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  1. Fulltext γ-Secretase Inhibitors and Modulators Induce Distinct Conformational Changes in the Active Sites of γ-Secretase and Signal Peptide Peptidase
    Gertsik N, Chau DM, Li YM
    ACS Chem. Biol., 2015 Aug 21;10(8):1925-31.
    PMID: 26030233 DOI: 10.1021/acschembio.5b00321
    γ-Secretase inhibitors (GSIs) and modulators (GSMs) are at the frontline of cancer and Alzheimer's disease research, respectively. While both are therapeutically promising, not much is known about their interactions with proteins other than γ-secretase. Signal peptide peptidase (SPP), like γ-secretase, is a multispan transmembrane aspartyl protease that catalyzes regulated intramembrane proteolysis. We used active site-directed photophore walking probes to study the effects of different GSIs and GSMs on the active sites of γ-secretase and SPP and found that nontransition state GSIs inhibit labeling of γ-secretase by activity-based probes but enhance labeling of SPP. The opposite is true of GSMs, which have little effect on the labeling of γ-secretase but diminish labeling of SPP. These results demonstrate that GSIs and GSMs are altering the structure of not only γ-secretase but also SPP, leading to potential changes in enzyme activity and specificity that may impact the clinical outcomes of these molecules.
    Matched MeSH terms: Benzophenones/chemistry; Aspartic Acid Endopeptidases/chemistry*; Amyloid Precursor Protein Secretases/chemistry*; Small Molecule Libraries/chemistry*
  2. γ-Fe2O3 nanoparticles filled polyvinyl alcohol as potential biomaterial for tissue engineering scaffold
    Ngadiman NH, Idris A, Irfan M, Kurniawan D, Yusof NM, Nasiri R
    J Mech Behav Biomed Mater, 2015 Sep;49:90-104.
    PMID: 26002419 DOI: 10.1016/j.jmbbm.2015.04.029
    Maghemite (γ-Fe2O3) nanoparticle with its unique magnetic properties is recently known to enhance the cell growth rate. In this study, γ-Fe2O3 is mixed into polyvinyl alcohol (PVA) matrix and then electrospun to form nanofibers. Design of experiments was used to determine the optimum parameter settings for the electrospinning process so as to produce elctrospun mats with the preferred characteristics such as good morphology, Young's modulus and porosity. The input factors of the electrospinnning process were nanoparticles content (1-5%), voltage (25-35 kV), and flow rate (1-3 ml/h) while the responses considered were Young's modulus and porosity. Empirical models for both responses as a function of the input factors were developed and the optimum input factors setting were determined, and found to be at 5% nanoparticle content, 35 kV voltage, and 1 ml/h volume flow rate. The characteristics and performance of the optimum PVA/γ-Fe2O3 nanofiber mats were compared with those of neat PVA nanofiber mats in terms of morphology, thermal properties, and hydrophilicity. The PVA/γ-Fe2O3 nanofiber mats exhibited higher fiber diameter and surface roughness yet similar thermal properties and hydrophilicity compared to neat PVA PVA/γ-Fe2O3 nanofiber mats. Biocompatibility test by exposing the nanofiber mats with human blood cells was performed. In terms of clotting time, the PVA/γ-Fe2O3 nanofibers exhibited similar behavior with neat PVA. The PVA/γ-Fe2O3 nanofibers also showed higher cells proliferation rate when MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was done using human skin fibroblast cells. Thus, the PVA/γ-Fe2O3 electrospun nanofibers can be a promising biomaterial for tissue engineering scaffolds.
    Matched MeSH terms: Biocompatible Materials/chemistry*; Ferric Compounds/chemistry*; Polyvinyl Alcohol/chemistry*; Nanoparticles/chemistry*; Tissue Scaffolds/chemistry*; Nanofibers/chemistry
  3. β-Sitosterol from Ifloga spicata (Forssk.) Sch. Bip. as potential anti-leishmanial agent against leishmania tropica: Docking and molecular insights
    Majid Shah S, Ullah F, Ayaz M, Sadiq A, Hussain S, Ali Shah AU, et al.
    Steroids, 2019 08;148:56-62.
