(Chitosan-g-glycidyl methacrylate)-xanthan hydrogel implant in Wistar rats for spinal cord regeneration.

This work reports the results of in vivo assays of an implant composed of the hydrogel Chitosan-g-Glycidyl Methacrylate-Xanthan [(CTS-g-GMA)-X] in Wistar rats. Degradation kinetics of hydrogels was assessed by lysozyme assays. Wistar rats were subjected to laminectomy by cutting the spinal cord with a scalpel. After the surgical procedure, hydrogels were implanted in the injured zone (level T8). Somatosensory evoked potentials (SEPs) obtained by electric stimulation onto periphery nerves were registered in the corresponding central nervous system (CNS) areas. Rats implanted with the biomaterials showed a successful recovery compared with the non-implanted rats after 30days. Lysozyme, derived from egg whites, was used for in vitro assays. This study serves as the basis for testing the biodegradability of the hydrogels (CTS-g-GMA)-X that is promoted by enzymatic hydrolysis. Hydrogels' hydrolysis was studied via lysozyme kinetics at two pH values, 5 and 7, under mechanical agitation at 37°C. Results show that our materials' hydrolysis is slower than pure CTS possibly due to the steric hindrance imposed by the GMA grafting of functionalization. This hydrolysis helps degrade the biomaterial and at the same time it provides support for spinal cord recovery. Combination of these results may prove useful in the use of these hydrogels as scaffolds for cells proliferation and their application as implants in living organisms.

Development and application of reflexodent in the quantitative functional evaluation of chewing control in patients with temporomandibular joint dysfunction and a control group.

BACKGROUND: There has been controversy with respect to the diagnostic value of the inhibitory masseteric reflex in temporomandibular joint dysfunction (TMJD) because the whole reflex response was not considered. The purpose of this study was to characterize the reflex changes that occur in patients with different levels of TMJD and in a control group. METHODS: Eighty-nine patients (ages 31.14 +/- 12.74 years) divided into three groups were studied and compared. The control group was without TMJD (n = 30), with moderate symptoms (n = 30), and with severe symptoms (n = 29). Using an instrument and a software program developed by our group (Reflexodent), the masseteric inhibitory reflex was studied. The electromyography record (EMG) was captured with surface electrodes and the inhibitory reflex was produced by tapping the chin. The EMG signal was processed, filtered, and averaged with the Reflexodent. Twenty series of records were applied to each patient. The faulty inhibitory area, the area's relation (potentiation/inhibition) regarding the values of healthy subjects previously characterized, and the bilateral symmetry were measured. RESULTS: Discriminate analysis showed a statistically significant correlation between clinical groups and electromyographic findings. Statistical function explained 91.8% of the discrimination among groups (canonical correlation = 0.918, chi(2) = 164.435, p <0.001). CONCLUSIONS: The study of whole inhibitory masseteric reflex and the Reflexodent technique are useful as a diagnostic tool to evaluate TMJ illness in the dental clinic.

Improved automatized recording of masticatory reflexes through analysis of effort trajectory during biofeedback.

Tap and sound evoked inhibitory motor reflexes within masseteric EMG were studied by means of a new technique that uses real time analysis of the trajectory followed during voluntary occlusal effort, controlled through visual biofeedback, in order to stimulate on exactly the same activity background. This technique uses a two computers system, doing parallel processing to support data acquisition, video indication, calculus of the pursued trajectory and evaluation of it. Stimuli were automatically delivered when the effort's trajectory fulfilled a set of conditions. Denomination of reflexigram (RFXG) is proposed to the cumulative, rectified and filtered EMG's series so recorded. Normal morphologies of RFXG were established on a 90 normal patients group. Clear clinical correlations were also found within two groups: 30 bruxists and 50 with temporomandibular joint dysfunction.

Electromyographic changes resulting from orthodontic correction of Class III malocclusion.

This study measured the electromyographic (EMG) amplitudes of the interference pattern (IP) and the integrated EMG (IEMG) of the masseter and temporal muscles in 10 children with Class III malocclusion before, during, and after treatment with a myofunctional appliance (the monobloc), and compared the EMG values with those obtained from 10 children with Class I occlusion. The results showed that before treatment the mean amplitude values of IP were significantly higher in the Class III than in the Class I group. The mean amplitude values for IP activity in both muscles decreased during and after treatment; however, mean values of the IEMG activity did not show significant change for either muscle. These results are attributed to changes in the length of the muscle fibres as well as to neural modifications. This study demonstrates a non-invasive method that can be used to study the functional effects of orthodontic treatment.

[Electrophysiological evaluation of occlusal splint treatment of patients with temporomandibular joint dysfunction]. / Valoración electrofisiológica de tratamiento con férula oclusal en pacientes con disfunción de la articulación temporomandibular.

Blink reflex time records were obtained from patients with temporomandibular joint disfunction (TMJD), before and after treatment with occlusal splint, since blink reflex time helps to study the trigeminal-facial functional relationship. Results suggest that the impaired sensory-motor function in the trigeminal-facial complex of TMJD patients, may return to normal latency values following such treatment.

Valoración electrofisiológica de tratamiento con férula oclusal en pacientes con disfunción de la articulación temporomandibular / Electrophysiologic evaluation of treatment with occlusal splint in patients with temporomandibular joint dysfunction

En el presente trabajo se obtuvieron los registros de potencial provocado por la técnica de reflejo de parpadeo en pacientes con disfunción de la articulación temporomandibular (DATM) previo y posterior al tratamiento con férula oclusal. Dicha técnica explora el complejo trigémino facial (sensorial y motor respectivamente), el cual participa en la modulación de la actividad motora de los músculos que mueven la articulación temporomandibular. Los resultados muestran una disminución de las latencias de los componentes del potencial posterior al tratamiento, las cuales se encontraban aumentadas antes del mismo. También indica una participación de estructuras a nivel central en la DATM, así como una posible utilidad de la técnica de estudio utilizada en la valoración de la misma

Effect of occlusal splint therapy on blink reflex time in TMJ dysfunction patients.

