The p21+ perinecrotic hepatocytes produce the chemokine CXCL14 after a severe acetaminophen overdose promoting hepatocyte injury and delaying regeneration.

Fifty percent of all acute liver failure (ALF) cases in the United States are due to acetaminophen (APAP) overdose. Assessment of canonical features of liver injury, such as plasma alanine aminotransferase activities are poor predictors of acute liver failure (ALF), suggesting the involvement of additional mechanisms independent of hepatocyte death. Previous work demonstrated a severe overdose of APAP results in impaired regeneration, the induction of senescence by p21, and increased mortality. We hypothesized that a discrete population of p21+ hepatocytes acquired a secretory phenotype that directly impedes liver recovery after a severe APAP overdose. Leveraging in-house human APAP explant liver and publicly available single-nuclei RNAseq data, we identified a subpopulation of p21+ hepatocytes enriched in a unique secretome of factors, such as CXCL14. Spatial transcriptomics in the mouse model of APAP overdose confirmed the presence of a p21+ hepatocyte population that directly surrounded the necrotic areas. In both male and female mice, we found a dose-dependent induction of p21 and persistent circulating levels of the p21-specific constituent, CXCL14, in the plasma after a severe APAP overdose. In parallel experiments, we targeted either the putative senescent hepatocytes with the senolytic drugs, dasatinib and quercetin, or CXCL14 with a neutralizing antibody. We found that targeting CXCL14 greatly enhanced liver recovery after APAP-induced liver injury, while targeting senescent hepatocytes had no effect. These data support the conclusion that the sustained induction of p21 in hepatocytes with persistent CXCL14 secretion are critical mechanistic events leading to ALF in mice and human patients.

The chemokine CXCL14 is a novel early prognostic biomarker for poor outcome in acetaminophen-induced acute liver failure.

BACKGROUND AND AIMS: Patients with acetaminophen-induced acute liver failure are more likely to die while on the liver transplant waiting list than those with other causes of acute liver failure. Therefore, there is an urgent need for prognostic biomarkers that can predict the need for liver transplantation early after an acetaminophen overdose. APPROACH AND RESULTS: We evaluated the prognostic potential of plasma chemokine C-X-C motif ligand 14 (CXCL14) concentrations in patients with acetaminophen (APAP) overdose (n=50) and found that CXCL14 is significantly higher in nonsurviving patients compared to survivors with acute liver failure ( p < 0.001). Logistic regression and AUROC analyses revealed that CXCL14 outperformed the MELD score, better discriminating between nonsurvivors and survivors. We validated these data in a separate cohort of samples obtained from the Acute Liver Failure Study Group (n = 80), where MELD and CXCL14 had similar AUC (0.778), but CXCL14 demonstrated higher specificity (81.2 vs. 52.6) and positive predictive value (82.4 vs. 65.4) for death or need for liver transplantation. Next, combining the patient cohorts and using a machine learning training/testing scheme to mimic the clinical scenario, we found that CXCL14 outperformed MELD based on AUC (0.821 vs. 0.787); however, combining MELD and CXCL14 yielded the best AUC (0.860). CONCLUSIONS: We find in 2 independent cohorts of acetaminophen overdose patients that circulating CXCL14 concentration is a novel early prognostic biomarker for poor outcomes, which may aid in guiding decisions regarding patient management. Moreover, our findings reveal that CXCL14 performs best when measured soon after patient presentation to the clinic, highlighting its importance for early warning of poor prognosis.

CT imaging features of bile duct stent complications.

Biliary stents have been widely used to treat both malignant and benign biliary obstruction. Biliary stenting serves as a temporary measure to maintain ductal patency and promote bile drainage. Biliary decompression can help relieve clinical symptoms of pain, obstructive jaundice, pruritis, fat malabsorption, and failure to thrive and prevent disease progression, such as secondary biliary cirrhosis and end-stage liver failure. Endoscopic placement of biliary endoprosthesis is a minimally invasive procedure well tolerated by most patients but is not without problems. Multiple early and late complications have been reported in the literature and Computed Tomography (CT) is the most used modality to assess normal positions and evaluate patients suspected of stent complications. The aim of this article is to provide a review various of biliary stent related complications, as seen on CT. Current literature on risk factors, diagnosis and management is also discussed.

A Polygenic Risk Score for Predicting Racial and Genetic Susceptibility to Prurigo Nodularis.

