The first sign of syphilis usually appears 2 to 10 weeks following exposure. A red, oval sore, called a chancre (pronounced shanker) develops at the site where the bacteria entered the body. The lesion typically looks clean, is not pus filled, and is often painless.

Apoptase is not an enzyme identified with a role in HIV infection.

Gonococci and the elementary body form of chlamydia enter the body by attaching to nonciliated columnar epithelial cells. Remember that infection by gonococci leads to LPS-mediated cytotoxic events on adjacent cells, causing surface damage and allowing for easier access to infection by other organisms such as chlamydia.

Histamine upregulates P-selectin of vascular endothelium.

Bacteria opsonized by IgG and C3b will adhere and activate both macrophages and neutrophils for phagocytosis and killing.

There are receptors for C3b on the surface of phagocytic cells.

Parasites like Trichinella frequently increase the IgE levels, usually polyclonally. This tends to inhibit the protective effect of IgE by diluting out the specific IgE on the mast cell. Inflammation induced by mast cell degranulation leads to influx of IgG which causes damage to the parasite.

The superantigens combine with the framework regions of certain TCR V beta families irrespective of their complementarity determining regions.

The membrane attack complex containing C8 and C9 is important for destroying the Neisseria bacterium.

In 1909, Richard Richter developed the first intrauterine device made from silkworm gut.

The 26^th of September is World Contraception Day, devoted to raising awareness and improving education about sexual and reproductive health, with a vision of a world where every pregnancy is wanted.

An intrauterine device (IUD or coil)[1] is a small contraceptive device, often 'T'-shaped. It contains either copper or levonorgestrel, which is inserted into the uterus.

The latent phase of infection is an asymptomatic period between the secondary and tertiary stages of disease which can last from months to years.

Trestolone is an anabolic steroid that has been shown to significantly reduce sperm count.

Gonococci develop resistance to antibiotics through plasma-mediated mechanisms, most leading to resistance to penicillin and tetracycline.