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1.
Phys Rev Lett ; 130(12): 122502, 2023 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-37027859

RESUMO

The excited states of N=44 ^{74}Zn were investigated via γ-ray spectroscopy following ^{74}Cu ß decay. By exploiting γ-γ angular correlation analysis, the 2_{2}^{+}, 3_{1}^{+}, 0_{2}^{+}, and 2_{3}^{+} states in ^{74}Zn were firmly established. The γ-ray branching and E2/M1 mixing ratios for transitions deexciting the 2_{2}^{+}, 3_{1}^{+}, and 2_{3}^{+} states were measured, allowing for the extraction of relative B(E2) values. In particular, the 2_{3}^{+}→0_{2}^{+} and 2_{3}^{+}→4_{1}^{+} transitions were observed for the first time. The results show excellent agreement with new microscopic large-scale shell-model calculations, and are discussed in terms of underlying shapes, as well as the role of neutron excitations across the N=40 gap. Enhanced axial shape asymmetry (triaxiality) is suggested to characterize ^{74}Zn in its ground state. Furthermore, an excited K=0 band with a significantly larger softness in its shape is identified. A shore of the N=40 "island of inversion" appears to manifest above Z=26, previously thought as its northern limit in the chart of the nuclides.

2.
Clin Radiol ; 78(7): 518-524, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37085338

RESUMO

AIM: To assess the utility of magnetic resonance imaging (MRI) in addition to the additive benefit of the conventional imaging techniques, computed tomography (CT) and nuclear medicine (NM) bone scintigraphy, for investigation of biochemical recurrence (BCR) post-prostatectomy where access to prostate specific membrane antigen (PSMA) positron-emission tomography (PET)-CT is challenging. MATERIALS AND METHODS: Relevant imaging over a 5-year period was reviewed. Ethical approval was granted by the internal review board. All patients with suspected BCR, defined as a PSA ≥0.2 ng/ml on two separate occasions, underwent a retrospective imaging review. This was performed on PACS archive search database in a single centre using search terms "PSA" and "prostatectomy" in the three imaging methods; MRI, CT, and NM bone scintigraphy. All PSMA PET CT performed were recorded. RESULTS: One hundred and eighty-five patients were identified. Patients with an MRI pelvis that demonstrated distant metastases (i.e., pelvic bone metastases or lymph node involvement more cranial to the bifurcation of the common iliac arteries) were more likely to have a positive CT and/or NM bone scintigraphy. The Pearson correlation coefficient between the findings of M1 disease at MRI pelvis and the presence of distant metastases at CT thorax, abdomen, pelvis and NM bone scintigraphy was calculated at 0.81 (p<0.01) and 0.91 (p<0.01) respectively. CONCLUSION: An imaging strategy based on risk stratification and technique-specific selection criteria leads to more appropriate use of resources, and in turn, increases the yield of conventional imaging methods. MRI prostate findings can be used to predict the additive value of CT/NM bone scintigraphy allowing a more streamlined approach to their use.


Assuntos
Imageamento por Ressonância Magnética , Neoplasias da Próstata , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/fisiopatologia , Imageamento por Ressonância Magnética/normas , Estudos Retrospectivos , Antígeno Prostático Específico/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Idoso , Cintilografia/normas , Fatores de Risco , Tomografia por Emissão de Pósitrons/normas
3.
J R Army Med Corps ; 163(3): 215-219, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27940985

