Effects of cryoprotectants and low temperatures on hatching and abnormal embryo development of Prochilodus lineatus (Characiformes: Prochilodontidae)

This study evaluated the effect of the cryoprotectants and the low temperatures on the embryonic development of Prochilodus lineatus, describing their main morphological alterations. On chilling sensitivity test, the survival rates at the twenty somites stage (20S) were 53.6% at 0ºC, and 100% in 5ºC. To test toxicity, the embryos were exposed to a graded series of 1,2-Propanediol (PROP), dimethyl sulfoxide (Me2SO4) and glycerol (GLY), terminating in a solution of high osmolarity. There was no significant difference in the embryos survival of toxicity test between series of PROP and Me2SO4 in the 6S and 20S. In the cooling protocols, were evaluated the effects of low temperature associated with cryoprotectants. At 5ºC, PROP showed survival rates above 75% in the gastrula stage (G) and above 90% in the 6S and 20S stages. High rates of abnormalities were observed, and the most recurrent were: small bodies, fins presenting uncontrolled cell growth, membrane rupture, and retraction. These results demonstrate the need to use cryoprotectant solutions, even when there is no ice nucleation, and, on the other hand, shows that high cryoprotectant concentrations promote numerous morphological lesions, compromising normal embryonic development.(AU)

Este estudo avaliou os efeitos dos crioprotetores e das baixas temperaturas no desenvolvimento embrionário de Prochilodus lineatus, descrevendo suas principais alterações morfológicas. Nos testes de sensibilidade ao frio, as taxas de sobrevivência, no estágio de vinte somitos (20S), foram de 53,6% a 0ºC e 100% a 5ºC. Nos testes de toxicidade, os embriões foram expostos a uma série graduada dos crioprotetores: 1,2-Propanediol (PROP), dimetilsulfóxido (Me2SO4) e glicerol (GLY), terminando em uma combinação de alta osmolaridade. Não houve diferença significativa na sobrevivência dos embriões nas séries do PROP e Me2SO4 nos estágios de 6S e 20S. Nos protocolos de resfriamento, foram avaliados os efeitos da baixa temperatura associados as séries crioprotetoras. A 5ºC, o PROP apresentou taxas de sobrevivência acima de 75% no estádio de gástrula (G) e acima de 90% nos estádios 6S e 20S. Foram observadas altas taxas de anormalidades sendo as mais recorrentes: corpos pequenos, nadadeiras apresentando crescimento celular descontrolado, ruptura da membrana e retração vitelínica. Estes resultados demonstram a necessidade do uso das soluções crioprotetoras, mesmo não havendo nucleação de gelo e, em contrapartida, demonstra que as elevadas concentrações crioprotetoras promovem numerosas lesões morfológicas, comprometendo o desenvolvimento embrionário.(AU)

Efecto de la concentración de crioprotectores sobre la viabilidad post vitrificación de embriones murinos (mus musculus) / Effect of cryoprotectant concentration on the post vitrification morphological viability of murine embryos (mus musculus)

Con la finalidad de determinar la mejor solución de vitrificación (SV), usando Etilenglicol (EG), Glicerol (G) y Sucrosa (SUC), se evaluó la apariencia morfológica post vitrificación de embriones murinos (Mus musculus). Ocho mezclas diferentes de crioprotectores fueron evaluadas, con las siguientes concentraciones: SV1: 0% de crioprotectores; SV2: 50% EG; SV3: 50% G; SV4: 50% SUC; SV5: 25% EG + 25% G; SV6: 50% EG + 0,3M SUC; SV7: 50% G + 0.3M SUC y SV8: 25% EG + 25% G + 0,3M SUC. El mayor número de embriones (94,7%) con apariencia morfológica normal, fueron los equilibrados con SV5. No hubo diferencia significativa entre la SV8 (88,9%) y la SV5. Mientras que los embriones criopreservados con las soluciones restantes, presentaron viabilidad morfológica más baja (p<0,05). Estos resultados sugieren que la SV5 provee mejor tolerancia al proceso de vitrificación, observándose en los embriones la más alta viabilidad y la más baja frecuencia de anormalidades morfológicas. Estos hallazgos contribuyen de manera importante, en la selección de los crioprotectores para la vitrificación.

