空腹C肽质量浓度与胰岛素抵抗相关性研究

目的比较C肽和胰岛素在评估胰岛素抵抗性(IR)的差异。方法依口服糖耐量试验将2003年3月至2004年3月中国医科大学附属第二医院门诊及周围社区的44例汉族人分为正常糖耐量(NGT)组、孤立空腹血糖受损(I-IFG)组、孤立糖耐量受损(I-IGT)组,联合糖耐量受损(C-IGT)组。观察葡萄糖钳夹试验测定的IR指标(葡萄糖输注速率,GIR)和其空腹胰岛素、C肽的关系。结果I-IFG、I-IGT、C-IGT组的GIR明显低于NGT(P<0.01),但各组的空腹C肽浓度差异无显著性。各组的胰岛素作用指数(IAI)、稳态模式评估法指数(HOMA-IR)、空腹胰岛素衍生的IR指标定量胰岛素敏感性检测指数(QUICKI)与GIR均呈良好相关(P<0.05),相关系数在0.766~0.498之间,但空腹C肽替代胰岛素后的IR指标与GIR无明显相关,相关系数在0.394~0.042之间(P>0.05)。结论空腹C肽质量浓度和胰岛素抵抗程度没有相关性。     

不同状态的糖调节受损患者胰岛素分泌和胰岛素敏感性的差异

目的评估初发的单纯空腹血糖受损（IFG）和单纯糖耐量受损（IGT）患者的胰岛素分泌以及胰岛素敏感性（IS）特征。方法北京市东城区既往无糖尿病史的2388名受试者行葡萄糖耐量试验,同时行胰岛素释放试验,本文纳入2244例,其中糖耐量正常（NGT）1608例,IFG240例,IGT243例,IFG＋IGT 153例。比较各组胰岛素抵抗指数（HOMA-IR）、IS指数（Matsudaindex）、B细胞功能指数（1相Stumvoll index、△I30／△G30）。结果与NGT组比较,其余三组HOMA-IR显著升高,Matsuda指数及B细胞功能指数均显著降低（P均〈0．01）;IFG组HOMA-IR及Matsuda指数均高于IGT组;IFG组△I30／△G30高于IGT组,而Stumvoll指数低于IGT组（P〈0．01）;与IFG组、IGT组比较,IFG＋IGT组HOMA-IR显著升高,Matsuda指数、1相Stumvoll指数显著降低（P均〈0．01）。结论糖尿病前期人群存在不同程度的胰岛素分泌缺陷和IR,IFG组肝IR较重,而IGT组肌肉IR较重。     

糖尿病前期人群的胰岛β细胞功能和胰岛素抵抗的探讨

目的评价糖调节受损（IGR）不同组分的胰岛素抵抗（IR）和胰岛β细胞功能状况。方法OGTT筛查北京地区无DM史中老年人群，据2003年ADA标准，分为正常糖耐量（NGT）组、空腹血糖受损（IFG）组、糖耐量减低（IGT）组、及IFG合并IGT（IFG＋IGT）组，检测各组胰岛素抵抗指数（HO-MA-IR）、胰岛素敏感指数（ISI-Stumvoll）、β细胞功能指数（HBCI/IR）及第一、二时相胰岛素分泌指数。结果（1）IFG组：HOMA-IR显著高于NGT组和IGT组，ISI-Stumvoll高于IGT组（P均〈0.05），HBCI/IR显著低于NGT组和IGT组（P〈0.05）；（2）IGT组：HOMA-IR和HBCI/IR均位于NGT组和IFG组之间，ISI-Stumvoll、第一时相和第二时相胰岛素分泌指数显著低于NGT组和IFG组（P均〈0.05）；（3）IFG＋IGT组：HOMA-IR高于NGT组、IFG组和IGT组，ISI-Stumvoll显著低于NGT组和IFG组（P均〈0.05），HBCI/IR显著低于NGT组和IGT组（P均〈0.05）；（4）在非糖尿病人群中，随着FPG及2hPG的升高，HOMA-IR有递增趋势，ISI-Stumvoll、第一时相和第二时相胰岛素分泌指数有递减趋势（P均〈0.05）。结论IFG主要是肝脏IR和基础状态时的胰岛β细胞分泌功能受损。IGT的肌肉IR较重，其糖负荷后的胰岛β细胞分泌功能受损较重。在非糖尿病人群，FPG和2hPG的升高与IR呈正相关，与胰岛β细胞功能呈负相关。     