RESUMO

OBJECTIVES: Lisfranc injuries are relatively uncommon midfoot injuries disproportionately affecting young, active males. Previous studies in civilian populations have reported relatively good results with operative treatment. However, treatment results have not been specifically examined in military personnel, who may have higher physical demands than the general population. The purpose of this study was to examine rates of return to military duty following surgical treatment of isolated Lisfranc injuries. METHODS: Surgical records and radiographic images from all active duty US military personnel treated for an isolated Lisfranc injury between January 2005 and July 2014 were examined. Demographic information, injury data, surgical details and subsequent return to duty information were recorded. The primary outcome was ability to return to unrestricted military duty following treatment. The secondary outcome was secondary conversion to a midfoot arthrodesis following initial open reduction internal fixation. RESULTS: Twenty-one patients meeting inclusion criteria were identified. Median patient age was 23 years, and mean follow-up was 43 months. Within this cohort, 14 patients were able to return to military service, while seven required a disability separation from the armed forces. Of the 18 patients who underwent initial fixation, eight were subsequently revised to midfoot arthrodesis for persistent pain. DISCUSSION: Military personnel sustaining Lisfranc injuries have high rates of persistent pain and disability, even after optimal initial surgical treatment. Military surgeons should counsel patients on the career-threatening nature of this condition and high rates of secondary procedures.


Assuntos
Traumatismos do Pé/cirurgia , Ossos do Metatarso/cirurgia , Militares , Retorno ao Trabalho , Ossos do Tarso/cirurgia , Adulto , Feminino , Fixação Interna de Fraturas , Humanos , Masculino , Ossos do Metatarso/lesões , Estudos Retrospectivos , Ossos do Tarso/lesões , Adulto Jovem
4.
J Intellect Disabil Res ; 58(6): 572-82, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23718278

RESUMO

BACKGROUND: The developmental disorder Williams syndrome (WS) is characterised by a distinctive cognitive profile and an intriguing social phenotype. Individuals with the disorder are often highly social engaging with familiar and unfamiliar people and once in an interaction they often show subtle abnormalities of social behaviour. Atypically increased approach to unfamiliar people is widely reported in the existing literature for both children and adults. Parents frequently report interactions with unfamiliar people as a major concern. METHODS: In this study we aimed to evaluate 'stranger danger' awareness using a video vignette task with individuals who had WS. When linked to other components of the WS phenotype (e.g. reduced intellectual ability, increased social approach) an awareness of stranger danger is particularly important. RESULTS: Qualitative and quantitative data showed that young people with WS have difficulties making judgements about whether or not to trust and engage in conversation with unfamiliar people. Qualitative data showed that individuals with WS often suggested that they would engage in an interaction with an unfamiliar person. CONCLUSIONS: The findings have substantial implications for the safety of young people with the disorder and emphasise the need for intervention regarding this behaviour.


Assuntos
Conscientização , Comportamento Perigoso , Relações Interpessoais , Comportamento Social , Confiança , Síndrome de Williams/psicologia , Adolescente , Criança , Comunicação , Feminino , Humanos , Inteligência , Julgamento , Masculino , Habilidades Sociais , Gravação em Vídeo , Síndrome de Williams/diagnóstico
5.
Sci Total Environ ; 934: 172806, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38772795

RESUMO

In response to the plastic waste crisis, teabag producers have substituted the petrochemical-plastic content of their products with bio-based, biodegradable polymers such as polylactic acid (PLA). Despite widespread use, the degradation rate of PLA/PLA-blended materials in natural soil and their effects on soil biota are poorly understood. This study examined the percentage mass deterioration of teabags with differing cellulose:PLA compositions following burial (-10 cm depth) in an arable field margin for 7-months, using a suite of analytical techniques, such as size exclusion chromatography, 1H nuclear magnetic resonance, dynamic scanning calorimetry, and scanning electron microscopy. The effect of 28-d exposure to teabag discs at environmentally relevant concentrations (0.02 %, 0.04 % and 0.07 % w/w) on the survival, growth and reproduction (OECD TG 222 protocol) of the key soil detritivore Eisenia fetida was assessed in laboratory trials. After 7-month burial, Tbag-A (2.4:1 blend) and Tbag-B (3.5:1 cellulose:PLA blend) lost 66 ± 5 % and 78 ± 4 % of their total mass, primarily attributed to degradation of cellulose as identified by FTIR spectroscopy and a reduction in the cellulose:PLA mass ratio, while Tbag-C (PLA) remained unchanged. There were clear treatment and dose-specific effects on the growth and reproductive output of E. fetida. At 0.07 % w/w of Tbag-A adult mortality marginally increased (15 %) and both the quantity of egg cocoons and the average mass of juveniles also increased, while at concentrations ≥0.04 % w/w of Tbag-C, the quantity of cocoons was suppressed. Adverse effects are comparable to those reported for non-biodegradable petrochemical-based plastic, demonstrating that bio-based PLA does not offer a more 'environmentally friendly' alternative. Our study emphasises the necessity to better understand the environmental fate and ecotoxicity of PLA/PLA-blends to ensure interventions developed through the UN Plastic Pollution Treaty to use alternatives and substitutes to conventional plastics do not result in unintended negative consequences.


