间断低氧对大鼠下丘脑超微结构及前增食欲素水平的影响

目的探讨睡眠中间断低氧对大鼠下丘脑前增食欲素及受体水平的影响以及下丘脑超微结构的变化。方法大鼠分成对照组、间断低氧组和持续低氧组,分别给予吸入空气,持续低氧和间断低氧气体,并在实验开始后1d、3d、1w和4w应用RT-PCR方法测定大鼠下丘脑前增食欲素及受体水平,分析其间的变化关系,电镜观察下丘脑的超微结构变化。结果与对照组和持续低氧组比较,间断低氧4w后大鼠下丘脑前增食欲素mRNA水平明显降低,受体水平升高,但在持续低氧和对照组之间无明显差异。在低氧后1d、3d、7d后大鼠下丘脑前增食欲素mRNA降低,受体水平升高,在4w后,持续低氧组则接近正常。急性持续低氧大鼠超微结构变化更严重,而慢性间断低氧变化更持久。结论慢性间断低氧可以引起下丘脑前增食欲素下降及受体水平升高,急性持续低氧也可引起上述变化,而慢性持续低氧未引起增食欲素改变;慢性间断低氧大鼠下丘脑超微结构表现为严重而持久的变化。     

Effects of continuous and pulsatile PTH treatments on rat bone marrow stromal cells

Bone marrow stromal cells (MSCs) differentiation and proliferation are controlled by numerous growth factors and hormones. Continuous parathyroid hormone (PTH) treatment has been shown to decrease osteoblast differentiation, whereas pulsatile PTH increases osteoblast differentiation. However, the effects of PTH treatments on MSCs have not been investigated. This study showed continuous PTH treatment in the presence of dexamethasone (DEX) promoted osteogenic differentiation of rat MSCs in vitro, as demonstrated by increased alkaline phosphatase (ALP) activity, number of ALP expressing cells, and up-regulation of PTH receptor-1, ALP, and osteocalcin mRNA expressions. In contrast, pulsatile PTH treatment was found to suppress osteogenesis of rat MSCs, possibly by promoting the maintenance of undifferentiated cells. Additionally, the observed effects of PTH were strongly dependent on the presence of DEX. MSC proliferation however was not influenced by PTH independent of treatment regimen and presence or absence of DEX. Furthermore, our work raised the possibility that PTH treatment may modulate stem/progenitor cell activity within MSC cultures.     

Molecular Bases of Caloric Restriction Regulation of Neuronal Synaptic Plasticity

Aging is associated with the decline of cognitive properties. This situation is magnified when neurodegenerative processes associated with aging appear in human patients. Neuronal synaptic plasticity events underlie cognitive properties in the central nervous system. Caloric restriction (CR; either a decrease in food intake or an intermittent fasting diet) can extend life span and increase disease resistance. Recent studies have shown that CR can have profound effects on brain function and vulnerability to injury and disease. Moreover, CR can stimulate the production of new neurons from stem cells (neurogenesis) and can enhance synaptic plasticity, which modulate pain sensation, enhance cognitive function, and may increase the ability of the brain to resist aging. The beneficial effects of CR appear to be the result of a cellular stress response stimulating the production of proteins that enhance neuronal plasticity and resistance to oxidative and metabolic insults; they include neurotrophic factors, neurotransmitter receptors, protein chaperones, and mitochondrial biosynthesis regulators. In this review, we will present and discuss the effect of CR in synaptic processes underlying analgesia and cognitive improvement in healthy, sick, and aging animals. We will also discuss the possible role of mitochondrial biogenesis induced by CR in regulation of neuronal synaptic plasticity.     

Sun exposure and skin cancer,and the puzzle of cutaneous melanoma: A perspective on Fears et al. Mathematical models of age and ultraviolet effects on the incidence of skin cancer among whites in the United States. American Journal of Epidemiology 1977; 105: 420–427

Sunlight has been known as an important cause of skin cancer since around the turn of the 20th Century. A 1977 landmark paper of US scientists Fears, Scotto, and Schneiderman advanced a novel hypothesis whereby cutaneous melanoma was primarily caused by intermittent sun exposure (i.e. periodic, brief episodes of exposure to high-intensity ultraviolet radiation) while the keratinocyte cancers, squamous cell carcinoma and basal cell carcinoma, were primarily caused by progressive accumulation of sun exposure. With respect to cutaneous melanoma, this became known as the intermittent exposure hypothesis. The hypothesis stemmed from analysis of measured ambient ultraviolet radiation and age-specific incidence rates of melanoma and keratinocyte cancers collected as an extension to the US Third National Cancer Survey in several US States. In this perspective paper, we put this novel hypothesis into the context of knowledge at the time, and describe subsequent epidemiological and molecular research into melanoma that elaborated the intermittent exposure hypothesis and ultimately replaced it with a dual pathway hypothesis. Our present understanding is of two distinct biological pathways by which cutaneous melanoma might develop; a nevus prone pathway initiated by early sun exposure and promoted by intermittent sun exposure or possibly host factors; and a chronic sun exposure pathway in sun sensitive people who progressively accumulate sun exposure to the sites of future melanomas.     

间断切口与长切口获取大隐静脉在冠状动脉旁路移植术中作用的对比研究

目的:比较冠状动脉旁路移植术(CABG)中采用间断切口与长切口获取大隐静脉作为静脉桥材料的优缺点。方法:选择2011年12月至2012年12月宁夏医科大学总医院心脏大血管外科111例行CABG的冠状动脉粥样硬化性心脏病患者为研究对象。根据术中获取大隐静脉方法的不同,随机将其分为两组,长切口组64例,在CABG中采用长切口法获取大隐静脉,间断切口组47例,在CABG中采用间断切口法获取大隐静脉。比较两组大隐静脉获取时间、下肢切口缝合时间、下肢手术时间、大隐静脉桥长度、下肢切口长度和下肢切口并发症发生率的差异。结果:间断切口组大隐静脉桥长度及下肢手术时间(45.4±6.7)cm,(65.8±10.3)min与长切口组(47.5±6.7)cm,(65.8±10.3)min比较无统计学差异(P0.05)。间断切口组获取大隐静脉的时间(48.9±8.3)min显著长于长切口组(37.3±5.8)min,下肢切口长度与缝合时间(17.0±3.5)cm,(16.9±3.4)min明显短于长切口组的(43.5±6.4)min,(31.7±5.9)min,差异均有统计学意义(P0.05)。两组大隐静脉壁的损伤情况比较无统计学差异(P0.05),但间断切口组术后下肢切口延迟愈合、感染、渗出、下肢血肿等并发症的发生率低于长切口组(P0.05)。结论:在冠状动脉旁路移植术中,间断切口获取大隐静脉能够显著缩短下肢手术切口长度,有助于减少术后下肢切口感染、延迟愈合、渗出、下肢血肿等并发症的发生。     

OSAHS风险对患者静脉麻醉术后认知功能障碍的影响

目的:探讨OSAHS风险与静脉麻醉手术患者术后发生认知功能障碍的关系。方法:采用No SAS评分对55例静脉麻醉手术患者进行OSAHS风险评估,并将其分为对照组23例(NoSAS 8分)和OSAHS组32例(No SAS≥8分),以蒙特利尔认知评估量表(MoCA)对两组患者在术前和术后第一天进行认知功能评估,计算每位患者手术前后Mo CA评分的差值△Mo CA(术前MoCA-术后MoCA),比较两组患者手术前后的MoCA评分及△MoCA。结果:OSAHS组术前MoCA评分(25.83±1.80)明显低于对照组术前MoCA评分(28.05±1.31)(P0.05)。OSAHS组术后MoCA评分(25.13±1.64)较术前无明显变化(P0.05),对照组术后Mo CA评分(26.73±1.17)明显低于术前(P0.05)。OSAHS组△MoCA(0.39±1.03)明显低于对照组(1.32±1.08),主要表现为视空间与执行功能[(0.09±0.29) vs.(0.30±0.32)]、注意力[(0.09±0.60) vs.(0.47±0.70)]和延时回忆力[(0.17±0.39) vs.(0.47±0.51)]两方面(P0.05)。结论:OSAHS高风险患者静脉麻醉术后认知功能障碍的程度较OSAHS低风险人群显著降低。     

