持久饥饿对涡虫转氨酶、磷酸酶、蛋白水解酶和增殖细胞核抗原的影响

目的探讨持久饥饿对涡虫转氨酶、磷酸酶、蛋白水解酶和增殖细胞核抗原(PCNA)的影响。方法采用全自动生化分析仪测定转氨酶的活性变化,用复性电泳技术分析磷酸酶和蛋白水解酶的变化,用半定量RT-PCR技术分析PCNA mRNA的表达变化。结果饥饿过程中谷丙转氨酶和谷草转氨酶的活性显著升高,是对照水平的10倍以上,恢复喂食后逐渐降低到正常水平;碱性磷酸酶(ALP)的活性在饥饿过程中明显减弱,而酸性磷酸酶(ACP)活性却显著增强;受饥饿影响,140kD和40kD蛋白水解酶的活性均明显增加;然而饥饿过程中PCNA的表达没有明显变化,说明饥饿对该基因的影响很小。结论持久饥饿对涡虫的生理和生化代谢有重要影响,酶活性的变化反应了涡虫适应持久饥饿的能量代谢变化。     

Psychoneuroendocrinology of anorexia nervosa

It is suggested that the symptoms of anorexia nervosa are physiological responses to starvation. There is no evidence of a neural or non-neural dysfunction that predisposes women for anorexia nervosa and the endocrine and psychological consequences of starvation are reversed once patients have re-learnt how to eat and regained a normal body weight. Because variability in the supply of food may be a common evolutionary condition, it is more likely that body weight is variable than constant in normal circumstances. The role of the neuroendocrine system in times of feast and famine is to allow the individual to adopt behavioral strategies as needed rather than maintaining body weight homeostasis. Treatment of anorexic patients should aim at reducing their high level of physical activity in order to facilitate eating.     

Gustatory and olfactory sensitivity in patients with anorexia and bulimia in the course of treatment

Background

The majority of studies on taste and smell in eating disorders have revealed several alterations of olfactory or gustatory functions. Aim of this prospective study was to employ detailed olfactory and gustatory testing in female subjects of three homogenous groups - anorexia nervosa, bulimia nervosa and healthy controls - and to look at the effects of treatment on these measures.

Methods

Sixteen hospitalized female patients with anorexia (restricting type, mean age [M] = 24.5 years), 24 female patients with bulimia (purging type, M = 24.3 years) as well as 23 healthy controls (M = 24.5 years) received olfactory (“Sniffin’ Sticks”) and gustatory testing (“Taste Strips”). Group differences in olfactory and gustatory sensitivity, body mass index (BMI), the Beck depression inventory, the eating attitudes test (EAT), and the influence of therapy on gustatory and olfactory function were investigated.

Results

(1) Group differences were present for odor discrimination and overall olfactory function with anorexic patients having the lowest scores. (2) Regarding taste function, controls scored higher than patients with anorexia. (3) At admission small but significant correlations were found between overall olfactory function and body weight (r₆₃ = 0.35), BMI (r₆₃ = 0.37), and EAT score (r₆₃ = −0.27). Similarly, (4) the taste test score correlated significantly with body weight (r₆₃ = 0.48), and BMI (r₆₃ = 0.45). Finally, (5) at discharge overall olfactory and gustatory function were significantly higher compared to admission in anorexic patients.

Conclusions

As compared to healthy controls and bulimic patients our results show lowered olfactory and gustatory sensitivities in anorexic patients that improved with increasing BMI and decreasing eating pathology in the course of treatment.     

The effects of high fat diets on the blood-brain barrier transport of leptin: failure or adaptation?

Leptin is a pluripotent regulatory protein secreted by fat and exerts many effects through the CNS. Interpretation of the characteristics by which it crosses the blood-brain barrier (BBB) supports the view that leptin most potently signals the brain at serum levels well below those associated with the current definition of ideal body weight. This fits with the perspective that low serum levels of leptin are a signal to brain that a sufficient store of calories are available for the organism to expend energy for efforts unrelated to acquisition of calories. This would explain why low serum levels of leptin are permissive in many of the non-feeding actions of leptin, such as enhancing CNS-mediated immune function, memory, bone growth, reproduction, breathing, and neurogenesis. Triglycerides inhibit the transport of leptin across the BBB and so could be key in the onset of the peripheral leptin resistance, which is a hallmark of obesity. These results explain the paradox of why obesity should induce resistance to an anorectic: hypertriglyceridemia also occurs with starvation and we postulate that triglyceride-induced resistance to leptin transport across the BBB initially evolved to limit the signal of an anorectic to the brain during starvation.     

