Test tube sperm an insight to fertility

LONDON: A team of British scientists claimed yesterday to have created human sperm using embryonic stem cells in a medical first they say will lead to a better understanding of fertility.

Researchers led by Karim Nayernia at Newcastle University and the North East England Stem Cell Institute developed a technique that allows the creation of human sperm in the laboratory.

They stressed that the sperm, developed from stem cells with XY chromosomes (male), would not be used for fertility treatment, as this is prohibited by British law and in any case is not their main interest.

"This is an important development as it will allow researchers to study in detail how sperm forms and lead to a better understanding of infertility in men - why it happens and what is causing it," Professor Nayernia said.

"This understanding could help us develop new ways to help couples suffering infertility so they can have a child which is genetically their own."

He said more investigation was needed to decide whether the so-called in-vitro derived sperm could be used as a fertility treatment, for example, for boys who became infertile after receiving chemotherapy for cancer.

While such a treatment would not be likely to be developed for at least a decade, Professor Nayernia said legislation should be put in place "sooner rather than later" to allow the technique to be licensed.

The team's work involved developing stem cells that had XY chromosomes into germline cells - cells that can can pass their genetic material to future generations.

These were then prompted to complete meiosis, or cell division, which produced "fully mature, functional sperm".

Stem cells are immature cells that can develop into different cell types.

The scientists tried to develop cells with XX chromosomes (female) in the same way but they did not progress beyond early stage sperm, called spermatagonia. The team concluded that the genes on a Y chromosome are essential for sperm maturation.

The research, published in the journal Stem Cells and Development, could lead to a better understanding of how genetic diseases are passed on.

HIV is found to be fast

Human immunodeficiency virus, once considered a slow if stealthy invader, actually works incredibly fast at disarming key immune fighters in the body, scientists at Duke University and UNC-Chapel Hill reported Monday.

What's more, HIV strikes an army of immune cells that scientists previously believed were less vulnerable early on.

The findings, reported in the online journal PloS Medicine, provide a better understanding of how to develop a vaccine to protect against the virus that causes AIDS. It newly infects an estimated 56,300 people a year in the United States.

"It's very helpful to us to know exactly what's going on" with the immune system, said Dr. Barton Haynes, who is an immunologist at Duke, director of the Center for HIV/AIDS Vaccine Immunology and the senior author of the study.

The insight was gained using technology pioneered at UNC-Chapel Hill that detects the virus within days of infection, rather than months. North Carolina began using the early detection methods at public health clinics, and a group of newly diagnosed patients agreed to participate in a study of how the immune system is affected at early stages.

Findings from these patients showed that three lines of attack by the immune system are quickly neutralized by HIV.

First, the virus wipes out the nurturing centers of the gut that harbor so-called B cells, infection fighters that originate in the bone marrow and congregate in areas of the small intestine.

In addition, HIV triggers a sort of smoke screen that provides it cover while the B cells spring into action, armed to fight every threat imaginable but unable to effectively target the real danger.

Finally, the virus also wipes out helper B cells, which are necessary for an effective response.

"To everyone's surprise, they found all this damage and cell death," said Dr. David Margolis, an AIDS researcher at UNC-CH and one of the study authors. He said the surprise was both in the timing of the onslaught, and in the target.

For years, HIV researchers focused on a different immune fighter -- T cells, killer cells formed not in the bone marrow, but in the thymus gland. HIV was known to take over T cells, destroying their ability to fight infections. But even with the new insights, Haynes said, scientists have a formidable task developing a vaccine.

"It would have to be different than any other vaccine made," Haynes said.

Theraclone Gets Funding for HIV

Theraclone Sciences, the Seattle-based developer of antibody drugs formerly known as Spaltudaq, said today it has received additional funding from the International AIDS Vaccine Initiative to continue developing antibodies that could lead to an AIDS vaccine, or new treatment. The HIV virus has dodged past attempts to develop antibody-based treatments or vaccines, because it mutates quickly to avoid them, but Theraclone's approach follows clues from the immune systems of people with rare immune systems that give them natural protection against the virus, as I described in this April feature. Financial terms weren't disclosed.

More on Cancer...

Genes - the DNA type
Cells can experience uncontrolled growth if there are damages or mutations to DNA, and therefore, damage to the genes involved in cell division. Four key types of gene are responsible for the cell division process: oncogenes tell cells when to divide, tumor suppressor genes tell cells when not to divide, suicide genes control apoptosis and tell the cell to kill itself if something goes wrong, and DNA-repair genes instruct a cell to repair damaged DNA.

Cancer occurs when a cell's gene mutations make the cell unable to correct DNA damage and unable to commit suicide. Similarly, cancer is a result of mutations that inhibit oncogene and tumor suppressor gene function, leading to uncontrollable cell growth.

Carcinogens
Carcinogens are a class of substances that are directly responsible for damaging DNA, promoting or aiding cancer. Tobacco, asbestos, arsenic, radiation such as gamma and x-rays, the sun, and compounds in car exhaust fumes are all examples of carcinogens. When our bodies are exposed to carcinogens, free radicals are formed that try to steal electrons from other molecules in the body. Theses free radicals damage cells and affect their ability to function normally.

Genes - the family type
Cancer can be the result of a genetic predisposition that is inherited from family members. It is possible to be born with certain genetic mutations or a fault in a gene that makes one statistically more likely to develop cancer later in life.

Other medical factors
As we age, there is an increase in the number of possible cancer-causing mutations in our DNA. This makes age an important risk factor for cancer. Several viruses have also been linked to cancer such as: human papillomavirus (a cause of cervical cancer), hepatitis B and C (causes of liver cancer), and Epstein-Barr virus (a cause of some childhood cancers). Human immunodeficiency virus (HIV) - and anything else that suppresses or weakens the immune system - inhibits the body's ability to fight infections and increases the chance of developing cancer.

What are the symptoms of cancer?
Cancer symptoms are quite varied and depend on where the cancer is located, where it has spread, and how big the tumor is. Some cancers can be felt or seen through the skin - a lump on the breast or testicle can be an indicator of cancer in those locations. Skin cancer (melanoma) is often noted by a change in a wart or mole on the skin. Some oral cancers present white patches inside the mouth or white spots on the tongue.

Other cancers have symptoms that are less physically apparent. Some brain tumors tend to present symptoms early in the disease as they affect important cognitive functions. Pancreas cancers are usually too small to cause symptoms until they cause pain by pushing against nearby nerves or interfere with liver function to cause a yellowing of the skin and eyes called jaundice. Symptoms also can be created as a tumor grows and pushes against organs and blood vessels. For example, colon cancers lead to symptoms such as constipation, diarrhea, and changes in stool size. Bladder or prostate cancers cause changes in bladder function such as more frequent or infrequent urination.

As cancer cells use the body's energy and interfere with normal hormone function, it is possible to present symptoms such as fever, fatigue, excessive sweating, anemia, and unexplained weight loss. However, these symptoms are common in several other maladies as well. For example, coughing and hoarseness can point to lung or throat cancer as well as several other conditions.

When cancer spreads, or metastasizes, additional symptoms can present themselves in the newly affected area. Swollen or enlarged lymph nodes are common and likely to be present early. If cancer spreads to the brain, patients may experience vertigo, headaches, or seizures. Spreading to the lungs may cause coughing and shortness of breath. In addition, the liver may become enlarged and cause jaundice and bones can become painful, brittle, and break easily. Symptoms of metastasis ultimately depend on the location to which the cancer has spread.

How is cancer classified?
There are five broad groups that are used to classify cancer.

--Carcinomas are characterized by cells that cover internal and external parts of the body such as lung, breast, and colon cancer.

--Sarcomas are characterized by cells that are located in bone, cartilage, fat, connective tissue, muscle, and other supportive tissues.

--Lymphomas are cancers that begin in the lymph nodes and immune system tissues.

--Leukemias are cancers that begin in the bone marrow and often accumulate in the bloodstream.

--Adenomas are cancers that arise in the thyroid, the pituitary gland, the adrenal gland, and other glandular tissues.

Cancers are often referred to by terms that contain a prefix related to the cell type in which the cancer originated and a suffix such as -sarcoma, -carcinoma, or just -oma. Common prefixes include:

Adeno- = gland

Chondro- = cartilage

Erythro- = red blood cell

Hemangio- = blood vessels

Hepato- = liver

Lipo- = fat

Lympho- = white blood cell

Melano- = pigment cell

Myelo- = bone marrow

Myo- = muscle

Osteo- = bone

Uro- = bladder

Retino- = eye

Neuro- = brain

How is cancer diagnosed and staged?
Early detection of cancer can greatly improve the odds of successful treatment and survival. Physicians use information from symptoms and several other procedures to diagnose cancer. Imaging techniques such as X-rays, CT scans, MRI scans, PET scans, and ultrasound scans are used regularly in order to detect where a tumor is located and what organs may be affected by it. Doctors may also conduct an endoscopy, which is a procedure that uses a thin tube with a camera and light at one end, to look for abnormalities inside the body.


Extracting cancer cells and looking at them under a microscope is the only absolute way to diagnose cancer. This procedure is called a biopsy. Other types of molecular diagnostic tests are frequently employed as well. Physicians will analyze your body's sugars, fats, proteins, and DNA at the molecular level. For example, cancerous prostate cells release a higher level of a chemical called PSA (prostate-specific antigen) into the bloodstream that can be detected by a blood test. Molecular diagnostics, biopsies, and imaging techniques are all used together to diagnose cancer.

After a diagnosis is made, doctors find out how far the cancer has spread and determine the stage of the cancer. The stage determines which choices will be available for treatment and informs prognoses. The most common cancer staging method is called the TNM system. T (1-4) indicates the size and direct extent of the primary tumor, N (0-3) indicates the degree to which the cancer has spread to nearby lymph nodes, and M (0-1) indicates whether the cancer has metastasized to other organs in the body. A small tumor that has not spread to lymph nodes or distant organs may be staged as (T1, N0, M0), for example.

TNM descriptions then lead to a simpler categorization of stages, from 0 to 4, where lower numbers indicate that the cancer has spread less. While most Stage 1 tumors are curable, most Stage 4 tumors are inoperable or untreatable.

How is cancer treated?
Cancer treatment depends on the type of cancer, the stage of the cancer (how much it has spread), age, health status, and additional personal characteristics. There is no single treatment for cancer, and patients often receive a combination of therapies and palliative care. Treatments usually fall into one of the following categories: surgery, radiation, chemotherapy, immunotherapy, hormone therapy, or gene therapy.

Surgery
Surgery is the oldest known treatment for cancer. If a cancer has not metastasized, it is possible to completely cure a patient by surgically removing the cancer from the body. This is often seen in the removal of the prostate or a breast or testicle. After the disease has spread, however, it is nearly impossible to remove all of the cancer cells. Surgery may also be instrumental in helping to control symptoms such as bowel obstruction or spinal cord compression.

Radiation
Radiation treatment, also known as radiotherapy, destroys cancer by focusing high-energy rays on the cancer cells. This causes damage to the molecules that make up the cancer cells and leads them to commit suicide. Radiotherapy utilizes high-energy gamma-rays that are emitted from metals such as radium or high-energy x-rays that are created in a special machine. Early radiation treatments caused severe side-effects because the energy beams would damage normal, healthy tissue, but technologies have improved so that beams can be more accurately targeted. Radiotherapy is used as a standalone treatment to shrink a tumor or destroy cancer cells (including those associated with leukemia and lymphoma), and it is also used in combination with other cancer treatments.

Chemotherapy
Chemotherapy utilizes chemicals that interfere with the cell division process - damaging proteins or DNA - so that cancer cells will commit suicide. These treatments target any rapidly dividing cells (not necessarily just cancer cells), but normal cells usually can recover from any chemical-induced damage while cancer cells cannot. Chemotherapy is generally used to treat cancer that has spread or metastasized because the medicines travel throughout the entire body. It is a necessary treatment for some forms of leukemia and lymphoma. Chemotherapy treatment occurs in cycles so the body has time to heal between doses. However, there are still common side effects such as hair loss, nausea, fatigue, and vomiting. Combination therapies often include multiple types of chemotherapy or chemotherapy combined with other treatment options.

Immunotherapy
Immunotherapy aims to get the body's immune system to fight the tumor. Local immunotherapy injects a treatment into an affected area, for example, to cause inflammation that causes a tumor to shrink. Systemic immunotherapy treats the whole body by administering an agent such as the protein interferon alpha that can shrink tumors. Immunotherapy can also be considered non-specific if it improves cancer-fighting abilities by stimulating the entire immune system, and it can be considered targeted if the treatment specifically tells the immune system to destroy cancer cells. These therapies are relatively young, but researchers have had success with treatments that introduce antibodies to the body that inhibit the growth of breast cancer cells. Bone marrow transplantation (hematopoetic stem cell transplantation) can also be considered immunotherapy because the donor's immune cells will often attack the tumor or cancer cells that are present in the host.

Hormone therapy
Several cancers have been linked to some types of hormones, most notably breast and prostate cancer. Hormone therapy is designed to alter hormone production in the body so that cancer cells stop growing or are killed completely. Breast cancer hormone therapies often focus on reducing estrogen levels (a common drug for this is tamoxifen) and prostate cancer hormone therapies often focus on reducing testosterone levels. In addition, some leukemia and lymphoma cases can be treated with the hormone cortisone.

Gene therapy
The goal of gene therapy is to replace damaged genes with ones that work to address a root cause of cancer: damage to DNA. For example, researchers are trying to replace the damaged gene that signals cells to stop dividing (the p53 gene) with a copy of a working gene. Other gene-based therapies focus on further damaging cancer cell DNA to the point where the cell commits suicide. Gene therapy is a very young field and has not yet resulted in any successful treatments.

How can cancer be prevented?
Cancers that are closely linked to certain behaviors are the easiest to prevent. For example, choosing not to smoke tobacco or drink alcohol significantly lower the risk of several types of cancer - most notably lung, throat, mouth, and liver cancer. Even if you are a current tobacco user, quitting can still greatly reduce your chances of getting cancer.

Skin cancer can be prevented by staying in the shade, protecting yourself with a hat and shirt when in the sun, and using sunscreen. Diet is also an important part of cancer prevention since what we eat has been linked to the disease. Physicians recommend diets that are low in fat and rich in fresh fruits and vegetables and whole grains.

Certain vaccinations have been associated with the prevention of some cancers. For example, many women receive a vaccination for the human papillomavirus because of the virus's relationship with cervical cancer. Hepatitis B vaccines prevent the hepatitis B virus, which can cause liver cancer.

Some cancer prevention is based on systematic screening in order to detect small irregularities or tumors as early as possible even if there are no clear symptoms present. Breast self-examination, mammograms, testicular self-examination, and Pap smears are common screening methods for various cancers.

What causes cancer?

Cancer is ultimately the result of cells that uncontrollably grow and do not die. Normal cells in the body follow an orderly path of growth, division, and death. Programmed cell death is called apoptosis, and when this process breaks down, cancer begins to form. Unlike regular cells, cancer cells do not experience programmatic death and instead continue to grow and divide. This leads to a mass of abnormal cells that grows out of control.

What is Cancer?

Cancer is a class of diseases characterized by out-of-control cell growth. There are over 100 different types of cancer, and each is classified by the type of cell that is initially affected.

Cancer harms the body when damaged cells divide uncontrollably to form lumps or masses of tissue called tumors (except in the case of leukemia where cancer prohibits normal blood function by abnormal cell division in the blood stream). Tumors can grow and interfere with the digestive, nervous, and circulatory systems, and they can release hormones that alter body function. Tumors that stay in one spot and demonstrate limited growth are generally considered to be benign.

More dangerous, or malignant, tumors form when two things occur:

a cancerous cell manages to move throughout the body using the blood or lymph systems, destroying healthy tissue in a process called invasion
that cell manages to divide and grow, making new blood vessels to feed itself in a process called angiogenesis.

When a tumor successfully spreads to other parts of the body and grows, invading and destroying other healthy tissues, it is said to have metastasized. This process itself is called metastasis, and the result is a serious condition that is very difficult to treat.

In 2007, cancer claimed the lives of about 7.6 million people in the world. Physicians and researchers who specialize in the study, diagnosis, treatment, and prevention of cancer are called oncologists.

What is HIV Testing?

HIV testing tells you if you are infected with the Human Immunodeficiency Virus (HIV) which causes AIDS. These tests look for "antibodies" to HIV. Antibodies are proteins produced by the immune system to fight a specific germ.

Other "HIV" tests are used when people already know they are infected with HIV. These measure how quickly the virus is multiplying (a viral load test, see Fact Sheet 125) or the health of your immune system (a CD4 count, see Fact Sheet 124).

How Do I Get Tested?

In September 2006, the US Centers for Disease Control recommended routine HIV screening of people in healthcare settings. This should result in more general HIV testing in the US.
You can arrange for HIV testing at any Public Health office, or at your doctor's office. Test results are usually available within two weeks. In the US, call the National AIDS Hotline, (800) 342-2437.

The most common HIV test is a blood test. Newer tests can detect HIV antibodies in mouth fluid (not the same as saliva), a scraping from inside the cheek, or urine. "Rapid" HIV test results are available within 10 to 30 minutes after a sample is taken. One of these tests has produced a high rate of false positives. A positive result on any HIV test should be confirmed with a second test.

Home test kits: You can't test yourself for HIV at home. The "Home Access" test kit is only designed to collect a sample of your blood. You send the sample to a laboratory where it is tested for HIV.

When Should I Get Tested?

If you become infected with HIV, it usually takes between three weeks and two months for your immune system to produce antibodies to HIV. If you think you were exposed to HIV, you should wait for two months before being tested. You can also test right away and then again after two or three months. During this "window period" an antibody test may give a negative result, but you can transmit the virus to others if you are infected.

About 5% of people take longer than two months to produce antibodies. There is one documented case of a person exposed to HIV and hepatitis C at the same time. Antibodies to HIV were not detected until one year after exposure. Testing at 3 and 6 months after possible exposure will detect almost all HIV infections. However, there are no guarantees as to when an individual will produce enough antibodies to be detected by an HIV test. If you have any unexplained symptoms, talk with your health care provider and consider re-testing for HIV.

Do Any Tests Work Sooner After Infection?

Viral load tests detect pieces of HIV genetic material. They show up before the immune system manufactures antibodies. Also, in early 2002, the FDA approved "nucleic acid testing." It is similar to viral load testing. Blood banks use it to screen donated blood.

The viral load or nucleic acid tests are generally not used to see if someone has been infected with HIV because they are much more expensive than an antibody test. They also have a slightly higher error rate.

What Does It Mean if I Test Positive?

A positive test result means that you have HIV antibodies, and are infected with HIV. You will get your test result from a counselor who should tell you what to expect, and where to get health services and emotional support.

Testing positive does not mean that you have AIDS (see Fact Sheet 101, What Is AIDS?). Many people who test positive stay healthy for several years, even if they don't start taking medication right away.

If you test negative and you have not been exposed to HIV for at least three months, you are not infected with HIV. Continue to protect yourself from HIV infection (see Fact Sheet 150, Stopping the Spread of HIV).

Can I Keep the Test Result Confidential?

You can be tested anonymously in many places. You do not have to give your name when you are tested at a public health office, or when you receive the test results. You can be tested anonymously for HIV as many times as you want.

If you get a positive HIV test that is not anonymous, or if you get any medical services for HIV infection, your name may be reported to the Department of Health.

The Centers for Disease Control (CDC) proposed in late 1998 that all states keep track of the names of HIV-infected people. This proposal has not yet taken effect.

How Accurate Are the Tests?

Antibody test results for HIV are accurate more than 99.5% of the time. Before you get the results, the test has usually been done two or more times. The first test is called an "EIA" or "ELISA" test. Before a positive ELISA test result is reported, it is confirmed by another test called a "Western Blot".

Some special cases can give false or unclear results:

Children born to HIV-positive mothers may have false positive test results for several months because mothers pass infection-fighting antibodies to their newborn children. Even if the children are not infected, they have HIV antibodies and will test positive. Other tests, such as a viral load test, must be used.

As mentioned above, people who were recently infected may test negative if they get tested too soon after being infected with HIV.

Pregnant women may have false or unclear test results due to changes in their immune system.

The Bottom Line

HIV testing generally looks for HIV antibodies in the blood, or saliva or urine. The immune system produces these antibodies to fight HIV. It usually takes two to three months for them to show up. In rare cases, it can take longer than three months. During this "window period" you may not test positive for HIV even if you are infected. Normal HIV tests don't work for newborn children of HIV-infected mothers.

In many places, you can get tested anonymously for HIV. Once you test positive and start to receive health care for HIV infection, your name may be reported to the Department of Health. These records are kept confidential.

A positive test result does not mean that you have AIDS. If you test positive, you should learn more about HIV and decide how to take care of your health.

HIV Testing 101

There's only one way to find out for sure whether you have HIV: Get tested. Although some people feel symptoms when they've been newly infected with HIV, most people don't. That's one reason why HIV continues to spread throughout the world: Millions of people are estimated to be living with HIV without even knowing it. That's why it's so important for everybody to get tested regularly for HIV, if they have sex or use injection drugs.

It's completely normal to get nervous, scared or even a little paranoid when you think you've put yourself at risk for HIV. An HIV test -- taken at least six weeks after the risky event -- can answer that question. Approved HIV tests are extremely reliable. There's even a saliva test you can take at many doctor's offices or clinics that will give you results in less than half an hour. (If it comes out positive, you'll need to get an even more reliable blood test, known as a Western Blot, that will confirm the results in a couple of weeks.) And don't forget, if you are at risk for HIV from sex, then you are also at risk for other sexually transmitted diseases that can be much easier to get.

If you live in the United States and are concerned about your privacy, in much of the United States, especially in cities, there are clinics and hospitals where you can be tested for HIV completely anonymously. There are even places that will help you notify past partners if you do test positive for HIV.

What is HIV?

you're new to HIV or already an expert, there is always more to know. In fact, there's so much to learn about HIV that it can seem overwhelming. But that's what we're here for. Use this page as a starting point for learning everything you need to know about HIV.

Let's start with the basics. HIV is short for "human immunodeficiency virus."

How Do You Get HIV?
You can get HIV through unprotected sex or by sharing needles or other equipment used to inject drugs.

Who Gets HIV?
Anybody can get HIV. HIV is a virus; once it gets into your body, it can make you sick. It does so if you are rich or poor; 14 years old or 70; black or white; gay or straight; married or single. It's what you do, not who you are, that puts you at risk for HIV.

How Long Does It Take to Feel a Symptom of HIV?
People can have HIV for 10 years or more and never show any symptoms. Other people can get symptoms within a short time after being infected. The only way you can tell if you have HIV is to get an HIV test.

How Long Will I Live With HIV?
If you keep your CD4 count up, keep your viral load down, take your HIV meds properly and live a healthy life, there's no reason to think that your life will be any shorter with HIV than it would have been without it. The latest information on life expectancy for HIVers shows that HIV-positive people who are on treatment can expect to live well into their 60s and beyond -- and the estimates keep getting closer to those of HIV-negative people as HIV meds become more and more effective.

What Should a Person Do After They Test Positive?
If you've already tested positive for HIV, then there are tests a doctor can do to see whether your HIV is progressing, and whether it's wise to start taking HIV medications.

For most people, if HIV treatment is not started when their doctor recommends it (i.e., when their CD4 count is low or their viral load is high), eventually their immune system will weaken to the point that they may develop life-threatening health problems.

If you're newly diagnosed, it can also be incredibly beneficial if you seek out support, get help from your local HIV organization and connect with other HIV-positive people. Visit our "Just Diagnosed" page to read much more.

Where Did HIV Come From?
The origins of HIV are still a little murky. Experts currently think that, about 100 years ago in Africa, an ancestor of HIV evolved into a form that jumped from monkeys to humans. The history of the global HIV pandemic is more recent, however: The world only began to pay attention to HIV in the early 1980s, when gay men in New York City and San Francisco began to die of a mysterious illness. The term "AIDS" -- which is what doctors call it when HIV disease becomes advanced -- wasn't coined until 1982, and the virus now known as HIV wasn't identified as the cause of AIDS until 1984.

Research Shows HIV Gene Therapy Can Work

Assisted Reproduction Procedures Increasing; Multiple Births Declining