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1.
Small ; 20(11): e2305746, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37941496

RESUMO

Redox-induced interconversions of metal oxidation states typically result in multiple phase boundaries that separate chemically and structurally distinct oxides and suboxides. Directly probing such multi-interfacial reactions is challenging because of the difficulty in simultaneously resolving the multiple reaction fronts at the atomic scale. Using the example of CuO reduction in H2 gas, a reaction pathway of CuO → monoclinic m-Cu4 O3 → Cu2 O is demonstrated and identifies interfacial reaction fronts at the atomic scale, where the Cu2 O/m-Cu4 O3 interface shows a diffuse-type interfacial transformation; while the lateral flow of interfacial ledges appears to control the m-Cu4 O3 /CuO transformation. Together with atomistic modeling, it is shown that such a multi-interface transformation results from the surface-reaction-induced formation of oxygen vacancies that diffuse into deeper atomic layers, thereby resulting in the formation of the lower oxides of Cu2 O and m-Cu4 O3 , and activate the interfacial transformations. These results demonstrate the lively dynamics at the reaction fronts of the multiple interfaces and have substantial implications for controlling the microstructure and interphase boundaries by coupling the interplay between the surface reaction dynamics and the resulting mass transport and phase evolution in the subsurface and bulk.

2.
Reprod Domest Anim ; 59(1): e14523, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38268209

RESUMO

Kisspeptin (Kp), an upstream regulator of GnRH release, is essential for the development and function of reproductive axis. Previously, we demonstrated the localization of Kp and its receptor (Kiss1r) in the active follicle in the bubaline ovary. Present study aimed to determine the effect of Kp on granulosa cell (GCs) functions, especially oestradiol (E2 ) and progesterone (P4 ) production, and differential expression of genes regulating the proliferation, apoptosis and steroidogenesis in the buffalo. The ovaries with 6-10 mm size follicles obtained from the cyclic buffaloes after slaughtering were used for isolation of GCs for in vitro study. The primary GCs culture was treated with Kp (0, 10, 50 and 100 nM) and incubated for 48 h. Production of E2 and P4 was estimated in the culture supernatant by ELISA. The expression of gonadotropin receptors (FSHR and LHR), steroidogenic genes (STAR, 3ß-HSD, CYP19A1), proliferation marker (PCNA), apoptotic factors (CASP3 and BCL2) and Kp signalling molecule (extracellular signal-regulated kinase 1/2, ERK1/2 and p-ERK1/2) was studied in the GCs by qPCR. Significant E2 production was found in the Kp 50 and 100 nM groups (p < .05), whereas P4 production was reduced in Kp 100 nM group (p < .05). There was concomitant upregulation of FSHR, ERK1/2, STAR and CYP19A1 in the Kp 100 nM treated GCs. In addition, Kp at 100 nM stimulated the proliferation of GCs by upregulating the expression of BCL2 (5.0 fold) and PCNA (94.9 fold). Further, high immunoreactivity of p-ERK1/2 was observed in the Kp-treated GCs. It was concluded that Kp at 100 nM concentration stimulated E2 production by upregulating the steroidogenic pathway through ERK1/2, STAR and CYP19A1 and modulating PCNA and BCL2 expressions in the GCs. Further experiments are warranted using Kp antagonist in different combinations to establish the signalling pathway in Kp-mediated steroidogenesis in the GCs for developing strategies to control ovarian functions.


Assuntos
Bison , Estradiol , Animais , Feminino , Kisspeptinas/genética , Antígeno Nuclear de Célula em Proliferação , Células da Granulosa , Proliferação de Células , Proteínas Proto-Oncogênicas c-bcl-2
3.
Neuroimmunomodulation ; 30(1): 196-205, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37336193

