Posts Tagged ‘biology’

HIV / AIDS: Biology, Statistics, Risk Factors, Symptoms, Genetics, Tests

May 11, 2010

About HIV/AIDS

Human immunodeficiency virus (HIV) is a retrovirus that can result in acquired immunodeficiency syndrome (AIDS). Nine out of ten untreated individuals with HIV will develop AIDS in 10-15 years or sooner after acquiring the disease. With anti-retroviral treatment, patients have an increased life expectancy. Without treatment, patients usually die within a year.

AIDS is now considered to be pandemic. Between 1981 and 2006 it is estimated that 25 million people died from AIDS. In 2007 worldwide statistics show the following statistics:

  • 330,000 children died from AIDS
  • 2.1 million people died from AIDS
  • 33.2 million people lived with AIDS.

Over 75% of those deaths originated in sub-Saharan Africa.

The immunodeficiency affects every organ of the body. Certain conditions are more likely in a person with HIV including:

  • bacterial infections
  • cervical cancer
  • fungal infections
  • gastrointestinal infections
  • lymphomas
  • parasitic infections
  • pulmonary infections
  • tumors and malignancies
  • viral infections.

Symptoms develop from the body’s lack of having a regularly functioning immune system. Symptoms include:

  • chills
  • fever
  • sweats
  • swollen glands
  • weakness
  • weight loss.

Research has now determined that some individuals have HIV genetic resistance. Other people are more susceptible to HIV/AIDS. The risk factors that increase one’s chance of getting HIV include:

  • anal sex
  • blood exposure
  • blood transfusion recipients between 1978 and 1985
  • intravenous drug users who share syringes and/or needles
  • mother-infant transmission
  • needle stick injury
  • oral sex
  • people who have had multiple sex partners
  • people who have had sex with a man who has had sex with another man
  • sexually transmitted diseases (STD)
  • unprotected sex.

The Biology of HIV/AIDS

The human immunodeficiency virus attacks all the organs of the immune system. These include the CD4+ T cells. AIDS leads to failure of the entire immune system because CD4+ cells normally protect the body from infections. Without them opportunistic infections attack the body and can cause death.

HIV is spread from individual to individual by transfer of body fluids. This occurs by having unprotected sexual intercourse, by sharing needles or from mother to child. Infected fluids include:

  • blood
  • breast milk
  • pre-ejaculate
  • semen
  • vaginal fluid.

The Genetics of HIV/AIDS

HIV resistance is an inherited trait in about 1% of the white population, but it is rare in the African and Asian populations. This genetic disease resistance was first discovered when doctors realized that a small percentage of individuals who screened positive for HIV did not get AIDS. Chemokine coreceptors (CCR) were found to be responsible for suppressing infection. Researchers later found that people with a defective CCR5 gene are more resistant to HIV-1.

AIDS and genetic resistance research had determined that a deletion of a portion of the CC-CKR-5 gene makes the gene inaccessible to the virus. Some populations have a higher percentage of individuals with this mutation. This means that this mutation has a more recent origin.

Interpreting Your Genetic Test Results

DNA test results will determine if an individual is susceptible to HIV/AIDS or not. If one has the mutation in the gene that makes one resistant, it can be passed on to children. Those who are homozygous, or have two genes that are defective, are extremely resistant to the disease. Even though some people have a resistance to HIV, this virus has a very short replication cycle and can mutate within a short period of time. This means that even if an individual has a mutation in this gene, it does not mean that they will not get the disease.

If an individual’s genetic test results determine that they lack the “resistance” gene, this does not make the individual more susceptible to the disease than the general population. It just means that they must be careful and make the correct lifestyle choices.

 Frequently Asked Questions about HIV/AIDS Resistance

  • How safe is the blood supply in the United States?

The blood supply is the safest in the entire world. HIV testing began in 1985. All blood that was donated after this time has been HIV free. Additional testing has been added since this time. When blood has been identified as being infected, it is discarded.

  • Why is it so difficult to suppress AIDS?

The AIDS virus mutates at such a rapid rate that it is difficult to keep up with it. The best treatment at the time may be able to suppress most of the virus, but since it replicates so rapidly, at least some of the virus has become immune to the treatment.

  • Why do treatments sometimes fail?

Powerful combinations of cocktails exist to attempt to suppress AIDS. One of the reasons these treatments fail to work is the noncompliance of the patient to taking the drugs. Side effects may be unpleasant, dietary restrictions may be difficult and the act of taking dozens of pills may be daunting. If a patient does not take a dose, it could allow drug-resistant mutants to replicate and take the system over.

Recent News on HIV/AIDS Resistance

More recent research has determined that two separate genes, KIR3DL1 and HLA-B*57, are involved in resistance to AIDS. If an individual inherits a version of these genes, they might be more resistant to getting AIDS. The mechanism has not yet been explained, but this is good news.

