Lee Ann MacMillan-Crow

University of Arkansas at Little Rock, Little Rock, Arkansas, United States

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Publications (51)211.12 Total impact

  • Clark R Sims, Lee Ann MacMillan-Crow, Philip R Mayeux
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    ABSTRACT: Sepsis-induced acute kidney injury (SAKI) is a frequent complication of infant sepsis, which approximately doubles the mortality rate. The poor prognosis of these patients is a result of care that is mainly supportive, non-targeted and usually begun only after symptoms of the systemic inflammatory response syndrome are present.(1) Preclinical studies from relevant rodent models of SAKI suggest that mitochondria-targeted antioxidants may be a new mode of therapy that could actually promote recovery.Clinical Pharmacology & Therapeutics (2014); Accepted article preview online 22 August 2014; doi:10.1038/clpt.2014.170.
    Clinical Pharmacology &#38 Therapeutics 08/2014; 96(6). DOI:10.1038/clpt.2014.170 · 7.39 Impact Factor
  • Naeem K Patil, Nirmala Parajuli, Lee Ann Macmillan-Crow, Philip R Mayeux
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    ABSTRACT: Acute kidney injury (AKI) is a complication of sepsis and leads to a high mortality rate. Human and animal studies suggest that mitochondrial dysfunction plays an important role in sepsis-induced multi-organ failure; however, the specific mitochondrial targets damaged during sepsis remain elusive. We used a clinically relevant cecal ligation and puncture (CLP) murine model of sepsis and assessed renal mitochondrial function using high-resolution respirometry, renal microcirculation using intravital microscopy and renal function. CLP caused a time-dependent decrease in mitochondrial complex I and II/III respiration and reduced ATP. By 4 hours after CLP, activity of manganese superoxide dismutase (MnSOD) was decreased by 50% and inhibition was sustained through 36 hours. These events were associated with increased mitochondrial superoxide generation. We then evaluated whether the mitochondria-targeted antioxidant Mito-TEMPO could reverse renal mitochondrial dysfunction and attenuate sepsis-induced AKI. Mito-TEMPO (10 mg/kg) given at 6 hours post CLP decreased mitochondrial superoxide levels, protected complex I and II/III respiration, and restored MnSOD activity by 18 hours. Mito-TEMPO also improved renal microcirculation and glomerular filtration rate. Importantly, even delayed therapy with a single dose of Mito-TEMPO significantly increased 96-hour survival rate from 40% in untreated septic mice to 80%. Thus, sepsis causes sustained inactivation of three mitochondrial targets that can lead to increased mitochondrial superoxide. Importantly, even delayed therapy with Mito-TEMPO alleviated kidney injury, suggesting that it may be a promising approach to treat septic AKI.
    AJP Renal Physiology 02/2014; 306(7). DOI:10.1152/ajprenal.00643.2013 · 4.42 Impact Factor
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    ABSTRACT: Superoxide is widely regarded as the primary reactive oxygen species (ROS) which initiates downstream oxidative stress. Increased oxidative stress contributes, in part, to many disease conditions such as cancer, atherosclerosis, ischemia/reperfusion, diabetes, aging, and neurodegeneration. Manganese superoxide dismutase (MnSOD) catalyzes the dismutation of superoxide into hydrogen peroxide which can then be further detoxified by other antioxidant enzymes. MnSOD is critical in maintaining the normal function of mitochondria, thus its inactivation is thought to lead to compromised mitochondria. Previously, our laboratory observed increased mitochondrial biogenesis in a novel kidney-specific MnSOD knockout mouse. The current study used transient siRNA mediated MnSOD knockdown of normal rat kidney (NRK) cells as the in vitro model, and confirmed functional mitochondrial biogenesis evidenced by increased PGC1α expression, mitochondrial DNA copy numbers and integrity, electron transport chain protein CORE II, mitochondrial mass, oxygen consumption rate, and overall ATP production. Further mechanistic studies using mitoquinone (MitoQ), a mitochondria-targeted antioxidant and L-NAME, a nitric oxide synthase (NOS) inhibitor demonstrated that peroxynitrite (at low micromolar levels) induced mitochondrial biogenesis. These findings provide the first evidence that low levels of peroxynitrite can initiate a protective signaling cascade involving mitochondrial biogenesis which may help to restore mitochondrial function following transient MnSOD inactivation.
