↗
PubMed2001

Helium and other alternative insufflation gases for laparoscopy.

BACKGROUND: Carbon dioxide (CO(2)) is currently the insufflation gas of choice for laparoscopy. It fulfills most of the requirements for an ideal insufflation gas, being colorless, noninflammable, and rapidly excreted from the circulation. However, its use is associated with adverse cardiorespiratory effects, especially in patients with preexisting cardiorespiratory compromise. METHODS: The descriptive review of relevant literature, moreover, has been proposed that it increases the incidence of port site (wound) metastases from abdominal cancers when used during oncological surgery. In addition, it may cause postoperative pain due to peritoneal irritation, and its use is associated with physiological and immunological impairment. Hence, there is scope for the investigation of alternative insufflation gases. Other possibilities include gasless laparoscopy, helium, nitrous oxide, (N(2)O), and argon. Helium insufflation has been used extensively in animal models but only to a limited extent in humans. In experimental studies, it has been shown to produce fewer changes in cardiorespiratory and intraperitoneal immunological status than CO(2) insufflation, and its use is associated with less spread of tumors to port sites in a variety of small animal tumor models. However, helium also has the potential for some adverse effects. Helium pneumothorax probably resolves more slowly than CO(2) pneumothorax, and helium gas embolism is tolerated poorly in animal models. The clinical significance of these potential problems has yet to be determined. CONCLUSIONS: Although the use of alternative gases appears to be promising, further evaluation is needed within both clinical and laboratory settings before their routine clinical use can be supported.

Abdominal Neoplasms↗
PubMed2001

Impact of different gases and pneumoperitoneum pressures on tumor growth during laparoscopy in a rat model.

BACKGROUND: The influence on intraperitoneal tumor growth of the choice of gas and pneumoperitoneum pressure during laparoscopy is still unknown. This study compared tumor growth after laparoscopy with different gases and pneumoperitoneum pressures in an immunodeficient model. METHODS: In an initial experiment, 60 nude rats were randomly allocated to undergo laparoscopy at different pneumoperitoneum pressures (gasless, 4 mmHg, or 8 mm Hg.) In a second experiment, 23 nude rats were randomly allocated to undergo laparoscopy with different gases (carbon dioxide or helium). Surgery was carried out 7 days after intraperitoneal injection of IGR-OV1 cells. The rats were killed 7 days after surgery. Tumor growth was assessed by the weight of the omental metastasis. For statistical analysis, we used analysis of variance (ANOVA). RESULTS: Mean omental weight was similar for all groups, regardless of the pneumoperitoneum pressure (p = 0.86) or the type of gas (p = 0.80). CONCLUSION: Physical parameters of gas have a limited impact on tumor growth.

Animals↗
PubMed1980

Effects of gaseous anaesthetics and inert gases on the phase transition in smectic mesophases of dipalmitoyl phosphatidylcholine.

The phase transition in smectic mesophase of dipalmitoyl phosphatidyl-choline was studied under high pressures of helium (340 atm), nitrogen (340 atm), nitrous oxide (43 atm), cyclopropane (4.4 atm) and n-propane (8.2 atm), using a turbidimetric technique. Helium and nitrogen increased the transition temperature by 0.021 and 0.006 degree C/atm, respectively, compared with 0.024 degrees C/atm for hydrostatic pressure. Nitrous oxide reduced the transition by 0.58 degree C/atm. The hydrocarbon gases spread the transition width and lowered the transition temperature with increasing effect at higher doses. Comparisons with other membrane probes are made and the concentration of gases in the bilayer which lower the transition temperature by 1 degree C are estimated, in mol%: He, 10.2; N2, 13.2: N2O, 9.04; n-C3H8, 6.3 and cyclopropane, 12.8.

Anesthetics↗
PubMed1994

An investigation into the batch killing of turkeys in their transport containers using mixtures of gases.

This study was carried out under commercial conditions to investigate the feasibility of killing turkeys while they were still in their transport containers, with a mixture of gases, and to compare the effects of this method and electrical stunning on the prevalence of carcase down-grading conditions and haemorrhages in the breast muscles. The results showed that turkeys could be readily killed while still in their transport containers by using either anoxia induced with 90 per cent argon in air or hypercapnic anoxia induced with a mixture of 30 per cent carbon dioxide and 60 per cent argon in air, and that the prevalence of carcase-downgrading conditions and haemorrhages in the breast muscles was lower after killing the turkey with the gases.

Abattoirs↗
PubMed1986

Effects of altering dead space volume on respiration and air sac gases in geese.

