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Magnetic systems with competing anisotropies generally exhibit asymmetry between the maximum amplitudes of the right and left maxima in a magnetoimpedance curve. Small errors in positioning the samples at the experimental setup may also produce such asymmetry. In this work, we present a study on the sources of the asymmetry between magnetoimpedance peaks in systems that present the exchange bias phenomenon, by comparing a phenomenological model to experimental data. A set of samples with different repetitions of the NiFe/FeMn exchange-biased bilayer was used in this study. From the frequency evolution of the asymmetry, together with magnetization curves, we were able to identify the sources for the observed magnetoimpedance asymmetry found on our experimental data.
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OBJECTIVES: Major depressive disorder (MDD) is a multifactorial syndrome with significant interactions between genetic and environmental factors. This study specifically investigates the association between family history of alcohol problems (FHAP) and family history of depression (FHD), and how these relate to different clusters of depressive symptoms. METHODS: Correlations between FHAP and FHD and different clusters of the Beck Depression Inventory (BDI) were studied. We sampled 333 employees from a general hospital who had been receiving a psychiatric consultation between 2005 and 2012. Analysis of variance (ANOVA) and Analysis of covariance (ANCOVA) models were conducted to explore these correlations. RESULTS: There was a significant positive correlation between FHAP and BDI affective score. This result remained significant even after the adjustment for other variables considered as important factors for MDD, such as gender, age, marital status, education, ethnic group and FHD. More specifically, FHAP was correlated with dissatisfaction and episodes of crying among the affective symptoms. FHAP showed no statistical difference in any of the other clusters score or in the BDI total score. Moreover, as expected, we found a correlation between FHD and BDI total score and Somatic and Cognitive clusters. CONCLUSION: FHAP should be routinely investigated in individuals presenting with depressive symptoms. This is especially important in cases presenting with dissatisfaction and episodes of crying in patients who do not endorse criteria for MDD. Due to study limitations, the findings require replication by neurobiological, epidemiological and clinical studies.
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Transtornos Relacionados ao Uso de Álcool , Transtorno Depressivo Maior , Depressão , Humanos , Escalas de Graduação PsiquiátricaRESUMO
The coexistence of plant species in tropical rainforests is related to specific abiotic resources, varying according to the occurrence microhabitat of each species. Light quality is the main abiotic factor influencing germination of small seeds; however, studies often do not discriminate its effect from that of light irradiance. This study compared specific requirements for seed germination of ten small-seeded species, with restricted occurrence in only one of three contrasting microhabitats: forest understorey, edge of clearings and open areas. Laboratory experiments were carried out to test temperature regime (constant or fluctuating), light quality (R:FR) and light irradiance (PAR), which reproduce high and low conditions commonly found in the microhabitats. Seed germination of all species occurred between 20 and 30 °C, only seeds of open area species were able to germinate at 35 °C and no species required alternating temperatures to germinate. Irrespective of species and microhabitat, a decrease in the R:FR reduced the germination percentage; however, there were differences in the capacity to germinate at low R:FR. The values of R:FR50% were higher for open area and edge species (0.441-0.345) than for understorey species (0.181-0.109), with few exceptions. For all species and most of the tests, germination was not influenced by PAR. Light quality is the most important light signal for germination of small seeds; irradiance has little effect. Our results suggest two distinct patterns of germination for small-seeded species: open area and edge species are light-demanding and require high R:FR to germinate, while understorey species are shade-tolerant and germinate at low R:FR. These differences are responsible for distinct microhabitat occurrence and help to explain the coexistence of species in tropical forests.
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Germinação , Sementes , Florestas , TemperaturaRESUMO
To mitigate anthropogenic impacts on plant diversity in tropical montane grasslands, one of the most threatened ecosystems in Brazil, it will be essential to develop ex situ conservation strategies to preserve wild species. The lack of basic research on the seed storage behaviour of grassland species may, however, limit their use for reintroduction and restoration projects. We investigated seed storage behaviour at the community level by comparing the effects of cold-low RH (10 °C; 10% RH) and freezing-low RH (20 °C; 10% RH) conditions on seed viability, germination and dormancy of 47 species. Fresh seeds of 43% of the species showed primary dormancy. More than half of the species showed high seed survival responses (viability >60%) under both storage temperatures. Despite a variety of dormancy responses among the different species, the low RH storage conditions tested released dormancy for most species during 12- and 30-month storage times. Multivariate analysis of the best (freezing-low RH, 30 months) storage condition evidenced the formation of five distinct groups, three with species having high conservation potential in seed banks. Although further studies are needed to test dormancy-breaking treatments and improve seed conservation practices, this first approach to assessing seed banking techniques could contribute to demand for locally adapted seeds for ecological restoration projects in tropical montane grasslands.
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Germinação , Dormência de Plantas , Brasil , Ecossistema , Pradaria , Sementes , TemperaturaRESUMO
OBJECTIVE: Given the complex and unclear etiology of neck pain, it is important to understand the differences in central sensitization as well as psychosocial factors in individuals with chronic neck pain and healthy controls. The purpose of this study was to benchmark differences in central sensitization, psychosocial factors, and range of motion between people with nonspecific chronic neck pain and healthy controls and to analyze the correlation between pain intensity, neck disability, and psychosocial factors in people with chronic neck pain. METHODS: Thirty individuals with chronic neck pain and 30 healthy controls were included in this case-control study. Outcome measures were as follows: central sensitization (pressure pain threshold, temporal summation, and conditioned pain modulation), psychosocial factors (depressive symptoms, pain catastrophizing, and quality of life), and active cervical range of motion. RESULTS: People with neck pain had lower local pressure pain threshold, a decrease in conditioned pain modulation, more depressive symptoms, greater pain catastrophizing, lower quality of life, and reduced range of motion for neck rotation when compared with healthy controls. In people with neck pain, moderate correlations were observed between pain intensity and quality of life (ρ = -0.479), disability and pain catastrophizing (ρ = 0.379), and disability and quality of life (ρ = -0.456). CONCLUSIONS: People with neck pain have local hyperalgesia, impaired conditioning pain modulation, depressive symptoms, pain catastrophizing, low quality of life, and reduced active range of motion during neck rotation, which should be taken into account during assessment and treatment. IMPACT: This study shows that important outcomes, such as central sensitization and psychosocial factors, should be considered during assessment and treatment of individuals with nonspecific chronic neck pain. In addition, pain intensity and neck disability are correlated with psychosocial factors.
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Progesterone (P4) plays a key role in pregnancy establishment and maintenance; during early pregnancy, P4 stimulates the production and release of uterine secretions necessary for conceptus growth prior to implantation; therefore, exogenous P4 supplementation may improve embryo development. This study evaluated the effects of supplementation during early pregnancy with long-acting injectable progesterone or altrenogest on embryonic characteristics of sows and gilts. Thus, a total of 32 sows and 16 gilts were used. On day 6 of pregnancy sows and gilts were allocated to one of the following groups: non-supplemented; supplemented with 20 mg of altrenogest, orally, from days 6 to 12 of pregnancy; supplemented with 2.15 mg/kg of long-acting injectable progesterone on day 6 of pregnancy. Animals were killed on day 28 of pregnancy, and ovulation rate, embryo survival, embryo weight, crown-to-rump length, uterine glandular epithelium and endometrial vascularization were assessed. Treatments had no effect on pregnancy rate, embryo survival or endometrial vascular density (P > 0.05). Non-supplemented gilts presented larger and heavier embryos compared to gilts from supplemented groups (P < 0.05). Sows in the altrenogest group presented larger and heavier embryos compared to non-supplemented sows and sows supplemented with long-acting injectable progesterone. In conclusion, supplementation of sows and gilts with progestagen from day 6 of pregnancy can be used as a means to improve embryo survival without deleterious effects.
