Julio Tudela

Does levonorgestrel emergency contraceptive have a post-fertilization effect? A review of its mechanism of action

Background: Recent studies have identified that levonorgestrel administered orally in emergency contraception (LNG-EC) is only efficacious when taken before ovulation. However, the drug does not consistently prevent follicular rupture or impair sperm function. Objective: The present systematic review is performed to analyze and more precisely define the extent to which pre-fertilization mechanisms of action may explain the drugs efficacy in pregnancy avoidance. We also examine the available evidence to determine if pre-ovulatory drug administration may be associated with post-fertilization effects. Conclusion: The mechanism of action of LNG-EC is reviewed. The drug has no ability to alter sperm function at doses used in vivo and has limited ability to suppress ovulation. Our analysis estimates that the drugs ovulatory inhibition potential could prevent less than 15 percent of potential conceptions, thus making a pre-fertilization mechanism of action significantly less likely than previously thought. Luteal effects (such as decreased progesterone, altered glycodelin levels, and shortened luteal phase) present in the literature may suggest a pre-ovulatory induced post-fertilization drug effect. Lay Summary: Plan B is the most widely used emergency contraceptive available. It is important for patients and physicians to clearly understand the drugs mechanism of action (MOA). The drug was originally thought to work by preventing fertilization. Recent research has cast doubt on this. Our review of the research suggests that it could act in a pre-fertilization capacity, and we estimate that it could prevent ovulation in only 15 percent or less of cases. The drug has no ability to alter sperm function and limited ability to suppress ovulation. Further, data suggest that when administered pre-ovulation, it may have a post-fertilization MOA.

Diez años desde el descubrimiento de las células iPS: estado actual de su aplicación clínica

On the 10-year anniversary of the discovery of induced pluripotent stem cells, we review the main results from their various fields of application, the obstacles encountered during experimentation and the potential applications in clinical practice. The efficacy of induced pluripotent cells in clinical experimentation can be equated to that of human embryonic stem cells; however, unlike stem cells, induced pluripotent cells do not involve the severe ethical difficulties entailed by the need to destroy human embryos to obtain them. The finding of these cells, which was in its day a true scientific milestone worthy of a Nobel Prize in Medicine, is currently enveloped by light and shadow: high hopes for regenerative medicine versus the, as of yet, poorly controlled risks of unpredictable reactions, both in the processes of dedifferentiation and subsequent differentiation to the cell strains employed for therapeutic or experimentation goals.

Analysis of the truth in advertising on the efficacy provided by assisted reproduction clinics

This paper analyses the efficacy data from assisted reproduction clinics, obtained from both scientific society reports and from studies published in specialised journals, in order to compare them with information published by Spanish assisted reproduction clinics on their websites. It aims to verify whether this information matches the reality of the findings in the media analysed or, in contrast, differs from the aforementioned scientific evidence. Our study shows marked discrepancies between the evidence of existing statistical data, and figures published by most of the clinics on their websites, which could constitute false advertising.

Ethical aspects of nuclear and mitochondrial DNA transfer

Somatic cell nuclear transfer (SCNT) (cloning), as a reproductive or therapeutic method, and mitochondrial DNA transfer, as a method to prevent the transmission of mitochondrial diseases, are analyzed in this paper from a bioethics perspective. The licit purpose of being able to treat certain diseases, as in the case of SCNT, cannot justify, in any case, resorting to illicit means such as the manipulation, selection, and elimination of human embryos in the blastocyst phase, by using cell lines obtained from them. Crossing this line paves the way (as utilitarian ethics advocates) to assuming any cost in scientific experimentation so long as satisfactory results are obtained. With mitochondrial replacement, either human embryos are directly manipulated (pronuclear transfer) or germline cells are manipulated (maternal spindle transfer); changes in these could be transmitted to the offspring. Lay Summary: This article analyzes somatic cell nuclear transfer (cloning) and mitochondrial DNA transfer techniques, in both reproductive and therapeutic applications, and preventive methods in the transmission of mitochondrial diseases, from a bioethical perspective. The manipulation, selection, and elimination of human embryos delimits the ethical acceptability of these promising techniques.

A FRAUDE NA PUBLICAÇÃO CIENTÍFICA: UMA POLÊMICA QUE NÃO CESSA

espanolEl fraude en la publicacion cientifica supone un lastre para la divulgacion de los trabajos de investigacion, cuyas causas conviene analizar. A la conducta reprobable de los investigadores que lo cometen puede sumarse el sesgo que las propias publicaciones cientificas y buscadores de Internet pueden introducir en los procesos de seleccion, validacion y calculo de los factores de impacto de los trabajos presentados y publicados. Este articulo ofrece una reflexion al respecto, a raiz de nuevos datos relacionados recientemente publicados. DOI: 10.5294/pebi.2014.18.2.5 EnglishFraud in scientific publishing is a drag on the release of research papers, the causes of which should be analyzed. To the reprehensible conduct of researchers who commit fraud one can add the bias the scientific publications and the Internet search engines can introduce to the processes of selection, validation, and calculation of the impact factors of papers already submitted and published. This article offers a reflection on the issue, as a result of related new data having recently been published. portuguesA fraude na publicacao cientifica supoe um obstaculo para a divulgacao dos trabalhos de pesquisa, cujas causas convem analisar. � conduta reprovavel dos pesquisados que o cometem, pode ser somado o inclinacao que as proprias publicacoes cientificas e buscadores de internet podem introduzir nos processos de selecao, validacao e calculo dos fatores de impacto dos trabalhos apresentados e publicados. Este artigo oferece uma reflexao a respeito disso, com base em novos dados relacionados recentemente publicados.Fraud in scientific publishing is a drag on the release of research papers, the causes of which should be analyzed. To the reprehensible conduct of researchers who commit fraud one can add the bias the scientific publications and the Internet search engines can introduce to the processes of selection, validation, and calculation of the impact factors of papers already submitted and published. This article offers a reflection on the issue, as a result of related new data having recently been published.

EL FRAUDE EN LA PUBLICACIÓN CIENTÍFICA: UNA POLÉMICA QUE NO CESA

espanolEl fraude en la publicacion cientifica supone un lastre para la divulgacion de los trabajos de investigacion, cuyas causas conviene analizar. A la conducta reprobable de los investigadores que lo cometen puede sumarse el sesgo que las propias publicaciones cientificas y buscadores de Internet pueden introducir en los procesos de seleccion, validacion y calculo de los factores de impacto de los trabajos presentados y publicados. Este articulo ofrece una reflexion al respecto, a raiz de nuevos datos relacionados recientemente publicados. DOI: 10.5294/pebi.2014.18.2.5 EnglishFraud in scientific publishing is a drag on the release of research papers, the causes of which should be analyzed. To the reprehensible conduct of researchers who commit fraud one can add the bias the scientific publications and the Internet search engines can introduce to the processes of selection, validation, and calculation of the impact factors of papers already submitted and published. This article offers a reflection on the issue, as a result of related new data having recently been published. portuguesA fraude na publicacao cientifica supoe um obstaculo para a divulgacao dos trabalhos de pesquisa, cujas causas convem analisar. � conduta reprovavel dos pesquisados que o cometem, pode ser somado o inclinacao que as proprias publicacoes cientificas e buscadores de internet podem introduzir nos processos de selecao, validacao e calculo dos fatores de impacto dos trabalhos apresentados e publicados. Este artigo oferece uma reflexao a respeito disso, com base em novos dados relacionados recentemente publicados.Fraud in scientific publishing is a drag on the release of research papers, the causes of which should be analyzed. To the reprehensible conduct of researchers who commit fraud one can add the bias the scientific publications and the Internet search engines can introduce to the processes of selection, validation, and calculation of the impact factors of papers already submitted and published. This article offers a reflection on the issue, as a result of related new data having recently been published.

FRAUD IN SCIENTIFIC PUBLISHING: A CONTROVERSY THAT DOES NOT CEASE

espanolEl fraude en la publicacion cientifica supone un lastre para la divulgacion de los trabajos de investigacion, cuyas causas conviene analizar. A la conducta reprobable de los investigadores que lo cometen puede sumarse el sesgo que las propias publicaciones cientificas y buscadores de Internet pueden introducir en los procesos de seleccion, validacion y calculo de los factores de impacto de los trabajos presentados y publicados. Este articulo ofrece una reflexion al respecto, a raiz de nuevos datos relacionados recientemente publicados. DOI: 10.5294/pebi.2014.18.2.5 EnglishFraud in scientific publishing is a drag on the release of research papers, the causes of which should be analyzed. To the reprehensible conduct of researchers who commit fraud one can add the bias the scientific publications and the Internet search engines can introduce to the processes of selection, validation, and calculation of the impact factors of papers already submitted and published. This article offers a reflection on the issue, as a result of related new data having recently been published. portuguesA fraude na publicacao cientifica supoe um obstaculo para a divulgacao dos trabalhos de pesquisa, cujas causas convem analisar. � conduta reprovavel dos pesquisados que o cometem, pode ser somado o inclinacao que as proprias publicacoes cientificas e buscadores de internet podem introduzir nos processos de selecao, validacao e calculo dos fatores de impacto dos trabalhos apresentados e publicados. Este artigo oferece uma reflexao a respeito disso, com base em novos dados relacionados recentemente publicados.Fraud in scientific publishing is a drag on the release of research papers, the causes of which should be analyzed. To the reprehensible conduct of researchers who commit fraud one can add the bias the scientific publications and the Internet search engines can introduce to the processes of selection, validation, and calculation of the impact factors of papers already submitted and published. This article offers a reflection on the issue, as a result of related new data having recently been published.