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1.
J Photochem Photobiol B ; 236: 112587, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36283255

RESUMO

Nanoemulsions are increasingly gaining importance in the development of topically applied medicine and cosmetic products because their small droplets favor the penetration rates of active compounds into the body. In this scenario, the measurements of their diffusion rates as well as eventual physicochemical changes in the target tissues are of utmost importance. It is also recognized that the use of natural surfactants can avoid allergic reactions as frequently observed for synthetic products. The natural saponins extracted from Sapindus Saponaria have the property of forming foam and are exploited as biocompatible and biodegradable, while cellulose nanocrystals are known to increase the stability of a formulation avoiding the coalescence of drops at the interface. Therefore, nanoemulsions combining natural saponins and cellulose nanocrystals are promising systems that may facilitate greater diffusion rates of molecules into the skin, being candidates to substitute synthetic formulations. This study applied the Photoacoustic Spectroscopy technique to measure the diffusion rates and the physicochemical properties of nanoemulsified formulations containing saponins and cellulose nanocrystals topically applied to the skin. The ex vivo study combined the first-time photoacoustic measurements performed in both ultraviolet-visible and mid-infrared spectral regions. The toxicity of these formulations in L929 cells was also evaluated. The results showed that the formulations were able to propagate throughout the skin to a depth of approximately 756 µm, reaching the dermal side. The non-observation of absorbing band shifting or new bands in the FTIR spectra suggests that there were no structural changes in the skin as well as in the formulations after the nanoemulsions administration. The cytotoxicity results showed that the increase of cellulose nanocrystals concentration decreased cellular toxicity. In conclusion, the results demonstrated the advantage of combining photoacoustic methods in the ultraviolet-visible and mid-infrared spectral regions to analyze drug diffusion and interaction with the skin tissues. Both methods complement each other, allowing the confirmation of the nanoemulsion diffusion through the skin and also suggesting there were no detectable physicochemical changes in the tissues. Formulations stabilized with saponins and cellulose nanocrystals showed great potential for the development of topically administered cosmetics and drugs.


Assuntos
Nanopartículas , Saponinas , Espectroscopia de Infravermelho com Transformada de Fourier , Celulose , Saponinas/farmacologia , Nanopartículas/química , Preparações Farmacêuticas , Emulsões/química
2.
J Photochem Photobiol B ; 227: 112379, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34998114

RESUMO

In this work the thermal diffusivity (D) of Astyanax lacustris fish scale is investigated aiming to use it for environmental integrity certification. The D values were obtained by a relatively simple procedure by a photoacoustic method. The chosen fish species is from wide occurrence in Brasil's basins. It has short migration, and it has also been used as environmental bioindicator. The results obtained in 195 scales sampled from three different streams in the Midwest region in Brazil gives an average value of D ~ 4 × 10-3 cm2/s. ANCOVA analysis demonstrated that D values are able to differentiate among the three basins and indicates that it is dependent on the scales thickness and water conductivity. This last one is strongly affected by biotic and abiotic actions, so that D values measured by photoacoustic method can be used for interpreting the environmental integrity from where the fishes were sampled.


Assuntos
Monitoramento Ambiental , Peixes , Animais , Brasil , Ecossistema , Monitoramento Ambiental/métodos , Análise Espectral
3.
J Dent Res ; 92(7): 661-5, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23632810

RESUMO

The aim of this study was to investigate the diffusion dynamics of 25% hydrogen peroxide (H2O2) through enamel-dentin layers and to correlate it with dentin's structural alterations. Micro-Raman Spectroscopy (MRS) and Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) were used to measure the spectra of specimens before and during the bleaching procedure. H2O2 was applied to the outer surface of human enamel specimens for 60 minutes. MRS measurements were performed on the inner surface of enamel or on the subsurface dentin. In addition, H2O2 diffusion dynamics from outer enamel to dentin, passing through the dentin-enamel junction (DEJ) was obtained with Raman transverse scans. FTIR-PAS spectra were collected on the outer dentin. MRS findings revealed that H2O2 (O-O stretching µ-Raman band) crossed enamel, had a more marked concentration at DEJ, and accumulated in dentin. FTIR-PAS analysis showed that H2O2 modified dentin's organic compounds, observed by the decrease in amides I, II, and III absorption band intensities. In conclusion, H2O2 penetration was demonstrated to be not merely a physical passage through enamel interprismatic spaces into the dentinal tubules. H2O2 diffusion dynamics presented a concentration gradient determined by the chemical affinity of the H2O2 with each specific dental tissue.