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Implantação do Embrião/efeitos dos fármacos , Desenvolvimento Embrionário/efeitos dos fármacos , Prenhez , Suínos/fisiologia , Acetato de Trembolona/análogos & derivados , Animais , Suplementos Nutricionais , Embrião de Mamíferos , Endométrio , Feminino , Ovulação/fisiologia , Gravidez , Taxa de Gravidez , Prenhez/efeitos dos fármacos , Progestinas/administração & dosagem , Progestinas/farmacologia , Acetato de Trembolona/administração & dosagem , Acetato de Trembolona/farmacologiaRESUMO
Seminal plasma (SP), the fluid that surrounds the sperm cells, is known to exert substantial influence on sperm physiology. The SP has a pivotal role in sperm function in vivo, and due to its components, it functions in an ambiguous manner in vitro, simultaneously possessing deleterious and beneficial effects. This experiment aimed to describe the differences between the presence or absence of SP from the sperm-rich fraction on some spermatozoa characteristics (kinetics, plasma and acrosome membrane integrity, lipid peroxidation and capacitation-like changes). Furthermore, this experiment focused on distinguishing the effects of SP on the variables evaluated from the effects of centrifugation during SP removal. Total and progressive sperm motility, as well as integrity of plasma and acrosome membranes, were less (P < 0.05) in the absence of SP. Membrane lipid peroxidation (P < 0.05) and sperm membrane stability (P < 0.05) did not differ among treatments. The SP from the sperm-rich fraction is important for the maintenance of adequate structural and functional characteristics of extended liquid boar semen and should be present in seminal doses throughout storage. Furthermore, the detrimental effect on the variables evaluated was caused solely by the absence of SP and not by the process of removal through centrifugation at 500 x g for 10 min.
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Criopreservação , Análise do Sêmen , Preservação do Sêmen , Sêmen/fisiologia , Espermatozoides/citologia , Animais , Centrifugação , Criopreservação/métodos , Criopreservação/veterinária , Masculino , Sêmen/citologia , Preservação do Sêmen/métodos , Preservação do Sêmen/veterinária , Contagem de Espermatozoides , Motilidade dos Espermatozoides/fisiologia , SuínosRESUMO
In spite of the possibility of triggering thromboembolic events, many professionals indicate the suspension of antiplatelet agents before dental surgical procedures. The aim of this study was to perform a quantitative assessment of intraoperative bleeding in patients on dual antiplatelet therapy. A case-control study was conducted in patients on dual antiplatelet therapy (APT group) and in patients who did not use these medications (control group). The following examinations were requested: complete blood cell count, blood coagulation tests, and platelet aggregation. The quantity of bleeding was measured intraoperatively by collection of aspirated blood. The mean volume of blood lost during the surgical procedure was 6.10ml in the control group and 16.07ml in the APT group (P=0.002). The mean volume of blood lost per minute was 0.60ml/min in the control group and 1ml/min in the APT group (P=0.001), with local haemostatic methods being sufficient to control the bleeding. There was no postoperative bleeding complication in any case. Patients on dual antiplatelet therapy presented a larger volume of bleeding, but this could be controlled by means of local haemostatic measures. Therefore, there is no need to stop either of the two dual antiplatelet therapy medications before dental extractions.
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Aspirina/administração & dosagem , Perda Sanguínea Cirúrgica/estatística & dados numéricos , Hemorragia/epidemiologia , Inibidores da Agregação Plaquetária/administração & dosagem , Ticlopidina/análogos & derivados , Extração Dentária , Doenças Cardiovasculares/tratamento farmacológico , Estudos de Casos e Controles , Clopidogrel , Assistência Odontológica para Doentes Crônicos , Feminino , Hemostasia Cirúrgica/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Ticlopidina/administração & dosagemRESUMO
In spite of the possibility of triggering thromboembolic events, many professionals indicate the suspension of antiplatelet agents before dental surgical procedures. The aim of this study was to perform a quantitative assessment of intraoperative bleeding in patients on dual antiplatelet therapy. A case-control study was conducted in patients on dual antiplatelet therapy (APT group) and in patients who did not use these medications (control group). The following examinations were requested: complete blood cell count, blood coagulation tests, and platelet aggregation. The quantity of bleeding was measured intraoperatively by collection of aspirated blood. The mean volume of blood lost during the surgical procedure was 6.10ml in the control group and 16.07ml in the APT group (P=0.002). The mean volume of blood lost per minute was 0.60ml/min in the control group and 1ml/min in the APT group (P=0.001)...
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Complicações Intraoperatórias , Doenças das Artérias Carótidas , Extração Dentária , Hemorragia , Técnicas HemostáticasRESUMO
AIM: To evaluate and compare the immunoexpression of tryptase in samples of periapical granulomas (PGs) and radicular cysts (RCs) correlating it with the type of lesion, localization, intensity of the inflammatory infiltrate and thickness of the cystic epithelial lining, in order to gain insight into the phlogistic role of these cells in the lesions studied. METHODOLOGY: Twenty-five PGs and twenty-five RCs obtained from human teeth without endodontic treatment were submitted to morphological and immunohistochemical analysis using anti-tryptase antibody. Mast cells were identified and counted in three regions: intra-epithelial, central/superficial and deep portions. The data were analysed using the Mann-Whitney U-test (P < 0.05). RESULTS: In comparison with RCs, PGs exhibited higher immunoexpression of tryptase-positive mast cells located in both central/superficial and deep regions (P < 0.001 and P < 0.001, respectively). When considering the total number of mast cells and disregarding the location, the number of tryptase-positive mast cells increased gradually from RCs to PGs (P < 0.001). Lesions with inflammatory infiltrate grade III had greater number of tryptase-positive mast cells located in both central/superficial and deep regions than lesions with inflammatory infiltrates grade II (P = 0.045 and P = 0.025). When the location was ignored, the lesions with inflammatory infiltrate grade III also exhibited higher immunostaining of tryptase-positive mast cells (P = 0.01). CONCLUSIONS: Tryptase-positive mast cells were present in chronic periapical lesions in a larger number in periapical granulomas than in radicular cysts, in both central/superficial and deep regions.
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Mastócitos/enzimologia , Mastócitos/imunologia , Granuloma Periapical/enzimologia , Granuloma Periapical/imunologia , Cisto Radicular/enzimologia , Cisto Radicular/imunologia , Triptases/metabolismo , Epitélio/metabolismo , Humanos , Técnicas Imunoenzimáticas , InflamaçãoRESUMO
This study evaluated the effects of dietary organic selenium (Se) on viability of chilled boar semen. Twelve boars were divided into three groups: control (CON), 0.3 mg kg(-1) sodium selenite; inorganic (INO), 0.5 mg kg(-1) sodium selenite and organic (ORG), 0.5 mg kg(-1) Se yeast. The experiment was conducted within 10 weeks, and analysis was performed fortnightly, in storage semen by 72 h. No effect was observed on motility; however, straightness and linearity percentages were higher (P < 0.05) in the animals receiving CON diet compared with INO group. Percentages of cells with both plasma and acrosomal intact membranes, lipidic membrane peroxidation and mitochondrial membrane potential were similar on all treatments. Animals receiving CON diet presented higher (P < 0.05) values of ATP when compared with INO group. The PHGPx was higher (P < 0.05) in animals that received ORG in comparison with INO group. In conclusion, organic selenium supplementation increases PHGPx but does not improve chilled semen viability in 72 h.