RESUMO

The assumption of the pineal hormone melatonin as a therapeutic use for COVID-19-affected people seems promising. Its intake has shown significant improvement in the patients' conditions. Higher melatonin titers in children may provide a protective shield against this disease. The hormone melatonin works as an anti-inflammatory, antioxidant, immunomodulator, and strategically slows down the cytokine release which is observed in the COVID-19 disease, thereby improving the overall health of afflicted patients. The medical community is expected shortly to use remedial attributes like anti-inflammatory, antioxidant, antivirals, etc., of melatonin in the successful prevention and cure of COVID-19 morbidity. Thus, the administration of melatonin seems auspicious in the cure and prevention of this COVID-19 fatality. Moreover, melatonin does not seem to reduce the efficiency of approved vaccines against the SARS-CoV-2 virus. Melatonin increases the production of inflammatory cytokines and Th1 and enhances both humoral and cell-mediated responses. Through the enhanced humoral immunity, melatonin exhibits antiviral activities by suppressing multiple inflammatory products such as IL-6, IL1ß, and tumor necrosis factor α, which are immediately released during lung injury of severe COVID-19. Hence, the novel use of melatonin along with other antivirals as an early treatment option against COVID-19 infection is suggested. Here, we have chalked out the invasion mechanisms and appropriate implications of the latest findings concerned with melatonin against the virus SARS-CoV-2. Nevertheless, within the setting of a clinical intervention, the promising compounds must go through a series of studies before their recommendation. In the clinical field, this is done in a time-ordered sequence, in line with the phase label affixed to proper protocol of trials: phase I-phase II and the final phase III. Nevertheless, while medical recommendations can only be made on the basis of reassuring evidence, there are still three issues worth considering before implementation: representativeness, validity, and lastly generalizability.


Assuntos
COVID-19 , Melatonina , Criança , Humanos , Melatonina/uso terapêutico , SARS-CoV-2 , Antioxidantes/uso terapêutico , Antivirais/uso terapêutico , Anti-Inflamatórios/uso terapêutico
4.
Environ Res ; 234: 116555, 2023 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-37419199

RESUMO

An easy synthesis of two 1,3,4-oxadiazole derivatives, namely, 2-phenyl-5-(pyridin-3-yl)-1,3,4-oxadiazole (POX) and 2-(4-methoxyphenyl)-5-(pyridin-3-yl)-1,3,4-oxadiazole (4-PMOX), and their corrosion-inhibition efficacy against mild steel corrosion in 1 N HCl, is evaluated using weight loss from 303 to 323 K, Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), UV-Vis spectroscopy, along with theoretical evaluation. Both POX and 4-PMOX exhibit excellent inhibition efficiency, with values reaching 97.83% and 98% at 500 ppm, respectively. The PDP analysis reveals that both derivatives act as mixed-type inhibitors. The Langmuir adsorption isotherm provides insights into the adsorption phenomena, demonstrating that 4-PMOX exhibits superior adsorption behavior on the mild steel surface compared to POX. This finding is further supported by SEM, DFT, RDF, and MSD analyses. Quantum mechanical parameters, including EHOMO, ELUMO, dipole moment (µ), energy gap (ΔE), etc., are in good agreement with the effectiveness of inhibition performance revealing ΔE values of 3.10 and 2.75 for POX and 4-PMOX, respectively. The results obtained from this study hold significant implications for researchers aiming to design more efficient organic inhibitors to combat metal corrosion.


Assuntos
Oxidiazóis , Aço , Aço/química , Corrosão , Piridinas
5.
Mol Divers ; 27(2): 889-900, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35781657

RESUMO

Individually, hydroxycoumarin and amino pyrimidine derivatives are of significant biological interest owing to their importance in drugs and pharmaceuticals. To access their combined biological impact into one molecule, we designed a novel, one-pot green approach for synthesizing trisubstituted methanes. A series of new heteroaryl-substituted methanes have been synthesized and subjected to in vitro antibacterial and antioxidant evaluation. Tests against clinical isolates of Escherichia coli (gram-negative) and Staphylococcus aureus showed potent activity of the derivatives 4a, 4b, 4d, 4e, 4f, 4l, and 5 against the former, and 4a, 4e, 4j, and 4l against the later one. Further, antioxidant assay for these TRSMs was also studied where 4a, 4b, 4f, 4j, and 4l exhibited the most promising results. These preliminary bioassay evaluations strongly suggest the promise and scope of these molecules in medical science. A one pot methodology for the synthesis of coumarin and uracil tethered trisubstituted methanes has been reported. The synthesized derivatives were further analyzed for their antibacterial and antioxidant properties to explore their medicinal applications. The salient features of this methodology are operational simplicity, short reaction time, good to moderate yields of the products, easy purification method. Biochemical assay of the synthesized TRSMs a reveals their utility in medicinal & pharma industry.


