Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 152
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
J Dairy Sci ; 102(11): 10423-10438, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31477290

RESUMO

With increasing intensification of the dairy sector in many countries and with the introduction of automatic milking, exercise paddocks combined with full indoor feeding, as an alternative to production pasture, are being used as a compromise between farm economics and cow welfare. This study examined whether there are production benefits for high-producing dairy cows in an alternative system that uses pasture at a level of approximately 50% of the total roughage intake in the diet. In an automatic milking system with 12-h night access to the outdoor environment, we compared milk production and behavior of cows in 2 systems: an exercise paddock combined with ad libitum grass silage indoor feeding and a production pasture combined with a restricted daytime grass silage ration. There were 20 cows in the former and 21 cows in the latter system, with the treatments running in parallel. The experiment started in late June with no complete darkness during the night, and lasted for 12 wk, with 5.6 h of darkness at the end. We therefore also explored the effect of night length on milk production and behavior parameters. All cows showed strong motivation for going outdoors and grazing when pasture access was given in early evening, but after a few hours both groups went to the barn and did not return to the pasture area during the remaining night. As the season progressed and nights became longer, cows on the exercise paddock treatment reduced time spent outdoors and grazing time, whereas they increased time spent resting outdoors. The group on exercise paddock had a greater milk yield (kg of milk) over the experimental period than the production pasture group. The latter group also showed a greater drop in milk yield over the duration of the trial. Thus, for cows milked in an automatic milking system and offered nighttime outdoor access, no milk production benefits were observed in offering production pasture with restricted indoor silage allowance instead of an exercise paddock with ad libitum silage. We therefore suggest that automatic milking farmers with similar production levels and automatic milking-management systems as in the present experiment, who wish to include grazed grass as part of the dairy cow diet, should ensure that cows have pasture access in the afternoon and evening.


Assuntos
Comportamento Animal , Bovinos/fisiologia , Indústria de Laticínios/métodos , Dieta/veterinária , Lactação/fisiologia , Ração Animal/análise , Animais , Indústria de Laticínios/instrumentação , Fazendas , Feminino , Leite , Condicionamento Físico Animal , Poaceae , Silagem
2.
J Dairy Sci ; 100(10): 7990-8003, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28780102

RESUMO

Grass silage-based diets often result in poor nitrogen utilization when fed to dairy cows. Perennial ryegrass cultivars with high concentrations of water-soluble carbohydrates (WSC) have proven potential for correcting this imbalance when fed fresh, and have also been shown to increase feed intake, milk production, and N utilization. The possibility of achieving corresponding effects with silage-based diets was investigated in change-over experiments in an incomplete block design with 16 (yr 1) or 12 (yr 2) Swedish Red dairy cows in mid lactation. Measurements on N excretion and rumen parameters were performed on subgroups of 8 and 4 cows, respectively. In yr 1, 2 ryegrass cultivars (standard = Fennema; high-WSC = Aberdart) and 2 cuts (first and second) were compared. In all treatments, ryegrass silage was mixed 75/25 on a dry matter (DM) basis, with red clover silage before feeding out. In yr 2, 1 basic mixture from the different cuts of these 2 cultivars was used and experimental factors were red clover silage inclusion (25 or 50%) and sucrose addition (0 or 10%) on a silage DM basis. Differences in WSC concentration in the silage mixtures in yr 1 were minor, whereas the differences between cuts were more substantial: 100 compared with 111 g/kg of DM for first-cut silage and 39 compared with 47 g/kg of DM for second-cut silage. The silages fed in yr 2 had a WSC concentration of 115 or 102 g/kg of DM (25 or 50% red clover, respectively), but when sucrose was added WSC concentration reached 198 and 189 g/kg of DM, respectively. Milk production (kg/d) did not differ between treatments in either year. Red clover inclusion to 50% of silage DM increased milk protein. Nitrogen efficiency (milk N/feed N) increased from 0.231 to 0.254 with sucrose inclusion in yr 2 (average for the 2 red clover levels). Overall rumen pH was 5.99 and increased sucrose level did not affect pH level or daily pH pattern. Sucrose addition reduced neutral detergent fiber digestibility, particularly at higher inclusion rates of clover. Rumen pool of total purines did not differ between treatments, nor did protein production assessed from urinary allantoin. The NorFor feed evaluation model overestimated digestibility of neutral detergent fiber and N, but underestimated N excretion in feces. We concluded that addition of WSC to dairy cow diets at levels up to 3 kg of WSC per day (>14% of DM) does not dramatically affect cow performance.


