148 resultados para dose finding
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An experiment was conducted to examine the luteolytic effectiveness of using low or micro doses of PGF2α when administered at the BAI HUI acupuncture point, which is frequently used to treat ovarian disturbances in veterinary acupuncture. The results indicate that PGF2α given at a very low micro dose of 0.5 mg (one tenth the conventional recommended dose) administered at the BAI HUI acupuncture point located at the sacral lumbar space is equally effective at inducing luteolysis in mid-luteal phase mares as conventional PGF2α i.m. treatment using a tenfold higher dose. Therefore, based on the results of the present study, we suggest that the BAI HUI sacrai lumbar route somehow provides an extremely efficient pathway for the drug to the ovarian level.
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In renovascular hypertensive rats, low doses of angiotensin converting enzyme (ACE) inhibitors have been found to prevent myocardial hypertrophy independent of blood pressure level. This finding would suggest humoral rather than mechanical control of myocyte growth. The aim of this study was to examine the effect of nonantihypertensive doses of ACE inhibitor on myocardial hypertrophy and necrosis in hypertensive rats. Renovascular hypertension (RHT) was induced in four-week-old Wistar rats. Twenty-eight animals were treated for four weeks with three doses of ramipril (0.01, 0.1 or 1. 0 mg/kg/day, which are unable to lower blood pressure. Fourteen animals were not treated (RHT group). A sham operated, age/sex-matched group was used as control (n = 10). Myocardial histology was analysed in 3 microm thick sections of the ventricle stained with either haematoxylin-eosin, reticulin silver stain or Masson's trichrome. There was a significant correlation between systolic blood pressure and left ventricular to body weight ratio in both sets of animals: untreated plus controls and ramipril-treated rats. ACE inhibition prevented myocyte and perivascular necrosis and fibrosis in a dose-dependent manner. We conclude that myocardial hypertrophy in rats with renovascular hypertension is directly related to arterial pressure, and that this relationship is not affected by nonantihypertensive doses of ACE inhibitor. Myocardial necrosis/fibrosis and coronary artery damage induced by angiotensin II are prevented by ACE inhibitor in a dose-dependent manner, despite the presence of arterial hypertension.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The objective of the present study was to optimize a radiographic technique for hand examinations using a computed radiography (CR) system and demonstrate the potential for dose reductions compared with clinically established technique. An exposure index was generated from the optimized technique to guide operators when imaging hands. Homogeneous and anthropomorphic phantoms that simulated a patient's hand were imaged using a CR system at various tube voltages and current settings (40-55 kVp, 1.25-2.8 mAs), including those used in clinical routines (50 kVp, 2.0 mAs) to obtain an optimized chart. The homogeneous phantom was used to assess objective parameters that are associated with image quality, including the signal difference-to-noise ratio (SdNR), which is used to define a figure of merit (FOM) in the optimization process. The anthropomorphic phantom was used to subjectively evaluate image quality using Visual Grading Analysis (VGA) that was performed by three experienced radiologists. The technique that had the best VGA score and highest FOM was considered the gold standard (GS) in the present study. Image quality, dose and the exposure index that are currently used in the clinical routine for hand examinations in our institution were compared with the GS technique. The effective dose reduction was 67.0%. Good image quality was obtained for both techniques, although the exposure indices were 1.60 and 2.39 for the GS and clinical routine, respectively.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Introduction: The request of three-dimensional images (3D) of the dentomaxillofacial complex has increased. Hence, new possibilities for assessment, treatment as well as follow-up after treatment have increased their importance with the use of cone beam computed tomography (CBCT). The images in two dimensions (2D) have inherent problems that can be solved with treedimensional images assessment. Objectives: To clarify the main doubts about the operational mechanism of complementary diagnostic method; to explain the advantages and disadvantages, to discuss the effective radiation dose and possible applications in orthodontia. Conclusion: The information generated by 2D images from the CBCT does not show differences that may endanger the orthodontic planning when compared with the images of 2D conventional radiographs. The effective radiation dose received by the patient should not be considered as a limiting factor of the tomography exam request.
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Pós-graduação em Fisiopatologia em Clínica Médica - FMB
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Introdução: A hanseníase é doença crônica que pode ter seu curso interrompido por episódios reacionais tipo 1 e 2 ou ENH, sendo que estes podem ser repetitivos, com conseqüentes danos ao paciente.A talidomida é a medicação de eleição para o controle, desde 1965. Objetivo: Evitar repetição de episódios reacionais. Material e Método: Após o controle da reação com dose tradicional, utilizou-se 100mg/d, pelo período de seis meses, com acompanhamento por seis meses após a suspensão. Resultados: Foram avaliados 42 pacientes MB, 39 (92,85%) da forma V e 3(7,15%) da D, que apresentaram ENH, como primeiro episódio ou repetição, 33(78,6%) do sexo masculino e9(21,4%) do feminino. As idades variaram de 18 a 84 anos, predomínio acima de 49 anos.Não se observou repetição em 100% dos pacientes durante o uso dessa dose.Durante a observação clinica, 33(78,6%)continuaram sem apresentar reação e9(21,4%), todos da forma V,a apresentaram, de forma leve,sem sinais e sintomas, controlada com antinflamatórios não hormonais. Não houve efeitos adversos. Conclusões: sugere-se o uso da talidomida, 100mg/ dia, como manutenção, que foi efetiva, impedindo a repetição das reações tipo 2.
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Purpose: To assess the bone mineral density (BMD) and bone mineral content (BMC) of female adolescents in use of standard low-dose combined oral contraceptives (COC) (EE 20 mcg/ Desogestrel 150 mcg) for a one-year period and to compare results against healthy controls matched for age and gender not in use of COC. Methods: A prospective, longitudinal study was conducted.Fifty adolescents, 12 to 20 years of age, were divided into a COC user group (n 35) and a control group (n 15) and submitted to a Bone Densitometry scan using dual-energy X-ray absorptiometry (DXA) at study inclusion and again at 12-month follow-up. Results: Results showed no statistically significant differences between the COC user and control groups at the initial moment. However, at 12-month follow-up, COC users showed negative mean percentage variation between initial and follow-up values for lumbar spine BMD and BMC of -1.09% and -1.58%, respectively, whereas controls had positive variations of +12.44% and +15.87%, respectively. Thus, the adolescents in use of COC showed a loss, albeit slight, in bone mass whereas the control group showed an increase. Conclusions: The low dose COC assessed (EE 20 mcg/Desogestrel 150 mcg) appeared to negatively affect the process of bone mass acquisition which occurs during adolescence.
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Background Low dose combined oral contraceptives (COC) can interfere in bone mass acquisition during adolescence. To evaluate bone mineral density (BMD) and bone mineral content (BMC) in female adolescents taking a standard low-dose (EE 20 µg/Desogestrel 150 µg) combination oral contraceptive (COC) over a one-year period and compare with healthy adolescents from the same age group not taking COCs.Methods A non-randomised parallel control study with one-year follow-up. Sixty-seven adolescents from 12 to 20 years of age, divided into COC users (n = 41) taking 20 µg EE/150 µg Desogestrel and non-user controls (n = 26), were evaluated through bone densitometry examinations at baseline and 12 months later. Comparisons between groups at study start was done through the Mann-Whitney test with significance level fixed at 5% or corresponding p value; comparisons between groups at study start and 12 months later used variations in median percentages for bone mass variables.Results COC users presented low bone mass acquisition in the lumbar spine and BMD and BMC median variations between baseline and at 12 months of 2.07% and +1.57% respectively whereas the control group presented variations of +12.16% and +16.84% for BMD and BMC, respectively, over the same period. The total body BMD and BMC presented similar evolution during the study in both groups. Statistical significance (pConclusion The use of a low COC dose (EE 20 µg/Desogestrel 150 µg) was associated to lower bone mass acquisition in adolescents during the study period.Trial registration: (Register Number):RBR-5 h9b3c
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Odontologia - FOAR