In research published last year, Burk and colleagues analyzed the genetic sequences of HPV16 viruses from thousands of individuals and found that few women shared an identical form of the virus. The researchers isolated papillomaviruses from the oral, perianal and genital areas of squirrel and rhesus monkeys.
When the scientists then compared the virus genomes, they found that the viruses that were most similar to each other came from the same parts of the body, meaning before papillomaviruses took up residence as cancer-causing parasites in humans, they first adapted to particular places in the body. The viruses then evolved within these niches for at least 40 million years. To find out how the highly pathogenic HPV16 type of the virus evolved, the team then compared more than complete HPV16 virus genomes and over 3, partial sequences isolated from around the world.
The timing coincides with a split in Neanderthal populations that spread through Eurasia around thousand years ago. Register or Log In. The Magazine Shop. He remained there until when he moved to continue his education at the University of Hamburg in Hamburg, Germany. In , he graduated from the Medical Academy with his medical degree. Zur Hausen then spent two years working as a medical intern to receive a license to practice medicine in Germany.
He worked in surgery and internal medicine, but spent most of his time as an intern in obstetrics and gynecology. After his medical internship, zur Hausen pursued a career in research rather than as a physician.
Zur Hausen received basic research training in the fields of bacteriology and virology through his study of the effects of the vaccinia virus in mouse cells. Zur Hausen found that the virus caused mutations in cells' chromosomes, the structures that carry DNA, but he couldn't explain why they caused those mutations.
Zur Hausen later said that he had limited resources for furthering his research education because studying bacteria and viruses was just beginning in Germany during the s.
While zur Hausen searched for research opportunities, he married his first wife in , and they had a son, Jan Dirk, a year later. In , Zur Hausen became a post-doctoral researcher in the United States. It can cause several diseases, including mononucleosis, an infection characterized by fever, sore throat, and fatigue. In the s, though, scientists had recently discovered the virus in Burkitt's lymphoma cells. Burkitt's lymphoma is a cancer of the fluid that contains white blood cells lymph.
The Henles and their research team were working to develop diagnostic tests for EBV using blood samples serological tests in addition to determining if EBV caused Burkitt's lymphoma. The research team hypothesized that EBV acted as an oncovirus, or a virus that causes cancer, by maintaining a persistent infection in the lymphatic cells. A persistent virus infection means that the virus has inserted itself into the cell and remains there for a long time. Viruses in a cell replicate there and then infect other cells.
The Henles hypothesized that EBV lingered in some lymphatic cells, slowly transferring the virus to other cells. While zur Hausen expressed interest in studying EBV, he had little experience with the required research procedures. Zur Hausen worked with a different virus, the adenovirus, to familiarize himself with lab procedures. The adenovirus most commonly causes respiratory illness, though it can also lead to infections of the bladder or digestive system.
The Henles taught zur Hausen how to use a method, nucleic acid hybridization, to identify and analyze DNA, as well as how to use other methods to detect viral DNA in sample cells. Using those methods, zur Hausen looked for chromosome mutations in human cells infected with the adenovirus. He also analyzed chromosomal differences in human lymphoblastoids, which are immature cells that eventually become different types of white blood cells.
While still working on his research with the adenovirus, zur Hausen began researching EBV. He analyzed Burkitt's lymphoma cells using an electron microscope , which bounces electrons off a specimen to create a high quality image of that specimen. When he did so, he discovered EBV in the cancerous cells. Zur Hausen's analysis further supported the hypothesis that EBV played a significant role in Burkitt's lymphoma.
Zur Hausen's second son, Axel, was born in He led an independent lab group and continued to research EBV. Zur Hausen proposed the virus only became activated in certain cells. Further research confirmed these findings and actually proved that the initial figure was underestimated.
In , a group of scientists undertook a rigorous study in which they re-tested the samples. They found that HPV was present in virtually all cervical cancers Though scientists have identified over a hundred types of HPV, there are only 13 high-risk types linked to cancer.
Additionally, scientists discovered that genital warts are caused by different types of HPV than the high-risk, cancer-causing strains. Fortunately, most women infected with high-risk HPV will not develop cervical cancer. With current testing and treatment options , those who do develop cancer have a better chance of survival. Start Here. Expert Advice. A Surprising Connection In the s, scientists searching for possible causes of cervical cancer began looking into lifestyle factors which may be linked to the disease.
Harold zur Hausen courtesy of Nobelprize. Human papillomavirus types 6 and 11 DNA sequences in genital and laryngeal papillomas and in some cervical cancers : National Center for Biotechnology Information,
0コメント