James C Barton

University of Alabama at Birmingham, Birmingham, Alabama, United States

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Publications (228)1101.47 Total impact


  • No preview · Article · Feb 2016 · Hepatology
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    ABSTRACT: Background: We sought to identify risk factors for insulin resistance, metabolic syndrome (MetS), and diabetes mellitus in 248 non-Hispanic white HFE C282Y homozygotes identified by population screening. Methods: We analyzed observations obtained prospectively in a postscreening examination: age; sex; body mass index (BMI); systolic/diastolic blood pressure; metacarpophalangeal (MP) joint hypertrophy; hepatomegaly; complete blood counts; alanine/aspartate aminotransferase levels; elevated C-reactive protein (>0.5 mg/dL); transferrin saturation; serum ferritin; homeostasis model assessment-insulin resistance (HOMA-IR); and MetS. Results: Twenty-six participants (10.5%) had diabetes diagnoses. A significant trend across HOMA-IR quartiles was observed only for blood neutrophils. Logistic regression on HOMA-IR fourth quartile revealed positive associations: age (P = 0.0002); male sex (P = 0.0022); and BMI (P < 0.0001). HOMA-IR fourth quartile predicted MetS (P < 0.0001). Logistic regression on diabetes revealed positive associations: age (P = 0.0012); male sex (P = 0.0068); MP joint hypertrophy (P = 0.0167); neutrophils (P = 0.0342); and MetS (P = 0.0298). Serum ferritin did not predict HOMA-IR fourth quartile, MetS, or diabetes. Conclusions: In screening C282Y homozygotes, age, male sex, and BMI predicted HOMA-IR fourth quartile. HOMA-IR fourth quartile alone predicted MetS. Diabetes was associated with greater age, male sex, MP joint hypertrophy, greater blood neutrophil counts, and MetS.
    No preview · Article · Jan 2016 · Metabolic syndrome and related disorders
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    James C. Barton · J. Clayborn Barton · Luigi F. Bertoli
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    ABSTRACT: Reports of pica for uncooked rice (ryzophagia) in adults who reside in European and derivative countries are uncommon. We evaluated and treated two nonpregnant women with pica for uncooked basmati rice. Both women reported fatigue, abdominal discomfort after consuming large quantities of uncooked basmati rice, and hair loss. One woman was from India and the other was from Pakistan. Both women were vegetarians. Basmati was the local rice in their native countries and their usual rice in the USA. Both women had tooth damage due to eating uncooked rice and iron deficiency with microcytic anemia attributed to menorrhagia and multiparity. Ryzophagia and other manifestations (except tooth damage) resolved after iron dextran therapy. We review and discuss other reports of ryzophagia associated with iron deficiency, pregnancy, race/ethnicity, geographic origin, and local traditions. We conclude that adults with ryzophagia in European and derivative countries are likely to be non-Europeans.
    Preview · Article · Jan 2016 · Case Reports in Medicine

