Internists, Nephrologist (kidney)
28 years of experience

Accepting new patients
East Dallas
Dallas Nephrology Assoc
3601 Swiss Ave
Dallas, TX 75204
214-358-2300
Locations and availability (2)

Education ?

Medical School Score
The University of Texas at San Antonio (1982)
  • Currently 2 of 4 apples

Awards & Distinctions ?

Awards  
Castle Connolly's Top Doctors™ (2012 - 2013)
Castle Connolly Top Doctors: Texas™ (2009)
Associations
American Board of Internal Medicine

Affiliations ?

Dr. Melton is affiliated with 12 hospitals.

Hospital Affilations

Score

Rankings

  • Baylor Medical Center At Irving *
    1901 N MacArthur Blvd, Irving, TX 75061
    • Currently 4 of 4 crosses
    Top 25%
  • Baylor University Medical Center
    3500 Gaston Ave, Dallas, TX 75246
    • Currently 4 of 4 crosses
    Top 25%
  • Baylor All Saints Medical Centers
    1400 8th Ave, Fort Worth, TX 76104
    • Currently 4 of 4 crosses
    Top 25%
  • Baylor Regional Medical Center At Grapevine
    1650 W College St, Grapevine, TX 76051
    • Currently 4 of 4 crosses
    Top 25%
  • Methodist Medical Center
    1441 N Beckley Ave, Dallas, TX 75203
    • Currently 3 of 4 crosses
    Top 50%
  • North Central Medical Center
    4500 Medical Center Dr, McKinney, TX 75069
    • Currently 3 of 4 crosses
    Top 50%
  • Baylor Medical Center at Southwest Fort Worth
    1400 8th Ave, Fort Worth, TX 76104
    • Currently 3 of 4 crosses
    Top 50%
  • Baylor Specialty Hospital
    3504 Swiss Ave, Dallas, TX 75204
    • Currently 1 of 4 crosses
  • Baylor All Saints
  • Out of State Hospital
  • Methodist Dallas Medical Center
  • Medical Director of Kidney/Pancreas Transplant
  • * This information was reported to Vitals by the doctor or doctor's office.

    Publications & Research

    Dr. Melton has contributed to 23 publications.
    Title Disseminated Adenovirus Infection in Renal Transplant Recipients: the Role of Cidofovir and Intravenous Immunoglobulin.
    Date September 2010
    Journal Transplant Infectious Disease : an Official Journal of the Transplantation Society
    Excerpt

    Disseminated adenovirus (ADV) infection in solid organ transplant patients is associated with high mortality. Limited studies have shown benefit from using cidofovir (CDV), as well as intravenous immunoglobulin (IVIG). In this study, we report 2 renal transplant patients who presented with fever and pulmonary infiltrates. Both patients continued to worsen despite antibiotic therapy. Bronchoalveolar lavage viral culture and serum polymerase chain reaction (PCR) were positive for ADV. Patients were treated with CDV, IVIG, and reduction in immunosuppression. A progressive decline in serum ADV DNA by PCR correlated with clinical improvement and pulmonary infiltrates improved. Both patients recovered. Allograft function was preserved although reversible acute kidney injury was observed in both patients. To the best of our knowledge, this is the first successful use of CDV and IVIG in renal transplant patients with disseminated ADV infection.

    Title Predicting Renal Failure After Liver Transplantation from Measured Glomerular Filtration Rate: Review of Up to 15 Years of Follow-up.
    Date February 2010
    Journal Transplantation
    Excerpt

    The immunosuppressive medications that have contributed greatly to the success of liver transplantation are also associated with posttransplant renal dysfunction. We reviewed measured glomerular filtration rate (GFR) data from patients who underwent transplantation more than 10 years ago to assess whether results from specific time points can predict renal failure.

    Title Acute Kidney Injury Following Liver Transplantation: Definition and Outcome.
    Date July 2009
    Journal Liver Transplantation : Official Publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society
    Excerpt

    The incidence of acute kidney injury (AKI) has been reported to vary between 17% and 95% post-orthotopic liver transplantation. This variability may be related to the absence of a uniform definition of AKI in this setting. The purpose of this study was to identify the degree of AKI that is associated with long-term adverse outcome. Furthermore, to determine the best definition (for use in future studies) of AKI not requiring dialysis in post-liver transplant patients, we retrospectively reviewed the effect of 3 definitions of AKI post-orthotopic liver transplantation on renal and patient outcome between 1997 and 2005. We compared patients with AKI to a control group without AKI by each definition. AKI was defined in 3 groups as an acute rise in serum creatinine, from the pretransplant baseline, of >0.5 mg/dL, >1.0 mg/dL, or >50% above baseline to a value above 2 mg/dL. In all groups, the glomerular filtration rate was significantly lower at both 1 and 2 years post-transplant. Patient survival was worse in all groups. Graft survival was worse in all groups. The incidence of AKI was highest in the group with a rise in creatinine of >0.5 mg/dL (78%) and lowest in patients with a rise in creatinine of >50% above 2.0 mg/dL (14%). Even mild AKI, defined as a rise in serum creatinine of >0.5 mg/dL, was associated with reduced patient and graft survival. However, in comparison with the other definitions, the definition of AKI with the greatest impact on patient's outcome post-liver transplant was a rise in serum creatinine of >50% above baseline to >2 mg/dL.

    Title Simultaneous Liver-kidney Transplantation: Evaluation to Decision Making.
    Date August 2007
    Journal American Journal of Transplantation : Official Journal of the American Society of Transplantation and the American Society of Transplant Surgeons
    Excerpt

    Questions about appropriate allocation of simultaneous liver and kidney transplants (SLK) are being asked because kidney dysfunction in the context of liver failure enhances access to deceased donor organs. There is specific concern that some patients who undergo combined liver and kidney transplantation may have reversible renal failure. There is also concern that liver transplants are placed prematurely in those with end-stage renal disease. Thus to assure allocation of transplants only to those truly in need, the transplant community met in March 2006 to review post-MELD (model for end-stage liver disease) data on the impact of renal function on liver waitlist and transplant outcomes and the results of SLK.

    Title Graft Vs Host Disease Following Kidney Transplantation Using an '0 Hla Antigen Mismatched' Donor.
    Date October 2006
    Journal Nephrology, Dialysis, Transplantation : Official Publication of the European Dialysis and Transplant Association - European Renal Association
    Title Cadaveric Orthotopic Auxiliary Split Liver Transplantation and Kidney Transplantation: an Alternative for Type 1 Primary Hyperoxaluria.
    Date August 2005
    Journal Transplantation
    Excerpt

    Liver transplantation (LTX) corrects the enzymatic defect responsible for type 1 primary hyperoxaluria (PH1). It has been advocated in combination with kidney transplantation (KTX) in patients with renal failure from PH1 because KTX alone can result in early graft loss. A 58-year-old male patient with PH1 on hemodialysis underwent resection of the left lateral segment of the liver followed by orthotopic auxiliary left lateral segment liver transplantation and kidney transplantation from a deceased donor. The serum oxalate dropped from 34.8 micromol/L before transplant to 3.6-8.3 in the first months posttransplant to <1 micromol/L (normal range 0.4-3.0). One year after posttransplant, the patient has an iothalamate glomerular filtration rate of 58 ml/min. Orthotopic auxiliary LTX is an alternative to whole LTX in PH1. By using a split deceased donor liver, it does not deprive the donor pool and protects the recipient from liver failure in case of graft loss.

    Title Preoperative and Perioperative Predictors of the Need for Renal Replacement Therapy After Orthotopic Liver Transplantation.
    Date November 2004
    Journal Transplantation
    Excerpt

    BACKGROUND: Acute renal failure developing after orthotopic liver transplantation (OLTx) requiring renal replacement heralds a poor prognosis. Our center has previously reported a 1-year survival of only 41.8%. We undertook this study to determine whether we could identify preoperative and perioperative factors that would predict which patients are at risk. METHODS: OLTxs performed between January 1, 1996, and December 31, 2001, were included in our retrospective database review. Combined kidney-liver transplants or patients with preoperative renal replacement therapy (RRT) were excluded. A total of 724 OLTxs were studied, which were divided into group I: no RRT, n=637; group II: hemodialysis only post-OLTx, n=17; and group III: continuous RRT post-OLTx, n=70. Univariate and stepwise logistic multivariate analyses were performed. RESULTS: Preoperative serum creatinine greater than 1.9 mg/dL (odds ratio [OR] 3.57), preoperative blood urea nitrogen greater than 27 mg/dL (OR 2.68), intensive care unit stay more than 3 days (OR 10.23), and Model for End-Stage Liver Disease score greater than 21 (OR 2.5) were significant. A clinical prediction model was constructed: probability of requiring dialysis posttransplant=(-2.4586+1.2726 [creatinine >1.9] + 0.9858 [blood urea nitrogen >27] + 0.4574 [Model for End-Stage Liver Disease score >21] + 1.1625 [intensive care unit days >3]). A clinical prediction rule for patients with a score greater than 0.12 was applied to OLTx recipients who underwent transplantation in 2002. A total of 15 of 20 patients who received RRT and 111 of 121 who did not were correctly classified with the model. CONCLUSIONS: This model allowed us to identify patients at high risk for developing the need for RRT postoperatively. Strategies for these patients to prevent or ameliorate acute renal failure and reduce the need for RRT postoperatively are needed.

    Title Rhabdomyolysis After Concomitant Use of Cyclosporine, Simvastatin, Gemfibrozil, and Itraconazole.
    Date October 2002
    Journal The Annals of Pharmacotherapy
    Excerpt

    OBJECTIVE: To report a case of rhabdomyolysis in a patient receiving cyclosporine, simvastatin, gemfibrozil, and itraconazole. CASE REPORT: Rhabdomyolysis occurring in transplant patients receiving both cyclosporine and the hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor lovastatin has been well documented. The exact mechanism by which this interaction leads to rhabdomyolysis is unknown. Experience with newer agents of the statin drug class in transplant patients is limited. Since the interaction between cyclosporine and HMG-CoA reductase inhibitors involves the CYP3A4 enzyme system, the possibility of amplifying this interaction exists when other drugs affecting the same enzyme system are coprescribed. We describe a case in which a heart transplant recipient stable on a drug regimen that included cyclosporine, simvastatin, and gemfibrozil developed rhabdomyolysis after initiation of the antifungal agent itraconazole. DISCUSSION: Drug-drug interactions due to shared metabolism via the CYP3A4 pathway can result in significant adverse outcomes. This article discusses concurrent use of an HMG-CoA reductase inhibitor with other drugs that inhibit the CYP3A4 isoenzyme, leading to a case of possible fatal rhabdomyolysis. CONCLUSIONS: Clinicians must be aware of drugs metabolized via cytochrome P450 isoenzymes and identify those requiring risk-versus-benefit analysis before prescribing. Patients need to be educated as to signs and symptoms requiring immediate physician intervention.

    Title End-stage Renal Disease (esrd) After Orthotopic Liver Transplantation (oltx) Using Calcineurin-based Immunotherapy: Risk of Development and Treatment.
    Date January 2002
    Journal Transplantation
    Excerpt

    BACKGROUND: The calcineurin inhibitors cyclosporine and tacrolimus are both known to be nephrotoxic. Their use in orthotopic liver transplantation (OLTX) has dramatically improved success rates. Recently, however, we have had an increase of patients who are presenting after OLTX with end-stage renal disease (ESRD). This retrospective study examines the incidence and treatment of ESRD and chronic renal failure (CRF) in OLTX patients. METHODS: Patients receiving an OLTX only from June 1985 through December of 1994 who survived 6 months postoperatively were studied (n=834). Our prospectively collected database was the source of information. Patients were divided into three groups: Controls, no CRF or ESRD, n=748; CRF, sustained serum creatinine >2.5 mg/dl, n=41; and ESRD, n=45. Groups were compared for preoperative laboratory variables, diagnosis, postoperative variables, survival, type of ESRD therapy, and survival from onset of ESRD. RESULTS: At 13 years after OLTX, the incidence of severe renal dysfunction was 18.1% (CRF 8.6% and ESRD 9.5%). Compared with control patients, CRF and ESRD patients had higher preoperative serum creatinine levels, a greater percentage of patients with hepatorenal syndrome, higher percentage requirement for dialysis in the first 3 months postoperatively, and a higher 1-year serum creatinine. Multivariate stepwise logistic regression analysis using preoperative and postoperative variables identified that an increase of serum creatinine compared with average at 1 year, 3 months, and 4 weeks postoperatively were independent risk factors for the development of CRF or ESRD with odds ratios of 2.6, 2.2, and 1.6, respectively. Overall survival from the time of OLTX was not significantly different among groups, but by year 13, the survival of the patients who had ESRD was only 28.2% compared with 54.6% in the control group. Patients developing ESRD had a 6-year survival after onset of ESRD of 27% for the patients receiving hemodialysis versus 71.4% for the patients developing ESRD who subsequently received kidney transplants. CONCLUSIONS: Patients who are more than 10 years post-OLTX have CRF and ESRD at a high rate. The development of ESRD decreases survival, particularly in those patients treated with dialysis only. Patients who develop ESRD have a higher preoperative and 1-year serum creatinine and are more likely to have hepatorenal syndrome. However, an increase of serum creatinine at various times postoperatively is more predictive of the development of CRF or ESRD. New strategies for long-term immunosuppression may be needed to decrease this complication.

    Title Renal Replacement Therapy and Orthotopic Liver Transplantation: the Role of Continuous Veno-venous Hemodialysis.
    Date July 2001
    Journal Transplantation
    Excerpt

    BACKGROUND: The need for renal replacement therapy (RRT) either before or after orthotopic liver transplant (OLTX) has been reported to be a poor prognostic indicator for survival. Use of continuous veno-venous hemodialysis (CVVHD) for RRT has been reported in three series of OLTX patients with high 90-day mortality rates of 57-60%. We have examined our patient population to determine the effect of necessity and type of RRT on patient survival after OLTX. METHODS: We analyzed 1535 OLTX that were performed at our institution from 1985 through 1999, 1037 from 1985 to 1995 (period I) and 498 from 1996 to 1999 (period II). Combined liver-kidney transplants were excluded from analysis. Hospital dialysis unit records and a prospectively maintained database on all OLTX patients served as the source of data. Patients were classified into groups defined on whether or not they received RRT, when they received RRT, and the type of RRT. Groups were compared for preoperative intensive care unit status, time on the waiting list, laboratory variables, 90-day postoperative mortality, 1-year patient survival, and absolute survival. RESULTS: Use of RRT increased from 8.29% in period I to 12.45% in period II, along with increased median waiting times. In period I, patients receiving preoperative RRT had a 90-day mortality (0%) and a 1-year survival (89.5%) almost identical to those patients who never required RRT (1.7% and 90.6%). Patients who developed acute renal failure postoperatively requiring RRT, however, had a 90-day mortality of 28.6% and a 1-year survival of 55%. In period II, patients requiring RRT had a 90-day mortality of 39.7% and a 1-year actuarial survival of 54.5% compared with 6.9% and 88.6% in patients never requiring RRT. Patients treated with CVVHD had a 90-day mortality of 42% compared with 25% in patients treated with hemodialysis alone. However, patients receiving CVVHD both pre- and postoperatively had a 90-day mortality of 27.7% vs. 50% in those patients who only received CVVHD postoperatively. Patients who developed acute renal failure postoperatively, which required RRT, regardless of therapy, had a 1-year survival of only 41.0% compared with a 1-year survival of 73.6% in those patients started on RRT preoperatively, P=0.03. CONCLUSIONS: The need for RRT has increased along with waiting time in OLTX patients. Patients developing the need for RRT postoperatively have an increased 90-day mortality and lower 1-year survival with the highest being present in patients receiving CVVHD, which was started postoperatively. These findings may reflect a trend toward a sicker population awaiting OLTX and emphasize the negative impact of renal failure on survival after OLTX.

    Title Ammonia Transport by the Urinary Bladder of Bufo Marinus.
    Date December 1996
    Journal Comparative Biochemistry and Physiology. Part A, Physiology
    Excerpt

    All experiments were performed in vitro on toad bladders. Bladder sacs from acidotic toads produced a concentration gradient across the bladder with both [NH3] and [NH4] higher in the mucosal media. By varying the pH of the serosal media, paired sacs from normal toads were incubated with similar [NH3] in the serosal media but a 75 fold difference in [NH4] of the serosal media of the pairs. The hemibladders with the higher [NH4] had a 2.4 fold greater excretory flux than the paired sac. Both serosal to mucosal and mucosal to serosal fluxes were determined in normal bladders between chambers at various ammonium concentration gradients. The plot of mucosal to serosal flux against concentration produced a curve compatible with both carrier mediated and diffusion transport; the plot of serosal to mucosal flux produced a straight line with flux increasing when the ammonium concentration was increased. The serosal to mucosal transepithelial flux was augmented by making the serosal side of the bladder 50 mV positive. Although NH3 diffusion may occur, it cannot be the primary method of ammonia transport in the toad bladder.

    Title Pancreas Transplantation for Diabetes Mellitus.
    Date May 1996
    Journal American Journal of Kidney Diseases : the Official Journal of the National Kidney Foundation
    Excerpt

    Pancreas transplantation has become a viable option for the patient wi th insulin-dependent diabetes mellitus with progressive renal failure. The most common type of pancreas transplantation is a simultaneous pancreas and kidney transplantation performed from a single cadaver donor (SPK). The next most common is pancreas transplantation after successful kidney transplantation (PAK). A few centers are performing pancreas transplantation alone (PTA) in diabetic recipients without renal disease but who have significant complications from their diabetes. Pancreas transplantation is associated with a higher morbidity than kidney transplantation alone. Most pancreas transplantation centers report a significant increase in acute rejection, which can lead to increased hospitalization and risk of opportunistic infection. In addition, the early era of pancreas transplantation was associated with significant surgical complications. However, with bladder drainage of the pancreas exocrine secretions, the surgical complication rate has decreased significantly. Despite medical and surgical complications, the overall results for pancreas transplantation are excellent, with 1 -year graft survival of 75% for SPK transplantations and 48% for PAK and PTA transplant recipients. The effects of a pancreas transplantation on the secondary complications of diabetes have been studied extensively. Most studies have shown a modest improvement in secondary complications with the exception of diabetic retinopathy. The major benefit of pancreas transplantation appears to be enhanced quality of life for patients successfully transplanted. For these reasons, the Kidney-Pancreas Committee of the American Society of Transplant Physicians believes the current results of pancreas-kidney transplantation justify its use as a valid option for insulin-dependent diabetic transplant recipients.

    Title Pancreas Transplantation.
    Date July 1992
    Journal Seminars in Nephrology
    Title The Role of Interleukin-6 in Mitogenic T-cell Activation: Detection of Interleukin-2 Heteronuclear Rna by Polymerase Chain Reaction.
    Date May 1991
    Journal Cellular Immunology
    Excerpt

    It has been documented that interleukin-6 (IL-6) supports the proliferation of purified, anti-CD3-stimulated murine T cells. We found that stimulation of human peripheral blood mononuclear cells (PBMCs) with anti-CD3 induced a significant accumulation of IL-6 mRNA, indicating that antigen-mediated T-cell activation may involve IL-6 release from accessory cells. Phytohemagglutinin (PHA) had little effect upon IL-6 gene expression. In keeping with these findings, anti-IL-6 reduced but did not abolish anti-CD3-mediated proliferation of PBMCs, but had no significant effect upon PHA-stimulated proliferation. The addition of recombinant (r) IL-6 enhanced the proliferation of anti-CD3-stimulated PBMCs and increased the accumulation of IL-2 mRNA in PHA-stimulated PBMCs during the first 5 hr of culture. Nuclear run-off experiments did not reveal significant changes in IL-2 transcription in PHA plus rIL-6-treated PBMCs attempting to assume that IL-6 mediates stabilization of IL-2 mRNA. However, monitoring of partially spliced IL-2 mRNA by polymerase chain reaction revealed a clear increase in IL-2 heteronuclear RNA. Thus IL-6 increases the rate of IL-2 transcription which was not detectable by conventional in vitro transcription assays. We conclude that anti-CD3 triggers T-cell proliferation through a process that is partially but not entirely dependent upon release of IL-6. IL-6, in turn, supports IL-2 transcription. Insofar as anti-CD3 mimics antigen-triggered activation of the T-cell receptor complex, IL-6 appears to support the early immune response by augmenting antigen-triggered IL-2 gene expression.

    Title Requirements for Primary T Cell Activation.
    Date August 1990
    Journal Transplantation Proceedings
    Title Possible Association of the Immunosuppressive and B Cell Lymphoma-promoting Properties of Cyclosporine.
    Date February 1990
    Journal Transplantation
    Excerpt

    Central to the immunosuppressive properties of cyclosporine is a drug imposed blockade of the interleukin-2 gene activation. As IL-6 stimulates antigen-activated T cells to release IL-2, we examined the influence of CsA on IL-6 gene expression and IL-6-supported T cell proliferation. Northern blot analysis revealed that CsA failed to abolish IL-6 gene expression in mitogen-activated peripheral blood mononuclear cells. In fact, increased IL-6 gene transcription and increased release of IL-6 bioactivity were detected using mitogen-activated PBMCs cultured with CsA doses (200-800 ng/ml) only slightly in excess of the minimal antiproliferative dose. CsA completely abrogated the IL-6-stimulated proliferative responses of macrophage-depleted T cells stimulated with polyvalent anti-CD3 monoclonal antibodies. It is interesting that CsA-treated patients evidence an increased incidence of polyclonal lymphoproliferative disorders and B cell lymphomas. As IL-6 fosters B cell activation and growth of EBV-transformed B cells, excessive CsA doses may support development of EBV-transformed B cell lymphomas via superinduction of the IL-6 gene.

    Title Antibody Valence and Induced Signal Transduction: the Role of Antibody Valence in Anti-cd3-induced Signal Transduction in Isolated Normal T Cells.
    Date March 1989
    Journal Clinical Immunology and Immunopathology
    Excerpt

    This report provides direct evidence that protein kinase C (PKC) is activated in isolated, rigorously accessory cell (AC)-depleted T cells when the T cell antigen recognition complex is stimulated by divalent anti-CD3 monoclonal antibody. Anti-CD3 monoclonal antibody-stimulated PKC activation alone does not, however, directly stimulate T cell proliferation in the absence of AC. A rise in cytosolic calcium is the second signal believed to be of paramount importance in T cell activation. While mitogenic concentrations of some divalent anti-CD3 antibodies do not cause a rise in cytosolic calcium, polyvalent anti-CD3 does evoke increased intracellular Ca2+ in rigorously AC-depleted resting human T cells.

    Title Endotoxin-associated Protein: Interleukin-1-like Activity on Serum Amyloid A Synthesis and T-lymphocyte Activation.
    Date June 1988
    Journal Infection and Immunity
    Excerpt

    Bacterial endotoxins or lipopolysaccharides (LPS) elicit a variety of biologic activities in intact animals and various in vitro systems. LPS from most gram-negative bacteria have appeared to have similar biologic activities regardless of the species of origin or method of preparation of the LPS. More recent studies have suggested differences in the effects of protein-rich as opposed to protein-free LPS in inducing mitogenesis of lymphocytes from endotoxin-resistant C3H/HeJ mice. These studies examine other activities of endotoxin-associated protein (EAP), purified to less than 0.007% contamination with LPS, and demonstrate that this material has activity mimicking some of the effects of interleukin-1 (IL-1). EAP proved to be as potent as LPS in eliciting rises in concentrations of serum amyloid A (SAA) and was active in both endotoxin-sensitive (CF1) and endotoxin-resistant (C3H/HeJ) mice. In contrast to LPS, which mediates its SAA-inducing activity by release of an inducer (IL-1) from LPS-stimulated macrophages, EAP appeared to act directly to induce SAA production, in that incubation with macrophages failed to increase its activity. EAP also exhibited IL-1-like activity in the lymphocyte-activating factor assay when both CF1 and C3H/HeJ thymocytes and macrophages were tested. The lymphocyte-activating factor activity of EAP was not blocked by addition of polymyxin B. In addition, EAP exerted stimulatory activity on resting human T lymphocytes, costimulated with Sepharose-bound anti-CD3 monoclonal antibody 64.1, comparable to that observed with purified human monocyte IL-1. These studies indicate that proteins from procaryotic cells may act as cytokines for some eucaryotic cells.

    Title Ammoniuretic Activity of Dog Plasma when Tested on Urinary Bladder of Bufo Marinus.
    Date October 1980
    Journal Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (new York, N.y.)
    Title Stimulation of Ammonium Ion Excretion in the Toad Urinary Bladder by an Extract of Human Urine.
    Date August 1979
    Journal Biochimica Et Biophysica Acta
    Excerpt

    It is well known that ammonium ion excretion is increased during metabolic acidosis in mammals. The purpose of this study was to determine whether we could isolate from human urine during metabolic acidosis a factor that would stimulate NH+4 and/or H+ excretion in toad urinary bladder. Extracts of urine from six human subjects collected during NH4Cl-induced acidosis were prepared. These extracts were tested for their effect on NH+4 excretion in hemibladders mounted between plastic chambers. The extracts significantly increased NH+4 excretion in the toad urinary bladder. We found no effect on H+ excretion by these extracts. This ammoniuretic activity was not present in the urine when the same individuals were in metabolic alkalosis. We conclude that during metabolic acidosis a humoral factor is present which stimulates the excretion of NH+4. The factor could act as a permease in the bladder cell or as a stimulator of an NH+4 transport system.

    Title The Effect of Angiotensin Ii on Electrolyte Excretion by the Renal Tubules.
    Date November 1977
    Journal Texas Reports on Biology and Medicine
    Excerpt

    In vivo studies were done on mongrel dogs to determine the effect of angiotensin II on renal electrolyte excretion. Angiotensin II was infused directly into the left renal artery at a rate of 1 ng/kg/min. Angiotensin produced consistent reductions in the excretion of Na+, K+, and Cl- in the left kidney. These reductions could not be attributed to decreases in GFR or RPF. Electrolyte excretion by the right kidney was constant. These data are consistent with the hypothesis that angiotensin II may function as an intrarenal, antinatriuretic hormone.

    Title Indications for Combined Liver and Kidney Transplantation: Propositions After a 23-yr Experience.
    Date
    Journal Clinical Transplantation
    Excerpt

    The frequency of combined liver and kidney transplants (CLKT) persists despite the pronounced scarcity of organs. In this review, we sought to ascertain any factors that would reduce the use of these limited commodities. Seventy-five adult CLKT were performed over a 23-yr period at our center, 29 (39%) of which occurred during the Model for End-stage Liver Disease (MELD) era. Overall, patient survival rates were 82%, 73%, and 62% at one, three, and five yr, respectively. There was no difference in patient survival based either on pre-transplant hemodialysis status or by glomerular filtration rate (GFR) at the time of transplant. Patients undergoing a second CLKT or a liver retransplantation at the time of CLKT had a survival rate of 30% at three months. In the MELD era, patient survival was unchanged (p = NS) despite an older recipient population (p = 0.0029) and a greater number of hepatitis C patients (p = 0.0428). In summary, patients requiring liver retransplantation with concomitant renal failure should be denied CLKT. Renal allografts may also be spared by implementing strict criteria for renal organ allocation (GFR < 30 mL/min at the time of evaluation) and considering the elimination of preemptive kidney transplantation in CLKT.

    Title Whole-organ Pancreas Transplantation at Baylor Regional Transplant Institute: a Chance to Cure Diabetes.
    Date
    Journal Proceedings (baylor University. Medical Center)
    Excerpt

    The success of pancreas transplantation has improved over the past several decades with advancements in surgical technique, immunosuppressive medicines, and immunologic testing. We retrospectively reviewed our experience with pancreas transplantation from 1995 to 2008. At the Baylor Regional Transplant Program, 151 pancreas transplants were performed in 147 patients: 135 were simultaneous pancreas-kidney transplants, 10 were pancreas transplants after kidney transplants, and 6 were pancreas transplants alone. Follow-up information was available for 138 patients. The 1-year acute cellular rejection rate was 31.6%; the 30-day surgical reexploration rate was 10%; and the technical failure rate was 5.3%. Five-year pancreas graft survival rates were 67% for simultaneous pancreas and kidney transplants and 50% for pancreas transplants after kidney transplants. These outcomes exceed expected results as calculated by the Scientific Registry of Transplant Recipients. In addition, the median time to transplant was 3.8 months, compared with a US median of 14.1 months. Pancreas transplantation is currently the closest thing to a cure for diabetes and should be given as an option for diabetic patients with or without end-stage renal disease.


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