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BACKGROUND: Chitosan is a cheap, accessible, nontoxic, biocompatible, and biodegradable compound. Also, this polysaccharide possesses antibacterial and anti-inflammatory properties. Consequently, a wide range of chitosan applications in the dentistry field has been explored. This work aimed to conduct a systematic review to address the clinical efficacy of chitosan for the treatment of oral mucositis. MATERIAL AND METHODS: The design of the included studies were observational studies, randomized clinical trials (RCT), and non-randomized clinical trials (non-RCT), whereas, a series of cases, in vivo, and in vitro studies were excluded. The search was performed in PubMed, Web of Science, Scopus, Dentistry and Oral Sciences Source, and ClinicalTrials. Gray literature was searched at Google Scholar. Relevant data from all included studies were recorded. The risk of bias (using RoB 2) and the quality (using Grading of Recommendations Assessment, Development, and Evaluation, GRADE) assessments were carried out. RESULTS: From the 8413 records screened, 5 clinical trials fully met the eligibility criteria, which comprised a total of 192 participants suffering oral lesions and pain related to oral mucositis. 100% of the included studies exhibited a high risk of bias. The quality of the studies was between low and very low. CONCLUSIONS: The results of the included studies suggest that chitosan can diminish pain and improve the healing of ulcers in oral mucositis. However, there is no conclusive evidence of chitosan as a superior treatment for oral mucositis compared with other current therapies.
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Quitosana , Estomatite , Humanos , Mucosa Bucal , Quitosana/uso terapêutico , Estomatite/tratamento farmacológico , Inflamação , DorRESUMO
The aim of this article is to show a way to extend the usefulness of the Generalized Bernoulli Method (GBM) with the purpose to apply it for the case of variational problems with functionals that depend explicitly of all the variables. Moreover, after expressing the Euler equations in terms of this extension of GBM, we will see that the resulting equations acquire a symmetric form, which is not shared by the known Euler equations. We will see that this symmetry is useful because it allows us to recall these equations with ease. The presentation of three examples shows that by applying GBM, the Euler equations are obtained just as well as it does the known Euler formalism but with much less effort, which makes GBM ideal for practical applications. In fact, given a variational problem, GBM establishes the corresponding Euler equations by means of a systematic procedure, which is easy to recall, based in both elementary calculus and algebra without having to memorize the known formulas. Finally, in order to extend the practical applications of the proposed method, this work will employ GBM with the purpose to apply it for the case of solving isoperimetric problems.
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OBJECTIVE: Hunter syndrome, or mucopolysaccharidosis type II (MPS II), is caused by deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS), which is responsible for degrading heparan and dermatan sulfate. The IDS gene is located on chromosome Xq28; pathological variants in this gene mostly consist of missense mutations and small and larger deletions, which produce different phenotypes. However, there is only one record in our population concerning the molecular mechanism of this disease; a genotype-phenotype description is not available. PATIENTS AND METHODS: There were included 24 unrelated male patients; clinical features were recorded at a database, fluorometric IDS enzyme activity testing was done for each individual, followed by Sanger sequencing to identify mutations. RESULTS: The mutational spectrum was found in 16 out of 24 Mexican patients with MPS II, and its range of phenotypes was described. The most frequent variants were of the missense type. The most affected exons were exon 3 (c.275T>G, c.284_287del, c.325T>C), exon 8 (c.1035G>C, c.550G>A), exon 9 (c.1403G>C, c.1229_1229del), and exon 7 (c.979A>C; this variant has not been previously reported). Exon 5 (c.438C>T, a non-pathogenic variant) was the least frequent. It was also found that the most severely affected patients were those with large deletions (2 out of 24) [rsaIDS: IDSP1 (P164)x0, FMR1, AFF2 (P164)x2] involving genes and pseudogenes. We found 2 patients with a synonymous mutation in exon 4. CONCLUSIONS: Our results confirmed reports in the literature, since the most frequent variants were reported in exons 3 and 8. However, this result varies from one previous report in our population, which mentions large deletions and rearrangements as the most frequent alterations, since complex rearrangements were not found. According to what has been previously found, the most severely affected patients are those in which a whole gene has been deleted.
