Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Biol Lett ; 19(8): 20230043, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37554011

RESUMO

Describing individual morphology and growth is key for identifying ecological niches and monitoring the health and fitness of populations. Eastern North Pacific ((ENP), approximately 16 650 individuals) gray whales primarily feed in the Arctic/sub-Arctic regions, while a small subgroup called the Pacific Coast Feeding Group (PCFG, approximately 212 individuals) instead feeds between northern California, USA and British Columbia, Canada. Evidence suggests PCFG whales have lower body condition than ENP whales. Here we investigate morphological differences (length, skull, and fluke span) and compare length-at-age growth curves between ENP and PCFG whales. We use ENP gray whale length-at-age data comprised of strandings, whaling, and aerial photogrammetry (1926-1997) for comparison to data from PCFG whales collected through non-invasive techniques (2016-2022) to estimate age (photo identification) and length (drone-based photogrammetry). We use Bayesian methods to incorporate uncertainty associated with morphological measurements (manual and photogrammetric) and age estimates. We find that while PCFG and ENP whales have similar growth rates, PCFG whales reach smaller asymptotic lengths. Additionally, PCFG whales have relatively smaller skulls and flukes than ENP whales. These findings represent a striking example of morphological adaptation that may facilitate PCFG whales accessing a foraging niche distinct from the Arctic foraging grounds of the broader ENP population.


Assuntos
Ecossistema , Baleias , Animais , Teorema de Bayes , Estações do Ano , Regiões Árticas
2.
R Soc Open Sci ; 10(7): 230452, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37476509

RESUMO

Knowledge of baleen whales' reproductive physiology is limited and requires long-term individual-based studies and innovative tools. We used 6 years of individual-level data on the Pacific Coast Feeding Group gray whales to evaluate the utility of faecal progesterone immunoassays and drone-based photogrammetry for pregnancy diagnosis. We explored the variability in faecal progesterone metabolites and body morphology relative to observed reproductive status and estimated the pregnancy probability for mature females of unknown reproductive status using normal mixture models. Individual females had higher faecal progesterone concentrations when pregnant than when presumed non-pregnant. Yet, at the population level, high overlap and variability in progesterone metabolite concentrations occurred between pregnant and non-pregnant groups, limiting this metric for accurate pregnancy diagnosis in gray whales. Alternatively, body width at 50% of the total body length (W50) correctly discriminated pregnant from non-pregnant females at individual and population levels, with high accuracy. Application of the model using W50 metric to mature females of unknown pregnancy status identified eight additional pregnancies with high confidence. Our findings highlight the utility of drone-based photogrammetry to non-invasively diagnose pregnancy in this group of gray whales, and the potential for improved data on reproductive rates for population management of baleen whales generally.

3.
Med Oral Patol Oral Cir Bucal ; 24(3): e346-e353, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31011146

RESUMO

BACKGROUND: The present study attempted to provide information regarding non-muscle myosin II (MII) isoforms immunoreactivity in patients with head and neck squamous cell carcinoma (HNSCC) and analysis of the patients' clinical status after 5 years of monitoring. MATERIAL AND METHODS: A semiquantitative analysis of the immunoreactivity of the MII isoforms was performed in 54 surgical specimens and its correlation with clinical and pathological variables and prognosis was verified. Data were analyzed using chi-square, Mann-Whitney and Kruskal-Wallis tests. To evaluate the survival over the total monitoring time and any connection with the proteins studied, the Kaplan-Meier analysis was used. P values ≤0.05 were considered statistically significant. RESULTS: In the advanced stages of pathological tumor-node-metastasis, the expression of MIIB in adjacent non-neoplastic epithelial tissues tended to increase (p = 0.057). In tumoral zones there was an association of high expression among the three isoforms (MIIA/MIIB p=0,001, MIIB/MIIC p=0,006 and MIIA/MIIC p=0,012). Negative clinical evolution in patients was directly correlated to increased MIIC expression in the tumoral zone of invasion in HNSCC (p = 0.017). Based on clinical evolution after the monitoring period, patients with tumors expressing MIIC had poorer prognoses (p = 0.048). CONCLUSIONS: The present study suggests that MIIB expression in non-neoplastic adjacent epithelial tissues may indicate a potential for regional metastasis and that MIIC expression in the tumoral zone of invasion is predictive of negative evolution of the disease.


Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Carcinoma de Células Escamosas de Cabeça e Pescoço , Biomarcadores Tumorais , Humanos , Miosina Tipo II , Prognóstico
4.
Radiologe ; 53(1): 30-7, 2013 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-23338247

RESUMO

Cardiovascular magnetic resonance imaging (CMRI) has become the primary tool for the non-invasive assessment in patients with suspected myocarditis, especially after exclusion of acute coronary syndrome (ACS) for the differential diagnosis. Various MRI parameters are available which have different accuracies. Volumetric and functional ventricular assessment and the occurrence of pericardial effusion alone demonstrate only a poor sensitivity and specificity. The calculation of the T2-ratio (edema assessment), the early or global relative myocardial enhancement (gRE) and the late gadolinium enhancement (LGE), which represents irreversibly injured myocardium, are more specific parameters. All MRI parameters demonstrate the best accuracy in infarct-like acute myocarditis, whereas in chronic myocarditis sensitivity and specificity are less accurate. Therefore, a multisequential (at least two out of three parameters are positive) approach is recommended. The assessment of the value of newer, more quantitative MRI sequences, such as T1 and T2-mapping is still under investigation.


Assuntos
Aumento da Imagem/métodos , Imagem Cinética por Ressonância Magnética/métodos , Miocardite/diagnóstico , Volume Sistólico , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
5.
J Breath Res ; 5(4): 046006, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21908906

RESUMO

This experiment observed the evolution of metabolite plumes from a human trapped in a simulation of a collapsed building. Ten participants took it in turns over five days to lie in a simulation of a collapsed building and eight of them completed the 6 h protocol while their breath, sweat and skin metabolites were passed through a simulation of a collapsed glass-clad reinforced-concrete building. Safety, welfare and environmental parameters were monitored continuously, and active adsorbent sampling for thermal desorption GC-MS, on-line and embedded CO, CO(2) and O(2) monitoring, aspirating ion mobility spectrometry with integrated semiconductor gas sensors, direct injection GC-ion mobility spectrometry, active sampling thermal desorption GC-differential mobility spectrometry and a prototype remote early detection system for survivor location were used to monitor the evolution of the metabolite plumes that were generated. Oxygen levels within the void simulator were allowed to fall no lower than 19.1% (v). Concurrent levels of carbon dioxide built up to an average level of 1.6% (v) in the breathing zone of the participants. Temperature, humidity, carbon dioxide levels and the physiological measurements were consistent with a reproducible methodology that enabled the metabolite plumes to be sampled and characterized from the different parts of the experiment. Welfare and safety data were satisfactory with pulse rates, blood pressures and oxygenation, all within levels consistent with healthy adults. Up to 12 in-test welfare assessments per participant and a six-week follow-up Stanford Acute Stress Response Questionnaire indicated that the researchers and participants did not experience any adverse effects from their involvement in the study. Preliminary observations confirmed that CO(2), NH(3) and acetone were effective markers for trapped humans, although interactions with water absorbed in building debris needed further study. An unexpected observation from the NH(3) channel was the suppression of NH(3) during those periods when the participants slept, and this will be the subject of further study, as will be the detailed analysis of the casualty detection data obtained from the seven instruments used.


Assuntos
Ar/análise , Dióxido de Carbono/análise , Desastres , Exposição Ambiental/análise , Expiração/fisiologia , Modelos Teóricos , Monitorização Fisiológica/métodos , Adulto , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Masculino , Pessoa de Meia-Idade , Oxigênio/análise , Adulto Jovem
6.
Environ Monit Assess ; 113(1-3): 367-83, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16520873

RESUMO

The Atlantic Coastal Action Program (ACAP) is a unique, community-based program initiated by Environment Canada in 1991 to help Atlantic Canadians restore and sustain watersheds and adjacent coastal areas. ACAP is the eastem-most Environment Canada Ecosystem Initiative. The ACAP family is currently made up of 14 ecosystem-based organizations in the four Atlantic provinces. Each one of these non-profit organizations operates independently, but is formally linked under the umbrella of ACAP to represent a force stronger than the individual parts. In Environment Canada's experience, the program consistently demonstrates the value of a community-based approach and produces results on an ecosystem basis. This paper will examine some of the impacts of ACAP in terms of economics, credible community science, and environmental results which most often align with Environment Canada's objectives. It will explore the influences of the community-based approach to environmental management on multiple scales (local, regional, etc.). Through examples, the paper will demonstrate the effectiveness of ACAP in influencing some of the policies, programs and attitudes of various levels of government and industry in the region, as well as describe how the community-based model has been exported internationally. The paper will conclude with a discussion on a planned path forward for ACAP.


