Expression of Pax6 and Pax7 proteins during the central nervous system development in human embryos / Expresión de proteínas Pax6 y Pax7 durante el desarrollo del sistema central nervioso en embriones humanos

The family of paired box (Pax) genes encodes the transcription factors that have been emphasized for the particular importance to embryonic development of the CNS, with the evidence obtained from various animal models. Human embryos have rarely been available for the detection of the expression of Pax family members. In this study 32 human embryos of Carnegie (CS) stages 10-20 were investigated to find the differences in the expression of Pax6 and Pax7 proteins in different regions of the neural tube and the caudal spinal cord. The expression of Pax6 and Pax7, as determined by immunohistochemistry, showed a tendency to increase in the later stages of the development both in the spinal cord and the brain. Significantly weaker expression of Pax6 and Pax7 was observed at CS 10 as compared to the later stages. At CS 10-12 weak expression of Pax6 was noticed in both dorsal and ventral parts of the developing spinal cord, while the expression of Pax7 was restricted to the cells in the roof plate and the dorsal part of the spinal cord. At CS 14-20 in the developing spinal cord Pax6 and Pax7 were detected mostly in the neuroepithelial cells of the ventricular layer, while only weak expression characterized the mantle and the marginal layers. At the same stages in the developing brain Pax6 and Pax7 were expressed in the different regions of the forebrain, the midbrain and the hindbrain suggesting for their involvement in the differentiation of neurons in specific parts of the developing brain.

La familia de genes Pax del inglés (Paired box) codifica los factores de transcripción debido a la particular importancia en el desarrollo embrionario del SNC, con la evidencia obtenida de varios modelos animales. Rara vez han estado disponibles embriones humanos para la detección de la expresión de genes de la familia Pax. En este estudio, se investigaron 32 embriones humanos de Carnegie (CS) etapas 10-20 para encontrar las diferencias en la expresión de las proteínas Pax6 y Pax7 en diferentes regiones del tubo neural y la médula espinal caudal. La expresión de Pax6 y Pax7, según la inmunohistoquímica, se observó una tendencia a aumentar en las etapas posteriores del desarrollo, tanto en la médula espinal como en el cerebro. Se observó una expresión significativamente más débil de Pax6 y Pax7 en CS 10 en comparación con las etapas posteriores. En CS 10-12 se notó una expresión débil de Pax6 en las partes dorsal y ventral de la médula espinal en desarrollo, mientras que la expresión de Pax7 se limitó a células en la placa del techo y dorsal de la médula espinal. En CS 14-20 en la médula espinal en desarrollo, Pax6 y Pax7 se observó principalmente en las células neuroepiteliales de la capa ventricular, mientras que expresión débil se caracterizó en las capas marginales. En las mismas etapas en el cerebro en desarrollo, Pax6 y Pax7 se expresaron en las diferentes áreas del prosencéfalo, el mesencéfalo y el mesencéfalo, lo que sugiere su participación en la diferenciación de las neuronas en partes específicas del cerebro en desarrollo.

Chronology Of Nephrogenic Events In Staged Aborted Human Embryos And Fetuses

Introduction: The description given in various textbooks and literature on development of nephrons in humankidney doesn’t include details of chronology of nephrogenic events at various fetal ages. Though several studieswere reported the knowledge on development of kidney especially on the nephrogenesis are limited. The studiesemphasize the relationship between prenatal development of kidney and adult onset of renal diseases. Hence, anattempt was made in this study to obtain information by observing the serial sections of kidney of embryos andfoetuses of different gestational ages for better understanding of nephrogenic events.Material and methods: Thirty-five aborted embryos and dead fetuses of 5 weeks gestational age to full term wereutilized for this study. The specimens were subjected to routine tissue processing and haematoxylin and eosin(H&E) staining. 5 embryos of less than 8 weeks gestational age were processed as a whole and were seriallysectioned. The histological sections of 5 microns thickness were observed for the time of appearance of variousnephrogenic components and photographed.Results: Differentiating pronephric, mesonephric and metanephric components in different weeks i.e. 05 – 12, 13– 24, 25-36 were studied. In 06 – 12 weeks group a delay in the appearance of Pro and mesonephric, Meso andmetanephric ducts were observed that appeared during the 6th week. Differentiation of other components havenot completed by 6th week when compared with literature. In 13 – 24 weeks also there is delay in corticomedullary differentiation that was observed at 16 wks. at which time the morphologically recognizable Nephronswere also observed. Major part of development occurred between 16-28 weeks instead of 16-24weeks as statedin the literature. Ampulla division continued beyond 24 weeks. Increased number of mature nephrons wereobserved between 24-28 weeks instead of 16-20 wks., nephron arcades were observed during 24-28 weeksinstead of 14-22weeks.Conclusion: Detailed findings of this study could aid the embryologists, neonatologists and nephrologists tounderstand the chronology of nephrogenic events and related consequences of developmental abnormalities.

