Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Mol Ther Methods Clin Dev ; 29: 513-521, 2023 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-37287748

RESUMO

The current Medicaid system is ill equipped to handle the anticipated approvals of new gene and cell therapy products. These advanced therapies tend to be single-dose, potentially durable options for a variety of indications spanning oncology, rare disease, and more. The up-front cost of these therapies contrasts with chronic care treatment, which may incur cost over the life of a patient. The cost of these innovative treatments, along with the anticipated larger patient pools, can limit patient access as Medicaid programs operate on limited or fixed budgets. Given the value of these therapies for diseases that may have large Medicaid populations, the system will need to grapple with the existing barriers to access to ensure equitable patient care. This review focuses on one such barrier, discrepancies between product indications and state Medicaid and Medicaid Managed Care Organization coverage policies, and it proposes federal policy solutions to this barrier to better accommodate the exponential growth of the gene and cell therapy pipeline.

2.
Curr Biol ; 33(6): R215-R216, 2023 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-36977379

RESUMO

Successful sexual reproduction relies on the coordination of multiple biological systems, yet traditional concepts of biological sex often ignore the natural plasticity in morphology and physiology underlying sex. Most female mammals develop a patent (i.e., opened) vaginal entrance (introitus) prenatally or postnatally before or during puberty, usually under the influence of estrogens, and remain patent for the remainder of their lifespan1. An exception is the southern African giant pouched rat (Cricetomys ansorgei), whose vaginal introitus remains sealed well into adulthood2. Here, we explore this phenomenon and report that the reproductive organs and the vaginal introitus can undergo astounding and reversible transformation. Non-patency is characterized by reduced uterine size and the presence of a sealed vaginal introitus. Furthermore, the female urine metabolome shows that patent and non-patent females profoundly differ in their urine content, a reflection of differences in physiology and metabolism. Surprisingly, patency state did not predict fecal estradiol or progesterone metabolite concentrations. Exploring the plasticity that exists in reproductive anatomy and physiology can uncover that traits long considered 'fixed' in adulthood can become plastic under specific evolutionary pressures. Moreover, the barriers to reproduction that such plasticity creates present unique challenges to maximizing reproductive potential.


Assuntos
Estrogênios , Reprodução , Animais , Feminino , Muridae , Estradiol , Evolução Biológica
4.
Toxicon ; 163: 48-58, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30880189

RESUMO

Indospicine is a natural toxin occurring only in Indigofera plant species, including the Australian native species I. linnaei. These perennial legumes are resistant to drought and palatable to grazing livestock including cattle. Indospicine accumulates in the tissues (including muscle) of animals grazing Indigofera and these residues persist for several months after exposure. Dogs are particularly sensitive to indospicine with reports in past decades of hepatotoxicosis and mortalities in dogs after dietary exposure to indospicine-contaminated horse and camel meat. The risk for human consumption is not known, and the current study was undertaken to assess indospicine levels in cattle going to slaughter from divergent regions of Western Australia, and to predict the likelihood of significant residues being present. Muscle and corresponding liver samples from 776 cattle originating from the Kimberley and Pilbara Regions in the tropical north of the state, where I. linnaei is prevalent, and 640 cattle from the South West and South Coast Regions in the temperate south west of the state, where the plant is not known to occur, were collected at abattoirs over four seasons in 2015-2017. Indospicine levels were measured by LC-MS/MS and ranged from below detection to 3.63 mg/kg. No indospicine residues were detected in any of the animals originating from the South West and South Coast Regions. Prevalence of indospicine residues in cattle from the Kimberley Region was as high as 33% in spring and 91% in autumn, with positive animals being present in most consignments and on most properties. The average prevalence of indospicine residues from the Kimberley and Pilbara Regions throughout the survey period was 63%. @Risk best fit probability distributions showed ninety-fifth percentile (P95) indospicine concentrations of 0.54 mg/kg for muscle and 0.77 mg/kg for liver in cattle originating from the Kimberley and Pilbara Regions during the survey period. When considered with average Australian meat consumption data, the estimated consumer exposure from this P95 muscle was 0.32 µg indospicine/kg bw/day, which compared favourably with our calculated provisional tolerable daily intake (PTDI) of 1.3 µg indospicine/kg bw/day. However canine exposure is of potential concern, with active working dog exposure calculated to exceed this PTDI by a factor of 25, based on a P95 indospicine concentration of 0.54 mg/kg in muscle.


