首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
ObjectivesThe aim of this study was to investigate blood lead level and its relationship to essential elements (zinc, copper, iron, calcium and magnesium) in school-age children from Nanning, China.MethodsA total of 2457 children aged from 6 to 14 years were enrolled in Nanning, China. The levels of lead (Pb), zinc (Zn), copper (Cu), iron (Fe), calcium (Ca) and magnesium (Mg) were determined by an atomic absorption spectrometer.ResultsThe mean blood lead level (BLL) was 57.21 ± 35.00 μg/L. 188 (7.65%) asymptomatic children had toxic lead level higher than 100 μg/L. The school-age boys had similar lead level among different age groups, while the elder girls had less BLL. The blood Zn and Fe were found to be increased in the boys with elevated BLL, but similar trends were not observed in the girls. Positive correlations between Pb and Fe or Mg (r = 0.112, 0.062, respectively, p < 0.01) and a negative correlation between Pb and Ca (r = −0.047, p < 0.05) were further established in the studied children.ConclusionsLead exposure in school-age children was still prevalent in Nanning. The boys and girls differed in blood levels of lead and other metallic elements. Lead exposure may induce metabolic disorder of other metallic elements in body.  相似文献   

2.
《Phytomedicine》2014,21(11):1458-1465
Yokukansan, a traditional Japanese herbal medicine, has been used for the management of neurodegenerative disorders and for the treatment of neurosis, insomnia, and behavioral and psychological symptoms of dementia. Recently, several studies have shown that yokukansan has a neuroprotective effect. The aim of this study was to examine the neuroprotective effect of yokukansan on hippocampal neurons from embryonic mouse brain against the effects of corticosterone, which is considered to be a stress hormone and to be cytotoxic toward neurons. The cell survival rates were measured by the WST-8 assay and LDH assay. Twenty-four hours after treatment with corticosterone, cell numbers were significantly decreased compared with the control or treatment with vehicle in a dose-dependent manner. When cells were treated with 30 μM corticosterone, the decrease in the number of cells was significantly recovered by treatment with yokukansan (100–1000 μg/ml) in a dose-dependent manner. However, yokukansan did not suppress the decrease in cell numbers that was induced by treatment with 100 μM corticosterone. In the LDH assay, treatment with yokukansan at a high concentration (500–1000 μg/ml) suppressed the LDH concentration induced by treatment with both 30 μM and 100 μM corticosterone compared to treatment with corticosterone alone, respectively. These results suggest that yokukansan protects against the cytotoxic effect of a low concentration of corticosterone on hippocampal neurons.  相似文献   

3.
JNKs (c-Jun N-terminal kinases) have the potential to serve as a therapeutic target for various inflammatory, vascular, neurodegenerative, metabolic and oncological diseases. In particular, ATP-competitive JNK3 inhibitors act as neuroprotective agents. Here we introduce 1,2-diaryl-1H-benzimidazole derivatives as selective JNK3 inhibitors from among our in-house compounds and describe our elucidation of their SAR using 3D-QSAR models. A predictive CoMFA model (q2 = 0.795, r2 = 0.931) and a CoMSIA model (q2 = 0.700, r2 = 0.937) were used to describe the non-linearly combined affinity of each functional group in the inhibitors.  相似文献   

4.
《Aquatic Botany》2005,83(1):61-70
This study examined the consistency of the effect of wave exposure on the morphology of Ecklonia radiata, a small kelp, across a broad geographic range (>1100 km). Fifteen morphological characters were measured on individuals from sites of low (2.5 ± 0.8 S.E.) and high (12.2 ± 2.0 S.E.) wave exposure (Baardseth's index) within six locations in southwestern Australia. With the exception of lateral width (P = 0.0001), none of the morphological characters were consistently statistically different (P > 0.06) between high and low wave exposure and correlations with wave exposure were generally weak (r < 0.60). While 12 of the 15 characters were statistically different (P < 0.008) between sites of different exposure within at least one location, the direction of difference (significant or not) was opposite between some locations for all but one character (lateral width). ANOSIM was not able to separate thalli from high and low exposure when all locations were pooled (Clarke's R = 0.127), but within each location most sites showed better separation (0.126 < Clarke's R < 0.829). Despite the lack of statistical differences, trends suggested that E. radiata responds to exposure by having drag-reducing (small size, narrow laterals and blades, low spinosity) and strength-increasing (relatively large holdfast, thick stipe and thick blades and lamina) morphological traits, as observed for several other kelps in small-scale studies. We conclude that while wave exposure does have an effect on kelp morphology, the effect is not independent of other location-specific processes.  相似文献   

5.
Warneckea populations from “sand-forest” or “sand-thicket” habitats in Tembe Elephant Park, South Africa, and Licuati Forest Reserve in adjacent southern Mozambique were previously thought to be a small-leaved form of W. sousae, which typically includes larger-leaved plants ranging from central Mozambique northward to Tanzania. We examine this hypothesis using molecular and morphological evidence. Maximum-likelihood phylogenetic analysis of combined nrDNA ETS and ITS sequence data failed to resolve W. sousae and the Maputaland populations as an exclusively monophyletic group. Instead, the Kenyan endemic W. mouririifolia was strongly supported as the sister species of W. sousae, and the Maputaland plants were resolved in a separate, strongly supported clade together with populations of an as-yet undetermined Warneckea species from northern Mozambique. A hypothesis of exclusive monophyly for the plants from Tembe and Licuati had moderate support in separate ETS and ITS1 analyses (bootstrap proportions of 88% and 81%, respectively). Statistically significant differences in leaf dimensions and internode length were found between the Maputaland plants and typical W. sousae. We conclude that the populations from Tembe and Licuati represent a distinct species, which we describe as W. parvifolia. The species differs from W. sousae in having shorter internodes (mostly 5–25 mm not 10–60 mm long), smaller leaves (mostly 14–32 × 8–19 mm not 40–76 × 22–52 mm), shorter petioles (mostly 1–1.5 mm not 1.5–6 mm long), smaller flowers (hypanthium 1 × 1.5–1.75 mm not 1.5–2 × 2 mm; calyx lobes 0.5 mm not 0.75 mm long; staminal filaments 3–4 mm not 5 mm long; style 4–5 mm not 9 mm long), and globose fruit (not obovoid). An IUCN conservation status of Endangered (EN) B1a, b(ii, iii) is indicated for W. parvifolia, due to its limited distribution and projected declines in its habitat quality and area of occupancy.  相似文献   

6.
《Phytomedicine》2014,21(7):992-997
Aphanizomenon flos-aquae (AFA) is a fresh water unicellular blue-green alga that has been traditionally used for over 25 years for its health-enhancing properties. Recent studies have shown the ability of a proprietary AFA extract (Klamin®) to improve mood, counteract anxiety, and enhance attention and learning. Aim of this study was to test the monoamine oxidase (MAO) inhibition activity of the same AFA extract and of its constituents phycocyanin (AFA-PC) and mycosporine-like aminoacids (AFA-MAAs). All compounds showed a dose-dependent selective inhibition of MAO-B activity as compared to MAO-A. The IC50 values of the AFA extract (concentration 10 mg/ml), AFA-PC and AFA-MAAs were 6.4 μl/ml, 1.33 μM and 1.98 μM, respectively, evidencing a mixed-type of inhibition for the AFA extract (Ki 0.99 μl/ml), a non-competitive inhibition for AFA-PC (Ki 1.06 μM) and a competitive inhibition for AFA-MAAs (Ki 0.585 μM). These results are important to explain the neuromodulating properties of the AFA extract Klamin®, which is rich in phenylethylamine, a general neuromodulator, that would nevertheless rapidly destroyed by MAO-B enzymes without the inhibitory activity of the synergic active principles AFA-PC and AFA-MAAs. The present investigation thus proposes the extract as potentially relevant in clinical areas such as mood disorders and neurodegenerative diseases.  相似文献   

7.
The effect of thermal environments during embryonic development as a proximate source of variation in the fitness of offspring has been examined in a wide variety of taxa, and reptiles have been proved to be excellent mode systems for research in this field. Here, we describe a study revealing the effects of ambient temperature and thermoregulation on locomotor performance of newborn ovoviviparous lizards. A 2 (background temperatures set at 18 °C or 22 °C) × 2 (allowing thermoregulation for 14 h or 10 h daily) factorial design experiment was carried out to examine the effects of ambient temperature and thermoregulation on the locomotor performance of newborn Guide toad-headed lizards (Phrynocephalus putjatia; Agamidae). Gravid females were collected in May 2010 from a population in Guide, Qinghai, northwestern China, and were transported to our laboratory in Hangzhou. Ten to fifteen females were housed together in 1200 mm × 600 mm × 700 mm (length × width × height) communal cages, which were placed in AAPS (artificial atmospheric phenomena simulator) rooms, and contained a substrate of sand (~400 mm depth), with rocks and pieces of clay tiles provided as shelter and basking sites. One light bulb (200 W) was suspended above one end of the cage to create a thermal gradient ranging from room temperature to 60 °C for 14 h or 10 h daily, and overnight temperatures followed AAPS temperatures (18 °C or 22 °C). Food (mealworms and house crickets) dusted with multivitamins and minerals and water were provided daily. Cages were checked twice daily for neonates after the first female gave birth, and neonates were immediately collected and weighed after birth.Twenty neonates from single litters of each testament were measured at birth for locomotor performance. All running trials were conducted at a body temperature of 30 °C, which was achieved by placing the newborns in an incubator at 30 °C for 30 min prior to testing. Locomotor performance was assessed by chasing the neonates along a 2-m-long racetrack, which was placed in a room at constant 30 °C, with one side of the racetrack transparent, allowing videoing with a Panasonic NV-DS77 digital video camera. The tapes were later examined with a computer using MGI VideoWave III software for PC (MGI Software Co., Toronto, Canada) for sprint speed in the fastest 250-mm interval and the maximal length. Each individual was measured five times after birth, at 15-day intervals, until 60 days.We found that locomotor performance of neonates was affected by thermoregulating opportunity, but not by background temperature. Neonates produced by females thermoregulated for 14 h daily performed better (both sprint speed and the maximal length) in the racetrack than those produced by females thermoregulated for 10 h daily. However, the interaction between background temperature and thermoregulating opportunity was not a significant source of variation in locomotor performance. Moreover, sprint speed was positively correlated to the maximal length in newborn P. putjatia. In summary, locomotor performance is a highly fitness-related trait, and this study implies that viviparity allows female P. putjatia to provide optimal temperatures for embryo development through thermoregulation, thereby producing well-performed offspring.  相似文献   

8.
Oxytocin is involved in the control of different behaviors, from sexual behavior and food consumption to empathy, social and affective behaviors. An imbalance of central oxytocinergic neurotransmission has been also associated with different mental pathologies, from depression, anxiety and anorexia/bulimia to schizophrenia, autism and drug dependence. This study shows that oxytocin may also play a role in the control of locomotor activity. Accordingly, intraperitoneal oxytocin (0.5–2000 μg/kg) reduced locomotor activity of adult male rats. This effect was abolished by d(CH2)5Tyr(Me)2-Orn8-vasotocin, an oxytocin receptor antagonist, given into the lateral ventricles at the dose of 2 μg/rat, which was ineffective on locomotor activity. Oxytocin (50–200 ng/site) also reduced and d(CH2)5Tyr(Me)2-Orn8-vasotocin (2 μg/site) increased locomotor activity when injected bilaterally into the substantia nigra, a key area in the control of locomotor activity. Conversely, the destruction of nigral neurons bearing oxytocin receptors by the recently characterized neurotoxin oxytocin-saporin injected into the substantia nigra, increased basal locomotor activity. Since oxytocin-saporin injected into the substantia nigra caused a marked reduction of neurons immunoreactive for tyrosine hydroxylase (e.g., nigrostriatal dopaminergic neurons) and for vesicular glutamate transporters VGluT1, VGluT2 and VGluT3 (e.g., glutamatergic neurons), but not for glutamic acid decarboxylase (e.g., GABAergic neurons), together these findings suggest that oxytocin influences locomotor activity by acting on receptors localized presynaptically in nigral glutamatergic nerve terminals (which control the activity of nigral GABAergic efferent neurons projecting to brain stem nuclei controlling locomotor activity), rather than on receptors localized in the cell bodies/dendrites of nigrostriatal dopaminergic neurons.  相似文献   

