10 results on '"John D. Mahan"'
Search Results
2. Promoting bone health in children and adolescents following solid organ transplantation
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Ala K. Shaikhkhalil, Kirstin Kusumi, Hiren P. Patel, and John D. Mahan
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medicine.medical_specialty ,Adolescent ,Bone disease ,Population ,Psychological intervention ,Metabolic bone disease ,Quality of life ,Bone Density ,medicine ,Vitamin D and neurology ,Humans ,Healthy Lifestyle ,Vitamin D ,Child ,Intensive care medicine ,education ,Transplantation ,education.field_of_study ,Bone Density Conservation Agents ,business.industry ,medicine.disease ,Transplant Recipients ,Denosumab ,Dietary Supplements ,Pediatrics, Perinatology and Child Health ,Calcium ,Bone Diseases ,business ,Immunosuppressive Agents ,medicine.drug - Abstract
Solid organ transplantation in children and adolescents provides many benefits through improving critical organ function, including better growth, development, cardiovascular status, and quality of life. Unfortunately, bone status may be adversely affected even when overall status is improving, due to issues with pre-existing bone disease as well as medications and nutritional challenges inherent post-transplantation. For all children and adolescents, bone status entering adulthood is a critical determinant of bone health through adulthood. The overall health and bone status of transplant recipients benefits from attention to regular physical activity, good nutrition, adequate calcium, phosphorous, magnesium and vitamin D intake and avoidance/minimization of soda, extra sodium, and obesity. Many immunosuppressive agents, especially glucocorticoids, can adversely affect bone function and development. Minimizing exposure to "bone-toxic" medications is an important part of promoting bone health in children post-transplantation. Existing guidelines detail how regular monitoring of bone status and biochemical markers can help detect bone abnormalities early and facilitate valuable bone-directed interventions. Attention to calcium and vitamin D supplementation, as well as tapering and withdrawing glucocorticoids as early as possible after transplant, can provide best bone outcomes for these children. Dual-energy X-ray absorptiometry can be useful to detect abnormal bone mass and fracture risk in this population and newer bone assessment methods are being evaluated in children at risk for poor bone outcomes. Newer bone therapies being explored in adults with transplants, particularly bisphosphonates and the RANKL inhibitor denosumab, may offer promise for children with low bone mass post-transplantation.
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- 2020
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3. Nephrotic syndrome‐associated hypercoagulopathy is alleviated by both pioglitazone and glucocorticoid which target two different nuclear receptors
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Patrick D. Brophy, ML Chang, Katelyn J. Wolfgang, Keisha L. Gibson, Tarak Srivastava, Laurence Greenbaum, Melinda A. Chanley, Jiro Kino, William E. Smoyer, Bryce A. Kerlin, Amanda P. Waller, FM Iorember, Richard F. Ransom, Cynthia G. Pan, Denis F. Geary, Hiren P. Patel, Shipra Agrawal, and John D. Mahan
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Male ,medicine.medical_specialty ,Nephrotic Syndrome ,Physiology ,Nuclear Receptors ,030204 cardiovascular system & hematology ,Methylprednisolone ,lcsh:Physiology ,03 medical and health sciences ,Receptors, Glucocorticoid ,0302 clinical medicine ,Physiology (medical) ,Internal medicine ,Animals ,Humans ,Medicine ,Hypoalbuminemia ,Rats, Wistar ,Child ,Blood Coagulation ,Glucocorticoids ,Original Research ,Proteinuria ,Pioglitazone ,lcsh:QP1-981 ,business.industry ,Antithrombin ,Albumin ,Thrombosis ,medicine.disease ,Rats ,PPAR gamma ,Endocrinology ,Hypercoagulopathy ,Female ,medicine.symptom ,business ,Nephrotic syndrome ,030217 neurology & neurosurgery ,Glucocorticoid ,medicine.drug - Abstract
Background Thrombosis is a potentially life‐threatening nephrotic syndrome (NS) complication. We have previously demonstrated that hypercoagulopathy is proportional to NS severity in rat models and that pioglitazone (Pio) reduces proteinuria both independently and in combination with methylprednisolone (MP), a glucocorticoid (GC). However, the effect of these treatments on NS‐associated hypercoagulopathy remains unknown. We thus sought to determine the ability of Pio and GC to alleviate NS‐associated hypercoagulopathy. Methods Puromycin aminonucleoside‐induced rat NS was treated with sham, Low‐ or High‐dose MP, Pio, or combination (Pio + Low‐MP) and plasma was collected at day 11. Plasma samples were collected from children with steroid‐sensitive NS (SSNS) and steroid‐resistant NS (SRNS) upon presentation and after 7 weeks of GC therapy. Plasma endogenous thrombin potential (ETP), antithrombin (AT) activity, and albumin (Alb) were measured using thrombin generation, amidolytic, and colorimetric assays, respectively. Results In a rat model of NS, both High‐MP and Pio improved proteinuria and corrected hypoalbuminemia, ETP and AT activity (p, Acquired hypercoagulopathy contributes to thrombotic‐risk in patients with nephrotic syndrome. Here we show that treatments directed at reversing the glomerular filtration defect effectively reduce hypercoagulopathy in both animal models and childhood nephrosis. These data imply that effective treatment for nephrotic syndrome may simultaneously reduce thrombotic risk.
