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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.

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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.

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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.

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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

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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.

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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.

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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

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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.

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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)

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