Assuntos
Esmalte Dentário/metabolismo , Dentina/metabolismo , Peróxido de Hidrogênio/farmacocinética , Clareadores Dentários/farmacocinética , Adolescente , Adulto , Amidas/análise , Fenômenos Bioquímicos , Carbono/química , Criança , Cor , Esmalte Dentário/efeitos dos fármacos , Dentina/efeitos dos fármacos , Dentina/ultraestrutura , Difusão , Humanos , Hidrogênio/química , Peróxido de Hidrogênio/farmacologia , Microespectrofotometria , Oxigênio/química , Técnicas Fotoacústicas , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Fatores de Tempo , Clareadores Dentários/farmacologia , Adulto Jovem
4.
Opt Express ; 20(9): 10034-41, 2012 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-22535094

RESUMO

In this paper we report results of tunable lighting in Ce(3+)/Eu(2+,3+) doped low silica calcium aluminosilicate glass. Optical spectroscopy experiments indicate that there is a red color compensation from Eu(2+) and Eu(3+) to the green emission from Ce(3+), resulting in a broad and tunable emission spectra depending on the excitation wavelength. This result analysed in the CIE 1976 color diagram shows a close distance from the Plank emission and a correlated color temperature, varying from 5200 to 3500K. This indicates that our system can be easily excited by GaN based blue LEDs, being an interesting phosphor for white lighting devices.


Assuntos
Césio/química , Cor , Vidro/química , Iluminação/instrumentação , Refratometria/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento
5.
J Phys Chem B ; 114(17): 5657-60, 2010 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-20387870

RESUMO

Optical properties of highly transparent blends formed by bisphenol A polycarbonate (PC) and poly(methyl methacrylate) (PMMA) and doped with either europium(III) thenoyltrifluoroacetone hydrate [Eu(TTA)(3)-hydrate] or terbium(III) acetylacetonate hydrate [Tb(ACAC)(3)-hydrate] were studied. From the absorption/emission spectra (200 to 800 nm), percolation limits of less than 0.4 wt/wt% for Eu and above 0.7 wt/wt% for Tb were found. Lifetimes for 20/80 and 60/40 Tb-doped blends were from 1.0 to 1.5 ms, respectively, about 5 times longer than for a similar blend prepared with Langmuir-Blodgett film. For blends doped with Eu, the lifetimes were from 0.4 to 0.8 ms, almost double that for the pure complex. The results indicated interactions between the PC/PMMA blends and the rare-earth ion complex. Particularly, photoluminescent spectra evidenced the incorporation of the Eu(3+) and Tb(3+) ions into the blend, with quenching observed near 1.0 wt/wt%, except for the 20/80 blend doped with Eu ion, in which luminescence increased to 5 wt/wt %.

6.
Opt Lett ; 35(7): 1055-7, 2010 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-20364215

RESUMO

We recently reported that Ti(3+)-doped low-silica calcium aluminosilicate glass presents long luminescence lifetime (170 micros) and broad emission band (190 nm) shifted toward the visible region when compared with those from Ti(3+):sapphire single crystal and Ti(3+)-doped glasses [Phys. Rev. Lett.100, 027402 (2008)]. Here we demonstrate that this glass also shows high values of both gain cross section (approximately 4.7 x 10(-19) cm(2)) and luminescence quantum efficiency (approximately 70%). By comparing these values with those for Ti(3+):sapphire crystal, we can conclude that the studied Ti(3+)-doped glass is a promising system for tunable solid-state lasers.