Assuntos
Bovinos , Fígado/química , Músculo Esquelético/química , Norleucina/análogos & derivados , Animais , Dieta/veterinária , Cães , Contaminação de Alimentos/análise , Humanos , Indigofera , Norleucina/análise , Norleucina/toxicidade , Plantas Tóxicas , Carne Vermelha/análise , Medição de Risco , Estações do Ano , Toxinas Biológicas/análise , Austrália Ocidental
5.
Inorg Chem ; 58(6): 3838-3850, 2019 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-30799613

RESUMO

The chemical accessibility of the CeIV oxidation state enables redox chemistry to be performed on the naturally coinage-metal-deficient phases CeM1- xSO (M = Cu, Ag). A metastable black compound with the PbFCl structure type (space group P4/ nmm: a = 3.8396(1) Å, c = 6.607(4) Å, V = 97.40(6) Å3) and a composition approaching CeSO is obtained by deintercalation of Ag from CeAg0.8SO. High-resolution transmission electron microscopy reveals the presence of large defect-free regions in CeSO, but stacking faults are also evident which can be incorporated into a quantitative model to account for the severe peak anisotropy evident in all the high-resolution X-ray and neutron diffractograms of bulk CeSO samples; these suggest that a few percent of residual Ag remains. A straw-colored compound with the filled PbFCl (i.e., ZrSiCuAs- or HfCuSi2-type) structure (space group P4/ nmm: a = 3.98171(1) Å, c = 8.70913(5) Å, V = 138.075(1) Å3) and a composition close to LiCeSO, but with small amounts of residual Ag, is obtained by direct reductive lithiation of CeAg0.8SO or by insertion of Li into CeSO using chemical or electrochemical means. Computation of the band structure of pure, stoichiometric CeSO predicts it to be a Ce4+ compound with the 4f-states lying approximately 1 eV above the sulfide-dominated valence band maximum. Accordingly, the effective magnetic moment per Ce ion measured in the CeSO samples is much reduced from the value found for the Ce3+-containing LiCeSO, and the residual paramagnetism corresponds to the Ce3+ ions remaining due to the presence of residual Ag, which presumably reflects the difficulty of stabilizing Ce4+ in the presence of sulfide (S2-). Comparison of the behavior of CeCu0.8SO with that of CeAg0.8SO reveals much slower reaction kinetics associated with the Cu1- xS layers, and this enables intermediate CeCu1- xLi xSO phases to be isolated.

