Correlation between P50 suppression and psychometric schizotypy among non-clinical Japanese subjects.

The link between P50 suppression and psychometric schizotypy was previously reported in non-clinical English-speaking subjects; however, whether a similar relationship exists within a different ethnic sample is unknown. Furthermore, whether such a relationship can also be accounted for by such basic personality characteristics as extraversion or neuroticism has not yet been reported. In the present study, we investigated the correlations of P50 suppression with psychometric schizotypy, and with extraversion or neuroticism among non-clinical Japanese. Subjects were 34 healthy volunteers. The auditory P50 potential was obtained using a paired stimulus paradigm. Psychometric schizotypy was assessed using schizotypal personality questionnaire (SPQ). Extraversion and neuroticism were assessed using Maudsley personality inventory (MPI). P50 suppression correlated not only with total SPQ score, but also with extraversion and with neuroticism. However, the partial correlation analysis revealed a significant partial correlation of P50 suppression with SPQ when controlled for extraversion or neuroticism, and a non-significant partial correlation of P50 suppression with extraversion or neuroticism when controlled for SPQ. When subjects were divided into two subgroups according to the mean SPQ score, the degree of P50 suppression was lower in the high than in the low SPQ scorers. Our results indicate that P50 suppression is one of the neurobiological substrates underlying psychometric schizotypy, and that this relationship cannot be accounted for by measures of extraversion or neuroticism.

Increased rate of P300 latency prolongation with age in drug-naive and first episode schizophrenia.

OBJECTIVE: Previous studies have found an increased rate of P300 latency prolongation with age in medicated chronic patients with schizophrenia, suggesting a pathological neurodegenerative process. In this study, we investigated whether this abnormality was identified in drug-naive and first episode patients with schizophrenia. METHODS: P300 from auditory stimuli was recorded from 20 drug naive and first episode male patients with schizophrenia and compared with 23 age and handedness matched healthy male controls. The relationship of P300 latency and P300 amplitude to age in each group was evaluated using polynomial regression analyses. RESULTS: Reduction of P300 amplitude was significant in drug-naive and first episode schizophrenia patients. P300 amplitude negatively correlated with age in schizophrenia patients but not in controls. Although the prolongation of P300 latency with age was observed in both groups, the regression slope for P300 latency with age was significantly steeper in patients with schizophrenia than in normal controls. Significant overall curvilinear correlations with age were also found for P300 latency and amplitude in patients with schizophrenia, and for P300 latency in normal controls. CONCLUSIONS: The greater increase in P300 latency and reduction in P300 amplitude with age may be a primary neuropathological effect of schizophrenia. SIGNIFICANCE: This study suggests that neurodegenerative processes are involved in the etiology of schizophrenia.

The N200 abnormalities of auditory event-related potentials in patients with panic disorder.

Cognitive impairment in patients with panic disorder (PD) has been studied using event-related potentials (ERPs). However, previous studies obtained ERP data only at a few scalp sites, and seldom investigated N200 measurements from the difference waveforms. In the present study, auditory ERPs were recorded at 16 scalp sites during an active discrimination task of oddball paradigm. Fourteen PD patients (8 with agoraphobia; 6 without agoraphobia) were compared with 14 sex- and age-matched control subjects. For the nontarget waveforms, P2 amplitude was reduced in PD patients. For the target waveforms, a topographical difference between female PD patients and female controls was found for N200 amplitude, which attenuated in female PD patients over the parietal area. Two subcomponents of N200, N2a and N2b, were measured from the difference waveforms. A significant group difference was found for N2b amplitude, which reduced in PD patients compared with unaffected control subjects. It is suggested that N2b reduction reflects an abnormally controlled processing of stimulus information in PD.

Abnormalities of auditory P300 cortical current density in patients with schizophrenia using high density recording.

While P300 current density analysis has been performed in schizophrenic patients, the event-related potential data have never been obtained using a high density recording, nor have their cortical images been well demonstrated. In this study, the auditory P300 elicited by an oddball paradigm was recorded using a high density recording system of 128 channels. Thirteen male patients who met DSM-IV criteria for schizophrenia were compared with 20 healthy male controls. The cortical current density analysis of low resolution electromagnetic tomography (LORETA) was applied to the P300 component, and this resulted in the values of 6222 current density points over the surface of a cortex model. The inter-group difference of P300 current density was assessed using a point-by-point comparison by t-test. While the normal controls demonstrated the cortical activation of bilateral frontal, temporal and parietal cortex during the oddball paradigm, visual inspection suggested that in the schizophrenic patients these areas were less activated. The inter-group significance of P300 current density was dominant over the left hemisphere, and particularly over the left prefrontal area. It is concluded that the LORETA current density analysis localizes the neural activity from the cortical fronto-temporo-parietal network as the neural substrates of the scalp recorded P300. The dysfunction of such a network, especially over the left hemisphere, possibly subserves the scalp recorded P300 abnormality in schizophrenia.

Analysis of microsatellite instability, K-ras gene mutation and p53 protein overexpression in intrahepatic cholangiocarcinoma.

BACKGROUND/AIMS: Genetic alterations are considered to play an important role in both the carcinogenesis and biological behavior of human malignancies. However, the clinical implications of intrahepatic cholangiocarcinoma are poorly understood. We investigated the microsatellite instability, K-ras gene mutations and p53 protein overexpression and their correlation with clinicopathological features to elucidate the clinical implications of genetic alterations in intrahepatic cholangiocarcinoma. METHODOLOGY: In twenty-three cases of surgically treated intrahepatic cholangiocarcinoma, microsatellite instability was examined by a PCR-SSCP analysis and K-ras gene mutation by a PCR-RFLP analysis, p53 protein overexpression by immunohistochemistry. We evaluated the correlation between genetic alterations and clinicopathological features. RESULTS: Microsatellite instability was observed in one case (4.7%), K-ras gene mutation in 9 (39.1%) and positive staining for p53 protein in 5 (21.7%). The incidence of K-ras gene mutations in hilar type intrahepatic cholangiocarcinoma (6 of 8, 75.0%) was significantly higher than that in peripheral type intrahepatic cholangiocarcinoma (3 of 15, 20.0%) (P < 0.05). Furthermore, the incidence of K-ras gene mutations in patients with lymph node metastasis (58.3%) tended to be higher than that in patients without lymph node metastasis (18.2%). The patients with K-ras gene mutations showed a statistically significant worse survival rate than those without such mutations (P < 0.05). No statistically significant correlations were observed between the p53 overexpression and clinicopathological features. CONCLUSIONS: These data suggest that K-ras gene mutations may be involved in the carcinogenesis of intrahepatic cholangiocarcinoma, especially in hilar type intrahepatic cholangiocarcinoma, and thus may be correlated with aggressive biological behavior.

Microsatellite instability in patients with gastric remnant cancer.

BACKGROUND: About 2% of patients who undergo partial distal gastrectomy for gastroduodenal diseases develop gastric remnant cancer 10 to 30 years after the gastrectomy. It is important in clinical practice to determine a molecular marker to identify patients susceptible to gastric remnant cancer.METHODS: We investigated nine gastric remnant cancers (from nine individuals who had gastrectomies for primary gastric cancer or gastroduodenal ulcer) for microsatellite instability (MSI) at six loci, using the polymerase chain reaction (PCR). A control group of ten patients with sporadic gastric cancers in the upper third of the stomach was also similarly analyzed.RESULTS: MSI was demonstrated in eight of nine cancers from the individuals who had had primary gastric cancer or gastroduodenal ulcer (88.9%) compared with two of ten cancers from the individuals with sporadic gastric cancer in the upper third of the stomach (20%).CONCLUSION: These results suggest that one or more MSI is associated with remnant gastric cancer after gastrectomy.

Barrett's adenocarcinoma associated with acquired eventration of the diaphragm.

We report a rare case of Barrett's adenocarcinoma asso-ciated with acquired eventration of the diaphragm in a 71-year-old woman. She initially developed dysphagia and epigastric discomfort in May, 1997. On July 9, she was referred to our Department of Surgery at the Ryukyus University Hospital for thorough examination and treatment. Esophageal adenocarcinoma and eventration of the diaphragm were revealed by exhaustive examinations, including chest X-ray, computed tomography, and magnetic resonance imaging, and proximal gastrectomy with reconstruction of jejunal interposition was performed, on August 8. Histologically, the tumor revealed that the adenocarcinoma arose from short-segment Barrett's esophagus (SSBE). It thus appears that eventration of the diaphragm may induce SSBE and Barrett's adenocarcinoma. We therefore recommend that periodic examinations of the esophagus and stomach be performed in patients with eventration of the diaphragm. Barrett's adenocarcinoma associated with acquired eventration of the diaphragm is reported. Patients with eventration of the diaphragm should undergo periodic examinations of the esophagus and stomach.