Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 93
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
Ecology ; 98(2): 412-424, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27861787

RESUMO

Predation is considered to be an important factor structuring natural communities. However, it is often difficult to determine how it may influence long-term, broad-scale, diversity patterns, particularly in diverse tropical systems. Biological introductions can provide powerful insight to test the sustained consequences of predation in natural communities, if pre-introduction data are available. Half a century ago, Zaret and Paine demonstrated strong and immediate community-level effects following the introduction of a novel apex predator (peacock bass, Cichla monoculus) into Lake Gatun, Panama. To test for long-term changes associated with this predator introduction, we followed up on their classic study by replicating historical sampling methods and examining changes in the littoral fish community at two sites in Lake Gatun 45 years post-introduction. To broaden our inference, we complemented this temporal comparison with a spatial analysis, wherein we compared the fish communities from two lakes with and one lake without peacock bass. Comparisons with historical data revealed that the peacock bass remains the most abundant predator in Lake Gatun. Furthermore, the collapse of the littoral prey community observed immediately following the invasion has been sustained over the past 45 years. The mean abundance of native littoral fish is now 96% lower than it was prior to the introduction. Diversity (rarefied species richness) declined by 64% post-introduction, and some native species appear to have been locally extirpated. We observed a similar pattern across invaded and uninvaded lakes: the mean abundance of native fishes was 5-40 times lower in lakes with (Gatun, Alajuela) relative to the lake without peacock bass (Bayano). In particular, small-bodied native fishes (Characidae, Peociliidae), which are common prey of the peacock bass, were more than two orders of magnitude (307 times) less abundant in Gatun and one order of magnitude (28 times) less abundant in Alajuela than in Bayano. However, total native fish diversity did not differ significantly across lakes, suggesting that while many native species have declined in abundance, few have been completely extirpated. Introduced predators can have strong effects on community structure and functional diversity, even in highly diverse tropical communities, and these effects can persist over multiple decades.


Assuntos
Ecossistema , Peixes , Cadeia Alimentar , Comportamento Predatório , Animais , Lagos , Panamá
2.
J Evol Biol ; 27(6): 1093-104, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24750315

RESUMO

Adaptive radiation can be strongly influenced by interspecific competition for resources, which can lead to diverse outcomes ranging from competitive exclusion to character displacement. In each case, sympatric species are expected to evolve into distinct ecological niches, such as different food types, yet this expectation is not always met when such species are examined in nature. The most common hypotheses to account for the coexistence of species with substantial diet overlap rest on temporal variation in niches (often diets). Yet spatial variation in niche overlap might also be important, pointing to the need for spatiotemporal analyses of diet and diet overlap between closely related species persisting in sympatry. We here perform such an analysis by characterizing the diets of, and diet overlap among, four sympatric Darwin's ground finch species at three sites and over 5 years on a single Galápagos island (Santa Cruz). We find that the different species have broadly similar and overlapping diets - they are to some extent generalists and opportunists - yet we also find that each species retains some 'private' resources for which their morphologies are best suited. Importantly, use of these private resources increased considerably, and diet overlap decreased accordingly, when the availability of preferred shared foods, such as arthropods, was reduced during drought conditions. Spatial variation in food resources was also important. These results together suggest that the ground finches are 'imperfect generalists' that use overlapping resources under benign conditions (in space or time), but then retreat to resources for which they are best adapted during periods of food limitation. These conditions likely promote local and regional coexistence.


Assuntos
Adaptação Fisiológica , Dieta , Comportamento Alimentar , Tentilhões/fisiologia , Animais , Evolução Biológica , Comportamento Competitivo , Equador , Tentilhões/anatomia & histologia , Dinâmica Populacional , Simpatria
3.
Ginecol Obstet Mex ; 81(12): 738-42, 2013 Dec.
Artigo em Espanhol | MEDLINE | ID: mdl-24620529

RESUMO

Anomalous pulmonary venous connection is a rare pathology, both partial and total forms, according to the number of pulmonary veins draining into the left atrium, respectively. Total forms are classified into four groups, depending upon the anomalous connections to the systemic veins: supra, intracardiac or below, and finally a mixed form, the less frequent. Prenatal, even postnatal diagnose is difficult, especially in partial isolated forms. The association with chromosomal abnormalities is low, however is highly associated with complex heart malformations, especially total forms, often in the context of heterotaxy syndromes. We present a case of infracardiac APVC, in the context of complex heart disease, associated with complete atrioventricular canal and conotruncal anomaly, that came to surgery at 48 hours of life with poor outcome. We described the ultrasound and magnetic resonance angiography of this anomaly and its perinatal prognosis and management.


