Innate defensive behaviour and panic-like reactions evoked by rodents during aggressive encounters with Brazilian constrictor snakes in a complex labyrinth: behavioural validation of a new model to study affective and agonistic reactions in a prey versus predator paradigm.

Defensive behaviour has been extensively studied, and non-invasive methodologies may be interesting approaches to analyzing the limbic system function as a whole. Using experimental models of animals in the state of anxiety has been fundamental in the search for new anxiolytic and antipanic compounds. The aim of this present work is to examine a new model for the study of affective behaviour, using a complex labyrinth consisting of an arena and galleries forming a maze. Furthermore, it aims to compare the defensive behaviour of Wistar rats, Mongolian gerbils and golden hamsters in a complex labyrinth, as well as the defensive behaviour of Meriones unguiculatus in aggressive encounters with either Epicrates cenchria assisi or Boa constrictor amarali in this same model. Among species presently studied, the Mongolian gerbils showed better performance in the exploration of both arena and galleries of the labyrinth, also demonstrating less latency in finding exits of the galleries. This increases the possibility of survival, as well as optimizes the events of encounter with the predator. The duration of alertness and freezing increased during confrontation with living Epicrates, as well as the duration of exploratory behaviour in the labyrinth. There was an increase in the number of freezing and alertness behaviours, as well as in duration of alertness during confrontations involving E.c. assisi, compared with behavioural reactions elicited by jirds in presence of B.c. amarali. Interestingly, the aggressive behaviour of Mongolian gerbils was more prominent against B.c. amarali compared with the other Boidae snake. E.c. assisi elicited more offensive attacks and exhibited a greater time period of body movement than B.c. amarali, which spent more time in the arena and in defensive immobility than the E.c. assisi. Considering that jirds evoked more fear-like reaction in contact with E.c. assisi, a fixed E.c. assisi kept in a hermetically closed acrylic box was used as control. In these prey/predator encounter-based experiments, there was an increase in the number of alertness and freezing behaviours exhibited by gerbils, and a decrease in the number of crossing elicited by them, when comparing confrontations between the living E.c. assisi and the control. The experiments were performed at 7.0 p.m. In the labyrinth, the snakes showed in confrontation similar performance to that observed in nature (organizing hunting behaviour, offensive/defensive attack, constriction, prey inspection and feeding behaviour), which were essential to the validity of the experiments and gave behavioural validation within the complex labyrinth.

Traumatismos raquimedulares penetrantes em adolescentes / Traumatismos raquimedulares penetrantes en adolescentes / Penetrating spinal cord injuries in adolescents

OBJETIVO: analisar a conduta em uma série de adolescentes com traumatismos raquimedulares penetrantes (TRMp) e, confrontando com a literatura, estabelecer a melhor estratégia terapêutica para esses pacientes. MÉTODOS: avaliação retrospectiva de prontuários médicos de dez pacientes, nove do sexo masculino e um do feminino, com TRMp e menores de 18 anos, tratados à nível hospitalar. Analisou-se a anamnese, o exame neurológico e os exames de imagem. A conduta terapêutica variou entre cirurgia ou conservador. RESULTADOS: a média de idade foi de 16 anos (13 a 18 anos). A mediana de hospitalização inicial foi de 11 dias (4 a 180 dias). Quatro pacientes foram submetidos à laminectomia, um ao desbridamento da lesão e os demais a tratamento conservador. Só um paciente, foi submetido à laminectomia, que migrou para Frankel E. Nenhum paciente apresentou infecção da ferida ou instabilidade tardia da coluna vertebral. CONCLUSÃO: as lesões medulares secundárias desempenham pouca importância no resultado neurológico, o que leva à definição clínica do quadro na admissão hospitalar da maioria dos casos. Houve uma nítida predominância de TRMp em adolescentes do sexo masculino. Não ocorreu diferença significativa entre as condutas realizadas em relação ao resultado neurológico, à infecção e instabilidade. O tratamento deve ser individualizado, não negligenciando o tratamento clínico e considerando a cirurgia apenas em casos específicos.

OBJECTIVE: to analyze the management of a series of adolescents with penetrating spinal cord injuries (pSCI) and comparing to literature, provide the best therapeutic strategy to these patients. METHODS: retrospective evaluation of medical reports of ten consecutive cases of pSCI, nine from the male sex and one from the female. All the patients were under 18 years old. The clinical history, neurologic evaluation and the images exams were analyzed. The therapeutic management varied between surgery and conservative. RESULTS: the average age was 16 years old (form 13 to 18 years). The median time spent at the first hospitalization was 11 days (from 4 to 180 days). Four patients were submitted to laminectomy, one to wound debridement and five to conservative treatment. Only one patient submitted to laminectomy had neurological improvement. No patients presented in this series showed, in the follow-up, wound infection or spinal instability. CONCLUSION: secondary spinal cord injuries are less relevant to the neurological status, which means that the sequelae are established at hospital admission in most of the cases. There was a clear predominance of pSCI in male adolescents. There was no significant difference between the cases that were managed clinically or surgically, concerning the neurological outcome, infection and instability. The therapy must be individualized, the clinical management must not be neglected and surgery must be considered only in specific cases.

OBJETIVO: analizar la conducta en una serie de adolescentes con traumatismos raquimedulares penetrantes (TRMp) y confrontar con la literatura, además de establecer la mejor estrategia terapéutica para eses pacientes. MÉTODOS: evaluación retrospectiva de historias clínicas de diez pacientes, nueve masculinos y un femenino de TRMp menores de 18 años, tratados a nivel hospitalar. Se analizó la anamnesis, el examen neurológico y los exámenes de imagen. La conducta terapéutica varió entre cirugía o tratamiento conservador. RESULTADOS: el promedio de edad fue de 16 años (13 a 18 años). La media de hospitalización inicial fue de 11 días (4 a 180 días). Cuatro pacientes fueron sometidos al tratamiento conservador. Solo un paciente sometido a laminectomía migró para Frankel E. Ningún paciente presentó infección de la herida o inestabilidad tardía de la columna vertebral. CONCLUSIÓN: las lesiones medulares secundarias desempeñan poca importancia en el resultado neurológico, lo cual lleva a la definición clínica del cuadro en la admisión hospitalar de la mayoría de los casos. Hubo una nítida predominancia de TRMp en adolescentes del sexo masculino. No ocurrió diferencia significativa entre las conductas realizadas en relación al resultado neurológico, infección e inestabilidad. El tratamiento debe ser individualizado, sin negligencia en el tratamiento clínico y considerando la cirugía sólo para casos específicos.