Dead space volume (VD) was altered in spontaneously breathing, anesthetized geese from values far above (about 115 ml) to those far below (about 3 ml) the normal VD (approximately 40 ml). Respiratory gases were measured in cranial (CrS) and caudal air sacs (CdS) and in blood. The major findings were as follows: Ventilation increased linearly with VD, by increases in tidal volume (VT) at constant breathing rate (fresp); effective parabronchial ventilation, (VT-VD) X fresp, remained constant and so did arterial blood gases. No changes occurred in CrS gas composition. CdS PCO2 declined with decreasing VD, and the respiratory exchange ratio increased, reaching values above unity at the lowest VD. The gas composition in CrS, and particularly its relation to end-expired gas composition, is in agreement with current models of the gas flow pattern in the avian lung. The PCO2 values in CdS are higher than expected by simple models, e.g. by dead space re-inhalation. Neopulmonic gas exchange and incomplete gas mixing are suggested to contribute significantly to the gas composition of CdS.

Air Sacs↗
PubMed1992

Phrenicotomy in the rat: acute changes in blood gases, pH and body temperature.

Adult male rats were used to compare blood gases, pH and body temperature (Tb) before and after acute bilateral phrenicotomy. Under anaesthesia a femoral artery was catheterised and ties were placed round the phrenic nerves of seven rats (PNX group), while in five rats the ties were placed in the vicinity of the phrenic nerves (SHAM group). Twenty-four hours after surgery arterial blood samples were collected during quiet wakefulness (QW) and grooming (G), before and 1 h after the ties were pulled, and analysed for PO2, PCO2 and pH. No changes were detected in the SHAM samples taken before and after the ties were pulled. In the PNX group a significant decrease in Tb occurred (QW, 0.6 degrees C; G, 1.5 degrees C). Following PNX PaO2 decreased by 11.2 mmHg (QW) and 10.0 mmHg (G); PaCO2 increased by 2.6 mmHg (QW) and 2.4 mmHg (G) and pH fell by 0.04 (QW) and 0.03 (G). All changes except in PaCO2 (QW) were significant. It is concluded that the changes in Tb, blood gases and pH which follow phrenicotomy in the rat are due to an increase in dead space ventilation (VD) and a small reduction in alveolar ventilation (VA) associated with a faster, shallower pattern of breathing.

Animals↗
PubMed1994

Effects of elevated pressures of inert gases on cytosolic free Ca2+ of cultured human neuroblastoma cells stimulated with carbachol: relevance to high pressure neurological syndrome.

Suspended cells of the human neuroblastoma line SK-N-SH were exposed to elevated pressures of non-narcotic helium (He) and the narcotic gases nitrogen (N2), and argon (Ar) and stimulated with carbachol. He, 18 and 36 atmospheres absolute (ATA), equivalent to 544 and 1120 feet of seawater, potentiated the increase in [Ca2+]i induced by carbachol, as measured by Fura-2. Carbachol-stimulated increases in [Ca2+]i were not significantly altered from values in 1 ATA air by either N2 or Ar at the same pressures. The response to carbachol of cells exposed to 36 ATA of He and slowly decompressed to 1 ATA was indistinguishable from that of cells never exposed to pressure. Thus this pressure-potentiated increase in [Ca2+]i is compatible with excitation, is reversible and is not elicited by narcotic gases. It was observed, moreover, at pressures encountered by commercial deep-sea divers. The High Pressure Neurological Syndrome (HPNS) encountered by divers breathing He/O2 mixtures at high pressures, and its known antagonism by N2, may be due in part to effects on neuronal [Ca2+]i levels since an increase in these would most likely result in an excitatory response.

Argon↗
PubMed1990

A small-scale controlled environment chamber for the investigation of the effects of pollutant gases on plants growing at cool or sub-zero temperature.