Assuntos
Antioxidantes , Metano , Antioxidantes/química , Antibacterianos/química , Catálise , Testes de Sensibilidade Microbiana
6.
Reprod Domest Anim ; 58(11): 1604-1611, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37727883

RESUMO

Pyometra is a potentially life-threatening condition that affects intact female dogs in their middle to advance age. Timely diagnosis and appropriate treatment are critical for the survival of patients, especially when pyometra advances to sepsis. This study aimed to investigate the prognostic potential of certain haematology, serum biochemical and inflammatory biomarker, secretory leucocyte protease inhibitor (SLPI) for pyometra in bitches (n = 41). Blood samples were collected after clinical diagnosis of pyometra for haematology and serum biochemistry. Based on the prognosis following medical/surgical treatment, animals were retrospectively categorized into survivor (n = 29) and dead (n = 12). Endometrial tissue sections were obtained from the bitches undergoing ovariohysterectomy (n = 21). Serum concentration of SLPI was quantified using sandwich ELISA and its expression in the endometrium was investigated using RT-qPCR. A marked increase in the total leucocyte count (TLC), neutrophils, blood urea nitrogen (BUN) and serum creatinine was observed in the female dogs that did not survive. Significant elevation in the serum SLPI concentration (3.49 ± 0.44 vs. 2.38 ± 0.13 ng/mL) was observed in the bitches those died after the treatment, in comparison to those survived (p < .01). Additionally, there was a notable upregulation of SLPI in the endometrium in the bitches those died due to pyometra. Based on the ROC analysis results, it was observed that a cut-off concentration of 2.93 ng/mL for SLPI, 27.77 mg/dL for BUN and 16.3 × 103 /µL for TLC could effectively distinguish the prognosis of pyometra-affected dogs. From this study, it can be concluded that upregulation of SLPI in the endometrium and its elevated concentration in peripheral circulation along with TLC and BUN concentration could serve as valuable indicators for predicting the prognosis of pyometra in bitches.


Assuntos
Doenças do Cão , Piometra , Humanos , Cães , Animais , Feminino , Piometra/veterinária , Estudos Retrospectivos , Prognóstico , Biomarcadores , Inibidores de Proteases , Inibidor Secretado de Peptidases Leucocitárias
7.
Reprod Domest Anim ; 58(11): 1622-1627, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37743827

RESUMO

Sexed semen facilitates additional female calf production for the expansion of a herd at a faster rate and also curtails the surplus production of unwanted male calves. A study was conducted to evaluate the performance of sexed semen in indigenous Tharparkar cows based on 114 artificial inseminations (AI) performed at natural oestrus using two protocols i.e., single AI (n = 48) and double AI (n = 66). Overall, the first service conception rate (CR) was significantly higher in double (53.0%) than single (33.3%) AI protocol. The odds ratio of conception rate in double AI was 2.26 (χ2 = 4.4, df = 1, p = .04) with respect to single AI. The time that elapsed since the detection of oestrus to insemination was also analysed. In a single AI protocol, the CR was higher (p < .05) at 16 h (54.6%) than insemination at 8 h (27.0%) following the onset of oestrus. Yet, the CR using double AI protocol did not differ (p = .73) significantly when AIs were performed either at 8 h and 24 h (51.9%) or 16 h and 24 h (57.1%) post onset of oestrus. Besides, like the single AI protocol, the parity of the animals also influenced the CR, being higher in heifers (n = 22) than those of parous (n = 92) cows (72.73 vs. 40.43%, χ2 = 7.48, df = 1, p = .006) in the present study. The odds ratio of conception in heifers was 3.93 with respect to parous cows. Overall, the birth of female calf was 91.7%. In conclusion, the present study indicates a future promise of the sexed semen for the production of more female offspring from Tharparkar cattle.


