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Hr Intervals (hr + interval)
Selected AbstractsMethodological issues related to exhaled nitric oxide measurement in children aged four to six yearsPEDIATRIC PULMONOLOGY, Issue 2 2005Edward Napier MBBS Abstract This study was designed to test five methodological issues related to measurement of fractional exhaled nitric oxide (FENO) in children aged 4,6 years using commercially available apparatus. Participants attended two randomly selected schools. A respiratory questionnaire was completed. Measurements of FENO were made on successive days, using a NIOX® analyzer employing standard or modified methodologies. Ninety-one children participated in the study (mean age, 5.3 years; 46 boys). Using a standard methodology (n,=,61), FENO was successfully measured in 28 (46%) children, 1/12 aged 4 years, 12/25 aged 5 years, and 15/24 aged 6 years (trend test P,=,0.01). On the first assessment, FENO could be determined in more boys than girls (64% vs. 30%, respectively, P,=,0.008), but this gender difference was not apparent on the second assessment. Exhaled NO was reproducible over a 24-hr period; the mean difference between repeated measurements of natural log (ln) FENO was 0.016 parts per billion (ppb) (95% confidence limits, ,0.479, 0.511), n,=,20. Data from 35 assessments showed that values of FENO did not alter over nine individual, successive measurements. Use of a modified methodology in 30 children increased success in obtaining FENO, but these values were unreliable. In conclusion, measurements of FENO can be obtained in the majority of 5- and 6-year-old but not 4-year-old children. Exhaled NO measurements were reproducible over a 24-hr interval, and did not change over up to nine expiratory maneuvers in these young children. Pediatr Pulmonol. 2005; 40:97,104. © 2005 Wiley-Liss, Inc. [source] Dose- and time-dependent responses for micronucleus induction by X-rays and fast neutrons in gill cells of medaka (Oryzias latipes)ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2 2004Akinori Takai Abstract Medaka fish (Oryzias latipes) were exposed to various doses of X-rays or fast neutrons, and the frequency of micronucleated cells (MNCs) was measured in gills sampled at 12- or 24-hr intervals from 12 to 96 hr after exposure. The resulting time course of MNC frequency was biphasic, with a clear peak 24 hr after exposure, irrespective of the kind of radiation applied and the dose used. The half-life of MNCs induced in the gill tissues by the two exposures fluctuated around 28 hr, with no significant dose-dependent trend for either X-ray- or neutron-exposed fish. As assayed 24 hr after exposure, the MNC frequency increased linearly over the control level with increasing doses of both X-rays and fast neutrons. The relative biological effectiveness (RBE) of fast neutrons to X-rays for MNC induction was estimated to be 4.3 ± 0.6. This value is close to the RBE value of 5.1 ± 0.3 reported for fast neutron induction of somatic crossing-over mutations in Drosophila melanogaster that arise from recombination repair of DNA double-strand breaks. These results and other data support our conclusion that the medaka gill cell micronucleus assay is a reliable short-term test for detecting potential inducers of DNA double-strand breaks. Environ. Mol. Mutagen. 44:108,112, 2004. © 2004 Wiley-Liss, Inc. [source] Heritability of the Blood Pressure Response to Acute Ethanol Exposure in Five Inbred Strains of MiceALCOHOLISM, Issue 10 2000Daniel C. Hatton Background: Chronic alcohol consumption is a major risk factor for hypertension. There is evidence in humans that the susceptibility to alcohol-related hypertension may vary based on genotype. As a first step in investigating the genetic basis for alcohol-related hypertension, the current study was designed to assess the heritability of the blood pressure response to acute ethanol exposure by using AKR/J (AK), C57BL/6J (B6), DBA/2J (D2), Balb/cJ (Balb), and A/J (A) mice. Methods: Mean arterial pressure (MAP) was recorded continuously for 24 hr in freely moving mice from an indwelling femoral catheter before we tested the effects of saline or ethanol (2 g/kg ip) on blood pressure. Results: Relative to saline, ethanol caused a pressor response that peaked within 10 min, followed by a decline in MAP. Strain A mice had a significantly greater pressor response to ethanol than other strains and did not show a decline in MAP below baseline. All other strains showed a progressive fall in blood pressure below baseline across the 60 min measurement interval. Heritability was estimated to be 0.62 for the pressor response and 0.64 for the maximal depressor response. Repeated doses of ethanol at 1 hr intervals in A and B6 mice (0,2,1.5,1.5,1.5 g/kg ip) resulted in a dose-dependent increase in MAP in A mice for the first three doses and a dose-dependent decrease in MAP in B6 mice that was independent of blood ethanol concentrations. Conclusion: The results indicate that there is a significant genetic component to the acute blood pressure response to ethanol. [source] Binge Pattern Ethanol Exposure in Adolescent and Adult Rats: Differential Impact on Subsequent Responsiveness to EthanolALCOHOLISM, Issue 8 2000Aaron M. White Background: Recent evidence indicates that adolescent animals are more sensitive than adults to the disruptive effects of acute ethanol exposure on spatial learning. It is not yet known whether adolescent animals are also more sensitive than adults to the enduring neurobehavioral effects of repeated ethanol exposure. In this study, animals were exposed to ethanol in a binge-pattern during either adolescence or adulthood. At a time when all subjects were adults, spatial working memory was examined in the absence and presence of an acute ethanol challenge. Methods: Rats were exposed to ethanol (5.0 g/kg intraperitoneally) or isovolumetric saline at 48 hr intervals over 20 days. Exposure began on either postnatal day 30 (adolescent group) or 70 (adult group). Twenty days after the final injection, a time at which all animals were adults, the subjects were tested on an elevated plus maze and then were trained to perform a spatial working memory task on an eight-arm radial maze. At the beginning of each session of training on the working memory task, subjects retrieved food rewards on four of the eight arms. After a delay, subjects were placed on the maze and allowed to retrieve food from the remaining four arms. Results: Prior exposure to ethanol did not influence behavior on the plus maze. Performance of the groups did not differ during acquisition of the spatial working memory task with a 5 min delay or during subsequent testing with a 1 hr delay. However, animals treated with ethanol during adolescence exhibited larger working memory impairments during an ethanol challenge (1.5 g/kg intraperitoneally) than subjects in the other three groups. Conclusions: The findings indicate that binge pattern exposure to ethanol during adolescence enhances responsiveness to the memory-impairing effects of ethanol in adulthood. [source] Litter Characteristics of Gilts Artificially Inseminated with Transforming Growth Factor-,AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 3 2006Michelle Rhodes Problem, Semen is a rich source of transforming growth factor- , (TGF- ,) and it has been proposed that this molecule promotes embryonic survival by modifying immune responses to promote tolerance toward paternal antigens and by inducing release of cytokines that promote embryonic development. The role of TGF- , was tested using pigs by evaluating whether its addition to washed sperm improves conceptus survival and fetal growth. Methods of study, At estrus, gilts were artificially inseminated twice at 12-hr intervals with 100 mL of either washed semen resuspended in a commercial semen extender supplemented with 2 mg/mL of gelatin or washed semen in the same extender containing 65 ng/mL of TGF- ,1. Three boars were used as semen donors. At day 80 (±4 days) of gestation, gilts were sacrificed and reproductive tracts harvested. Results, Treatment had no effect (P > 0.10) on total or live fetuses per litter, implantation rate, fetal survival or percentage of corpora lutea resulting in live fetuses at day 80. Insemination with TGF- ,1 also did not affect total or average fetal weight or total placental weight. There was a tendency (P = 0.09) for average placental weight of live fetuses to be lower for pregnancies established in gilts treated with TGF- ,1. Also, placental efficiency (mass of fetus/mass of placenta) was greater (P < 0.05) for pregnancies established in gilts treated with TGF- ,1. The high fertility in control gilts (80% implantation rate and 11.5 live fetuses per litter) is indicative that soluble seminal factors are not necessary for the establishment of pregnancy. Conclusions, Within the ranges tested, concentration of TGF- , in the fluid phase of the inseminate is not an important determinant of conceptus survival or fetal and placental growth to day 80 of gestation in the pig. [source] | ||||||||||