RESUMO
OBJECTIVES: The purpose of the present study was to determine if protecting parenteral nutrition solutions from ambient light and supplementing with N-acetylcysteine (NAC) improves mesenteric blood flow, gut morphology, and oxidative status of parenterally fed neonates. METHODS: Neonatal Yucatan miniature piglets (nâ=â23, 7-11 days old) were surgically fitted with central venous catheters and an ultrasonic blood flow probe around the superior mesenteric artery. Piglets were fed continuously for 7 days either light-protected (LP) or light-exposed (LE) complete parenteral nutrition that was enriched with either NAC or alanine (ALA). RESULTS: There were no differences in body weight or overall gut morphology among groups after 7 days. Plasma concentrations of NAC were greater and total homocysteine lower in NAC- versus ALA-supplemented pigs on day 7 (N-acetylcysteine: 94 vs 7âµmol/L; Pâ<â0.001; homocysteine: 14 versus 21âµmol/L; Pâ<â0.005); plasma total glutathione was not affected. Hepatic lipid peroxidation was reduced by 25% in piglets that received LP parenteral nutrition (Pâ<â0.05). The mesenteric artery blood flow decreased in all pigs between days 2 and 6 (Pâ<â0.001) because of parenteral feeding. Photoprotection alone (LP-ALA) attenuated the decrease in mesenteric blood flow to 66% of baseline on day 6 compared with LE-ALA (37%; Pâ<â0.05) and LP-NAC pigs (43%; Pâ=â0.062); LE-NAC piglets had intermediate reductions in blood flow (55%). CONCLUSIONS: Photoprotection of parenteral nutrition solutions is a simple, effective method to attenuate decline in blood flow to the gut and hepatic lipid peroxidation, which are both commonly associated with parenteral feeding.
Assuntos
Acetilcisteína/administração & dosagem , Luz/efeitos adversos , Nutrição Parenteral Total/métodos , Animais , Animais Recém-Nascidos , Modelos Animais de Doenças , Feminino , Humanos , Intestinos/irrigação sanguínea , Masculino , Artérias Mesentéricas/fisiologia , Oxirredução , Distribuição Aleatória , SuínosRESUMO
It is challenging to quantify the geometrically necessary dislocation (GND) density at the nanoscale using conventional electron backscatter diffraction due to its limited spatial resolution. To overcome this problem, in this study, the transmission Kikuchi diffraction (TKD) technique is used to measure lattice orientation and to calculate the corresponding nanoscale GND density. Using the TKD method, a variation of GND density from 6â¯×â¯1014 to 1016 m-2 has been measured in a welded super duplex stainless steel sample. The distribution of dislocation density is shown to be in good agreement with transmission electron microscope (TEM) result. Compared with dislocation measurements obtained by TEM, the TKD-GND method is revealed to be a relatively accurate, fast and accessible method.
RESUMO
UNLABELLED: PepT1, a di/tripeptide transporter, is preferentially preserved over free amino acid transporters in situations of gut stress. Therefore, our objective was to determine the impact of enterally delivered dipeptide-containing diets on indices of intestinal adaptation in neonatal piglets after intestinal resection. METHODS: Piglets (n = 25, 10 ± 1 d old) underwent an 80% jejuno-ileal resection and were provided 50% of nutritional support as TPN, and 50% as one of five, enteral test diets: 1) a control diet containing free amino acids, or the same diet but with equimolar amounts of free amino acids replaced by 2) alanyl-alanine, 3) alanyl-glutamine, 4) cysteinyl-glycine, or 5) both alanyl-alanine and cysteinyl-glycine. After 4 d of enteral feeding, indices of intestinal adaptation were assessed. Outcome measures included plasma and mucosal amino acid concentrations, morphological and histological parameters, protein synthesis, PepT1 mRNA and protein expression, and mucosal cytokine concentrations. RESULTS: Intestinal length, organ weight and protein synthesis rates were not different amongst groups. All of the dipeptide-containing diets reduced pro-inflammatory cytokine concentrations in the mucosa (TNF-α, IFN-γ). The cysteinyl-glycine diet supported greater villus height compared to all other dipeptides and greater crypt depth compared to alanyl-glutamine; however, none of the dipeptide diets altered intestinal morphology compared to the free amino acid control diet. CONCLUSIONS: This study showed that while there was no explicit morphological benefit of enteral dipeptides over their constituent free amino acids, there was the potential for the amelioration of intestinal inflammation by reducing pro-inflammatory cytokines. Enteral provision of dipeptides impacted intestinal adaptation, but the response was dipeptide-specific.