Ethical problems with the preimplantation genetic diagnosis of human embryos / Problemas éticos con el diagnóstico genético preimplantacional de embriones humanos / Problemas éticos com diagnóstico pré-implantacional de embriões humanos

Abstract: 14. The purpose of preimplantation genetic diagnosis by embryonary biopsy is to identify genetic alterations prior to the implantation of embryos produced by in vitro fertilization. The most important aim is the selection of genetically healthy embryos due to their genetic indemnity, but it can also be used to select the sex or, eventually, other detectable traits accrding to the wishes of the parents. This procedure has been the subject of scientific debates, in relation to the harm that it can cause to healthy embryos that are going to be implanted, and in relation to the interpretation of the genetic tests made. Ethical debates have also focused on the production of and respect for the life and the integrity of developing human beings. In this work, it is argued that most of the uses of PGD are morally reprehensible, because they are done with disregard to the dignity that should be granted to embryos as human persons.

Resumen: 18. El diagnóstico genético preimplantacional (DGP) mediante biopsia embrionaria tiene como objeto la detección de alteraciones genéticas previamente a la implantación de embriones producidos por fertilización in vitro (FIV). Su finalidad más significativa es la selección de embriones por su indemnidad genética. También se puede emplear para seleccionar el sexo o eventualmente otras características detectadas según el deseo de los padres. Este procedimiento ha sido objeto de debates en el ámbito científico, por el eventual daño que puede ocasionar la técnica en embriones sanos que serán implantados y por las interpretaciones de los exámenes genéticos realizados. También ha sido objeto de debates en el ámbito ético-antropológico, en cuanto a la producción y al respeto a la vida e integridad de los seres humanos en desarrollo. En este trabajo se argumenta que los usos que se hacen del DGP son, en su gran mayoría, moralmente reprochables, por hacerse con desprecio de la dignidad que debe darse al embrión como persona humana.

Resumo: 22. O Diagnóstico genético pré-implantacional (PGD) por meio de biópsia embrionária visa a identificação de alterações genéticas prévias à implantação de embriões produzidos por fertilização in vitro (FIV). Seu propósito mais significativo é a seleção de embriões por sua característica genética. Ele também pode ser usado para selecionar o sexo ou, eventualmente, outras características identificadas de acordo com os desejos dos pais. Este procedimento tem sido tema de debate em âmbito científico, por eventual dano que pode ocaciosionar a técnica em embriões saudáveis que serão implantados e pela interpretações dos exames genéricos realizados. Ele também tem sido objeto de debate na área ético-antropológica, no que concerne a produção e o respeito à vida e integridade do ser humano em desenvolvimento. Este artigo argumenta que os usos que são feitos do PGD são, em sua grande maioria, moralmente condenáveis, por ser instrumentalizado com desrespeito pela dignidade que deve ser dada ao embrião como uma pessoa humana.

Persistent right umbilical vein: a study using serial sections of human embryos and fetuses / 대한해부학회지

Persistent right umbilical vein (PRUV) is a common anomaly of the venous system. Although candidates for future PRUV were expected to occur more frequently in earlier specimens, evaluation of serial horizontal sections from 58 embryos and fetuses of gestational age 5–7 weeks found that only two of these embryos and fetuses were candidates for anomalies. In a specimen, a degenerating right umbilical vein (UV) joined the thick left UV in a narrow peritoneal space between the liver and abdominal cavity, and in the other specimen, a degenerating left UV joined a thick right UV in the abdominal wall near the liver. In these two specimens, the UV drained into the normal, umbilical portion of the left liver. These results strongly suggested that, other than the usual PRUV draining into the right liver, another type of PRUV was likely to consist of the right UV draining into the left liver.