9.
As the serotonin transporter (SERT) is involved in several neurodegenerative and psychiatric disorders; radiopharmaceuticals to image the SERT by PET would be valuable in studying these diseases. To this end we synthesized diphenyloxide derivatives and sulfide analogs, as new tracers, incorporating a fluorine or oxyalkyl fluorinated group on 4′ or 5′-position on phenyl ring B. Three of these exhibited good to high in vitro affinity (7 < Ki < 8 nM) and selectivity for the SERT over the other monoamine transporters.  相似文献   

10.
The objective of this study was to investigate the regulation of water balance and dry matter (DM) intake of male Ethiopian Somali goats. Twenty-eight goats were grouped into four treatments; goats watered every day (W1), every 2nd day (W2), every 3rd day (W3) and every 4th day (W4) for a total period of 72 days. Plasma sodium and potassium were analyzed by flame photometry, plasma osmolality by freezing point depression, plasma protein concentration by TS refractometry, and the plasma vasopressin concentration by radioimmunoassay. Goats were fed grass hay ad libitum and were given 200 g of concentrates daily. The calculated daily water intake (ml/kg BW0.75) of W1, W2, W3 and W4 was 128 ± 4, 86 ± 4, 88 ± 4 and 78 ± 4, respectively, (P < 0.001, W1 versus the other groups). Calculated total concentrates intake did not change, whereas Group W2 and W4 consumed less hay on days of water deprivation (W1 versus W2, P < 0.01; W1 versus W4, P < 0.001). Plasma sodium concentration of W1 was 143 ± 1 mmol/l. Intermittent watering increased plasma sodium concentration from 140 or 141 ± 1 mmol/l to 145 or 146 ± 1 mmol/l every 2nd day in group W2. In W3, it increased from 139 ± 1 to 146 ± 1 mmol/l and in W4 from 137 ± 1 to 149 ± 1 mmol/l (P < 0.001 for all) on days after watering compared to last day of water deprivation, respectively. Corresponding changes were observed in plasma osmolality. Total plasma protein concentration increased only in W3 from 65 ± 1 to 67 ± 1 mmol/l on day 3 (P < 0.01) and in W4 from 65 ± 1 to 67 and 68 ± 1 mmol/l on days 3 and 4, respectively (P < 0.05). The plasma vasopressin concentration of W1 was close to 0.80 ± 0.28 pmol/l on all days, but it increased on dehydration days in W2 (P < 0.05). In W3, the vasopressin concentration increased from 0.95 or 1.19 pmol/l the day after watering to 3.11 ± 0.28 pmol/l on day 3 (P < 0.01). In W4, it was 0.82 ± 0.31 pmol/l the day after watering and reached 6.06 ± 0.31 pmol/l on day 4 (P < 0.001). We conclude that male Ethiopian Somali goats can be watered once every 3rd days, and that longer interval is not recommended because it demands marked mobilization of water saving mechanisms and causes decreased DM intake.  相似文献   

11.
Kinesthetic illusions by visual stimulation (KiNVIS) enhances corticomotor excitability and activates motor association areas. The purpose of this study was to investigate the effect of KiNVIS induction on muscular output function after short-term immobilization. Thirty subjects were assigned to 3 groups: an immobilization group, with the left hand immobilized for 12 h (immobilization period); an illusion group, with the left hand immobilized and additionally subjected to KiNVIS of the immobilized part during the immobilization period; and a control group with no manipulation. The maximum voluntary contraction (MVC), fluctuation of force (force fluctuation) during a force modulation task, and twitch force were measured both before (pre-test) and after (post-test) the immobilization period. Data were analyzed by performing two-way (TIME × GROUP) repeated measures ANOVA. The MVC decreased in the immobilization group only (pre-test; 37.8 ± 6.1 N, post-test; 32.8 ± 6.9 N, p < 0.0005) after the immobilization period. The force fluctuation increased only in the immobilization group (pre-test; 2.19 ± 0.54%, post-test; 2.78 ± 0.87%, p = 0.007) after the immobilization period. These results demonstrate that induction of KiNVIS prevents negative effect on MVC and force fluctuation after 12 h of immobilization.  相似文献   