In order to determine the best vitrification solution (VS), using ethylene glycol (EG), glycerol (G) and sucrose (SUC), the post vitrification morphology in murine embryos (Mus musculus) was evaluated. Eight different mixtures of these chemicals, with the following concentrations: VS1: 0%; VS2: 50% EG; VS3: 50% G; VS4: 50% SUC; VS5: 25% EG + 25% G; VS6: 50% EG + 0.3M SUC; VS7: 50% G + 0.3M SUC and SV8: 25% EG + 25% G + 0.3M SUC, were used. VS5 was the solution with the highest percentage (94,7%) of embryos with normal morphology. There were no significant differences between the VS8 (88.9%) and VS5. However, embryos cryopreserved with the other solutions had a lower morphological viability (p<0.05). These results suggest that VS5 provides embryos with better tolerance to the vitrification process, because a higher viability and lower frequency of morphological abnormalities were present. These findings provide details of great importance to the selection of cryoprotectants for vitrification.

Embriogénese: alterações morfológicas e crescimento desorganizado / Embryogenesis: Morphological Alterations and Disorganized Growth

A ocorrência de abortos espontâneos tem uma taxa de incidência elevada. Cerca de 15 a 20 % das gravidezes clinicamente reconhecidas terminam em aborto espontâneo, sendo a causa mais comum as anomalias cromossómicas. Foi objectivo avaliar as alterações morfológicas que mais frequentemente ocorrem no grupo dos crescimentos desorganizados (CD) (classificação de Poland et al.). Foram estudados 75 casos de abortos espontâneos, classificados histologicamente em crescimento desorganizado; subdividido em 4 tipos: CD1, CD2, CD3 e CD4. Foram consideradas as seguintes características morfológicas–macroscópicas: embrião; cordão umbilical; saco gestacional–intacto, roto e fragmentado; e crescimento (semanas de idade gestacional (IG)); e – microscópicas: córion; aspecto das vilosidades; estroma (edema, vasos, celularidade), trofoblasto vilositário e extravilositário; e desenvolvimento (semanas de IG). Da amostra, 29 casos correspondiam a CD1 —saco gestacional intacto contendo fluido mucóide, 32 a CD2 –embrião sem estruturas externas reconhecíveis, 8 a CD3 –embrião apenas com evidência dos pólos cefálicos e caudal, 6 a CD4— embrião com evidência de pólos cefálico e caudal; e outras estruturas externas reconhecíveis. À semelhança de outros autores, na nossa série, a hipoplasia do córion, a irregularidade do contorno vilositário, o edema e a hipovascularização foram também as alterações mais frequentes. Estes critérios poderão ter valor “preditivo” na classificação morfológica (diagnóstica) podendo orientar no aconselhamento genético de futuras gravidezes

The occurrence of spontaneous abortions has a highincidence rate. About 15 to 20% of the pregnanciesclinically recognized finish in spontaneous abortion,being the most common cause the chromosomalabnormalities.It was aim to evaluate the morphologic alterationsthat more frequently happen in the group of thegrowth disorganized (GD) embryos (classification ofPoland et al.).Seventy-five cases of spontaneous abortion werestudied, classified histologically in disorganized growth; subdivided in 4 types: GD1, GD2, GD3 and GD4. Thefollowing morphologic characteristics were considered -macroscopic: embryo; umbilical cord; gestational sac -intact, ruptured and fragmented; and growth (weeks ofgestational age); and - microscopic: chorion; aspect ofthe villi; stroma (oedema, vessels and cellularity); villous and extravillous trophoblast; and development (weeks of gestational age).Of the studied cases, 29 corresponded to GD1 —emptygestational sac containing mucoid fluid, 32 GD2- embryowithout recognizable external structures, 8 GD3 -embryojust with evidence of the cephalic and caudal poles, 6GD4— embryo with evidences of cephalic and caudalpoles, and others recognizable external structures.Like other authors, in our series, the hipoplasia of thechorion, the irregularity of the villi contour, the oedema and the hipovascularization were also the most frequent alterations.These criteria can have “predictive” value in themorphologic (diagnostic) classification and also couldprove some guide in the genetic consulting of future pregnancies (AU)

