Possible activation of murine T lymphocyte through CD98 is independent of interleukin 2/interleukin 2 receptor system

CD98 is a widely expressed cell surface heterodimeric protein of 125 kDa. Its expression is upregulated during lymphocyte activation induced by mitogen, superantigen, conventional antigen, and a combination of phorbol myristate acetate (PMA) and ionomycin. However, the role of CD98 in the immune system is not so well understood. The role of CD98 in murine T lymphocyte proliferation was investigated, especially in correlation with the interleukin 2 (IL-2)/interleukin 2 receptor (IL-2R) system. Monoclonal antibody (mAb) directed against murine CD98 heavy chain (mCD98HC) suppressed the proliferation of lymphocytes stimulated with concanavalin A (Con A). Anti-mCD98HC mAb did not suppress the expression of IL-2Ralpha. Anti-IL-2Ralpha mAb, which suppressed DNA synthesis, did not inhibit the expression of CD98HC. Murine IL-2 (recombinant), which induced considerable DNA synthesis by lymphocytes stimulated with a sub-optimal dose of Con A, did not induce CD98HC expression in lymphocytes. In addition, anti-mCD98HC mAb did not inhibit the production of IL-2 by lymphocyte stimulated with Con A. Taken together with these findings, it was speculated that the CD98 system is independent of the IL-2/IL-2R system in murine T lymphocyte activation.     

Enhanced stretch reflex excitability of the soleus muscle in persons with incomplete rather than complete chronic spinal cord injury

OBJECTIVE: To compare excitabilities of spinal stretch reflex among clinically complete spinal cord injury (SCI), incomplete SCI, elderly healthy, and young healthy subjects. DESIGN: Case comparison. SETTING: Research laboratory. PARTICIPANTS: Volunteer sample of 12 complete SCI, 10 incomplete SCI, 10 elderly, and 11 young subjects. INTERVENTION: Mechanically induced stretch reflex, H-reflex, and M response in electromyographic activity of the soleus muscle were recorded in all subjects. MAIN OUTCOME MEASURES: Absolute peak-to-peak stretch reflex amplitude and maximum H-reflex (Hmax), and those values relative to the maximum M response (Mmax) amplitude (relative peak-to-peak stretch reflex amplitude) and H/M ratio. RESULTS: Both the absolute and relative peak-to-peak stretch reflex amplitudes showed the greatest values in incomplete SCI among the 4 groups. Although absolute and relative peak-to-peak stretch reflex amplitudes of the incomplete SCI group were greater than those of the complete SCI group, the H/M ratios of both groups were comparable, and were greater than those of the younger and elderly groups. CONCLUSIONS: The results suggest that the greater absolute and relative peak-to-peak stretch reflex amplitudes of incomplete SCI were mostly due to the greater maximum motor potential (Mmax), while the elevated spinal motoneuronal excitability shown by the increased H/M ratio was maintained in the chronic stage after both complete and incomplete SCIs.     

Development of speech and hearing of two children with Pelizaeus-Merzbacher disease presenting only waves I and II of the auditory brainstem response

Pelizaeus-Merzbacher disease (PMD) is a white matter dystrophy of the brain. Most children with PMD require comprehensive nursing care. Their speech and language abilities are poor or absent. Therefore, evaluating hearing ability is difficult in children with PMD. We have followed up two patients with PMD since early childhood. Patient 1 is an 11-year-old boy, and patient 2 is a 15-year-old adolescent boy in whom horizontal nystagmus was recognized after birth. Magnetic resonance imaging showed diffuse dysmyelination of the cerebral white matter. Auditory brainstem response recordings showed only waves I and II and the absence of all subsequent components. However, conditioned orientation reflex audiometry showed a threshold of 20-30 dB. Both patients can converse orally and have auditory perception and speech abilities better than those of most patients with PMD in the literature. We report on the development of their hearing and speech abilities.     

Catheter‐related Infections via Temporary Vascular Access Catheters: A Randomized Prospective Study

Temporary vascular access catheters (VACs) are important devices used in acute blood purification therapies. The aim of this study was to determine whether a catheterization duration of 2 weeks increased the risk of nosocomial complications when compared with a 1‐week duration. Fifty‐six patients with 90 double lumen VACs were randomly chosen, and received either 1‐ or 2‐week catheterizations from operators experienced in the placement of such catheters at three sites such as the internal jugular, subclavian, or femoral vein. The characteristics of the VACs, including the sites, procedures, and lengths, were similar in both groups. No significant difference in the rate of catheter colonization was observed between the groups (14.6% vs 26.2%, P = 0.1371). No significant difference in the rate of catheter‐related bloodstream infections was observed between the groups (2.1% vs 4.8%, P = 0.5967). Two‐week indwelling did not increase the risk of infection compared with 1‐week indwelling at any of the sites in critically ill patients.     

Changes in corticospinal excitability during observation of walking in humans

To address whether the passive observation of walking would induce an increase in motor cortical excitability, we examined the responses of motor-evoked potential elicited by transcranial magnetic stimulation in the tibialis anterior and soleus muscles as the participants observed naturally performed walking. Motor-evoked potentials in these muscles were significantly increased during the observation of walking throughout the entire step-cycle periods, but not during specific step periods. These findings indicate that cortical excitability can be increased not only during the observation of voluntary hand/arm movements, but also during the observation of automatic movements such as walking. It is also suggested that the present results may reflect the increased cortical excitability during the entire walking cycle.     

Vibrio vulnificus pollution of imported frozen Black Tiger shrimps in Japan

The Ariake Sea area of Japan is endemic for Vibrio vulnificus infection. V vulnificus was isolated from slime from tidal flats, seawater, and fish Sea year-round as we reported previously. To identify new routes and factors of V vulnificus infection, we studied V. vulnificus pollution of imported frozen Black Tiger shrimps purchased from a fish market in Kurume, Fukuoka, Japan. V. vulnificus was isolated from 9 of 100 tails (9%) of Philippines products, 3 of 100 tails (3%) of Indonesia products, and 0 out of 100 tails (0%) of Madagascar products. Cytotoxin-hemolysin genes were identified in 7 V. vulnificus strains isolated from patients with V vulnificus septicemia, 9 strains from Philippine products, and 3 strains from Indonesian products. These results suggest that imported frozen Black Tiger shrimps are a new sources of V. vulnificus infection.     

A magnetoencephalographic study of Japanese vowel processing

Magnetic brain responses were recorded to clarify the cortical representation of vowel processing in Japanese. We investigated the peak latencies and equivalent current dipoles of the auditory N1m responses to the Japanese vowels [a], [i], [o], and [u]. In intraindividual analyses for a single participant, well-replicated results for the dipole parameters supported the existence of phoneme-specific cortical maps for vowels. In the interindividual analyses for the eight participants, [a] and [i] elicited significantly earlier N1m responses than [u], and the dipole for [i] was more posteriorly oriented than [a] in the left hemisphere. The results of the current study suggest left hemispheric predominance in vowel processing and that factors associated with a different language system may modify the cortical map.     

Better time-intensity trade revealed by bilateral giant magnetostrictive bone conduction

Sound lateralization tests were performed to compare the magnet coil bone-conduction headphone with the giant magnetostrictive bone-conduction headphone using 18 healthy participants. Although, no significant difference between these bone-conduction headphones was obtained for the interaural time difference and interaural intensity difference, a significant difference was obtained for the time-intensity trade. This revealed that the difference between the headphones is apparent in the integration of the heterogeneous sensations of the time and intensity difference at the cognitive level, but no difference is apparent between the homogeneous sensations of the discrimination of interaural time difference or interaural intensity difference at the sensory level. It was concluded that the difference at the cognitive level indicates the better performance of the giant magnetostrictive headphone.