Contraluminal transport of hexoses in the proximal convolution of the rat kidney in situ

In order to study contraluminal hexose transport, concentration and time-dependent influx of³H-2-deoxy-d-glucose from the interstitium into cortical tubular cells has been measured. The influx curves fit to a two parameter kinetics (K _m 1.3±0.2 mmol/l,J _max 0.67±0.16 pmol/s · cm) plus an additional diffusion term (withP=6·10^–8 cm²/s) and a distribution ratio extracellular to intracellular amount of 2-deoxy-d-glucose of 10.6. Since the extracellular to intracellular free water space as estimated from morphological data was 12, one must conclude that glucose has only free access to 1/3 of the cell water. The intracellularly accessible space was augmented when the tubules were preperfused for 10 s with hypotonic saline. Thereby an increase of the compartment into which diffusion occurs was revealed and a final rupture of this intracellular compartment at 1/4 isotonic solutions was observed. Total replacement of ions in the peritubular perfusate by mannitol did not change 2-deoxy-d-glucose influx, indicating that it is Na⁺-independent. By adding isotonic concentrations of the respective sugars to the capillary perfusate, three degrees of inhibition of 2-deoxy-d-glucose influx could be revealed: strong inhibition byd-glucose, methyl--d-glucoside,d-mannose, 3-O-methyl-d-glucose, 2-deoxy-d-galactose, methyl--d-galactoside and 6-deoxy-d-glucose, moderate inhibition byd-galactose,l-glucose,l-mannose andd-fructose, no or borderline inhibition by methyl -d-glucoside, 2-deoxy-methyl--d-galactoside, 1-thio--d-glucose, 1-thio--d-galactose, 5-thio--d-glucose, myo-inositol and mannitol. The contraluminal 2-deoxy-d-glucose influx was also inhibited by phloretin, chlormerodrin and preperfusion with cytochalasin B. Starvation as well as streptozotocin diabetes has no influence on contraluminal 2-deoxy-d-glucose transport. Thus, in contrast to the luminal hexose transport system the contraluminal system is Na⁺-independent, does not require on OH-group at C-atom 2, acceptsl-glucose and fructose, but not an -methyl group at C-atom 1.     

父母教养方式对3～9岁儿童自尊的影响

目的:考察父母教养方式对3～9岁儿童自尊的影响。方法:采用3～9岁儿童自尊教师评定问卷和父母教养方式问卷对700名儿童进行调查。结果:(1)民主性教养方式与自尊总分呈显著正相关(r=0.687,P=0.000)。(2)父母在不一致性、溺爱性教养方式上的评分与儿童自尊总体(F=7.544,P=0.001;F=3.650,P=0.026)以及重要感(F=6.578,P=0.001;F=3.781,P=0.023)、外表感(F=4.418,P=0.012)、自我胜任感(F=6.132,P=0.002;F=4.989,P=0.007)维度存在显著差异。结论:民主性教养方式有助于儿童形成高自尊;相反,对儿童越溺爱、教育方式越不一致,则容易使儿童形成低自尊。     

Responses of calves to acute stress: individual consistency and relations between behavioral and physiological measures

The present study examined the consistency over time of individual differences in behavioral and physiological responsiveness of calves to intuitively alarming test situations as well as the relationships between behavioral and physiological measures. Twenty Holstein Friesian heifer calves were individually subjected to the same series of two behavioral and two hypothalamo-pituitary-adrenocortical (HPA) axis reactivity tests at 3, 13 and 26 weeks of age. Novel environment (open field, OF) and novel object (NO) tests involved measurement of behavioral, plasma cortisol and heart rate responses. Plasma ACTH and/or cortisol response profiles were determined after administration of exogenous CRH and ACTH, respectively, in the HPA axis reactivity tests. Principal component analysis (PCA) was used to condense correlated measures within ages into principal components reflecting independent dimensions underlying the calves' reactivity. Cortisol responses to the OF and NO tests were positively associated with the latency to contact and negatively related to the time spent in contact with the NO. Individual differences in scores of a principal component summarizing this pattern of inter-correlations, as well as differences in separate measures of adrenocortical and behavioral reactivity in the OF and NO tests proved highly consistent over time. The cardiac response to confinement in a start box prior to the OF test was positively associated with the cortisol responses to the OF and NO tests at 26 weeks of age. HPA axis reactivity to ACTH or CRH was unrelated to adrenocortical and behavioral responses to novelty. These findings strongly suggest that the responsiveness of calves was mediated by stable individual characteristics. Correlated adrenocortical and behavioral responses to novelty may reflect underlying fearfulness, defining the individual's susceptibility to the elicitation of fear. Other independent characteristics mediating reactivity may include activity or coping style (related to locomotion) and underlying sociality (associated with vocalization).     

重点理工科高校大一新生焦虑状况及相关因素的研究

目的探讨重点理工科学校大一新生焦虑状况及相关因素,为进行针对性的干预提供依据。方法以广东某重点理工高校2007级的大一学生为研究对象,采用自行设计一般项目调查表、状态-特质焦虑量表（STAI）、匹兹堡睡眠质量指数量表（PSQI）、应付方式问卷进行测评。结果测查学生不论男女状态焦虑、特质焦虑分均显著高于地方常模;19.29%的学生睡眠质量较差;高状态焦虑组和高特质焦虑组解决问题、求助应付因子分均显著低于低状态焦虑组和低特质焦虑组,而自责、幻想、退避应付因子分则显著高于低状态焦虑组和低特质焦虑组;多元逐步回归分析说明,学生如常采用解决问题应付方式,在一定程度上可避免焦虑的产生,而睡眠质量差、采用自责应对方式则可加重焦虑水平。结论采取有效的认知应对策略其意义是使学生改变应激源,以使其变得威胁较小或变成挑战,把情绪基调训练成兴奋、期待和征服。     

单细胞凝胶电泳在遗传学损伤检测中的应用

单细胞凝胶电泳或彗星试验是在暴露人群中评价遗传学损伤的新式方法。这种分析可以快速的探测单一细胞中不同形式的DNA损伤，因此适于在暴露人群分析应用。本文将对彗星试验在临床研究及监测职业、环境、合理饮食、生活方式等对DNA损伤的危险性，以及在DNA损伤与修复研究中的应用等方面进行综述。     

An investigation of depotentiation of long-term potentiation in the CA1 region of the hippocampus

We have investigated long-term synaptic depression in the CA1 region of rat hippocampal slices. Prolonged low-frequency stimulation (LFS; 900 stimuli delivered at 2 Hz) of the Schaffer collateral-commissural pathway in naïve slices did not induce long-term depression (LTD) of synaptic transmission. However, if long-term potentiation (LTP) was firstly induced in the pathway then LFS generated an LTD-like effect (i.e. depotentiation of LTP). Depotentiation could be induced 2 h (the longest time studied) after the induction of LTP and was stable for the duration of the experiment (followed for up to 40 min). The induction of depotentiation was not blocked by the N-methyl-d-aspartate receptor antagonist d-2-amino-5-phosphonopentanoate, the L-type voltage-gated Ca²⁺ channel blocker nimodipine or the nitric oxide synthase inhibitor N-nitro-l-arginine. However, the magnitude of depotentiation was reversibly reduced, in a stereoselective manner, by the specific metabotropic glutamate receptor (mGluR) antagonist (+)--methyl-4-carboxyphenylglycine. These results show that prolonged low frequency stimulation can result in an mGluR-dependent depotentiation of LTP.     