CRISPR/Cas9 y la terapia génica / CRISPR/Cas9 and gene therapy

El desarrollo de técnicas que permitan editar o corregir con precisión y eficiencia el genoma de células vivas es uno de los objetivos principales de la investigación biomédica. En las últimas décadas se han investigado e implementado distintas herramientas de edición genómica entre las cuales se destaca el sistema CRISPR/Cas9, un mecanismo de defensa bacteriano que ha sido adaptado y rediseñado para su utilización en otros modelos celulares. La accesibilidad, técnica y económica, y el enorme potencial de CRISPR/Cas9 han dado lugar a una revolución casi sin precedentes en las ciencias biomédicas y representan un gran avance en el campo de la terapia génica que requiere, sin embargo, la cautela apropiada.

The development of techniques that allow the precise and efficient edition of the genome of living cells is one of the main goals of biomedical research. Over the last few decades, a number of genome editing tools have been developed, the most prominent being the CRISPR/Cas9 system, a bacterial defense mechanism that has been redesigned for its use in other cellular systems. The accessibility, both technical and economical, and the enormous potential of CRISPR/Cas9 have contributed to an almost unprecedented revolution in the biomedical sciences and represent an important step forward in the field of gene therapy that needs, however, to be taken cautiously.

Moral assessment of frozen human embryo adoption in the light of the Magisterium of the Catholic Church / Evaluación moral de la adopción de embriones humanos congelados a la luz del Magisterio de la Iglesia Católica / Avaliação moral de adoção de embriões humanos congelados, em consideração ao Magistério da Igreja Católica

As the number of frozen human embryos continues to rise daily, with numbers not expected to fall, an answer must be found to this dilemma. Four possible solutions have been suggested: a) thaw the embryos and allow them to perish; b) thaw them and donate them for biomedical research; c) thaw them and donate them in adoption; and d) leave them frozen indefinitely. This paper will evaluate the morality of these four possible solutions, particularly frozen human embryo adoption in the light of the Magisterium of the Catholic Church, which in its Instruction Dignitas Personae, appears to have opted to consider this practice as illicit. We also review the various stances of expert moralists in favour of or against frozen human embryo adoption, and we reflect on the extent to which the doctrine contained in Dignitas Personae can bind the moral conscience of the Catholic faithful. Finally, we make a personal evaluation of frozen human embryo adoption, in an attempt to find moral reasons that substantiate the negative opinion manifested by the Catholic Magisterium on this matter. In conclusion, we suggest that the moral assessment of frozen human embryo adoption as set forth in Dignitas Personae might not be considered as settled. Therefore, we are of the opinion that there is no impediment to further research on the moral foundation of this adoptive practice; however, insofar as this occurs, we believe that the best attitude of the Catholic faithful is to follow the moral criteria presented in Dignitas Personae with respect to the adoption of frozen human embryos.

Cada día aumenta el número de embriones humanos congelados y no se prevé que su número disminuya, por lo que parece necesario buscar una solución a este problema. Se han planteado cuatro posibles: a) descongelarlos y dejarlos morir; b) descongelarlos y donarlos para investigaciones biomédicas; c) descongelarlos y donarlos en adopción; y d) dejarlos congelados indefinidamente. En este trabajo se evalúa la moralidad de estas cuatro posibles soluciones, y espacialmente de la adopción de los embriones humanos congelados a la luz del Magisterio de la Iglesia Católica, que en su Instrucción Dignitas Personae, se decanta por la ilicitud de dicha práctica. También se revisan distintas posturas de moralistas expertos favorables o no a la adopción de embriones humanos congelados. Igualmente se reflexiona sobre en qué medida la doctrina contenida en Dignitas Personae puede obligar a la conciencia moral de los fieles católicos. Finalmente se realiza una evaluación personal de la adopción de embriones humanos congelados tratando de buscar razones morales que fundamenten el porqué del juicio negativo manifestado por el Magisterio Católico. Los autores sostienen que la ilicitud ética de la adopción de embriones humanos congelados puede radicar en la ilicitud moral de la subrogación, que hace ilícito todo el proceso procreativo, constituido por: acto conyugal, fecundación del óvulo e implantación del embrión producido en el útero en su madre biológica. Finalmente se plantea que lo expuesto en Dignitas Personae posiblemente no da por zanjada la valoración moral de la adopción de embriones humanos congelados, por lo que somos de la opinión de que no existe impedimento alguno para poder seguir investigando sobre la fundamentación moral de esta práctica adoptiva; pero que, en tanto en cuanto ello se produzca, nos parece que la mejor actitud de los fieles católicos es seguir los criterios morales de Dignitas Personae, expone con respecto a la adopción de embriones humanos congelados.

