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2.
Eur Biophys J ; 49(1): 95-103, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31865397

RESUMO

We describe the dynamics of lipoic acid (LA) alone, incorporated in liposomes and as a part of nanoemulsions. Mass spectrometry shows that LA in water forms aggregates of two or three molecules in the form of a negatively charged ion and a neutral molecule. Phosphatidylcholine (PC)-based nanoforms of LA as liposomes and nanoemulsions with a particle size equal to 145 nm are characterized by a high degree of incorporation of LA into the nanoparticles and long-term stability during storage at room temperature. Dynamic light scattering (DLS) gives the polydispersity index of the nanoforms (> 0.3), characterizing the homogeneity of the obtained nanodispersions. We found that such emulsions can significantly (5 ×) increase the concentration of LA in the aqueous phase (5-7 mg/mL) when compared with an aqueous solution of LA (1 mg/mL) and by 40% when compared with PC liposomes (4 mg/mL). Moreover, the inclusion of LA in liposomes and nanoemulsions from PC did not change the neutral ζ-potential characteristic of PC nanoforms. CryoTEM established that the structural organization of the liposomes practically did not differ from nanoemulsions and both nanoforms contained both multilayer and single-layer vesicles. When studying the release kinetics of LA from phosphatidylcholine nanoforms, we found that at 22 h, 45-55% of LA was released from nanoparticles, but that at the initial stage of the process LA was slowly released from the nanoemulsions and rapidly from the liposomes. Conductance measurements indicate that LA delivered in all the three forms increase membrane permeability, though this result is most marked with the LA in PC liposomes.


Assuntos
Lipossomos/química , Nanopartículas/química , Fosfatidilcolinas/química , Ácido Tióctico/química , Emulsões/química
3.
J Biol Phys ; 45(4): 317-334, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31595390

RESUMO

This paper examines the effect of electromagnetic waves, with maxima in the green or red regions of the spectrum, on the morphofunctional state of multipotent mesenchymal stromal cells. The illumination regimes used in our experiments did not lead to any substantial heating of the samples; the physical parameters of the lighting were carefully monitored. When the samples were illuminated with a green light, no significant photostimulatory effect was observed. Red light, on the other hand, had an evident photostimulatory effect. It is shown that photostimulation with a red light decreases the enzymatic activities of mitochondrial dehydrogenases and enhances the viability of cells, their proliferative activity, and their ability to form bone tissue. It is also established that red light stimulates cell proliferation, while not activating the genes that increase the risk of the subsequent malignant transformation of cells or their death. This paper discusses the possible role of hydrogen peroxide in the processes examined.


Assuntos
Fenômenos Eletromagnéticos , Luz , Células-Tronco Mesenquimais/efeitos da radiação , Animais , Proliferação de Células/efeitos da radiação , Cor , Regulação da Expressão Gênica/efeitos da radiação , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Camundongos
5.
J Antimicrob Chemother ; 43(4): 483-90, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10350376

RESUMO

To compare the pharmacodynamics of trovafloxacin and ciprofloxacin, three clinical isolates of Staphylococcus aureus with different MICs (0.03, 0.15, 0.6 and 0.1, 0.25, 1.25 mg/L, respectively) were exposed to decreasing concentrations of the quinolones according to their half-lives of 9.25 and 4 h, respectively. With each organism, single doses of trovafloxacin and twice-daily doses of ciprofloxacin were designed to provide 8-fold ranges of the ratio of area under the concentration-time curve (AUC) to the MIC, 58-466 and 116-932 (mg x h/L)/(mg/L), respectively. The antimicrobial effect was expressed by its intensity: the area between the control growth in the absence of antibiotics and the antibiotic-induced time-kill/regrowth curves (I(E)). Linear relationships established between I(E) and log AUC/MIC were bacterial strain-independent but specific for the quinolones (r2 = 0.99 in both cases). At a given AUC/MIC ratio, the I(E)s of trovafloxacin were greater than those of ciprofloxacin, suggesting that the antimicrobial effect of trovafloxacin compared with ciprofloxacin against staphylococci may be even greater than might be expected from the difference in their MICs. These data were combined with previous results obtained with three Gram-negative bacteria. Again, I(E) correlated well with the log AUC/MIC of trovafloxacin and ciprofloxacin in a strain- and species-independent fashion (r2 = 0.94 and 0.96, respectively). On this basis, a value of the AUC/MIC of trovafloxacin which might be equivalent to Schentag's AUC/MIC = 125 (mg x h/L)/(mg/L) reported as the breakpoint value for ciprofloxacin was estimated at 71 (mg x h/L)/(mg/L) with the respective MIC breakpoint of 0.27 mg/L. Based on the I(E)-log AUC/MIC relationships, the I(E)s were plotted against the logarithm of trovafloxacin and ciprofloxacin dose (D) for hypothetical representatives of S. aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa with MICs corresponding to the MIC50s. These I(E)-log D relationships allow prediction of the effect of a given quinolone on a representative strain of the bacterial species.


Assuntos
Anti-Infecciosos/farmacologia , Ciprofloxacina/farmacologia , Fluoroquinolonas , Naftiridinas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Área Sob a Curva , Relação Dose-Resposta a Droga , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Humanos , Meticilina/farmacologia , Resistência a Meticilina , Testes de Sensibilidade Microbiana , Modelos Biológicos , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/isolamento & purificação
9.
Klin Lab Diagn ; (4): 21-4, 1997 Apr.
Artigo em Russo | MEDLINE | ID: mdl-9221072

RESUMO

An enzyme immunoassay kit based on monoclonal antibodies (Mab) has been developed for measuring thyroid-stimulating hormone in human serum and plasma. Laboratory trials demonstrated its high sensitivity (3.1 microIU/ml), specificity, reliability, and accuracy. The analysis is simple and rapid (2.5 h), which is convenient for clinical use. The kit permits differentiation between normal subjects and patients with primary hypo- or hyperthyroidism and helps monitor the treatment efficacy. Comparison with the Amerlite TSH-60 kit, carried out on 357 sera, showed a high correlation coefficient (0.96) between the two kits.


Assuntos
Técnicas Imunoenzimáticas , Kit de Reagentes para Diagnóstico , Tireotropina/sangue , Anticorpos Monoclonais , Diagnóstico Diferencial , Humanos , Hipertireoidismo/diagnóstico , Hipotireoidismo/diagnóstico , Sensibilidade e Especificidade
13.
Arkh Patol ; 58(2): 28-32, 1996.
Artigo em Russo | MEDLINE | ID: mdl-8712936

RESUMO

67 brain tumors were studied using monoclonal antibodies against glial fibrillary acid protein (GFAP), neurofilaments, proteoglycan, laminin and vimentin. All the astrocytic tumors gave positive reaction to GFAP, but anaplastic tumors of this type were less reactive. Medulloblastomas when treated with GFAP showed two cell lines, astrocytic and neuronal. A positive reaction to laminin and proteoglycan was observed in the vessels of neuroepithelial tumors. Anaplastic astrocytomas were more reactive to vimentin.


Assuntos
Biomarcadores Tumorais/análise , Neoplasias Encefálicas/diagnóstico , Proteínas de Neoplasias/análise , Anticorpos Monoclonais , Astrocitoma/diagnóstico , Neoplasias Encefálicas/química , Diagnóstico Diferencial , Proteína Glial Fibrilar Ácida/análise , Glioblastoma/diagnóstico , Humanos , Imuno-Histoquímica , Laminina/análise , Meduloblastoma/diagnóstico , Proteínas de Neurofilamentos/análise , Proteoglicanas/análise , Vimentina/análise
14.
Bioorg Khim ; 22(1): 34-8, 1996 Jan.
Artigo em Russo | MEDLINE | ID: mdl-8651954

RESUMO

The effect of hapten heterology on the characteristics of indirect ELISA methods for determination of thyroxine and triiodothyronine using monoclonal antibodies was studied. The use of the heterologous triiodothyronine-bovine serum albumin conjugate in immunoassays for thyroxine improved the sensitivity of these assays twofold and reduced the cross-reactivity with triiodothyronine from 1 to 0.5% as compared to the homologous variant. By contrast, the heterology in the immunoassays for triiodothyronine appeared inadequate. It was shown that the specificity and sensitivity of hapten immunoassays can be modulated by altering the chemical structure of the hapten-label conjugate, which is most evident in experiments with monoclonal antibodies.


Assuntos
Haptenos/imunologia , Tiroxina/análise , Tri-Iodotironina/análise , Anticorpos Monoclonais/imunologia , Ensaio de Imunoadsorção Enzimática , Sensibilidade e Especificidade , Soroalbumina Bovina/química , Tiroxina/imunologia , Tri-Iodotironina/imunologia
16.
Bioorg Khim ; 21(8): 632-5, 1995 Aug.
Artigo em Russo | MEDLINE | ID: mdl-8540904

RESUMO

Two variants (direct and indirect) of enzyme linked immunosorbent assay (ELISA) of phenobarbital are compared. Both techniques were developed on the basis of the same monoclonal antibodies, and horse radish peroxidase was used as the label in both cases. When microtitration plates are used as the solid phase, indirect ELISA, in which phenobarbital of the sample competes with phenobarbital sorbed on plates in the form of a conjugate with protein for the binding with peroxidase-labeled antiphenobarbital antibodies, is preferable. In indirect ELISA, the sample volume was 5 microliters, the time of assay was 40 min, the variability coefficient was < 8%.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Fenobarbital/análise , Animais , Anticorpos Monoclonais/imunologia , Peroxidase do Rábano Silvestre , Camundongos , Fenobarbital/imunologia
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