Assuntos
Redes Comunitárias , Conservação dos Recursos Naturais , Monitoramento Ambiental/métodos , Desenvolvimento de Programas , Poluição da Água/prevenção & controle , Oceano Atlântico , Canadá , Conservação dos Recursos Naturais/legislação & jurisprudência , Conservação dos Recursos Naturais/métodos , Conservação dos Recursos Naturais/tendências
7.
Ophthalmology ; 107(5): 837-43, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10811071

RESUMO

OBJECTIVE: The purpose of this study is to provide a review of the ocular injuries sustained by survivors of the April 19, 1995, bombing of the Alfred P. Murrah Federal Building in Oklahoma City. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: The authors retrospectively evaluated data collected on all surviving persons receiving ocular injuries during the bombing and on all at-risk occupants of the federal building and four adjacent buildings. METHODS: Injury data from survivors were collected from multiple sources to include hospital medical records, a physician survey, emergency medical services run reports, written survivor accounts, building occupant survey, telephone interviews, and mail surveys. MAIN OUTCOME MEASURES: The types of ocular injuries, the associated systemic injuries, and the location of the injured at the time of the blast were evaluated. RESULTS: Fifty-five (8%) of the 684 injured bombing survivors sustained an ocular injury. Persons injured in the Murrah building were more than three times more likely to sustain an ocular injury than other injured persons. Seventy-one percent of ocular injuries occurred within 300 feet of the point of detonation. The most common serious ocular injuries included lid/brow lacerations (20 patients, 23 eyes), open globe injuries (12 eyes), orbital fractures (6 eyes), and retinal detachment (5 eyes). A retained intraocular foreign body accounted for only two of the injuries (4%). Glass accounted for nearly two thirds of the ocular injuries. CONCLUSIONS: Blasts involving explosions inflict severe ocular injury, mostly as a result of secondary blast effects from glass, debris, etc. Eye injuries in bombings can probably be prevented by increasing the distance from and orientation away from windows (i.e., by facing desks away from windows). Use of such products as laminated glass, toughened window glazing, and Mylar curtains may reduce glass projectiles in the blast vicinity.


Assuntos
Traumatismos por Explosões/patologia , Explosões , Corpos Estranhos no Olho/patologia , Ferimentos Oculares Penetrantes/patologia , Sobrancelhas/lesões , Pálpebras/lesões , Órbita/lesões , Adolescente , Adulto , Traumatismos por Explosões/epidemiologia , Traumatismos por Explosões/etiologia , Criança , Pré-Escolar , Vítimas de Crime , Corpos Estranhos no Olho/epidemiologia , Corpos Estranhos no Olho/etiologia , Ferimentos Oculares Penetrantes/epidemiologia , Ferimentos Oculares Penetrantes/etiologia , Feminino , Vidro , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Oklahoma/epidemiologia , Fraturas Orbitárias/epidemiologia , Fraturas Orbitárias/etiologia , Fraturas Orbitárias/patologia , Descolamento Retiniano/epidemiologia , Descolamento Retiniano/etiologia , Descolamento Retiniano/patologia , Estudos Retrospectivos , Sobreviventes
8.
J Biomed Mater Res ; 48(3): 251-7, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10398028

RESUMO

Uniaxial fatigue testing was performed on different diameters of fine wires made from MP35N. The fatigue limits of the wires differed from each other based on the diameter of the wire. Multiaxial (shear) fatigue testing was also performed on a benchmark coil used to evaluate the fatigue life of all modern pacemaker leads (the CENELEC standard coil). A computer algorithm was used to quantify the maximum shear stress and strain on the coil. The bend radius, coil diameter, wire diameter, and pitch of the coil all affect the shear stress and strain and therefore the fatigue properties of conductor coils. Based on the analysis presented, it was determined that the portion of the CENELEC standard dealing with fatigue, when used in its present format, is not a valid fatigue test for pacemaker leads.


Assuntos
Materiais Biocompatíveis , Chumbo , Marca-Passo Artificial , Humanos , Mecânica
9.
J Am Med Inform Assoc ; 6(1): 61-75, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-9925229

RESUMO

OBJECTIVE: To support clinically relevant indexing of biomedical images and image-related information based on the attributes of image acquisition procedures and the judgments (observations) expressed by observers in the process of image interpretation. DESIGN: The authors introduce the notion of "image acquisition context," the set of attributes that describe image acquisition procedures, and present a standards-based strategy for utilizing the attributes of image acquisition context as indexing and retrieval keys for digital image libraries. METHODS: The authors' indexing strategy is based on an interdependent message/terminology architecture that combines the Digital Imaging and Communication in Medicine (DICOM) standard, the SNOMED (Systematized Nomenclature of Human and Veterinary Medicine) vocabulary, and the SNOMED DICOM microglossary. The SNOMED DICOM microglossary provides context-dependent mapping of terminology to DICOM data elements. RESULTS: The capability of embedding standard coded descriptors in DICOM image headers and image-interpretation reports improves the potential for selective retrieval of image-related information. This favorably affects information management in digital libraries.


Assuntos
Indexação e Redação de Resumos , Diagnóstico por Imagem/classificação , Armazenamento e Recuperação da Informação , Vocabulário Controlado , Humanos , Interpretação de Imagem Assistida por Computador
10.
Opt Lett ; 24(22): 1573-4, 1999 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-18079867

RESUMO

We present a new concept for an electronically tunable diode laser. It is based on an external-cavity configuration with simultaneous feedback and intracavity spatial separation of the laser's spectral components. The electronical tunability is achieved by insertion of a liquid-crystal array as an electronically controlled aperture into the region of spatial separation of the spectral components. Wavelength tunability without mechanical movement over a range of 10 nm and two-color operation are demonstrated with a 670-nm laser diode.

11.
Artigo em Inglês | MEDLINE | ID: mdl-18255866

RESUMO

In this paper the applicability of evolution strategies, a special kind of evolutionary algorithms, to the problem of parameter optimization in the development of fuzzy rule-based systems is demonstrated. For this aim we introduce a shell which supports the design of any kind of rule based systems employing fuzzy logic for the formalization of imprecise reasoning processes and which optimizes all numerical parameters. This method works model-free, we do not need to know implicit features of the optimizing system.

12.
Neuropharmacology ; 34(12): 1597-606, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8788957

RESUMO

NMDA channel blockers are potentially advantageous therapeutic agents for the treatment of ischemia and head trauma, which greatly elevate extracellular glutamate, because they should most effectively inhibit high levels of receptor activation. A novel high affinity TCP site ligand, WIN 63480, does not produce MK-801- or PCP-like behavioral activation at anti-ischemic doses. While WIN 63480, MK-801 and PCP were all observed to be effective blockers of open NMDA channels, WIN 63480 had much less access to closed NMDA channels. This difference may be due to the fact that WIN 63480 is hydrophilic (logD = -4.1) while MK-801 and PCP are lipophilic (logD = +1.8). In vivo, closed channel access may result in a non-competitive profile of antagonism for MK-801 and PCP compared to a more uncompetitive profile for WIN 63480. Release of glutamate, and depolarization, are likely to produce a high level of NMDA receptor activation in ischemic areas compared to normal tissue. Consequently, at anti-ischemic doses, WIN 63480 may produce less inhibition of physiological NMDA-mediated processes in neural systems involved in behavioral regulation than MK-801 or PCP, leading to an improved side effect profile.


Assuntos
Córtex Cerebral/efeitos dos fármacos , Maleato de Dizocilpina/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Fenciclidina/farmacologia , Quinolizinas/farmacologia , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Animais , Sítios de Ligação/efeitos dos fármacos , Células Cultivadas , Córtex Cerebral/metabolismo , Relação Dose-Resposta a Droga , Ácido Cinurênico/análogos & derivados , Ácido Cinurênico/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Camundongos , Fenciclidina/análogos & derivados , Transfecção , Xenopus laevis
13.
Neuropharmacology ; 33(1): 109-14, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8183434

RESUMO

Algogens such as capsaicin, bradykinin, acetylcholine, 5-hydroxytryptamine and potassium ions applied to exposed tail skin of the rat isolated spinal cord-tail preparation evoke a ventral root response consisting of depolarization and spiking activity. L-glutamate and kainate also evoke similar reflexes. All these compounds evoke depolarization of afferent axons or dorsal root ganglion cells. Since GABA depolarizes unmyelinated afferent fibers, the ability of GABA receptor agonists to activate cutaneous nociceptive afferents has been examined. GABA superfused over exposed tail skin evoked a ventral root reflex essentially identical to that produced by capsaicin (3 microM). The EC50 was 27 microM. Muscimol, 3-aminopropane sulphonate, isoguvacine and beta-alanine had effects comparable to GABA, with EC50 values of 9.6, 26, 56 and 870 microM respectively. Baclofen (100 microM) or glycine (10 mM) had no effect. Bicuculline applied to the tail competitively antagonized GABA (Schild slope = -1.03) with a pA2 of 5.8. Spinal application of 1 microM morphine blocked the actions of GABA and capsaicin. These data indicate that GABAA receptors can depolarize and excite nociceptive afferents. GABA could be involved in nociception by contributing to firing of C-fibres, or by analogy to presynaptic inhibition in the spinal cord, may act to decrease neuropeptide transmitter release in cutaneous tissue.


Assuntos
Neurônios Aferentes/fisiologia , Nociceptores/fisiologia , Receptores de GABA-A/fisiologia , Medula Espinal/fisiologia , Cauda/fisiologia , Animais , Animais Recém-Nascidos/fisiologia , Axônios/efeitos dos fármacos , Axônios/fisiologia , Capsaicina/farmacologia , Eletrodos , Antagonistas GABAérgicos , Gânglios Espinais/citologia , Gânglios Espinais/efeitos dos fármacos , Técnicas In Vitro , Neurônios Aferentes/efeitos dos fármacos , Nociceptores/efeitos dos fármacos , Ratos , Receptores de Aminoácido/antagonistas & inibidores , Receptores de Aminoácido/efeitos dos fármacos , Receptores de GABA-A/efeitos dos fármacos , Medula Espinal/efeitos dos fármacos , Cauda/efeitos dos fármacos , Ácido gama-Aminobutírico/farmacologia
14.
J Pharmacol Exp Ther ; 265(2): 927-32, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-7684448

RESUMO

The rat isolated spinal cord-tail preparation was used to examine the ability of peripherally applied excitatory amino acids to stimulate ventral root reflexes. Bolus applications (3 sec) of domoate (0.1-10 microM) or kainate (KA; 10-300 microM) to exposed skin of the rat tail stimulated ventral root responses comparably to those evoked by capsaicin (0.3-10 microM) or bradykinin (0.1-10 microM). The ventral root potential evoked by both capsaicin and KA is thought to be a nociceptive response because both compounds selectively activate peripheral C-fibers. L-Glutamate (0.01-10 mM), quisqualate (0.1-1 mM) and amino-5-methyl-4-isoxazole-propionic acid (0.1-1.0 mM) were of lower potency than KA, whereas N-methyl-D-aspartate (1 mM) and L-aspartate (10 mM) were inactive. Responses evoked by prolonged application of KA faded rapidly. Capsaicin-evoked responses partially faded during prolonged application, but residual spiking activity was recorded for at least 30 min. KA did not evoke any observable response during application of capsaicin. The effects of KA and capsaicin were blocked by spinal application of morphine (0.3-1.0 microM) in a naloxone-reversible manner, consistent with activation of peripheral nociceptive afferents. The action of KA, but not capsaicin, was competitively inhibited by the amino-5-methyl-4-isoxazole-propionic acid/KA receptor antagonist 6,7-dinitroquinoxaline-2,3-dione (10-100 microM) applied to the rat tail (pA2 = 5.9). Conversely, ruthenium red (1 microM) selectively blocked capsaicin-evoked nociceptive reflexes. The existence of functional KA receptors on nociceptive afferents suggests that peripherally released glutamate or other excitatory amino acids could be involved in nociception or neurogenic inflammation.


Assuntos
Ácido Caínico/farmacologia , Nociceptores/fisiologia , Receptores de Glutamato/fisiologia , Aminoácidos/farmacologia , Animais , Potenciais Evocados , Antagonistas de Aminoácidos Excitatórios , Técnicas In Vitro , Morfina/farmacologia , Neurônios Aferentes/efeitos dos fármacos , Neurônios Aferentes/fisiologia , Nociceptores/efeitos dos fármacos , Quinoxalinas/farmacologia , Ratos , Receptores de Glutamato/efeitos dos fármacos , Receptores de Ácido Caínico , Reflexo/efeitos dos fármacos , Rutênio Vermelho/farmacologia , Medula Espinal/efeitos dos fármacos , Medula Espinal/fisiologia
15.
Agents Actions ; 39 Spec No: C142-4, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-7903836

RESUMO

The chemosensitivity of nociceptive afferents has been investigated using the isolated spinal-cord-tail preparation of the neonatal rat. L-glutamate applied to exposed rat tail skin stimulated nociceptive reflexes (ED50 = 136 microM). The action of L-glutamate was selective, since other constitutive L-amino acids or D-glutamate were inactive at a concentration of 10 mM. The known algogens bradykinin, acetylcholine, serotonin and potassium ions also stimulated nociceptive reflexes. Histamine (1 mM) and substance P (0.1 mM) had no observable effect. L-glutamate, which is released from macrophages, could therefore contribute to inflammation-related nociception by stimulation of cutaneous nociceptive nerve endings.