Assuntos
Angiografia por Ressonância Magnética/métodos , Veias Pulmonares/anormalidades , Ultrassonografia Pré-Natal/métodos , Adulto , Feminino , Humanos , Recém-Nascido , Masculino , Gravidez , Prognóstico , Veias Pulmonares/diagnóstico por imagem , Veias Pulmonares/cirurgia
4.
Integr Org Biol ; 5(1): obad025, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37521144

RESUMO

Evidence suggests that hurricanes can influence the evolution of organisms, with phenotypic traits involved in adhesion, such as the toepads of arboreal lizards, being particularly susceptible to natural selection imposed by hurricanes. To investigate this idea, we quantified trait variation before and after Hurricanes Irma and Maria (2017) in forest and urban populations of the Puerto Rican lizard Anolis cristatellus. We found that the hurricanes affected toe morphology differently between forest and urban sites. In particular, toepads of the forefeet were longer and narrower in forest, but wider in urban populations, compared to pre-hurricane measures. Toepads of the hind feet were larger in area following the hurricanes. Fore and rear toes increased in length following the hurricane. There were no changes in the number of lamellae scales or lamellae spacing, but lamellae 6-11 of the forefeet shifted proximally following the hurricane. We also measured clinging performance and toe shape. We found that toepad area and toe lengths were stronger predictors of adhesive forces than toepad shape. Our results highlight an interaction between urbanization and hurricanes, demonstrating the importance to consider how urban species will respond to extreme weather events. Additionally, our different results for fore and rear feet highlight the importance of evaluating both of these traits when measuring the morphological response to hurricanes in arboreal lizards.


La evidencia sugiere que los huracanes pueden influir en la evolución de los organismos, rasgos fenotípicos como las almohadillas distales de los lagartos arbóreos, son particularmente susceptibles a la selección natural impuesta por los huracanes. Para investigar esta idea, cuantificamos la variación de las almohadillas distales antes y después de los huracanes Irma y María (2017) en poblaciones de bosques y urbanas de las lagartijas puertorriqueña Anolis cristatellus. Encontramos que los cambios morfológicos luego de los huracanes variaron entre las poblaciones de bosque y urbanas. Para las poblaciones de bosque, las almohadillas de las patas delanteras eran más largas y estrechas luego de las tormentas. Por el contrario, las almohadillas delanteras de las poblaciones urbanas fueron más anchas luego de los huracanes. Las almohadillas de los pies traseros tenían un área más grande en todas las poblaciones luego de los huracanes. Los dedos delanteros y traseros aumentaron de longitud después del huracán. No hubo cambios en el número de escamas en las almohadillas distales ni en el ancho de estas escamas, pero las escamas 6­11 de las patas delanteras se desplazaron proximalmente después del huracán. También medimos las fuerzas adhesivas producida por las almohadillas distales para contrastar con la morfología de los dedos. Encontramos que el área de las almohadillas distales y la longitud de los dedos fueron los predictores más fuertes de las fuerzas adhesivas. Nuestros resultados destacan una interacción entre la urbanización y los huracanes, lo que demuestra la importancia de considerar cómo responderán las especies urbanas a los eventos climáticos extremos. Además, nuestros diferentes resultados para las patas delanteras y traseras resaltan la importancia de evaluar ambos rasgos al medir la respuesta morfológica a los huracanes en lagartijas arbóreos.

5.
Sci Total Environ ; 818: 151854, 2022 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-34826482

RESUMO

A recent paper by Beretta-Blanco and Carrasco-Letelier (2021) claims that agricultural eutrophication is not one of the main causes for cyanobacterial blooms in rivers and artificial reservoirs. By combining rivers of markedly different hydrological characteristics e.g., presence/absence and number of dams, river discharge and geological setting, the study speculates about the role of nutrients for modulating phytoplankton chlorophyll-a. Here, we identified serious flaws, from erratic and inaccurate data manipulation. The study did not define how erroneous original dataset values were treated, how the variables below the detection/quantification limit were numerically introduced, lack of mandatory variables for river studies such as flow and rainfall, arbitrary removal of pH > 7.5 values (which were not outliers), and finally how extreme values of other environmental variables were included. In addition, we identified conceptual and procedural mistakes such as biased construction/evaluation of model prediction capability. The study trained the model using pooled data from a short restricted lotic section of the (large) Uruguay River and from both lotic and reservoir domains of the Negro River, but then tested predictability within the (small) Cuareim River. Besides these methodological considerations, the article shows misinterpretations of the statistical correlation of cause and effect neglecting basic limnological knowledge of the ecology of harmful algal blooms (HABs) and international research on land use effects on freshwater quality. The argument that pH is a predictor variable for HABs neglects overwhelming basic paradigms of carbon fluxes and change in pH because of primary productivity. As a result, the article introduces the notion that HABs formation are not related to agricultural land use and water residence time and generate a great risk for the management of surface waterbodies. This reply also emphasizes the need for good practices of open data management, especially for public databases in view of external reproducibility.