Prurigo nodularis (PN) is an understudied inflammatory skin disease characterized by pruritic, hyperkeratotic nodules. Identifying the genetic factors underlying PN could help to better understand its etiology and guide the development of therapies. In this study, we developed a polygenic risk score that predicts a diagnosis of PN (OR = 1.41, P = 1.6 × 10-5) in two independent and continentally distinct populations. We also performed GWASs, which uncovered genetic variants associated with PN, including one near PLCB4 (rs6039266: OR = 3.15, P = 4.8 × 10-8) and others near TXNRD1 (rs34217906: OR = 1.71, P = 6.4 × 10-7; rs7134193: OR = 1.57, P = 1.1 × 10-6). Finally, we discovered that Black patients have over a two-times greater genetic risk of developing PN (OR = 2.63, P = 7.8 × 10-4). Combining the polygenic risk score and self-reported race together was significantly predictive of PN (OR = 1.32, P = 4.7 × 10-3). Strikingly, this association was more significant with race than after adjusting for genetic ancestry. Because race is a sociocultural construct and not a genetically bound category, our findings suggest that genetics, environmental influence, and social determinants of health likely affect the development of PN and may contribute to clinically observed racial disparities.

Dose-dependent pleiotropic role of neutrophils during acetaminophen-induced liver injury in male and female mice.

Acetaminophen (APAP) overdose is the leading cause of acute liver failure in western countries. APAP can cause extensive hepatocellular necrosis, which triggers an inflammatory response involving neutrophil and monocyte recruitment. Particularly the role of neutrophils in the injury mechanism of APAP hepatotoxicity has been highly controversial. Thus, the objective of the current study was to assess whether a potential contribution of neutrophils was dependent on the APAP dose and the sex of the animals. Male and female C57BL/6 J mice were treated with 300 or 600 mg/kg APAP and the injury and inflammatory cell recruitment was evaluated between 6 and 48 h. In both male and female mice, ALT plasma levels and the areas of necrosis peaked at 12-24 h after both doses with more severe injury at the higher dose. In addition, Ly6g-positive neutrophils started to accumulate in the liver at 6 h and peaked at 6-12 h after 300 mg/kg and 12-24 h after 600 mg/kg for both sexes; however, the absolute numbers of hepatic neutrophils in the liver were significantly higher after the 600 mg/kg dose. Neutrophil infiltration correlated with mRNA levels of the neutrophil chemoattractant Cxcl2 in the liver. Treating mice with an anti-Cxcl2 antibody at 2 h after APAP significantly reduced neutrophil accumulation at 24 h after both doses and in both sexes. However, the injury was significantly reduced only after the high overdose. Thus, neutrophils, recruited through Cxcl2, have no effect on APAP-induced liver injury after 300 mg/kg but aggravate the injury only after severe overdoses.

Early clinical and economic outcomes of expanded criteria living kidney donors in the United States.

BACKGROUND: The donation of what might be termed expanded criteria kidneys has become an increasingly common practice. This study aimed to assign expanded criteria and non-expanded criteria donation status and examine early clinical and economic outcomes among expanded criteria and non-expanded criteria living kidney donor (LKD) hospitalizations in the US. METHODS: Healthcare cost and Utilization Project-National (Nationwide) Inpatient Sample (HCUP-NIS) data (Jan 2008-Dec 2019, N = 12,020) were used. Expanded criteria LKDs were identified as admitted patients aged ≥ 60 years, or 50-59 years with any comorbidity that historically precluded donation. The Clavien-Dindo system was applied to classify surgical complications as grade I-IV/V. RESULTS: The number of LKD admissions decreased by 31% over the study period, although this trend fluctuated over time. Compared to non-expanded criteria LKD admissions, expanded criteria LKD admissions had comparable surgical complication rates in Grade I (aOR 1.0, 0.8-1.3), but significantly higher surgical complication rates in Grade II (aOR 1.5, 1.1-2.2) and Grade III (aOR 1.4, 1.0-2.0). The two groups had comparable hospital length of stay and cost in the adjusted models. Notably, Grade II complications were significantly higher in private, for-profit hospitals (15%) compared to government hospitals (2.9%). CONCLUSIONS: Expanded criteria LKDs had comparable early outcomes compared to non-expanded criteria LKDs, but the trends evident in LKDs over time and the variation in complication records warrant further research.

