Biomedical subjects

Sufen Yang

Publications and source records attributed to Sufen Yang.

6 recordsLinked to original sources

PubMed2006

Pituitary adenylate cyclase-activating polypeptide (PACAP) 38 and PACAP4-6 are neuroprotective through inhibition of NADPH oxidase: potent regulators of microglia-mediated oxidative stress.

Microglial activation is implicated in the progressive nature of numerous neurodegenerative diseases, including Parkinson's disease. Using primary rat mesencephalic neuron-glia cultures, we found that pituitary adenylate cyclase-activating polypeptide (PACAP) 38, PACAP27, and its internal peptide, Gly-Ile-Phe (GIF; PACAP4-6), are neuroprotective at 10(-13) M against lipopolysaccharide (LPS)-induced dopaminergic (DA) neurotoxicity, as determined by [(3)H]DA uptake and the number of tyrosine hydroxylase-immunoreactive neurons. PACAP38 and GIF also protected against 1-methyl-4-phenylpyridinium(+)-induced neurotoxicity but only in cultures containing microglia. PACAP38 and GIF ameliorated the production of microglia-derived reactive oxygen species (ROS), where both LPS- and phorbol 12-myristate 13-acetate-induced superoxide and intracellular ROS were inhibited. The critical role of NADPH oxidase for GIF and PACAP38 neuroprotection against LPS-induced DA neurotoxicity was demonstrated using neuron-glia cultures from mice deficient in NADPH oxidase (PHOX(-/-)), where PACAP38 and GIF reduced tumor necrosis factor alpha production and were neuroprotective only in PHOX(+/+) cultures and not in PHOX(-/-) cultures. Pretreatment with PACAP6-38 (3 microM; PACAP-specific receptor antagonist) was unable to attenuate PACAP38, PACAP27, or GIF (10(-13) M) neuroprotection. PACAP38 and GIF (10(-13) M) failed to induce cAMP in neuronglia cultures, supporting that the neuroprotective effect was independent of traditional high-affinity PACAP receptors. Pharmacophore analysis revealed that GIF shares common chemical properties (hydrogen bond acceptor, positive ionizable, and hydrophobic regions) with other subpicomolar-acting compounds known to inhibit NADPH oxidase: naloxone, dextromethorphan, and Gly-Gly-Phe. These results indicate a common high-affinity site of action across numerous diverse peptides and compounds, revealing a basic neuropeptide regulatory mechanism that inhibits microglia-derived oxidative stress and promotes neuron survival.

Animals↗

PubMed2005

Iron-catalyzed propylene epoxidation by nitrous oxide: studies on the effects of alkali metal salts.

SBA-15-supported iron catalysts with and without alkali metal salt modifications were studied for propylene oxidation by nitrous oxide. The reaction route could be dramatically changed from allylic oxidation to epoxidation by modification of the FeOx/SBA-15 catalyst with alkali metal salts. The KCl-1 wt % FeOx/SBA-15 (K/Fe = 5) catalyst exhibited the best catalytic performances for propylene epoxidation, over which ca. 50% propylene oxide selectivity could be gained at a 10% propylene conversion at 648 K. Characterizations with diffuse reflectance UV-Vis, XANES, and Raman spectroscopic techniques revealed that the modification with KCl increased the dispersion of the iron species and changed the local coordination of iron into a tetrahedral configuration on the inner surface of SBA-15. This tetrahedrally coordinated iron site, which was probably stabilized by potassium ions, was proposed to account for the epoxidation of propylene by nitrous oxide. At the same time, the reactivity of lattice oxygen was inhibited, and the acidity of the FeOx/SBA-15 was eliminated. These changes should also contribute to the increase in the selectivity to propylene oxide. The counteranions in the alkali metal salts exerted a significant influence on the catalytic behaviors probably via an electronic effect.

Journal Article↗

PubMed2004

Valproate pretreatment protects dopaminergic neurons from LPS-induced neurotoxicity in rat primary midbrain cultures: role of microglia.

Parkinson's disease is a neurodegenerative disorder characterized by progressive degeneration of dopaminergic (DA) neurons in the substantia nigra. Accumulating evidence supports the notion that neuroinflammation is involved in the pathogenesis of this disease. Valproate (VPA) has long been used for the treatment of seizures and bipolar mood disorder. In vivo and in vitro studies have demonstrated that VPA has neuroprotective and neurotrophic actions. In this study, using primary neuron-glia cultures from rat midbrain, we demonstrated that VPA is a potent neuroprotective agent against lipopolysaccharide (LPS)-induced neurotoxicity. Results showed that pretreatment with 0.6 mM VPA for 48 h robustly attenuated LPS-induced degeneration of dopaminergic neurons as determined by [(3)H] dopamine uptake and counting of the number of TH-ir neurons. The neuroprotective effect of VPA was concentration-dependent and was mediated, at least in part, through a decrease in levels of pro-inflammatory factors released from activated microglia. Specifically, LPS-induced increase in the release of TNFa, NO, and intracellular reactive oxygen species was markedly reduced in cultures pretreated with VPA. These anti-inflammatory effects of VPA were time and concentration-dependent correlated with a decrease in the number of microglia. Thus, our results demonstrate that protracted VPA pretreatment protects dopaminergic neurons from LPS-induced neurotoxicity through a reduction in levels of released pro-inflammatory factors, and further suggest that these anti-inflammatory effects may be contributed by VPA-induced reduction of microglia cell number. Taken together, our study reinforces the view that VPA may have utility in treating Parkinson's disease.

Analysis of Variance↗

PubMed2004

Environmental mycological study and respiratory disease investigation in tussah silk processing workers.

This study presents the results of an investigation of respiratory symptoms, pulmonary function and chest X-ray examinations, and analysis of antibodies to fungi of 197 tussah silk-processing workers and 40 control workers. An industrial hygiene survey and environmental mycological studies were also conducted. The dust concentrations in tussah silk processing workshops were less than 5.1 mg/m(3) on average, with a maximum of 7.8 mg/m(3) below the national health limit of 10 mg/m(3). Most dusts in all tussah silk processing workshops contained less than 1.2% silica. Numbers of isolated fungi in tussah silk processing workshops [755-6,544 cfu/m(3) (colony forming unit/m(3)), were significantly higher than those in control environments (63-472 cfu/m(3)). The prevalences of respiratory symptoms in tussah silk processing workers were higher than those in control workers. The prevalences of respiratory symptoms in exposed male non-smoking workers were 44.4% with chronic cough, and 38.9% with chronic phlegm respectively, which were significantly higher than those (12.5%, 12.5% respectively) in male non-smoking control workers (p<0.05). The prevalences in exposed male smoking workers were 42.9% with dyspnea, and 38.1% with chest tightness respectively, which were significantly higher than those (16.7%, 8.3% respectively) in male smoking control workers (p<0.01). The prevalences of respiratory symptoms in exposed female workers were 25.3% with chronic cough, 38.0% with chronic phlegm, 31.0% with dyspnea, and 29.1% with chest tightness respectively, which were significantly higher than those (10.0%, 10.0%, 10.0%, 5.0% respectively) in female control workers (p<0.01). Fifteen exposed workers often suffered from fever. Five X-rays were abnormal and four cases had nodular or patchy shadows. The prevalences of pulmonary function abnormalities in the exposed female group were significantly higher than those in control groups (p<0.01). The OD(450 nm) values for antibodies to fungi in tussah silk processing workers were significantly higher than those of control workers (p<0.05). The positive rates of anti-fungal antibodies in tussah silk-processing workers were also significantly higher than those of control workers (p<0.01). The results suggested that fungi might be one of the main allergens in respiratory diseases in the tussah silk processing workers.

Adult↗

PubMed2003

Environmental mycological study and respiratory disease investigation in fur-processing workers.

This paper presents the results of an investigation of respiratory symptoms, chest X-ray examinations, and analysis of antibodies to fungi of 138 fur-processing workers and 40 control workers. Industrial hygiene survey and environmental mycological studies were also conducted. The dust concentrations in fur processing workshops (1.8-6.7 mg/m3) were below the national health limit (10 mg/m3). Most dusts in all fur processing workshops contained less than 2.0% silica. Numbers of isolated fungi in fur processing workshops [629-3,681 cfu/m3 (colony forming unit/m3)] were significantly higher than those in control environments (63-503 cfu/m3). The prevalences of respiratory symptoms in fur processing workers were higher than those in control workers, especially among female exposed workers. The prevalences of the symptoms in female exposed workers were 37.9% with chronic cough, 28.4% with chronic phlegm, 10.5% with dyspnea, 22.1% with chest tightness, and 4.2% with fever. Seven cases showed abnormalities in chest X-ray examinations. The OD450nm values for antibodies to fungi in fur processing workers were significantly higher than those in control workers (P<0.05). The prevalences of positive anti-fungi antibodies in fur-processing workers were also significantly higher than those in control workers (p<0.01). The results suggested that fungi might be one of the main allergens in respiratory diseases in fur processing workers.

Adult↗

PubMed2002

[Study on occupational respiratory diseases in fur-processing workers].

OBJECTIVE: To study the respiratory system injury in fur processing environment. METHODS: Environmental fungal survey was conducted in the fur processing procedures. Investigation of respiratory symptoms and chest X-ray examination were also carried out in 138 fur processing workers and 40 control workers. At the same time, the serum antibodies to fungi were analyzed by ELISA. RESULTS: Fungal number(629-3,681 cfu/m3) in fur processing procedures was much higher than those in the control environment. Cladosporium and Alternaria were the leading strains of fungi in fur processing procedures. The rates of respiratory symptoms(cough, sputum, chest tightness, dyspnea, and fever) in fur processing workers were higher than those in the control workers. The rates of the symptoms in female workers were 37.9%, 28.4%, 10.5%, 22.1%, 4.2%, respectively. Abnormalities of chest X ray were found in 7 workers. The serum antibodies to Cladosporium and Alternaria(A450 nm 0.631, 0.724, respectively) in fur workers were significantly higher than those in the control workers(P < 0.05). The positive rates of the antibodies to Cladosporium and Alternaria(44.2%, 42.8%) were significantly higher than those in the control workers(P < 0.01). CONCLUSION: Cladosporium and Alternaria may be the pathogens of occupational respiratory diseases in fur processing workers.

Alternaria↗