Premovement gating of somatosensory evoked potentials after tibial nerve stimulation

Somatosensory evoked potentials (SEPs) are attenuated or gated during movement. The mechanism for this includes both centrifugal gating of afferent input and competition with other afferents caused by the movement (peripheral gating). Using a paradigm in which the signal for triggering movement is the electric stimulus for SEPs, we studied the gating of SEPs after tibial nerve stimulation prior to foot movement, and compared it with that during counting task. Significant gating was found for P40 component, which distributed centrally and ipsilaterally to the side of the stimulation, whereas the contralateral N40 component showed no changes. Dissociated gating of P40 and N40 indicates multiple generators of these components, in contrast to the previous view of a single generator dipole projecting tangentially. Together with the previous findings in median SEPs, these gating phenomena should represent a general mechanism for sensori-motor integration in preparation for limb movement.     

Hypotensive effects of neuromedin U microinjected into the cardiovascular-related region of the rat nucleus tractus solitarius

Neuromedin U (NMU) is a brain-gut peptide with potent contractile effects on the uterus and smooth muscle. Intracerebroventricular injection of NMU reportedly decreased food intake and body-weight gain in the rat. We evaluated the effects of NMU delivered by microinjection into the rat nucleus tractus solitarius (NTS) on cardiovascular responses. At the concentrations used (5, 10 or 50 pmol), the intra-NTS injection of NMU in artificial cerebrospinal fluid produced a significant reduction in both the mean arterial pressure and heart rate. The hypotensive responses were dose dependent. Our findings suggest that NMU may act as a neurotransmitter or neuromodulative substance that causes excitation of neurons in the NTS and that it may play a role in cardiovascular regulation in vivo.     

Different brain kinetics of two sigma 1 receptor ligands, [3H](+)-pentazocine and [11C]SA4503, by P-glycoprotein modulation

We compared the brain kinetics of radiolabeled (+)-pentazocine and SA4503, which have a high and selective affinity for sigma(1) receptors. Brain uptake of [(11)C]SA4503 was high after intravenous injection followed by a gradual decrease in mice, whereas that of [(3)H](+)-pentazocine rapidly decreased. The brain uptake of the two radioligands was dose-dependently reduced, but the reduction of [(3)H](+)-pentazocine was found at higher doses. Percentages of the saturable binding of [(3)H](+)-pentazocine was much lower than that of [(11)C]SA4503. The brain uptake of [(3)H](+)-pentazocine was greatly blocked by SA4503 at a dose of 2 micromol/kg, while that of [(11)C]SA4503 was blocked by (+)-pentazocine at a dose of 20 micromol/kg and over. When mice were treated with cyclosporin A, a P-glycoprotein modulator, the uptake of [(3)H](+)-pentazocine was enhanced, but that of [(11)C]SA4503 was not. Under control and P-glycoprotein-modulated conditions, the brain uptake of both radioligands was reduced by haloperidol, another representative sigma receptor ligand, to a different extent. We concluded that the P-glycoprotein modulation resulted in the different brain kinetics of the two radioligands. The radiolabeled SA4503 is suitable as an in vivo probe, but radiolabeled (+)-pentazocine is not.     

Prediction of Japanese cedar pollen emission in a snowy area--surveillance in Hirosaki City

Japanese cedar is the most common pollinosis allergen in Japan. Predictions of total pollen counts and the first 2 or more days of the Japanese cedar pollen season are beneficial to patients. We developed predictive methods for those 2 factors in Hirosaki. We conducted an atmospheric Japanese cedar pollen survey from 1996 to 2002 in Hirosaki and compared yearly data with the male flowering index counted in 50 cedar trees in the preceding autumn. The male flowering index correlated highly positively with total cedar pollen counts in regression analysis, indicating its usefulness in predicting total pollen counts. Although the number of days from January 1 to the first day of continuous pollen emission showed no correlation with the cumulative maximum temperature during these days, the number of days from the day of first detection of pollen emission (minimum of 1 particle per sq. cm) to the first day of continuous pollen emission correlated highly with the cumulative maximum temperature and cumulative amount of snowfall on these days, suggesting that it is possible to predict the first day of continuous pollen emission by the cumulated daily maximum temperature after the day of first detection of pollen emission.     

Mastoid obliteration by BMP-2/collagen composites: an experimental study using tissue engineering

PURPOSE: Several materials have been used in the application of mastoid cavity obliteration during surgery for cholesteatoma; however, nothing has won universal acceptance. Through the advancement of tissue engineering, bone morphogenetic protein-2 (BMP-2)/collagen composites have been elucidated as inducers of heterogenic bone formation. This study was performed to investigate whether these composites are potentially obliteration materials for use in the mastoid cavity by using an animal experimental study. MATERIALS AND METHODS: The composites were implanted in the rat mastoid to investigate whether new bone would be tissue engineered in the mastoid and, if so, whether the newly formed bone was stable. The composites were examined histologically over a 24-week period. RESULTS: The composites implanted in the rat mastoid were able to tissue engineer new bone, and the newly formed bone was stable as assessed histologically, with almost normal bone structure, that was not resorbed during the 24-week period. Adverse immunological reactions were not found during our observation. CONCLUSIONS: Bone that was tissue engineered by the BMP-2/collagen composites was stable as assessed by histological examination and persisted in the rat mastoid. The present study shows that the composites have the potential to become real materials for use in mastoid obliteration.     

Malignant fibrous histiocytoma of the parotid gland

Primary malignant fibrous histiocytoma (MFH) arising in a major salivary gland is rare. We encountered a case of MFH affecting the parotid gland. The patient was a 54-year-old man diagnosed as having pleomorphic type of MFH after extended total parotidectomy. Examination of the resected specimen revealed the tumor had not been completely removed. Accordingly treatment consisted in the resection of MFH and radiotherapy in combination with chemotherapy using carboplatin (CBDCA). This postoperative therapy was effective in controlling the growth of the remaining tumor tissue. As the patient showed no signs of local recurrence and distant metastasis for 5 years, plastic surgery was performed to improve the serious deformation of the face with a free anterolateral thigh flap. Our literature review yielded 17 cases of parotid MFH and the 2-year survival rate was 33%.     

A comparison of heart rate during rest and work in shift workers with different work styles

To determine if the type of work performed should be considered in research on shift work and cardiovascular disease, we compared the heart rates, total number of steps walked, and blood pressures of 12 shift workers on the same rotating 3-shift schedule in a pulp and paper mill. Six workers were selected from the paper manufacturing section (group 1) and six workers from the chemical products section (group 2). Average heart rate (in beats per min) monitored during duty time was 84.3 in group 1 and 87.4 in group 2. Average heart rate during work was not significantly higher than that during rest in both groups 1 (work 85.8, rest 75.3) and 2 (work 87.9, rest 83.1). There was no significant difference in the total number of steps walked. A non-significant decrease in systolic blood pressure value was found in group 1 compared with that in group 2. Although future studies will be needed to explain the relation between different work styles and their effects on the health of shift workers, our results suggest no significant difference in heart rates among workers engaged in different kinds of work on the same shift work schedule.     

Mechanical detachment of the anterior hyaloid membrane from the posterior lens capsule1

Objective

To investigate the incidence of spontaneous detachment of the anterior hyaloid membrane from the posterior lens capsule and to explore the possibility of surgical separation of the anterior hyaloid membrane.

Comparative study of short-term anxiolytic potency of alprazolam and tandospirone in psychiatric outpatients with anxiety disorders

Anxiolytic potency of 1 week of treatment with alprazolam or tandospirone in psychiatric outpatients with anxiety disorders was evaluated by changes in the scores on the Hamilton Anxiety Scale and the State and Trait Anxiety Inventory and in the saliva level of free-3-methoxy-4-hydroxyphenylglycol (free-MHPG). Saliva level of free-MHPG was significantly reduced by 1 week of treatment with alprazolam but not with tandospirone. Reductions in the HAS score after 1 week of drug treatment were greater in patients treated with alprazolam than in those treated with tandospirone. These results indicate that the short-term anxiolytic potency of alprazolam is greater than that of tandospirone and that the saliva level of MHPG would be a useful marker for the evaluation of the therapeutic potency of anxiolytic agents. Copyright 2001 John Wiley & Sons, Ltd.