Human Wharton's Jelly-derived mesenchymal stem cells prevent acetaminophen-induced liver injury in a mouse model unlike human dermal fibroblasts.

The persistence of hepatotoxicity induced by N-acetyl-para-aminophenol (Acetaminophen or Paracetamol, abbreviated as APAP) as the most common cause of acute liver failure in the United States, despite the availability of N-acetylcysteine, illustrates the clinical relevance of additional therapeutic approaches. While human mesenchymal stem cells (MSCs) have shown protection in mouse models of liver injury, the MSCs used are generally not cleared for human use and it is unclear whether these effects are due to xenotransplantation. Here we evaluated GMP manufactured clinical grade human Wharton's Jelly mesenchymal stem cells (WJMSCs), which are currently being investigated in human clinical trials, in a mouse model of APAP hepatotoxicity in comparison to human dermal fibroblasts (HDFs) to address these issues. C57BL6J mice were treated with a moderate APAP overdose (300 mg/kg) and WJMSCs were administered 90 min later. Liver injury was evaluated at 6 and 24 h after APAP. WJMSCs treatment reduced APAP-induced liver injury at both time points unlike HDFs, which showed no protection. APAP-induced JNK activation as well as AIF and Smac release from mitochondria were prevented by WJMSCs treatment without influencing APAP bioactivation. Mechanistically, WJMSCs treatment upregulated expression of Gclc and Gclm to enhance recovery of liver GSH levels to attenuate mitochondrial dysfunction and accelerated recovery of pericentral hepatocytes to re-establish liver zonation and promote liver homeostasis. Notably, preventing GSH resynthesis with buthionine sulfoximine prevented the protective effects of WJMSCs. These data indicate that these GMP-manufactured WJMCs could be a clinically relevant therapeutic approach in the management of APAP hepatotoxicity in humans.

Generation of pro-and anti-inflammatory mediators after acetaminophen overdose in surviving and non-surviving patients.

Acetaminophen (APAP) overdose causes liver injury in animals and humans. Although well-studied in animals, limited longitudinal data exist on cytokine release after APAP overdose in patients. The purpose of this study was to quantify concentrations of cytokines in APAP overdose patients to determine if early cytokine or complement measurements can distinguish between surviving and non-surviving patients. Plasma was obtained from healthy controls, APAP overdose patients with no increase in liver transaminases, and surviving and non-surviving APAP overdose patients with severe liver injury. Interleukin-10 (IL-10), and CC chemokine ligand-2 (CCL2, MCP-1) were substantially elevated in surviving and non-surviving patients, whereas IL-6 and CXC chemokine ligand-8 (CXCL8, IL-8) had early elevations in a subset of patients only with liver injury. Day 1 IL-10 and IL-6 levels, and Day 2 CCL2, levels correlated positively with survival. There was no significant increase in IL-1α, IL-1ß or TNF-α in any patient during the first week after APAP. Monitoring cytokines such as CCL2 may be a good indicator of patient prognosis; furthermore, these data indicate the inflammatory response after APAP overdose in patients is not mediated by a second phase of inflammation driven by the inflammasome.

Platanosides, a Potential Botanical Drug Combination, Decrease Liver Injury Caused by Acetaminophen Overdose in Mice.

Oxidative stress plays an important role in acetaminophen (APAP)-induced hepatotoxicity. Platanosides (PTSs) isolated from the American sycamore tree (Platanus occidentalis) represent a potential new four-molecule botanical drug class of antibiotics active against drug-resistant infectious disease. Preliminary studies have suggested that PTSs are safe and well tolerated and have antioxidant properties. The potential utility of PTSs in decreasing APAP hepatotoxicity in mice in addition to an assessment of their potential with APAP for the control of infectious diseases along with pain and pyrexia associated with a bacterial infection was investigated. On PTS treatment in mice, serum alanine aminotransferase (ALT) release, hepatic centrilobular necrosis, and 4-hydroxynonenal (4-HNE) were markedly decreased. In addition, inducible nitric oxide synthase (iNOS) expression and c-Jun-N-terminal kinase (JNK) activation decreased when mice overdosed with APAP were treated with PTSs. Computational studies suggested that PTSs may act as JNK-1/2 and Keap1-Nrf2 inhibitors and that the isomeric mixture could provide greater efficacy than the individual molecules. Overall, PTSs represent promising botanical drugs for hepatoprotection and drug-resistant bacterial infections and are effective in protecting against APAP-related hepatotoxicity, which decreases liver necrosis and inflammation, iNOS expression, and oxidative and nitrative stresses, possibly by preventing persistent JNK activation.

Recovered Hepatocytes Promote Macrophage Apoptosis Through CXCR4 After Acetaminophen-Induced Liver Injury in Mice.

Acetaminophen (APAP) overdose is the main cause of acute liver failure in Western countries. The mechanism of APAP hepatotoxicity is associated with centrilobular necrosis which initiates infiltration of neutrophils, monocytes, and other leukocytes to the area of necrosis. Although it has been recognized that this infiltration of immune cells plays a critical role in promoting liver repair, mechanism of immune cell clearance that is important for resolution of inflammation and the return to normal homeostasis are not well characterized. CXCR4 is a chemokine receptor expressed on hepatocytes as well as neutrophils, monocytes, and hematopoietic stem cells. CXCR4 function is dependent on its selective expression on different cell types and thus can vary depending on the pathophysiology. This study aimed to investigate the crosstalk between hepatocytes and macrophages through CXCR4 to promote macrophage apoptosis after APAP overdose. C57BL/6J mice were subjected to APAP overdose (300 mg/kg). Flow cytometry and immunohistochemistry were used to determine the mode of cell death of macrophages and expression pattern of CXCR4 during the resolution phase of APAP hepatotoxicity. The impact of CXCR4 in regulation of macrophage apoptosis and liver recovery was assessed after administration of a monoclonal antibody against CXCR4. RNA sequencing analysis was performed on flow cytometry sorted CXCR4+ macrophages at 72 h to confirm the apoptotic cell death of macrophages. Our data indicate that the inflammatory response is resolved by recovering hepatocytes through induction of CXCR4 on macrophages, which triggers their cell death by apoptosis at the end of the recovery phase.

Hospital Costs and Fatality Rates of Traumatic Assaults by Mechanism in the US, 2016-2018.

Importance: Estimates of the total economic cost of firearm violence are important in drawing attention to this public health issue; however, studies that consider violence more broadly are needed to further the understanding of the extent to which such costs can be avoided. Objectives: To estimate the association of firearm assaults with US hospital costs and deaths compared with other assault types. Design, Setting, and Participants: The 2016-2018 US Nationwide Emergency Department Sample and National Inpatient Sample, Healthcare Cost and Utilization Project were used in this cross-sectional study of emergency department (ED) and inpatient admissions for assaults involving a firearm, sharp object, blunt object, or bodily force identified using International Statistical Classification of Diseases, Tenth Revision, Clinical Modification codes. Differences in ED and inpatient costs (2020 US dollars) across mechanisms were estimated using ordinary least-squares regression with and without adjustments for year and hospital, patient, and injury characteristics. The Centers for Disease Control and Prevention underlying cause of death data were used to estimate national death rates and hospital case-fatality rates across mechanisms. Cost analysis used a weighted sample. National death rates and hospital case-fatality rates used US resident death certificates, covering 976 million person-years. Hospital case-fatality rates also used nationally weighted ED records covering 2.7 million admissions. Data analysis was conducted from March 1, 2021, to March 31, 2022. Exposure: The primary exposure was the mechanism used in the assault. Main Outcomes and Measures: Emergency department and inpatient costs per record. National death rates and hospital case-fatality rates. Results: Overall, 2.4 million ED visits and 184 040 inpatient admissions for assault were included. Across all mechanisms, the mean age of the population was 32.7 (95% CI, 32.6-32.9) years in the ED and 36.4 (95% CI, 36.2-36.7) years in the inpatient setting; 41.9% (95% CI, 41.2%-42.5%) were female in the ED, and 19.1% (95% CI, 18.6%-19.6%) of inpatients were female. Most assaults recorded in the ED involved publicly insured or uninsured patients and hospitals in the Southern US. Emergency department costs were $678 (95% CI, $657-$699) for bodily force, $861 (95% CI, $813-$910) for blunt object, $996 (95% CI, $925-$1067) for sharp object, and $1388 (95% CI, $1254-$1522) for firearm assaults. Corresponding inpatient costs were $14 702 (95% CI, $14 178-$15 227) for bodily force, $17 906 (95% CI, $16 888-$18 923) for blunt object, $19 265 (95% CI, $18 475-$20 055) for sharp object, and $34 949 (95% CI, $33 654-$36 244) for firearm assaults. National death rates per 100 000 were 0.04 (95% CI, 0.03-0.04) for bodily force, 0.03 (95% CI, 0.03-0.03) for blunt object, 0.54 (95% CI, 0.52-0.55) for sharp object, and 4.40 (95% CI, 4.36-4.44) for firearm assaults. Hospital case fatality rates were 0.01% (95% CI, 0.009%-0.012%) for bodily force, 0.05% (95% CI, 0.04%-0.06%) for blunt object, 1.05% (95% CI, 1.00%-1.09%) for sharp object, and 15.26% (95% CI, 15.04%-15.49%) for firearm assaults. In regression analysis, ED costs for firearm assaults were 59% to 99% higher than costs for nonfirearm assaults, and inpatient costs were 67% to 118% higher. Conclusions and Relevance: The findings of this study suggest that it may be useful for policies aimed at reducing the costs of firearm violence to consider violence more broadly to understand the extent to which costs can be avoided.

Iron Availability within the Leaf Vasculature Determines the Magnitude of Iron Deficiency Responses in Source and Sink Tissues in Arabidopsis.

Iron (Fe) uptake and translocation in plants are fine-tuned by complex mechanisms that are not yet fully understood. In Arabidopsis thaliana, local regulation of Fe homeostasis at the root level has been extensively studied and is better understood than the systemic shoot-to-root regulation. While the root system is solely a sink tissue that depends on photosynthates translocated from source tissues, the shoot system is a more complex tissue, where sink and source tissues occur synchronously. In this study, and to gain better insight into the Fe deficiency responses in leaves, we overexpressed Zinc/Iron-regulated transporter-like Protein (ZIP5), an Fe/Zn transporter, in phloem-loading cells (proSUC2::AtZIP5) and determined the timing of Fe deficiency responses in sink (young leaves and roots) and source tissues (leaves). Transgenic lines overexpressing ZIP5 in companion cells displayed increased sensitivity to Fe deficiency in root growth assays. Moreover, young leaves and roots (sink tissues) displayed either delayed or dampened transcriptional responses to Fe deficiency compared to wild-type (WT) plants. We also took advantage of the Arabidopsis mutant nas4x-1 to explore Fe transcriptional responses in the opposite scenario, where Fe is retained in the vasculature but in an unavailable and precipitated form. In contrast to proSUC2::AtZIP5 plants, nas4x-1 young leaves and roots displayed a robust and constitutive Fe deficiency response, while mature leaves showed a delayed and dampened Fe deficiency response compared to WT plants. Altogether, our data provide evidence suggesting that Fe sensing within leaves can also occur locally in a leaf-specific manner.

Robotic pyelolithotomy in a solitary pelvic kidney complicated with fulminant Clostridium difficile: a case report.

BACKGROUND: Robotic-assisted surgeries have gradually become the standard of care for many procedures, especially in the field of urology. Despite the widespread use of robotic assistance in surgeries, data on its postoperative complications are extremely limited. We detail a rare presentation of fulminant Clostridium difficile colitis requiring surgical intervention in a patient with a solitary ectopic pelvic kidney who underwent a robotic-assisted pyelolithotomy. Highlights of the most recent management recommendations for C. difficile infection are also presented. CASE PRESENTATION: A 26-year-old Caucasian woman who underwent a robot-assisted pyelolithotomy of a pelvic kidney developed tachycardia, leukocytosis, and severe diarrhea 2 days following surgery. Because of her long history of antibiotic use, her severe symptoms were concerning for C. difficile colitis. This was confirmed by a C. difficile toxin test and a computed tomography scan. She was given recommended antibiotics, but her condition progressively deteriorated. The patient developed fulminant colitis and toxic megacolon, for which she underwent an exploratory laparotomy with subtotal abdominal colectomy and ileostomy creation on the twelfth day of her hospitalization. She fully recovered and was discharged 3 weeks after her subtotal colectomy. CONCLUSION: Although robotic surgeries have been shown to have several advantages, risk of postsurgical complications remains. We present a rare case of fulminant C. difficile colitis that complicated a robotic-assisted pyelolithotomy. Active prevention, early detection, and optimization of management are essential to preventing unfavorable outcomes.