    01/2014; 2:348-57. DOI:10.1016/j.redox.2014.01.014
  • Jay C Marecki, Nirmala Parajuli, John P Crow, Lee Ann Macmillan-Crow
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    ABSTRACT: Significance: Respiring mitochondria are a significant site for reactions involving reactive oxygen and nitrogen species that contribute to irreversible cellular, structural and functional damage leading to multiple pathological conditions. Manganese superoxide dismutase (MnSOD) is a critical component of the antioxidant system tasked with protecting the oxidant-sensitive mitochondrial compartment from oxidative stress. Since global knockout of MnSOD results in significant cardiac and neuronal damage leading to early postnatal lethality, this approach has limited use for studying the mechanisms of oxidant stress and the development of disease in specific tissues lacking MnSOD. To circumvent this problem, a number of investigators have employed the Cre/loxP system to precisely knock out MnSOD in individual tissues. Recent Advances: Multiple tissue and organ-specific Cre-expressing mice have been generated which greatly enhance the specificity of MnSOD knockout in tissues and organ systems that were once difficult, if not impossible to study. Critical Issues: Evaluating the contribution of MnSOD deficiency to oxidant-mediated mitochondrial damage requires careful consideration of the promoter system used for creating the tissue-specific knockout animal, in addition to the collection and interpretation of multiple indices of oxidative stress and damage. Future Directions: Expanded use of well-characterized tissue-specific promoter elements and inducible systems to drive the Cre/loxP recombinational events will lead to a spectrum of MnSOD tissue knockout models, and a clearer understanding of the role of MnSOD in preventing mitochondrial dysfunction in human disease.
    Antioxidants & Redox Signaling 05/2013; 20(10). DOI:10.1089/ars.2013.5293 · 8.20 Impact Factor
  • Naeem K Patil, Hamida Saba, Lee Ann Macmillan-Crow
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    ABSTRACT: Mitochondria are at the heart of all cellular processes as they provide majority of the energy needed for various metabolic processes. Nitric oxide has been shown to have numerous roles in regulation of mitochondrial function. Mitochondria have enormous pools of glutathione (GSH≈5-10mM). Nitric oxide can react with glutathione to generate a physiological molecule, S-nitrosoglutathione (GSNO). The impact GSNO has on mitochondrial function has been intensively studied in recent years, and several mitochondrial electron transport chain complex proteins have been shown to be targeted by GSNO. In the present study we investigated the effect of GSNO on mitochondrial function using normal rat proximal tubular kidney cells (NRK cells). GSNO treatment of NRK cells lead to mitochondrial membrane depolarization and significant reduction in activities of mitochondrial complex IV and manganese superoxide dismutase enzyme (MnSOD). MnSOD is a critical endogenous antioxidant enzyme which scavenges excess superoxide radicals in the mitochondria. The decrease in MnSOD activity was not associated with a reduction in its protein levels and treatment of NRK cell lysate with dithiothreitol (a strong sulfhydryl group reducing agent) restored MnSOD activity to control values. GSNO is known to cause both S-nitrosylation and S-glutathionylation, which involve the addition of NO and GS- groups respectively, to protein sulfhydryl (-SH) groups of cysteine residues. Endogenous GSH is an essential mediator in S-glutathionylation of cellular proteins, and the current studies revealed that GSH is required for MnSOD inactivation following GSNO or diamide treatment in rat kidney cells as well as in isolated kidneys. Further studies showed that GSNO lead to glutathionylation of MnSOD; however, glutathionylated recombinant MnSOD was not inactivated. This suggests that a more complex pathway, possibly involving the participation of multiple proteins that leads to MnSOD inactivation after GSNO treatment. The major highlight of these studies is the fact that dithiothreitol can restore MnSOD activity following GSNO treatment. To our knowledge, this is the first study showing that MnSOD activity can be reversibly regulated in vivo, through a mechanism involving thiol residues.