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- 2020
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4. De novotherapy with everolimus and reduced-exposure cyclosporine following pediatric kidney transplantation: A prospective, multicenter, 12-month study
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J. Mark Hexham, Robert B. Ettenger, Kevin C Mange, Carl M. Grushkin, and John D. Mahan
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Male ,medicine.medical_specialty ,Adolescent ,Basiliximab ,Biopsy ,Urology ,Renal function ,Drug Administration Schedule ,Adrenal Cortex Hormones ,medicine ,Humans ,Everolimus ,Prospective Studies ,Child ,Prospective cohort study ,Adverse effect ,Kidney transplantation ,Subclinical infection ,Sirolimus ,Transplantation ,business.industry ,medicine.disease ,Kidney Transplantation ,Surgery ,Treatment Outcome ,Research Design ,Child, Preschool ,Pediatrics, Perinatology and Child Health ,Cohort ,Cyclosporine ,Female ,business ,Immunosuppressive Agents ,Glomerular Filtration Rate ,medicine.drug - Abstract
Prospective data regarding the de novo use of everolimus following kidney transplantation in children are sparse. In a prospective, 12-month, single-arm, open-label study, pediatric kidney transplant patients received everolimus (target trough concentration ≥3 ng/mL) with reduced-exposure CsA and corticosteroids, with or without basiliximab induction. Sixteen of the 18 patients completed the study on-treatment. Age range was 2-16 yr (mean 10.9 yr); eight patients received a living donor graft. Mean (s.d.) everolimus level was 7.4 (3.1) ng/mL during the first 12 months post-transplant. There were no cases of BPAR, graft loss, or death during the study. Protocol biopsies were performed at month 12 in seven patients, with subclinical (untreated) acute rejection diagnosed in one case. Mean (s.d.) estimated GFR (Schwartz formula) was 98 (34) mL/min/1.73 m(2) at month 12. Three patients experienced one or more serious adverse events with a suspected relation to study medication. One patient discontinued study medication due to post-transplant lymphoproliferative disease (5.6%). Everolimus with reduced-dose CsA and corticosteroids achieved good efficacy and renal function and was well tolerated in this small cohort of pediatric kidney transplant patients. Controlled trials are required to answer remaining questions about the optimal use of everolimus in this setting.
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- 2012
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5. The role and future challenges for recombinant growth hormone therapy to promote growth in children after renal transplantation
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Halima S. Janjua and John D. Mahan
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Transplantation ,medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Immunosuppression ,Disease ,medicine.disease ,Short stature ,Clinical trial ,medicine ,Secondary hyperparathyroidism ,medicine.symptom ,Intensive care medicine ,business ,Kidney transplantation ,Kidney disease - Abstract
Chronic kidney disease can severely impair linear growth in children. For many children, growth improves after renal transplantation, but for some, growth velocity remains low and for others, catch-up growth is insufficient to compensate for the deficit imparted by renal disease in the preceding years. Inadequate final adult height after renal transplant is multifactorial and can adversely affect the quality of life (QOL), psychosocial development and long term prospects for these children as they grow into adulthood. Growth failure after renal transplant requires thorough evaluation and its management in renal transplant recipients can involve improved nutritional intake, correction of metabolic acidosis, treatment of secondary hyperparathyroidism, steroid-sparing immunosuppression and/or use of recombinant human growth hormone (rGH). Treatment with rGH after renal transplant has been evaluated by a limited number of clinical trials suggesting efficacy and safety for this treatment strategy. Several important clinical questions regarding rGH use in children post-renal transplant remain unanswered.
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- 2011
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6. Multicenter trial of everolimus in pediatric renal transplant recipients: Results at three year
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Peter-Friedrich Hoyer, Mark A. Mentser, Patrick Niaudet, R. Vandamme-Lombaerts, J. Mark Hexham, Robert B. Ettenger, John D. Mahan, Gisela Offner, Paul C. Grimm, Nicholas J. A. Webb, and Chantal Loirat
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Graft Rejection ,Male ,medicine.medical_specialty ,Adolescent ,Biopsy ,Gastroenterology ,Adrenal Cortex Hormones ,Internal medicine ,Multicenter trial ,medicine ,Humans ,Everolimus ,Child ,Prospective cohort study ,Kidney transplantation ,Antibacterial agent ,Sirolimus ,Transplantation ,business.industry ,Graft Survival ,medicine.disease ,Kidney Transplantation ,Surgery ,Regimen ,Treatment Outcome ,Tolerability ,Pediatrics, Perinatology and Child Health ,Cyclosporine ,Drug Therapy, Combination ,Female ,business ,Immunosuppressive Agents ,medicine.drug - Abstract
There are few prospective clinical trials of mTOR inhibitors (or proliferation signal inhibitors) combined with CNI inhibitors in de novo pediatric renal transplantation. Results reported here are from a multicenter, open-label study in de novo pediatric renal transplant patients (
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- 2008
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7. Population Pharmacokinetics of Amlodipine in Hypertensive Children and Adolescents
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John D. Mahan, Ronald J. Portman, Milap C. Nahata, and Joseph T. Flynn
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Male ,medicine.medical_specialty ,Adolescent ,Metabolic Clearance Rate ,Population ,Population pharmacokinetics ,Pharmacology ,Models, Biological ,Pharmacokinetics ,Internal medicine ,medicine ,Humans ,Pharmacology (medical) ,Amlodipine ,Child ,education ,Antihypertensive Agents ,Volume of distribution ,education.field_of_study ,business.industry ,Infant ,NONMEM ,Pharmacokinetic analysis ,Endocrinology ,Child, Preschool ,Hypertension ,Female ,business ,Dosing Frequency ,medicine.drug - Abstract
A population pharmacokinetic study was conducted in 74 hypertensive children (mean age 10.4 +/- 4.4 years [mean +/- SD]) receiving amlodipine (mean dose 0.17 +/- 0.13 mg/kg/d) chronically. Multiple blood samples were obtained from each subject to characterize amlodipine pharmacokinetics. Plasma amlodipine concentrations were determined by liquid chromatography/mass spectrophotometry with multiple-reaction monitoring detection. Population pharmacokinetic analysis was performed using NONMEM. Amlodipine concentrations were similar in subjects dosed either once or twice daily. Amlodipine pharmacokinetics were well described by a 1-compartment model with first-order absorption and elimination. For a subject at the population median weight (45 kg), predicted apparent clearances (CL/F) were 23.7 L/h for males and 17.6 L/h for females, and the apparent volume of distribution (V/F) was 25.1 L/kg. Dosing frequency did not appear to affect amlodipine concentrations in children. Weight-adjusted CL/F and V/F of amlodipine in younger children were significantly greater than in older children, suggesting a need for higher doses when treating young children with amlodipine.
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- 2006
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8. Learning management systems: technology to measure the medical knowledge competency of the ACGME
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C Erwin Johnson, John D. Mahan, Larry Hurtubise, Laura Plachta, Judy Groner, Julie Castrop, Douglas McLaughlin, Gina French, and Morissa Ladinsky
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Programmed Instructions as Topic ,Educational measurement ,Medical education ,business.industry ,education.educational_degree ,Graduate medical education ,Information technology ,General Medicine ,Pediatrics ,Habilitation ,Accreditation ,Education ,Humans ,Medicine ,Learning Management ,Clinical Competence ,Curriculum ,business ,education ,Competence (human resources) ,Computer-Assisted Instruction ,Education, Medical, Undergraduate - Abstract
Aims We report how the learning management system (LMS) Web Course Tools (WebCT) was used to design, implement and evaluate the web-based course ‘Principles of Ambulatory Paediatrics’, taken by paediatric residents during an ambulatory block rotation. This report also illustrates how WebCT can be used to measure the medical knowledge competency required by the Accreditation Council for Graduate Medical Education (ACGME). Methods Eighty paediatric residents completed a 1-month outpatient rotation between July 1, 2001 and June 30, 2002. During this rotation residents were required to complete 4 modules in asthma, otitis media, gastroenteritis and fever, respectively. Each module was evaluated using a standard questionnaire. Results Completion rates for the required modules ranged from 64−72%. Residents in all 3 years of training showed improvement between the pre- and post-test scores for each module, except for postgraduate Year 2 residents in the asthma module. Most residents somewhat agreed, agreed or strongly agreed that the module components were useful and that the experience of completing the modules would improve their ability to take care of patients. Conclusions The LMS WebCT is an innovative and adaptable approach for designing a web-based course for primary care education in paediatrics. The LMS addresses the educational needs of both a clinical division and a residency programme. The LMS also provides an information technology infrastructure to measure the medical knowledge competency required by the ACGME.
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- 2004
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9. Effects of Varying Voltage and Pulse Pattern during Electrical Immobilization of Adult Chum Salmon on Egg Survival to the Eyed Egg Stage
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Drew Aro, Deb Kucipeck, Andrea Hough Tesch, John D. Mahan, and Geoffrey Clark
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Pulse pattern ,Pulse (signal processing) ,Electrical shock ,Aquatic Science ,Biology ,biology.organism_classification ,Repetitive motion ,Fishery ,chemistry.chemical_compound ,Animal science ,medicine.anatomical_structure ,chemistry ,Carbon dioxide ,medicine ,%22">Fish ,Oncorhynchus ,Gamete - Abstract
Electrical shock is becoming widely used to immobilize adult salmon before gamete removal. Working with immobilized fish reduces repetitive motion injuries among workers and decreases staff requirements, but survival rates of eggs obtained from adults immobilized by electrical currents have varied. Eleven DC wave forms and voltage combinations were used to immobilize adult chum salmon Oncorhynchus keta, and survival rates of eggs taken from shocked fish were compared with survival rates from fish immobilized with carbon dioxide. Egg survival rates increased as voltage and pulse pattern intensity decreased. Similar egg survival rates were recorded for those obtained from the carbon dioxide controls (98%) and those obtained at the lower voltage and pulse patterns (96-98%), thus validating the use of electrical immobilization on adult chum salmon before gamete removal.
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- 1999
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10. Gentamicin-induced readthrough of stop codons in Duchenne muscular dystrophy
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Ricardo Bien-Willner, Wendy King, Vinod Malik, Majed Dasouki, Carmen Serrano-Munuera, Louise R. Rodino-Klapac, Janaiah Kota, Sarah Lewis, Richard J. Barohn, Kevin M. Flanigan, Christopher M. Walker, Katherine J. Campbell, Cheryl Wall, Victoria Watts, John D. Mahan, Brenda Banwell, John R. Hayes, Kumaraswamy Sivakumar, Zarife Sahenk, Roula al-Dahhak, Christopher Shilling, Jerry R. Mendell, and Laurence Viollet
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medicine.medical_specialty ,mdx mouse ,Time Factors ,Adolescent ,T-Lymphocytes ,Duchenne muscular dystrophy ,Enzyme-Linked Immunosorbent Assay ,Frameshift mutation ,Cohort Studies ,chemistry.chemical_compound ,Audiometry ,Internal medicine ,medicine ,Humans ,Muscular dystrophy ,Child ,Creatine Kinase ,Protein Synthesis Inhibitors ,Muscle Cells ,biology ,business.industry ,medicine.disease ,Virology ,Stop codon ,Exon skipping ,Ataluren ,Muscular Dystrophy, Duchenne ,Endocrinology ,Neurology ,chemistry ,Child, Preschool ,Mutation ,Codon, Terminator ,biology.protein ,Neurology (clinical) ,Gentamicins ,Dystrophin ,business - Abstract
Objective The objective of this study was to establish the feasibility of long-term gentamicin dosing to achieve stop codon readthrough and produce full-length dystrophin. Mutation suppression of stop codons, successfully achieved in the mdx mouse using gentamicin, represents an important evolving treatment strategy in Duchenne muscular dystrophy (DMD). Methods Two DMD cohorts received 14-day gentamicin (7.5mg/kg/day): Cohort 1 (n = 10) stop codon patients and Cohort 2 (n = 8) frameshift controls. Two additional stop codon DMD cohorts were gentamicin treated (7.5mg/kg) for 6 months: Cohort 3 (n = 12) dosed weekly and Cohort 4 (n = 4) dosed twice weekly. Pre- and post-treatment biopsies were assessed for dystrophin levels, as were clinical outcomes. Results In the 14-day study, serum creatine kinase (CK) dropped by 50%, which was not seen in frameshift DMD controls. After 6 months of gentamicin, dystrophin levels significantly increased (p = 0.027); the highest levels reached 13 to 15% of normal (1 in Cohort 3, and 2 in Cohort 4), accompanied by reduced serum CK favoring drug-induced readthrough of stop codons. This was supported by stabilization of strength and a slight increase in forced vital capacity. Pretreatment stable transcripts predicted an increase of dystrophin after gentamicin. Readthrough efficiency was not affected by the stop codon or its surrounding fourth nucleotide. In 1 subject, antigen-specific interferon-γ enzyme-linked immunospot assay detected an immunogenic dystrophin epitope. Interpretation The results support efforts to achieve drug-induced mutation suppression of stop codons. The immunogenic epitope resulting from readthrough emphasizes the importance of monitoring T-cell immunity during clinical studies that suppress stop codons. Similar principles apply to other molecular strategies, including exon skipping and gene therapy. ANN NEUROL 2010;67:771–780
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- 2010
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