Lossy compression of statistical data using quantum annealer.

We present a new lossy compression algorithm for statistical floating-point data through a representation learning with binary variables. The algorithm finds a set of basis vectors and their binary coefficients that precisely reconstruct the original data. The optimization for the basis vectors is performed classically, while binary coefficients are retrieved through both simulated and quantum annealing for comparison. A bias correction procedure is also presented to estimate and eliminate the error and bias introduced from the inexact reconstruction of the lossy compression for statistical data analyses. The compression algorithm is demonstrated on two different datasets of lattice quantum chromodynamics simulations. The results obtained using simulated annealing show 3-3.5 times better compression performance than the algorithm based on neural-network autoencoder. Calculations using quantum annealing also show promising results, but performance is limited by the integrated control error of the quantum processing unit, which yields large uncertainties in the biases and coupling parameters. Hardware comparison is further studied between the previous generation D-Wave 2000Q and the current D-Wave Advantage system. Our study shows that the Advantage system is more likely to obtain low-energy solutions for the problems than the 2000Q.

Topological Voting Method for Image Segmentation.

Image segmentation is one of the main problems in image processing. In order to improve the accuracy of segmentation, one often creates a number of masks (annotations) for a same image and then uses some voting methods on these masks to obtain a more accurate mask. In this paper, we propose a voting method whose voting rule is not pixel-wise but takes into account the natural geometric-topological properties of the masks. On three concrete examples, we show that our voting method outperforms the usual arithmetical voting method.

Kupffer cells regulate liver recovery through induction of chemokine receptor CXCR2 on hepatocytes after acetaminophen overdose in mice.

Acetaminophen (APAP) is a widely used analgesic, but also a main cause of acute liver injury in the United States and many western countries. APAP hepatotoxicity is associated with a sterile inflammatory response as shown by the infiltration of neutrophils and monocytes. While the contribution of the immune cells to promote liver repair have been demonstrated, the direct interactions between macrophages or neutrophils with hepatocytes to help facilitate hepatocyte proliferation and tissue repair remain unclear. The purpose of this study was to investigate the relationship between resident macrophages (Kupffer cells) and hepatocytes with a focus on the chemokine receptor CXCR2. C57BL/6J mice were subjected to an APAP overdose (300 mg/kg) and the role of CXCR2 on hepatocytes was investigated using a selective antagonist, SB225002. In addition, clodronate liposomes were used to deplete Kupffer cells to assess changes in CXCR2 expression. Our data showed that CXCR2 was mainly expressed on hepatocytes and it was induced specifically in hepatocytes around the necrotic area 24 h after APAP treatment. Targeting this receptor using an inhibitor caused a delayed liver recovery. Depletion of Kupffer cells significantly prevented CXCR2 induction on hepatocytes. In vitro and in vivo experiments also demonstrated that Kupffer cells regulate CXCR2 expression and pro-regenerative gene expression in surviving hepatocytes through production of IL-10. Thus, Kupffer cells support the transition of hepatocytes around the area of necrosis to a proliferative state through CXCR2 expression.

Root-to-shoot iron partitioning in Arabidopsis requires IRON-REGULATED TRANSPORTER1 (IRT1) protein but not its iron(II) transport function.

IRON-REGULATED TRANSPORTER1 (IRT1) is the root high-affinity ferrous iron (Fe) uptake system and indispensable for the completion of the life cycle of Arabidopsis thaliana without vigorous Fe supplementation. Here we provide evidence supporting a second role of IRT1 in root-to-shoot partitioning of Fe. We show that irt1 mutants overaccumulate Fe in roots, most prominently in the cortex of the differentiation zone in irt1-2, compared to the wild type. Shoots of irt1-2 are severely Fe-deficient according to Fe content and marker transcripts, as expected. We generated irt1-2 lines producing IRT1 mutant variants carrying single amino-acid substitutions of key residues in transmembrane helices IV and V, Ser206 and His232, which are required for transport activity in yeast. Root short-term 55 Fe uptake rates were uninformative concerning IRT1-mediated transport. Overall irt1-like concentrations of the secondary substrate Mn suggested that the transgenic Arabidopsis lines also remain incapable of IRT1-mediated root Fe uptake. Yet, IRT1S206A partially complements rosette dwarfing and leaf chlorosis of irt1-2, as well as root-to-shoot Fe partitioning and gene expression defects of irt1-2, all of which are fully complemented by wild-type IRT1. Taken together, these results suggest a regulatory function for IRT1 in root-to-shoot Fe partitioning that does not require Fe transport activity of IRT1. Among the genes of which transcript levels are partially dependent on IRT1, we identify MYB DOMAIN PROTEIN10, MYB DOMAIN PROTEIN72 and NICOTIANAMINE SYNTHASE4 as candidates for effecting IRT1-dependent Fe mobilization in roots. Understanding the biological functions of IRT1 will help to improve Fe nutrition and the nutritional quality of agricultural crops.

Sarcoidosis Presenting in Breast Imaging Clinic With Unilateral Axillary Lymphadenopathy.

Sarcoidosis is an idiopathic systemic granulomatous disease that presents with noncaseating granulomas most commonly affecting the lungs and mediastinal lymph nodes. Patients often have nonspecific symptoms, including cough of unknown cause, fever, shortness of breath, fatigue, or weight loss. The diagnosis for sarcoidosis is relatively challenging in the sole presence of swollen lymph nodes and the absence of the aforementioned symptoms. We present a case of unilateral axillary lymphadenopathy found on routine mammography; ultimately proven to be an atypical symptom of sarcoidosis. Our goal is to highlight radiologic features that help distinguish sarcoidosis from potential malignancy.

Mitochondrial Membrane Potential Drives Early Change in Mitochondrial Morphology After Acetaminophen Exposure.

Mitochondrial morphology plays a critical role in regulating mitochondrial and cellular function. It is well established that oxidative stress and mitochondrial injury are central to acetaminophen (APAP) hepatotoxicity. However, the role of mitochondrial dynamics, namely the remodeling of mitochondrial morphology through fusion and fission, has largely gone unexplored. To investigate this, we used primary mouse hepatocytes treated with APAP which allowed for real-time visualization of mitochondrial morphology using mitotracker green. We found that alterations in mitochondrial morphology were dose dependent, with a biphasic response in mitochondrial shape at higher APAP doses. Importantly, these two distinct mitochondrial morphologies corresponded with differences in mitochondrial respiratory function and polarization. The early change in mitochondrial morphology can be reversible and appears to be an adaptive response caused by alterations in membrane potential, which ultimately help preserve mitochondrial function. The later delayed change in mitochondrial morphology is irreversible and is driven by loss of mitochondrial membrane potential, decreased canonical fusion proteins, and alterations in mitochondrial lipid composition. Collectively, these later changes tilt the scales toward mitochondrial fission resulting in fragmented mitochondria with reduced functionality. This work provides evidence of adaptive early changes in mitochondrial morphology, which results in functional consequences that are dictated by the severity of APAP overdose.

Impaired protein adduct removal following repeat administration of subtoxic doses of acetaminophen enhances liver injury in fed mice.

Acetaminophen (APAP) is a widely used analgesic and is safe at therapeutic doses. However, an overdose of APAP is hepatotoxic and accidental overdoses are increasingly common due to the presence of APAP in several combination medications. Formation of protein adducts (APAP-CYS) is central to APAP-induced liver injury and their removal by autophagy is an essential adaptive response after an acute overdose. Since the typical treatment for conditions such as chronic pain involves multiple doses of APAP over time, this study investigated APAP-induced liver injury after multiple subtoxic doses and examined the role of autophagy in responding to this regimen. Fed male C57BL/6J mice were administered repeated doses (75 mg/kg and 150 mg/kg) of APAP, followed by measurement of adducts within the liver, mitochondria, and in plasma, activation of the MAP kinase JNK, and markers of liver injury. The role of autophagy was investigated by treatment of mice with the autophagy inhibitor, leupeptin. Our data show that multiple treatments at the 150 mg/kg dose of APAP resulted in protein adduct formation in the liver and mitochondria, activation of JNK, and hepatocyte cell death, which was significantly exacerbated by inhibition of autophagy. While repeated dosing with the milder 75 mg/kg dose did not cause mitochondrial protein adduct formation, JNK activation, or liver injury, autophagy inhibition resulted in hepatocyte death even at this lower dose. These data illustrate the importance of adaptive responses such as autophagy in removing protein adducts and preventing liver injury, especially in clinically relevant situations involving repeated dosing with APAP.