    Free Radical Biology and Medicine 12/2012; DOI:10.1016/j.freeradbiomed.2012.12.001 · 5.27 Impact Factor
  • Nirmala Parajuli, Lee Ann Macmillan-Crow
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    ABSTRACT: Excessive generation of superoxide and mitochondrial dysfunction has been described as being important events during ischemia/reperfusion (I/R) injury. Our laboratory has demonstrated that manganese superoxide dismutase (MnSOD), a major mitochondrial antioxidant that eliminates superoxide, is inactivated during renal transplantation and renal I/R, and precedes development of renal failure. We hypothesized that MnSOD knockdown in the kidney augments renal damage during renal I/R. Using newly characterized kidney-specific MnSOD knockout (KO) mice the extent of renal damage and oxidant production after I/R was evaluated. These KO mice (without I/R) exhibited low expression and activity of MnSOD in the distal nephrons, had altered renal morphology, increased oxidant production, but surprisingly showed no alteration in renal function. After I/R the MnSOD KO mice showed similar levels of injury to the distal nephrons when compared to wild type mice. Moreover, renal function, MnSOD activity, and tubular cell death were not significantly altered between the two genotypes after I/R. Interestingly, MnSOD KO alone increased autophagosome formation, mitochondrial biogenesis, and DNA replication/repair within the distal nephrons. These findings suggest that the chronic oxidative stress as a result of MnSOD knockdown induced multiple coordinated cell survival signals including autophagy and mitochondrial biogenesis which protected the kidney against the acute oxidative stress following I/R.
    AJP Renal Physiology 11/2012; 304(3). DOI:10.1152/ajprenal.00435.2012 · 4.42 Impact Factor
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    ABSTRACT: Cold preservation has greatly facilitated the use of cadaveric kidneys for transplantation but damage occurs during the preservation episode. It is well established that oxidant production increases during cold renal preservation and mitochondria are a key target for injury. Our laboratory has demonstrated that cold storage of renal cells and rat kidneys leads to increased mitochondrial superoxide levels and mitochondrial electron transport chain damage, and that addition of Mitoquinone (MitoQ) to the preservation solutions blunted this injury. In order to better translate animal studies, the inclusion of large animal models is necessary to develop safe preclinical protocols. Therefore, we tested the hypothesis that addition of MitoQ to cold storage solution preserves mitochondrial function by decreasing oxidative stress, leading to less renal tubular damage during cold preservation of porcine kidneys employing a standard criteria donor model. Results showed that cold storage significantly induced oxidative stress (nitrotyrosine), renal tubular damage, and cell death. Using High Resolution Respirometry and fresh porcine kidney biopsies to assess mitochondrial function we showed that MitoQ significantly improved complex II/III respiration of the electron transport chain following 24 hours of cold storage. In addition, MitoQ blunted oxidative stress, renal tubular damage, and cell death after 48 hours. These results suggested that MitoQ decreased oxidative stress, tubular damage and cell death by improving mitochondrial function during cold storage. Therefore this compound should be considered as an integral part of organ preservation solution prior to transplantation.