  • No preview · Article · Dec 2015 · Hepatology
  • James C Barton · Corwin Q Edwards · Ronald T Acton
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    ABSTRACT: The hemochromatosis gene HFE was discovered in 1996, more than a century after clinical and pathologic manifestations of hemochromatosis were reported. Linked to the major histocompatibility complex (MHC) on chromosome 6p, HFE encodes the MHC class I-like protein HFE that binds beta-2 microglobulin. HFE influences iron absorption by modulating the expression of hepcidin, the main controller of iron metabolism. Common HFE mutations account for ~90% of hemochromatosis phenotypes in whites of western European descent. We review HFE mapping and cloning, structure, promoters and controllers, and coding region mutations, HFE protein structure, cell and tissue expression and function, mouse Hfe knockouts and knockins, and HFE mutations in other mammals with iron overload. We describe the pertinence of HFE and HFE to mechanisms of iron homeostasis, the origin and fixation of HFE polymorphisms in European and other populations, and the genetic and biochemical basis of HFE hemochromatosis and iron overload.
    No preview · Article · Oct 2015 · Gene
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    James C. Barton · J. Clayborn Barton
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    ABSTRACT: We performed a retrospective study of autoimmune conditions (ACs) in 235 hemochromatosis probands at diagnosis by analyzing age, sex, ACs, history of first-degree family members with ACs (FH), diabetes, heavy ethanol consumption, elevated serum ALT/AST, nonalcoholic fatty liver disease, viral hepatitis, cirrhosis, iron removed to achieve iron depletion (QFe), and positivity for human leukocyte antigen (HLA) haplotypes A ∗ 01 , B ∗ 08 ; A ∗ 02 , B ∗ 44 ; A ∗ 03 , B ∗ 07 ; A ∗ 03 , B ∗ 14 ; and A ∗ 29 , B ∗ 44 . There were 138 men (58.7%). Median followup was 19.6 y. One or more of 19 ACs were diagnosed in each of 35 probands (14.9%). Prevalences of Hashimoto’s thyroiditis, rheumatoid arthritis, and ankylosing spondylitis were 8.1% (95% CI: [5.1, 12.5]), 1.7% [0.6, 4.6], and 0.0085 [0.0015, 0.0337], respectively. Eighteen probands (7.7%) had a FH. Eight probands with ACs had 9 family members with ACs. In a logistic regression, ACs were less likely in men (odds ratio (OR) 0.3 [0.1, 0.6]) and more likely in probands with a FH (OR 4.1 [1.4, 11.8]). Overall ACs risk was not significantly associated with QFe or HLA haplotypes. Estimated survival of probands with and without ACs did not differ significantly. We conclude that ACs are common in hemochromatosis probands, especially women and probands with a FH.
    Preview · Article · Oct 2015 · Journal of Immunology Research
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    ABSTRACT: We characterized 121 adults with frequent or severe bacterial respiratory tract infections at diagnosis of selective subnormal IgG3. Mean age was 47±13 (SD)y; 87.6% were women. Associated disorders included: autoimmune conditions 33.1%; hypothyroidism 14.9%; atopy 29.8%; and other allergy manifestations 41.3%. In 34.1%, proportions of protective Streptococcus pneumoniae serotype-specific IgG levels did not increase after polyvalent pneumococcal polysaccharide vaccination. Blood CD19+, CD3+/CD4+, CD3+/CD8+, and CD56+/CD16+ lymphocyte levels were within reference limits in most patients. In regression analyses, independent variables age; sex; autoimmune conditions; hypothyroidism; atopy; allergy manifestations; corticosteroid therapy; and lymphocyte subsets were not significantly associated with IgG subclass, IgA, or IgM levels. Frequencies of HLA haplotypes A*01, B*08; A*02, B*14; A*02, B*15; A*02, B*44; A*02, B*57; and A*03, B*07 were greater in 80 patients than 751 controls. We conclude that subnormal IgG3 and non-protective S. pneumoniae IgG levels contribute to increased susceptibility to respiratory tract infections.
    No preview · Article · Sep 2015 · Cellular Immunology

