Mechanism of high-mannose N-glycan breakdown and metabolism by Bifidobacterium longum.

Bifidobacteria are early colonizers of the human gut and play central roles in human health and metabolism. To thrive in this competitive niche, these bacteria evolved the capacity to use complex carbohydrates, including mammalian N-glycans. Herein, we elucidated pivotal biochemical steps involved in high-mannose N-glycan utilization by Bifidobacterium longum. After N-glycan release by an endo-ß-N-acetylglucosaminidase, the mannosyl arms are trimmed by the cooperative action of three functionally distinct glycoside hydrolase 38 (GH38) α-mannosidases and a specific GH125 α-1,6-mannosidase. High-resolution cryo-electron microscopy structures revealed that bifidobacterial GH38 α-mannosidases form homotetramers, with the N-terminal jelly roll domain contributing to substrate selectivity. Additionally, an α-glucosidase enables the processing of monoglucosylated N-glycans. Notably, the main degradation product, mannose, is isomerized into fructose before phosphorylation, an unconventional metabolic route connecting it to the bifid shunt pathway. These findings shed light on key molecular mechanisms used by bifidobacteria to use high-mannose N-glycans, a perennial carbon and energy source in the intestinal lumen.

Structure optimization of lipopeptide assemblies for aldol reactions in an aqueous medium.

Four amphiphilic peptides were synthesized, characterized, and evaluated regarding their efficiency in the catalysis of direct aldol reactions in water. The lipopeptides differ by having a double lipid chain and a guanidinium pyrrole group functionalizing one Lys side chain. All the samples are composed of the amino acids l-proline (P), l-arginine (R), or l-lysine (K) functionalized with the cationic guanidiniocarbonyl pyrrole unit (GCP), l-tryptophan (W), and l-glycine (G), covalently linked to one or two long aliphatic chains, leading to surfactant-like designs with controlled proline protonation state and different stereoselectivity. Critical aggregation concentrations (cac) were higher in the presence of the GCP group, suggesting that self-assembly depends on charge distribution along the peptide backbone. Cryogenic Transmission Electron Microscopy (Cryo-TEM) and Small Angle X-ray Scattering (SAXS) showed a rich polymorphism including spherical, cylindrical, and bilayer structures. Molecular dynamics simulations performed to assess the lipopeptide polymorphs revealed an excellent agreement with core-shell arrangements derived from SAXS data and provided an atomistic view of the changes incurred by modifying head groups and lipid chains. The resulting nanostructures behaved as excellent catalysts for aldol condensation reactions, in which superior conversions (>99%), high diastereoselectivities (ds = 94 : 6), and enantioselectivities (ee = 92%) were obtained. Our findings contribute to elucidate the effect of nanoscale organization of lipopeptide assemblies in the catalysis of aldol reactions in an aqueous environment.

Nanoparticles containing ß-cyclodextrin potentially useful for the treatment of Niemann-Pick C.

ß-Cyclodextrin (ß-CD) is being considered a promising therapy for Niemann-Pick C (NPC) disease because of its ability to mobilise the entrapped cholesterol from lysosomes, however, a major limitation is its inability to cross the blood-brain barrier (BBB) and address the central nervous system (CNS) manifestations of the disease. Considering this, we aimed to design nanoparticles able to cross the BBB and deliver ß-CD into the CNS lysosomes. The physicochemical characteristics of ß-CD-loaded nanoparticles were evaluated by dynamic light scattering, small-angle X-ray scattering, and cryogenic transmission electron microscopy. The in vitro analyses were performed with NPC dermal fibroblasts and the ß-CD-loaded nanoparticles were tracked in vivo. The nanoparticles showed a mean diameter around 120 nm with a disordered bicontinuous inner structure. The nanoparticles did not cause decrease in cell viability, impairment in the antioxidant enzymes activity, damage to biomolecules or release of reactive species in NPC dermal fibroblasts; also, they did not induce genotoxicity or alter the mitochondrial function in healthy fibroblasts. The ß-CD-loaded nanoparticles were taken up by lysosomes reducing the cholesterol accumulated in NPC fibroblasts and reached the CNS of mice more intensely than other organs, demonstrating advantages compared to the free ß-CD. The results demonstrated the potential of the ß-CD-loaded nanoparticles in reducing the brain impairment of NPC.

The origin and evolution of human glutaminases and their atypical C-terminal ankyrin repeats.

On the basis of tissue-specific enzyme activity and inhibition by catalytic products, Hans Krebs first demonstrated the existence of multiple glutaminases in mammals. Currently, two human genes are known to encode at least four glutaminase isoforms. However, the phylogeny of these medically relevant enzymes remains unclear, prompting us to investigate their origin and evolution. Using prokaryotic and eukaryotic glutaminase sequences, we built a phylogenetic tree whose topology suggested that the multidomain architecture was inherited from bacterial ancestors, probably simultaneously with the hosting of the proto-mitochondrion endosymbiont. We propose an evolutionary model wherein the appearance of the most active enzyme isoform, glutaminase C (GAC), which is expressed in many cancers, was a late retrotransposition event that occurred in fishes from the Chondrichthyes class. The ankyrin (ANK) repeats in the glutaminases were acquired early in their evolution. To obtain information on ANK folding, we solved two high-resolution structures of the ANK repeat-containing C termini of both kidney-type glutaminase (KGA) and GLS2 isoforms (glutaminase B and liver-type glutaminase). We found that the glutaminase ANK repeats form unique intramolecular contacts through two highly conserved motifs; curiously, this arrangement occludes a region usually involved in ANK-mediated protein-protein interactions. We also solved the crystal structure of full-length KGA and present a small-angle X-ray scattering model for full-length GLS2. These structures explain these proteins' compromised ability to assemble into catalytically active supra-tetrameric filaments, as previously shown for GAC. Collectively, these results provide information about glutaminases that may aid in the design of isoform-specific glutaminase inhibitors.

A sumatriptan coarse-grained model to explore different environments: interplay with experimental techniques.

In this work, we developed a coarse-grained model of sumatriptan suitable for extensive molecular dynamics simulations. First, we confirmed the interfacial distribution of this drug in bilayers through cryogenic transmission electron microscopy and small-angle X-ray scattering techniques, as was predicted by our previous atomistic simulations. Based on these simulations, we developed a coarse-grained model for sumatriptan able to reproduce its overall molecular behavior, captured by atomistic simulations and experiments. We then tested the sumatriptan model in a micellar environment along with experimental characterization of sumatriptan-loaded micelles. The simulation results showed good agreement with photon correlation spectroscopy and electrophoretic mobility experiments performed in this work. The particle size of the obtained micelles was comparable with the simulated ones; meanwhile, zeta-potential results suggest adsorption of the drug on the micellar surface. This model is a step forward in the search for a suitable drug-delivery system for sumatriptan.

Risk factors for invasive fusariosis in patients with acute myeloid leukemia and in hematopoietic cell transplant recipients.

BACKGROUND: Risk factors for invasive fusariosis (IF) have not been characterized. We attempted to identify risk factors for IF in a prospective cohort of hematologic patients treated in 8 centers in Brazil. METHODS: Patients with (cases) and without (controls) proven or probable IF diagnosed in a cohort of patients with acute myeloid leukemia (AML) or myelodysplasia (MDS), and in allogeneic hematopoietic cell transplant (HCT) recipients (early, until day 40; late, after day 40 posttransplant) were compared by univariate Cox regression analysis. RESULTS: Among 237 induction remission courses of AML/MDS and 663 HCTs (345 allogeneic and 318 autologous), 25 cases of IF were diagnosed. In the AML/MDS cohort, active smoking (hazard ratio [HR], 9.11 [95% confidence interval {CI}, 2.04-40.71]) was associated with IF. Variables associated with IF in the early phase of allogeneic HCT were receipt of antithymocyte globulin (HR, 22.77 [95% CI, 4.85-101.34]), hyperglycemia (HR, 5.17 [95% CI, 1.40-19.11]), center 7 (HR, 5.15 [95% CI, 1.66-15.97]), and AML (HR, 4.38 [95% CI, 1.39-13.81]), and in the late phase were nonmyeloablative conditioning regimen (HR, 35.08 [95% CI, 3.90-315.27]), grade III/IV graft-vs-host disease (HR, 16.50 [95% CI, 2.67-102.28]), and previous invasive mold disease (HR, 10.65 [95% CI, 1.19-95.39]). CONCLUSIONS: Attempts to reduce the risk of IF may include smoking cessation, aggressive control of hyperglycemia, and the use of a mold-active agent as prophylaxis in patients receiving nonmyeloablative HCT or ATG in the conditioning regimen. Future research should further explore smoking and other prehospital variables as risks for IF.

Hyperhemolysis syndrome in patients with sickle cell anemia: report of three cases.