Assuntos
Oligoquetos , Poliésteres , Poluentes do Solo , Animais , Oligoquetos/fisiologia , Poluentes do Solo/toxicidade , Plásticos , Solo/química
6.
Ann Bot ; 112(4): 671-6, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23380239

RESUMO

BACKGROUND AND AIMS: Despite recent recognition that (1) plant-herbivore interactions during the establishment phase, (2) ontogenetic shifts in resource allocation and (3) herbivore response to plant volatile release are each pivotal to a comprehensive understanding of plant defence, no study has examined how herbivore olfactory response varies during seedling ontogeny. METHODS: Using a Y-tube olfactometer we examined snail (Helix aspersa) olfactory response to pellets derived from macerated Plantago lanceolata plants harvested at 1, 2, 3, 4, 5, 6 and 8 weeks of age to test the hypothesis that olfactory selection of plants by a generalist herbivore varies with plant age. Plant volatiles were collected for 10 min using solid-phase microextraction technique on 1- and 8-week-old P. lanceolata pellets and analysed by gas chromatography coupled with a mass spectrometer. KEY RESULTS: Selection of P. lanceolata was strongly negatively correlated with increasing age; pellets derived from 1-week-old seedlings were three times more likely to be selected as those from 8-week-old plants. Comparison of plant selection experiments with plant volatile profiles from GC/MS suggests that patterns of olfactory selection may be linked to ontogenetic shifts in concentrations of green leaf volatiles and ethanol (and its hydrolysis derivatives). CONCLUSIONS: Although confirmatory of predictions made by contemporary plant defence theory, this is the first study to elucidate a link between seedling age and olfactory selection by herbivores. As a consequence, this study provides a new perspective on the ontogenetic expression of seedling defence, and the role of seedling herbivores, particularly terrestrial molluscs, as selective agents in temperate plant communities.


Assuntos
Herbivoria , Plantago/química , Olfato , Caramujos/fisiologia , Animais , Plantago/crescimento & desenvolvimento , Plântula/química , Plântula/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/análise
7.
Infection ; 41(1): 135-44, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23160837

RESUMO

PURPOSE: Community-acquired pneumonia (CAP) is the most common infection leading to hospitalization in the USA. The objective of this study was to evaluate management practices for inpatient CAP in relation to Infectious Diseases Society of America/American Thoracic Society (IDSA/ATS) guidelines to identify opportunities for antibiotic and health care resource stewardship. METHODS: This was a retrospective cohort study of adults hospitalized for CAP at a single institution from 15 April 2008 to 31 May 2009. RESULTS: Of the 209 patients with CAP who presented to Denver Health Medical Center during the study period and were hospitalized, 166 (79 %) and 43 (21 %) were admitted to a medical ward and the intensive care unit (ICU), respectively. Sixty-one (29 %) patients were candidates for outpatient therapy per IDSA/ATS guidance with a CURB-65 score of 0 or 1 and absence of hypoxemia. Sputum cultures were ordered for 110 specimens; however, an evaluable sample was obtained in only 49 (45 %) cases. Median time from antibiotic initiation to specimen collection was 11 [interquartile range (IQR) 6-19] h, and a potential pathogen was identified in only 18 (16 %) cultures. Blood cultures were routinely obtained for both non-ICU (81 %) and ICU (95 %) cases, but 15 of 36 (42 %) positive cultures were false-positive results. The most common antibiotic regimen was ceftriaxone + azithromycin (182, 87 % cases). Discordant with IDSA/ATS recommendations, oral step-down therapy consisted of a new antibiotic class in 120 (66 %), most commonly levofloxacin (101, 55 %). Treatment durations were typically longer than suggested with a median of 10 (IQR 8-12) days. CONCLUSIONS: In this cohort of patients hospitalized for CAP, management was frequently inconsistent with IDSA/ATS guideline recommendations, revealing potential targets to reduce unnecessary antibiotic and healthcare resource utilization.


