Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
1.
Toxicon ; 186: 78-82, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32771392

RESUMO

Envenomations during pregnancy have consequences affecting both maternal and fetal outcomes. U.S. poison center data on envenomations offers a comparative view of envenomations in pregnant and non-pregnant women. The National Poison Data System of the American Association of Poison Control Centers was searched for cases of envenomation during pregnancy between January 1, 2009 and December 31, 2018 and compared with exposures to non-pregnant females of childbearing age. Odds ratios and descriptive statistics were used where appropriate. There were a total of 3,555 venomous animal exposures in pregnant women during this 10-year period, most commonly with scorpion stings. These were compared with 87,553 envenomations in non-pregnant women of childbearing age during that time period. Overall, drug treatment was administered in 350 (9.9%) cases of envenomation in pregnant women compared with 21,381 (24.4%) of non-pregnant patients. Antihistamines were less likely to be used in pregnant patients with scorpion (1.8% v. 9.2%), hymenoptera (bee, wasp, or hornet) (12.4% v. 37.1%), black widow spider (2.8% v. 8.1%), and caterpillar (10.4% v. 37.7%) exposures. There was an increased likelihood of antivenom use during pregnancy with rattlesnake envenomations (85.0% v. 58.9%) and black widow spider bites (4.8% v. 2.2%). There were no maternal deaths, and most maternal outcomes were coded as having no (1.0%) or minor (87.6%) effects. Three fetal deaths occurred, all following snakebites and all before 20 weeks gestation. Two were attributed as related, and one as of uncertain relationship to the exposure, by the managing poison centers. Most envenomations caused no or minor effects to pregnant women.


Assuntos
Picadas de Escorpião/epidemiologia , Mordeduras de Serpentes/epidemiologia , Picada de Aranha/epidemiologia , Adulto , Animais , Feminino , Humanos , Centros de Controle de Intoxicações , Gravidez , Estados Unidos/epidemiologia
2.
ASAIO J ; 43(4): 338-44, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9242950

RESUMO

Cardiomyoplasty is a new surgical treatment for heart failure in which skeletal muscle assists the heart. However, for the first 2 weeks postoperatively, the latissimus dorsi muscle (LDM) remains unstimulated, and during the next 2 weeks, the LDM is stimulated with only one pulse every other heart beat. Thus, for the initial 4 postoperative weeks, minimal systolic assistance is provided. The present study determined if the LDM is capable of providing early assistance. Cardiomyoplasty surgery involves severing the perforating intercostal arteries to the LDM, detaching the LDM from its distal insertion, and wrapping it around the heart. At each of these steps, we measured LDM force development, shortening, and blood flow in six dogs. At control, LDM shortening, work, and power decreased during a 2 min fatigue test: fatigue indices (final/ initial value) for shortening, work, and power were 47.6 +/- 6.9%, 47.5 +/- 7.1%, and 46.9 +/- 6.6%, respectively. Blood flow increased in the proximal (P), mid (M), and distal (D) LDM during the fatigue test. After partial vascular isolation, initial shortening, work, and power decreased by 29.4%, 32.5%, and 31.7% from their respective control values. During the fatigue test, fatigue indices for shortening, work, and power were 24.7 +/- 3.3%, 19.5 +/- 4.6%, and 22.2 +/- 4.7%, respectively, all significantly (p < 0.05) less than control values. Resting blood flows were unaltered. During exercise, flow to the P increased, whereas flow did not increase in M (p < 0.05). Loss of LDM function was most apparent after mobilizing and reattaching the muscle. Initial shortening, work, and power significantly decreased (p < 0.05) by 74.1%, 76.8%, and 74.4%, from their respective control values. During a fatigue test, final values for shortening, work, and power were all near zero. Resting blood flow decreased in the M and D (p < 0.05) and, during exercise, blood flow increased only in P. Thus, LDM function was severely depressed during the isolation procedure. This functional loss is associated with inadequate blood flow responses. Therefore, preconditioning and/or revascularization is needed if the LDM is to provide cardiac assistance shortly after cardiomyoplasty surgery.


