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Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently, a forced-air-ventilated micro-isolation system (FVMIS) has been recognized to accurately maintain microenvironmental conditions inside cages, but the details of the relationship between the concentrations of carbon dioxide (CO2) and oxygen (O2) and the air change rate inside the cages have never been reported. In this study, the proper intra-cage air change rate was examined based on the CO2 concentration and O2 concentration inside the cages measured by changing the ventilation volume inside the closed cages of the FVMIS while housing animals. In the experiments, three 8-week-old Wistar strain male rats weighing 303 g on average were housed in each FVMIS cage (capacity: 0.0223 m3), and the temperature, relative humidity, CO2 concentration and O2 concentration were measured when the air change rate inside the cages was varied from 10 air changes per hour (ACH) to 120 ACH. It proved that the CO2 concentration in the FVMIS cages decreased uniformly with the increase in the air change rate. As a result, 60 ACH was required to maintain the CO2 concentration level inside the FVMIS cages equivalent to or less than that in the conventional housing. Otherwise, when based on the O2 concentration, 50 ACH was required. In consideration of these results and others based on ventilation, airflow, temperature and the ammonia concentration reported previously, we concluded that the proper air change rate inside the FVMIS cages should be approximately 60 ACH.
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PMID:Intra-cage air change rate on forced-air-ventilated micro-isolation system--environment within cages: carbon dioxide and oxygen concentration. 935 32

We have examined the reactions of peroxynitrite with short-chain aliphatic aldehydes to model the reaction of the peroxynitrite anion (ONOO-) with CO2. Aldehydes, like CO2, react rapidly with peroxynitrite and catalyze its decomposition. The pH dependence of the reaction is consistent with the addition of ONOO- (not ONOOH) to the carbonyl carbon atom of the free aldehyde forming a 1-hydroxyalkylperoxynitrite anion adduct (5), which structurally resembles the nitrosoperoxycarbonate adduct (1) formed from the reaction of ONOO- with CO2. Intermediate 5, or the secondary products derived from it, decays to give NO3- and regenerated aldehyde, with small but significant yields of H2O2, organic acids, and organic nitrates. In analogy with the peroxynitrite/CO2 system, it is suggested that 5 undergoes homolytic or heterolytic cleavage at the O-O bond, giving a caged radical pair [RCH(OH)O./ .NO2] (7) or intimate ion pair [RCH(OH)O -/+ NO2] (8). The radicals and ions in intermediates 7 and 8 can recombine within the solvent cage to form 1-hydroxyalkylnitrate [RCH(OH)ONO2] (6), which can then dissociate to give nitrate and regenerate the aldehyde. The aldehyde/ peroxynitrite adducts 5-8 mediate the oxidation of 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) but not the nitration of 4-hydroxyphenylacetate. The significance of these findings is discussed in relation to the mechanism(s) of the CO2-catalyzed isomerization of peroxynitrite to nitrate and biological nitrations involving peroxynitrite/CO2 adducts.
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PMID:Reactions of peroxynitrite with aldehydes as probes for the reactive intermediates responsible for biological nitration. 943 22

Impaired pulmonary mechanics can cause chest wall distortion (CWD) so that work of breathing is dissipated in deforming the rib cage. We hypothesized that respiratory mechanical unloading as a technique of assisted mechanical ventilation would reduce CWD in animals with injured lungs. We studied five piglets and five adult rabbits to test across different ages and chest configurations. As a result of intratracheal meconium instillation, lung compliance decreased from 21 (median; range 17-35) to 9.5 (6.7-14) mL/kPa/kg in rabbits and from 26 (18-31) to 7.9 (4.9-11) in piglets. Airway resistance increased from 5.0 (4.6-6.1) to 6.9 (5.8-7.9) kPa/L/s in rabbits only. Respiratory inductive plethysmography was used to measure the phase shift between the rib cage and abdominal compartment movements and the total compartmental displacement ratio. We aimed at unloading at least three-fourths of lung elastance in all animals and 2.0 kPa/L/s of resistance in rabbits. Elastic unloading decreased the phase shift in all but one animal. It reduced the total compartmental displacement ratio from 1.27 (1.14-3.73) to 1.16 (1.02-1.82) in piglets and from 1.77 (1.45-5.24) to 1.37 (1.11-4.78) in rabbits. The inspiratory rib cage expansion increased, whereas abdominal expansion did not. The tidal esophageal pressure deflection decreased. Tidal volume increased, whereas respiratory rate remained unaffected so that the partial pressure of arterial CO2 decreased. Resistive unloading as an adjunct to elastic unloading further reduced CWD and induced a more rapid, shallower breathing. We conclude that respiratory unloading as a mechanical support to spontaneous breathing reduces CWD. We speculate that the decrease in CWD increases ventilatory efficiency for a given diaphragmatic effort.
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PMID:Effects of respiratory mechanical unloading on thoracoabdominal motion in meconium-injured piglets and rabbits. 947 83

