条件性敲除胰岛β细胞蛋白磷酸酶2Acα对小鼠糖代谢影响机制的探讨

目的探讨条件性敲除胰岛β细胞蛋白磷酸酶2Acα(PP2Acα)对小鼠血糖水平影响的机制。方法选取4月龄条件性敲除胰岛β细胞PP2Acα(KO组)及对照组(Con,与KO组同窝别、性别匹配)各24只。行腹腔葡萄糖耐量实验(IPGTT),测定0、30、60和120min小鼠血糖及胰岛素分泌水平;新鲜分离胰岛,用葡萄糖刺激胰岛素分泌实验(GSIS)评价小鼠胰岛β细胞对葡萄糖反应性。结果IPGTT结果显示,KO组葡萄糖负荷后30min血糖[(23.1±5.1)vs(17.5±5.7)mmol/L]和60min血糖[(20.5±6.8)vs(13.5±5.1)mmol/L]高于Con组(P0.05);KO组葡萄糖负荷后30min血清胰岛素水平较Con组下降[(2.16±0.92)vs(1.07±0.42)μg/L](P0.05);GSIS显示高糖刺激下KO组胰岛素分泌较Con组减少[(0.82±0.15)vs(0.42±0.24)μIU/L](P0.05)。结论条件性失活胰岛β细胞PP2Acα小鼠糖耐量受损可能与胰岛素一相分泌受损相关。     

Pax6突变杂合子小鼠糖代谢异常的分子机制

目的探讨Pax6突变杂合子小鼠是否存在糖代谢异常,并对其分子机制进行研究。方法采用腹腔注射葡萄糖耐量试验（IPGTT）,观察Pax6突变杂合子小鼠血糖和胰岛素原／总胰岛素比值的变化,胰岛素耐量试验（ITT）分析胰岛素敏感性的变化;小鼠离体胰岛采用定量PCR和Western印迹分析检测激素原转化酶1（PCI）表达;小鼠胰岛8细胞系用于染色质免疫共沉淀Ch1P分析以确定PAX6蛋白能否与Pc1基因启动子区域相结合,进而采用荧光素酶报告分析观察Pax6突变对Pc1基因表达的影响。结果与野生型小鼠相比,Pax6突变杂合子小鼠在6月龄时存在明显的负荷后高血糖,胰岛素敏感性未见显著变化,胰岛素原／总胰岛素比值不适当升高早于负荷后高血糖,类似人类Pax6基因突变的无虹膜症患者中糖代谢异常的表型特征。Pax6突变杂合子小鼠胰岛中PCI表达水平显著降低。PAX6蛋白可直接结合到Pc1基因启动子区域,野生型PAX6可上调Pc1表达,而突变型PAX6则无此作用。结论PAX6通过PCI介导的胰岛素原剪切加工调控葡萄糖代谢,这是PAX6的一种新功能。PCI缺乏引起的胰岛素原剪切加工缺陷是Pax6突变导致葡萄糖代谢异常的最重要分子机制之一。     

外源性硫化氢对巨噬细胞泡沫化过程中钙化的抑制作用

目的研究脂蛋白脂酶(LPL)基因缺陷对载脂蛋白E单基因敲除(apoE-/-)糖尿病小鼠的动脉粥样硬化及糖尿病肾病进展的影响。方法实验选取3个月雄性apoE-/-以及apoE和LPL双基因敲除(apoE-/-LPL+/-,即ELK+/-)小鼠,腹腔注射链脲霉素(STZ)60mg/(kg·d),连续注射7天以诱导1型糖尿病,非糖尿病组给予等量缓冲液注射。造模前及两周后取眶静脉血,监测血糖、血浆甘油三酯和总胆固醇,以后每四周取血一次,监测血生化指标。分别于实验开始和结束前....     

中药栀子对大鼠血糖水平、胰岛功能及结构的影响

目的 探讨长时间摄入中药栀子对正常大鼠血糖水平、胰岛功能及结构的影响.方法 将30只大鼠随机分为对照组、栀子组、模型组,每组10只.模型组禁食12 h后,按照65 mg/kg体质量一次腹腔注射1％脲佐菌素溶液制作糖尿病模型.栀子组按10 mL/kg体质量给予栀子水煎剂灌胃,对照组与模型组予等量生理盐水灌胃,连续给药40d.41 d后处死大鼠,腹主静脉取血,分离血清,测定血糖、糖化血红蛋白（HbA1C）、胰岛素（INS）、α-淀粉酶（AMY）及C肽（C-P）水平;取胰腺组织制作切片HE染色,光镜下观察胰腺组织病理变化.结果 栀子组血糖、HbA1c、INS、C-P均低于对照组,血糖、HbA1c、C-P低于模型组（P均＜0.05）.与模型组相比,INS及C-P水平无统计学差异.栀子组胰岛组织增生肥大,炎性细胞浸润.结论 中药栀子可降低大鼠血糖水平,但长时间用药对胰岛结构有损伤作用.     

