Medical Technology—The Genetic Forefront

surgery

A patient receives an operation following an adverse drug reaction.

A college student comes down with the flu. Worried about missing class, he goes to an emergency clinic and is given a prescription for an antiviral flu drug. Thirty minutes after taking the first pill, he is gasping for breath and his heart is racing. He is rushed to the hospital, where doctors tell him he has had an adverse reaction to his antiviral medication.

A Cure Worse than the Disease

Usually, medications cause only mild side effects, such as drowsiness, headaches, or nausea. Occasionally, patients are allergic to medicines and break out in hives or go into shock. But sometimes reactions to drugs are more serious. In the United States, about 2.2 million patients per year are hospitalized because of adverse drug reactions, and more than 100,000 die. No doctor intends for a drug’s side effects to be worse than the disease it is meant to cure. Nonetheless, the current process of prescribing drugs based on medical and family history is one of trial and error.

Customized Drugs

An emerging field called pharmacogenomics is revolutionizing the prescription process. Pharmacogenomics is the study of how genetic variations can cause different people to react in different ways to the same drugs. In most cases, for example, genetics determines the way in which—and the speed at which—a person’s body breaks down a medication. If a person’s body metabolizes a drug too quickly, the drug may not be effective. If the drug is metabolized too slowly, a standard dose may be too much.

In the future, a patient in need of a prescription could have a blood test, and health care workers could run the blood test results through a computer using biochip, or microarray, technology. In hours, a doctor could have enough information about a patient’s genetic background to predict how the person would respond to a certain drug and decide whether to adjust the dose. Individuals may even be able to have their genomes mapped and put onto cards to take to doctor visits. Biochip technology is not yet available in most doctors’ offices, but many drugs are already being labeled with pharmacogenomic information advising doctors that patients with certain genetic variations may need a lower or higher dose of the medication.

Gene Therapy

While pharmacogenomics can provide doctors with more information about their patients, gene therapy may someday provide them with another tool. Some diseases, such as Alzheimer’s or hemophilia, have a strong genetic basis. Doctors are beginning clinical trials in which they treat Alzheimer’s by injecting genes, during surgery, into the area of the brain that has the most affected brain cells. The new genes will instruct brain cells to make more of a protein that keeps nerve cells alive longer.

Doctors are also beginning to treat hemophilia using gene therapy. One method is to inject genes into the liver. In other clinical trials, new DNA is inserted into a virus that can then be used to “infect” a patient’s diseased cells. The field of gene therapy is developing slowly because it requires researchers to accomplish several feats. First, they must engineer, and test, a gene that is safe to insert into humans. Then they must find a way to get the gene to the part of the body that needs it—often using nanotechnology. Much of this research is still being done in animals, but there have been a few successful gene therapy trials in humans.

Other Uses

A scientist examines different types of genetically modified rice plants.

New uses for DNA technology offer both solutions and hard choices. Some of the more difficult questions involve the following kinds of projects:

  • Researchers can alter the DNA of viruses to make them harmless and usable as vaccines.
  • Scientists are developing transgenic animals that can make organs for human transplants.
  • Researchers are engineering crops that contain vaccines that could be administered orally. These
    vaccines would be easier to grow and distribute in developing countries than are current vaccines.

Unanswered Questions

Some exciting new pharmacogenomic research is being done by the Human Genome Project. However, many challenges must be addressed before pharmacogenomics can have widespread clinical application.

  • Many current studies of patients’ drug responses have conflicting results, likely due to small sample
    sizes, different criteria for measuring a good response, and different population groups.
  • Patients’ responses to a drug may be caused by many genes. Scientists will need to study the effect
    of multiple genes to determine response.
  • Genotype testing may increase short-term healthcare costs, raising questions about who will pay and who will have access to the technology.

UPDATES: Straight from the Headlines

Biochips

Doctors can now analyze a patient’s DNA by using biochip technology. A biochip is a solid surface to which tiny strands of DNA are attached. When this type of screening becomes clinically feasible, it will take several steps.

  1. DNA will be extracted from the patient’s blood.
  2. A biochip will be used to map the patient’s genome. Computer software could scan the genome looking for single nucleotide polymorphisms (called SNPs, or “snips”), places where human DNA is more variable.
  3. A doctor will then compare the patient’s genomic results with the latest available medical research.

Ideally, the resulting prescription should be customized to the patient. If a patient has a variation that is found in a small percentage of the population, however, the doctor is unlikely to have enough data about possible reactions.

Cancer Geneticist in Action

Dr. Olufunmilayo Olopade
Title: Director, Center for Clinical Cancer Genetics, University of Chicago
Education: M.D., University of Ibadan, Nigeria

Breast cancer occurs in many different forms. It has been most widely studied in Caucasian women but takes a very different form in women of African ancestry. Breast cancer hits women of African ancestry earlier and more aggressively than it does Caucasian women. Dr. Olufunmilayo Olopade wants to learn why. Working with scientists in her native Nigeria, Dr. Olopade compared gene expression in samples of cancer tissue from African women with samples of cancer tissue from Canadian women. She found that cancer cells from the African women often lacked estrogen receptors. This finding means that many of the standard treatments are not effective for this group of women.

Dr. Olopade’s work will have a huge impact on breast cancer screening and treatment in women of
African ancestry. “Cancer doesn’t start overnight,” she says. “We can develop strategies for preventing it.”

Comments

  1. amir howard,ericka chrstensen,Eduardo Morales,steven says:

    i think the whole story is about scentific technology that can help use prevent adverse reactions from from medacation

  2. Group 3-Michail Demeke,Tyrique,Akira Rose,Emani,Cody says:

    The article is more geared to patients that have been through this kind of situation. It is an informative article that lets us understand the risks of taking medication that could be lethal. Since it was written September 1, 2011 there might have been more medical advancements since then that could help with this situation. Key vocabulary that stood out was pharmacogenomics, which is the study of how different people react to different types of medication. Also Biochips have been emerged and this advancement in technology allows scientists to be able to analyze a patients DNA. Questions that we could not find unanswered where, why were healthcare costs to high because of the technology? Also who will be able to get help if the technology is discovered?

  3. Bobbi Miller says:

    Naya, DJ, Feroze, Shadasia

    At the beginning of the article , we were appalled to see the large number of individuals that are affected by reactions to drugs. We never realized that sometimes a person’s reaction to the disease that they is worst than the actual disease. In response to the overwhelming amount of drug reaction related injuries, scientists have used customized drugs and gene therapy to help view how patients will react to different drugs. We were intrigued to find out the various technology used to achieve this technology. For example, the biochip technology can easily give a customized prescription that prevents harmful reactions. This technology shows how genetics have come to the forefront of medicine.

  4. Jordan Banks says:

    Pharmacogenomics allows pharmacist to create stronger and more effective drugs for society, but these innovations will come at a hefty cost. Adverse reactions from new and less common drugs may cause serious allergic reactions that may kill the people who use them. Pharmacist must allow a drug to be test more often and more thoroughly before these drugs are put on the market to be utilized. The possibility of creating more effective pharmaceutical drugs that can eliminate certain disease symptoms is very promising for society, but the risk of these new drugs actually being safe for humans is too high. I believe that the stronger the new drug is the more thoroughly is must be tested, because if the drug isnt tested for a proper amount of time stronger and more serious reactions may be consequences to the people who utilize the drug.

  5. Zaria Thomas, Kiara Jenkins, Destiny Matthews, Alexus Moore, Desiree Cross' says:

    Doctors are beginning clinical trials which are also known as Gene Therapy. Using gene therapy it can reduce the risk of adverse drug reactions.

  6. that very very wrong, by right if a person is sick and is taken to the doctor is the doctor responsibility to ask that person some question, in that question you are going to know if the medicine is good for that person or not.Like have you taken this medicine,what kind of sickness you have. I THINK, THAT IS A PERFECT WAY.

What Do You Think?

*