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1.
Rev. Fac. Med. UNAM ; 66(4): 20-25, jul.-ago. 2023. graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1514819

RESUMO

Resumen El síndrome de kwashiorkor se caracteriza por malnutrición proteica y edema generalizado; algunos de los factores de riesgo que se asocian a su aparición son: vivir en pobreza, el destete reciente, las infecciones y las dietas basadas en maíz y arroz. Este síndrome puede generar manifestaciones cutáneas como piel delgada y seca, hiperpigmentación, áreas confluentes de descamación, cabello seco, hipopigmentado y desprendible, así como una dermatitis erosiva con predominio en pliegues cutáneos. El diagnóstico se basa principalmente en una evaluación nutricional integral, exploración física y estudios de laboratorio, y el éxito del tratamiento se basa en la rehabilitación nutricional temprana. Caso clínico: lactante del sexo femenino de 8 meses de edad, que acudió al Instituto Nacional de Pediatría (INP), por presentar una dermatosis generalizada de tipo descamativa de 1 mes de evolución, que fue tratada con ketoconazol tópico. Al interrogatorio la madre refiere alimentación exclusiva con atole de maíz por un diagnóstico de "alergia a la leche" y falta de recursos económicos para comprar la fórmula hidrolizada. La paciente presentaba una dermatosis diseminada que afectaba todos los segmentos corporales, caracterizada por placas hiperpigmentadas, bien definidas, de forma irregular, con descamación en láminas gruesas en región perioral y extremidades, así como áreas erosionadas, pálidas y edema generalizado en extremidades. Se realizaron exámenes de laboratorio que mostraron que la paciente tenía anemia (Hb 11.2 g/dL) e hipoalbuminemia (3.3 g/dL) que, en conjunto con las manifestaciones clínicas, integraron el diagnóstico de síndrome de Kwashiorkor. Se informaron los hallazgos clínicos y de laboratorio al servicio de Gastroenterología y Nutrición, quienes realizaron una valoración nutricional integral y decidieron iniciar tratamiento nutricional; por parte del servicio de Dermatología, se indicó el uso de emolientes y cuidados generales de la piel. Veinte días después la dermatosis y el edema habían remitido.


Abstract Kwashiorkor syndrome is characterized by protein malnutrition and edema, risk factors are recent weaning, infections, and diets based on corn and rice. This malnutrition can lead to skin manifestations such as thin, dry skin, hyperpigmentation, confluent areas of scaling, dry, hypopigmented, and detachable hair, as well as erosive dermatitis, predominantly in skin folds. The diagnosis is based on a nutritional evaluation exam, physical examination and laboratory finding, the treatment is based on early nutritional rehabilitation. Clinical case: 8-month-old female infant who attended the Instituto Nacional de Pediatría, presenting a scaling dermatosis of 1 month's evolution that was treated with topical ketoconazole. The mother reported exclusive feeding with corn gruel due to the diagnosis of "lactose allergy" and commented not enough resources to buy hydrolyzed formula. The patient presented a disseminated dermatosis to all body segments, characterized by well-defined, irregularly shaped, hyperpigmented plaques with scaling in thick sheets in the perioral region and extremities, as well as areas of eroded skin and paleness and edema of extremities. Laboratory tests were taken, where anemia (Hb 11.2 g/dl) and hipoalbuminemia (3.3 g/dl) were documented, the diagnosis of kwashiorkor syndrome was integrated. The clinical and laboratory findings were reported to the Gastroenterology and Nutrition service, who performed a nutritional assessment, and began nutritional treatment, emollients and general skin care were documented; twenty days later, the dermatosis and edema had subsided.

2.
Vaccines (Basel) ; 10(2)2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-35214639

RESUMO

Global surveillance programs for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are showing the emergence of variants with mutations in the spike protein. Genomic and laboratory surveillance are important to determine if these variants may be more infectious or less susceptible to antiviral treatments and vaccine-induced antibodies. Three of the most predominant SARS-CoV-2 variants in Colombia during the epidemiological peaks of 2021 were isolated: Mu, a variant of interest; Gamma, a variant of concern; B.1.111, which lacks genetic markers associated with greater virulence. Microneutralization assays were performed by incubating 120 mean tissue culture infectious doses (TCID50) of each SARS-CoV-2 isolate with five two-fold serial dilutions of sera from 31 BNT162b2-vaccinated volunteers. The mean neutralization titer (MN50) was calculated by the Reed-Muench method. At the end of August, Mu represented 49% of coronavirus disease 2019 (COVID-19) cases in Colombia, followed by 25% of Gamma. In contrast, B.1.111 became almost undetectable. The evaluation of neutralizing antibodies suggests that patients vaccinated with BNT162b2 generate neutralizing antibody titers against the Mu variant at significantly lower concentrations relative to B.1.111 and Gamma. This study shows the importance of continuing surveillance programs of emerging variants, as well as the need to evaluate the neutralizing antibody response induced by other vaccines.

4.
Invest New Drugs ; 40(1): 30-41, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34478029

RESUMO

Breast cancer is the leading cause of cancer death among women worldwide. For this reason, the development of new therapies is still essential. In this work we have analyzed the antitumor potential of levoglucosenone, a chiral building block derived from the pyrolysis of cellulose-containing materials such as soybean hulls, and three structurally related analogues. Employing human and murine mammary cancer models, we have evaluated the effect of our compounds on cell viability through MTS assay, apoptosis induction by acridine orange/ethidium bromide staining and/or flow cytometry and the loss of mitochondrial potential by tetramethylrhodamine methyl ester staining. Autophagy and senescence induction were also evaluated by Western blot and ß-galactosidase activity respectively. Secreted metalloproteases activity was determined by quantitative zymography. Migratory capacity was assessed by wound healing assays while invasive potential was analyzed using Matrigel-coated transwell chambers. In vivo studies were also performed to evaluate subcutaneous tumor growth and experimental lung colonization. All compounds impaired in vitro proliferation with IC50 values in a range of low micromolar. Apoptosis was identified as the main mechanism responsible for the reduction of monolayer cell content induced by the compounds without detecting modulations of autophagy or senescence processes. Two of the four compounds (levoglucosenone and its brominated variant) were able to modulate in vitro events associated with tumor progression, such as migratory potential, invasiveness, and proteases secretion. Furthermore, tumor volume and metastatic spread were significantly reduced in vivo after the treatment these two compounds. Here, we could obtain from soybean hulls, a material with almost no commercial value, a variety of chemical compounds useful for breast cancer treatment.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Neoplasias da Mama/patologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Glucose/análogos & derivados , Animais , Antineoplásicos Fitogênicos/química , Apoptose/efeitos dos fármacos , Compostos Bicíclicos Heterocíclicos com Pontes/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Celulose/química , Relação Dose-Resposta a Droga , Glucose/química , Glucose/farmacologia , Humanos , Concentração Inibidora 50 , Camundongos , Camundongos Endogâmicos BALB C , Carga Tumoral/efeitos dos fármacos
5.
J Expo Sci Environ Epidemiol ; 32(1): 146-155, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34083740

RESUMO

BACKGROUND: Trace elements comprise both nutritionally essential and non-essential, and their presence in organisms plays important role in human health. OBJECTIVE: The aim of this study was to evaluate the levels of trace elements, together with cellular and molecular biomarkers, in adolescents from Tierrabomba Island, a Caribbean community located near an industrial area, comparing them with a group living in San Onofre, a reference community. METHODS: Hair and blood samples were obtained from 238 individuals aged 11-18 years old, 131 from Tierrabomba Island and 107 from San Onofre. Trace elements were quantified in hair using ICP-MS. The hematological evaluation was done by peripheral blood smears, and gene expression analysis was carried out through RT-PCR. RESULTS: Thirteen elements were analyzed; eight showed significant differences between sites. In Tierrabomba, arsenic (As) and tungsten (W) registered mean values greater than in San Onofre. In contrast, in the reference site, average values for boron (B), cobalt (Co), zinc (Zn), yttrium (Y), tin (Sn), and barium (Ba) were greater. The peripheral blood film showed differences between populations. Mean lymphocyte percentage was higher in the Island, while eosinophil and monocyte percentages displayed greater means in San Onofre. Some correlations between trace elements and hematological parameters were found, mainly with platelets in Tierrabomba. This trend remained even when partial correlation coefficients were adjusted for age. Levels of gene expression of metallothionein 1X (MT1X) and superoxide dismutase (SOD) registered significant differences between sites, being greater in Tierrabomba. Negative correlations between SOD and As were observed in both sampling sites. Discriminant analysis suggested sampling locations could be differentiated by Zn, Mo, Ba, and MT1X levels. SIGNIFICANCE: Trace elements and the relative gene expression associated with metal exposure are critical exposure biomarkers for coastal communities.


Assuntos
Oligoelementos , Adolescente , Região do Caribe , Criança , Colômbia , Expressão Gênica , Cabelo/química , Humanos , Oligoelementos/análise
6.
J Org Chem ; 85(15): 9969-9978, 2020 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-32644813

RESUMO

The discovery of efficient organocatalysts is generally carried out by thorough experimental screening of different candidates. We recently reported an efficient organocatalyst for iminium-ion-based asymmetric Diels-Alder reactions following a rational design approach. This result encouraged us to test this optimal catalyst in the mechanistically related Friedel-Crafts alkylation of indoles, but to our surprise, almost null enantioselectivity was observed. The results did not significantly improve with structurally related catalysts, and a totally unexpected facial selectivity inversion was also noticed. Using DFT calculations by modeling the competing transition structures with ONIOM, we could unravel the origins of those findings, further employed to predict the most efficient catalyst for this new transformation. The computational results were validated experimentally (up to 92:8 er), providing another successful example of a general strategy to accelerate catalyst development which still remains underexplored.

7.
Bioorg Med Chem Lett ; 30(14): 127247, 2020 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-32527547

RESUMO

A series of levoglucosenone-derived 1,2,3-triazoles and isoxazoles featuring a flexible spacer between the heteroaromatic and anhydropyranose cores have been designed and synthesized following an hetero Michael // 1,3-dipolar cycloaddition path. The use of a design of experiments approach allowed the optimization of the oxa-Michael reaction with propargyl alcohol as nucleophile, a key step for the synthesis of the target compounds. All of the compounds were tested for their anticancer activity on MDA-MB-231 cells, featuring mutant p53. The results highlighted the importance of the introduction of the flexible spacer as well as the higher activity of oxa-Michael isoxazole-derivatives. The most prominent compounds also showed anti-proliferative activities against lung and colon cancer cell lines. The compounds showed enhanced cytotoxic effects in the presence of mutant p53, determined both by endogenous mutant p53 knock down (R280K) and by reintroducing p53 R280K in cells lacking p53 expression.


Assuntos
Antineoplásicos/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Desenho de Fármacos , Glucose/análogos & derivados , Isoxazóis/farmacologia , Triazóis/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Glucose/síntese química , Glucose/química , Glucose/farmacologia , Humanos , Isoxazóis/química , Estrutura Molecular , Relação Estrutura-Atividade , Triazóis/química
8.
Rev. méd. Urug ; 36(1): 99-105, mar. 2020. tab, graf
Artigo em Espanhol | LILACS, BNUY | ID: biblio-1094231

RESUMO

Resumen: La litotricia extracorpórea por ondas de choque para el tratamiento de la urolitiasis es un tratamiento ampliamente aceptado, pero no exento de complicaciones. La pancreatitis aguda que se desencadena inmediatamente posterior a este procedimiento es infrecuente, pero puede ser una complicación grave que amenaza la vida del paciente. La aparición aguda de dolor abdominal y vómitos en las horas posteriores al procedimiento, deben hacer al médico tratante sospechar esta complicación. Presentamos el caso de un paciente joven que luego de someterse a una sesión de litotricia para el tratamiento de una litiasis renal derecha instaló una pancreatitis aguda que requirió ingreso a terapia intensiva y que se suma a los escasos informes de casos publicados en la literatura médica.


Summary: Extracorporeal shock wave lithotripsy to treat urolithiasis is a widely aceptable treatment, although it may involve complications. Acute pancreatitis immediately after the procedures is rather unusual, but it may result in a serious life-threatening complication for patients. The appearance of severe pain and vomits a few hours after the procedure should make physicians suspicious of this complication. The study presents the case of a young patient who developed acute pancreatitis after undergoing lithotripsy to treat lithiasis in the right kidney, requiring his admission to the intensive care unit. This will add up to the scarce reports published in the medical literature.


Resumo: A litotrícia extracorpórea por ondas de choque para o tratamento da urolitíase é um tratamento amplamente aceito, mas não isento de complicações. A pancreatite aguda que se desencadeia imediatamente depois deste procedimento não é frequente, porém pode ser uma complicação grave que ameaça a vida do paciente. O surgimento súbito de dor abdominal e vómitos nas horas seguintes ao procedimento devem induzir à suspeita desta complicação. Apresentamos o caso de um paciente jovem que depois de uma sessão de litotrícia para o tratamento de uma litíase renal direita apresentou uma pancreatite aguda com posterior admissão a terapia intensiva; este caso se agrega aos poucos publicados na literatura médica.


Assuntos
Pancreatite , Litotripsia/efeitos adversos
9.
Environ Sci Pollut Res Int ; 27(12): 14216-14227, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32043249

RESUMO

Mercury (Hg) is one of the heavy metals of concern for fish-eating populations. This pollutant can be released from many sources and generates diverse toxic effects in humans. The aim of this study was to evaluate hematological parameters and their relationship with total Hg (T-Hg) levels in the hair of adolescents from Tierrabomba, an island close to an industrialized area, and also from San Onofre, a reference site. Blood and hair samples were collected from 194 individuals, aged 11-18 years old, as well as sociodemographic and dietary information. The hematological profile showed marked differences between the two sites. Mean values for almost all variables of the red blood cell line, as well as lymphocyte percentage (LYM%) and monocyte percentage (MID%), were greater in Tierrabomba. In contrast, red cell distribution width (RDW), white blood cells (WBC), granulocyte percentage (GRA%), and plateletcrit (PTC) were higher at the reference site. Total Hg mean in Tierrabomba was 1.10 ± 0.07 µg/g, while at San Onofre, it was 1.87 ± 0.11 µg/g. In both places, more than 49% of participants had Hg concentrations over the limit threshold (1 µg/g). Overall mean corpuscular hemoglobin concentration (MCHC) and T-Hg showed a negative correlation (r = - 0.162, p = 0.024). However, positive associations were observed between T-Hg and MID% for Tierrabomba (r = 0.193, p = 0.041), and between T-Hg and mixed cells (MID) for the reference site (r = 0.223, p = 0.044). A significant relationship was found for fish consumption frequency and T-Hg levels (r = 0.360, p < 0.001). These results indicate blood parameters may be affected by Hg even at low-level exposure.


Assuntos
Mercúrio/análise , Adolescente , Animais , Região do Caribe , Criança , Colômbia , Exposição Ambiental/análise , Monitoramento Ambiental , Peixes , Contaminação de Alimentos/análise , Cabelo/química , Humanos
10.
J Org Chem ; 83(7): 3516-3528, 2018 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-29481076

RESUMO

The design and synthesis of biomass-derived triazoles and the in vitro evaluation as potential anticancer agents are described. The discovery of base-catalyzed retro-aza-Michael//aza-Michael isomerizations allowed the exploration of the chemical space by affording novel types of triazoles, difficult to obtain otherwise. Following this strategy, 2,4-disubstituted 1,2,3-triazoles could be efficiently obtained from the corresponding 1,4-disubstituted analogues.

11.
J Bioenerg Biomembr ; 49(6): 453-461, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29043530

RESUMO

Subunit II of cytochrome c oxidase (Cox2) is usually encoded in the mitochondrial genome, synthesized in the organelle, inserted co-translationally into the inner mitochondrial membrane, and assembled into the respiratory complex. In chlorophycean algae however, the cox2 gene was split into the cox2a and cox2b genes, and in some algal species like Chlamydomonas reinhardtii and Polytomella sp. both fragmented genes migrated to the nucleus. The corresponding Cox2A and Cox2B subunits are imported into mitochondria forming a heterodimeric Cox2 subunit. When comparing the sequences of chlorophycean Cox2A and Cox2B proteins with orthodox Cox2 subunits, a C-terminal extension in Cox2A and an N-terminal extension in Cox2B were identified. It was proposed that these extensions favor the Cox2A/Cox2B interaction. In vitro studies carried out in this work suggest that the removal of the Cox2B extension only partially affects binding of Cox2B to Cox2A. We conclude that this extension is dispensable, but when present it weakly reinforces the Cox2A/Cox2B interaction.


Assuntos
Clorófitas/enzimologia , Complexo IV da Cadeia de Transporte de Elétrons/química , Ligação Proteica , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo
12.
J Org Chem ; 82(4): 1873-1879, 2017 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-28209066

RESUMO

The assignment of the relative configuration of spiroepoxides or related quaternary carbon-containing oxiranes can be troublesome and difficult to achieve. The use of GIAO NMR shift calculations can provide helpful assistance in challenging cases of structural elucidation. In this regard, the DP4 probability is one of the most popular methods to be employed when only one set of experimental data is available, though modest results were obtained when dealing with spiroepoxides. Recently, we introduced an improved probability (DP4+) that includes the use of both scaled and unscaled NMR data computed at higher levels of theory. Here, we report a comprehensive study to explore the scope and limitations of the DP4+ methodology in the stereoassignment of terminal or spiroepoxides bearing a wide variety of molecular complexity and conformational freedom. The excellent levels of correct classification achieved were interpreted on the basis of a constructive compensation of errors upon using both scaled and unscaled proton and carbon data. The advantages of the DP4+ methodology in solving two case studies that could not be unequivocally assigned by NOE experiments are also provided.

13.
Org Biomol Chem ; 15(2): 426-434, 2017 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-27924326

RESUMO

The 1,3-dipolar cycloaddition reactions of azomethine ylides is one of the preferred methods for the synthesis of polysubstituted pyrrolidines. The use of chiral dipolarophiles derived from carbohydrates yields enantiomerically pure pyrrolidines, usually in good to excellent endo selectivities, along with other minor stereoisomers. Recently, we found an unusual isomerization event that allowed the isolation of useful pyrrolidines with relative stereochemistries difficult to obtain otherwise. Although a simple and efficient protocol to promote these transformations was developed, the mechanism was not fully unravelled. Herein, after a combination of experimental, spectroscopic and computational studies (using DFT methods) we propose that this isomerization event takes place through a retro-Mannich//Mannich cascade, via the formation of an iminium ion with E geometry.

14.
Beilstein J Org Chem ; 12: 1616-23, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27559414

RESUMO

Chiral acrylic esters derived from biomass were developed as models to have a better insight in the aryl-vinyl π-stacking interactions. Quantum chemical calculations, NMR studies and experimental evidences demonstrated the presence of equilibriums of at least four different conformations: π-stacked and face-to-edge, each of them in an s-cis/s-trans conformation. The results show that the stabilization produced by the π-π interaction makes the π-stacked conformation predominant in solution and this stabilization is slightly affected by the electron density of the aromatic counterpart.

15.
Org Lett ; 18(8): 1748-51, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-27053242

RESUMO

An efficient and straightforward synthesis of a novel 3-thiomannoside derivative (1,2,4,6-tetra-O-acetyl-3-S-acetyl-3-thio-ß-d-mannopyranoside) was developed starting from levoglucosenone. A xanthate-thiocarbonate exchange under acidic conditions was the key step for the new C-S bond. The product was obtained enantiospecifically in very good overall yield.


Assuntos
Manose/síntese química , Espectroscopia de Ressonância Magnética , Manose/química , Estrutura Molecular
16.
Acta investigación psicol. (en línea) ; 6(2): 2450-2458, ago. 2016. tab
Artigo em Espanhol | LILACS | ID: biblio-949436

RESUMO

Resumen La madurez neuropsicológica es el nivel de organización y desarrollo madurativo que permite el desenvolvimiento de funciones conductuales y cognitivas acordes a la edad del individuo. La conducta de gateo es el primer movimiento armónico en el cual el bebé hace uso de su cabeza y de sus extremidades. Dicha conducta permite el establecimiento de conexiones entre los hemisferios cerebrales que dan lugar a la intercomunicación que simplifica el trabajo del cerebro y favorece la maduración de las funciones cognitivas. El objetivo de esta investigación fue comparar la madurez neuropsicológica en niños de 5 y 6 años de edad que presentaron la conducta de gateo con niños que no la presentaron. La muestra estuvo conformada por 50 estudiantes de colegios privados. Fue un estudio cuantitativo con un diseño transversal-descriptivo-comparativo, en el que se usó la historia clínica y el cuestionario para padres de la batería de Evaluación Neuropsicológica Infantil (ENI) de Matute, Rosselli, Ardila y Ostrosky (2007) y del Cuestionario de Madurez Neuropsicológica Infantil (CUMANIN). Se concluyó, a través de los estadísticos aplicados de Shapiro Wilcoxon, al comparar las puntuaciones de los 2 grupos, que la escala de psicomotricidad, posiblemente, depende del gateo. Con respecto al rendimiento, al comparar los 2 grupos con el estadístico Chi-cuadrada, se evidenciaron mejores resultados en 9 escalas del grupo formado por los que presentaron la conducta de gateo.


Neuropsychological maturity is the level of organization and maturational development that allows the development of behavioral and cognitive age-appropriate individual functions, crawling behavior is the first harmonic motion in which the baby uses his head and his both lower extremities as superior, to support and move, it allows the establishment of connections between brain hemispheres, leading to the intercom that simplifies the work of the brain and promotes the maturation of the cognitive functions of the infant, the objective of this research was compare neuropsychological maturity in children 5 and 6 years of age who presented behavior crawling with those who had not, the sample consisted of 50 students from private schools in central Colombia. It was a quantitative study with a comparative-descriptive cross-sectional design, in which the history and the parent questionnaire battery neuropsychological evaluation Infantil (ENI) developed by Matute, Rosselli, Ardila y Ostrosky (2007) and was used Maturity Questionnaire Neuropsychological Children (CUMANIN). First, he made the selected sample, the instruments are applied, and the results were analyzed and finally publicly sustained research. It was concluded through statistical Wilcoxon Shapiro applied to compare the scores of the two groups possibly psychomotor scale depends on crawling; regarding the performance when comparing the 2 groups with the Chi-square statistic best results are evidenced in nine scales the group presented crawling behavior with respect to the group that did not crawl.

17.
J Org Chem ; 80(15): 7626-34, 2015 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-26173931

RESUMO

An efficient organocatalyst for iminium-ion based asymmetric Diels-Alder (DA) reactions has been rationally designed. The most influential structure-activity relationships were determined experimentally, while DFT calculations and NMR studies provided further mechanistic insight. This knowledge guided an in silico screening of 62 different catalysts using an ONIOM(B3LYP/6-31G*:AM1) transition-state modeling, which showed good correlation between theory and experiment. The top-scored compound was easily synthesized from levoglucosenone, a biomass-derived chiral enone, and evaluated in the DA reaction between (E)-cinnamaldehyde and cyclopentadiene. In line with the computational finding, excellent results (up to 97% ee) were obtained. In addition, the catalyst could be easily recovered and reused with no loss in its catalytic activity.

18.
Carbohydr Res ; 402: 67-70, 2015 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-25497334

RESUMO

A short and efficient methodology for the synthesis of chiral dioxa-caged compounds from levoglucosenone, a biomass-derived enone, is herein presented. The key transformation, that involves a cascade 3-step cationic cyclization, was efficiently carried out in high yields and selectivities by Montmorillonite K-10 catalysis. The usefulness of K-10 in related semi-pinacol rearrangements to obtain pyran-3-ones is also shown. Interesting differences in the reactivity pattern was found for epimeric alcohols, and the origins of these findings were determined by DFT calculations.


Assuntos
Bentonita/química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Glucose/análogos & derivados , Configuração de Carboidratos , Catálise , Técnicas de Química Sintética , Glucose/síntese química , Glucose/química , Modelos Moleculares , Estereoisomerismo
19.
Int J Mol Sci ; 15(12): 22042-58, 2014 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-25470023

RESUMO

Zingerone (1) and both chiral forms of zingerol (2) were obtained from dehydrozingerone (3) by biotransformation with filamentous fungi. The bioconversion of 3 with A. fumigatus, G. candidum or R. oryzae allowed the production of 1 as the sole product at 8 h and in 81%-90% at 72 h. In turn, A. flavus, A. niger, C. echinulata, M. circinelloides and P. citrinum produced 1 at 8 h, but at 72 h alcohol 2 was obtained as the major product (74%-99%). Among them, A. niger and M. circinelloides led to the anti-Prelog zingerol (R)-2 in only one step with high conversion rates and ee. Instead, C. echinulata and P. citrinum allowed to obtain (S)-2 in only one step, with high conversion rates and ee. Both chiral forms of 2 were tested for antifungal properties against a panel of clinically important fungi, showing that (R)-, but not (S)-2 possessed antifungal activity.


Assuntos
Antifúngicos/farmacologia , Biocatálise/efeitos dos fármacos , Aromatizantes/metabolismo , Fungos/metabolismo , Guaiacol/análogos & derivados , Biotransformação/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Ésteres/química , Aromatizantes/química , Aromatizantes/farmacologia , Fungos/efeitos dos fármacos , Guaiacol/química , Guaiacol/metabolismo , Guaiacol/farmacologia , Testes de Sensibilidade Microbiana , Espectroscopia de Prótons por Ressonância Magnética , Estereoisomerismo , Fatores de Tempo
20.
Rev. costarric. salud pública ; 22(1): 68-75, ene.-jun. 2013. tab
Artigo em Inglês | LILACS | ID: lil-684396

RESUMO

Objective: To describe the use of chemical insecticides throughout history as the main tool to fight against Aedes aegypti, a vector of dengue virus. Methods: A text mining approach was conducted on databases, such as PUBMED and SCIENCE DIRECT, using the keywords “Aedes aegypti”, combined with the words “insecticides”, “resistance”, “organochlorines”, “organophosphates”, “carbamates” and “pyrethroids”. Results related to historical information dealing with the chemical control of Aedes aegypti, in particular those containing data on insecticide resistance for this species, were scrutinized and analyzed. Results: Different chemical groups have been utilized to control A. aegypti, including organochlorine, organophosphate, carbamate and pyrethroid insecticides. In general, the tendency has been to replace a particular pesticide, for which resistance had been detected, for a new one, mosquito-sensitive, and with little evidence of deleterious effects derived from its use. The spread of resistance has been registered in several countries of America, Asia and Africa. Two mechanisms have been highly cited to be responsible for the resistance; the increase activity of detoxifying enzymes, and structural changes in the insecticide target site, mostly within the central nervous system. Conclusion: Excessive use of chemical insecticides and the lack of dosing control have led to widespread resistance in A. aegypti, as no “safer” alternative chemical options are available for vector control in different countries, impacting human health.


Objetivo: Describir el uso de insecticidas químicos a través de la historia como la principal herramienta contra Aedes aegypti, un mosquito vector del virus del dengue. Métodos: Una búsqueda en minería de textos fue realizada en bases de datos como PubMedy Science Direct, utilizando las palabras clave “Aedes aegypti”, en combinación con “insecticidas”, “resistencia”, “organoclorados”, “organofosforados”,“carbamatos” y “piretroides”.Resultados afines con la información histórica relacionada con el control químico del mosquito Aedes aegypti, en particular las que contienen datos sobre la resistencia a insecticidas de esta especie, fueron examinados y analizados. Resultados: Diferentes grupos químicos han sido desarrollados para el control de A. aegypti, siendo los más utilizados organoclorados, organofosforados, carbamatos y piretroides. En general, la tendencia ha sido la de sustituir un pesticida particular, para el que ha sido detectado resistencia, por uno nuevo, mosquito-sensible, y con evidencia de efectos perjudiciales derivados de su uso. La propagación de la resistencia se ha registrado en varios países de América, Asia y África. Dos mecanismos han sido altamente referenciados de ser responsable de la resistencia, el aumento de actividad de las enzimas de desintoxicación, y los cambios estructurales en el sitio de destino de los insecticidas, en su mayoría dentro del sistema nervioso central. Conclusión: El uso excesivo de insecticidas químicos y la falta de control de dosificación han dado lugar a una resistencia generalizada en Aedes aegypti, y alternativas químicas “más seguras” no están disponibles para el control de vectores en diferentes países, afectando la salud humana.


Assuntos
Colômbia , Substâncias Tóxicas , Aedes , Controle de Vetores de Doenças , Dengue , Inseticidas Organofosforados , Inseticidas
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