替米沙坦对db／db小鼠胰岛分泌功能影响的研究

目的探讨替米沙坦阻断肾素一血管紧张素系统（RAS）对db／db小鼠胰岛分泌功能的影响。方法将8周龄db／db小鼠随机分为两组,分别给予6周替米沙坦或安慰剂灌胃治疗,同周龄的db／m小鼠作为非糖尿病对照。喂药6周后行糖耐量实验,然后取胰腺,进行胰岛素免疫组化检测,另用离体胰岛灌流系统测定胰岛素第一时相的分泌。结果替米沙坦组治疗6周后空腹血糖显著下降（P〈0．05）。糖负荷120min后葡萄糖曲线下面积（AUC）低于安慰剂对照组（P〈0．05）,AUCIns0-30高于安慰剂对照组（P〈0．05）。离体胰岛灌流结果显示,替米沙坦组胰岛素第一时相分泌得到改善。胰岛内胰岛素表达强度替米沙坦组明显高于安慰剂对照组。结论替米沙坦能改善糖耐量,恢复胰岛素第一时相分泌,保护β细胞功能。     

醋酸敏感的G蛋白耦联受体FFAR2调控胰岛素分泌机制的研究

目的探讨对醋酸敏感的G蛋白耦联受体-短链脂肪酸受体2(FFAR2)及其配体对胰岛素分泌的影响和相关机制。方法使用以C57BL/6J为背景的野生型(WT)小鼠(n=17)和敲除编码受体基因Ffar2的转基因(KO)小鼠(n=15),分别于第6周和第26周测定体重、空腹血糖及胰岛素水平。提取小鼠胰岛细胞,随机分组分别给予不同浓度葡萄糖和FFAR2配体物质(SCA14、SCA15、CPTB和CMTB)刺激,并使用ELISA方法测定胰岛素分泌量。结果不同基因型小鼠的体重、空腹血糖及胰岛素水平差异无统计学意义(P均0.05)。体外胰岛β细胞胰岛素分泌实验中,KO型胰岛细胞在低浓度葡萄糖刺激下胰岛素分泌量与WT型无差别,高浓度葡萄糖刺激下KO型胰岛细胞胰岛素分泌量少于WT型,差异有统计学意义(P0.05)。类似生理浓度的醋酸盐(1mM)刺激胰岛素分泌,在WT型胰岛细胞中,胰岛素分泌量是无醋酸盐时的2倍以上,在KO型胰岛细胞中,促进作用减弱。FFAR2配体物质SCA14、SCA15在WT型同样促进胰岛素分泌,而在KO型胰岛细胞中则无类似作用。另一类FFAR2配体物质CMTB、CPTB在WT型和KO型胰岛细胞中均抑制胰岛素分泌。结论敲除Ffar2不影响小鼠的生长发育。FFAR2可调控胰岛素分泌,并具有血糖依赖性。作为FFAR2的主要配体,醋酸可刺激胰岛素分泌且具有受体依赖性。其他FFAR2配体中,SCA14、SCA15与醋酸作用类似,但CPTB和CMTB抑制胰岛素分泌且不依赖受体产生作用。     

链脲菌素剂量对C57BL/6J小鼠糖尿病诱导效应的影响

目的 观察不同剂量链脲菌素(STZ)对C57BL/6J小鼠糖尿病诱导效应的影响,探讨其量效关系及最佳剂量范围.方法 将C57BL/6J小鼠按数字随机法分为9个STZ剂量组(A～I组,STZ分别为30、60、80、100、120、150、180、210、240 ms/kg体重),每组15只,腹腔注射;1个对照组,10只,腹腔注射等体积缓冲液.观察各组血糖、体重、血胰岛素和45 d生存率的变化,分析其与STZ剂量的关系.同时取A、C、G及对照组小鼠胰腺、肾脏组织做病理学检杏,并行免疫组化观察胰腺胰岛素及肾脏CD<,68>的表达.结果 C～G组较对照组血糖增高、体重及血胰岛素含量较对照组下降非常显著(P<0.05),且STZ剂量与血糖呈正相关(r=0.984,P<0.05),与血胰岛素含量呈负相关(r=-0.994,P<0.05).C～G组成模率达86.7%～100%,显著高于A、B组的0和40%(P<0.05);45 d生存率为46.7%～73.3%,显著高于H、I组的13.3%和0(P<0.05).A组胰腺、肾脏组织未见明显破坏;C组及G组出现典型的胰岛萎缩变形,胰岛素分泌颗粒减少,肾小球系膜外基质沉着及球周臣噬细胞浸润.结论 C57BL/6J小鼠腹腔注射STZ以80～180 mg/kg体重的剂量制模率高、生存率高,且靶器官损伤典型;该剂量与血糖呈正相关,与血胰岛素含量呈负相关.     

