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Winston N. Bloch Jr. MD Trent R. Lewis PhD Kenneth A. Busch MES John G. Orthoefer DVM Jerry F. Stara DVM 《Archives of environmental & occupational health》2013,68(5):342-353
Cardiovascular status of beagle dogs was assessed after five years’ exposure to temperature- and humidity-conditioned filtered air, or to one of the following air pollutant treatments: raw auto exhaust (RAE); irradiated auto exhaust (IAE); oxides of sulfur (SOX); RAE + SOX; “low” nitric oxide and “high” nitrogen dioxide; and “high” NO and “low” NO2. Incidence of both electrocardiographic and vectorcardiographic abnormalities suggested association between air pollution exposure and cardiac electrophysiologic dysfunction, which may or may not have pathologic basis, Incidences of pulmonary and systemic hypertension did not show association with air pollutant exposure. It is speculated that atherosclerosis was responsible for two myocardial infarctions observed, and that atherosclerotic process, if present, was potentiated by carbon monoxide, as has been reported in other animal species. 相似文献
74.
Lepomäki V Paavilainen T Matomäki J Hurme S Haataja L Lapinleimu H Liisa Lehtonen L Komu M Parkkola R;PIPARI Study Group 《Pediatric radiology》2012,42(6):692-698
Background
White matter maturation is characterised by increasing fractional anisotropy (FA) and decreasing mean diffusivity (MD). Contradictory results have been published on the effect of premature birth on white matter maturation at term-equivalent age.Objective
To assess the association of gestational age and low birth-weight-for-gestational-age (z-score) with white matter maturation.Materials and methods
Infants (n?=?76, 53 males) born at different gestational ages were imaged at term-equivalent age. Gestational age and birth weight z-score were used as continuous variables and the effect on diffusion parameters was assessed. Brain maturation was studied using regions-of-interest analysis in several white matter areas.Results
Gestational age showed no significant effect on white matter maturation at term-equivalent age. Children with low birth weight z-score had lower FA in the genu and splenium of the corpus callosum (regression, P?=?0.012 and P?=?0.032; correlation, P?=?0.009 and P?=?0.006, respectively), and higher MD in the splenium of the corpus callosum (regression, P?=?0.002; correlation, P?=?0.0004) compared to children whose birth weight was appropriate for gestational age.Conclusion
Children with low birth weight relative to gestational age show delay and/or anomaly in white matter maturation at term-equivalent age. 相似文献75.
Maternally acquired immunity in newborns from women infected by the human immunodeficiency virus 总被引:2,自引:0,他引:2
MI de Moraes-Pinto CK Farhat SB Carbonare SP Curti MES Otsubo DS Lazarotti RC Campagnoli MMS Carneiro-Sampaio 《Acta paediatrica (Oslo, Norway : 1992)》1993,82(S385):1034-1038
Maternally acquired immunity was studied in 16 pairs of human immunodeficiency virus (H1V)-seropositive women and their newborns, and was compared to 18 control mother-newborn pairs. The HIV-infected women had higher IgG levels than the control subjects, but no difference was observed between newborn samples, presumably due to the limited placental IgC transfer in the HIV group. A poor type 2 poliovirus antibody transfer was also noted in this group. The population of newborns lacking demonstrable measles antibodies was higher in the HIV group than in the control group, probably because many of the HIV-infected mothers lacked measles antibodies also. These results show that maternally acquired immunity may be affected to newborns from HIV-infected women, either because of low maternal serum antibody levels or deficient transplacental transfer. If so, the measles vaccine schedule should be revised for these children and the same should be done for future passive immunization regarding fetus protection in pregnant HIV-seropositive women. 相似文献
76.
Kajander S Kallio T Alanen A Komu M Forsström J 《Acta radiologica (Stockholm, Sweden : 1987)》2000,41(4):357-360
Purpose: To 1) assess the potential of magnetization transfer (MT)-weighted MR imaging to improve the often poor visibility of native kidneys in patients with a renal transplant; and 2) compare low-field MR imaging and ultrasonography (US) for imaging these fibrotic kidney remnants.Material and Methods: Seventy-two native kidneys of 36 patients were prospectively evaluated with US and MR. In low-field (0.1 T) MR imaging, T1-, T2- and MT-weighted sequences were used. MT-weighted images were compared with T2-weighted images in their ability to delineate the kidneys from their surroundings whereas US and MR were compared for detection of renal cysts and possible solid tumors.Results: MT-weighted images proved superior to conventional T2-weighted images in producing contrast between the kidney remnants and their fatty surroundings. Although US revealed a few small renal cysts that were not seen at MR images, no statistical difference was found between the two modalities in this respect.Conclusion: MT imaging, due to its unique protein-specific signal depression, offers significantly improved visualization and delineation of end-stage kidneys. US, because its better availability and cost-benefit ratio, remains the method-of-choice compared to low-field MR imaging in detecting cysts in multicystic kidneys. MR investigation is helpful in selected patients and may be used as an alternative. 相似文献
77.
Parkkola RK Rytökoski UM Komu MES Thomsen C 《Acta radiologica (Stockholm, Sweden : 1987)》2000,41(6):578-583
Purpose: To measure the cerebrospinal fluid (CSF) velocity in the cervical spinal canal both above and below a stenotic segment in patients with cervical spinal stenosis. The cord velocity was also measured at the level of C2.Material and Methods: Thirteen patients with chronic neck pain were examined with MR imaging. The degree of cervical spinal stenosis was assessed and measured on MR images and CSF velocity in the cervical spinal canal was measured using the phase MR flow quantification method at the level of C2 and below the stenotic segment. The cord motion was measured at the level of C2.Results: The peak velocities of CSF in front of the cord at the level of C2 were, on average, a little higher than behind the cord, but the interindividual variation was high. The caudal or rostral velocities of CSF above and below the stenotic segment could be measured in most cases and they were not dependent on the degree of stenosis when assessed visually. When the stenosis was assessed by relating the cord area to the dural sac area, a statistical correlation between narrow spinal canal and high velocities in the anterior CSF space below the stenotic segment was found.Conclusion: Spinal stenosis does not alter the cord or CSF velocities at the C2 level, but increases the velocity of CSF in the anterior CSF space below the stenotic segment when the stenosis is assessed by cord and dural sac area measurements. 相似文献
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79.
Quantitative HMRS and MRI volumetry indicate neuronal damage in the hippocampus of children with focal epilepsy and infrequent seizures 总被引:2,自引:0,他引:2
PURPOSE: Seizures induce progressive morphologic and functional changes in particular in the hippocampus, but whether and at what stage the hippocampus is affected in children with focal, temporal, nonintractable epilepsy is poorly known. We have now studied eventual metabolic and volume changes in the hippocampus of children with nonsymptomatic focal epilepsy taking antiepileptic medication (AEDs) but still having infrequent seizures. METHODS: Quantitative proton magnetic resonance spectroscopy ((1)HMRS) and volumetric MRI were used to study the hippocampal region of 11 pediatric outpatients (age 10 to 17 years) with cryptogenic localization-related epilepsy, and eight healthy volunteers (age 9 to 16 years) served as controls. The spectra were obtained bilaterally from the hippocampi by using the 1.5-T MR imager. The spectral resonance lines of N-acetyl group (NA), creatine and phosphocreatine group (Cr), choline-containing compounds (Cho), and myoinositol (mI) were analyzed quantitatively. The volume of the hippocampus was semiautomatically calculated. RESULTS: The mean concentration of NA was significantly decreased both in the focus side (9.02 +/- 2.00 mM) and in the nonfocus side (8.88 +/- 2.09 mM) of the patients compared with the controls (10.76 +/- 1.86 mM), in particular if the children had a history of generalized tonic-clonic seizures. The mean concentrations of Cho, Cr, and mI did not differ significantly between the patients and controls. Moreover, the mean hippocampal volume of the focus side of patients was significantly reduced compared with that of the controls. CONCLUSIONS: Metabolic changes in hippocampi were detected in children with nonsymptomatic localization-related epilepsy and infrequent seizures. Reduced NA could reflect neuronal metabolic dysfunction and/or neuronal damage, as indicated by our volumetric findings. 相似文献
80.
We have analyzed the normal patellar motion during the first 30 degrees of knee flexion by magnetic resonance imaging (MRI). Ten males and 10 females without knee symptoms were examined. The patellar articulation was imaged both sagittaly and axially with the knee flexed 0, 10, 20, and 30 degrees. The axial images were produced through the middle of the patellar articular cartilage. When the knee was in extension compared to 30 degrees flexion, the sulcus angle was greater, the lateral patellofemoral angle was smaller, there was more lateral patellar displacement, the patella tilted more laterally, and the congruence angle was directed more laterally. Differences between males and females were found. 相似文献