Abnormal Metabolic Connectivity in Rats at the Acute Stage of Ischemic Stroke

Stroke at the acute stage is a major cause of disability in adults, and is associated with dysfunction of brain networks. However, the mechanisms underlying changes in brain connectivity in stroke are far from fully elucidated. In the present study, we investigated brain metabolism and metabolic connectivity in a rat ischemic stroke model of middle cerebral artery occlusion （MCAO） at the acute stage using 18F-fluorodeoxyglucose positron emission tomography. Voxel-wise analysis showed decreased metabolism mainly in the ipsilesional hemi- sphere, and increased metabolism mainly in the contrale- sional cerebellum. We used further metabolic connectivity analysis to explore the brain metabolic network in MCAO. Compared to sham controls, rats with MCAO showed most significantly reduced nodal and local efficiency in the ipsilesional striatum. In addition, the MCAO group showed decreased metabolic central connection of the ipsilesional striatum with the ipsilesional cerebellum, ipsilesional hippocampus, and bilateral hypothalamus. Taken together, the present study demonstrated abnormal metabolic con- nectivity in rats at the acute stage of ischemic stroke, which might provide insight into clinical research.

An Automatic Method for Generating an Unbiased Intensity Normalizing Factor in Positron Emission Tomography Image Analysis After Stroke

Positron emission tomography （PET） imaging of functional metabolism has been widely used to investigate functional recovery and to evaluate therapeutic efficacy after stroke. The voxel intensity of a PET image is the most important indicator of cellular activity, but is affected by other factors such as the basal metabolic ratio of each subject. In order to locate dysfunctional regions accurately, intensity normalization by a scale factor is a prerequisite in the data analysis, for which the global mean value is most widely used. However, this is unsuitable for stroke studies. Alternatively, a specified scale factor calculated from a reference region is also used, comprising neither hyper- nor hypo-metabolic voxels. But there is no such recognized reference region for stroke studies. Therefore, we proposed a totally data-driven automatic method for unbiased scale factor generation. This factor was generated iteratively until the residual deviation of two adjacent scale factors was reduced by 〈 5%. Moreover, both simulated and real stroke data were used for evaluation, and these suggested that our proposed unbiased scale factor has better sensi- tivity and accuracy for stroke studies.

Distinct Roles of Dopamine Receptors in the Lateral Thalamus in a Rat Model of Decisional Impulsivity

The thalamus and central dopamine signaling have been shown to play important roles in high-level cognitive processes including impulsivity. However, little is known about the role of dopamine receptors in the thalamus in decisional impulsivity. In the present study,rats were tested using a delay discounting task and divided into three groups： high impulsivity（HI）, medium impulsivity（MI）, and low impulsivity（LI）. Subsequent in vivo voxel-based magnetic resonance imaging revealed that the HI rats displayed a markedly reduced density of gray matter in the lateral thalamus compared with the LI rats. In the MI rats, the dopamine D1 receptor antagonist SCH23390 or the D2 receptor antagonist eticlopride was microinjected into the lateral thalamus. SCH23390 significantly decreased their choice of a large, delayed reward and increased their omission of lever presses. In contrast,eticlopride increased the choice of a large, delayed reward but had no effect on the omissions. Together, our results indicate that the lateral thalamus is involved in decisional impulsivity, and dopamine D1 and D2 receptors in the lateral thalamus have distinct effects on decisional impulsive behaviors in rats. These results provide a new insightinto the dopamine signaling in the lateral thalamus in decisional impulsivity.

Determinants of self-management behaviors among pulmonary tuberculosis patients: a path analysis

Background Tuberculosis(TB)is one of the top 10 causes of death in the world.Since Directly Observed Therapy(DOT)as a core strategy for the global TB control are not applicable to all types of TB patients,and self-management of TB patients(SMTP)as a patient-centered supervision type is a supplement to DOT and can improve TB case management.However,the factors related to SMTP are complex and need more study.This study aimed at identifying the determinants of SMTP and examining the direct/indirect effects of these determinants.Methods The purposive sampling technique was used to select study sites and participants were recruited from the study sites by the consecutive sampling method.The PRECEDE model was used as the framework to analyze the determinants of SMTP.The responses of TB patients were acquired via a questionnaire survey for data collection.A Pearson correlation analysis was used to define the relationship between the predisposing,enabling,reinforcing factors with SMTP behaviors.A regression-based path analysis was used to determine the action paths of the predisposing,enabling,and reinforcing factors on SMTP behaviors.Results The predisposing(TB knowledge),enabling[health education and healthcare workers(HCWs)support],reinforcing factors(family support)had significant positive correlations with SMTP behaviors(P<0.05).The predisposing,enabling,reinforcing factors were positively correlated with each other(r=0.123‒0.918,P<0.05),except for family support and HCWs support.The predisposing factors(TB knowledge,β=0.330)and the enabling factors(HCWs support,β=0.437)had direct effects on SMTP behaviors.The enabling factors(health education and HCWs support)and the reinforcing factors(family support)had indirect effects on SMTP behaviors.Conclusions This study revealed the effects and action path of TB knowledge,health education,HCWs support,and family support on SMTP behaviors via a path analysis.Assessing patient’s needs for SMTP along with promoting effective TB health education and providing firm support from HCWs and family members are potential strategies to promote SMTP behaviors.