依折麦布对db/db糖尿病小鼠胰岛分泌功能的影响

目的 探讨依折麦布对db/db小鼠胰岛分泌功能的作用.方法 将8周龄的db/db小鼠随机分为2组,分别给予6周依折麦布或安慰剂灌胃治疗,同周龄的db/m小鼠作为非糖尿病对照.投药6周后行糖耐量试验后取胰腺,进行胰岛素免疫组织化学检测,另采用离体胰岛灌流系统测定胰岛素第一时相的分泌.结果 依折麦布组治疗6周后空腹血糖显著下降,同时总胆固醇及低密度脂蛋白胆固醇低于对照组(P＜0.05).糖负荷120 min后葡萄糖曲线下面积低于db/db对照组(P＜0.05),AUCINS0-30高于对照组(P＜0.05).离体胰岛灌流结果显示依折麦布组胰岛第一时相分泌得到改善.胰岛内胰岛素表达强度依折麦布组明显高于对照组.结论 依折麦布能改善糖耐量,恢复胰岛第一时相分泌,保护β细胞功能.     

吡格列酮对糖尿病大鼠胰岛β细胞的保护作用及机制探讨

目的观察吡格列酮对糖尿病大鼠胰岛β细胞的保护作用,并探讨其机制。方法将雄性Wistar大鼠30只随机分为三组各10只。模型组、吡格列酮组采用腹腔注射链脲佐菌素建立糖尿病大鼠模型,对照组腹腔注射等量枸橼酸缓冲液;造模成功后吡格列酮组予吡格列酮10 mg/（kg·d）灌胃,另两组予等量生理盐水灌胃。16周后断尾取血测空腹血糖（FPG）,心包取血测糖化血红蛋白（HbA1c）和空腹胰岛素水平（FINS）,并计算胰岛素抵抗指数（HOMA-IR）,另取胰腺组织行HE染色,电镜下观察病理变化。结果吡格列酮组FPG、HbA1c、FINS、HOMA-IR水平明显低于模型组,病理改变轻于模型组。结论吡格列酮对糖尿病大鼠胰岛β细胞有保护作用,其机制可能为降低血糖、HbA1c和FINS,改善糖毒性和胰岛素抵抗。     

雌激素对胰腺大部分切除模型小鼠胰岛β细胞功能影响的研究

目的观察雌激素干预C57BL/6小鼠大部分胰腺切除后胰岛功能的变化,探讨雌激素对胰岛β细胞的影响。方法 60只小鼠随机分成4组:对照假手术组(Sham)、胰腺切除模型组(Px)、雌激素干预组(E2)和雌激素阻断剂组(E2+ICI),每组15只。ELISA检测血浆胰岛素水平;小鼠处死前进行葡萄糖耐量实验(GTT);处死后荧光染色胰岛,计算胰岛数量和体积,并进行葡萄糖刺激胰岛素分泌实验(GSIS);RT-PCR检测Ins-1、Ins-2和PDX-1基因的表达水平。结果胰腺切除手术后7 d,E2组血糖较Px组下降[(162±18)vs(225±11)mg/dl),P0.05]。GTT结果显示,服糖120 min后,E2组与Px组比较,血糖回落到基线水平[(145.5±24.5)vs(235.0±21.3)mg/dl,P0.05]。胰岛荧光染色结果表明,各手术组的胰岛体积明显增大(P0.05),尤其是E2组胰岛体积增大最为明显。GSIS结果发现,雌激素能显著增加胰岛素释放及胰岛素含量。RT-PCR结果提示,雌激素能增加胰岛Ins-2基因的表达。结论雌激素干预可降低糖尿病小鼠血糖水平,增加胰岛体积和胰岛素分泌,并对胰岛素基因的表达产生影响。     

