Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Genet Eng Biotechnol ; 21(1): 131, 2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-37987952

RESUMO

BACKGROUND: Breast cancer is the most significant threat to women worldwide. Most chemotherapeutic drugs cause cancer cell death and apoptosis by inducing oxidative stress and producing reactive oxygen species (ROS). Cancer cells have a higher rate of metabolic activity than normal cells and thus produce more ROS. Glutathione and its related enzymes are the most significant antioxidant defense mechanisms that protect cells from oxidative and chemotherapeutic impacts. The anticancer actions of phenolic compounds were greatly confirmed. Using phenolic compounds as drugs in combination with chemotherapy may improve health, improve treatment outcomes, and reduce dose and damage. The goal of the study was to treat breast cancer cell lines (MCF-7) with Tamarindus indica extract individually and in combination with the anticancer drug tamoxifen (TAM) to improve therapeutic efficacy. RESULTS: After 48 h of incubation at IC25 concentrations of T. indica extract (47.3 g/mL), tamoxifen (0.8 g/mL), and their co-treatments, the biochemical and genotoxic effects on MCF-7 cell lines were investigated. In MCF7 cell lines, T. indica extract increased reduced glutathione levels as well as glutathione transferase, glutathione peroxidase, and glutathione reductase activities. The same was true for oxidative state indicators, where higher levels of catalase and lactate dehydrogenase activity were associated with higher levels of malondialdehyde. T. indica has almost no effect on the DNA damage parameters. All of these variations can produce alterations in cancer cell genotoxicity and apoptotic pathways, explaining the restoration of DNA moment to normal levels and enhanced survival. CONCLUSION: Cytotoxic and genotoxic effect of treatment with T. indica extract could be attributed to the dynamic interaction of glutathione cycle and antioxidant enzymes to combat oxidative stress, which can be considered as a positive therapeutic effect. On the other hand, the negative response of tamoxifen efficacy when co-treated with T. indica reversed tamoxifen's genotoxicity and enhanced survival.

3.
Arch Biochem Biophys ; 736: 109539, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36746259

RESUMO

In this research, Orobanche aegyptiaca extract was utilized as an eco-friendly, and cost-effective green route for the construction of bimetallic silver-selenium nanoparticles (Ag-Se NPs). Bimetallic Ag-Se NPs were characterized by XRD, EDX, FTIR, HR-TEM, DLS, SEM/mapping and EDX studies. Antimicrobial, and antibiofilm potentials were tested against some selected pathogenic bacteria and unicellular fungi by ZOI, MIC, effect of UV exposure, and inhibition %. Reaction mechanism was assessed through membrane leakage assay and SEM imaging. HRTEM analysis confirmed the spherical nature and was ranged from 18.1 nm to 72.0 nm, and the avarage particle size is determined to be 30.58 nm. SEM imaging prove that bimetallic Ag-Se NPs presents as a bright particles, and both Ag and Se were distributed equally across O. aegyptiaca extract and Guar gum stabilizers. ZOI results showed that, bimetallic Ag-Se NPs have antimicrobial activity against S. aureus (20.0 nm), E. coli (18.5 nm), P. aeruginosa (12.6 nm), and C. albicans (18.2 nm). In addition, bimetallic Ag-Se NPs were able to inhibit the biofilm formation for S. aureus by 79.48%, for E. coli by 78.79%, for P. aeruginosa by 77.50%, and for C. albicans by 73.73%. Bimetallic Ag-Se NPs are an excellent disinfectant once it had excited by UV light. It was observed that the quantity of cellular protein discharged from S. aureus is directly proportional to the concentration of bimetallic Ag-Se NPs and found to be 244.21 µg/mL after the treatment with 1 mg/mL, which proves the antibacterial characteristics, and explains the creation of holes in the cell membrane of S. aureus producing in the oozing out of the proteins from the S. aureus cytoplasm. Based on the promising properties, they showed superior antimicrobial potential at low concentration (to avoid toxicity) and continued-phase durability, they may use in pharmaceutical and biomedical applications.