饥饿诱导下小鼠成骨细胞自噬与凋亡相互作用研究

目的:探讨饥饿条件下自噬与凋亡在小鼠成骨细胞中的发生情况与相互关系。方法:培养初代MC3T3-E1小鼠成骨细胞系,将其分为饥饿诱导组与3-甲基腺素(3-MA)预处理饥饿诱导组。其中,饥饿诱导组采用单纯饥饿诱导法,用厄尔氏平衡盐溶液(earle’s balanced salt solution,EBSS)培养1 h、2 h、3 h、4 h、5 h、6 h。3-MA是一种特异性自噬抑制剂,在3-MA预处理饥饿诱导组中,正常培养的小鼠成骨细胞加入3-MA预处理1 h后,再用EBSS平衡盐溶液培养1 h、2 h、3 h、4 h、5 h、6 h。应用透射电子显微镜观察饥饿诱导组小鼠成骨细胞自噬与凋亡的形态学变化,应用Western blot免疫印迹法和Annexin V-FITC/PI双标记流式细胞术检测小鼠成骨细胞中自噬相关蛋白LC3,凋亡相关蛋白caspase 3表达水平的变化。结果:透射电镜结果显示单纯饥饿诱导条件下,细胞在2 h前以自噬为主,2 h后以凋亡为主,并随着时间的延长,凋亡水平逐渐增高。Western blot免疫印迹法结果显示与饥饿诱导组相比,3-MA预处理饥饿诱导组的LC3转化水平在1 h、2 h、3 h、4 h、5 h、6 h都出产生了明显的下降趋势(P<0.05);caspase 3蛋白表达水平在1 h、2 h、3 h和4 h增高(P<0.05),但0 h、5 h和6 h无差异(P>0.05)。Annexin V-FITC/PI双标记流式细胞术检测结果和单纯饥饿诱导组相比,3-MA预处理组仅在1 h、2 h、3 h和4 h促进了细胞凋亡(P<0.05),而并未影响到0 h、5 h和6 h的细胞凋亡(P>0.05)。结论:饥饿发生后,小鼠成骨细胞的自噬作用通过降低caspase 3的活化水平,在细胞饥饿2 h前拮抗凋亡作用,随着饥饿时间的不断延长,细胞自噬的表达水平在3 h和4 h时不断下降,自噬对细胞的保护不断降低,最终走向凋亡,此时自噬对凋亡的发生将不再有任何作用。     

mRNA expression patterns for GH, PRL, SL, IGF-I and IGF-II during altered feeding status in rabbitfish, Siganus guttatus

Feeding time is a major synchronizer of many physiological rhythms in many organisms. Alteration in the nutritional status, specifically fasting, also affects the secretion rhythms of growth hormone (GH) and insulin-like growth factor-I (IGF-I). In this study, we investigated whether the expression patterns for the mRNAs of GH, prolactin (PRL) and somatolactin (SL) in the pituitary gland, and insulin-like growth factor I and II (IGF-I and IGF-II) in the liver of juvenile rabbitfish (Siganus guttatus) follow a rhythm according to feeding time and whether these hormone rhythms changes with starvation. Hormone mRNA levels were determined by real time PCR. The daily expression pattern for the mRNAs of GH, PRL and SL was not altered whether food was given in the morning (10:00 h) or in the afternoon (15:00 h). The daily GH mRNA expression pattern, however, was affected when food was not available for 3 days. In contrast, the daily expression pattern for IGF-I mRNA reaches its peak at roughly 5-6h after feeding. This pattern, however, was not observed with IGF-II mRNA. During 15-day starvation, GH mRNA levels in starved fish were significantly higher than the control fish starting on the 9th day of starvation until day 15. The levels returned to normal after re-feeding. In contrast to GH, PRL mRNA levels in starved fish were significantly lower than the control group starting on the 6th day of starvation until 3 days after re-feeding. SL mRNA levels were not significantly different between the control and starved group at anytime during the experiment. Both IGF-I and IGF-II mRNA levels in starved group were significantly higher than the control fish on the 3rd and 6th day of starvation. mRNA levels of both IGF-I and II in the starved fish decreased starting on the 9th day of starvation. While IGF-I mRNA levels in the starved group continued to decrease as starvation progressed, IGF-II mRNA levels were not significantly different from the control during the rest of the starvation period. The results indicate that aside from GH and IGF-I, PRL and IGF-II are likewise involved in starvation in rabbitfish.     