Assuntos
Dieta/veterinária , Açúcares da Dieta/metabolismo , Ingestão de Alimentos , Lolium/química , Leite/metabolismo , Nitrogênio/metabolismo , Silagem , Trifolium/química , Animais , Bovinos , Dieta/métodos , Fibras na Dieta/administração & dosagem , Fibras na Dieta/metabolismo , Açúcares da Dieta/administração & dosagem , Digestão , Feminino , Lactação , Lolium/metabolismo , Rúmen/metabolismo , Suécia , Trifolium/metabolismo
3.
Opt Express ; 22(26): 32457-69, 2014 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-25607208

RESUMO

We investigate high dimensional modulation formats for multi-core fibers (MCFs) and spatial superchannels. We show that the low skew variations between MCF cores maybe exploited to generate 'multi-core' formats that offer significant advantages over independently transmitting conventional 4-dimensional formats in each core. We describe how pulse position modulation formats may be transposed to the spatial domain and then investigate a family of modulation formats referred to as core-coding, one of which has the same power and spectral efficiency as polarization switched quaternary phase shift keying but with half of the optical power, potentially improving non-linear tolerance for long distance transmission, albeit at the cost of implementation challenges. Finally, we investigate the application of set-partitioning to multi-core formats using a single-parity check bit transmitted in one quadrature of one polarization in one of the cores and polarization-division multiplexing quadrature phase shift keying data in all remaining cores. We observe that for high core counts, an advantage of almost 3 dB in asymptotic power efficiency may be obtained with negligible impact on spectral efficiency, which translates into experimentally measured reduction in the required optical signal-to-noise ratio of up to 1.8 dB at a bit-error-rate of 10-5 and the same data-rate, and additional transmission reach of up to 20%.


Assuntos
Tecnologia de Fibra Óptica/instrumentação , Interferometria/instrumentação , Dispositivos Ópticos , Processamento de Sinais Assistido por Computador/instrumentação , Telecomunicações/instrumentação , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento
4.
Mol Psychiatry ; 18(10): 1096-105, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23032875

RESUMO

Cognitive impairments are common in depression and involve dysfunctional serotonin neurotransmission. The 5-HT1B receptor (5-HT(1B)R) regulates serotonin transmission, via presynaptic receptors, but can also affect transmitter release at heterosynaptic sites. This study aimed at investigating the roles of the 5-HT(1B)R, and its adapter protein p11, in emotional memory and object recognition memory processes by the use of p11 knockout (p11KO) mice, a genetic model for aspects of depression-related states. 5-HT(1B)R agonist treatment induced an impairing effect on emotional memory in wild type (WT) mice. In comparison, p11KO mice displayed reduced long-term emotional memory performance. Unexpectedly, 5-HT(1B)R agonist stimulation enhanced memory in p11KO mice, and this atypical switch was reversed after hippocampal adeno-associated virus mediated gene transfer of p11. Notably, 5-HT(1B)R stimulation increased glutamatergic neurotransmission in the hippocampus in p11KO mice, but not in WT mice, as measured by both pre- and postsynaptic criteria. Magnetic resonance spectroscopy demonstrated global hippocampal reductions of inhibitory GABA, which may contribute to the memory enhancement and potentiation of pre- and post-synaptic measures of glutamate transmission by a 5-HT(1B)R agonist in p11KO mice. It is concluded that the level of hippocampal p11 determines the directionality of 5-HT(1B)R action on emotional memory processing and modulates hippocampal functionality. These results emphasize the importance of using relevant disease models when evaluating the role of serotonin neurotransmission in cognitive deficits related to psychiatric disorders.


Assuntos
Anexina A2/fisiologia , Aprendizagem da Esquiva/fisiologia , Emoções/fisiologia , Hipocampo/fisiologia , Memória/fisiologia , Receptor 5-HT1B de Serotonina/fisiologia , Proteínas S100/fisiologia , Animais , Anexina A2/deficiência , Anexina A2/genética , Aprendizagem da Esquiva/efeitos dos fármacos , Depressão/fisiopatologia , Modelos Animais de Doenças , Comportamento Exploratório/efeitos dos fármacos , Comportamento Exploratório/fisiologia , Feminino , Genes Reporter , Ácido Glutâmico/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ressonância Magnética Nuclear Biomolecular , Fosforilação/efeitos dos fármacos , Terminações Pré-Sinápticas/metabolismo , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Piridinas/farmacologia , Tempo de Reação , Receptores de AMPA/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Proteínas S100/deficiência , Proteínas S100/genética , Agonistas do Receptor 5-HT1 de Serotonina/farmacologia , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologia , Transdução Genética
5.
J Dairy Sci ; 97(7): 4471-84, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24835966

RESUMO

Large variation exists in the potassium content of dairy cow feeds and also within a feed type due to soil type and fertilization. Increased ration K concentration causes a subsequent increase in urinary volume and could be expected to also lower milk urea concentration. Six multiparous mid-lactation Swedish Red dairy cows, all fitted with rumen cannulas, were subjected to 3 different levels of K intake in a Latin square experiment with three 2-wk periods to evaluate the effects on concentrations of milk urea and rumen ammonia, urinary output, and drinking water intake. The treatments were achieved by K supplementation on top of a low-K basal ration fed at individual allowances fixed throughout the experiment. The basal ration, consumed at 20.2 kg of dry matter (DM)/d, provided 165 g of crude protein/kg of DM and consisted of grass silage, concentrates, and urea in the proportions 39.3:60.0:0.7 on a DM basis. Potassium bicarbonate supplementation was 0, 616, and 1,142 g/d, respectively, to give total ration K concentrations that were low (LO; 12 g/kg of DM), medium (MED; 23 g/kg of DM), or high (HI; 32 g/kg of DM). Production and composition of milk was not affected by treatment. A linear effect on milk urea concentration was detected, being 4.48, 4.18, and 3.77 mM for LO, MED, and HI, respectively, and a linear tendency for rumen ammonia concentration with 6.65, 6.51, and 5.84 mg of NH3-N/dL for LO, MED, and HI, respectively. Milk urea concentration peaked about 3h after the rumen ammonia peak from the morning feeding, at a level 1.3mM over the baseline. Urinary urea excretion declined linearly (105, 103, and 98 g of urea-N/d for LO, MED, and HI, respectively). Linear increases occurred in urinary output (0.058 ± 0.001 kg of urine/g of K intake; no intercept; coefficient of determination=0.997) and drinking water intake (65.9 ± 2.02 + 0.069 ± 0.004 kg of water/g of K intake; coefficient of determination=0.95). Urinary K concentration leveled off at 12.4 g/L. Urinary creatinine excretion was not affected by K addition, but allantoin excretion increased linearly by 27% from LO to HI, suggesting increased rumen microbial growth. Rumen pH, acetate proportion of total volatile fatty acids, and digestibility of DM, organic matter, and neutral detergent fiber increased linearly with increasing potassium intake. We concluded that increased ration K concentration lowers milk urea concentration with a magnitude significant for the interpretation of milk urea values, but other sources of variation, such as sampling time relative to feeding, may be even more important.


Assuntos
Bicarbonatos/administração & dosagem , Bovinos/fisiologia , Ingestão de Líquidos , Leite/química , Compostos de Potássio/administração & dosagem , Ureia/urina , Amônia/urina , Animais , Dieta/veterinária , Fibras na Dieta/administração & dosagem , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Ácidos Graxos Voláteis/análise , Feminino , Lactação/efeitos dos fármacos , Modelos Lineares , Poaceae , Rúmen/metabolismo , Silagem
6.
Mol Psychiatry ; 17(2): 173-84, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21242991

RESUMO

Cognitive dysfunctions are common in major depressive disorder, but have been difficult to recapitulate in animal models. This study shows that Flinders sensitive line (FSL) rats, a genetic rat model of depression, display a pronounced impairment of emotional memory function in the passive avoidance (PA) task, accompanied by reduced transcription of Arc in prefrontal cortex and hippocampus. At the cellular level, FSL rats have selective reductions in levels of NMDA receptor subunits, serotonin 5-HT(1A) receptors and MEK activity. Treatment with chronic escitalopram, but not with an antidepressant regimen of nortriptyline, restored memory performance and increased Arc transcription in FSL rats. Multiple pharmacological manipulations demonstrated that procognitive effects could also be achieved by either disinhibition of 5-HT(1A)R/MEK/Arc or stimulation of 5-HT4R/MEK/Arc signaling cascades. Taken together, studies of FSL rats in the PA task revealed reversible deficits in emotional memory processing, providing a potential model with predictive and construct validity for assessments of procognitive actions of antidepressant drug therapies.