Assuntos
Sêmen , Pré-Seleção do Sexo , Animais , Bovinos , Feminino , Masculino , Fazendas , Pré-Seleção do Sexo/veterinária , Pré-Seleção do Sexo/métodos , Indústria de Laticínios/métodos , Inseminação Artificial/veterinária , Inseminação Artificial/métodos
8.
Fish Physiol Biochem ; 49(6): 1511-1525, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37982969

RESUMO

The pineal hormone melatonin is a multi-functional molecule with a recognized role in pigment aggregation in chromatophores, mediating its actions through binding to subtypes of its specific receptors. Since its discovery, melatonin has been known to be responsible for pigment aggregation towards the cell centre in fishes, including their embryos, as an adaptation to reduced light and thus results in pale body colouration. Diversity exists in the sensitivity of melanophores towards melatonin at interspecies, intraspecific levels, seasons, and amongst chromatophores at different regions of the animal body. In most of the fishes, melatonin leads to their skin paling at night. It is indicated that the melatonin receptors have characteristically maintained to show the same aggregating effects in fishes and other vertebrates in the evolutionary hierarchy. However, besides this aggregatory effect, melatonin is also responsible for pigment dispersion in certain fishes. Here is the demand in our review to explore further the nature of the dispersive behaviour of melatonin through the so-called ß-melatonin receptors. It is clear that the pigment translocations in lower vertebrates under the effect of melatonin are mediated through the melatonin receptors coupled with other hormonal receptors as well. Therefore, being richly supplied with a variety of receptors, chromatophores and melanocytes can be used as in vitro test models for pharmacological applications of known and novel drugs. In this review, we present diverse effects of melatonin on chromatophores of fishes in particular with appropriate implications on most of the recent findings.


Assuntos
Cromatóforos , Melatonina , Animais , Melatonina/farmacologia , Melatonina/metabolismo , Receptores de Melatonina/metabolismo , Peixes/metabolismo , Melanóforos , Vertebrados/metabolismo
9.
Nat Mater ; 20(3): 346-352, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33139891

RESUMO

Metallic nanoparticles have been used to harvest energy from a light source and transfer it to adsorbed gas molecules, which results in a reduced chemical reaction temperature. However, most reported reactions, such as ethylene epoxidation, ammonia decomposition and H-D bond formation are exothermic, and only H-D bond formation has been achieved at room temperature. These reactions require low activation energies (<2 eV), which are readily attained using visible-frequency localized surface plasmons (from ~1.75 eV to ~3.1 eV). Here, we show that endothermic reactions that require higher activation energy (>3.1 eV) can be initiated at room temperature by using localized surface plasmons in the deep-UV range. As an example, by leveraging simultaneous excitation of multiple localized surface plasmon modes of Al nanoparticles by using high-energy electrons, we initiate the reduction of CO2 to CO by carbon at room temperature. We employ an environmental transmission electron microscope to excite and characterize Al localized surface plasmon resonances, and simultaneously measure the spatial distribution of carbon gasification near the nanoparticles in a CO2 environment. This approach opens a path towards exploring other industrially relevant chemical processes that are initiated by plasmonic fields at room temperature.