6.
PLoS One ; 11(9): e0161500, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27583459

RESUMO

Substantial gains in muscle strength and hypertrophy are clearly associated with the routine performance of resistance training. What is less evident is the optimal timing of the resistance training stimulus to elicit these significant functional and structural skeletal muscle changes. Therefore, this investigation determined the impact of a single bout of resistance training performed either in the morning or evening upon acute anabolic signalling (insulin-like growth factor-binding protein-3 (IGFBP-3), myogenic index and differentiation) and catabolic processes (cortisol). Twenty-four male participants (age 21.4±1.9yrs, mass 83.7±13.7kg) with no sustained resistance training experience were allocated to a resistance exercise group (REP). Sixteen of the 24 participants were randomly selected to perform an additional non-exercising control group (CP) protocol. REP performed two bouts of resistance exercise (80% 1RM) in the morning (AM: 0800 hrs) and evening (PM: 1800 hrs), with the sessions separated by a minimum of 72 hours. Venous blood was collected immediately prior to, and 5 min after, each resistance exercise and control sessions. Serum cortisol and IGFBP-3 levels, myogenic index, myotube width, were determined at each sampling period. All data are reported as mean ± SEM, statistical significance was set at P≤0.05. As expected a significant reduction in evening cortisol concentration was observed at pre (AM: 98.4±10.5, PM: 49.8±4.4 ng/ml, P<0.001) and post (AM: 98.0±9.0, PM: 52.7±6.0 ng/ml, P<0.001) exercise. Interestingly, individual cortisol differences pre vs post exercise indicate a time-of-day effect (AM difference: -2±2.6%, PM difference: 14.0±6.7%, P = 0.03). A time-of-day related elevation in serum IGFBP-3 (AM: 3274.9 ± 345.2, PM: 3605.1 ± 367.5, p = 0.032) was also evident. Pre exercise myogenic index (AM: 8.0±0.6%, PM: 16.8±1.1%) and myotube width (AM: 48.0±3.0, PM: 71.6±1.9 µm) were significantly elevated (P<0.001) in the evening. Post exercise myogenic index was greater AM (11.5±1.6%) compared with PM (4.6±0.9%). No difference was observed in myotube width (AM: 48.5±1.5, PM: 47.8±1.8 µm) (P>0.05). Timing of resistance training regimen in the evening appears to augment some markers of hypertrophic potential, with elevated IGFBP-3, suppressed cortisol and a superior cellular environment. Further investigation, to further elucidate the time course of peak anabolic signalling in morning vs evening training conditions, are timely.


Assuntos
Ritmo Circadiano/fisiologia , Hidrocortisona/sangue , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Músculo Esquelético/fisiologia , Treinamento Resistido , Adulto , Linhagem Celular , Ensaio de Imunoadsorção Enzimática , Humanos , Hipertrofia , Masculino , Músculo Esquelético/metabolismo , Cooperação do Paciente , Adulto Jovem
7.
Proc Natl Acad Sci U S A ; 112(41): E5600-7, 2015 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-26401017

RESUMO

We previously computed that genes with de novo (DN) likely gene-disruptive (LGD) mutations in children with autism spectrum disorders (ASD) have high vulnerability: disruptive mutations in many of these genes, the vulnerable autism genes, will have a high likelihood of resulting in ASD. Because individuals with ASD have lower fecundity, such mutations in autism genes would be under strong negative selection pressure. An immediate prediction is that these genes will have a lower LGD load than typical genes in the human gene pool. We confirm this hypothesis in an explicit test by measuring the load of disruptive mutations in whole-exome sequence databases from two cohorts. We use information about mutational load to show that lower and higher intelligence quotients (IQ) affected individuals can be distinguished by the mutational load in their respective gene targets, as well as to help prioritize gene targets by their likelihood of being autism genes. Moreover, we demonstrate that transmission of rare disruptions in genes with a lower LGD load occurs more often to affected offspring; we show transmission originates most often from the mother, and transmission of such variants is seen more often in offspring with lower IQ. A surprising proportion of transmission of these rare events comes from genes expressed in the embryonic brain that show sharply reduced expression shortly after birth.


Assuntos
Transtorno Autístico/genética , Bases de Dados Genéticas , Exoma , Pool Gênico , Modelos Genéticos , Mutação , Criança , Pré-Escolar , Feminino , Humanos , Masculino
8.
Phys Chem Chem Phys ; 16(39): 21016-31, 2014 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-24832683

RESUMO

The use of a density functional theory methodology with on-site corrections (DFT + U) has been repeatedly shown to give an improved description of localised d and f states over those predicted with a standard DFT approach. However, the localisation of electrons also carries with it the problem of metastability, due to the possible occupation of different orbitals and different locations. This study details the use of an occupation matrix control methodology for simulating localised d and f states with a plane-wave DFT + U approach which allows the user to control both the site and orbital localisation. This approach is tested for orbital occupation using octahedral and tetrahedral Ti(iii) and Ce(iii) carbonyl clusters and for orbital and site location using the periodic systems anatase-TiO2 and CeO2. The periodic cells are tested by the addition of an electron and through the formation of a neutral oxygen vacancy (leaving two electrons to localise). These test systems allow the successful study of orbital degeneracies, the presence of metastable states and the importance of controlling the site of localisation within the cell, and it highlights the use an occupation matrix control methodology can have in electronic structure calculations.

