Search

Laccases that oxidize low-density polyethylene (LDPE) represent a promising strategy for bioremediation purposes. To rationalize or optimize their PE-oxidative activity, two fundamental factors must be considered: the enzyme's redox potential and its binding affinity/mode towards LDPE. Indeed, a stable laccase-PE complex may facilitate a thermodynamically unfavorable electron transfer, even without redox mediators. In this study, we compared the redox potential and the LDPE-binding properties of three different PE-oxidizing laccases: a fungal high-redox potential laccase from Trametes versicolor, a bacterial low-redox potential laccase from Bacillus subtilis, and the recently characterized LMCO2 from Rhodococcus opacus R7. First, we measured that LMCO2 has a low potential (E°=413 mV), consistent with other bacterial variants. Using computational tools, we simulated the interactions of these laccases with a large LDPE model and highlighted the key role of hydrophobic residues surrounding the T1 site. Notably, a methionine-rich loop in LMCO2 appears to enhance the formation of a stable complex with LDPE, potentially facilitating electron transfer. This study underscores the necessity for comprehensive computational strategies to analyze enzyme-polymer interactions beyond simplistic models, uncovering critical binding determinants and informing future mutagenesis experiments, in order to enhance laccase performance and rationalize variations in enzymatic activity., (© 2025 Wiley‐VCH GmbH.)

The identification of the coproporphyrin-dependent heme biosynthetic pathway, which is used almost exclusively by monoderm bacteria in 2015 by Dailey et al. triggered studies aimed at investigating the enzymes involved in this pathway that were originally assigned to the protoporphyrin-dependent heme biosynthetic pathway. Here, we revisit the active site of coproporphyrin ferrochelatase by a biophysical and biochemical investigation using the physiological substrate coproporphyrin III, which in contrast to the previously used substrate protoporphyrin IX has four propionate substituents and no vinyl groups. In particular, we have compared the reactivity of wild-type coproporphyrin ferrochelatase from the firmicute Listeria monocytogenes with those of variants, namely, His182Ala (H182A) and Glu263Gln (E263Q), involving two key active site residues. Interestingly, both variants are active only toward the physiological substrate coproporphyrin III but inactive toward protoporphyrin IX. In addition, E263 exchange impairs the final oxidation step from ferrous coproheme to ferric coproheme. The characteristics of the active site in the context of the residues involved and the substrate binding properties are discussed here using structural and functional means, providing a further contribution to the deciphering of this enigmatic reaction mechanism., (© 2024 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

The cleavage of the axial S(Met) - Fe bond in cytochrome c (cytc) upon binding to cardiolipin (CL), a glycerophospholipid of the inner mitochondrial membrane, is one of the key molecular changes that impart cytc with (lipo)peroxidase activity essential to its pro-apoptotic function. In this work, UV - VIS, CD, MCD and fluorescence spectroscopies were used to address the role of the Fe - M80 bond in controlling the cytc-CL interaction, by studying the binding of the Met80Ala (M80A) variant of S. cerevisiae iso-1 cytc (ycc) to CL liposomes in comparison with the wt protein [Paradisi et al. J. Biol. Inorg. Chem. 25 (2020) 467-487]. The results show that the integrity of the six-coordinate heme center along with the distal heme site containing the Met80 ligand is a not requisite for cytc binding to CL. Indeed, deletion of the Fe - S(Met80) bond has a little impact on the mechanism of ycc-CL interaction, although it results in an increased heme accessibility to solvent and a reduced structural stability of the protein. In particular, M80A features a slightly tighter binding to CL at low CL/cytc ratios compared to wt ycc, possibly due to the lift of some constraints to the insertion of the CL acyl chains into the protein hydrophobic core. M80A binding to CL maintains the dependence on the CL-to-cytc mixing scheme displayed by the wt species., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Treatment of diffuse large B-cell lymphoma (DLBCL) in older patients is challenging, especially for those who are not eligible for anthracycline-containing regimens. Fondazione Italiana Linfomi (FIL) started the FIL_ReRi study, a 2-stage single-arm trial to investigate the activity and safety of the chemo-free combination of rituximab and lenalidomide (R2) in ≥70-year-old untreated frail patients with DLBCL. Frailty was prospectively defined using a simplified geriatric assessment tool. Patients were administered a maximum of 6 28-day cycles of 20 mg oral lenalidomide from days 2 to 22 and IV rituximab 375 mg/m2 on day 1, with response assessment after cycles 4 and 6. Patients with partial response or complete response (CR) at cycle 6 were administered lenalidomide 10 mg/d from days 1 to 21 for every 28 cycles for a total of 12 cycles or until progression or unacceptable toxicity. The primary end point was the overall response rate (ORR) after cycle 6; the coprimary end point was the rate of grade 3 or 4 extrahematological toxicity. The ORR was 50.8%, with 27.7% CR. After a median follow-up of 24 months, the median progression-free survival was 14 months, and the 2-year duration of response was 64%. Thirty-four patients experienced extrahematological toxicity according to the National Cancer Institute Common Terminology Criteria for Adverse Events grade ≥3. The activity of the R2 combination was observed in a significant proportion of subjects, warranting further exploration of a chemo-free approach in frail older patients with DLBCL. This trial was registered at EudraCT as #2015-003371-29 and clinicaltrials.gov as #NCT02955823., (© 2023 by The American Society of Hematology.)

The heme enzyme chlorite dismutase (Cld) catalyzes the degradation of chlorite to chloride and dioxygen. Many questions about the molecular reaction mechanism of this iron protein have remained unanswered, including the electronic nature of the catalytically relevant oxoiron(IV) intermediate and its interaction with the distal, flexible, and catalytically active arginine. Here, we have investigated the dimeric Cld from Cyanothece sp. PCC7425 ( C Cld) and two variants having the catalytic arginine R127 (i) hydrogen-bonded to glutamine Q74 (wild-type C Cld), (ii) arrested in a salt bridge with a glutamate (Q74E), or (iii) being fully flexible (Q74V). Presented stopped-flow spectroscopic studies demonstrate the initial and transient appearance of Compound I in the reaction between C Cld and chlorite at pH 5.0 and 7.0 and the dominance of spectral features of an oxoiron(IV) species (418, 528, and 551 nm) during most of the chlorite degradation period at neutral and alkaline pH. Arresting the R127 in a salt bridge delays chlorite decomposition, whereas increased flexibility accelerates the reaction. The dynamics of R127 does not affect the formation of Compound I mediated by hypochlorite but has an influence on Compound I stability, which decreases rapidly with increasing pH. The decrease in activity is accompanied by the formation of protein-based amino acid radicals. Compound I is demonstrated to oxidize iodide, chlorite, and serotonin but not hypochlorite. Serotonin is able to dampen oxidative damage and inactivation of C Cld at neutral and alkaline pH. Presented data are discussed with respect to the molecular mechanism of Cld and the pronounced pH dependence of chlorite degradation.

Peripheral T-cell lymphomas (PTCL) are a heterogeneous group of rare lymphoid malignancies that mostly have poor prognoses with currently available treatments. Upfront consolidation with autologous stem cell transplantation (ASCT) is frequently carried out, but its efficacy has never been investigated in randomized trials. We designed a multicenter, international, retrospective study with the main objective of comparing progression-free survival and overall survival of patients with PTCL who underwent ASCT in complete remission (CR) after first-line chemotherapy with a control group who did not undergo ASCT. From the initial population of 286 registered patients, 174 patients with PTCL other than anaplastic large cell lymphoma, ALK-positive, deemed fit for ASCT at the time of diagnosis, and who were in CR or uncertain CR after induction therapy (CR1) were included in our analysis. one hundred and three patients underwent ASCT, whereas 71 did not, in most cases (n=53) because the physician decided against it. With a median follow-up of 65.5 months, progression-free survival was significantly better in the transplanted patients than in the non-transplanted group: 63% versus 48% at 5 years (P=0.042). Overall survival was significantly longer for ASCT patients in the subgroup with advanced stage at diagnosis (5-year overall survival: 70% vs. 50%, P=0.028). In the multivariate analysis, first-line ASCT was associated with significantly prolonged progression-free survival (HR=0.57, 95% CI: 0.35-0.93) and overall survival (HR=0.57, 95% CI: 0.33-0.99). In conclusion, our study supports the use of ASCT as a consolidation strategy for patients with PTCL in CR1. These results should be confirmed in a prospective randomized study.

