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1.
Exp Cell Res ; 433(2): 113830, 2023 12 15.
Article in English | MEDLINE | ID: mdl-37913974

ABSTRACT

Many cancer cells exhibit enhanced glycolysis, which is seen as one of the hallmark metabolic alterations, known as Warburg effect. Substantial evidence shows that upregulated glycolytic enzymes are often linked to malignant growth. Using glycolytic inhibitors for anticancer treatment has become appealing in recent years for therapeutic intervention in cancers with highly glycolytic characteristic, including non-small cell lung cancer (NSCLC). In this work, we studied the anticancer effects and the underlying mechanisms of combination of benzerazide hydrocholoride (Benz), a hexokinase 2 (HK2) inhibitor and 64, a pyruvate dehydrogenase kinase 1 (PDK1) inhibitor, in several NSCLC cell lines. We found that combination of Benz and 64 exhibited strong synergistic anticancer effects in NCI-H1975, HCC827, NCI-H1299 and SK-LU-1 cell lines. With this combination treatment, we observed changes of certain mechanistic determinants associated with metabolic stress caused by glycolysis restriction, such as mitochondrial membrane potential depolarization, overproduction of reactive oxygen species [1], activation of AMPK and down-regulation of mTOR, which contributed to enhanced apoptosis. Moreover, Benz and 64 together significantly suppressed the tumor growth in HCC827 cell mouse xenograft model. Taken together, our study may suggest that combined inhibition of HK2 and PDK1 using Benz and 64 could be a viable anticancer strategy for NSCLC.


Subject(s)
Carcinoma, Non-Small-Cell Lung , Hexokinase , Lung Neoplasms , Pyruvate Dehydrogenase Acetyl-Transferring Kinase , Animals , Humans , Mice , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/pathology , Cell Line, Tumor , Cell Proliferation , Glycolysis , Hexokinase/antagonists & inhibitors , Lung Neoplasms/drug therapy , Lung Neoplasms/pathology , Pyruvate Dehydrogenase Acetyl-Transferring Kinase/antagonists & inhibitors , Signal Transduction
2.
Bioorg Chem ; 147: 107421, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38714118

ABSTRACT

Targeting the homeostasis of anions and iron has emerged as a promising therapeutic approach for the treatment of cancers. However, single-targeted agents often fall short of achieving optimal treatment efficacy. Herein we designed and synthesized a series of novel dual-functional squaramide-hydroxamic acid conjugates that are capable of synergistically modulating the homeostasis of anions and iron. Among them, compound 16 exhibited the most potent antiproliferative activity against a panel of selected cancer cell lines, and strong in vivo anti-tumor efficacy. This compound effectively elevated lysosomal pH through anion transport, and reduced the levels of intracellular iron. Compound 16 could disturb autophagy in A549 cells and trigger robust apoptosis. This compound caused cell cycle arrest at the G1/S phase, altered the mitochondrial function and elevated ROS levels. The present findings clearly demonstrated that synergistic modulation of anion and iron homeostasis has high potentials in the development of promising chemotherapeutic agents with dual action against cancers.


Subject(s)
Antineoplastic Agents , Apoptosis , Cell Proliferation , Drug Design , Drug Screening Assays, Antitumor , Homeostasis , Hydroxamic Acids , Iron , Humans , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Iron/metabolism , Iron/chemistry , Cell Proliferation/drug effects , Homeostasis/drug effects , Structure-Activity Relationship , Hydroxamic Acids/pharmacology , Hydroxamic Acids/chemistry , Hydroxamic Acids/chemical synthesis , Molecular Structure , Apoptosis/drug effects , Anions/chemistry , Anions/pharmacology , Dose-Response Relationship, Drug , Animals , Cell Line, Tumor , Mice , Quinine/analogs & derivatives
3.
Molecules ; 29(6)2024 Mar 18.
Article in English | MEDLINE | ID: mdl-38542983