Knockout mice lacking cPGES/p23, a constitutively expressed PGE2 synthetic enzyme, are peri-natally lethal.

Cytosolic prostaglandin (PG) E synthase (cPGES) is constitutively expressed in various cells and regulates cyclooxygenase (COX)-1-dependent immediate PGE(2) generation. Its primary structure is identical to co-chaperone p23, a heat shock protein 90 (Hsp90)-binding protein. We have revealed that Hsp90 regulated both cPGES/p23 and its client protein kinase CK2. In this study, in order to examine the role of cPGES/p23 in vivo, we generated mice deficient in cPGES/p23 by a targeted disruption of exons 2 and 3, containing Tyr9, which is essential for catalytic activity. Heterozygotes are viable, fertile, and appear normal, despite a decrease in cPGES/p23 protein level. A generation of offsprings derived from intercrosses of cPGES/p23 homozygous mice revealed that 109, 247, and 10 pups were wild type, heterozygous, and homozygous, respectively; however, all homozygotes died at birth. The absence of viable null mutants, with heterozygotes and wild-type offspring obtained at a ratio of approximately 2:1, indicated that homozygosity for the cPGES/p23 null mutant leads to peri-natal lethality. Embryos homozygous for cPGES/p23-null had lower body weights than wild-type embryos, and abnormal morphology of skin and lungs. Moreover, the PGE(2) content in the lungs of cPGES/p23-null embryos was lower than that of the wild type. These results indicate that cPGES-derived PGES is involved in the normal development of mouse embryonic lung.

Abnormalities of caudal pharyngeal pouch development in Pbx1 knockout mice mimic loss of Hox3 paralogs.

Pbx1 is a TALE-class homeodomain protein that functions in part as a cofactor for Hox class homeodomain proteins. Previous analysis of the in vivo functions of Pbx1 by targeted mutagenesis in mice has revealed roles for this gene in skeletal patterning and development and in the organogenesis of multiple systems. Both RNA expression and protein localization studies have suggested a possible role for Pbx1 in pharyngeal region development. As several Hox mutants have distinct phenotypes in this region, we investigated the potential requirement for Pbx1 in the development of the pharyngeal arches and pouches and their organ derivatives. Pbx1 homozygous mutants exhibited delayed or absent formation of the caudal pharyngeal pouches, and disorganized patterning of the third pharyngeal pouch. Formation of the third pouch-derived thymus/parathyroid primordia was also affected, with absent or hypoplastic primordia, delayed expression of organ-specific differentiation markers, and reduced proliferation of thymic epithelium. The fourth pouch and the fourth pouch-derived ultimobranchial bodies were usually absent. These phenotypes are similar to those previously reported in Hoxa3(-/-) single mutants and Hoxa1(-/-);Hoxb1(-/-) or Hoxa3(+/-);Hoxb3(-/-);Hoxd3(-/-) compound mutants, suggesting that Pbx1 acts together with multiple Hox proteins in the development of the caudal pharyngeal region. However, some aspects of the Pbx1 mutant phenotype included specific defects that were less severe than those found in known Hox mutant mice, suggesting that some functions of Hox proteins in this region are Pbx1-independent.

Control of retinoic acid synthesis and FGF expression in the nasal pit is required to pattern the craniofacial skeleton.