9.
J Agric Food Chem ; 62(30): 7345-54, 2014 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-24724702

RESUMO

Many plants worldwide contain monofluoroacetate and cause sudden death in livestock. These plants are primarily found in the southern continents of Africa, Australia, and South America, where they negatively affect livestock production. This review highlights past and current research investigating (1) the plants reported to contain monofluoroacetate and cause sudden death; (2) the mode of action, clinical signs, and pathology associated with poisoning by monofluoroacetate-containing plants; (3) chemical methods for the analysis of monofluoroacetate in plants; (4) the coevolution of native flora and fauna in Western Australia with respect to monofluoroacetate-containing plants; and (5) methods to mitigate livestock losses caused by monofluoroacetate-containing plants.


Assuntos
Fluoracetatos/toxicidade , Intoxicação por Plantas/veterinária , Plantas Tóxicas/química , Animais , Fluoracetatos/análise , Gado , Intoxicação por Plantas/prevenção & controle , Plantas Tóxicas/classificação , Plantas Tóxicas/toxicidade
10.
J Nat Prod ; 76(10): 1984-8, 2013 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-24053110

RESUMO

Legumes belonging to the Astragalus, Oxytropis, and Swainsona genera have been noted by ranchers in the Americas, Asia, and Australia to cause a neurologic disease often referred to as locoism or peastruck. The toxin in these legumes is swainsonine, an α-mannosidase and mannosidase II inhibitor. Recent research has shown that in Astragalus and Oxytropis species swainsonine is produced by a fungal endophyte belonging to the Undifilum genus. Here Swainsona canescens is shown to harbor an endophyte that is closely related to Undifilum species previously cultured from locoweeds of North America and Asia. The endophyte produces swainsonine in vitro and was detected by PCR and culturing in S. canescens. The endophyte isolated from S. canescens was characterized as an Undifilum species using morphological and phylogenetic analyses.


Assuntos
Alcaloides/isolamento & purificação , Fabaceae/química , Swainsonina/farmacologia , Alcaloides/análise , Alcaloides/química , Alcaloides/farmacologia , Endófitos/química , Fabaceae/genética , Manosidases/antagonistas & inibidores , Estrutura Molecular , Oxytropis/química , Análise de Sequência de DNA , Swainsonina/análise , Swainsonina/química
11.
Genome Res ; 23(12): 1985-95, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24026177

RESUMO

Selective breeding of dogs by humans has generated extraordinary diversity in body size. A number of multibreed analyses have been undertaken to identify the genetic basis of this diversity. We analyzed four loci discovered in a previous genome-wide association study that used 60,968 SNPs to identify size-associated genomic intervals, which were too large to assign causative roles to genes. First, we performed fine-mapping to define critical intervals that included the candidate genes GHR, HMGA2, SMAD2, and STC2, identifying five highly associated markers at the four loci. We hypothesize that three of the variants are likely to be causative. We then genotyped each marker, together with previously reported size-associated variants in the IGF1 and IGF1R genes, on a panel of 500 domestic dogs from 93 breeds, and identified the ancestral allele by genotyping the same markers on 30 wild canids. We observed that the derived alleles at all markers correlated with reduced body size, and smaller dogs are more likely to carry derived alleles at multiple markers. However, breeds are not generally fixed at all markers; multiple combinations of genotypes are found within most breeds. Finally, we show that 46%-52.5% of the variance in body size of dog breeds can be explained by seven markers in proximity to exceptional candidate genes. Among breeds with standard weights <41 kg (90 lb), the genotypes accounted for 64.3% of variance in weight. This work advances our understanding of mammalian growth by describing genetic contributions to canine size determination in non-giant dog breeds.