Assuntos
Dipeptídeos/administração & dosagem , Nutrição Enteral , Inflamação/metabolismo , Intestino Delgado/efeitos dos fármacos , Animais , Modelos Animais de Doenças , Glutationa/metabolismo , Interferon gama/metabolismo , Intestino Delgado/metabolismo , Intestino Delgado/cirurgia , Tamanho do Órgão , Suínos , Resultado do Tratamento , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Rhabdovirus infections are an emerging problem for both wild and farmed freshwater fish in Northern Europe. In October 2005, a clinical outbreak with an approximate mortality rate of 40% occurred in a single batch of juvenile perch on a farm in the Republic of Ireland. Clinical signs developed slowly and were consistent with a perch rhabdovirus infection: signs included haemorrhages at the base of the fins and apparent impairment of the central nervous system (manifested as loss of equilibrium and erratic swimming behaviour). Studies suggest that the infected fish originated from a hatchery within the country which relied on wild fish broodstock to supplement the production of perch juveniles. A related rhabdovirus was subsequently isolated from this hatchery. Virus isolation studies have shown that rhabdoviruses were often isolated from wild fish in the vicinity of the hatchery between 1993 and 2005. All isolates were analysed using a generic primer set specific for the L gene of fish vesiculotype viruses. Phylogenetic analysis revealed that all isolates recovered from perch clustered together with the European lake trout rhabdovirus (903/87) of the genus Perhabdovirus. In addition to this, anguillid rhabdovirus was isolated from eel, and the partial L-gene sequence of a previously reported isolate from tench clustered with the pike fry rhabdoviruses, in the genus Sprivivirus.
Assuntos
Doenças dos Peixes/virologia , Variação Genética , Percas , Infecções por Rhabdoviridae/veterinária , Rhabdoviridae , Animais , Aquicultura , Sequência de Bases , Doenças dos Peixes/epidemiologia , Irlanda/epidemiologia , Filogenia , RNA Viral/genética , Infecções por Rhabdoviridae/virologiaRESUMO
BACKGROUND: Arginine is an indispensable amino acid in neonates; de novo synthesis of arginine occurs in the small intestine (SI) but is reduced during parenteral nutrition (PN), limiting the arginine available to the mucosa. We assessed the effects of route of intake and dietary concentration of arginine on protein synthesis, superior mesenteric artery (SMA) blood flow, and SI morphology. METHODS: Piglets (n = 18, 14-17 days old) were given complete PN for 3 days to induce SI atrophy, then switched to 1 of 3 treatments: arginine-free PN plus an intragastric (IG) infusion of high arginine (1.6 g · kg(-1)· d(-1), IG-H Arg) or low arginine (0.6 g · kg(-1)· d(-1), IG-L Arg) or complete high-arginine PN (1.6 g · kg(-1)· d(-1), IV-H Arg). RESULTS: Enteral arginine, irrespective of amount provided, stimulated hepatic protein synthesis compared with intravenous delivery of arginine (P = .01). SMA blood flow declined for all groups following the initiation of PN. After 48 hours on the test diets, all groups reached low constant levels, but the IV-H group was significantly higher than both IG groups (P < .05). Despite greater blood flow, the SI morphological characteristics in IV-H Arg pigs were not significantly improved over the other groups. IV-H Arg pigs had higher plasma concentrations of indispensable amino acids (tyrosine, isoleucine, and valine) compared with IG-H Arg, despite identical amino acid intakes. CONCLUSIONS: Intravenous delivery of arginine sustained the best SMA blood flow, whereas even a moderate amount of enteral arginine stimulated liver protein synthesis and maintained SI growth, independent of blood flow.