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Antioxidantes/farmacologia , Suplementos Nutricionais , Glutationa Peroxidase/efeitos dos fármacos , Selênio/farmacologia , Espermatozoides/efeitos dos fármacos , Acrossomo/efeitos dos fármacos , Animais , Sobrevivência Celular/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Masculino , Fosfolipídeo Hidroperóxido Glutationa Peroxidase , Análise do Sêmen , Preservação do Sêmen , Motilidade dos Espermatozoides/efeitos dos fármacos , Espermatozoides/enzimologia , SuínosRESUMO
The aim of this study was to evaluate the reproductive performance of three parities of gilts treated or not treated with gonadotropin to induce puberty. Sixty gilts received 600 IU of equine chorionic gonadotropin (eCG) followed by 2.5 mg of porcine luteinizing hormone (LH) 72 h later. Fifty-nine other gilts were exposed only to a mature boar for 15 min twice daily. Artificial insemination (AI) was performed at 0, 12 and 24 h after the detection of oestrus, and gestation was confirmed by ultrasound after 35 days. Sows were inseminated at the first post-weaning oestrus. The total numbers of piglets born, piglets born alive, stillborn, mummified foetuses, as well as pregnancy and farrowing rates were evaluated for each of the three parities. Culling rates, farrowing intervals and weaning-to-oestrous intervals (WEI) were also analysed. Mean age at puberty and oestrous manifestation were not significantly different between treatments (p = 0.0639; 179.20 ± 17.52 compared with 173.96 ± 16.94, 91.66% compared with 94.92%) across the experimental period. However, females that underwent puberty induction showed modest increases both in the number of total pigs born and in the number of piglets born alive. In conclusion, puberty induction through exogenous gonadotropin administration in field conditions did not induce a more concentrated first oestrous manifestation, but trended to a modest increase in the number of pigs born alive in the first parity and a reduced culling rate during the first gestation.
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Gonadotropina Coriônica/farmacologia , Hormônio Luteinizante/farmacologia , Paridade/fisiologia , Maturidade Sexual/efeitos dos fármacos , Suínos/fisiologia , Animais , Ciclo Estral , Feminino , Inseminação Artificial/veterinária , GravidezRESUMO
The objective was to determine the effect of sequence of insemination after simultaneous thawing of multiple 0.5 mL semen straws on conception rate in suckled multiparous Nelore cows. The effect of this thawing procedure on in vitro sperm characteristics was also evaluated. All cows (N = 944) received the same timed AI protocol. Ten straws (0.5 mL) of frozen semen from the same batch were simultaneously thawed at 36 °C, for a minimum of 30 sec. One straw per cow was used for timed AI. Frozen semen from three Angus bulls was used. Timed AI records included sequence of insemination (first to tenth) and time of semen removal from thawing bath. For laboratory analyses, the same semen batches used in the field experiment were evaluated. Ten frozen straws from the same batch were thawed simultaneously in a thawing unit identical to that used in the field experiment. The following sperm characteristics were analyzed: sperm motility parameters, sperm thermal resistance, plasma and acrosomal membrane integrity, lipid peroxidation, chromatin structure, and sperm morphometry. Based on logistic regression, there were no significant effects of breeding group, body condition score, AI technician, and sire on conception rate, but there was an interaction between sire and straw group (P = 0.002). Semen from only one bull had decreased (P < 0.05) field fertility for the group of straws associated with the longest interval from thawing to AI. However, the results of the laboratory experiment were unable to explain the findings of the field experiment. Sperm width:length ratio of morphometric analysis was the single sperm characteristic with a significant interaction between sire and straw group (P = 0.02). It was concluded that sequence of insemination after simultaneous thawing of 10 semen straws can differently affect conception rates at timed AI, depending on the sire used. Nevertheless, the effects of this thawing environment on in vitro sperm characteristics, remain to be further investigated.
