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  • Gossypol Acetic Acid Prevents Oxidative Stress-Induced Retinal Pigment Epithelial Necrosis by Regulating the FoxO3/Sestrin2 Pathway. 25802279

    The late stage of dry age-related macular degeneration (AMD), or geographic atrophy (GA), is characterized by extensive retinal pigment epithelial (RPE) cell death, and a cure is not available currently. We have recently demonstrated that RPE cells die from necrosis in response to oxidative stress, providing a potential novel mechanism for RPE death in AMD. In this study, we screened U.S. Food and Drug Administration-approved natural compounds and identified gossypol acetic acid (GAA) as a potent inhibitor of oxidative stress-induced RPE cell death. GAA induces antioxidative response and inhibits accumulation of excessive reactive oxygen species in cells, through which it prevents the activation of intrinsic necrotic pathway in response to oxidative stress. Sestrin2 (SESN2) is found to mediate GAA function in antioxidative response and RPE survival upon oxidative stress. Moreover, Forkhead box O3 transcription factor (FoxO3) is further found to be required for GAA-mediated SESN2 expression and RPE survival. Mechanistically, GAA promotes FoxO3 nuclear translocation and binding to the SESN2 enhancer, which in turn increases its transcriptional activity. Taken together, we have identified GAA as a potent inhibitor of oxidative stress-induced RPE necrosis by regulating the FoxO3/SESN2 pathway. This study may have significant implications in the therapeutics of age-related diseases, especially GA.
    Tipo de documento:
    Referencia
    Referencia del producto:
    17-371
    Nombre del producto:
    EZ-ChIP™
  • Nanoporous peptide particles for encapsulating and releasing neurotrophic factors in an animal model of neurodegeneration. 22610659

    Neurotrophin-BDNF can be effectively encapsulated in nanoporous poly(L-glutamic acid) particles prepared via mesoporous silica templating. The loaded BDNF can be released in a sustained manner with retained biological activity. Animal experiments demonstrate the released BDNF can efficiently rescue the auditory neurons (as indicated by the arrows) in the cochlea of guinea pigs with sensorineural hearing loss.
    Tipo de documento:
    Referencia
    Referencia del producto:
    S7100
    Nombre del producto:
    ApopTag® Peroxidase In Situ Apoptosis Detection Kit
  • Transfer of sulfamethazine from contaminated beeswax to honey. 20499935

    A liquid chromatographic tandem mass spectrometric method for the determination of sulfa drugs in beeswax was developed. When performing residue control on beeswax intended for the fabrication of wax foundations, residues of sulfonamides were found. A migration test was set up to study whether sulfonamide-containing beeswax could lead to the contamination of honey. The higher the concentration of sulfamethazine doped in the wax, the higher was the concentration of sulfamethazine found in the honey. The maximum transfer was 15.6, 56.9, and 29.5% of the initial amount spiked in the wax foundation. In a second experiment, the percentage of sulfamethazine migrating from medicated winter feed to beeswax in relation to the concentration in the syrup and the contact time was studied. The maximum transfer of sulfamethazine from medicated sucrose syrup to beeswax was 3.1%.
    Tipo de documento:
    Referencia
    Referencia del producto:
    S7903
    Nombre del producto:
    Amplifluor® UniPrimer II Fluorescein
  • Epidermal growth factor upregulates serotonin transporter and its association with visceral hypersensitivity in irritable bowel syndrome. 25309082

