[Progesteron--an old--new option in the prevention of preterm birth]

Controlled-release systems for intravaginal and intrauterine drug delivery have been developed primarily for the administration of contraceptive steroid hormones. These delivery routes circumvent first-pass hepatic metabolism, thereby enhancing bioavailability and allowing for reduced systemic dosages compared to oral administration. Such approaches contribute to improved therapeutic efficacy and patient compliance, particularly in long-term contraceptive regimens.Intravaginal Drug Delivery...

Vasectomy is a surgical form of male sterilization that involves severing and sealing the vasa deferentia, preventing sperm from mixing with semen during ejaculation. Because a vasectomy does not impact the testes' ability to produce testosterone, hormone levels, libido, and sexual function generally remain unchanged. While vasectomy is highly effective in preventing pregnancy, with a success rate near 99.85%, rare cases of recanalization (spontaneous reconnection) can occur. Although vasectomy...

The gastric mucosa produces prostaglandins E2 (PGE2) and prostacyclin (PGI2), crucial in maintaining gastric health. They exert cytoprotective effects, including increasing bicarbonate secretion, releasing protective mucin, reducing gastric acid output, and preventing harmful vasoconstriction. These effects are mediated through various receptors, such as EP1, EP2, EP3, and EP4.
Non-steroidal anti-inflammatory drugs (NSAIDs) can induce peptic ulcers by inhibiting cyclooxygenase, decreasing...

Third-generation β-blockers, such as labetalol and carvedilol, represent a significant advancement in managing cardiovascular conditions. Unlike conventional β-blockers, which can induce peripheral vasoconstriction, third-generation drugs block α1 adrenoceptors. This promotes vasodilation through several mechanisms, such as increased nitric oxide production, inhibition of calcium ion entry, opening of potassium ion channels, and antioxidant action. Labetalol, for instance, is clinically...

Prostacyclin receptor agonists are a class of therapeutic agents integral to managing pulmonary arterial hypertension (PAH). These drugs operate by mimicking the action of prostaglandin I2, or PGI2, a naturally occurring compound in the body.
These agonists bind to the IPR receptor situated on the plasma membrane of the pulmonary artery smooth muscle cells. This binding triggers a cascade of reactions known as the GS-AC-cAMP-PKA pathway. This pathway results in the relaxation of smooth muscle...

The ovarian cycle is meticulously regulated by the hypothalamic-pituitary-gonadal axis. This cycle orchestrates the release of a mature oocyte, essential for reproduction.
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle.  At puberty, GnRH secretion increases in both frequency and...