Assuntos
Negro ou Afro-Americano , Rios , Monitoramento Ambiental , Eutrofização , Proliferação Nociva de Algas , Humanos , Fósforo/análise , Reprodutibilidade dos Testes , Uruguai
6.
J Mol Neurosci ; 68(4): 590-602, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31054091

RESUMO

Erythropoietin, a multitarget molecule exhibited neuroprotective properties, especially against cerebral ischemia. However, little effort has been made to determinate both the administration pathway and doses that diminishes neuronal damage. In this study, we investigate the effect on CA1 region of different intranasal doses of rHuEPO (500, 1000 and 2500 IU/kg) applied in distinct post-damage times (1, 6, and 24 h) against ischemic cellular damage. Furthermore, most effective dose and time were used to evaluate gen and protein expression changes in 3 key molecules (EPO, EPOR, and ßcR). We established that CA1-region present histopathological damage in this ischemia model and that rHuEPO protects cells against damage, particularly at 1000 IU dose. Molecular data shows that EPO and EPOR gene expression are upregulated in a short term after damage treatment with rHuEPO (1 h); oppositely, BcR is upregulated in ischemic and Isc + EPO. Protein expression data displays no changes on EPO expression in evaluated times after treatment, but a tendency to increase 24 h after damage; in the opposite way, EPOR is upregulated significantly 6 h after treatment and this effect last until 24 h. So, our data suggest that a single intranasal dose of rHuEPO (1 h post-injury) provides histological neurorestoration in CA1 hippocampal region, even if we did not observe a dose-dependent dose effect, the medium dose evaluated (1000 UI/kg of b.w.) was more effective and sufficient for induces molecular changes that provides a platform for neuroprotection.


Assuntos
Isquemia Encefálica/tratamento farmacológico , Região CA1 Hipocampal/efeitos dos fármacos , Eritropoetina/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Administração Intranasal , Animais , Região CA1 Hipocampal/metabolismo , Eritropoetina/administração & dosagem , Eritropoetina/farmacologia , Humanos , Masculino , Fármacos Neuroprotetores/administração & dosagem , Fármacos Neuroprotetores/farmacologia , Ratos , Ratos Wistar
7.
J Appl Microbiol ; 104(5): 1266-74, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18070038

RESUMO

AIMS: To investigate the antimicrobial properties of 6-oxophenolic triterpenoids isolated from Maytenus blepharodes against different micro-organisms and the mode of action on Bacillus subtilis. METHODS AND RESULTS: The activity of zeylasterone and demethylzeylasterone was evaluated by microdilution method. Zeylasterone showed a higher activity, being active against Gram-positive bacteria (minimum inhibitory concentration 3-20 microg ml(-1)) and Candida albicans (10 microg ml(-1)). Killing curves revealed a bacteriostatic effect on B. subtilis that was dependent on the growth phase and inoculum size. Zeylasterone caused cell membrane alterations in B. subtilis, as shown by potassium leakage and formation of mesosome-like structures. However, membrane disruption was not revealed by either LIVE/DEAD Baclight assay or measurement of intracellular constituent efflux. Zeylasterone showed an early effect on N-acetyl-glucosamine and uridine incorporation and later on that of thymidine and leucine. CONCLUSIONS: Diverse micro-organisms exhibit sensitivities towards compounds studied. The permeability changes in the cytoplasmic membrane and nonsimultaneous ceasing of macromolecular synthesis suggest that zeylasterone could act on multiple targets on B. subtilis. SIGNIFICANCE AND IMPACT OF THE STUDY: The activity showed against B. subtilis as a model of spore-forming bacteria would provide valuable information for further studies in the development of 6-oxophenolic triterpenoids as antiseptic and disinfectant properties.