Assuntos
Complexo Relacionado com a AIDS/metabolismo , Depressão/complicações , Emoções/fisiologia , Sistema de Sinalização das MAP Quinases/fisiologia , Transtornos da Memória/etiologia , Receptores de Serotonina/metabolismo , Análise de Variância , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Aprendizagem da Esquiva/fisiologia , Benzopiranos/farmacologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Citalopram/uso terapêutico , Depressão/tratamento farmacológico , Depressão/genética , Modelos Animais de Doenças , Maleato de Dizocilpina/farmacologia , Inibidores Enzimáticos/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Comportamento Exploratório/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Hipocampo/metabolismo , Imunoprecipitação , Sistema de Sinalização das MAP Quinases/genética , Transtornos da Memória/tratamento farmacológico , Transtornos da Memória/patologia , Córtex Pré-Frontal/metabolismo , Ratos , Ratos Mutantes , Receptores de N-Metil-D-Aspartato/metabolismo , Serotonina/metabolismo , Inibidores Seletivos de Recaptação de Serotonina/uso terapêutico , Natação/psicologia
7.
Nanotechnology ; 23(2): 025301, 2012 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-22166619

RESUMO

Chemically ordered 5 nm-thick L10 FePtCu films with strong perpendicular magnetic anisotropy were post-patterned by nanoimprint lithography into a dot array over a 3 mm-wide circumferential band on a 3 inch Si wafer. The dots with a diameter of 30 nm and a center-to-center pitch of 60 nm appear as single domain and reveal an enhanced switching field as compared to the continuous film. We demonstrate successful recording on a single track using shingled writing with a conventional hard disk drive write/read head.

8.
J Clin Pharm Ther ; 37(6): 686-92, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22924464

RESUMO

WHAT IS KNOWN AND OBJECTIVE: Interventions involving medication reconciliation and review by clinical pharmacists can reduce drug-related problems and improve therapeutic outcomes. The objective of this study was to examine the impact of routine admission medication reconciliation and inpatient medication review on emergency department (ED) revisits after discharge. Secondary outcomes included the combined rate of post-discharge hospital revisits or death. METHODS: This prospective, controlled study included all patients hospitalized in three internal medicine wards in a university hospital, between 1 January 2006 and 31 May 2008. Medication reconciliation on admission and inpatient medication review, conducted by clinical pharmacists in a multiprofessional team, were implemented in these wards at different times during 2007 and 2008 (intervention periods). A discharge medication reconciliation was undertaken in all the study wards, during both control and intervention periods. Patients were included in the intervention group (n = 1216) if they attended a ward with medication reconciliation and review, whether they had received the intervention or not. Control patients (n = 2758) attended the wards before implementation of the intervention. RESULTS AND DISCUSSION: No impact of medication reconciliation and reviews on ED revisits [hazard ratio (HR), 0.95; 95% confidence interval (CI), 0.86-1.04]or event-free survival (HR, 0.96; 95% CI, 0.88-1.04) was demonstrated. In the intervention group, 594 patients (48.8%) visited the ED, compared with 1416 (51.3%) control patients. In total, 716 intervention (58.9%) and 1688 (61.2%) control patients experienced any event (ED visit, hospitalization or death). Because the time to a subsequent ED visit was longer for the control as well as the intervention groups in 2007 than in 2006 (P < 0.05), we re-examined this cohort of patients; the proportion of patients revisiting the ED was similar in both groups in 2007 (P = 0.608). WHAT IS NEW AND CONCLUSION: Routine implementation of medication reconciliation and reviews on admission and during the hospital stay did not appear to have any impact on ED revisits, re-hospitalizations or mortality over 6-month follow-up.


Assuntos
Revisão de Uso de Medicamentos/métodos , Serviço Hospitalar de Emergência/estatística & dados numéricos , Reconciliação de Medicamentos/métodos , Farmacêuticos/organização & administração , Idoso , Feminino , Seguimentos , Hospitalização/estatística & dados numéricos , Hospitais Universitários , Humanos , Masculino , Conduta do Tratamento Medicamentoso/organização & administração , Pessoa de Meia-Idade , Admissão do Paciente , Equipe de Assistência ao Paciente , Alta do Paciente , Readmissão do Paciente/estatística & dados numéricos , Serviço de Farmácia Hospitalar/organização & administração , Estudos Prospectivos , Fatores de Tempo
9.
Open Res Eur ; 2: 106, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-37982077

RESUMO

Beyond fifth generation (5G) communication systems aim towards data rates in the tera bits per second range, with improved and flexible coverage options, introducing many new technological challenges in the fields of network architecture, signal pro- cessing, and radio frequency front-ends. One option is to move towards cell-free, or distributed massive Multiple-Input Multiple-Output (MIMO) network architectures and highly integrated front-end solutions. This paper presents an outlook on be- yond 5G distributed massive MIMO communication systems, the signal processing, characterisation and simulation challenges, and an overview of the state of the art in millimetre wave antennas and electronics.