BACKGROUND: Sickle cell anemia (SCA) is characterized by chronic hemolytic anemia. Worsening of anemia after red blood cell (RBC) transfusion has been reported and is often referred to as hyperhemolysis syndrome (HS). HS is a severe transfusion reaction characterized by destruction of both donor and host RBCs. CASE REPORTS: In this study we report the clinical findings and treatment of three adolescent patients with SCA who presented with HS. HS occurred after exchange transfusion in two cases and after RBC transfusion during vasoocclusive crises in one. A decrease of serum hemoglobin (Hb) levels was observed 5 to 7 days after transfusions and ranged from 2.5 to 5.7 g/dL. The direct antiglobulin test was positive in two patients who also presented with alloantibodies. Patient 3 received 2 additional RBC units after the onset of HS and experienced the lowest Hb values (2.5 g/dL) shortly after. Patients received intravenous steroids as the main specific treatment and also immunoglobulin and erythropoietin. Resolution of hemolysis was observed in all cases. Of note, spleen lesions were detected in two patients, one had a normal spleen size, and the other presented with enlarged spleen. Pathophysiologic implications of these findings were discussed. CONCLUSIONS: HS must be a well-recognized complication of SCA after RBC transfusion. Prompt initiation of treatment and avoiding further transfusions may contribute to reduce the mortality associated with HS. The presence of functional spleen on the pathophysiology of HS deserves further evaluation.

Association between cationic liposomes and low molecular weight hyaluronic acid.

This work presents a study of the association between low molecular weight hyaluronic acid (16 kDa HA) and cationic liposomes composed of egg phosphatidylcholine (EPC), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP). The cationic liposome/HA complexes were evaluated to determine their mesoscopic structure, average size, zeta potential, and morphology as a function of the amount of HA in the system. Small angle X-ray scattering results revealed that neighboring cationic liposomes either stick together after a partial coating of low concentration HA or disperse completely in excess of HA, but they never assemble as multilamellar vesicles. Cryo-transmission electron microscopy images confirm the existence of unilamellar vesicles and large aggregates of unilamellar vesicles for HA fractions up to 80% (w/w). High concentrations of HA (> 20% w/w) proved to be efficient for coating extruded liposomes, leading to particle complexes with sizes in the nanoscale range and a negative zeta potential.

Active glutaminase C self-assembles into a supratetrameric oligomer that can be disrupted by an allosteric inhibitor.

The phosphate-dependent transition between enzymatically inert dimers into catalytically capable tetramers has long been the accepted mechanism for the glutaminase activation. Here, we demonstrate that activated glutaminase C (GAC) self-assembles into a helical, fiber-like double-stranded oligomer and propose a molecular model consisting of seven tetramer copies per turn per strand interacting via the N-terminal domains. The loop (321)LRFNKL(326) is projected as the major regulating element for self-assembly and enzyme activation. Furthermore, the previously identified in vivo lysine acetylation (Lys(311) in humans, Lys(316) in mouse) is here proposed as an important down-regulator of superoligomer assembly and protein activation. Bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide, a known glutaminase inhibitor, completely disrupted the higher order oligomer, explaining its allosteric mechanism of inhibition via tetramer stabilization. A direct correlation between the tendency to self-assemble and the activity levels of the three mammalian glutaminase isozymes was established, with GAC being the most active enzyme while forming the longest structures. Lastly, the ectopic expression of a fiber-prone superactive GAC mutant in MDA-MB 231 cancer cells provided considerable proliferative advantages to transformed cells. These findings yield unique implications for the development of GAC-oriented therapeutics targeting tumor metabolism.

Structural Insights into Ciona intestinalis Septins: complexes suggest a mechanism for nucleotide-dependent interfacial cross-talk.

