Seminars in nephrology
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The hepatorenal syndrome is defined as functional renal failure in advanced chronic or acute liver disease with portal hypertension. Morphologic abnormalities of the kidneys are frequently absent and tubular function is preserved. Patients with the hepatorenal syndrome are characterized by progressive splanchnic and systemic vasodilation and decreased effective arterial blood volume. ⋯ Orthotopic liver transplantation is the best current treatment and leads to a gradual recovery of renal function in the vast majority of patients. Because mortality of type I hepatorenal syndrome is excessive, supportive treatment by vasoconstrictor drugs, transjugular intrahepatic portosystemic shunt, and renal replacement therapy has been investigated to achieve stability until transplantation. The definite role of these promising developments, however, is still uncertain, emphasizing the need for large prospective multicentric investigations.
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Percutaneous placement of cuffed tunneled catheters for hemodialysis access has become a firmly established method of providing vascular access to patients with end-stage renal disease. Considerable evidence supports the right internal jugular vein as the preferred site for catheter insertion. The use of real-time imaging using both ultrasound and fluoroscopy permits simple, safe, and effective placement of the catheter for hemodialysis. ⋯ A specific method of placement is described including variations for specific catheter types. The new subcutaneous port as an alternative to the cuffed tunneled catheter appears to provide another option for vascular access; preliminary data suggests higher flow rates and lower infection rates compared with externalized cuffed tunneled catheters. Finally, the criteria for obtaining training and proficiency in placement of cuffed tunneled catheters are outlined.
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Seminars in nephrology · Jul 2001
Factors influencing access to cardiovascular procedures in patients with chronic kidney disease: race, sex, and insurance.
Blacks and women are less likely to undergo invasive cardiac procedures than whites and men in patients with chronic renal disease. We determined the relationship between ethnic and sex differences in access to cardiac procedures as patients progress to ESRD and acquire Medicare insurance. We performed a cohort study of a nationwide random sample of 4,987 patients who progressed to ESRD in 1986 to 1987 and were followed up for 7 years was used. ⋯ The wide pre-ESRD disparities in cardiac procedure use between white women, black men, and black women compared with white men narrowed substantially with acquisition of Medicare and entry into comprehensive dialysis care. Health insurance contributed to the narrowing of differences. Procedure use for black men still lagged behind the other groups, suggesting the need for closer examination of health needs in this potentially vulnerable group.
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The discovery of aquaporin-1 (AQP1) by Agre and associates answered the longstanding biophysical question of how water specifically crosses biological membranes. In the kidney at least 7 aquaporins are expressed at distinct sites. AQP1 is extremely abundant in the proximal tubule and descending thin limb and is essential for urinary concentration. ⋯ Lack of functional AQP2 is seen in primary forms of diabetes insipidus, and reduced expression and targeting is seen in several diseases associated with urinary concentrating defects such as acquired nephrogenic diabetes insipidus, postobstructive polyuria, as well as acute and chronic renal failure. In contrast, in conditions with water retention such as severe congestive heart failure, pregnancy and SIADH both AQP2 expression levels and apical plasma membrane targetting is increased suggesting a role for AQP2 in the development of water retention. Continued analysis of the aquaporins is providing detailed molecular insight into the fundamental physiology and pathophysiology of water balance and water balance disorders.
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Pancreas transplantation is being performed with increasing frequency and increasing technical success. The availability of new immunosuppressant agents has been associated with a reduction in the previously high rates of allograft rejection in recipients of simultaneous pancreas-kidney transplants. These lower rejection rates have, in turn, led to changes in surgical techniques and a resurgence of interest in isolated pancreas transplantation--either in nonuremic patients or, more commonly, in patients who have already received a prior kidney transplant. Pancreas transplantation has emerged as an important option for the management of patients with type I diabetes mellitus and diabetic nephropathy.