10.
Nat Med ; 4(11): 1313-7, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9809557

RESUMO

The genesis of new cells, including neurons, in the adult human brain has not yet been demonstrated. This study was undertaken to investigate whether neurogenesis occurs in the adult human brain, in regions previously identified as neurogenic in adult rodents and monkeys. Human brain tissue was obtained postmortem from patients who had been treated with the thymidine analog, bromodeoxyuridine (BrdU), that labels DNA during the S phase. Using immunofluorescent labeling for BrdU and for one of the neuronal markers, NeuN, calbindin or neuron specific enolase (NSE), we demonstrate that new neurons, as defined by these markers, are generated from dividing progenitor cells in the dentate gyrus of adult humans. Our results further indicate that the human hippocampus retains its ability to generate neurons throughout life.


Assuntos
Giro Denteado/fisiologia , Hipocampo/fisiologia , Regeneração Nervosa , Neurônios/fisiologia , Adulto , Animais , Astrócitos/citologia , Astrócitos/patologia , Astrócitos/fisiologia , Biomarcadores/análise , Bromodesoxiuridina , Calbindinas , DNA/biossíntese , Giro Denteado/citologia , Giro Denteado/patologia , Proteína Glial Fibrilar Ácida/análise , Haplorrinos , Hipocampo/citologia , Hipocampo/patologia , Humanos , Proteínas do Tecido Nervoso/análise , Neurônios/citologia , Neurônios/patologia , Fosfopiruvato Hidratase/análise , Roedores , Proteína G de Ligação ao Cálcio S100/análise , Células-Tronco/citologia , Células-Tronco/patologia , Células-Tronco/fisiologia
11.
Radiat Prot Dosimetry ; 127(1-4): 444-8, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17545661

RESUMO

This paper describes the objectives, and reviews the progress, of the European project 'Treatment Initiatives After Radiological Accidents' (TIARA). TIARA forms part of the 'Preparatory Action for Security Research' (PASR) launched by the European Commission in 2004. The Preparatory Action is intended to reach preliminary conclusions on the needs for the security of EU citizens. It prepared a comprehensive Security Research Programme as part of the Commission's Seventh Framework Programme proposal, which was adopted in 2006 and launched in 2007. The principal purpose of TIARA is to constitute a European network that will participate in facilitating the management of a crisis in the event of the malevolent dispersal of radionuclides into the public environment.


Assuntos
Cuidados Críticos/métodos , Cuidados Críticos/organização & administração , União Europeia/organização & administração , Lesões por Radiação/diagnóstico , Lesões por Radiação/terapia , Protetores contra Radiação/administração & dosagem , Liberação Nociva de Radioativos/prevenção & controle , Humanos
12.
Neuroscience ; 142(4): 963-78, 2006 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-16952425

RESUMO

Cholinergic and GABAergic neurons in the medial septal/vertical limb of the diagonal band of Broca (MS/vDB) area project to the hippocampus and constitute the septohippocampal pathway, which has been implicated in learning and memory. There is also evidence for extrinsic and intrinsic glutamatergic neurons in the MS/vDB, which by regulating septohippocampal neurons can influence hippocampal functions. The potential role of glutamatergic N-methyl-D-aspartate (NMDA) receptors within the MS/vDB for spatial and emotional learning was studied using the water maze and step-through passive avoidance (PA) tasks, which are both hippocampal-dependent. Blockade of septal NMDA receptors by infusion of the competitive NMDA receptor antagonist D-(-)-2-amino-5-phosphonopentanoic acid (D-AP5) (0.3-5 microg/rat), infused 15 min prior to training, impaired spatial learning and memory at the 5 microg dose of D-AP5, while doses of 0.3 and 1 microg per rat had no effect. The impairment in spatial learning appears not to be caused by sensorimotor or motivational disturbances, or anxiogenic-like behavior. Thus, d-AP5-treated rats were not impaired in swim performance or visuospatial abilities and spent more time in the open arms of the elevated plus-maze. In the PA task, intraseptal D-AP5 infused 15 min before training impaired retention as examined 24 h after training. This impairment was observed already at the 0.3 microg dose, suggesting that NMDA receptors within the MS/vDB may be more important for emotional than spatial memory. In summary, the present data indicate that changes in septal glutamate transmission and NMDA receptor activity can influence activity-dependent synaptic plasticity in the hippocampus and thereby learning and memory.