Pseudomonas putida W619 is a soil Gram-negative bacterium commonly used in environmental studies thanks to its ability in degrading many aromatic compounds. Its genome contains several putative carbohydrate-active enzymes such as glycoside hydrolases and lytic polysaccharide monooxygenases (PMOs). In this study, we have heterologously produced in Escherichia coli and characterized a new enzyme belonging to the AA10 family, named PpAA10 (Uniprot: B1J2U9), which contains a chitin-binding type-4 module and showed activity toward β-chitin. The active form of the enzyme was produced in E. coli exploiting the addition of a cleavable N-terminal His tag which ensured the presence of the copper-coordinating His as the first residue. Electron paramagnetic resonance spectroscopy showed signal signatures similar to those observed for the copper-binding site of chitin-cleaving PMOs. The protein was used to develop a versatile, highly sensitive, cost-effective and easy-to-apply method to detect PMO's activity exploiting attenuated total reflection-Fourier transform infrared spectroscopy and able to easily discriminate between different substrates., (© 2021 The Protein Society.)

Anaplastic lymphoma kinase-negative anaplastic large cell lymphoma (ALK- ALCL) is an aggressive neoplasm of T-cell/null-cell lineage. The T-Cell Project is a global prospective cohort study that consecutively enrolled patients newly diagnosed with peripheral T-cell lymphoma, registered through a centralized computer database between September 2006 and February 2018. Of 1553 validated cases from 74 sites in 13 countries worldwide, 235 were reported as ALK- ALCL. The median age at diagnosis was 54 years (range, 18-89 years), with a male predominance (62%). Stage III to IV disease was identified in 71% of patients, bulky disease and bone marrow involvement were uncommon, and 66% of patients presented with a low (0-1) International Prognostic Index score. Of all treated patients, 85% received multiagent initial chemotherapy, and 8% were consolidated with autologous hematopoietic cell transplantation. The initial overall and complete response rates were 77% and 63%, respectively. After a median follow-up of 52 months (95% confidence interval [CI], 41-63), the median progression-free survival (PFS) and overall survival (OS) were 41 months (95% CI, 17-62) and 55 months (95% CI, 36-75), respectively. The 3- and 5-year PFS rates were 52% and 43%, and the 3- and 5-year OS rates were 60% and 49%. Treatments containing both anthracycline and etoposide were associated with superior OS (P = .05) but not PFS (P = .18). In this large prospective cohort study, outcomes comparable to those previously reported in the retrospective International Peripheral T-Cell Lymphoma Project were observed. The study underscores the need for introducing novel platforms for ALK- ALCL and establishes a benchmark for future clinical trials. This trial was registered at www.clinicaltrials.gov as #NCT01142674., (© 2021 by The American Society of Hematology.)

Purpose: We explored the potential overall survival (OS) benefit of bleomycin, etoposide, doxorubicin (Adriamycin), cyclophosphamide, vincristine (Oncovin), procarbazine, and prednisone (BEACOPP) over doxorubicin (Adriamycin), bleomycin, vinblastine, and dacarbazine (ABVD) in a pooled analysis of four randomized trials., Patients and Methods: Primary objective was to evaluate the OS impact of BEACOPP using individual patient data. Secondary objectives were progression-free survival (PFS), secondary cancers, and use of autologous stem cell transplantation (ASCT)., Results: About 1227 patients were included. The 7-year OS was 84.3% (95% CI 80.8-87.2) for ABVD vs 87.7% (95% CI 84.5-90.2) for BEACOPP. Two follow-up periods were identified based on survival curves and hazard ratio (HR) over time. For the first 18 months, there was no difference. For the second period of ≥18 months, ABVD patients had a higher death risk (HR ABVD vs BEACOPP  = 1.59; 95% CI 1.09-2.33). A Cox model stratified by trial and evaluating the effect of treatment and International Prognostic Index (IPI) score as fixed effects showed that both were statistically significant (treatment, P = .0185; IPI score, P = .0107). The 7-year PFS was 71.1% (95% CI 67.1-74.6) for ABVD vs 81.1% (95% CI 77.5-84.2) for BEACOPP (P < .001). After ABVD, 25 secondary cancers (4.0%) were reported with no myelodysplasia (MDS)/acute myeloid leukemia (AML) compared to 36 (6.5%) after BEACOPP, which included 13 patients with MDS/AML. Following ABVD, 86 patients (13.8%) received ASCT vs 39 (6.4%) for BEACOPP., Conclusions: This analysis showed a slight improvement in OS for BEACOPP and confirmed a PFS benefit. Frontline use of BEACOPP instead of ABVD increased secondary leukemia incidence but halved the requirement for ASCT., (© 2020 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

The interaction of cytochrome c with cardiolipin (CL) is a critical step in the initial stages of apoptosis and is mediated by a positively charged region on the protein surface comprising several lysine residues (site A). Here, the interaction of wt S. cerevisiae cytochrome c (ycc) and its K72A/K73A, K72A/K79A, K73A/K79A and K72A/K73A/K79A variants with CL was studied through UV-Vis and MCD spectroscopies at pH 7 and molecular dynamics (MD) simulations, to clarify the role of the mutated lysines. Moreover, the influence of the lipid to protein ratio on the interaction mechanism was investigated using low (0.5-10) and high (5-60) CL/ycc molar ratios, obtained with small and gradual or large and abrupt CL additions, respectively. Although all proteins bind to CL, switching from the native low-spin His/Met-ligated form to a low-spin bis-His conformer and to a high-spin species at larger CL concentrations, the two schemes of CL addition show relevant differences in the CL/ycc molar ratios at which the various conformers appear, due to differences in the interaction mechanism. Extended lipid anchorage and peripheral binding appear to prevail at low and high CL/ycc molar ratios, respectively. Simultaneous deletion of two or three surface positive charges from Site A does not abolish CL binding, but instead increases protein affinity for CL. MD calculations suggest this unexpected behavior results from the mutation-induced severe weakening of the H-bond connecting the N ε of His26 with the backbone oxygen of Glu44, which lowers the conformational stability compared to the wt species, overcoming the decreased surface electrostatic interaction.

The T Cell Project was the largest prospective trial to explore the incidence, treatment patterns, and outcomes for T cell lymphomas. The rare subtypes of T cell lymphomas, including hepatosplenic T cell lymphoma (HSTCL), enteropathy associated T cell lymphoma (EATL), and peripheral gamma delta T cell lymphomas (PGDTCLs) are poorly represented in most studies and there is little data regarding treatment patterns. We report results from 115 patients with hepatosplenic (n = 31), enteropathy associated (n = 65), and PGDTCLs (n = 19). While anthracycline regimens were most commonly used as first line therapy, response rates ranged from 20%-40% and were suboptimal for all groups. Autologous stem cell transplantation was performed as a consolidation in first remission in a small number of patients (33% of HSTCL, 7% of EATL, and 12% of PGDTCL), and four patients with HSTCL underwent allogeneic stem cell transplantation in first remission. The progression free survival at 3 years ranged from 28%-40% for these rare subtypes, and the overall survival at 3 years was most favorable for PGDTCL (70%). These data highlight the need for novel treatment approaches for rare subtypes of T cell lymphomas and for their inclusion in clinical trials., (© 2019 Wiley Periodicals, Inc.)