    PLoS ONE 11/2012; 7(11):e48590. DOI:10.1371/journal.pone.0048590 · 3.53 Impact Factor
  • Nirmala Parajuli, Lee Ann MacMillan-Crow
    Free Radical Biology and Medicine 11/2012; 53:S27. DOI:10.1016/j.freeradbiomed.2012.10.067 · 5.71 Impact Factor
  • Naeem K Patil, Nirmala Parajuli, Philip R Mayeux, Lee Ann MacMillan-Crow
    Free Radical Biology and Medicine 11/2012; 53:S114. DOI:10.1016/j.freeradbiomed.2012.10.280 · 5.71 Impact Factor
  • Free Radical Biology and Medicine 11/2012; 53:S110-S111. DOI:10.1016/j.freeradbiomed.2012.10.268 · 5.71 Impact Factor
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    Philip R Mayeux, Lee Ann MacMillan-Crow
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    ABSTRACT: One of the most frequent and serious complications to develop in septic patients is acute kidney injury (AKI), a disorder characterized by a rapid failure of the kidneys to adequately filter the blood, regulate ion and water balance, and generate urine. AKI greatly worsens the already poor prognosis of sepsis and increases cost of care. To date, therapies have been mostly supportive; consequently there has been little change in the mortality rates over the last decade. This is due, at least in part, to the delay in establishing clinical evidence of an infection and the associated presence of the systemic inflammatory response syndrome and thus, a delay in initiating therapy. A second reason is a lack of understanding regarding the mechanisms leading to renal injury, which has hindered the development of more targeted therapies. In this review, we summarize recent studies, which have examined the development of renal injury during sepsis and propose how changes in the peritubular capillary microenvironment lead to and then perpetuate microcirculatory failure and tubular epithelial cell injury. We also discuss a number of potential therapeutic targets in the renal peritubular microenvironment, which may prevent or lessen injury and/or promote recovery.
    Pharmacology [?] Therapeutics 01/2012; 134(2):139-55. DOI:10.1016/j.pharmthera.2012.01.004 · 7.75 Impact Factor
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    Elina Pathak, Lee Ann MacMillan-Crow, Philip R Mayeux
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    ABSTRACT: Oxidative stress has been implicated to play a major role in multiorgan dysfunction during sepsis. To study the mechanism of oxidant generation in acute kidney injury (AKI) during sepsis, we developed an in vitro model of sepsis using primary cultures of mouse cortical tubular epithelial cells exposed to serum (2.5-10%) collected from mice at 4 h after induction of sepsis by cecal ligation and puncture (CLP) or Sham (no sepsis). CLP serum produced a concentration-dependent increase in nitric oxide (NO) (nitrate + nitrite) release at 6 h and cytotoxicity (lactate dehydrogenase release) at 18 h compared with Sham serum treatment. Before cytotoxicity there was a decrease in mitochondrial membrane potential, which was followed by increased superoxide and peroxynitrite levels compared with Sham serum. The role of oxidants was evaluated by using the superoxide dismutase mimetic and peroxynitrite scavenger manganese(III)tetrakis(1-methyl-4-pyridyl)porphyrin tetratosylate hydroxide (MnTmPyP). MnTmPyP (10-100 μM) produced a concentration-dependent preservation of ATP and protection against cytotoxicity. MnTmPyP blocked mitochondrial superoxide and peroxynitrite generation produced by CLP serum but had no effect on NO levels. Although MnTmPyP did not block the initial CLP serum-induced fall in mitochondrial membrane potential, it allowed mitochondrial membrane potential to recover. Data from this in vitro model suggest a time-dependent generation of mitochondrial oxidants, mitochondrial dysfunction, and renal tubular epithelial cell injury and support the therapeutic potential of manganese porphyrin compounds in preventing sepsis-induced AKI.
    Journal of Pharmacology and Experimental Therapeutics 01/2012; 340(1):192-201. DOI:10.1124/jpet.111.183756 · 3.89 Impact Factor
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    ABSTRACT: In overdose acetaminophen (APAP) is hepatotoxic. Toxicity occurs by metabolism to N-acetyl-p-benzoquinone imine, which depletes GSH and covalently binds to proteins followed by protein nitration. Nitration can occur via the strong oxidant and nitrating agent peroxynitrite, formed from superoxide and nitric oxide (NO). In hepatocyte suspensions we reported that an inhibitor of neuronal nitric-oxide synthase (nNOS; NOS1), which has been reported to be in mitochondria, inhibited toxicity and protein nitration. We recently showed that manganese superoxide dismutase (MnSOD; SOD2) was nitrated and inactivated in APAP-treated mice. To understand the role of nNOS in APAP toxicity and MnSOD nitration, nNOS knockout (KO) and wild-type (WT) mice were administered APAP (300 mg/kg). In WT mice serum alanine aminotransferase (ALT) significantly increased at 6 and 8 h, and serum aspartate aminotransferase (AST) significantly increased at 4, 6 and 8 h; however, in KO mice neither ALT nor AST significantly increased until 8 h. There were no significant differences in hepatic GSH depletion, APAP protein binding, hydroxynonenal covalent binding, or histopathological assessment of toxicity. The activity of hepatic MnSOD was significantly lower at 1 to 2 h in WT mice and subsequently increased at 8 h. MnSOD activity was not altered at 0 to 6 h in KO mice but was significantly decreased at 8 h. There were significant increases in MnSOD nitration at 1 to 8 h in WT mice and 6 to 8 h in KO mice. Significantly more nitration occurred at 1 to 6 h in WT than in KO mice. MnSOD was the only observed nitrated protein after APAP treatment. These data indicate a role for nNOS with inactivation of MnSOD and ALT release during APAP toxicity.
    Journal of Pharmacology and Experimental Therapeutics 01/2012; 340(1):134-42. DOI:10.1124/jpet.111.184192 · 3.89 Impact Factor
  • Akira Marine, Nirmala Parajuli, Lee Ann MacMillan-Crow
    Free Radical Biology and Medicine 11/2011; 51. DOI:10.1016/j.freeradbiomed.2011.10.415 · 5.71 Impact Factor
  • Naeem K Patil, Nirmala Parajuli, Philip R. Mayeux, Lee Ann MacMillan-Crow
    Free Radical Biology and Medicine 11/2011; 51. DOI:10.1016/j.freeradbiomed.2011.10.120 · 5.71 Impact Factor
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    ABSTRACT: Inactivation of manganese superoxide dismutase (MnSOD), a mitochondrial antioxidant, has been associated with renal disorders and often results in detrimental downstream events that are mechanistically not clear. Development of an animal model that exhibits kidney-specific deficiency of MnSOD would be extremely beneficial in exploring the downstream events that occur following MnSOD inactivation. Using Cre-Lox recombination technology, kidney-specific MnSOD deficient mice (both 100% and 50%) were generated that exhibited low expression of MnSOD in discrete renal cell types and reduced enzymatic activity within the kidney. These kidney-specific 100% KO mice possessed a normal life-span, although it was interesting that the mice were smaller. Consistent with the important role in scavenging superoxide radicals, the kidney-specific KO mice showed a significant increase in oxidative stress (tyrosine nitration) in a gene-dose dependent manner. In addition, loss of MnSOD resulted in mild renal damage (tubular dilation and cell swelling). Hence, this novel mouse model will aid in determining the specific role (local and/or systemic) governed by MnSOD within certain kidney cells. Moreover, these mice will serve as a powerful tool to explore molecular mechanisms that occur downstream of MnSOD inactivation in renal disorders or possibly in other pathologies that rely on normal renal function.
    Free Radical Biology and Medicine 07/2011; 51(2):406-16. DOI:10.1016/j.freeradbiomed.2011.04.024 · 5.27 Impact Factor
  • Lee Ann Macmillan-Crow, John P Crow
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    ABSTRACT: Superoxide dismutases (SODs) are a family of important antioxidant enzymes that catalyze the conversion of superoxide to hydrogen peroxide and oxygen. Hydrogen peroxide is then detoxified by a host of antioxidant enzymes. A common misconception is that the increased MnSOD levels will result in increased hydrogen peroxide levels. Herein we offer some potential reasons for this confusion, as well as some potential resolutions. Data are offered that demonstrate the ability of MnSOD, in the presence of nitric oxide, to utilize hydrogen peroxide to produce superoxide and the more toxic oxidant, peroxynitrite.