7.
Talanta ; 81(1-2): 202-7, 2010 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-20188909

RESUMO

Photoacoustic spectroscopy (PAS) was applied as a method to quantify dyed food samples, and was compared with First Derivative Spectrophotometry (FDS). The dyes Brilliant Blue (B), Sunset Yellow (S) and Tartrazine (T), which are common food additives, were employed for the comparisons. Polyester-type Polyurethane (PU) foam was used for extraction of the dyes from a solution containing the food matrix. For the spectrophotometric determinations, the adsorbed dyes were recovered by using dimethylformamide. The PAS measurements were carried out directly on the PU foam. The PAS method showed greater sensitivity, with detection limits of 0.028 mg L(-1) and 0.086 mg L(-1) for S and T, respectively, in the S+T mixture, and of 0.012 mg L(-1) and 0.068 mg L(-1) for B and T, respectively, in the B+T mixture. The values of relative error obtained for all the dyes were small: approximately 0.3-3.6% for the spectrophotometer, and approximately 0.1-2.9% for the PAS method. The PAS technique can be applied to the determination of the selected dyes in commercial food products, with some advantages: it reduces the number of analysis steps, it is a "green" method with less chemical waste, a minimal sample amount is needed, and it is non-destructive.


Assuntos
Análise de Alimentos/métodos , Corantes de Alimentos/análise , Espectrofotometria/métodos , Calibragem , Distribuição Normal
8.
J Phys Condens Matter ; 22(5): 055601, 2010 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-21386346

RESUMO

The optical, magnetic and structural properties of Eu doped low silica calcium aluminosilicate glasses were investigated. The optical absorption coefficient presented two bands at 39,246 and 29,416 cm(-1), which were assigned respectively to the [Formula in text], and [Formula in text] transitions of Eu(2+). The fluorescence measured at 300 K on a sample doped with 0.5 wt% of Eu(2)O(3) exhibited a broad band centered at 17,350 cm(-1), which is attributed to the [Formula in text] transition of Eu(2+), whereas the additional peaks are due to the [Formula in text] transitions of Eu(3+). From magnetization and XANES data it was possible to evaluate the fractions of Eu(2+) and Eu(3+) for the sample doped with 0.5 and 5.0 wt% of Eu(2)O(3), the values of which were approximately 30 and 70%, respectively.

9.
Opt Express ; 16(26): 21248-55, 2008 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-19104555

RESUMO

In this work the time resolved thermal lens method is combined with interferometric technique, the thermal relaxation calorimetry, photoluminescence and lifetime measurements to determine the thermo physical properties of Nd(2)O(3) doped sodium zincborate glass as a function of temperature up to the glass transition region. Thermal diffusivity, thermal conductivity, fluorescence quantum efficiency, linear thermal expansion coefficient and thermal coefficient of electronic polarizability were determined. In conclusion, the results showed the ability of thermal lens and interferometric methods to perform measurements very close to the phase transition region. These techniques provide absolute values for the measured physical quantities and are advantageous when low scan rates are required.

10.
Phys Rev Lett ; 100(2): 027402, 2008 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-18232921

RESUMO

This Letter reports the formation of Ti3+ in OH- free aluminosilicate glass melted under vacuum condition, with a very long lifetime (170 micros) and broad emission band shifted towards the visible region. This lifetime value was attributed to the trapping of the excited electrons by the glass defects and detrapping by thermal energy, and it is 2 orders of magnitude higher than those published for Ti3+ doped materials. Our results suggest that this glass is a promising system to overcome the challenge of extending the spectral range of traditional tunable solid state lasers towards the visible region.

11.
Appl Radiat Isot ; 65(5): 605-9, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17349796

RESUMO

Natural oxidation is an undesirable process suffered by gel dosimetry systems as it changes the values and spatial distribution of absorbed doses. Natural oxidation of Fricke xylenol gel (FXG) dosimeter was inferred from optical absorbance values measured for the first time using the photoacoustic technique. An acoustic detector measures the intensity of the light transmitted by the FXG, which is directly proportional to the ionizing radiation dose absorbed by the samples. In this work, we demonstrated the behavior, the rates, and the dependence of natural oxidation on storage temperature, time, and active components through measurements by photoacoustic technique.