With >5000 annotated genes dye-decolorizing peroxidases (DyPs) represent a heme b peroxidase family of broad functional diversity. Bacterial B-class DyPs are poor peroxidases of unknown physiological function. Hydrogen peroxide efficiently mediates the rapid formation of Compound I in B-class DyPs, which, however, is stable and shows modest reactivity towards organic and inorganic electron donors. To understand these characteristics, we have investigated the redox thermodynamics of the one-electron reduction of the ferric high-spin form of wild-type B-class DyP from the pathogenic bacterium Klebsiella pneumoniae (KpDyP) and the variants D143A, R232A and D143A/R232A. These distal amino acids are fully conserved in all DyPs and play important roles in Compound I formation and maintenance of the heme cavity architecture and substrate access route(s). The E°' values of the respective redox couples Fe(III)/Fe(II) varied from -350 mV (wild-type KpDyP) to -299 mV (D143A/R232A) at pH 7.0. Variable-temperature spectroelectrochemical experiments revealed that the reduction reaction of B-class DyPs is enthalpically unfavored but entropically favored with significant differences in enthalpic and entropic contributions to E°' between the four proteins. Molecular dynamics simulations demonstrated the impact of solvent reorganization on the entropy change during reduction reaction and revealed the dynamics and restriction of substrate access channels. Obtained data are discussed with respect to the poor peroxidase activities of B-class DyPs and compared with heme peroxidases from other (super)families as well as with chlorite dismutases, which do not react with hydrogen peroxide but share a similar fold and heme cavity architecture., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Myoglobin, encoded by MB, is a small cytoplasmic globular hemoprotein highly expressed in cardiac myocytes and oxidative skeletal myofibers. Myoglobin binds O 2, facilitates its intracellular transport and serves as a controller of nitric oxide and reactive oxygen species. Here, we identify a recurrent c.292C>T (p.His98Tyr) substitution in MB in fourteen members of six European families suffering from an autosomal dominant progressive myopathy with highly characteristic sarcoplasmic inclusions in skeletal and cardiac muscle. Myoglobinopathy manifests in adulthood with proximal and axial weakness that progresses to involve distal muscles and causes respiratory and cardiac failure. Biochemical characterization reveals that the mutant myoglobin has altered O 2 binding, exhibits a faster heme dissociation rate and has a lower reduction potential compared to wild-type myoglobin. Preliminary studies show that mutant myoglobin may result in elevated superoxide levels at the cellular level. These data define a recognizable muscle disease associated with MB mutation.

Splenectomy in addition to immunotherapy with rituximab can provide quick and sometimes durable disease control in patients with splenic marginal zone lymphoma (SMZL). However, systemic chemotherapy is ultimately required in many cases. The BRISMA (Bendamustine-rituximab as first-line treatment of splenic marginal zone lymphoma)/IELSG (International Extranodal Lymphoma Study Group)36 trial is an open-label, single arm phase II study designed by the IELSG in cooperation with the Fondazione Italiana Linfomi and the lymphoma Study Association according to Simon's two-stage method. The primary endpoint was complete response rate. Fifty-six patients with SMZL diagnosis confirmed on central revision were treated with bendamustine (90 mg/m 2  days 1, 2) and rituximab (375 mg/m 2  day 1) every 28 days for six cycles (B-R). The overall response and CR rates were 91% and 73%, respectively. Duration of response, progression-free survival and overall survival at 3 years were 93% (95% confidence interval [CI] 81-98), 90% (95% CI 77-96) and 96% (95% CI 84-98), respectively. Toxicity was mostly haematological. Neutropenia grade ≥3 was recorded in 43% of patients; infections and febrile neutropenia in 5·4% and 3·6%. Overall, 14 patients (25%) experienced serious adverse events. Five patients (9%) went off-study because of toxicity and one patient died from infection. In conclusion, B-R resulted in a very effective first-line regimen for SMZL. Based on the results achieved in the BRISMA trial, B-R should be considered when a chemotherapy combination with rituximab is deemed necessary for symptomatic SMZL patients., (© 2018 British Society for Haematology and John Wiley & Sons Ltd.)

Dye-decolorizing peroxidases (DyPs) represent the most recently classified hydrogen peroxide-dependent heme peroxidase family. Although widely distributed with more than 5000 annotated genes and hailed for their biotechnological potential, detailed biochemical characterization of their reaction mechanism remains limited. Here, we present the high-resolution crystal structures of WT B-class DyP from the pathogenic bacterium Klebsiella pneumoniae ( Kp DyP) (1.6 Å) and the variants D143A (1.3 Å), R232A (1.9 Å), and D143A/R232A (1.1 Å). We demonstrate the impact of elimination of the DyP-typical, distal residues Asp-143 and Arg-232 on (i) the spectral and redox properties, (ii) the kinetics of heterolytic cleavage of hydrogen peroxide, (iii) the formation of the low-spin cyanide complex, and (iv) the stability and reactivity of an oxoiron(IV)porphyrin π-cation radical (Compound I). Structural and functional studies reveal that the distal aspartate is responsible for deprotonation of H 2 O 2 and for the poor oxidation capacity of Compound I. Elimination of the distal arginine promotes a collapse of the distal heme cavity, including blocking of one access channel and a conformational change of the catalytic aspartate. We also provide evidence of formation of an oxoiron(IV)-type Compound II in Kp DyP with absorbance maxima at 418, 527, and 553 nm. In summary, a reaction mechanism of the peroxidase cycle of B-class DyPs is proposed. Our observations challenge the idea that peroxidase activity toward conventional aromatic substrates is related to the physiological roles of B-class DyPs., (© 2018 Pfanzagl et al.)

An important unmet need in the management of primary mediastinal B-cell lymphoma (PMBCL) is to identify the patients for whom first-line therapy will fail to intervene before the lymphoma becomes refractory. High heterogeneity of intratumoral 18 F-fluorodeoxyglucose (18FDG) uptake distribution on positron emission tomography/computed tomography (PET/CT) scans has been suggested as a possible marker of chemoresistance in solid tumors. In the present study, we investigated the prognostic value of metabolic heterogeneity (MH) in 103 patients with PMBCL prospectively enrolled in the International Extranodal Lymphoma Study Group (IELSG) 26 study, aimed at clarifying the role of PET in this lymphoma subtype. MH was estimated using the area under curve of cumulative standardized uptake value-volume histogram (AUC-CSH) method. Progression-free survival at 5 years was 94% vs 73% in low- and high-MH groups, respectively ( P = .0001). In a Cox model of progression-free survival including dichotomized MH, metabolic tumor volume, total lesion glycolysis (TLG), international prognostic index, and tumor bulk (mediastinal mass > 10 cm), as well as age as a continuous variable, only TLG ( P < .001) and MH ( P < .001) retained statistical significance. Using these 2 features to construct a simple prognostic model resulted in early and accurate (positive predictive value, 89%; negative predictive value, ≥90%) identification of patients at high risk for progression at a point that would allow the use of risk-adapted treatments. This may provide an important opportunity for the design of future trials aimed at helping the minority of patients who harbor chemorefractory PMBCL. The study is registered at ClinicalTrials.gov as NCT00944567., (© 2018 by The American Society of Hematology.)

This analysis explored factors influencing survival of patients with primary refractory and relapsed peripheral T-cell lymphomas enrolled in the prospective International T-cell Project. We analyzed data from 1020 patients with newly diagnosed disease, enrolled between September 2006 and December 2015. Out of 937 patients who received first-line treatment, 436 (47%) were identified as refractory and 197 (21%) as relapsed. Median time from the end of treatment to relapse was 8 months (range 2-73). Overall, 75 patients (8%) were consolidated with bone marrow transplantation, including 12 refractory and 22 relapsed patients. After a median follow up of 38 months (range 1-96 months) from documentation of refractory/relapsed disease, 440 patients had died. The median overall survival (OS) was 5.8 months; 3-year overall survival rates were 21% and 28% for refractory and relapsed patients, respectively ( P <0.001). Patients receiving or not salvage bone marrow transplantation had a 3-year survival of 48% and 18%, respectively ( P <0.001). In a univariate Cox regression analysis, refractory disease was associated with a higher risk of death (HR=1.43, P =0.001), whereas late relapse (>12 months, HR 0.57, P =0.001) and salvage therapy with transplantation (HR=0.36, P <0.001) were associated with a better OS. No difference was found in OS with respect to histology. This study accurately reflects outcomes for patients treated according to standards of care worldwide. Results confirm that peripheral T-cell lymphomas patients had dismal outcome after relapse or progression. Patients with chemotherapy sensitive disease who relapsed after more than 12 months might benefit from consolidation bone marrow transplantation., (Copyright© 2018 Ferrata Storti Foundation.)

Different models to investigate the prognosis of peripheral T cell lymphoma not otherwise specified (PTCL-NOS) have been developed by means of retrospective analyses. Here we report on a new model designed on data from the prospective T Cell Project. Twelve covariates collected by the T Cell Project were analysed and a new model (T cell score), based on four covariates (serum albumin, performance status, stage and absolute neutrophil count) that maintained their prognostic value in multiple Cox proportional hazards regression analysis was proposed. Among patients registered in the T Cell Project, 311 PTCL-NOS were retained for study. At a median follow-up of 46 months, the median overall survival (OS) and progression-free survival (PFS) was 20 and 10 months, respectively. Three groups were identified at low risk (LR, 48 patients, 15%, score 0), intermediate risk (IR, 189 patients, 61%, score 1-2), and high risk (HiR, 74 patients, 24%, score 3-4), having a 3-year OS of 76% [95% confidence interval 61-88], 43% [35-51], and 11% [4-21], respectively (P < 0·001). Comparing the performance of the T cell score on OS to that of each of the previously developed models, it emerged that the new score had the best discriminant power. The new T cell score, based on clinical variables, identifies a group with very unfavourable outcomes., (© 2018 The Authors. British Journal of Haematology published by John Wiley & Sons Ltd.)

We tested baseline positron emission tomography (PET)/computed tomography (CT) as a measure of total tumor burden to better identify high-risk patients with early-stage Hodgkin lymphoma (HL). Patients with stage I-II HL enrolled in the standard arm (combined modality treatment) of the H10 trial (NCT00433433) with available baseline PET and interim PET (iPET2) after 2 cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine were included. Total metabolic tumor volume (TMTV) was measured on baseline PET. iPET2 findings were reported negative (DS1-3) or positive (DS4-5) with the Deauville scale (DS). The prognostic value of TMTV was evaluated and compared with baseline characteristics, staging classifications, and iPET2. A total of 258 patients were eligible: 101 favorable and 157 unfavorable. The median follow-up was 55 months, with 27 progression-free survival (PFS) and 12 overall survival (OS) events. TMTV was a prognosticator of PFS ( P < .0001) and OS ( P = .0001), with 86% and 84% specificity, respectively. Five-year PFS and OS were 71% and 83% in the high-TMTV (>147 cm 3 ) group (n = 46), respectively, vs 92% and 98% in the low-TMTV group (≤147 cm 3 ). In multivariable analysis including iPET2, TMTV was the only baseline prognosticator compared with the current staging systems proposed by the European Organization for Research and Treatment of Cancer/Groupe d'Etude des Lymphomes de l'Adulte, German Hodgkin Study Group, or National Comprehensive Cancer Network. TMTV and iPET2 were independently prognostic and, combined, identified 4 risk groups: low (TMTV≤147+DS1-3; 5-year PFS, 95%), low-intermediate (TMTV>147+DS1-3; 5-year PFS, 81.6%), high-intermediate (TMTV≤147+DS4-5; 5-year PFS, 50%), and high (TMTV>147+DS4-5; 5-year PFS, 25%). TMTV improves baseline risk stratification of patients with early-stage HL compared with current staging systems and the predictive value of early PET response as well., (© 2018 by The American Society of Hematology.)

Oxidation of halides and thiocyanate by heme peroxidases to antimicrobial oxidants is an important cornerstone in the innate immune system of mammals. Interestingly, phylogenetic and physiological studies suggest that homologous peroxidases are already present in mycetozoan eukaryotes such as Dictyostelium discoideum This social amoeba kills bacteria via phagocytosis for nutrient acquisition at its single-cell stage and for antibacterial defense at its multicellular stages. Here, we demonstrate that peroxidase A from D. discoideum (DdPoxA) is a stable, monomeric, glycosylated, and secreted heme peroxidase with homology to mammalian peroxidases. The first crystal structure (2.5 Å resolution) of a mycetozoan peroxidase of this superfamily shows the presence of a post-translationally-modified heme with one single covalent ester bond between the 1-methyl heme substituent and Glu-236. The metalloprotein follows the halogenation cycle, whereby compound I oxidizes iodide and thiocyanate at high rates (>10 8 m -1 s -1 ) and bromide at very low rates. It is demonstrated that DdPoxA is up-regulated and likely secreted at late multicellular development stages of D. discoideum when migrating slugs differentiate into fruiting bodies that contain persistent spores on top of a cellular stalk. Expression of DdPoxA is shown to restrict bacterial contamination of fruiting bodies. Structure and function of DdPoxA are compared with evolutionary-related mammalian peroxidases in the context of non-specific immune defense., (© 2018 by The American Society for Biochemistry and Molecular Biology, Inc.)

Neuroglobin is a monomeric globin containing a six-coordinate heme b, expressed in the nervous system, which exerts an important neuroprotective role. In the human protein (hNgb), Cys46 and Cys55 form an intramolecular disulfide bond under oxidizing conditions, whose cleavage induces a helix-to-strand rearrangement of the CD loop that strengthens the bond between the heme iron and the distal histidine. Hence, it is conceivable that the intramolecular disulfide bridge modulates the functionality of human neuroglobin by controlling exogenous ligand binding. In this work, we investigated the influence of the Cys46/Cys55 disulfide bond on the redox properties and on the pH-dependent conformational equilibria of hNgb, using UV-vis spectroelectrochemistry, cyclic voltammetry, electronic absorption spectroscopy and magnetic circular dichroism (MCD). We found that the SS bridge significantly affects the heme Fe(III) to Fe(II) reduction enthalpy (ΔH°' rc ) and entropy (ΔS°' rc ), mostly as a consequence of changes in the reduction-induced solvent reorganization effects, without affecting the axial ligand-binding interactions and the polarity and electrostatics of the heme environment. Between pH3 and 12, the electronic properties of the heme of ferric hNgb are sensitive to five acid-base equilibria, which are scarcely affected by the Cys46/Cys55 disulfide bridge. The equilibria occurring at extreme pH values induce heme release, while those occurring between pH5 and 10 alter the electronic properties of the heme without modifying its axial coordination and low spin state. They involve the sidechains of non-coordinating aminoacids close to the heme and at least one heme propionate., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Peripheral T-cell lymphomas (PTCLs) comprise a heterogeneous group of neoplasms that are derived from post-thymic lymphoid cells at different stages of differentiation with different morphological patterns, phenotypes and clinical presentations. PTCLs are highly diverse, reflecting the diverse cells from which they can originate and are currently sub-classified using World Health Organization (WHO) 2008 criteria. In 2006 the International T-Cell Lymphoma Project launched the T-Cell Project, building on the retrospective study previously carried on by the network, with the aim to prospectively collect accurate data to improve knowledge on this group of lymphomas. Based on previously published reports from International Study Groups it emerged that rendering a correct classification of PTCLs is quite difficult because the relatively low prevalence of these diseases results in a lack of confidence by most pathologists. This is the reason why the T-Cell Project requested the availability of diagnostic material from the initial biopsy of each patient registered in the study in order to have the initial diagnosis centrally reviewed by expert hematopathologists. In the present report the results of the review process performed on 573 cases are presented. Overall, an incorrect diagnosis was centrally recorded in 13.1% cases, including 8.5% cases centrally reclassified with a subtype eligible for the project and 4.6% cases misclassified and found to be disorders other than T-cell lymphomas; 2.1% cases were centrally classified as T-Cell disorders not included in the study population. Thus, the T-Cell Project confirmed the difficulties in providing an accurate classification when a diagnosis of PTCLs is suspected, singled out the major pitfalls that can bias a correct histologic categorization and confirmed that a centralized expert review with the application of adequate diagnostic algorithms is mandatory when dealing with these tumours. Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)

The heme enzyme chlorite dismutase (Cld) catalyzes the degradation of chlorite to chloride and dioxygen. Although structure and steady-state kinetics of Clds have been elucidated, many questions remain (e.g., the mechanism of chlorite cleavage and the pH dependence of the reaction). Here, we present high-resolution X-ray crystal structures of a dimeric Cld at pH 6.5 and 8.5, its fluoride and isothiocyanate complexes and the neutron structure at pH 9.0 together with the pH dependence of the Fe(III)/Fe(II) couple, and the UV-vis and resonance Raman spectral features. We demonstrate that the distal Arg127 cannot act as proton acceptor and is fully ionized even at pH 9.0 ruling out its proposed role in dictating the pH dependence of chlorite degradation. Stopped-flow studies show that (i) Compound I and hypochlorite do not recombine and (ii) Compound II is the immediately formed redox intermediate that dominates during turnover. Homolytic cleavage of chlorite is proposed.

Treatment intensification to maximize disease control and reduced intensity approaches to minimize the risk of late sequelae have been evaluated in newly diagnosed Hodgkin lymphoma. The influence of these interventions on the risk of secondary malignant neoplasms, progression-free survival and overall survival is reported in the meta-analysis herein, based on individual patient data from 9498 patients treated within 16 randomized controlled trials for newly diagnosed Hodgkin lymphoma between 1984 and 2007. Secondary malignant neoplasms were meta-analyzed using Peto's method as time-to-event outcomes. For progression-free and overall survival, hazard ratios derived from each trial using Cox regression were combined by inverse-variance weighting. Five study questions (combined-modality treatment vs. chemotherapy alone; more extended vs. involved-field radiotherapy; radiation at higher doses vs. radiation at 20 Gy; more vs. fewer cycles of the same chemotherapy protocol; standard-dose chemotherapy vs. intensified chemotherapy) were investigated. After a median follow-up of 7.4 years, dose-intensified chemotherapy resulted in better progression-free survival rates ( P =0.007) as compared with standard-dose chemotherapy, but was associated with an increased risk of therapy-related acute myeloid leukemia/myelodysplastic syndromes ( P =0.0028). No progression-free or overall survival differences were observed between combined-modality treatment and chemotherapy alone, but more secondary malignant neoplasms were seen after combined-modality treatment ( P =0.010). For the remaining three study questions, outcomes and secondary malignancy rates did not differ significantly between treatment strategies. The results of this meta-analysis help to weigh up efficacy and secondary malignancy risk for the choice of first-line treatment for Hodgkin lymphoma patients. However, final conclusions regarding secondary solid tumors require longer follow-up., (Copyright© 2017 Ferrata Storti Foundation.)

The existence of covalent heme to protein bonds is the most striking structural feature of mammalian peroxidases, including myeloperoxidase and lactoperoxidase (LPO). These autocatalytic posttranslational modifications (PTMs) were shown to strongly influence the biophysical and biochemical properties of these oxidoreductases. Recently, we reported the occurrence of stable LPO-like counterparts with two heme to protein ester linkages in bacteria. This study focuses on the model wild-type peroxidase from the cyanobacterium Lyngbya sp. PCC 8106 (LspPOX) and the mutants D109A, E238A, and D109A/E238A that could be recombinantly produced as apoproteins in Escherichia coli, fully reconstituted to the respective heme b proteins, and posttranslationally modified by hydrogen peroxide. This for the first time allows not only a direct comparison of the catalytic properties of the heme b and PTM forms but also a study of the impact of D109 and E238 on PTM and catalysis, including Compound I formation and the two-electron reduction of Compound I by bromide, iodide, and thiocyanate. It is demonstrated that both heme to protein ester bonds can form independently and that elimination of E238, in contrast to exchange of D109, does not cause significant structural rearrangements or changes in the catalytic properties neither in heme b nor in the PTM form. The obtained findings are discussed with respect to published structural and functional data of human peroxidases.

Purpose There is no consensus on the optimal systemic treatment of patients with extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue. The IELSG-19 phase III study, to our knowledge, was the first such study to address the question of first-line treatment in a randomized trial. Patients and Methods Eligible patients were initially randomly assigned (1:1 ratio) to receive either chlorambucil monotherapy (6 mg/m 2 /d orally on weeks 1 to 6, 9 to 10, 13 to 14, 17 to 18, and 21 to 22) or a combination of chlorambucil (same schedule as above) and rituximab (375 mg/m 2 intravenously on day 1 of weeks 1, 2, 3, 4, 9, 13, 17, and 21). After the planned enrollment of 252 patients, the protocol was amended to continue with a three-arm design (1:1:6 ratio), with a new arm that included rituximab alone (same schedule as the combination arm) and with a final sample size of 454 patients. The main end point was event-free survival (EFS). Analysis of chlorambucil versus the combination arm was performed and reported separately before any analysis of the third arm. Results At a median follow-up of 7.4 years, addition of rituximab to chlorambucil led to significantly better EFS (hazard ratio, 0.54; 95% CI, 0.38 to 0.77). EFS at 5 years was 51% (95% CI, 42 to 60) with chlorambucil alone, 50% (95% CI, 42 to 59) with rituximab alone, and 68% (95% CI, 60 to 76) with the combination ( P = .0009). Progression-free survival was also significantly better with the combination ( P = .0119). Five-year overall survival was approximately 90% in each arm. All treatments were well tolerated. No unexpected toxicities were recorded. Conclusion Rituximab in combination with chlorambucil demonstrated superior efficacy in mucosa-associated lymphoid tissue lymphoma; however, improvements in EFS and progression-free survival did not translate into longer overall survival.

Purpose Patients who receive combined modality treatment for stage I and II Hodgkin lymphoma (HL) have an excellent outcome. Early response evaluation with positron emission tomography (PET) scan may improve selection of patients who need reduced or more intensive treatments. Methods We performed a randomized trial to evaluate treatment adaptation on the basis of early PET (ePET) after two cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) in previously untreated-according to European Organisation for Research and Treatment of Cancer criteria favorable (F) and unfavorable (U)-stage I and II HL. The standard arm consisted of ABVD followed by involved-node radiotherapy (INRT), regardless of ePET result. In the experimental arm, ePET-negative patients received ABVD only (noninferiority design), whereas ePET-positive patients switched to two cycles of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPPesc) and INRT (superiority design). Primary end point was progression-free survival (PFS). Results Of 1,950 randomly assigned patients, 1,925 received an ePET-361 patients (18.8%) were positive. In ePET-positive patients, 5-year PFS improved from 77.4% for standard ABVD + INRT to 90.6% for intensification to BEACOPPesc + INRT (hazard ratio [HR], 0.42; 95% CI, 0.23 to 0.74; P = .002). In ePET-negative patients, 5-year PFS rates in the F group were 99.0% versus 87.1% (HR, 15.8; 95% CI, 3.8 to 66.1) in favor of ABVD + INRT; the U group, 92.1% versus 89.6% (HR, 1.45; 95% CI, 0.8 to 2.5) in favor of ABVD + INRT. For both F and U groups, noninferiority of ABVD only compared with combined modality treatment could not be demonstrated. Conclusion In stage I and II HL, PET response after two cycles of ABVD allows for early treatment adaptation. When ePET is positive after two cycles of ABVD, switching to BEACOPPesc + INRT significantly improved 5-year PFS. In ePET-negative patients, noninferiority of ABVD only could not be demonstrated: risk of relapse is increased when INRT is omitted, especially in patients in the F group.

Human peroxidasin 1 is a homotrimeric multidomain peroxidase that is secreted to the extracellular matrix. The heme enzyme was shown to release hypobromous acid that mediates the formation of specific covalent sulfilimine bonds to reinforce collagen IV in basement membranes. Maturation by proteolytic cleavage is known to activate the enzyme. Here, we present the first multimixing stopped-flow study on a fully functional truncated variant of human peroxidasin 1 comprising four immunoglobulin-like domains and the catalytically active peroxidase domain. The kinetic data unravel the so far unknown substrate specificity and mechanism of halide oxidation of human peroxidasin 1. The heme enzyme is shown to follow the halogenation cycle that is induced by the rapid H 2 O 2 -mediated oxidation of the ferric enzyme to the redox intermediate compound I. We demonstrate that chloride cannot act as a two-electron donor of compound I, whereas thiocyanate, iodide, and bromide efficiently restore the ferric resting state. We present all relevant apparent bimolecular rate constants, the spectral signatures of the redox intermediates, and the standard reduction potential of the Fe(III)/Fe(II) couple, and we demonstrate that the prosthetic heme group is post-translationally modified and cross-linked with the protein. These structural features provide the basis of human peroxidasin 1 to act as an effective generator of hypobromous acid, which mediates the formation of covalent cross-links in collagen IV., (© 2017 by The American Society for Biochemistry and Molecular Biology, Inc.)

Introduction: This article describes factors predicting James Cook University (JCU) medical graduates undertaking at least 1 year of remote practice. The cross-sectional design involved point-in-time (2015) analysis of the JCU medical school's ongoing longitudinal graduate tracking database. Participants were the first seven cohorts of graduates from the JCU medical school who had completed at least their postgraduate year (PGY) 4 in Australia ( n =529); that is, PGY 4 to PGY 10 graduates., Methods: Multiple logistic regression and Classification and Regression Tree (CART) analysis of medical graduate application data (age, gender, hometown, interview score, ethnicity), undergraduate data (scholarships awarded, clinical school location) and postgraduation data (internship location, specialty training) was performed. Analysis identified independent predictors of having practised for at least 1 year in a 'remote' Australian town (Australian Standard Geographic Classification Remoteness Area 4-5)., Results: Forty-seven (9%) of JCU Bachelor of Medicine and Bachelor of Surgery graduates in the first seven cohorts had practised for at least 1 year in a remote location between PGY 4 and 10. Practice in a 'remote' town was predicted by undertaking rural generalist training ( p <0.001; prevalence odds ratio (POR)=17.0), being awarded an 'above average' interview score at medical school selection ( p =0.006; POR=5.1), attending the Darwin clinical school in years 5-6 ( p =0.005; POR=4.7), being female ( p =0.016, POR=3.6) and undertaking an outer-regional or remotely based internship ( p =0.006; POR=3.5). CART analysis identified Indigenous graduates as another key subgroup of remote practice graduates., Conclusions: This study provides the first Australian evidence that likelihood of remote medical practice is enhanced by investment in a 'remote pipeline' - medical education via clinical schools and internships in rural/remote locations, with a later option of a rural generalist pathway. The proportion of medical graduates working in remote practice may also be increased by preferentially selecting Indigenous Australian applicants and applicants who score highly for communication, teamwork, self-reliance and motivation for rural and remote practice.

Background: Medication errors are the second most frequently reported hospital incident in Australia and are a global concern. A "Medication Calculation and Administration" workshop followed by a "hurdle" assessment (compulsory task mandating a minimum level of performance as a condition of passing the course) was introduced into Year 2 of the James Cook University medical curriculum to decrease dosage calculation and administration errors among graduates. This study evaluates the effectiveness of this educational activity as a long-term strategy to teach medical students' essential skills in calculating and administering medications., Methods: This longitudinal study used a pre- and post-test design to determine whether medical students retained their calculation and administration skills over a period of 4 years. The ability to apply basic mathematical skills to medication dose calculation, principles of safe administration (Part 1), and ability to access reference materials to check indications, contraindications, and writing the medication order with correct abbreviations (Part 2) were compared between Year 2 and 6 assessments., Results: Scores for Parts 1, 2 and total scores were nearly identical from Year 2 to Year 6 (P = 0.663, 0.408, and 0.472, respectively), indicating minimal loss of knowledge by students in this period. Most Year 6 students (86%) were able to recall at least 5 of the "6 Rights of Medication Administration" while 84% reported accessing reference material and 91% reported checking their medical calculations., Discussion: The "Medication Calculation and Administration" workshop with a combined formative and summative assessment - a "hurdle" - promotes long-term retention of essential clinical skills for medical students. These skills and an awareness of the problem are strategies to assist medical graduates in preventing future medication-related adverse events.

Survival rates for elderly Hodgkin Lymphoma (HL) have not improved substantially in recent years, mainly because of a lack of prospective randomized studies, due to difficulties in enrolling patients. Between 2002 and 2006, 54 untreated HL patients, aged between 65 and 80 years and considered 'non-frail' according to a comprehensive geriatric evaluation, were enrolled into a phase III randomized trial to compare a reduced-intensity regimen (vinblastine, cyclophosphamide, procarbazine, prednisone, etoposide, mitoxantrone, bleomycin; VEPEMB) with standard ABVD (adriamycin, bleomycin, vinblastine, dacarbazine). Primary endpoint was progression-free survival (PFS). Seventeen patients were in early stage (I-IIA), while 37 were advanced stage. Median age was 72 years and median follow-up was 76 months. Five-year PFS rates were 48% vs. 70% [adjusted Hazard ratio (HR) = 2·19, 95% confidence interval (CI) = 0·94-5·10, P = 0·068] and 5-year overall survival (OS) rates were 63% vs. 77% (adjusted HR = 1·67, 95% CI = 0·69-4·03, P = 0·254) for VEPEMB compared to ABVD. Overall treatment-related mortality was 4%. World Health Organization grade 4 cardiac and lung toxicity occurred in four patients treated with ABVD versus no cases in the VEPEMB arm. Standard ABVD regimen resulted in better PFS and OS than the VEPEMB, although the differences were not statistically significant. The low toxicity of both treatments was probably attributable to stringent selection of patients based on a Comprehensive Geriatric Assessment that excluded frail patients., (© 2016 John Wiley & Sons Ltd.)

Peripheral T cell lymphomas (PTCLs) are a heterogeneous group of lymphoid malignancies that portend a poor prognosis and have an undefined optimal therapeutic strategy. Data on best practices stem from prior studies that have generally included B cell lymphomas. However, the enhanced ability to diagnose PTCLs, the development of newer agents specific for PTCLs, and its increased incidence have called the scientific community to develop better strategies to combat these neoplasms. To that end, T cell lymphoma registries were developed in an attempt to answer relevant questions on the prognosis and management of PTCLs. The largest registries currently enrolling patients are the Comprehesive Oncology Measures for PeripheraL T-cEll Lymphoma TrEatment (COMPLETE) and the T-Cell Project. Despite the inherent limitations of these studies, valuable information are being collected to refine our management approaches and to aid in designing future clinical trials. This review illustrates the value of these registries and describes the critical questions that need to be answered.

We conducted a population-based study to establish the outcome of T-cell lymphoma (TCL) patients failing systemic first-line therapy. All TCL patients failing first-line systemic therapy in the province of Modena were identified from Modena Cancer Registry between 1997 and 2010. A total of 53 patients were analysed. Regarding the type of failure, 18 patients relapsed, and 35 progressed during first treatment. Among relapsed patients, the median time from date of response to relapse after first treatment was 6.2 months (range 1.87-102). A total of 18 patients (34%) died before receiving salvage treatment, 21 received platinum or gemcitabine-containing regimens (7 addressed to autologous stem cell transplant (ASCT)), 12 other CT regimens; 2 received radiotherapy (RT). The median survival after relapse (SAR) was 2.5 months. After a median follow-up for living patients after failure of 35 months (range 8-111 months), 44 patients died, and the cause of death was found to be lymphoma progression in all (98%) but one of them. The median SAR was 2.5 months. The 3-year SAR was 19%. Univariate and multivariate Cox regression analyses for SAR were performed. In multivariate analysis, performance status and type of failure were associated with a higher risk of death after relapse. The outcome of TCL patients failing first-line therapy is poor. Only a few cases that could receive ASCT had promising chances of long remission. There is urgent need for novel agents for patients requiring second-line treatment., (Copyright © 2014 John Wiley & Sons, Ltd.)

It is demonstrated that cyanobacteria (both azotrophic and non-azotrophic) contain heme b oxidoreductases that can convert chlorite to chloride and molecular oxygen (incorrectly denominated chlorite 'dismutase', Cld). Beside the water-splitting manganese complex of photosystem II, this metalloenzyme is the second known enzyme that catalyses the formation of a covalent oxygen-oxygen bond. All cyanobacterial Clds have a truncated N-terminus and are dimeric (i.e. clade 2) proteins. As model protein, Cld from Cyanothece sp. PCC7425 (CCld) was recombinantly produced in Escherichia coli and shown to efficiently degrade chlorite with an activity optimum at pH 5.0 [kcat 1144 ± 23.8 s(-1), KM 162 ± 10.0 μM, catalytic efficiency (7.1 ± 0.6) × 10(6) M(-1) s(-1)]. The resting ferric high-spin axially symmetric heme enzyme has a standard reduction potential of the Fe(III)/Fe(II) couple of -126 ± 1.9 mV at pH 7.0. Cyanide mediates the formation of a low-spin complex with k(on)  = (1.6 ± 0.1) × 10(5) M(-1) s(-1) and k(off) = 1.4 ± 2.9 s(-1) (KD ∼ 8.6 μM). Both, thermal and chemical unfolding follows a non-two-state unfolding pathway with the first transition being related to the release of the prosthetic group. The obtained data are discussed with respect to known structure-function relationships of Clds. We ask for the physiological substrate and putative function of these O2 -producing proteins in (nitrogen-fixing) cyanobacteria., (© 2015 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.)

Human peroxidasin 1 (hsPxd01) is a multidomain heme peroxidase that uses bromide as a cofactor for the formation of sulfilimine cross-links. The latter confers critical structural reinforcement to collagen IV scaffolds. Here, hsPxd01 and various truncated variants lacking nonenzymatic domains were recombinantly expressed in HEK cell lines. The N-glycosylation site occupancy and disulfide pattern, the oligomeric structure, and unfolding pathway are reported. The homotrimeric iron protein contains a covalently bound ferric high spin heme per subunit with a standard reduction potential of the Fe(III)/Fe(II) couple of -233 ± 5 mV at pH 7.0. Despite sequence homology at the active site and biophysical properties similar to human peroxidases, the catalytic efficiency of bromide oxidation (kcat/KM(app)) of full-length hsPxd01 is rather low but increased upon truncation. This is discussed with respect to its structure and proposed biosynthetic function in collagen IV cross-linking., (© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.)

Purpose: Combined-modality treatment is standard treatment for patients with clinical stage I/II Hodgkin lymphoma (HL). We hypothesized that an early positron emission tomography (PET) scan could be used to adapt treatment. Therefore, we started the randomized EORTC/LYSA/FIL Intergroup H10 trial evaluating whether involved-node radiotherapy (IN-RT) could be omitted without compromising progression-free survival in patients attaining a negative early PET scan after two cycles of ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) as compared with standard combined-modality treatment., Patients and Methods: Patients age 15 to 70 years with untreated clinical stage I/II HL were eligible. Here we report the clinical outcome of the preplanned interim futility analysis scheduled to occur after documentation of 34 events in the early PET-negative group. Because testing for futility in this noninferiority trial corresponds to testing the hypothesis of no difference, a one-sided superiority test was conducted., Results: The analysis included 1,137 patients. In the favorable subgroup, 85.8% had a negative early PET scan (standard arm, one event v experimental arm, nine events). In the unfavorable subgroup, 74.8% had a negative early PET scan (standard arm, seven events v experimental arm, 16 events). The independent data monitoring committee concluded it was unlikely that we would show noninferiority in the final results for the experimental arm and advised stopping random assignment for early PET-negative patients., Conclusion: On the basis of this analysis, combined-modality treatment resulted in fewer early progressions in clinical stage I/II HL, although early outcome was excellent in both arms. The final analysis will reveal whether this finding is maintained over time.

Chlorite dismutases (Clds) are heme b containing oxidoreductases that convert chlorite to chloride and molecular oxygen. In order to elucidate the role of conserved heme cavity residues in the catalysis of this reaction comprehensive mutational and biochemical analyses of Cld from "Candidatus Nitrospira defluvii" (NdCld) were performed. Particularly, point mutations of the cavity-forming residues R173, K141, W145, W146, and E210 were performed. The effect of manipulation in 12 single and double mutants was probed by UV-vis spectroscopy, spectroelectrochemistry, pre-steady-state and steady-state kinetics, and X-ray crystallography. Resulting biochemical data are discussed with respect to the known crystal structure of wild-type NdCld and the variants R173A and R173K as well as the structures of R173E, W145V, W145F, and the R173Q/W146Y solved in this work. The findings allow a critical analysis of the role of these heme cavity residues in the reaction mechanism of chlorite degradation that is proposed to involve hypohalous acid as transient intermediate and formation of an O═O bond. The distal R173 is shown to be important (but not fully essential) for the reaction with chlorite, and, upon addition of cyanide, it acts as a proton acceptor in the formation of the resulting low-spin complex. The proximal H-bonding network including K141-E210-H160 keeps the enzyme in its ferric (E°' = -113 mV) and mainly five-coordinated high-spin state and is very susceptible to perturbation.

Reconstructing the phylogenetic relationships of the main evolutionary lines of the mammalian peroxidases lactoperoxidase and myeloperoxidase revealed the presence of novel bacterial heme peroxidase subfamilies. Here, for the first time, an ancestral bacterial heme peroxidase is shown to possess a very high bromide oxidation activity (besides conventional peroxidase activity). The recombinant protein allowed monitoring of the autocatalytic peroxide-driven formation of covalent heme to protein bonds. Thereby, the high spin ferric rhombic heme spectrum became similar to lactoperoxidase, the standard reduction potential of the Fe(III)/Fe(II) couple shifted to more positive values (-145 ± 10 mV at pH 7), and the conformational and thermal stability of the protein increased significantly. We discuss structure-function relationships of this new peroxidase in relation to its mammalian counterparts and ask for its putative physiological role.

Purpose: The differential diagnosis among the commonest peripheral T-cell lymphomas (PTCLs; ie, PTCL not otherwise specified [NOS], angioimmunoblastic T-cell lymphoma [AITL], and anaplastic large-cell lymphoma [ALCL]) is difficult, with the morphologic and phenotypic features largely overlapping. We performed a phase III diagnostic accuracy study to test the ability of gene expression profiles (GEPs; index test) to identify PTCL subtype., Methods: We studied 244 PTCLs, including 158 PTCLs NOS, 63 AITLs, and 23 ALK-negative ALCLs. The GEP-based classification method was established on a support vector machine algorithm, and the reference standard was an expert pathologic diagnosis according to WHO classification., Results: First, we identified molecular signatures (molecular classifier [MC]) discriminating either AITL and ALK-negative ALCL from PTCL NOS in a training set. Of note, the MC was developed in formalin-fixed paraffin-embedded (FFPE) samples and validated in both FFPE and frozen tissues. Second, we found that the overall accuracy of the MC was remarkable: 98% to 77% for AITL and 98% to 93% for ALK-negative ALCL in test and validation sets of patient cases, respectively. Furthermore, we found that the MC significantly improved the prognostic stratification of patients with PTCL. Particularly, it enhanced the distinction of ALK-negative ALCL from PTCL NOS, especially from some CD30+ PTCL NOS with uncertain morphology. Finally, MC discriminated some T-follicular helper (Tfh) PTCL NOS from AITL, providing further evidence that a group of PTCLs NOS shares a Tfh derivation with but is distinct from AITL., Conclusion: Our findings support the usage of an MC as additional tool in the diagnostic workup of nodal PTCL.

Purpose: The International Peripheral T-Cell Lymphoma Project was undertaken to better understand the subtypes of T-cell and natural killer (NK) -cell lymphomas., Patients and Methods: Angioimmunoblastic T-cell lymphoma (AITL) was diagnosed according to the 2001 WHO criteria by a central review process consisting of panels of expert hematopathologists. Clinical, pathologic, immunophenotyping, treatment, and survival data were correlated., Results: Of 1,314 patients, 243 (18.5%) were diagnosed with AITL. At presentation, generalized lymphadenopathy was noted in 76% of patients, and 89% had stages III to IV disease. Skin rash was observed in 21% of patients. Hemolytic anemia and hypergammoglobulinemia occurred in 13% and 30% of patients, respectively. Five-year overall and failure-free survivals were 33% and 18%, respectively. At presentation, prognostic models were evaluated, including the standard International Prognostic Index, which comprised the following factors: age ≥ 60 years, stages III to IV disease, lactic dehydrogenase (LDH) > normal, extranodal sites (ENSs) > one, and performance status (PS) ≥ 2; the Prognostic Index for Peripheral T-Cell Lymphoma, comprising: age ≥ 60 years, PS ≥ 2, LDH > normal, and bone marrow involvement; and the alternative Prognostic Index for AITL (PIAI), comprising: age > 60 years, PS ≥ 2, ENSs > one, B symptoms, and platelet count < 150 × 10(9)/L. The simplified PIAI had a low-risk group (zero to one factors), with 5-year survival of 44%, and a high-risk group (two to five factors), with 5-year survival of 24% (P = .0065)., Conclusion: AITL is a rare clinicopathologic entity characterized by an aggressive course and dismal outcome with current therapies.

