P300 and the thought disorder factor extracted by factor-analytic procedures in schizophrenia.

BACKGROUND: In order to clarify the clinical significance of P300 as a biologic marker that can reflect schizophrenic symptomatology, many previous studies have evaluated the relationship of P300 with the symptoms on the basis of a positive/negative dichotomy, but yielded inconsistent conclusions. Such a dichotomy has been criticized as being too reductionistic. Recently, most studies with factor-analytic procedures have extracted some symptom factors outside this dichotomy. Therefore, it is important to examine associations of P300 with the symptom factors extracted by these statistical analyses. METHODS: In the present study, the amplitudes of P300 were measured by using an auditory oddball paradigm for 73 schizophrenics whose psychopathology was assessed with the Positive and Negative Syndrome Scale (PANSS). RESULTS: The principal component analysis of the PANSS items revealed five factors labeled the thought disorder, negative, hostile/excitable, delusional/hallucinatory, and depressive factors. The score for the thought disorder factor correlated negatively with the amplitude of P300 recorded at Pz T5, and T6, but that for the other factors did not. CONCLUSIONS: These findings suggest that the reduction of P300 amplitudes recorded at the midline parietal and bilateral temporoparietal regions may be one of the electrophysiologic indices representing the thought disorder clinically observed in schizophrenia.

Simultaneous observation of regional cerebral blood flow and event-related potential during performance of an auditory task.

Reduced amplitude of the P300 component has been reported consistently in patients with neurological and psychiatric disorders. It is unclear, however, how such patients' cognitive dysfunction is related to their P300 abnormality. Further basic knowledge regarding neural substrates for P300 generation is required for gaining an understanding of the pathological significance of the P300 amplitude reduction. To determine the brain structures involved in P300 generation, we observed the event-related potential and the regional cerebral blood flow (rCBF) in 10 normal subjects performing an oddball discrimination of pure tones. The rCBF value was assessed quantitatively with the aid of single photon emission computed tomography using technetium-99m hexamethylpropylene amine oxime. During the task performance, significant activation was observed in the posterior superior temporal and inferior parietal regions of the right hemisphere. In addition, positive correlation of the task-related increase in rCBF with the simultaneously recorded P300 amplitude was observed in the right but not the left posterior superior temporal region. These findings indicate that activation of the right non-verbal auditory area might modulate P300 generation during pure-tone discrimination.

Laparoscopic closure for perforation of the sigmoid colon by endoscopic linear stapler.

Immediate open surgery has been recommended for the management of perforation during colonoscopic examination. Laparoscopic closure for perforation of the sigmoid colon caused by diagnostic colonoscopy is described. The perforation site was identified in the antimesenteric border of the sigmoid colon by laparoscopic survey, and four ports were inserted in the lower abdomen. The margin of the perforation was lifted by two graspers, and the defect was completely closed using an endoscopic linear stapler. The patient recovered quickly without any associated complications. Postoperative barium enema showed no stenosis or leakage. This method is less invasive and allows earlier recovery of patients with colonic perforation.

Radiofrequency hyperthermia for malignant liver tumors: the clinical results of seven patients.

BACKGROUND/AIMS: Since 1991, we have performed radiofrequency hyperthermia combined with chemotherapy preliminarily for malignant liver tumors. MATERIALS AND METHODS: We were using the BSD-1000 Annular phased array system and monitored intratumoral, skin superficial and intrarectal temperature. The subjects consisted of five patients with hepatocellular carcinoma and two with metastatic liver cancer. All seven patients received therapy from once to five times, with a mean frequency of 3.3 +/- 1.3 (S.D) times. RESULTS: The maximum intratumoral temperature was 42.2 +/- 1.0 (S.D.) degrees of centigrade, the length that intratumoral temperature reached 41 degrees of centigrade was 17.1 +/- 6.9 (S.D.) minutes and the length that intratumoral temperature kept above 41 degrees of centigrade was 30.8 +/- 7.5 (S.D.) minutes. The skin superficial and intrarectal temperature were 39.3 +/- 1.1 (S.D.) degrees of centigrade, 40.3 +/- 1.8 (S.D.) degrees of centigrade, respectively. The most common complaints were nausea (28%) and dyspnea (14%). CONCLUSIONS: No severe side effects were observed, although one case experienced an abdominal skin burn. We thus found that it was possible to heat deepseated liver tumors safely.

Lipiodolization for unresectable hepatocellular carcinoma: an analysis of 205 patients using univariate and multivariate analysis.

Since 1982 we have developed and successfully performed lipiodolization on 205 patients with unresectable hepatocellular carcinoma. The 1-, 2-, 3-, 4-, and 5-year survival rates were 55.6%, 31.7%, 16.3%, 8.7%, and 2.9%, respectively, while the median survival was 413 days, and 20 patients survived longer than 3 years after the first lipiodolization. Our study demonstrated that the factors for a comparatively good prognosis were as follows: patient older than 50 years, nodular type hepatocellular carcinoma < 5 cm in diameter, negative tumor invasion of portal vein, < 10 intrahepatic metastases, serum alpha-fetoprotein level < 400 ng/ml, and Okuda stage I. Lipiodolization did not cure hepatocellular carcinoma. It did, however, in this study, achieve a prolongation of the patient's survival.