Cada dia aumenta o número de embriões humanos congelados e não se espera o número diminua, portanto parece necessário encontrar uma solução para este problema. Foram levantadas quatro possíveis: a) descongelá-los e deixá-los morrer; (b) descongelá-los e doá-los para pesquisa biomédica; (c) descongelada-los e doá-los para adoção; e (d) deixá-los congelados indefinidamente. Nesse trabalho se avalia a moralidade dessas quatro possíveis soluções e especialmente a adoção de embriões humanos congelados à luz do Magistério da Igreja Católica, que em sua instrução Dignitas Personae, opta pela ilegalidade da prática. Também se revisam posturas diferentes dos moralistas especialistas favoráveis ou não à adoção de embriões humanos congelados. Igualmente, reflete-se sobre como a doutrina contida na Dignitas Personae pode obrigar a consciência moral dos fiéis católicos.Finalmente se realiza uma avaliação pessoal da adoção de embriões humanos congelados pretendendo buscar razões morais que fundamentem o porquê do juízo negativo manifestado pelo magistério católico. Os autores argumentam que a ilegalidade ética da adoção de embriões humanos congelados pode resultar na ilicitude moral de sub-rogação, tornando ilícito todo o processoprocriador, constiuído por: ato conjugal, fertilização do óvulo e implantação do embrião produzido no útero de sua mãe biológica. Finalmente, apresenta-se que o exposto no Dignitas Personae, possivelmente, não dá por resolvida a valoração moral da adopção de embriões humanos congelados, portanto somos da opinião de que não há nenhum impedimento para seguir pesquisando sobre o fundamentação moral desta prática adotiva; Porém, porquanto ele se produza, parece-nos que a melhor atitude dos fiéis católicos será seguir os critérios morais de Dignitas Personae, expostos no que se refere a adoção de embriões humanos congelados.

Valoración de la adopción de embriones humanos congelados desde el punto de vista de la filosofía moral, la ética laica y dos religiones monoteístas / Valuating frozen human embryo adoption from a moral philosophical point of view, lay ethics and two monotheist religions / Valoração da adoção de embriões humanos congelados do ponto de vista da filosofia moral, a ética laica e duas religiões monoteístas

La búsqueda de la eficacia en la fecundación in vitro hace que se produzcan más embriones que los que se implantarán, lo que produce un excedente de embriones, que es congelado. Esto hace que ineludiblemente el número de embriones humanos congelados aumente. Entre las soluciones para dichos embriones humanos congelados está la donación/adopción de los mismos. Ineludiblemente esta práctica conlleva objetivos problemas éticos. En este trabajo se evalúa la eticidad de la donación/adopción de embriones humanos congelados desde la perspectiva de la filosofía moral, lo que podríamos llamar una "ética laica" y dos de las religiones monoteístas: la musulmana y la judía.

The search for IVF efficacy leads to a higher embryo production than it is necessary for implantation; this results in an excess of embryos which are kept frozen. This amount of frozen embryos inevitably increases. The donation/adoption are among the possible solutions for these frozen embryos. However, this practice has objective ethical problems. This article considers the ethical aspects of the donation / adoption of frozen human embryos from the point of view of moral philosophy, from what we could call "secular ethics" and from two monotheistic religions: Muslim and Jewish.

A busca da eficácia na fecundação in vitro faz com que se produzam mais embriões dos que se implantarão, o que produz um excedente de embriões, que é congelado. Isto faz com que inquestionavelmente o número de embriões humanos congelados aumente. Entre as soluções para os ditos embriões humanos congelados está na doação/adoção dos mesmos. Ineludivelmente esta prática implica objetivos problemas éticos. Neste trabalho se avalia a eticidade da doação/adoção de embriões humanos congelados a partir da perspectiva da filosofia moral, o que poderíamos chamar uma "ética laica" e duas religiões monoteistas: a mulçumana e a judia.