Assuntos
Anti-Infecciosos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Triterpenos/farmacologia , Bacillus subtilis/metabolismo , Bacillus subtilis/ultraestrutura , Candida albicans/efeitos dos fármacos , Maytenus/metabolismo , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Peptidoglicano/metabolismo , RNA Bacteriano/biossíntese , Esporos Bacterianos/efeitos dos fármacos , Triterpenos/química , Triterpenos/isolamento & purificação
8.
J Appl Microbiol ; 104(3): 776-86, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17927739

RESUMO

AIMS: To evaluate the effectiveness of the optimized immunomagnetic separation (IMS)-plating protocol in relation to other culture, serological and molecular techniques currently used for Clavibacter michiganensis subsp. michiganensis in seed-testing laboratories. METHODS AND RESULTS: Bacterial suspensions, tomato seed extracts spiked with the pathogen and naturally infected seeds were IMS-plated for the detection of C. m. subsp. michiganensis. These results were compared with plating on general (YPGA) and semiselective (mSCM) media, double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), immunofluorescent assay (IF) or polymerase chain reaction (PCR). Different seed lots and pathogen strains were also tested. IMS-plating allowed the detection of less than 10 CFU ml(-1) of pathogen in all assayed samples. The mSCM medium provided positive results for 10 CFU ml(-1) in naturally infected seeds, but up to 14 days was necessary for the typical colonies of the target to be come visible. By serological techniques, 10(3) and up to 10(4) CFU ml(-1) were detected by IF and ELISA, respectively. DNA extraction was required to obtain positive results by PCR in seed extracts containing 10(3) CFU ml(-1) or more. CONCLUSIONS: Among the evaluated methods, IMS-plating provided the best results regarding sensitivity and specificity for C. m. subsp. michiganensis detection, allowing the recovery of viable bacteria from seed extracts. SIGNIFICANCE AND IMPACT OF THE STUDY: IMS-plating increases isolation rates of C. m. subsp. michiganensis and could improve standard protocols currently used for routine analysis.


Assuntos
Infecções Bacterianas/microbiologia , Microbiologia de Alimentos , Micrococcaceae/isolamento & purificação , Doenças das Plantas/microbiologia , Solanum lycopersicum , DNA/análise , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , Separação Imunomagnética , Reação em Cadeia da Polimerase , Sementes/microbiologia
9.
J Microbiol Methods ; 67(1): 141-9, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16631265

RESUMO

The use of pathogen-free plant material is the main strategy for controlling bacterial canker of tomato caused by Clavibacter michiganensis subsp. michiganensis. However, detection and isolation of this pathogen from seeds before field or greenhouse cultivation is difficult when the bacterium is at low concentration and associated microbiota are present. Immunomagnetic separation (IMS), based on the use of immunomagnetic beads (IMBs) coated with specific antibodies, was used to capture C. michiganensis subsp. michiganensis cells, allowing removal of non-target bacteria from samples before plating on non-selective medium. Different concentrations of IMBs and of two antisera were tested, showing that IMS with 10(6)IMBs/ml coated with a polyclonal antiserum at 1/3200 dilution recovered more than 50% of target cells from initial inocula of 10(3) to 10(0)CFU/ml. Threshold detection was lower than 10CFU/ml even in seed extracts containing seed debris and high populations of non-target bacteria. The IMS permitted C. michiganensis subsp. michiganensis isolation from naturally infected seeds with higher sensitivity and faster than direct isolation on the semiselective medium currently used and could become a simple viable system for routinely testing tomato seed lots in phytosanitary diagnostic laboratories.


Assuntos
Actinomycetales/isolamento & purificação , Separação Imunomagnética/métodos , Doenças das Plantas/microbiologia , Solanum lycopersicum/microbiologia , Sementes/microbiologia
10.
Biochim Biophys Acta ; 517(2): 349-59, 1978 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-626742

RESUMO

The presumptive messenger RNAs for type I procollagen were isolated from chick embryo calvaria at various stages of development. Poly(A)-containing RNA fractions from denaturing sucrose gradients directed protein synthesis in a cell-free system derived from wheat germ. Procollagen mRNA activity was detected in a region of about 26 S. Approx. 80% of the labeled proline incorporated into cell-free product was susceptible to digestion by purified bacterial collagenase. The synthesis of procollagen mRNAs was followed during development. Comparison of the in vitro labeled mRNAs from calvaria of day 12--16 embryos indicated that the 26 S component was most pronounced at day 13 and decreased progressively towards day 16. In addition, incubation of calvaria with tritiated nucleosides for 1.5--25 h revealed that 26 S mRNA was significantly labeled only after prolonged periods. The results suggest that procollagen mRNA is a relatively stable species with a prolonged half-life compared to the majority of mRNAs in this tissue.


Assuntos
Osso e Ossos/metabolismo , Pró-Colágeno/genética , RNA Mensageiro/biossíntese , Animais , Osso e Ossos/embriologia , Sistema Livre de Células , Embrião de Galinha , Técnicas de Cultura , Poli A/metabolismo , Pró-Colágeno/biossíntese , RNA Mensageiro/isolamento & purificação
11.
Methods Find Exp Clin Pharmacol ; 27(5): 317-22, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16082419

RESUMO

The evolution of treatment of chronic hepatitis C virus infection has led to improved therapeutic efficacy. However, a major problem is the presence of side effects that require modification or withdrawal of drug therapy in 15-20% of cases. This could potentially influence the lack of sustained viral response in 50% of the cases. Side effects are common, even with pegylated interferon. This study aimed to assess the incidence and severity of infections based on the development of neutropenia associated with combined therapy with pegylated interferon-alpha2a plus ribavirin in 209 patients with chronic hepatitis C infection. All patients were administered pegylated interferon-alpha2a (180 microg/week) plus ribavirin (800 mg/day for 24 weeks in cases of nongenotype 1, or 1000-1200 mg/day for 48 weeks for genotype 1, according to whether patients weighed more or less than 75 kg). Patients with preexisting neutropenia of any cause or cirrhosis were excluded. Neutropenia was defined as a neutrophil count (NC) of <1500 cells/microl. Neutropenia was classified into three levels during treatment: 750

Assuntos
Antivirais/efeitos adversos , Hepatite C Crônica/complicações , Interferon-alfa/efeitos adversos , Neutropenia/induzido quimicamente , Ribavirina/efeitos adversos , Adulto , Idoso , Antivirais/uso terapêutico , Quimioterapia Combinada , Feminino , Hepatite C Crônica/tratamento farmacológico , Humanos , Interferon alfa-2 , Interferon-alfa/uso terapêutico , Contagem de Leucócitos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Neutropenia/patologia , Polietilenoglicóis , Proteínas Recombinantes , Ribavirina/uso terapêutico
12.
Int J Dev Biol ; 41(1): 91-102, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9074941

RESUMO

The present study was performed to determine whether mammalian TGF-beta isoforms and Xenopus TGF-beta 5 elicit a differential chondrogenic response on mesenchymal cells during mouse limb development. Results showed that TGF-beta isoforms produced a distinct chondrogenic pattern depending on embryonic stage. When they were applied to 5 day micromass cultures of limb mesenchymal cells from embryonic stages 19, 20 and 21, a differential response to all four TGF-beta isoforms assayed was observed. By stage 19 the cells formed a uniform sheet of cartilage cells; by stage 20, mesenchymal cells were more responsive to TGF-beta 1 and TGF-beta 5 than at stages 19 and 21, showing an entire cell layer of chondrogenic cells with higher accumulation of extracellular matrix. The diminished effect of TGF-beta 2 and TGF-beta 3 at stages 20 and 21 was accompanied by a nodular pattern of chondrogenic cells rather than by a uniform sheet, as seen at stage 19. At stage 20 TGF-beta 1 and TGF-beta 5 enhanced the expression of sulfated proteoglycans, type II collagen, cartilage link protein and alkaline phosphatase activity. In contrast, TGF-beta 2 and TGF-beta 3 caused less expression in the same parameters. Only a transient exposure to TGF-beta isoforms at days 1 and 2 of culture stimulate chondrogenesis, indicating that TGF-beta isoforms could regulate chondrogenesis at early stages of chondrocyte differentiation. However, when TGF-beta isoforms were applied to low density cultures of mesenchymal cells, chondrogenesis was enhanced only by 25%, suggesting that TGF-beta isoforms enhanced cartilage differentiation to higher levels in micromass cultures than in situations in which little or no chondrogenic differentiation normally occurs.


Assuntos
Cartilagem/embriologia , Proteínas da Matriz Extracelular , Extremidades/embriologia , Fator de Crescimento Transformador beta/fisiologia , Fosfatase Alcalina/metabolismo , Animais , Colágeno/metabolismo , Matriz Extracelular/metabolismo , Feminino , Idade Gestacional , Masculino , Mesoderma/citologia , Camundongos , Camundongos Endogâmicos BALB C , Proteínas/metabolismo , Proteoglicanas/metabolismo , Sulfatos/metabolismo , Xenopus laevis
13.
Int J Dev Biol ; 43(1): 59-67, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10213083

RESUMO

Cell surface adhesion and extracellular matrix proteins are known to play a key role in the formation of cell condensations during skeletal development, and their formation is crucial for the expression of cartilage-specific genes. However, little is known about the relationship between adhesion molecules (N-cadherin and N-CAM), extracellular matrix proteins (fibronectin and tenascin) and TGF-beta1, TGF-beta2 and TGF-beta3 during in vitro precartilage condensations in mouse chondrogenesis. On these bases, we determined the participation of mammalian TGF-beta1, TGF-beta2 and TFG-beta3 and Xenopus TGF-beta5 on the expression of cell surface adhesion and extracellular matrix proteins during the formation of precartilage condensations. Also, we characterized the effects of TGF-betas on proteoglycan metabolism at different cellular densities in mouse embryonic limb bud mesenchymal cells. In TGF-beta1 and TGF-beta5-treated cultures, proteoglycan biosynthesis was higher than in controls, while there were no differences in proteoglycan catabolism, which caused the accumulation of cartilage extracellular matrix. When mesenchymal cells were seeded at three different cellular densities in the presence of TGF-betas, only high density cultures presented increased stimulation of proteoglycan biosynthesis, compared to low and intermediate densities. To determine whether the effect of TGF-betas on precartilage condensations is mediated through the expression of N-cadherin, N-CAM, fibronectin and tenascin, we evaluated their expression. Results showed that TGF-beta1, TGF-beta2, TGF-beta3, and TGF-beta5 differentially enhanced the expression of N-cadherin, N-CAM, fibronectin and tenascin in precartilage condensations, suggesting that TGF-beta isoforms play an important role in the establishment of cell-cell and cell-extracellular matrix interactions during precartilage condensations.


Assuntos
Caderinas/metabolismo , Cartilagem/embriologia , Moléculas de Adesão Celular/metabolismo , Fibronectinas/metabolismo , Mesoderma/metabolismo , Tenascina/metabolismo , Fator de Crescimento Transformador beta/farmacologia , Animais , Western Blotting , Células Cultivadas , Relação Dose-Resposta a Droga , Imunofluorescência , Glicosaminoglicanos/biossíntese , Mesoderma/citologia , Camundongos , Camundongos Endogâmicos BALB C , Proteoglicanas/biossíntese , Fatores de Tempo
14.
Cell Calcium ; 22(1): 31-8, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9232350

RESUMO

Maitotoxin (MTX), a water-soluble polyether obtained from the marine dinoflagellate Gambierdiscus toxicus increased intracellular calcium in a concentration-dependent manner in fibroblasts obtained from human skin. The effect of this toxin was both saturable and of high affinity, showing an apparent half activation constant of 450 fM. The toxin did not release intracellular calcium storage compartments nor did the release of these compartments with thapsigargin or ionomycin affect the toxin response. The toxin effect was reduced significantly by pre-incubating the cells with 0.1% trypsin for 30 min, strongly suggesting that the toxin receptor is a plasmalemmal protein. The effect of MTX was partially inhibited by diphenoxylate.


Assuntos
Cálcio/metabolismo , Toxinas Marinhas/farmacologia , Oxocinas , Pele/metabolismo , Compartimento Celular , Membrana Celular/química , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Difenoxilato/farmacologia , Relação Dose-Resposta a Droga , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Proteínas de Membrana/efeitos dos fármacos , Proteínas de Membrana/metabolismo , Pele/citologia , Pele/efeitos dos fármacos , Tripsina/farmacologia
15.
J Invest Dermatol ; 111(5): 828-34, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9804346

RESUMO

We evaluated the in situ expression of adhesion molecules (E-selectin and vascular cell-adhesion molecule) and proinflammatory/fibrogenic cytokines (IL-1beta, TNF-alpha, TGF-beta1, and PDGF) in sections of normal skin, hypertrophic scar, and hypertrophic scar previously treated with an irradiated mixture of collagen-polyvinylpyrrolidone and completely resolved. Expression of these proteins was detected by indirect immunoperoxidase staining. The hypertrophic scar group displayed an increased amount of IL-1beta, TNF-alpha, TGF-beta1, and PDGF compared with the normal skin and treated scar groups. Values were statistically significant when cytokines in hypertrophic scar and hypertrophic treated sections were compared. Surprisingly, no differences were detected between normal skin and treated scars. On the other hand, differences in levels of E-selectin and vascular cell-adhesion molecule were not statistically significant between the groups, except for vascular cell-adhesion molecule, which decreased in treated scars. Also, supernatants from fibroblast cultures derived from treated hypertrophic scar, showed a reduction in TGF-beta1 and PDGF expression, although apparently collagen synthesis was not affected. Based on previous data from clinical studies in human dermal fibrosis remodeling, and the results presented here, we suggest that collagen-polyvinylpyrrolidone modulates extracellular matrix turnover, mainly of collagen, because expression levels of IL-1beta, TNF-alpha, TGF-beta1, and PDGF were diminished. We infer that collagen-polyvinylpyrrolidone participation could also modify the inflammatory process observed in hypertrophic scarring, by diminishing the expression of adhesion molecules, as a consequence of lower levels of proinflammatory cytokines, mainly IL-1beta and TNF-alpha.


Assuntos
Cicatriz Hipertrófica/metabolismo , Colágeno/fisiologia , Citocinas/biossíntese , Povidona/farmacologia , Adolescente , Adulto , Moléculas de Adesão Celular/biossíntese , Criança , Colágeno/metabolismo , Meios de Cultura/química , Regulação para Baixo , Selectina E/biossíntese , Feminino , Fibroblastos/citologia , Humanos , Interleucina-1/biossíntese , Masculino , Fator de Crescimento Derivado de Plaquetas/biossíntese , Pele/metabolismo , Fator de Crescimento Transformador beta/biossíntese , Fator de Necrose Tumoral alfa/biossíntese , Molécula 1 de Adesão de Célula Vascular/biossíntese
16.
Neuroscience ; 129(3): 647-53, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15541886

RESUMO

We explored the contribution of different calcium channel types to the long-term potentiation (LTP) of superior cervical ganglion of the rat. Right after a conditioning train of 40 Hz for 5 s, the maximum amplitude of the postsynaptic response (maximum potentiation) increased 5.6+/-0.5-fold. Potentiation decreased to 20% of its initial value within the following 70.0+/-8.0 min (LTP decay time). The contribution of P/Q-, N- and L-type calcium channels to LTP was studied by blocking their activity with synthetic funnel-web spider toxin (10 or 100 microM), omega-conotoxin GVIA (5 microM) or nifedipine (10 microM), respectively. The three blockers reduced the amplitude of the postsynaptic compound action potential before the conditioning train. After the train, all of the toxins reduced the LTP decay time and the integral of the amplitude versus time curve, defined as the LTP extent. In addition, all three blockers increased the maximum potentiation. Our results demonstrate that different calcium channel types contribute to ganglionic LTP. These effects may be by coupling excitation-secretion from different types of synaptic vesicles.


Assuntos
Canais de Cálcio/fisiologia , Potenciação de Longa Duração/fisiologia , Neurônios/fisiologia , Gânglio Cervical Superior/citologia , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/classificação , Canais de Cálcio/efeitos dos fármacos , Relação Dose-Resposta a Droga , Estimulação Elétrica/métodos , Técnicas In Vitro , Potenciação de Longa Duração/efeitos dos fármacos , Potenciação de Longa Duração/efeitos da radiação , Masculino , Modelos Neurológicos , Neurônios/efeitos dos fármacos , Neurônios/efeitos da radiação , Ratos , Ratos Wistar , Transmissão Sináptica/efeitos dos fármacos , Fatores de Tempo
17.
Biochem Pharmacol ; 52(2): 289-99, 1996 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-8694854

RESUMO

Previous results of our group revealed that mebendazole, a broad spectrum anthelmintic drug with antimicrotubular properties, used for the treatment of liver cirrhosis, decreased total collagen content and biosynthesis in liver upon treatment. In the present study, we have evaluated the effects of mebendazole (5-50 micrograms/mL) on protein synthesis, secretion, and deposition in human-derived fibroblast cultures. The results showed a decrease in cell viability (18.5 +/- 0.9%) at 50 micrograms/mL. [3H]Thymidine incorporation diminished gradually with increasing mebendazole concentrations, reaching a plateau (53.67%) between 30 and 50 micrograms/mL. In late logarithmic phase cultures, the drug caused a decrease of [3H]proline incorporation (43.10%) and collagen biosynthesis (58.61%) in the extracellular matrix. This correlated with an increase in radioactivity in total proteins (51.28%) of the intracellular fraction. Similar results were obtained when mebendazole was assayed in post-confluent fibroblast cultures. The electrophoretic patterns of the extracellular matrix showed a decrease of radioactive collagenous components (alpha chains and beta dimers). By contrast, in the intracellular fraction an increase of radioactive collagen precursors (pro alpha chains) was observed. Immunofluorescence studies and immunotransfer analysis, using polyclonal anti-type I collagen antibodies, revealed an accumulation of intracellular collagen which included: collagen pro alpha chains, alpha chains, and low molecular weight peptides. The results obtained suggest that mebendazole interferes with the transcellular mobilization of proteins, resulting in a decrease of secretion and deposition of extracellular matrix proteins, and an accumulation of intracellular collagenous components. The intracellular accumulation of newly synthesized proteins could cause a feedback regulation in fibroblast cultures.


Assuntos
Antinematódeos/farmacologia , Proteínas da Matriz Extracelular/biossíntese , Mebendazol/farmacologia , Proteínas dos Microtúbulos/biossíntese , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas/efeitos dos fármacos , Células Cultivadas/metabolismo , Colágeno/biossíntese , Eletroforese em Gel de Poliacrilamida , Proteínas da Matriz Extracelular/metabolismo , Fibronectinas/análise , Imunofluorescência , Humanos , Proteínas dos Microtúbulos/metabolismo , Prolina/metabolismo , Trítio
18.
Am J Med Genet ; 25(1): 85-98, 1986 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3099574

RESUMO

The association between cryptophthalmos and multiple congenital malformations has been well documented over the last century. Numerous authors have described cases as the cryptophthalmos syndrome, but recently reports of cases without cryptophthalmos have led several authors to use the eponymic designation Fraser syndrome. We have seen seven cases of cryptophthalmos syndrome, including three sib pairs. All presented with cryptophthalmos and bilateral renal agenesis in addition to other characteristic associated malformations. A literature review showed 124 cases in which 27 demonstrated isolated cryptophthalmos, while 97 showed a pattern of multiple congenital malformations. We selected four major and eight minor criteria which enabled us to classify 86 of those cases as having cryptophthalmos syndrome with 11 remaining unclassified. Cryptophthalmos demonstrates equal sex distribution, occurrence in sibs, consanguinity in families with more than one affected child, and lack of vertical transmission--strongly suggesting autosomal recessive inheritance. Isolated cryptophthalmos or cryptophthalmos sequence was sporadic in 16 cases and familial in 11. The familial cases occurred in three families and demonstrated vertical transmission. The pathogenesis of this syndrome is unknown. There are similarities to animal models of maternal vitamin A deprivation and defects in programmed cell death. Cryptophthalmos syndrome should be considered in the differential diagnosis of cases with multiple congenital malformations, especially when they are associated with renal agenesis, even in the absence of cryptophthalmos.


Assuntos
Anormalidades Múltiplas/genética , Anormalidades do Olho , Diagnóstico Diferencial , Feminino , Genes Recessivos , Humanos , Recém-Nascido , Rim/anormalidades , Masculino , Síndrome
19.
Bone Marrow Transplant ; 24(9): 1029-31, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10556964

RESUMO

A 24-year-old woman with CML underwent allogeneic BMT in August 1995 from a one-antigen HLA mismatched brother. Conditioning included BuCy2 and CsA and MTX were used to prevent GVHD. In July 1997 she developed right leg pain, lytic bone lesions of distal femur and a solid mass of soft tissue. Histological diagnosis of malignant fibrous histiocytoma was made. Despite treatment with surgery and chemotherapy (doxorubicin and ifosfamide), the patient died 1 year later with local recurrence of the tumor and liver, lung and brain metastases. The CML was in CR.


Assuntos
Transplante de Medula Óssea/efeitos adversos , Histiocitoma Fibroso Benigno/etiologia , Leucemia Mieloide de Fase Crônica/terapia , Segunda Neoplasia Primária/etiologia , Adulto , Feminino , Neoplasias Femorais/diagnóstico , Neoplasias Femorais/etiologia , Histiocitoma Fibroso Benigno/diagnóstico , Humanos , Masculino , Segunda Neoplasia Primária/diagnóstico , Neoplasias de Tecidos Moles/diagnóstico , Neoplasias de Tecidos Moles/etiologia , Transplante Homólogo
20.
Brain Res Bull ; 16(3): 309-14, 1986 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2423199

RESUMO

In order to determine the molecular weight of the Luteinizing Hormone Releasing Hormone (LHRH) precursor, poly(A)-RNA from rat hypothalami and human placenta were translated in two mRNA dependent cell free translation systems. Total translation products were immunoprecipitated with two antisera that recognized LHRH high molecular weight forms. After SDS-polyacrylamide slab gel electrophoretic analysis of the immunoprecipitated material and fluorography, we detected in both tissues a protein of 50,000 daltons with the No. 1076 antiserum. This peptide was not immunoprecipitated by the No. 743 anti-LHRH antiserum or by non-immune rabbit serum. However, this protein was not displaced by excess LHRH added during the immunoprecipitation and seemed to be present in species where LHRH has not been reported. These data demonstrated that the LHRH mRNA is present in very low amounts in hypothalamus or placenta and that the sensitivity of the assay is not high enough to recognize it.


Assuntos
Hormônio Liberador de Gonadotropina/biossíntese , Hipotálamo/metabolismo , Placenta/metabolismo , Animais , Sistema Livre de Células , Eletroforese em Gel de Poliacrilamida , Feminino , Humanos , Técnicas Imunológicas , Masculino , Peso Molecular , Gravidez , Biossíntese de Proteínas , RNA/genética , Ratos , Ratos Endogâmicos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA