Category Archives: Gene Medicine

Gene medicine is making breakthroughs for health questions that have baffled humanity for centuries. Gene therapy is the applicable aspect of the science of gene medicine. Treatments are being developed that can reverse genetic diseases at the molecular level. Health questions that have previously be unanswered are now being solved. Health questions like how to remedy chronic pain are now being clinically tested and the gene therapy is already showing substantial subsiding of pain for the clinical trial patients. As countries put more funding into gene medicine, and more collaboration takes place between those countries, many of the health questions that we have today will be answered in the next decade

Gene medicine is one of the medical disciplines that affect all aspects of human health. From allergies, bone growth and cell development. Gene medicine is also one of the most mysterious to those with health questions as the science is only recognized in the media when discoveries are made. However, research is going on everyday in the field of gene medicine and breakthroughs, while they dont happen everyday, are happening more often. Gene medicine is beginning to look deeper into how dieseases can be blocked, removed and altered using our own human chemistry. Those with health questions and that want to find out more can read any number of medical periodicals that are being released every month. To read the latest news about health and medicine go here

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GeneMedicine Health Guide

With the aim of commercialization, Takara Bio uses biotechnologies developed over many years to advancethe clinical development of gene therapies that target diseases such as cancer and AIDS.

Takara Bio is currently engaged in the clinical development of the following gene therapies.

Takara Bio acquired the HF10 business from M's Science Corporation in November 2010. HF10 is a spontaneously-occurring attenuated mutant strain of herpes simplex virus type 1 (HSV-1) that shows strong antitumor activity when locally injected into tumors. These kinds of viruses are called oncolytic viruses.

Oncolytic viruses selectively replicate inside, and destroy, tumor tissue without excessively damaging normal tissue. Many oncolytic viruses are produced via gene recombination or foreign gene insertion, but HF10 is a spontaneously-mutated virus that does not contain any foreign genes.

In the United States, Phase I clinical trials targeting solid cancers have been completed and Phase II clinical trials targeting malignant melanoma are now underway.

In Japan, clinical research targeting solid cancers has been underway since December 2011 by the Mie University Hospital, while clinical research targeting pancreatic cancer in combination with existing anti-cancer drugs has been underway since April 2013 by the Nagoya University Hospital. Preparations are also being made to begin conducting Phase I clinical trials in fiscal 2015 for patients with solid cancers in Japan.

Phase I clinical trials (investigator-initiated trials) for the MAGE-A4 antigen-specific T cell receptor (TCR) gene therapy began in March 2014. This therapy targets esophageal cancer using next-generation retroviral vectors developed jointly between Takara Bio and Mie University. These clinical trials are the first attempt in Japan at a genetic immunotherapy for cancer. Takara Bio is also preparing to start up a new projectinvolving NY-ESO-1 antigen-specific TCR gene therapy with the aim of commencing Phase I clinical trials in fiscal 2015.

TCR gene therapy involves taking the patient's lymphocytes and transducing them with the TCR gene, which is capable of recognizing cancer antigens. When re-infused into the patient, the gene-transduced lymphocytes specifically recognize, attack, and eliminate cancer cells. TCR gene therapy is so promising that clinical trials targeting malignant melanoma and other cancers using Takara Bio's RetroNectin method are already being conducted at the National Cancer Institute in the United States.

Takara Bio, in a joint effort with both the University of Pennsylvania and Drexel University College of Medicine, commenced an endoribonuclease MazF-based gene therapy Phase I clinical trial in the United States for patients that have been infected with the human immunodeficiency virus (HIV, otherwise known as the AIDS virus). This clinical trial is scheduled for completion in fiscal 2016.

In the mechanism of AIDS, replication of the virus in HIV-infected immune cells causes deficiencies in the entire immune system. However, MazF-modified T-cells (a type of immune cells) are expected to remain functional even if infected by HIV, by preventing replication of the virus. MazF genes are transduced into patient-derived T-cells ex vivo using retroviral vectors that express MazF conditionally upon HIV infection. The MazF-modified T-cells that are infused back into the patients will cleave the RNA strand of HIV and thereby block the replication of the virus when it infects the transduced T-cells. As a result, this method has the potential to become a gene therapy treatment for AIDS.

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Gene Therapy | Business Outline | TAKARA BIO INC.

Gene therapy carries the promise of cures for many diseases and for types of medical treatment that didn't seem possible until recently. With its potential to eliminate and prevent hereditary diseases such as cystic fibrosis and hemophilia and its use as a possible cure for heart disease, AIDS, and cancer, gene therapy is a potential medical miracle-worker.

But what about gene therapy for children? There's a fair amount of risk involved, so thus far only seriously ill kids or those with illnesses that can't be cured by standard medical treatments have been involved in clinical trials using gene therapy.

As those studies continue, gene therapy may soon offer hope for children with serious illnesses that don't respond to conventional therapies.

Our genes help make us unique. Inherited from our parents, they go far in determining our physical traits like eye color and the color and texture of our hair. They also determine things like whether babies will be male or female, the amount of oxygen blood can carry, and the likelihood of getting certain diseases.

Genes are composed of strands of a molecule called DNA and are located in single file within the chromosomes. The genetic message is encoded by the building blocks of the DNA, which are called nucleotides. Approximately 3 billion pairs of nucleotides are in the chromosomes of a human cell, and each person's genetic makeup has a unique sequence of nucleotides. This is mainly what makes us different from one another.

Scientists believe that every human has about 25,000 genes per cell. A mutation, or change, in any one of these genes can result in a disease, physical disability, or shortened life span. These mutations can be passed from one generation to another, inherited just like a mother's curly hair or a father's brown eyes. Mutations also can occur spontaneously in some cases, without having been passed on by a parent. With gene therapy, the treatment or elimination of inherited diseases or physical conditions due to these mutations could become a reality.

Gene therapy involves the manipulation of genes to fight or prevent diseases. Put simply, it introduces a "good" gene into a person who has a disease caused by a "bad" gene.

The two forms of gene therapy are:

Currently, gene therapy is done only through clinical trials, which often take years to complete. After new drugs or procedures are tested in laboratories, clinical trials are conducted with human patients under strictly controlled circumstances. Such trials usually last 2 to 4 years and go through several phases of research. In the United States, the U.S. Food and Drug Administration (FDA) must then approve the new therapy for the marketplace, which can take another 2 years.

The most active research being done in gene therapy for kids has been for genetic disorders (like cystic fibrosis). Other gene therapy trials involve children with severe immunodeficiencies, such as adenosine deaminase (ADA) deficiency (a rare genetic disease that makes kids prone to serious infection), sickle cell anemia, thalassemia, hemophilia, and those with familial hypercholesterolemia (extremely high levels of serum cholesterol).

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Gene Therapy and Children - KidsHealth

A gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA, act as instructions to make molecules called proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases. The Human Genome Project has estimated that humans have between 20,000 and 25,000 genes.

Every person has two copies of each gene, one inherited from each parent. Most genes are the same in all people, but a small number of genes (less than 1 percent of the total) are slightly different between people. Alleles are forms of the same gene with small differences in their sequence of DNA bases. These small differences contribute to each persons unique physical features.

Genes are made up of DNA. Each chromosome contains many genes.

Genetics Home Reference provides consumer-friendly gene summaries that include an explanation of each genes normal function and how mutations in the gene cause particular genetic conditions.

The Centre for Genetics Education offers a fact sheet that introduces genes and chromosomes.

The Tech Museum of Innovation at Stanford University describes genes and how they were discovered.

The Virtual Genetics Education Centre, created by the University of Leicester, offers additional information on DNA, genes, and chromosomes.

Next: What is a chromosome?

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What is a gene? - Genetics Home Reference

Volume 9, Issue 2 Summary

In patients with type 1 diabetes, pancreatic beta cells self-destruct, leaving the body bereft of insulin. Yasuhiro Ikeda, D.V.M., Ph.D., is working to create a customizable gene and stem cell therapy system that will arrest the loss of these beta cells possibly permanently eliminating the need for insulin injections.

Yasuhiro Ikeda, D.V.M., Ph.D., is spearheading stem cell research in the Mayo Clinic Center for Regenerative Medicine.

Nearly everyone knows someone with diabetes it's hard not to. In the United States, 1 in 3 adults and 1 in 6 children have high blood sugar, according to the National Institutes of Health.

After you eat, glucose is absorbed into your bloodstream and carried throughout your body. Insulin a hormone made by beta cells in your pancreas then signals your cells to take up glucose, helping your body turn the food into energy.

With diabetes, this process can go wrong in two basic ways:Type 1 diabetes results from the body's failure to produce insulin;type 2 diabetes occurs when there's plenty of insulin but the cells lose their ability to perceive its signal. In both cases, cells starve.

Living well with diabetes requires a lifelong commitment to monitoring blood sugar, eating properly, exercising regularly and maintaining a healthy weight. People with type 1 diabetes must also rely on insulin replacement therapy, usually through insulin injections. People with type 2 diabetes might need oral medication.

Still, every year, diabetes kills about 70,000 people in the United States and is a contributing cause in another 160,000 deaths each year, according to the Centers for Disease Control and Prevention.

Yasuhiro Ikeda, D.V.M., Ph.D., a molecular biologist at Mayo Clinic in Rochester, Minn., wants to change that.

After beginning his career as a veterinary feline specialist, Dr. Ikeda had to change course when he developed an allergy to his four-legged patients that made it impossible to be in a room with them. He turned his attention toward research and discovered that his interest in molecular virology had human as well as feline applications.

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Gene therapy and regenerative medicine lend hope to ...

Gene conversion is the process by which one DNA sequence replaces a homologous sequence such that the sequences become identical after the conversion event. Gene conversion can be either allelic, meaning that one allele of the same gene replaces another allele, or ectopic, meaning that one paralogous DNA sequence converts another.

Allelic gene conversion occurs during meiosis when homologous recombination between heterozygotic sites results in a mismatch in base pairing. This mismatch is then recognized and corrected by the cellular machinery causing one of the alleles to be converted to the other. This can cause non-Mendelian segregation of alleles in germ cells.[1]

Recombination does not only occur during meiosis, but also as a mechanism for repair of double-strand breaks (DSBs) caused by DNA damage. These DSBs are usually repaired using the sister chromatid of the broken duplex and not the homologous chromosome, so they would not result in allelic conversion. Recombination also occurs between homologous sequences present at different genomic loci (paralogous sequences) which have resulted from previous gene duplications. Gene conversion occurring between paralogous sequences (ectopic gene conversion) is responsible for concerted evolution of gene families.[1][2]

Conversion of one allele to the other is often due to base mismatch repair during homologous recombination: if one of the four chromatids during meiosis pairs up with another chromatid, as can occur because of sequence homology, DNA strand transfer can occur followed by mismatch repair. This can alter the sequence of one of the chromosomes, so that it is identical to the other.

Meiotic recombination is initiated through formation of a double-strand break (DSB). The 5 ends of the break are then degraded, leaving long 3 overhangs of several hundred nucleotides. One of these 3 single stranded DNA segments then invades a homologous sequence on the homologous chromosome, forming an intermediate which can be repaired through different pathways resulting either in crossovers (CO) or noncrossovers (NCO). At various steps of the recombination process, heteroduplex DNA (double-stranded DNA consisting of single strands from each of the two homologous chromosomes which may or may not be perfectly complementary) is formed. When mismatches occur in heteroduplex DNA, the sequence of one strand will be repaired to bind the other strand with perfect complementarity, leading to the conversion of one sequence to another. This repair process can follow either of two alternative pathways as illustrated in the Figure. By one pathway, a structure called a double Holliday junction (DHJ) is formed, leading to the exchange of DNA strands. By the other pathway, referred to as Synthesis Dependent Strand Annealing (SDSA), there is information exchange but not physical exchange. Gene conversion will occur during SDSA if the two DNA molecules are heterozygous at the site of the recombinational repair. Gene conversion may also occur during recombinational repair involving a DHJ, and this gene conversion may be associated with physical recombination of the DNA duplexes on the two sides of the DHJ.

Biased gene conversion (BGC) occurs when one allele has a higher probability of being the donor than the other in a gene conversion event. For example, when a T:G mismatch occurs, it would be more or less likely to be corrected to a C:G pair than a T:A pair. This gives that allele a higher probability of transmission to the next generation. Unbiased gene conversion means that both possibilities occur with equal probability.

GC-biased gene conversion (gBGC) is the process by which the GC content of DNA increases due to gene conversion during recombination.[2] Evidence for gBGC exists for yeasts and humans and the theory has more recently been tested in other eukaryotic lineages.[3] In analyzed human DNA sequences, crossover rate has been found to correlate positively with GC-content.[2] The pseudoautosomal regions (PAR) of the X and Y chromosomes in humans, which are known to have high recombination rates also have high GC contents.[1] Certain mammalian genes undergoing concerted evolution (for example, ribosomal operons, tRNAs, and histone genes) are very GC-rich.[1] It has been shown that GC content is higher in paralogous human and mouse histone genes that are members of large subfamilies (presumably undergoing concerted evolution) than in paralogous histone genes with relatively unique sequences.[4] There is also evidence for GC bias in the mismatch repair process.[1] It is thought that this may be an adaptation to the high rate of methyl-cytosine deamination which can lead to CT transitions.

The Fxy or Mid1 gene in some mammals closely related to house mice (humans, rats, and other Mus species) is located in the sex-linked region of the X chromosome. However, in Mus musculus, it has recently translocated such that the 3 end of the gene overlaps with the PAR region of the X-chromosome, which is known to be a recombination hotspot. This portion of the gene has experiences a dramatic increase in GC content and substitution rate at the 3rd codon position as well as in introns whereas the 5 region of the gene which is X-linked has not. Because this effect is present only in the region of the gene experiencing increased recombination rate, it must be due to biased gene conversion and not selective pressure.[2]

GC content varies widely in the human genome (4080%), but there seem to be large sections of the genome where GC content is, on average, higher or lower than in other regions.[1] These regions, although not always showing clear boundaries, are known as isochores. One possible explanation for the presence of GC-rich isochores is that they evolved due to GC-biased gene conversion in regions with high levels of recombination.

Studies of gene conversion have contributed to our understanding of the adaptive function of meiotic recombination. The ordinary segregation pattern of an allele pair (Aa) among the 4 products of meiosis is 2A:2a. Detection of infrequent gene conversion events (e.g. 3:1 or 1:3 segregation patterns during individual meioses) provides insight into the alternate pathways of recombination leading either to crossover or non-crossover chromosomes. Gene conversion events are thought to arise where the A and a alleles happen to be near the exact location of a molecular recombination event. Thus it is possible to measure the frequency with which gene conversion events are associated with crossover or non-crossover of chromosomal regions adjacent to, but outside, the immediate conversion event. Numerous studies of gene conversion in various fungi (which are especially suited for such studies) have been carried out, and the findings of these studies have been reviewed by Whitehouse.[5] It is clear from this review that most gene conversion events are not associated with outside marker exchange. Thus, most gene conversion events in the several different fungi studied are associated with non-crossover of outside markers. Non-crossover gene conversion events are mainly produced by Synthesis Dependent Strand Annealing (SDSA).[6] This process involves limited informational exchange, but not physical exchange of DNA, between the two participating homologous chromosomes at the site of the conversion event, and little genetic variation is produced. Thus explanations for the adaptive function of meiotic recombination that focus exclusively on the adaptive benefit of producing new genetic variation or physical exchange seem inadequate to explain the majority of recombination events during meiosis. However, the majority of meiotic recombination events can be explained by the proposal that they are an adaptation for repair of damages in the DNA that is to be passed on to gametes.[7][8]

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Gene conversion - Wikipedia, the free encyclopedia