Endogenous retinoids are important for patterning many aspects of the embryo including the branchial arches and frontonasal region of the embryonic face. The nasal placodes express retinaldehyde dehydrogenase-3 (RALDH3) and thus retinoids from the placode are a potential patterning influence on the developing face. We have carried out experiments that have used Citral, a RALDH antagonist, to address the function of retinoid signaling from the nasal pit in a whole embryo model. When Citral-soaked beads were implanted into the nasal pit of stage 20 chicken embryos, the result was a specific loss of derivatives from the lateral nasal prominences. Providing exogenous retinoic acid residue development of the beak demonstrating that most Citral-induced defects were produced by the specific blocking of RA synthesis. The mechanism of Citral effects was a specific increase in programmed cell death on the lateral (lateral nasal prominence) but not the medial side (frontonasal mass) of the nasal pit. Gene expression studies were focused on the Bone Morphogenetic Protein (BMP) pathway, which has a well-established role in programmed cell death. Unexpectedly, blocking RA synthesis decreased rather than increased Msx1, Msx2, and Bmp4 expression. We also examined cell survival genes, the most relevant of which was Fgf8, which is expressed around the nasal pit and in the frontonasal mass. We found that Fgf8 was not initially expressed along the lateral side of the nasal pit at the start of our experiments, whereas it was expressed on the medial side. Citral prevented upregulation of Fgf8 along the lateral edge and this may have contributed to the specific increase in programmed cell death in the lateral nasal prominence. Consistent with this idea, exogenous FGF8 was able to prevent cell death, rescue most of the morphological defects and was able to prevent a decrease in retinoic acid receptorbeta (Rarbeta) expression caused by Citral. Together, our results demonstrate that endogenous retinoids act upstream of FGF8 and the balance of these two factors is critical for regulating programmed cell death and morphogenesis in the face. In addition, our data suggest a novel role for endogenous retinoids from the nasal pit in controlling the precise downregulation of FGF in the center of the frontonasal mass observed during normal vertebrate development.

Mecanismo embrionário das malformações decorrentes de fármacos / Embrional mechanisms of malformations current of pharmacs

As malformações congênitas decorrentes de teratógenos atingem um ou mais folhetos, ou camadas germinativas, do embrião, originando alterações em sistemas orgânicos, entre os quais os mais atingidos são o cardiovascular, o osteolocomotor e o nervoso. Os tecidos interagem reciprocamente, ora induzindo, ora sendo induzido, através de mecanismos moleculares controlados por genes específicos da família sonic hedgehog, presentes nas células embrionárias em proliferação, onde o mesoderma intra-embrionário é o folheto-chave nestas induções. Neste trabalho, mais uma vez os autores chamam a atenção para a necessidade da prevenção primária das malformações congênitas, inclusive a análise do custo-benéficio em se administrar drogas às gestantes, sobretudo na saúde pública preventiva, no sentido de evitar que as malformações aconteçam

The usefulness of autopsies as a tool for teaching human embrilogy

Embryology is often difficult to teach because of the rapid, three-dimensional changes that occur simultaneously on a microscopic scale. A knowledge of normal and abnormal human development is important for understanding the pathophysiology, clinical treatment and surgical repair of malformations. In this study, we developed a method to enhance the comprehension of human embryology and its associated malformations. The strategy used macro-and-microscopical digital documentation of embryos, fetuses and neonates undergoing autopsy in the Department of Anatomical Pathology at the State University of Campinas. The images acquired were used in the Human Morpho-Physiology, course of the university´s medical curriculum. The embryology lectures were divided into two parts. In the first part, the development of the body´s structures was explained, while in the second, macro-and-microscopic images of selected autopsies were shown to the students, who were also encouraged to find and discuss the malformations and their clinical history, diagnosis and therapeutics. At the end of the course, the teaching material and the method used were evaluated using a questionnaire, interviews, and a test of the knowledge acquired during the lectures. Most of the students approved the method, and emphasized the importance of integration between basic and clinical disciplines. Their performance in the examination was also good

Fgf3 signaling from the ventral diencephalon is required for early specification and subsequent survival of the zebrafish adenohypophysis.