10.
Indian J Med Res ; 155(3&4): 387-396, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-36124513

RESUMO

Background & objectives: Obesity is a rising pandemic in childhood. There is scarcity of evidence on the efficacy of yoga in achieving weight loss in overweight/obese children. The objective of this study was to assess the efficacy of family-based comprehensive yoga intervention in the reduction of body mass index (BMI) in overweight/obese children, in comparison to standard dietary and lifestyle counselling and control group. Methods: This was an open-label randomized controlled study. Children aged 8-15 yr who were overweight or had obesity were randomized to one of the three arms for 18 wk; standard weight management (group 1), yoga with dietary modification (group 2) and control (no intervention; group 3). Reduction in BMI and improvement in physiological, biochemical and psychological parameters from baseline to 18 wk was compared between the three arms. Late follow up was also done at 6-12 months. Results: A total of 165 children with mean±standard deviation (SD) age of 11.6±1.8 yr and mean BMI 26.3±4.2 kg/m2 were enrolled. Outcome analysis at 18 wk was performed for 109 children. Improved diet quality and reduced intake were observed in both intervention arms. The median (IQR) reduction in BMI in standard and yoga arms was similar [-1.4 (-3.1, -0.5) kg/m2 and -1.2 (-2.3, -0.6) kg/m2, respectively], while it increased by +0.3 (-0.3, 0.1) in the control arm. In the yoga arm, mean systolic BP reduced from 118 (10) to 114 (8) mmHg, (P=0.019). In the standard arm, significant improvement in psychological scores was noted. In group 3, the mean fasting glucose increased from 93±10 to 102±12 mg/dl (P<0.001). Interpretation & conclusions: The findings of the present study suggest that yoga in conjunction with dietary modification is equally effective as the standard weight management for BMI reduction in the paediatric age group.


Assuntos
Obesidade Infantil , Yoga , Adolescente , Criança , Glucose , Humanos , Sobrepeso , Obesidade Infantil/terapia , Redução de Peso
11.
Nat Mater ; 18(6): 614-619, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30988449

RESUMO

Recent reports of hot-electron-induced dissociation of small molecules, such as hydrogen, demonstrate the potential application of plasmonic nanostructures for harvesting light to initiate catalytic reactions. Theories have assumed that plasmonic catalysis is mediated by the energy transfer from nanoparticles to adsorbed molecules during the dephasing of localized surface plasmon (LSP) modes optically excited on plasmonic nanoparticles. However, LSP-induced chemical processes have not been resolved at a sub-nanoparticle scale to identify the active sites responsible for the energy transfer. Here, we exploit the LSP resonance excited by electron beam on gold nanoparticles to drive CO disproportionation at room temperature in an environmental scanning transmission electron microscope. Using in situ electron energy-loss spectroscopy with a combination of density functional theory and electromagnetic boundary element method calculations, we show at the subparticle level that the active sites on gold nanoparticles are where preferred gas adsorption sites and the locations of maximum LSP electric field amplitude (resonance antinodes) superimpose. Our findings provide insight into plasmonic catalysis and will be valuable in designing plasmonic antennas for low-temperature catalytic processes.

12.
Oncology ; 98(7): 478-486, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32434184

RESUMO

INTRODUCTION: Metastatic breast cancer has poor prognosis due to limited therapeutic options. Protein kinase dysregulations have a major role in breast cancer progression and metastasis. In this study, we investigated the anti-cancer activity of sorafenib, a multikinase inhibitor, which targets receptor tyrosine kinases in breast cancer. Although treatment with sorafenib has increased the patient survival and inhibited metastatic migration in hepatocellular carcinoma, its role in breast cancer migration, metastasis, and intracellular signaling modulation is unknown. METHODS: Breast cancer cell lines MCF7 and MDA-MB-231 were treated with sorafenib and its effect on proliferation, migration, invasion and gene expression was analyzed. RESULTS: We found that sorafenib has an anti-proliferative and cytotoxic effect on breast cancer cells. Importantly, sorafenib inhibited the migration and invasion of breast cancer cells in vitro. Mechanistically, sorafenib increased mitochondrial superoxide production, suppressed breast cancer stem cell self-renewal, inhibited epithelial mesenchymal transition and ERK signaling. CONCLUSION: Thus, sorafenib has anti-cancer activity against breast cancer cells and could improve the survival of breast cancer patients by inhibiting their invasive and metastatic properties.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sorafenibe/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Células MCF-7 , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Invasividade Neoplásica/prevenção & controle , Superóxidos/metabolismo
13.
Adv Funct Mater ; 30(4)2019.
Artigo em Inglês | MEDLINE | ID: mdl-33029110

RESUMO

A fundamental knowledge of the unidirectional growth mechanisms is required for precise control on size, shape, and thereby functionalities of nanostructures. The oxidation of many metals results in oxide nanowire growth with a bicrystal grain boundary along the axial direction. Using transmission electron microscopy that spatially and temporally resolves CuO nanowire growth during the oxidation of copper, here we provide direct evidence of the correlation between unidirectional crystal growth and bicrystal grain boundary diffusion. Based on atomic scale observations of the upward growth at the nanowire tip, oscillatory downward growth of atomic layers on the nanowire sidewall and the parabolic kinetics of lengthening, bicrystal grain boundary diffusion is the mechanism by which Cu ions are delivered from the nanowire root to the tip. Together with density-functional theory calculations, we further show that the asymmetry in the corner-crossing barriers promotes the unidirectional oxide growth by hindering the transport of Cu ions from the nanowire tip to the sidewall facets. We expect the broader applicability of these results in manipulating the growth of nanostructured oxides by controlling the bicrystal grain boundary structure that favors anisotropic diffusion for unidirectional, one-dimensional crystal growth for nanowires or isotropic diffusion for two-dimensional platelet growth.

14.
Cell Tissue Res ; 378(3): 531-542, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31377878

RESUMO

Mesenchymal stem cells (MSCs) are used extensively in cell therapy for repair and regeneration of several organs and tissues. Cell therapy is a valuable option to treat neurodegenerative diseases and MSCs have been shown to improve neuronal function through direct differentiation or secretion of neurotrophic factors. In the present study, we isolated and characterized stem cells from medial and central orbital adipose tissue and found that they could be grown in a monolayer culture. The orbital adipose tissue-derived cells were identical to bone marrow-derived MSCs in their cell surface marker expression, gene expression and multilineage differentiation abilities. The orbital adipose-derived MSCs (OAMSCs) express several neurotrophic factors, possess neuroectodermal differentiation ability and secreted factors from OAMSCs abrogated neuronal cell damage induced by oxidative stress. Thus, OAMSCs might be a valuable cell source for treatment of neurological diseases and to reverse oxidative damage in the neuronal cells.


Assuntos
Tecido Adiposo/citologia , Terapia Baseada em Transplante de Células e Tecidos/métodos , Pálpebras/citologia , Células-Tronco Mesenquimais/citologia , Proliferação de Células , Células Cultivadas , Humanos , Estresse Oxidativo , Cultura Primária de Células/métodos , Transcriptoma
15.
Angew Chem Int Ed Engl ; 58(27): 9204-9209, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31132208

RESUMO

Synthesis of low-dimensional carbon nanomaterials such as carbon nanotubes (CNTs) is a key driver for achieving advances in energy storage, computing, and multifunctional composites, among other applications. Here, we report high-yield thermal chemical vapor deposition (CVD) synthesis of CNTs catalyzed by reagent-grade common sodium-containing compounds, including NaCl, NaHCO3 , Na2 CO3 , and NaOH, found in table salt, baking soda, and detergents, respectively. Coupled with an oxidative dehydrogenation reaction to crack acetylene at reduced temperatures, Na-based nanoparticles have been observed to catalyze CNT growth at temperatures below 400 °C. Ex situ and in situ transmission electron microscopy (TEM) reveal unique CNT morphologies and growth characteristics, including a vaporizing Na catalyst phenomenon that we leverage to create CNTs without residual catalyst particles for applications that require metal-free CNTs. Na is shown to synthesize CNTs on numerous substrates, and as the first alkali group metal catalyst demonstrated for CNT growth, holds great promise for expanding the understanding of nanocarbon synthesis.

16.
Chemistry ; 24(15): 3729-3732, 2018 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-29388268

RESUMO

The histidine derivative L1 of the DNA intercalator naphthalenediimide (NDI) forms a triangular AgI complex (C2). The interactions of L1 and of C2 with DNA were studied by circular dichroism (CD) and UV/Vis spectroscopy and by viscosity studies. Different binding modes were observed for L1 and for C2, as the AgI complex C2 is too large in size to act as an intercalator. If AgI is added to the NDI molecule that is already intercalated into a duplex, higher order complexes are formed within the DNA duplex and cause disruptions in the helical duplex structure, which leads to a significant decrease in the characteristic CD features of B-DNA. Thus, via addition of a metal we show how a classic and well-known organic intercalator unit can be turned into a partial metallo insertor. We also show how electrochemical impedance spectroscopy (EIS) can be used to probe DNA binding modes on DNA films that are immobilized on gold surfaces.


Assuntos
DNA/química , Prata/química , Dicroísmo Circular , DNA de Forma B/química , Ouro/química , Imidas/química , Substâncias Intercalantes/química , Naftalenos/química
17.
J Biomed Sci ; 25(1): 5, 2018 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-29351753

RESUMO

BACKGROUND: Mesenchymal stem cells (MSC) are used for several therapeutic applications to improve the functions of bone, cardiac, nervous tissue as well as to facilitate the repopulation of hematopoietic stem cells. MSC give rise to the non-hematopoietic stromal cells of the bone marrow and are important for the maintenance of normal hematopoiesis. Chemotherapeutic drugs used for treatment of leukemia extensively damage the stromal cells and alter their gene expression profiles. METHODS: We determined the changes in adipogenic, osteogenic differentiation, phenotypic and gene expression in MSC during treatment with chemotherapeutic drugs cytarabine, daunorubicin and vincristine. We also tested anti-cancer effects of drug treated MSC on leukemia cells. RESULTS: Treatment with the chemotherapeutic drugs resulted in functional defects in MSC, leading to reduced proliferation, osteogenic and adipogenic differentiation. The drug treated MSC also showed decreased expression of cell surface receptors, and the changes in proliferation, phenotype and differentiation defect was partially reversible after withdrawing the drugs from the cells. The drug treated MSC showed increased expression of cytokines, IL6, FGF2 and TNFA but reduced levels of differentiation markers SOX9 and ACTC1. Drug treated MSC also contributed to reduced anti-cancer effects in leukemia cells. CONCLUSIONS: Chemotherapeutic drug treatment altered the phenotype, osteogenic and adipogenic differentiation potential of MSC and modified the gene expression profile of the cells to render them more chemoprotective of the leukemic cells. Thus, additional therapeutic efforts to target the stromal cell population will help in preventing chemoresistance, disease relapse in leukemia and to maintain a healthy bone marrow stroma.


Assuntos
Antígenos de Superfície/efeitos dos fármacos , Antineoplásicos/efeitos adversos , Diferenciação Celular/efeitos dos fármacos , Células-Tronco Mesenquimais/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Citarabina/efeitos adversos , Daunorrubicina/efeitos adversos , Células-Tronco Mesenquimais/fisiologia , Vincristina/efeitos adversos
18.
Analyst ; 143(12): 2844-2850, 2018 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-29786706

RESUMO

Hg(ii) binding to thymine-rich oligonucleotides (ODNs) is investigated electrochemically. The focus of this study is to probe the effects of position on the electrochemical response. For this purpose, three oligonucleotides were investigated in which the position of a hexa-thymine repeat is varied within a surface-supported oligonucleotide. The hexa repeats were placed in the top, middle, and bottom positions within the strand with respect to the gold surface. The effects were monitored by electrochemical impedance spectroscopy and scanning electrochemical microscopy. Using charge transfer resistance (RCT) and tip current (I) as a measure, it was possible to monitor the effects of Hg(ii) binding to the ds-oligonucleotide. The extent of film resistance reduces as the T-rich region moves from the bottom to top position within the film. The T-rich region closer to the gold surface probably builds less flexible and more rigid T-Hg(ii)-T basepairs compared to the other two positions and is expected to stay in the upright orientation on the surface. This in turn results in significant differences in the electrochemical readout, demonstrating that the position of T-rich sequences within an oligonucleotide strand matters.


Assuntos
Técnicas Eletroquímicas , Mercúrio/química , Oligonucleotídeos/química , Timina/química , Ouro
19.
Microsc Microanal ; 29(Supplement_1): 1942-1943, 2023 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-37612970
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