Sexual determination and differentiation during embryonic and fetal development of New Zealand rabbit females / Determinación y diferenciación sexual durante el desarrollo embrionario y fetal de conejos hembras de Nueva Zelanda

The aim of this study was to know the embryonic and fetal development of the female rabbit genital system (Oryctolagus cuniculus), describing its main phases and the moment of sexual differentiation. Eleven pregnant New Zealand female rabbits were used in different gestational phases. The day of coitus was determined as day 0. For each stage a minimum of two animals was considered. The samples were obtained every two days from the ninth day post-coitus (dpc) until the 28th dpc. The gestational period was divided in two: animals with undifferentiated sex (group 1) and animals with differentiated sex (group 2). The ages of embryos and fetuses were estimated through the crown-rump method. Subsequently, embryos and fetuses were dissected, fixed and processed to be embedded in paraffin (Histosec). The histological analysis was performed on sections stained with hematoxylin and eosin. Immunohistochemical analysis to determine sexual differentiation was performed on samples from the 16th, 18th and 28th dpc. Desert Hedgehog (Dhh) and Indian Hedgehog (Ihh) primary antibodies, respectively, were used to identify cells of the male and female germinal epithelium. The immunohistochemical results showed that at the 16th dpc, female sexual differentiation was evident, since positive expression of the Ihh protein was observed. Sexual differentiation was obtained through histological analysis on the 18th dpc and through anatomical observation of the external genitalia on the 24th dpc. Knowing the characteristics of the embryonic and fetal development of the female rabbit genital system as well as the moment of sexual differentiation make it possible to establish bases for future research that address the physiology and pathology of these organs. Thus, any alteration in the chain of events of sexual determination and differentiation must search for an explanation from the knowledge of the possible normal mechanisms affected.

El objetivo de esta investigación fue conocer el desarrollo embrionario y fetal del sistema genital femenino de conejo (Oryctolagus cuniculus), describiendo sus principales fases y el momento de la diferenciación sexual. Se utilizaron 11 conejos hembras gestantes neozelandesas, en diferentes fases gestacionales. El día del coito se determinó como día 0. Para cada etapa fue considerado un mínimos de dos animales. Las muestras fueron obtenidas cada dos días, a partir del noveno día post-coito (dpc) hasta el 28 dpc. El periodo gestacional fue dividido en dos: animales con sexo indiferenciado (grupo 1) y, animales con sexo diferenciado (grupo 2). Las edades de los embriones y los fetos fueron estimadas a través del método de crown-rump. Posteriormente, embriones y fetos fueron disecados, fijados y procesados para su inclusión en parafina (Histosec). El análisis histológico se realizó en secciones teñidas con Hematoxilina y Eosina. El análisis inmunohistoquímico para determinar la diferenciación sexual fue realizado en muestras de 16, 18 y 28 dpc. Para identificar células del epitelio germinativo masculino y feminino se utilizaron los anticuerpos primarios Desert Hedgehog (Dhh) e Indian Hedgehog (Ihh), respectivamente. Los resultados inmunohistoquímicos mostraron que a los 16 dpc se evidenció diferenciación sexual femenina, ya que se observó expresión positiva de la proteína Ihh. La diferenciación sexual, a través del análisis histológico fue obtenida a los 18 dpc y a través de la observación anatómica de los genitales externos a los 24 dpc. Conocer las características del desarrollo embrionario y fetal del sistema genital femenino de conejo, así como, el momento de la diferenciación sexual, permiten sentar bases para futuras investigaciones que aborden la fisiología y patología de estos órganos. Así, cualquier alteración en la cadena de eventos de la determinación y diferenciación sexual deberá buscar una explicación a partir del conocimiento de los posibles mecanismos normales afectados.

Transitando de embrión a feto: la metamorfosis de los cordados / Transiting from embryo to fetus: the metamorphosis of the chordata

Durante el período del desarrollo conocido como prefetal, el embrión cambia sus características ictiomórficas comunes a todos los vertebrados y adquiere gradualmente las formas propias de la especie que representa. Durante este período se forma la cara, involucionan los arcos faríngeos (branquiales) formándose el cuello, y aparecen los miembros. Se constituye, además, la hernia umbilical fisiológica, que consiste en la presencia de asas intestinales dentro del cordón umbilical. El sistema nervioso origina las vesículas telencefálicas, el diencéfalo, mesencéfalo, metencéfalo, y mielencéfalo. Este periodo corresponde a una etapa de máxima susceptibilidad ante los teratógenos que pueden generar malformaciones en todas las especies animales. El objetivo del presente trabajo es presentar los principales eventos acontecidos durante el periodo prefetal, además de una visión y opinión de los autores, proponiendo una nueva denominación a la etapa: periodo metamórfico.

