Comparison between two surgical techniques for prenatal correction of meningomyelocele in sheep / Comparação entre duas técnicas cirúrgicas de correção intrauterina da mielomeningocele em fetos de ovelha

OBJECTIVE: To compare the classical neurosurgical technique with a new simplified technique for prenatal repair of a myelomeningocelelike defect in sheep. METHODS: A myelomeningocele-like defect (laminectomy and dural excision) was created in the lumbar region on day 90 of gestation in 9 pregnant sheep. Correction technique was randomized. In Group 1 the defect was corrected using the classic neurosurgical technique of three-layer suture (dura mater, muscle and skin closure) performed by a neurosurgeon. In Group 2, a fetal medicine specialist used a biosynthetic cellulose patch to protect the spinal cord and only the skin was sutured above it. Near term (day 132 of gestation) fetuses were sacrificed for pathological analysis. RESULTS: There were two miscarriages and one maternal death. In total, six cases were available for pathological analysis, three in each group. In Group 1, there were adherence of the spinal cord to the scar (meningo-neural adhesion) and spinal cord architecture loss with posterior funiculus destruction and no visualization of grey matter. In Group 2, we observed in all cases formation of a neo-dura mater, separating the nervous tissue from adjacent muscles, and preserving the posterior funiculus and grey matter. CONCLUSION: The new simplified technique was better than the classic neurosurgical technique. It preserved the nervous tissue and prevented the adherence of the spinal cord to the scar. This suggests the current technique used for the correction of spina bifida in humans may need to be reassessed.

OBJETIVO: Comparar a técnica neurocirúrgica clássica a uma nova técnica simplificada, para correção de mielomeningocele, em fetos de ovelhas. MÉTODOS: Em 9 fetos, foi criado um defeito semelhante à mielomeningocele (laminectomia e excisão de dura-máter) no 90º dia de gestação. O tipo de correção foi randomizado. No Grupo 1, o defeito foi corrigido usando a técnica neurocirúrgica clássica, com a sutura de três camadas (dura-máter, músculo e pele), realizada por um neurocirurgião. No Grupo 2, um especialista em Medicina Fetal utilizou a técnica simplificada, colocando um fragmento de celulose biossintética sobre a medula e suturando apenas da pele sobre a celulose. Próximo ao termo da gestação (132 dias), os fetos foram sacrificados para análise anatomopatológica. RESULTADOS: Ocorreram dois casos de aborto e uma morte materna, restando seis casos para avaliação - três em cada grupo. No Grupo 1, todos os casos mostraram aderência da medula à cicatriz (meningoadesão) e perda da arquitetura medular, com destruição do funículo posterior e perda da visualização da substância cinzenta. No Grupo 2, observou-se, em todos os casos, a formação de uma neodura-máter, separando o tecido nervoso do músculo adjacente, sendo que o funículo posterior e a substância cinzenta estavam preservados. CONCLUSÃO: A técnica simplificada foi superior à neurocirúrgica, com maior preservação da medula e evitando as aderências do tecido nervoso. Os presentes achados sugerem que a técnica utilizada atualmente na correção de mielomeningocele em fetos humanos deva ser reavaliada.

Comparison between two surgical techniques for prenatal correction of meningomyelocele in sheep.

OBJECTIVE: To compare the classical neurosurgical technique with a new simplified technique for prenatal repair of a myelomeningocele-like defect in sheep. METHODS: A myelomeningocele-like defect (laminectomy and dural excision) was created in the lumbar region on day 90 of gestation in 9 pregnant sheep. Correction technique was randomized. In Group 1 the defect was corrected using the classic neurosurgical technique of three-layer suture (dura mater, muscle and skin closure) performed by a neurosurgeon. In Group 2, a fetal medicine specialist used a biosynthetic cellulose patch to protect the spinal cord and only the skin was sutured above it. Near term (day 132 of gestation) fetuses were sacrificed for pathological analysis. RESULTS: There were two miscarriages and one maternal death. In total, six cases were available for pathological analysis, three in each group. In Group 1, there were adherence of the spinal cord to the scar (meningo-neural adhesion) and spinal cord architecture loss with posterior funiculus destruction and no visualization of grey matter. In Group 2, we observed in all cases formation of a neo-dura mater, separating the nervous tissue from adjacent muscles, and preserving the posterior funiculus and grey matter. CONCLUSION: The new simplified technique was better than the classic neurosurgical technique. It preserved the nervous tissue and prevented the adherence of the spinal cord to the scar. This suggests the current technique used for the correction of spina bifida in humans may need to be reassessed.