单纯IGT和单纯IFG个体高敏C反应蛋白水平的差异及相关因素分析

目的比较正常空腹血糖／正常糖耐量（NFG／NGT）、空腹血糖受损（IFG）、糖耐量减低（IGT）及IFG／IGT个体的血清高敏C反应蛋白（hsC-RP）水平的差异，并对其相关因素进行分析。方法将443名39～65岁非糖尿病（DM）个体根据OGTT分为以下4组：NFG／NGT、单纯IFG、单纯IGT和IFG／IGT组。比较各组间血清hsC-RP的差异，并对与之相关的变量进行统计学分析。结果IGT组比IFG组hsC-RP水平明显升高（P〈0．05），IFG组与NFG／NGT组以及IGT组与IFG／IGT组间的hsC-RP水平没有明显统计学差异（P〉0．05）。多元逐步回归分析显示，BMI和胰岛素抵抗指数是hsC-RP的独立预告因子。结论IGT比IFG个体的血清hsC-RP水平明显升高，hsC-RP与胰岛素抵抗和代谢综合征的多种组分相关。     

不同糖耐量人群胰岛素抵抗和胰岛β细胞功能减退的差异

目的探讨不同糖耐量人群胰岛素抵抗（IR）和胰岛B细胞功能状态。方法分析5523例患者行OGTT和胰岛素释放试验的结果，根据WHO标准将研究对象分为糖代谢正常（NGT）组、单纯空腹血糖升高（IFG）组、单纯糖耐量减低（IGT）组、空腹血糖升高合并糖耐量受损（IFG＋IGT）组和2型糖尿病（T2DM）组。结果（1）HOMA-IR：IFG、IGT、IFG＋IGT和T2DM组比NGT组分别增加41％、19％、47％和69％（P〈0．01）。（2）校正IR影响后，IFG、IGT、IFG＋IGT和T2DM组比NGT组HOMA-β分别下降54％、19％、55％和68％，△I30/△G30分别下降47％、40％、63％和82％（P〈0．001）；IFG、IFG＋IGT和T2DM组AUCI比NGT组分别下降27％、26％和30％（P〈0．01）。结论（1）从IGT、IFG、IFG＋IGT到T2DM发展过程中IR程度逐渐加重，胰岛β细胞早时相分泌和基础分泌功能逐渐衰竭，晚时相分泌代偿能力功能减弱，总体分泌功能逐渐减退。（2）从NGT、IGT、IFG、IFG＋IGT到T2DM的糖代谢异常发生发展过程反映了胰岛β细胞早时相、基础和整体分泌功能逐渐衰退变化规律。     

空腹血糖受损人群胰岛素抵抗和胰岛β细胞功能特点分析

目的　探讨我国空腹血糖受损 (IFG)人群胰岛素抵抗 (IR)和胰岛 β细胞功能的特点。 方法　根据口服 75g葡萄糖耐量试验将 13 0 45例≥ 2 5岁的中国人群分为糖耐量正常 (NGT)组 ,IFG组 ,糖耐量低减 (IGT)组和IFG/IGT组 ,利用HOMA胰岛素抵抗指数 (HOMA IR)、HOMAβ细胞功能指数 (HBCI)、第 1和第 2时相胰岛素释放指数等进行组间比较和多因素分析。结果　 (1)与NGT组相比 ,IFG组体重指数、腰臀围比值、空腹胰岛素、血清甘油三酯、血压、HOMA IR明显升高 ,而HBCI、第 1和第 2时相胰岛素释放指数明显降低 (P <0 .0 1～P <0 .0 0 1)。Logistic回归分析显示 :HOMA IR与IFG发生的一致性高达 0 .66～ 0 .79(均P <0 .0 0 1)。 (2 )与IGT组相比 ,IFG组OGTT 2h胰岛素水平显著低于IGT(P <0 .0 0 1)。Logistic回归分析显示 :HOMA IR、第 1和第 2时相胰岛素分泌指数与IFG发病显著正相关 ,HBCI与IFG发病显著负相关 ,各方程预测IFG发生的一致性高达 0 .5 6～ 0 .74(均P <0 .0 0 1)。结论　IFG者空腹状态下的胰岛素敏感性和 β细胞功能均较NGT和IGT者差 ,而糖负荷后的胰岛素分泌状态比NGT者差 ,但明显好于IGT者 ,因此 ,IFG者可能存在空腹及餐后IR和 β细胞功能的分离状态 ,是一组有别于IGT的糖稳态受损人群。     

NGT进展为IGT过程中IR与β细胞功能演变

对148例正常个体进行2年随访，其中14例进展为IGT，110例仍NGT，12例为IFG，8例进展为DM,4例进展为IGT＋IFG，总共124例作为研究对象。结果：（1）与NGT组比，IGT组OGTT30min血糖、EINS及HOMA—IR明显升高（P〈0．05），而半小时胰岛素、早期胰岛素分泌指数（P〈0．05）、胰岛素敏感指数降低（P〈0．05）。（2）与IGT基线资料相比，BMI、OGTT2小时血糖、半小时血糖、空腹胰岛素（FINS）及HOMA—IR升高（P〈0．05），而半小时胰岛素、早期胰岛素分泌指数（P〈0．05）、胰岛素敏感性指数降低（P〈0．05）。结论：从NGT向IGT进展过程中，存在胰岛素抵抗程度增加和早期胰岛素分泌功能减退。     

空腹血糖受损与糖耐量受损者胰岛β细胞功能及胰岛素抵抗的比较

对231例糖耐量正常（NGT），40例空腹血糖受损（IFG），196例糖耐量受损（IGT）和45例IGT兼有IFG的病例研究显示，IFG（FPG≥6．1mmol／L）组的胰岛素分泌缺欠和胰岛素抵抗比IGT组更严重；IGT组中仅19％例出现IFG。     

空腹血糖异常、糖耐量减低患者血清胰岛素水平的变化及其意义

目的 观察空腹血糖异常(IFG)、糖耐量减低(IGT)患者血清胰岛素水平的变化。方法 对50例空腹血糖和糖耐量正常者(NGT)、40例IFC和80例IGT患者行口服葡萄糖耐量试验(0GTT)，用氧化酶法检测血糖，用放免法测定血清空腹及餐后2小时胰岛素。结果 IFG、IGT组空腹血糖、空腹胰岛素水平及胰岛素敏感指数较NGT组明显升高(P＜0.05或P＜0．01)，IFG组胰岛素敏感指数与IGT组比较无显著性差异(P＞0．05)。结论 在IFG、IGT状态下已经存在胰岛素抵抗，而且在程度上两者间并没有显著性差异，应早期干预治疗。     

空腹血糖切点下调对发现糖尿病高危人群的影响

根据口服糖耐量试验将34例沈阳地区研究对象分为正常糖耐量(NGT)组、新生腹血糖受损(新IFG)组、新糖耐量减低(新IGT)组和旧糖耐量减低(旧IGT)组.运用高胰岛素正葡萄糖钳夹技术测定胰岛素抵抗程度,用静脉葡萄糖刺激胰岛素释放试验测定胰岛素一相分泌量和二相分泌量.结果胰岛素钳夹试验NGT、新IFG、新IGT、旧IGT组的葡萄糖输注速率(GIR,mg/kg/min)分别为10.2±0.9;6.0±0.9;58±0.7;44±0.3.新IFG、新IGT、旧IGT组均比NGT组显著减低(P＜0.001;P＜0.001;P＜0.001).胰岛β细胞功能①胰岛素-相分泌量(mU/l)新IFG、新IGT、旧IGT组分别为220±61;331±89;115±18;与NGT组(221±27)相比,新IFG和NGT组处于同一水平,但新IGT有高于NGT组的趋势,而旧IGT组有降低趋势但无统计学差异(P＞0.05).②胰岛素二相分泌量(mU/l)NGT、新IFG、新IGT、旧IGT组分别为88±7;110±19;220±80;122±7,新IGT组明显高于其它三组(P＜0.01;P＜0.05;P＜0.05).结论新旧空腹血糖切点划分出的IGR均出现了胰岛素抵抗,胰岛素的分泌模式也和NGT有了差异.     

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.     

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.     

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.     

Serological survey of HIV and syphilis in pregnant women in Madagascar

Objectives Peripartal transmission of human immunodeficiency virus (HIV) and Treponema pallidum, the causative agent of syphilis, leads to severe consequences for newborns. Preventive measures require awareness of the maternal infection. Although HIV and syphilis testing in Madagascar could be theoretically carried out within the framework of the national pregnancy follow‐up scheme, the required test kits are rarely available at peripheral health centres. In this study, we screened blood samples of pregnant Madagascan women for HIV and syphilis seroprevalence to estimate the demand for systemic screening in pregnancy. Methods Retrospective anonymous serological analysis for HIV and syphilis was performed in plasma samples from 1232 pregnant women that were taken between May and July 2010 in Ambositra, Ifanadiana, Manakara, Mananjary, Moramanga and Tsiroanomandidy (Madagascar) during pregnancy follow‐up. Screening was based on Treponema pallidum haemagglutination tests for syphilis and rapid tests for HIV, with confirmation of positive screening results on line assays. Results Out of 1232 pregnant women, none were seropositive for HIV and 37 (3%) were seropositive for Treponema pallidum. Conclusions Our findings are in line with previous studies that describe considerable syphilis prevalence in the rural Madagascan population. The results suggest a need for screening to prevent peripartal Treponema pallidum transmission, while HIV is still rare. If they are known, Treponema pallidum infections can be easily, safely and inexpensively treated even in pregnancy to reduce the risk of transmission.     

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.