The pituitary gland consists of two major parts: the neurohypophysis, which is of neural origin; and the adenohypophysis, which is of non-neural ectodermal origin. Development of the adenohypophysis is governed by signaling proteins from the infundibulum, a ventral structure of the diencephalon that gives rise to the neurohypophysis. In mouse, the fibroblast growth factors Fgf8, Fgf10 and Fgf18 are thought to affect multiple processes of pituitary development: morphogenesis and patterning of the adenohypophyseal anlage; and survival, proliferation and differential specification of adenohypophyseal progenitor cells. Here, we investigate the role of Fgf3 during pituitary development in the zebrafish, analyzing lia/fgf3 null mutants. We show that Fgf3 signaling from the ventral diencephalon is required in a non-cell autonomous fashion to induce the expression of lim3, pit1 and other pituitary-specific genes in the underlying adenohypophyseal progenitor cells. Despite the absence of such early specification steps, fgf3 mutants continue to form a distinct pituitary anlage of normal size and shape, until adenohypophyseal cells die by apoptosis. We further show that Sonic Hedgehog (Shh) cannot rescue pituitary development, although it is able to induce adenohypophyseal cells in ectopic placodal regions of fgf3 mutants, indicating that Fgf3 does not act via Shh, and that Shh can act independently of Fgf3. In sum, our data suggest that Fgf3 signaling primarily promotes the transcriptional activation of genes regulating early specification steps of adenohypophyseal progenitor cells. This early specification seems to be essential for the subsequent survival of pituitary cells, but not for pituitary morphogenesis or pituitary cell proliferation.

Farmacoterapia en el embarazo y la lactancia / Drug therapy in pregnancy and breastfeeding

La prescripción de medicamentos y la automedicación de la mujer embarazada es un hecho conocido. En este articulo se analizan los cambios fisiológicos y farmacocinéticos que supone el embarazo y que pueden alterar los resultados de la medicación. Se analiza el rol de la placenta a la que ya no se la considera como una "barrera", sino como una vía de llegada de oxígeno, nutrientes y fármacos. Se define teratogénesis en sentido amplio y se describen los mecanismos más importantes de teratogenia. Se describen los períodos más críticos donde puede actuar un teratógeno. Se realiza un repaso crítico de la clasificación de la Food and Drug Administration (FDA). Por último se analizan algunos fármacos que deben ser usados con precauciones durante la lactancia y se dan una serie de normas de carácter general, tanto para la prescripción durante el embarazo, como durante la lactancia.

Trigeminal neuralgia associated with a primitive trigeminal artery variant: case report.

OBJECTIVE AND IMPORTANCE: A variant type of the primitive trigeminal artery (PTA) is a rare anomalous vessel that originates from the internal carotid artery and directly supplies the territory of the anteroinferior cerebellar artery and/or the superior cerebellar artery. We report a case of trigeminal neuralgia associated with this PTA variant, and we discuss the characteristics of this vessel. CLINICAL PRESENTATION: A 51-year-old woman presented with a 10-year history of left paroxysmal facial pain. Magnetic resonance angiography and cerebral angiography demonstrated that an aberrant vessel originating from the left internal carotid artery directly supplied the cerebellum, without a basilar artery anastomosis. INTERVENTION: Surgical exploration was performed via a left retrosigmoid approach. A loop of the aberrant vessel, which entered the posterior fossa through the isolated dural foramen, was compressing the trigeminal nerve. This aberrant vessel was displaced medially from the nerve with a prosthesis, with care to avoid kinking and avulsion of the perforating arteries. The patient's neuralgia resolved postoperatively. CONCLUSION: Although the PTA variant is frequently associated with intracranial aneurysms, it is extremely rare for the variant to lead to trigeminal neuralgia. During microvascular decompression surgery, surgeons should be careful to prevent injury of the perforating arteries arising from the PTA variant.