Simplified correction of a meningomyelocele-like defect in the ovine fetus.

PURPOSE: To develop a simplified technique for antenatal correction of a meningomyelocele -like defect in fetal sheep to allow direct skin closure. METHODS: A spinal defect was surgically created at 75 days of gestation in the fetuses of 36 pregnant sheep, 23 survived the surgery. At 102 days gestation, the defect was corrected in 14 cases (9 were left untreated). Skin surrounding the defect was dissected below the dermis to permit its edges to be approximated and sutured, without interposing any material to its edges. An interface material intended to protect the neural tissue from skin adhesion was used and the skin defect was completely closed over it. Pregnancy was allowed to continue up to 138 days gestation, the fetuses were submitted to macroscopic and microscopic analysis. RESULTS: The defect was successfully corrected in 90.9% in the experimental group, and spontaneous closure occurred in 22.3% in the control group (p < 0.05). The survival rate after the creation and correction of the defect was 63.4% and 78% respectively. CONCLUSION: This simplified technique was successful in the correction a meningomyelocele-like defect, in the fetal sheep.

Simplified correction of a meningomyelocele-like defect in the ovine fetus / Correção simplificada de um defeito semelhante à meningomielocele em fetos de ovelha

PURPOSE: To develop a simplified technique for antenatal correction of a meningomyelocele -like defect in fetal sheep to allow direct skin closure. METHODS: A spinal defect was surgically created at 75 days of gestation in the fetuses of 36 pregnant sheep, 23 survived the surgery. At 102 days gestation, the defect was corrected in 14 cases (9 were left untreated). Skin surrounding the defect was dissected below the dermis to permit its edges to be approximated and sutured, without interposing any material to its edges. An interface material intended to protect the neural tissue from skin adhesion was used and the skin defect was completely closed over it. Pregnancy was allowed to continue up to 138 days gestation, the fetuses were submitted to macroscopic and microscopic analysis. RESULTS: The defect was successfully corrected in 90.9 percent in the experimental group, and spontaneous closure occurred in 22.3 percent in the control group (p < 0.05). The survival rate after the creation and correction of the defect was 63.4 percent and 78 percent respectively. CONCLUSION: This simplified technique was successful in the correction a meningomyelocele-like defect, in the fetal sheep.

OBJETIVO: Desenvolver uma técnica simplificada de correção pré-natal de defeito semelhante à mielomeningocele em fetos de ovelha permitindo um fechamento direto da pele. MÉTODOS: Um defeito espinhal foi cirurgicamente criado com 75 dias de gestação, em 36 fetos de ovelha, 23 sobreviveram à cirurgia. Após 102 dias de gestação, o defeito foi corrigido em 14 casos (9 não foram tratados). A pele em volta do defeito foi dissecada abaixo da derme para permitir a aproximação direta das bordas através de sutura, sem a interposição de nenhum material entre a pele. Um material de interface foi colocado entre o tecido neural exposto e a pele, com o objetivo de evitar a adesão da medula à pele, que foi completamente fechada sobre o defeito. A gravidez foi mantida até 138 dias, os fetos foram submetidos a análises macroscópicas e microscópicas. RESULTADOS: O defeito foi corrigido em 90.9 por cento no grupo experimental, e o fechamento espontâneo ocorreu em 22.3 por cento no grupo controle (p < 0.05). A taxa de sobrevivência após a criação do defeito e posteriormente a sua correção foi de 63,4 por cento e 78 por cento, respectivamente. CONCLUSÃO: Esta técnica simplificada teve sucesso na correção do defeito semelhante à mielomeningocele em feto de ovelha.