Marine Biology Camos and Trips

May 11, 2010

Marine biology camps and trips are now available in many cities near the coast all over the world. They offer a wide variety of activities for groups or individuals. It is an excellent opportunity for children to explore their interests in the field of Marine Sciences. They can experience on a daily basis a day camp or a multi-night sleepover in a residential camp. They give children hands-on close-up experience with the animals. Kids can interact with, feed and swim with endangered wildlife.

Where To Find Them

Marine Biology Summer Camps are held all over the US in coastal cities. SeaWorld holds its Adventure Camps in Tampa Bay and Orlando, FL, San Antonio, TX and San Diego, CA. Marine Bio Camp at Sea starts off in Ft. Lauderdale, FL, and the majority of time is spent in Bimini in the Bahamas, 55 miles to the east. Catalina is 25 miles from the coast of Long Beach, CA.

Similar camps are also offered in Wilmington, NC, Cambria, CA, Grand Manan Island, Maine, Canada, Big Pine Key, FL, Seal Harbor, Maine, Awendaw, SC, and many other locations. Some are held out of the USA in the Caribbean, Bahamas, Costa Rica, Australia, Honduras, Ecuador and the Galapagos Islands.

Activities at Marine Biology Camp

Because there are so many options to choose from, activities at only several of the above locations have been described below to give an example of what is available. Each has its own advantages, but they cater to the child and the age range.

SeaWorld hosts activities for children from grade 4 through college. Classes for younger kids include getting to know animals, learning how to care for the animals and how to boogie board. Classes for older kids teach what a person needs to know pursuing a career in animal care field. This is a hands-on look at preparing animal food, clean-up and working with animals and the people who care for them. They also learn how to surf and snorkel.

Marine Bio Camp at Sea accepts children from age 14 to 18. They explore the work that is performed on research vessels. They learn about and swim with dolphins. The gentle introduction to the sea offers an opportunity to become comfortable with the sea.

Catalina Junior Sea Camp is for kids 8 to 12. These kids enjoy snorkeling, sailing, kayaking, hiking trails and learning about the ocean. After snorkeling and seeing hundreds of fish in the ocean, kids come back and learn more about these fish species in the fish and shark labs which are stocked with fish in aquariums, pictures, specimens and exhibits. There is also an algae lab where kids learn the many types and uses of seaweed today. They are also taken aboard a research flat top boat and brought out to sea to perform experiments. Afterwards, the samples are taken back and microscopes allow the children to see plankton in the lab. There are also invertebrate and marine mammal labs in which the children can touch the invertebrates in tanks and see and touch skeletons of mammals.

Catalina Sea Camp is for kids 12 to 17. These older kids SCUBA, snorkel, sail, surf, and kayak. They also take courses in Marine Biology, Invertebrates and Ichthyology, Ocean Exploration and Discovery, Aquarium Design, Maintenance and Behind the Scenes, Hot Topics in Marine Conservation, and Seafood Cookery. They also take courses in Arts and Crafts that include painting, nature sketching and photography, jewelry design and creation. Kids also have an opportunity to help plant to revegitate the island clean up the shorelines.

Cost

Six nights at SeaWorld costs $1025 for grades 4 to 6, $1075 for grades 7 to 9 and $1125 for career camp for grades 10 to 12. Tuition runs from $2495 at Marine Bio Camp at Sea. Catalina Junior Sea Camp costs $1150 for one week. Catalina Sea Camp costs $3300 for three weeks.

Breast Cancer: Symptoms, Causes, Genetics and Genetic Testing

May 11, 2010

Breast cancer is defined as cancer that originates in the breast cells. Women are 100 times more likely to develop it than men. It is the second most common form of cancer after lung cancer. Every year about 200,000 American women are diagnosed with breast cancer. It killed half a million people in 2005.

Breast cancer can spread through the lymphatic system or blood vessels to other parts of the body. This spread is referred to as metastasizing. It can metastasize to the lungs, brain, liver or bones.

There are non-specific and specific symptoms. Non-specific means that they could be symptoms for some other condition. Some non-specific symptoms include:

  • bone and joint pain
  • chills
  • discharge from one nipple
  • fever
  • jaundice.

Some specific symptoms include change in the size or shape of the breast or nipple and a lump in the breast or the lymph nodes in the armpit and/or collarbone

Inflammatory breast cancer occurs when breast cancer cells enter the small lymph vessels next to the skin. Symptoms include:

  • orange peel texture of the skin
  • pain
  • redness
  • swelling
  • warmth.

Paget’s disease of the breast also manifests itself in the skin and resembles eczema. Symptoms may include:

  • discharge
  • itching
  • lump
  • mild flaking of the skin around the nipple
  • redness
  • sensitivity
  • tingling.

Causes of Breast Cancer

Breast cancer stems from a combination of hereditary and environmental influences. People who have a family history with multiple cases of breast or ovarian cancer are at higher risk of getting breast cancer. Breast cancer is more common if one has an Ashkenazi (Eastern European) Jewish background. It usually occurs sporadically and is not inherited. Some risk factors include:

  • age
  • alcohol intake
  • childbearing
  • environmental factors like radiation and tobacco use
  • high fat intake
  • hormones
  • obesity
  • sex.

Genetics of Breast Cancer

About 5-10% of those diagnosed have a hereditary form of breast cancer. If a person inherits a mutation in the breast cancer 1 (BRCA1) or breast cancer 2 (BRCA2) genes, she is at higher risk of developing breast cancer. It is rare to inherit a mutation. Only one in 1000 has a mutation in one of these genes.

People who have the mutation may get cancer or may lead a long healthy life. Having a mutation does not guarantee the individual will develop cancer. About 13% of the population develops breast cancer. Those with a mutation in either of these genes are three to seven times more likely to get it.

How Genetic Testing Is Done for Breast Cancer Patients

Genetic testing looks at sequences of DNA to identify changes. The sequence of DNA has been determined for healthy people. If there is a mutation in a gene, it can make a person more susceptible to certain diseases. Certain inherited conditions have been linked to mutations in certain genes. Genetic testing is the comparison of the sequence of sample DNA to the agreed upon sequence for a normal gene to identify these risks.

Genetic testing for breast cancer is only performed on people who are at high risk of getting cancer. This blood test identifies the presence of mutations in the BRCA genes. A breast cancer genetic testing lab determines the patient’s risk of getting cancer. Genetic counseling is included in this test to make sure people are informed of their risk and options for the future.

Progress toward a Cure

Treatment for breast cancer today relies heavily on surgery, chemotherapy and radiation. Gene therapy is one option of curing breast cancer. It is not yet possible, but eventually doctors will be able to fix the mutations in the genes. Research continues to search for more genes that influence a person’s risk of developing breast cancer.

Some ways to prevent breast cancer include:

  • Chemoprevention – Some medications, such as tamoxifen, decrease one’s chance of developing cancer.
  • Mastectomy – Preventative removal of breast tissue reduces the risk of cancer by 90%.
  • Surveillance – More frequent self-exams, clinical exams, MRI’s and mammograms discover cancer earlier.

Prostate Cancer: Biology, Genetics, Prevalence

May 11, 2010

Prostate cancer can only occur in men because the prostate is a gland which exists in the male reproductive system. Prostate cancer detection begins with screening for prostate specific antigen (PSA). Detection occurs less often when symptoms develop or by physical examination. Prostate cancer diagnosis is confirmed by biopsy. Risk factors include age, ethnicity, family history and diet.

Prostate cancer is the most common cancer in American men. It can be painful, make urinating difficult and cause erectile dysfunction. Men who are at average risk of prostate cancer have a 14% chance of developing prostate cancer by the time they are 80 years of age. Prostate cancer is the second leading cause of cancer death in men. Many men develop prostate cancer, do not have any symptoms and die of other causes related to old age.

Biology of Cancer

Cancer occurs when genes mutate and do not produce the correct regulatory proteins which normally control cell functions. Cells then multiply out of control. Cancer can spread to other parts of the body, such as bones and lymph nodes. Genes can mutate before a person is born. This is considered to be hereditary. This type of cancer can be inherited by offspring in future generations. Genes can also mutate during a person’s lifetime. The cells derived from this line would then be immortal.

Prostate Cancer Genetics

Most prostate cancer is sporadic, so 75% of individuals with prostate cancer mutated genes after birth. Only 5% of men inherit prostate cancer. The remaining 20% develop familial prostate cancer, which means that a combination of environmental and shared genes resulted in cancer.

Genetics has been implicated in the development of prostate cancer. Every cell contains two copies of each gene; one copy originates from the mother and one from the father. When prostate cancer is inherited, it follows an autosomal dominant inheritance. This means that the mutation only has to occur in one copy of the gene for the individual to be at higher risk of developing cancer. Each child has 50% chance of inheriting the mutation causing prostate cancer from a parent who has the mutation.

The only way a person can know if they are at high risk of having a genetic mutation is genetic testing. Since there is no genetic test for prostate cancer, one must rely on family history. If a man has a strong family history of prostate cancer, he can participate in prostate cancer research to determine what the genes are that are correlated with it.

Prostate cancer risk factors include mutations in several genes. A gene on chromosome 17 is associated with increased risk of prostate cancer.  Research must be continued to verify these findings to determine if they can be used for genetic testing in the future. Several other mutated genes have been identified as being responsible for increased likelihood of developing prostate cancer.

Prevalence of Prostate Cancer

Rates of prostate cancer vary widely throughout the world. It is least prominent in South and East Asia, more common in Europe and most common in the United States. In 2008, about 186,000 men in the US will be diagnosed with prostate cancer. It normally develops in men over 50 years old. An estimated 28,000 deaths will occur from prostate cancer. Although the incidence of prostate cancer is decreasing overall, black men are twice as likely to develop this cancer as white men.

Progress toward a Cure

Prostate cancer prevention may be in the near future. Men can determine their risk factor through their family history and attempt to control certain environmental and lifestyle factors. These factors include a balanced diet, healthy weight, exercising, limiting alcoholic beverages and avoiding tobacco products. Eventually research will determine which genetic mutations are correlated with prostate cancer.