Magnetic stimulation of the quadriceps: analysis of 2 stimulators used for diagnostic and therapeutic applications

Compromised muscle function can be evaluated in respiratory disease patients by supramaximal magnetic stimulation (isometric twitch) of the quadriceps, a technique that is reproducible and objective. We validated the technique, comparing a device used in our laboratory with another reference electromagnet. We also assessed whether the technique could potentially be used to train the muscle by repetitive stimulation. The Medtronic Magpro (MED) device with a circular coil and the Magstim 200 device (MAG) with a figure-of-eight coil (reference device) were used to stimulate the femoral nerve of 6 volunteers at different percentages of maximal output. MED stimulation was also applied on the quadriceps muscle. We measured voluntary contractions, comparing measurements from the 2 devices and on different days. The stimulation achieved with MED was lower than with MAG, showed greater day-to-day variability, and was not clearly supramaximal. MED quadriceps stimulation was 80.7% of MAG stimulation. In conclusion, supramaximal stimulation of the quadriceps cannot be guaranteed with MED and the circular coil. However, this device generates sufficient contraction when applied to the muscle to be used for repetitive stimulation.     

Cartilage tissue enhances proteoglycan retention by nucleus pulposus cells in vitro

Objective

To investigate the effect of cartilage on nucleus pulposus (NP) tissue in an in vitro model.

Methods

Cells were isolated from bovine NP or articular cartilage and allowed to form tissue in vitro. The NP tissue was grown either alone or in the presence of cartilage tissue (coculture) for up to 4 weeks and examined for histologic appearance, gene expression, and biochemical composition. For selected experiments, NP tissue was grown in coculture with fragments of cartilage end‐plate.

Results

Coculture of in vitro–formed NP tissue with cartilage end‐plate tissue resulted in a significant increase in proteoglycan content in the NP tissue by 2 weeks, compared with NP tissue grown alone. Substituting in vitro–formed cartilage tissue for cartilage end‐plate also had a positive effect on the NP tissue, suggesting that it was an appropriate substitute for cartilage end‐plate. Coculture of NP with in vitro–formed cartilage for 2 weeks increased aggrecan and collagen gene expression compared with that in NP tissue grown alone, and also reduced expression of matrix metalloproteinase 3 (MMP‐3), MMP‐13, and ADAMTS‐5. NP cells from older and younger animals responded similarly to in vitro–formed cartilage. Expression of genes for tumor necrosis factor α (TNFα) and TACE in NP cells was higher when grown in the absence of cartilage. This corresponded with increased TNFα protein levels in the absence of cartilage.

Conclusion

The data suggest that chondrocytes may secrete a factor(s) that positively enhances tissue growth, perhaps by inhibiting TNFα production. This could be a potential mechanism explaining how loss of the cartilage end‐plate may contribute to the development of NP degenerative changes.

     

No depletion of Wolbachia from Onchocerca volvulus after a short course of rifampin and/or azithromycin

Endosymbionic Wolbachia bacteria inside adult Onchocerca volvulus worms (causing river blindness) are necessary for female worm fertility. We evaluated whether rifampin and/or azithromycin used in a five-day course could kill Wolbachia. In an open-label trial in Guatemala, 73 patients with 134 palpable onchocercal nodules were randomized into four treatment groups: rifampin, azithromycin, a combination of the two drugs, and controls (multivitamins). After five days of antibiotic treatment, all participants received a single dose of ivermectin on day 6. Nine months after treatment, the nodules were removed and the worms were examined. Skin snips to determine microfilariae were obtained at baseline and nine months. There were no significant differences between any of the treatment groups in the condition of the worms in the nodules, the presence of Wolbachia surface protein, or the number of microfilariae in skin. Short courses with these antibiotics will not clear Wolbachia from O. volvulus.     

Sleep improves sequential motor learning and performance in patients with prefrontal lobe lesions

OBJECTIVES: Motor skill learning involves both practice and a latent, sleep-dependent process of consolidation that develops after training ("off-line" learning). Sleep consolidation is linked to reduced brain activation in prefrontal areas, along with strong involvement of parietal regions. The objective in this study was to investigate the influence of sleep on the consolidation process of a motor task in patients with prefrontal damage. PATIENTS AND METHODS: For that purpose 14 patients with acquired focal prefrontal lesions, 15 age-matched healthy controls, and five patients with parietal lesions were evaluated on a serial reaction time task, SRTT, before and after a night of monitored sleep. Verbal and working memory was also tested. We anticipated that patients with prefrontal lesions, who are impaired in the acquisition of motor tasks, would benefit greater from sleep than the other two groups, since consolidation does not depend on prefrontal regions. RESULTS: Prefrontal patients showed an erratic learning curve at night, with great inter- and intrasubject variability that normalized after sleep. They also showed higher overnight learning of the motor skill and improvement on speed performance on the SRTT. No differences in the other memory tests were found between sessions. CONCLUSION: Prefrontal-injured patients benefit from night sleep in terms of motor task learning and performance, likely related to an advantageous off-line learning. Sleep could play a role in motor rehabilitation programs in prefrontal patients.     

The effect of benztropine on haloperidol-induced dystonia, clinical efficacy and pharmacokinetics: a prospective, double-blind trial

Twenty-nine inpatients with major psychotic disorders were treated for 14 days with a clinician-determined dose of haloperidol and with either benztropine or placebo given by double-blind random assignment on days 1 through 7. No differences were noted in haloperidol mean dose, haloperidol blood levels, or BPRS scores during the first seven days between benztropine (N = 14) and placebo (N = 15) groups. Benztropine-treated patients demonstrated increased dry mouth and diminished sweat and a non-significantly lower rate of dystonia compared to placebo (14% vs. 33%). Dystonic patients were significantly younger than nondystonic patients, but did not differ in haloperidol mean dose or plasma concentration. The effect of benztropine on the incidence of dystonia was consistent with other studies, which, when analyzed together, demonstrate the efficacy of anticholinergic prophylaxis. The relatively low incidence of anticholinergic side effects, coupled with the lack of effect on haloperidol blood levels or antipsychotic efficacy, suggest that moderate doses of benztropine in conjunction with haloperidol are a rational approach for the treatment of acute psychosis in young patients.     

Ingesta de flúor a través del consumo de agua de abastecimiento público en la cohorte INMA-Gipuzkoa

Objective

To estimate fluoride intake through consumption of water from the municipal network in pregnant women and their children from the INMA-Gipuzkoa cohort and to compare these intakes with recommended levels. In Euskadi (Spain), fluoridation of drinking water is compulsory in water supplies for more than 30,000 inhabitants.