ABSTRACT

The polysaccharides from Stemona tuberosa Lour, a kind of plant used in Chinese herbal medicine, have various pharmacological activities, such as anti-inflammatory and antioxidant properties. However, the effects of the extraction methods and the activity of polysaccharides from different parts are still unknown. Therefore, this study aimed to evaluate the effects of different extraction methods on the yields, chemical compositions, and bioactivity of polysaccharides extracted from different parts of Stemona tuberosa Lour. Six polysaccharides were extracted from the leaves, roots, and stems of Stemona tuberosa Lour through the use of hot water (i.e., SPS-L1, SPS-R1, and SPS-S1) and an ultrasound-assisted method (i.e., SPS-L2, SPS-R2, and SPS-S2). The results showed that the physicochemical properties, structural properties, and biological activity of the polysaccharides varied with the extraction methods and parts. SPS-R1 and SPS-R2 had higher extraction yields and total sugar contents than those of the other SPSs (SPS-L1, SPS-L2, SPS-S1, and SPS-S2). SPS-L1 had favorable antioxidant activity and the ability to downregulate MUC5AC expression. An investigation of the anti-inflammatory properties showed that SPS-R1 and SPS-R2 had greater anti-inflammatory activities, while SPS-R2 demonstrated the strongest anti-inflammatory potential. The results of this study indicated that SPS-L1 and SPS-L2, which were extracted from non-medicinal parts, may serve as potent natural antioxidants, but further study is necessary to explore their potential applications in the treatment of diseases. The positive anti-inflammatory effects of SPS-R1 and SPS-R2 in the roots may be further exploited in drugs for the treatment of inflammation.


Subject(s)
Stemonaceae , Stemonaceae/chemistry , Stemonaceae/metabolism , Antioxidants/pharmacology , Antioxidants/metabolism , Polysaccharides/pharmacology , Polysaccharides/metabolism , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/metabolism
4.
Mol Pharm ; 20(8): 4120-4128, 2023 08 07.
Article in English | MEDLINE | ID: mdl-37487027

ABSTRACT

As an important cancer-associated fibroblast-specific biomarker, fibroblast activation protein (FAP) has become an attractive target for tumor diagnosis and treatment. However, most FAP-based radiotracers showed inadequate uptake and short retention in tumors. In this study, we designed and synthesized a novel FAP ligand (DOTA-GPFAPI-04) through assembling three functional moieties: a quinoline-based FAP inhibitor for specifically targeting FAP, a FAP substrate Gly-Pro as a linker for increasing the FAP protein interaction, and a 2,2',2″,2‴-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA) chelator for radiolabeling with different radionuclides. The FAP targeting ability of DOTA-GPFAPI-04 was investigated by molecular docking studies. DOTA-GPFAPI-04 was then radiolabeled with 68Ga to give [68Ga]Ga-DOTA-GPFAPI-04 for positron emission tomography (PET) imaging of glioblastoma. [68Ga]Ga-DOTA-GPFAPI-04 exhibited a purity of >98% and high stability analyzed by radio-HPLC in saline and mouse serum. Cell uptake studies demonstrated the targeting specificity of the probe. Further in vivo pharmacokinetic studies in normal mice demonstrated the quick clearance of the probe. Moreover, compared with the widely studied [68Ga]Ga-FAPI-04, [68Ga]Ga-DOTA-GPFAPI-04 showed much higher U87MG tumor uptake values (4.467 ± 0.379 for [68Ga]Ga-DOTA-GPFAPI-04 and 1.267 ± 0.208% ID/g for [68Ga]Ga-FAPI-04 at 0.5 h post-injection, respectively). The area under the curve based on time-activity curve (TAC) analysis for tumor radioactivity in small animal models was 422.5 for [68Ga]Ga-DOTA-GPFAPI-04 and 98.14 for [68Ga]Ga-FAPI-04, respectively, demonstrating that the former had longer tumor retention time. The tumor-to-muscle (T/M) ratio for [68Ga]Ga-DOTA-GPFAPI-04 reached 9.15 in a U87MG xenograft animal model. PET imaging and blocking assays showed that [68Ga]Ga-DOTA-GPFAPI-04 had specific tumor uptake. In summary, this study demonstrates the successful synthesis and evaluation of a novel FAPI targeting probe, [68Ga]Ga-DOTA-GPFAPI-04, with a Gly-Pro sequence. It shows favorable in vivo glioblastoma imaging properties and relatively long tumor retention, highlighting DOTA-GPFAPI-04 as a promising molecular scaffold for developing FAP targeting tumor theranostic agents.