Biosynthetic cellulose induces the formation of a neoduramater following pre-natal correction of meningomyelocele in fetal sheep.

PURPOSE: The aim of this study was to compare the effectiveness of two dura-mater substitutes, namely human acellular dermal matrix (HADM) and biosynthetic cellulose (BC), in repairing, in utero, surgically-induced meningomyelocele (MMC) in fetal sheep. METHODS: A neural tube defect was created at 74-77 days gestation in 36 fetal sheep. They were divided into 3 groups, the control group that did not receive pre-natal corrective surgery, and the other two groups that received corrective surgery using HADM (Group A) or BC (Group B). Both materials were used as a dura-mater substitutes between the neural tissue and the sutured skin. Correction was performed at gestation day 100 and the fetuses were maintained in utero until term. Sheep were sacrificed on gestation day 140. The fetal spine was submitted to macro and microscopic analysis. At microscopy, adherence of the material to the skin and neural tissue was analyzed. RESULTS: In the initial phase (pilot), experimentally-induced MMC was performed on 11 fetuses and 4 survived (37%). In the second phase (study), 25 fetuses received surgery and 17 survived (68%). In the study group, 6 fetuses did not undergo repair (control group), 11 cases were submitted to corrective surgery (experimental group) and one fetal loss occurred. Of the surviving cases in the experimental group, 4 constituted Group A and 6 in Group B. Macroscopically, skin and underlying tissues where easily displaced from the BC in all cases it was used; in contrast, HADM adhered to these tissues. To compare the adherence, 4 cases from Group A and 4 in Group B were studied. We observed adherence, host cell migration and vessel proliferation into the HADM all sections from Group A and this aspect was not present in any cases in Group B (p < 0.05). In Group B, we also observed that a new fibroblast layer formed around the BC thus protecting the medulla and constituting a "neoduramater". CONCLUSION: The use of BC seems to be more adequate as a dura-mater substitute to cover the damaged neural tissue than HADM. It seems promising for use in the in utero correction of MMC because to does not adhere to neural tissue of superficial and deep layers ("tethered spinal cord"). Thus, BC minimizes the mechanical and chemical intrauterine damage to the spinal medulla.

Validation of the ovine fetus as an experimental model for the human myelomeningocele defect.

PURPOSE: To produce a myelomeningocele-like human defect in the ovine fetus and validate this experimental model in our population. METHODS: A prospective study on 12 pregnant sheep of a crossed Hampshire/Down breed where a spinal defect was surgically created between Day 75 and Day 77 after conception. The technique consisted of a hysterotomy with exposure of fetal hind limbs and tail up to the mid spine. Fetal skin, paravertebral muscles, and 4 posterior spinal arches were excised, exposing the spinal cord. Duramater was opened and the medulla was incised until the medullar canal. Animals were euthanized at 139 days of gestation for fetal evaluation. The central nervous system was submitted to post-mortem magnetic resonance imaging (MRI) and the spine was submitted to pathological examination. RESULTS: The defect was created in 13 fetuses and 5 survived. Mean gestational age at necropsy was 121.6 days (varying from 93 to 145 days). Macroscopically, the defect was present in 4 cases. Microscopy revealed a flattened medulla with disappearance of the medullar canal and disruption of normal medullar architecture with neuronal apoptosis and/or fusion of the piamater and duramater. The MRI showed herniation of the cerebellum into the cervical canal and syringomyelia. CONCLUSIONS: The surgically produced defect mimics the defect found in the human fetus, including the Arnold-Chiari malformation. Post-mortem MRI was used for the first time in our study and proved an excellent alternative for demonstrating the cerebellar herniation. We standardized the technique for creating the defect in our population.