Assuntos
Emoções/fisiologia , Aprendizagem/fisiologia , Vias Neurais/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Núcleos Septais/metabolismo , Percepção Espacial/fisiologia , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Aprendizagem da Esquiva/fisiologia , Relação Dose-Resposta a Droga , Emoções/efeitos dos fármacos , Antagonistas de Aminoácidos Excitatórios/farmacologia , Ácido Glutâmico/metabolismo , Aprendizagem/efeitos dos fármacos , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Vias Neurais/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Plasticidade Neuronal/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Núcleos Septais/efeitos dos fármacos , Percepção Espacial/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologia
13.
Doc Ophthalmol ; 113(3): 179-86, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17111186

RESUMO

PURPOSE: To evaluate retinal function and histopathology in rabbits treated orally with the anti-epileptic drug topiramate. METHODS: Six rabbits were treated with a daily oral dose of topiramate during a period of eight months. Six rabbits receiving water served as controls. Blood samples were analyzed for determination of topiramate serum levels in order to ensure successful drug exposition. Standardized full-field electroretinograms (ERGs) were performed before treatment and then at 2, 3 and 8 months during the treatment period. After terminating treatment the rabbits were sacrificed and the morphology of the sectioned retina was studied. RESULTS: After eight months of treatment the full-field ERG demonstrated normal rod function in treated and control rabbits, but the light adapted 30 Hz flicker b-wave amplitude was significantly reduced in the treated rabbits. This was the case for both the light adapted (Wilcoxon signed ranks test, P = 0.046) and the dark adapted (Wilcoxon signed ranks test, P = 0.028) 30 Hz flicker response from the treated rabbits. Retinal immunohistology revealed a severe accumulation of GABA in amacrine cells and in the inner plexiform layer in 4 of 6 treated rabbits compared to the controls. CONCLUSIONS: Topiramate, orally administrated to rabbits, may cause a significant reduction of the retinal function demonstrated by the reduced b-wave amplitude in the full-field ERG, as well as changes in immunohistology characterized by a severe accumulation of GABA in the inner retina. The retinal dysfunction and the morphological changes indicate that topiramat may damage the retina, similarly to vigabatrin (another anti-epileptic drug).


Assuntos
Anticonvulsivantes/farmacologia , Eletrorretinografia , Frutose/análogos & derivados , Retina/efeitos dos fármacos , Retina/patologia , Adaptação Ocular , Administração Oral , Células Amácrinas/metabolismo , Animais , Anticonvulsivantes/administração & dosagem , Adaptação à Escuridão , Esquema de Medicação , Frutose/administração & dosagem , Frutose/farmacologia , Imuno-Histoquímica , Estimulação Luminosa/métodos , Coelhos , Retina/metabolismo , Retina/fisiopatologia , Distribuição Tecidual , Topiramato , Ácido gama-Aminobutírico/metabolismo
14.
Ultrasonics ; 65: 242-8, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26472055

RESUMO

A unimorph flexural transducer design is proposed and tested with regard to mode shapes and frequencies. The transducers consist of a passive metal cap structure, and a thin piezoelectric disc, rigidly bonded to the inside. Extensive finite element (FE) modelling, and experimental 2D, time-resolved displacement measurements were done to characterise the transducers flexural properties, and to compare them to the analytical solutions of thin vibrating plates. Emphasis was put on characterising the passive layer of the unimorph structure, before bonding the piezoelectric element, to understand how the active element affects the behaviour of the flexing plate. A high power Nd:YAG laser was used to actuate the metal plate (non-contact), and the frequency content of the resulting displacement signal was analysed to identify the flexural modes. The non-axisymmetric modes, which are conventionally disregarded because of their unfavourable acoustic properties, were also taken into account. There was excellent agreement between the experimental results and the FE simulation data. There was good agreement with the analytical edge clamped plate model, but with some notable deviations, which have not previously been identified or commented upon. Specifically, the second axisymmetric mode is split into three separate modes, which is not explained by the traditional theory of vibrating plates.

