They hoped to find a molecule that could compete with penicillin for the organic acid transporter responsible for excretion, such that the transporter would preferentially excrete the competing molecule and the penicillin would be retained. The uricosuric agent probenecid proved to be suitable. When probenecid and penicillin are administered together, probenecid competitively inhibits the excretion of penicillin, increasing penicillins concentration and prolonging its activity. Eventually, the advent of mass-production techniques and semi-synthetic penicillins resolved the supply issues, so this use of probenecid declined. Probenecid is still useful, however, for certain infections requiring particularly high concentrations of penicillins.After World War II, Australia was the first country to make the drug available for civilian use. In the U.S., penicillin was made available to the general public on March 15, 1945.Fleming, Florey, and Chain shared the 1945 Nobel Prize in Physiology or Medicine for the development of penicillin. Structure determination and total synthesis
The chemical structure of penicillin was first proposed by Edward Abraham in 1942 and was later confirmed in 1945 using X-ray crystallography by Dorothy Crowfoot Hodgkin, who was also working at Oxford. She later in 1964 received the Nobel Prize for Chemistry for this and other structure determinations. Chemist John C. Sheehan at the Massachusetts Institute of Technology (MIT) completed the first chemical synthesis of penicillin in 1957. Sheehan had started his studies into penicillin synthesis in 1948, and during these investigations developed new methods for the synthesis of peptides, as well as new protecting groups—groups that mask the reactivity of certain functional groups.
Mansonelliasis  is the condition of infection by the nematode Mansonella. The disease exists in Africa and tropical Americas, spread by biting midges or blackflies. It is usually asymptomatic. Symptoms and signs
Infections by Mansonella perstans, while often asymptomatic, can be associated with angioedema, pruritus, fever, headaches, arthralgias, and neurologic manifestations. Mansonella streptocerca can manifest on the skin via pruritus, papular eruptions and pigmentation changes. Mansonella ozzardi can cause symptoms that include arthralgias, headaches, fever, pulmonary symptoms, adenopathy, hepatomegaly, and pruritus. Eosinophilia is often prominent but do not occur in all cases of Mansonelliasis. M. perstans can also present with Calabar-like swellings, hives, and a condition known as Kampala, or Ugandan eye worm. This occurs when adult M. perstans invades the conjunctiva or periorbital connective tissues in the eye. M. perstans can also present with hydrocele in South America. However, it is often hard to distinguish between the symptoms of Mansonelliasis and other nematode infections endemic to the same areas. Causes
Mansonelliasis is caused by nematodes (roundworms) in the Mansonella genus that reside in the skin or certain body cavities. The specific species are M. perstans, M. streptocerca and M. ozzardi. Vectors and life cycle
During a blood meal, an infected midge (genus Culicoides) or blackfly (genus Simulium) introduces third-stage filarial larvae onto the skin of the human host, where they penetrate into the bite wound.