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ABSTRACT: Preventing or reducing tau hyperphosphorylation is considered to be a therapeutic strategy in the treatment of Alzheimer's disease (AD). Rapamycin may be a potential therapeutic agent for AD, because the rapamycin-induced autophagy may enhance the clearance of the hyperphosphorylated tau. However, recent rodent studies show that the protective effect of rapamycin may not be limited in the autophagic clearance of the hyperphosphorylated tau. Because some tau-related kinases are targets of the mammalian target of rapamycin (mTOR), we assume that rapamycin may regulate tau phosphorylation by regulating these kinases. Our results showed that in human neuroblastoma SH-SY5Y cells, treatment with rapamycin induced phosphorylation of the type IIα regulatory (RIIα) subunit of cAMP-dependent kinase (PKA). Rapamycin also induced nuclear translocation of the catalytic subunits (Cat) of PKA and decreases in tau phosphorylation at Ser214 (pS214). The above effects of rapamycin were prevented by pretreatment with the mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitor U0126. In addition, these effects of rapamycin might not depend on the level of tau expression, because similar results were obtained in both the non-tau-expressing wild type human embryonic kidney 293 (HEK293) cells and HEK293 cells stably transfected with the longest isoform of recombinant human tau (tau441; HEK293/tau441). These findings suggest that rapamycin decreases pS214 via regulation of PKA. Because tau phosphorylation at Ser214 may prime tau for further phosphorylation by other kinases, our findings provide a novel possible mechanism by which rapamycin reduces or prevents tau hyperphosphorylation.
Neurochemistry International 01/2013; · 2.86 Impact Factor
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ABSTRACT: ObjectiveTo compare the phase radians in several cerebral regions between patients with Parkinson’s disease (PD) and control subjects,
and to evaluate whether iron deposition quantified by susceptibility-weighted imaging (SWI) is related to the severity of
motor symptoms of PD.
MethodsSWI consisted of both magnitude and phase images from a fully flow-compensated, 3-dimensional and gradient-echo (GRE) sequence.
Magnitude and phase data were collected at GE HD 1.5T. The regions evaluated included frontal white matter, grey matter, cerebrospinal
fluid, putamen, caudate nucleus (CN), substantia nigra pars compacta (SNc), substantia nigra pars reticulata (SNr), and red
nucleus (RN). A total number of 42 patients (12 patients without cognitive dysfunction, and 30 with cognitive dysfunction
from mild to moderate degrees) and 30 control subjects were employed in the present study.
ResultsThe phase radians of SNc, CN and RN in PD patients were lower than those in control subjects (P<0.05).
ConclusionThe phase radians can be used to estimate the brain iron deposition in PD patients, which may be helpful in the diagnosis
and longitudinal monitoring of PD.
目的比较帕金森氏病(Parkinson’s disease, PD)患者和健康对照者多个脑结构的相位偏移值(phase radians), 探讨相位偏移值的临床应用价值。
方法42 名PD患者及30 名年龄匹配的健康对照者均在1.5 T MR系统中进行头部检查。 所有PD 患者均存在轻度到中度认知功能缺损。 采用磁敏感成像获得相位图, 测量双侧尾状核、 壳核、 黑质致密带、 黑质网状带、 红核、 脑脊液、 额叶白质及额叶灰质内所感兴趣区的相位偏移值。
结果与正常对照组相比, PD组黑质致密带的相位偏移值均数显著缩短(P < 0.05)。 此外, PD组双侧尾状核和红核的相位偏移值亦显著降低(P < 0.05), 而黑质网状带的相位偏移值与对照组相比无统计学差异(P > 0.05)。
结论通过对相位偏移值的测定可以估测PD 患者脑内的铁沉积, 为PD 的活体诊断及病情监测提供帮助。
Neuroscience Bulletin 04/2012; 25(6):353-360. · 1.31 Impact Factor
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ABSTRACT: Phosphorylation of the cAMP response element binding protein (CREB) by cAMP-dependent kinase (PKA) is critical to memory formation. However, activation of PKA can also increase tau phosphorylation, which may contribute to memory impairment. Therefore, the regulation of PKA may be part of the mechanism by which glucocorticoids (GCs) influence memory. Additionally, the cellular response to GCs may be affected by the presence of human tau. The goal of this paper was to study GCs-mediated regulation of PKA as well as CREB and tau phosphorylation in wild-type HEK293 cells and HEK293 cells stably expressing human tau441 (HEK293/tau441 cells). By using dexamethasone (DEX) as GCs, we found that DEX induced a tau-dependent selective decrease in the level of PKA RIIβ subunit protein. The observed decrease in RIIβ expression was not due to alterations of mRNA levels and was reversed by inhibiting the proteasome with lactacystin. Moreover, the decrease in RIIβ did not diminish the co-localization of the catalytic subunit of PKA with tau and might contribute to the DEX-induced increase in tau phosphorylation at Ser-214. DEX also induced a tau-dependent decrease in CREB phosphorylation that could not be reversed by activating PKA with forskolin. Taken together, these results show that human tau protein may alter the GCs-mediated regulation of PKA activity and CREB phosphorylation.