During the period of development known as prefetal, the embryo changes its ictiomorphic characteristics common to all vertebrates and gradually acquires the proper forms of the species it represents. During this period the face is formed, the pharyngeal arches (branchial) involute forming the neck, and the limbs appear. In addition, the physiological umbilical hernia is constituted, which consists of the presence of intestinal loops inside the umbilical cord. The nervous system originates the telencephalic vesicles, the diencephalon, mesencephalon, metencephalon, and myelencephalon. This period corresponds to a stage of maximum susceptibility to teratogens that can generate malformations in all animal species. The objective of this paper is to present the main events that took place during the preferential period, as well as a vision and opinion of the authors, proposing a new name for the stage: metamorphic period.

Complicaciones obstétricas y neonatales del hipotiroidismo / Obstetrics and neonatal complications of hypothyroidism

Las patologías tiroideas son frecuentes y afectan alrededor del 10% de la población fértil femenina. El hipotiroidismo y la enfermedad tiroidea autoinmune traen aparejados trastornos de la fertilidad e implantación y desarrollo del embarazo. Durante el embarazo la glándula tiroides es puesta a prueba, poniéndose en marcha distintos mecanismos adaptativos. Se debe resaltar la importancia de un aporte suficiente de yodo antes y durante el embarazo. El adecuado funcionamiento tiroideo, tanto materno como fetal, juegan un rol fundamental para la normal evolución del embarazo y del desarrollo neuropsicointelectual del feto, ya que una disminución aún leve de la función tiroidea en la primera mitad del embarazo puede tener secuelas a largo plazo. Las hormonas tiroideas son fundamentales para el normal desarrollo del SNC y del cerebro fetal. Además de las complicaciones fetales, las pacientes hipotiroideas tienen mayores complicaciones en el embarazo tales como aborto, parto prematuro, retardo del crecimiento intrauterino y bajo peso al nacer. Sería ideal que la paciente hipotiroidea programe su embarazo, se halle adecuadamente tratada y con un control estricto durante el embarazo. Si bien no hay consenso para el screnning de rutina, hay grupos que postulan la utilidad de incluir un dosaje de TSH y ATPO en el primer trimestre del embarazo. El diagnóstico precoz y su adecuado tratamiento evitarán complicaciones muchas veces irreversibles en el embarazo y en el desarrollo neurológico fetal.

Study about the development of the temporomandibular joint in the human fetuses / Estudio del desarrollo de la articulacion temporomandibular en fetos humanos

The temporomandibular joint (TMJ) is a highly specialized articulation that differs from all the other synovial articulations for many reasons. In children, different from what we observe in adults, these articulations have rarely been studied under the morphofunctional aspect, mainly in the embryonary and fetal stages. In this study 10 fetuses with ages varying from 16 to 39 weeks of intrauterine life were used, and it could be observed that the fibers and thickness of the articular disc, as well as the articular capsule and the condylar process, suffer modifications according to age. It was also observed that the superior head of the lateral pterygoid muscle inserts itself in the articular disc and capsule in all the ages studied. Also, the maturation of the articular tissues, especially of the articular disc, as well as, the associated muscles, suggests that the TMJ was able to carry out mandibular movements since the 24th week of intrauterine life.

La articulación temporomandibular (ATM) es una articulación altamente especializada que se distingue de todas las otras articulaciones sinoviales por muchas razones. En los niños, a diferencia de lo que se observa en los adultos, estas articulaciones muy pocas veces han sido estudiadas en el aspecto morfofuncional, principalmente, en las etapas embrionaria y fetal. Se utilizaron 10 fetos con edades que variaban entre 16 a 39 semanas de vida intrauterina. Se pudo observar que las fibras y espesor del disco articular, así como la cápsula articular y el proceso condilar. Sufren modificaciones en función de la edad. También se observó que la parte superior del músculo pterigóideo lateral se inserta en el disco y en la cápsula articular en todas las edades estudiadas. Por otra parte, la maduración de los tejidos articulares, especialmente del disco articular, así como, de los músculos asociados, sugiere que la ATM es capaz de llevar a cabo los movimientos mandibulares, desde la 24 ª semana de vida intrauterina.

