Filter by Topic
Filter by Format
Dennis Lo, also called Yuk Ming Dennis Lo, is a
professor at the Chinese University of Hong Kong in Hong Kong,
China. In 1997, Lo discovered fetal DNA in maternal
plasma, which is the liquid component of a pregnant woman's
blood. By 2002, Lo distinguished the DNA differences between pregnant women
and their fetuses, enabling scientists to identify fetal DNA in pregnant
women's blood. Lo used his discoveries to develop several
non-invasive and prenatal genetic tests, including tests for blood
Margaret Higgins Sanger advocated for birth control in the United States and Europe during the late nineteenth and early twentieth centuries. Although people used contraceptives prior to the twentieth century, in the US the 1873 Comstock Act made the distribution of information relating to the use of contraceptives illegal, and similar state-level Comstock laws also classified discussion and dissemination of contraceptives as illegal.
Max Ludwig Henning Delbrick applied his knowledge of theoretical physics to biological systems such as bacterial viruses called bacteriophages, or phages, and gene replication during the twentieth century in Germany and the US. Delbrück demonstrated that bacteria undergo random genetic mutations to resist phage infections. Those findings linked bacterial genetics to the genetics of higher organisms. In the mid-twentieth century, Delbrück helped start the Phage Group and Phage Course in the US, which further organized phage research.
Eugen Steinach researched sex hormones and their effects on mammals in the late nineteenth and early twentieth centuries in Europe. He experimented on rats by removing their testicles and implanting them elsewhere in their bodies, and he found that the testes interstitial cells produce male sex hormones. He developed the Steinach Rejuvenation Procedure, which he claimed could rejuvenate men by increasing their production of sex hormones. Steinach’s work on female sex hormones and on ovarian extracts led to the development of the first standardized injectable estrogen.
Harald zur Hausen studied viruses and discovered that certain strains of the human papilloma virus (HPV), a sexually transmitted disease, can cause cervical cancer, in Europe during the twentieth and twenty-first centuries. Zur Hausen spent his research career identifying the viruses that cause diseases, particularly cancer-causing viruses (oncoviruses). He primarily focused on HPV and cervical cancer. Zur Hausen hypothesized that HPV was cancerous and discovered that two strains, HPV 16 and 18, caused cervical cancer.