Assuntos
Arginina/farmacologia , Nutrição Enteral , Intestino Delgado/efeitos dos fármacos , Fígado/efeitos dos fármacos , Nutrição Parenteral Total/efeitos adversos , Biossíntese de Proteínas/efeitos dos fármacos , Aminoácidos Essenciais/sangue , Animais , Animais Recém-Nascidos , Arginina/administração & dosagem , Arginina/metabolismo , Atrofia/etiologia , Dieta , Mucosa Intestinal , Intestino Delgado/irrigação sanguínea , Intestino Delgado/crescimento & desenvolvimento , Intestino Delgado/patologia , Fígado/metabolismo , Masculino , Artéria Mesentérica Superior , Tamanho do Órgão , Nutrição Parenteral , Fluxo Sanguíneo Regional , SuínosRESUMO
Viral haemorrhagic septicaemia (VHS), caused by the novirhabdovirus VHSV, often leads to significant economic losses to European rainbow trout production. The virus isolates are divided into 4 distinct genotypes with additional subgroups including sublineage Ia, isolates of which are the main source of outbreaks in European rainbow trout farming. A significant portion of Danish rainbow trout farms have been considered endemically infected with VHSV since the first disease outbreak was observed in the 1950s. However, following a series of sanitary programs starting in 1965, VHSV has not been detected in Denmark since January 2009. Full-length G-genes of all Danish VHSV isolates that were submitted for diagnostic analyses in the period 2004-2009 were sequenced and analysed. All 58 Danish isolates from rainbow trout grouped with sublineage Ia isolates. Furthermore, VHSV isolates from infected Danish freshwater catchments appear to have evolved into a distinct clade within sublineage Ia, herein designated clade Ia-1, whereas trout isolates originating from other continental European countries cluster in another distinct clade, designated clade Ia-2. In addition, phylogenetic analyses indicate that VHSV Ia-1 strains have caused a few outbreaks in Germany and the UK. It is likely that viruses have been transmitted from infected site(s) out of the Danish environment, although a direct transmission pathway has not been identified. Furthermore, VHSV Ia-2 isolates seem to have been transmitted to Denmark at least once. Interestingly, one viral isolate possibly persisted in a Danish watershed for nearly 4 yr without detection whereas other subclades of VHSV isolates appear to have been eliminated, probably because of implemented eradication procedures.
Assuntos
Genótipo , Septicemia Hemorrágica Viral/virologia , Novirhabdovirus/classificação , Novirhabdovirus/genética , Oncorhynchus mykiss , Animais , Dinamarca/epidemiologia , Septicemia Hemorrágica Viral/epidemiologia , Filogenia , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Fatores de TempoRESUMO
BACKGROUND: Successful small intestinal (SI) adaptation following surgical resection is essential for optimizing newborn growth and development, but the potential for adaptation is unknown. The authors developed an SI resection model in neonatal piglets supported by intravenous and enteral nutrition. METHODS: Piglets (n = 33, 12-13 days old) were randomized to 80% SI resection with parenteral nutrition feeding (R-PN), 80% SI resection with PN + enteral feeding (R-EN), or sham SI transection with PN + enteral feeding (sham-EN). In resected pigs, the distal 100 cm of ileum (residual SI) and 30 cm of proximal SI were left intact. All pigs received parenteral nutrition postsurgery. Enteral nutrition piglets received continuous gastric infusion of elemental diet from day 3 (40:60 parenteral nutrition:enteral nutrition). Piglets were killed 4, 6, or 10 days postsurgery. RESULTS: By 10 days, R-EN piglets had longer residual SI than R-PN and sham-EN pigs (P < .05). At days 6 and 10, R-EN piglets had greater weight per length of intact SI (P < .05) and isolated mucosa (P < .05) compared to other groups. Greater gut weight in R-EN piglets was facilitated by a greater cellular proliferation index (P < .01) by 4 days compared to other groups and greater overall ornithine decarboxylase activity vs R-PN piglets (P < .05). CONCLUSIONS: This new model demonstrated profound SI adaptation, initiated early postsurgery by polyamine synthesis and crypt cell proliferation and only in response to enteral feeding. These changes translated to greater gut mass and length within days, likely improving functional capacity long term.