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Bovinos/fisiologia , Criopreservação/veterinária , Fertilização/fisiologia , Temperatura Alta , Inseminação Artificial/veterinária , Preservação do Sêmen/veterinária , Acrossomo/ultraestrutura , Animais , Cruzamento/métodos , Cromatina/ultraestrutura , Criopreservação/métodos , Feminino , Inseminação Artificial/métodos , Masculino , Paridade , Gravidez , Preservação do Sêmen/métodos , Motilidade dos Espermatozoides , Espermatozoides/anormalidades , Espermatozoides/fisiologia , Espermatozoides/ultraestrutura , Fatores de TempoRESUMO
BACKGROUND AND OBJECTIVE: Smokers are more predisposed than nonsmokers to infection with Porphyromonas gingivalis, one of the most important pathogens involved in the onset and development of periodontitis. It has also been observed that tobacco, and tobacco derivatives such as nicotine and cotinine, can induce modifications to P. gingivalis virulence. However, the effect of the major compounds derived from cigarettes on expression of protein by P. gingivalis is poorly understood. Therefore, this study aimed to evaluate and compare the effects of nicotine and cotinine on the P. gingivalis proteomic profile. MATERIAL AND METHODS: Total proteins of P. gingivalis exposed to nicotine and cotinine were extracted and separated by two-dimensional electrophoresis. Proteins differentially expressed were successfully identified through liquid chromatography-mass spectrometry and primary sequence databases using MASCOT search engine, and gene ontology was carried out using DAVID tools. RESULTS: Of the approximately 410 protein spots that were reproducibly detected on each gel, 23 were differentially expressed in at least one of the treatments. A particular increase was seen in proteins involved in metabolism, virulence and acquisition of peptides, protein synthesis and folding, transcription and oxidative stress. Few proteins showed significant decreases in expression; those that did are involved in cell envelope biosynthesis and proteolysis and also in metabolism. CONCLUSION: Our results characterized the changes in the proteome of P. gingivalis following exposure to nicotine and cotinine, suggesting that these substances may modulate, with minor changes, protein expression. The present study is, in part, a step toward understanding the potential smoke-pathogen interaction that may occur in smokers with periodontitis.
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Proteínas de Bactérias/análise , Cotinina/farmacologia , Nicotina/farmacologia , Porphyromonas gingivalis/efeitos dos fármacos , Biossíntese de Proteínas/efeitos dos fármacos , Proteoma/efeitos dos fármacos , Eletroforese em Gel Bidimensional , Perfilação da Expressão Gênica , Espectrometria de Massas/métodos , Estresse Oxidativo/efeitos dos fármacos , Porphyromonas gingivalis/química , Porphyromonas gingivalis/genética , Virulência/efeitos dos fármacosRESUMO
This work consisted in the preparation of platinum-based catalysts supported on carbon (Vulcan XC-72) and investigation of their physicochemical and electrochemical properties. Catalysts of the C/Pt-Ni-Sn-Me (Me = Ru or Ir) type were prepared by the Pechini method at temperature of 350°C. Four different compositions were homemade: C/Pt(60)Sn(10)Ni(30), C/Pt(60)Sn(10)Ni(20)Ru(10), C/Pt(60)Sn(10)Ni(10)Ru(20), and C/Pt(60)Sn(10)Ni(10)Ir(20). These catalysts were electrochemically and physically characterized by cyclic voltammetry (CV), chronoamperometry (CA) in the presence of glycerol 1.0 mol dm(-3), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). XRD results showed the main peaks of face-centered cubic Pt. The particle sizes obtained from XRD and HRTEM experiments were close to values ranging from 3 to 8.5 nm. The CV results indicate behavior typical of Pt-based catalysts in acid medium. The CV and CA data reveal that quaternary catalysts present the highest current density for the electrooxidation of glycerol.
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Eletroquímica/métodos , Glicerol/química , Carbono/química , Catálise , Microscopia Eletrônica de Transmissão , Nanotecnologia/métodos , Oxirredução , Tamanho da Partícula , Platina/química , Difração de Raios XRESUMO
OBJECTIVES: Cocaine is a commonly used illicit drug that leads to the most emergency department (ED) visits. Chest pain is the most common presentation, reported in 40% of patients. Our aim was to evaluate the incidence of previous myocardial infarction among young cocaine users (18-40 years) with cocaine-associated chest pain by the assessment of myocardial fibrosis by cardiovascular MRI. Second, we also intended to evaluate the coronary tree by CT angiography (CTA). METHODS: 24 cocaine users (22 males) who frequently complained about cocaine-associated chest pain underwent CTA and cardiovascular MRI. Mean age of patients was 29.7 years and most of them (79%) had frequently used inhalatory cocaine. RESULTS: The calcium score turned out to be positive in only one patient (Agatston=54). Among the coronary segments evaluated, only one patient had calcified plaques at the anterior descending coronary artery (proximal and medium segments). Assessment of regional ventricular function by the evaluation of 17 segments was normal in all patients. None of the patients showed myocardial delayed enhancement, indicative of myocardial fibrosis. CTA therefore confirmed the low cardiovascular risk of these patients, since most of them (96%) had no atherosclerosis detected by this examination. Only one patient (4%) had coronary atherosclerosis detected, without significant coronary stenosis. CONCLUSION: Cardiovascular MR did not detect the presence of delayed enhancement indicative of myocardial fibrosis among young cocaine users with low cardiovascular risk who had complained of cocaine-associated chest pain.
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Transtornos Relacionados ao Uso de Cocaína/complicações , Cocaína/efeitos adversos , Angiografia Coronária/métodos , Angiografia por Ressonância Magnética/métodos , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/etiologia , Adolescente , Adulto , Fatores Etários , Doenças Cardiovasculares/induzido quimicamente , Doenças Cardiovasculares/diagnóstico por imagem , Doenças Cardiovasculares/fisiopatologia , Dor no Peito/induzido quimicamente , Dor no Peito/diagnóstico , Transtornos Relacionados ao Uso de Cocaína/diagnóstico , Feminino , Humanos , Incidência , Masculino , Infarto do Miocárdio/fisiopatologia , Projetos Piloto , Estudos Prospectivos , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Tomografia Computadorizada por Raios X/métodos , Adulto JovemRESUMO
The objective of this study was to evaluate the quality of bovine frozen-thawed sperm cells after Percoll gradient centrifugation. Frozen semen doses were obtained from six bulls of different breeds, including three taurine and three Zebu animals. Four ejaculates per bull were evaluated before and after discontinuous Percoll gradient centrifugation. Sperm motility was assessed by computer-assisted semen analysis and the integrity of the plasma and acrosomal membranes, as well as mitochondrial function, were evaluated using a combination of fluorescent probes propidium iodide, fluorescein isothiocyanate-conjugated Pisum sativum agglutinin and 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide. The procedure of Percoll gradient centrifugation increased the percentage of total and progressive sperm motility, beat frequency, rectilinear motility, linearity and rapidly moving cells. In addition, the percentage of cells with intact plasma membrane and mitochondrial membrane potential was increased in post-centrifugation samples. However, the percentage of sperm cells with intact acrosomal membrane was markedly reduced. The method used selected the motile cells with intact plasma membrane and higher mitochondrial functionality in frozen-thawed bull semen, but processing, centrifugation and/or the Percoll medium caused damage to the acrosomal membrane.