Assuntos
Glutamatos/farmacologia , Neurônios Motores/efeitos dos fármacos , Neurônios Aferentes/efeitos dos fármacos , Nociceptores/efeitos dos fármacos , Acetilcolina/farmacologia , Animais , Animais Recém-Nascidos , Bradicinina/farmacologia , Capsaicina/farmacologia , Ácido Glutâmico , Neurônios Motores/fisiologia , Nociceptores/fisiologia , Potássio/farmacologia , Ratos , Serotonina/farmacologia , Medula Espinal/efeitos dos fármacos , Cauda
16.
Eur J Pharmacol ; 203(3): 329-35, 1991 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-1663452

RESUMO

The existence of sigma receptors in the mouse, rat and guinea pig vasa deferentia has previously been proposed, although drug effects are inconsistent and generally occur only at high concentrations. The purpose of the present study was to evaluate lower, physiologically relevant concentrations of ligands for possible sigma effects on electrically stimulated twitch contractions in the mouse vas deferens (MVD). Putative sigma agonists and antagonists all inhibited 0.1 Hz electrically stimulated twitch contractions in nM concentrations. Inhibitory activity plateaued between 20 and 60% for all compounds except 1,3-di(2-tolyl)guanidine (DTG), which had a shallow concentration-effect curve. Subsequent to the plateau, higher concentrations (30 microM) of rimcazole and haloperidol fully inhibited electrically stimulated twitch contractions. There was no correlation between inhibitory potency or maximal effect in the MVD and binding potency at sigma sites in either MVD or guinea pig brain. The inhibitory effects of R(+)-3-(3-hydroxyphenyl)-N-1-propylpiperidine ((+)3-PPP) or DTG on electrically stimulated twitch contractions were not antagonized by the putative sigma antagonists DTG, haloperidol, rimcazole or BMY-14802, nor by alpha 2-adrenoceptor, dopamine D1, dopamine D2 or opiate antagonists. Although the mechanism of sigma ligand effects in the MVD has not been established, the data caution against a presumption that effects of sigma ligands on electrically stimulated twitch contractions in this preparation are mediated by sigma receptors.


Assuntos
Músculo Liso/efeitos dos fármacos , Receptores Opioides/metabolismo , Animais , Ligação Competitiva/efeitos dos fármacos , Química Encefálica/efeitos dos fármacos , Estimulação Elétrica , Guanidinas , Cobaias , Técnicas In Vitro , Masculino , Metoxamina/farmacologia , Camundongos , Contração Muscular/efeitos dos fármacos , Antagonistas de Entorpecentes , Ensaio Radioligante , Receptores Opioides/efeitos dos fármacos , Receptores sigma , Ducto Deferente/efeitos dos fármacos
17.
IMJ Ill Med J ; 172(5): 386, 1987 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-2891668
18.
Arch Environ Contam Toxicol ; 11(1): 93-8, 1982.
Artigo em Inglês | MEDLINE | ID: mdl-7073321

RESUMO

This paper reports the effects of Roundup herbicide (MON 02139) on rainbow trout viability and behavior in several field experiments at the University of British Columbia Research Forest. Laboratory and field 96-hr LC50 values were similar: 54.8 and 52.0 mg/L. Avoidance-preference data indicated that fish would avoid lethal levels of Roundup. Operational application of Roundup at the recommended field dose of (2.2 kg a.e./ha), as well as 10x and 100x field dose resulted in no mortality to rainbow trout in field streams. Results indicate that operational spraying with this herbicide for weed control should not be detrimental to rainbow trout populations. Improper use or accidental spills of Roundup could be avoided by rainbow trout and should not be lethal if diluted in a moderately-flowing stream.


Assuntos
Glicina/análogos & derivados , Herbicidas/toxicidade , Salmonidae , Truta , Animais , Glicina/toxicidade , Poluentes Químicos da Água/toxicidade , Glifosato
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...