Curva de crecimiento intrauterino de recién nacidos peruanos / Intrauterine growth curves to live peruvian newborns

Objetivos: Obtener curvas de crecimiento intrauterino peruanas y analizar la influencia del sexo fetal, paridad, talla materna y región natural, en el peso fetal. Método: Enrolamiento prospectivo de recién nacidos vivos sucesivos en 29 Hospitales peruanos, nacidos en 2005 y registrados en el Sistema Informático Peri-natal (SIP2000). Se utilizó técnicas antropométricas recomendadas por el CLAP-OPS/OMS. Diagnóstico de edad gestacional por fecha de última menstruación. Se seleccionaron recién nacidos (RN) sin factores de riesgo para retardo de crecimiento intrauterino. Distribución de los pesos de los recién nacidos en percentiles. Resultados: 50.568 RN vivos fueron seleccionados de 99.439 nacimientos. Se consideró los percentiles 10, 50 y 90 y se calculó los percentiles 2,5 y 5 para clasificar al RN pequeño para la edad gestacional en leve, moderado o severo. El 55,7 por ciento de los recién nacidos presentaron 39 ó 40 semanas de gestación, con peso promedio de nacimiento de 3.295 y 3.400 gramos, con el percentil 10 de peso de 2750 y 2875 gramos, respectivamente. La multiparidad, talla materna alta, sexo fetal masculino y nacer en la costa produjeron peso de nacimiento significativamente mayores, entre las semanas 36 a 42 semanas. Conclusiones: Se recomienda usar estas curvas de crecimiento intrauterino para una mejor clasificación de los recién nacidos peruanos.

Objectives: To obtain peruvian intrauterine growth curves and analyze the influence of fetal sex, parity, maternal height and natural región in the fetal weight. Method: Prospective enrolment of successive live newborns of 29 Hospitals of Peru, born in 2005, and registered in the Perinatal Information System (SIP2000). Anthropometrics techniques recommended by the CLAP-OPS/OMS were used. Diagnosis of gestational age was made by date of the last menstrual period. Were selected newborns without risk factors for intrauterine growth retardation. Newborns weights distribution was made in percentile curves. Results: 50,568 newborns were selected from 99,439 births. Percentile 10, 50 and 90 and was calculated, and also percentile 2.5 and 5 to classify the newborn small for gestational age in mild, moderate or severe. The 55.7 percent of newborns had 39 or 40 weeks of gestation, with an average birth weight of 3,295 and 3,400 g, with a 10 percentile of 2,750 and 2,875 grams, respectively. The multiparity, high maternal height, male fetal sex and birth on the coast produced significantly higher birth weight, between weeks 36 to 42 weeks. Conclusions: It is recommended to use these intrauterine growth curves for better classification of the peruvians newborns.

Regulation of mouse embryo development by autocrine throphic factors

Embryo development depends on maternal and embryonic factors. When occurs in vitro, embryos secrete factors that stimulate their development. The purpose of this study was to investigate the possible effects of embryos at morula stage on mouse embryo development in vitro. To obtain conditioned media (CM), morulas were cultured in groups of 5 (CM5) or 10 (CM10) in microdrops of Ham-Fl0 culture medium during 24h and later they were removed. Subsequently, 365 morulas were cultured in CM5 and CM10 or in Ham-F10 media (as control group). No differences in blastocyst formation could be found between embryos cultured for 24h in Ham-F1O, CM5 or CM10 (49.66, 53.04, 60.00% respectively). However, CM5 significantly increased differentiation in embryos cultured for 48h as compared to Ham-FlO medium (80.00% and 64.14 respectively). The CM5 caused a significant increase in the hatching rate compared to Ham-F10 evaluated at 78 and 96h of culture (66.96 vs. 52.41% and 70.43 vs. 55.17%, respectively). After 72, 78 and 96h of culture the hatching rate for embryos cultured in CM10 was significantly higher than that in Ham-F10 (64.76 vs. 47.59%, 67.62 vs. 52.41% and 73.33 vs. 55.17%, respectively). At 48h of culture, differences between CM5, CMl0 and Ham-F10 were not observed. These results suggest that preimplantational mouse embryos produce trophic factor/factors that enhance the differentiation and hatching process

Embryonic development time of Penilia avirostris Dana, 1852 in a tropical bay in Brazil

O tempo de desenvolvimento na câmara incubadora dos embriões do cladócero Penilia avirostris Dana, 1852, foi estimado a partir do zooplâncton coletado na água superficial da Baía de Guanabara, Brasil, diariamente, durante 15 dias. A cada dia, foi anotado o estágio de maturidade dos embriões de 90 fêmeas partenogenéticas. O tempo de desenvolvimento total (do ovo até o nascimento) variou de 2 a 3 dias, sendo a fase imatura (estágios I e IV) geralmente mais longa (2 dias) que as fases intermediárias e maturas (1 dia, estágios V a XII). Resultados similares foram obtidos com a equação de Bottrell, que leva em conta a temperatura da água.

Estimulación prenatal: el inicio de una educación ecológica del neocórtex / Prenatal stimulation: the beginning of an ecological education of neocórtex

La estimulación del desarrollo psicomotor e integral del feto se ha relacionado no sólo a mejor puntuación de estudios de evaluación y de CI, sino tambiÚn a una mejor relación madre y padres-hijo. Los sentidos que mas fßcil se pueden incorporar a la estimulación son el oído, a travÚs de la música, voces familiares, sonidos naturales como el mar, viento y canto de pßjaros. El otro sentido a estimular es el tßctil por medio de caricias o contacto con diferentes texturas naturales (agua, arena).

Embryo-endometrial proteases during early mammalian development.

In mammals, extensive remodeling of uterine endometrial matrix occurs during reproductive cycle and blastocyst implantation. This is regulated by a variety of molecules such as hormones, growth factors, cytokines and proteases. In this article, we review the current state of knowledge available on various proteases and their inhibitors functionally involved in the embryo-endometrial tissues and present some data on endometrial proteases in hamsters and rats during estrous cycle and early pregnancy. We demonstrate the presence of at least four gelatinolytic activities in endometrial samples, belonging to gelatinase-A and -B categories and their dependence on calcium/zinc ions for enzyme activity and, their interrelationships between zymogen and active forms. We believe that the embryo-endometrial proteases are essential for hatching of blastocysts and for the dynamic remodeling of endometrial tissues, occurring during the critical peri-implantation period.

Preliminary study on somatic cell nuclear transfer in rabbits in Thailand.

The objective of the study was to develop the somatic nuclear transfer technique by using rabbits as the model. The oocyte recipients aged 16 h post coitus were collected surgically from 20 superovulated rabbit doe with 28 and 40 mg Follicle Stimulating Hormone (FSH) after mating with a vasectomized male. The metaphase II plate and 1st polar body of oocyte was later aspirated by enucleated micropipette under an inverted microscope. A single donor cell; cumulus cell or cultured or frozen fibroblast cell from passage 1 to 9 were transferred to enucleated oocyte and fused with triple DC pulses, 3.2 kv, 20 micros. The fused embryos were cultivated in TCM 199 NaHCO3 + 10 per cent fetal calf serum (FCS) for 4 days. The cleavage rate (2-cell stage) was 37.2 per cent (32/86) from eight experiments, and 18.8 per cent (6/32) developed to the early morula stage. This study also indicated that the enucleation pipette and the somatic cell type influenced the success.

An interesting rare case of sirenomelia.

In sirenomelia the caudal tissues of the foetus fail to develop because of the "stealing" of blood by a vitelline vascular shunt from the distal aorta during embryogenesis interfering with foetal development. A 25 years old 2nd gravida delivered one full term premature grossly asphyxiated baby at BS Medical College on 24-10-1998. The examination of the dead foetus revealed no genitalia, no anal nor urethral opening and having a single lower limb with the single thigh and rudimentary leg. Skiagram of the foetus corroborated it to be a case of syrenomelia.

Hypokalemic paralysis in pregnancy.

Hypokalemic paralysis is an uncommon entity with varied etiology. Renal tubular acidosis is an unusual cause of this disorder. Its occurrence with pregnancy is rare. We report such a case and mention the implications of the association and review relevant literature breifly.

Influence of placental malaria infection on foetal outcome in the Gambia: twenty years after Ian Mcgregor.

Malaria infection in pregnancy has serious health consequences among mothers and offspring. The influence of placental malaria infection on foetal outcome was studied in a Gambian rural setting where few pregnant women take antimalarial chemoprophylaxis. During July-December 1997, three hundred thirteen mother-newborn pairs (singletons only) were consecutively recruited into a study of the effects of placental malaria infection on the outcome of pregnancy. Placental blood and tissue were collected at delivery. Babies were clinically assessed until discharge. The overall prevalence of placental malaria infection was 51.1% by placental histology and 37.1% by blood smear. The primigravid women were more susceptible to placental malaria than the multigravidae (65.3% vs 44.7%, p=0.01). Placental malaria was significantly associated with pre-term deliveryand intrauterine growth retardation (p<0.01), and there was a four-fold risk of delivering low-birth-weight babies if mothers had parasitized placentae [OR=4.42, 95% confidence interval (CI) 2.10-9.27]. A reduction of mean birth-weight of babies by 320 g was associated with placental malaria infection (p<0.001). Similarly, a two-fold risk of stillbirth delivery (OR=2.22, 95% CI 1.04-4.72) was observed among the infected mothers. The findings showed that there was still an overall poor foetal outcome associated with placental malaria infection. The findings of this study confirm the findings of an earlier study by McGregor in the Gambia that the low birth-weight rate is significantly higher if the placenta is parasitized. In addition, this study observed that the high stillbirth and prematurity rates were associated with placental malaria infection. The findings of the present study suggest undertaking of effective malaria-control strategies during pregnancy, such as use of insecticide-impregnated bednets, intermittent and early treatment for malaria, and antimalarial chemoprophylaxis, in the Gambia.

Birth weight patterns in rural undernourished pregnant women.

OBJECTIVE: To study the birth weight pattern in chronic as well as currently undernourished pregnant women. DESIGN: Prospective study of rural pregnant women by following eligible women. SETTING: Two adjoining blocks of rural Varanasi. METHOD: 3700 pregnant women from rural areas of Varanasi for whom data for anthropometry, hemoglobin, dietary intake, birth weight, fundal height and abdominal girth at 16 +/- 2, 28 +/- 2 and 36 +/- 2 weeks of gestation were recorded. Outcome measure was birth weight pattern of newborns. RESULTS: Of the births, 7.2% were < 2250 g and 27.4% < 2500 g. The weekly birth weight increments in gestation 36-42 weeks were 5-53 g, only. The fundal height did not increase during 35-39 weeks of gestation (lower by 5 cm as compared to normal). Nutrition supplement in the third trimester significantly increased fundal height and abdominal girth. Fundal height below 24.5 cm at 28 weeks of gestation (1368 women) was associated with higher low birth weight deliveries. CONCLUSION: Birth weight and fundal height increments during later pregnancy are low in undernourished pregnant women. Fundal height < 24.5 cm at 28 weeks of gestation identified women with higher risk for lowbirth weight infants. The prevalence of low birth weight was 27.4% and of prematurity was 6.6%.

Comparación del índice lecitina/esfingomielina versus fosfatidilglicerol en la evaluación de la madurez pulmonar fetal / Comparison of the lecitina/esfingomielina index versus fosfatidilglicerol in the evaluation of pulmonary fetal maturity

Reportamos el manejo y evolución de tres embarazadas cuyo estudio de índice de madurez pulmonar en el líquido amniótico mostró lecitina/esfingomielina (L/E) inmaduro (<2) con fosfatidilglicerol presente. Agregamos una revisión respecto de la capacidad de ambos test de predecir madurez pulmonar. Se ha descrito que cuando el fosfatidilglicerol está presente, aquellas paciente con un índice de L/E > 2 tiene una probabilidad cercana a cero de presentar enfermedad de membrana hialina neonatal. Por el contrario aquellos casos en los que el índice L/E presenta entre 1,5 y 1,9 la probabilidad de desarrollar la enfermedad es de un 3,4 por ciento. Para este último grupo recomendamos que, si la condición fetal y materna lo permite, la interrupción del embarazo sea diferida en una semana

Immunohistochemical Localization of Nerve Growth Factor, Glial Fibrillary Acidic Protein and Ciliary Neurotrophic Factor in Mesencephalon, Rhombencephalon, and Spinal Cord of Developing Mongolian Gerbil

The distribution of the nerve growth factor (NGF), the glial fibrillary acidic protein (GFAP) and the ciliary neurotrohic factor (CNTF) was performed in coronal sections of the mesencephalon, rhombencephalon and spinal cord in the developing Mongolian gerbils. Generally, NGF specifically recognizes neurons with the NGF receptor, whereas GFAP does the glia, and CNTF does the motor neurons. The receptor expression was examined separately in gerbils between embryonic days 15 (E15) and postnatal weeks 3 (PNW 3). The NGF-IR was first observed in the spinal cord at E21, which might be related to the maturation. The GFAP reactivity was peaked at the postnatal days 2 (PND2), while the highest CNTF-reaction was expressed at PNW 2. The GFAP stains were observed in the aqueduct and the spinal cord, which appeared to project laterally at E19. The CNTF was observed only after the birth and found in both the neurons and neuroglia of the substantia nigra, mesencephalon, cerebellum and the spinal cord from PND1 to PNW3. These results suggest that NGF, GFAP and CNTF are important for the development of the neurons and the neuroglia in the central nervous system at the late prenatal and postnatal stages.