Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
1.
NJ; BJOG: Int J Obstet Gy; July, 2022. 10 p. tab. (PCI-277).
Não convencional em Inglês | REPincaP, LIGCSA | ID: biblio-1400934

RESUMO

Objective: To assess, on a population basis, the medical care for pregnant women in specific geographic regions of six countries before and during the first year of the coronavirus disease 2019 (COVID-19) pandemic in relationship to pregnancy outcom. Results: Across all sites, a small but statistically significant increase in home births occurred between the pre-COVID-19 and COVID-19 periods (18.9% versus 20.3%, adjusted relative risk [aRR] 1.12, 95% CI 1.05­1.19). A small but significant decrease in the mean number of antenatal care visits (from 4.1 to 4.0, p = <0.0001) was seen during the COVID-19 period. Of outcomes evaluated, overall, a small but significant decrease in low-birthweight infants in the COVID-19 period occurred (15.7% versus 14.6%, aRR 0.94, 95% CI 0.89­0.99), but we did not observe any significant differences in other outcomes. There was no change observed in maternal mortality or antenatal haemorrhage overall or at any of the sites. Conclusions: Small but significant increases in home births and decreases in the antenatal care services were observed during the initial COVID-19 period; however, there was not an increase in the stillbirth, neonatal mortality, maternal mortality, low birthweight, or preterm birth rates during the COVID-19 period compared with the previous year. Further research should help to elucidate the relationship between access to and use of pregnancy-related medical services and birth outcomes over an extended period


Assuntos
Cuidados Médicos , Gestantes , Pandemias , Estudo Observacional , COVID-19
2.
BJOG ; 128(9): 1487-1496, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33629490

RESUMO

OBJECTIVE: Limited data are available from low- and middle-income countries (LMICs) on the relationship of haemoglobin levels to adverse outcomes at different times during pregnancy. We evaluated the association of haemoglobin levels in nulliparous women at two times in pregnancy with pregnancy outcomes. DESIGN: ASPIRIN Trial data were used to study the association between haemoglobin levels measured at 6+0 -13+6  weeks and 26+0 -30+0  weeks of gestation with fetal and neonatal outcomes. SETTING: Obstetric care facilities in Pakistan, India, Kenya, Zambia, The Democratic Republic of the Congo and Guatemala. POPULATION: A total of 11 976 pregnant women. METHODS: Generalised linear models were used to obtain adjusted relative risks and 95% CI for adverse outcomes. MAIN OUTCOME MEASURES: Preterm birth, stillbirth, neonatal death, small for gestational age (SGA) and birthweight <2500 g. RESULTS: The mean haemoglobin levels at 6+0 -13+6  weeks and at 26-30 weeks of gestation were 116 g/l (SD 17) and 107 g/l (SD 15), respectively. In general, pregnancy outcomes were better with increasing haemoglobin. At 6+0 -13+6  weeks of gestation, stillbirth, SGA and birthweight <2500 g, were significantly associated with haemoglobin of 70-89 g/l compared with haemoglobin of 110-129 g/l The relationships of adverse pregnancy outcomes with various haemoglobin levels were more marked at 26-30 weeks of gestation. CONCLUSIONS: Both lower and some higher haemoglobin concentrations are associated with adverse fetal and neonatal outcomes at 6+0 -13+6  weeks and at 26-30 weeks of gestation, although the relationship with low haemoglobin levels appears more consistent and generally stronger. TWEETABLE ABSTRACT: Both lower and some higher haemoglobin concentrations were associated with adverse fetal and neonatal outcomes at 6-13 weeks and 26-30 weeks of gestation.


Assuntos
Hemoglobinas/análise , Recém-Nascido Pequeno para a Idade Gestacional , Morte Perinatal , Nascimento Prematuro/epidemiologia , Natimorto/epidemiologia , Adulto , Países em Desenvolvimento , Índices de Eritrócitos , Feminino , Idade Gestacional , Humanos , Gravidez , Primeiro Trimestre da Gravidez , Fatores de Risco
3.
Brain Inj ; 33(13-14): 1602-1614, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31476880

RESUMO

Background: Research has shown that number of and blast-related Traumatic Brain Injuries (TBI) are associated with higher levels of service-connected disability (SCD) among US veterans. This study builds and tests a prediction model of SCD based on combat and training exposures experienced during active military service.Methods: Based on 492 US service member and veteran data collected at four Department of Veterans Affairs (VA) sites, traditional and Machine Learning algorithms were used to identify a best set of predictors and model type for predicting %SCD ≥50, the cut-point that allows for veteran access to 0% co-pay for VA health-care services.Results: The final model of predicting %SCD ≥50 in veterans revealed that the best blast/injury exposure-related predictors while deployed or non-deployed were: 1) number of controlled detonations experienced, 2) total number of blast exposures (including controlled and uncontrolled), and 3) the total number of uncontrolled blast and impact exposures.Conclusions and Relevance: We found that the highest blast/injury exposure predictor of %SCD ≥50 was number of controlled detonations, followed by total blasts, controlled or uncontrolled, and occurring in deployment or non-deployment settings. Further research confirming repetitive controlled blast exposure as a mechanism of chronic brain insult should be considered.