Validation of the ovine fetus as an experimental model for the human myelomeningocele defect

PURPOSE: To produce a myelomeningocele-like human defect in the ovine fetus and validate this experimental model in our population. METHODS: A prospective study on 12 pregnant sheep of a crossed Hampshire/Down breed where a spinal defect was surgically created between Day 75 and Day 77 after conception. The technique consisted of a hysterotomy with exposure of fetal hind limbs and tail up to the mid spine. Fetal skin, paravertebral muscles, and 4 posterior spinal arches were excised, exposing the spinal cord. Duramater was opened and the medulla was incised until the medullar canal. Animals were euthanized at 139 days of gestation for fetal evaluation. The central nervous system was submitted to post-mortem magnetic resonance imaging (MRI) and the spine was submitted to pathological examination. RESULTS: The defect was created in 13 fetuses and 5 survived. Mean gestational age at necropsy was 121.6 days (varying from 93 to 145 days). Macroscopically, the defect was present in 4 cases. Microscopy revealed a flattened medulla with disappearance of the medullar canal and disruption of normal medullar architecture with neuronal apoptosis and/or fusion of the piamater and duramater. The MRI showed herniation of the cerebellum into the cervical canal and syringomyelia. CONCLUSIONS: The surgically produced defect mimics the defect found in the human fetus, including the Arnold-Chiari malformation. Post-mortem MRI was used for the first time in our study and proved an excellent alternative for demonstrating the cerebellar herniation. We standardized the technique for creating the defect in our population.

OBJETIVO: Produzir um defeito semelhante a meningomielocele humana em feto de ovinos, validando este modelo experimental, em nosso meio. MÉTODOS: Estudo prospectivo com 12 ovelhas de cruzamento das raças Hampshire e Down, onde um defeito na coluna foi criado cirurgicamente com 75 a 77 dias de gestação. A técnica consistiu em histerotomia com exposição das patas traseiras e cauda até a metade da coluna fetal. Foram retirados pele, musculatura paravertebral e 4 arcos vertebrais posteriores, expondo a medula. A dura foi aberta e uma incisão até o canal medular foi realizada. O sacrifício foi realizado com 139 dias de gestação para avaliação fetal. O sistema nervoso central foi submetido a ressonância magnética (REMA) post-mortem e a coluna foi submetida a exame anátomo-patológico. RESULTADOS: O defeito foi criado em 13 fetos e 5 sobreviveram. A idade gestacional média da necropsia foi de 121,6 dias (variando de 93 a 145 dias). Macroscopicamente o defeito estava presente em 4 casos. A microscopia revelou achatamento da medula, com desaparecimento do canal medular e desarranjo da citoarquitetura medular com apoptose neuronal e/ou fusão da pia e dura-máter. A REMA demonstrou herniação do cerebelo para o canal cervical e siringomelia. CONCLUSÕES: O defeito produzido foi muito semelhante à meningomielocele em fetos humanos, levando inclusive à mal-formação de Arnold-Chiari. A REMA post-mortem, utilizada de forma inédita neste estudo, demonstrou ser uma excelente alternativa para demonstrar a presença da herniação do cerebelo. A técnica para produzir o defeito foi padronizada em nosso meio.

Biosynthetic cellulose induces the formation of a neoduramater following pre-natal correction of meningomyelocele in fetal sheep

