Oxidant signalling in carcinogenesis: a commentary

It is becoming increasingly evident that reactive oxygen species (ROS) act at different stages of carcinogenesis, and thus play multiple roles in oncogenesis. In addition to being mutagenic and initiating tumors, ROS or carcinogens that result in ROS generation may affect tumor promotion and progression through varied effects on growth promoting, growth inhibitory, or apoptotic signaling pathways.     

Risperidone augmentation decreases rapid eye movement sleep and decreases wake in treatment-resistant depressed patients

BACKGROUND: The atypical antipsychotic agent risperidone has beneficial effects on mood in patients with schizophrenia. This study aimed to assess whether risperidone produced typical antidepressant-like effects in the polysomnogram of healthy subjects and in depressed patients unresponsive to antidepressant medication. METHOD: We measured the effect of a single dose of risperidone (1 mg) on the polysomnogram of 8 healthy volunteers in a placebo-controlled, double-blind, crossover design. We also measured the effects of open-label risperidone treatment (0.5-1.0 mg daily) on the polysomnogram of 8 patients meeting DSM-IV criteria for major depressive disorder who had received therapeutic doses of an antidepressant with an unsatisfactory response. Sleep was recorded at baseline and following 2 weeks of risperidone addition. RESULTS: In the healthy volunteers, risperidone significantly decreased rapid eye movement (REM) sleep (p =.04). After 2 weeks of risperidone treatment, depressed patients had significantly less wake (p =.02) and REM sleep (p =.02). Scores on depression rating scales for the depressed patients showed a significant decline (p <.05). CONCLUSION: Risperidone administration decreases REM sleep in both healthy volunteers and medication-resistant depressed patients, an action characteristic of conventional antidepressant medication. In depressed patients, risperidone also decreased wake. The utility of risperidone as an augmentation agent in depressed patients merits controlled study.     

A proposed approach for modelling health-care systems for understanding

Discrete event simulation (DES) application is not as widely perceived as being useful for problem solving in the health-care arena as in other application areas. Suggests that this might be due to the way DES is applied in health-care modelling, as it follows a traditionally based-on-engineering approach This may not be a problem in itself; however, health-care systems are often complex in that they involve multiple decision-makers and thus understanding and communication between the various stakeholders are potentially problematic. Thinks that problem understanding and efficient communication tools largely contribute to the solution; consequently, proposes a modelling approach to enhance stakeholder understanding and communication. The approach is based on participation of stakeholders; it is also iterative rather than step-based. To demonstrate this approach, gives an example, aiming to show how this approach has been used successfully to facilitate the understanding process, concluding that involving stakeholders throughout not only helps them to understand their problem better, but also enables them to more fully appreciate the findings resulting from the model. This approach thus serves usefully to enrich the communication between the stakeholders.     

Effects of tryptophan depletion on the performance of an iterated Prisoner's Dilemma game in healthy adults.

Adaptive social behavior often necessitates choosing to cooperate with others for long-term gains at the expense of noncooperative behaviors giving larger immediate gains. Although little is know about the neural substrates that support cooperative over noncooperative behaviors, recent research has shown that mutually cooperative behavior in the context of a mixed-motive game, the Prisoner's Dilemma (PD), is associated with increased neural activity within reinforcement circuitry. Other research attests to a role for serotonin in the modulation of social behavior and in reward processing. In this study, we used a within-subject, crossover, double-blind design to investigate performance of an iterated, sequential PD game for monetary reward by healthy human adult participants following ingestion of an amino-acid drink that either did (T+) or did not (T-) contain l-tryptophan. Tryptophan depletion produced significant reductions in the level of cooperation shown by participants when playing the game on the first, but not the second, study days. This effect was accompanied by a significantly diminished probability of cooperative responding given previous mutually cooperative behavior. These data suggest that serotonin plays a significant role in the acquisition of socially cooperative behavior in human adult participants, and suggest novel hypotheses concerning the serotonergic modulation of reward information in socially cooperative behavior in both health and psychiatric illness.     

Lamotrigine in the treatment of bipolar disorder

Lamotrigine is a novel anticonvulsant agent that has recently been introduced as a long-term treatment in bipolar disorder. Its role in the treatment of epilepsy is based on its actions to decrease ion channel conductance and antagonise glutamatergic function. Therefore, it has a mode of action unlike other agents used on a long-term basis in mood disorders. The evidence for efficacy is stronger for the prevention of depressive, rather than manic, episodes. The pivotal trials are in bipolar I disorder, but there is interest in its actions in patients with bipolar II and spectrum conditions. Its efficacy in other psychiatric conditions remains to be properly established. It is well tolerated and, with careful prescribing, the incidence of rash occurs no more than with placebo; however this is still a concern. Although usually well tolerated, headache, insomnia and drowsiness are probably the most common side effects.