Assuntos
Antibacterianos/uso terapêutico , Infecções Comunitárias Adquiridas/diagnóstico , Infecções Comunitárias Adquiridas/tratamento farmacológico , Recursos em Saúde , Pacientes Internados , Pneumonia/diagnóstico , Pneumonia/tratamento farmacológico , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Administração da Prática Médica/normas , Estudos Retrospectivos , Fatores de Risco , Resultado do Tratamento
8.
J Autism Dev Disord ; 52(6): 2656-2669, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34196890

RESUMO

COVID-19 has affected people across the world. The current study examined anxiety and worries during the first UK national lockdown in March 2020. Parents (n = 402) reported on their own anxiety and worries as well as that of their son/daughter with Special Education Needs and Disabilities (SEND) and typically developing (TD) child (n = 186) at three time points. Although both groups showed increased anxiety across the three time points, levels of anxiety in the SEND group, but not the TD siblings, were predicted by awareness about COVID-19. In addition, worries differed between the groups showing that COVID-19 impacts the wellbeing of those with SEND differently to that of their TD siblings.


Assuntos
Transtorno do Espectro Autista , COVID-19 , Ansiedade/epidemiologia , Criança , Controle de Doenças Transmissíveis , Educação Inclusiva , Humanos , SARS-CoV-2 , Reino Unido/epidemiologia
9.
Curr Opin Cell Biol ; 3(2): 206-12, 1991 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1652988

RESUMO

The complexity of receptor-regulated breakdown and modification of phospholipids continues to grow. New developments extend our concepts of signalling enzymes and possible messengers.


Assuntos
Fosfolipases/metabolismo , Fosfolipídeos/metabolismo , Transdução de Sinais , Animais , Substâncias de Crescimento/metabolismo , Humanos , Fosfatos de Inositol/metabolismo , Fosfatidilinositóis/metabolismo , Fosfolipases A/metabolismo , Fosfolipases Tipo C/metabolismo
10.
Nat Med ; 5(1): 83-9, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9883844

RESUMO

The dynamic basis for T-cell depletion in late-stage HIV-1 disease remains controversial. Using a new, non-radioactive, endogenous labeling technique, we report direct measurements of circulating T-cell kinetics in normal and in HIV-1-infected humans. In healthy, HIV-1-seronegative subjects, CD4+ and CD8+ T cells had half-lives of 87 days and 77 days, respectively, with absolute production rates of 10 CD4+ T cells/microl per day and 6 CD8+ T cells/microl per day. In untreated HIV-1-infected subjects (with a mean CD4 level of 342 cells/microl), the half-life of each subpopulation was less than 1/3 as long as those of healthy, HIV-1-seronegative subjects but was not compensated by an increased absolute production rate of CD4+ T cells. After viral replication was suppressed by highly active antiretroviral therapy for 12 weeks, the production rates of circulating CD4+ and CD8+ T cells were considerably elevated; the kinetic basis of increased CD4 levels was greater production, not a longer half-life, of circulating cells. These direct measurements indicate that CD4+ T-cell lymphopenia is due to both a shortened survival time and a failure to increase the production of circulating CD4+ T cells. Our results focus attention on T-cell production systems in the pathogenesis of HIV-1 disease and the response to antiretroviral therapy.


