Pharmacological interactions between serotonin and dopamine on behavior in the squirrel monkey

 The behavioral effects of GBR 12909, a selective dopamine uptake inhibitor, were determined in squirrel monkeys trained to respond under a fixed-interval (FI) schedule of stimulus termination and a second-order schedule of IV drug self-administration. Intermediate doses of GBR 12909 increased FI response rate markedly, and the highest dose decreased response rate below control values. The 5HT uptake inhibitors, alaproclate and fluoxetine, and the 5HT agonist, quipazine, attenuated the behavioral-stimulant effects of GBR 12909, whereas the 5HT_2A/2C antagonist, ritanserin, enhanced the behavioral-stimulant effects of the lowest dose. GBR 12909 reliably maintained self-administration, and ritanserin increased response rate maintained by the highest dose. The dopamine agonist, quinpirole, increased FI response rate in only one of three subjects, and ritanserin enhanced the behavioral-stimulant effects of quinpirole in that subject. The dopamine agonist, apomorphine, only decreased FI response rate, and ritanserin did not alter its behavioral effects. The pharmacological profile of GBR 12909 administered alone and in combination with selective 5HT drugs in the present study was similar to that obtained previously with cocaine, further demonstrating that 5HT can reliably modulate the behavioral effects of psychomotor stimulants with prominent dopaminergic actions. Received: 9 July 1996 / Final version: 22 November 1996     

Neurochemical mechanisms mediating the behavioral and cognitive effects of nicotine

Data are reviewed, largely from experiments in the authors'laboratory, that suggest three modes of action of systemic nicotine in producing three different types of effect upon behavior and cognitive function. (1) Preexposure of a stimulus without consequence makes it harder subsequently to form associations to that stimulus, a form of selective attention known as latent inhibition. Latent inhibition is blocked by nicotine, an effect that is apparently mediated by a nicotine-induced increase in dopamine release in the nucleus accumbens. (2) A single dose of nicotine proactively increases the partial reinforcement extinction effect measured several weeks later: that is, resistance to extinction is decreased by nicotine in animals that have been trained on a continuous reinforcement schedule, and increased in animals trained on a partial reinforcement schedule. This effect appears to be due to increased synthesis of tyrosine hydroxylase in the cell bodies of noradrenergic neurons in the locus coeruleus, followed by axonal transport to the hippocampus and increased synthesis and release of noradrenaline in that structure. (3) Nicotine improves vigilance in animals with cognitive deficits due to destruction of the forebrain cholinergic projection system, either as a consequence of excitotoxic lesions of the nuclei of origin of this system or after prolonged alcohol consumption; and also in human subjects with Alzheimer's disease (in which this system undergoes degeneration). This effect is most likely due to an action at denervated cholinergic synapses in the hippocampus and neocortex. © 1994 Wiley-Liss, Inc.     

Surface behavior of axolemma monolayers: Physico-chemical characterization and use as supported planar membranes for cultured Schwann cells

The axolemma membrane forms a stable and reproducible monomolecular layer at the air-aqueous interface. The major lipids and proteins are present in this monolayer in molar ratios similar to the original membrane. Acetylcholinesterase and Na-K-ATPase activities are preserved in the monolayer to levels of 64% and 25%, respectively. The total lipid fraction forms a homogeneously mixed phase. The presence of proteins in the monolayer introduces surface inhomogeneties. Among other features, this is revealed by the presence of two values of lateral pressure at which the monolayer shows partial or total collapse: a broad partial collapse at surface pressures between 13 to 30 mN/m and a sharp collapse point at 46 mN/m. The average molecular areas, the broad collapse point, and the variation of the surface potential per molecule suggest the relocation of protein components at surface pressures between 13 to 30 mN/m. The behavior is consistent with the extrusion and exposure of proteins toward the aqueous medium that depends on the lateral pressure. Schwann cells grown on coverslips coated with axolemma monolayers at 13 mN/m (beginning of the broad collapse) and 34 mN/m (above the broad collapse) recognize the difference in the surface organization of axolemma caused by the lateral pressure which affects their proliferation, morphology, and spatial pattern of organization. Our results show for the first time that response of Schwann cells depends on the intermolecular organization of the axolemma surface with which they interact. These results suggest that the local expression of putative surface molecules of axolemma that may mediate membrane recognition and the signalling of morphological and proliferative changes can be modulated by long range supramolecular properties. © 1993 Wiley-Liss, Inc.     

再生丝素/NMMO·H2O溶液的流变性能

使用N-甲基吗啉-N-氧化物的水合物(NMMO·H2O)作为再生丝素的溶剂.可以得到w=0.10～0.25的再生丝素/NMMO·H2O溶液.研究了再生丝素/NMMO·H2O溶液流变性能,讨论了剪切速率、温度和溶液中的再生丝素的含量对再生丝素/NMMO·H2O溶液流变性能的影响.     

云南罗平医院PM调查的分析与对策

文章以云南罗平医院为研究对象,调查了65名一般员工和21名科主任级中层领导,使用PM量表对该医院的高层及中层领导行为进行评估,对情景因素与领导行为的内在联系进行探讨,并提出改进对策。目的是了解员工需求,促进人力资源合理配置,从而提高医院的管理水平。     

Fetal behavior in multifetal pregnancies studied by four-dimensional sonography

Rapid improvements in the capacity of data processing due to technological breakthroughs in processor engineering is the basis of spatial imaging. Spatial imaging is the main benefit of three-dimensional sonography and it is used for visualization of fetal anatomy in three dimensions. Modern machines are capable of performing spatial imaging in near real time, called four-dimensional sonography. Four-dimensional sonography in multifetal pregnancies can be used for detection and evaluation of intertwin contacts, because it allows simultaneous visualization of both fetuses and assessment of their motor activity. The main benefits of four-dimensional sonography include: accurate recognition of an isolated motor activity of a single fetus; distinguishing between spontaneous and stimulated motor activity; and spatial visualization of the intertwin area.     

A neurotrophic model for stress-related mood disorders.

There is a growing body of evidence demonstrating that stress decreases the expression of brain-derived neurotrophic factor (BDNF) in limbic structures that control mood and that antidepressant treatment reverses or blocks the effects of stress. Decreased levels of BDNF, as well as other neurotrophic factors, could contribute to the atrophy of certain limbic structures, including the hippocampus and prefrontal cortex that has been observed in depressed subjects. Conversely, the neurotrophic actions of antidepressants could reverse neuronal atrophy and cell loss and thereby contribute to the therapeutic actions of these treatments. This review provides a critical examination of the neurotrophic hypothesis of depression that has evolved from this work, including analysis of preclinical cellular (adult neurogenesis) and behavioral models of depression and antidepressant actions, as well as clinical neuroimaging and postmortem studies. Although there are some limitations, the results of these studies are consistent with the hypothesis that decreased expression of BDNF and possibly other growth factors contributes to depression and that upregulation of BDNF plays a role in the actions of antidepressant treatment.     

Parenting children with and without developmental delay: the role of self-mastery