Chlorite dismutases (Clds) are heme b-containing oxidoreductases that convert chlorite to chloride and dioxygen. In this work, the thermodynamics of the one-electron reduction of the ferric high-spin forms and of the six-coordinate low-spin cyanide adducts of the enzymes from Nitrobacter winogradskyi (NwCld) and Candidatus "Nitrospira defluvii" (NdCld) were determined through spectroelectrochemical experiments. These proteins belong to two phylogenetically separated lineages that differ in subunit (21.5 and 26 kDa, respectively) and oligomeric (dimeric and pentameric, respectively) structure but exhibit similar chlorite degradation activity. The E°' values for free and cyanide-bound proteins were determined to be -119 and -397 mV for NwCld and -113 and -404 mV for NdCld, respectively (pH 7.0, 25 °C). Variable-temperature spectroelectrochemical experiments revealed that the oxidized state of both proteins is enthalpically stabilized. Molecular dynamics simulations suggest that changes in the protein structure are negligible, whereas solvent reorganization is mainly responsible for the increase in entropy during the redox reaction. Obtained data are discussed with respect to the known structures of the two Clds and the proposed reaction mechanism.

Purpose: Patients with follicular lymphoma (FL) registered in the F2-study and initially managed without treatment were analyzed to describe the presentation and outcome of a watch and wait (W&W) strategy in the rituximab era, to identify parameters for initiating treatment, and to evaluate whether initial W&W could have deleterious effects on treatment efficacy after progression or relapse., Patients and Methods: Between 2003 and 2005, 120 patients selected from the 1,093 treatment-naive patients with FL in the F2-study cohort were initially managed expectantly (W&W), and 107 patients were assessed. Most of these patients (80%) had disseminated disease with a low tumor burden according to Groupe d'Etudes des Lymphomes Folliculaires criteria., Results: After a median follow-up of 64 months, treatment was initiated in 54 patients (50%), with a median delay of 55 months for the entire cohort. In a univariate analysis, involvement of more than four nodal areas (hazard ratio [HR], 2.26) and serum albumin less than 3.5 g/dL (HR, 3.51) were predictive of a shorter time to lymphoma treatment initiation. In a multivariate analysis, only involvement of more than four nodal areas remained significant (HR, 2.32). The 4-year freedom from treatment failure (FFTF) rate of W&W patients (79%; 95% CI, 69% to 85%) was not inferior to that of a subgroup of 242 patients from the F2-study cohort with good prognosis characteristics who were initially treated with a rituximab-based regimen (69%; 95% CI, 61% to 76%; P = .103)., Conclusion: In the rituximab era, patients with FL in a selected prognostically favorable group can still be managed with W&W. W&W does not seem to have detrimental effects on FFTF and overall survival rates after treatment.

The low-pH conformational equilibria of ferric yeast iso-1 cytochrome c (ycc) and its M80A, M80A/Y67H, and M80A/Y67A variants were studied from pH 7 to 2 at low ionic strength through electronic absorption, magnetic circular dichroism, and resonance Raman spectroscopies. For wild-type ycc, the protein structure, axial heme ligands, and spin state of the iron atom convert from the native folded His/Met low-spin (LS) form to a molten globule His/H(2)O high-spin (HS) form and a totally unfolded bis-aquo HS state, in a single cooperative transition with an apparent pK(a) of ~3.0. An analogous cooperative transition occurs for the M80A and M80A/Y67H variants. This is preceded by protonation of heme propionate-7, with a pK(a) of ~4.2, and by an equilibrium between a His/OH(-)-ligated LS and a His/H(2)O-ligated HS conformer, with a pK(a) of ~5.9. In the M80A/Y67A variant, the cooperative low-pH transition is split into two distinct processes because of an increased stability of the molten globule state that is formed at higher pH values than the other species. These data show that removal of the axial methionine ligand does not significantly alter the mechanism of acidic unfolding and the ranges of stability of low-pH conformers. Instead, removal of a hydrogen bonding partner at position 67 increases the stability of the molten globule and renders cytochrome c more susceptible to acid unfolding. This underlines the key role played by Tyr67 in stabilizing the three-dimensional structure of cytochrome c by means of the hydrogen bonding network connecting the Ω loops formed by residues 71-85 and 40-57.

All phytopathogenic fungi have two catalase-peroxidase paralogues located either intracellularly (KatG1) or extracellularly (KatG2). Here, for the first time a secreted bifunctional, homodimeric catalase-peroxidase (KatG2 from the rice blast fungus Magnaporthe grisea) has been produced heterologously with almost 100% heme occupancy and comprehensively investigated by using a broad set of methods including UV-Vis, ECD and resonance Raman spectroscopy (RR), thin-layer spectroelectrochemistry, mass spectrometry, steady-state & presteady-state spectroscopy. RR spectroscopy reveals that MagKatG2 shows a unique mixed-spin state, non-planar heme b, and a proximal histidine with pronounced imidazolate character. At pH 7.0 and 25 °C, the standard reduction potential E°' of the Fe(III)/Fe(II) couple for the high-spin native protein was found to fall in the range typical for the KatG family. Binding of cyanide was relatively slow at pH 7.0 and 25 °C and with a K(d) value significantly higher than for the intracellular counterpart. Demonstrated by mass spectrometry MagKatG2 has the typical Trp118-Tyr251-Met277 adduct that is essential for its predominantly catalase activity at the unique acidic pH optimum. In addition, MagKatG2 acts as a versatile peroxidase using both one- and two-electron donors. Based on these data, structure-function relationships of extracellular eukaryotic KatGs are discussed with respect to intracellular KatGs and possible role(s) in host-pathogen interaction., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Peripheral T-cell lymphomas are a group of rare neoplasms originating from clonal proliferation of mature post-thymic lymphocytes with different entities having specific biological characteristics and clinical features. As natural killer cells are closely related to T-cells, natural killer-cell lymphomas are also part of the group. The current World Health Organization classification recognizes four categories of T/natural killer-cell lymphomas with respect to their presentation: disseminated (leukemic), nodal, extranodal and cutaneous. Geographic variations in the distribution of these diseases are well documented: nodal subtypes are more frequent in Europe and North America, while extranodal forms, including natural killer-cell lymphomas, occur almost exclusively in Asia and South America. On the whole, T-cell lymphomas are more common in Asia than in western countries, usually affect adults, with a higher tendency in men, and, excluding a few subtypes, usually have an aggressive course and poor prognosis. Apart from anaplastic lymphoma kinase-positive anaplastic large cell lymphoma, that have a good outcome, other nodal and extranodal forms have a 5-year overall survival of about 30%. According to the principal prognostic indexes, the majority of patients are allocated to the unfavorable subset. In the past, the rarity of these diseases prevented progress in the understanding of their biology and improvements in the efficaciousness of therapy. Recently, international projects devoted to these diseases created networks promoting investigations on T-cell lymphomas. These projects are the basis of forthcoming cooperative, large scale trials to detail biologic characteristics of each sub-entity and to possibly individuate targets for new therapies.

Follicular lymphoma is the second most frequent non-Hodgkin lymphoma accounting for about 10-20% of all lymphomas in western countries. The median age at diagnosis is 60 years old. The clinical presentation is usually characterized by asymptomatic peripheral adenopathy in cervical, axillary, inguinal and femoral regions. Treatment options for patients with naïve or recurrent follicular lymphoma are still controversial, ranging from a "watch and wait" policy to hematopoietic stem cell transplantation. More recently, the availability of rituximab has substantially changed follicular lymphoma therapeutic approaches to such an extent that R-Chemo is now the standard induction first-line treatment. This review provides a general overview of the state of the art in the management of follicular lymphoma and also, a brief description regarding the current prognostic tools available for treatment decisions.

In mammalian peroxidases the proximal histidine is in close interaction with a fully conserved asparagine which in turn is hydrogen bonded with an arginine that stabilizes the propionate substituent of pyrrol ring D in bent conformation. In order to probe the role of this rigid proximal architecture for structural integrity and catalysis of human myeloperoxidase (MPO), the variants Asn421Asp, Arg333Ala and Arg333Lys have been recombinantly expressed in HEK cell lines. The standard reduction potential of the Fe(III)/Fe(II) couple of Asn421Asp was still wild-type-like (-50mV at pH 7.0) but the spectral properties of the ferric and ferrous forms as well as of higher oxidation states showed significant differences. Additionally, rates of ligand binding and oxidation of both one- and two-electron donors were diminished. The effect of exchange of Arg333 was even more dramatic. We did not succeed in production of mutant proteins that could bind heme at the active site. The importance of this His-Asn-Arg triad in linking the heme iron with the propionate at pyrrol ring D for heme insertion and binding as well as in maintenance of the architecture of the substrate binding site(s) at the entrance to the heme cavity is discussed., (Copyright © 2011 Elsevier Inc. All rights reserved.)