15.
Cell Death Differ ; 11(11): 1166-78, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15243583

RESUMO

One hemisphere of postnatal day 8 (P8) rats or P10 mice was irradiated with a single dose of 4-12 Gy, and animals were killed from 2 h to 8 weeks after irradiation (IR). In the subventricular zone (SVZ) and the granular cell layer (GCL) of the dentate gyrus, harboring neural and other progenitor cells, nitrosylation and p53 peaked 2-12 h after IR, followed by markers for active caspase-3, apoptosis-inducing factor and TUNEL (6-24 h). Ki67-positive (proliferating) cells had disappeared by 12 h and partly reappeared by 7 days post-IR. The SVZ and GCL areas decreased approximately 50% 7 days after IR. The development of white matter was hampered, resulting in 50-70% less myelin basic protein staining. Pretreatment with erythropoietin did not confer protection against IR. Caspase inhibition by overexpression of XIAP prevented caspase-9 and caspase-3 activation but not cell death, presumably because of increased caspase-independent cell death.


Assuntos
Encéfalo/embriologia , Inibidores de Caspase , Inibidores Enzimáticos/farmacologia , Eritropoetina/farmacologia , Células-Tronco/patologia , Transporte Ativo do Núcleo Celular , Animais , Apoptose , Peso Corporal , Caspase 3 , Caspase 9 , Caspases/metabolismo , Morte Celular , Proliferação de Células , Fragmentação do DNA , Relação Dose-Resposta à Radiação , Ativação Enzimática , Eritropoetina/metabolismo , Hipocampo/metabolismo , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Antígeno Ki-67/biossíntese , Camundongos , Camundongos Endogâmicos C57BL , Proteína Básica da Mielina/metabolismo , Proteínas/metabolismo , Ratos , Ratos Wistar , Fatores de Tempo , Proteína Supressora de Tumor p53/metabolismo , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X
16.
J Mol Biol ; 216(2): 223-8, 1990 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-2254923

RESUMO

Small-angle neutron-scattering (SANS) and ultraviolet linear dichroism (l.d.) were measured on identical samples of a RecA-double-stranded (ds) DNA complex, including cofactor adenosine 5'-O-thiotriphosphate, which were aligned by flow in two equivalent Couette devices made of niobium and silica, transparent to neutrons and to ultraviolet light, respectively. The SANS anisotropy indicates a modest orientation of the RecA-dsDNA fiber with the helix axis parallel to the flow field. By correlation with the corresponding l.d. of the DNA at the same orientation conditions, it is inferred that the DNA bases have a local orientation that is approximately perpendicular to the helix axis. By comparison with the worse orientation in single-stranded DNA-RecA, this conclusion suggests that the dsDNA in its complex with RecA is not strand separated, and may be accommodated as an essentially unperturbed, straight double helix running along the RecA polymer fiber. The SANS anisotropy is also found to support the assignment of a subsidiary intensity maximum as originating from the pitch of a helical fiber.


Assuntos
DNA/metabolismo , Recombinases Rec A/metabolismo , Animais , Bovinos , Modelos Moleculares , Nêutrons , Conformação de Ácido Nucleico , Ligação Proteica , Conformação Proteica , Espalhamento de Radiação , Espectrofotometria Ultravioleta , Timo
17.
Br J Radiol ; 88(1047): 20140586, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25494657

RESUMO

OBJECTIVE: To investigate the impact of including fluorine-18 fludeoxyglucose ((18)F-FDG) positron emission tomography (PET) scanning in the planning of paediatric radiotherapy (RT). METHODS: Target volumes were first delineated without and subsequently re-delineated with access to (18)F-FDG PET scan information, on duplicate CT sets. RT plans were generated for three-dimensional conformal photon RT (3DCRT) and intensity-modulated proton therapy (IMPT). The results were evaluated by comparison of target volumes, target dose coverage parameters, normal tissue complication probability (NTCP) and estimated risk of secondary cancer (SC). RESULTS: Considerable deviations between CT- and PET/CT-guided target volumes were seen in 3 out of the 11 patients studied. However, averaging over the whole cohort, CT or PET/CT guidance introduced no significant difference in the shape or size of the target volumes, target dose coverage, irradiated volumes, estimated NTCP or SC risk, neither for IMPT nor 3DCRT. CONCLUSION: Our results imply that the inclusion of PET/CT scans in the RT planning process could have considerable impact for individual patients. There were no general trends of increasing or decreasing irradiated volumes, suggesting that the long-term morbidity of RT in childhood would on average remain largely unaffected. ADVANCES IN KNOWLEDGE: (18)F-FDG PET-based RT planning does not systematically change NTCP or SC risk for paediatric cancer patients compared with CT only. 3 out of 11 patients had a distinct change of target volumes when PET-guided planning was introduced. Dice and mismatch metrics are not sufficient to assess the consequences of target volume differences in the context of RT.