Assuntos
Tamanho Corporal/genética , Cruzamento , Cães/genética , Variação Genética , Alelos , Animais , Marcadores Genéticos , Genoma , Estudo de Associação Genômica Ampla , Genótipo , Glicoproteínas/genética , Proteína HMGA2/genética , Fator de Crescimento Insulin-Like I/genética , Dados de Sequência Molecular , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Receptor IGF Tipo 1/genética , Receptores da Somatotropina/genética , Proteína Smad2/genética
12.
PLoS One ; 7(7): e39929, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22808074

RESUMO

Horse body size varies greatly due to intense selection within each breed. American Miniatures are less than one meter tall at the withers while Shires and Percherons can exceed two meters. The genetic basis for this variation is not known. We hypothesize that the breed population structure of the horse should simplify efforts to identify genes controlling size. In support of this, here we show with genome-wide association scans (GWAS) that genetic variation at just four loci can explain the great majority of horse size variation. Unlike humans, which are naturally reproducing and possess many genetic variants with weak effects on size, we show that horses, like other domestic mammals, carry just a small number of size loci with alleles of large effect. Furthermore, three of our horse size loci contain the LCORL, HMGA2 and ZFAT genes that have previously been found to control human height. The LCORL/NCAPG locus is also implicated in cattle growth and HMGA2 is associated with dog size. Extreme size diversification is a hallmark of domestication. Our results in the horse, complemented by the prior work in cattle and dog, serve to pinpoint those very few genes that have played major roles in the rapid evolution of size during domestication.


Assuntos
Cruzamento , Loci Gênicos , Variação Genética , Genoma , Cavalos/genética , Animais , Tamanho Corporal , Bovinos , Proteínas de Ciclo Celular/genética , Cães , Feminino , Estudo de Associação Genômica Ampla , Proteína HMGA2/genética , Haplótipos , Humanos , Masculino , Fatores de Transcrição/genética , Dedos de Zinco
13.
J Nutr Biochem ; 23(11): 1440-8, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22305406

RESUMO

Activated skeletal muscle satellite cells facilitate muscle repair or growth through proliferation, differentiation and fusion into new or existing myotubes. Elevated levels of the proinflammatory cytokine tumor necrosis factor-α (TNF-α) impair this process and are documented to have significant roles in muscle pathology. Recent evidence shows that the ω-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) can block TNF-mediated suppression of progenitor cell differentiation, but the nature of this activity and its significance for local regulation of inflammation are not known. In the current study, we examined differentiation of the C2C12 myoblast line during treatment with TNF-α and EPA and measured the expression, activation and inhibition of peroxisome proliferator-activated receptor-γ (PPARγ), as several studies have shown its involvement in mediating EPA activity and the inhibition of nuclear factor (NF)-κB inflammatory gene activation. We found that TNF-α treatment increased NF-κB activity and reduced expression and activation of PPARγ, resulting in impaired myotube formation. EPA treatment attenuated these effects of TNF-α and was associated with up-regulation of PPARγ. Furthermore, EPA inhibited TNF-α-mediated transcription and secretion of interleukin (IL)-6, a key target gene of TNF-mediated NF-κB transcriptional activity. Pretreatment with a PPARγ selective antagonist inhibited some of the actions of EPA but was only partially effective in reversing inhibition of IL-6 production. These results show that EPA activity was associated with altered expression and activation of PPARγ, but exerted through both PPARγ-dependent and PPARγ-independent pathways leading to suppression of the proinflammatory cellular microenvironment.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Diferenciação Celular/efeitos dos fármacos , Ácido Eicosapentaenoico/farmacologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/patologia , PPAR gama/metabolismo , Fator de Necrose Tumoral alfa/farmacologia , Animais , Linhagem Celular , Regulação da Expressão Gênica/efeitos dos fármacos , Interleucina-6/genética , Interleucina-6/metabolismo , Camundongos , Músculo Esquelético/metabolismo , NF-kappa B/genética , NF-kappa B/metabolismo , PPAR gama/genética , Fator de Necrose Tumoral alfa/metabolismo
14.
PPAR Res ; 2012: 128068, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-21772837

RESUMO

Peroxisome proliferator-activated receptors (PPARs) have been demonstrated to have a role in immune regulation. In general, they are anti-inflammatory and promote Th2 type responses, and they are associated with the alternative activation of macrophages. Interestingly, helminth infections, such as the schistosome blood flukes that cause schistosomiasis, are characterised by a Th2 response and the accumulation of alternative activated macrophages. This would suggest that at some level, PPARs could have a role in the modulation of the immune response in schistosomiasis. This paper discusses possible areas where PPARs could have a role in this disease.