Assuntos
Cardiomioplastia , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/fisiologia , Animais , Cães , Estimulação Elétrica , Precondicionamento Isquêmico , Fadiga Muscular/fisiologia , Revascularização Miocárdica , Condicionamento Físico Animal , Complicações Pós-Operatórias/prevenção & controle , Fluxo Sanguíneo Regional
3.
Nano Lett ; 7(6): 1586-90, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17497818

RESUMO

We demonstrate the room-temperature control of magnetization reversal with an electric field in an epitaxial nanostructure consisting of ferrimagnetic nanopillars embedded in a ferroelectric matrix. This was achieved by combining a weak, uniform magnetic field with the switching electric field to selectively switch pillars with only one magnetic configuration. On the basis of these experimental results, we propose to use an electric field to assist magnetic recording in multiferroic systems with high perpendicular magnetic anisotropy.


Assuntos
Armazenamento e Recuperação da Informação/métodos , Compostos de Ferro/química , Compostos de Ferro/efeitos da radiação , Magnetismo/instrumentação , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Nanotecnologia/instrumentação , Cristalização/métodos , Campos Eletromagnéticos , Desenho de Equipamento , Análise de Falha de Equipamento , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Nanotecnologia/métodos , Tamanho da Partícula , Propriedades de Superfície
4.
Phys Rev Lett ; 99(21): 217601, 2007 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-18233258

RESUMO

We have studied the stability of domains and domain walls in multiferroic BiFeO3 thin films using a combination of piezoelectric force microscopy and phase-field simulations. We have discovered that a film-substrate misfit strain may result in a drastically different thermodynamic stability of two parallel domain walls with the same orientation. A fundamental understanding of the underlying physics, the stress distribution in a domain structure, leads to a novel approach to control the ferroelastic domain stability in the multiferroic BiFeO3 system.

5.
Nat Mater ; 5(10): 823-9, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16951676

RESUMO

Multiferroic materials, which offer the possibility of manipulating the magnetic state by an electric field or vice versa, are of great current interest. In this work, we demonstrate the first observation of electrical control of antiferromagnetic domain structure in a single-phase multiferroic material at room temperature. High-resolution images of both antiferromagnetic and ferroelectric domain structures of (001)-oriented multiferroic BiFeO3 films revealed a clear domain correlation, indicating a strong coupling between the two types of order. The ferroelectric structure was measured using piezo force microscopy, whereas X-ray photoemission electron microscopy as well as its temperature dependence was used to detect the antiferromagnetic configuration. Antiferromagnetic domain switching induced by ferroelectric polarization switching was observed, in agreement with theoretical predictions.

6.
Br Poult Sci ; 38(4): 412-6, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9347151

RESUMO

1. An experiment was conducted to determine the temperature for wet extrusion of full-fat soyabeans (FFS) needed to produce maximum chicken performance. 2. FFS were either unprocessed or extruded at 5 different temperatures (118 degrees, 120 degrees, 122 degrees, 126 degrees and 140 degrees C) in a wet extruder. Diets were prepared with the different FFS, and a diet prepared with soyabean meal (SBM) was included as a control. The 7 experimental diets were fed to individual groups of 40 chickens each, for a period of 35 d. Trypsin inhibitor activity (TIA), urease activity (UA), and protein solubility in potassium hydroxide (PS) were measured in all FFS and in the SBM. 3. Diets prepared with raw FFS and FFS extruded at 118 degrees and 120 degrees C resulted in significantly lower body weights and in pancreatic hypertrophy; maximum growth rate was obtained with FFS extruded at 122 degrees and 126 degrees C, while minimum pancreas weight was seen in chickens fed FFS extruded at 140 degrees C. 4. Although TIA, UA, and PS all decreased with increasing temperature of extrusion, TIA provided the best prediction of the feeding value of soyabeans for chickens.


Assuntos
Ração Animal , Glycine max , Animais , Galinhas , Manipulação de Alimentos/métodos , Hidróxidos , Carne , Valor Nutritivo , Proteínas de Vegetais Comestíveis/química , Compostos de Potássio , Análise de Regressão , Solubilidade , Temperatura , Inibidores da Tripsina/análise , Urease/análise
7.
Hereditas ; 138(2): 133-7, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12921165

RESUMO

Melipona mandacaia is a stingless bee endemic to northeast Brasil. We describe the M. mandacaia karyotype using C-banding technique. fluorochrome staining and treatment with restriction enzymes and discuss the position of this species in the context of the phylogeny of the genus. Melipona mandacaia has 2n = 18 (14 SM + 2 M + 2 A). Heterochromatin was detected in the pericentromeric region of pairs 1, 2 and 8 and in the form of small blocks in the remaining pairs. Staining with base-specific fluorochromes showed that this heterochromatin was rich AT (QM and DAPI), except in the region corresponding to the NOR which was rich GC (CMA3) and was cleaved by the HaeIII enzyme. Melipona mandacaia is a member of Group I Melipona. Treatment with DraI/Giemsa discloses a larger number of bands than treatment with DraI/QM. Pre-cleavage with DraI gave rise to a larger number of bands following QM staining; a circumstance evidently due to a removal of the DNA-protein complex that prevented the association of the fluorochrome with AT-rich DNA. The results highlight the complex nature of heterochromatin.


Assuntos
Bandeamento Cromossômico , Heterocromatina/genética , Himenópteros/genética , Animais , Cerebelo/química , Corantes Fluorescentes , Cariotipagem , Metáfase/genética , Região Organizadora do Nucléolo/genética , Filogenia , Mapeamento por Restrição , Coloração e Rotulagem
8.
J Surg Res ; 67(2): 163-8, 1997 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-9073563

RESUMO

The following experiments were conducted to determine whether, and the mechanisms through which, endogenous peptides alter coronary artery blood flow. Ultrasonic transit time probes were placed around the ascending aorta and left anterior descending coronary artery in groups of anesthetized, open-chest dogs. A Millar pressure catheter monitored left ventricular developed pressure. Intracoronary artery bolus injections of adenosine (a purinergic receptor activator), pinacidil (a KATP channel activator), calcitonin gene-related peptide (CGRP; which causes vascular smooth muscle relaxation by intracellular increases in cyclic-AMP), and adrenomedullin (mechanism unknown) each significantly (P < 0.05, Student's t test) increased coronary blood flow in a dose-dependent fashion, without altering systemic hemodynamic measurements. Intracoronary artery injection of U37883A (a KATP channel antagonist) significantly (P < 0.05) blocked the coronary vasodilator responses to adenosine, adrenomedullin, and pinacidil. Intracoronary xanthine amine congener (an adenosine receptor antagonist) blocked only the responses to adenosine and adrenomedullin, not pinacidil. Intracoronary CGRP8-37 (CGRP receptor antagonist) blocked only the vasodilator response to CGRP. These data suggest that the coronary vasodilator effect of adrenomedullin is initiated first by activation of adenosine receptors, and subsequently through KATP channels-not by activation of CGRP receptors. That there were no changes in left ventricular developed pressure or in systemic hemodynamics after intracoronary artery infusions of adrenomedullin indicates that this endogenous peptide may have clinical utility in facilitating myocardial protection or preconditioning.


Assuntos
Vasos Coronários/fisiologia , Peptídeos/fisiologia , Canais de Potássio/fisiologia , Receptores Purinérgicos P1/fisiologia , Vasodilatação/fisiologia , Adamantano/análogos & derivados , Adamantano/farmacologia , Trifosfato de Adenosina/metabolismo , Adrenomedulina , Animais , Peptídeo Relacionado com Gene de Calcitonina/farmacologia , Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Circulação Coronária/efeitos dos fármacos , Circulação Coronária/fisiologia , Vasos Coronários/efeitos dos fármacos , Cães , Morfolinas/farmacologia , Fragmentos de Peptídeos/farmacologia , Peptídeos/administração & dosagem , Peptídeos/farmacologia , Canais de Potássio/efeitos dos fármacos , Receptores Purinérgicos P1/efeitos dos fármacos , Resistência Vascular/efeitos dos fármacos , Resistência Vascular/fisiologia , Vasodilatação/efeitos dos fármacos , Xantinas/farmacologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA