血管性认知功能障碍的研究进展

血管性认知功能障碍(VCI)是目前严重危害老年人健康的疾病之一。随着人类寿命的延长、人口老龄化的增加,将会有越来越多的老年人患者患上VCI。对于VCI的早期、有效的干预有重要的临床意义,也受到人们的广泛关注。如能预防甚至治疗VCI的产生,可从很大程度上提高老年人的生活质量,减轻家庭和社会的负担。现就近年来对血管性认知功能障碍的相关研究予以综述。     

时间认知的年老化及其神经机制

时间认知功能的增龄性衰退表现得较晚,主要在高龄老年人中表现出时间认知功能的衰退.随着年龄的增长,老年人内部时钟的速率变慢,变异增大.注意及记忆功能随年龄增长而衰退,这些一般认知功能的改变影响老年人的时间认知功能.正常的时间认知功能依赖于"核心-背景"时间加工脑网络结构和功能的完好,这些脑区或功能通路的障碍会导致时间认知功能的损伤.老年人在一定的年龄范围内,可以通过认知补偿策略保持相对完好的时间认知功能.     

老年人认知训练的神经机制研究

伴随老化,老年人的认知和脑功能会表现出一定的下降趋势.尽管如此,人类的大脑到老年期都会保有一定的可塑性,认知训练的方式是延缓认知和脑功能衰退的有效手段.本文回顾了以往针对老年人不同类型的认知训练研究,探讨了认知训练的理论基础(包括放大观和补偿观),深入分析了老年人认知训练的神经机制,并在此基础上指出以往研究中理论基础冲突的不足和对未来研究老年人训练任务适配性的展望.     

肠道菌群与老年认知障碍的研究进展

认知减退是脑老化的一个重要特征,随着年龄的增长,炎症反应增加、抗氧化能力下降、血脑屏障损伤及海马结构变化都与老年人认知功能减退有关。近年来,越来越多的研究发现伴随年龄增长而发生的肠道微生物组成变化也是影响老年认知功能的重要原因,并逐渐成为老年认知障碍的重要研究靶点。大量研究发现,肠道菌群可经肠脑轴对老年认知功能产生影响,不仅可以通过神经递质、迷走神经、神经内分泌、免疫调节等途径影响大脑记忆、情感及其他认知领域的功能,还可以通过影响β-淀粉样蛋白沉积、脂多糖水平及小胶质细胞的发育与成熟影响认知功能。本文综述了近年来有关肠道菌群和老年认知功能障碍的相关进展,以期为老年认知障碍相关疾病的防治与康复提供新的思路。     

轻度认知障碍的研究进展

老年性痴呆(阿尔茨海默病,Alzheimer disease,AD)是目前严重影响老年人生存质量的疾病,且疗效不佳。据推测到2050年阿尔茨海默病的患病率将是现今的三倍。轻度认知障碍(mild cognitive impairment,MCI)是介于阿尔茨海默病和正常衰老之间的一种认知功能损害状态,是发生阿尔茨海默病的高危因素。文献报道轻度认知障碍每年以8%-25%的比例进展为阿尔茨海默病,较正常人群阿尔茨海默病发病率高10倍。与阿尔茨海默病病理损害不可逆相比,轻度认知障碍患者通过早期干预治疗,可延缓或阻止病情发展为阿尔茨海默病。因此,对阿尔茨海默病早期出现的轻度认知功能障碍诊断及干预尤为重要。本文就认知功能早期阶段,轻度认知功能障碍的历年(2000年到2014年3月)研究进展从概念及分型、临床表现、诊断标准、病理生理及其影像学研究、危险因素及其预防、干预措施(药物和非药物)等方面的最新进展进行论述。     

体育锻炼与心理健康:认知、焦虑、抑郁和自我概念的研究进展

体育锻炼对心理健康的影响主要研究成果集中在认知功能,焦虑和抑郁,以及自我概念。体育锻炼可以有助于认知功能的提高,减少老年人的认知退化以及改善智力落后儿童的认知能力。体育锻炼可以作为焦虑和抑郁的预防和治疗的手段之一。体育锻炼也可以提高自我概念,有助于良好心理品质的形成。本文对以上三个方面的研究进行综述,并提出研究中的困难和今后研究的展望。     

城乡老年人营养状况与认知功能的相关性研究

目的：调查城乡老年人营养状况及认知功能状况,探讨两者的相关性。方法：采用多层次随机抽样法,抽取某地65岁及以上城乡居民1 246人进行调查,采用微型营养评价量表（MNA-SF）评价营养状况、采用简易智能精神状态检查量表（MMSE）评价认知功能,采用多因素Logistic回归分析营养状况与认知功能关系。结果：调查对象中121人（9.7%）有营养不良风险或营养不良,450人（36.1%）有不同程度的认知功能障碍。城乡营养不良的老年人认知功能障碍率高于其营养正常的老年人,差异具有统计学意义（P＜0.05）。多因素分析显示,居住地在农村、教育程度低、营养不良、未规律运动是老年人认知功能障碍的危险因素（P＜0.05）。结论：老年人营养状况与认知功能相关,且存在城乡差异。加强营养支持改善营养状况对提高老年人认知功能,实现成功老龄化有着积极的作用。     