Interrupção legal em gestações com fetos portadores de patologias letais: aspectos epidemiológicos e emocionais / Legal abortion in pregnancies with lethal fetal abnormalities: epidemiological and emotional aspects

Analisar aspectos epidemiológicos e emocionais nos casos de interrupção legal de gestações de fetos portadores de malformações incompatíveis com sobrevida neonatal, atendidos no Programa de Medicina Fetal (PMF) do Centro de Atenção Integral à Saúde da Mulher (CAISM) - UNICAMP entre 1995 e 1999; investigar as gestações levadas a termo nas mesmas circunstâncias. Estudo retrospectivo e documental a partir dos prontuários de 153 gestantes atendidas no PMF com diagnóstico pré-natal de anomalias fetais incompatíveis com a vida. Variáveis estudadas: idade, estado civil, idade gestacinal (IG) de admissão, antecedentes gestacionais, planejamento da atual gestação, patologia fetal. Setenta pacientes (45,7 por cento) optaram pela interrupção da gravidez (grupo A) e 83 (54,3 por cento) pela continuidade (grupo B). Distribuição dos tipos de anomalia diagnosticados; anencefalia (43,2 por cento), patologia renal (22,2 por cento), malformações múltiplas (7,2 por cento), trissomia do cromossomo 18 (11,7 por cento), trissomia do cromossomo 13 (5,9 por cento), displasias esqueléticas (6,5 por cento) e gemelidade incompleta (3,2 por cento). Faixa etária das pacientes: 16 a 43 anos. A freqüência de primigestas e multíparas foram semelhantes. As interrupções autorizadas ocorreram entre o 2º e o 3º trimestre gestacional. A IG e o tipo de patologia fetal foram significativamente determinantes na opção (p=0,03 e p<0,001, respectivamente). Importância do diagnóstico precoce de malformações. A possibilidade de interrupção pode representar um fator tranqüilizador.

Prevençäo de malformações congênitas / Congenital malformations prevention

A idéia de escrever este artigo surgiu a partir da experiência didática, durante os últimos 22 anos, sobre temas referentes à embriologia geral (formaçäo do zigoto humano até o início do período embrionário) e embriologia especial (diferenciaçäo dos sistemas orgânicos), de um simpósio interno CAMU I - Unesa-2001 e, finalmente, da VIII Semana Científica da FMP, em 2002, sobre "Medicina: uma preocupaçäo com a saúde ou com a doença". Segundo a OMS (1999), o nível primário representa evitar que aconteça o modelo genético, o secundário representa evitar a recorrência das doenças entre as famílias e o terciário representa a reabilitaçäo dos problemas decorrentes destas doenças. A prevençäo das malformações congênitas, sobretudo, se faz mais essencial na saúde pública preventiva, ou seja, no nível primário, tendo como objetivo final proporcionar uma boa qualidade de vida ao portador da malformaçäo

Prenatal diagnosis of fetal tail and postabortum anatomical description.

Fetal ultrasound examination at 13 weeks of gestation demonstrated a homogeneously echogenic protrusion, or tail, 7 mm in length, in the sacral region. At 15 weeks, the ultrasound appearance was consistent with a regression of the tail and by 21 weeks it had completely disappeared. Severe intrauterine growth restriction with reduced uterine blood flow was diagnosed at 21 weeks and intrauterine death occurred at 24 weeks of gestation. Postmortem examination revealed a 4-mm caudal appendage which contained no vertebrae on radiography. The appendage was located under and behind the last sacral vertebra suggesting a true vestigial tail with a delayed process of regression.

Early sonographic detection of a 'human tail': a case report.

We report on a newborn in whom an echogenic protrusion arising in the caudal region was detected at 12 weeks' gestation. Subsequent ultrasound examinations at weeks 15 and 22 failed to demonstrate this finding. After birth, the infant was found to have a pilonidal sinus. The pilonidal sinus may represent a remnant of the embryonic appendage ('human tail') that usually disappears by the end of the 8th week of gestation. This case might support the theory of congenital pilonidal sinus origin.

Nosología actual de las duplicaciones embrionarias / Embryonic duplication. A nosologic update

Las formas anormales de gemelaridad constituyen un impactante fenómeno biológico y cuentan con una larga historia de concepciones erróneas, escaso conocimiento y una amplia y confusa sinonimia. En esta revisión se presenta la nosología actual de las duplicaciones embrionarias monocigóticas con énfasis en los gemelos unidos (GU), mediante la cual casi la totalidad de los casos de GU pueden ser adecuadamente diagnosticados. Dicha clasificación se basa en la orientación que guardan los discos embrionarios en etapas tempranas del desarrollo, resultando los 8 sitios de uniones conocidas tanto para las formas simétricas, parasitarias o ambas de GU: toracópagos, onfalópagos, cefalópagos, isquiópagos, parápagos, pigópagos, craneópagos y raquípagos. Además, se plantean las bases teóricas propuestas para el origen de las duplicaciones embrionarias, su epidemiología estimada a partir de alrededor de 1,300 reportes y su diagnóstico prenatal y diferencial. El entender la naturaleza aleatoria del fenómeno de gemelaridad, nos conduce a aceptar las limitaciones y avances en su tratamiento.

Fusión espleno-gonadal continua: reporte de un caso / Continuous splenic-gonadal fusion: case report

La fusión espleno-gonadal es una anomalia congénita rara. Es el resultado de la fusión de los esbozos esplénicos y gonadal durante el desarrollo embriológico. Se han descrito aproximadamente 90 casos en la literatura

Embriogénesis del sistema arterial coronario / Embryogenesis of coronary arterial system

La rapidez con la cual la circulación coronaria se establece durante el proceso embrionario es una de las características principales en el desarrollo cardiaco. Las arterias coronarias aparecen durante la transición entre la sexta y sétima semanas del desarrollo, como un brote angioblástico que una vez establecido se extiende rápidamente a través de la hoja epicárdica del corazón en formación. Presencia de vasos coronarios se logró comprobar con el estudio de doce embriones de seis, siete y ocho semanas, tratados con hematoxilina-eosina y cortados seriada, transversal y longitudinalmente, en los cuales se buscó la presencia de vasos coronarios en las regiones correspondientes a los surcos atrioventricular e interventricular hasta el ápex; así como en la desembocadura de la vena cava superior y los bordes agudo y obtuso. Pudiéndose concluir que para la novena semana, toda las ramas mayores de las arterias coronarias caraterísticas del corazón adulto, está prácticamente representadas

Influência da radiaçäo ionizante (bomba de cobalto) em embriöes de coelha na fase de pré-implantaçäo: influência no índice mitótico e malformaçöes no pólo embrionário / Influence of ionizing radiation (CO60) in pre-implant rabbit embryos: influence on mitotic index and embryonic pole malformations

Neste estudo avaliou-se o efeito da radiaçao ionizante em 12 coelhas (65 embrioes), em três diferentes momentos da gravidez: no momento do cruzamento / ovulaçao (hora zero), dois dias após e quatro dias após, com duas diferentes doses de irradiaçao: 5 cGy e 1O cGy. Seis coelhas (36 blastocistos) foram usadas como controles. O momento do cruzamento foi considerado a hora "zero". Após seis dias (ñ 60 minutos), os embrioes de cada coelha foram obtidos por lavagem do útero com meio de cultura. Os embrioes foram fixados em metanol por 48 horas, e corados com hematoxilina ácida de Mayer. Os seguintes parâmetros foram estudados: a - índice mitótico; b - malformaçoes do pólo embrionário. Nao se encontrou malformaçoes grosseiras do pólo embrionário. O índice mitótico foi alterado tanto pelo momento quanto pela dose irradiada.