PURPOSE: The aim of this study was to compare the effectiveness of two dura-mater substitutes, namely human acellular dermal matrix (HADM) and biosynthetic cellulose (BC), in repairing, in utero, surgically-induced meningomyelocele (MMC) in fetal sheep. METHODS: A neural tube defect was created at 74-77 days gestation in 36 fetal sheep. They were divided into 3 groups, the control group that did not receive pre-natal corrective surgery, and the other two groups that received corrective surgery using HADM (Group A) or BC (Group B). Both materials were used as a dura-mater substitutes between the neural tissue and the sutured skin. Correction was performed at gestation day 100 and the fetuses were maintained in utero until term. Sheep were sacrificed on gestation day 140. The fetal spine was submitted to macro and microscopic analysis. At microscopy, adherence of the material to the skin and neural tissue was analyzed. RESULTS: In the initial phase (pilot), experimentally-induced MMC was performed on 11 fetuses and 4 survived (37 percent). In the second phase (study), 25 fetuses received surgery and 17 survived (68 percent). In the study group, 6 fetuses did not undergo repair (control group), 11 cases were submitted to corrective surgery (experimental group) and one fetal loss occurred. Of the surviving cases in the experimental group, 4 constituted Group A and 6 in Group B. Macroscopically, skin and underlying tissues where easily displaced from the BC in all cases it was used; in contrast, HADM adhered to these tissues. To compare the adherence, 4 cases from Group A and 4 in Group B were studied. We observed adherence, host cell migration and vessel proliferation into the HADM all sections from Group A and this aspect was not present in any cases in Group B (p < 0.05). In Group B, we also observed that a new fibroblast layer formed around the BC thus protecting the medulla and constituting a "neoduramater". CONCLUSION: The use of BC...

OBJETIVO: Estudar os efeitos do emprego de dois materiais consideravelmente diferentes quanto à origem e custo na correção intra-uterina da meningomielocele criada experimentalmente em feto de ovino. MÉTODOS: Em 36 fetos de ovinos foi criado um defeito aberto de tubo neural, com 75 de dias de gestação. Os casos foram divididos em três grupos: o controle onde o defeito não foi corrigido, grupo corrigido A onde o material utilizado para cobrir a medula exposta foi a matriz dérmica humana acelular (MDHA) e o grupo corrigido B onde o material foi a celulose biossintética (CB). Após a correção realizada com 100 dias, os fetos eram mantidos intra-útero até o termo da gestação. Os sacrifícios foram realizados com 140 dias e a coluna fetal era submetida à análise macro e microscópica onde foi observada a aderência dos materiais à pele, medula ou tecido nervoso remanescente. RESULTADOS: Na fase inicial (piloto), 11 fetos foram operados e 4 sobreviveram (37 por cento). Na segunda fase (estudo) 25 fetos foram operados e 17 sobreviveram (68 por cento). No grupo de estudo, 6 fetos não foram submetidos à correção (grupo controle), 11 casos foram corrigidos e ocorreu 1 perda fetal. Do total de 10 casos, 4 constituíram o grupo A e 6, o grupo B. A macroscopia observou-se deslizamento da pele e tecidos subjacentes sobre a CB em todos os casos onde ela foi empregada e isto não ocorreu em nenhum dos casos onde a MDHA foi utilizada. Para comparar a aderência, foram considerados 4 casos do grupo A e 4 do grupo B. A aderência, caracterizada pela migração de células do hospedeiro e proliferação de vasos para dentro da MDHA, foi observada em 100 por cento dos casos do grupo A e em nenhum caso no grupo B (p < 0,05). No grupo B observou-se formação de uma camada de fibroblastos ao redor do material, protegendo a medula, caracterizando a formação de uma "neoduramater". CONCLUSÃO: A utilização da película de celulose biossintética parece ser mais adequada como substituto...

Experimental observation of three-color optical quantum correlations.

Quantum correlations among bright pump, signal, and idler beams produced by an optical parametric oscillator, all with different frequencies, are experimentally demonstrated. We show that the degree of entanglement between signal and idler fields is improved by using information on pump fluctuations. To our knowledge this is the first observation of three-color optical quantum correlations.