Neurochemical Research 02/2012; 37(5):935-47. · 2.24 Impact Factor
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ABSTRACT: Evidence has suggested that insulin resistance (IR) or high levels of glucocorticoids (GCs) may be linked with the pathogenesis and/or progression of Alzheimer's disease (AD). Although studies have shown that a high level of GCs results in IR, little is known about the molecular details that link GCs and IR in the context of AD. Abnormal phosphorylation of tau and activation of μ-calpain are two key events in the pathology of AD. Importantly, these two events are also related with GCs and IR. We therefore speculate that tau phosphorylation and μ-calpain activation may mediate the GCs-induced IR. Akt phosphorylation at Ser-473 (pAkt) is commonly used as a marker for assessing IR. We employed two cell lines, wild-type HEK293 cells and HEK293 cells stably expressing the longest human tau isoform (tau-441; HEK293/tau441 cells). We examined whether DEX, a synthetic GCs, induces tau phosphorylation and μ-calpain activation. If so, we examined whether the DEX-induced tau phosphorylation and μ-calpain activation mediate the DEX-induced inhibition on the insulin-stimulated Akt phosphorylation. The results showed that DEX increased tau phosphorylation and induced tau-mediated μ-calpain activation. Furthermore, pre-treatment with LiCl prevented the effects of DEX on tau phosphorylation and μ-calpain activation. Finally, both LiCl pre-treatment and calpain inhibition prevented the DEX-induced inhibition on the insulin-stimulated Akt phosphorylation. In conclusion, our study suggests that the tau phosphorylation and μ-calpain activation mediate the DEX-induced inhibition on the insulin-stimulated Akt phosphorylation.
PLoS ONE 01/2012; 7(4):e35783. · 4.09 Impact Factor
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ABSTRACT: Aspirin (ASA) is one of the most widely used nonsteroidal anti-inflammatory drugs. ASA has primarily been used to treat headaches, rheumatic pain, and inflammation, but its therapeutic effects have recently been demonstrated on a range of disorders, including those of the central nervous system. In this study, we investigated whether ASA is neuroprotective in inflammation-mediated neurodegenerative diseases. Pretreatment with ASA reduced the lipopolysaccharide (LPS)-induced degeneration of dopaminergic (DA) neurons in mesencephalic neuron-glia cultures in a dose-dependent manner. The neuroprotective effect of ASA was attributed to the inhibition of microglial activation because of its observed inhibitory effects on LPS-stimulated nitric oxide, tumor necrosis factor-α, and superoxide production by microglial cells. Moreover, ASA increased the production of the anti-inflammatory cytokines transforming growth factor beta-1 and interleukin-10 in neuron-glia cultures after stimulation with LPS. Mechanistic studies revealed that the neuroprotective effects of ASA were mediated through the inhibition of nicotinamide adenine dinucleotide phosphate oxidase (PHOX), a key enzyme for superoxide production in microglia. These results suggest that ASA protects DA neurodegeneration by inhibiting the microglial-mediated oxidative stress/inflammatory response and by regulating the production of anti-inflammatory cytokines.
Journal of Molecular Neuroscience 05/2011; 46(1):153-61. · 2.50 Impact Factor
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ABSTRACT: Intestinal electrical stimulation (IES) has been shown to delay gastric emptying and reduce nutrient absorption in humans. The aim of this study was to investigate the effect of IES using an intraluminal method on postprandial blood glucose.
An oral glucose tolerance test with 150 g of glucose was performed in 10 healthy volunteers with and without IES (13 pulses/min, 300 ms and 5 mA). An intraluminal catheter with a pair of ring electrodes was incubated into the duodenum under endoscopy and used for IES. Gastric emptying was performed simultaneously using an established ultrasonic technique.
