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P Y Fan

Publications and source records attributed to P Y Fan.

11 recordsLinked to original sources
PubMed1999

A novel united network for organ sharing region kidney allocation plan improves transplant access for minority candidates.

BACKGROUND: We report the consequences of a novel kidney allocation system on access of non-Caucasians (NC) to kidney transplantation. This new plan has provided a balance of allocation determinants between time waiting, HLA match, and geography (population density between donor and recipient center). METHODS: Three sequential systems of regional allocation were analyzed: period I (September 1994 to September 1996), period II (September 1996 to November 1997), and period III (December 1997 to March 1 1999). Periods II and III are reflective of the new allocation plan. RESULTS: During periods II and III, the NC rate of kidney transplantation increased closer to the NC proportion on the wait list, comparatively exceeding the national UNOS data. There was no statistical difference in regional mean wait time between Caucasian and NC. Improvements in access to transplantation for NCs between period I and periods II and III appear to be related to changes in geographic allocation weight from local unit to population density points, to the inclusion of the entire region in the plan, and to the deletion of intermediate degrees of B/DR mismatching in the revised plan. Despite the increased proportion of NCs on the wait list from period I to period III, the percentage difference between the proportion of NCs waiting on the list and the proportion NCs receiving a transplant fell from 7.8% to 4.9%. CONCLUSIONS: These data demonstrate that this new allocation plan was associated with improved access of minority candidates to transplantation. The broadening of geographic allocation and the alteration of HLA points appear to permit a more favorable opportunity for renal transplantation to NC candidates. selection, compared to the UNOS formula. In this report, we analyze the consequences of the Region 1 allocation system on the access of non-Caucasian (NC) candidates to cadaver donor kidney transplantation.

Health Services Accessibility↗
PubMed1995

The effects of short-term treatment with the prostaglandin E1 (PGE1) analog misoprostol on inflammatory mediator production in murine lupus nephritis.

MRL-lpr/lpr mice spontaneously develop an autoimmune disease with nephritis similar to human systemic lupus erythematosus. In these animals, treatment with E-series prostaglandins ameliorates renal disease and prolongs survival, perhaps by modulating production of cytokines or eicosanoids. To further define the mechanisms of action of E-series prostaglandins in established murine lupus nephritis, we administered the prostaglandin E1 (PGE1) analog misoprostol to 20-week-old MRL-lpr/lpr mice by twice-daily subcutaneous injection. After 2 days of treatment, misoprostol reduced renal cortical interleukin-1 beta (IL-1 beta) mRNA levels compared to vehicle-treated controls (0.19 +/- 0.06 (misoprostol) vs 0.50 +/- 0.04 (vehicle) densitometry units; P < 0.005). A similar reduction in cortical IL-1 beta mRNA levels was found in left kidneys harvested from MRL-lpr/lpr mice following 2 days of treatment with misoprostol compared to right kidneys harvested from the same animal prior to the first dose of PGE1 analog (0.12 +/- .05 (left) vs 0.39 +/- 0.18 (right) densitometry units; P < 0.05). This reduction in cortical IL-1 beta mRNA levels was not associated with alterations in renal production of thromboxane B2, PGE2, or leukotriene B4 or with significant changes in the severity of renal inflammatory cell infiltrates. Time-course studies indicated that IL-1 beta mRNA levels were decreased within 24 hr of initiating misoprostol therapy. This reduction in IL-1 beta mRNA levels was transient because levels were not reduced after 1 week of treatment with the PGE1 analog.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Acute vascular access: new advances.

Dual lumen central venous hemodialysis catheters have become the preferred form of acute of acute vascular access. Although they provide rapid angioaccess, these catheters are associated with a number of serious insertion complications. Furthermore, prolonged use can lead to late complications including infection and central venous stenosis. Recent advances in catheter construction as well as new techniques for line placement should reduce the incidence and severity of catheter-related problems.

Catheterization↗
PubMed1993

The azaspirane SKF 105685 ameliorates renal allograft rejection in rats.

The azaspirane SKF 105685 (N,N-dimethyl-8, 8-dipropyl-2-azaspiro (4.5) decane-2-propanamine dihydrochloride) has been shown to attenuate or reverse the course of immunologic disease in several animal models, possibly through the induction of nonspecific suppressor activity. To investigate its effects on immune-mediated renal disease, SKF 105685 was administered by gavage to rats with kidney allografts. Six days after transplantation, GFR (inulin clearance, 1.46 +/- 0.27 versus 0.41 +/- 0.15 mL/min per kg; P < 0.005) and RPF (p-aminohippurate clearance, 5.48 +/- 0.98 versus 1.99 +/- 0.72 mL/min per kg; P < 0.01) were significantly higher in SKF 105685-treated rats compared with vehicle-treated control rats. In addition, mononuclear inflammatory cell infiltrates were significantly reduced in SKF 105685-treated animals compared with controls. Treatment also reduced renal production of thromboxane B2 (81 +/- 22 versus 424 +/- 76 pg/min per mg of protein; P < 0.0005), prostaglandin E2 (612 +/- 165 versus 2,059 +/- 351 pg/min per mg of protein; P < 0.005), and 6-keto prostaglandin F1 alpha (217 +/- 56 versus 943 +/- 186 pg/min per mg of protein; P < 0.005), but interleukin-1 beta mRNA levels within kidney allografts were not affected by treatment. Thus, the azaspirane SKF 105685 is a novel immunosuppressive agent that substantially ameliorates renal allograft rejection in the rat. Although the mechanism of action is unknown, the beneficial effects of SKF 105685 in rejection may relate to its ability to induce suppressor activity and/or its effects on eicosanoid production.

Animals↗
PubMed1992

Identification of a regulated Na/K/Cl cotransport system in a distal nephron cell line.

Lack of an adequate cell model has limited investigation of Na/K/Cl cotransporter regulation in the kidney. Using A6 cells, an amphibian distal renal cell line, we observed that 63% of rubidium uptake in confluent A6 monolayers was ouabain-insensitive. Ouabain-insensitive rubidium uptake was inhibited in a dose-dependent fashion by furosemide (IC50 6.6 microM) or bumetanide (IC50 1.7 microM). Kinetic studies confirmed that furosemide-sensitive rubidium uptake had features consistent with cotransporter activity in other cell lines. Furthermore, specific binding of [3H]bumetanide occurred with a capacity of 8.6 pmol/mg protein and a Kd of 1.6 microM bumetanide. Finally, furosemide-sensitive rubidium uptake was rapidly regulated by a calcium ionophore, the phorbol ester PDBu, forskolin, and adenosine. These data demonstrate an Na/K/Cl cotransport system in the A6 cell which will serve as a useful model for studying cotransporter regulation by endogenous signaling pathways.

Animals↗
PubMed1992

Thromboxane receptor blockade reduces renal injury in murine lupus nephritis.

To investigate the role of thromboxane A2 (TxA2) in murine lupus, we assessed the effects of the specific thromboxane receptor antagonist GR32191 on immune complex glomerulonephritis in MRL-lpr/lpr mice. Forty mg/kg/day GR32191 was given by twice daily subcutaneous injection for eight weeks beginning at 12 weeks of age. This dose completely blocked the renal vasoconstriction produced by the thromboxane agonist U46619. After eight weeks of treatment, both glomerular filtration rate (GFR) (8.9 +/- 0.6 vs. 6.8 +/- 1.1 ml/min/kg; P less than 0.05) and PAH clearance (CPAH) (37.4 +/- 2.5 vs. 29.9 +/- 3.3 ml/min/kg; P less than 0.05) were significantly higher in mice given GR32191 compared to vehicle treated animals. Administration of GR32191 also reduced proteinuria from 18.1 +/- 11.6 to 3.7 +/- 1.3 mg/24 hours (P less than 0.05). In GR32191 treated MRL-lpr/lpr mice, renal hemodynamic function and proteinuria were not significantly different from congenic MRL-+/+ controls. Thromboxane receptor blockade had striking affects on renal histomorphology reducing both hyaline thrombi in glomeruli (P = 0.022) and interstitial inflammation (P = 0.006). Glomerular crescents and severity of vasculitis also tended to be reduced in mice receiving the thromboxane receptor antagonist. The overall histopathologic score in mice given GR32191 was significantly lower than vehicle treated animals (4.7 +/- 0.5 vs. 8.4 +/- 1.5; P = 0.016). These effects of GR32191 were associated with decreased excretion of thromboxane B2 (TxB2) in urine (292 +/- 37 vs. 747 +/- 155 pg/24 hr; P less than 0.005) as well as a modest reduction in glomerular deposits of IgG (semiquantitative score 2.6 +/- 0.2 vs. 3.5 +/- 0.2; P less than 0.02). Thus, chronic thromboxane receptor blockade markedly altered the course of renal disease in MRL-lpr/lpr mice, suggesting that TxA2 is an important mediator of renal dysfunction and injury in this murine model of lupus nephritis.

Animals↗
PubMed1992

Vascular access: concepts for the 1990s.

Modern hemodialysis requires repeated reliable access to blood vessels capable of providing rapid extracorporeal blood flow. This necessity for reliable access to the circulation is the Achilles' heel of modern hemodialysis. Native and synthetic arteriovenous fistulas remain the preferred method of maintaining long-term hemodialysis access. Vascular access dysfunctions (thrombosis and infection) are the most common complications encountered in the care of end-stage renal disease patients. This article focuses on the mechanisms by which permanent vascular access for hemodialysis is obtained and deals with the common complications that result. This review will evaluate these common complications and outline new methods for improving vascular access patency. New concepts focusing on the prospective detection and correction of venous stenoses as well as on the prevention of other factors that predispose to access failure are explored.

Angioplasty, Balloon↗