The more selective transport of proline and other imino acids is driven at the molecular level by a mammalian cellular transport mechanism aptly known as system IMINO. While no single genetic mutation has been established as the cause of iminoglycinuria; several mutations, affecting transport mechanisms shared by glycine, proline and hydroxyproline, as well as those that selectively transport either glycine or imino acids, including the IMINO system, are known to be associated with the disorder. When combined, these factors will result in a variable phenotype for iminoglycinuria depending on which mutations are present. However, despite the role that intestinal malabsorption of glycine and imino acids can play in iminoglycinuria, the primary defect disrupts their renal transport and reabsorption. This is evident, as inherited iminoglycinuria can be clinically present with no intestinal involvement.In mammals, including humans, the transport of amino and imino acids from the lumen (interior) of the intestine or the renal proximal tubule into the cells occurs at the brush border membrane of the epithelium (moist, tightly packed cellular lining of many tissues and organs of the body). Here, cotransporters such as sodium or chloride (part of the system of Na-K-Cl cotransporters) couple with the amino or imino acids on the molecular level and transport them through specific integral membrane proteins that form ion channels, which are located within the cell membrane. From the cells, the absorbed or reabsorbed amino and imino acids eventually reach the blood.
Treatment
In a hypertensive emergency, treatment should first be to stabilize the patients airway, breathing, and circulation per ACLS guidelines. Patients should have their blood pressure slowly lowered over a period of minutes to hours with an antihypertensive agent. Documented goals for blood pressure include a reduction in the mean arterial pressure by less than or equal to 25% within the first 8 hours of emergency. If blood pressure is lowered aggressively, patients are at increased risk of complications including stroke, blindness, or kidney failure. Several classes of anti hypertensive agents are recommended, with the choice depending on the cause of the hypertensive crisis, the severity of the elevation in blood pressure, and the patients baseline blood pressure prior to a hypertensive emergency. Physicians will attempt to identify a cause of the patients hypertension, including chest radiograph, serum laboratory studies evaluating kidney function, urinalysis, as that will alter the treatment approach for a more patient-directed regimen.Hypertensive emergencies differ from hypertensive urgency in that they are treated parenterally, whereas in urgency it is recommended to use oral anti hypertensives to reduce the risk of hypotensive complications or ischemia. Parenteral agents are classified into beta-blockers, calcium channel blockers, systemic vasodilators, or other (fenoldopam, phentolamine, clonidine). Medications include labetalol, nicardipine, hydralazine, sodium nitroprusside, esmolol, nifedipine, minoxidil, isradipine, clonidine, and chlorpromazine. These medications work through a variety of mechanisms. Labetalol is a beta-blocker with mild alpha antagonism, decreasing the ability of catecholamine activity to increase systemic vascular resistance, while also decreasing heart rate and myocardial oxygen demand.