(1) IES significantly decreased the postprandial glucose level from 15 min to 90 min after the glucose load. (2) The serum insulin level at 30 min but not other times after the meal was lower in the IES session than that in the control session (p = 0.06). (3) The half-time of gastric emptying with IES was increased from 27 ± 4.8 min in the control session to 36 ± 8.5 min with IES (p < 0.01). (4) The symptoms score of dyspepsia were almost the same between the two sessions except that IES induced a slightly higher nausea symptom score.
IES decreases postprandial blood glucose possibly by delaying gastric emptying and other unknown mechanisms and the intraluminal method of IES may serve as an excellent screening and research tool for various applications of IES. Further clinical studies are needed to explore therapeutic potentials of IES for diabetes.
Obesity Surgery 02/2011; 21(2):224-30. · 3.29 Impact Factor
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Nian Xiong,
Jing Xiong,
Ghanshyam Khare,
Chunnuan Chen,
Jinsha Huang,
Ying Zhao,
Zhentao Zhang, Xian Qiao,
Yuan Feng,
Harrish Reesaul,
Yongxue Zhang,
Shenggang Sun,
Zhicheng Lin,
Tao Wang
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ABSTRACT: 3-methyl-1-phenyl-2-pyrazolin-5-one (edaravone), an effective free radical scavenger, provides neuroprotection in stroke models and patients. In this study, we investigated its neuroprotective effects in a chronic rotenone rat model for Parkinson's disease. Here we showed that a five-week treatment with edaravone abolished rotenone's activity to induce catalepsy, damage mitochondria and degenerate dopamine neurons in the midbrain of rotenone-treated rats. This abolishment was attributable at least partly to edaravone's inhibition of rotenone-induced reactive oxygen species production or apoptotic promoter Bax expression and its up-regulation of the vesicular monoamine transporter 2 (VMAT2) expression. Collectively, edaravone may provide novel clinical therapeutics for PD.
PLoS ONE 01/2011; 6(6):e20677. · 4.09 Impact Factor
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ABSTRACT: The study was aimed to examine the prevalence of depression in patients with Parkinson's disease (PD) and identify its features. A total of 131 out-patients, diagnosed as having idiopathic PD in accordance with the United Kingdom Parkinson's Disease Society Brain Bank criteria, were interviewed with questionnaire and evaluated by Mini-Mental State Examination (MMSE), Unified Parkinson's Disease Rating Scale (UPDRS), Hohen &Yahr staging (H&Y staging) and Hamilton Rating Scale for Depression (HRSD). Patients were divided into three groups in terms of HRSD score: depression group, sub-threshold depression group and non-depression group. The clinical variables and symptom profiles were obtained and compared among the three groups. The results showed that 27 patients (20.6%) fell into the depression group, 71 (54.2%) into the sub-threshold depression group, and 33 (25.2%) into the non-depression group. There were no differences in age, gender or tremor score among the groups (P>0.05). Significant differences were found in duration of PD, UPDRS score, rigidity score and H&Y stage between the sub-threshold depression group (or the depression group) and the non-depression group (P<0.05). Moreover, the clinical variables in the subthreshold depression group had the trend of increasing with the severity of PD and their values were similar to those in the depression group. Anhedonia, feeling of incapability, sleep disturbance, gastrointestinal symptoms and depressive moods were most common in the depression group. And these symptoms also were more common in the other two groups. It is concluded that depression and sub-threshold depression are common in PD and share similar clinical features. Furthermore, subthreshold depression might be the prodrome of depression and may develop into depression as the condition progresses.
Journal of Huazhong University of Science and Technology 12/2009; 29(6):725-8. · 0.38 Impact Factor
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ABSTRACT: This study investigated whether the curative effect of short-pulse gastric electrical stimulation (GES) on the vasopressin-induced dyspeptic symptoms was mediated by central opioid peptide-producing neurons. Five female beagle dogs implanted with 1 pair of electrodes in gastric serosa were used in a two-experiment study. In experiment one, the brain was scanned by positron emission tomography in 3 dogs with and without short-pulse GES, and the radioactivity in nuclei of solitary tract (NST) and hypothalamus was detected. Experiment two was composed of 4 sessions. In session one, the dogs were injected with vasopressin in the absence of short-pulse GES. With session two, the short-pulse GES was simultaneously given via the electrodes with the injection of vasopressin. In sessions three and four, naloxone and naloxone methiodide was administered respectively in the presence of short-pulse GES. Motion sickness-like symptoms were scored and compared among the different sessions. The results showed that the short-pulse GES significantly increased the radioactivity in NST and hypothalamic nuclei (P<0.05, vs control). The short-pulse GES could ameliorate the vasopressin-induced motion sickness-like symptoms in dogs. Naloxone, but not naloxone methiodide could attenuate the curative effects of short-pulse GES. It is concluded that NST and hypothalamic nuclei may participate in the mediation of the curative effects of short-pulse GES on dyspepsia-like symptoms. Central opioid peptide-containing neurons presumably mediate the therapeutic effect on dyspeptic symptoms of short-pulse GES.
Journal of Huazhong University of Science and Technology 12/2009; 29(6):701-4. · 0.38 Impact Factor
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ABSTRACT: To compare the phase radians in several cerebral regions between patients with Parkinson's disease (PD) and control subjects, and to evaluate whether iron deposition quantified by susceptibility-weighted imaging (SWI) is related to the severity of motor symptoms of PD.
SWI consisted of both magnitude and phase images from a fully flow-compensated, 3-dimensional and gradient-echo (GRE) sequence. Magnitude and phase data were collected at GE HD 1.5T. The regions evaluated included frontal white matter, grey matter, cerebrospinal fluid, putamen, caudate nucleus (CN), substantia nigra pars compacta (SNc), substantia nigra pars reticulata (SNr), and red nucleus (RN). A total number of 42 patients (12 patients without cognitive dysfunction, and 30 with cognitive dysfunction from mild to moderate degrees) and 30 control subjects were employed in the present study.
The phase radians of SNc, CN and RN in PD patients were lower than those in control subjects (P<0.05).
The phase radians can be used to estimate the brain iron deposition in PD patients, which may be helpful in the diagnosis and longitudinal monitoring of PD.
Neuroscience Bulletin 12/2009; 25(6):353-60. · 1.31 Impact Factor
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ABSTRACT: Accumulated evidence suggests a major role for the activation of the Sonic Hedgehog (SHH) signaling pathway in the development of neural crest stem cells that give rise to the sympathetic nervous system. We therefore investigated the involvement of SHH signaling in the pathogenesis of neuroblastoma, a common childhood malig-nant tumor of the sympathetic nervous system. Human neuroblastoma cell lines and a majority of primary neuroblastoma specimens showed high-level expression of the pathway targets and components, indicating persistent activation of the SHH pathway. All of the neuroblastoma cell lines we examined expressed significant levels of SHH ligand, suggesting an autocrine, ligand-dependent activation of the SHH pathway in neuroblastoma cells. Inhibition of SHH signaling by cyclopamine induced apoptosis and blocked proliferation in all major types of neuroblastoma cells, and abrogated the tumorigenicity of neuroblastoma cells. Moreover, the knockdown of GLI2 in neuroblastoma BE (2)-C and SK-N-DZ cell lines resulted in the inhibition of colony formation. Our study has revealed a molecular mechanism for the persistent activation of the SHH pathway which promotes the development of neuroblastoma, and suggests a new approach for the treatment of this childhood malignant tumor. S onic Hedgehog (SHH) is a member of the Hedgehog family of signaling proteins that were originally identified by their homology to the Drosophila melanogaster segment polarity gene Hedgehog. SHH induces signaling by binding to its receptor, Patched 1 (PTCH1), which inactivates PTCH1 and prevents it from inhibiting the transmembrane protein Smoothened (SMO). This signaling eventually results in the activation of GLI transcription factors, which, in turn, regulate the expression of many target genes that control cell growth, survival, and differentiation in a wide variety of tissues. Aberrant activation of the SHH signaling pathway has been implicated in the pathogenesis of various types of cancer. (1–3) Neuroblastoma (NB) is a childhood malignant tumor of neural crest origin, arising in the sympathetic nervous system. (4) Several lines of evidence suggest an important role for SHH signaling in regulating the development of neural crest stem cells and the sympathetic nervous system. First, inhibition of SHH signaling in vivo results in neural crest cell death. (5) Second, SHH promotes proliferation but inhibits neuronal differentiation of enteric neural crest stem cells. (6) Third, SHH signaling in neural crest stem cells is essential for the patterning and growth of facial primordia. (7) Finally, SHH signaling promotes the proliferation of postnatal sympathetic cells in culture. (8) As aberrant activation of develop-mental pathways plays a key role in cancer pathogenesis, we investigated the significance of SHH signaling in NB cell growth and tumorigenesis. Materials and Methods
Cancer Science 10/2009; 100(10):1848-1855. · 3.33 Impact Factor
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ABSTRACT: Sonic hedgehog (Shh) signaling pathway is associated with tumor development; however, the role of Shh signaling in the development of olfactory neuroblastoma (ONB) is unknown. This study aimed to investigate the relationship between the regulation of Shh signaling and the pathogenesis of ONB.
The expression of Shh signaling components was characterized by immunohistochemistry in human non-tumor olfactory epithelium and ONB specimens, and by RT-PCR and immunoblotting in human ONB cell lines. The impact of the treatment with cyclopamine (a selective inhibitor of the Shh pathway) and/or exogenous Shh on ONB cell proliferation, cycle and apoptosis was examined by MTT, soft agar colony formation and flow cytometry assays, respectively. The influence of Shh signaling on the expression of Shh signaling components and cell cycle-related regulators was determined by immunoblotting and quantitative RT-PCR, respectively.
The expression of Pacthed1, Gli1 and Gli2 was detected in 70, 70, and 65% of human ONB specimens, respectively, and in proportion of ONB cell lines, but not in non-tumor olfactory epithelium. Treatment with cyclopamine inhibited the proliferation and colony formation of ONB cells, induced ONB cell cycle arrest and apoptosis, and down-regulated the expression of Pacthed1, Gli1 and cyclin D1, but up-regulated p21 expression in vitro. These regulatory effects of cyclopamine were partially or completely erased by exogenous Shh.
These data suggest that the Shh signaling pathway is crucial for the growth of ONB.
Oncology 10/2009; 77(3-4):231-43. · 2.27 Impact Factor
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ABSTRACT: Accumulated evidence suggests a major role for the activation of the Sonic Hedgehog (SHH) signaling pathway in the development of neural crest stem cells that give rise to the sympathetic nervous system. We therefore investigated the involvement of SHH signaling in the pathogenesis of neuroblastoma, a common childhood malignant tumor of the sympathetic nervous system. Human neuroblastoma cell lines and a majority of primary neuroblastoma specimens showed high-level expression of the pathway targets and components, indicating persistent activation of the SHH pathway. All of the neuroblastoma cell lines we examined expressed significant levels of SHH ligand, suggesting an autocrine, ligand-dependent activation of the SHH pathway in neuroblastoma cells. Inhibition of SHH signaling by cyclopamine induced apoptosis and blocked proliferation in all major types of neuroblastoma cells, and abrogated the tumorigenicity of neuroblastoma cells. Moreover, the knockdown of GLI2 in neuroblastoma BE (2)-C and SK-N-DZ cell lines resulted in the inhibition of colony formation. Our study has revealed a molecular mechanism for the persistent activation of the SHH pathway which promotes the development of neuroblastoma, and suggests a new approach for the treatment of this childhood malignant tumor. (Cancer Sci 2009; 100: 1848-1855).
Cancer Science 07/2009; 100(10):1848-55. · 3.33 Impact Factor
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ABSTRACT: To explore the protective effect of doxycycline (DC) upon dopaminergic neuron in lipopolysaccharide (LPS)-induce rat model of Parkinson's disease (PD).
Sixty SD rats were randomly divided into three groups: control, LPS and doxycycline treatment. LPS was stereotatically injected into unilateral substantia nigra (SNc) of rats to establish the PD models. The damage to the substantia nigra DA neurons was observed by using tyrosine-hydroxylase (TH) immunohistochemical staining. Specific antibody OX6 (MHCII marker) was used to detect the changes in morphology and the numbers of microglia. The contents of dopamine and DOPAC in striatum were measured by high performance liquid chromatography (HPLC). Western blot were used to detect the expression of MHCII (Major histocompatibility complex class II) protein.
After doxycycline treatment, the number of TH-positive cells remaining in the SNc increased from 38% +/- 5% to 79% +/- 4% (P < 0.01). The contents of dopamine and DOPAC in striatum increased from 4.89 +/- 0.27 and 0.70 +/- 0.07 to 7.00 +/- 0.34 and 1.10 +/- 0.10 respectively (P < 0.01); there was a significant decrease in rotational asymmetry in the doxycycline treatment group [(80 +/- 12) turns/30 min] when compared to the LPS group [(208 +/- 14) turns/30 min] (P < 0.01). However, the number of MHCII-positive microglia decreased significantly (LPS group: 835 +/- 82 vs doxycycline treatment group: 354 +/- 59, P < 0.01) after doxycycline treatment. Western blot were used to detect the expression of MHCII protein. The results showed that the expression of MHCII protein on microglia of LPS group increased significantly compared to the control group, but the expression of MHCII protein were inhibited significantly after doxycycline treatment in the doxycycline treatment group, as compared to the LPS group.
Doxycycline might inhibit dopaminergic neuron degeneration by down-regulating the MHCII expression on microglia.
Zhonghua yi xue za zhi 06/2009; 89(19):1346-50.
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ABSTRACT: Intestinal pacing (IP) has been previously shown to delay gastric emptying and reduce food intake in animals. The aims of this study were to investigate the effect and mechanism of IP on nutrient absorption in healthy volunteers.
Twelve healthy volunteers (six men, six women) were involved in a two-session (one session without IP and one with IP) study. At the beginning of each session, a nasal-duodenal feeding tube, with two ring electrodes (used for IP) on the tip of the tube, was incubated into the duodenum under endoscopy. After a complete recovery from the incubation, the duodenum was infused via the feeding tube with 150 ml 30% intralipid + 25 g D-xylose within 30 min, and the stool was collected for 24 h for the analysis of fecal lipid during which a controlled meal was taken. Then 100 ml 1mCi(99)Tc-labeled non-absorbable solution was infused within 3 min. The subject was asked to lie under a gamma camera for at least 1 h for the measurement of small bowel transit. The movement of isotopes was monitored by gamma camera at an interval of 10 s. The first appearance of isotopes in the cecum was considered as small intestinal transit time. The order of the two sessions was randomized and 1 week apart. In the IP session, intestinal pacing was performed via the pair of the ring electrodes for 2 h initiated at the beginning of infusion with a pacing frequency of 13 pulses/min, pulse width of 300 ms and amplitude of 5 mA.
(1) IP significantly reduced lipid and D-xylose absorption. The fecal lipid was 6.6 +/- 4.6 g without IP and almost doubled with IP (11.1 +/- 6.5 g, P = 0.047). Similarly, the D-xylose in urine was 3.46 +/- 2.22 g with IP, which was significantly lower than that without IP (6.63 +/- 5.06 g, p = 0.049). (2) IP accelerated intestinal transit. The transit time was 39 +/- 17 min in the control session and reduced to 28 +/- 10 min in the IP session (p < 0.03). (3) Diarrhea was reported in one subject without IP but in six subjects with IP (p < 0.05).
The increased fecal lipid and induction of diarrhea with intestinal pacing suggest that intestinal pacing is capable of inducing malabsorption. This effect maybe contributed to the acceleration of intestinal transit.
Obesity Surgery 08/2008; 19(2):196-201. · 3.29 Impact Factor
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ABSTRACT: Vascular endothelial growth factor (VEGF) is a specific angiogenic peptide, which has been identified to play a critical role in neurodegeneration, and has beneficial effects on neurons. In this study, we investigated whether neurodegeneration in a rat model of Parkinson disease could be prevented by VEGF gene transfer mediated by adeno-associated virus (AAV) vectors. Our results demonstrated that a single injection of a VEGF-expressing AAV vector into striatum improved the rotational behavior of rat Parkinson disease models, and promoted the survival of dopaminergic neurons and fibers. Meanwhile, AAV-VEGF injection significantly increased the reactive astrocytes and the levels of glial cell line-derived neurotrophic factor in striatum, but did not induce extra angiogenesis and remarkable disorder of blood-brain barrier. We thus conclude that intrastriatal delivery of VEGF gene mediated by AAV has favorable effects on the dopaminergic neurons in a rat Parkinson disease model.
Neuroscience Letters 07/2007; 421(3):239-44. · 2.11 Impact Factor
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ABSTRACT: To explore the role of proteolytic stress induced by environmental toxins in degeneration and death of dopaminergic neurons.
Nerve growth factor-treated-rat adrenal pheochromocytoma cells of the line PC12 were co-incubated with 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenylpyridinium ion (MPP(+)), and rotenone for 24 hours. MTT assay was used to measure the cell viability induced by these neurotoxins with different concentrations. The expression levels of alpha-synuclein and ubiquited proteins in every group were observed with laser scanning confocal technique. The enzymatic activities of three main hydrolases in proteasome were measured by detection of the fluorophore of various cleft synthetic fluorogenic peptides.
6-OHDA, MPP(+), and rotenone decreased the activity of PC12 cells dose-dependently. Co-incubated with 100 micromol/L 6-OHDA, 75 micromol/L MPP(+), and 20 nmol/L rotenone, the activity of PC12 cells decreased by 52%, 44%, and 40% respectively. Immunofluorescence double labeling confirmed the overexpression of alpha-synuclein and ubiquitin and pellet accumulation in the cytoplasm induced by three toxins. Compared with those in the control group, the trypsin-like, chymotrypsin-like, and PgH-like activities of proteasome were markedly decreased in the MPP(+) and rotenone groups (all P < 0.05) and slightly decreased in the 6-OHDA 100 micromol/L group (all P > 0.05), but after the exposure to 6-OHDA 200 micromol/L for 24 h, the activities of the three enzymes decreased rapidly, the activities of the three enzymes were 7.2 +/- 0.6, 79.6 +/- 2.7 and 4.2 +/- 0.5 FU/100 microg respectively (vs 13.9 +/- 1.8, 99.3 +/- 5.2, and 6.9 +/- 0.6 FU/100 microg respectively in the control group, all P < 0.01).
Environmental toxins induce proteolytic stress marked by dysfunction of ubiquitin proteasome and accumulation of alpha-synuclein and ubiquited proteins.
Zhonghua yi xue za zhi 05/2007; 87(17):1190-4.
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ABSTRACT: Objective To observe the influence of rotenone on the distribution of alpha-synuclein (ASN) in rat model of Parkinson's disease (PD). Methods Wistar rats were randomly divided into two groups and received 2 mg/kg rotenone (s.c.) or sunflower oil (as control group) for about 4 weeks. The hippocampus, substantia nigra and striatum of brain were observed. Hematoxylin and eosin stain were used to observe the Lewy body like inclusion. The expression of tyrosine hydroxylase (TH) or ASN protein was determined by anti-TH or anti-alpha-synuclein immunohistochemistry, respectively. Results In control rats, ASN protein distributed widely in brain, especially in hippocampus, cortex and striatum. Rotenone obviously increased TH positive neurons and fibers loss in substantia nigra and striatum (P < 0.05). In rotenone treated rats, ASN positive cells increased in global brain but not distributed in an even manner. In substantia nigra, ASN positive stuff was found aggregate in both cytoplasm and nucleus, and some formed spherical inclusion; in striatum, ASN positive neurites end aggregated and agglomerated around neurons; and in hippocampus, few dot-like ASN were aggregated in cell body, and no notable change was found in nucleus. Conclusion In rotenone administrated PD rats, ASN protein aggregated in several brain regions but most obviously in striatum and substantia nigra, and the distribution region of ASN was changed from peri-synapse to the cytoplasm and nucleus of dopaminergic neuron.
Neuroscience Bulletin 09/2006; 22(5):288-93. · 1.31 Impact Factor
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ABSTRACT: To evaluate the protective effect of adenovirus mediated vascular endothelial growth factor 165 (VEGF165) gene transfer on dopaminergic neurons in Parkinson disease (PD).
Adenovirus vector coding VEGF165 (Ad-VEGF165) was injected into the striate bodies of 16 SD rats, and adenovirus Ad-LacZ was injected into 25 rats and phosphate-buffered saline (PBS) was injected into 16 rats as controls. Then 6-hydroxydopamine (6-OHDA) was injected to establish PD model. X-gal staining was used to detect the expression of the report gene LacZ in the brain of the Ad-LacZ group 3 d, 2 w, and 6 w after injection, 3 rats in each time point. RT-PCR was used to detect the VEGF165 mRNA expression in the striate body of the rats of the 3 groups 2 weeks after injection, 3 rats for each group. Western blotting was performed to check the protein expression of VEGF165 in the striate bodies of the rats of the 3 groups 2 weeks after injection, 3 rats for each group. A certain numbers of rats in each group underwent rotational behavior analysis 1, 2, and 6 weeks after the 6-OHDA injection. Immunohistochemistry was used to examine the number of tyrosine hydroxylase (TH) positive neuron, density of TH-positive fiber in striate body and black substance, laminin-positive vessel density, and glial fibrillary acidic protein (GFAP) positive glial cells. High performance liquid chromatography-electric-chemical discharge (HPLC-ECD) was performed to detect the contents of dopamine (DA) and its metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the striatum.
