Evaluation of the osmoregulatory function of taurine in brain cells

Summary Homogenous primary cultures of mouse astrocytes and cortical neurons were used to clarify the role of taurine in ion and osmoregulation in the CNS. This study indicates that both neurons and glial cells have uptake systems for taurine. The cell water content does not change during loading of cells with taurine. Chemical analysis indicates that part of the accumulated taurine is metabolized and that the product(s) are stored in the cells. Extracellular taurine (1 mM) has no effect on K⁺, Na⁺, Cl^-, or Ca²⁺ movements in astrocytes. However, astrocytes loaded to a taurine content which corresponds a concentration of 60 mM (corresponds to normal mouse cortex levels) show a 50% reduction in their K⁺ accumulation by carriers and a 100% increase in Ca²⁺ turnover rates. Movements of Ca²⁺ and K⁺ are involved in neurotransmission. It appears that taurine stored in glial cells, has an important effect on ion homeostasis in the CNS and may act indirectly on neuronal excitability.     

Body fluid changes, thirst and drinking in man during free access to water

To investigate whether human thirst and drinking during ad lib access to water occur in response to body fluid deficits, we obtained blood samples and visual analog scale thirst ratings from five healthy, volunteer, young men at hourly intervals and when they were thirsty during a normal working day. Although there were significant increases in ratings of thirst, pleasantness of drinking water, mouth dryness and unpleasantness of the taste in the mouth when subjects were thirsty enough to drink compared with intervening intervals, there were no concomitant changes in body fluid variables (microhematocrit, plasma osmolality and plasma sodium, potassium, protein and angiotensin II concentrations). Subjects drank mainly in association with eating and were not overhydrated as indicated by constantly hypertonic urine and significant tubular reabsorption of free water over the experimental period. The results indicate that during free access to water humans become thirsty and drink before body fluid deficits develop, perhaps in response to subtle oropharyngeal cues, and so provide evidence for anticipatory thirst and drinking in man.     

Long-lasting increase in the set point for cocaine self-administration after escalation in rats

Rationale: When access time to a continuous schedule of drug self-administration is restricted, animals tend to limit intake to a certain level over time and across doses. This observation suggests an endogenous constraint or set point that determines the individual’s preferred level of pharmacological effects. Objectives: To assess whether the transition to increased levels of drug intake is associated with a change in set point. Methods: Two groups of rats were trained on a 1-h continuous schedule of cocaine self-administration (250 μg/injection), after which access to cocaine was increased to 6 h in one group (Long Access or LgA rats) or kept to 1 h in the other group (Short Access or ShA rats). After 22 sessions on this regimen, different doses of cocaine were tested (31.25, 62.5, 125, and 250 μg/injection). For each dose, the post-response time-out period was reduced to 4 s to reduce any temporal limitations on self-injections and subjects were tested several times. Results: In LgA rats, the first hour intake escalated over time and eventually reached a level 200% greater than that of ShA rats. Though all rats maintained relatively constant intake across doses, LgA rats took nearly two times as much cocaine than ShA rats. When access to cocaine for LgA rats was reduced to 1 h, intake returned very slowly toward pre-escalation levels but was still elevated even after 2 months of reduced availability. Conclusions: These data suggest that the transition to escalated levels of intake is associated with a long-lasting change in cocaine set point. Received: 12 February 1999 / Final version: 21 May 1999     

不同浓度含钠电解质溶液复苏对烧伤小儿机体内环境的影响

目的观察两种不同含钠浓度的电解质溶液对小儿烧伤液体复苏后机体内环境的影响。方法选择40例年龄6个月至两岁的小儿烧伤病例,烧伤面积从25%～54%,随机分成俩组,每组20例,A组采用平衡盐溶液(A组含钠量130mmol/L),B组采用高钠复方乳酸钠溶液(含钠量174mmol/L),两种不同的电解质溶液行液体复苏。并分别于伤后1～4天抽取血标本检测K 、Na 、Cl-和HCO3-四种电解质,记录各时段液体输入量和尿量以及血浆晶体渗透压等。结果A组伤后第一天的补液量明显高于B组,且A组血清Na 、HCO3-浓度明显下降,伤后第二天逐步回升。A、B两组K 浓度于伤后第三、第四天明显下降。结论电解质溶液中钠离子浓度的不同对小儿烧伤机体内环境的影响较大,含钠量高的溶液可能更有利于烧伤小儿机体内环境保持稳定。     

羟乙基淀粉130/0.4急性高容量血液稀释对骨科手术患者内环境的影响

目的探讨硬膜外复合全身麻醉下6%羟乙基淀粉130/0.4急性高容量血液稀释对骨科手术患者内环境的影响。方法选择ASAⅠ或Ⅱ级择期骨科手术患者28例,随机均分为急性高容量血液稀释组(AHH组)和对照组(C组)。均采用硬膜外阻滞复合全身麻醉。AHH组硬膜外阻滞起效后开始血液稀释,快速输入6%羟乙基淀粉130/0.420ml/kg,速率50ml/min;C组常规输液。术中连续监测MAP、HR、SpO2、CVP、ECG和PETCO2。分别于稀释前即刻(T0)、稀释后5min(T1)、120min(T2)采取桡动脉血进行电解质、乳酸(Lac)、血糖(BG)、尿素氮(BUN)、Hct及Hb测定,计算血浆渗透浓度(Posm)。结果AHH组Hct及Hb血液稀释后下降约20%。与C组相比,AHH组患者的MAP、HR较平稳,术中输液量、尿量增多。与T0相比,AHH组T1时CVP升高,T2时pH值降低(P<0.05)。两组患者的BG在T2时增高,且C组高于AHH组(P<0.05)。两组各时点血电解质、Lac、BUN、HCO3-、BE、Posm等各指标差异均无统计学意义。结论硬膜外复合全身麻醉下6%羟乙基淀粉130/0.4急性高容量血液稀释能维持内环境的相对稳定。     

Expression and characterization of αvβ5 integrin on intestinal macrophages

Macrophages play a crucial role in maintaining homeostasis in the intestine, but the underlying mechanisms have not yet been elucidated fully. Here, we show for the first time that mature intestinal macrophages in mouse intestine express high levels of αvβ5 integrin, which acts as a receptor for the uptake of apoptotic cells and can activate molecules involved in several aspects of tissue homeostasis such as angiogenesis and remodeling of the ECM. αvβ5 is not expressed by other immune cells in the intestine, is already present on intestinal macrophages soon after birth, and its expression is not dependent on the microbiota. In adults, αvβ5 is induced during the differentiation of monocytes in response to the local environment and it confers intestinal macrophages with the ability to promote engulfment of apoptotic cells via engagement of the bridging molecule milk fat globule EGF‐like molecule 8. In the absence of αvβ5, there are fewer monocytes in the mucosa and mature intestinal macrophages have decreased expression of metalloproteases and IL 10. Mice lacking αvβ5 on haematopoietic cells show increased susceptibility to chemical colitis and we conclude that αvβ5 contributes to the tissue repair by regulating the homeostatic properties of intestinal macrophages.     

Associations between serum amino acids and incident type 2 diabetes in Chinese rural adults

Background and aimsSome amino acids (AAs) may be associated with type 2 diabetes (T2DM). This study aimed to determine the associations of individual AAs with the development of T2DM in rural Chinese adults.Methods and resultsA cohort study of 1199 individuals aged 18 years or older was conducted from 2006 to 2008 in a rural community of Deqing, China, a repeated survey was done in 2015 and data linkage with the electronic health records system was performed each year for identifying new T2DM cases. A high-performance liquid chromatography approach was used to measure the baseline serum concentrations of 15 AAs. Cox proportional hazards models were used to examine the associations between AAs and the risk of incident T2DM. A total of 98 new T2DM cases were identified during the follow-up of 12 years on average. Among 15 AAs, proline was associated with an increased risk of incident T2DM after adjusted for age, sex, body mass index, fasting plasma glucose, family history of T2DM, smoking status, alcohol use, and history of hypertension, the adjusted hazard ratio for 1-standard deviation increment was 1.20 (95% confidence interval: 1.00, 1.43). The association tended to be more marked in subjects younger than 60 years and overweight/obese subjects. Among participants without hypertension, proline and phenylalanine were associated with an increased risk of incident T2DM, while aspartic acid was associated with a decreased risk.ConclusionSerum proline was associated with the risk of incident T2DM in rural Chinese adults and might be a potential predictor.     

Clinical evaluation of insulin resistance and β-cell function by the homeostasis model assessment in patients with systemic lupus erythematosus

The aim of this preliminary study was to evaluate insulin resistance and secretion using homeostasis model assessment (HOMA) in patients with systemic lupus erythematosus (SLE). The fasting glucose and insulin concentrations, HOMA insulin resistance (IR), HOMA -cell, antidouble-stranded DNA antibodies (anti-dsDNA), C3, C4, and SLE disease activity index (SLEDAI) were determined in a total of 58 female SLE patients. All patients were classified into subgroups according to the presence of anticardiolipin antibodies (aCL+ vs. aCL-) and SLEDAI scores (SLEDAI <3 vs. SLEDAI >3). Results showed that SLE patients with and without aCL had significantly higher fasting insulin levels, HOMA IR, and HOMA -cells than controls. Similar results were also found in SLE patients with different disease activities. Pearsons correlation analysis showed that there was a highly significant correlation of HOMA IR with fasting insulin concentration in the SLE patients and SLE subgroups overall. However, HOMA -cells were positively correlated with HOMA IR and fasting insulin level, but negatively correlated with fasting glucose concentration in SLE patients overall. In conclusion, SLE patients, regardless of the presence of aCL and different disease activities, had a higher risk of insulin resistance and abnormal insulin secretion than age-matched healthy controls, based on fasting insulin concentration, HOMA IR, and HOMA -cells.Abbreviations HOMA Homeostasis model assessment - IGT Impaired glucose tolerance - IR Insulin resistance - NGT Normal glucose tolerance - SLE Systemic lupus erythematosus - SLEDAI SLE disease activity index