12.
In this study, seven 30-norlupane derivatives (28) was obtained from the chemical oxidation of betulinic acid followed by biotransformation via Bacillus megaterium CGMCC 1.1741. And metabolites 24 and 68 were newly identified products. In the first step, betulinic acid was chemically oxidized to platanic acid (1). Following the chemical oxidation, B. megaterium catalyzed the hydroxylation at C-7, C-11, C-15 and C-23 of platanic acid (1) as well as the oxidation of C-3 hydroxyl group. Compared to the labor-intensive isolation from natural plants, this chemical-microbial semi-synthesis is more capable to provide increased structural diversity of oxygenated 30-norlupane. Finally, the potential neuroprotective effect of the derivatives was assessed on neuron-like PC12 cells induced by cobalt chloride (CoCl2). Metabolite 6 showed a potent neuroprotective activity.  相似文献   

13.
A preliminary study was conducted to delineate the ameliorating effect of dietary zinc nanoparticles (Zn-NPs) against thermal stress in Pangasius hypophthalmus reared under concurrent exposure to lead (Pb) and elevated temperature (34 °C). Three diets were formulated such as control (no Zn-NPs), Zn-NPs 10 and 20 mg/kg diet. Two hundred and thirty four fish were randomly distributed in to six treatments groups in triplicates; such as control group (no Zn-NPs in diet and unexposed to Pb and temperature, Ctr/Ctr), control diet with concurrent exposure to Pb and temperature (Pb-T/Ctr), Zn-NPs 10 and 20 mg/kg without stressors (Zn-NPs 10 mg/kg, Zn-NPs 20 mg/kg), Zn-NPs 10 and 20 mg/kg diet with concurrent exposure to Pb and temperature (Pb-T/Zn-NPs 10 mg/kg, Pb-T/Zn-NPs 20 mg/kg). The Pb in treated water was maintained at the level of 1/21th of LC50 (4 ppm) at 34 °C temperature in stressors groups. Post 60 days feeding trial, critical thermal minimum (CTmin), lethal thermal minimum (LTmin), and critical thermal maximum (CTmax), lethal thermal maximum (LTmax) and biochemical attributes on P. hypophthalmus were evaluated. The results indicated that, dietary supplementation of Zn-NPs increased the CTmin, LTmin and CTmax, LTmax in P. hypophthalmus. Positive correlations were observed between CTmin LTmin (Y = − 0.495 + 10.08x, R2, 0.896) and CTmax LTmax (Y = − 0.872 + 4.43x, R2, 0.940). At the end of the thermal tolerance study, oxidative stress and lipid peroxidation (LPO) were significantly reduced and neurotransmitter enzyme was significantly increased in the groups fed with Zn-NPs @ 10 mg and 20 mg/kg diet. Overall results indicated that dietary Zn-NPs can confer protection against thermal stress in P. hypophthalmus.  相似文献   

14.
We report the effects of ATP and Mg2+ on the activity of intracellular chloride channels. Mitochondrial and lysosomal membrane vesicles isolated from rat hearts were incorporated into bilayer lipid membranes, and single chloride channel currents were measured. The observed chloride channels (n = 112) possessed a wide variation in single channel parameters and sensitivities to ATP. ATP (0.5–2 mmol/l) modulated and/or inhibited the chloride channel activities (n = 38/112) in a concentration-dependent manner. The inhibition effect was irreversible (n = 5/93) or reversible (n = 15/93). The non-hydrolysable ATP analogue AMP-PNP had a similar inhibition effect as ATP, indicating that phosphorylation did not play a role in the ATP inhibition effect. ATP modulated the gating properties of the channels (n = 6/93), decreased the channels' open dwell times and increased the gating transition rates. ATP (0.5–2 mmol/l) without the presence of Mg2+ decreased the chloride channel current (n = 12/14), whereas Mg2+ significantly reversed the effect (n = 4/4). We suggest that ATP-intracellular chloride channel interactions and Mg2+ modulation of these interactions may regulate different physiological and pathological processes.  相似文献   

