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The question of cell renewal is one that all of us have intuitive daily experience with. We all notice that our hair falls out regularly, yet we don't get bald (at least not until males reach a certain age!).  Similarly, we have all had the experience of cutting ourselves only to see how new cells replaced their damaged predecessors. And we donate blood or give blood samples without gradually draining our circulatory system. All of these examples point to a replacement rate of cells, that is characteristic of different tissues and in different conditions, but which makes it abundantly clear that for many cell types renewal is a part of their story.

The Path to Myozyme Beginning in the 1960s and fueled by the biotechnology revolution in 1980s, researchers at academic centers around the world initiated work to identify a treatment for Pompe - including therapies that could replace the missing GAA enzyme in patients. Based on these early efforts, from 1998-2002 Genzyme worked to advance promising research involving four different drug candidates to treat Pompe:

LUMIZYME® (alglucosidase alfa) is an enzyme replacement therapy for patients with Pompe disease (acid α-glucosidase (GAA) deficiency).

In order to improve the surgical outcome of these procedures and enhance patient quality of life, new and better tools are needed for esophageal reconstruction. Biostage is working on a new regenerative technology to address esophageal cancer through their pioneer Cellframe Technology. Two weeks before the surgery, stem cells are harvested from patient abdominal adipose tissue and allowed to incubate with a biocompatible esophageal implant. These cells interact and adhere to the implant and are able to respond to signals for regeneration once inside the patient, potentially restoring both the structural and functional integrity of the esophagus. These new approaches to organ implants could revolutionize resectional surgery by providing patients with functional replacements derived from their own cells.

This interrupted case study examines molecular genetic evidence reported in scientific literature to determine the fate of Louis-Charles, son of Louis XVI and Marie-Antoinette of France. Controversy and rumors surrounding the death of Louis-Charles suggested that either he died as a young boy while being held in captivity by the French revolutionaries or he escaped and was replaced by a substitute who died in his place. One individual claiming to be Louis-Charles was Karl Naundorff. Students begin the case by preparing pedigrees for the descendants of Maria Theresa and Francis I, the Holy Roman Emperor, parents of Marie-Antoinette. The pedigrees can be used to introduce the concepts of alleles identical-by-descent and cytoplasmic inheritance patterns. Students then compare mitochondrial DNA sequences and XY chromosome sequences from hair, bone, heart, and blood samples taken from descendants of Marie Theresa, Karl Naundorff and the heart of the boy who died in captivity to determine if the latter was truly Louis-Charles. An optional PowerPoint presentation with clicker questions is available to help guide the classroom activities.

Possibly the most exciting use of stem cells rests on their ability to differentiate into an enormous range of healthy functioning adult cells, thereby providing a replacement source of cells to treat serious diseases. This ultimately means that virtually any disease that results in cellular and tissue destruction can potentially be treated by stem cells. Some of the conditions are particularly debilitating and these include diabetes, spinal cord injuries, retinal disease, Parkinson's disease, heart disease and cancer.

Chinese scientists say they've genetically modified human embryos for the very first time. The team attempted to modify the gene responsible for beta-thalassaemia, a potentially fatal blood disorder, using a gene-editing technique known as CRISPR/Cas9. Gene editing is a recently developed type of genetic engineering in which DNA is inserted, replaced, or removed. Here, experts weigh-in with ethical questions and considerations.

In the study, published Monday (May 1) in Nature Biotechnology,  Luo and colleagues set their sights on two fusions genes they had previously found to be associated with prostate cancer and various forms of rapid and invasive cancer, including liver tumors. Using a modified CRISPR-Cas9 tool that creates a single- rather than double-stranded break in DNA, they targeted the chromosomal breakpoints that form these fusion genes and replaced fusion DNA with a gene encoding the enzyme HSV1-tk. This enzyme effectively kills tumor cells by converting the drug ganciclovir into its active form, which then blocks DNA synthesis and leads to cell death. (Ganciclovir is used to treat cytomegalovirus in humans.)

For the first time, biologists have succeeded in growing human stem cells in pig embryos, shifting from science fiction to the realm of the possible the idea of developing human organs in animals for later transplant.