Specific metabolites in the medial prefrontal cortex are associated with the neurocognitive deficits in schizophrenia: a preliminary study.

We measured brain metabolites in the medial prefrontal cortex of 19 schizophrenic patients and 18 healthy controls by 3 T proton magnetic resonance spectroscopy ((1)H MRS), and examined the relationship between prefrontal cortex-related neurocognitive functions and brain metabolites in the medial prefrontal cortex. The patients with schizophrenia exhibited deficits on the verbal fluency, Wisconsin card sorting test (WCST), trail making test, Stroop test and digit span distraction test (DSDT), but not on the Iowa gambling test. The patients showed statistical significant changes in the ratio of glutamine/glutamate, the ratio of N-acetyl-l-aspartate (NAA)/glycerophosphorylcholine plus phosphorylcholine (GPC+PC) and the levels of taurine in the medial prefrontal cortex compared with normal controls. Furthermore, we found significant correlations of the ratio of glutamine/glutamate with WCST and DSDT scores, the ratio of NAA/(GPC+PC) with verbal fluency and WCST scores, and the levels of taurine with scores on the Stroop test and Trail making test A among the participants. The ratios of NAA/(GPC+PC) and (GPC+PC)/(Cr+PCr) had significant relationships with the duration of untreated psychosis of the schizophrenic patients. The glutamine/glutamate ratio and levels of taurine were significantly related to the duration of illness of the patients. These data suggest that specific metabolites of the medial prefrontal cortex are associated with the neurocognitive deficits in schizophrenia.

Measurement of the electrical properties of human skin and the variation among subjects with certain skin conditions.

In this study the dielectric properties are reported for human skin tissues over the frequency range 1-450 MHz at 36 degrees C. Healthy volunteers, collagen disease patients and dialysis patients are studied in order to investigate, primarily, the variability among (1) different regions of one individual, (2) the same region among different individuals and (3) skin conditions due to diseases. Considerable differences exist among the skin dielectric properties obtained from different regions of one individual body. Although region dependence is observed, larger variability is found even in the same skin region among individuals.

Negative correlation between brain glutathione level and negative symptoms in schizophrenia: a 3T 1H-MRS study.

BACKGROUND: Glutathione (GSH), a major intracellular antioxidant, plays a role in NMDA receptor-mediated neurotransmission, which is involved in the pathophysiology of schizophrenia. In the present study, we aimed to investigate whether GSH levels are altered in the posterior medial frontal cortex of schizophrenic patients. Furthermore, we examined correlations between GSH levels and clinical variables in patients. METHODS AND FINDINGS: Twenty schizophrenia patients and 16 age- and gender-matched normal controls were enrolled to examine the levels of GSH in the posterior medial frontal cortex by using 3T SIGNA EXCITE (1)H-MRS with the spectral editing technique, MEGA-PRESS. Clinical variables of patients were assessed by the Global Assessment of Functioning (GAF), Scale for the Assessment of Negative Symptoms (SANS), Brief Psychiatric Rating Scale (BPRS), Drug-Induced Extra-Pyramidal Symptoms Scale (DIEPSS), and five cognitive performance tests (Word Fluency Test, Stroop Test, Trail Making Test, Wisconsin Card Sorting Test and Digit Span Distractibility Test). Levels of GSH in the posterior medial frontal cortex of schizophrenic patients were not different from those of normal controls. However, we found a significant negative correlation between GSH levels and the severity of negative symptoms (SANS total score and negative symptom subscore on BPRS) in patients. There were no correlations between brain GSH levels and scores on any cognitive performance test except Trail Making Test part A. CONCLUSION: These results suggest that GSH levels in the posterior medial frontal cortex may be related to negative symptoms in schizophrenic patients. Therefore, agents that increase GSH levels in the brain could be potential therapeutic drugs for negative symptoms in schizophrenia.

Quantitative magnetic resonance spectroscopy of schizophrenia: relationship between decreased N-acetylaspartate and frontal lobe dysfunction.

Numerous studies using proton magnetic resonance spectroscopy (1H-MRS) have detected signal changes in schizophrenia. However, most studies investigated relative concentrations such as N-acetylaspartate/creatine plus phosphocreatine (NAA/Cre) and choline-containing compounds/creatine plus phosphocreatine (Cho/Cre), and individual metabolite concentrations have not been clarified. Using absolute quantification measurement of 1H-MRS, the aim of the present paper was to demonstrate the changes in metabolite concentrations in the frontal lobe of patients with chronic schizophrenia. The 1H-MRS was performed in the left frontal lobe in 14 patients with schizophrenia and in 13 healthy comparison subjects. Individual MRS peak concentration was quantified based on a frequency-domain fitting program: LCModel. The scores on the Positive and Negative Symptoms Scale and Wisconsin Card Sorting Test were used for clinical assessment. The NAA concentration was reduced in schizophrenic patients (average, 7.94 mmol/L, t=2.28, P<0.05) compared with healthy subjects (average=8.45 mmol/L) while choline, creatine or NAA/Cre ratio did not show any differences. The reduction in NAA concentration had a significant correlation with the severity of negative symptoms (r=-0.536, P<0.05) and poor performance in Wisconsin Card Sorting Test (r=-0.544, P<0.05). Using quantitative MRS, decreased NAA concentration was confirmed in the left frontal lobe of schizophrenic patients and was demonstrated to be correlated with negative symptoms and cognitive dysfunction in schizophrenia.

Development of a dielectric equivalent gel for better impedance matching for human skin.

It would be useful to develop a tissue equivalent gel to improve the uniformity of the electromagnetic field in the human body, and for making a tissue equivalent dielectric human phantom. In this study, solid type, water based gelatin-honey gels were developed which have the electrical characteristics of skin tissue. It was demonstrated that a stable and homogeneous gel, with a relative dielectric constant epsilon ' chosen from desired ranges found in skin, can be made for 200-400 MHz.