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排序方式: 共有47条查询结果,搜索用时 15 毫秒
1.
Considerable scientific evidence demonstrates the reduction in risk for neural tube defects (NTDs) associated with maternal preconceptional folic acid supplementation. The National Society of Genetic Counselors (NSGC) endorses the U.S. Public Health Service recommendations for folic acid supplementation at the 0.4 mg level for women in the general population and at the 4.0 mg level for women at high or increased risk for NTD pregnancies for at least 4 weeks prior to active pursuit of conception. We encourage targeted educational efforts and surveillance to assess results of this dietary supplementation. The NSGC further urges the Food and Drug Administration to fortify staple foodstuffs with folic acid for a population-based approach to minimize the number of NTD births.  相似文献   
2.
5-Hydroxytrypotophan at a dose of 50 mg/kg intraperitoneally (i.p.) sharply increased neural serotonin (5-HT) levels in mink and considerably inhibited that animal's predatory attack on rats. Intraperitoneal injection of 5-HT (10 and 20 mg/kg) did not influence such rat-killing. Neural levels of 5-HT or 5-hydroxyindoleacetic acid (5-HIAA) and subsequent aggression by the predator did not change to any great degree after ingestion of a single meal. Abundance of natural mink food for 3 days was associated with an increased level of 5-HIAA in the lateral hypothalamus and the amygdala as well as with an increased latency to attack and to kill rats. 5-HT seems to represent an endogenous factor that inhibits predatory attack by the mink; this effect appears to function through increased metabolism of 5-HT in some brain regions, which is evident after abundant intake of tryptophan with the natural diet.  相似文献   
3.
To understand the neural basis of human speech control, extensive research has been done using a variety of methodologies in a range of experimental models. Nevertheless, several critical questions about learned vocal motor control still remain open. One of them is the mechanism(s) by which neurotransmitters, such as dopamine, modulate speech and song production. In this review, we bring together the two fields of investigations of dopamine action on voice control in humans and songbirds, who share similar behavioral and neural mechanisms for speech and song production. While human studies investigating the role of dopamine in speech control are limited to reports in neurological patients, research on dopaminergic modulation of bird song control has recently expanded our views on how this system might be organized. We discuss the parallels between bird song and human speech from the perspective of dopaminergic control as well as outline important differences between these species.  相似文献   
4.
尽管30年前鲍林与卡梅伦曾经用静脉注射+口服大剂量维生素C(10克/天)治疗肿瘤患者,并验证抗坏血酸的抗癌功效,但梅约医疗中心的口服双盲试验否定了他们的结论.沉寂30年后,鲍林的继承者瑞欧丹通过不懈的努力用科学实验和医疗实践证明,通过静脉滴注大剂量抗坏血酸,令其在血浆达到一定浓度,可以杀死多种癌细胞,从而作为化疗药物可以有效治疗恶性肿瘤.30年来的临床实践现已总结为“瑞欧丹规程”.近年来,他们的成就受到美国主流医学和媒体的高度重视.与一般化疗药物相比,该法的好处是基本没有副作用,延长生存期,提高存活质量(QOF).这是一项重大科学发现和成就.该疗法的确立意义重大,将推动癌的治疗及预防,乃至其他疾病如冠心病、感染性疾病及炎症的治疗及预防,提高人类健康水平.  相似文献   
5.
In an attempt to control gastric acid secretion with operant-conditioning techniques, four normal women were given visual feedback on gastric pH plus money reinforcers. When money was made dependent on increased secretion in a differential-reinforcement-of-high-rates schedule, the rate of secretion of three of the four subjects increased to three times baseline. When money was then made dependent on decreased secretion in a differential-reinforcement-of-other-behaviors schedule, the rate of secretion of these three subjects returned to baseline levels. Heart rate, respiratory frequency, abdominal electromyographic activity, and stomach motility (measured by the electrogastrogram method) were not consistently correlated with acid secretion across subjects, although individual subjects showed substantial correlations between acid secretion and one or more other physiological response.  相似文献   
6.
继发性高血压病因的检出和针对病因的治疗,不仅可以提高高血压的治愈率和控制率,有利于保护靶器官,还可以极大程度地减少医疗资源的浪费。基本的临床检查,如血、尿常规,血浆电解质,血糖,血脂,血尿酸和血清肌酐,可以为继发性高血压的诊断提供重要的线索。  相似文献   
7.
探讨丙戊酸是否增强COC1/DDP对顺铂的敏感性并初步探讨其机制。采用WST-1、流式细胞术、免疫细胞化学法。结果丙戊酸与顺铂联合对细胞生长抑制和凋亡诱导明显强于顺铂组;NF-κB P65的表达量顺铂组高于对照组,联合组明显低于顺铂组。因此,丙戊酸增强COC1/DDP对顺铂的敏感性,且与NF-κB有关。  相似文献   
8.
Arthur Peacocke was one of the most important scholars to contribute to the modern dialogue on science and religion, and for this he is remembered in the science‐religion community. Many people, however, are unaware of his exceptional career as a biochemist prior to his decision to pursue a life working as a clergyman in the Church of England. His contributions to studies of deoxyribonucleic acid (DNA) structure, effects of radiation damage on DNA, and on the interactions of DNA and proteins are among the most important in the field at the time and have had a lasting scientific impact that is still felt today. Peacocke's arguments with Jacques Monod over stochastic (chance) and deterministic (necessity) processes driving evolution became important independently for both the science and the religion communities and appear to have contributed significantly to his decision to become involved in science‐religion dialogue rather than continuing his work exclusively in the field of science. Nevertheless, although Peacocke took on an active church life and ceased his experimental work, he never left science but continued to read the scientific literature and published a scientific review on different approaches in defining DNA structure as recently as 2005.  相似文献   
9.
神经管缺陷(NTDS)是一种常见的先天性中枢神经系统畸形,其发生率占据我国出生缺陷的前列。本文从其发病原因、产前诊断及预防措施进行系统分析,希望能找出一条降低其发生率的有效途径,从而进一步提高我国的人口素质。  相似文献   
10.
免疫分析中抗体干扰相关问题的探讨   总被引:1,自引:0,他引:1  
免疫分析是一项应用广泛的技术,抗体是免疫分析的关键问题。循环中内源性抗体对免疫分析的干扰与该技术本身一样古老,由于抗体干扰造成的可疑或错误的结果一直与其并存。但对于其机制、类型扣对策并未廓清。有鉴于此,有必要对抗体干扰免疫分析的诸多问题进行更深入的基础与临床研究,以提高临床诊断水平。  相似文献   
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