Assuntos
Radiometria/instrumentação , Xilenos/química , Acústica , Géis/química , Oxirredução
12.
Appl Spectrosc ; 59(2): 173-80, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15720757

RESUMO

This work presents an add-on result of cross-linking using photoacoustic spectroscopy (PAS) phases in a multivariable process using the phase-resolved photoacoustic (PRPA) method. The method is tested to separate contributions from groupings -OH, -CH(2)-, -CH(3), and Si-OH overtones in the range from 700 to 2600 nm. Samples of the copolymers ethylene vinyltrimethoxysilane (EVS) and grafted vinyltrimethoxysilane (VTS) on low-density polyethylene (LDPE) were prepared having concentrations (C) of 3, 5, and 7% of catalyst and temperatures (T) of 70, 80, and 90 degrees C. By considering the condensation reaction, the reduction of -OH groups is monitored. The PRPA analysis was carried out using the surface response methodology and results indicated the optimum point for both answers (signal and phase-resolved) and for both factors of interest (C, T). For the copolymers, it was found that C approximately (5.00 +/- 1.14)% and T approximately (82.4 +/- 4.3) degrees C, while for grafted LDPE PE(g) it was found that C approximately (4.92 +/- 0.85)% and T approximately (80.8 +/- 2.5) degrees C. These results agreed with the chemical analysis for gel content, which showed as the optimum point 5% of catalyst and temperature of 80 degrees C. Further, it is an advantage that the photoacoustic method allows one to per- form a nondestructive analysis.


Assuntos
Algoritmos , Técnicas de Química Combinatória , Reagentes de Ligações Cruzadas/química , Análise Multivariada , Polímeros/química , Projetos de Pesquisa , Análise Espectral/métodos , Acústica , Reagentes de Ligações Cruzadas/análise , Interpretação Estatística de Dados , Análise Fatorial , Lasers , Polímeros/análise , Análise de Componente Principal , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
13.
Artigo em Inglês | MEDLINE | ID: mdl-11031592

RESUMO

This work demonstrates the occurrence of dn/dT inversion from negative to positive near the nematic-isotropic phase transition in a lyotropic liquid crystal. It is suggested that this effect can be attributed to a sudden increase of the electronic polarizability due to a change in the micelle shape near this phase transition. Formation of a long lasting lenslike element within the sample when it is irradiated at moderately high laser powers is also reported. This permanent lens is erasable by increasing the temperature above the nematic-isotropic transition temperature.


Assuntos
Cristalização , Conformação Molecular , Refratometria , Ácidos Láuricos , Modelos Biológicos , Água
14.
Br J Pharmacol ; 123(3): 435-42, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9504384