全身麻醉药物对术后认知功能的影响及可能机制的研究进展

术后认知功能障碍(postoperative cognitive dysfunction,POCD)是一种常见的术后并发症,好发于老年人。但其发病机制至今未能完全阐明,因此临床上缺少针对性的防治措施。近几年研究发现,麻醉药物是引起患者认知功能下降的重要原因之一。本文就全身麻醉药物对术后认知功能的影响及发生认知功能障碍的可能机制作论述,以期为POCD的防治提供新思路。     

老年人饮食摄入对认知功能障碍影响的研究进展

膳食摄入与老年人认知功能障碍的发生关系密切,本文就饮食及营养状况与老年人认知功能障碍关联的研究进行综述,以期为改善认知障碍老年患者的生活质量和构建更符合中国居民生活习惯的精细化饮食健康管理计划提供依据。     

国内7省市老年人抑郁症的检出率及影响因素分析

目的:调查分析国内7省市老年人抑郁症的检出率及特点,并从老年人基本情况、躯体健康、认知功能等方面综合分析抑郁症的影响因素。方法:采用GDS-30量表分析2011-2012年在北京、上海、哈尔滨、西安、成都、长沙和重庆市及周边乡镇的9200名60岁以上老年抑郁症的发生情况,并分析影响抑郁检出率的相关因素。结果:调查老年对象的抑郁症检出率为17.2%,其中男性为15%,女性为19.6%。女性老年人在各个年龄段的抑郁症检出率均高于男性。抑郁症检出率随着年龄的增加逐渐增加。文化水平、健康自评、认知功能与抑郁症检出率密切相关。结论:抑郁症是国内7省市老年人常见的心理疾病,女性、高龄、低文化水平、健康自评差、认知功能障碍的老年人患抑郁症的几率更高。     

Ectogenesis and the case against the right to the death of the foetus

Ectogenesis, or the use of an artificial womb to allow a foetus to develop, will likely become a reality within a few decades, and could significantly affect the abortion debate. We first examine the implications for Judith Jarvis Thomson’s violinist analogy, which argues for a woman’s right to withdraw life support from the foetus and so terminate her pregnancy, even if the foetus is granted full moral status. We show that on Thomson’s reasoning, there is no right to the death of the foetus, and abortion is not permissible if ectogenesis is available, provided it is safe and inexpensive. This raises the question of whether there are persuasive reasons for the right to the death of the foetus that could be exercised in the context of ectogenesis. Eric Mathison and Jeremy Davis have examined several arguments for this right, doubting that it exists, while Joona Räsänen has recently criticized their reasoning. We respond to Räsänen’s analysis, concluding that his arguments are unsuccessful, and that there is no right to the death of the foetus in these circumstances.     

On the diversity of the Cladocera in the tropics

The mythical concept of an impoverished tropical cladoceran fauna is refuted. On a planetary scale, around half of the cladoceran species presently known occur exclusively in the tropics-subtropics, often with considerable restriction to particular geographical subzones. On a regional (political) scale, the situation is often unclear because of the continued fragmentary nature of studies, and because political units are not a good basis for biogeographical comparisons. At the finest level of resolution (lake-perlake comparisons), there appears to be an upper limit of c. 50 cladoceran species per individual lake. No significant difference between lakes in the temperate zone and in the tropics could be established here. Daphnia is largely absent from the tropics, but is replaced by more Sidids, Moinids, and Bosminids, such that the average cladoceran community in the limnetic zone of a tropical lake is not characterized by less species but rather by lower population densities. This, in turn, is considered a consequence of higher prevalent predation levels in the tropics.     

Tubular networks in the terminal endings of the visual receptor cells in the human,the monkey,the cat and the dog

Summary A tubular network was found in the terminal endings of the visual receptor cells in the human, the monkey (Macaca mulatta), the cat and the dog. These tubules are arranged in close groups in the vicinity of the synaptic lamellae and the invaginated dendrites. According to the form, diameter, density of the tubules and to the consistence of the network formed by them one can distinguish at these places an initial type (type I), a transitory (type II) and a vesicular one (type III). In the the type III branching, bizarre forms are frequent. The diameter of all the tubules reaches 500–600 Å, their density and walls being the same as in the synaptic vesicles.Similar networks also occur in the axons of the visual receptor cells of the monkey.

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Zusammenfassung In den Endigungen der Photorezeptorzellen von Mensch, Affe (Macaca mulatta), Katze und Hund kommen aus Tubuli bestehende Komplexe vor. Organellenartig in geschlossenen Gruppen angeordnet, liegen sie in Nähe der synaptischen Lamellen und der invaginierten Dendriten. An diesen Stellen kann man nach Form, Durchmesser, Dichte und Konsistenz der von den Tubuli gebildeten Komplexe drei Typen unterscheiden: 1. einen initialen (Typus I), 2. einen Übergangstypus (Typus II) und 3. einen vesiculären Typus (Typus III). In letzterem kommen häufig verzweigte, bizarre Formen vor. Der Durchmesser sämtlicher Tubuli erreicht 500–600 Å. Ihre Dichte und ihre Wand gleicht denen der synaptischen Vesikel.Ähnliche Komplexe fanden wir auch in den Axonen der Photorezeptorzellen vom Affen.