15.
《Cytokine》2011,53(3):168-174
The present study examined the effects of aerobic training and energy restriction on adipokines levels in mesenteric (MEAT) and retroperitoneal (RPAT) white adipose tissue from obese rats. Male Wistar rats were fed with standard laboratory diet (Control group) or high fat diet (HFD). After 15 weeks, HFD rats were randomly assigned to the following groups: rats submitted to HFD, which were sedentary (sedentary HFD, n = 8) or trained (trained HFD, n = 8); or submitted to energy-restriction (ER), which were sedentary (sedentary ER, n = 8) or trained (trained ER, n = 8). Trained rats ran on a treadmill at 55% VO2max for 60 min/day, 5 days/week, for 10 weeks. ER rats were submitted to a reduction of 20% daily caloric ingestion compared to the Control group. ER and aerobic training decreased body weight, MEAT and RPAT absolute weight, and fat mass. IL-6, IL-10 and TNF-α levels were decreased and adiponectin did not change in RPAT in response to ER protocol. On the other hand, ER and the aerobic training protocol decreased IL-6, TNF-α and adiponectin levels in MEAT. Absolute MEAT weight showed a positive correlation with IL-6 (r = 0.464), TNF-α (r = 0.508); and adiponectin (r = 0.342). These results suggest a tissue-specific heterogeneous response in adipokines level. The combination of the protocols (aerobic training and energy restriction) did not induce an enhanced effect.  相似文献   

16.
Loss of hand function and finger dexterity are main disabilities in the upper limb after stroke. An electromyography (EMG)-driven hand robot had been developed for post-stroke rehabilitation training. The effectiveness of the hand robot assisted whole upper limb training was investigated on persons with chronic stroke (n = 10) in this work. All subjects attended a 20-session training (3–5 times/week) by using the hand robot to practice object grasp/release and arm transportation tasks. Significant motor improvements were observed in the Fugl-Meyer hand/wrist and shoulder/elbow scores (p < 0.05), and also in the Action Research Arm Test and Wolf Motor Function Test (p < 0.05). Significant reduction in spasticity of the fingers as was measured by the Modified Ashworth Score (p < 0.05). The training improved the muscle co-ordination between the antagonist muscle pair (flexor digitorum (FD) and extensor digitorum (ED)), associated with a significant reduction in the ED EMG level (p < 0.05) and a significant decrease of ED and FD co-contraction during the training (p < 0.05); the excessive muscle activities in the biceps brachii were also reduced significantly after the training (p < 0.05).  相似文献   

17.
Brain natriuretic peptide (NT-pro-BNP) is used as marker of cardiac and pulmonary diseases. However, the predictive value of circulating NT-pro-BNP for cardiac and pulmonary performance is unclear in physiological conditions. Standard echocardiography, tissue Doppler and forced spirometry at rest were used to assess cardiac parameters and forced vital capacity (FVC) in two groups of athletes (16 elite male wrestlers (W), 21 water polo player (WP)), as different stress adaptation models, and 20 sedentary subjects (C) matched for age. Cardiopulmonary test on treadmill (CPET), as acute stress model, was used to measure peak oxygen consumption (peak VO2), maximal heart rate (HRmax) and peak oxygen pulse (peak VO2/HR). NT-pro-BNP was measured by immunoassey sandwich technique 10 min before the test – at rest, at the beginning of the test, at maximal effort, at third minute of recovery. FVC was higher in athletes and the highest in W (WP 5.60 ± 0.29 l; W 6.57 ± 1.00 l; C 5.41 ± 0.29 l; p < 0.01). Peak VO2 and peak VO2/HR were higher in athletes and the highest in WP. HRmax was not different among groups. In all groups, NT-pro-BNP decreased from rest to the beginning phase, increased in maximal effort and stayed unchanged in recovery. NT-pro-BNP was higher in C than W in all phases; WP had similar values as W and C. On multiple regression analysis, in all three groups together, ΔNT-pro-BNP from rest to the beginning phase independently predicted both peak VO2 and peak VO2/HR (r = 0.38, 0.35; B = 37.40, 0.19; p = 0.007, 0.000, respectively). NT-pro-BNP at rest predicted HRmax (r = −0.32, B = −0.22, p = 0.02). Maximal NT-pro-BNP predicted FVC (r = −0.22, B = −0.07, p = 0.02). These results show noticeable predictive value of NT-pro-BNP for both cardiac and pulmonary performance in physiological conditions suggesting that NT-pro-BNP could be a common regulatory factor coordinating adaptation of heart and lungs to stress condition.  相似文献   