This study compares the changes that occur in latency before and after use of splint therapy in patients with TMJ dysfunction. The sensory fibers of the upper branch of the trigeminal nerve were stimulated and the time required for the sensory and motor responses to occur were measured. A reduction in latency occurred in the late component. Also a reduction of the delay occurred between ipsi and contralateral late responses. This finding can be attributed to the lateral reticular formation in the blink reflex arc. This study demonstrates a method for evaluating TMJ dysfunction and a way to monitor clinical response.

[Electromyographic activity (EMG) of masseter and temporal muscles in edentulous patients before and after complete dentures]. / Actividad electromiográfica (EMG) de los músculos masetero y temporal en pacientes edéntulos antes y después del uso de prótesis completa.

Electromyographic records from the temporal and masseter muscles of 19 edentulous patients were made, before and 30 days after wearing complete dentures. The purpose of this study was to determine the electromyographic changes: The amplitude of electromyographic records from de temporal muscles decreased, while those from the masseter muscles increased. These results suggest that the use of complete denture provokes electromyographic changes by increasing the occlusal vertical dimension and, thus, periodical electromyographic records from temporal and masseter muscles could be useful for determining the time for complete denture change.

[Objective evaluation of the masseter and temporal muscles in treatment of Class III occlusion with the monoblock. Initial results]. / Valoración objetiva de los músculos masetero y temporal en el tratamiento de la oclusión Clase III con monoblock. Resultados iniciales.

On ten patients, aged four to 12, with class III functional occlusion, simultaneous electromyographic activity in the masseter and temporal muscles, under conditions of centric occlusion and maximal voluntary contraction, was recorded for 30 seconds. Recording of electromyographic activity was repeated 15 days after initiating treatment with a monoblock device. Results show a lowering of the electrical activity of the aforementioned muscles and, indirectly, of their mechanical capacity during contraction, which may be due to a distention of seid muscles by action of the monoblock. We hereby postulate that, in the muscles under study, a larger previous length results in a lower force of contraction, and such conditions pose a risk of muscular insufficiency.

Sensibilidad del canal anal de sujetos normales y pacientes tratados quirurgicamente de malformacion anorrectal: estudio mediante la tecnica de potenciales provocados. / Sensitivity of the anal canal in normal subjects and in patients surgically treated of anorectal malformation, study with evocked potentials technic

En condiciones fisioloficas la actividad motora que se lleva a cabo en el acto de defecacion depende de la informacion sensorial proveniente de la region del canal anal; sin embargo, en los estudios sobre el problema de incontinencia anal en pacientes con malformacion anorrectal tratados quirurgicamente, muy poco se ha tomado en cuenta el factor percepcion. Con el objetivo de determinar si existen diferencias en la actividad electrica de la via sensorial que se origina en los receptores del canal anal de sujetos normales y aquella de pacientes tratados quirurgicamente para correccion de malformacion anorrectal se estudiaron mediante la tecnica de potenciales, provocados 22 ninos aparentemente sanos y 11 pacientes. Nuestros resultados demuestran una actividad electrica de la via sensorial de los pacientes de menor intensidad y de conduccion ma lenta que la de los sujetos normales; inclusive en algunos pacientes no aparecio actividad Se sugiere que la alteracion sensorial podria ser en parte responsable de la incontiencia anal que pueda presentarse posteriormente en estos pacientes

[Effect of naloxone on somatosensory evoked potentials in congenital insensitivity to pain]. / Efecto de naloxona sobre los potenciales evocados somatosensoriales en la insensibilidad congénita al dolor.

The somatosensory evoked potentials were recorded (SEP) in a child 11 years old with congenital insensitivity to pain. The records were made before and after naloxone administration (160 mg i.m.) and they were compared with the SEPs from normal children. The place where records were taken was the somatosensory area of the scalp and the site of the stimulation was the contralateral medial nerve of the wrist. The results show that naloxone provokes higher waves of the patient's SEP that before administration of naloxone. On the other hand lower SEPs were observed in the patient with congenital insensitivity to pain than in those from normal children. The results suggest that congenital insensitivity to pain could be related to abnormal activities of morphine-like substances of endogenous production.

Efecto de naloxona sobre los potenciales evocados somatosensoriales en la insensibilidad congenita al dolor. / Effect of naxolone on the somatosensory evoked potentials in congenital insensibility to pain

Se hizo registro de los potenciales evocados somatosensoriales(PES) en un nino de 11 anos con insensibilidad congenita al dolor antes y despues de la administracion de naloxona (160 mg.i.m.) y se compararon con los PES de ninos aparentemente sanos.Los resultados parecen indicar que la naloxona produce un aumento en la amplitud de los componentes de los PES registrados en el area somatosensorial del cuero cabelludo, contralateral al sitio de estimulacion en el nervio mediano a nivel de la muneca, por otra parte, hay una clara disminucion en la amplitud de los componentes de los PES registrados en el paciente con insensibilidad congenita al dolor con respecto a los obtenidos en un nino normal.Los resultados apoyan la suposicion de que los pacientes con insensibilidad congenita al dolor existe un aumento en las sustancias de produccion endogena parecidas a la morfina (endorfinas)