     

Assessing the Physiological State of the Fucoids from the Barents Sea Littoral by the End of the Polar Night

Methods of amperometry and potentiometric titration were used to follow dark respiration (DR) and apparent photosynthesis (AP) in the fucoids Ascophyllum nodosum (L.) Le Jol, Fucus vesiculosus L., and F. serratus L. from the Barents Sea littoral by the end of the 40-day-long polar night. The macroalgae were shown to manifest species-specific low rates of photosynthesis and respiration. However, in spite of their low photosynthetic status due to the effects of subzero temperature and prolonged low or zero illumination, the macroalgae have been able to restore DR and AP to the initial level already by the day 9; the ability to restore AP depended on the level of illumination. The study of the changes in the carbonate–bicarbonate system in the light and darkness demonstrated that the macroalgae grown in darkness, in contrast to those grown in twilight, could absorb bicarbonate in darkness; however, they lost this capacity after two-day-long illumination at an irradiance of 7 mol/(m² s). Bicarbonate uptake in darkness and the capacity to restore the systems of photosynthesis and respiration in fucoid cells are discussed in the context of algal energy metabolism under the polar night conditions.     

Arranging the elements of the potassium channel: the T1 domain occludes the cytoplasmic face of the channel

The voltage-gated potassium channel is currently one of the few membrane proteins where functional roles have been mapped onto specific segments of sequence. Although high-resolution structures of the transmembrane portions of three bacterial potassium channels, the tetramerization domain and the cytoplasmic ball are available, their relative spatial arrangement in mammalian channels remains a matter of ongoing debate. Cryo-electron microscopic images of the six transmembrane voltage-gated Kv channel have been reconstructed at up to 18 Å resolution, revealing that the T1 domain tetramerizes and is suspended below the transmembrane segments. However, the resolution of these images is insufficient to reveal the location of the third piece of the puzzle, the inactivating ball domain. We have used the aberrant interactions observed in a series of chimæric channels to establish that an assembled T1 domain restricts access to the cytoplasmic face of the channel, suggesting that the N-terminal ball and chain may be confined in the space between the T1 domain and the transmembrane portion of the channel.     

Feeding the vertebrate retina from the Cambrian to the Tertiary

The retina of the vertebrate eye is metabolically active and requires nutritive support. During the last 540 million years it has evolved into forms as complicated and nutritionally demanding as those found in avian or primate eyes. Diffusion from the choroid is generally able to supply the metabolic needs of thin retinae. However, when the thickness exceeds the limits of diffusion, structures are needed to supplement the vascular supply from the choroid. These supplemental nutritive devices include the choroidal gland, the falciform process and preretinal vascular plexus of fish, the conus papillaris of lizards, the pecten oculi of birds, the intraretinal vessels of mammals and a few novel systems that remain difficult to classify. These vascular systems are among the most variable features of the vertebrate eye. Here, we review classical and recent findings regarding such retinal nutrition systems, propose a three category classification for them based on histologic origins and speculate on the evolutionary forces which drove their development.     

Separation of the pineal vesicle from the wall of the third ventricle during the post-hatching development of the chicken

Summary According to light- and electron-microscopic observations the pineal organ of the 3-day-old chicken consists of a prominent end vesicle and a tapering parenchymal stalk. During this stage the pineal lumen is in open communication with the third ventricle. However, in the 40-day-old chicken, which still possesses a well-developed end vesicle, the proximal portion of the pineal stalk displays regressive changes leading to local fragmentation. At this stage the pineal stalk is reduced, and the pineal lumen is missing. In 1-year-old chickens the parenchyma of the proximal portion of the stalk is further diminished, and in 3-year-old domestic fowl is completely displaced by bundles of collagenous fibers, only some nerve fibers being present. This post-hatching pineal development may reflect the sequence of changes leading from pineal sense organs to pineal glands.This work was supported by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan     

Observations on the permeability of the choriocapillaris of the eye

Summary The choriocapillaris is a fenestrated capillary bed located posterior to the retinal pigment epithelium. It serves as the main source of supply to the photoreceptors, retinal pigment epithelium, and other cells of the outer retina. The permeability of these capillaries to intravenously injected ferritin (MW — approx. 480,000; mol. diam. 11 nm) was examined in the mouse, rabbit, and guinea pig, each of which is characterized by a different type of retinal vascularization. In all three species, the bulk of the ferritin remained in the capillary lumina, where it appeared to be blocked at the level of the diaphragmed fenestrae. Some ferritin was present in endothelial cell vacuoles. The results confirm previous work on the rat choriocapillaris and indicate that the barrier function of the choriocapillary endothelium is present even among species in which the retinal circulation differs significantly.Supported by NIH grant EY03418