ABSTRACT
Tympanic membrane perforations are due to common otologic problems. The current treatments to heal tympanic membrane perforation, such as myringoplasty, have some disadvantages, including the need for autologous grafting, which is rapidly absorbed by the organism before perforation recovery is complete. To improve the structural and functional tympanic membrane healing after surgery, we propose a new branch of artificial grafts. In this study, we report the development of artificial grafts using electrospun bioabsorbable polymers. Polymers such as poly (l-lactic acid) and poly (lactic-co-glycolic acid) acted as the scaffold for cell growth in a co-culture of fibroblasts and keratinocytes. This co-culture promoted the growth of an epithelial-equivalent tissue over the electrospun scaffold, which was used as an alternative graft in myringoplasty. The in vivo study was performed in Sprague Dawley rats. Ear endoscopy was performed 30days after surgery and showed that tympanic membrane perforations treated with artificial grafts healed naturally, completely and with the possibility of maintaining their actual functionality. In conclusion, our study described a new artificial graft created specifically to fulfill the requirements of perforated tympanic membrane healing processes, which are compatibility, proper durability and less intense side effects following myringoplasty.
Subject(s)
Bioartificial Organs , Myringoplasty , Regeneration , Tympanic Membrane/physiology , Tympanic Membrane/surgery , Animals , Cell Death , Child , Child, Preschool , Endoscopy , Humans , Immunohistochemistry , Infant , Keratins/metabolism , Ki-67 Antigen/metabolism , Male , Polymers/chemistry , Rats, Sprague-Dawley , Temperature , Tissue Engineering , Tissue Scaffolds/chemistry , WettabilityABSTRACT
Our study was carried out to examine the relationships of the sigmoid sinus, tympanic membrane and digastric ridge with the mastoid segment of the facial nerve. We studied 33 adult temporal bones. The distances among these structures were evaluated according specific landmarks that can be repeated in a simple manner. We found a good relation, in a proportional and lineal order, between these three structures and the facial nerve. This study indicated a correlation between the position of these three structures and the mastoid segment of the facial nerve through a simple morphometric method.
Subject(s)
Facial Nerve/anatomy & histology , Mastoid/anatomy & histology , Tympanic Membrane/anatomy & histology , Adult , HumansABSTRACT
In the present study, we investigated the effect of immediate post-training bilateral infusion of spermidine, a polyamine agonist, into the amygdala on inhibitory avoidance learning of rats. Bilateral microinjection of spermidine (0.02--20 nmol) caused an increase in test step-down latencies at high concentrations. Administration of arcaine (0.002--0.2 nmol), an antagonist of the NMDA receptor polyamine binding site, decreased test step-down latencies. On the other hand, co-administration of arcaine and spermidine completely reversed the spermidine-induced increase of test step-down latencies. These results provide evidence that polyamines may be involved in learning and memory modulation in the amygdala.
Subject(s)
Amygdala/drug effects , Avoidance Learning/drug effects , Spermidine/pharmacology , Animals , Behavior, Animal/drug effects , Biguanides/pharmacology , Dose-Response Relationship, Drug , Male , Motor Activity/drug effects , Rats , Rats, WistarABSTRACT
Polyamines are polycations present at high concentrations in the mammalian brain. We investigated the effect of an intrahippocampal infusion of spermidine, a polyamine agonist, immediately post-training on the inhibitory avoidance learning paradigm in rats. Bilateral intrahippocampal microinjection of spermidine (0.02-20 nmol) caused an increase in test step-down latencies at low concentrations. Administration of arcaine (0.002-0.2 nmol), an antagonist of the N-methyl-D-aspartate (NMDA) receptor polyamine binding site, did not modify the test step-down latencies. In contrast, co-administration of arcaine and spermidine completely reversed the facilitatory effect of spermidine on the test step-down latencies. These results provide evidence that polyamines may be involved in learning and memory modulation.
Subject(s)
Avoidance Learning/drug effects , Hippocampus/physiology , Spermidine/pharmacology , Animals , Biguanides/pharmacology , Injections , Male , Motor Activity/drug effects , Rats , Rats, Wistar , Spermidine/administration & dosageABSTRACT
Guanidino compounds play specific physiological and pathological roles in the central nervous system. We investigated the effect of an intrahippocampal infusion of GMP (a guanidino compound) administered immediately post-training on the inhibitory avoidance learning paradigm in rats. Bilateral intrahippocampal micro-injection of GMP (0-30 nmol) caused a dose-dependent increase in test step-down latencies which was completely reversed by intrahippocampal co-administration of muscimol or baclofen (GABA agonists) or preadministration (15 min pre-training, i.p.) of MK-801 (an NMDA antagonist). These results provide evidence for a participation of GABA and NMDA receptors in the GMP-induced increase in the test step-down latencies.