Transgenic rescue of Atg5-null mice from neonatal lethality with neuron-specific expression of ATG5: Systemic analysis of adult Atg5-deficient mice

Atg5-null mice are neonatal lethal. We have revealed in our recent paper that these mice die due to neuronal dysfunction resulting in suckling failure. Our new mouse model, atg5^–/–;Eno2/Nse-Atg5 mice, where Atg5 is deficient in the whole body except for neurons, enables us to analyze the consequences of macroautophagy/autophagy-deficiency in the whole body of adult mice.     

Benthic macrofaunal communities in intermittent estuaries during a drought: Comparisons with permanently open estuaries

Drought conditions have prevailed in many areas of NSW since 2002. On the mid-north coast, below-average rainfall resulted in reduced riverine flows and the extended closure of intermittent estuaries within the Solitary Islands Marine Park. Patterns of structure of benthic infaunal communities were evaluated at the height of the drought to determine if they differed between closed, intermittent estuaries and permanently open estuaries within the region. Replicate van Veen grab samples were taken in the upper, mid- and lower reaches of six intermittent and three permanently open estuaries and sieved to retain the macrofauna. A range of physico-chemical measures was also taken at each sampling time. Multivariate analyses of assemblage data revealed a significant difference between the structure of the two estuary types and also among estuaries within each type. Differences between estuary types were attributable to small differences in the abundance of a number of taxa but also to the absence of the amphipod Urohaustorius metungi from most of the intermittent estuaries. In contrast, these small amphipods dominated communities in the lower reaches of the permanently open estuaries. Physico-chemical variables were highly variable among estuaries and were not strongly correlated with assemblage patterns. Correlations with catchment size were the strongest and, as most of the intermittent estuaries in the region are smaller than the permanently open estuaries, this confounds the interpretation of assemblage patterns in this preliminary study. In order to differentiate between the effects of catchment size and entrance status, the same estuaries need to be resurveyed during periods when at least some of the intermittent estuaries are open.     

Effects of intermittent suckling on body composition of Iberian piglets weaned at 35 days of age

Piglet body composition at weaning could be a determinant for pig’s viability and may be influenced by factors such as the nutritional management followed during suckling. An experiment was conducted to study whether intermittent suckling (IS) affects body composition at weaning and nutrient and energy retention during a 34-day lactation period in Iberian piglets. Litters were subjected to conventional suckling (CS) or IS (n=10 litters of six piglets per treatment) in two trials. All piglets had ad libitum access to creep feed from day 15 onwards. In IS, piglets were progressively separated from the sow for 6, 8 and 10 h daily during the last week of lactation, whereas in CS piglets had continuous access to their dams. Creep feed intake in litters and BW development of individual piglets were measured throughout the 34-day lactation. Within each litter, both at birth and at weaning (day 35), one piglet was used to assess nutrient retention and body composition by the comparative slaughter approach. During days 29 to 35 of the experiment, daily creep feed intake was greater in IS piglets (IS 124, CS 67 g/piglet, P=0.040), and average daily gain differed significantly between groups (IS 190, CS 150 g/day, P=0.010). BW at weaning was higher in the IS than in the CS piglets (IS 8.19, CS 7.48 kg, P=0.011). Empty-body fat and energy content at weaning were higher in the IS compared with CS litters, as well as fat content in the carcass (P=0.04). The IS treatment did not affect empty-body protein deposition, but significantly increased daily retention of fat, energy, ash and calcium, compared with CS litters (P<0.05). Thus, IS in Iberian piglets seems to enhance feed intake, growth rate and retention of some body components, which may contribute to a higher body fat content at weaning and facilitate the weaning process.