Iron deposition in gastric black spots: Clinicopathological insights and NanoSuit-correlative light and electron microscopy analysis.

Objectives: Black spots (BSs) are lentiginous findings observed in the gastric body and fundus during upper gastrointestinal endoscopy and are predominantly seen in patients undergoing Helicobacter pylori eradication treatment. However, the detailed patient background and exact composition are poorly understood. This study aims to clarify the clinicopathological features of BSs, examine patient demographics, and use the NanoSuit-correlative light and electron microscopy (CLEM) method combined with scanning electron microscopy-energy dispersive X-ray spectroscopy for elemental analysis. Methods: Patients who underwent upper gastrointestinal endoscopy between 2017 and 2022 were included. Data on age, medications, blood tests, and H. pylori infection status were retrospectively gathered from medical records. Univariate analysis was conducted to examine BS presence, with results then used in a multivariate model to identify associated risk factors. Additionally, pathological specimens from patients with BSs were analyzed for elemental composition using the NanoSuit-CLEM method combined with scanning electronmicroscopy-energy dispersive X-ray spectroscopy. Results: An analysis of 6778 cases identified risk factors for BSs, including older age and using proton pump inhibitors, statins, corticosteroids, and antithrombotic drugs. Endoscopically, BSs correlated with higher gastric atrophy and lower active H. pylori infection. Iron deposition at BS sites was specifically identified using NanoSuit-CLEM. Conclusions: BSs on gastrointestinal endoscopy may indicate an absence of active H. pylori inflammation. The discovery of iron deposition within BSs using the NanoSuit-CLEM method has offered new insights into the possible causative factors and advances our understanding of the etiology of BSs, bringing us closer to unraveling the underlying mechanisms of their formation.

Rare presentations of small bowel endometriosis.

Despite endometriosis being a relatively common chronic gynecological condition in women of childbearing age, small bowel endometriosis is rare. Presentations can vary from completely asymptomatic to reported symptoms of abdominal pain, bloating, and diarrhea. The following two cases depict very atypical manifestations of ileal endometriosis that presented as obscure intermittent gastrointestinal bleeding and bowel obstruction requiring surgical intervention. The first case describes a previously healthy 40-year-old woman with severe symptomatic iron deficiency anemia and intermittent melena. A small bowel enteroscopy diagnosed multiple ulcerated strictures in the distal small bowel as the likely culprit. Despite nonsteroidal anti-inflammatory drug-induced enteropathy being initially considered as the likely etiology, histopathological examination of the resected distal ileal segment revealed evidence of endometriosis. The second case describes a 66-year-old with a presumptive diagnosis of Crohn's disease who reported a 10-year history of intermittent perimenstrual abdominal pain, diarrhea, and nausea with vomiting. Following two subsequent episodes of acute bowel obstruction and surgical resection of the patient's stricturing terminal ileal disease, histopathological examination demonstrated active chronic inflammation with endometriosis. Small bowel endometriosis should be considered as an unusual differential diagnosis in women who may present with obscure gastrointestinal bleeding from the small bowel or recurrent bowel obstruction.

Structures and Electron Transport Paths in the Four Families of Flavin-Based Electron Bifurcation Enzymes.

Oxidoreductases facilitating electron transfer between molecules are pivotal in metabolic pathways. Flavin-based electron bifurcation (FBEB), a recently discovered energy coupling mechanism in oxidoreductases, enables the reversible division of electron pairs into two acceptors, bridging exergonic and otherwise unfeasible endergonic reactions. This chapter explores the four distinct FBEB complex families and highlights a decade of structural insights into FBEB complexes. In this chapter, we discuss the architecture, electron transfer routes, and conformational changes across all FBEB families, revealing the structural foundation that facilitate these remarkable functions.

Anaemia at mid-pregnancy is associated with prehypertension in late pregnancy among urban women.

Background: Antenatal iron deficiency and anaemia are associated with gestational hypertension and diabetes mellitus, but so are elevated iron stores and haemoglobin. In South Africa, pregnant women receive routine iron supplementation regardless of iron status. Aim: This study aimed to assess associations of antenatal iron status and anaemia with blood pressure in pregnant women in urban South Africa. Secondary to this, associations with heart rate, fasting glucose and glucose tolerance were also investigated. Setting: Johannesburg, South Africa. Methods: A total of 250 pregnant women, aged 27 (24-32) years, were recruited using consecutive sampling. The authors measured biomarkers of iron status and anaemia at < 18 and ± 22 weeks', blood pressure and heart rate at ± 36 weeks', and fasting glucose and glucose tolerance between 24 and 28 weeks' gestation. Associations were determined using multivariable regression models adjusted for confounders. Results: The odds of prehypertension in late pregnancy among women with anaemia at ± 22 weeks' gestation were three times higher than among women without anaemia (odds ratio [OR]: 3.01, 95% confidence interval [CI]: 1.22, 7.42). Participants with anaemia at ± 22 weeks' gestation had 2.15 times higher odds of having elevated mean arterial pressure than women without anaemia (OR: 2.15, 95% CI: 1.01, 4.60). Conclusion: Anaemia at mid-pregnancy could be a predictor of hypertensive disorders in pregnancy. The cause of antenatal anaemia may need further investigation apart from iron deficiency. The effective management of anaemia in pregnant women living in urban South Africa remains a challenge. Contribution: This study provides evidence about the health impact of pregnant women regarding antenatal supplementation practices in South Africa.

Ribonuclease inhibitor 1 emerges as a potential biomarker and modulates inflammation and iron homeostasis in sepsis.

Sepsis, marked by organ dysfunction, necessitates reliable biomarkers. Ribonuclease inhibitor 1 (RNH1), a ribonuclease (RNase) inhibitor, emerged as a potential biomarker for acute kidney injury and mortality in thoracoabdominal aortic aneurysm patients. Our study investigates RNH1 dynamics in sepsis, its links to mortality and organ dysfunction, and the interplay with RNase 1 and RNase 5. Furthermore, we explore RNH1 as a therapeutic target in sepsis-related processes like inflammation, non-canonical inflammasome activation, and iron homeostasis. We showed that RNH1 levels are significantly higher in deceased patients compared to sepsis survivors and correlate with creatine kinase, aspartate and alanine transaminase, bilirubin, serum creatinine and RNase 5, but not RNase 1. RNH1 mitigated LPS-induced TNFα and RNase 5 secretion, and relative mRNA expression of ferroptosis-associated genes HMOX1, FTH1 and HAMP in PBMCs. Monocytes were identified as the predominant type of LPS-positive PBMCs. Exogenous RNH1 attenuated LPS-induced CASP5 expression, while increasing IL-1ß secretion in PBMCs and THP-1 macrophages. As RNH1 has contradictory effects on inflammation and non-canonical inflammasome activation, its use as a therapeutic agent is limited. However, RNH1 levels may play a central role in iron homeostasis during sepsis, supporting our clinical observations. Hence, RNH1 shows promise as biomarkers for renal and hepatic dysfunction and hepatocyte injury, and may be useful in predicting the outcome of septic patients.

Optimizing water relations, gas exchange parameters, biochemical attributes and yield of water-stressed maize plants through seed priming with iron oxide nanoparticles.

Drought poses significant risks to maize cultivation by impairing plant growth, water uptake and yield; nano priming offers a promising avenue to mitigate these effects by enhancing plant water relations, stress tolerance and overall productivity. In the current experiment, we tested a hypothesis that seed priming with iron oxide nanoparticles (n-Fe2O3) can improve maize performance under water stress by improving its growth, water relations, yield and biochemical attributes. The experiment was conducted on a one main plot bisected into two subplots corresponding to the water and drought environments. Within each subplot, maize plants were raised from n-Fe2O3 primed seeds corresponding to 0 mg. L- 1 (as control treatment), 25, 50, 75, and 100 mg. L- 1 (as trial treatments). Seed priming with n-Fe2O3 at a concentration of 75 mg. L- 1 improved the leaf relative water content, water potential, photosynthetic water use efficiency, and leaf intrinsic water use efficiency of maize plants by 13%, 44%, 64% and 17%, respectively compared to control under drought stress. The same treatments improved plant biochemical attributes such as total chlorophyll content, total flavonoids and ascorbic acid by 37%, 22%, and 36%, respectively. Seed priming with n-Fe2O3 accelerated the functioning of antioxidant enzymes such as SOD and POD and depressed the levels of leaf malondialdehyde and hydrogen peroxide significantly. Seed priming with n-Fe2O3 at a concentration of 75 mg. L- 1 improved cob length, number of kernel rows per cob, and 100 kernel weight by 59%, 27% and 33%, respectively, under drought stress. Seed priming with n-Fe2O3 can be used to increase maize production under limited water scenarios.

