Neural substrate of sound duration discrimination during an auditory sequence in the guinea pig primary auditory cortex

Mismatch negativity (MMN) is a negative component of event-related brain potentials elicited by stimulus transitions. Stimulus duration transition also elicits MMN (duration MMN), with a magnitude that is related to the degree of duration change and the discrimination ability. The neural substrates of duration MMN have not yet been investigated. We therefore studied how duration transitions in an auditory stimulus train are represented in neurons in the primary auditory cortex of anesthetized guinea pigs. Two types of neuronal responses to the context of changes in stimulus duration were found. One was a reduced response as the duration of the preceding stimulus was increased. Second was an enhancement of the late components of the response including sustained and offset responses at the duration transition. The former may be explained by the previously proposed two-tone suppression, which is dependent on the preceding stimulus duration. The latter is likely to be caused by stimulus-specific adaptation that could be a possible neural generator of duration MMN.     

Exercise-Induced Ventricular Arrhythmia after Repair of Tetralogy of Fallot

Treadmill exercise electrocardiography (TE) was recorded in 50 patients to evaluate the incidence of exercise-induced ventricular arrhythmias (VAs) in a group of patients who underwent corrective surgery of tetralogy of Fallot (TF) more than four years previously. The results of rhythm evaluation were correlated with cardiac catheterization data as well as clinical information such as the age at surgery and the interval from surgery. Of the 50 patients tested, ventricular premature contraction (VPC) was confirmed in 12 patients (24%) on TE, while five patients (10%) demonstrated VPC on the standard ECG. The interval from surgery was significantly longer in those patients with VA (Group 1) than those without VA (Group 11) on TE (p<0.05). There was no significant difference of the age at corrective surgery between the two groups. In group I, the preoperative hemoglobin level was higher (p<0.05) and the right ventricular ejection fraction was lower (p<0.01). Exercise-induced VAs are closely related to the length of period after surgery and the depressed right ventricular function.     

Renal cell carcinoma producing α-fetoprotein (AFP) with a unique lectins-affinity profile

Renal cell carcinoma (RCC) producing α-fetoprotein (AFP) is a rare entity and merely 7 cases have been reported so far. The present case, a 71-year-old woman, showed a high serum AFP level of 204 ng/ml. The RCC of the autopsied right kidney consisted mainly of spindle-shaped or bizarre sarco-matous tumor cells. AFP was immunolocalized only in the concomitant clear cell component. Concanavalin A (Con A)-nonadsorption rate of serum AFP was 42%, which was an intermediate value between those of yolk sac tumors and metastatic liver carcinomas. Lens culinalis agglutinin (LCA)-affinity study of the patient's AFP showed an unknown peak X, which was eluted between the known peaks 2 and 3. These results suggest a certain structural alteration in carbohydrate moieties of the AFP derived from this RCC. A review of the clincopathologic features of 8 patients with AFP-producing RCC was made to understand the pathophysiology of AFP-producing neoplasms. © Wiley-Liss, Inc.     

Predictive value of blood flow in the gastric tube in anastomotic insufficiency after thoracic esophagectomy

Anastomotic insufficiency is considered to be one of the most serious complications associated with esophageal reconstruction. The purposes of this study were to identify (1) the relationship between anastomotic insufficiency and tissue blood flow (TBF) in the gastric tube in the perioperative period, and (2) the effects of intravenous prostaglandin E1 (PGE1) on TBF in the gastric tube. The study group consisted of 44 patients who were to undergo esophagectomy for esophageal cancer. Intraoperative and postoperative TBF on the serosal side of the gastric tube were measured by laser-Doppler tissue blood flowmetry. The TBF of the Leakage(+) group (n = 5) was poorer than that of the Leakage(?) group (n = 39) during the intraoperative and postoperative periods. There was a significant difference in TBF between the two groups at postoperative day (POD) 3. There was a tendency in the PGE1(+) group (n = 18) to exhibit richer blood flow through the anastomosis than the PGE1(?) group (n = 26), intraoperatively, but the difference was not significant. Two of five Leakage(+) cases were also in the PGE1(+) group. There was no relationship between intraoperative medication with PGE1 and incidence of leakage. The TBF of three-field lymph node dissection and reconstruction of the retrosternal route group (n = 21) was poorer than that of the two-field lymph-node dissection and reconstruction of the posterior mediastinal route group (n = 23). The TBF in the gastric tube after esophagectomy may be a predictor of anastomotic insufficiency. However, PGE1 treatment in the intraoperative period alone is not effective in preventing anastomotic insufficiency.     

Association of dopamine transporter loss in the orbitofrontal and dorsolateral prefrontal cortices with methamphetamine-related psychiatric symptoms

OBJECTIVE: The authors examined dopamine transporter density in the orbitofrontal cortex, dorsolateral prefrontal cortex, and amygdala in methamphetamine users and assessed the relationship of these measures to the subjects' clinical characteristics. METHOD: Positron emission tomography with [(11)C]WIN 35,428 was used to examine the regions of interest in 11 methamphetamine users and nine healthy comparison subjects. Psychiatric symptoms were evaluated with the Brief Psychiatric Rating Scale. RESULTS: Dopamine transporter density in the three regions studied was significantly lower in the methamphetamine users than in the comparison subjects. The lower dopamine transporter density in the orbitofrontal and dorsolateral prefrontal cortex was significantly correlated with the duration of methamphetamine use and the severity of psychiatric symptoms. CONCLUSIONS: Chronic methamphetamine use may cause dopamine transporter reduction in the orbitofrontal cortex, dorsolateral prefrontal cortex, and amygdala in the brain. Psychiatric symptoms in methamphetamine users may be attributable to the decrease in dopamine transporter density in the orbitofrontal cortex and the dorsolateral prefrontal cortex.     

Increased oxidative stress with elevated serum thioredoxin level in patients with coronary spastic angina

BACKGROUND: Increased oxidative stress has been implicated in the pathogenesis of coronary vasospasm. Thioredoxin (TRX) is a redox-active protein that is known to be induced by oxidative stress. HYPOTHESIS: The serum TRX level may be high in patients with coronary vasospasm. METHODS: The serum TRX level was determined using an enzyme-linked immunosorbent assay in 21 patients with the active stage of coronary spastic angina (CSA), in 18 patients with the inactive stage of CSA (iCSA), in 24 control subjects without coronary artery disease (Control), and in 20 patients with stable effort angina (SEA). RESULTS: Serum TRX levels (mean +/- standard deviation ng/ml) were significantly higher in CSA (64 +/- 44) than in iCSA (28 +/- 26), in Control (34 +/- 15), and in SEA (36 +/- 16). In contrast, serum alpha-tocopherol levels (mg/g lipids) were significantly lower in CSA (2.8 +/- 0.7) than in Control (4.0 +/- 1.2) and in SEA (3.2 +/- 0.4). Current smoking was significantly more prevalent in CSA (76%) than in any of the other groups. No significant correlation was found between the serum level of TRX and alpha-tocopherol in the study subjects. In nine patients with CSA, the serum TRX level decreased (93 +/- 41 --> 41 +/- 35 ng/ml) and the alpha-tocopherol level increased (2.7 +/- 0.6 --> 3.2 +/- 0.7 mg/g lipids) significantly under medication with calcium entry blockers after an at least 3-month angina-free period. CONCLUSIONS: Patients with coronary spastic angina had a higher serum TRX level associated with a lower serum level of antioxidant vitamin E, with redox equilibrium appearing to be related to the disease activity of coronary vasospasm in these patients. Oxidative stress may be related to the genesis of coronary vasospasm.     

Age differences in phosphodiesterase type-IV and its functional response to dopamine D1 receptor modulation in the living brain: a PET study in conscious monkeys

The present study demonstrated the age-related changes in the striatal dopamine D1 receptor binding and its related cAMP second-messenger system in the living brains of conscious young (6.4 +/- 1.8 years old) and aged (19.5 +/- 3.3 years old) monkeys (Macaca mulatta) using positron emission tomography (PET). For quantitative analysis of D1 receptors, [11C]SCH23390 was used and phosphodiesterase type-IV (PDE-IV) activity, as an index of cAMP system, was estimated by two scans with R- and S-[11C]rolipram. Significant age-related decreases in D1 receptor binding were observed in the striatum and frontal cortex. Analysis of uptake of R- and S-[11C]rolipram indicated age-related decreases in PDE-IV activity showing 22.0 and 25.2% decreases in the striatum and frontal cortex, respectively, while no significant changes were observed in the cerebellum. With systemic preadministration of the dopamine D1 receptor antagonist SCH23390 (0.2, 0.6, and 2 mg/kg), the PDE-IV activities in the striatum and frontal cortex were dose-dependently suppressed in both age groups. However, the degree of suppression by SCH23390 was more marked in young than in aged monkeys. These results demonstrate that the striatal cAMP second-messenger system activity as well as its functional response to dopamine D1 antagonist showed age-related impairment in the brain.     

Glut-1 glucose transporter expression in esophageal squamous cell carcinoma is associated with tumor aggressiveness

BACKGROUND: Glucose transporter (Glut) proteins, which are membrane proteins responsible for the transport of glucose across cellular membranes, have six forms. To further elucidate the role of Glut-1 expression in esophageal squamous cell carcinoma, we examined the expression of Glut-1 protein immunohistochemically. MATERIALS AND METHODS: Immunohistochemical expression of Glut-1 was examined in surgically resected tissues from 95 patients with esophageal squamous cell carcinoma. RESULTS: Of the 95 esophageal carcinomas, 91 (95.8%) had some Glut-1 immunostaining in the membranes of the cancer cells. Positive staining (> 30% of cancer cells showing Glut-1 expression) was observed in 49 (51.6%) of the cases. Comparison of Glut-1 expression and clinicopathological characteristics in the 95 patients with esophageal cancer revealed significant associations between Glut-1 expression and tumor status (p < 0.001), lymph node status (p < 0.05), metastatic status (p < 0.01), and pathological stage (p < 0.001). The survival rates of patients with Glut-1-positive tumors were significantly lower than those of patients with Glut-1-negative tumors (log-rank p < 0.05). CONCLUSION: In conclusion, the level of Glut-1 expression may be a useful marker that can provide information on tumor aggressiveness and prognosis in patients with esophageal squamous cell carcinoma.     

Cortical functional abnormality assessed by auditory-evoked magnetic fields and therapeutic approach in patients with chronic dizziness

A long-lasting dizzy sensation is a common complaint in elderly subjects. The pathogenesis and effective treatment of such chronic dizziness (CD), however, have not yet been fully elucidated because of lack of methods for evaluating this sensation. On the basis of assumption that CD may be attributable partly to cortical functional abnormality, we attempted to estimate the function of auditory cortex by measurements of auditory-evoked magnetic fields (AEFs). Magnetic field signals in the parieto-temporal cortex were evoked by 1000-Hz tone-burst with 90-dB normal hearing level sounds, and the highest-amplitude magnetic waveforms at approximately 100-ms (N100m) were analyzed as electrical current arrows in normal subjects (n=11), patients with CD (n=27) and patients with cerebral infarction but no dizzy sensation (n=9). In the normal subjects, the current arrows pointed to a nearly straight line with small directional distortion as indicated by a rotation-degree parameter, dI(rot) of 1.59+/-0.46. In 17 of 27 CD patients, the directions of current arrows were markedly distorted showing abnormally high dI(rot) values greater than 2.50 (the mean plus two standard deviations of normal values) and disclosed a clockwise or counter-clockwise rotation in either side or both sides of parieto-temporal cortex. In all the patients with cerebral infarction, the current arrows exhibited the similar pattern as the normal subjects. None of them exhibited abnormally high dI(rot) values. We hypothesized that the rotational abnormality may be caused by abnormal neuronal excitation, since non-evoked magnetic fields in temporal lobe epilepsy demonstrated the similar current rotational abnormality as reported previously. Seven CD patients were treated with anticonvulsants, and four showed remarkable amelioration of dizzy sensation. In all the four patients with symptomatic amelioration, the disappearance of rotational abnormality in AEFs or the tendency towards disappearance was observed following symptomatic amelioration. The results of the present study suggest that the auditory center may contribute to the maintenance of equilibrium, and its dysfunction may lead to the development of CD. AEFs measurements may make it possible to evaluate the functional abnormality of auditory center and may be useful for studying the pathophysiology and treatment of CD.