Assuntos
Simulação por Computador , Neoplasias/radioterapia , Tomografia por Emissão de Pósitrons/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Tomografia Computadorizada por Raios X/métodos , Adolescente , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Masculino , Neoplasias/diagnóstico por imagem , Fótons/uso terapêutico , Terapia com Prótons , Dosagem Radioterapêutica , Estudos Retrospectivos
18.
Biol Psychiatry ; 46(6): 850-5, 1999 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-10494455

RESUMO

BACKGROUND: Rescue service personnel are often exposed to traumatic events as part of their occupation, and higher prevalence rates of psychiatric illness have been found among this group. METHODS: In 65 rescue workers, salivary cortisol at 8 AM and 10 PM and serum prolactin at 8 AM were related to the psychiatric self-rating scale General Health Questionnaire (GHQ-28) measuring psychiatric health, and the Impact of Events Scale (IES) and Post Traumatic Symptom Scale (PTSS) measuring posttraumatic symptoms. RESULTS: Seventeen percent of the study population scored above the GHQ-28 cut-off limit but none scored beyond the cut-off limit in the IES and PTSS questionnaires. Salivary cortisol concentration at 10 PM correlated with statistical significance to anxiety (p < .005) and depressive symptoms (p < .01) measured with GHQ-28, as well as to posttraumatic symptoms, with avoidance behavior measured with IES (p < .01) and PTSS (p < .005). Two of the rescue workers were followed over time with the same sampling procedure after a major rescue commission. CONCLUSIONS: The correlation between evening salivary cortisol and anxiety, depressiveness, and posttraumatic avoidance symptoms indicates that these parameters can be used in screening and follow-up after traumatic stress events.


Assuntos
Hidrocortisona/análise , Prolactina/sangue , Trabalho de Resgate , Saliva/química , Estresse Psicológico/metabolismo , Adulto , Biomarcadores , Ritmo Circadiano/fisiologia , Seguimentos , Indicadores Básicos de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários
19.
Biol Psychiatry ; 50(12): 986-93, 2001 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-11750895

RESUMO

BACKGROUND: Because traumatic events are unpredictable, there are few studies of psychobiological states immediately following such events. Our study aimed to determine the relation of salivary cortisol to psychologic distress immediately after a traumatic event and then during follow-up. METHODS: Measurement of morning and evening salivary cortisol and ratings of psychologic distress (using the Impact of Events Scale [IES], the Post Traumatic Symptom Scale, and the General Health Questionnaire) were performed with 31 United Nations soldiers at three time points--5 days and 2 and 9 months--following a mine accident in Lebanon. RESULTS: Five days after the accident, 15 subjects reported substantial posttraumatic distress according to the IES, as well as significantly lower morning and higher evening cortisol levels compared with the low-impact group. Within 9 months, the posttraumatic distress of the high-impact group was reduced, accompanied by an increase in morning and a decrease in evening cortisol levels. There were significant relationships between evening cortisol and all rating scales at the first and third time points. CONCLUSIONS: Subclinical posttraumatic stress following an adverse event can be measured biologically via salivary cortisol levels soon after the event.


Assuntos
Distúrbios de Guerra/metabolismo , Hidrocortisona/metabolismo , Saliva/metabolismo , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Sobreviventes/estatística & dados numéricos , Doença Aguda , Adulto , Ritmo Circadiano , Distúrbios de Guerra/psicologia , Seguimentos , Nível de Saúde , Humanos , Masculino , Escalas de Graduação Psiquiátrica , Trabalho de Resgate , Transtornos de Estresse Pós-Traumáticos/metabolismo , Sobreviventes/psicologia , Recursos Humanos
20.
Neurology ; 38(8): 1245-8, 1988 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-3135513

RESUMO

Administration of a low-protein diet to parkinsonian patients with "on-off" syndromes consistently increased the total daily time of "on" states when compared with a high-protein diet. The clinical effect of the low-protein diet may be due to a marked decrease in the plasma concentration of large neutral amino acids that compete with L-dopa for carrier-mediated transport into the brain.


Assuntos
Aminoácidos/sangue , Di-Hidroxifenilalanina/sangue , Doença de Parkinson/sangue , Idoso , Aminoácidos/metabolismo , Di-Hidroxifenilalanina/metabolismo , Interações Medicamentosas , Humanos , Masculino , Doença de Parkinson/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA