David J Hobbs

Michigan State University, Ист-Лансинг, Michigan, United States

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Publications (9)19.78 Total impact

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    ABSTRACT: Objective To evaluate whether renal mass biopsy (RMB) biopsy location or number affected diagnostic accuracy in a prospective ex vivo study. Methods Three cores (1 central and 2 peripheral) were obtained for histologic processing from each of 48 renal masses after nephrectomy. Individual biopsy cores were evaluated independently for tumor subtype and grade by a single, blinded GU pathologist. Results Although individual biopsy cores were informative and confirmed accurate in only 59 % of samples, accuracy increased to 85 % with three-core biopsy (p < 0.01). Cancer identification with a single peripheral core increased to 77 % by adding a central core (p = 0.005), to 80 % with a second peripheral core (p = 0.008), and to 85 % with three cores (p = 0.001). Similarly, diagnostic yield for histologic subtyping increased from 44 % for 1-core biopsy to 59–63 % with 2-core biopsy (p = 0.03) and to 67 % with 3-core biopsy (p = 0.02). The correct subtype was confirmed at nephrectomy for 63 % of clear cell RCC, 60 % of papillary RCC, 100 % of chromophobe RCC and 75 % of oncocytomas. When recorded, nuclear grade corresponded to final grade assignment in 56 % and was within 1 grade in an additional 37 %. Conclusions RMB has not been used routinely in the evaluation of renal cortical neoplasms because of reportedly high rates of indeterminate or inaccurate diagnoses. In this prospective, ex vivo study, single-core RMB results in a low diagnostic yield. Obtaining multiple cores significantly improved diagnostic yield, with similar results with two-core and three-core RMB. We therefore recommend that RMB for suspicion of cancer include at least two peripheral cores.
    No preview · Article · Apr 2012 · World Journal of Urology
  • David J Hobbs · Jennifer McLellan · Marc G Schlatter
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    ABSTRACT: Diaphragmatic tumors are uncommon and difficult to diagnose in the pediatric population. Schwannoma is a benign, slow-growing peripheral nerve sheath tumor that is most commonly associated with the extremities in childhood. We herein report a schwannoma of the diaphragm in a pediatric patient and review the pediatric literature.
    No preview · Article · Apr 2012 · Journal of Pediatric Surgery
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    ABSTRACT: Megestrol acetate (MA) has been used to treat weight loss in pediatric patients with malignancies, cystic fibrosis and HIV/AIDS. We herein report our experience with MA in pediatric patients with chronic kidney disease (CKD). We conducted a retrospective cohort study. Charts were evaluated for clinical, treatment, and laboratory data at six time points: approximately 6 months prior to initiation of MA, at initiation and cessation of MA, and at 2-, 4-, and 8-month follow-up. Anthropometric measurements were corrected for age and sex by conversion to z scores. Division of Pediatric Nephrology, Helen DeVos Children's Hospital, Grand Rapids, MI. Pediatric patients (n = 25) with CKD and poor weight gain. Patients were administered MA at initial and tapered doses of 14.4 ± 8.1 mg/kg/d and 10.1 ± 6.5 mg/kg/d, respectively, for 5.4 ± 6.3 months. The study population (n = 25) was 60% male, 16% African American, 72% white, and 12% Hispanic with a mean ± SD age of 8.9 ± 5.4 years. Prior to MA therapy, patients demonstrated a decrease in BMI and poor weight gain. The treatment phase was associated with significant increases in BMI (P < .0001) and weight (P < .0001), which were well sustained at 8-month follow-up (P < 0.01 and P < 0.001, respectively). Patients demonstrated continued increases in height. A single patient exhibited physical adverse side effects (cushingoid features) associated with MA; otherwise, MA was well tolerated. MA appears to effectively improve weight gain in pediatric CKD patients with minimal adverse side effects and may therefore serve as a safe, short-term, nutritional strategy.
    No preview · Article · Nov 2010 · Journal of Renal Nutrition
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    Full-text · Article · Apr 2010 · Pediatric Nephrology
  • D J Hobbs · G-M Barletta · J Y Chung · T E Bunchman
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    ABSTRACT: Sarcoidosis is a multisystem disease of unknown etiology primarily affecting the lungs, skin, and lymph nodes. The disease usually manifests in young adults and is uncommon in childhood. Renal involvement, including granulomatous interstitial nephritis (GIN), is rare, and few cases of isolated sarcoid GIN have been reported in pediatrics. We report a case and review the literature.
    No preview · Article · Nov 2009 · Clinical nephrology
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    ABSTRACT: Recent data suggest that elevated levels of uric acid (UA) might contribute to the progression of renal disease. Rasburicase, recombinant urate oxidase, is a highly safe and efficacious hypo-uricosuric agent for treatment of elevated UA levels from tumor lysis. We adopted the use of rasburicase for management of hyperuricemia in infants with acute kidney injury (AKI) and, herein, report our experience. We conducted a retrospective chart review of infants with hyperuricemia (UA > 8 mg/dl) secondary to AKI (serum creatinine > 1.5 mg/dl) treated with rasburicase. Seven infants (mean age 34 +/- 55 days, six male), with a mean weight of 3.2 +/- 1.2 kg, were identified. Rasburicase was administered intravenously as a single, onetime, bolus of 0.17 +/- 0.04 mg/kg body weight. Within 24 h, serum UA had decreased from 13.6 +/- 4.5 mg/dl to 0.9 +/- 0.6 mg/dl (P < 0.05), creatinine had decreased from 3.2 +/- 2.0 mg/dl to 2.0 +/- 1.2 mg/dl (P < 0.05), and urinary output had increased from 2.4 +/- 1.2 ml/kg per hour to 5.9 +/- 1.8 ml/kg per hour (P < 0.05). Continued improvements in UA, creatinine, and urinary output were observed in the week following administration of rasburicase, without rebound of the UA. We observed no treatment-related side effects. All patients demonstrated a normalization of uric acid level without need of renal replacement therapy. In conclusion, a single intravenously administered bolus of rasburicase appears to be a novel treatment for hyperuricemia in infants with AKI.
    No preview · Article · Nov 2009 · Pediatric Nephrology
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    ABSTRACT: This study sought to evaluate the use of adult renal formulas in hyperkalemic infants with chronic kidney disease (CKD). This was a retrospective, single-center cohort study. This study took place at the Department of Pediatric Nephrology, Dialysis, and Transplantation at Helen DeVos Children's Hospital (Grand Rapids, MI). Seven hyperkalemic infants (mean age, 6.9 months) comprised the study population: 29% with stage 3 CKD, 29% with stage 4 CKD, and 42% with stage 5 CKD. Infants were empirically treated with adult renal formulas for an average duration of 9.6 months. Six of seven infants were started on breast milk or infant formula (Similac PM 60/40, Abbott Laboratories, Columbus, OH), but because of inadequate growth and hyperkalemia, were transitioned to adult renal formulas (Suplena, Abbott Laboratories, Columbus, OH; Nepro, Abbott Laboratories, Columbus, OH; and/or Renalcal, Nestle Nutrition, Minnetonka, MN). One infant received adult renal formula at birth. The outcome measures included amount of potassium delivered by infant and adult renal formulas, level of serum potassium, and anthropometric measurements adjusted for age and gender (z-scores). The transition from infant to adult renal formula resulted in a decrease in mean amount of potassium delivered by formula (from 2.6 to 1.0 mEq/kg/day, P < .001) and a decrease in mean serum potassium (from 5.1 to 4.0 mmol/L, P < .01). During treatment with adult renal formula, the infants demonstrated a significant increase in mean weight z-score (from -1.0 to 0.5, P < .01), height z-score (from -1.9 to -0.5, P < .01), and head-circumference z-score (from -1.5 to -1.0, P=.03). Adult renal formulas were well-tolerated. Hyperkalemic infants with CKD can be nutritionally managed on adult renal formula.
    No preview · Article · Oct 2009 · Journal of Renal Nutrition
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    ABSTRACT: Paediatric patients with systemic lupus erythematosus (SLE) often have severe presentations including lupus nephritis (LN). Few paediatric studies have evaluated the anticardiolipin antibody (aCL) and renal histology. The purpose of this study was to evaluate clinicopathologic features, including aCL, short-term clinical and renal histologic outcomes of paediatric patients with new-onset SLE nephritis. We conducted a single centre, retrospective inception cohort study. Charts were reviewed at presentation (initial renal biopsy), 6-month (follow-up biopsy) and 12-month follow-up. The population consisted of 21 patients (median age, 14.5 years): 19/21 were female, 6/21 African American, 3/21 Asian, 9/21 Caucasian and 3/21 Hispanic. At presentation, 19/21 had elevated aCL, 15/21 hypertensive, 12/21 nephrotic and 7/21 required haemodialysis (HD)-2/7 HD patients had thrombotic microangiopathy, 1/7 crescentic glomerulonephritis. Two patients had thromboembolism: both had aCL, were taking oral contraceptives and required HD, one was nephrotic and the other had elevated lupus anticoagulant. Initial biopsies revealed 6/21 ISN/RPS class II nephritis, 3/21 class III, 7/21 class IV and 5/21 class V. Treatment consisted of methylprednisolone, corticosteroids, cyclophosphamide or mycophenolate mofetil. Follow-up biopsies revealed 12/13 to have improved histology. Indication for a follow-up biopsy was severe illness at presentation. At 12-month follow-up, no patients were nephrotic (P < 0.001) or required HD (P < 0.001), and 3/14 had elevated aCL (P < 0.001). Elevated aCL, hypertension, nephrotic syndrome and need for HD were common presentations among our paediatric SLE nephritis population. Renal histology and aCL were helpful in the therapeutic management.
    Full-text · Article · Sep 2009 · Nephrology Dialysis Transplantation
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    ABSTRACT: Renovascular hypertension from renal artery aneurysmal formation is a rare complication of fibromuscular dysplasia. Few data exist to direct the management of intrarenal artery aneurysms in pediatric patients. We report the presentation, diagnosis and management of renovascular hypertension and intrarenal aneurysmal disease in a preschool child.
    No preview · Article · Jun 2009 · Pediatric Radiology