The aim of this experiment was to determine whether ventilatory measurements in adult restrained mice provide a valid assessment of chemosensitivity. We used whole-body plethysmography to compare breathing patterns in eight restrained and eight unrestrained outbred Swiss mice during air breathing, hypercapnia, and hypoxia. The mice in the restrained group were each placed in a loosely restraining wire-mesh cage. The unrestrained mice could move freely inside the plethysmograph. All the mice received three hypercapnic stimuli (8.5% CO2) and three hypoxic isocapnic stimuli (10% O2, 3.5% CO2). As compared to unrestrained mice, restrained mice had significantly lower breath durations (TT, 445+/-110 ms vs. 323+/-32 ms) and higher ventilation (VE) levels (15.7+/-2.6 microl/(sec x g) vs. 22.2+/-4.5 microl/(sec x g)), whereas no difference was observed for tidal volume (VT). The increases in frequency and ventilation from baseline to hypercapnia were not significantly different in restrained and unrestrained mice. The VE response to hypoxia was marginally higher in restrained mice. We conclude that chemosensitivity to hypercapnia, and to a lesser extent to hypoxia, can be measured in restrained adult mice, but that the baseline breathing pattern cannot.
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PMID:The effects of restraint on ventilatory responses to hypercapnia and hypoxia in adult mice. 971 5

While sustaining a load that leads to task failure, it is unclear whether diaphragmatic fatigue develops progressively or occurs only at task failure. We hypothesized that incremental loading produces a progressive decrease in diaphragmatic contractility ever before task failure. Ten subjects generated 60% of maximal transdiaphragmatic pressure (Pdimax) for 2 min, 4 min, and until task failure. Before loading, 20 min after each period of loading, and approximately 20 h after the last period of loading, Pdimax, nonpotentiated and potentiated Pdi twitch pressure (Pditw), and the pattern of respiratory muscle recruitment during a CO2 challenge were recorded. Sensation of inspiratory effort at the 4th min of the task-failure protocol was greater than at the same time in the preceding 4-min protocol. Surprisingly, potentiated Pditw and Pdimax were reduced after 2 min of loading and decreased further after 4 min of loading and after task failure; nonpotentiated Pditw was reduced after 4 min of loading and after task failure. The gastric pressure contribution to tidal breathing during a CO2 challenge decreased progressively in relation to duration of the preceding loading period, whereas expiratory muscle recruitment progressively increased. A rest period of approximately 20 h after task failure was not sufficient to normalize these alterations in respiratory muscle recruitment or fatigue-induced changes in diaphragmatic contractility. In conclusion, while sustaining a mechanical load, the diaphragm progressively fatigued, ever before task failure, and when challenged the rib cage-to-diaphragmatic contribution to tidal breathing and recruitment of the expiratory muscles increased pari passu with duration of the preceding loading.
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PMID:Does resistive loading decrease diaphragmatic contractility before task failure? 972 89

Rapid eye movements during rapid-eye-movement (REM) sleep are associated with rapid, shallow breathing. We wanted to know whether this effect persisted during increased respiratory drive by CO2. In eight healthy subjects, we recorded electroencephalographic, electrooculographic, and electromyographic signals, ventilation, and end-tidal PCO2 during the night. Inspiratory PCO2 was changed to increase end-tidal PCO2 by 3 and 6 Torr. During normocapnia, rapid eye movements were associated with a decrease in total breath time by -0.71 +/- 0.19 (SE) s (P < 0.05) because of shortened expiratory time (-0.52 +/- 0.08 s, P < 0.001) and with a reduced tidal volume (-89 +/- 27 ml, P < 0.05) because of decreased rib cage contribution (-75 +/- 18 ml, P < 0.05). Abdominal (-11 +/- 16 ml, P = 0.52) and minute ventilation (-0.09 +/- 0.21 ml/min, P = 0.66) did not change. In hypercapnia, however, rapid eye movements were associated with a further shortening of total breath time. Abdominal breathing was also inhibited (-79 +/- 23 ml, P < 0.05), leading to a stronger inhibition of tidal volume and minute ventilation (-1.84 +/- 0.54 l/min, P < 0.05). We conclude that REM-associated respiratory changes are even more pronounced during hypercapnia because of additional inhibition of abdominal breathing. This may contribute to the reduction of the hypercapnic ventilatory response during REM sleep.
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PMID:Respiratory changes associated with rapid eye movements in normo- and hypercapnia during sleep. 984 45