Assuntos
Lesões Encefálicas Traumáticas/epidemiologia , Distúrbios de Guerra/epidemiologia , Pessoas com Deficiência , Militares , United States Department of Veterans Affairs/tendências , Veteranos , Adulto , Idoso , Traumatismos por Explosões/diagnóstico , Traumatismos por Explosões/epidemiologia , Traumatismos por Explosões/psicologia , Lesões Encefálicas Traumáticas/diagnóstico , Lesões Encefálicas Traumáticas/psicologia , Estudos de Coortes , Distúrbios de Guerra/diagnóstico , Distúrbios de Guerra/psicologia , Pessoas com Deficiência/psicologia , Feminino , Previsões , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Militares/psicologia , Modelos Teóricos , Estados Unidos/epidemiologia , Veteranos/psicologia , Adulto Jovem
4.
Equine Vet J ; 51(3): 375-383, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30218449

RESUMO

BACKGROUND: Early and accurate detection of stress remodelling in racehorses is of utmost importance to prevent catastrophic injuries. Current imaging techniques have limitations in assessing early changes predisposing to catastrophic breakdowns. Positron emission tomography (PET) using 18 F-sodium fluoride (18 F-NaF) is a sensitive method for the detection of early bone turnover and may improve early recognition of subtle injuries. OBJECTIVES: To validate the clinical use of 18 F-NaF PET in Thoroughbred racehorses, to assess the value of PET in the detection of bone lesions and to compare PET results with findings of other advanced imaging modalities, clinical examination and pathology. STUDY DESIGN: Experimental exploratory study. METHODS: Twenty fetlocks from nine Thoroughbred racehorses were imaged using 18 F-NaF PET, computed tomography (CT) and scintigraphy. Five fetlocks were also imaged with magnetic resonance imaging and four fetlocks were also examined histologically. Imaging findings were independently reviewed by three board certified radiologists. Imaging, clinical and histopathological findings were correlated. RESULTS: PET imaging was well-tolerated by all horses. PET detected focal areas of 18 F-NaF uptake in instances where other imaging modalities did not identify abnormalities, in particular in the proximal sesamoid bones. Maximal standardised uptake values could be measured to quantify the activity of lesions. Areas of 18 F-NaF uptake corresponded to regions of increased vascularity and increased osteoblastic activity. MAIN LIMITATIONS: Limited number of cases. CONCLUSIONS: 18 F-NaF PET imaging of the Thoroughbred fetlock is feasible and compares favourably with other imaging modalities in detecting stress remodelling in Thoroughbred racehorses. PET appears to be a beneficial imaging modality when used for early detection of stress remodelling in an effort to prevent catastrophic musculoskeletal injuries in this population of horses.


Assuntos
Cavalos , Articulações/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/veterinária , Compostos Radiofarmacêuticos/farmacologia , Fluoreto de Sódio/farmacologia , Animais , Membro Anterior , Membro Posterior , Coxeadura Animal/diagnóstico , Imageamento por Ressonância Magnética , Cintilografia , Tomografia Computadorizada por Raios X
5.
Brain Inj ; 32(10): 1169-1177, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29883191

RESUMO

PRIMARY OBJECTIVES: To describe the association between mild traumatic brain injury (mTBI) and pain intensity and pain interference outcomes while accounting for potential confounders and mediators including environmental factors and comorbidities in a cohort of US Veterans of the Iraq and Afghanistan wars. RESEARCH DESIGN: Cross-sectional snapshot of baseline data from a prospective, longitudinal study. METHODS: Effects of mTBI on pain intensity and pain interference were compared between participants with or without mTBI exposure. Data were analysed using covariate-adjusted regression analyses as well as structural equation modelling (SEM) methods to assess the robustness of findings across different modelling assumptions. As results of the two approaches were consistent with respect to the overall association between mTBI exposure and pain, the results focus primarily on the SEM findings. RESULTS: The mTBI exposed group reported significantly greater indices of post-traumatic stress disorder (PTSD), depression, anxiety and sleep disturbance. After accounting for other factors, mTBI exposure was significantly, but indirectly associated with the pain interference and pain intensity outcomes. CONCLUSIONS: mTBI is strongly associated with pain intensity and pain interference in this sample. However, the effect appears to be mediated by other common mTBI comorbidities: PTSD, depression, anxiety and sleep disturbance.