Assuntos
Adaptação Fisiológica , Nutrição Enteral , Mucosa Intestinal/crescimento & desenvolvimento , Intestino Delgado/crescimento & desenvolvimento , Nutrição Parenteral , Síndrome do Intestino Curto/terapia , Animais , Animais Recém-Nascidos , Proliferação de Células , Modelos Animais de Doenças , Íleo , Mucosa Intestinal/citologia , Intestino Delgado/citologia , Intestino Delgado/cirurgia , Tamanho do Órgão , Ornitina Descarboxilase/metabolismo , Distribuição Aleatória , Síndrome do Intestino Curto/metabolismo , Síndrome do Intestino Curto/cirurgia , SuínosRESUMO
This study investigated the use of alkaline hydrolysis at ambient temperature for inactivation of selected fish pathogens in fish tissues under conditions approximating those that are likely to be found in the aquaculture industry. Infectious salmon anaemia virus (ISAV) and Lactococcus garvieae have been determined in a previous study to be the most resistant virus and bacteria to pH 12 from a wide range of viruses and bacteria tested. They were spiked at high titres into fish extracts that were then treated with 1 m sodium hydroxide (NaOH). Viable L. garvieae was not detected in the treated fish extract after 1 h, and ISAV was not detected after 24-h exposure. Field mortalities of Atlantic salmon, Salmo salar L., caused by infectious pancreatic necrosis virus were treated by alkaline hydrolysis at ambient temperature. The macerated fish mortalities contained a high titre of virus (3.38 × 108 TCID50 g⻹) that was reduced to approximately 2.2 × 10³ TCID50 g⻹ after 24-h exposure to NaOH, and virus was not detected after exposure for 48 h. The results suggest that alkaline hydrolysis at ambient temperature has potential as a biosecure treatment method for fish by-products containing fish pathogens.
Assuntos
Aquicultura/métodos , Doenças dos Peixes/microbiologia , Doenças dos Peixes/virologia , Eliminação de Resíduos de Serviços de Saúde/métodos , Viabilidade Microbiana , Inativação de Vírus , Animais , Infecções por Birnaviridae/veterinária , Infecções por Birnaviridae/virologia , Peixes , Concentração de Íons de Hidrogênio , Vírus da Necrose Pancreática Infecciosa/fisiologia , Eliminação de Resíduos de Serviços de Saúde/normas , Salmonidae/virologiaRESUMO
Disposal of fish by-products in the European Community must comply with Regulation (EC) No 1069/2009 which categorizes animal by-products according to risk, and specifies methods of disposal of by-products according to that risk. There is provision under the regulation for composting or ensiling to be used for by-products from aquatic animals. Biosecurity considerations require knowledge of the parameters of time and temperature, or time and pH, required to inactivate any fish pathogens that may be present. To provide those data, we undertook laboratory studies on the inactivation of a number of fish pathogenic viruses and bacteria at 60 °C, pH 4.0 and pH 12.0 as a preliminary to conducting subsequent trials with the most resistant viruses and bacteria in fish tissues. The most resistant bacterium to 60 °C, pH 4.0 as well as pH 12.0 was Lactococcus garvieae. Its concentration was reduced to the level of sensitivity of the test after 24-48 h exposure to 60 °C, but it survived for at least 7 days at pH 4.0 and 14 days at pH 12.0. The most resistant virus to 60 °C was infectious pancreatic necrosis virus, and to pH 12.0 was infectious salmon anaemia virus. The majority of the viruses tested survived exposure to pH 4.0 for up to 28 days. The results suggest that the process of acid ensiling alone is not an effective method for the inactivation of many viral and bacterial pathogens, and fish by-products would need further treatment by a method approved under the regulation following ensiling, whereas alkaline or heat treatment are likely to provide an increased degree of biosecurity for on-farm processing of mortalities.
Assuntos
Fenômenos Fisiológicos Bacterianos , Doenças dos Peixes/microbiologia , Doenças dos Peixes/virologia , Viabilidade Microbiana , Temperatura , Inativação de Vírus , Fenômenos Fisiológicos Virais , Animais , Peixes , Concentração de Íons de Hidrogênio , Reprodutibilidade dos TestesRESUMO
Market-sized rainbow trout Oncorhynchus mykiss were challenged by waterborne exposure to viral haemorrhagic septicaemia virus (VHSV isolate of genogroup Ia). Fish were sampled at 4 stages of infection (before onset of clinical signs, clinically affected fish, mortalities and survivors) and the viral load determined in (1) internal organs, (2) muscle tissue and (3) brain and gill tissue. Virus levels were determined by virus titration and real-time RT-PCR. VHSV was detected by either method in the majority of fish before onset of clinical signs and in the survivor group as well as in all fish in the clinically affected fish and mortality groups. Mean virus amounts per mg of tissue determined by virus titration (TCID50) or real-time RT-PCR (copy number) were > 10(4) in preclinical fish, > 10(3.8) in clinically affected fish, > 10(3.9) in mortalities and > 10(1.2) in survivors. Virus levels tended to be highest in the internal organs of subclinical and clinically affected fish and in brain and gill tissue of survivors. The results demonstrate that significant levels of VHSV can be found in tissues of rainbow trout that may be marketed for human consumption, which may have relevance for the biosecurity of VHS-free areas.