Beta-gal was expressed in the striate bodies of all Ad-LacZ transfected rats, showing the successful transfection of LacZ gene. The mRNA expression and protein expression of VEGF165 in the striate body were significantly higher in the Ad-VEGF165 group than in the other 2 groups. The apomorphine-induced rotation number in the Ad-VEGF165 group was 8.3 turns/min +/- 8.7 turns/min 1 week after the transfection, then gradually decreased, and became 5.0 turns/min +/- 4.4 turns/min 6 weeks after. The rotation numbers of the Ad-LacZ and PBS group were 14.7 turns/min +/- 11.2 turns/min and 13.9 turns/min +/- 8.3 turns/min respectively 1 week after the injection, then increased gradually, and became 20.2 turns/min +/- 13.6 turns/min and 21.8 turns/min +/- 11.8 turns/min respectively 6 weeks later, all significantly higher than those of the Ad-LacZ group (all P < 0.01). The ratios of TH-positive cells in the black substance in the transfected side was 0.42 +/- 0.11, and the density of fibers in the striate body of the transfected side to that of the contralateral side was 0.56 +/- 0.10 in the Ad-VEGF165 group, both significantly higher than those of the Ad-LacZ group (0.20 +/- 0.10 and 0.28 +/- 0.09) and PBS group (0.22 +/- 0.13 and 0.24 +/- 0.08), (all P < 0.01). The ratio of laminin-positive vessel density of the transfected side to that of the contralateral side in the Ad-VEGF165 group was 2.09 +/- 0.42, and the ratio of GFAP-positive glial cells of the striate body of the transfected side to that of the contralateral side was 2.77 +/- 1.21 in the Ad-VEGF165 group, both significantly higher than those in the Ad-LacZ group (1.01 +/- 0.16 and 1.64 +/- 0.28) and the PBS group (1.04 +/- 0.09 and 1.56 +/- 0.62) (P < 0.01 and 0.05). HPLC-ECD showed that the contents of DA, HAV, and DOPAC of the striate body at the destroyed side in the Ad-VEGF165 group were all significantly higher than those in the other 2 groups (all P < 0.01). The ratios to the DA, DOPAC, and HVA of the destroyed side striate body to those of the contralateral side in the Ad-VEGF165 group was 0.35 +/- 0.11, 0.46 +/- 0.09, and 0.38 +/- 0.09 respectively, all significantly higher than those in the Ad-LacZ group (0.17 +/- 0.15, 0.21 +/- 0.07, and 0.16 +/- 0.05) and PBS group (0.19 +/- 0.06, 0.20 +/- 0.09, 0.14 +/- 0.03) (all P < 0.01).
Gene transfer of Ad-VEGF165 has a protective effect on the dopaminergic neurons of PD. The proliferation of vessels and glial cells induced by VEGF may involve in the process of neuroprotection to the dopaminergic neurons of PD.
Zhonghua yi xue za zhi 08/2006; 86(29):2054-9.
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ABSTRACT: The aims of this study were to investigate the effects and mechanisms of a novel method of gastric electrical stimulation on the prevention of vasopressin-induced emetic response and gastric dysrhythmias.
Fifteen dogs (10 normal, 5 vagotomized) chronically implanted with gastric serosal electrodes were used in a 3-session study (vasopressin, vasopressin plus 2-channel stimulation [DCS], and vasopressin plus dual-pulse stimulation [DPS]).
Vasopressin induced gastric dysrhythmias and motion sickness-like symptoms (P < .05) and these effects were blocked partially with vagotomy. Both methods of DCS and DPS were capable of preventing vasopressin-induced gastric dysrhythmias (P < .05) and motion sickness-like symptoms (P < .05). The antiemetic effects of the proposed methods of DCS and DPS were abolished by vagotomy but their antidysrhythmic effects were not blocked by vagotomy.
DCS and DPS are able to reduce vasopressin-induced gastric dysrhythmia and symptoms of nausea and vomiting. The vagal pathway is involved in the antiemetic effect but not the antidysrhythmic effect of the proposed methods of stimulation.
The American Journal of Surgery 02/2006; 191(2):255-61. · 2.78 Impact Factor