A new, small-scale controlled environment plant growth chamber is described, which permits accurately controlled temperatures from ambient (c. 20 degrees C) down to -5 degrees C in the day or -15 degrees C at night. The system also allows controlled injection of pollutant gases. The chamber is based on a modified commercial chest freezer with temperature control achieved through by-passing the cooling coils in the inner walls of the freezer. This by-pass is controlled by a BBC microcomputer which gives nominal temperature control to 0.1 degrees C over definable diurnal temperature profiles. Photoperiod is also controlled by the microcomputer. The chamber forms a virtually closed system to which pollutant gases are added by injection from low concentration cylinders, regulated using mass flow controllers. The accuracy with which pollutant concentrations are controlled is increased by filtration of the air-stream after passing over the experimental plants: i.e. a 'single-pass' system is adopted. In operation air temperatures across the chambers are controlled to within 1-1.5 degrees C of the pre-set value over the range 25 to -10 degrees C. Leaf temperatures are 2.5-3.0 degrees C above air temperatures during the day, with a total energy input of c. 180 Wm(-2) from two 400 W metal halide lamps. The lamps provide a photon fluence rate of 270+/-30 micromol quanta PAR m(-2) s(-1) at plant height. During the dark, leaf temperatures deviate less than 1.0 degrees C from air temperature. Soil temperatures are controlled separately from air temperature and are held above zero at all times. To date, fumigation, with NO(2) and SO(2) has been confined to the daytime. At pre-set concentrations of 20 nl litre(-1) variations during fumigation were less than 2.0-2.5 nl litre(-1) and 0.5 nl litre(-1), respectively.

Journal Article↗
PubMed1988

Biochemical effects of combined gases of nitrogen dioxide and ozone. II. Species differences in lipid peroxides and antioxidative protective enzymes in the lungs.

Changes in lipid peroxide (thiobarbituric acid reactant) levels, in the content of non-protein sulfhydryls (NPSH) and total proteins, and in the activities of antioxidative protective enzymes were examined in the lungs of four animal species exposed to a mixture of NO2 and O3 for 2 weeks. Male mice, hamsters, rats and guinea pigs were used. Thiobarbituric acid (TBA) reactant levels were increased significantly in the lungs of mice and guinea pigs, but not in hamsters and rats. NPSH contents were increased markedly in hamsters, mice and rats, but not in guinea pigs. The activities of antioxidative protective enzymes also changed with the exposure. The most characteristic change was the significant increase in glutathione peroxidase (GPx-H2O2) activity in hamsters and rats - species which did not exhibit increases in their TBA reactant levels. The increase in this enzyme activity in mice was significant, but not very large. Furthermore, guinea pigs were genetically deficient in this enzyme, and the increase in glycolytic enzymes for regenerating NADPH was also lowest in guinea pigs. The glutathione S-transferase (GSH-Tase) activity in mice and guinea pigs was decreased by exposure to the combined gases. These results suggest that the increases in lipid peroxide levels in mice and guinea pigs may be due to a lesser ability to regenerate protective reducing substances, such as NPSH and NADPH, than that of hamsters and rats. Induction of protective enzyme activities on exposure to the combined gases was also poor in mice and guinea pigs.

Animals↗
PubMed1988

Studies on asphyxia: on the changes of the alveolar walls of rats in the hypoxic state. II. The hypoxic state produced by carbon dioxide and methane gases.

Experimental studies were presented here concerning death by asphyxia due to the inhalation of carbon dioxide and methane gases. The morphological changes were almost the same as those demonstrated in our previous report. The authors concluded that the morphological changes in the lung tissue were not attributable to the chemical specificity of gases used in the experiment but to the decrease of oxygen.

Animals↗
PubMed1988

The effect of oxidant gases on membrane fluidity and function in pulmonary endothelial cells.

Free radicals and oxidant gases, such as oxygen (O2) and nitrogen dioxide (NO2), are injurious to mammalian lung cells. One of the postulated mechanisms for the cellular injury associated with these gases and free radicals involves peroxidative cleavage of membrane lipids. We have hypothesized that oxidant-related alterations in membrane lipids may result in disordering of the plasma membrane lipid bilayer, leading to derangements in membrane-dependent functions. To test this hypothesis, we examined the effect of exposure to high partial pressures of O2 or NO2 on the physical state and function of pulmonary endothelial cell plasma membranes. Both hyperoxia (95% O2 at 1 ATA) and NO2 exposure (5 ppm) caused early and significant decreases in fluidity in the hydrophobic interior of the plasma membrane lipid bilayer and subsequent depressions in plasma membrane-dependent transport of 5-hydroxytryptamine. Lipid domains at the surface of pulmonary endothelial cell plasma membranes are more susceptible to NO2-induced injury than to hyperoxic injury. Alterations in the fluidity of these more superficial domains are associated with derangements in surface dependent functions, such as receptor-ligand interaction. These results support our hypothesis and advance our understanding of how the chemical events of free radical injury associated with high O2 and NO2 tensions are translated into functional manifestations of O2 and NO2-induced cellular injury.

Endothelium↗
PubMed1996

Cord serum erythropoietin in 90 healthy newborn term infants: relationship to blood gases and iron status markers.