Influência do movimento de alargamento contínuo ou alternado no desgaste das paredes de canais artificiais / Influence of automated handpieces with alternate motion and continuos rotation in simulated canals

O objetivo do trabalho é avaliar se o movimento de alargamento como giro contínuo obtido por meio de contra-ângulo redutor de velocidade acoplado em um motor elétrico e o movimento de alargamento com giro alternado obtido por meio de um contra-ângulo especial acoplado em motor elétrico, empregando-se instrumentos endodônticos de aço inoxidável (FlexoFile) e de níquel-titânio (K³ e Nitiflex) exercem influência no desgaste das paredes no segmento apical curvo de canais artificiais. Para a avaliação do desgaste foram realizadas fotografias digitais pré e pós-operatórias por meio de uma câmera digital que captou as imagens com o auxílio de um referenciador fotográfico que garantiu que as imagens sempre estivessem no mesmo plano, preservando assim, a padronização das fotografias. Em funçao dos resultados, concluimos que a natureza da liga metálica (n=NiTi ou aço inoxidável) dos instrumentos endodônticos empregados assim como o movimento de alargamento contínuo ou alternado gerados por meios mecânicos não interferiram nos resultados obtidos.

Foraminiferal responses to polluted sediments in the Montevideo coastal zone, Uruguay.

A study of foraminiferal assemblages was carried out in 24 sediment samples collected from the Montevideo coastal zone (south-eastern coastal region of South America) to assess the response of the benthic foraminifera to the polluted sediments. The area is affected by different pollutants such as sewage, hydrocarbons and heavy metals derived from different sources. Biological data were analyzed with multivariate techniques of cluster analysis and a principal component analysis (PCA) was performed for abiotic factors. The results allowed the recognition of different species assemblages corresponding to different sub-environments, which reflected the prevalent ecological conditions. The Montevideo Bay, particularly, its inner part showed an extremely poor foraminiferal fauna-including a totally azoic station-and high percentages of abnormal tests, when compared with the adjacent Punta Carretas and Punta Yeguas zones. Mean faunal density showed a strong relationship with organic matter, oxygen and heavy metal concentrations, as well as redox potential and pH values of each sub-environment. Although the adjacent zones presented a moderate pollution degree, it was noticed that a positive effect on the foraminiferal density specially on Ammonia tepida, caused by the sewage pipe located in Punta Carretas, a pure organic contamination. Differences among foraminiferal assemblages seemed to be related to the combined action of the several kinds of pollutants and the natural abiotic variables, like the rapid salinity changes that occurred in this area.

Validação do feto ovino como modelo experimental para o defeitomeningomielocele humana: estudo piloto / Validation of the ovine fetus as an experimental model for the human myelomeningocele defect: a pilot study

O objetivo deste trabalho foi produzir um defeito semelhante meningomielocele humanaem feto de ovinos, validando este modelo experimental, em nosso meio. Estudo prospectivo com 12 ovelhas de cruzamento das raças Hampshire e Down, onde um defeito na coluna foi criado cirurgicamente com 75 a 77 dias de gestação. A técnica consistiu emhisterotomia com exposição das patas traseiras e cauda até a metadeda coluna fetal. Foram retirados pele, musculatura paravertebral e quatro arcos vertebrais posteriores, expondo a medula. A dura foi aberta e uma incisão até o canal medular foi realizada. O sacrifício foi realizado com 139 dias de gestação para avaliação fetal. O sistemanervoso central foi submetido a ressonância magnética post-morteme a coluna foi submetida a exame anatomopatológico. O defeito foi criado em 13 fetos e 5 sobreviveram. A idade gestacional média da necropsia foi de 121,6 dias (variando de 93 a 145 dias).Macroscopicamente, o defeito estava presente em quatro casos. A microscopia revelou achatamento da medula, com desaparecimentodo canal medular e desarranjo da citoarquitetura medular com apoptose neuronal e/ou fusão da pia e dura-máter. A ressonância magnética demonstrou herniação do cerebelo para o canal cervical e siringomelia. Conclusões: O defeito produzido foi muito semelhante à meningomielocele em fetos humanos, levando inclusive àmalformação de Arnold-Chiari. A ressonância magnética postmortem,utilizada de forma inédita neste estudo, demonstrou ser uma excelente alternativa para demonstrar a presença da herniação do cerebelo. A técnica para produzir o defeito foi padronizada em nosso meio.

