Category Archives: Human Reproduction

http://www.centerforhumanreprod.com Is Egg Donation right for you? Norbert Gleicher MD from Center for Human Reproduction in New York, NY explains the egg donation or oocyte donation process and provides valuable insight into when egg donation is appropriate.

Here is the original post:
Egg Donation/ Donor Egg Program - Video

What is a Man? What is a Woman?

Originally posted here:
Journey Of A Pregnant Man - Thomas Beatie (1 of 5) - Video

BACKGROUND

In IVF treatment a considerable proportion of women are faced with a low number of oocytes retrieved. These poor responders have reduced pregnancy rates compared with normal responders. However, this may not be applicable to all poor responders. This review aims at identifying patient characteristics and ovarian reserve tests (ORT) that will determine prognosis for pregnancy in poor responders.

METHODS

A systematic search was conducted in PubMed, Embase, Cochrane and SCOPUS databases in April 2010. Studies regarding patient characteristics or ORT in poor responders and their pregnancy prospects were included. All included papers were summarized in descriptive tables.

RESULTS

Nineteen studies were included. Pooled data of six studies comparing poor and normal responders demonstrated clearly lower pregnancy rates in poor responders (14.8 versus 34.5%). Ten studies indicated that older poor responders have a lower range of pregnancy rates compared with younger (1.5–12.7 versus 13.0–35%, respectively). Four studies showed that pregnancy prospects become reduced when fewer oocytes are retrieved (0–7% with 1 oocyte versus 11.5–18.6% with 4 oocytes). Five studies concerning pregnancy rates in subsequent cycles suggested a more favourable outcome in unexpected poor responders, and if ≥2 oocytes were retrieved.

CONCLUSIONS

Poor responders are not a homogeneous group of women with regards to pregnancy prospects. Female age and number of oocytes retrieved in particular will modulate the chances for pregnancy in current and subsequent cycles. Applying these criteria will allow the identification of couples with a reasonable prognosis and balanced decision-making on the management of poor responders.

Source:
http://humupd.oxfordjournals.org/rss/current.xml

BACKGROUND

Ovarian follicles undergo dynamic morphologic and endocrinologic changes during the human menstrual cycle. The physiologic mechanisms underlying recruitment and selection of antral follicles in women are not fully elucidated.

METHODS

A comprehensive review of >200 studies was conducted using PubMed. The objective was to compare and contrast different perspectives on human antral folliculogenesis.

RESULTS

Antral folliculogenesis has been studied using histologic, endocrinologic and/or ultrasonographic techniques. Different theories of antral follicle recruitment include: (i) continuous recruitment throughout the menstrual cycle; (ii) recruitment of a ‘cohort’ of antral follicles once in the late-luteal phase or early-follicular phase of each cycle and (iii) recruitment of two or three ‘cohorts’ or ‘waves’  during each cycle. Generally, a single dominant follicle is selected in the mid-follicular phase of each cycle and this follicle ovulates at mid-cycle. However, a dominant follicle may also be selected during anovulatory waves that precede the ovulatory wave in some women.

CONCLUSIONS

There is increasing evidence to indicate that multiple waves of antral follicles develop during the human menstrual cycle. Ovarian follicular waves in women are comparable with those documented in several animal species; however, species-specific differences exist. Enhancing our understanding of the endocrine and paracrine mechanisms underlying antral follicular wave dynamics has clinical implications for understanding age-related changes in reproductive function, optimizing hormonal contraceptive and ovarian stimulation regimens and identifying non-invasive markers of the physiologic status of follicles which are predictive of oocyte competence and assisted reproduction outcomes.

Source:
http://humupd.oxfordjournals.org/rss/current.xml

BACKGROUND

Meiosis is a unique form of cell division in which cells divide twice but DNA is duplicated only once. Errors in chromosome segregation during meiosis will result in aneuploidy, followed by loss of the conceptus during pregnancy or birth defects. During mitosis, cells utilize a mechanism called the spindle assembly checkpoint (SAC) to ensure faithful chromosome segregation. A similar mechanism has been uncovered for meiosis in the last decade, especially in the past several years.

METHODS

For this review, we included data and relevant information obtained through a PubMed database search for all articles published in English from 1991 through 2011 which included the term ‘meiosis’, ‘spindle assembly checkpoint’, or ‘SAC’.

RESULTS

There are 91 studies included. Evidence for the existence of SAC functions in meiosis is provided by studies on the SAC proteins mitotic-arrest deficient-1 (Mad1), Mad2, budding uninhibited by benzimidazole-1 (Bub1), Bub3, BubR1 and Mps1; microtubule-kinetochore attachment regulators Ndc80 complex, chromosomal passenger complex, mitotic centromere-associated kinesin (MCAK), kinetochore null 1 (KNL1) and Mis12 complex and spindle stability regulators.

CONCLUSIONS

SAC and its regulators exist and function in meiosis, and their malfunctions may cause germ cell aneuploidy. However, species and sexual differences exist. Moreover, interaction of SAC components with other regulators is still poorly understood, which needs further study.

Source:
http://humupd.oxfordjournals.org/rss/current.xml

BACKGROUND

Achieving the correct spatial and temporal expression of germ-cell-specific genes is fundamental to the production of viable healthy spermatozoa. Notably, post-transcriptional gene regulation resulting in the repression of protein translation is central to many embryonic processes, and is particularly active during spermatogenesis. In this review, we discuss microRNA (miRNA) regulation of target gene expression in relation to mammalian spermatogenesis, the establishment of testicular germ cell tumours (TGCT) and the potential use of miRNA manipulation for cancer therapy and fertility regulation.

METHODS

Journal databases such as PubMed were searched using key words, including miRNA, testis, spermatogenesis, germ cell, testicular cancer and cancer.

RESULTS

In the past decade, the deployment of small non-coding RNA molecules, including miRNA, by the cell, has been recognized as among the most important mechanisms of fine-tuning translational regulation in differentiating cell types. For key regulators of male gametogenesis, high levels of gene expression do not always correspond to elevated levels of protein expression. Cumulatively this indicates that enhancement and repression of post-transcriptional regulatory mechanisms are essential to the success of spermatogenesis. There is also growing evidence that this form of regulation contributes to the aetiology of both TGCT and spermatocytic tumours.

CONCLUSIONS

miRNA plays an essential role in regulation of genes during the process of spermatogenesis. Disruption of this regulation has the ability to contribute to the neoplastic development of germ cell tumours. However, targeted knockdown of specific miRNA molecules has the potential to form both anti-oncogenic reagents and underpin the basis for novel contraceptive technologies.

Source:
http://humupd.oxfordjournals.org/rss/current.xml