Feasibility and performance of spin-echo EPI MR elastography at 3 Tesla for staging hepatic fibrosis in the presence of hepatic iron overload.

PURPOSE: To assess the feasibility and performance of MR elastography (MRE) for quantifying liver fibrosis in patients with and without hepatic iron overload. METHODS: This retrospective single-center study analyzed 139 patients who underwent liver MRI at 3 Tesla including MRE (2D spin-echo EPI sequence) and R2* mapping for liver iron content (LIC) estimation. MRE feasibility and diagnostic performance between patients with normal and elevated LIC were compared. RESULTS: Patients with elevated LIC (21%) had significantly higher MRE failure rates (24.1% vs. 3.6%, p < 0.001) compared to patients with normal LIC (79%). For those with only insignificant to mild iron overload (LIC < 5.4 mg/g; 17%), MRE failure rate did not differ significantly from patients without iron overload (8.3% vs. 3.6%, p = 0.315). R2* predicted MRE failure with fair accuracy at a threshold of R2* ≥ 269 s-1 (LIC of approximately 4.6 mg/g). MRE showed good diagnostic performance for detecting significant (≥ F2) and severe fibrosis (≥ F3) in patients without (AUC 0.835 and 0.900) and with iron overload (AUC 0.818 and 0.889) without significant difference between the cohorts (p = 0.884 and p = 0.913). For detecting cirrhosis MRE showed an excellent diagnostic performance in both groups (AUC 0.944 and 1.000, p = 0.009). CONCLUSION: Spin-echo EPI MRE at 3 Tesla is feasible in patients with mild iron overload with good to excellent performance for detecting hepatic fibrosis with a failure rate comparable to patients without iron overload.

Anticancer therapeutic potential of multimodal targeting agent- "phosphorylated galactosylated chitosan coated magnetic nanoparticles" against N-nitrosodiethylamine-induced hepatocellular carcinoma.

Superparamagnetic iron oxide nanoparticles (SPIONs) are extensively used as carriers in targeted drug delivery and has several advantages in the field of magnetic hyperthermia, chemodynamic therapy and magnet assisted radionuclide therapy. The characteristics of SPIONs can be tailored to deliver drugs into tumor via "passive targeting" and they can also be coated with tissue-specific agents to enhance tumor uptake via "active targeting". In our earlier studies, we developed HCC specific targeting agent- "phosphorylated galactosylated chitosan"(PGC) for targeting asialoglycoprotein receptors. Considering their encouraging results, in this study we developed a multifunctional targeting system- "phosphorylated galactosylated chitosan-coated magnetic nanoparticles"(PGCMNPs) for targeting HCC. PGCMNPs were synthesized by co-precipitation method and characterized by DLS, XRD, TEM, VSM, elemental analysis and FT-IR spectroscopy. PGCMNPs were evaluated for in vitro antioxidant properties, uptake in HepG2 cells, biodistribution, in vivo toxicity and were also evaluated for anticancer therapeutic potential against NDEA-induced HCC in mice model in terms of tumor status, electrical properties, antioxidant defense status and apoptosis. The characterization studies confirmed successful formation of PGCMNPs with superparamagnetic properties. The internalization studies demonstrated (99-100)% uptake of PGCMNPs in HepG2 cells. These results were also supported by biodistribution studies in which increased iron content (296%) was noted inside the hepatocytes. Further, PGCMNPs exhibited no in vivo toxicity. The anticancer therapeutic potential was evident from observation that PGCMNPs treatment decreased tumor bearing animals (41.6%) and significantly (p ≤ 0.05) lowered tumor multiplicity. Overall, this study indicated that PGCMNPs with improved properties are efficiently taken-up by hepatoma cells and has therapeutic potential against HCC. Further, this agent can be tagged with 32P and hence can offer multimodal cancer treatment options via radiation ablation as well as magnetic hyperthermia.