Assuntos
Iduronato Sulfatase , Mucopolissacaridose II , Proteína do X Frágil da Deficiência Intelectual/genética , Humanos , Iduronato Sulfatase/genética , Ácido Idurônico , Masculino , Mucopolissacaridose II/epidemiologia , Mucopolissacaridose II/genética , Mutação , FenótipoRESUMO
INTRODUCTION: Early diagnosis based on clinical findings, neurophysiological studies and serum antibody titres allows early initiation of symptomatic treatment and oncological screening. Reports of patients with LEMS in Latin America are scarce. AIM: This article aims to describe the characteristics of patients with LEMS from a private centre in Buenos Aires, Argentina, and to compare them with those of other series that have been published. PATIENTS AND METHODS: The medical records of 13 patients with LEMS with clinical findings, compatible electromyogram and/or positive antibodies were reviewed. Follow-up was performed until associated neoplasia was ruled out or confirmed according to the recommended algorithms. RESULTS: Four patients were diagnosed with T-LEMS, two of them with small-cell lung carcinoma. Of the nine patients with NT-LEMS, five had a DELTA-P score of 3 and 4. Nine patients presented with the classic clinical triad from the onset of the disease. All patients had electromyogram findings compatible with presynaptic neuromuscular plaque defect. Of the total, 70% improved symptomatically with pyridostigmine. CONCLUSIONS: The clinical findings, together with compatible neurophysiological studies, are sufficient for the diagnosis of LEMS. The relationship between the DELTA-P score and the risk of small-cell lung carcinoma could not be replicated. Symptomatic treatment with pyridostigmine represents an effective therapeutic alternative.
TITLE: Síndrome miasteniforme de Lambert-Eaton.Introducción. El síndrome miasteniforme de Lambert-Eaton (LEMS) es una patología paraneoplásica (T-LEMS) o idiopática autoinmunitaria (NT-LEMS) ocasionada por autoanticuerpos contra los canales de calcio dependientes del voltaje presinápticos de la unión neuromuscular. El 60% de los T-LEMS se asocia a carcinoma de pulmón de células pequeñas. Una puntuación Dutch-English LEMS Tumor Association Prediction (DELTA-P) mayor de 3 denota un riesgo elevado de dicha asociación. El diagnóstico precoz fundado en los hallazgos clínicos, estudios neurofisiológicos y dosificación de títulos de anticuerpos en el suero permite iniciar tempranamente el tratamiento sintomático y la búsqueda oncológica. Son escasos los informes de pacientes con LEMS en Latinoamérica. Objetivo. Describir las características de pacientes con LEMS de un centro privado de Buenos Aires, Argentina, y compararlas con las de otras series publicadas. Pacientes y métodos. Se revisaron historias clínicas de 13 pacientes con LEMS con hallazgos clínicos, electromiograma compatible y/o anticuerpos positivos. Se realizó seguimiento hasta descartar o confirmar una neoplasia asociada de acuerdo con los algoritmos recomendados. Resultados. Cuatro pacientes presentaron diagnóstico de T-LEMS, dos de ellos con carcinoma de pulmón de células pequeñas. De los nueve pacientes con NT-LEMS, cinco presentaron una puntuación DELTA-P de 3 y 4. Nueve pacientes presentaron la tríada clínica clásica desde el inicio. Todos los pacientes presentaron en el electromiograma hallazgos compatibles con defecto de placa neuromuscular presináptico. El 70% mejoró sintomáticamente con piridostigmina. Conclusiones. Los hallazgos clínicos, junto con los estudios neurofisiológicos compatibles, resultan suficientes para el diagnóstico de LEMS. No pudo replicarse la relación entre puntuación DELTA-P y riesgo de carcinoma de pulmón de células pequeñas. El tratamiento sintomático con piridostigmina representa una alternativa terapéutica eficaz.
