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881.
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Purpose
To investigate skin penetration of poly (amidoamine) (PAMAM) dendrimers as a function of surface charge and molecular weight in presence and absence of iontophoresis. 相似文献884.
The multiple intestinal neoplasia (Min) mice have a mutation in the murine
adenomatous polyposis coli (Apc) gene rendering them highly susceptible to
spontaneous intestinal adenoma formation, similar to the familial
adenomatous polyposis (FAP) syndrome in humans. We studied whether the most
abundant mutagenic heterocyclic amine isolated from cooked food,
2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), could influence
early intestinal neoplasia in C57BL/6J-Min/+ and C57BL/6J- +/+ (wild-type)
mice of both sexes. PhIP was given in 4 weekly i.p. injections of 50 mg/kg.
Ten weeks after the start of the experiment, PhIP had significantly
increased the numbers of small tumors and cystic crypts in the proximal
section of the small intestine in male Min/+ mice, and the numbers of
aberrant crypt foci (ACF) in the large intestines of both males and
females. The effects of PhIP were more pronounced in male than in female
Min/+ mice. In +/+ mice, no tumors or cystic crypts in the small intestine,
and no tumors and only a very few ACF in the large intestine, were induced
by PhIP. These results show that a substance frequently present in the
human diet is able to enhance the neoplastic process induced by a genetic
lesion, which is also commonly found both in inherited and sporadic colon
carcinomas in humans.
相似文献
885.
Wang C Nieschlage E Swerdloff R Behre HM Hellstrom WJ Gooren LJ Kaufman JM Legros JJ Lunenfeld B Morales A Morley JE Schulman C Thompson IM Weidner W Wu FCW 伍学焱 《国际生殖健康/计划生育杂志》2011,30(1):29-32,41
简介
人口学资料明确显示:老年人口占总人口的百分率正逐年增加.当前,有关老年男性雄激素缺乏的问题逐渐成为令人感兴趣、但又充满争议的世界性话题.已经有横向和纵向的研究资料表明,随着年龄增大,成年男子的雄激素水平逐渐降低,且相当一部分年龄超过60岁男性的血清睾酮水平已降到正常年轻成年男性(20~30岁)的低限值以下. 相似文献
886.
887.
888.
Joanne L. Harrison Cara M. Hildreth Stephen M. Callahan Ann K. Goodchild Jacqueline K. Phillips 《Autonomic neuroscience : basic & clinical》2010,152(1-2):60-66
Autonomic dysfunction, hypertension and cardiovascular morbidity in end stage renal disease are critically linked, however there are limited models available to investigate this relationship and develop clinical interventions. This study aimed to define the relationship between hypertension and autonomic function in a new rodent model of polycystic kidney disease (PKD). Using measures of heart rate and systolic blood pressure variability (HRV, SBPV), and time domain analysis of cardiac and sympathetic baroreflex function, we compared the Lewis PKD model (LPK) to a Lewis control. Systolic BP and SBPV were significantly higher in LPK vs. Lewis (168 ± 7 vs. 131 ± 8 mm Hg, P ≤ 0.01, total power: 11 ± 3.1 vs. 1.3 ± 0.3 mm Hg/Hz2, P ≤ 0.05). LPK has a higher resting HR (437 ± 17 vs. 330 ± 11 beats per minute [bpm], P ≤ 0.001) associated with reduced HRV (total power [1.7 ± 0.3 vs. 4.6 ± 1.1 ms/Hz2, P ≤ 0.01]). Atenolol decreased HR to a greater extent in the LPK (90 ± 10 vs. 20 ± 17 bpm, P ≤ 0.001) while subsequent methylatropine administration produced a greater increase in Lewis HR (24 ± 9 vs. 66 ± 9 bpm, P ≤ 0.01). No difference in intrinsic HR following both drugs existed. Cardiac baroreflex function was impaired in LPK vs. Lewis (0.6 ± 0.4 vs. 1.2 ± 0.2 bpm/mm Hg P ≤ 0.05, and 0.3 ± 0.1 vs. 3.1 ± 0.6 ms/mm Hg, P ≤ 0.001, respectively). The sympathetic baroreflex function curve was shifted upwards and towards the right in LPK (P ≤ 0.01). Sympathetic baroreflex gain was not altered. This data suggests that sympathetic hyperactivity and reduced vagal function underlies the hypertension and reduced cardiac baroreflex function in the LPK model. 相似文献
889.
To estimate fetal absorbed dose from radiographic examinations, the depth from the anterior maternal surface to the midline of the fetal skull and abdomen was measured by ultrasound in 97 pregnant women. The relationships between fetal depth, fetal presentation, and maternal parameters of height, weight, anteroposterior (AP) thickness, gestational age, placental location, and bladder volume were analyzed. Maternal AP thickness (MAP) can be estimated from gestational age, maternal height, and maternal weight. Fetal midskull and abdominal depths were nearly equal. Fetal depth normalized to MAP was independent or nearly independent of maternal parameters and fetal presentation. These data enable a reasonable estimation of absorbed dose to fetal brain, abdomen, and whole body. 相似文献
890.