In this study, we examined the cord serum erythropoietin (EPO) level in newborn infants in relation to venous cord blood gases and iron status markers (cord serum ferritin, cord serum transferrin saturation). The subjects were 90 healthy newborn term infants with a normal birth and 90 healthy women with an uncomplicated pregnancy and delivery. Within 14-18 weeks of gestation, 47 prospective mothers, allocated at random, received tablets containing 66 mg ferrous iron daily, and 43 received a placebo. Serum EPO was measured in women prior to delivery. Serum EPO, serum ferritin and serum transferrin saturation were analyzed in cord blood from the newborn. Blood gases (PO2, PCO2 and standard HCO3, PH) were measured in venous cord blood and Apgar scores were recorded. The cord serum EPO level in the newborn was not significantly affected by the iron supplementation to the mothers. In the entire series, the geometric mean cord serum EPO was 36 U/I, (median 32 U/I, 5-95% 16-150, range 12-380). There was no correlation between cord serum EPO and APgar score, cord blood PO2, PCO2, standard HCO3 and pH. In the newborn of placebo-treated mothers, log cord serum EPO was inversely correlated with log cord serum ferritin (r = -0.54, P < 0.0002) and cord serum transferrin saturation (r = -0.39, P < 0.011), suggesting that iron deficiency may occur in this newborn group.

Apgar Score↗
PubMed2005

Identification of biogenic dimethyl selenodisulfide in the headspace gases above genetically modified Escherichia coli.

Escherichia coli JM109 cells were modified to express the genes encoded in a 3.8-kb chromosomal DNA fragment from a metalloid-resistant thermophile, Geobacillus stearothermophilus V. Manual headspace extraction was used to collect the gases for gas chromatography with fluorine-induced sulfur chemiluminescence analysis while solid-phase microextraction was used for sample collection in gas chromatography/mass spectrometry (GC/MS) analysis. When grown in the presence of selenate or selenite, these bacteria produced both organo-sulfur and organo-selenium in the headspace gases above the cultures. Organo-sulfur compounds detected were methanethiol, dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide. Organo-selenium compounds detected were dimethyl selenide and dimethyl diselenide. Two mixed sulfur-selenium compounds, dimethyl selenenyl sulfide and a chromatographically late-eluting compound, were detected. Dimethyl selenodisulfide, CH(3)SeSSCH(3), and dimethyl bis(thio)selenide, CH(3)SSeSCH(3), were synthesized and analyzed by GC/MS and fluorine-induced chemiluminescence to determine which corresponded to the late-eluting compound that was bacterially produced. CH(3)SeSSCH(3) was positively identified as the compound detected in bacterial headspace above Se-amended cultures. Using GC retention times, the boiling point of CH(3)SeSSCH(3) was estimated to be approximately 192 degrees C. This is the first report of CH(3)SeSSCH(3) produced by bacterial cultures.

Escherichia coli↗
PubMed2004

Studies on the positive-ion mass spectra from atmospheric pressure chemical ionization of gases and solvents used in liquid chromatography and direct liquid injection.

Detailed studies have been made using different source gases and solvents in a Micromass Quattro mass spectrometer under positive ion atmospheric pressure chemical ionization conditions. The major background ions from nitrogen, air, or carbon dioxide were investigated by tandem mass spectrometry, followed by similar studies on solvents commonly employed in normal- and reversed-phase high-performance liquid chromatography, namely, water-acetonitrile, acetonitrile, and dichloromethane, with nitrogen, air, or carbon dioxide; hydrocarbon solvents were studied using nitrogen. Spectra were interpreted in terms of the gases, solvents, and their impurities. The acetonitrile spectra provided clear evidence for both charge exchange and proton transfer, the former being facilitated by the introduction of some air into a flow of nitrogen. Radical cations of acetonitrile dimers, trimers, and tetramers were observed, as were protonated dimer and trimer species. Examination of the analytical response of four polycyclic aromatic hydrocarbons in various hydrocarbon solvents, with nitrogen gas, showed that the sensitivity of detection for an analyte and its ionization mechanism are dependent on both the analyte structure and the solvent, with pyrene showing the highest sensitivity, phenanthrene and fluorene being intermediate, and naphthalene having the lowest sensitivity. The degree of protonation followed the same trend. Signal intensity and degree of protonation were dependent on the alkane solvent used, with isooctane providing the best overall sensitivity for the sum of protonated molecules and molecular ions. The ions observed in these studies appeared to be the most stable ions formed under equilibrium conditions in the source.

Journal Article↗