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Análise do Sêmen/veterinária , Espermatozoides/fisiologia , Animais , Bovinos , Separação Celular/veterinária , Centrifugação com Gradiente de Concentração , Computadores , Criopreservação/veterinária , Corantes Fluorescentes , Masculino , Povidona , Preservação do Sêmen/veterinária , Dióxido de Silício , Motilidade dos EspermatozoidesRESUMO
Effect of seminal plasma addition after thawing on viability or cryocapacitation is not definitively established. This experiment was performed to verify the effect of adding seminal plasma, autologous or homologous (from an animal with good semen freezability). Five ejaculates from each of four stallions with proven fertility were collected and cryopreserved. The semen was subsequently thawed and divided into the following three treatment groups: no seminal plasma addition after semen thawing (NOSP); the addition of homologous seminal plasma after semen thawing (HSP) and the addition of autologous seminal plasma after semen thawing (ASP). The addition of 20% of seminal plasma led to an increase in the cell population that simultaneously show plasma and acrosomal membrane integrity (p < 0.05). The addition of seminal plasma did not alter the total motility, the amount of cells with mitochondrial membrane potential or the sperm velocities (average path velocity, straight-line velocity and curvilinear velocity). However, the beat/cross-frequency, straightness and linearity were reduced in ASP and HSP groups (p < 0.05). Unexpectedly, the addition of homologous seminal plasma reduced the proportion of cells with progressive motility (p < 0.05) and the addition of autologous seminal plasma reduced the amplitude of the lateral head displacement (p < 0.05). Based on the increase in the cell populations that had the plasma and acrosomal membrane integrity simultaneously identified in this study, we proposed that the addition of seminal plasma (autologous or homologous) into post-thawed semen before insemination could increase semen fertility.
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Criopreservação/veterinária , Cavalos/fisiologia , Sêmen/fisiologia , Motilidade dos Espermatozoides/fisiologia , Espermatozoides/fisiologia , Animais , Inseminação Artificial/veterinária , Masculino , Preservação do Sêmen/veterináriaRESUMO
This paper describes the preparation and application of a novel bioanode for use in ethanol/O(2) biofuel cells based upon immobilization of alcohol dehydrogenase (ADH) and polyamidoamine (PAMAM) dendrimers onto carbon cloth platforms. The power density measurements indicated a direct relationship between the amount of anchored ADH and the anode power values, which increased upon enzyme loading. The power density values ranged from 0.04 to 0.28 mW cm(-2), and the highest power density was achieved with the bioanode prepared with 28 U of ADH, which provided a power density of 0.28 mW cm(-2) at 0.3 V. The latter power output values were the maximum observed, even for higher enzyme concentrations. Stability of the bioanodes was quite satisfactory, since there was no appreciable reduction of enzymatic activity during the measurements. The method of bioanode preparation described here has proven to be very effective. The PAMAM dendrimer represents a friendly environment for the immobilization of enzymes, and it is stable and capable of generating high power density compared to other immobilization methods.
Assuntos
Álcool Desidrogenase/química , Fontes de Energia Bioelétrica , Dendrímeros/química , Eletrodos , Etanol/química , Proteínas de Saccharomyces cerevisiae/química , Enzimas Imobilizadas/química , Desenho de Equipamento , Análise de Falha de EquipamentoRESUMO
This paper describes the use of the electrostatic layer-by-layer (LbL) technique for the preparation of bioanodes with potential application in ethanol/O(2) biofuel cells. More specifically, the LbL technique was employed for immobilization of dehydrogenase enzymes and polyamidoamine (PAMAM) dendrimers onto carbon paper support. Both mono (anchoring only the enzyme alcohol dehydrogenase, ADH) and bi-enzymatic (anchoring both ADH and aldehyde dehydrogenase, AldDH) systems were tested. The amount of ADH deposited onto the Toray® paper was 95 ng cm(-2) per bilayer. Kinetic studies revealed that the LbL technique enables better control of enzyme disposition on the bioanode, as compared with the results obtained with the bioanodes prepared by the passive adsorption technique. The power density values achieved for the mono-enzymatic system as a function of the enzyme load ranged from 0.02 to 0.063 mW cm(-2) for the bioanode containing 36 ADH bilayers. The bioanodes containing a gas diffusion layer (GDL) displayed enhanced performance, but their mechanical stability must be improved. The bi-enzymatic system generated a power density of 0.12 mW cm(-2). In conclusion, the LbL technique is a very attractive approach for enzyme immobilization onto carbon platform, since it enables strict control of enzyme disposition on the bioanode surface with very low enzyme consumption.