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排序方式: 共有1297条查询结果,搜索用时 15 毫秒
1.
Previous epidemiologic studies have assessed the role of the exposure to ambient air pollution in the development of cardiac birth defects, but they have provided somewhat inconsistent results. To assess the associations between exposure to ambient air pollutants and the risk of cardiac defects, a population-based case-control study was conducted using 1087 cases of cardiac defects and a random sample of 10,870 controls from 1,533,748 Taiwanese newborns in 2001 to 2007.Logistic regression was performed to calculate odds ratios for 10 ppb increases in O3 and 10 μg/m3 increases in PM10. In addition, we compared the risk of cardiac defects in 4 categories-high exposure (>75th percentile); medium exposure (75th to 50th percentile); low exposure (<50th–25th percentile); reference (<25th percentile) based on the distribution of each pollutant. The risks of ventricular septal defects (VSD), atrial septal defects (ASD), and patent ductus arteriosus (PDA) were associated with 10 ppb increases in O3 exposure during the first 3 gestational months among term and preterm babies. In comparison between high PM10 exposure and reference category, there were statistically significant elevations in the effect estimates of ASD for all and terms births. In addition, there was a negative or weak association between SO2, NO2, CO, and cardiac defects.The study proved that exposure to outdoor air O3 and PM10 during the first trimester of gestation may increase the risk of VSD, ASD, and PDA. 相似文献
2.
Phosphatidylinositol (PI) signaling during organophosphate (OP) induced convulsions and tissue Ca2+ changes in 10 weeks old male, and 14 weeks old non-pregnant and pregnant female rats, and the offspring of the latter were explored. Brain inositol and inositol-1-phosphate (Ins1P) served as indices of alterations in brain PI signaling, and brain tissue Ca2+ as an index of early neuronal injury. A dose of malaoxon OP, which produced convulsions in about 60% of the exposed rats in different rat groups, was 39.2 for male, and 8.2 mg/kg for pregnant female rats, respectively. Malaoxon (8.2 mg/kg) did not produce convulsions in non-pregnant female rats. All the rats were followed for 1 or 4 hr subsequent to malaoxon. Malaoxon decreased cerebral inositol in both male and female rats, and the decrease was similar in spite of the dose difference. The decrease was larger in the convulsing than in the non-convulsing rats. A tendency towards a decrease of brain inositol also occurred in the offspring. Ins1P levels were markedly increased in male, and also in non-pregnant female rats, but not in the brains of pregnant female rats. Ins1P was not markedly changed in the brains of the offspring. Malaoxon elevated brain tissue Ca2+ in male but not in female rats or their offspring. Cholinergic systems and PI signaling in the brain seem to be associated with OP-induced convulsions both in male and female rats; females seem to be more sensitive than males. Malaoxon may also have slightly modified PI signaling in the offspring brain. Hormonal factors are likely to modify OP CNS toxicity and cholinergic stimulation of brain PI signaling. 相似文献
3.
Medical and Surgical Dermatology - 相似文献
4.
Jouni Sirvi Hannele Lahtinen Paavo Riekkinen Jr. Paavo J. Riekkinen 《Experimental neurology》1994,125(2)
The present experiment studied whether a dysfunction of the noradrenergic neurons is related to spatial learning impairment by investigating the levels of noradrenaline in the brain and periphery as well as the acquisition of water maze task in saline-pretreated young rats, in noradrenergic neurotoxin (DSP-4)-pretreated young rats and in saline-pretreated aged rats. Aged rats, which had an increased escape latency onto the hidden platform, revealed a decreased noradrenaline content in the heart, but not in the hippocampus, striatum, or hypothalamus, whereas DSP-4-pretreated rats had decreased noradrenaline content in the brain; the acquisition of water maze task was not impaired. These results suggest that the peripheral noradrenergic system can show age-related changes different from those in the central noradrenergic system, and they failed to provide support for the hypothesis that decreased activity of the central noradrenergic nerves is related to impairment in the acquisition of the water maze task. 相似文献
5.
Paavo Riekkinen Jr. Jouni Sirvi Pekka Jkl Maria Mazurkiewicz Antti Valjakka Minna Riekkinen Paavo Riekkinen 《Brain research bulletin》1991,27(2):287-289
Quisqualic acid NBM lesions had no effect on water maze performance, but slightly impaired passive avoidance acquisition. GammavinylGABA treatment alone had no effect on the passive avoidance and water maze performance, but aggravated acquisition deficit in rats subjected to NBM lesioning. However, gammavinylGABA-treated NBM-lesioned rats reached control level of performance. 相似文献
6.
Paavo Riekkinen Jr. Minna Riekkinen Antti Valjakka Paavo Riekkinen Jouni Sirvio
《Brain research》1992,570(1-2):293-299
The present study examines the effects of noradrenergic lesions (either DSP-4 i.p. or 6-hydroxydopamine (6-OHDA) into the dorsal noradrenergic bundle on biochemical (noradrenaline (NA), dopamine (DA), serotonin (5-HT) and choline acetyltransferase (ChAT) activity) and cortical EEG (quantitative EEG (qEEG) and high-voltage spindle (HVS) activity in young and aged rats. Near complete 6-OHDA NA lesions, but not partial DSP-4 NA lesions, increased HVS activity in young rats. DSP-4 and 6-OHDA lesions produced no significant changes in the 5-HT or DA levels or in the ChAT activity in young rats. In some of the aged rats, DSP-4 produced similar biochemical and HVS effects, as it induced in young rats. In the remainder of the aged rats, NA levels were greatly and 5-HT levels slightly decreased. DA levels and ChAT activity were unaltered in either set of aged rats. HVS activity was increased only in that group of aged rats with the greatly lowered NA content. These results suggest that: (1) some of the aged rats are more sensitive to DSP-4 treatment than young adult rats; and (2) NA depletions have to be complete to produce an increase in HVS activity in young and aged rats. 相似文献
7.
In experimental animals the jaw-opening reflex in response to stimulation of pulp nerves has been used as a nociceptive reflex. However, there seems to be only scanty information about the amount and types of pulp nerve fibres that mediate the reflex. In the present work on 8 anesthetized cats electrical thresholds of single functional pulp nerve units were compared to the thresholds of jaw-opening reflex. Monopolar cathodal current pulses were applied to each canine tooth. Reflex responses of the digastric muscle were recorded. The inferior alveolar nerve of the left side in 3 cats was exposed for nerve dissection and responses of pulp nerve units coming from the lower left canine tooth were recorded. The mean threshold of the jaw-opening reflex with 10 ms pulses was 5.9 +/- 3.0 (SD) microA. Below or at the level only part of the fast conducting pulp nerve units could be activated. Thresholds of A- (n = 32) and C- (n = 24) fibres were 9.9 +/- 5.7 and 37.4 +/- 14.5 (SD) microA respectively. Nerves of the periodontal tissues (20 units recorded) were not activated with current pulses of up to 200 microA applied to the tooth. Consequently, at threshold level the jaw-opening reflex in response to the present type of stimulation is mediated by the fast conducting intradental nerve units. 相似文献
8.
Marja -Leena Kortelainen Tuomo Lapinlampi Jorma Hirvonen 《European journal of applied physiology》1989,58(5):514-521
Summary Guinea-pigs were treated with chlorpromazine or 0.9% NaCl and exposed to +4° C or +23° C for 2 h. Hypothalamic noradrenaline
(NA), dopamine (DA), 5-hydroxytryptamine (5HT), 3-methoxy-4-hydroxyphenylethylene-glycol (MHPG), homovanillinic acid (HVA)
and 5-hydroxyindoleacetic acid (5-HIAA) were determined by high-performance liquid chromatography. Serum and urinary catecholamines,
muscle and liver glycogen and blood glucose were also measured. Chlorpromazine caused deep hypothermia at this moderately
cold temperature and slight hypothermia at room temperature. Cold increased the activity of noradrenergic and serotonergic
neurons, as indicated by the increase in hypothalamic MHPG and 5-HIAA and also the MHPG∶NA and 5-HIAA∶5-HT ratios. A tendency
towards drug-induced inhibition of hypothalamic serotonergic neurons was seen, although this was not significant. A drug-induced
inhibition of noradrenergic neurons could not be ruled out. Increased drug-induced turnover of DA was observed in the cold,
and a tendency in the same direction was seen at room temperature. Excretion of DA into the urine was induced by chlorpromazine.
The hypothermic guinea-pigs had low serum catecholamines, indicating diminished sympathetic activity, but high urinary catechols,
a sign of cold stress. 相似文献
9.
10.
Klemola R Huttunen P Laine M Weckström M Hirvonen J 《Acta physiologica Scandinavica》1999,165(3):293-297
In this study our aims were to investigate the presence and source of catecholamines in pericardial fluid of normotensive, reserpine-treated and spontaneously hypertensive rats. We found that noradrenaline is the only detectable catecholamine present in rat pericardial fluid. The effect of reserpine 6, 12, and 214 h after pre-treatment with 5 mg kg(-1) (8.2 micromol kg(-1)) i.p. shows that the concentration of noradrenaline in pericardial fluid reflects the amount of noradrenaline released within the heart rather than the amount of noradrenaline in plasma. Using spontaneously hypertensive rats (SHR) as a model for primary hypertension we could show that the level of pericardial noradrenaline is approximately threefold in the pericardial fluid of the SHRs when compared to respective values of age-matched normotensive Wistar-Kyoto rats (WKY), suggesting that there was an increased noradrenaline overflow in the hearts of the SHRs. In conclusion, determination of the noradrenaline concentration in the pericardial fluid might provide a new method for estimating the release of noradrenaline in the heart. 相似文献