Preimplantation Genetic Diagnosis:

Miniaturization of molecular biological techniques for gene assay

The rapid diagnosis of various diseases is a critical advantage of many emerging biomedical tools. Due to advances in preventive medicine, tools for the accurate analysis of genetic mutation and associated hereditary diseases have attracted significant interests in recent years. The entire diagnostic process usually involves two critical steps, namely, sample pre-treatment and genetic analysis. The sample pre-treatment processes such as extraction and purification of the target nucleic acids prior to genetic analysis are essential in molecular diagnostics. The genetic analysis process may require specialized apparatus for nucleic acid amplification, sequencing and detection. Traditionally, pre-treatment of clinical biological samples (e.g. the extraction of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA)) and the analysis of genetic polymorphisms associated with genetic diseases are typically a lengthy and costly process. These labor-intensive and time-consuming processes usually result in a high-cost per diagnosis and hinder their practical applications. Besides, the accuracy of the diagnosis may be affected owing to potential contamination from manual processing. Alternatively, due to significant advances in micro-electro-mechanical-systems (MEMS) and microfluidic technology, there are numerous miniature systems employed in biomedical applications, especially for the rapid diagnosis of genetic diseases. A number of advantages including automation, compactness, disposability, portability, lower cost, shorter diagnosis time, lower sample and reagent consumption, and lower power consumption can be realized by using these microfluidic-based platforms. As a result, microfluidic-based systems are becoming promising platforms for genetic analysis, molecular biology and for the rapid detection of genetic diseases. In this review paper, microfluidic-based platforms capable of identifying genetic sequences and diagnosis of genetic mutations are surveyed and reviewed. Some critical issues with the use of microfluidic-based systems for diagnosis of genetic diseases are also highlighted.

Pregnancy and active Huntington disease: a rare combination

We describe the complicated course of a rare pregnant woman with symptomatic Huntington disease (HD) and discuss multidisciplinary care issues that may be encountered. A 31-year-old gravida 2, para 1 with advanced HD was admitted at 30 weeks gestation for preterm labor. Her course was complicated by progressive cognitive and physical impairment, dysphagia, malnutrition, diabetes insipidus, aspiration pneumonia, chorioamnionitis, preterm delivery and pyelonephritis. Pregnant women with symptomatic HD may present multiple challenges requiring extensive multidisciplinary input.

Jewish perspectives on the use of preimplantation genetic diagnosis

This article presents an analysis of the ethical considerations raised by preimplantation genetic diagnosis (PGD) from a Jewish perspective. It weighs the Jewish imperatives to pursue good health against a number of harms that may follow from the expanded use of PGD technology, including increased medical risk to the mother, the destruction of embryos and possible emotional harm to the child born from this procedure. It pays special attention to the potential harms that may befall those in society who do not have access to PGD or who choose not to employ it.

Identification and isolation of embryonic stem cells in reproductive endocrinology: theoretical protocols for conservation of human embryos derived from in vitro fertilization

BACKGROUND

Embryonic stem cells (ESC) are pluripotent cells obtained from the inner cell mass (ICM) of blastocysts derived from in vitro culture associated with reproductive endocrinology therapy. Human ESCs are regarded as highly significant since they retain the capacity to differentiate into any of approximately 200 unique cell types. Human ESC research is controversial because to acquire such cells, the ICM of human blastocysts must be manipulated in a way that renders embryos nonviable and unsuitable for transfer in utero. Techniques to yield competent ESCs with conservation of source blastocysts would satisfy many objections against ESC research, but at present such approaches remain largely untested.

RESULTS AND DISCUSSION

We contrast experimental culture of single blastomeres obtained by 1) non-destructive biopsy of embryos destined for transfer, and 2) isolation of karyotypically normal blastomeres from disaggregated ("dead") embryos considered unsuitable for transfer, and evaluate these approaches with regard to production of ESCs. Pluripotency was confirmed by morphological criteria and by quantification of divergent homeodomain proteins specific to undifferentiated cell development. Following ESC isolation and identification, assessment was conducted according to a novel ESC grading system, also proposed here.

CONCLUSION

The role of reproductive endocrinology in ESC research remains paramount. In this report, we hypothesize new and expand on existing strategies having the potential to enhance human ESC isolation, identification and in vitro maintenance.