Assuntos
Lesão Encefálica Crônica/complicações , Lesão Encefálica Crônica/epidemiologia , Dor Crônica/epidemiologia , Dor Crônica/etiologia , Militares , Síndrome Pós-Concussão/epidemiologia , Adulto , Idoso , Estudos de Coortes , Estudos Transversais , Feminino , Humanos , Guerra do Iraque 2003-2011 , Masculino , Pessoa de Meia-Idade , Transtornos do Humor/epidemiologia , Transtornos do Humor/etiologia , Avaliação de Resultados em Cuidados de Saúde , Medição da Dor , Transtornos do Sono-Vigília/etiologia , Estados Unidos/epidemiologia , Adulto Jovem
6.
Brain Inj ; 30(12): 1469-1480, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27834538

RESUMO

PRIMARY OBJECTIVES: To establish and comprehensively evaluate a large cohort of US veterans who served in recent military conflicts in order to better understand possible chronic and late-life effects of mild traumatic brain injury (mTBI), including those that may stem from neurodegeneration. RESEARCH DESIGN: Cross-sectional and prospective longitudinal. METHODS AND PROCEDURES: Inclusion criteria are prior combat exposure and deployment(s) in Operation Enduring Freedom, Operation Iraqi Freedom or one of their follow-on conflicts (collectively OEF/OIF). Effects of mTBI will be assessed by enrolling participants across the entire spectrum of mTBI, from entirely negative to many mTBIs. Longitudinal assessments consist of in-person comprehensive testing at least every 5 years, with interval annual telephonic testing. The primary outcome is the composite score on the NIH Toolbox neuropsychological test battery. Assessments also include structured interviews, questionnaires, traditional neuropsychological testing, motor, sensory and vestibular functions, neuroimaging, electrophysiology, genotypes and biomarkers. MAIN OUTCOMES AND RESULTS: The authors fully describe the study methods and measures and report demographic and exposure characteristics from the early portion of the cohort of OEF/OIF veterans. CONCLUSIONS: This centrepiece observational study of the Chronic Effects of Neurotrauma Consortium (CENC) is successfully launched and, within several years, should provide fertile data to begin investigating its aims.


Assuntos
Concussão Encefálica/complicações , Concussão Encefálica/epidemiologia , Transtornos Cognitivos/etiologia , Transtornos da Motilidade Ocular/etiologia , Adulto , Campanha Afegã de 2001- , Concussão Encefálica/diagnóstico , Estudos de Coortes , Estudos Transversais , Eletroencefalografia , Feminino , Humanos , Guerra do Iraque 2003-2011 , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Autorrelato , Estados Unidos , Veteranos , Adulto Jovem
7.
Vet Comp Orthop Traumatol ; 26(5): 356-65, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23800744

RESUMO

Elbow dysplasia, primarily affecting the medial compartment, is the most common cause of lameness in the thoracic limb. Elbow arthroplasty is an option for end stage or severely affected patients. The purpose of this study was to compare ex vivo axial load to failure of an implanted novel elbow arthroplasty system to control limbs. The partial arthroplasty is a medial compartmental, unconstrained system, intended to allow conversion to total arthroplasty. We hypothesized that there would not be any significant difference between implanted and controlled limbs when loaded to failure. Six pairs of medium mixed breed canine cadaveric thoracic limbs were prepared for comparison of failure loading of control and implanted limbs. Axial compression was performed using a mechanical testing system. Failure loads were normalized to bodyweight. The mean normalized failure load (N/kg) for the implanted limbs and control limbs were 2.47 (range: 1.62-3.38) and 2.68 (range: 2.25-3.25), respectively. An implanted to control ratio of 0.93 ± 0.19 was calculated. The difference between paired control and implanted limbs in normalized failure loading was not significant (p = 0.38). There were not any differences noted in the yield load (p = 0.30), stiffness (p = 0.62), or energy (0.58). Failure modes were recorded. We concluded that the differences between implanted and control limbs in supra-physiologic axial load to failure were not significant.


Assuntos
Artroplastia/veterinária , Cães/fisiologia , Membro Anterior/fisiologia , Articulações/fisiologia , Teste de Materiais , Próteses e Implantes/veterinária , Animais , Artroplastia/instrumentação , Artroplastia/métodos , Fenômenos Biomecânicos , Cadáver , Análise de Falha de Equipamento , Desenho de Prótese , Estresse Mecânico
8.
Mucosal Immunol ; 6(4): 692-703, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23299618

RESUMO

Prevention of HIV-1 transmission at mucosal surfaces will likely require durable pre-existing mucosal anti-HIV-1 antibodies (Abs). Defining the ontogeny, specificities and potentially protective nature of the initial mucosal virus-specific B-cell response will be critical for understanding how to induce protective Ab responses by vaccination. Genital fluids from patients within the earliest stages of acute HIV-1 infection (Fiebig I-VI) were examined for multiple anti-HIV specificities. Gp41 (but not gp120) Env immunoglobulin (Ig)A Abs were frequently elicited in both plasma and mucosal fluids within the first weeks of transmission. However, shortly after induction, these initial mucosal gp41 Env IgA Abs rapidly declined with a t(½) of ∼2.7 days. B-cell-activating factor belonging to the TNF family (BAFF) was elevated immediately preceding the appearance of gp41 Abs, likely contributing to an initial T-independent Ab response. HIV-1 transmission frequently elicits mucosal HIV-1 envelope-specific IgA responses targeted to gp41 that have a short half-life.


Assuntos
Proteína gp41 do Envelope de HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Imunoglobulina A/imunologia , Especificidade de Anticorpos/imunologia , Fator Ativador de Células B/metabolismo , Linfócitos B/imunologia , Linfócitos B/metabolismo , Feminino , Infecções por HIV/metabolismo , Infecções por HIV/transmissão , Humanos , Imunidade nas Mucosas , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Ativação Linfocitária/imunologia , Masculino , Fatores de Tempo
9.
Int J STD AIDS ; 22(11): 665-70, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22096053

RESUMO

The aim of this study was to identify baseline prognostic factors for poor clinical outcome of HIV-associated cryptococcal meningitis. We conducted a trial in Thailand and the USA comparing low- and high-dose concomitant use of amphotericin B and fluconazole for HIV-associated cryptococcal meningitis to amphotericin B followed by fluconazole. Subjects who were either alive and cerebrospinal fluid (CSF) culture-positive or dead were considered to have a poor outcome. At day 14, baseline characteristics associated with poor outcome included: low weight, high CSF cryptococcal antigen (CrAg) titre and low CSF white blood cell (WBC) count. At day 70, the associated baseline characteristics included: CSF CrAg titre >1:1024 and low Karnofsky performance status. Overall, consistent with published findings, low weight, high CSF CrAg titre and low CSF WBC counts at baseline were predictors for poor clinical outcome. In addition, we found that low Karnofsky performance status was predictive of poor outcome. Prompt management with appropriate antifungal therapy for this particular group of patients may improve the outcomes.


Assuntos
Infecções por HIV/complicações , Meningite Criptocócica/diagnóstico , Meningite Criptocócica/patologia , Anfotericina B/administração & dosagem , Antifúngicos/administração & dosagem , Líquido Cefalorraquidiano/microbiologia , Fluconazol/administração & dosagem , Humanos , Meningite Criptocócica/tratamento farmacológico , Meningite Criptocócica/mortalidade , Prognóstico , Análise de Sobrevida , Tailândia , Resultado do Tratamento , Estados Unidos
10.
Vet Comp Orthop Traumatol ; 24(6): 435-44, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21938309

RESUMO

OBJECTIVES: To document the contributions of trial repetition, limb side, and intraday and inter-week measurements on variation in vertical and craniocaudal ground reaction force data. METHODS: Following habituation, force and time data were collected for all four limbs of seven Labrador Retrievers during sets of five valid trot trials. Each set was performed twice daily (morning and afternoon), every seven days for three consecutive weeks. A repeated measures analysis of variance was used to determine the effects of limb, trial, intraday, and inter-week factors on ground reaction force data for the thoracic and pelvic limbs. RESULTS: Of the four factors evaluated, variation due to trial repetition had the largest magnitude of effect on ground reaction forces. Trial within a set of data had an effect on all craniocaudal, but not vertical, ground reaction force variables studied, for the thoracic limbs. The first of five trials was often different from later trials. Some thoracic limb and pelvic limb variables were different between weeks. A limb side difference was only apparent for pelvic limb vertical ground reaction force data. Only pelvic limb craniocaudal braking variables were different between sets within a day. DISCUSSION AND CLINICAL SIGNIFICANCE: When controlling for speed, handler, gait, weight and dog breed, variation in ground reaction forces mainly arise from trial repetition and inter-week data collection. When using vertical peak force and impulse to evaluate treatment, trial repetition and inter-week data collection should have minimal effect of the data.


Assuntos
Marcha/fisiologia , Locomoção/fisiologia , Animais , Fenômenos Biomecânicos , Cães , Feminino , Masculino
11.
Contemp Clin Trials ; 31(1): 34-43, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19897055

RESUMO

BACKGROUND: International clinical trials can provide scientific and logistic benefits in spite of the many challenges. Determining whether a country, especially a developing country, is an appropriate location for the research should include in-country consultation and partnering to assess its social value for the population; that treatments are relevant for the population under study; and that the research infrastructure and ethical oversight are adequate. Collaboration increases the likelihood of study success and helps ensure that benefits accrue to recruited populations and their community. PURPOSE: This paper describes our experiences on a bi-national study and may provide guidance for those planning to engage in future collaborations. METHODS: A Thai and United States team collaborated to develop and implement a phase II clinical trial for HIV-associated cryptococcal meningitis to assess safety and tolerability of combination therapy vs. standard treatment. Clinical and cultural differences, regulatory hurdles and operational issues were addressed before and during the study to ensure a successful collaboration between the 2 groups. RESULTS: The international multicenter study allowed for more rapid enrollment, reduced costs to complete the study, sharing of the benefits of research, greater generalizability of results and capacity building in Thailand; quality metrics in Thailand were equivalent to or better than those in the U.S. CONCLUSIONS: Conducting successful clinical trials internationally requires early and ongoing collaboration to ensure the study meets sites' requirements and expectations, conforms to varying national regulations, adheres to data quality standards and is responsive to the health needs of studied populations.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Anfotericina B/administração & dosagem , Antifúngicos/administração & dosagem , Fluconazol/administração & dosagem , Cooperação Internacional , Meningite Criptocócica/tratamento farmacológico , Adulto , Anfotericina B/toxicidade , Antifúngicos/toxicidade , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Estudos de Viabilidade , Fluconazol/toxicidade , Humanos , Seleção de Pacientes , Projetos de Pesquisa , Tailândia , Estados Unidos
12.
HIV Med ; 11(4): 276-81, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20002501

RESUMO

OBJECTIVES: The aim of the present study was to assess fluconazole pharmacokinetic measures in serum and cerebrospinal fluid (CSF); and the correlation of these measures with clinical outcomes of invasive fungal infections. METHODS: A randomized trial was conducted in HIV-infected patients receiving three different regimens of fluconazole plus amphotericin B (AmB) for the treatment of cryptococcal meningitis. Regimens included fluconazole 400 mg/day+AmB (AmB+Fluc400) or fluconazole 800 mg/day+AmB (AmB+Fluc800) (14 days followed by fluconazole alone at the randomized dose for 56 days); or AmB alone for 14 days followed by fluconazole 400 mg/day for 56 days. Serum (at 24 h after dosing) and CSF samples were taken at baseline and days 14 and 70 (serum only) for fluconazole measurement, using gas-liquid chromatography. RESULTS: Sixty-four treated patients had fluconazole measurements: 11 in the AmB group, 12 in the AmB+Fluc400 group and 41 in the AmB+Fluc800 group. Day 14 serum concentration geometric means were 24.7 mg/L for AmB+Fluc400 and 37.0 mg/L for AmB+Fluc800. Correspondingly, CSF concentration geometric means were 25.1 mg/L and 32.7 mg/L. Day 14 Serum and CSF concentrations were highly correlated with AmB+Fluc800 (P<0.001, r=0.873) and AmB+Fluc400 (P=0.005, r=0.943). Increased serum area under the curve (AUC) appears to be associated with decreased mortality at day 70 (P=0.061, odds ratio=2.19) as well as with increased study composite endpoint success at days 42 and 70 (P=0.081, odds ratio=2.25 and 0.058, 2.89, respectively). CONCLUSION: High fluconazole dosage (800 mg/day) for the treatment of HIV-associated cryptococcal meningitis was associated with high serum and CSF fluconazole concentration. Overall, high serum and CSF concentration appear to be associated with increased survival and primary composite endpoint success.


Assuntos
Anfotericina B/farmacocinética , Antifúngicos/farmacocinética , Fluconazol/farmacocinética , Infecções por HIV/metabolismo , Meningite Criptocócica/metabolismo , Anfotericina B/sangue , Anfotericina B/líquido cefalorraquidiano , Fármacos Anti-HIV/uso terapêutico , Antifúngicos/sangue , Antifúngicos/líquido cefalorraquidiano , Terapia Antirretroviral de Alta Atividade , Disponibilidade Biológica , Cromatografia Gasosa , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Fluconazol/sangue , Fluconazol/líquido cefalorraquidiano , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Humanos , Meningite Criptocócica/tratamento farmacológico , Meningite Criptocócica/mortalidade , Modelos Biológicos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
13.
J Exp Biol ; 204(Pt 8): 1413-9, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11273803

RESUMO

The classic view of swimming control in scyphozoan and cubozoan jellyfish involves a diffuse motor nerve net activated by multiple pacemaker sites that interact in a simple resetting hierarchy. Earlier modeling studies of jellyfish swimming, utilizing resetting linkages of multiple pacemakers, indicated that increases in pacemaker number were correlated with increases in the rate and regularity of network activity. We conducted a similar study using the cubozoan jellyfish Carybdea marsupialis, concentrating not only on the adaptive features of multiple pacemaker networks but also on the mechanism of pacemaker interaction. The best fit for our experimental data is a model in which pacemakers express a degree of independence. Thus, our results challenge the idea that pacemaker interactions in scyphozoan and cubozoan medusae are based on a strict resetting hierarchy. Furthermore, our data suggest that the combination of semi-independent linkage of pacemakers with the small pacemaker number characteristic of cubomedusae is important in (i) maintaining a biphasic modulatory capability in the swimming system, and (ii) allowing behaviorally appropriate directional responses to asymmetrical sensory inputs in the radially arranged jellyfish nervous system.


Assuntos
Cifozoários/fisiologia , Animais , Relógios Biológicos/fisiologia , Eletrofisiologia , Modelos Biológicos , Natação/fisiologia
14.
J Exp Biol ; 204(Pt 7): 1257-68, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11249836

RESUMO

The seahare Aplysia spp. extracts many of its defensive chemicals from its red seaweed diet, including its purple ink, which is an effective deterrent against predators such as anemones and crabs. It is believed that the inking behavior is a high-threshold, all-or-none fixed act that nearly completely depletes the seahare of its ink supply. If a seahare depletes its gland of ink, it must seek out a source of red seaweed and then feed for at least 2 days to replenish its ink supply. This suggests that the animal would not be able to deploy ink more than once in rapid succession in response to successive attacks from one or more predators. However, we found that Aplysia spp. can secrete ink in response to three or more successive stimulations with (i) anemone tentacles, (ii) a mechanical stimulus, consisting of grabbing and lifting the animal from the substratum, or (iii) a noxious electric shock. A spectro-photometric measure of ink secretion showed that only approximately 48 % of the gland's releasable ink reserves are deployed initially. Thus, deployment of this defensive chemical is not strictly all-or-nothing, although the trigger mechanism is. Moreover, the animal tends to secrete a relatively fixed proportion (30--50 %) of its available ink reserves even after its gland has been depleted to approximately half its initial content. Since an animal need only use a proportion of its ink reserves to deter an attacker effectively, the inking behavior is adaptive in its economical use of a limited resource.


Assuntos
Aplysia/fisiologia , Comportamento Animal/fisiologia , Pigmentos Biológicos/metabolismo , Animais , Dieta , Estimulação Elétrica , Alga Marinha/química , Espectrofotometria
15.
J Exp Biol ; 201(Pt 10): 1595-613, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9556541

RESUMO

The marine snail Aplysia californica obtains its defensive ink exclusively from a diet of red seaweed. It stores the pigment (phycoerythrobilin, the red algal photosynthetic pigment, r-phycoerythrin, minus its protein) in muscular ink-release vesicles within the ink gland. Snails fed a diet of green seaweed or romaine lettuce do not secrete ink and their ink-release vesicles are largely devoid of ink. Successive activation of individual ink-release vesicles by ink motor neurons causes them to secrete approximately 55 % of their remaining ink (similar to the percentage of ink reserves released from the intact gland). The peripheral activation of vesicles appears to be cholinergic: 70 % of isolated vesicles were induced to squeeze ink from their valved end by solutions of acetylcholine at concentrations of 0.5 mmol l-1 or below. Ultrastructural analysis commonly found three cell types in the ink gland. The RER cells, the most numerous, were characterized by an extensive rough endoplasmic reticulum with greatly distended cisternae. This cell type is probably the site for synthesis of the high molecular mass protein of secreted ink. The granulate cells, less common than RER cells, had nuclear and cell areas significantly larger than those of RER cells. In addition, granulate cells of red-algal-fed snails had 4-14 vacuoles that contained electron-dense material with staining characteristics similar to that of ink in mature ink-release vesicles. The granulate cell's plasma membrane was regularly modified into grated areas, which both localized and expanded the surface area for coated vesicle formation and provided a sieve structure that prevented large particles in the hemolymph either from being taken up by, or from occluding, the coated vesicles. Electron-dense particles within coated vesicles were similar in size to those in granulate vacuoles but larger (on average by approximately 1 nm) than those that make up the ink. In green-seaweed-fed snails, granulate cells and their vacuoles were present but the vacuoles were empty. The third cell type, the vesicle cell, expands markedly, with its nucleus enlarging concurrent with cell growth until it is on average 50 times larger in cross-sectional area than the nuclei of either RER or granulate cells; the cytoplasm eventually becomes filled with ink, which obscures the mitochondria, vacuoles and nucleus. Continued cell expansion ceases with the appearance of an encircling layer of muscle and 1-3 layers of cells of unknown origin, thereby becoming the ink-release vesicle itself. The absorption spectra of the soluble contents of mature ink-release vesicles from snails fed red algae had peaks characteristic of the red algal pigment r-phycoerythrin or/and phycoerythrobilin. Immunogold localization of r-phycoerythrin showed no statistical difference in the amount of label within the ink-release vesicles, RER or granulate cell types. Furthermore, there was no localization of phycoerythrin immunoreactivity within the various cellular compartments of either the RER or granulate cells (nucleus, endoplasmic reticulum, mitochondria, vacuoles). Immunogold labeling in the ink gland ranged from 11 to 16 % of that for the digestive vacuoles of the rhodoplast digestive cells lining the tubules of the digestive gland. Our observations suggest (a) that the main form of the ink pigment in the gland is phycoerythrobilin or/and a non-antigenic form of phycoerythrin, and (b) that separation of the bilin from phycoerythrin (or its modification so that it is no longer antigenic) occurs before it reaches the ink gland, probably within the vacuoles of the rhodoplast digestive cells of the digestive gland. We propose the following model. The ink pigment, phycoerythrobilin, is cleaved from its protein in rhodoplast digestive vacuoles in the digestive gland. (ABSTRACT TRUNCATED)


Assuntos
Aplysia/metabolismo , Aplysia/fisiologia , Pigmentos Biológicos/biossíntese , Pigmentos Biológicos/metabolismo , Animais , Aplysia/ultraestrutura , Comportamento Animal , Glândulas Exócrinas/metabolismo , Glândulas Exócrinas/ultraestrutura , Imuno-Histoquímica , Microscopia Eletrônica , Ficoeritrina/metabolismo
16.
Clin Ther ; 19(1): 39-55; discussion 2-3, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9083707

RESUMO

Antihistamines are frequently part of the treatment regimen for seasonal and perennial allergic rhinitis occurring alone or in conjunction with associated airway disorders, such as asthma, sinusitis, and otitis media with effusion. These agents are also frequently prescribed for the treatment of urticaria to eliminate the need for long-term corticosteroids. This paper reviews the side-effect profile of the sedating and nonsedating agents (a classification given these drugs by the US Food and Drug Administration) in terms of patient satisfaction and quality-of-life parameters. Because the sedating antihistamines cross the blood-brain barrier more quickly and easily than the nonsedating antihistamines, they produce more central nervous system (CNS) effects, further exacerbating the decreases in decision-making, verbal learning, and psychomotor skills already experienced by the patient with allergic rhinitis. In contrast the now-preferred nonsedating agents do not readily cross the blood-brain barrier, do not produce CNS side effects, and, therefore, do not cause sedation or performance impairment. The nonsedating agents provide a safer alternative for patients with allergic rhinitis. Their use can increase patient satisfaction with the health care received.


Assuntos
Antagonistas dos Receptores Histamínicos H1/efeitos adversos , Hipnóticos e Sedativos/efeitos adversos , Rinite Alérgica Perene/tratamento farmacológico , Rinite Alérgica Sazonal/tratamento farmacológico , Cognição/efeitos dos fármacos , Tolerância a Medicamentos , Antagonistas dos Receptores Histamínicos H1/classificação , Antagonistas dos Receptores Histamínicos H1/farmacologia , Humanos , Hipnóticos e Sedativos/farmacologia , Aprendizagem/efeitos dos fármacos , Desempenho Psicomotor/efeitos dos fármacos , Qualidade de Vida
17.
J Neurosci ; 16(3): 1273-83, 1996 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-8558255

RESUMO

In this study we examined inputs to neurons in the medial subnucleus of the medial geniculate nucleus (mMG) for changes of synaptic efficacy associated with heart-rate conditioning to an auditory conditioned stimulus (CS). Conditioning-related changes of synaptic efficacy were measured in awake animals by examining mMG single-unit responses evoked by stimulation of one of two areas that send auditory CS and nonauditory information monosynaptically to the mMG, the brachium of the inferior colliculus (BlC) and the superior colliculus (SC). Synaptic efficacy was measured before, immediately after, and 1 hr after one session of classical conditioning with a tone CS and a corneal airpuff unconditioned stimulus. To determine whether conditioning produced changes of synaptic efficacy on the auditory BlC inputs to mMG cells and not general changes of cellular excitability, analyses of synaptic efficacy were performed on the mMG units that exhibited short-latency evoked responses (< 3.5 msec) to both BlC and SC stimulation. Analyses revealed that the BlC but not the SC test stimulus-evoked unit activity from the same neurons exhibited the following changes immediately after conditioning: decreases in unit response latency, increases in unit response reliability, and increases in spike frequency. BlC-evoked unit responses after pseudoconditioning did not exhibit these changes in unit responding. These results suggest that the synapses carrying auditory CS information to mMG neurons increase in strength as the result of associative conditioning with an acoustic CS. Some of these changes of synaptic efficacy remained 1 hr after training.


Assuntos
Vias Auditivas/fisiologia , Condicionamento Clássico/fisiologia , Corpos Geniculados/fisiologia , Sinapses/fisiologia , Estimulação Acústica , Animais , Feminino , Frequência Cardíaca/fisiologia , Masculino , Plasticidade Neuronal , Coelhos
18.
Arch Intern Med ; 155(5): 485-94, 1995 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-7864704

RESUMO

BACKGROUND: Three studies were undertaken to determine the minimum effective dosing regimen of ciprofloxacin for the treatment of acute, symptomatic, uncomplicated lower urinary tract infection. METHODS: All studies were multicenter, prospective, randomized, double-blind trials. A total of 970 evaluable patients with a diagnosis of urinary tract infection received oral ciprofloxacin (200 mg to 500 mg daily in one or two divided doses for 1, 3, 5, or 7 days) or norfloxacin (400 mg twice daily [BID] for 7 days). The primary measure of efficacy was bacteriologic eradication at the end of therapy. RESULTS: In study 1, bacteriologic eradication was reported in 95 (89%) and 101 (98%) of patients in the groups who received ciprofloxacin, 500-mg single dose and 250 mg BID for 7 days, respectively. Clinical success occurred in 101 patients (94%) who received a 500-mg single dose and in 103 patients (100%) who were administered 250 mg BID for 7 days. In study 2, eradication rates in the groups who received ciprofloxacin, 100 mg BID for 3 days, 250 mg BID for 3 days, and 250 mg BID for 7 days, were 98 (93%), 95 (90%), and 98 (93%), respectively. Clinical success was reported in 102 (97%), 105 (100%), and 104 (98%) of the patients, respectively. In study 3, the eradication rates in the groups who received ciprofloxacin in dosages of 500 mg once daily for 3 days and 500 mg once daily for 5 days and norfloxacin in a dosage of 400 mg BID for 7 days were 137 (92%), 134 (90%), and 133 (94%) of the women, respectively. Clinical success was the same (97%) in all three groups. Overall, short-course (either 3- or 5-day) therapy with ciprofloxacin was statistically equivalent to conventional (7-day) therapy with either ciprofloxacin or norfloxacin. Single-dose ciprofloxacin therapy was statistically less effective than conventional treatment. CONCLUSIONS: Ciprofloxacin at a dosage of 100 mg BID for 3 days was the minimum effective dose for the treatment of uncomplicated urinary tract infection in women.


Assuntos
Ciprofloxacina/uso terapêutico , Infecções Urinárias/tratamento farmacológico , Doença Aguda , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Ciprofloxacina/administração & dosagem , Ciprofloxacina/efeitos adversos , Contagem de Colônia Microbiana , Método Duplo-Cego , Esquema de Medicação , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Recidiva , Fatores de Risco , Resultado do Tratamento , Infecções Urinárias/microbiologia
19.
Eur J Clin Microbiol Infect Dis ; 13(10): 866-71, 1994 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7889961

RESUMO

Six multicenter clinical trials comparing cefprozil with cefaclor, amoxicillin-clavulanate or erythromycin in the management of skin and soft-tissue infections caused by susceptible bacteria demonstrate that cefprozil, given once or twice daily, is an effective chemotherapeutic agent in this context. Its pharmacokinetic behavior is compatible with once-daily or twice-daily administration, with a probability of improved patient compliance. Safety and tolerability compare favorably with other agents used in skin and soft-tissue infections.


Assuntos
Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Dermatopatias Bacterianas/tratamento farmacológico , Infecções dos Tecidos Moles/tratamento farmacológico , Adolescente , Adulto , Idoso , Amoxicilina/uso terapêutico , Combinação Amoxicilina e Clavulanato de Potássio , Cefaclor/uso terapêutico , Cefalosporinas/uso terapêutico , Criança , Pré-Escolar , Ácidos Clavulânicos/uso terapêutico , Ensaios Clínicos como Assunto , Quimioterapia Combinada/uso terapêutico , Eritromicina/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Multicêntricos como Assunto , Cefprozil
20.
Behav Neural Biol ; 61(3): 282-95, 1994 May.
Artigo em Inglês | MEDLINE | ID: mdl-8067983

RESUMO

Serotonin has been implicated in both nonassociative learning (sensitization and dishabituation) as well as associative learning (classical conditioning) in Aplysia californica. Dishabituation and sensitization, and their underlying physiological analogs, emerge according to different developmental timetables--sensitization develops 4 to 6 weeks after dishabituation (Rankin & Carew, 1988; Nolen & Carew, 1988; Wright, McCance, Lu, & Carew, 1991). Since the late emergence of sensitization could result from the delayed expression of facilitatory neurotransmitters, we have examined the ontogeny of serotonin immunoreactivity in juvenile A. californica by means of indirect immunohistofluorescence. The purpose of these experiments was to describe the developmental timetable for the expression of serotonin immunoreactivity and to correlate the emergence of immunoreactive neurons with the ontogenetic expression of different forms of learning. While the addition of serotonin-immunoreactive cells tracked the growth of the central nervous system, juveniles contained a relatively higher proportion of immunoreactive cells than adults. Immunoreactive cell bodies were present in the abdominal, cerebral, and pedal ganglia as early as juvenile Stage 9, prior to the emergence of dishabituation in Stage 10. The posterior cerebral cluster (PCC) contained four pairs of immunoreactive cells by Stage 9, including the facilitator CB1, which, as shown in adults, heterosynaptically facilitates siphon sensory neurons. The PCC reached the adult complement of five pairs of cells, by Stage 10, long before the development of sensitization, but at the time corresponding to the emergence of dishabituation. These results suggest that the late emergence of sensitization is not simply a consequence of the late expression of serotonergic facilitatory interneurons.


Assuntos
Aplysia/fisiologia , Aprendizagem/fisiologia , Neurônios/imunologia , Serotonina/imunologia , Animais , Sistema Nervoso Central/imunologia , Sistema Nervoso Central/fisiologia , Gânglios dos Invertebrados/imunologia , Fotomicrografia , Serotonina/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...