    PMID: 31085212 DOI: 10.1016/j.steroids.2019.05.001
    The current study was aimed to evaluate the anti-leishmanial potentials of β-sitosterol isolated from Ifloga spicata. The anti-leishmanial potential of β-sitosterol is well documented against Leishmania donovani and Leishmania amazonensis but unexplored against Leishmania tropica. Structure of the compound was elucidated by FT-IR, mass spectrometry and multinuclear (1H and 13C) magnetic resonance spectroscopy. The compound was evaluated for its anti-leishmanial potentials against L. tropica KWH23 using in vitro anti-promastigote, DNA interaction, apoptosis, docking studies against leishmanolysin (GP63) and trypanothione reductase (TR) receptors using MOE 2016 software. β-sitosterol exhibited significant activity against leishmania promastigotes with IC50 values of 9.2 ± 0.06 μg/mL. The standard drug glucantaime showed IC50 of 5.33 ± 0.07 µg/mL. Further mechanistic studies including DNA targeting and apoptosis induction via acridine orange assay exhibited promising anti-leishmanial potentials for β-sitosterol. Molecular docking with leishmanolysin (GP63) and trypanothione reductase (TR) receptors displayed the binding scores of β-sitosterol with targets TR and GP63 were -7.659 and -6.966 respectively. The low binding energies -61.54 (for TR) and -33.24 (for GP63) indicate that it strongly bind to the active sites of target receptors. The results confirmed that β-sitosterol have considerable anti-leishmanial potentials and need further studies as potential natural anti-leishmanial agent against L. tropica.
    Matched MeSH terms: Antiprotozoal Agents/chemistry; Sitosterols/chemistry; Asteraceae/chemistry*
  4. β Mangostin suppress LPS-induced inflammatory response in RAW 264.7 macrophages in vitro and carrageenan-induced peritonitis in vivo
    Syam S, Bustamam A, Abdullah R, Sukari MA, Hashim NM, Mohan S, et al.
    J Ethnopharmacol, 2014 Apr 28;153(2):435-45.
    PMID: 24607509 DOI: 10.1016/j.jep.2014.02.051
    The fruit hull of Garcinia mangostana Linn. has been used in traditional medicine for treatment of various inflammatory diseases. Hence, this study aims to investigate the in vitro and in vivo anti-inflammatory effect of β mangostin (βM), a major compound present in Garcinia mangostana.
    Matched MeSH terms: Xanthones/chemistry
  5. α1-Acid Glycoprotein Has the Potential to Serve as a Biomimetic Drug Delivery Carrier for Anticancer Agents
    Matsusaka K, Ishima Y, Maeda H, Kinoshita R, Ichimizu S, Taguchi K, et al.
    J Pharm Sci, 2019 11;108(11):3592-3598.
    PMID: 31288036 DOI: 10.1016/j.xphs.2019.07.002
    Nanosize plasma proteins could be used as a biomimetic drug delivery system (DDS) for cancer treatment when loaded with anticancer drugs based on the fact that plasma proteins can serve as a source of nutrients for cancer cells. This prompted us to investigate the potential of α1-acid glycoprotein (AGP) for this role because it is a nanosize plasma protein and binds a variety of anticancer agents. Pharmacokinetic analyses indicated that AGP is distributed more extensively in tumor tissue than human serum albumin, which was already established as a cancer DDS carrier. AGP is possibly being incorporated into tumor cells via endocytosis pathways. Moreover, a synthetic AGP-derived peptide which possesses a high ability to form an α-helix, as deduced from the primary structure of AGP, was also taken up by the tumor cells. AGP loaded with anticancer agents, such as paclitaxel or nitric oxide, efficiently induced tumor cell death. These results suggest that AGP has the potential to be a novel DDS carrier for anticancer agents.
    Matched MeSH terms: Antineoplastic Agents/chemistry*; Drug Carriers/chemistry*; Orosomucoid/chemistry*; Paclitaxel/chemistry
  6. α-glucosidase inhibitors isolated from Mimosa pudica L
    Tasnuva ST, Qamar UA, Ghafoor K, Sahena F, Jahurul MHA, Rukshana AH, et al.
    Nat Prod Res, 2019 May;33(10):1495-1499.
    PMID: 29281898 DOI: 10.1080/14786419.2017.1419224
    The aim of the study was to isolate digestive enzymes inhibitors from Mimosa pudica through a bioassay-guided fractionation approach. Repeated silica gel and sephadex LH 20 column chromatographies of bioactive fractions afforded stigmasterol, quercetin and avicularin as digestive enzymes inhibitors whose IC50 values as compared to acarbose (351.02 ± 1.46 μg mL-1) were found to be as 91.08 ± 1.54, 75.16 ± 0.92 and 481.7 ± 0.703 μg mL-1, respectively. In conclusion, M. pudica could be a good and safe source of digestive enzymes inhibitors for the management of diabetes in future.
    Matched MeSH terms: Hypoglycemic Agents/chemistry; Plant Extracts/chemistry; Mimosa/chemistry*; Glycoside Hydrolase Inhibitors/chemistry
  7. Fulltext α-Mangostin from Cratoxylum arborescens demonstrates apoptogenesis in MCF-7 with regulation of NF-κB and Hsp70 protein modulation in vitro, and tumor reduction in vivo
    Ibrahim MY, Hashim NM, Mohan S, Abdulla MA, Kamalidehghan B, Ghaderian M, et al.
    Drug Des Devel Ther, 2014;8:1629-47.
    PMID: 25302018 DOI: 10.2147/DDDT.S66105
    Cratoxylum arborescens is an equatorial plant belonging to the family Guttiferae. In the current study, α-Mangostin (AM) was isolated and its cell death mechanism was studied. HCS was undertaken to detect the nuclear condensation, mitochondrial membrane potential, cell permeability, and the release of cytochrome c. An investigation for reactive oxygen species formation was conducted using fluorescent analysis. To determine the mechanism of cell death, human apoptosis proteome profiler assay was conducted. In addition, using immunofluorescence and immunoblotting, the levels of Bcl-2-associated X protein (Bax) and B-cell lymphoma (Bcl)-2 proteins were also tested. Caspaces such as 3/7, 8, and 9 were assessed during treatment. Using HCS and Western blot, the contribution of nuclear factor kappa-B (NF-κB) was investigated. AM had showed a selective cytotoxicity toward the cancer cells with no toxicity toward the normal cells even at 30 μg/mL, thereby indicating that AM has the attributes to induce cell death in tumor cells. The treatment of MCF-7 cells with AM prompted apoptosis with cell death-transducing signals. This regulated the mitochondrial membrane potential by down-regulation of Bcl-2 and up-regulation of Bax, thereby causing the release of cytochrome c from the mitochondria into the cytosol. The liberation of cytochrome c activated caspace-9, which, in turn, activated the downstream executioner caspace-3/7 with the cleaved poly (ADP-ribose) polymerase protein, thereby leading to apoptotic alterations. Increase of caspace 8 had showed the involvement of an extrinsic pathway. This type of apoptosis was suggested to occur through both extrinsic and intrinsic pathways and prevention of translocation of NF-κB from the cytoplasm to the nucleus. Our results revealed AM prompt apoptosis of MCF-7 cells through NF-κB, Bax/Bcl-2 and heat shock protein 70 modulation with the contribution of caspaces. Moreover, ingestion of AM at (30 and 60 mg/kg) significantly reduced tumor size in an animal model of breast cancer. Our results suggest that AM is a potentially useful agent for the treatment of breast cancer.
    Matched MeSH terms: Antineoplastic Agents, Phytogenic/chemistry; Clusiaceae/chemistry; Xanthones/chemistry
  8. Fulltext α-Mangostin Nanoparticles Cytotoxicity and Cell Death Modalities in Breast Cancer Cell Lines
    Herdiana Y, Wathoni N, Shamsuddin S, Muchtaridi M
    Molecules, 2021 Aug 24;26(17).
    PMID: 34500560 DOI: 10.3390/molecules26175119
    α-Mangostin (AMG) is a potent anticancer xanthone that was discovered in mangosteen (Garcinia mangostana Linn.). AMG possesses the highest opportunity for chemopreventive and chemotherapeutic therapy. AMG inhibits every step in the process of carcinogenesis. AMG suppressed multiple breast cancer (BC) cell proliferation and apoptosis by decreasing the creation of cancerous compounds. Accumulating BC abnormalities and their associated molecular signaling pathways promotes novel treatment strategies. Chemotherapy is a commonly used treatment; due to the possibility of unpleasant side effects and multidrug resistance, there has been substantial progress in searching for alternative solutions, including the use of plant-derived natural chemicals. Due to the limitations of conventional cancer therapy, nanotechnology provides hope for effective and efficient cancer diagnosis and treatment. Nanotechnology enables the delivery of nanoparticles and increased solubility of drugs and drug targeting, resulting in increased cytotoxicity and cell death during BC treatment. This review summarizes the progress and development of AMG's cytotoxicity and the mechanism of death BC cells. The combination of natural medicine and nanotechnology into a synergistic capital will provide various benefits. This information will aid in the development of AMG nanoparticle preparations and may open up new avenues for discovering an effective BC treatment.