RESUMO

1. The effect of Tityus serrulatus scorpion venom and its toxin components on the rabbit isolated corpus cavernosum was investigated by use of a bioassay cascade. 2. Tityus serrulatus venom (3-100 microg), acetylcholine (ACh; 0.3-30 nmol) and glyceryl trinitrate (GTN; 0.5-10 nmol) dose-dependently relaxed rabbit isolated corpus cavernosum preparations precontracted with noradrenaline (3 microM). The selective soluble guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo [4,3,-alquinoxalin-1-one] (ODQ; 30 microM) increased the basal tone of the rabbit isolated corpus cavernosum and abolished the relaxations induced by the agents mentioned above. Methylene blue (30 microM) also inhibited the relaxations induced by Tityus serrulatus venom but, in contrast to ODQ, the inhibition was irreversible. 3. The non-selective NO synthase (NOS) inhibitors Nomega-nitro-L-arginine methyl ester (L-NAME; 10 microM) and NG-iminoethyl-L-ornithine (L-NIO; 30 microM) also increased the tone of the rabbit isolated corpus cavernosum and markedly reduced both ACh- and Tityus serrulatus venom-induced relaxations without affecting those evoked by GTN. The inhibitory effect was reversed by infusion of L-arginine (300 microM), but not D-arginine (300 microM). The neuronal NOS inhibitor 1-(2-trifluoromethylphenyl) imidazole (TRIM, 100 microM) did not affect either the tone of the rabbit isolated corpus cavernosum or the relaxations induced by ACh, bradykinin (Bk), Tityus serrulatus venom and GTN. TRIM was approximately 1,000 times less potent than L-NAME in inhibiting rabbit cerebellar NOS in vitro, as measured by the conversion of [3H]-L-arginine to [3H]-L-citrulline. 4. The protease inhibitor aprotinin (Trasylol; 10 microg ml[-1]) and the bradykinin B2 receptor antagonist Hoe 140 (D-Arg-[Hyp3,Thi5,D-Tic7, Oic8]-BK; 50 nM) did not affect the rabbit isolated corpus cavernosum relaxations induced by Tityus serrulatus venom. The ATP-dependent K+ channel antagonist glibenclamide (10 microm) and the Ca2+-activated K+ channel antagonists apamin (0.1 microM) and charybdotoxin (0.1 microM) also failed to affect the venom-induced relaxations. Similarly, the K+ channel blocker tetraethylammonium (TEA; 10 microM) had no effect on the venom-induced relaxations. 5. Capsaicin (3 and 10 nmol) relaxed the rabbit isolated corpus cavernosum in a dose-dependent and non-tachyphylactic manner. Ruthenium red (30 microM), an inhibitor of capsaicin-induced responses, markedly reduced the relaxations caused by capsaicin, but failed to affect those induced by Tityus serrulatus venom. L-NAME (10 microM) had no effect on the capsaicin-induced relaxations of the rabbit isolated corpus cavernosum. 6. The sodium channel blocker tetrodotoxin (TTX; 1 microM) abolished the relaxations of the rabbit isolated corpus cavernosum induced by Tityus serrulatus venom without affecting those evoked by capsaicin, ACh and GTN. Tetrodotoxin (1 microM) also promptly reversed the response to the venom when infused during the relaxation phase. 7. The bioassay cascade of the toxin components purified from Tityus serrulatus venom revealed that only fractions X, XI and XII caused dose-dependent relaxations of the rabbit isolated corpus cavernosum and these were markedly reduced by either TTX (1 microM) or L-NAME (10 microM). 8. Our results indicate that Tityus serrulatus scorpion venom (and the active fractions X, XI and XII) relaxes rabbit corpus cavernosum via the release of NO. This release is specifically triggered by the activation of capsaicin-insensitive cavernosal non-adrenergic non-cholinergic (NANC) fibres, that may possibly be nitrergic neurones. Tityus serrulatus venom may therefore provide an important tool for understanding further the mechanism of NANC nitrergic nerve activation.


Assuntos
Óxido Nítrico/fisiologia , Pênis/efeitos dos fármacos , Venenos de Escorpião/farmacologia , Animais , Aprotinina/farmacologia , Atropina/farmacologia , Bradicinina/análogos & derivados , Bradicinina/farmacologia , Inibidores Enzimáticos/farmacologia , Técnicas In Vitro , Masculino , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Pênis/inervação , Pênis/metabolismo , Bloqueadores dos Canais de Potássio , Coelhos , Receptores Adrenérgicos/metabolismo , Receptores Colinérgicos/metabolismo , Bloqueadores dos Canais de Sódio , Tetrodotoxina/farmacologia
15.
Toxicon ; 34(10): 1141-7, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8931254

RESUMO

The venom of the Brazilian spider Phoneutria nigriventer was fractionated using a C18 microBondapack reverse-phase high-performance liquid chromatography column. The resulting fractions were assayed in the rabbit perfused corpus cavernosum tissue to identify those fractions responsible for the corpus cavernosum relaxation. Two fractions (A and B) with retention times of 18.1 and 36.7 min, respectively, induced relaxation of corpus cavernosum strips. Fraction A was selected for further biochemical characterization. Repurification of this fraction revealed the presence of a polypeptide (named PNV4) which migrates in sodium dodecyl sulphate-polyacrylamide gel electrophoresis as a single band consistent with a mol. wt close to 16,600. The amino acid composition of PNV4 showed the presence of 147 residues, a high content of Cys and a calculated mol. wt of 17,213 + Trp. The N-terminal amino acid sequence of PNV4 determined for its first 48 residues was AELTSCFPVGHECDGDASNCNCCGDDVYCGCGWGRWNCKCKVADQSYA.


Assuntos
Pênis/efeitos dos fármacos , Peptídeos/isolamento & purificação , Venenos de Aranha/isolamento & purificação , Sequência de Aminoácidos , Animais , Masculino , Dados de Sequência Molecular , Peptídeos/farmacologia , Coelhos , Venenos de Aranha/química , Venenos de Aranha/farmacologia
16.
Basic Res Cardiol ; 91(3): 248-55, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8831944

RESUMO

We have compared the myocardial alterations in rats made hypertensive by the chronic inhibition of nitric oxide biosynthesis with those having renal hypertension (two kidney-one clip model). Male Wistar rats were chronically administered the nitric oxide synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) for 2, 4 and 8 weeks. Both groups initially developed a similar increase in blood pressure but only the 2K-1C rats developed myocardial hypertrophy after 2-4 weeks. L-NAME-treated animals developed a similar degree of hypertrophy following 8 weeks of treatment. As observed by light microscopy, the myocardial alterations in the latter animals consisted of extensive areas of fibrosis and myocardial necrosis, especially in regions of the subendocardium. The histological alterations induced by L-NAME were not caused by the accompanying hypertension, since the 2K-1C animals had a similar increase in arterial blood pressure without any significant alterations in the heart morphology. 2K-1C rats treated chronically with L-NAME behaved in a manner similar to the L-NAME-treated animals with regard to both the blood pressure increases and cardiac morphological alterations. Animals which received the inactive enantiomer D-NAME did not develop hypertension nor did they have any morphological abnormalities. Both the coronary flow and the contractile capacity of hearts isolated from rats treated with L-NAME for 8 weeks were impaired compared to control animals. These results indicate that the chronic inhibition of NO biosynthesis causes cardiac ischemia associated with a mechanical dysfunction that is unrelated to cardiac hypertrophy which is similar to those seen in some patients suffering from chronic arterial hypertension.


Assuntos
Cardiomegalia/etiologia , Inibidores Enzimáticos/farmacologia , Isquemia Miocárdica/etiologia , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico/antagonistas & inibidores , Análise de Variância , Animais , Cardiomegalia/patologia , Cardiomegalia/fisiopatologia , Modelos Animais de Doenças , Hemodinâmica/efeitos dos fármacos , Hipertensão/etiologia , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Masculino , Isquemia Miocárdica/patologia , Isquemia Miocárdica/fisiopatologia , Óxido Nítrico/biossíntese , Tamanho do Órgão , Ratos , Ratos Wistar
17.
Toxicon ; 33(2): 171-8, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7597720

RESUMO

Fractionation of Phoneutria nigriventer venom by Sephadex G-10 followed by ion-exchange chromatography yields a fraction (fraction XIII) which increases microvascular permeability in rabbit skin in vivo by activating the tissue kallikrein-kinin system. One polypeptide (PNV3) with the ability to increase microvascular permeability in the rabbit skin in vivo was isolated from fraction XIII and biochemically characterized. PNV3 has 132 amino acid residues with a calculated mol. wt of 14,475. This polypeptide showed the following N-terminal sequence: AVFAIQDQPC. Amino acid analysis indicated the presence of six disulfide bridges and a high content of Glx (20%). Pairwise comparison of PNV3 amino acid sequence with 27 other spider venom polypeptides and proteins indicated that PNV3 presents high similarity (60-70%) with other toxins (Tx2.1, Tx2.5 and Tx2.6) isolated from P. nigriventer venom.


Assuntos
Peptídeos/isolamento & purificação , Pele/irrigação sanguínea , Venenos de Aranha/química , Venenos de Aranha/toxicidade , Sequência de Aminoácidos , Aminoácidos/análise , Animais , Permeabilidade Capilar/efeitos dos fármacos , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Eletroforese em Gel de Poliacrilamida , Dados de Sequência Molecular , Peso Molecular , Peptídeo Hidrolases/metabolismo , Coelhos , Venenos de Aranha/enzimologia
18.
Biochem Pharmacol ; 46(6): 1092-5, 1993 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-8216354

RESUMO

The fractionation of Phoneutria nigriventer spider venom by gel filtration (Sephadex G-10-120) followed by ion-exchange chromatography (microgranular CM-cellulose-52) resulted in sixteen fractions (CI to CXVI) from which CVII+VIII, CIX and CX+XI caused dose-dependent and short-lived contractions of both arterial and venous rabbit vessels. Fraction CX+XI was further purified by a reverse phase HPLC, and a contractile polypeptide (PNV2) was isolated. The amino terminal sequence of PNV2 (LAKRADICQPGKTSQRACET) indicated that it represents a pure polypeptide consisting of a single chain. Furthermore, the amino acid analysis of PNV2 revealed the presence of four disulfide bridges, a high content in Lys (14%), Glx (11%), and the absence of His. The global amino acid composition showed that this polypeptide is composed of 102 residues (Trp not included) with a calculated molecular weight of 12,114. Whether this peptide is responsible for the vascular alterations observed in Phoneutria envenomation, such as lung edema and priapism, remains to be further investigated.


Assuntos
Músculo Liso Vascular/efeitos dos fármacos , Neuropeptídeos/isolamento & purificação , Peptídeos/isolamento & purificação , Venenos de Aranha/química , Venenos de Aranha/isolamento & purificação , Sequência de Aminoácidos , Animais , Peptídeos e Proteínas de Sinalização Intercelular , Masculino , Dados de Sequência Molecular , Contração Muscular/efeitos dos fármacos , Neuropeptídeos/química , Neuropeptídeos/farmacologia , Peptídeos/química , Peptídeos/farmacologia , Coelhos , Venenos de Aranha/farmacologia
19.
Gen Pharmacol ; 23(3): 565-70, 1992 May.
Artigo em Inglês | MEDLINE | ID: mdl-1324871

RESUMO

1. Estrogen pretreatment increases the responsiveness to noradrenaline and to clonidine in isolated rat female aortae. 2. Determinations of the pKA and pA2 of noradrenaline and prazosin, respectively suggest that the isolated female aorta possess a homogeneous alpha 1-adrenoceptor population. 3. The fast and slow components of clonidine-induced aorta contraction were determined using nifedipine. 4. Considering that after estrogen pretreatment, an increase in spare alpha 1-adrenoceptors probably occur and only the fast component of clonidine-induced contraction was enhanced we concluded that estrogen pretreatment increases the number of alpha 1-adrenoceptors and the amount of intracellular calcium available for contraction.


Assuntos
Estrogênios/farmacologia , Músculo Liso Vascular/efeitos dos fármacos , Receptores Adrenérgicos alfa/efeitos dos fármacos , Animais , Aorta Torácica/efeitos dos fármacos , Clonidina/farmacologia , Feminino , Contração Muscular/efeitos dos fármacos , Norepinefrina/farmacologia , Prazosina/farmacologia , Gravidez , Ratos , Ratos Endogâmicos
20.
J Cardiovasc Pharmacol ; 11(4): 473-7, 1988 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-2453752

RESUMO

We studied the role played by postjunctional adrenoceptors in the vasoconstrictor responses of perfused tail arteries of young prehypertensive (4-6 weeks old) and adult (14-16 weeks) spontaneously hypertensive rats (SHR) with norepinephrine (NE), phenylephrine and epinephrine. Age-matched Wistar normotensive rats (WNR) were also used. In tail artery of young SHR, as well as in age-matched WNR and adult WNR, responsiveness to the vasoconstrictor agents did not differ. Determination of KB values of prazosin using phenylephrine and epinephrine as agonists and analysis of Schild plots indicate that responsiveness to the vasoconstrictor agents in young SHR tail artery is mediated by alpha 1-adrenoceptors. Tail arteries of adult SHR were more responsive to epinephrine than were tail arteries of age-matched WNR. In tail arteries of adult SHR, the KB value of prazosin against epinephrine remains undetermined since the slope of the Schild plot statistically differs from 1.0 (0.32). These results strongly suggest that in perfused tail arteries of adult SHR, responses to epinephrine are also mediated by alpha 2-adrenoceptors. We postulate an important but unknown role for the interaction between epinephrine and postjunctional alpha 2-adrenoceptors in the development and maintenance of genetically-induced hypertension.


Assuntos
Epinefrina/farmacologia , Hipertensão/fisiopatologia , Receptores Adrenérgicos alfa/fisiologia , Animais , Artérias/efeitos dos fármacos , Artérias/fisiopatologia , Masculino , Norepinefrina/farmacologia , Fenilefrina/farmacologia , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Cauda/irrigação sanguínea , Vasoconstrição
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