警察的孤独感状况及其相关因素分析

目的：探讨警察的孤独感状况及其与心理健康、应对方式、社会支持的相关关系。方法：采用UCLA孤独量表，SCL-90症状自评量表，TCSQ特质应对方式问卷和PsSS领悟社会支持量表。对某市区公安分局884名公安干警进行调查。结果：派出所警察的孤独感明显高于机关干警。50—59岁组警察的孤独感明显低于其他年龄段。警察的孤独感与警种、积极应对、社会支持显著负相关，与消极应对及SCL-90得分显著正相关。年龄、婚姻状况、应对方式、社会支持以及SCL-90总分是影响警察孤独感的显著因素。结论：警察的孤独感程度较高。50岁以下的派出所民警，尤其是婚姻不稳定者是孤独敏感群体。警察的孤独感与应对方式、社会支持及心理健康水平相互影响。     

The Bücherer-Strecker synthesis of d- and l-(1-11C)tyrosine and the in vivo study of l-(1-11C)tyrosine in human brain using positron emission tomography

The synthesis of d-and l-(1-¹¹C)tyrosine, starting with ¹¹C-cyanide, is reported. dl-(1-¹¹C)Tyrosine was prepared by the Bücherer-Strecker reaction, from carrier added ¹¹C-cyanide with an incorporation of 80% in 20 min. The isolation of the pure d- and l-amino acid isomers from the enantiomeric mixture was accomplished within 15 min by preparative HPLC using a chiral stationary phase and a phosphate buffer as the mobile phase. Typically, the total synthesis time was 50 min (including purification) from end of trapping of ¹¹C-cyanide, with a radiochemical yield of d- and l-amino acid of 40%–60%. The d- and l-(1-¹¹C)tyrosine were both obtained optically pure, with a carrier added specific activity of 0.3–0.5 Ci/mmol and a radiochemical purity better than 99%. The ¹¹C labelled l-tyrosine was used in an in vivo study in the human brain using positron emission tomography (PET).     

Reversal of the reserpine-induced ptosis by l-threo-3,4-dihydroxy-phenylserine (l-threo-DOPS), a (−)-norepinephrine precursor,and its potentiation by imipramine or nialamide

Summary The effect of l-threo-DOPS on the reserpine-induced ptosis in mice and its modification by imipramine, a norepinephrine (NE) uptake inhibitor, or nialamide, a monoamineoxidase inhibitor, were studied.Intraperitoneal (i.p.) injection of l-threo-DOPS (800 mg/kg) significantly reduced the severity of the ptosis. This reversal of the ptosis by l-threo-DOPS was markedly potentiated by i.p. injection of either imipramine (2.5 mg/kg) or nialamide (30 mg/kg). Response to l-threo-DOPS was also significantly potentiated by intracerebroventricular (i.c.v.) injection of imipramine (10 g). On the other hand, this treatment with imipramine (10 g, i.c.v.) also significantly potentiated the reversal of the ptosis by NE (20 g, i.c.v.), but the reversal by the subcutaneous (s.c.) injection of NE (1 and 3 mg/kg) was not affected.Reserpine (5 mg/kg, i.p.) markedly decreased the brain content of NE in mice, whereas l-threo-DOPS (400 mg/kg, i.p.) slightly restored it. Moreover, by the pretreatment with nialamide (30 mg/kg, i.p.), l-threo-DOPS produced a significant increase in the brain content of NE in reserpinetreated mice.These results suggested that l-threo-DOPS was capable of reversing the reserpine-induced ptosis due to the formation, at least in part of (–)-NE at the synaptic sites of central noradrenergic neurons.     

Species differences in the relative analgesic potencies of some classical opiates and opioid peptides

The analgesic ED₅₀ values of some classical morphine congeners (morphine, methadone, fentanyl, azidomorphine) in the rat and mouse tail-flick tests were found to be similar. However, several synthetic derivatives of the natural enkephalins were more potent in mice than in rats. (These analogs contain d-amino acid in position 2 and d- or l-sulfonic (or phosphonic) acid residue in position 5). -Endorpin, d-Met², Pro⁵-enkephalinamide and two partial agonists showed intermediate interspecies relative potencies. According to the data obtained, similar opiate receptors might mediate the analgesic action of classical opiates in rats and in mice. However, the opiate receptors responsible for the antinociceptive effects of the above mentioned enkephalin analogues must be dissimilar in the two species examined. The results are discussed in terms of the role of - and -receptors in mediation of the analgesic effect induced by different types of opioids.