Development and validation of a faecal immunochemical test-based model in the work-up of patients with iron deficiency anaemia.

Objective: In patients with iron deficiency anaemia (IDA), the diagnostic yield of gastroscopy and colonoscopy (bidirectional endoscopy) in detecting neoplastic lesions is low. This study aimed to develop and validate a faecal immunochemical test (FIT)-based model to optimise the work-up of patients with IDA. Methods: Outpatients with IDA were enrolled in a prospective, multicentre study from April 2016 to October 2019. One FIT was performed before bidirectional endoscopy. Significant gastrointestinal lesions were recorded and a combined model developed with variables that were independently associated with significant colorectal lesions in the multivariate analysis. The model cut-off was selected to provide a sensitivity of at least 95% for colorectal cancer (CRC) detection, and its performance was compared to different FIT cut-offs. The data set was randomly split into two groups (developed and validation cohorts). An online calculator was developed for clinical application. Results: The development and validation cohorts included 373 and 160 patients, respectively. The developed model included FIT value, age, and sex. In the development and validation cohorts, a model cut-off of 0.1375 provided a negative predictive value of 98.1 and 96.7% for CRC and 90.7 and 88.3% for significant colorectal lesions, respectively. This combined model reduced the rate of missed significant colorectal lesions compared to FIT alone and could have avoided more than one-fourth of colonoscopies. Conclusion: The FIT-based combined model developed in this study may serve as a useful diagnostic tool to triage IDA patients for early endoscopic referral, resulting in considerable reduction of unnecessary colonoscopies.

NDRG1 acts as an oncogene in triple-negative breast cancer and its loss sensitizes cells to mitochondrial iron chelation.

Multiple studies indicate that iron chelators enhance their anti-cancer properties by inducing NDRG1, a known tumor and metastasis suppressor. However, the exact role of NDRG1 remains controversial, as newer studies have shown that NDRG1 can also act as an oncogene. Our group recently introduced mitochondrially targeted iron chelators deferoxamine (mitoDFO) and deferasirox (mitoDFX) as effective anti-cancer agents. In this study, we evaluated the ability of these modified chelators to induce NDRG1 and the role of NDRG1 in breast cancer. We demonstrated that both compounds specifically increase NDRG1 without inducing other NDRG family members. We have documented that the effect of mitochondrially targeted chelators is at least partially mediated by GSK3α/ß, leading to phosphorylation of NDRG1 at Thr346 and to a lesser extent on Ser330. Loss of NDRG1 increases cell death induced by mitoDFX. Notably, MDA-MB-231 cells lacking NDRG1 exhibit reduced extracellular acidification rate and grow slower than parental cells, while the opposite is true for ER+ MCF7 cells. Moreover, overexpression of full-length NDRG1 and the N-terminally truncated isoform (59112) significantly reduced sensitivity towards mitoDFX in ER+ cells. Furthermore, cells overexpressing full-length NDRG1 exhibited a significantly accelerated tumor formation, while its N-terminally truncated isoforms showed significantly impaired capacity to form tumors. Thus, overexpression of full-length NDRG1 promotes tumor growth in highly aggressive triple-negative breast cancer.

Do new lakes behave like natural lakes regarding sediment composition and phosphorus fluxes?

