An increasing amount of research has suggested that Internet addiction is associated with abnormalities in the dopaminergic brain system. We hypothesized that Internet addiction would be associated with reduced levels of dopaminergic receptor availability in the striatum compared with controls. To test this hypothesis, a radiolabeled ligand [C]raclopride and positron emission tomography was used to assess dopamine D2 receptor binding potential in men with and without Internet addiction. Consistent with our prediction, individuals with Internet addiction showed reduced levels of dopamine D2 receptor availability in subdivisions of the striatum including the bilateral dorsal caudate and right putamen. This finding contributes to the understanding of neurobiological mechanism of Internet addiction.

Extraversion is a core personality trait associated with individual differences in reward sensitivity and has been linked to the dopaminergic brain system. We investigated whether dopaminergic receptor availability in the striatum was directly associated with individual differences in extraversion using the high-affinity radiotracer [¹⁸F]fallypride and PET. Seventeen healthy male and female participants completed an [¹⁸F]fallypride PET scan at rest. Extraversion was assessed using the revised Eysenck Personality Questionnaire. Dopamine receptor availability in predefined striatal regions of interest was assessed as [¹⁸F]fallypride binding potential using a reference tissue model for [¹⁸F]fallypride. Both region of interest and voxel-based whole-brain analyses showed that extraversion was significantly correlated with dopaminergic receptor availability in the striatum bilaterally. This finding contributes to our understanding of the dopaminergic neural mechanisms underlying individual differences in extraversion.

Purpose:Recently, diagnosis of stage 1 gastric cancer has increased in number and prognosis is excellent when proper treatment is done. However, some patients have recurrence and their prognosis is poor. Thus, we investigated the risk factors of recurrence in stage 1 gastric cancer patients. Methods: From January 2004 to December 2008, a total of 1,241 number patients were operated on for stage 1 gastric cancer at the Department of General Surgery, Kosin University Gospel Hospital. We reviewed the characteristics of all patients retrospectively and compared them to recurred group (n=24) and non-recurred group (n=1,114). We analyzed the risk factors associated with recurrence. Results: Twenty-four patients with stage 1 gastric cancer were recurred after radical gastrectomy. Recurrence rate was 2.05%. The most common pattern of recurrence was hematogenous (41.7%), and lymphatic (20.8%), peritoneal seeding (16.7%), combined form (12.5%), and locoregional (8.3%). Five-year survival rate was 50.08% of recurrence group. Of clinicopathological factors, depth of invasion, lymph node metastasis, lymphatic involvement and tumor marker were statistically significant between recurred and other group.

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