    Matched MeSH terms: Nanoparticles/chemistry*
  9. Fulltext α-Linolenic acid supplementation in BioXcell® extender can improve the quality of post-cooling and frozen-thawed bovine sperm
    Kaka A, Wahid H, Rosnina Y, Yimer N, Khumran AM, Sarsaifi K, et al.
    Anim. Reprod. Sci., 2015 Feb;153:1-7.
    PMID: 25544152 DOI: 10.1016/j.anireprosci.2014.12.001
    The present study was conducted to determine the effects of supplementing α-linolenic acid (ALA) into BioXcell(®) extender on post-cooling, post-thawed bovine spermatozoa and post thawed fatty acid composition. Twenty-four semen samples were collected from three bulls using an electro-ejaculator. Fresh semen samples were evaluated for general motility using computer assisted semen analyzer (CASA) whereas morphology and viability with eosin-nigrosin stain. Semen samples extended into BioXcell(®) were divided into five groups to which 0, 3, 5, 10 and 15 ng/ml of ALA were added, respectively. The treated samples were incubated at 37°C for 15 min for ALA uptake by sperm cells before being cooled for 2 h at 5°C. After evaluation, the cooled samples were packed into 0.25 ml straws and frozen in liquid nitrogen for 24 h before thawing and evaluation for semen quality. Evaluation of cooled and frozen-thawed semen showed that the percentages of all the sperm parameters improved with 5 ng/ml ALA supplement. ALA was higher in all treated groups than control groups than control group. In conclusion, 5 ng/ml ALA supplemented into BioXcell(®) extender improved the cooled and frozen-thawed quality of bull spermatozoa.
    Matched MeSH terms: Spermatozoa/chemistry
  10. α-Glucosidase inhibitory potential and hemolytic evaluation of newly synthesized 3,4,5-trisubstituted-1,2,4-triazole derivatives
    Nafeesa K, Aziz-Ur-Rehman -, Abbasi MA, Siddiqui SZ, Rasool S, Ali Shah SA, et al.
    Pak J Pharm Sci, 2019 Nov;32(6):2651-2658.
    PMID: 31969298
    A series of 1, 2, 4-triazole derivatives bearing piperidine moiety has been introduced as new anti-diabetic drug candidates with least cytotoxicity. p-Chlorophenylsulfonyl chloride (1) and ethyl nipecotate (2) were the starting reagents that resulted into corresponding 3,4,5-trisubstituted-1,2,4-triazole (6) through a series of steps. A series of electrophiles, 9a-e, were synthesized by reacting 4-bromobutyryl chloride (7) with differently substituted aromatic amines (8a-e) under basic aqueous medium. Target derivatives, 10a-e, were synthesized by the reaction of compound 6 with N-aryl-4-bromobutanamides (9a-e) in an aprotic solvent. Structures of all the derivatives were verified by spectroscopic analysis using IR, 1H-NMR, 13C-NMR and EIMS. Most of the derivatives revealed moderate to good α-glucosidase inhibitory activity with reference to acarbose. The moderate hemolytic potential demonstrated least toxicity.
    Matched MeSH terms: Triazoles/chemistry; Glycoside Hydrolase Inhibitors/chemistry
  11. α-Glucosidase activity of oleanolic acid and its oxidative metabolites: DFT and Docking studies
    Anouar el H, Zakaria NS, Alsalme A, Shah SA
    Mini Rev Med Chem, 2015;15(14):1148-58.
    PMID: 26205959
    A natural pentacyclic triterpenoid oleanolic acid 1 and its biotransformed metabolites 2-3 are potential α-glucosidase inhibitors. To elucidate the inhibitory mechanism of compounds 1, 2 and 3 against α-glucosidase, we calculated (i) their electronic and optical properties using DFT and TD-DFT at the B3LYP/6-31G(d) level in gas and IEF-PCM solvent; and (ii) their binding energies to α-glucosidase via docking study. DFT results showed that the α-glucosidase inhibtion is mainly depend on the polarity parameters of the studied compounds. Docking results revealed that the activity increased with binding energies (i.e. the stability of ligand-receptor complex). The specroscopic data of oleanolic acid 1 and its metabolites 2 and 3 are well predicetd for 13C NMR chemical shifts (R2=99%) and 1H NMR chemical shifts (R2=90%); and for (ii) UV/vis spectra. The assignments and interpretation of NMR chemical shifts and bathochromic shift of λMAX absorption bands are discussed.
    Matched MeSH terms: alpha-Glucosidases/chemistry; Oleanolic Acid/chemistry; Glycoside Hydrolase Inhibitors/chemistry
  12. Fulltext α-Amylase and dipeptidyl peptidase-4 (DPP-4) inhibitory effects of Melicope latifolia bark extracts and identification of bioactive constituents using in vitro and in silico approaches
    Quek A, Kassim NK, Lim PC, Tan DC, Mohammad Latif MA, Ismail A, et al.
    Pharm Biol, 2021 Dec;59(1):964-973.
    PMID: 34347568 DOI: 10.1080/13880209.2021.1948065
    CONTEXT: Melicope latifolia (DC.) T. G. Hartley (Rutaceae) was reported to contain various phytochemicals including coumarins, flavonoids, and acetophenones.

    OBJECTIVE: This study investigates the antidiabetic and antioxidant effects of M. latifolia bark extracts, fractions, and isolated constituents.

    MATERIALS AND METHODS: Melicope latifolia extracts (hexane, chloroform, and methanol), fractions, and isolated constituents with varying concentrations (0.078-10 mg/mL) were subjected to in vitro α-amylase and dipeptidyl peptidase-4 (DPP-4) inhibitory assay. Molecular docking was performed to study the binding mechanism of active compounds towards α-amylase and DPP-4 enzymes. The antioxidant activity of M. latifolia fractions and compounds were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and β-carotene bleaching assays.

    RESULTS: Melicope latifolia chloroform extract showed the highest antidiabetic activity (α-amylase IC50: 1464.32 μg/mL; DPP-4 IC50: 221.58 μg/mL). Fractionation of chloroform extract yielded four major fractions (CF1-CF4) whereby CF3 showed the highest antidiabetic activity (α-amylase IC50: 397.68 μg/mL; DPP-4 IC50: 37.16 μg/mL) and resulted in β-sitosterol (1), halfordin (2), methyl p-coumarate (3), and protocatechuic acid (4). Isolation of compounds 2-4 from the species and their DPP-4 inhibitory were reported for the first time. Compound 2 showed the highest α-amylase (IC50: 197.53 μM) and β-carotene (88.48%) inhibition, and formed the highest number of molecular interactions with critical amino acid residues of α-amylase. The highest DPP-4 inhibition was exhibited by compound 3 (IC50: 911.44 μM).

    DISCUSSION AND CONCLUSIONS: The in vitro and in silico analyses indicated the potential of M. latifolia as an alternative source of α-amylase and DPP-4 inhibitors. Further pharmacological studies on the compounds are recommended.

    Matched MeSH terms: alpha-Amylases/chemistry; Antioxidants/chemistry; Hypoglycemic Agents/chemistry; Plant Extracts/chemistry*; Plant Bark/chemistry; Rutaceae/chemistry*; Dipeptidyl-Peptidase IV Inhibitors/chemistry*; Phytochemicals/chemistry
  13. tLyp-1: A peptide suitable to target NRP-1 receptor
    Larue L, Kenzhebayeva B, Al-Thiabat MG, Jouan-Hureaux V, Mohd-Gazzali A, Wahab HA, et al.
    Bioorg Chem, 2023 Jan;130:106200.
    PMID: 36332316 DOI: 10.1016/j.bioorg.2022.106200
    Targeting vascular endothelial growth factor receptor (VEFGR) and its co-receptor neuropilin-1 (NRP-1) is an interesting vascular strategy. tLyp-1 is a tumor-homing and penetrating peptide of 7 amino acids (CGNKRTR). It is a truncated form of Lyp-1 (CGNKRTRGC), which is known to target NRP-1 receptor, with high affinity and specificity. It is mediated by endocytosis via C-end rule (CendR) internalization pathway. The aim of this study is to evaluate the importance of each amino acid in the tLyp-1 sequence through alanine-scanning (Ala-scan) technique, during which each of the amino acid in the sequence was systematically replaced by alanine to produce 7 different analogues. In silico approach through molecular docking and molecular dynamics are employed to understand the interaction between the peptide and its analogues with the NRP-1 receptor, followed by in vitro ligand binding assay study. The C-terminal Arg is crucial in the interaction of tLyp-1 with NRP-1 receptor. Substituting this residue dramatically reduces the affinity of this peptide which is clearly seen in this study. Lys-4 is also important in the interaction, which is confirmed via the in vitro study and the MM-PBSA analysis. The finding in this study supports the CendR, in which the presence of R/K-XX-R/K motif is essential in the binding of a ligand with NRP-1 receptor. This presented work will serve as a guide in the future work pertaining the development of active targeting agent towards NRP-1 receptor.
    Matched MeSH terms: Peptides/chemistry
  14. Fulltext sn-2 Hypothesis: a Review of the Effects of Palm Oil on Blood Lipid Levels
    Sin Teh S, Ong ASH, Choo YM, Mah SH
    J Oleo Sci, 2018;67(6):697-706.
    PMID: 29863090 DOI: 10.5650/jos.ess18009
    Saturated fats are commonly claimed to raise human blood cholesterols and contribute to cardiovascular disease. Previous literature data were highlighted that although palm oil is 50% saturated, it does not behave like a saturated fat. Human trials were conducted to compare the effects on serum cholesterol levels given by palm olein and monounsaturated oils. It was postulated that saturation/unsaturation of the fatty acids situated at sn-2 positions of triglycerides in the fat molecules determine the induced blood lipid levels but not the overall saturation of oils. The results showed that the lipid parameters (LDL and HDL) effects induced by these oils are similar with no significant differences. This study provides concrete evidence that the unsaturation levels of these oils at sn-2 position of TG are similar (90-100%) which are claimed to be responsible for the lipid parameters. In conclusion, the public negative perception on believing that the overall saturation of oils is detrimental to health should be corrected because in fact the unsaturation at sn-2 positions of the saturated vegetable fat such as palm olein and cocoa butter make them behave like mono-unsaturated oils, unlike saturated animal fats that possess a high content of saturated fatty acids at sn-2 position.
    Matched MeSH terms: Triglycerides/chemistry
  15. siRNA Therapy, Challenges and Underlying Perspectives of Dendrimer as Delivery Vector
    Tekade RK, Maheshwari RG, Sharma PA, Tekade M, Chauhan AS
    Curr Pharm Des, 2015;21(31):4614-36.
    PMID: 26486147
    siRNA technology presents a helpful means of gene silencing in mammalian cells. Advancement in the field includes enhanced attentiveness in the characterization of target and off-target effects employing suitable controls and gene expression microarrays. These will permit expansion in the measurement of single and multiple target combinations and also permit comprehensive efforts to understand mammalian cell processes. Another fact is that the delivery of siRNA requires the creation of a nanoparticulate vector with controlled structural geometry and surface modalities inside the targeted cells. On the other hand, dendrimers represent the class of carrier system where massive control over size, shape and physicochemical properties makes this delivery vector exceptional and favorable in genetic transfection applications. The siRNA therapeutics may be incorporated inside the geometry of the density controlled dendrimers with the option of engineering the structure to the specific needs of the genetic material and its indication. The existing reports on the siRNA carrying and deliverance potential of dendrimers clearly suggest the significance of this novel class of polymeric architecture and certainly elevate the futuristic use of this highly branched vector as genetic material delivery system.
    Matched MeSH terms: Polymers/chemistry; Dendrimers/chemistry*
  16. pS2 expression in infiltrating ductal carcinoma of the breast correlates with oestrogen receptor positivity but not with histological grade and lymph node status
    Looi LM, Azura WW, Cheah PL, Ng MH
    Pathology, 2001 Aug;33(3):283-6.
    PMID: 11523925
    This investigation was carried out to gain insight into the prevalence of pS2 expression in invasive ductal breast carcinoma in the Malaysian population and its correlation with oestrogen receptor (ER) protein expression and tumour aggressiveness. Seventy consecutive infiltrating ductal breast carcinomas treated with mastectomy and axillary lymph node clearance were investigated, using the standard avidin-biotin complex immunoperoxidase method with microwave antigen retrieval and commercial monoclonal antibodies (Dako), for expression of pS2 and human ER. This was correlated against histological grade (modified Bloom and Richardson) and the presence of axillary lymph node metastasis of these carcinomas. Four (5.7%) were grade 1, 40 (57.1%) grade 2 and 26 (37.1%) grade 3 tumours. A total of 45 (64%) showed histological evidence of axillary lymph node metastasis. Forty (57%) were ER-positive, while 31 (44%) were pS2-positive. There was a statistically significant correlation between pS2 and ER expressions (chi2-test with Yates correction: P<0.005). There was no correlation between pS2 expression and histological grade (P>0.1) and the presence of lymph node metastasis (P>0.1). Our findings support the views that pS2 may be a co-marker of endocrine responsiveness in invasive breast cancer and that it does not influence breast cancer biology in terms of potential for metastatic spread.
    Matched MeSH terms: Breast Neoplasms/chemistry; Carcinoma, Ductal, Breast/chemistry
  17. Fulltext pH-responsive Virus-like Nanoparticles with Enhanced Tumour-targeting Ligands for Cancer Drug Delivery
    Biabanikhankahdani R, Alitheen NBM, Ho KL, Tan WS
    Sci Rep, 2016 11 24;6:37891.
    PMID: 27883070 DOI: 10.1038/srep37891
    Multifunctional nanocarriers harbouring specific targeting moieties and with pH-responsive properties offer great potential for targeted cancer therapy. Several synthetic drug carriers have been studied extensively as drug delivery systems but not much information is available on the application of virus-like nanoparticles (VLNPs) as multifunctional nanocarriers. Here, we describe the development of pH-responsive VLNPs, based on truncated hepatitis B virus core antigen (tHBcAg), displaying folic acid (FA) for controlled drug delivery. FA was conjugated to a pentadecapeptide containing nanoglue bound on tHBcAg nanoparticles to increase the specificity and efficacy of the drug delivery system. The tHBcAg nanoparticles loaded with doxorubicin (DOX) and polyacrylic acid (PAA) demonstrated a sustained drug release profile in vitro under tumour tissue conditions in a controlled manner and improved the uptake of DOX in colorectal cancer cells, leading to enhanced antitumour effects. This study demonstrated that DOX-PAA can be packaged into VLNPs without any modification of the DOX molecules, preserving the pharmacological activity of the loaded DOX. The nanoglue can easily be used to display a tumour-targeting molecule on the exterior surface of VLNPs and can bypass the laborious and time-consuming genetic engineering approaches.
    Matched MeSH terms: Acrylic Resins/chemistry; Folic Acid/chemistry; Hepatitis B Core Antigens/chemistry*; Nanoparticles/chemistry*
  18. pH-responsive CAP-co-poly(methacrylic acid)-based hydrogel as an efficient platform for controlled gastrointestinal delivery: fabrication, characterization, in vitro and in vivo toxicity evaluation
    Shah SA, Sohail M, Minhas MU, Nisar-Ur-Rehman, Khan S, Hussain Z, et al.
    Drug Deliv Transl Res, 2019 Apr;9(2):555-577.
    PMID: 29450805 DOI: 10.1007/s13346-018-0486-8
    Cellulose acetate phthalate-based pH-responsive hydrogel was synthesized for fabrication of polymeric matrix tablets for gastro-protective delivery of loxoprofen sodium. Cellulose acetate phthalate (CAP) was cross-linked with methacrylic acid (MAA) using free radical polymerization technique. Fourier transform infrared (FTIR) spectra confirmed the formation of cross-linked structure of CAP-co-poly(methacrylic acid). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) confirmed the thermal stability of polymeric networks, and scanning electron microscopy (SEM) and energy-dispersive X-ray spectrum (EDS) images unveiled that the prepared formulations were porous in nature and thus the developed formulations had shown better diffusibility. Swelling and in vitro drug release was performed at various pHs and maximum swelling and release was obtained at pH 7.4, while swelling and release rate was very low at pH 1.2 which confirmed the pH-responsive behavior of CAP-co-poly(MAA). CAP-co-poly(MAA) copolymer prevents the release of loxoprofen sodium into the stomach due to reduced swelling at gastric pH while showing significant swelling and drug release in the colon. Cytotoxicity studies revealed higher biocompatibility of fabricated hydrogel. Acute oral toxicity studies were performed for the evaluation and preliminary screening of safety profile of the developed hydrogels. Matrix tablets were evaluated for release behavior at simulated body pH. The investigations performed for analysis of hydrogels and fabricated matrix tablets indicated the controlled drug release and gastro-protective drug delivery of CAP-co-poly(MAA) hydrogels and pH-sensitive matrix tablets for targeted delivery of gastro-sensitive/irritative agents. Graphical abstract.
    Matched MeSH terms: Cellulose/chemistry; Delayed-Action Preparations/chemistry
  19. Fulltext pH responsive N-succinyl chitosan/Poly (acrylamide-co-acrylic acid) hydrogels and in vitro release of 5-fluorouracil
    Bashir S, Teo YY, Naeem S, Ramesh S, Ramesh K
    PLoS One, 2017;12(7):e0179250.
    PMID: 28678803 DOI: 10.1371/journal.pone.0179250
    There has been significant progress in the last few decades in addressing the biomedical applications of polymer hydrogels. Particularly, stimuli responsive hydrogels have been inspected as elegant drug delivery systems capable to deliver at the appropriate site of action within the specific time. The present work describes the synthesis of pH responsive semi-interpenetrating network (semi-IPN) hydrogels of N-succinyl-chitosan (NSC) via Schiff base mechanism using glutaraldehyde as a crosslinking agent and Poly (acrylamide-co-acrylic acid)(Poly (AAm-co-AA)) was embedded within the N-succinyl chitosan network. The physico-chemical interactions were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and field emission scanning electron microscope (FESEM). The synthesized hydrogels constitute porous structure. The swelling ability was analyzed in physiological mediums of pH 7.4 and pH 1.2 at 37°C. Swelling properties of formulations with various amounts of NSC/ Poly (AAm-co-AA) and crosslinking agent at pH 7.4 and pH 1.2 were investigated. Hydrogels showed higher swelling ratios at pH 7.4 while lower at pH 1.2. Swelling kinetics and diffusion parameters were also determined. Drug loading, encapsulation efficiency, and in vitro release of 5-fluorouracil (5-FU) from the synthesized hydrogels were observed. In vitro release profile revealed the significant influence of pH, amount of NSC, Poly (AAm-co-AA), and crosslinking agent on the release of 5-FU. Accordingly, rapid and large release of drug was observed at pH 7.4 than at pH 1.2. The maximum encapsulation efficiency and release of 5-FU from SP2 were found to be 72.45% and 85.99%, respectively. Kinetics of drug release suggested controlled release mechanism of 5-FU is according to trend of non-Fickian. From the above results, it can be concluded that the synthesized hydrogels have capability to adapt their potential exploitation as targeted oral drug delivery carriers.
    Matched MeSH terms: Acrylamides/chemistry*; Chemistry, Pharmaceutical/methods; Fluorouracil/chemistry; Immunosuppressive Agents/chemistry; Hydrogels/chemistry*; Chitosan/chemistry*
  20. Fulltext pH dominates variation in tropical soil archaeal diversity and community structure
    Tripathi BM, Kim M, Lai-Hoe A, Shukor NA, Rahim RA, Go R, et al.
    FEMS Microbiol Ecol, 2013 Nov;86(2):303-11.
    PMID: 23773164 DOI: 10.1111/1574-6941.12163
    Little is known of the factors influencing soil archaeal community diversity and composition in the tropics. We sampled soils across a range of forest and nonforest environments in the equatorial tropics of Malaysia, covering a wide range of pH values. DNA was PCR-amplified for the V1-V3 region of the 16S rRNA gene, and 454-pyrosequenced. Soil pH was the best predictor of diversity and community composition of Archaea, being a stronger predictor than land use. Archaeal OTU richness was highest in the most acidic soils. Overall archaeal abundance in tropical soils (determined by qPCR) also decreased at higher pH. This contrasts with the opposite trend previously found in temperate soils. Thaumarcheota group 1.1b was more abundant in alkaline soils, whereas group 1.1c was only detected in acidic soils. These results parallel those found in previous studies in cooler climates, emphasizing niche conservatism among broad archaeal groups. Among the most abundant operational taxonomic units (OTUs), there was clear evidence of niche partitioning by pH. No individual OTU occurred across the entire range of pH values. Overall, the results of this study show that pH plays a major role in structuring tropical soil archaeal communities.
    Matched MeSH terms: Soil/chemistry
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