Subject(s)
Glioblastoma , Humans , Mice , Animals , Glioblastoma/diagnostic imaging , Glioblastoma/metabolism , Gallium Radioisotopes , Molecular Docking Simulation , Positron-Emission Tomography/methods , Fibroblasts/metabolism , Positron Emission Tomography Computed Tomography
5.
Org Biomol Chem ; 21(28): 5732-5736, 2023 Jul 19.
Article in English | MEDLINE | ID: mdl-37382385

ABSTRACT

In this paper, we describe the synthesis and properties of a Golgi-targeting fluorescent probe for the selective detection of chloride anions. Specifically, we have synthesized one quaternized quinoline derivative bearing a sulfanilamido group and found that this compound is able to primarily target the Golgi apparatus and detect the changes in the concentration of cellular chloride anions.

6.
Org Biomol Chem ; 22(1): 90-94, 2023 Dec 20.
Article in English | MEDLINE | ID: mdl-38047717

ABSTRACT

Indole-3-carbinol, bisindolylmethanes (BIMs) and indole-3-methanamines exhibit diverse therapeutic activities. Fluorinated molecules are widely used in pharmaceuticals. Herein we report a facile and straightforward method for the successful synthesis of difluoromethylated indole-3-carbinols, bisindolylmethanes and indole-3-methanamines by a Friedel-Crafts reaction. The reaction involves the in situ generation of difluoroacetaldehyde from difluoroacetaldehyde ethyl hemiacetal in the presence of a base or an acid. This protocol is distinguished by its good to excellent yields, broad substrate compatibility, good functional group tolerance and scalability.

7.
Phytother Res ; 37(12): 5837-5853, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37621136

ABSTRACT

Upon prolonged use of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in non-small-cell lung cancer (NSCLC), acquired drug resistance inevitably occurs. This study investigates the combined use of EGFR-TKIs (gefitinib or osimertinib) with epigallocatechin gallate (EGCG) to overcome acquired drug resistance in NSCLC models. The in vitro antiproliferative effects of EGFR-TKIs and EGCG combination in EGFR-mutant parental and resistant cell lines were evaluated. The in vivo efficacy of the combination was assessed in xenograft mouse models derived from EGFR-TKI-resistant NSCLC cells. We found that the combined use of EGFR-TKIs and EGCG significantly reversed the Warburg effect by suppressing glycolysis while boosting mitochondrial respiration, which was accompanied by increased cellular ROS and decreased lactate secretion. The combination effectively activated the AMPK pathway while inhibited both ERK/MAPK and AKT/mTOR pathways, leading to cell cycle arrest and apoptosis, particularly in drug-resistant NSCLC cells. The in vivo results obtained from mouse tumor xenograft model confirmed that EGCG effectively overcame osimertinib resistance. This study revealed that EGCG suppressed cancer bypass survival signaling and altered cancer metabolic profiles, which is a promising anticancer adjuvant of EGFR-TKIs to overcome acquired drug resistance in NSCLC.


Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Humans , Animals , Mice , Carcinoma, Non-Small-Cell Lung/pathology , Proto-Oncogene Proteins c-akt/metabolism , AMP-Activated Protein Kinases , Lung Neoplasms/pathology , Cell Proliferation , Protein Kinase Inhibitors/pharmacology , Drug Resistance, Neoplasm , ErbB Receptors , Glucose/pharmacology , Cell Line, Tumor , Mutation
8.
Molecules ; 28(3)2023 Jan 30.
Article in English | MEDLINE | ID: mdl-36770971

ABSTRACT

Cellular mesenchymal-epithelial transition factor (c-Met), an oncogenic transmembrane receptor tyrosine kinase (RTK), plays an essential role in cell proliferation during embryo development and liver regeneration. Thioredoxin reductase (TrxR) is overexpressed and constitutively active in most tumors closely related to cancer recurrence. Multi-target-directed ligands (MTDLs) strategy provides a logical approach to drug combinations and would adequately address the pathological complexity of cancer. In this work, we designed and synthesized a series of selenium-containing tepotinib derivatives by means of selenium-based bioisosteric modifications and evaluated their antiproliferative activity. Most of these selenium-containing hybrids exhibited potent dual inhibitory activity toward c-Met and TrxR. Among them, compound 8b was the most active, with an IC50 value of 10 nM against MHCC97H cells. Studies on the mechanism of action revealed that compound 8b triggered cell cycle arrest at the G1 phase and caused ROS accumulations by targeting TrxR, and these effects eventually led to cell apoptosis. These findings strongly suggest that compound 8b serves as a dual inhibitor of c-Met and TrxR, warranting further exploitation for cancer therapy.


Subject(s)
Antineoplastic Agents , Selenium , Antineoplastic Agents/pharmacology , Thioredoxin-Disulfide Reductase/metabolism , Selenium/pharmacology , Piperidines/pharmacology , Cell Proliferation , Drug Screening Assays, Antitumor
9.
Bioorg Med Chem Lett ; 30(19): 127461, 2020 10 01.
Article in English | MEDLINE | ID: mdl-32755679

ABSTRACT

Two lysosome-targeting fluorescent anion transporters derived from coumarins, trifluoromethylated arylsquaramides and morpholines were synthesized, and their specificity and efficiency to target and alkalize lysosomes were investigated. They are able to target lysosomes specifically. Compared with the previous analogue without trifluoromethyl substituents, these two conjugates, in particular the one having a 3,5-bis(trifluoromethyl) substituent, exhibit significantly higher ability to facilitate the transport of chloride anions, alkalize lysosomes and reduce the activity of lysosomal Cathepsin B enzyme. The present finding suggests that improving the anionophoric activity of lysosome-targeting fluorescent anion transporters is favorable to the efficiency to alkalize lysosomes and deactivate lysosomal Cathepsin B enzyme.


Subject(s)
Cathepsin B/antagonists & inhibitors , Coumarins/pharmacology , Cyclobutanes/pharmacology , Ion Transport/drug effects , Lysosomes/drug effects , Chlorides/metabolism , Coumarins/chemical synthesis , Cyclobutanes/chemical synthesis , HeLa Cells , Humans , Hydrogen-Ion Concentration , Morpholines/chemical synthesis , Morpholines/pharmacology
10.
Environ Res ; 191: 110176, 2020 12.
Article in English | MEDLINE | ID: mdl-32950515

ABSTRACT

To minimize waste production and reduce reliance on fossil fuels, agricultural waste such as rice straw has been actively used in biochemical production. In Taiwan, cellulosic waste has been used in anaerobic digestion for bioethanol production. This process produces a large amount of biomass-associated sludge that may become a serious environmental issue. Therefore, in this study, the anaerobic digestion sludge was recycled for the production of activated carbon via pyrolysis and activation by KOH. Surface characterization showed increased surface area and development of microporous structure upon activation. The FTIR image showed that high temperature activation eliminated most functional groups in the activated carbon, except for CO and C-O groups. The results showed that the activated carbon could be used for pollutant adsorbents such as molecular dyes (methylene blue: 217 mg g-1) and metal ions (copper: 169 mg g-1) from aqueous solution. In addition, the as-synthesized activated carbon can be used for CO2 capture and capacitor. Instead of focusing on one single application, we proposed that centralized production of activated carbon could be used in various applications, while further modification could be adopted depending on the need of its specific application.


Subject(s)
Charcoal , Sewage , Biomass , Recycling , Taiwan
11.
BMC Anesthesiol ; 20(1): 265, 2020 10 21.
Article in English | MEDLINE | ID: mdl-33087063

ABSTRACT

BACKGROUND: The prognosis of hospitalized patients after emergent endotracheal intubation (ETI) remains poor. Our aim was to evaluate the 30-d hospitalization mortality of subjects undergoing ETI during daytime or off-hours and to analyze the possible risk factors affecting mortality. METHODS: A single-center retrospective study was performed at a university teaching facility from January 2015 to December 2018. All adult inpatients who received ETI in the general ward were included. Information on patient demographics, vital signs, ICU (Intensive care unit) admission, intubation time (daytime or off-hours), the department in which ETI was performed (surgical ward or medical ward), intubation reasons, and 30-d hospitalization mortality after ETI were obtained from a database. RESULTS: Over a four-year period, 558 subjects were analyzed. There were more male than female in both groups (115 [70.1%] vs 275 [69.8%]; P = 0.939). A total of 394 (70.6%) patients received ETI during off-hours. The patients who received ETI during the daytime were older than those who received ETI during off-hours (64.95 ± 17.54 vs 61.55 ± 17.49; P = 0.037). The BMI of patients who received ETI during the daytime was also higher than that of patients who received ETI during off-hours (23.08 ± 3.38 vs 21.97 ± 3.25; P < 0.001). The 30-d mortality after ETI was 66.8% (373), which included 68.0% (268) during off-hours and 64.0% (105) during the daytime (P = 0.361). Multivariate Cox regression analysis found that the significant factors for the risk of death within 30 days included ICU admission (HR 0.312, 0.176-0.554) and the department in which ETI was performed (HR 0.401, 0.247-0.653). CONCLUSIONS: The 30-d hospitalization mortality after ETI was 66.8%, and off-hours presentation was not significantly associated with mortality. ICU admission and ETI performed in the surgical ward were significant factors for decreasing the risk of death within 30 days. TRIAL REGISTRATION: This trial was retrospectively registered with the registration number of ChiCTR2000038549 .


Subject(s)
After-Hours Care , Emergency Medical Services , Hospital Mortality , Intubation, Intratracheal/mortality , Adult , Aged , Aged, 80 and over , Female , Hospitalization , Humans , Male , Middle Aged , Proportional Hazards Models , Retrospective Studies , Risk Factors , Young Adult
12.
Drug Dev Res ; 81(2): 242-255, 2020 04.
Article in English | MEDLINE | ID: mdl-31837041

ABSTRACT

With the surge in the cases of Alzheimer's disease (AD) over the years, several targets have been explored to curb the disease. Cholinesterases, namely acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), remain to be the available targets that are amendable to currently approved treatments. In this study, a series of novel compounds based on tramiprosate, a highly specific amyloid beta (Aß) inhibitor, was designed to inhibit AChE, BuChE, and Aß aggregation. In particular, the addition of a pyridinium/isoquinolinium ring to the tramiprosate moiety (to give compounds 3a-j) led to an increase in the binding affinity for the catalytic active site of cholinesterase, which was hampered by the presence of sulfonic acid. Exclusion of the sulfonic acid moiety led to a novel but effective class of cholinesterase inhibitors (9a-w). in vitro Aß aggregation inhibition assay indicated that compounds 3a-j, 9e-f, 9i-l, 9q, 9r, 9u-w, and 12 could inhibit over 10% Aß aggregation at 1 mM concentration. Cholinesterase inhibition assay suggested that compounds 9g, 9h, 9o, and 9q-t exhibit over 70% inhibition on both AChE and BuChE at a concentration of 100 µM. Amongst the designed molecules, compound 9r (ca 18% at 1 mM) showed comparable inhibitory effect on the inhibition of Aß aggregation with tramiprosate (ca 20% at 1 mM), along with impressive cholinesterase inhibitory potential (AChE IC50 = 13 µM and BuChE IC50 = 12 µM), acceptable toxicity and ability to pass through blood brain barrier, which could be used to ameliorate the phenotypes of AD in preclinical models.