15.
Curr Top Behav Neurosci ; 9: 317-40, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-21728139

RESUMO

Epigenetics is the field of research that examines alterations in gene expression caused by mechanisms other than changes in DNA sequence. ADHD is highly heritable; however, epigenetics are considered relevant in potentially explaining the variance not accounted for by genetic influence. In this chapter, some of the well-known processes of epigenetics, such as chromosome organization, DNA methylation, and effects of transcriptional factors are reviewed along with studies examining the role of these processes in the pathophysiology of ADHD. Potential epigenetic factors conferring risk for ADHD at various developmental stages, such as alcohol, tobacco, toxins, medications, and psychosocial stressor are discussed. Animal studies investigating ADHD medications and changes in CNS Gene/Protein Expression are also explored since they provide insight into the neuronal pathways involved in ADHD pathophysiology. The current limited data suggest that identification of the epigenetic processes involved in ADHD is extremely important and may lead to potential interventions that may be applied to modify the expression of deleterious, as well as protective, genes.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Epigênese Genética , Epigenômica , Acontecimentos que Mudam a Vida , Transtorno do Deficit de Atenção com Hiperatividade/genética , Transtorno do Deficit de Atenção com Hiperatividade/metabolismo , Metilação de DNA/genética , Humanos
16.
Langmuir ; 27(5): 1821-9, 2011 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-21226497

RESUMO

An understanding of the structure of water on metal oxide nanoparticles is important due to its involvement in a number of surface processes, such as in the modification of transport near surfaces and the resulting impact on crystal growth and dissolution. However, as direct experimental measurements probing the metal oxide-water interface of nanoparticles are not easily performed, we use atomistic simulations using experimentally derived potential parameters to determine the structure and dynamics of the interface between magnesium oxide nanoparticles and water. We use a simple strategy to generate mineral nanoparticles, which can be applied to any shape, size, or composition. Molecular dynamics simulations were then used to examine the structure of water around the nanoparticles, and highly ordered layers of water were found at the interface. The structure of water is strongly influenced by the crystal structure and morphology of the mineral and the extent of hydroxylation of the surface. Comparison of the structure and dynamics of water around the nanoparticles with their two-dimensional flat surface counterparts revealed that the size, shape, and surface composition also affects properties such as water residence times and coordination number.

17.
Source Code Biol Med ; 5: 10, 2010 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-21159202

RESUMO

Research laboratories studying the genetics of companion animals have no database tools specifically designed to aid in the management of the many kinds of data that are generated, stored and analyzed. We have developed a relational database, "DOG-SPOT," to provide such a tool. Implemented in MS-Access, the database is easy to extend or customize to suit a lab's particular needs. With DOG-SPOT a lab can manage data relating to dogs, breeds, samples, biomaterials, phenotypes, owners, communications, amplicons, sequences, markers, genotypes and personnel. Such an integrated data structure helps ensure high quality data entry and makes it easy to track physical stocks of biomaterials and oligonucleotides.

18.
Parasit Vectors ; 3(1): 60, 2010 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-20663176

RESUMO

Fibrogenesis is a common feature of many diseases where there is severe insult to the liver. The hepatic stellate cell trans-differentiation into a myofibroblast has been identified as an important event in liver fibrogenesis and has been well investigated over the last few years in a number of liver diseases. The trans-differentiation process can be monitored in vitro by evaluation of biomarkers that are characteristic of normal quiescent hepatic stellate cells or activated myofibroblasts. Two major parasitic diseases associated with liver injury and fibrosis are schistosomiasis and echinococcosis. Recent studies have highlighted a role for activated hepatic stellate cells in both murine and human schistosomiasis as well as demonstrating that schistosome antigens are able to regulate this trans-differentiation process. Study of the hepatic stellate cell and its interaction with parasite-derived antigens may be pivotal in our understanding of the pathology associated with schistosomiasis and other parasitic diseases, including echinococcosis, as well as revealing new information on the trans-differentiation process in this cell type.