Background While parenting behaviours have direct effects on children’s behavioural outcomes, other, more distal factors also may be shaping the way a mother handles parenting responsibilities. Dispositional factors are likely to be a major influence in determining how one parents. Although researchers have studied the relationships among maternal dispositional factors, parenting, and child behaviours, few studies have examined these relationships when the child is at developmental risk. Children with developmental delays evidence elevated clinical level behaviour problems, so this group is of primary interest in the search for precursors to psychopathology. The present study examined how the maternal dispositional trait of self‐mastery, as well as supportive and non‐supportive parenting, relate to behaviour problems in young children with and without developmental delay. Method Participants were 225 families, drawn from Central Pennsylvania and Southern California. The children, all aged 4 years, were classified as delayed (n = 97) or non‐delayed (n = 128). The Self‐Mastery Scale measured perceived level of control over life events. The Coping with Children’s Negative Emotions Scale measured different ways parents perceive themselves as reacting to their children’s distress and negative affect. The Child Behavior Checklist assessed children’s behaviour problems. Results Delayed condition mothers reported significantly more child behaviour problems than non‐delayed condition mothers; the two conditions did not differ in self‐mastery, supportive parenting, or non‐supportive parenting. Self‐mastery, non‐ supportive parenting reactions, and child behaviour problems all related significantly to one another. For the sample as a whole and within the delayed condition, the association between self‐mastery and child behaviour problems was partially mediated by non‐supportive parenting reactions, although self‐mastery was still significantly associated with problem behaviour. In the non‐delayed condition, although significant relationships also were found among the variables of interest, non‐supportive parenting did not have a significant main or mediation effect. Delay status moderated the relationship between negative parenting reactions and child behaviour problems, assessed by the Child Behavior Checklist Total and Internalizing scores. When mothers displayed low levels of non‐supportive reactions, children in the delayed and non‐delayed groups had similar levels of total problem behaviour. However, when mothers were medium or high in non‐supportive reactions, children in the delayed group had much higher levels of problem behaviours than those in the non‐delayed group. Conclusions The present study extended research on parental dispositional factors and parenting by measuring self‐mastery as a global personality trait rather than measuring self‐efficacy related specifically to childrearing. Moreover, relationships were examined for both developmentally delayed and non‐delayed samples, allowing for a clearer understanding of the influences on problem behaviours in children with developmental delays. The findings support the view that parenting behaviours have a greater impact on children at developmental risk.     

The behavioral genetics of colony defense in honeybees: Genetic variability for guarding behavior

Guard honeybees stand at the entrance of colonies and facilitate the exclusion of nonnestmates from the colony. In this study, we examined the hypothesis that genetic variability among individuals in colonies might explain variability in guarding activity. To do this, we cross-fostered honey bees between colonies with high-defensive responses and colonies with low-defensive responses in alarm pheromone tests. Individuals from high-defensive colonies were more likely to guard in their own colonies (controls) than cross-fostered bees from low-defensive colonies. Cross-fostered high-defensive bees also were more likely to guard in low-defense colonies. These results support the hypothesis that interindividual differences in guarding behavior are at least partially under genetic control. A positive correlation between number of guards and response to alarm pheromone demonstrates a link between behaviorally separated components of the overall defensive response.This work was supported by NSF Grant BNS 8605604.     

Alcohol Use among Subcritically Injured Emergency Department Patients

Objectives: To determine the incidence of alcohol use in subcritically injured patients presenting to the ED, by using a saliva alcohol test (SAT) at ED triage during the ED initial assessment; to compare the incidence of alcohol use revealed by the SAT with documentation of alcohol use by ED nurses and emergency physicians (EPs) blinded to the SAT results; and to describe the demographics of the SAT-positive, subcritically injured population.
Methods: A blinded, prospective, observational evaluation of ED patients presenting with subcritical injuries was performed. The patients were tested for alcohol use with an SAT, and a subsequent record review was conducted for extraction of demographic data and evidence of documentation of alcohol use by ED nurses and EPs blinded to the SAT results.
Results: During the study. 791 subcritically injured patients had SATs performed. Twenty-one percent of these patients were found to be alcohol-positive by SAT. Either the ED nurse or the EP documented a clinical impression of alcohol use for 52% of the SAT-positive patients. There were higher SAT-positive rates among men (24%), victims of assault (47%), and patients arriving at night (41%).
Conclusions: While the SAT identified 21% of the subcritically injured patient population as alcohol-positive, ED nurse and EP documentation did not identify half of these alcohol-positive patients. Many of these patients may be at risk for additional injuries related to their drinking behavior.