1. The disposition of 14C-methyl ethyl ketoxime (MEKO) was determined in the male F344 rat following oral, intravenous (i.v.) and dermal administration. 2. Oral doses of 2.7, 27 and 270 mg/kg were primarily excreted as CO2 (71-49%) in decreasing percentage as the dose increased. Excretion in urine (13-26%) and as volatiles (5-18%) increased as the dose increased. Five to 6% of the dose remained in the major tissues after 72 h. 3. An i.v. dose of 2.7 mg/kg was also principally excreted as CO2 (48.8%) with excretion in urine and as expired volatiles accounting for 21.4 and 11.4%, respectively. About 7% of the administered radioactivity remained in the tissues after 72 h. 4. Following dermal administration, 13 and 26% of a 2.7 and 270 mg/kg dose, respectively, were absorbed. Volatilization from the dose site prior to placement in the metabolism cage may account for the low absorption. 5. MEKO was biotransformed to at least five polar metabolites that could only be partially resolved by anion exchange chromatography. Incubation with glucuronidase, but not sulphatase, changed the urinary metabolic profile. Methyl ethyl ketone was a major component in the volatiles.
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PMID:Disposition of methyl ethyl ketoxime in the rat after oral, intravenous and dermal administration. 984 47

Large cage and field studies were conducted to compare the efficacy of 2 American Biophysics Corporation mosquito traps, the standard professional (PRO) trap and a new counterflow geometry (CFG) trap. The PRO trap utilizes conventional downdraft technology and the CFG trap uses a patent-pending technology. In large cage studies, similarly baited CFG traps captured approximately 1.7 times as many laboratory-reared Aedes taeniorhynchus as the PRO trap. The CFG trap baited with CO2 + octenol resulted in significantly reduced landing counts compared to all other treatments; mean landing count was reduced from 233.8 (12.99/min), when no trap was present, to 24.7 (1.37/min). In field studies against natural populations of woodland species, the CFG trap captured 7.8 times more mosquitoes than the PRO trap overall, and approximately 11 times more Anopheles crucians, Anopheles quadrimaculatus, and Culex erraticus.
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PMID:Comparison of two American biophysics mosquito traps: the professional and a new counterflow geometry trap. 1048 Jan 15

Chronic expiratory flow limitation and hyperinflation are the mechanical hallmarks of chronic obstructive pulmonary disease (COPD). Although carbon dioxide retention is dependent on the severity of airflow limitation, there is considerable variability in the relationships between arterial carbon dioxide tension (Pa,CO2) and forced expiratory volume in one second (FEV1) or total lung resistance (RL). In stable COPD patients with severe airflow obstruction, shallow breathing and inspiratory muscle weakness are the main factors associated with CO2 retention. In stable COPD patients, the diaphragm is less effective than in normal subjects and, with increasing airflow obstruction and hyperinflation, the contribution to the generation of ventilatory pressure of the ribcage inspiratory muscles increased. Abdominal muscles are recruited during expiration in severe COPD patients and the expiratory rise in gastric pressure is directly related to intrinsic positive end-expiratory (alveolar) pressure (PEEPi). During acute bronchoconstriction, COPD patients with severe airflow obstruction recruited the rib cage inspiratory muscles proportionally more than the diaphragm. The associated recruitment of abdominal muscles results in a reduction in abdominal volume at end-expiration and contributes to a significant extent to PEEPi. Dynamic hyperinflation can be overestimated during chronic and acute airway obstruction if abdominal muscle function is not evaluated.
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PMID:Physiological changes during severe airflow obstruction in chronic obstructive pulmonary disease. 1074 Nov 1

Laparoscopic transperitoneal fusion of the L5-S1 spinal interspace has become a common procedure. Retroperitoneal retraction and laparoscopic instrumentation without insufflation also allows visualization of the upper lumbar spaces, but this procedure is much more difficult to accomplish. We review and compare our results using each of these techniques for the treatment of mechanical instability and chronic back pain. A total of 35 selected patients underwent intervertebral fusion between February 1996 and August 1998. Their mean age was 48 years. There were 22 female and 13 male patients. Standard CO2 insufflation was used in 10 patients with L5-S1 fusions. Retractional gasless technique was used in nine patients with fusions at L5-S1, 16 patients at L4-L5, one patient at L3-L4, three patients at L2-3, and one patient at L1-L2. Thus, we performed a total of 40 lumbar fusions in 35 patients. In the 19 patients with the gasless technique, a balloon dissector and retractor facilitated the retroperitoneal exposure. Seven of these 19 patients were converted to open procedures, most commonly due to lacerations of the peritoneal lining that prohibited visualization. None of the L5-S1 patients with insufflation were converted to open. Mean operative time in the insufflated patients was 152 min vs. 181 min for the retractional technique. There were seven complications in the transperitoneal group: one fusion device migration, one postoperative UTI, one intracerebral hemorrhage, one severe postoperative pancreatitis, and three iliac vein lacerations. There were 16 complications in the retroperitoneal group: one deep vein thromboses, one serosal bowel injury, one small tear in the spleen, one cage migration, one postoperative pulmonary atelectasis, one postoperative hydrocele, four postoperative ileus, and six peritoneal tears. The mean postoperative stay was three days for both groups. There were no deaths. The L5-S1 interspace is best approached transperitoneally for anterior fusion. Although the retroperitoneal retractional technique is much more difficult and has a longer and steeper learning curve, it does allow laparoscopic anterior fusion of the upper lumbar spine.
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PMID:Comparison of insufflation vs. retractional technique for laparoscopic-assisted intervertebral fusion of the lumbar spine. 1074 54


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