Proposed mechanism
The mechanism of progesterone protective effects may be the reduction of inflammation that follows brain trauma and hemorrhage.Damage incurred by traumatic brain injury is believed to be caused in part by mass depolarization leading to excitotoxicity. One way in which progesterone helps to alleviate some of this excitotoxicity is by blocking the voltage-dependent calcium channels that trigger neurotransmitter release. It does so by manipulating the signaling pathways of transcription factors involved in this release. Another method for reducing the excitotoxicity is by up-regulating the GABAA, a widespread inhibitory neurotransmitter receptor.Progesterone has also been shown to prevent apoptosis in neurons, a common consequence of brain injury. It does so by inhibiting enzymes involved in the apoptosis pathway specifically concerning the mitochondria, such as activated caspase 3 and cytochrome c.
Not only does progesterone help prevent further damage, it has also been shown to aid in neuroregeneration. One of the serious effects of traumatic brain injury includes edema. Animal studies show that progesterone treatment leads to a decrease in edema levels by increasing the concentration of macrophages and microglia sent to the injured tissue. This was observed in the form of reduced leakage from the blood brain barrier in secondary recovery in progesterone treated rats. In addition, progesterone was observed to have antioxidant properties, reducing the concentration of oxygen free radicals faster than without. There is also evidence that the addition of progesterone can also help remyelinate damaged axons due to trauma, restoring some lost neural signal conduction.
A placental site nodule (PSN) is benign remnant from a previous pregnancy. Presentation
They are typically asymptomatic and found incidentally. Pathology
PSNs are intermediate trophoblastic remnants. Diagnosis
PSN are diagnosed by examining the tissue under a microscope, usually obtained with a dilation and curettage. Typically, they consist of pink (hyaline) material using the standard stain and contain few cells. Bizarre multinucleated cells may be present; however, there is no mitotic activity. The differential diagnosis includes (cervical) squamous cell carcinoma, gestational trophoblastic disease, and exaggerated placental site. Prognosis
PSN are benign. Once removed, they do not require any treatment and do not recur. See also
Gestational trophoblastic disease
Placental site trophoblastic tumour

References


== External links ==