Assuntos
Linfócitos T CD4-Positivos/citologia , Linfócitos T CD8-Positivos/citologia , Infecções por HIV/imunologia , HIV-1/imunologia , Contagem de Linfócito CD4 , Feminino , Infecções por HIV/tratamento farmacológico , Humanos , Cinética , Masculino
11.
Nat Med ; 1(10): 1017-23, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7489356

RESUMO

Haematopoietic stem cells in umbilical cord blood are an attractive target for gene therapy of inborn errors of metabolism. Three neonates with severe combined immunodeficiency were treated by retroviral-mediated transduction of the CD34+ cells from their umbilical cord blood with a normal human adenosine deaminase complementary DNA followed by autologous transplantation. The continued presence and expression of the introduced gene in leukocytes from bone marrow and peripheral blood for 18 months demonstrates that umbilical cord blood cells may be genetically modified with retroviral vectors and engrafted in neonates for gene therapy.


Assuntos
Adenosina Desaminase/deficiência , Adenosina Desaminase/genética , Antígenos CD34/análise , Terapia Genética , Transplante de Células-Tronco Hematopoéticas , Imunodeficiência Combinada Severa/terapia , Adenosina Desaminase/metabolismo , Sequência de Bases , Transfusão de Sangue Autóloga , Medula Óssea/metabolismo , Primers do DNA , Feminino , Sangue Fetal , Vetores Genéticos , Células-Tronco Hematopoéticas/enzimologia , Células-Tronco Hematopoéticas/imunologia , Humanos , Recém-Nascido , Leucócitos/metabolismo , Transfusão de Linfócitos , Masculino , Dados de Sequência Molecular , Retroviridae/enzimologia , Transdução Genética
12.
Clin Med (Lond) ; 11(1): 11-6, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21404775

RESUMO

Transient loss of consciousness (T-LOC), or blackout, is common in acute medicine. Clinical skills are not done well, with at least 74,000 patients misdiagnosed and mistreated for epilepsy in England alone. The aim of this study was to provide a rapid, structured assessment and an electrocardiogram (ECG) for patients with blackouts, aiming to identify high risk, reduce misdiagnoses, reduce hospital admission rates for low-risk patients, diagnose and treat where appropriate, and also provide onward specialist referral. The majority of patients had syncope, and very few had epilepsy. A high proportion had an abnormal ECG. A specialist-nurse-led rapid access blackouts triage clinic (RABTC) provided rapid effective triage for risk, a comprehensive assessment format, direct treatment for many patients, and otherwise a prompt appropriate onward referral. Rapid assessment through a RABTC reduced re-admissions with blackouts. Widespread use of the web-based blackouts tool could provide the NHS with a performance map. The U.K. has low rates of pacing compared to Western Europe, which RABTCs might help correct. The RABTC sits between first responders and specialist referral, providing clinical assessment and ECG in all cases, and referral where appropriate.


Assuntos
Instituições de Assistência Ambulatorial/organização & administração , Epilepsia/diagnóstico , Síncope/diagnóstico , Triagem/métodos , Inconsciência/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Erros de Diagnóstico , Epilepsia/complicações , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Encaminhamento e Consulta , Medição de Risco , Síncope/complicações , Inconsciência/etiologia , Adulto Jovem
13.
Mar Environ Res ; 172: 105482, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34656855

RESUMO

Marine rocky intertidal organisms are amongst those most affected by climate change with regional distributional changes observed for many species. Although often ascribed to increased sea surface temperatures, precise assessment of the local habitat conditions underpinning observed and predicted changes in community assembly is lacking. Here we examine how aspect (i.e. north-south orientation) affects intertidal community composition and how rock surface temperatures and stress responses of two dominant grazer species (Patella spp.) elucidate emergent differences. We quantified year-round temperature variation and surveyed intertidal community composition on paired natural rock gullies with Equator- (EF) and Pole-facing (PF) surfaces. We also investigated variation in limpet (Patella spp.) reproductive phenology and osmotic stress. Average annual temperatures were 0.8 °C (1.6 °C at low tide) higher, with six-fold more frequent extremes (i.e. > 30 °C) on EF than PF surfaces. Intertidal community composition varied with aspect across trophic levels with greater overall species richness, abundance of primary producers and grazers on PF-surfaces, and greater barnacle abundance on EF-surfaces. Although species richness of organisms from different biogeographical origins ('Boreal' or 'Lusitanian') did not vary, the Lusitanian limpet Patella depressa exhibited earlier reproductive development on EF-surfaces and both limpet species exhibited greater thermal stress on EF-surfaces. We argue that our study system provides a good model for understanding how temperature variation at local scales can affect community composition, as well as ecophysiological and ecological responses to climate change and so better inform and predict regional range shifts over coming decades.


Assuntos
Gastrópodes , Thoracica , Animais , Mudança Climática , Ecossistema , Temperatura
14.
Int J Obes (Lond) ; 34(2): 385-95, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19935749

RESUMO

OBJECTIVE: The current set of studies describe the in vivo metabolic actions of the novel amylin-mimetic peptide davalintide (AC2307) in rodents and compares these effects with those of the native peptide. RESEARCH DESIGN AND METHODS: The anti-obesity effects of davalintide were examined after intraperitoneal injection or sustained peripheral infusion through subcutaneously implanted osmotic pumps. The effect of davalintide on food intake after lesioning of the area postrema (AP) and neuronal activation as measured by c-Fos, were also investigated. RESULTS: Similar to amylin, davalintide bound with high affinity to amylin, calcitonin and calcitonin gene-related peptide receptors. Acutely, davalintide displayed greater suppression of dark-cycle feeding and an extended duration of action compared with amylin (23 versus 6 h). Davalintide had no effect on locomotor activity or kaolin consumption at doses that decreased food intake. Davalintide-induced weight loss through infusion was dose dependent, durable up to 8 weeks, fat-specific and lean-sparing, and was associated with a shift in food preference away from high-fat (palatable) chow. Metabolic rate was maintained during active weight loss. Both davalintide and amylin failed to suppress food intake after lesioning of the AP and activated similar brain nuclei, with davalintide displaying an extended duration of c-Fos expression compared with amylin (8 versus 2 h). CONCLUSION: Davalintide displayed enhanced in vivo metabolic activity over amylin while retaining the beneficial properties possessed by the native molecule. In vitro receptor binding, c-Fos expression and AP lesion studies suggest that the metabolic actions of davalintide and amylin occur through activation of similar neuronal pathways.


Assuntos
Amiloide/farmacologia , Depressores do Apetite/farmacologia , Peso Corporal/efeitos dos fármacos , Ingestão de Alimentos/efeitos dos fármacos , Peptídeos/farmacologia , Resposta de Saciedade/efeitos dos fármacos , Aumento de Peso/efeitos dos fármacos , Animais , Peso Corporal/fisiologia , Relação Dose-Resposta a Droga , Ingestão de Alimentos/fisiologia , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Masculino , Ratos , Ratos Sprague-Dawley , Resposta de Saciedade/fisiologia , Aumento de Peso/fisiologia
15.
Org Biomol Chem ; 8(6): 1271-4, 2010 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-20204192

RESUMO

A polymer-bound alpha,beta-methylene-beta-triphosphitylating reagent was synthesized and subjected to reactions with unprotected nucleosides, followed by oxidation, deprotection of cyanoethoxy groups, and acidic cleavage to afford nucleoside 5'-O-alpha,beta-methylene-beta-triphosphates. Among all the compounds, cytidine 5'-O-alpha,beta-methylene-beta-triphosphate inhibited RNase H activity of HIV-1 reverse transcriptase with a K(i) value of 225 microM.


Assuntos
Transcriptase Reversa do HIV/antagonistas & inibidores , HIV-1/enzimologia , Nucleotídeos/síntese química , Nucleotídeos/farmacologia , Inibidores da Transcriptase Reversa/síntese química , Inibidores da Transcriptase Reversa/farmacologia , Transcriptase Reversa do HIV/metabolismo , Cinética , Nucleotídeos/química , Inibidores da Transcriptase Reversa/química , Ribonuclease H/antagonistas & inibidores
16.
J Vet Pharmacol Ther ; 33(2): 189-95, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20444044

RESUMO

Coadministration of grapefruit juice (GFJ) has been proposed to enhance the systemic availability and decrease the required dose of drugs such as cyclosporine that are extensively metabolized in the intestine and liver. Although GFJ inhibits human cytochrome P450 (CYP) 3A, effects on dog CYP have not yet been reported. Consequently, we determined whether GFJ inhibits triazolam hydroxylation by Beagle dog liver microsomes (DLM) using human liver microsomes (HLM) as positive control. Results were compared with the effects of lyophilized GFJ and commercially-available powdered grapefruit capsules, which may be more convenient dosage forms. GFJ inhibited alpha-hydroxytriazolam formation in both DLM and HLM with similar IC(50) (inhibitor concentration producing a 50% decrease in reaction velocity) values of 0.56% and 0.52% (v/v), respectively. Lyophilized GFJ and powdered grapefruit also inhibited DLM alpha-hydroxytriazolam formation with IC(50) values of 0.76 and 1.2 mg/mL, respectively. Consistent with mechanism-based enzyme inhibition, preincubation of DLM with any of the grapefruit products for 20 min resulted in significant enhancement of inhibition of triazolam alpha-hydroxylation by 8-20%. The results indicate that 16 g of lyophilized GFJ or 23 g of powdered grapefruit would be equivalent to dosing 100 mL of GFJ. In vivo pharmacokinetic interaction studies are needed to confirm these in vitro findings.


Assuntos
Citrus paradisi , Inibidores das Enzimas do Citocromo P-450 , Cães/metabolismo , Microssomos Hepáticos/metabolismo , Triazolam/metabolismo , Animais , Bebidas , Sistema Enzimático do Citocromo P-450/metabolismo , Liofilização , Moduladores GABAérgicos/metabolismo , Hidroxilação/efeitos dos fármacos , Masculino , Pós
17.
Science ; 215(4529): 188-90, 1982 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-6171884

RESUMO

A metabolically protected analog of substance P, [pGlu5-MePhe8-MeGly9]SP(5-11) (DiMe-C7), was approximately equipotent with substance P in causing increased locomotor activity after microinfusion into the ventral tegmental area of rat brain, but the effects of DiMe-C7 on behavior were considerably prolonged. There was little metabolic degradation of tritiated DiMe-C7 for up to 1 hour after infusion, whereas tritiated substance P was completely degraded within 10 minutes.


Assuntos
Encéfalo/metabolismo , Fragmentos de Peptídeos , Substância P/análogos & derivados , Animais , Comportamento Animal/efeitos dos fármacos , Atividade Motora/efeitos dos fármacos , Ácido Pirrolidonocarboxílico/análogos & derivados , Ratos , Substância P/metabolismo , Substância P/farmacologia
18.
Heredity (Edinb) ; 102(3): 274-85, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19002205

RESUMO

In plants, pollen- and seed-dispersal distributions are characteristically leptokurtic, with significant consequences for spatial genetic structure and nearest-neighbour mating. However, most studies to date have been on wind- or insect-pollinated species. Here, we assigned paternity to quantify effective pollen dispersal over 9 years of mating, contrasted this to seed dispersal and examined their effects on fine-scale spatial genetic structure, within the bird-pollinated shrub Banksia hookeriana (Proteaceae). We used 163 polymorphic amplified fragment length polymorphism markers to assess genetic structure and pollen dispersal in a spatially discrete population of 112 plants covering 0.56 ha. Spatial autocorrelation analysis detected spatial genetic structure in the smallest distance class of 0-5 m (r=0.025), with no significant structure beyond 8 m. Experimentally quantified seed-dispersal distances for 337 seedlings showed a leptokurtic distribution around a median of 5 m, reaching a distance of 36 m. In marked contrast, patterns of pollen dispersal for 274 seeds departed strikingly from typical near-neighbour pollination, with a distribution largely corresponding to the spatial distribution of plants. We found very high multiple paternity, very low correlated paternity and an equal probability of siring for the 50 closest potential mates. Extensive pollen carryover was demonstrated by multiple siring in 83 of 86 (96.5%) two-seeded fruits. Highly mobile nectar-feeding birds facilitate this promiscuity through observed movements that were effectively random. As the incidence of bird-pollination is markedly greater in the Southwest Australian Floristic Region than elsewhere, our results have broad and novel significance for the evolution and conservation for many species in Gondwanan lineages.


