妇女叶酸增补中需要关注的问题

妇女围孕期增补叶酸能够有效预防神经管缺陷等疾病的发生。随着对叶酸研究的不断深入，叶酸补充中出现了诸多问题。本文简要综述了叶酸在服用方式以及基础和临床研究中出现的值得讨论、已经引起关注和需要进一步研究探讨的问题，并提出了深入研究叶酸可能的发展趋势。     

耗竭-补充营养素对初断乳大鼠进食量及体重的影响

目的：观察锌(Zn)、维生素A(VA)、维生素B2(VB2)缺乏和补充对初断乳大鼠进食量、体重的影响。方法：通过耗竭一补充方式造成初断乳大鼠的Zn、VA、VB2单独和联合缺乏模型，后强化补充相应营养素，动态检测大鼠进食量、体重的变化。结果：Zn、VA、VB2缺乏时不同程度地影响大鼠进食量、体重，以联合缺乏影响最为突出；强化补充相应营养素后，大鼠进食量、体重均得到改善，但仍达不到正常发育水平。结论：婴幼期Zn、VA、VB2缺乏或不足可影响生长发育，应充分重视婴幼儿营养。     

Neuroendocrine factors regulating blood glucose, plasma FFA and insulin in the development of obesity

A number of neurotransmitters and neuropeptides in the hypothalamus play a role in the control of food intake, metabolism, and body weight. Particularly, noradrenergic mechanisms in several areas of the hypothalamus are involved. Control of peripheral metabolism by the hypothalamus is achieved via autonomic modulation of the function of hepatocytes, adipocytes, and the endocrine cells in the islets of Langerhans. The autonomic control mechanisms ultimately lead to an appropriate shaping of blood glucose, plasma FFA, and insulin profiles to guarantee an adequate flow of nutrients under different physiological situations. Peripheral insulin and glucose can penetrate into the brain where they might affect the function of those brain structures involved in control of food intake, metabolism, and body weight.     

The aging process and potential interventions to extend life expectancy

Aging is commonly defined as the accumulation of diverse deleterious changes occurring in cells and tissues with advancing age that are responsible for the increased risk of disease and death. The major theories of aging are all specific of a particular cause of aging, providing useful and important insights for the understanding of age-related physiological changes. However, a global view of them is needed when debating of a process which is still obscure in some of its aspects. In this context, the search for a single cause of aging has recently been replaced by the view of aging as an extremely complex, multifactorial process. Therefore, the different theories of aging should not be considered as mutually exclusive, but complementary of others in the explanation of some or all the features of the normal aging process. To date, no convincing evidence showing the administration of existing “anti-aging” remedies can slow aging or increase longevity in humans is available. Nevertheless, several studies on animal models have shown that aging rates and life expectancy can be modified. The present review provides an overlook of the most commonly accepted theories of aging, providing current evidence of those interventions aimed at modifying the aging process.     

食品添加剂KAl（SO4）2中Al的吸收,排泄,蓄积实验研究

目的：探讨我国主要含铝食品添加剂——硫酸铝钾中铝的吸收、排泄和贮留的基本情况。方法：１．采用６月龄日本雄性大耳兔８只进行３天的代谢平衡实验。２．选用２～３月龄２１只雄性兔进行３２周的蓄积实验。结果：代谢实验表明铝的表观吸收率平均在１０％左右，约９０％的口服铝在粪中排出。尿铝随摄入铝的增加而增加，但肾排铝能力不足吸收的１０％。兔的蓄积实验证明在３２周实验后实验兔随铝摄入的增加其主要脏器均有不同程度的铝蓄积。其蓄积量的顺序为：骨＞肝＞肾＞脑＞心（３．８９～１０５．４６ｍｇ／ｋｇ干重）；蓄积增长倍数为：肝＞脑＞肾＞骨＞心（１．５１～４．５８倍）。结论：１．食品添加剂硫酸铝钾中铝的表观吸收率平均在１０％左右。尿铝随摄入铝的增加而增加，但肾排铝量不足吸收的１０％。２．长期大量摄入含铝食品添加剂可导致机体铝蓄积，其中脑、骨、肝、肾蓄积较明显。     

Brainstem mediates diazepam enhancement of palatability and feeding: microinjections into fourth ventricle versus lateral ventricle

The hypothesis that benzodiazepine-induced hyperphagia is due to a specific enhancement of the palatability of foods has been supported by previous ‘taste reactivity’ studies of affective (hedonic and aversive) reactions to taste palatability. Diazepam and chlordiazepoxide enhance hedonic reactions of rats (rhythmic tongue protrusions, etc.) to sweet tastes in a receptor-specific fashion. A role for brainstem circuits has been indicated by a previous demonstration of the persistence of the taste reactivity enhancement by diazepam after midbrain decerebration. The present study examined whether benzodiazepine brainstem receptors are the chief substrates for palatability enhancement even in intact brains. We compared the effectiveness of benzodiazepine microinjections to elicit feeding and enhance hedonic reactions when delivered into either the lateral ventricle (forebrain) or the fourth ventricle (brainstem) of rats. The results show diazepam is reliably more effective at eliciting feeding and enhancing positive hedonic reactions to oral sucrose when microinjections are made in the fourth ventricle than in the lateral ventricle. We conclude that brainstem neural systems containing benzodiazepine-GABA receptors are likely to be the chief substrates for benzodiazepine-induced palatability enhancement.     

An estimate of phylogenetic relationships among culicine mosquitoes using a restriction map of the rDNA cistron

Restriction maps of the rDNA cistron of twelve species of mosquitoes in six genera of the subfamily Culicinae were constructed using eight 6 bp recognition restriction enzymes. Anopheles albimanus was used as an outgroup. The size of the rDNA cistron ranged from 8.5 kb in Aedes katherinensis to 12.9 kb in Ae. polynesiensis. A total of twenty-six sites were scored; eighteen were polymorphic among ingroup taxa. The proportion of polymorphic nucleotide sites (Pnuc) was 0.059 and the heterozygosity per nucleotide site (Hnuc) was 0.028. Wagner and Fitch Parsimony, Dollo Parsimony and Nei-Li distance/neighbour-joining methods were used to construct phylogenetic trees. The rDNA RFLP dataset did not provide a well-supported phylogeny among culicine taxa. The RFLP phylogenies are incongruent with the morphology character based and molecular phylogenies and derived relationships did not correspond with current taxonomic classifications. The lack of resolution was due to homoplasy arising from frequent independent loss or gain of restriction sites among unrelated taxa.     

RENIN GENE POLYMORPHISM ASSOCIATED WITH ALDOSTERONE RESPONSIVENESS TO THE RENINANGIOTENSIN SYSTEM IN PATIENTS WITH ALDOSTERONE-PRODUCING ADENOMAS

1. Aldosterone levels in patients with unilateral aldosterone-producing adenomas may be responsive or unresponsive to the renin-angiotensin system, with the former often previously misdiagnosed as bilateral adrenal hyperplasia. 2. In tumours from patients in the responsive subgroup, renin mRNA is expressed in greater amounts than in tumours from patients in the unresponsive subgroup, or in normal adrenals. 3. We compared the frequency of four renin gene polymorphisms in peripheral blood DNA from the two subgroups and found significant associations between BglI, TaqI and HinfI restriction fragment length polymorphisms (RFLP) and aldosterone responsiveness. 4. Allelic variation in the constitutive renin gene was associated with a specific cause of hypertension.     

中国汉族群体D4S111位点的遗传多态性研究

目的：研究中国汉族群体中α艾杜糖苷酶基因Ｄ４Ｓ１１１位点的遗传多态性。方法：采用扩增片段长度多态性（ＡｍｐＦＬＰ）分析技术，检测了广州地区汉族无血缘关系健康个体９７名。结果：Ｄ４Ｓ１１１位点，在９７名无关个体中发现５个等位基因和９种基因型，等位基因片段长度为８３０～５１０ｂｐ，基因频率为０００５２～０３６０８，ＰＩＣ为０５９６６，杂合性为０７８。结论：中国汉族群体中Ｄ４Ｓ１１１位点具有高度多态性，并与其它种族间存在差异性。