  • No preview · Article · Sep 2015 · Hepatology
  • Paul C Adams · James C Barton · Helen Guo · David Alter · Mark Speechley
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    ABSTRACT: We identified no reports of long-term follow-up of participants in hemochromatosis screening programs. We evaluated causes of death and survival in non-C282Y homozygous Canadian participants in the primary care-based hemochromatosis and iron overload screening (HEIRS) study. Initial screening (IS) included transferrin saturation (TS), serum ferritin (SF), HFE genotyping (C282Y, H63D), and health questionnaire responses. By definition, participants without C282Y or H63D had HFE wt/wt. We linked 20,306 Canadian participants to the Ontario Death Registry for dates and causes of death 9 y after IS. We computed Cox proportional hazards to identify factors with increased death risks and Kaplan-Meier curves to estimate survival of non-C282Y homozygous participants with SF ≤ 1,000 μg/L and > 1,000 μg/dL. There were 19,052 evaluable participants (IS mean age 49 y; 60% women; 93 C282Y homozygotes). There were 988 deaths. Significantly increased hazard ratios for all-cause mortality were positively associated with TS, SF, men, and C282Y homozygosity, and liver disease, diabetes, and heart failure reports. Non-C282Y homozygous participants with SF > 1,000 μg/L had lower survival than those with SF ≤ 1,000 μg/L (p < 0.0001). Nine years after initial screening, non-C282Y homozygous participants and SF > 1,000 μg/L was associated with decreased survival.
    No preview · Article · Apr 2015 · Annals of hepatology: official journal of the Mexican Association of Hepatology
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    ABSTRACT: To identify polymorphisms associated with variability of iron overload severity in HFE-associated hemochromatosis, we performed exome sequencing of DNA from 35 male HFE C282Y homozygotes with either markedly increased iron stores (n=22; cases) or with normal or mildly increased iron stores (n=13; controls). The 35 participants, residents of the U.S., Canada, and Australia, reported no or light alcohol consumption. Sequencing data included 82,068 single nucleotide variants, and 10,337 genes were tested for a difference between cases and controls. A variant in the GNPAT gene showed the most significant association with severe iron overload (p = 3x10(-6) , p=0.033 by the likelihood ratio test after correction for multiple comparisons). Sixteen of 22 participants with severe iron overload had GNPAT polymorphism p.D519G (rs11558492) (15 heterozygotes, one homozygote). No control participant had this polymorphism. To examine functional consequences of GNPAT deficiency, we performed siRNA-based knockdown of GNPAT in the human liver-derived cell line HepG2/C3A. This knockdown resulted in a >17-fold decrease in expression of the mRNA encoding the iron regulatory hormone hepcidin. Conclusion: GNPAT p.D519G is associated with a high-iron phenotype in HFE C282Y homozygotes and may participate in hepcidin regulation. This article is protected by copyright. All rights reserved. Copyright © 2015 American Association for the Study of Liver Diseases.
    Full-text · Article · Jan 2015 · Hepatology
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    ABSTRACT: Primary iron overload in African Americans has been reported predominantly from autopsy studies. We characterized hepatic iron phenotypes in 83 African Americans who underwent liver biopsy during the interval 1990 to 1995. We tabulated pathology report form data, iron grades in hepatocytes (0-4) and Kupffer cells (0-3) and abnormal liver histology. Increased iron was defined as hepatocyte or Kupffer iron grades ≥2, respectively. Heavy iron was defined as hepatocyte iron grade 3 or 4. Primary iron overload was defined as the presence of grade 3 or 4 hepatocellular iron in the absence of evidence of chronic alcohol effect, viral hepatitis, steatosis, unexplained inflammation, chronic erythrocyte transfusion or chronic ingestion of iron supplements. There were 37 men and 46 women (mean age: 53 ± 15 [SD] years). We observed heavy ethanol consumption, 12.0%; viral hepatitis, 26.5%; steatosis without heavy ethanol consumption, 43.4%; inflammation, 45.6%; fibrosis, 26.2% and bridging fibrosis/cirrhosis, 29.4%. Logistic regression on bridging fibrosis/cirrhosis revealed positive associations with heavy ethanol consumption (P = 0.0410) and viral hepatitis (P = 0.0044). The 22 patients (26.5%) with increased iron had greater mean age, proportion of men and heavy ethanol consumption. Five patients had heavy iron staining, among whom were 3 women (mean age: 54 years) with primary iron overload. Two of the 3 women had cirrhosis and diabetes mellitus. Among 83 adult African Americans who underwent liver biopsy, 3.6% had hepatic iron phenotypes consistent with primary iron overload.
    Preview · Article · Jan 2015 · The American Journal of the Medical Sciences
  • Ronald T Acton · J Clayborn Barton · James C Barton
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    ABSTRACT: Background: In some reports, serum ferritin (SF) has been associated with insulin resistance and metabolic syndrome. Methods: We studied non-Hispanic whites without diabetes mellitus in a postscreening examination. Participants included cases [HFE C282Y homozygosity; and transferrin saturation (TS) >50% and SF >300 μg/L (males) and TS >45% and SF >200 μg/dL (females), regardless of HFE genotype] and controls [HFE wild-type (wt/wt) and TS/SF 25th-75th percentiles]. We excluded participants with overnight fasts <8 hr, cirrhosis, hepatitis B or C, pregnancy, or missing data. Observations were age, sex, C282Y homozygosity, body mass index (BMI), systolic and diastolic blood pressures (SBP, DBP), lymphocytes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), C-reactive protein (CRP), TS, SF, and glucose/insulin. Insulin resistance was defined as homeostasis model assessment of insulin resistance (HOMA-IR) 4th quartile (≥2.70). Results: A total of 407 women and 362 men (mean age 54 years) included 188 C282Y homozygotes and 371 wt/wt. Significant trends across HOMA-IR quartiles included age, male sex, BMI, SBP, DBP, lymphocytes, ALT, CRP >0.5 mg/dL (positive), and TS (negative). Multiple regression on HOMA-IR revealed significant associations with male sex, BMI, SBP, lymphocytes, ALT, CRP>0.5 mg/dL (positive), and DBP and SF (negative). Logistic regression on HOMA-IR 4th quartile revealed significant positive associations with age, male sex, BMI, and lymphocytes. Metabolic syndrome occurred in 53 participants (6.9%). Logistic regression on metabolic syndrome revealed these odds ratios: HOMA-IR 4th quartile [9.1 (4.8, 17.3)] and CRP >0.5 mg/dL [2.9 (1.6, 5.4)]. Conclusions: Age, male sex, BMI, and lymphocytes were positively associated with HOMA-IR after correction for other factors. HOMA-IR 4th quartile and CRP >0.5 mg/dL predicted metabolic syndrome.
    No preview · Article · Nov 2014 · Metabolic Syndrome and Related Disorders
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    ABSTRACT: Background Our informal observations suggested that some patients with acute sensorineural hearing loss (ASNHL) have subnormal serum immunoglobulin (Ig) levels. We evaluated 28 consecutive adults (18 men, 10 women) at ASNHL diagnosis using: antibodies to 68 kD protein, 30 kD protein, and type II collagen; and serum total IgG, IgG subclasses, total IgA, and IgM. Reference ranges for Ig levels were mean¿±¿2 SD. We compared prevalences of subnormal IgG subclasses to those in 275 healthy European adults in previous reports. We also reviewed charts of consecutive adult index patients with primary Ig deficiency (35 common variable immunodeficiency, 406 IgG subclass deficiency) to identify other patients with probable ASHNL.ResultsMean age was 53¿±¿10 (SD) y. Six patients (21.4%) had other autoimmunity manifestations. Antibodies to 68 kD protein, 30 kD protein, and type II collagen were detected in 21.4% (6/28), 21.1% (4/19) and 18.8% (3/16), respectively. Three patients (10.7%) had subnormal IgG1, six (21.4%) had subnormal IgG3, and four (14.3%) had subnormal IgG1 and IgG3. Some had subnormal IgG2, IgG4, IgA, and IgM (n¿=¿1, 2, 3, and 1, respectively). Prevalences of subnormal IgG1 or IgG3 were greater in ASNHL patients (25.0% and 35.7%) than 275 controls (2.1% and 3.3%), respectively (p¿<¿0.0001, each comparison). Relative risks of subnormal IgG1 and IgG3 in ASNHL were 11.5 [95% CI: 4.1, 31.7] and 10.9 [4.8, 25.6], respectively. Hearing improved after initial therapy in 17 patients (60.7%). Multiple regressions on Ig levels revealed no significant associations with other available variables. Logistic regressions on initial therapy response revealed a positive association with men (p¿=¿0.0392) and a negative association with IgA (p¿=¿0.0274). Our estimated prevalence of probable ASNHL in 35 patients with common variable immunodeficiency during a follow-up interval of 8¿±¿4 y was 0% [95% CI: 0, 12.3%]). Prevalence of probable ASNHL in 406 patients with IgG subclass deficiency during the same interval was 0.74% [0.19, 2.33].Conclusions Serum levels of IgG1 or IgG3 were subnormal in 46.4% of 28 patients with ASNHL. Among adults who present with primary Ig deficiency, some may have or later develop ASNHL.
    Preview · Article · Oct 2014 · BMC Immunology
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    James C Barton · Luigi F Bertoli · J Clayborn Barton
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    ABSTRACT: Common variable immunodeficiency (CVID) and immunoglobulin (Ig) G subclass deficiency (IgGSD) are heterogeneous disorders characterized by respiratory tract infections, selective Ig isotype deficiencies, and impaired antibody responses to polysaccharide antigens. Using univariable analyses, we compared observations in 34 CVID and 398 IgGSD adult index patients (81.9% women) referred to a hematology/oncology practice. Similarities included specialties of referring physicians, mean ages, proportions of women, reactivity to Pneumovax, median serum IgG3 and IgG4 levels, median blood CD56+/CD16+ lymphocyte levels, positivity for HLA-A and -B types, and frequencies of selected HLA-A, -B haplotypes. Dissimilarities included greater prevalence of autoimmune conditions, lower median IgG, IgA, and IgM, and lower median CD19+, CD3+/CD4+, and CD3+/CD8+ blood lymphocytes in CVID patients. Prevalence of Sjögren's syndrome and hypothyroidism was significantly greater in CVID patients. Combined subnormal IgG1/IgG3 occurred in 59% and 29% of CVID and IgGSD patients, respectively. Isolated subnormal IgG3 occurred in 121 IgGSD patients (88% women). Logistic regression on CVID (versus IgGSD) revealed a significant positive association with autoimmune conditions and significant negative associations with IgG1, IgG3, and IgA and CD56+/CD16+ lymphocyte levels, but the odds ratio was increased for autoimmune conditions alone (6.9 (95% CI 1.3, 35.5)).
    Preview · Article · Sep 2014 · Research Journal of Immunology
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    ABSTRACT: Hereditary Hemochromatosis (HH) is a recessively inherited disorder of iron overload occurring commonly in subjects homozygous for the C282Y mutation in HFE gene localized on chromosome 6p21.3 in linkage disequilibrium with the human leukocyte antigen (HLA)-A locus. Although its genetic homogeneity, the phenotypic expression is variable suggesting the presence of modifying factors. One such genetic factor, a SNP microhaplotype named A-A-T, was recently found to be associated with a more severe phenotype and also with low CD8(+)T-lymphocyte numbers. The present study aimed to test whether the predictive value of the A-A-T microhaplotype remained in other population settings. In this study of 304 HH patients from 3 geographically distant populations (Porto, Portugal 65; Alabama, USA 57; Nord-Trøndelag, Norway 182), the extended haplotypes involving A-A-T were studied in 608 chromosomes and the CD8(+) T-lymphocyte numbers were determined in all subjects. Patients from Porto had a more severe phenotype than those from other settings. Patients with A-A-T seemed on average to have greater iron stores (p = 0.021), but significant differences were not confirmed in the 3 separate populations. Low CD8(+) T-lymphocytes were associated with HLA-A*03-A-A-T in Porto and Alabama patients but not in the greater series from Nord-Trøndelag. Although A-A-T may signal a more severe iron phenotype, this study was unable to prove such an association in all population settings, precluding its use as a universal predictive marker of iron overload in HH. Interestingly, the association between A-A-T and CD8(+) T-lymphocytes, which was confirmed in Porto and Alabama patients, was not observed in Nord-Trøndelag patients, showing that common HLA haplotypes like A*01-B*08 or A*03-B*07 segregating with HFE/C282Y in the three populations may carry different messages. These findings further strengthen the relevance of HH as a good disease model to search for novel candidate loci associated with the genetic transmission of CD8(+) T-lymphocyte numbers.
    Full-text · Article · Nov 2013 · PLoS ONE
  • James C Barton

    No preview · Article · Nov 2013 · The American Journal of the Medical Sciences
  • James C Barton · J Clayborn Barton

    No preview · Article · Sep 2013 · The journal of vascular access
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    James C Barton · J Clayborn Barton · Ronald T Acton
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    ABSTRACT: Objective We sought to identify predictors of diabetes diagnosed before hemochromatosis.Research Design and Methods We studied these 16 variables in 159 non-screening hemochromatosis probands with HFE C282Y homozygosity: age; sex; body mass index (BMI); diabetes reports in first-degree family members (dichotomous); heavy ethanol consumption; cigarette smoking; elevated serum ALT/AST levels; non-alcoholic fatty liver; chronic viral hepatitis; cirrhosis; hand arthropathy; iron removed by phlebotomy; and positivity for HLA-A*01, B*08; A*03, B*07; and A*03, B*14 haplotypes. We performed univariable and multivariable analyses.ResultsTwenty-three probands (14.5%) had diabetes; 19 were men. Each of the 23 probands had type 2 diabetes. Mean BMI was greater in probands with diabetes (31.7 ± 8.5 (SD) kg/m(2) vs. 27.6 ± 5.1 kg/m(2); p = 0.032). Reports of any first-degree family member with diabetes were more prevalent in probands with than in probands without diabetes (69.6% vs. 17.6%; p <0.0001). In probands with diabetes, the odds ratio (OR) of maternal diabetes was 6.7 ((95% CI 2.3, 19.7); p = 0.0005) and of sibling diabetes was 11.7 ((95% CI 3.0, 45.5); p = 0.0004). In a logistic regression model, predictors of diabetes at hemochromatosis diagnosis in 159 probands were diabetes reports in family members (OR 8.5 (95% CI 2.9, 24.8); p<0.0001) and BMI (OR 1.1 (1.0, 1.2); p=0.049). This model explained 26.0% of total deviance contributing to diabetes.Conclusions In non-screening hemochromatosis probands with HFE C282Y homozygosity, a heritable factor(s) increases the risk of diabetes diagnosed before hemochromatosis.
    Preview · Article · Aug 2013 · Diabetes care
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    ABSTRACT: Many patients referred for an elevated serum ferritin level <1000 µg⁄L are advised that they likely have iron overload and hemochromatosis. To determine the prevalence of HFE mutations in the hemochromatosis gene for 11 serum ferritin concentration intervals from 200 µg⁄L to 1000 µg⁄L in Caucasian participants in a primary care, population-based study. The Hemochromatosis and Iron Overload Screening study screened 99,711 participants for serum ferritin levels, transferrin saturation and genetic testing for the C282Y and H63D mutations of the HFE gene. This analysis was confined to 17,160 male and 27,465 female Caucasian participants because the HFE C282Y mutation is rare in other races. Post-test likelihood was calculated for prediction of C282Y homozygosity from a ferritin interval. A subgroup analysis was performed in participants with both an elevated serum ferritin level and transferrin saturation. There were 3359 male and 2416 female participants with an elevated serum ferritin level (200 µg⁄L to 1000 µg⁄L for women, 300 µg⁄L to 1000 µg⁄L for men). There were 69 male (2.1%) and 87 female (3.6%) C282Y homozygotes, and the probability of being a homozygote increased as the ferritin level increased. Post-test likelihood values were 0.3% to 16% in men and 0.3% to 30.4% in women. Iron loading HFE mutations are unlikely to be the most common cause of an elevated serum ferritin level in patients with mild hyperferritinemia. Patients should be advised that there are many causes of an elevated serum ferritin level including iron overload.
    No preview · Article · Jul 2013

  • No preview · Article · May 2013 · American Journal of Hematology

Publication Stats

5k Citations
1,101.47 Total Impact Points

Institutions

  • 1978-2015
    • University of Alabama at Birmingham
      • • Department of Medicine
      • • Department of Microbiology
      • • Department of Pediatrics
      • • Department of Obstetrics and Gynecology
      • • Division of Hematology / Oncology
      Birmingham, Alabama, United States
  • 2013
    • University of California, Irvine
      • Department of Medicine
      Irvine, California, United States
  • 2004
    • The Scripps Research Institute
      • Department of Molecular and Experimental Medicine
      La Jolla, CA, United States
  • 2000
    • Saint Louis University
      • Division of Gastroenterology & Hepatology
      Сент-Луис, Michigan, United States
  • 1978-1987
    • University of Alabama
      Tuscaloosa, Alabama, United States
  • 1986
    • United States Department of Veterans Affairs
      Бедфорд, Massachusetts, United States
  • 1981
    • University of Alabama Medical Center
      Birmingham, Alabama, United States