    Anti-cancer agents in medicinal chemistry 03/2011; DOI:10.2174/187152011795255939
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    ABSTRACT: The majority of kidneys used for transplantation are obtained from deceased donors. These kidneys must undergo cold preservation/storage before transplantation to preserve tissue quality and allow time for recipient selection and transport. However, cold storage (CS) can result in tissue injury, kidney discardment, or long-term renal dysfunction after transplantation. We have previously determined mitochondrial superoxide and other downstream oxidants to be important signaling molecules that contribute to CS plus rewarming (RW) injury of rat renal proximal tubular cells. Thus, this study's purpose was to determine whether adding mitoquinone (MitoQ), a mitochondria-targeted antioxidant, to University of Wisconsin (UW) preservation solution could offer protection against CS injury. CS was initiated by placing renal cells or isolated rat kidneys in UW solution alone (4 h at 4°C) or UW solution containing MitoQ or its control compound, decyltriphenylphosphonium bromide (DecylTPP) (1 μM in vitro; 100 μM ex vivo). Oxidant production, mitochondrial function, cell viability, and alterations in renal morphology were assessed after CS exposure. CS induced a 2- to 3-fold increase in mitochondrial superoxide generation and tyrosine nitration, partial inactivation of mitochondrial complexes, and a significant increase in cell death and/or renal damage. MitoQ treatment decreased oxidant production ~2-fold, completely prevented mitochondrial dysfunction, and significantly improved cell viability and/or renal morphology, whereas DecylTPP treatment did not offer any protection. These findings implicate that MitoQ could potentially be of therapeutic use for reducing organ preservation damage and kidney discardment and/or possibly improving renal function after transplantation.
    Journal of Pharmacology and Experimental Therapeutics 03/2011; 336(3):682-92. DOI:10.1124/jpet.110.176743 · 3.89 Impact Factor
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    ABSTRACT: In overdose the analgesic/antipyretic acetaminophen (APAP) is hepatotoxic. Toxicity is mediated by initial hepatic metabolism to N-acetyl-p-benzoquinone imine (NAPQI). After low doses NAPQI is efficiently detoxified by GSH. However, in overdose GSH is depleted, NAPQI covalently binds to proteins as APAP adducts, and oxygen/nitrogen stress occurs. Toxicity is believed to occur by mitochondrial dysfunction. Manganese superoxide dismutase (MnSOD) inactivation by protein nitration has been reported to occur during other oxidant stress-mediated diseases. MnSOD is a critical mitochondrial antioxidant enzyme that prevents peroxynitrite formation within the mitochondria. To examine the role of MnSOD in APAP toxicity, mice were treated with 300 mg/kg APAP. GSH was significantly reduced by 65% at 0.5 h and remained reduced from 1 to 4 h. Serum alanine aminotransferase did not significantly increase until 4 h and was 2290 IU/liter at 6 h. MnSOD activity was significantly reduced by 50% at 1 and 2 h. At 1 h, GSH was significantly depleted by 62 and 80% at nontoxic doses of 50 and 100 mg/kg, respectively. No further GSH depletion occurred with hepatotoxic doses of 200 and 300 mg/kg APAP. A dose response decrease in MnSOD activity was observed for APAP at 100, 200, and 300 mg/kg. Immunoprecipitation of MnSOD from livers of APAP-treated mice followed by Western blot analysis revealed nitrated MnSOD. APAP-MnSOD adducts were not detected. Treatment of recombinant MnSOD with NAPQI did not produce APAP protein adducts. The data indicate that MnSOD inactivation by nitration is an early event in APAP-induced hepatic toxicity.
    Journal of Pharmacology and Experimental Therapeutics 12/2010; 337(1):110-6. DOI:10.1124/jpet.110.176321 · 3.89 Impact Factor
  • Angela S Burke, Lee Ann Macmillan-Crow, Jack A Hinson
    Chemical Research in Toxicology 11/2010; 23(12). DOI:10.1021/tx1003744 · 4.19 Impact Factor

Publication Stats

3k Citations
211.12 Total Impact Points


  • 2005–2014
    • University of Arkansas at Little Rock
      Little Rock, Arkansas, United States
  • 2007–2012
    • University of Arkansas for Medical Sciences
      • Department of Pharmacology and Toxicology
      Little Rock, Arkansas, United States
  • 1994–2003
    • University of Alabama at Birmingham
      • • Department of Surgery
      • • Division of Molecular and Cellular Pathology
      Birmingham, Alabama, United States