Three layer functional model and energy exchange concept of aging process

Relying on a certain degree of abstraction, we can propose that no particular distinction exists between animate or living matter and inanimate matter. While focusing attention on some specifics, the dividing line between the two can be drawn. The most apparent distinction is in the level of structural and functional organization with the dissimilar streams of ‘energy flow’ between the observed entity and the surrounding environment. In essence, living matter is created from inanimate matter which is organized to contain internal intense energy processes and maintain lower intensity energy exchange processes with the environment. Taking internal and external energy processes into account, we contend in this paper that living matter can be referred to as matter of dissipative structure, with this structure assumed to be a common quality of all living creatures and living matter in general. Interruption of internal energy conversion processes and terminating the controlled energy exchange with the environment leads to degeneration of dissipative structure and reduction of the same to inanimate matter, (gas, liquid and/or solid inanimate substances), and ultimately what can be called ‘death.’ This concept of what we call dissipative nature can be extended from living organisms to social groups of animals, to mankind. An analogy based on the organization of matter provides a basis for a functional model of living entities. The models relies on the parallels among the three central structures of any cell (nucleus, cytoplasm and outer membrane) and the human body (central organs, body fluids along with the connective tissues, and external skin integument). This three-part structural organization may be observed almost universally in nature. It can be observed from the atomic structure to the planetary and intergalactic organizations. This similarity is corroborated by the membrane theory applied to living organisms. According to the energy nature of living matter and the proposed functional model, the decreased integrity of a human body's external envelope membrane is a first cause of the structural degradation and aging of the entire organism. The aging process than progresses externally to internally, as in single cell organisms, suggesting that much of the efforts towards the restoration and maintenance of the mechanisms responsible for structural development should be focused accordingly, on the membrane, i.e., the skin. Numerous reports indicate that all parts of the human body, like: bones, blood with blood vessels, muscles, skin, and so on, have some ability for restoration. Therefore, actual revival of not only aging tissue of the human body's membrane, but the entire human body enclosed within, with all internal organs, might be expected. We assess several aging theories within the context of our model and provide suggestions on how to activate the body's own anti-aging mechanisms and increase longevity. This paper presents some analogies and some distinctions that exist between the living dissipative structure matter and inanimate matter, discusses the aging process and proposes certain aging reversal solutions.     

Unusual responses of nocturnal pineal melatonin synthesis and secretion to swimming: Attempts to define mechanisms

Abstract: The effect of swimming at night on rat pineal melatonin synthesis was compared with that of light exposure at night. Rats were forced to swim at 0030 hr (lights out at 2000 hr) and sacrificed by decapitation 15 and 30 min later, immediately after swimming. Other groups of animals were exposed to white light (650μW/cm²) for 15 and 30 min at same time. Swimming caused a rapid and highly significant drop in the melatonin content in the pineal gland; however, the activity of N-acetyltransferase (NAT), the supposed rate limiting enzyme in the melatonin production, was not changed. Despite the drop in pineal melatonin levels, serum concentrations of the indole remained elevated in the rats that swam. In contrast, melatonin levels in the pineal and serum of light exposed rats fell precipitously, accompanied by a significant suppression of NAT activity. Since we anticipated that the strenuous exercise associated with swimming may induce release of artrial natriuretic peptide (ANP) from the heart, which in turn could cause the release of pineal melatonin, in a second study we injected physiological saline intravenously to stretch the cardiac muscle and release ANP. Three milliliters of normal saline was injected during the day into the jugular vein of anesthetized rats that were pretreated with isoproterenol to stimulate pineal melatonin production. Animals were killed 15 min after the saline injection, and pineal NAT activity and pineal melatonin levels were measured. The saline injections caused no alteration in the elevated levels of either NAT or melatonin. These data suggest that the disparity in pineal NAT activity (which was high) and pineal melatonin (which was low), in animals swum at night, may not be caused by ANP which is released during strenuous exercise such as swimming.     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Melatonin and photoperiodic time measurement: Seasonal breeding in the sheep

Abstract: Well-established circadian physiology supports the view that photoperiodic time measurement utilizes the coincidence between the presence of light and a photosensitive phase of a 'biological clock' to alter reproductive status—the so-called external coincidence model of seasonal breeding. In this review, we examine the mechanism whereby photoperiod interacts with presumed suprachiasmatic nuclei activity to allow endogenous melatonin to normally synchronize reproductive activity to the optimal time of year. The Romney Marsh sheep is particularly explored as an experimental model. It is suggested that the on/off activity of seasonal reproduction may be a robust mechanism able to be predictably manipulated by the judicious use of the light/dark cycle and exogenous melatonin, but firmly based on circadian principles.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Conservative management of perforated duodenal diverticulum： A case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.     

Language of CTO interventions – Focus on hardware

The knowledge of variety of chronic total occlusion (CTO) hardware and the ability to use them represents the key to success of any CTO interventions. However, the multiplicity of CTO hardware and their physical character and the terminology used by experts create confusion in the mind of an average interventional cardiologist, particularly a beginner in this field. This knowledge is available but is scattered. We aim to classify and compare the currently used devices based on their properties focusing on how physical character of each device can be utilized in a specific situation, thus clarifying and simplifying the technical discourse.