Perineal raphe with special reference to its extension to the anus: a histological study using human fetuses / 대한해부학회지

The raphe of the human penis and scrotum is considered to develop secondarily after disappearance of the initial midline seam by fusion of the bilateral genital folds. However, the fetal development was still obscure. We examined histological sections of 30 fetuses (17 males and 13 females) at 10-15 weeks. In male fetuses, the scrotum was not yet clearly identified because of no descent of testis. The perineal raphe was thin and wavy at 10 weeks, and it was continuous with and took a direction same as the inferior wall of the closed penile urethra after physiological hypospadias. Depending on growth of the bulbospongiosus muscle and corpus spongiosus penis, the midline intermuscular septum obtained a connection to the subcutaneous wavy raphe and made the latter thick and straight at 12-15 weeks. Notably, the perineal raphe extended posteriorly to attach to the external anal sphincter. In female fetuses, an epithelial fusion occurred along a short distance at the posterior end of the vestibule. However, in front of the external anal sphincter, a large midline mesenchymal tissue from the urorectal septum did not contain a raphe-like structure. Moreover, since the bilateral bulbospongiosus muscles were separated widely by the vestibule, they did not provide a midline septum. Fetal development of the perineal raphe was accelerated by reinforcement from the muscular septum. In contrast, without such a muscular support, the female raphe could not maintain its growth even if the seed appeared at the posterior end of the vestibule.

Tongue Growth during Prenatal Development in Korean Fetuses and Embryos

BACKGROUND: Prenatal tongue development may affect oral-craniofacial structures, but this muscular organ has rarely been investigated. METHODS: In order to document the physiology of prenatal tongue growth, we histologically examined the facial and cranial base structures of 56 embryos and 106 fetuses. RESULTS: In Streeter's stages 13-14 (fertilization age [FA], 28 to 32 days), the tongue protruded into the stomodeal cavity from the retrohyoid space to the cartilaginous mesenchyme of the primitive cranial base, and in Streeter's stage 15 (FA, 33 to 36 days), the tongue rapidly swelled and compressed the cranial base to initiate spheno-occipital synchondrosis and continued to swell laterally to occupy most of the stomodeal cavity in Streeter's stage 16-17 (FA, 37 to 43 days). In Streeter's stage 18-20 (FA, 44 to 51 days), the tongue was vertically positioned and filled the posterior nasopharyngeal space. As the growth of the mandible and maxilla advanced, the tongue was pulled down and protruded anteriorly to form the linguomandibular complex. Angulation between the anterior cranial base (ACB) and the posterior cranial base (PCB) was formed by the emerging tongue at FA 4 weeks and became constant at approximately 124degrees-126degrees from FA 6 weeks until birth, which was consistent with angulations measured on adult cephalograms. CONCLUSIONS: The early clockwise growth of the ACB to the maxillary plane became harmonious with the counter-clockwise growth of the PCB to the tongue axis during the early prenatal period. These observations suggest that human embryonic tongue growth affects ACB and PCB angulation, stimulates maxillary growth, and induces mandibular movement to achieve the essential functions of oral and maxillofacial structures.

Sourcing human embryos for embryonic stem cell lines: Problems & perspectives.

The ability to successfully derive human embryonic stem cells (hESC) lines from human embryos following in vitro fertilization (IVF) opened up a plethora of potential applications of this technique. These cell lines could have been successfully used to increase our understanding of human developmental biology, transplantation medicine and the emerging science of regenerative medicine. The main source for human embryos has been ‘discarded’ or ‘spare’ fresh or frozen human embryos following IVF. It is a common practice to stimulate the ovaries of women undergoing any of the assisted reproductive technologies (ART) and retrieve multiple oocytes which subsequently lead to multiple embryos. Of these, only two or maximum of three embryos are transferred while the rest are cryopreserved as per the decision of the couple. in case a couple does not desire to ‘cryopreserve’ their embryos then all the embryos remaining following embryo transfer can be considered ‘spare’ or if a couple is no longer in need of the ‘cryopreserved’ embryos then these also can be considered as ‘spare’. But, the question raised by the ethicists is, “what about ‘slightly’ over-stimulating a woman to get a few extra eggs and embryos? The decision becomes more difficult when it comes to ‘discarded’ embryos. As of today, the quality of the embryos is primarily assessed based on morphology and the rate of development mainly judged by single point assessment. Despite many criteria described in the literature, the quality assessment is purely subjective. The question that arises is on the decision of ‘discarding’ embryos. What would be the criteria for discarding embryos and the potential ‘use’ of ESC derived from the ‘abnormal appearing’ embryos? This paper discusses some of the newer methods to procure embryos for the derivation of embryonic stem cell lines which will respect the ethical concerns but still provide the source material.

Consideracionesbbiológicas y antropológicas acerca del embrión y la reproducción asistida / Biological and anthropological considerations about embryo and assisted reproduction

Se analizan los criterios que desde la biología y la antropología filosófica permiten afirmar que desde la formación del cigoto, resultado de la singamia de gametos humanos, nos encontramos frente a un ser humano, a una persona humana en acto que expresa su existencia de acuerdo con su circunstancia. Se aclaran desde la antropología filosófica las objeciones que algunos presentan a la concepción de la persona humana. Toda manipulación del embrión humano, aunque sea con fines aparentemente humanitarios, merece un radical rechazo ético, a menos que dicha manipulación redunde directamente en su bien personal e individual.

This article analyzes criteria that, in the light of biology and philosophical anthropology, allow us to affirm that from the very formation of the zygote, i.e., the result of human gamete syn-gamy, we actually are in the presence of a human being, a human individual in an act expressing its (his or her) existence according to its (his or her) own circumstance. From philosophical anthropology, certain objections relating to the human being conception are clarified. Any manipulation of the human embryo, even for apparently humanitarian purposes, deserves drastic ethical rejection, unless any such manipulation directly redounds to its own personal and individual good.

Este texto analisa os critérios biológicos e antropológico-filosóficos que permitem afirmar que o zigoto resultante da singamia de gâmetas humanos é um ser humano, uma pessoa humana em ato que manifesta sua existência segundo suas circunstâncias. Desde a perspectiva da antropologia filosófica, são contra-restadas as críticas de alguns à conceição da pessoa humana. Deve ser rejeitada toda manipulação do embrião humano desde uma perspectiva ética, mesmo com fines na aparência humanitários, salvo que seja para benefício pessoal ou individual.

Effect of Ethylene Glycol (EG) and 1,2-Propanediol (PROH) on the Survival and the Development of Mouse and Human Embryosafter Slow Freezing/Rapid Thawing Protocol / 대한불임학회지

OBJECTIVE: The aim of this study were to compare the effects of EG and PROH on cryopreservation of mouse and human embryos, and to find the optimal protocol for embryo freezing. METHODS: Human embryos derived from fertilized eggs showing 3 pronuclei (PN) and mouse embryos were divided into two groups respectively: dehydrated with 1.5 M EG+0.2 M sucrose or 1.5 M PROH+0.2 M sucrose using the slow freezing method. Moreover mouse embryos were controlled the exposure time of cryoprotectant during dehydration or rehydration steps. RESULTS: The survival rates of human embryos were 79.2% (84/106) in EG group and 77.9% (88/113) in PROH group. In mouse embryos, the survival and development rates up to blastocyst were 70.6% (245/347), 44.1% (123/279) in EG group and 62.1% (198/319), 45.1% (123/279) in PROH group, respectively. However, in EG group, partially damaged embryos after thawing were decreased compared to PROH group. In combination group, when the exposure time during dehydration and rehydration were reduced, the survival and embryonic developments were increased slightly, but not significant. CONCLUSION: Cryopreservation of mouse and human embryos at cleavage stage by using EG or PROH exhibited no statistical difference in the survival rate and/or developmental rate to blastocyst. However, the use of EG for cryopreservation of embryos might reduce the exposure time of the cryoprotectant because of a high permeation of EG and result in lessen its toxic effects.

Effects of Different Infusion Frequency of Liquid Nitrogen on Human Embryo Development and Pregnancy Rates after Freezing and Thawing / 대한불임학회지

OBJETIVE: To investigate the efficacy of high infusion frequency of liquid nitrogen on pregnancy in human embryo after freezing and thawing. MATERIALS AND METHODS:: 150 infertile patients underwent 162 consecutive thawing-ET cycles. In the high infusion frequency group (Group A), 47 patients (50 cycles) underwent cryopreservation with high infusion frequency of liquid nitrogen. In the low infusion frequency group (Group B), 103 patients (112 cycles) underwent cryopreservation with low infusion frequency of liquid nitrogen. We analyzed the clinical characteristics, fertilization rates, development of embryo, good quality embryo ratio, implantation rates, and pregnancy rates between these two groups. RESULTS: There was no difference between the groups with regard to clinical characteristics (mean age, infertility duration, infertility factors, hormone profile), mean number of oocyte retrieval, fertilization rates, and mean embryo number of transfers. The survival rates in group A was 64.9% (228 of 350 embryos), and among the 228 embryos 190 embryos (83.3%) which progressed to the two- to eight-cell stage. After thawing, the embryo numbers were 65 (34.2%), 29 (15.3%), 35 (18.4%), and 37 (19.5%) of grades 1, 2, 3, and above 4, respectively. The survival rates in group B was 63.8% (482 of 755 embryos), and among the 482 embryos 465 embryos (96.5%) which progressed to the two- to eight-cell stage. After thawing, the embryo numbers were 106 (22.8%), 94 (20.2%), 89 (19.1%), and 112 (24.1%) of grades 1, 2, 3, and above 4, respectively. There was no difference in embryo quality change after the freezing-thawing procedure between the groups. Implantation rates (31.1% vs. 34.3%) were not significant. However hCG positive rates in group A (40%) were higher than group B, but not statistically significant. Clinical pregnancy rate (26% vs. 25.9%), on going pregnancy rates (>20 weeks) were not significant (26% vs. 25%). CONCLUSION: We compared embryo quality change, survival rates, and pregnancy rates between high infusion frequency group and low infusion frequency group and the results were similar between the two groups. Therefore, high infusion frequency of liquid nitrogen for cryopreservation is a worthy method to preserve in human embryos.

A study on chondrogenic potential in mandibular and limb bud mesenchymal cells of human embryos : A possible role of protein kinase C / 대한치과교정학회지

We have examined the in vitro stage-related chondrogenic potential of human mandibular and limb bud mesenchyme cells using micromass culture, Our results indicate that limb bud mesenchyme cells as early as stage 16 by Carnegie system (37 days), well before the initiation of in vivo chondrogenesis, have chondrogenic potential which is expressed in micromass culture, These results are correlated with stage-related chondrogenic potential of human limb bud in vivo as a result of Alcian blue staining. The proliferation of chondrogenic cells increased in the first 3 days after culture and then decreased. These results were correlated with the cell cycle analysis of which the number of G degrees/G1 phase increased markedly after 3 days of culture, while the percentage of cells in S phase was decreased, On the other hand, it was rarely differentiated in the mandible. We examined the effects of two PKC modulators such as phorbol 12-myristate 13-acetate (PMA), a potent activator of PKC, and staurosporine (STSN), an inhibitor of PKC. PMA inhibited the chondrogenesis, whereas STSN promoted the chondrogenesis in a dose dependent manner. In addition, PMA exerted no inhibitory effect when the cells were pretreated for 24 h with STSN, implying that the chondrogenic events might be settled at an early step in vitro and PKC may act as a negative modulator, Collectively, these results demonstrate, for the first time, the stage-related chondrogenic potential of human mandibular and limb bud mesenchyme cells and the role of PKC during chondrogenesis in vitro & in vivo.

HISTOGENESIS OF THE HUMAN STOMACH / 解剖学报

In this article we collected 2 embryos and 69 fetuses between 7 and 30 weeks of gestational age and 3 neonates to study the development of the human stomach by histological, histochemical and immunogold-siver methods. In 7-week embryo, the superficial layer of gastric mucosa was stratified columnar epithelium, containing a large amount of glycogen. In 9-week fetus, simple columnar epithelium, gastric pits and glandular buds were observed. At this stage a few parietal cells could be identified at the bottom of the glands. The pyloric glands contained parietal cells as fundic glands. At 13-14 week the muscularis mucosa appeared and the wall of stomach formed definitively as the adult. A few argyrophil cells in antrum and fundus were found at 12-week fetus. They scattered in the surface epithelium and concentrated in the lower portion of the glands. The argyrophil cells were round, pyramidal or spindle in shape. More argyrophil ceils were found in the antrum from 14-week on. At 18-week, the argyrophil cells were most numerous. Some cells possessed processes extending to the basement membrane or parietal cells. Between 15-30 weeks various shaped EC cells in fundus were found, with some open-type endocrine cells. G cells in antrum were mostly rounded and often in groups at 13,16 and 21 week. Developing G cells were observed under EM.