Assuntos
Nanopartículas Metálicas , Orobanche , Selênio , Selênio/farmacologia , Prata/farmacologia , Orobanche/metabolismo , Staphylococcus aureus/metabolismo , Escherichia coli/metabolismo , Raios Ultravioleta , Extratos Vegetais/farmacologia , Extratos Vegetais/metabolismo , Antibacterianos/farmacologia , Antibacterianos/metabolismo , Bactérias , Biofilmes , Testes de Sensibilidade Microbiana
4.
Sci Rep ; 13(1): 942, 2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36653379

RESUMO

Recently, scientist study the role of surfactants for carbon steel corrosion protection. In the present study, newly tetra-cationic surfactant (CS4: 1,N1'-(ethane-1,2-diyl) bis (N1, N2-didodecyl-N2-(2- (((E)-3-hydroxy-4-methoxy-benzylidene)amino)ethyl)ethane-1,2-diaminium) chloride) based on Schiff-base compound(5,5'-((1E,17E)-2,5,8,11,14,17-hexaazaoctadeca-1,17-diene-1,18-diyl)bis(2-methoxyphenol) was synthesised, purified and characterized using FTIR and 1HNMR spectroscopy. The synthesized Tetra-cationic surfactant (CS4) was evaluated as anti-corrosion for carbon steel (CS-metal) in aggressive 1 M HCl using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques (PDP). CS4 compound had a good surface-active property by reducing the surface tension as a result to the hydrophobic chains role. The prepared CS4 behaved as hybrid inhibitor (mixed-type) by blocking the anodic and cathodic sites. CS4 exhibited good inhibition efficiency reached 95.69%. The surface morphology of CS-metal was studied using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS)confirming the anti-corrosive effect of CS4 compound returned into the adsorption process of CS4 molecules over CS-metal which obeyed Langmuir adsorption isotherm. The inhibitive effect of CS4 was supported by theoretical quantum chemical studies using the density functional theory (DFT), Monte Carlo (MC) and Molecular Dynamic (MD) simulation.

5.
J Genet Eng Biotechnol ; 18(1): 74, 2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33215267

RESUMO

BACKGROUND: The multidrug resistance (MDR) of cancer cells is a major obstacle to cancer treatment. Glutathione S-transferase Pi (GSTP1-1) catalyzes the conjugation of glutathione with anticancer drugs and therefore reduces their efficacy. Phenolic compounds have the potential to inhibit GST P1-1 activity, which is a promising goal to overcome MDR and increase the efficacy of chemotherapy. RESULTS: Three fractions (dichloromethane, ethyl acetate, and n-butanol) were prepared from Tamarindus indica seeds to determine their phenolic and flavonoid properties as well as their antioxidant/pro-oxidant properties. The n-butanol fraction displayed the highest levels of phenol ( 378 ± 11.7 mg gallic acid equivalent/g DW) and flavonoids (83 ± 6.0 mg rutin equivalent/g DW). Inhibiting effects on purified GSTP1-1 activity in human erythrocytes (eGST), placenta (pGST), and hGSTP1-1 have been studied. The n-butanol fraction was the most effective in inhibiting eGST, hGSTP1-1, and pGST with IC50 values of 3.0 ± 0.7, 4.85 ± 0.35, and 6.6 ± 1.2 µg/ml, respectively. Cellular toxicity was investigated for the T. indica n-butanol fraction on various human cancerous cell lines. The only ones affected were MCF-7 cell lines (72%) and HePG2 (52%) indicated cytotoxicity. The value of IC50 is 68.5 µg/ml of T. indica n-butanol fraction was observed compared to 1.7 µg/ml tamoxifen in MCF-7 cell lines. The combination of treatment of T. indica extract with the medicinally approved drug tamoxifen had unexpected effects; complete elimination of the cytotoxic inhibition effect of tamoxifen and the plant extract was observed. CONCLUSIONS: However T. indica extract has a cytotoxic effect on the MCF-7 cell line; in certain situations, plant products can have an opposite effect to the intended drug, which decreases the impact of the drug.

6.
Int J Biol Macromol ; 2020 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-32353502

RESUMO

A novel adsorbent based on N-Aminorhodanine modified chitosan hydrogel was synthesized and evaluated for antibacterial and copper ions removal from aqueous systems. N-Aminorhodanine was reacted with glutaraldehyde to yield Schiff base followed by reaction with chitosan to obtain the new hydrogel adsorbent. The new adsorbent was analyzed using FTIR, 1H NMR, XRD, TGA, HR-SEM and EDX in addition to the swelling behavior. The maximum adsorption capacities of chitosan and modified chitosan for copper ions were 38 and 62.5 mg/g respectively. The adsorption isotherm belongs Freundlich model and pseudo second order kinetics regime. The adsorption was reach to maximum within 15 min for modified chitosan hydrogel while take about 360 min for chitosan. Regeneration of adsorbent showed only 23% decline after 6 cycles which indicate the stability of the new adsorbent and it can be reused several times with good efficiency. N-Aminorhodanine modified chitosan hydrogel showed good activity towards gram positive bacteria.

7.
RSC Adv ; 9(19): 10473-10485, 2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-35515280

RESUMO

In this work, we report the synthesis of two Schiff bases of substituted gallic acid derivatives via amidation reaction and their characterization using 1H-NMR spectroscopy to study their inhibition performance on the aggressive attack of HCl on mild steel (MS). The inhibitive performance was examined using chemical (weight loss) and electrochemical (Tafel and EIS) test methods. The results indicate that these derivatives significantly suppress the dissolution rate of mild steel via adsorption phenomena, which correlates to the Langmuir adsorption model. Tafel data display the mixed-type properties of these compounds and EIS results show that increasing Schiff base concentration not only leads to delaying the charge transfer (R ct) of iron from 26.4 ohm cm-2 to 227.7 ohm cm-2 but also decreases the capacitance of the adsorbed double layer (C dl) from 8.58 (F cm-2) × 10-5 to 2.55 (F cm-2) × 10-5. The inhibition efficiency percentage reaches the peak (90%) at optimum concentration of 250 ppm. The Monte Carlo simulations confirm the adsorption ability of the as-prepared compounds on the Fe (1 1 0) crystal. The SEM/EDX results revealed the presence of a protective film on the mild steel sample.

8.
J Phys Chem B ; 122(2): 527-533, 2018 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-28621937

RESUMO

Although the (111) surface of Fe3O4 (magnetite) has been investigated for more than 20 years, substantial controversy remains in the literature regarding the surface termination proposed based on structural and adsorption studies. The present article provides density functional theory results that allow to rationalize experimental results of infrared reflection-absorption spectroscopy and temperature-programmed desorption studies on CO adsorption, thus leading to a unified picture in which the Fe3O4(111) surface is terminated by a 1/4 monolayer of tetrahedrally coordinated Fe3+ ions on top of a close-packed oxygen layer as previously determined by low energy electron diffraction. However, surface defects play a crucial role in adsorption properties and may dominate chemical reactions on Fe3O4(111) when exposed to the ambient.

9.
RSC Adv ; 8(66): 37891-37904, 2018 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-35558626

RESUMO

The corrosion performance of carbon steel was tested in four polymeric ionic liquids (PILs) that differed only in the fatty acid linked to the chitosan (CS) amine group. The measurements were implemented involved the hydrogen evolution rate (HER), gravimetric measurements, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and quantum chemical estimations. The morphology and the elements arranged on the metal were considered by a scanning electron microscopy (SEM) system attached to an energy dispersive X-ray (EDX) system. The addition of polymeric ionic liquids hindered the rate of hydrogen generation. The order of the inhibitors efficiency was CSPTA-lauric > CSPTA-myristic > CSPTA-palmitic > CSPTA-stearic. The polarization method proved that the percentage inhibition efficiency increases with increasing the inhibitors concentration in 1 M HCl, representing a drop in the corrosion rate of carbon steel. On the other hand, the percentage inhibition decreased with the increase in temperature. Quantum chemical calculations revealed that the tested ionic liquids could react with the iron surface via electron transfer from the metal atom to ionic liquid molecule.

10.
Neurogastroenterol Motil ; 21(9): 936-e72, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19368653

RESUMO

Pediatric cyclic vomiting syndrome (CVS) is associated with a high prevalence of co-morbid migraine and other functional disorders, and with two adult migraine-associated mitochondrial DNA (mtDNA) polymorphisms: 16519T and 3010A. These potential associations have not been studied in adult CVS. The objective of this study is to determine the prevalence of 16519T and 3010A mtDNA polymorphisms and other functional disorders in adult CVS patients. Adults with CVS recruited from the University of Kansas meeting Rome III criteria and a population control group completed a self-reported survey that included questions relating to the diagnostic criteria for several functional disorders. DNA was isolated from blood or saliva and genotyping was performed by standard methodologies. Adult CVS subjects, compared to controls, had significantly more symptoms consistent with several other functional disorders. 16519T was present in 22/31 cases (71%) of child-onset (<12 years) and 9/31 (29%) cases of adult-onset (18+ years) CVS (P = 0.01), vs 27% of controls. Among subjects with 16519T, 3010A was present in 30% of child-onset vs 0% of adult-onset CVS (P = 0.05) and 2% of controls. The conclusions drawn were: (i) unlike pediatric CVS, adult CVS is not associated with the 16519T and 3010A mtDNA polymorphisms, suggesting a degree of genetic distinction and (ii) similar to the pediatric setting, adult CVS is associated with a substantial burden of co-morbid functional disorders.


Assuntos
DNA Mitocondrial/genética , Transtornos de Enxaqueca/complicações , Polimorfismo Genético/genética , Vômito/etiologia , Vômito/genética , Adolescente , Adulto , Fatores Etários , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Predisposição Genética para Doença , Inquéritos Epidemiológicos , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Síndrome , Vômito/epidemiologia , Adulto Jovem
11.
Cephalalgia ; 29(7): 719-28, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19220304

RESUMO

Mitochondrial dysfunction is a hypothesized component in the multifactorial pathogenesis of migraine without aura (MoA, 'common migraine') and the related condition of cyclic vomiting syndrome (CVS). In this study, the entire mitochondrial genome was sequenced in 20 haplogroup-H CVS patients, a subject group studied because of greater genotypic and phenotypic homogeneity. Sequences were compared against haplogroup-H controls. Polymorphisms of interest were tested in 10 additional CVS subjects and in 112 haplogroup-H adults with MoA. The 16519C-->T polymorphism was found to be highly disease associated: 21/30 CVS subjects [70%, odds ratio (OR) 6.2] and 58/112 migraineurs (52%, OR 3.6) vs. 63/231 controls (27%). A second polymorphism, 3010G-->A, was found to be highly disease associated in those subjects with 16519T: 6/21 CVS subjects (29%, OR 17) and 15/58 migraineurs (26%, OR 15) vs. 1/63 controls (1.6%). Our data suggest that these polymorphisms constitute a substantial proportion of the genetic factor in migraine pathogenesis, and strengthen the hypothesis that there is a component of mitochondrial dysfunction in migraine.


Assuntos
DNA Mitocondrial/genética , Predisposição Genética para Doença , Transtornos de Enxaqueca/genética , Vômito/genética , Adulto , Criança , Feminino , Humanos , Masculino , Transtornos de Enxaqueca/complicações , Polimorfismo de Fragmento de Restrição , Polimorfismo de Nucleotídeo Único , Síndrome , Vômito/etiologia
12.
J Appl Genet ; 50(1): 17-23, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19193978

RESUMO

Retroviral envelope (env)-like sequences in 2 cultivated allotetraploid cottons and their diploid progenitors have been identified and characterized in this study. DNA sequence analysis reveals that these sequences are heterogeneous. The observed sequence diversity, however, seems to preserve coding information. This is evidenced by the detection of the transmembrane domain (TM), which is the most conserved feature of the divergent retroviral env genes. The high ratio of synonymous to nonsynonymous changes suggests that these sequences are evolving under purifying selection. Phylogenetic analysis shows that Gossypium sequences closely cluster with a lineage of plant endogenous retroviruses that have an env-like gene. These results provide evidence for the antiquity and the wide diversity of env-like sequences in the Gossypium genome.


Assuntos
Gossypium/genética , Gossypium/virologia , Sequência de Aminoácidos , Linhagem da Célula , Análise por Conglomerados , Sequência Conservada , Primers do DNA/genética , Diploide , Produtos do Gene env/genética , Genes de Plantas , Dados de Sequência Molecular , Filogenia , Estrutura Terciária de Proteína , Retroelementos/genética , Retroviridae/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos
13.
Microb Ecol ; 43(2): 217-24, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12023728

RESUMO

Twelve selected phenol-degrading bacterial isolates were obtained on phenol agar plates using culture enrichment technique. Molecular identification of the isolates was performed using eubacterial 16S rRNA PCR specific primers. Based on 16S rDNA sequence analysis, the results revealed that the majority of the isolates (8 out of 12) are affiliated to the g-subdivision of Proteobacteria. Four out of the eight isolates are closely related to the genus Acinetobacter. Molecular heterogeneity among the phenol-degrading isolates was further investigated by using rep-PCR chromosomal fingerprinting and correlated with plasmid and antibiotic profile analysis. Rep-PCR results strongly confirmed that the bacterial isolates from different environmental sites produced different fingerprinting patterns. The mineralization of phenol by all isolates was evaluated using 14C-labeled phenol assay. Phenol mineralization ranged from 55% (W-17) to 0.4% (Sea-9). This was further confirmed by the detection of several monoaromatic and polyaromatic degrading genes, e.g., pheA, MopR, XylE, and NahA. In addition, catalytic enzymes such as catalase and dioxygenase were also monitored.


Assuntos
Acinetobacter/genética , Impressões Digitais de DNA , Desinfetantes/metabolismo , Fenol/metabolismo , Proteobactérias/genética , Acinetobacter/isolamento & purificação , Ecossistema , Egito , Reação em Cadeia da Polimerase , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S , Microbiologia do Solo
14.
J Biol Chem ; 274(37): 26079-84, 1999 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-10473556

RESUMO

The mechanisms and the functional importance of G-protein-coupled receptor dimerization are poorly understood. We therefore analyzed dimerization of the bradykinin B(2) receptor. The binding of the agonist bradykinin to the B(2) receptor endogenously expressed on PC-12 cells led to the formation of receptor dimers, whereas the B(2) antagonist HOE140 did not induce dimerization, suggesting that B(2) receptor dimerization was linked to receptor activation. Addition of a peptide corresponding to the amino terminus of the receptor reduced the amount of detected B(2) receptor dimers, whereas peptides derived from the extracellular loops had no effect. To further analyze the role of the amino terminus of the receptor in receptor dimerization, we created two different rat B(2) receptor variants with truncated amino termini, B(2)(53) and B(2)(65), starting at amino acids 53 and 65. In contrast to the wild-type B(2) receptor and to B(2)(53), bradykinin did not induce dimerization of the B(2)(65) receptor. Both receptor variants were similar to the wild-type B(2) receptor with respect to agonist binding and signal generation. However, B(2)(65) was not phosphorylated, did not desensitize, and was not downregulated upon bradykinin stimulation. Likewise, antibodies directed to the amino terminus of the receptor partially reduced internalization of [(3)H]bradykinin on PC-12 cells. These findings suggest that the amino terminus of the B(2) receptor is necessary for triggering agonist-induced B(2) receptor dimerization, and receptor dimers are involved in receptor-mediated signal attenuation.


Assuntos
Receptores da Bradicinina/agonistas , Receptores da Bradicinina/química , Animais , Bradicinina/metabolismo , Linhagem Celular , Dimerização , Regulação para Baixo , Humanos , Células PC12 , Ratos , Receptor B2 da Bradicinina
15.
Clin Chim Acta ; 283(1-2): 1-14, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10404726

RESUMO

Hepatitis C virus (HCV) is a major etiological factor in chronic hepatitis affecting up to 24% of blood donors in Egypt. Since fluctuating levels of HCV RNA loads, including undetectable values, have been frequently observed in sera of chronic hepatitis patients, this study was designed to assess the sensitivity of PCR amplification for the plus- and minus-RNA strands in peripheral blood mononuclear cells (PBMC) compared to single serum PCR assay. Since the latter test detects viremia in only 79.5% of seropositive cases, the highest sensitivity for HCV diagnosis was achieved (93.20% when applying the combined triple test including PCR amplification of plus-strand in serum, together with plus-strand in PBMC and minus-strand in PBMC. The results of this study indicate that the triple test provides significant information on extrahepatic replication of HCV in a sizable sample of seropositive subjects (429 cases) and improves the assessment of HCV viremia. The cost/effectiveness and speed were upgraded by using capillary/air rapid thermal cycler. The use of the triple assay in HCV diagnosis and post-therapy monitoring is recommended.


Assuntos
Hepacivirus/genética , Hepatite C/diagnóstico , Leucócitos Mononucleares/virologia , RNA Viral/sangue , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
16.
J Biol Chem ; 274(21): 14773-8, 1999 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-10329674

RESUMO

In analogy to the structure of rhodopsin, the seven hydrophobic segments of G-protein-coupled receptors are supposed to form seven membrane-spanning alpha-helices. To analyze the topology of the bradykinin B2 receptor, we raised site-directed antibodies to peptides corresponding to the loop regions and the amino and carboxyl terminus of this receptor. We found that a segment with predicted intracellular orientation according to the rhodopsin model, the connecting loop between membrane domains I and II of the bradykinin B2 receptor, was accessible to site-directed antibodies on intact fibroblasts, A431 cells, or COS cells expressing human B2 receptors. Extracellular orientation of this loop was further confirmed by the substituted cysteine accessibility method which showed that exchange of cysteine 94 for serine on this loop by point mutagenesis suppressed the effect of thiol modification by a membrane impermeant maleimide. In addition, this segment seemed to be involved in B2 receptor activation, since (i) thiol modification of cysteine 94 partially suppressed B2 receptor activation, and (ii) site-directed antibodies to the connecting loop between membrane domains I and II were agonists. The agonistic activity of the antibodies was suppressed by the B2 antagonist HOE140 confirming the B2 specificity of the antibody-generated signal. The extracellular orientation of the connecting loop between membrane domains I and II suggests a topology of the B2 receptor different from rhodopsin, consisting of five (instead of seven) transmembrane domains and two hydrophobic segments with both ends facing the extracellular side.


Assuntos
Receptores da Bradicinina/química , Anticorpos/imunologia , Reações Cruzadas , Cisteína , Espaço Extracelular , Citometria de Fluxo , Ligantes , Estrutura Terciária de Proteína , Receptor B2 da Bradicinina , Receptores da Bradicinina/imunologia , Compostos de Sulfidrila
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...