Extraversion and striatal dopaminergic receptor availability in young adults: an [18F]fallypride PET study.

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.

Reduced striatal dopamine D2 receptors in people with Internet addiction.

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.

[Outbreak of hepatitis by Orientia tsutsugamushi in the early years of the new millenium].

BACKGROUND/AIMS: Orientia -tsutsugamushi infection is an acute febrile disease due to the accidental transmission through human skin of forest dwelling vector Leptotrombidium larva. The authors observed liver dysfunctions in patients diagnosed with tsutsugamushi disease (Scrub typhus) in the past 3 years and report the data in the hope of bringing attention to this disease in the differential diagnosis of autumn-season hepatitis, especially of non-A, non-B and non-C hepatitis. METHODS: Medical records of 22 patients diagnosed with tsutsugamushi disease by the hemagglutinin method between October 2000 and November 2002 were reviewed. RESULTS: Female gender was dominant in the ratio of 3.4:1. Mean age was 56.4 +/- 2.6. Admission was between 23rd September and 15th November with the peak between mid October and early November. Fever, being the most common symptom, was observed in 21 cases, myalgia in 13, arthralgia in 12, chills in 6, and skin rash in 6. An incubation period of 7-9 days was most common (10 cases), 13-15 days (4), 10-12 days (3), within 3 days (3), and 4-6 days (2). Average ALT, AST and GGTP were increased to 93.2 +/- 17.3 IU/L (18 +/- 345 IU/L), 92.5 +/- 11.7 IU/L (34-255 IU/L) and 132.2 +/- 14.5 IU/L (19-251 IU/L), respectively, but total bilirubin was normal. All the patients improved with doxycycline therapy. CONCLUSIONS: Since it usually shows liver dysfunction, it is important to take Orientia tsutsugamushi into consideration in differential diagnosis of autumn-season, febrile hepatic disease.

[A case of fulminant hepatic failure in Wilson's disease combined with systemic lupus erythematosus].

Patients with systemic lupus erythematosus (SLE) have a chance of developing liver involvement in their lifetime. The main cause of liver involvement in SLE patients is previous treatment with hepatotoxic drugs or hepatotropic viral hepatitis. Wilson's disease is a hereditary disorder and is usually diagnosed in patients presenting either neuropsychiatric disorders or manifestations related to chronic liver disease. Fulminant hepatic failure as the initial manifestation of Wilson's disease is rare. The relationship between systemic lupus erythematosus and Wilson's disease has not been established. We report a case of a 12-year-old girl with SLE who presented fulminant hepatic failure as an initial manifestation of Wilson's disease. The diagnosis was established with decreased serum ceruloplasmin level and the presence of Kayser-Fleischer ring. We treated with repeated plasma exchange. Despite repeated plasma exchange she died of multi-organ failure on the 16th hospital day. Considering this case, Wilson's disease should be considered as a cause of fulminant hepatic failure, especially in juvenile age cases.