19.
Exp Parasitol ; 124(4): 409-20, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20045695

RESUMO

Eggs of Schistosoma mansoni trapped in human liver can lead to fibrosis. Since liver fibrosis requires activation of hepatic stellate cells (HSC) from a quiescent to a myofibroblastic phenotype, we investigated the effects of S. mansoni eggs on this process using in vitro co-cultures with human HSC and evaluated established biomarkers for activation and fibrosis. HSC demonstrate significantly reduced expression of alpha-smooth muscle actin (p<0.001), connective tissue growth factor (p<0.01) and type I collagen (p<0.001) but significantly increased expression of peroxisome proliferator-activated receptor-gamma (p<0.01). Morphologically, HSC exhibited elongated fine cellular processes and reduced size, increased accumulation of lipid droplets and reduced expression and organization of alpha-smooth muscle actin and F-actin stress fibres. Additionally, schistosome eggs prevented the HSC fibrogenic response to exogenous transforming growth factor-beta. In summary, schistosome eggs blocked fibrogenesis in HSC, a finding which may have implications for our understanding of the fibrotic pathology in S. mansoni infections.


Assuntos
Células Estreladas do Fígado/citologia , Cirrose Hepática/parasitologia , Fígado/patologia , Schistosoma mansoni/fisiologia , Esquistossomose mansoni/patologia , Animais , Linhagem Celular , Técnica Indireta de Fluorescência para Anticorpo , Células Estreladas do Fígado/efeitos dos fármacos , Células Estreladas do Fígado/parasitologia , Interações Hospedeiro-Parasita , Humanos , Fígado/citologia , Fígado/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia de Contraste de Fase , PPAR gama/biossíntese , Fenótipo , Reação em Cadeia da Polimerase , Fator de Crescimento Transformador beta/farmacologia
20.
Proc Natl Acad Sci U S A ; 106(31): 13088-93, 2009 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-19622729

RESUMO

We have shown that somatostatin released from activated capsaicin-sensitive nociceptive nerve endings during inflammatory processes elicits systemic anti-inflammatory and analgesic effects. With the help of somatostatin receptor subtype 4 gene-deleted mice (sst(4)(-/-)), we provide here several lines of evidence that this receptor has a protective role in a variety of inflammatory disease models; several symptoms are more severe in the sst(4) knockout animals than in their wild-type counterparts. Acute carrageenan-induced paw edema and mechanical hyperalgesia, inflammatory pain in the early phase of adjuvant-evoked chronic arthritis, and oxazolone-induced delayed-type hypersensitivity reaction in the skin are much greater in mice lacking the sst(4) receptor. Airway inflammation and consequent bronchial hyperreactivity elicited by intranasal lipopolysaccharide administration are also markedly enhanced in sst(4) knockouts, including increased perivascular/peribronchial edema, neutrophil/macrophage infiltration, mucus-producing goblet cell hyperplasia, myeloperoxidase activity, and IL-1beta, TNF-alpha, and IFN-gamma expression in the inflamed lung. It is concluded that during these inflammatory conditions the released somatostatin has pronounced counterregulatory effects through sst(4) receptor activation. Thus, this receptor is a promising novel target for developing anti-inflammatory, analgesic, and anti-asthmatic drugs.


Assuntos
Hiper-Reatividade Brônquica/etiologia , Hiperalgesia/etiologia , Inflamação/etiologia , Receptores de Somatostatina/fisiologia , Animais , Hiper-Reatividade Brônquica/prevenção & controle , Dermatite Alérgica de Contato/etiologia , Feminino , Hiperalgesia/prevenção & controle , Inflamação/prevenção & controle , Lipopolissacarídeos/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Oxazolona/toxicidade , Receptores de Somatostatina/deficiência , Receptores de Somatostatina/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA