Trans-spinal magnetic stimulation induces co-activation of the diaphragm and biceps in healthy subjects

The present study was designed to examine the effect of trans-spinal magnetic stimulation on bilateral respiratory and forelimb muscles in healthy subjects. Two wings of a figure-of-eight magnetic coil were placed on the dorsal vertebrae, from the fifth cervical to the second thoracic dorsal vertebra with a center at the seventh cervical vertebra. The surface electromyograms of bilateral diaphragm and biceps were recorded in response to trans-spinal magnetic stimulation with 20%-100% maximum output of the stimulatory device in male (n = 12) and female participants (n = 8). Trans-spinal magnetic stimulation can induce a co-activation of bilateral diaphragm and biceps when the stimulation intensity is above 60%. The onset latency was comparable between the left and right sides of the muscles, suggesting bilateral muscles could be simultaneously activated by trans-spinal magnetic stimulation. In addition, the intensity-response curve of the biceps was shifted upward compared with that of the diaphragm in males, indicating that the responsiveness of the biceps was greater than that of the diaphragm. This study demonstrated the feasibility of utilizing trans-spinal magnetic stimulation to co-activate the bilateral diaphragm and biceps. We proposed that this stimulatory configuration can be an efficient approach to activate both respiratory and forelimb muscles.

Near-field scanner for moving molecules

We have fabricated using electron beam nanolithography a fixed slit near-field optical scanning device which uses near-field fluorimetry to achieve 200 nm spatial resolution of objects moving over the slits. We explore the basic physics of operating narrow slits in the waveguide cutoff mode and present data from the passage of extended double-stranded DNA molecules passing over the slits as a first example of how this device can be used to do ultrahigh spatial resolution mapping of long polymers.

Normative data of quantitative thermal and vibratory thresholds in normal subjects in Taiwan: gender and age effect

BACKGROUND

Quantitative sensory testing has gained popularity as a tool in the diagnosis of peripheral neuropathies. This study aims to establish normative data of quantitative thermal and vibratory thresholds in normal subjects in Taiwan. In addition, we also examined the effect of age and gender differences on these thresholds.

METHODS

The study included 100 healthy subjects (50 males and 50 females) who were admitted for regular physical examination. The quantitative testing of thermal, cold and vibratory sensations were performed having recourse to a Thermotest instrument applied on the right hand and foot of these subjects. Measurements included perception thresholds of warm (WT), cold (CT), heat pain, cold pain and vibration as well as a visual analog pain scale.

RESULTS

Age was comparable between the sexes, but the male subjects were taller than the female subjects. A higher WT and CT in the hand, but not in the foot, were found in the male subjects in comparison with the female subjects. Heat pain threshold and cold pain threshold of both sites did not significantly differ between genders. Moreover, the groups did not differ in vibration threshold and visual analog pain scale. Young subjects (age < 30 years) showed a higher CT in the foot than the older subjects (age > 50 years). None of the above parameters were different between these two age groups. Overall, the age or height bore no significant relation to the difference between WT and CT (DDWT-CT).

CONCLUSIONS

The female subjects were found to be more sensitive to warm and cold stimulation in the hand than their counterparts. These results have provided valuable normative data on sensory perceptive thresholds in Taiwanese, which are useful as a tool in the diagnosis of peripheral neuropathy.

Auditory effect of kanamycin given to newborn guinea pigs whose mothers received kanamycin during pregnancy

Clinical and experimental data indicate that aminoglycoside ototoxicity occurs more frequently in individuals previously exposed to ototoxic drugs. This study investigated the auditory effect of repetitive administration of kanamycin on newborn guinea pigs that had previously been exposed, in utero, to kanamycin administered to their mothers. Sixteen pregnant guinea pigs in the late stages of gestation were divided into two groups, one receiving kanamycin 500 mg/kg per day intramuscularly for 8 days, and the other acting as a control. After birth, the mothers and their newborns in both groups were examined for auditory brain stem response (ABR) and then treated with kanamycin 500mg/kg per day for 4 days. The results from the second examination demonstrated that the group receiving prior treatment with kanamycin, despite their good ABR responses during the first measurement, showed significantly elevated auditory thresholds compared to the control group. Therefore, any ototoxic drugs should be used with extreme caution in newborns having had prior exposure to the drugs in utero, even if they have a "normal" auditory response after birth.

Early-stage development of auditory center: an experimental study of auditory evoked electrophysiologic recordings from fetal and newborn guinea pigs

Five guinea pig fetuses at 8 weeks' gestation (term is 9 weeks) were tested for auditory brain stem response (ABR) generated by earphones placed outside the maternal abdomen. The results obtained from these fetuses were compared with the ABRs in 10 term newborn guinea pigs on the 1st and 20th day after delivery. The ABRs indicated a decreasing peak latency over wave III with increasing age. The interpeak latency to wave III-V decreased markedly, with very little change in wave I-III. The results suggested rapid maturation of the upper brain stem and midbrain during late gestation and in newborns. They also exhibited an increasing peak latency of ABRs from both fetuses and newborns with decreasing stimulus intensity.

A proposed new paracentesis electrode for the measurement of foetal auditory brain stem response: a preliminary report

A proposed new electrode for measurement of foetal auditory brain stem response (ABR) is presented, the structure of which resembles a syringe needle. It can be placed subdermally in the head of the guinea pig foetus through the wall of the maternal abdomen. In the anterior end of the electrode a special device similar to a hook is situated. The device may be controlled from outside the maternal abdomen. In comparison with the placement of electrodes through the surgical incision, its placement is simple and injury to tissue is relatively small. It is not only firmly fixed in the subcutaneous tissue of the foetus to satisfy the need for the measurement of foetal ABR, but is easily removed from the foetus. To our knowledge no other similar electrode has been reported.