Septins are filamentous nucleotide-binding proteins which can associate with membranes in a curvature-dependent manner leading to structural remodelling and barrier formation. Ciona intestinalis, a model for exploring the development and evolution of the chordate lineage, has only four septin-coding genes within its genome. These represent orthologues of the four classical mammalian subgroups, making it a minimalist non-redundant model for studying the modular assembly of septins into linear oligomers and thereby filamentous polymers. Here, we show that C. intestinalis septins present a similar biochemistry to their human orthologues and also provide the cryo-EM structures of an octamer, a hexamer and a tetrameric sub-complex. The octamer, which has the canonical arrangement (2-6-7-9-9-7-6-2) clearly shows an exposed NC-interface at its termini enabling copolymerization with hexamers into mixed filaments. Indeed, only combinations of septins which had CiSEPT2 occupying the terminal position were able to assemble into filaments via NC-interface association. The CiSEPT7-CiSEPT9 tetramer is the smallest septin particle to be solved by Cryo-EM to date and its good resolution (2.7Å) provides a well-defined view of the central NC-interface. On the other hand, the CiSEPT7-CiSEPT9 G-interface shows signs of fragility permitting toggling between hexamers and octamers, similar to that seen in human septins but not in yeast. The new structures provide insights concerning the molecular mechanism for cross-talk between adjacent interfaces. This indicates that C. intestinalis may represent a valuable tool for future studies, fulfilling the requirements of a complete but simpler system to understand the mechanisms behind the assembly and dynamics of septin filaments.

Functional diversification of cerato-platanins in Moniliophthora perniciosa as seen by differential expression and protein function specialization.

Cerato-platanins (CP) are small, cysteine-rich fungal-secreted proteins involved in the various stages of the host-fungus interaction process, acting as phytotoxins, elicitors, and allergens. We identified 12 CP genes (MpCP1 to MpCP12) in the genome of Moniliophthora perniciosa, the causal agent of witches' broom disease in cacao, and showed that they present distinct expression profiles throughout fungal development and infection. We determined the X-ray crystal structures of MpCP1, MpCP2, MpCP3, and MpCP5, representative of different branches of a phylogenetic tree and expressed at different stages of the disease. Structure-based biochemistry, in combination with nuclear magnetic resonance and mass spectrometry, allowed us to define specialized capabilities regarding self-assembling and the direct binding to chitin and N-acetylglucosamine (NAG) tetramers, a fungal cell wall building block, and to map a previously unknown binding region in MpCP5. Moreover, fibers of MpCP2 were shown to act as expansin and facilitate basidiospore germination whereas soluble MpCP5 blocked NAG6-induced defense response. The correlation between these roles, the fungus life cycle, and its tug-of-war interaction with cacao plants is discussed.

Toxicity and outcome of adults with acute myeloid leukemia receiving consolidation with high-dose cytarabine.

INTRODUCTION: High-dose cytarabine is considered standard of care as consolidation chemotherapy in adults with acute myeloid leukemia (AML) who are not eligible for allogeneic hematopoietic cell transplantation, but may be associated with significant toxicity. We evaluated the toxicity associated with high-dose cytarabine given as consolidation in AML patients treated at a Brazilian public hospital. METHODS: We retrospectively reviewed the charts of all patients with AML treated between 2008 and 2020 who obtained complete remission (CR) after one cycle of induction chemotherapy and received consolidation with at least one cycle of high-dose cytarabine (defined as 3 g/m2 every 12 h days 1, 3 and 5). RESULTS: Among 61 patients who received induction remission, 32 obtained CR and 28 received at least one cycle of high-dose cytarabine, for a total of 67 cycles (median 2 cycles per patient, range 1 - 4). In 45 cycles (67.2%) the patient was discharged after the end of chemotherapy, with a median of 6 days at home (range 3 - 8). Readmission occurred in 31 of the 45 cycles (68.9%). The most frequent toxicities were febrile neutropenia (56.7%), nausea and vomiting (23.9%), oral mucositis (14.9%) and diarrhea (11.9%). Bacteremia was documented in 13 cycles (34.2%). There were three cases of typhlitis and two of invasive fungal disease (aspergillosis and candidemia). Four patients died (14.3%), with two deaths considered treatment-related (candidemia and typhlitis). CONCLUSION: In the setting of a Brazilian public hospital, high-dose cytarabine as consolidation therapy is feasible, with manageable toxicity profile.

Molecular mechanism of glutaminase activation through filamentation and the role of filaments in mitophagy protection.

Glutaminase (GLS), which deaminates glutamine to form glutamate, is a mitochondrial tetrameric protein complex. Although inorganic phosphate (Pi) is known to promote GLS filamentation and activation, the molecular basis of this mechanism is unknown. Here we aimed to determine the molecular mechanism of Pi-induced mouse GLS filamentation and its impact on mitochondrial physiology. Single-particle cryogenic electron microscopy revealed an allosteric mechanism in which Pi binding at the tetramer interface and the activation loop is coupled to direct nucleophile activation at the active site. The active conformation is prone to enzyme filamentation. Notably, human GLS filaments form inside tubulated mitochondria following glutamine withdrawal, as shown by in situ cryo-electron tomography of cells thinned by cryo-focused ion beam milling. Mitochondria with GLS filaments exhibit increased protection from mitophagy. We reveal roles of filamentous GLS in mitochondrial morphology and recycling.

