Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
1.
Org Biomol Chem ; 22(20): 4123-4134, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38700442

RESUMO

A family of stilbenyl-azopyrroles compounds 2a-d and 3a-d was efficiently obtained via a Mizoroki-Heck C-C-type coupling reaction between 2-(4'-iodophenyl-azo)-N-methyl pyrrole (1a) and different vinyl precursors. The influence of the π-conjugated backbone and the effect of the pyrrole moiety were correlated with their optical properties. Studies via UV-Visible spectrophotometry revealed that the inclusion of EWG or EDG favors a red-shift of the main absorption band in these azo compounds compared with their non-substituted analogues. Furthermore, there is a clear influence between the half-life of the Z isomer formed by irradiation with white light and the push-pull behavior of the molecules. In several cases, the stilbenyl-azopyrroles led to the formation of J-type aggregates in binary MeOH : H2O solvents, which are of interest for water compatible applications.

2.
Environ Pollut ; 331(Pt 1): 121936, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37263563

RESUMO

Although aluminum is widely distributed in the earth's crust, its environmental availability and wildlife assimilation rates are only partially known. Here we analyze aluminum concentrations in bone from 10 species of marine mammals inhabiting 3 geographic areas subject to different aluminum inputs: the Río de la Plata estuary (Uruguay), the coastal waters of Mauritania and the Galapagos archipelago (Ecuador). Overall, concentrations were unusually high as compared to those of terrestrial animals, with lowest concentrations in the Galapagos archipelago, then the Río de la Plata estuary and finally Mauritania. The aluminum source varied between regions, prevailing anthropogenic sources in the Río de la Plata Estuary and natural sources (wind-blown dust) in Mauritanian waters. The type of source determined contamination levels: anthropogenic sources were most significant for coastal species and showed a decline with distance of habitat from shoreline, while natural sources had a higher influence on open waters because of the dearth of biogenic silica that eliminates aluminum from the water column. Since aluminum remains in bone for several decades, marine mammal bone reflects historical levels of aluminum and therefore is a good bioindicator of the aluminum concentration of the marine environment.


Assuntos
Alumínio , Ecossistema , Animais , Uruguai , Estuários , Mamíferos , Monitoramento Ambiental
3.
Org Biomol Chem ; 18(8): 1657-1670, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32048680

RESUMO

A new family of push-pull biphenyl-azopyrrole compounds 3b-g and 4b-d was efficiently obtained via a Suzuki cross-coupling reaction between 2-(4'-iodophenyl-azo)-N-methyl pyrrole (1a) or 3-(4'-iodophenyl-azo)-1,2,5-trimethyl pyrrole (2a) and 4'-substituted phenyl boronic acids in excellent yields. The influence of the π-biphenyl backbone and pyrrole pattern substitution was correlated with their optical properties. Solvatochromic studies via UV-visible spectrophotometry revealed that the inclusion of a 4'-nitro-biphenyl fragment favors a red-shift of the main absorption band in these azo compounds compared with their non-substituted analogues. Likewise, optical band-gaps were estimated by means of electronic absorption spectra and correlated with TD-DFT studies. The pyrrole pattern substitution and the π-conjugated backbone exhibit a clear influence on their thermal isomerization kinetics at room temperature. In all cases, biphenylazo-pyrrole compounds lead to the formation of J-type aggregates in binary MeOH : H2O solvents. Under these conditions, compounds 3b-c undergo a water-assisted cis-to-trans isomerization at room temperature.

4.
Phys Rev B ; 100(9)2019.
Artigo em Inglês | MEDLINE | ID: mdl-33553858

RESUMO

We have measured the room-temperature phonon spectrum of Mo-stabilized γ-U. The dispersion curves show unusual softening near the H point, q = [1/2, 1/2, 1/2], which may derive from the metastability of the γ-U phase or from strong electron-phonon coupling. Near the zone center, the dispersion curves agree well with theory, though significant differences are observed away from the zone center. The experimental phonon density of states is shifted to higher energy compared to theory and high-temperature neutron scattering. The elastic constants of γ-UMo are similar to those of body-centered cubic elemental metals.

5.
J Chem Ecol ; 44(11): 1058-1067, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30191434

RESUMO

Floral scents attract pollinators to plant rewards; in nectarless flowers, pollen grains are the only reward. Thus, pollen not only fertilizes ovules, but also feeds pollinators. This dilemma is resolved by specialization of anthers (i.e., heteranthery): feeding anthers that feed pollinators and pollinating anthers for fertilization. We hypothesized that the chemical composition of floral volatiles differs between the two types of anther and influences pollination preference for feeding anthers. We used Solanum rostratum as a study model because its heterantherous flowers produce a floral scent that suggests a close association with their pollinators. The main aim of this study was to determine the chemical composition of the two types of anther and to investigate how they influence foraging behaviour of pollinators. To characterize this composition, we used solid phase microextraction and hexane extraction followed by gas chromatography-mass spectrometry. We registered 12 volatile compounds in S. rostratum floral extracts, mainly aromatic and sesquiterpene compounds. The proportion of these compounds differed between feeding and pollinating anthers. Some of these compounds were probably emitted by osmophores located in both anther types. Also, we used electroantennography to investigate Melipona solani antennal response to floral volatiles. The M. solani antennae are receptive to the highest floral extract dose tested. Finally, we conducted two behavioural bioassays to test bee attraction for each type of floral extract: a) multiple-choice in a feeding arena using M. solani and b) Y-olfactometer bioassay using Bombus impatiens. Both bee species preferred feeding anthers in bioassays. In conclusion, heteranthery involves chemical differentiation (i.e., proportion of volatiles compounds) in anther specialization that influences bee preference for feeding anthers over pollinating anthers.


Assuntos
Pólen/química , Solanum/química , Compostos Orgânicos Voláteis/análise , Animais , Antenas de Artrópodes/efeitos dos fármacos , Antenas de Artrópodes/fisiologia , Abelhas/fisiologia , Comportamento Animal/efeitos dos fármacos , Flores/química , Flores/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Pólen/metabolismo , Solanum/metabolismo , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/isolamento & purificação , Compostos Orgânicos Voláteis/farmacologia
6.
Med. U.P.B ; 36(1): 80-83, ene.-jun. 2017.
Artigo em Espanhol | LILACS, COLNAL | ID: biblio-837137

RESUMO

La intoxicación por amitraz es poco frecuente en Colombia. Los objetivos de este reporte de caso son evidenciar una presentación atípica de la intoxicación en un paciente de edad avanzada y resaltar aspectos toxico-cinéticos y toxico-dinámicos asociados. La literatura consiste, principalmente, en reportes de caso y series de casos y en Norteamérica. Existe la necesidad de que el personal de salud involucrado en el manejo de estos pacientes reconozca aspectos clave de su fisiopatología y tratamiento. El caso reportado es de un paciente masculino de 73 años, intoxicado por amitraz, que se presenta inicialmente sin alteraciones, y luego de 33 horas, presenta alteraciones del sensorio y compromiso respiratorio, por lo que requiere una disposición en Unidad de Cuidados Especiales (UCE). El paciente tiene evolución satisfactoria.


Amitraz poisoning is not frequent in Colombia. The objectives of this case report are to consider the atypical poisoning in an elderly patient and to emphasize the associated toxic-kinetic and toxic-dynamic aspects. The literature mainly consists of case reports and case series in North America. There is a need for the health personnel involved in the treatment of these patients to recognize key aspects of its physiopathology and treatment. The case reported involves a male patient aged 73 with amitraz poisoning, initially without alterations after 33 hours, presenting sensory alterations and respiratory compromise requiring attention in the Special Care Unit (SCU). The patient recovered satisfactorily.


A intoxicação por Amitraze é pouco frequente na Colômbia. Os objetivos deste relato de caso são evidenciar uma apresentação atípica da intoxicação num paciente de idade avançada e ressaltar aspectos toxico-cinéticos e toxico-dinâmicos associados. A literatura consiste, principalmente, em relato de caso e séries de casos e na América do Norte. Existe a necessidade de que o pessoal da saúde envolvido no manejo destes pacientes reconheça aspectos chave da sua fisiopatologia e tratamento. O caso reportado é de um paciente masculino de 73 anos, intoxicado por amitraz, que se apresenta inicialmente sem alterações, e logo de 33 horas, apresenta alterações do sensório e compromisso respiratório, pelo qual requere uma disposição em Unidade de Cuidados Especiais (UCE). O paciente tem evolução satisfatória.


Assuntos
Humanos , Animais , Inseticidas , Intoxicação , Terapêutica
7.
Allergol. immunopatol ; 42(6): 580-585, nov.-dic. 2014.
Artigo em Inglês | IBECS | ID: ibc-130149

RESUMO

BACKGROUND: There are two inheritance patterns, the X-linked recessive (XL) pattern and the autosomal recessive pattern. There is no information on the predominant inheritance pattern of male patients with chronic granulomatous disease (CGD) in Mexico. OBJECTIVE: The aim of this study was to determine the inheritance pattern in a cohort of Mexican male patients with CGD by means of the detection of an XL status carrier among their female relatives, and to describe the frequency of discoid lupus (DL) among carriers. METHODS: We detected the female relatives within the families of male patients with CGD, and carried out the 123 dihydrorhodamine (DHR) assay in all female participants. All carriers were questioned for current or past established DL diagnosis. RESULTS: We detected 33 families with one or more CGD male patients; we found an XL-CGD in 79% of the relatives from at least one female relative with a bimodal pattern. For the remaining seven relatives we were not able to confirm a carrier status by means of a DHR assay. Moreover, we detected one mother with CGD secondary to skewed X-chromosome inactivation. We also found 47 carriers, and only one carrier with DL among them. CONCLUSION: We concluded that XL-CGD is the most frequent form of CGD in a cohort of CGD male patients in Mexico. DHR assay is a fast and practical tool to determine the CGD form in the Latin-American countries. Finally, DL frequency in Mexico is lower than that reported in the literature for other regions of the world


No disponible


Assuntos
Humanos , Doença Granulomatosa Crônica/genética , Lúpus Eritematoso Discoide/epidemiologia , Portador Sadio , México/epidemiologia , Marcadores Genéticos
8.
Allergol Immunopathol (Madr) ; 42(6): 580-5, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24890515

RESUMO

BACKGROUND: There are two inheritance patterns, the X-linked recessive (XL) pattern and the autosomal recessive pattern. There is no information on the predominant inheritance pattern of male patients with chronic granulomatous disease (CGD) in Mexico. OBJECTIVE: The aim of this study was to determine the inheritance pattern in a cohort of Mexican male patients with CGD by means of the detection of an XL status carrier among their female relatives, and to describe the frequency of discoid lupus (DL) among carriers. METHODS: We detected the female relatives within the families of male patients with CGD, and carried out the 123 dihydrorhodamine (DHR) assay in all female participants. All carriers were questioned for current or past established DL diagnosis. RESULTS: We detected 33 families with one or more CGD male patients; we found an XL-CGD in 79% of the relatives from at least one female relative with a bimodal pattern. For the remaining seven relatives we were not able to confirm a carrier status by means of a DHR assay. Moreover, we detected one mother with CGD secondary to skewed X-chromosome inactivation. We also found 47 carriers, and only one carrier with DL among them. CONCLUSION: We concluded that XL-CGD is the most frequent form of CGD in a cohort of CGD male patients in Mexico. DHR assay is a fast and practical tool to determine the CGD form in the Latin-American countries. Finally, DL frequency in Mexico is lower than that reported in the literature for other regions of the world.


Assuntos
Cromossomos Humanos X/genética , Doença Granulomatosa Crônica/genética , Padrões de Herança , Lúpus Eritematoso Discoide/genética , Rodaminas , Separação Celular , Estudos de Coortes , Feminino , Citometria de Fluxo/métodos , Testes Genéticos , Doença Granulomatosa Crônica/diagnóstico , Heterozigoto , Humanos , Padrões de Herança/genética , Lúpus Eritematoso Discoide/diagnóstico , Masculino , México , Linhagem
9.
Bioing fís med cuba ; 6(1)ene.-abr.2005. tab, graf
Artigo em Espanhol | CUMED | ID: cum-26807

RESUMO

El dolor ha sido considerado un aspecto dentro de los sìntomas más comunes dentro de las laceraciones de la mucosa oral. El tratamiento aplicado en estos va dirigido fundamentalmente a la dismunución de esta sintomatología. Numerosos han sido los métodos para lograr este propósito, que van desde los ácidos que cauterizan la lesión, hasta sustancias protectoras y cicatrizantes. El trabajo tiene como objetivo mostrar los resultados clínicos de la aplicación de un cianocrilato de n-butilo (Tisuacryl)en la disminución de las molestias dolorosas en lesiones de la mucosa oral producidas por diferentes causas. El producto se ha evaluado en esta aplicación desde 1998 en 25 pacientes, sin restringir edad o sexo que acudieron a los servicios estomatológicos de la Empresa Aerogaviota y la clìnica estomatológica Docente de Bauta con lesiones o laceraciones de la mucosa oral de cualquier localización, dimensión y etiología. Los resultados demuestran que el tratamiento con Tisuacryl disminuye el dolor en los casos de lesiones de mucosa oral, permitiendo al paciente la ingestión inmediata de alimentos(AU)


Assuntos
Lacerações , Mucosa Bucal , Analgésicos
10.
Med Biol Eng Comput ; 39(4): 428-33, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11523731

RESUMO

Cross-correlation between cerebral blood flow (CBF) and background EEG activity can indicate the integrity of CBF control under changing metabolic demand. The difficulty of obtaining long, continuous recordings of good quality for both EEG and CBF signals in a clinical setting is overcome, in the present work, by an algorithm that allows the cross-correlation function (CCF) to be estimated when the signals are interrupted by segments of missing data. Methods are also presented to test the statistical significance of the CCF obtained in this way and to estimate the power of this test, both based on Monte Carlo simulations. The techniques are applied to the time-series given by the mean CBF velocity (recorded by transcranial Doppler) and the mean power of the EEG signal, obtained in 1 s intervals from nine sleeping neonates. The peak of the CCF is found to be low (< or = 0.35), but reached statistical significance (p < 0.05) in five of the nine subjects. The CCF further indicates a delay of 4-6s between changes in EEG and CBF velocity. The proposed signal-analysis methods prove effective and convenient and can be of wide use in dealing with the common problem of missing samples in biological signals.


Assuntos
Circulação Cerebrovascular/fisiologia , Eletroencefalografia , Processamento de Sinais Assistido por Computador , Velocidade do Fluxo Sanguíneo/fisiologia , Humanos , Recém-Nascido , Método de Monte Carlo , Ultrassonografia Doppler Transcraniana
11.
Invest Ophthalmol Vis Sci ; 35(8): 3134-44, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8045708

RESUMO

PURPOSE: To characterize the pedigree, visual function phenotype, and responsible mutation in a large family with autosomal dominant retinitis pigmentosa. METHODS: Pedigree data were obtained by personal interviews and corroborated with community records. One hundred twenty-eight members of the family were examined clinically, and a subset of 12 affected subjects was further studied with dark- and light-adapted static perimetry and electroretinography. The coding region of the rhodopsin gene was polymerase chain reaction (PCR) amplified and resolved by denaturing gradient gel electrophoresis. Genomic DNA samples from nine affected and five unaffected family members were analyzed by PCR amplification and restriction enzyme digestion. RESULTS: A 14-generation pedigree was identified in which retinitis pigmentosa (RP) was inherited in an autosomal dominant fashion. Affected individuals reported early night blindness and showed vessel attenuation and bone spicule-like pigmentary changes. In these individuals, the rod electroretinogram (ERG) was not detectable, and the cone ERG was reduced in amplitude and delayed in timing. With dark-adapted perimetry, rod function could be detected in only one young patient, and it was markedly abnormal. Light-adapted perimetry indicated that cone sensitivity could be relatively well preserved in the central field, but it was diminished in the periphery even in the most mildly affected subjects. A valine345-to-leucine mutation was identified in the rhodopsin gene and shown to cosegregate in the heterozygous condition with the disease. CONCLUSIONS: The natural history of RP in this family begins with a loss of rod function, progresses to involve the cone system, and leads eventually to a severe loss of visual function. The invariance of valine345 in all functional vertebrate visual pigments sequenced to date, and the unusually conservative nature of the valine345-to-leucine mutation suggests that the carboxy terminus of rhodopsin is involved in a highly specific interaction with one or more rod proteins.


Assuntos
Retinose Pigmentar/genética , Adolescente , Adulto , Idoso , Sequência de Aminoácidos , Análise Mutacional de DNA , Adaptação à Escuridão , Eletrorretinografia , Feminino , Humanos , Leucina/genética , Masculino , Dados de Sequência Molecular , Linhagem , Células Fotorreceptoras/fisiologia , Reação em Cadeia da Polimerase , Retinose Pigmentar/fisiopatologia , Rodopsina/genética , Valina/genética , Testes de Campo Visual
12.
J Virol ; 68(4): 2662-70, 1994 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8139043

RESUMO

To assess the influence of the 3' long terminal repeat (LTR) on the promoter/enhancer activity of the 5' LTR, a set of isogenic retroviral vectors differing only in the U3 region of the 3' LTR was constructed. These U3 elements were derived from viruses with different tissue tropism. The 5' LTR originated from Moloney murine leukemia virus and directed the transcription of a reporter gene (chloramphenicol acetyltransferase [CAT] gene), giving rise to plasmids of the general configuration LTR-CAT-LTR'. Following transfection of these chimeric constructs into various cell types, the CAT activity in a given cell line was inversely related to the activity of the downstream U3 region when used in a single-LTR construct in that cell type, indicating negative regulation of the 5' LTR by the chimeric 3' LTR'. Our data indicate that a highly active 3' LTR interferes with gene expression from the 5' LTR. Potential mechanisms for this down-regulation are discussed.


Assuntos
Regulação Viral da Expressão Gênica , Vírus da Leucemia Murina de Moloney/genética , Provírus/genética , Sequências Repetitivas de Ácido Nucleico/genética , Animais , Linhagem Celular , Cloranfenicol O-Acetiltransferase/biossíntese , Cloranfenicol O-Acetiltransferase/genética , Regulação para Baixo , Vetores Genéticos/genética , Humanos , Camundongos , RNA Antissenso/análise , RNA Mensageiro/análise , Proteínas Recombinantes de Fusão/biossíntese , Transcrição Gênica , Transdução Genética , Integração Viral/genética
13.
Artigo em Inglês | MEDLINE | ID: mdl-2159992

RESUMO

This study was undertaken to calculate the in vivo drug interactions between recombinant human interferon-alpha A/D (rHuIFN-alpha A/D) and 3'-azido-3'-deoxythymidine (AZT) in a quantitative model for retroviral viremia. When given as single agents, both AZT and rHuIFN-alpha A/D suppressed virus-induced splenomegaly in a dose-dependent fashion in mice inoculated with Rauscher murine leukemia virus (RLV). However, suppressive doses of single-agent AZT caused anemia after 20 days of therapy. Combining rHuIFN-alpha A/D with AZT allowed drastic dose reductions for each agent while maintaining greater than or equal to 93% inhibition of splenomegaly. No clinically significant toxicity was seen. Computer analysis with the isobologram technique and combination index method showed that these combination regimens were highly synergistic. A 20-day course of AZT + rHuIFN-alpha A/D started 4 h after virus exposure was protective against RLV viremia and disease. After cessation of therapy, the animals were resistant to rechallenge with fully infectious RLV. We conclude that prompt initiation of effective combination therapy after retroviral exposure prevented viremia and disease and led to protective immunity.


Assuntos
Interferon Tipo I/uso terapêutico , Infecções por Retroviridae/tratamento farmacológico , Viremia/prevenção & controle , Zidovudina/uso terapêutico , Animais , Linhagem Celular , Sinergismo Farmacológico , Quimioterapia Combinada , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Vírus Rauscher/efeitos dos fármacos , Proteínas Recombinantes , Replicação Viral/efeitos dos fármacos
15.
Contraception ; 19(5): 489-95, 1979 May.
Artigo em Inglês | MEDLINE | ID: mdl-467056

RESUMO

A randomized, crossover study comparing the acceptability of two presentations of the same oral contraceptive, a paper formulation and the conventional tablet, was carried out among two-hundred-and-seventy women attending two urban family planning clinics in Mexico City. During the first three cycles of use, the percentage of women discontinuing the medication for side effects was almost identical in the two groups. Although the paper formulation failed to demonstrate any major advantage in terms of continuation or acceptability, it was preferred by a majority of the women who began oral contraception with its use.


Assuntos
Etinilestradiol/administração & dosagem , Norgestrel/administração & dosagem , Papel , Adolescente , Adulto , Envelhecimento , Anticoncepcionais Orais/efeitos adversos , Feminino , Humanos , México , Fatores Socioeconômicos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...