    To investigate the role of epidermal growth factor (EGF) in visceral hypersensitivity and its effect on the serotonin transporter (SERT).A rat model for visceral hypersensitivity was established by intra-colonic infusion of 0.5% acetic acid in 10-d-old Sprague-Dawley rats. The visceral sensitivity was assessed by observing the abdominal withdrawal reflex and recording electromyographic activity of the external oblique muscle in response to colorectal distension. An enzyme-linked immunosorbent assay was used to measure the EGF levels in plasma and colonic tissues. SERT mRNA expression was detected by real-time PCR while protein level was determined by Western blot. The correlation between EGF and SERT levels in colon tissues was analyzed by Pearson's correlation analysis. SERT function was examined by tritiated serotonin (5-HT) uptake experiments. Rat intestinal epithelial cells (IEC-6) were used to examine the EGF regulatory effect on SERT expression and function via the EGF receptor (EGFR).EGF levels were significantly lower in the rats with visceral hypersensitivity as measured in plasma (2.639 ± 0.107 ng/mL vs 4.066 ± 0.573 ng/mL, P less than 0.01) and in colonic tissue (3.244 ± 0.135 ng/100 mg vs 3.582 ± 0.197 ng/100 mg colon tissue, P less than 0.01) compared with controls. Moreover, the EGF levels were positively correlated with SERT levels (r = 0.820, P less than 0.01). EGF displayed dose- and time-dependent increased SERT gene expressions in IEC-6 cells. An EGFR kinase inhibitor inhibited the effect of EGF on SERT gene upregulation. SERT activity was enhanced following treatment with EGF (592.908 ± 31.515 fmol/min per milligram vs 316.789 ± 85.652 fmol/min per milligram protein, P less than 0.05) and blocked by the EGFR kinase inhibitor in IEC-6 cells (590.274 ± 25.954 fmol/min per milligram vs 367.834 ± 120.307 fmol/min per milligram protein, P less than 0.05).A decrease in EGF levels may contribute to the formation of visceral hypersensitivity through downregulation of SERT-mediated 5-HT uptake into enterocytes.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AB9726
    Nombre del producto:
    Anti-Serotonin Transporter Antibody
  • Oxidized Low-Density Lipoprotein-Induced Matrix Metalloproteinase-9 Expression via PKC-delta/p42/p44 MAPK/Elk-1 Cascade in Brain Astrocytes. 19554388

    After ischemic injury to brain, disruption of the blood-brain barrier (BBB) raises the possibility of exposing the central nervous system (CNS) to oxidized low-density lipoprotein (oxLDL), a risk factor implicated in neurodegenerative diseases. Matrix metalloproteinases (MMPs), especially MMP-9, contribute to extracellular matrix (ECM) remodeling during the CNS diseases. However, the molecular mechanisms underlying oxLDL-induced MMP-9 expression in astrocytes remained unclear. Here, we reported that oxLDL induced MMP-9 expression via a PKC-delta/p42/p44 MAPK-dependent Elk-1 activation in rat brain astrocyte (RBA)-1 cells, revealed by gelatin zymography, RT-PCR, and Western blotting analyses. These responses were attenuated by pretreatment with pharmacological inhibitors and transfection with dominant negative mutants. Moreover, Elk-1-mediated MMP-9 gene transcription was confirmed by transfection with an Elk-1 binding site-mutated MMP-9 promoter construct (mt-Ets-MMP9), which blocked oxLDL-stimulated MMP-9 luciferase activity. Understanding the regulatory mechanisms by which oxLDL induced MMP-9 expression in astrocytes might provide a new therapeutic strategy of brain diseases.
    Tipo de documento:
    Referencia
    Referencia del producto:
    06-866
    Nombre del producto:
    Anti-acetyl-Histone H4 Antibody
  • Effect of the 5-HT4 receptor and serotonin transporter on visceral hypersensitivity in rats. 22832600

    Visceral hypersensitivity plays an important role in motor and sensory abnormalities associated with irritable bowel syndrome, but the underlying mechanisms are not fully understood. The present study was designed to evaluate the expression of the 5-HT(4) receptor and the serotonin transporter (SERT) as well as their roles in chronic visceral hypersensitivity using a rat model. Neonatal male Sprague-Dawley rats received intracolonic injections of 0.5% acetic acid (0.3-0.5 mL at different times) between postnatal days 8 and 21 to establish an animal model of visceral hypersensitivity. On day 43, the threshold intensity for a visually identifiable contraction of the abdominal wall and body arching were recorded during rectal distention. Histological evaluation and the myeloperoxidase activity assay were performed to determine the severity of inflammation. The 5-HT(4) receptor and SERT expression of the ascending colon were monitored using immunohistochemistry and Western blot analyses; the plasma 5-HT levels were measured using an ELISA method. As expected, transient colonic irritation at the neonatal stage led to visceral hypersensitivity, but no mucosal inflammation was later detected during adulthood. Using this model, we found reduced SERT expression (0.298 ± 0.038 vs 0.634 ± 0.200, P less than 0.05) and increased 5-HT(4) receptor expression (0.308 ± 0.017 vs 0.298 ± 0.021, P less than 0.05). Treatment with fluoxetine (10 mg · kg(-1) · day(-1), days 36-42), tegaserod (1 mg · kg(-1) · day(-1), day 43), or the combination of both, reduced visceral hypersensitivity and plasma 5-HT levels. Fluoxetine treatment increased 5-HT(4) receptor expression (0.322 ± 0.020 vs 0.308 ± 0.017, P less than 0.01) but not SERT expression (0.219 ± 0.039 vs 0.298 ± 0.038, P = 0.654). These results indicate that both the 5-HT(4) receptor and SERT play a role in the pathogenesis of visceral hypersensitivity, and its mechanism may be involved in the local 5-HT level.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AB1594P
    Nombre del producto:
    Anti-Serotonin Transporter Antibody
  • Differential effects of selective and non-selective inhibition of nitric oxide synthase on the expression and activity of cyclooxygenase-2 during gastric ulcer healing. 16600210

    Nitric oxide synthases (NOS) and cyclooxygenase-2 (COX-2) are important enzymes involved in ulcer healing but interactions between them have not been clearly defined. The aim of this study was to investigate the effects of selective or non-selective inhibition of NOS on the expression and activity of COX-2 during healing of acetic acid-induced gastric ulcers in rats. N-[3-(aminomethyl)benzyl] acetamidine (1400 W), a potent selective inhibitor of inducible nitric oxide synthase (iNOS), at a dose of 0.1 mg/kg/day, was found to reduce the ulcer sizes at day 3 and 7 post-ulcer induction. On the other hand, 15 mg/kg/day of NG-nitro-L-arginine methyl ester (L-NAME), a non-selective NOS inhibitor that suppresses both iNOS and endothelial nitric oxide synthase (eNOS), enlarged the ulcer sizes over the same time periods. The expression of COX-2 and COX activity, together with NF-kappaB activation in the ulcer tissues were down-regulated by L-NAME but not 1400 W. It is concluded that iNOS may contribute to ulcer formation while COX-2 and eNOS promote ulcer healing. eNOS enhances COX-2 expression possibly through the activation of NF-kappaB.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB3026
    Nombre del producto:
    Anti-NFκB Antibody, p65 subunit, active subunit, clone 12H11
  • Using small molecule reagents to selectively modify epitopes based on their conformation. 22436143

    PrP(Sc) is an infectious protein. The only experimentally verified difference between PrP(Sc) and its normal cellular isoform (PrP(C)) is conformational. This work describes an approach to determining the presence of surface exposed or sequestered amino acids present in the PrP(Sc) isoform. The N-hydroxysuccinimide esters of acetic acid and 4-trimethylammoniumbutyric acid were synthesized and reacted with detergent-solubilized brain extracts from Me7-infected mice, uninfected mice, 263K-infected hamsters or uninfected hamsters. These reaction mixtures were analyzed by western blots probed with the antibodies 3F4, 6D11, 7D9, AG4, AH6, GE8 or MAB5424. The 3F4, 6D11, AH6, and GE8 antibodies recognize an epitope that is encrypted in the PrP(Sc) isoform, but exposed in the PrP(C) isoform. These reagents permit the detection of prion infected brain extracts without the need for proteinase K digestion. In addition they can be used, with an appropriate antibody, to determine which amino acids of PrP(Sc) are exposed on the surface and which are encrypted, thus providing useful structural information. This approach was used to distinguish between the 263K and drowsy strains of hamster-adapted scrapie without the use of proteinase K.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB5424
    Nombre del producto:
    Anti-Prion Protein Antibody
  • Water in Acetic acid

    Tipo de documento:
    Aplicación
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo