Jack F M Wetzels

Radboud University Medical Centre (Radboudumc), Nymegen, Gelderland, Netherlands

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Publications (363)1952.05 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In rodents, parietal epithelial cells (PECs) migrating onto the glomerular tuft participate in the formation of focal segmental glomerulosclerosis (FSGS) lesions. We investigated whether immunohistologic detection of PEC markers in the initial biopsies of human patients with first manifestation of idiopathic nephrotic syndrome with no immune complexes can improve the sensitivity to detect sclerotic lesions compared with standard methods. Ninety-five renal biopsies were stained for claudin-1 (PEC marker), CD44 (activated PECs), and LKIV69 (PEC matrix); 38 had been diagnosed as early primary FSGS and 57 as minimal change disease. PEC markers were detected on the tuft in 87% of the biopsies of patients diagnosed as primary FSGS. PEC markers were detected in FSGS lesions from the earliest stages of disease. In minimal change disease, no PEC activation was observed by immunohistology. However, in 25% of biopsies originally diagnosed as minimal change disease the presence of small lesions indicative of a sclerosing process were detected, which were undetectable on standard periodic acid-Schiff staining, even though only a single histologic section for each PEC marker was evaluated. Staining for LKIV69 detected lesions with the highest sensitivity. Two novel PEC markers A-kinase anchor protein 12 and annexin A3 exhibited similar sensitivity. In summary, detection of PECs on the glomerular tuft by immunostaining improves the differentiation between minimal change disease and primary FSGS and may serve to guide clinical decision making.
    The American Journal of Pathology. 10/2014;
  • Jeroen Deegens, Jack Wetzels
    Nature Reviews Nephrology 08/2014; · 7.94 Impact Factor
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    ABSTRACT: The optimal timing and duration of immunosuppressive therapy for idiopathic membranous nephropathy (iMN) have been debated. This study aimed to evaluate whether measuring the antibody against the phospholipase A2 receptor (PLA2R-ab) at start and end of therapy predicts long-term outcome and therefore may inform this debate.DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This observational study included all consecutive high-risk patients with progressive iMN observed from 1997 to 2005 and treated with oral cyclophosphamide (CP) or mycophenolate mofetil (MMF) in combination with corticosteroids for 12 months. Patients were prospectively followed, and outcome was ascertained up to 5 years after completion of immunosuppressive therapy. Serum samples were collected before and after completion of therapy. PLA2R antibodies were determined retrospectively in stored samples using ELISA.RESULTS: In total, 48 patients (37 men) were included. The median age was 55 years (range, 34-75), and the median serum creatinine level was 1.60 mg/dl (range, 0.98-3.37 mg/dl). Twenty-two patients received MMF and 26 received CP. At baseline, PLA2R-abs were present in 34 patients (71%). Baseline characteristics and outcome did not significantly differ between patients negative or positive for PLA2R-ab. In PLA2R-ab-positive patients, treatment resulted in a rapid decrease of antibodies: median anti-PLA2R-ab, 428 U/ml (range, 41-16,260 U/ml) at baseline and 24 U/ml (range, 0-505 U/ml) after 2 months. The PLA2R-ab levels at baseline did not predict initial response, but antibody status at end of therapy predicted long-term outcome: After 5 years, 14 of 24 (58%) antibody-negative patients were in persistent remission compared with 0 of 9 (0%) antibody-positive patients (P=0.003).CONCLUSIONS: These data suggest that in PLA2R-ab-positive patients, measuring PLA2R-abs at the end of therapy predicts the subsequent course.
    Clinical journal of the American Society of Nephrology : CJASN. 07/2014;
  • Jeroen K Deegens, Jack F Wetzels
    Nature Reviews Nephrology 06/2014; · 7.94 Impact Factor
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    ABSTRACT: Cyclophosphamide treatment improves renal survival in patients with idiopathic membranous nephropathy. However, use of cyclophosphamide is associated with cancer. The incidence of malignancies in patients with idiopathic membranous nephropathy was evaluated, and the cancer risk associated with cyclophosphamide use was estimated.DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Patients who attended the clinic were included prospectively from 1995 on. A crude incidence ratio for the occurrence of malignancy was calculated. Incidence ratios were subsequently standardized to potential confounders. Latency between cyclophosphamide therapy and the occurrence of cancer was estimated by stratifying for time since the start of treatment. Finally, Poisson regression was used to obtain a multiple adjusted incidence ratio and investigate the dose-response relationship between cyclophosphamide and cancer.RESULTS: Data were available for 272 patients; the mean age was 51 years, and 70% of the patients were men. Median follow-up was 6.0 years (interquartile range=3.6-9.5), and 127 patients were treated with cyclophosphamide. Cancer incidence was 21.2 per 1000 person-years in treated patients compared with 4.6 per 1000 person-years in patients who did not receive cyclophosphamide, resulting in crude and adjusted incidence ratios of 4.6 (95% confidence interval, 1.5 to 18.8) and 3.2 (95% confidence interval, 1.0 to 9.5), respectively.CONCLUSION: Cyclophosphamide therapy in idiopathic membranous nephropathy gives a threefold increase in cancer risk. For the average patient, this finding translates into an increase in annual risk from approximately 0.3% to 1.0%. The increased risk of malignancy must be balanced against the improved renal survival.
    Clinical journal of the American Society of Nephrology : CJASN. 05/2014;
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    05/2014; 29 Suppl 3:iii90-iii101.
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    ABSTRACT: Achtergrond In de eerste lijn komt chronische nierschade onder patiënten met diabetes of hypertensie veel voor. Deze cardiovasculaire risicofactor wordt echter vaak onvoldoende aangepakt. Een samenwerkingsmodel waarin huisartsen en praktijkondersteuners via internet een nefroloog kunnen consulteren, zou dat kunnen verbeteren. Methode Wij voerden een cluster-RCT uit in negen huisartsenpraktijken, onder patiënten met diabetes of hypertensie en chronische nierschade (geschatte glomerulaire filtratiesnelheid < 60ml/min/1,73 m2), Vijf praktijken pasten een jaar lang het samenwerkingsmodel toe en vier praktijken leverden reguliere zorg. Onze belangrijkste uitkomstmaten waren de gemiddelde bloeddrukverlaging en het percentage deelnemers dat de streefbloeddruk (≤ 130/80 mmHg) bereikte. Resultaten Wij analyseerden de gegevens van 90 patiënten in de interventiegroep en 74 in de controlegroep. De kans dat een patiënt een systolische bloeddruk van 130 mmHg bereikte, was in de interventiegroep 2,9 keer zo groot als in de controlegroep (95%-BI 1,4 tot 5,8), de kans op een diastolische bloeddruk van 90 mmHg was 2,5 keer zo groot (95%-BI 1,3 tot 4,7). In de interventiegroep nam de systolische bloeddruk af met 8,1 mmHg (95%-BI 4,8 tot 11,3), de diastolische met 1,1 mmHg (95%-BI –1,0 tot 3,2), tegenover –0,2 mmHg (95%-BI –3,8 tot 3,3) respectievelijk –0,5 mmHg (95%-BI –2,9 tot 1,8) in de controlegroep. In de interventiegroep lag bovendien het gebruik van lipidenverlagende middelen, RAS-remmers en vitamine D hoger en waren de concentraties parathormoon lager. Conclusie Een samenwerkingsmodel waarin huisarts, praktijkondersteuner en nefroloog samenwerken in de begeleiding van patiënten met diabetes of hypertensie en chronische nierschade, leidt tot een significant lagere systolische bloeddruk dan reguliere zorg.
    Huisarts en wetenschap 05/2014; 57(5):232-235.
  • 05/2014; 29 Suppl 3:iii79-iii89.
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    ABSTRACT: Slit diaphragm and podocyte damage is crucial in proteinuria pathogenesis in diabetic nephropathy (DNP). Gain-of-function mutations in TRPC6, a slit diaphragm-associated ion channel, cause glomerulosclerosis; TRPC6 expression is increased in acquired glomerular disease. Hyperglycemia and high intrarenal angiotensin II (AngII) levels could contribute to podocyte injury in DNP. We determined whether glucose regulates TRPC6 expression and TRPC6-mediated Ca(2+) influx into the podocyte and whether these effects are AngII dependent. High glucose levels increased TRPC6 mRNA and protein expression in cultured podocytes; however, TRPC1 and TRPC5 mRNA expression was unaltered. AngII and induced podocyte injury also specifically increased TRPC6 expression. Angiotensin receptor blockade and inhibition of local AngII production through angiotensin-converting enzyme inhibition prevented glucose-mediated increased TRPC6 expression. In addition, high glucose concentration pretreatment enhanced Ca(2+) influx in podocytes, which was prevented by concomitant angiotensin receptor blockade application and TRPC6 knockdown. Studies with a TRPC6 luciferase promoter construct demonstrated a glucose concentration-dependent effect on TRPC6 promoter activity. In vivo, podocyte TRPC6 protein expression was increased in proteinuric streptozotocin-induced diabetic rats. These data suggest that glucose can activate a local renin-angiotensin system in the podocyte, leading to increased TRPC6 expression, which enhances TRPC6-mediated Ca(2+) influx. Regulation of TRPC6 expression could be an important factor in podocyte injury due to chronic hyperglycemia and the antiproteinuric effect of angiotensin receptor blockade or angiotensin-converting enzyme inhibition in DNP.
    American Journal Of Pathology 04/2014; · 4.60 Impact Factor
  • Julia M Hofstra, Jack F M Wetzels
    Journal of the American Society of Nephrology 03/2014; · 8.99 Impact Factor
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    ABSTRACT: Membranous nephropathy, focal segmental glomerulosclerosis (FSGS), and minimal change disease (MCD) are the most common causes of idiopathic nephrotic syndrome. For many years prednisone, alkylating agents, and calcineurin inhibitors have been the standard of therapy for these patients. More effective or better tolerated treatment modalities are needed. B cell targeted therapy was recently introduced in clinical practice. In this review, we briefly summarize the current standard therapy and discuss the efficacy of B cell targeted therapy in primary glomerular diseases. Observational, short-term studies suggest that rituximab is effective and comparable to standard therapy in maintaining remissions in patients with frequently relapsing or steroid-dependent MCD or FSGS. In contrast, response is limited in patients with steroid-resistant nephrotic syndrome. Rituximab also induces remissions in patients with membranous nephropathy. Controlled clinical trials on kidney endpoints are urgently needed to position B cell targeted therapy in clinical practice.
    Advances in chronic kidney disease 03/2014; 21(2):166-181. · 2.42 Impact Factor
  • Rutger J H Maas, Jack F M Wetzels, Jeroen K J Deegens
    Kidney International 03/2014; 85(3):711. · 8.52 Impact Factor
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    ABSTRACT: Promising renal replacement therapies include the development of a bio-artificial kidney using functional human kidney cell models. In this study, human conditionally immortalized proximal tubular epithelial cell (ciPTEC) lines originating from kidney tissue (ciPTEC-T1 and ciPTEC-T2) were compared to ciPTEC previously isolated from urine (ciPTEC-U). Subclones of all ciPTEC isolates formed tight cell layers on Transwell inserts as determined by transepithelial resistance, inulin diffusion, E-cadherin expression and immunocytochemisty. Extracellular matrix genes collagen I and -IV α1 were highly present in both kidney tissue derived matured cell lines (p<0.001) compared to matured ciPTEC-U, whereas matured ciPTEC-U showed a more pronounced fibronectin I and laminin 5 gene expression (p<0.01 and p<0.05, respectively). Expression of the influx carrier Organic Cation Transporter 2 (OCT-2), and the efflux pumps P-glycoprotein (P-gp), Multidrug Resistance Protein 4 (MRP4) and Breast Cancer Resistance Protein (BCRP) were confirmed in the three cell lines using real-time PCR and Western blotting. The activities of OCT-2 and P-gp were sensitive to specific inhibition in all models (p<0.001). The highest activity of MRP4 and BCRP was demonstrated in ciPTEC-U (p<0.05). Finally, active albumin reabsorption was highest in ciPTEC-T2 (p<0.001), while Na(+)-dependent phosphate reabsorption was most abundant in ciPTEC-U (p<0.01). In conclusion, ciPTEC established from human urine or kidney tissue display comparable functional PTEC specific transporters and physiological characteristics, providing ideal human tools for bioartificial kidney development.
    Experimental Cell Research 02/2014; · 3.56 Impact Factor
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    ABSTRACT: The soluble urokinase receptor (suPAR) promotes proteinuria and induces focal segmental glomerulosclerosis (FSGS)-like lesions in mice. A serum suPAR concentration cutoff of 3000 pg/ml has been proposed as a clinical biomarker for patients with FSGS. Interestingly, several studies in patients with glomerulopathy found an inverse correlation between the estimated glomerular filtration rate (eGFR) and suPAR. As patients with FSGS present at different eGFRs, we studied the relationship between eGFR and suPAR in a cohort of 476 non-FSGS patients and 54 patients with biopsy-proven idiopathic FSGS. In the non-FSGS patients, eGFR was the strongest significant determinant of suPAR. The proposed cutoff for suPAR in FSGS patients was exceeded in 17%, 39%, and 88% in patients with eGFRs of more than 60, 45-60, and 30-45 ml/min per 1.73 m(2), respectively. In patients with eGFR of <30 ml/min per 1.73 m(2), suPAR exceeded the cutoff in 95% of patients. Levels of suPAR in patients with idiopathic FSGS overlapped with non-FSGS controls and for any given eGFR did not discriminate FSGS cases from non-FSGS controls. In the overall cohort, there was a negative association between idiopathic FSGS and suPAR, and idiopathic FSGS was not an independent predictor of FSGS concentration over 3000 pg/ml. Thus, this study does not support an absolute, eGFR-independent, suPAR concentration cutoff as a biomarker for underlying FSGS pathology and questions the validity of relative, eGFR-dependent suPAR cutoff values.Kidney International advance online publication, 8 January 2014; doi:10.1038/ki.2013.505.
    Kidney International 01/2014; · 8.52 Impact Factor
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    ABSTRACT: Activating mutations in the Transient Receptor Potential channel C6 (TRPC6) cause autosomal dominant focal segmental glomerular sclerosis (FSGS). TRPC6 expression is upregulated in renal biopsies of patients with idiopathic membranous glomerulopathy (iMN) and animal models thereof. In iMN, disease progression is characterized by glomerulosclerosis. In addition, a context-dependent TRPC6 overexpression was recently suggested in complement-mediated podocyte injury in e.g. iMN. Hence, we hypothesized that genetic variants in TRPC6 might affect susceptibility to development or progression of iMN.
    PLoS ONE 01/2014; 9(7):e102065. · 3.53 Impact Factor
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    ABSTRACT: Lithium is the most common cause of nephrogenic diabetes insipidus (Li-NDI). Hydrochlorothiazide (HCTZ) combined with amiloride is the mainstay treatment in Li-NDI. The paradox antidiuretic action of HCTZ in Li-NDI is generally attributed to increased sodium and water uptake in proximal tubules as a compensation for increased volume loss due to HCTZ inhibition of the NaCl-co-transporter (NCC), but alternative actions for HCTZ have been suggested. Here, we investigated whether HCTZ exerted an NCC-independent effect in Li-NDI. In polarized mouse cortical collecting duct (mpkCCD) cells, HCTZ treatment attenuated the Li-induced downregulation of the Aquaporin-2 (AQP2) water channel abundance. In these cells, amiloride reduces cellular Li influx through the epithelial sodium channel ENaC. HCTZ also reduced Li influx, but to a lower extent. HCTZ increased AQP2 abundance on top of that of amiloride and did not affect the ENaC-mediated transcellular voltage. MpkCCD cells did not express NCC mRNA or protein. These data indicated that in mpkCCD cells, HCTZ attenuated lithium-induced downregulation of AQP2 independent from NCC and ENaC. Treatment of Li-NDI NCC knockout mice with HCTZ revealed a significantly reduced urine volume, unchanged urine osmolality and increased cortical AQP2 abundance as compared to Li-treated NCC knockout mice. HCTZ treatment further resulted in reduced blood Li levels, creatinine clearance, and alkalinized urinary pH. Our in vitro and in vivo data indicate that part of the antidiuretic effect of HCTZ in Li-NDI is NCC-independent and may involve a tubuloglomerular feedback response mediated reduction in glomerular filtration rate due to proximal tubular carbonic anhydrase inhibition.
    AJP Renal Physiology 12/2013; · 4.42 Impact Factor
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    ABSTRACT: A single time-point fibroblast growth factor-23 (FGF23) level is a strong, well-established risk factor for clinical events in chronic kidney disease (CKD). This study investigated whether repeated measurements of FGF23 after 2 years, allowing the calculation of time-averaged FGF23 and the rate of change in FGF23, provided a better prediction of clinical events in CKD than a single time-point value. A post-hoc analysis was performed in a subset of 439 adult patients with a median estimated glomerular filtration rate of 36 (interquartile range 28-48) mL/min per 1.73 m(2) of the prospective multicentre MASTERPLAN study, in which paired samples to measure FGF23 were available. The primary outcome was defined as a composite of myocardial infarction, stroke and cardiovascular mortality and secondary end points, which were overall mortality, congestive heart failure (CHF) and start of renal replacement therapy. Only events occurring after Month 24 were included in the analysis. Analysis of different FGF23 measures showed that a single time-point value and time-averaged FGF23 were positively associated with the primary end point, and also with overall mortality, start of renal replacement therapy and CHF. The adjusted hazard ratios of a single value of FGF23 and of time-averaged FGF23 for the composite end points were 1.71 (CI 1.20-2.43) and 1.91 (CI 1.29-2.82), respectively. Change in FGF23 was not associated with any outcome except for the initiation of renal replacement therapy. Our study confirms that FGF23 is an important cardiovascular risk factor. Two measurements of FGF23 have no added value over a single value to predict the cardiovascular outcome. This study demonstrates that, under routine clinical practice, the variability of FGF23 in 2 years' time is small. Concomitantly, this study showed no benefit of consecutive FGF23 testing for estimating the risk of a clinical event in an individual patient.
    Nephrology Dialysis Transplantation 11/2013; · 3.37 Impact Factor
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    ABSTRACT: Treatment goals for patients with CKD are often unrealized for many reasons, but support by nurse practitioners may improve risk factor levels in these patients. Here, we analyzed renal endpoints of the Multifactorial Approach and Superior Treatment Efficacy in Renal Patients with the Aid of Nurse Practitioners (MASTERPLAN) study after extended follow-up to determine whether strict implementation of current CKD guidelines through the aid of nurse practitioners improves renal outcome. In total, 788 patients with moderate to severe CKD were randomized to receive nurse practitioner support added to physician care (intervention group) or physician care alone (control group). Median follow-up was 5.7 years. Renal outcome was a secondary endpoint of the MASTERPLAN study. We used a composite renal endpoint of death, ESRD, and 50% increase in serum creatinine. Event rates were compared with adjustment for baseline serum creatinine concentration and changes in estimated GFR were determined. During the randomized phase, there were small but significant differences between the groups in BP, proteinuria, LDL cholesterol, and use of aspirin, statins, active vitamin D, and antihypertensive medications, in favor of the intervention group. The intervention reduced the incidence of the composite renal endpoint by 20% (hazard ratio, 0.80; 95% confidence interval, 0.66 to 0.98; P=0.03). In the intervention group, the decrease in estimated GFR was 0.45 ml/min per 1.73 m(2) per year less than in the control group (P=0.01). In conclusion, additional support by nurse practitioners attenuated the decline of kidney function and improved renal outcome in patients with CKD.
    Journal of the American Society of Nephrology 10/2013; · 8.99 Impact Factor
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    ABSTRACT: Binding of vasopressin to its type-2 receptor in renal collecting ducts induces cAMP signaling, transcription and translocation of aquaporin-2 (AQP2) water channels to the plasma membrane and water reabsorption from the pro-urine. Demeclocycline is currently used to treat hyponatremia in patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Demeclocycline's mechanism of action, which is poorly understood, is studied here. In mouse cortical collecting duct (mpkCCD) cells, which exhibit dDAVP-dependent expression of endogenous AQP2, demeclocycline decreased AQP2 abundance and gene transcription, but not its protein stability. Demeclocycline did not affect V2R localization, but decreased dDAVP-induced cAMP generation and adenylate cyclase 3 and 5/6 abundances. Addition of exogenous cAMP partially corrected the demeclocycline effect. As in patients, demeclocycline increased urine volume, decreased urine osmolality and reverted hyponatremia in an SIADH rat model. AQP2 and adenylate cyclase 5/6 abundances were reduced in the inner medulla, but increased in the cortex and outer medulla, in the absence of any sign of toxicity. In conclusion, our in vitro and in vivo data indicate that demeclocycline mainly attenuates hyponatremia in SIADH by reducing adenylate cyclase 5/6 expression, and consequently cAMP generation, AQP2 gene transcription and AQP2 abundance in the renal inner medulla, coinciding with a reduced vasopressin-escape response in the other collecting duct segments.
    AJP Renal Physiology 10/2013; · 4.42 Impact Factor
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    ABSTRACT: Despite advances in preventive therapy, prognosis in chronic kidney disease (CKD) is still grim. Clinical cohorts of CKD patients provide a strategic resource to identify factors that drive progression in the context of clinical care and to provide a basis for improvement of outcome. The combination with biobanking, moreover, provides a resource for fundamental and translational studies. In 2007, the Dutch government initiated and funded the String of Pearls Initiative (PSI), a strategic effort to establish infrastructure for disease-based
    Nephrology Dialysis Transplantation 10/2013; · 3.37 Impact Factor

Publication Stats

5k Citations
1,952.05 Total Impact Points


  • 1985–2014
    • Radboud University Medical Centre (Radboudumc)
      • Department of Human Genetics
      Nymegen, Gelderland, Netherlands
  • 2012–2013
    • VU University Medical Center
      • Department of Nephrology
      Amsterdamo, North Holland, Netherlands
    • Oxford University Hospitals NHS Trust
      • Department of Radiology
      Oxford, ENG, United Kingdom
    • RWTH Aachen University
      • Nephrology and Clinical Immunology (Internal Medicine II)
      Aachen, North Rhine-Westphalia, Germany
  • 1987–2012
    • Radboud University Nijmegen
      • • Department of Physiology
      • • Department of Nephrology
      • • Department of General Internal Medicine
      Nijmegen, Provincie Gelderland, Netherlands
  • 2009–2011
    • University Hospital RWTH Aachen
      Aachen, North Rhine-Westphalia, Germany
  • 2006–2011
    • University Medical Center Utrecht
      • Department of Nephrology
      Utrecht, Provincie Utrecht, Netherlands
    • Amphia Ziekenhui
      Breda, North Brabant, Netherlands
  • 1998–2011
    • Canisius-Wilhelmina Ziekenhuis
      Nymegen, Gelderland, Netherlands
  • 2008
    • Slingeland Ziekenhuis
      Doetinchem, Gelderland, Netherlands
  • 2007
    • Universitair Medisch Centrum Groningen
      • Department of Internal Medicine
      Groningen, Groningen, Netherlands
  • 2003
    • Gelderse Vallei Hospital
      • Department of Internal Medicine
      Ede, Gelderland, Netherlands
  • 1992–1995
    • University of Colorado
      • Department of Medicine
      Denver, CO, United States
  • 1991
    • University of Colorado Hospital
      • Department of Medicine
      Denver, Colorado, United States