Efeitos da estimulação com corrente elétrica contínua pulsátil sobre as propriedades eletrofisiológicas atriais: estudo experimental da fibrilação atrial em cães / Effects of stimulation with pulsatile continuous electrical current on atrial electrophysiological properties: experimental study of atrial fibrillation in dogs

OBJETIVO: Avaliar se a estimulação atrial com corrente elétrica contínua pulsátil induz fibrilação atrial e os seus efeitos sobre as propriedades eletrofisiológicas atriais e as alterações histológicas atriais. MÉTODOS: Foram submetidos à toracotomia lateral direita 22 cães e implantados eletrodos de marcapasso no sulcus terminalis (ST), apêndice atrial direito (ADb) e na região póstero-inferior do átrio esquerdo (AE); um par de eletrodos foi suturado na auriculeta direita para estimulação com bateria alcalina de 9 Volts conectada a uma sistema (LM 555) que transforma a energia contínua linear da bateria em corrente contínua pulsátil, durante 60 min. A biópsia epicárdica atrial foi realizada antes e após a estimulação atrial. RESULTADOS: Não foram observadas diferenças nas durações dos períodos refratários efetivos atriais. Os tempos de condução intra-atrial, interatrial, bem como dos extra-estímulos atriais também prolongaram-se. A duração dos eletrogramas atriais prolongou-se durante ritmo sinusal e estimulação atrial programada; em 68 por cento dos cães a fibrilação atrial foi induzida e sustentou-se. Foram observados edema intersticial e bandas de contração celular no subepicárdio à microscopia óptica, e intensa desorganização miofibrilar e aumento do tamanho das mitocôndrias à microscopia eletrônica. CONCLUSÃO: Esta técnica de estimulação atrial induz fibrilação atrial e provoca modificações atriais que aumentam sua vulnerabilidade para o surgimento de fibrilação atrial.

Successful fetal surgery for the repair of a 'myelomeningocele-like' defect created in the fetal rabbit.

OBJECTIVE: To study the correction of a 'myelomeningocele-like' defect in fetal rabbits. METHODS: Twelve pregnant rabbits had a spinal defect surgically created in 40 of their fetuses at 23 days of gestation. Immediate repair was performed in 30 fetuses (group I), and 10 remained uncorrected (group II). After 30 days, the fetuses were harvested and the anatomopathological aspects where compared using Fisher's exact test. RESULTS: Three different techniques to apply a cellulose graft were used for correction in 8 (technique A), 7 (technique B), and 15 animals (technique C), but only one (technique C) was successful. The survival rate at 30 days was 66.7% (10/15) in group I and 80% (8/10) in group II. A 'myelomeningocele-like' defect was present in all fetuses in group II, while in group I the defect was successfully repaired in 80% of the surviving fetuses (p < 0.01). CONCLUSION: The surgically created spinal defect was successfully repaired, and also the fetal rabbit could be established as a model for the study of intrauterine correction of a myelomeningocele-like defect.

Estudo de uma nova técnica para criação cirúrgica de um defeito semelhante a meningomielocele em fetos de coelhos / Study of a new technique to surgical create of a myelomeningocele like defect in the fetal rabbit

OBJETIVO: Avaliar a sobrevida fetal usando uma nova técnica cirúrgica para criação de um defeito semelhante a meningomielocele em fetos de coelho. MÉTODOS: Foram utilizadas seis coelhas da linhagem Nova Zelândia que tiveram um defeito espinhal criado em seus fetos no 23º dia de gestação. O defeito foi criado em 19 fetos e a tentativa de correção foi feita em 15 casos (grupo I), 4 fetos permaneceram sem correção (grupo II). No 30º dia de gestação, os fetos foram submetidos a avaliação anátomo-patológica. RESULTADOS: No 30º dia a meningomielocele estava presente em todos os fetos sobreviventes. A sobrevida total foi de 73,68 por cento (14/19), 11 fetos sobreviveram no grupo I, e 3 no grupo II. CONCLUSÃO: A técnica modificada apresenta sobrevida fetal satisfatória, no modelo experimental de criação de defeito espinhal em fetos.

A different technique to create a 'myelomeningocele-like' defect in the fetal rabbit.

