494 research outputs found

    Low-density Lipoprotein Cholesterol And Radiotherapy-induced Carotid Atherosclerosis In Subjects With Head And Neck Cancer

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    Background: Radiotherapy (RT) is a risk factor for accelerated carotid artery atherosclerotic disease in subjects with head and neck cancer. However, the risk factors of RT-induced carotid artery remodeling are not established. This study aimed to investigate the effects of RT on carotid and popliteal arteries in subjects with head and neck cancer and to evaluate the relationship between baseline clinical and laboratory features and the progression of RT-induced atherosclerosis.Findings: Eleven men (age = 57.9 ± 6.2years) with head and neck cancer who underwent cervical bilateral irradiation were prospectively examined by clinical and laboratory analysis and by carotid and popliteal ultrasound before and after treatment (mean interval between the end of RT and the post-RT assessment = 181 ± 47 days). No studied subject used hypocholesterolemic medications. Significant increases in carotid intima-media thickness (IMT) (0.95 ± 0.08 vs. 0.87 ± 0.05 mm; p 3.0.CO;2-X, 626923Pereira Lima, M.N., Biolo, A., Foppa, M., da Rosa, P.R., Rohde, L.E., Clausell, N., A prospective, comparative study on the early effects of local and remote radiation therapy on carotid intima-media thickness and vascular cellular adhesion molecule-1 in patients with head and neck and prostate tumors (2011) Radiother Oncol, 101, pp. 449-453. , 10.1016/j.radonc.2010.03.026, 20435360KalĂĄbovĂĄ, H., Melichar, B., Ungermann, L., DoleĆŸal, J., KrčmovĂĄ, L., KaĆĄparovĂĄ, M., PlĂ­ĆĄek, J., SolichovĂĄ, D., Intima-media thickness, myocardial perfusion and laboratory risk factors of atherosclerosis in patients with breast cancer treated with anthracycline-based chemotherapy (2011) Med Oncol, 28, pp. 1281-1287. , 10.1007/s12032-010-9593-1, 20567943Muzaffar, K., Collins, S.L., Labropoulos, N., Baker, W.H., A prospective study of the effects of irradiation on the carotid artery (2000) Laryngoscope, 110, pp. 1811-1814. , 10.1097/00005537-200011000-00007, 11081590Faruolo, M., Fiorentino, A., Gallucci, G., Lapadula, L., Fusco, V., Intimal-medial thickness and carotid arteries lumen in irradiated patients for head and neck cancer: preliminary data of an observational study (2013) Clin Transl Oncol, 15, pp. 861-864. , 10.1007/s12094-013-1023-3, 23463595Ferreira-Sae, M.C., Cipolli, J.A., CornĂ©lio, M.E., Matos-Souza, J.R., Fernandes, M.N., Schreiber, R., Costa, F.O., Nadruz, W., Sodium intake is associated with carotid artery structure alterations and plasma matrix metalloproteinase-9 upregulation in hypertensive adults (2011) J Nutr, 141, pp. 877-882. , 10.3945/jn.110.135921, 21430243Gemignani, T., Azevedo, R.C., Higa, C.M., Coelho, O.R., Matos-Souza, J.R., Nadruz, W., Increased popliteal circumferential wall tension induced by orthostatic body posture is associated with local atherosclerotic plaques (2012) Atherosclerosis, 224, pp. 118-122. , 10.1016/j.atherosclerosis.2012.06.069, 2281862

    Standardization of a method to study angiogenesis in a mouse model

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    In the adult organism, angiogenesis is restricted to a few physiological conditions. On the other hand, uncontrolled angiogenesis have often been associated to angiogenesis-dependent pathologies. A variety of animal models have been described to provide more quantitative analysis of in vivo angiogenesis and to characterize pro- and antiangiogenic molecules. However, it is still necessary to establish a quantitative, reproducible and specific method for studies of angiogenesis factors and inhibitors. This work aimed to standardize a method for the study of angiogenesis and to investigate the effects of thalidomide on angiogenesis. Sponges of 0.5 x 0.5 x 0.5 cm were implanted in the back of mice groups, control and experimental (thalidomide 200 mg/K/day by gavage). After seven days, the sponges were removed. The dosage of hemoglobin in sponge and in circulation was performed and the ratio between the values was tested using nonparametric Mann-Whitney test. Results have shown that sponge-induced angiogenesis quantitated by ratio between hemoglobin content in serum and in sponge is a helpful model for in vivo studies on angiogenesis. Moreover, it was observed that sponge-induced angiogenesis can be suppressed by thalidomide, corroborating to the validity of the standardized method.No adulto, a angiogĂȘnese Ă© restrita a poucas condiçÔes fisiolĂłgicas. Ao contrĂĄrio, a angiogĂȘnese descontrolada frequentemente estĂĄ associada a patologias dependentes de angiogĂȘnese. VĂĄrios modelos animais foram descritos para ajudar na anĂĄlise quantitativa da angiogĂȘnese in vivo e caracterizar molĂ©culas prĂł e antiangiogĂȘnicas. PorĂ©m, ainda Ă© necessĂĄrio estabelecer um mĂ©todo quantitativo, reproduzĂ­vel e especĂ­fico para estudar os fatores prĂł e antiangiogĂȘnicos. Os objetivos deste trabalho foram padronizar um mĂ©todo para estudar angiogĂȘnese e investigar os efeitos da talidomida na angiogĂȘnese. Esponjas de 0,5 x 0,5 x 0,5 cm foram implantadas no dorso de camundongos controles e tratados (talidomida 200 mg/K/dia, por gavagem). ApĂłs sete dias, as esponjas foram retiradas. Avaliou-se a quantidade de hemoglobina na esponja e na circulação. A razĂŁo obtida entre esses valores foi testada por meio do teste nĂŁo paramĂ©trico Mann-Whitney. Os resultados mostraram que a angiogĂȘnese induzida pela esponja e quantificada por meio da razĂŁo hemoglobina esponja/circulação Ă© um modelo Ăștil para estudos in vivo de angiogĂȘnese. AlĂ©m disso, observou-se que a angiogĂȘnese induzida pela esponja diminui na presença de talidomida, corroborando para a validação do mĂ©todo padronizado.Faculdade de Medicina do ABC Departamento de Morfologia e Fisiologia Disciplina de FarmacologiaUniversidade Federal de SĂŁo Paulo (UNIFESP) Quimicas e Farmaceuticas Instituto de Ciencias AmbientaisUNIFESP, Quimicas e Farmaceuticas Instituto de Ciencias AmbientaisSciEL

    IncidĂȘncia do mĂ­ldio em cebola sob adubação mineral e orgĂąnica.

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    Analisou-se a relação entre adubação mineral e orgĂąnica sobre a incidĂȘncia de mĂ­ldio (Peronospora destructor) em cebola (Allium cepa). O trabalho constituiu-se de dois experimentos localizados em Ituporanga, conduzidos entre agosto e dezembro de 1998. O experimento 1, com fontes orgĂąnicas, constou dos tratamentos: esterco de suĂ­nos, esterco de aves, composto, esterco de peru e hĂșmus, na dosagem de 75 kg/ha de N; esterco de suĂ­nos, na dosagem de 37,5 kg/ha de N; adubação mineral, 30-120-60 kg/ha de N-P2O5-K2O; 60-240-120 kg/ha de N-P2O5-K2O e testemunha sem adubação. O experimento 2 constou dos tratamentos: fontes minerais, 30-120-60 kg/ha de N-P2O5-K2O; 90-360-180 kg/ha de N-P2O5-K2O; 75 kg/ha de N; 225 kg/ha de N; 80 kg/ha de P2O5; 240 kg/ha de P2O5; 60 kg/ha de K2O; 180 kg/ha de K2O; esterco de suĂ­nos + fosfato natural, em trĂȘs combinaçÔes, 7,9+0,1, 15,7+0,2 e 47,2+0,6 t/ha, respectivamente; testemunha sem adubação. NĂŁo houve diferença entre as fontes mineral e orgĂąnica sobre a incidĂȘncia de mĂ­ldio. A relação entre nutrientes e doença foi variĂĄvel entre datas de amostragem e distinta para fontes minerais e orgĂąnicas

    Klein tunneling in graphene: optics with massless electrons

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    This article provides a pedagogical review on Klein tunneling in graphene, i.e. the peculiar tunneling properties of two-dimensional massless Dirac electrons. We consider two simple situations in detail: a massless Dirac electron incident either on a potential step or on a potential barrier and use elementary quantum wave mechanics to obtain the transmission probability. We emphasize the connection to related phenomena in optics, such as the Snell-Descartes law of refraction, total internal reflection, Fabry-P\'erot resonances, negative refraction index materials (the so called meta-materials), etc. We also stress that Klein tunneling is not a genuine quantum tunneling effect as it does not necessarily involve passing through a classically forbidden region via evanescent waves. A crucial role in Klein tunneling is played by the conservation of (sublattice) pseudo-spin, which is discussed in detail. A major consequence is the absence of backscattering at normal incidence, of which we give a new shorten proof. The current experimental status is also thoroughly reviewed. The appendix contains the discussion of a one-dimensional toy model that clearly illustrates the difference in Klein tunneling between mono- and bi-layer graphene.Comment: short review article, 18 pages, 14 figures; v3: references added, several figures slightly modifie

    TEMPO NECESSÁRIO PARA NOVILHAS NELORE CRIADAS A PASTO, GANHAREM 210, 240, 270 KG DESDE O NASCIMENTO

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    O objetivo foi avaliar o nĂșmero de dias para novilhas da raça Nelore (4.577) ganharem 210, 240 e 270 kg a partir do nascimento, criadas em regime de pasto. Para as anĂĄlises estatĂ­sticas, utilizou-se o mĂ©todo dos quadrados mĂ­nimos. O modelo continha os efeitos fixos de mĂȘs e ano de nascimento da novilha e a idade da mĂŁe como covariĂĄvel; como efeito aleatĂłrio, touro aninhado dentro de fazenda e o erro. As respostas mostraram que Ă© possĂ­vel desafiar fĂȘmeas mais jovens, com pesos menores, quando lhes sĂŁo asseguradas boas condiçÔes nutricionais, e assim permitir que seu crescimento nĂŁo seja interrompido. Days from birth to get 210, 240, 270 kg for nellore heifers on grazing Abstract The objective of this study was to evaluate the number of days for 4,577 nellore heifers raised in regimen of grass to get 210, 240 and 270 kg of weight since the birth. For statistical analyses, the square means method was used. The model contained the fixed effects from helferÂŽs month and year of birth and the damÂŽs age as co-variable; as random effect, bull sheltered inside the farm and the error. The results showed that it is possible to challenge younger females, with lower weight, when good nutritional conditions are assured, allowing uninterrupted growth
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