Numerous new lakes have been established during the last few decades. Lakes established on former agricultural soils often have high legacy phosphorus (P)-content, which constitutes a risk for potential internal P-loading after the lake is formed. In this study, we compared the P release and sediment P-pools from 31 new lakes and 31 natural lakes, to assess their similarities and differences. A suite of other sediment characteristics was identified and compared for both natural and new lakes; catchment characteristics of the new lakes also were analyzed. P release from the sediment of new lakes was significantly lower than from natural lakes (13.2 mg P m-2 d-1) compared to new lakes (6.9 mg P m-2 d-1). The P release was found to be low when molar Fe:P ratios were above 10. A significant correlation was found between the content of mobile-P (loosely adsorbed P, iron-bound P, and leachable organic P) and TP in the sediment, irrespective of lake type. The composition of the mobile P-pool also differed, with the new non-excavated lakes showing a higher proportion of RP-BD; both new lake types had significantly (p = 0.021) lower proportions of nrP, compared to natural lakes in the uppermost 10 cm sediment. In addition, variance in P release and mobile-P content of new lakes could be explained in terms of the land use of the catchments. Most sediment characteristics of new lakes established without topsoil excavation reached the average levels of natural Danish lakes with respect to density, organic content and P content within 20-30 years, while excavated lakes showed no such tendencies.

What are the different biomolecules involved in the selective recovery of REEs from mining wastewater using FeNPs synthesized from two plant extracts?

Extracting rare earth elements (REEs) from wastewater is crucial for saving the environment, sustainable use of natural resources and economic growth. Reported here is a simple, low cost and one-step synthesis of Fe nanoparticles (FeNPs) based on two plant extracts having the ability to recover REEs. The synthesis of FeNPs using Excoecaria cochinchinensis leaves extract (Ec-FeNPs) exhibited high selectivity for heavy rare earth due to unique biomolecules, achieving separation coefficients (Kd) of 3.16 × 103-4.04 × 106 mL/g and recovery efficiencies ranging from 71.7 to 100 %. Conversely, the synthesis of FeNPs using Pinus massoniana lamb extract (PML-FeNPs) revealed poorer REE recovery efficiencies of 7.2-86.7 %. To understand the differences between Ec-FeNPs and PML-FeNPs in terms of selectivity and efficiency, LC-QTOF-MS served to analyze the biomolecules differences of two plant extracts. In addition, various types of characterization were carried out to identify the different functional groups encapsulated on the surface of FeNPs. These results reveal the source of the difference in the selectivity of Ec-FeNPs and PML-FeNPs for REEs. Furthermore, during DFT calculations, it was found that biomolecules with varying affinities for the surface of FeNPs interact with each other, leading to the formation of structures that exhibit high reactivity towards REEs. Finally, incorporating Spearman correlation analysis demonstrates that the selective removal efficiency of REEs was closely linked to surface complexation, ion exchange, and electrostatic adsorption. Consequently, this work strongly highlights the potential for the practical application of novel adsorbents in this field.

Faecal immunochemical tests can improve colonoscopy triage in patients with iron deficiency: A systematic review and meta-analysis.

BACKGROUND: Use of the faecal immunochemical test (FIT) to triage patients with iron deficiency (ID) for colonoscopy due to suspected colorectal cancer (CRC) may improve distribution of colonoscopic resources. We reviewed the diagnostic performance of FIT for detecting advanced colorectal neoplasia, including CRC and advanced pre-cancerous neoplasia (APCN), in patients with ID, with or without anaemia. METHODS: We performed a systematic review of three databases for studies comprising of patients with ID, with or without anaemia, completing a quantitative FIT within six months prior to colonoscopy, where test performance was compared against the reference standard colonoscopy. Random effects meta-analyses determined the diagnostic performance of FIT for advanced colorectal neoplasia. RESULTS: Nine studies were included on a total of n=1761 patients with ID, reporting FIT positivity thresholds between 4-150 µg haemoglobin/g faeces. Only one study included a non-anaemic ID (NAID) cohort. FIT detected CRC and APCN in ID patients with 90.7 % and 49.3 % sensitivity, and 81.0 % and 82.4 % specificity, respectively. FIT was 88.0 % sensitive and 83.4 % specific for CRC in patients with ID anaemia at a FIT positivity threshold of 10 µg haemoglobin/g faeces. CONCLUSIONS: FIT shows high sensitivity for advanced colorectal neoplasia and may be used to triage those with ID anaemia where colonoscopic resources are limited, enabling those at higher risk of CRC to be prioritised for colonoscopy. There is a need for further research investigating the diagnostic performance of FIT in NAID patients.

A clinical study evaluating low dose ferrous fumarate vs. standard iron supplements in iron-deficient non-anemic to mild anemic adults.

Our study aims to validate safety and efficacy of Feroglobin capsule compared with different iron supplementations in adult subjects diagnosed with non-anemic to mild anemic iron deficiency and fatigue. Enrolled 302 participants diagnosed with non-anemic to mild anemic iron deficiency and fatigue. Group A (n = 147) received Feroglobin, Group B (n = 146) received standard of care [Haem Up Gems capsules (Ferrous fumarate) or Fericip tablets (Ferrous ascorbate)]. 293 subjects completed the study with follow-up visits on days 30, 60, and 90. Feroglobin treatment significantly increased hemoglobin levels from mean 12.43 g/dl to 13.24 g/dl in 90 days. Ferritin levels improved significantly by 442.87% compared to the standard care's 256.67%. Fatigue scale scores reduced by 47.51%, and all presenting health complaints resolved completely. Gastrointestinal symptoms observed were similar in both the groups. Both groups exhibited moderate treatment adherence. Quality of life improved in pain and general health domains, exhibiting a good tolerability. Adverse events were unrelated to the investigational products. Feroglobin serves as an efficacious therapeutic alternative for improving hemoglobin, ferritin, and reducing fatigue with low doses compared to standard of care. However, longer-term effects of low-dose require further investigations in different target groups.

The relationship between liver stiffness by two-dimensional shear wave elastography and iron overload status in transfusion-dependent patients.

Increased liver stiffness (LS) can be result of increased liver iron concentration (LIC) which may not yet be reflected in the liver fibrotic status. The objective of our study was to examine relationship between hemochromatosis, LS, and serum ferritin level in transfusion-dependent patients. We recruited all 70 transfusion-dependent patients, whose median age was 15, referred for evaluating LIC status by magnetic resonance imaging (MRI) followed by two-dimensional ultrasonography shear wave elastography (2D-SWE). Thalassemia beta affected the majority of the patients. The optimal cut point for prediction of severe hemochromatosis using median SWE (kPa) and SWV (m/s) was ≥ 7.0 kPa and ≥ 1.54 m/s, respectively, with sensitivity of 0.76 (95% confidence interval [CI] 0.55, 0.91) and, specificity of 0.69 (95%CI 0.53, 0.82). When combing the optimal cut point of SWE (kPa) at ≥ 7.0 and serum ferritin ≥ 4123 ng/mL, the sensitivity increased to 0.84 (95%CI 0.64, 0.95) with specificity of 0.67 (95%CI 0.50, 0.80), positive predictive value (PPV) of 0.60 (95%CI 0.42, 0.76), and negative predictive value (NPV) of 0.88 (95%CI 0.71, 0.96). Simultaneous tests of 2D-SWE and serum ferritin for prediction of severe hemochromatosis showed the highest sensitivity of 84% (95%CI 0.64-0.95), as compared to 2D-SWE alone at 76% (95%CI 0.55, 0.91) or serum ferritin alone at 44% (95%CI 0.24-0.65). We recommend measuring both 2D-SWE and serum ferritin in short interval follow up patients. Adding 2D-SWE to management guideline will help in deciding for aggressive adjustment of iron chelating medication and increased awareness of patients having severe hemochromatosis.

Construction of Hierarchically Biomimetic Iron Oxide Nanosystems for Macrophage Repolarization-Promoted Immune Checkpoint Blockade of Cancer Immunotherapy.

Cancer immunotherapy is developing as the mainstream strategy for treatment of cancer. However, the interaction between the programmed cell death protein-1 (PD-1) and the programmed death ligand 1 (PD-L1) restricts T cell proliferation, resulting in the immune escape of tumor cells. Recently, immune checkpoint inhibitor therapy has achieved clinical success in tumor treatment through blocking the PD-1/PD-L1 checkpoint pathway. However, the presence of M2 tumor-associated macrophages (TAMs) in the tumor microenvironment (TME) will inhibit antitumor immune responses and facilitate tumor growth, which can weaken the effectiveness of immune checkpoint inhibitor therapy. The repolarization of M2 TAMs into M1 TAMs can induce the immune response to secrete proinflammatory factors and active T cells to attack tumor cells. Herein, hollow iron oxide (Fe3O4) nanoparticles (NPs) were prepared for reprogramming M2 TAMs into M1 TAMs. BMS-202, a small-molecule PD-1/PD-L1 inhibitor that has a lower price, higher stability, lower immunogenicity, and higher tumor penetration ability compared with antibodies, was loaded together with pH-sensitive NaHCO3 inside hollow Fe3O4 NPs, followed by wrapping with macrophage membranes. The formed biomimetic FBN@M could produce gaseous carbon dioxide (CO2) from NaHCO3 in response to the acidic TME, breaking up the macrophage membranes to release BMS-202. A series of in vitro and in vivo assessments revealed that FBN@M could reprogram M2 TAMs into M1 TAMs and block the PD-1/PD-L1 pathway, which eventually induced T cell activation and the secretion of TNF-α and IFN-γ to kill the tumor cells. FBN@M has shown a significant immunotherapeutic efficacy for tumor treatment.

Iron-catalyzed C-7 selective NH2 amination of indoles.

7-Aminoindoles are important synthetic intermediates to a broad range of bioactive molecules. Transition metal-catalyzed directed C-H amination is among the most straightforward route for their synthesis, whereas methods that could directly incorporate an NH2 group in a highly selective manner remains elusive. Moreover, there is still high demand for the development of earth-abundant metal catalysis for such attractive reactivity. We present here the first C-7 selective NH2 amination of indoles through a directed homolytic aromatic substitution (HAS) with iron-aminyl radical. The reaction exhibits broad substrate scope, tolerates variety of functional groups, and is readily scalable with catalyst loading down to 0.1 mol% and turnover number (TON) up to 4500.

Anemia From Inflammation After Intracerebral Hemorrhage and Relationships With Outcome.

BACKGROUND: Baseline anemia is associated with poor intracerebral hemorrhage (ICH) outcomes. However, underlying drivers for anemia and whether anemia development after ICH impacts clinical outcomes are unknown. We hypothesized that inflammation drives anemia development after ICH and assessed their relationship to outcomes. METHODS AND RESULTS: Patients with serial hemoglobin and iron biomarker concentrations from the HIDEF (High-Dose Deferoxamine in Intracerebral Hemorrhage) trial were analyzed. Adjusted linear mixed models assessed laboratory changes over time. Of 42 patients, significant decrements in hemoglobin occurred with anemia increasing from 19% to 45% by day 5. Anemia of inflammation iron biomarker criteria was met in 88%. A separate cohort of 521 patients with ICH with more granular serial hemoglobin and long-term neurological outcome data was also investigated. Separate regression models assessed whether (1) systemic inflammatory response syndrome (SIRS) scores related to hemoglobin changes over time and (2) hemoglobin changes related to poor 90-day outcome. In this cohort, anemia prevalence increased from 30% to 71% within 2 days of admission yet persisted beyond this time. Elevated systemic inflammatory response syndrome was associated with greater hemoglobin decrements over time (adjusted parameter estimate: -0.27 [95% CI, -0.37 to -0.17]) and greater hemoglobin decrements were associated with poor outcomes (adjusted odds ratio per 1 g/dL increase, 0.76 [95% CI, 0.62-0.93]) independent to inflammation and ICH severity. CONCLUSIONS: We identified novel findings that acute anemia development after ICH is common, rapid, and related to inflammation. Because anemia development is associated with poor outcomes, further work is required to clarify if anemia, or its underlying drivers, are modifiable treatment targets that can improve ICH outcomes. REGISTRATION: https://www.clinicaltrials.gov Unique identifier: NCT01662895.

Binding of IscU and TusA to different but competing sites of IscS influences the activity of IscS and directs sulfur to the respective biomolecular synthesis pathway.

All sulfur transfer pathways generally have in common an l-cysteine desulfurase as the initial sulfur-mobilizing enzyme, which serves as a sulfur donor for the biosynthesis of numerous sulfur-containing biomolecules in the cell. In Escherichia coli, the housekeeping l-cysteine desulfurase IscS functions as a hub for sulfur transfer through interactions with several partner proteins, which bind at different sites on IscS. So far, the interaction sites of IscU, Fdx, CyaY, and IscX involved in iron sulfur (Fe-S) cluster assembly, TusA, required for molybdenum cofactor biosynthesis and mnm5s2U34 transfer RNA (tRNA) modifications, and ThiI, involved in both the biosynthesis of thiamine and s4U8 tRNA modifications, have been mapped. Previous studies have suggested that IscS partner proteins bind only one at a time, with the exception of Fe-S cluster assembly, which involves the formation of a ternary complex involving IscS, IscU, and one of CyaY, Fdx, or IscX. Here, we show that the affinity of TusA for IscS is similar to but lower than that of IscU and that these proteins compete for binding to IscS. We show that heterocomplexes involving the IscS dimer and single IscU and TusA molecules are readily formed and that binding of both TusA and IscU to IscS affects its l-cysteine desulfurase activity. A model is proposed in which the delivery of sulfur to different sulfur-requiring pathways is controlled by sulfur acceptor protein levels, IscS-binding affinities, and acceptor protein-modulated IscS desulfurase activity.IMPORTANCEIron-sulfur clusters are evolutionarily ancient prosthetic groups. The housekeeping l-cysteine desulfurase IscS functions as a central core for sulfur transfer through interactions with several partner proteins, which bind at different sites on each IscS monomer with different affinities and partially overlapping binding sites. We show that heterocomplexes involving the IscS dimer and single IscU and TusA molecules at each site of the dimer are formed, thereby influencing the activity of IscS.

Strain variation in the Candida albicans iron limitation response.

Iron acquisition is critical for pathogens to proliferate during invasive infection, and the human fungal pathogen Candida albicans is no exception. The iron regulatory network, established in reference strain SC5314 and derivatives, includes the central player Sef1, a transcription factor that activates iron acquisition genes in response to iron limitation. Here, we explored potential variation in this network among five diverse C. albicans strains through mutant analysis, Nanostring gene expression profiling, and, for two strains, RNA-Seq. Our findings highlight four features that may inform future studies of natural variation and iron acquisition in this species. (i) Conformity: In all strains, major iron acquisition genes are upregulated during iron limitation, and a sef1Δ/Δ mutation impairs that response and growth during iron limitation. (ii) Response variation: Some aspects of the iron limitation response vary among strains, notably the activation of hypha-associated genes. As this gene set is tied to tissue damage and virulence, variation may impact the progression of infection. (iii) Genotype-phenotype variation: The impact of a sef1Δ/Δ mutation on cell wall integrity varies, and for the two strains examined the phenotype correlated with sef1Δ/Δ impact on several cell wall integrity genes. (iv) Phenotype discovery: DNA repair genes were induced modestly by iron limitation in sef1Δ/Δ mutants, with fold changes we would usually ignore. However, the response occurred in both strains tested and was reminiscent of a much stronger response described in Cryptococcus neoformans, a suggestion that it may have biological meaning. In fact, we observed that the iron limitation of a sef1Δ/Δ mutant caused recessive phenotypes to emerge at two heterozygous loci. Overall, our results show that a network that is critical for pathogen proliferation presents variation outside of its core functions.IMPORTANCEA key virulence factor of Candida albicans is the ability to maintain iron homeostasis in the host where iron is scarce. We focused on a central iron regulator, SEF1. We found that iron regulator Sef1 is required for growth, cell wall integrity, and genome integrity during iron limitation. The novel aspect of this work is the characterization of strain variation in a circuit that is required for survival in the host and the connection of iron acquisition to genome integrity in C. albicans.