18.
Monosialoganglioside (GM1) is a glycosphingolipid present in most cell membranes that displays antioxidant and neuroprotective properties. It has been recently described that GM1 induces vasodilation. However, the mechanisms underlying GM1-induced vasodilation were not evaluated to date. Therefore, in this study we investigated whether the nonspecific NOS inhibitor l-NAME prevents GM1-induced vasodilation in rats. The systemic injection of GM1 (50 mg/kg, i.p.) increased the outer diameter of pial vessels by 50% in anesthetized animals at 30 min, and this effect was fully prevented by the administration of the nitric oxide synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME, 60 mg/kg, i.p. 15 min before GM1 injection).A 30 min exposure of cerebral cortex slices to GM1 (100 μM) increased the content of nitrite plus nitrate (NOx) by 50%. Addition of l-NAME (100 μM) to the incubation medium fully prevented GM1-induced NOx increase. Conversely, a 60 min exposure of slices to GM1 (100 μM) decreased NOx content, revealing a biphasic effect of GM1. Our results suggest that NO plays an important role in the vasodilation induced by GM1.  相似文献   

19.
Jumping on an elastic surface produces a number of sensory and motor adjustments. This effect caused by jumping on the trampoline has been called “trampoline aftereffect”. The objective of the present study was to investigate the neuromuscular response related with this effect. A group of 15 subjects took part in an experimental session, where simultaneous biomechanical and electromyographic (EMG) recordings were performed during the execution of maximal countermovement jumps (CMJs) before and after jumping on an elastic surface. We assessed motor performance (leg stiffness, jump height, peak force, vertical motion of center of mass and stored and returned energy) and EMG activation patterns of the leg muscles. The results showed a significant increase (p ? 0.05) of the RMS EMG of knee extensors during the eccentric phase of the jump performed immediately after the exposure phase to the elastic surface (CMJ1), and a significant increase (p ? 0.05) in the levels of co-activation of the muscles crossing the ankle joint during the concentric phase of the same jump. Results related with motor performance of CMJ1 showed a significant increase in the leg stiffness (p ? 0.01) due to a lower vertical motion of center of mass (CoM) (p ? 0.005), a significant decrease in jump height (p ? 0.01), and a significantly smaller stored and returned energy (p ? 0.01). The changes found during the execution of CMJ1 may result from a mismatch between sensory feedback and the efferent copy.  相似文献   

20.
IntroductionTrace elements may play an important role in bipolar disorders. The objective of this study is to determine serum copper and zinc, blood lead and cadmium and urine lead, cadmium and thallium concentrations in patients diagnosed with bipolar disorders and to compare these levels with those of a healthy control group.Materials and methodsA total of 25 patients diagnosed with bipolar disorder and 29 healthy subjects participated in this study. Serum copper and zinc concentrations were measured using flame atomic absorption spectrometry; the blood lead and cadmium concentrations were measured by electrothermal atomization atomic absorption spectrometry with Zeeman background correction; urine lead, cadmium and thallium concentrations were measured by inductively coupled plasma mass spectrometry.ResultsMedian blood and urine lead and cadmium levels were significantly higher among the bipolar patients than among the control group: Blood lead (μg/dL): patient median: 3.00 (IQR: 1.40–4.20); control median (μg/dL): 2.20 (IQR: 0.90–3.00) p = 0.040. Blood cadmium (μg/L): patient median: 0.39 (IQR: 0.10–1.15); control median: 0.10 (IQR: 0.10–0.17) p < 0.001. The median of cadmium (μg/L) in patients who smoked (1.20 IQR: 0.44–2.30) was higher than that in non-smokers (0.12 IQR: 0.10–0.34) p < 0.001. There was a statistically significant increase (p = 0.001) in zinc levels among patients in the manic phase (mean 111.28, SD: 33.36 μg/dL) with respect to the control group (mean 86.07, SD: 12.39 μg/dL).ConclusionsThe results suggest that there could be higher levels of some toxic trace elements in the group of patients with bipolar disorder than in the healthy control group.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号