OBJECTIVE: To evaluate the fetal survival rate using a modified technique to surgically create a 'myelomeningocele-like' defect in a rabbit model. METHODS: Six white New Zealand rabbits had a spinal defect created in their fetuses at 23 days of gestation. At 30 days of gestation, the fetuses were harvested for anatomo-pathologic evaluation. RESULTS: The defect was created in 19 fetuses and an attempt to correct it was made in 15 cases (group I), and 4 fetuses where left without correction (group II). At 30 days, a 'myelomeningocele-like' defect was present in all surviving fetuses. The total survival rate was 73.68% (14/19); 11 fetus survived in group I and 3 in group II. CONCLUSION: The technical modifications, including fetal positioning and exposure of its back prior to the incision of the lamina, associated with a different technique for myometrium closure, offer an alternative and probably safer method to surgically create a spinal defect in the fetal rabbit.

Regional mild hypothermia in the protection of the ischemic brain

Objective: To demonstrate that mild hypothermia can be a protective element when an ischemic onset occurs in rabbit brains. Methods: A rabbit model of focal ischemia was used to test the protection provided by mild hypothermia regionally produced by means of the placement of ice bag on the scalp of a hemicranium which has had previously its bone removed. Twenty New Zealand White rabbits were divided into two groups as follows: (A) a control group where an ischemic lesion was produced by coagulation of the middle cerebral artery and (B) a brain protected group where mild hypothermia was provided during 80 to 100 minutes after the same ischemic lesion. The brains slices were stained with 2,3,5-Triphenyletrazolium (TTC). The sections were photographed with a digital camera and the infarct volume was measured through a computer program. Results: The average of infarct volume was 70.53 mm3 in the control group. In the protected group, the average of infarct volume was 41,30 mm3 only in five animals. Five animals of this group did not demonstrate macroscopically and microscopically infarct area. Conclusions: We concluded that mild hypothermia regionally produced may protect ischemic brains of rabbits.

Atividade da própolis sobre as bactérias isoladas da cavidade bucal / Effects of propolis on bacteria isolated from oral cavity

A própolis é conhecida desde a antiguidade por suas propriedades antibacterianas, cicatrizantes, antifúngicas, entre outras. Neste estudo foi pesquisada a atividade da própolis sobre bactérias recém-isoladas da cavidade bucal: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans e Lactobacillus sp. As amostras foram semeadas em meio de cultura adequado a cada tipo de bactéria, e contendo própolis em concentraçöes que variavam de 1 a 10mg/ml. Foi observada atividade antibacteriana evidente sobre as bactérias citadas acima, na seguinte ordem de sensibilidade: S. mutans > Lactobacillus sp > S. aureus > S. epidermidis.

Atividade antibacteriana da própolis / Antibacterial activity of propolis

A própolis já é conhecida há séculos por suas potencialidades terapêuticas, sendo considerada como antibiótico natural com atividade confirmada por várias pesquisas. A literatura atual relata atividades antibacteriana, antioxidante, antiparasitária, antifúngica e cicatrizante. A açäo antibacteriana foi alvo de nossos estudos no presente trabalho. Os extratos alcoólicos da própolis (EEP), após sofrerem diluiçöes decimais (1/10, 1/100, 1/1000, 1/10000, 1/100000), foram colocados em contato com cepas bacterianas tipadas e padronizadas com aproximadamente 150 UFC/ml por período de 2 horas, sendo plaqueadas a seguir pela Técnica do "Pour Plate"; novo plaqueamento foi realizado após 4 horas de contato EEP e suspensäo bacteriana, sendo todas as placas incubadas a seguir, a 37 graus Celsius por 24 horas. Os resultados foram anotados por contagem de UFC/ml e comparaçäo como número inicial de UFC/ml. Os resultados obtidos indicam atividade antibacteriana dos EEP utilizados no experimento contra as bactérias Gram positivas e uma menor, mas näo menos significante, atividade contra bactérias Gram negativas.