Effects of repetitive transcranial magnetic stimulation on voice and speech in Parkinson's disease.

OBJECTIVE: To investigate the effects of repetitive transcranial magnetic stimulation (rTMS) on vocal function in Parkinson's disease (PD). MATERIAL AND METHODS: Two different sets of rTMS parameters were investigated on 30 patients with PD: active or sham 15 Hz rTMS of the left dorsolateral prefrontal cortex (LDLPFC) (110% of motor threshold (MT), 3000 pulses per session) and active 5 Hz rTMS of the primary motor cortex (M1)-mouth area (90% MT, 2250 pulses per session). A blind rater evaluated speech characteristics (acoustic and perceptual analysis of voice) and voice-related quality of life (V-RQOL). RESULTS: rTMS of LDLPFC resulted in mood amelioration and subjective improvement of the V-RQOL only (71.9% improvement, P < 0.001), but not in objective measures such as fundamental frequency (P = 0.86) and voice intensity (P = 0.99). On the other hand, rTMS of M1-mouth induced a significant improvement of the fundamental frequency (12.9% for men and 7.6% for women, P < 0.0001) and voice intensity (20.6%, P < 0.0001). CONCLUSIONS: Our findings provide initial evidence that rTMS of the primary motor cortex might yield a beneficial effect on vocal function in PD.

The utilization of thiocyanate as a nitrogen source by a heterotrophic bacterium: the degradative pathway involves formation of ammonia and tetrathionate.

A Gram-negative soil bacterium (isolate 26B) has been shown to utilize up to 100 mM thiocyanate as a source of nitrogen when supplied with glucose as the source of carbon and energy. During growth of isolate 26B with thiocyanate as the source of nitrogen, no ammonia, nitrate, nitrite, cyanide, cyanate, sulfate, sulfite, sulfide or carbonyl sulfide was detected in the growth medium. Growth of the bacterium on 14C-labelled thiocyanate (1.6 microCi) and glucose, yielded 14C-labelled carbon dioxide (0.9 microCi). The addition of 2.9 mM thiocyanate to a bacterial suspension in phosphate buffer (50 mM, pH 7.4) resulted in the utilization of 2.1 mM thiocyanate and the production of 2.0 mM ammonia. This activity was inducible and only occurred after growth of the bacterium with thiocyanate as the source of nitrogen. Tetrathionate (0.7 mM) was detected in the medium after the utilization of thiocyanate (2.4 mM) by a suspension of the bacterium in phosphate buffer, and thiosulfate (1.0 mM) was detected as an intermediate. The addition of sulfide or thiosulfate to the bacterial suspension also resulted in the formation of tetrathionate. The utilization of both of these compounds appeared to be constitutive. A pathway for thiocyanate utilization by isolate 26B is proposed which involves the hydrolysis of thiocyanate to produce cyanate and sulfide. The cyanate then undergoes further hydrolysis to form ammonia and carbon dioxide. The sulfide is ultimately oxidized to tetrathionate via a pathway which includes thiosulfate.