Subject(s)
Acetylcholinesterase/metabolism , Alzheimer Disease/drug therapy , Amyloid beta-Peptides/antagonists & inhibitors , Cholinesterase Inhibitors/chemical synthesis , Pyridinium Compounds/chemical synthesis , Taurine/analogs & derivatives , Acetylcholinesterase/chemistry , Alzheimer Disease/genetics , Amyloid beta-Peptides/chemistry , Animals , Catalytic Domain , Cell Line , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/pharmacology , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Design , Humans , Male , Mice , Mice, Transgenic , Molecular Docking Simulation , Molecular Structure , Pyridinium Compounds/chemistry , Pyridinium Compounds/pharmacology , Structure-Activity Relationship , Taurine/chemistry
13.
Org Biomol Chem ; 17(6): 1558-1571, 2019 02 06.
Article in English | MEDLINE | ID: mdl-30694281

ABSTRACT

Anion transporters have attracted substantial interest due to their ability to induce cell apoptosis by disrupting cellular anion homeostasis. In this paper we describe the synthesis, anion recognition, transmembrane anion transport and cell apoptosis-inducing activity of a series of fluorinated 1,3-bis(benzimidazol-2-yl)benzene derivatives. These compounds were synthesized from the condensation of 1,3-benzenedialdehyde or 5-fluoro-1,3-benzenedialdehyde with the corresponding 1,2-benzenediamines and fully characterized. They are able to form stable complexes with chloride anions, and exhibit potent liposomal and in vitro anionophoric activity. Their anion transport efficiency may be ameliorated by the total number of fluorine atoms, and the enhanced anionophoric activity was a likely consequence of the increased lipophilicity induced by fluorination. Most of these fluorinated bisbenzimidazoles exhibit potent cytotoxicity toward the selected cancer cells. Mechanistic investigations suggest that these compounds are able to trigger cell apoptosis probably by disrupting the homeostasis of chloride anions.


Subject(s)
Apoptosis/drug effects , Bisbenzimidazole/chemistry , Bisbenzimidazole/pharmacology , Chlorides/chemistry , Drug Design , Halogenation , Cell Line, Tumor , Humans , Hydrogen Bonding , Hydrophobic and Hydrophilic Interactions , Structure-Activity Relationship
14.
Med Sci Monit ; 25: 1769-1779, 2019 Mar 08.
Article in English | MEDLINE | ID: mdl-30848248

ABSTRACT

BACKGROUND Cardiac remote ischemic conditioning (RIC) is a noninvasive cardioprotective method in ischemia-reperfusion injury and acute myocardial infarction (AMI). The aims of this study were to investigate the effects of RIC in a rat model of AMI. MATERIAL AND METHODS Adult male Sprague-Dawley rats included the AMI group that underwent ligation of the left anterior descending (LAD) coronary artery (n=24), the RIC group that consisted the AMI rat model treated with RIC once daily in the left hind limb until days 1, 7 and 14 (n=24), and the sham group (n=24). Myocardial infarct size was measured by routine histology with triphenyltetrazolium chloride (TTC) and Masson's trichrome histochemical staining for myocardial necrosis and fibrosis, respectively. Serum levels of Bcl-2, Bax, caspase-3, and inducible nitric oxide synthase (iNOS) were measured by enzyme-linked immunosorbent assay (ELISA). The apoptosis index was detected using the TUNEL assay. Spectrophotometry of the myocardium was used to identify mitochondrial complexes and myocardial ATP. RESULTS The RIC group showed improved cardiac hemodynamics, reduced the size of the myocardial infarction, upregulated expression of Bcl-2, and down-regulation of the levels of Bax, caspase-3, and iNOS, and reduced cardiac myocyte apoptosis and inhibited the opening of the mitochondrial permeability transition pore (MPTP). CONCLUSIONS In a rat model of AMI, RIC improved the hemodynamic index, reduce the levels of apoptosis and myocardial injury, and improved mitochondrial function.


Subject(s)
Ischemic Preconditioning/methods , Myocardial Infarction/metabolism , Reperfusion Injury/prevention & control , Animals , Apoptosis , Cardiotonic Agents , Caspase 3/analysis , Caspase 3/blood , Disease Models, Animal , Heart Injuries/prevention & control , Hemodynamics , Male , Mitochondria/metabolism , Myocardial Infarction/physiopathology , Myocardial Reperfusion Injury/metabolism , Myocardium/metabolism , Myocardium/pathology , Proto-Oncogene Proteins c-bcl-2/analysis , Proto-Oncogene Proteins c-bcl-2/blood , Rats , Rats, Sprague-Dawley , Reperfusion Injury/therapy , bcl-2-Associated X Protein/analysis , bcl-2-Associated X Protein/blood
15.
Sensors (Basel) ; 19(14)2019 Jul 22.
Article in English | MEDLINE | ID: mdl-31336630

ABSTRACT

This paper presents a detailed experimental assessment of Gaussian Process (GP) regression for air-to-ground communication channel prediction for relay missions in urban environment. Considering restrictions from outdoor urban flight experiments, a way to simulate complex urban environments at an indoor room scale is introduced. Since water significantly absorbs wireless communication signal, water containers are utilized to replace buildings in a real-world city. To evaluate the performance of the GP-based channel prediction approach, several indoor experiments in an artificial urban environment were conducted. The performance of the GP-based and empirical model-based prediction methods for a relay mission was evaluated by measuring and comparing the communication signal strength at the optimal relay position obtained from each method. The GP-based prediction approach shows an advantage over the model-based one as it provides a reasonable performance without a need for a priori information of the environment (e.g., 3D map of the city and communication model parameters) in dynamic urban environments.

16.
Org Biomol Chem ; 16(43): 8025-8029, 2018 11 07.
Article in English | MEDLINE | ID: mdl-30334042

ABSTRACT

In this paper we present the first example of a lysosome-targeting fluorescent ionophore. Specifically, we synthesized a squaramide derivative bearing a coumarin fluorophore and a morpholinyl group, and found that it was able to target and efficiently deacidify lysosomes. In contrast, an analogue without a morpholinyl group exhibits much lower ability to localize in lysosomes and is much less active in regulating the lysosomal pH.

17.
Sensors (Basel) ; 18(7)2018 Jul 03.
Article in English | MEDLINE | ID: mdl-29970818

ABSTRACT

In this paper, a new method for planning coverage paths for fixed-wing Unmanned Aerial Vehicle (UAV) aerial surveys is proposed. Instead of the more generic coverage path planning techniques presented in previous literature, this method specifically concentrates on decreasing flight time of fixed-wing aircraft surveys. This is achieved threefold: by the addition of wind to the survey flight time model, accounting for the fact fixed-wing aircraft are not constrained to flight within the polygon of the region of interest, and an intelligent method for decomposing the region into convex polygons conducive to quick flight times. It is shown that wind can make a huge difference to survey time, and that flying perpendicular can confer a flight time advantage. Small UAVs, which have very slow airspeeds, can very easily be flying in wind, which is 50% of their airspeed. This is why the technique is shown to be so effective, due to the fact that ignoring wind for small, slow, fixed-wing aircraft is a considerable oversight. Comparing this method to previous techniques using a Monte Carlo simulation on randomised polygons shows a significant reduction in flight time.

18.
Biochem Biophys Res Commun ; 488(2): 278-284, 2017 06 24.
Article in English | MEDLINE | ID: mdl-28479248

ABSTRACT

Recent studies have demonstrated that remote ischemic conditioning (RIC) creates cardioprotection against ischemia/reperfusion injury and myocardial infarction (MI); however, the effects of non-invasive remote ischemic conditioning (nRIC) on prognosis and rehabilitation after MI (post-MI) remain unknown. We successfully established MI models involving healthy adult male Sprague-Dawley rats. The nRIC group repeatedly underwent 5 min of ischemia and 5 min of reperfusion in the left hind limb for three cycles every other day until weeks 4, 6, and 8 after MI. nRIC improved cardiac hemodynamic function and mitochondrial respiratory function through increasing myocardial levels of mitochondrial respiratory chain complexes I, II, III, IV, and adenosine triphosphate (ATP) and decreasing the activity of nitric oxide synthase (NOS). nRIC could inhibit cardiomyocytes apoptosis and reduce myocardium injury through raising the expression of Bcl-2 and reduced the content of creatine kinase-MB, cardiac troponin I and Bax. The results indicated that long-term nRIC could accelerate recovery and improve prognosis and rehabilitation in post-MI rats.


Subject(s)
Ischemic Preconditioning, Myocardial , Myocardial Infarction/rehabilitation , Myocardial Infarction/therapy , Animals , Male , Myocardial Infarction/metabolism , Rats , Rats, Sprague-Dawley
19.
J Org Chem ; 82(24): 13368-13375, 2017 12 15.
Article in English | MEDLINE | ID: mdl-29164882

ABSTRACT

In this paper, we present the synthesis, anion recognition, and anionophoric activity of 1,3,5-tris(aminomethyl)-2,4,6-triethylbenzene-based tripodal 3α-hydroxy-7α,12α-diamino-5ß-cholan-24-oate conjugate 1 and the corresponding tris(2-aminoethyl)amine-based analogue 2 and choloyl analogue 3. Their affinity toward anions was evaluated by means of competitive displacement assay using 5-carboxyfluorescein (5-FAM) as a fluorescent indicator. The results indicate compounds 1 and 2 exhibit strong recognition toward a wide range of biologically important anions, in particular, toward sulfate and phosphate anions. In MeOH-HEPES (4/1, pH 7), the binding constants of compounds 1 and 2 are 416- and 168-fold higher for sulfate than for chloride and 35- and 25-fold higher for phosphate than for chloride, respectively. The anion transport activity was measured by use of pH discharge assay and chloride-ion-selective electrode technique. The results indicate that compounds 1 and 2 function as effective anion-selective transporters in the order of ClO4- > I- > NO3- > Br- > Cl- > SO42- > H2PO4- and exhibit anionophoric activity via a process of major anion exchange and minor anion/cation symport. In addition, some insights into the correlation of the anion binding affinity with the transport efficiency are also briefly discussed.

20.
Bioorg Med Chem Lett ; 27(9): 1999-2002, 2017 05 01.
Article in English | MEDLINE | ID: mdl-28325602

ABSTRACT

Two tripodal squaramide conjugates having 4-(trifluoromethyl)phenyl and 3,5-bis(trifluoromethyl)phenyl substituents were synthesized and found to exhibit highly efficient transmembrane anion transport with the EC50 values being 0.14 and 0.75mol%, respectively. Though one of them has been reported to act as a strong anion receptor, in particular for sulfate anions, these two compounds exhibit no significant selectivity with respect to the tested monovalent anions and a very low level of activity in the presence of sulfate anions.


Subject(s)
Anions/metabolism , Ion Transport/drug effects , Quinine/analogs & derivatives , Chlorides/metabolism , Halogenation , Liposomes/metabolism , Methylation , Quinine/chemistry , Quinine/pharmacology , Sulfates/metabolism
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