Factor VIII (FVIII) is an essential blood-clotting protein, also known as anti-hemophilic factor (AHF). In humans, factor VIII is encoded by the F8 gene. Defects in this gene result in hemophilia A, a recessive X-linked coagulation disorder. Factor VIII is produced in liver sinusoidal cells and endothelial cells outside the liver throughout the body. This protein circulates in the bloodstream in an inactive form, bound to another molecule called von Willebrand factor, until an injury that damages blood vessels occurs. In response to injury, coagulation factor VIII is activated and separates from von Willebrand factor. The active protein (sometimes written as coagulation factor VIIIa) interacts with another coagulation factor called factor IX. This interaction sets off a chain of additional chemical reactions that form a blood clot.Factor VIII participates in blood coagulation; it is a cofactor for factor IXa, which, in the presence of Ca2+ and phospholipids, forms a complex that converts factor X to the activated form Xa. The factor VIII gene produces two alternatively spliced transcripts. Transcript variant 1 encodes a large glycoprotein, isoform a, which circulates in plasma and associates with von Willebrand factor in a noncovalent complex. This protein undergoes multiple cleavage events. Transcript variant 2 encodes a putative small protein, isoform b, which consists primarily of the phospholipid binding domain of factor VIIIc. This binding domain is essential for coagulant activity.People with high levels of factor VIII are at increased risk for deep vein thrombosis and pulmonary embolism.
The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) mentions paruresis by name.Kaplan & Sadocks Synopsis of Psychiatry states, "Persons with social phobias (also called social anxiety disorder) have excessive fears of humiliation or embarrassment in various social settings, such as in speaking in public, urinating in a public rest room (also called shy bladder), and speaking to a date." The Synopsis describes shy bladder as "inability to void in a public bathroom" and notes that relaxation exercises are an application of behavior therapy for dealing with this disorder. Some paruretics experience delayed urination and must wait for their need to void to overcome their anxiety, while others are unable to urinate at all. Treatment
In terms of treating the mental aspect of paruresis, such treatment can be achieved by graduated exposure therapy and cognitive behavioral therapy. In graduated exposure therapy, the subject has a trusted person stand outside the restroom at first, and once the fear is overcome the observer is brought closer in, until step by step the phobia is vanquished. The International Paruresis Association provides a detailed discussion of this method on its website. In addition to gradual exposure therapy, cognitive behavioral therapy is used to change a patients mental approach to the condition, from one of a person who cannot urinate, to a person who can urinate or is not overly fearful when they cant publicly urinate.