New Approach for Exploring Cerebral Functional Connectivity: Review of Cortico-cortical Evoked Potential

There has been a paradigm shift in the understanding of brain function. The intrinsic architecture of neuronal connections forms a key component of the cortical organization in our brain. Many imaging studies, such as noninvasive magnetic resonance imaging (MRI) studies, have now enabled visualization of the white matter fiber tracts interconnecting the functional cortical areas in the living brain. Although such a structural connectome is essential for understanding of cortical function, the anatomical information alone is not sufficient. Practically, few techniques allow the investigation of the excitatory and inhibitory mechanisms of the cortex in vivo in humans. Several attempts have been made to track neuronal connectivity by applying direct electrical stimuli to the brain in order to stimulate subdural and/or depth electrodes and record responses from the functionally connected cortex. In vivo single-pulse electrical stimulation (SPES) and/or cortico-cortical evoked potential (CCEP) were recently introduced to track various brain networks. This article reviews the concepts, significance, methods, mechanisms, limitations, and clinical applications of CCEP in the analysis of these dynamic connections.     

Sphincter of Oddi motor activity in patients with stones in gall-bladder, common bile duct or intrahepatic duct and the effect of morphine

Abstract Sphincter of Oddi phasic motor activity and common bile duct pressure were investigated in controls (seven patients) and in patients with gall-bladder stones (five patients), common bile duct stones (15 patients), or intrahepatic stones (13 patients). There were no significant differences in amplitude and frequency of the phasic activity or the common bile duct pressure between the controls and disease groups. Basal pressure of the phasic contraction, however, was significantly lower in patients with common bile duct or intrahepatic stones than in the controls or gall-bladder stone group. The administration of morphine, known to cause spasm of the sphincter of Oddi, increased the basal pressure and frequency of the phasic waves in all groups, while the amplitude remained unchanged. Response to morphine in patients with common bile duct or intrahepatic stones was similar to the controls. However, the basal pressure in these latter groups was lower than in the controls, even after stimulation by morphine. The high incidence of bacterial growth in bile from these patients hitherto reported may be attributable to ascending infection possibly resulting from the low basal pressure of the sphincter of Oddi.     

Recurrent pneumococcal meningitis in a patient with transient IgG subclass deficiency

We report the case of a 3 year old boy who exhibited recurrent serious infections with a transient imbalance of IgG subclass in the second year of life. He suffered from pneumococcal meningitis at 3 months, hepatitis at 9 months, and purulent arthritis at 11 months of age. The second episode of pneumococcal meningitis occurred at 14 months. Serum IgG level was normal for age. Low level of IgG2, undetectable level of IgG4 and negligible level of pneumococcus-specific IgG1-G2 antibodies were found. No other primary immunodeficiency was apparent. Serum IgG2-G4 levels but not pneumococcus-specific IgG1-G2 titers increased by the age of 30 months. At that time, he was inoculated with a polyvalent pneumococcal vaccine along with acellular diphtheria-pertussis-tetanus vaccine. He acquired the immunity against these agents, and had no episodic infections in the following 2 years. This observation stresses the existence of transient IgG subclass deficiency associated with delayed development of the anti-polysaccharide antibody response.     

Flecainide blocks the stimulatory effect of veratridine on slowly adapting pulmonary stretch receptors in anaesthetized rabbits without changing lung mechanics

We examined the responses of slowly adapting pulmonary stretch receptors (PSRs), total lung resistance (R_L) and dynamic lung compliance (C_dyn) to administered veratridine before and after pretreatment with atropine or flecainide in anaesthetized, artificially ventilated rabbits with bilateral vagotomy. Administration of veratridine (10 and 30 μg kg^-1) caused vigorous stimulation of PSRs, resulting in a tonic discharge of receptors during both inflation and deflation, but did not significantly alter either R_L or C_dyn. The veratridine-induced PSR stimulation became more prominent, as the dose of this alkaloid was increased. Pretreatment with atropine (1 or 2 mg kg^-1) had no significant effect on the excitatory response of PSRs to veratridine. The veratridine induced PSR stimulation was inhibited by treatment with flecainide (1, 2 and 3 mg kg^-1), a sodium channel blocker, and this inhibition was dose-dependent. These results suggest that activation of PSRs following veratridine administration probably related to the increased influx of sodium ions into the receptive terminals but does not depend upon bronchoconstriction.     

Role of Polymorphonuclear Leucocytes and Oxygen-derived Free Radicals in the Formation of Gastric Lesions Induced by HCl/ethanol,and a Possible Mechanism of Protection by Anti-ulcer Polysaccharide

Abstract— This study examined the role of oxygen-derived free radicals in the pathogenesis of gastric mucosal lesions induced by HCl/ethanol. Superoxide dismutase, and catalase, and their combination reduced gastric lesion formation in mice. Gastric lesions were also reduced in mice treated with cyclophosphamide or anti-neutrophils, but not in mice treated with allopurinol or desulphated-carrageenan. Cobra venom factor did not reduce lesion formation. These results suggested that oxygen-free radicals may contribute to the formation of gastric mucosal lesions induced by HCl/ethanol, and that oxygen radicals were generated from neutrophils but not from xanthine oxidase. Anti-ulcer pectic polysaccharide, bupleuran 2IIc, which was recently isolated from the roots of Bupleurum falcatum L., showed potent inhibition of HCl/ethanol-induced gastric lesions in mice. Bupleuran 2IIc seemed to scavenge hydroxyl radical effectively. It was suggested that this anti-ulcer polysaccharide may provide protection to the gastric mucosa by scavenging oxygen-free radicals.     

A Study on Atypical Endoscopic Findings of Ulcerative Colitis: Longitudinal Ulcers,Mucosal Bridges and Red Spots

Abstract: One hundred and twenty-one ulcerative colitis patients diagnosed during the period of 1984 to 1988 were examined endoscopically on repeated occasions. Forty-six patients had total colitis, 56 had left-sided colitis, 15 had proctitis, and 4 were postoperative patients. When classified according to their macroscopic findings, 28 of the patients had the polyposis type of this disease, 88 had the atrophic type, and 5 had the mixed type. Longitudinal ulcers were found in 9 patients, occuring usually in the sigmoid colon. There was no pathological evidence of ischemic changes in these 9 patients. Mucosal bridges were found in 13 of the patients with total colitis, occurring somewhere from the cecum to the rectum. The mucosal bridges tended to be present during the mildly active stage of the disease. Red spots, which sometimes looked like vascular spiders, were found in 10 patients. The spots tended to appear before the disease went into the inactive stage. Histological observation showed regenerating vessels, sometimes with intramucosal bleeding; therefore the spots seemed to be intractable changes.     

Endoscopic Treatment of Hepatolithiasis in a Patient Undergoing Pancreatoduodenectomy

Abstract: Our subject was a 70-year-old woman who had undergone a pancreatoduodenectomy for cancer of the head of the pancreas 5 years prior to this study. She had prominent signs of jaundice and fever, which had started several days before admission, and which responded to intravenous antibiotic therapy. A peroral biliary fiberscope (XQ-20, Olympus) was introduced into the afferent loop to the anastomosis of the bile tract, and an endoscopic cholangiograpy revealed hepatolithiasis. Endoscopic balloon dilatation was performed and the stones were removed using the balloon. Endoscopic therapy for hepatolithiasis was successfully performed after a pancreatoduodenectomy.