Assuntos
Septicemia Hemorrágica Viral/virologia , Novirhabdovirus/fisiologia , Oncorhynchus mykiss , Carga Viral , Animais , RNA Viral/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterináriaRESUMO
Movements of commodity fish present a potential risk of transferring pathogens. Within a study to estimate the risk from imported rainbow trout Oncorhynchus mykiss carcases, fry were exposed to tissue homogenates from market size rainbow trout infected experimentally with viral haemorrhagic septicaemia (VHS) by waterborne exposure to VHS virus (VHSV, isolate of genotype Ia). Tissues were collected from fish that showed clinical signs and from recent mortalities. Homogenates of (i) internal organs, (ii) brain/gills and (iii) muscle tissue were prepared and added to tanks holding the fry. Virus transmission occurred from all tissues tested, causing high mortality of the fry. The results underline the potential risk of introduction of VHSV through the trade of fish products.
Assuntos
Novirhabdovirus/isolamento & purificação , Oncorhynchus mykiss/virologia , Infecções por Rhabdoviridae/transmissão , Animais , Comércio , Primers do DNA , Modelos Animais de Doenças , Novirhabdovirus/genética , Infecções por Rhabdoviridae/mortalidade , Medição de Risco , Microbiologia da ÁguaRESUMO
Viral haemorrhagic septicaemia (VHS) was diagnosed in rainbow trout in the UK in May 2006. VHS virus (VHSV) was isolated from fingerlings showing typical histopathological lesions at a single rainbow trout farm site experiencing high mortality. The virus was confirmed as VHSV by serological and molecular biological tests. Phylogenetic analysis based on the complete glycoprotein gene sequence revealed that the isolate was closely related (99% nucleotide identity) to several Danish isolates from 1991 to 2000 and was assigned to VHSV genogroup Ia. The pathogenicity of the isolate was determined in infection experiments using rainbow trout fry. Following waterborne challenge, cumulative mortalities reached 96.67-100% by 12 days post-infection. This represents the first isolation of a pathogenic freshwater VHSV in the UK.
Assuntos
Septicemia Hemorrágica Viral/epidemiologia , Septicemia Hemorrágica Viral/virologia , Novirhabdovirus/isolamento & purificação , Oncorhynchus mykiss/virologia , Animais , Ensaio de Imunoadsorção Enzimática , Septicemia Hemorrágica Viral/patologia , Septicemia Hemorrágica Viral/transmissão , Novirhabdovirus/classificação , Novirhabdovirus/genética , Novirhabdovirus/patogenicidade , Filogenia , Reino Unido/epidemiologiaRESUMO
Heat shock protein 27 (Hsp27), a molecular chaperone ubiquitously expressed in many cell types, has been shown to play a role in protecting neurons from cellular stresses. Unlike adult DRG neurons in vitro, neonatal DRG neurons require NGF for survival; withdrawal of NGF results in apoptosis of a majority of neonatal neurons. We hypothesized that Hsp27 contributes to the neurotrophin-independent survival of adult DRG neurons. Constitutive Hsp27 expression is higher in adult DRG neurons compared to neonates, although both upregulate Hsp27 expression after heat shock (HS). We found that increasing endogenous Hsp27 by HS in neonatal neurons was able to inhibit NGF withdrawal-induced apoptosis. Heat shock of adult and neonatal neurons also resulted in Akt activation, which could be a mechanism for the increased survival. Hsp27 siRNA treatment of adult neurons effected a decreased expression of Hsp27, which correlated with increased apoptosis in these neurons. Downregulation of Hsp27 via siRNA also blocked the HS-induced rescue of neonatal neurons after NGF withdrawal. These results indicate that physiologically induced upregulation of Hsp27 is sufficient to provide some degree of neuronal protection. Further, this induction appears to be regulated by the transcriptional activation of HSF1 as shown by HSF1 nuclear translocation and by EMSA analyses of HSF1 binding to nuclear protein.
Assuntos
Gânglios Espinais/citologia , Gânglios Espinais/fisiologia , Proteínas de Choque Térmico/biossíntese , Proteínas de Choque Térmico/fisiologia , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/fisiologia , Neurônios/fisiologia , Animais , Animais Recém-Nascidos/fisiologia , Western Blotting , Sobrevivência Celular/fisiologia , Células Cultivadas , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Ensaio de Desvio de Mobilidade Eletroforética , Proteínas de Choque Térmico HSP27 , Fatores de Transcrição de Choque Térmico , Temperatura Alta , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Fármacos Neuroprotetores , Fosforilação , RNA Interferente Pequeno/farmacologia , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estresse Fisiológico/patologia , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Regulação para Cima/fisiologiaRESUMO
Electro-optic measurements were performed on a lamellar nematic phase in which the mesogenic moieties lie in lamellae that are separated by partially perfluorinated side groups. The twist elastic constant K22, viscosity gamma(1), and the quadratic and quartic anchoring strength coefficients are reported. K22 and gamma(1) are found to be considerably smaller than that of typical three-dimensional nematics. The small K22 is due to the greatly weakened interactions between the spatially separated lamellae.
RESUMO
We have investigated the role of stress-activated signaling pathways and the small heat shock protein, Hsp27, in protecting PC12 cells from heat shock and nerve growth factor (NGF) withdrawal-induced apoptosis. PC12 cells and a stable cell line overexpressing Hsp27 (HSPC cells) were subjected to heat shock. This resulted in the rapid activation of Akt followed by p38 mitogen-activated protein kinase (MAPK) signaling, with phosphorylation and intracellular translocation of Hsp27 also detectable. Hsp27 was found to form an immunoprecipitable complex with Akt and p38 MAPK in both non-stimulated and heat shocked cells, although after heat shock there was a gradual dissociation of Akt and p38 from the Hsp27. Cells were differentiated with NGF and then subjected to NGF withdrawal, a treatment which results in substantial cell death over 24-72 h. Hsp27 was shown to be protective against this treatment, since HSPC cells which overexpress Hsp27 showed significantly less cell death than the parental PC12 cells. In addition, we observed that phosphorylation of Akt was maintained in HSPC cells subjected to heat shock and NGF withdrawal compared with the parental cells. Taken together, our results suggest that Hsp27 may protect Akt from dephosphorylation and may also act in stabilizing Akt.
Assuntos
Proteínas de Choque Térmico , Proteínas de Neoplasias/fisiologia , Fator de Crescimento Neural/farmacologia , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas/fisiologia , Transdução de Sinais/fisiologia , Estresse Fisiológico/metabolismo , Transporte Ativo do Núcleo Celular/fisiologia , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Ativação Enzimática/fisiologia , Proteínas de Choque Térmico HSP27 , Resposta ao Choque Térmico/fisiologia , Temperatura Alta , Imuno-Histoquímica , Proteínas Luminescentes/genética , Substâncias Macromoleculares , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fator de Crescimento Neural/deficiência , Fármacos Neuroprotetores/metabolismo , Fármacos Neuroprotetores/farmacologia , Células PC12 , Fosforilação , Testes de Precipitina , Proteínas Proto-Oncogênicas c-akt , Ratos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por MitógenoRESUMO
Dorsal root ganglion (DRG) sensory neurons become less dependent upon neurotrophins for their survival as they mature. DRG neurons from young adult rats were dissociated and cultured in vitro in serum-free defined medium. We show that adult DRG sensory neurons are able to survive for at least 2 weeks in culture in the absence of nerve growth factor (NGF). We then investigated potential mechanisms contributing to this apparent neurotrophin-independent survival in these neurons through the use of inhibitors of cellular signaling pathways. The phosphoinositide kinase-3 (PI 3-K) inhibitor LY294002, and a protein kinase C (PKC) inhibitor, chelerythrine resulted in significant decreases in neuronal survival. Neither the mitogen activated protein kinase kinase (MEK) inhibitor U0126 nor two other PKC inhibitors (bisindolylmaleimide and rottlerin) had any significant effect on survival. Our results point to the importance of PI 3-K and PKC signaling in the neurotrophin-independent survival of adult DRG neurons.
Assuntos
Gânglios Espinais/citologia , Fator de Crescimento Neural/farmacologia , Neurônios Aferentes/citologia , Neurônios Aferentes/fisiologia , Fatores Etários , Alcaloides , Animais , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Benzofenantridinas , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Células Cultivadas , Cromonas/farmacologia , Inibidores Enzimáticos/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Morfolinas/farmacologia , Fenantridinas/farmacologia , Inibidores de Fosfoinositídeo-3 Quinase , Proteína Quinase C/antagonistas & inibidores , Ratos , Ratos Sprague-DawleyRESUMO
BACKGROUND: While some cognitive accounts of disorganized speech, or thought disorder, in schizophrenia have emphasized failures in working memory/discourse planning or selective attention, we have suggested that thought disorder resides in the semantic system. In this study we assessed the effect of neuroleptic medication on thought disorder and semantic processing. METHODS: Seventeen patients with schizophrenia were assessed while receiving neuroleptic medications and in crossover fashion, placebo. A number of measures were obtained: clinically rated thought disorder (using the Thought, Language and Communication Scale); working memory letter number span); lexical integrity (naming and receptive vocabulary); and, semantic priming of intracategorical word pairs. RESULTS: Semantic priming measures improved with neuroleptic medication, as did clinically rated thought disorder. No other measure changed significantly. Priming selectively covaried with changes in thought disorder. CONCLUSION: Changes in spreading semantic activation, measured in a semantic priming paradigm and presumably brought about by neuroleptics' influence on dopaminergic neuromodulatory systems, might reflect changes in the biases of pre-existing associative networks that favour or increase the accessibility of representations related by shared features. This study also has implications for the architecture of normal language in that a dissociation between the lexical and semantic levels was observed, due to the selective compromise of tasks demanding semantic processing.
Assuntos
Antipsicóticos/uso terapêutico , Aprendizagem por Associação de Pares/efeitos dos fármacos , Esquizofrenia Hebefrênica/tratamento farmacológico , Esquizofrenia Paranoide/tratamento farmacológico , Linguagem do Esquizofrênico , Semântica , Pensamento/efeitos dos fármacos , Comportamento Verbal/efeitos dos fármacos , Adulto , Antipsicóticos/efeitos adversos , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esquizofrenia Hebefrênica/diagnóstico , Esquizofrenia Hebefrênica/psicologia , Esquizofrenia Paranoide/diagnóstico , Esquizofrenia Paranoide/psicologia , Resultado do TratamentoRESUMO
Since little is known about the effect of selenium on the fatty acid profiles (FAP) of human breast milk, the purpose of this study was to measure the effect of habitual dietary selenium (Se) intake on this profile in plasma and breast milk. Subjects were lactating women from three locations in China where habitual selenium intakes are extremely low (Xichang), adequate (Beijing), or extremely high (Enshi). Plasma and milk samples were obtained within seven days of parturition (early samples) or within eighteen months postpartum (mature samples) and analyzed for selenium concentration, glutathione peroxidase (Gpx) activity and FAP. Plasma and milk selenium concentrations were significantly lower in the samples from women from Xichang and significantly higher in those from Enshi when compared to those from Beijing. Plasma Gpx activity, however, was higher in samples from Beijing than Xichang or Enshi. In contrast, the early breast milk samples had similar Gpx activity regardless of location. The mature samples, however, followed the same trend as plasma with the samples obtained from the women in Beijing having the highest activity. Of the unsaturated fatty acids examined, the concentration of linoleic acid, 18:2(n-6), in both plasma and milk was greater in the samples from Beijing when compared to those from Xichang or Enshi. Thus dietary selenium appears to influence the fatty acid composition in human breast milk, but influences Gpx activity only in mature milk samples.
Assuntos
Ácidos Graxos/análise , Ácidos Graxos/sangue , Glutationa Peroxidase/metabolismo , Leite Humano/metabolismo , Adulto , China , Relação Dose-Resposta a Droga , Feminino , Humanos , Ácido Linoleico/análise , Ácido Linoleico/sangue , Selênio/análise , Selênio/sangueRESUMO
We have examined the effect of a downstream secondary structure (the stem-loop sequence found downstream on the MMTV gag-pro frameshift site) on frameshifting at a bacterial shifty site (U UUC AUA) that responds strongly to a isoleucine-tRNA limitation. Our findings are as follows: (i) the downstream stem-loop has little effect on frameshifting in growing, unstarved cells; (ii) the stem-loop increases the frameshifting effect of isoleucine-tRNA limitation about fourfold, and this synergism is maximal with a distance of 5-9 nucleotides between the 'hungry' AUA codon and the stem-loop; and (iii) a stem-loop of different sequence at the same position has the same effect.