Assuntos
Síndrome Miastênica de Lambert-Eaton/epidemiologia , Adolescente , Adulto , Idoso , Argentina/epidemiologia , Carcinoma de Células Pequenas/complicações , Eletromiografia , Feminino , Humanos , Imunoglobulinas Intravenosas/uso terapêutico , Síndrome Miastênica de Lambert-Eaton/tratamento farmacológico , Síndrome Miastênica de Lambert-Eaton/etiologia , Neoplasias Pulmonares/complicações , Masculino , Pessoa de Meia-Idade , Junção Neuromuscular/fisiopatologia , Brometo de Piridostigmina/uso terapêutico , Estudos Retrospectivos , Avaliação de Sintomas , Adulto JovemRESUMO
BACKGOUND: Studying enzymes that determine glucose-1P fate in carbohydrate metabolism is important to better understand microorganisms as biotechnological tools. One example ripe for discovery is the UDP-glucose pyrophosphorylase enzyme from Rhodococcus spp. In the R. jostii genome, this gene is duplicated, whereas R. fascians contains only one copy. METHODS: We report the molecular cloning of galU genes from R. jostii and R. fascians to produce recombinant proteins RjoGalU1, RjoGalU2, and RfaGalU. Substrate saturation curves were conducted, kinetic parameters were obtained and the catalytic efficiency (kcat/Km) was used to analyze enzyme promiscuity. We also investigated the response of R. jostii GlmU pyrophosphorylase activity with different sugar-1Ps, which may compete for substrates with RjoGalU2. RESULTS: All enzymes were active as pyrophosphorylases and exhibited substrate promiscuity toward sugar-1Ps. Remarkably, RjoGalU2 exhibited one order of magnitude higher activity with glucosamine-1P than glucose-1P, the canonical substrate. Glucosamine-1P activity was also significant in RfaGalU. The efficient use of the phospho-amino-sugar suggests the feasibility of the reaction to occur in vivo. Also, RjoGalU2 and RfaGalU represent enzymatic tools for the production of (amino)glucosyl precursors for the putative synthesis of novel molecules. CONCLUSIONS: Results support the hypothesis that partitioning of glucosamine-1P includes an uncharacterized metabolic node in Rhodococcus spp., which could be important for producing diverse alternatives for carbohydrate metabolism in biotechnological applications. GENERAL SIGNIFICANCE: Results presented here provide a model to study evolutionary enzyme promiscuity, which could be used as a tool to expand an organism's metabolic repertoire by incorporating non-canonical substrates into novel metabolic pathways.
Assuntos
Proteínas de Bactérias/genética , Glucosamina/metabolismo , Rhodococcus/genética , UTP-Glucose-1-Fosfato Uridililtransferase/genética , Proteínas de Bactérias/metabolismo , Duplicação Gênica , Genes Bacterianos , Redes e Vias Metabólicas , Rhodococcus/enzimologia , Rhodococcus/metabolismo , UTP-Glucose-1-Fosfato Uridililtransferase/metabolismoRESUMO
INTRODUCTION: Establishing differential diagnosis between different inflammatory causes of acute transverse myelitis (ATM) can be difficult. The objective of this study was to see which clinical, imaging or laboratory findings best contribute to confirm ATM etiology. METHODS: We reviewed clinical history, MRI images, CSF and serum laboratory tests in a retrospective study of patients presenting ATM. Univariate and multivariate multinomial logistic regression analysis was performed for each of the items listed above. RESULTS: One hundred and seventy-two patients were analyzed in the study: 68 with multiple sclerosis (MS), 67 presenting idiopathic myelitis (IM; 23 of which were recurrent), 21 who developed positive systemic-antibodies associated myelitis (SAb-M) and 16 with neuromyelitis optica spectrum disorders (NMOSD). The following factors were associated with increased risk of developing MS: lower values in the modified Rankin scale at admission; positive oligoclonal bands (OCB); higher spinal cord lesion load; presence of brain demyelinating lesions; and disease recurrence. Longitudinally extended (LE) lesions, brain demyelinating lesions, and recurrences also contributed to final diagnosis of NMOSD. Multivariate multinomial logistic regression analysis showed presence of LE lesions increased risk of NMOSD and recurrence of ATM. Whereas, brain demyelinating lesions, and presence of OCB increased risk of MS. CONCLUSIONS: ATM etiology may be clarified on the basis of spinal cord and brain MRI findings, together with CSF biochemistry and serum laboratory test results, allowing more timely and exact diagnosis as well as specific therapy for cases of uncertain origin.
Assuntos
Mielite Transversa , Neuromielite Óptica , Diagnóstico Diferencial , Humanos , Imageamento por Ressonância Magnética , Mielite Transversa/diagnóstico por imagem , Recidiva Local de Neoplasia , Neuromielite Óptica/diagnóstico por imagem , Estudos RetrospectivosRESUMO
OBJECTIVE: The rs2234694 and 50 bp insertion/deletion (Ins/Del) polymorphisms of the SOD1 gene have been shown to be associated with many diseases, but in breast cancer (BC) their association has not been detected. The purpose of this study was to determine the frequency and association of SOD1 gene polymorphisms (rs2234694 and 50 bp Ins/Del) in BC patients in the Mexican population. MATERIALS AND METHODS: The SOD1 polymorphisms were determined by Polymerase Chain Reaction (PCR) in Mexican healthy subjects and BC patients. RESULTS: The rs2234694 polymorphism was associated with BC susceptibility when BC patients and the control group were compared for the AC genotype (p<0.0001), the AC/CC genotype (dominant model: p<0.0001), and the C allele (p<0.0001). The 50 bp Ins/Del polymorphism was associated with BC susceptibility for the Del allele (p=0.048), although the association between the dominant model AC/CC (rs2234694) and BC patients was evident for menopause [adjusted odds ratio (OR) 1.65 (95% CI 1.05-2.7); p=0.048], Ki-67 (≥15%) (OR1.9, 95% CI 1.14- 3.16, p=0.016), and the presence of DM2 (OR 2.4, 95% CI 1.35- 4.31, p=0.003). A protective association for BC of the rs2234694 polymorphism was observed in patients younger than 50 years positive for estrogen receptor (ER) and progesterone receptor (PR), carrying the AC genotypes (OR 0.47, 95% CI 0.23-0.94, p= 0.033) and CC (OR 0.11, 95% CI 0.013-1.07, p=0.047). The association between the InsDel/DelDel (dominant model; 50 bp Ins/Del) genotype and BC with metastatic lymph nodes (OR 1.5, 95% CI 1.1-2.25, p=0.019), hematologic toxicity (OR 1.5, 95%CI 1.1-2.23, p=0.015), gastric toxicity (OR 1.5, 95%CI 1.1-2.07, p=0.030), and Ki-67 (≥15%) (OR1.6, 95%CI 1.2-2.26, p=0.002) was evident, indicating that these factors may contribute significantly to BC risk. The C/Ins haplotype was also associated with BC susceptibility (OR3.47, 95% CI 1.62-7.74, p=0.001). CONCLUSIONS: rs2234694 and 50 bp Ins/Del polymorphisms in the SOD1 gene were associated with BC susceptibility in a Mexican population. A protective association for BC of the rs2234694 polymorphism was observed in patients younger than 50 years positive for ER and PR, carrying the AC genotypes. The haplogenotypes AA/InsIns and AC/InsDel could contribute significantly to BC risk in gastric and hematologic toxicities, metastatic lymph nodes, and the presence of DM2 in the Mexican population analyzed.
Assuntos
Neoplasias da Mama/genética , Polimorfismo Genético/genética , Superóxido Dismutase-1/genética , Alelos , Neoplasias da Mama/patologia , Feminino , Humanos , México , Pessoa de Meia-Idade , Fatores de Risco , Superóxido Dismutase-1/sangueRESUMO
BACKGROUND: An essential element imbalance in the joint might favor gradual degeneration of the articular cartilage. It has been reported that cadmium (Cd) plays an antagonistic role with regards to the presence of essential elements, such as zinc (Zn), iron (Fe), and manganese (Mn), which may favor the development of disabling diseases, like osteoarthritis (OA) and osteoporosis. METHODS: 3D cultures of human chondrocytes were phenotyped with the Western blot technique and structurally evaluated with histological staining. The samples were exposed to 1, 5, and 10 µM of CdCl2 for 12 h, with a non-exposed culture as control. The concentration of Cd, Fe, Mn, Zn, chromium (Cr), and nickel (Ni) was quantified through plasma mass spectrometry (ICP-MS). The data were analyzed with a Kruskal Wallis test, a Kendall's Tau test and Spearman's correlation coefficient with the Stata program, version 14. RESULTS: Our results suggest that Cd exposure affects the structure of micromass cultures and plays an antagonistic role on the concentration of essential metals, such as Zn, Ni, Fe, Mn, and Cr. CONCLUSION: Cd exposure may be a risk factor for developing joint diseases like OA, as it can interfere with cartilage absorption of other essential elements that maintain cartilage homeostasis.
Assuntos
Cádmio/farmacologia , Condrócitos/efeitos dos fármacos , Condrócitos/metabolismo , Adulto , Western Blotting , Cádmio/metabolismo , Humanos , Imunofenotipagem , Ferro/metabolismo , Masculino , Espectrometria de Massas , Níquel/metabolismo , Osteoartrite/metabolismo , Adulto Jovem , Zinco/metabolismoRESUMO
This study assessed the spatial and temporal nutrient variability in the El Fuerte River basin in northwestern Mexico, considering its effects on the water trophic status as well as the nutrient loading to the Gulf of California. Physicochemical parameters, inorganic species of nitrogen, phosphate, total nitrogen, total phosphorus, and chlorophyll-a (chl-a) were quantified at 16 selected sites along the river in April (dry season) and October (rainy season) 2017. Mean concentrations of nutrients during dry and rainy seasons were 36.3 ± 24.1 and 55.1 ± 74.6 µg L-1 of total ammonia nitrogen, 3.4 ± 3.6 and 4.5 ± 3.5 µg L-1 of NO2--N, 190.8 ± 256.0 and 163.6 ± 261.0 µg L-1 of NO3--N, 42.4 ± 44.2 and 104.9 ± 76.2 µg L-1 of PO43--P, 1.0 ± 1.3 and 691 ± 2242 mg L-1 of TN, 0.06 ± 0.06 and 0.08 ± 0.09 mg L-1 of TP, and 0.9 ± 0.6 and 2.0 ± 0.9 µg L-1 of chl-a with significant differences (p < 0.05) between sites and seasons. When waters are transported downstream, nutrient levels are enriched by 4 to 35 times compared to those upstream due to increased population and agriculture downstream, confirming the hypothesis of the study. The calculated TN and TP fluxes were 1.23 × 104 and 3.57 × 101 ton year-1, respectively. Factor analysis indicated that inorganic nitrogen species and phosphorus are the main factors affecting the river water quality. Despite N excess during the rainy season, the river reached mesotrophic waters due to phosphorus limitation. This suggests the need to establish a water quality monitoring program to understand the vulnerability of the river course to changes in its trophic state.
Assuntos
Monitoramento Ambiental , Nitrogênio , Fósforo , Rios , Poluentes Químicos da Água , Clorofila/análise , México , Nitrogênio/análise , Nutrientes/análise , Fósforo/análise , Rios/química , Estações do Ano , Poluentes Químicos da Água/análiseRESUMO
The aim of this article is to show the way to get both, exact and analytical approximate solutions for certain variational problems with moving boundaries but without resorting to Euler formalism at all, for which we propose two methods: the Moving Boundary Conditions Without Employing Transversality Conditions (MWTC) and the Moving Boundary Condition Employing Transversality Conditions (METC). It is worthwhile to mention that the first of them avoids the concept of transversality condition, which is basic for this kind of problems, from the point of view of the known Euler formalism. While it is true that the second method will utilize the above mentioned conditions, it will do through a systematic elementary procedure, easy to apply and recall; in addition, it will be seen that the Generalized Bernoulli Method (GBM) will turn out to be a fundamental tool in order to achieve these objectives.