Risk factors for unsuccessful peripheral blood stem cell harvesting using granulocyte-colony stimulating factor mobilization in patients with multiple myeloma.

The aim of this study was to determine factors that influence unsuccessful peripheral blood stem cell (PBSC) harvesting in patients with multiple myeloma (MM). Retrospective data of 186 MM patients who received G-CSF as mobilization were analyzed. Patients with successful harvest were compared with those who failed (using 2 definitions of failure <2 and <4 CD34 cells×10(6)/mm(3)). The groups were compared regarding age, gender, body weight, baseline platelet count, receipt of radiotherapy, number of prior chemotherapy regimens, PBSC count before collection, processed and collected volume, collect replace, number of sessions and final number of PBSC collected. By multivariate analysis, a baseline platelet count <161,000 cells/mm(3) was associated with PBSC harvest lower than 2×10(6)/kg, and age >58 years was related to PBSC harvest lower than 4×10(6)/kg CD34 cells/kg. Patients with these parameters should not receive mobilization protocols with G-CSF alone. Alternative protocols should be tested in this high risk harvest failure population.

PEGylated versus Non-PEGylated pH-Sensitive Liposomes: New Insights from a Comparative Antitumor Activity Study.

PEGylated liposomes are largely studied as long-circulating drug delivery systems. Nevertheless, the addition of PEG can result in reduced interactions between liposomes and cells, hindering liposomal internalization into target cells. The presence of PEG on the surface of pH-sensitive liposomes is not advantageous in terms of biodistribution and tumor uptake, raising the question of whether the indiscriminate use of PEG benefits the formulation. In this study, two doxorubicin-loaded pH-sensitive liposomal formulations, PEGylated (Lip2000-DOX) or non-PEGylated (Lip-DOX), were prepared and characterized. Overall, the PEGylated and non-PEGylated liposomes showed no differences in size or morphology in Cryo-TEM image analysis. Specifically, DLS analysis showed a mean diameter of 140 nm, PDI lower than 0.2, and zeta potential close to neutrality. Both formulations showed an EP higher than 90%. With respect to drug delivery, Lip-DOX had better cellular uptake than Lip2000-DOX, suggesting that the presence of PEG reduced the amount of intracellular DOX accumulation. The antitumor activities of free-DOX and both liposomal formulations were evaluated in 4T1 breast tumor-bearing BALB/c mice. The results showed that Lip-DOX was more effective in controlling tumor growth than other groups, inhibiting tumor growth by 60.4%. Histological lung analysis confirmed that none of the animals in the Lip-DOX group had metastatic foci. These results support that pH-sensitive liposomes have interesting antitumor properties and may produce important outcomes without PEG.

Factors prompting early central venous catheter removal from cancer patients with candidaemia.

We evaluated clinical factors associated with early central venous catheter (CVC) removal in cancer patients with candidaemia who survived >3 days after the index blood culture. This was a retrospective cohort study from a previous candidaemia database conducted between January 2001 and June 2005. Eligible patients were those whose catheters were removed. Those who died in the first 72 h were excluded. Early CVC removal was defined as withdrawal in the first 72 h. We enrolled 164 patients with a 10.4% mortality rate. Multivariate analysis showed temporary non-tunnelled catheter type (odds ratio 5.06; 95% confidence interval 2.16-11.83) as the only variable associated with early removal. Among the 84 episodes judged not catheter-related, 52 CVCs were removed due to the need for further cancer treatment. No differences in mortality were seen among patients with early or late catheter removal. Stratified analysis showed a survival benefit (p = 0.04) of early removal among patients with a Karnofsky performance status score >60. The study shows a propensity to immediately remove short-term catheters and a tendency for early removal in patients undergoing active cancer treatment. There was no benefit of early catheter removal with regard to overall mortality. The favourable impact of early over late removal on survival among patients without significant illness merits further investigation.

Hematologic neoplasias and acromegaly.

We report a 59-year-old acromegalic woman, who presented with generalized bone pain, weakness, fatigue and foamy urine, who was found to have multiple myeloma (MM); and a 60-year-old acromegalic woman with dizziness, vomiting and abdominal pain, high blood pressure and splenomegaly that was posteriorly diagnosed as having Waldenstrom's macroglobulinemia (WM). Acromegaly is an uncommon disease and epidemiological studies have provided increasingly debated evidence that elevated IGF-I levels might enhance the neoplastic risk, and that cancers constitute the third leading cause of mortality in acromegaly. It is known that GH and IGF-I can activate B cell lymphocytes, and that IGF-I receptor is universally expressed in MM cells. Although the complication of acromegaly with WM or MM in patients has rarely been reported until now, we described two case reports of acromegalic patients with those hematological neoplasias, which allow a discussion about this controversial issue.

An atomic model for the human septin hexamer by cryo-EM.

In order to form functional filaments, human septins must assemble into hetero-oligomeric rod-like particles which polymerize end-to-end. The rules governing the assembly of these particles and the subsequent filaments are incompletely understood. Although crystallographic approaches have been successful in studying the separate components of the system, there has been difficulty in obtaining high resolution structures of the full particle. Here we report a first cryo-EM structure for a hexameric rod composed of human septins 2, 6 and 7 with a global resolution of ~3.6 Å and a local resolution of between ~3.0 Å and ~5.0 Å. By fitting the previously determined high-resolution crystal structures of the component subunits into the cryo-EM map, we are able to provide an essentially complete model for the particle. This exposes SEPT2 NC-interfaces at the termini of the hexamer and leaves internal cavities between the SEPT6-SEPT7 pairs. The floor of the cavity is formed by the two α0 helices including their polybasic regions. These are locked into place between the two subunits by interactions made with the α5 and α6 helices of the neighbouring monomer together with its polyacidic region. The cavity may serve to provide space allowing the subunits to move with respect to one another. The elongated particle shows a tendency to bend at its centre where two copies of SEPT7 form a homodimeric G-interface. Such bending is almost certainly related to the ability of septin filaments to recognize and even induce membrane curvature.

Cryo-EM structure of the mature and infective Mayaro virus at 4.4 Å resolution reveals features of arthritogenic alphaviruses.

Mayaro virus (MAYV) is an emerging arbovirus of the Americas that may cause a debilitating arthritogenic disease. The biology of MAYV is not fully understood and largely inferred from related arthritogenic alphaviruses. Here, we present the structure of MAYV at 4.4 Å resolution, obtained from a preparation of mature, infective virions. MAYV presents typical alphavirus features and organization. Interactions between viral proteins that lead to particle formation are described together with a hydrophobic pocket formed between E1 and E2 spike proteins and conformational epitopes specific of MAYV. We also describe MAYV glycosylation residues in E1 and E2 that may affect MXRA8 host receptor binding, and a molecular "handshake" between MAYV spikes formed by N262 glycosylation in adjacent E2 proteins. The structure of MAYV is suggestive of structural and functional complexity among alphaviruses, which may be targeted for specificity or antiviral activity.

Current treatment preferences in acute myeloid leukemia: a survey in Brazil.

INTRODUCTION: Most adults with acute myeloid leukemia (AML) will eventually relapse from their disease. The combination of 7-day cytarabine and an anthracycline on days 1-3 (the so called "7 + 3" regimen) can be considered standard of care of younger patients with AML. However, the treatment of the elderly ineligible for intensive chemotherapy remains a challenge. Low-dose of subcutaneous cytarabine or hypomethylating agents (HMA) have been studied this group. There are no studies investigating physician practice variation in treating AML in Brazil. METHODS: We developed a survey with ten questions in order to explore the approach to AML in Brazil. RESULTS: The sample size comprised 100 hematologists. Most reported regular (63%) or occasional (29%) treatment of AML patients. Karyotype analysis and polymerase chain reaction were available in 88% and 71% of institutions, respectively. Next generation sequencing analysis was used in 7% of instituitions. Younger patients receive the "7 + 3" protocol with continuous infusion of cytarabine and anthracycline in 98% of cases. The preferred anthracycline is daunorubicin (64%), followed by idarubicin (34%). The most prescribed daunorubicin dose was 60 mg/m2 (56%). Consolidation after CR with high cytarabine doses (HIDAC) was indicated by 84% of hematologists and 70% use 3 g/m2 twice a day for 3 days. Elderly and unfit patients received HMA (47%) as the preferred treatment. CONCLUSION: We showed that the most prevalent AML treatments were according to current guidelines. There is room to improve on the availability of diagnostic tools and the capacity to perform bone marrow transplantation.