SWCNTs induced autophagic cell death in human bronchial epithelial cells

Carbon nanotubes are being actively introduced in electronics, computer science, aerospace, and other industries. Thus, the urgent need for toxicological studies on CNTs is mounting. In this study, we investigated the alterations in cellular response with morphological changes induced by single-walled carbon nanotubes (SWCNTs) in BEAS-2B cells, a human bronchial epithelial cell line. At 24 h after exposure, SWCNTs rapidly decreased ATP production and cell viability as well a slight increase in the number of cells in the subG1 and G1 phases. In addition, SWCNTs increased the expression of superoxide dismutase (SOD)-1, but not SOD-2, and the number of cells generating ROS. The concentration of Cu and Zn ions also increased in a dose-dependent manner in cells exposed to SWCNTs. SWCNTs significantly enhanced the release of nitric oxide, interleukin (IL)-6, and IL-8 and up-regulated the expression of chemokine- and cytokine-related genes. Furthermore, the levels of autophagy-related genes, especially the DRAM1 gene, and the autophagosome formation-related proteins, were clearly up-regulated together with an increase of autophagosome-like vacuoles. Based on these results, we suggest that SWCNTs induce autophagic cell death through mitochondrial dysfunction and cytosolic damage in human bronchial epithelial cells.     

Redox-state and adenylic system in albino rat liver during experimental ketosis

Summary Ketosis was induced in Wistar rats in four experimental models: acute alloxan diabetes, insulin-treated alloxan diabetes, starvation and fat diet. The liver content of acetyl-CoA and of the reduced forms of the pairs lactate-pyruvate and malate-oxaloacetate increases. The NADH content decreases in acute alloxan diabetes and after a fat diet and increases in insulin-treated alloxan diabetes and in starvation. Both ATP and the ATP/ADP ratio decrease in all cases, except following a fat diet. There is no direct correlation between the degree of ketosis and the acetyl-CoA liver content.In this paper the following abbreviations are used: NAD and NADH: nicotinamide adenine nucleotide and its reduced form; ATP, ADP, AMP; 5adenosine(pyro)-triphosphate, -diphosphate and -monophosphate; E': redox potential.     

Blood pressure,hypertension and mortality from circulatory disease in men and women who survived the siege of Leningrad

The population of Leningrad suffered from severe starvation, cold and psychological stress during the siege in 1941–1944. We investigated long-term effects of the siege on cardiovascular risk factors and mortality in surviving men and women. 3905 men born 1916–1935 and 1729 women born 1910–1940, resident in St Petersburg (formerly Leningrad) between 1975 and 1982, of whom a third experienced the siege as children, adolescents or young adults, were examined for cardiovascular risk factors in 1975–1977 and 1980–1982 respectively and followed till end 2005. Effects of siege exposure on blood pressure, lipids, body size, and mortality were studied in multivariate analysis stratified by gender and period of birth, adjusted for age, smoking, alcohol and social characteristics. Women who were 6–8 years-old and men who were 9–15 years-old at the peak of starvation had higher systolic blood pressure compared to unexposed subjects born during the same period of birth (fully adjusted difference 8.8, 95% CI: 0.1–17.5 mm Hg in women and 2.9, 95% CI: 0.7–5.0 mm Hg in men). Mean height of women who were exposed to siege as children appeared to be greater than that of unexposed women. Higher mortality from ischaemic heart disease and cerebrovascular disease was noted in men exposed at age 6–8 and 9–15, respectively. The experience of severe stress and starvation in childhood and puberty may have long-term effects on systolic blood pressure and circulatory disease in surviving men and women with potential gender differences in the effect of siege experienced at pre-pubertal age.     

In situ localization of preprogalanin mRNA in the goldfish brain and changes in its expression during feeding and starvation

In this paper, we report (i) the in situ localization, and (ii) meal time related and starvation induced changes in preprogalanin mRNA expression in the goldfish brain. The specific brain nuclei that express galanin mRNA are the area ventralis telencephali pars ventralis, nucleus preopticus periventricularis, nucleus lateralis tuberis, and the nucleus recessus lateralis. No changes in preprandial preprogalanin mRNA expression were found in the brain regions studied. No changes in postprandial preprogalanin mRNA expression were found compared to the preprandial levels. However, in unfed fish, a significant increase in preprogalanin mRNA expression was found in the telencephalon (1 and 3 h) and hypothalamus (3 h) after the scheduled feeding time. The postprandial preprogalanin mRNA expression in the telencephalon and hypothalamus of fed fish at 1 and 3 h were significantly lower than the mRNA expression levels in the unfed fish at the same time. Preprogalanin mRNA expression levels remain unaltered during 7 days of starvation. The presence of preprogalanin mRNA in brain nuclei involved in the regulation of food intake and pituitary hormone secretion suggests important physiological roles for galanin in goldfish.