RESUMO
An imbalance in the redox state, increased levels of lipid precursors and overactivation of de novo lipogenesis determine the development of fibrosis during nonalcoholic steatohepatitis (NASH). We evaluated the modulation of NADPH-producing enzymes associated with the antifibrotic, antioxidant and antilipemic effects of nicotinamide (NAM) in a model of NASH induced by excess fructose consumption. Male rats were provided drinking water containing 40% fructose for 16 weeks. During the last 12 weeks of fructose administration, water containing NAM was provided to some of the rats for 5 h/day. The biochemical profiles and the ghrelin, leptin, lipoperoxidation and TNF-α levels in serum and the glucose-6-phosphate dehydrogenase (G6PD), malic enzyme (ME) and NADP+-dependent isocitric dehydrogenase (IDP) levels, the reduced/oxidized glutathione (GSH/GSSG) and reduced/oxidized nicotinamide adenine dinucleotide (phosphate) (NAD(P)H/NAD(P)+) ratios, and the levels of various lipogenic and fibrotic markers in the liver were evaluated. The results showed that hepatic fibrosis induced by fructose consumption was associated with weight gain, hunger-satiety system dysregulation, hyperinsulinemia, dyslipidemia, lipoperoxidation and inflammation. Moreover, increased levels of hepatic G6PD and ME activity and expression, the NAD(P)H/NAD(P)+ ratios, and GSSG concentration and increased expression of lipogenic and fibrotic markers were detected, and these alterations were attenuated by NAM administration. Specifically, NAM diminished the activity and expression of G6PD and ME, and this effect was associated with a decrease in the NADPH/NADP+ ratios, increased GSH levels and decreased lipoperoxidation and inflammation, ameliorating fibrosis and NASH development. NAM reduces liver steatosis and fibrosis by regulating redox homeostasis through a G6PD- and ME-dependent mechanism.
Assuntos
Fígado Gorduroso/metabolismo , Fígado Gorduroso/prevenção & controle , Niacinamida/farmacologia , Animais , Antioxidantes/metabolismo , Frutose/efeitos adversos , Frutose/metabolismo , Glucose/metabolismo , Glutationa/metabolismo , Homeostase , Metabolismo dos Lipídeos/fisiologia , Lipídeos/biossíntese , Lipogênese/fisiologia , Fígado/metabolismo , Fígado/patologia , Cirrose Hepática/patologia , Masculino , NAD/metabolismo , NADP/metabolismo , Niacinamida/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , Oxirredução/efeitos dos fármacos , Ratos , Ratos Sprague-DawleyRESUMO
INTRODUCCIÓN: El divertículo de Meckel es un remanente del conducto onfalomesentérico y su prevalencia es del 2%. CASO CLÍNICO: Niño de 12 años con dolor abdominal, acompañado de evacuaciones mucosanguinolentas y hematemesis, con masa en cuadrante inferior derecho. En la laparotomía quirúrgica se encontró invaginación, y se realizó desinvaginación y resección del divertículo de Meckel. CONCLUSIÓN: La asociación de divertículo de Meckel con tejido pancreático heterotópico en niños es poco frecuente. Clínicamente, su principal manifestación es la invaginación intestinal en la literatura revisada, y el ultrasonido constituye el mejor estudio para el diagnóstico de invaginación intestinal, no así para el divertículo de Meckel o el tejido pancreático heterotópico, en los que la tomografía sería una opción. INTRODUCTION: Meckel's diverticulum is a remnant of the omphalomesenteric duct and its prevalence is 2%. CLINICAL CASE: A 12-year-old male with abdominal pain, accompanied by muco-sanguineous evacuations and hematemesis, with right lower quadrant mass. In the laparotomy, invasion was found; intussusception reduction and resection of the Meckel's diverticulum was performed. CONCLUSION: The association of Meckel's diverticulum with heterotopic pancreatic tissue in children is rare, its main manifestation is intussusception and ultrasound is an option for diagnosis.
Assuntos
Coristoma/complicações , Doenças do Colo/etiologia , Doenças do Íleo/etiologia , Intussuscepção/etiologia , Divertículo Ileal/complicações , Pâncreas , Anastomose Cirúrgica , Criança , Coristoma/patologia , Coristoma/cirurgia , Doenças do Colo/cirurgia , Humanos , Doenças do Íleo/cirurgia , Intussuscepção/cirurgia , Masculino , Divertículo Ileal/patologiaRESUMO
The equatorial orientation of reproductive structures is known in some columnar cacti from extratropical deserts. It has been hypothesised that photosynthetically active radiation (PAR) interception is the main reason for this orientation, because of its key effect on nocturnal CO2 uptake. However, there are no studies addressing both the effect of PAR and its consequence, carbon gain, on fruit orientation. Accordingly, we tested whether PAR and carbon gain could explain the southern fruit orientation of Myrtillocactus geometrizans, an inter-tropical columnar cactus. We studied three populations of M. geometrizans in Mexico. For each population, azimuth of fruits, total daily PAR, nocturnal acid accumulation (NAA) and fruit production were measured. The relationships between rib orientation and number of fruits, as well as total daily PAR, were evaluated using periodic regressions. The effect of total daily PAR and NAA on number of fruits was assessed using generalised linear models. During spring, mean fruit orientation had a south azimuth for three populations. Likewise, rib orientation had a significant effect on fruit production, with the south-facing ribs having the maximum number of fruits. Total daily PAR was highest in the south-facing ribs, at least for those in the northern and central populations. Furthermore, during spring, there was a significant positive effect of total daily PAR and NAA on fruit production. Our results provide strong evidence that the higher carbon gain in equatorial ribs, through a highest interception of PAR, would be the responsible factor for equatorial orientation of fruits in an inter-tropical columnar cactus.
Assuntos
Cactaceae/fisiologia , Carbono/metabolismo , Frutas/fisiologia , Fotossíntese/efeitos da radiação , Cactaceae/efeitos da radiação , Dióxido de Carbono/metabolismo , Frutas/efeitos da radiação , México , Estações do Ano , Luz SolarRESUMO
The endemic Mexican cactus, Mammillaria pectinifera, shows low dispersal capabilities and isolated populations within the highly dissected landscape of Tehuacán Valley. These characteristics can restrict gene flow and act upon the genetic divergence and speciation in arid plants. We conducted a phylogeographic study to determine if the origin, current distribution, and genetic structure of M. pectinifera were driven by Quaternary geomorphic processes. Sequences of the plastids psbA-trnH and trnT-trnL obtained from 66 individuals from seven populations were used to estimate genetic diversity. Population differentiation was assessed by an analysis of molecular variance. We applied a stepwise phylogenetic calibration test to determine whether species origin and genetic divergence among haplotypes were temporally concordant with recognizable episodes of geomorphic evolution. The combination of plastid markers yielded six haplotypes, with high levels of haplotype diversity (h = 0.622) and low nucleotide diversity (π = 0.00085). The populations were found to be genetically structured (F(ST) = 0.682; P < 0.00001), indicating that geographic isolation and limited dispersal were the primary causes of genetic population differentiation. The estimated origin and divergence time among haplotypes were 0.017-2.39 and 0.019-1.237 mya, respectively, which correlates with Pleistocene tectonics and erosion events, supporting a hypothesis of geomorphically-driven geographical isolation. Based on a Bayesian skyline plot, these populations showed long term demographic stability, indicating that persistence in confined habitats has been the main response of this species to landscape changes. We conclude that the origin and haplotype divergence of M. pectinifera were a response to local Quaternary geomorphic evolution.
Assuntos
Cactaceae/genética , Evolução Molecular , Ecossistema , Haplótipos , México , Filogeografia , Polimorfismo GenéticoRESUMO
Oxygen interruption leads to death when re-oxygenation is not promptly re-established. Re-oxygenation triggers a cascade of biochemical events for restoring function at the cost of improper homeostasis. The effects observed long after perinatal asphyxia (PA) have been explained by over-expression of sentinel proteins, such as poly(ADP-ribose) polymerase-1 (PARP-1), competing for NAD(+) during re-oxygenation, leading to the idea that sentinel protein inhibition constitutes a therapeutic strategy. We studied the effects of nicotinamide and theophylline on PARP-1 activity assayed in brain and peripheral (heart) rat tissue 1-24 h after birth, as well as on changes in behaviour and monoamine neurotransmission in adult rats. PA was induced by immersing rat foetuses into a water bath for 0 or 21 min. After resuscitation, the pups were treated with nicotinamide (0.8 mmol/kg, i.p.), theophylline (0.14 mmol/kg, i.p.) or saline (0.9% NaCl) and nurtured by surrogate dams, pending behavioural and microdialysis experiments, or euthanised after birth for assaying PARP-1 activity. To estimate the in vivo distribution of a single dose of nicotinamide or theophylline into brain and peripheral compartment, a series of animals were implanted with microdialysis probes, one into the brain and other subcutaneously, 1 h after birth, assaying the drugs with a HPLC-UV system. Nicotinamide, but not theophylline prevented the long-term effects induced by PA. Only nicotinamide produced a consistent decrease in PARP-1 activity in brain and heart, whether assayed in control or asphyxia-exposed pups. The present results support the idea that the long-term effects induced by PA imply PARP-1 over-activation.
Assuntos
Asfixia/metabolismo , Comportamento Animal/efeitos dos fármacos , Niacinamida/farmacologia , Inibidores de Fosfodiesterase/farmacologia , Poli(ADP-Ribose) Polimerases/metabolismo , Teofilina/farmacologia , Complexo Vitamínico B/farmacologia , Animais , Animais Recém-Nascidos/metabolismo , Asfixia Neonatal/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Coração/efeitos dos fármacos , Humanos , Recém-Nascido , Microdiálise , Modelos Animais , Miocárdio/metabolismo , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/efeitos dos fármacos , Ratos , Ratos WistarRESUMO
Adsorption isotherms of BTX aromatic hydrocarbons (benzene, toluene, and p-xylene) on pristine (SiO2) and metal-doped (Ag-SiO2, Cu-SiO2 and Fe-SiO2) mesoporous and microporous substrates were measured and interpreted. These adsorbents were synthesized by the sol-gel procedure and their BTX sorption isotherms were obtained by the gas chromatographic technique (GC) at several temperatures in the range 423-593 K. The uptake amount of these hydrocarbon adsorptives on SiO2, Ag-SiO2, Cu-SiO2 and Fe-SiO2 mesoporous and microporous substrates was temperature-dependent. Additionally, the interaction of BTX molecules with the pore walls was evaluated by means of the corresponding isosteric heat of adsorption (qst), which was found to follow the next increasing sequence: qst (benzene)Assuntos
Derivados de Benzeno/química
, Benzeno/química
, Recuperação e Remediação Ambiental/métodos
, Dióxido de Silício/química
, Adsorção
, Cobre/química
, Ferro/química
, Porosidade
, Prata/química
, Tolueno/química
, Xilenos/química
RESUMO
A novel topical ophthalmic formulation of the preferential COX-2 inhibitor meloxicam has recently been developed. The purpose of the present study was to evaluate the efficacy and safety of this novel 0.03% meloxicam solution with regard to a reference 0.1% diclofenac formulation in a prospective, parallel, randomized, multicenter, double-blind study. Two groups of patients submitted to phacoemulsification with intraocular lens implantation were formed. Patients in one group were treated with meloxicam and those in the other group with diclofenac. Dosing was 1 drop t.i.d. for 30 days, beginning the first day after surgery, for both treatments. Inflammation was assessed by the presence of cells in the anterior chamber, anterior chamber flare, ciliary flush, photophobia and pain. Both treatments significantly reduced these indicators. Topical meloxicam and diclofenac produced a similar degree of burning sensation and conjunctival hyperemia. There was no significant difference between treatments in any of the measured parameters. It is concluded that the novel meloxicam solution is effective and safe. Meloxicam, however, did not offer any significant benefit over the diclofenac formulation in patients submitted to cataract surgery.