Assuntos
Aves/fisiologia , Pólen/genética , Polinização , Proteaceae/genética , Sementes/genética , Animais , Comportamento Animal , Pólen/fisiologia , Proteaceae/fisiologia , Sementes/fisiologia
19.
Ann Bot ; 103(8): 1347-53, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19351683

RESUMO

BACKGROUND AND AIMS: Although the causes and consequences of seedling herbivory for plant community composition are well understood, the mechanisms by which herbivores influence plant species recruitment to the established phase remain less clear. The aim was to examine how variation in the intensity of seedling herbivory interacts with growth-defence trade-offs and herbivore feeding preferences to affect plant community development. METHODS: Using 14-d-old seedlings of Trifolium pratense and T. repens, relative growth and susceptibility to herbivory by the snail Helix aspersa was quantified to elucidate putative growth-defence trade-offs for these species. Then mixed assemblages of 14-d-old Trifolium seedlings were exposed to herbivory by zero, two, five or ten snails and determined how variation in the intensity of herbivory affected competitive interactions into the mature phase (as measured by total plant biomass at 120 d old). KEY RESULTS: In the absence of herbivory, communities were dominated by T. pratense; a result expected on the basis that it yielded larger and presumably more competitive seedlings. However, when seedlings were exposed to herbivory, the balance of competition shifted. At low levels of herbivory (two snails), both Trifolium species contributed equally to total plant biomass. More intense herbivory (five snails) resulted in almost total mortality of T. pratense and dominance of the mature community by T. repens. The most intense herbivory (ten snails) effectively removed all seedlings from the experimental community. CONCLUSIONS: The study illustrates a mechanism whereby spatio-temporal fluctuations in seedling herbivory, when coupled with species-specific variation in competitive ability and sensitivity to herbivore attack, can differentially influence plant recruitment into the mature phase. This mechanism may be a key element in our attempts to understand plant species coexistence, since fluctuations in plant recruitment are fundamental to the many theories that view coexistence as a consequence of a spatio-temporal lottery for dominance over regeneration micro-sites.


Assuntos
Trifolium/fisiologia , Biomassa , Especificidade da Espécie , Trifolium/crescimento & desenvolvimento
20.
Med Vet Entomol ; 23(1): 26-33, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19067795

RESUMO

Houseflies (Musca domestica L.) are a major pest species of livestock units and landfill sites. Insecticide resistance has resulted in an increased emphasis on lure-and-kill control methods, but the success of this approach relies on the effective attraction of houseflies with olfactory or visual stimuli. This study examined the efficacy of olfactory (cuticular hydrocarbons) or visual (colours and groups of flies) attractants in a commercial poultry unit. Despite simulating the cuticular hydrocarbon profiles of male and female houseflies, we found no significant increase in the number of individuals lured to traps and no sex-specific responses were evident. The use of target colours selected to match the three peaks in housefly visual spectral sensitivity yielded no significant increase in the catch rate of traps to which they were applied. This study also demonstrated that male and female flies possess significantly different spectral reflectance (males are brighter at 320-470 nm; females are brighter at 470-670 nm). An experiment incorporating groups of recently killed flies from which cuticular hydrocarbons were either removed by solvent or left intact also failed to show any evidence of olfactory or visual attraction for houseflies of either sex. This study concluded that variations of the most commonly applied methods of luring houseflies to traps in commercial livestock units fail to significantly increase capture rates. These results support commonly observed inconsistencies associated with using olfactory or visual stimuli in lure-and-kill systems, possibly because field conditions lessen the attractant properties observed in laboratory experiments.


Assuntos
Comportamento Animal , Moscas Domésticas/fisiologia , Hidrocarbonetos/metabolismo , Controle de Insetos/instrumentação , Tegumento Comum/fisiologia , Visão Ocular/fisiologia , Animais , Cor , Feminino , Masculino
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