The genome of the organism that produces the world's most lethal toxin has been revealed. This toxin is the major weapon in the genome of Clostridium botulinum: less than two kg is enough to kill every person on the planet.
Tension pneumothorax: The most serious type of pneumothorax, this occurs when the pressure in the pleural space is greater than the atmospheric pressure, either because air becomes trapped in the pleural space or because the entering air is from a positive-pressure mechanical ventilator.
In these cases, the pneumothorax occurs because the diseased lung tissue is next to the pleural space. Secondary spontaneous pneumothorax can be more severe and even life-threatening because diseased tissue may open a wider hole, allowing more air into the pleural space than does a small, ruptured bleb.