COVID-19 Outcomes in Patients with Hematologic Malignancies in the Era of COVID-19 Vaccination and the Omicron Variant.

A greater understanding of clinical trends in COVID-19 outcomes among patients with hematologic malignancies (HM) over the course of the pandemic, particularly the Omicron era, is needed. This ongoing, observational, and registry-based study with prospective data collection evaluated COVID-19 clinical severity and mortality in 1818 adult HM patients diagnosed with COVID-19 between 27 February 2020 and 1 October 2022, at 31 centers in the Madrid region of Spain. Of these, 1281 (70.5%) and 537 (29.5%) were reported in the pre-Omicron and Omicron periods, respectively. Overall, patients aged ≥70 years (odds ratio 2.16, 95% CI 1.64-2.87), with >1 comorbidity (2.44, 1.85-3.21), or with an underlying HM of chronic lymphocytic leukemia (1.64, 1.19-2.27), had greater odds of severe/critical COVID-19; odds were lower during the Omicron BA.1/BA.2 (0.28, 0.2-0.37) or BA.4/BA.5 (0.13, 0.08-0.19) periods and among patients vaccinated with one or two (0.51, 0.34-0.75) or three or four (0.22, 0.16-0.29) doses. The hospitalization rate (75.3% [963/1279], 35.7% [191/535]), rate of intensive care admission (30.0% [289/963], 14.7% [28/191]), and mortality rate overall (31.9% [409/1281], 9.9% [53/536]) and in hospitalized patients (41.3% [398/963], 22.0% [42/191]) decreased from the pre-Omicron to Omicron period. Age ≥70 years was the only factor associated with higher mortality risk in both the pre-Omicron (hazard ratio 2.57, 95% CI 2.03-3.25) and Omicron (3.19, 95% CI 1.59-6.42) periods. Receipt of prior stem cell transplantation, COVID-19 vaccination(s), and treatment with nirmatrelvir/ritonavir or remdesivir were associated with greater survival rates. In conclusion, COVID-19 mortality in HM patients has decreased considerably in the Omicron period; however, mortality in hospitalized HM patients remains high. Specific studies should be undertaken to test new treatments and preventive interventions in HM patients.

Establishment of a Latin American dataset to enable the construction of gestational weight gain charts for adolescents.

Gestational weight gain is an important indicator for monitoring nutritional status during pregnancy. However, there are no gestational weight gain references created for adolescents or national datasets to enable the construction of such graphs up to date. This manuscript aims to describe the creation of a Latin American dataset to construct gestational weight gain references for adolescents aged 10-19 years old. Gestational weight gain data from studies conducted in nine countries (Argentina, Brazil, Chile, Colombia, Mexico, Panama, Paraguay, Peru, and Uruguay) collected between 2003 and 2021 were harmonized. Data on height, weight, and gestational age in at least two gestational trimesters were included. Pregnant adolescents should be free of diseases that could affect weight, and newborns should weigh between 2,500-4,000 g and be free of congenital malformations. The final dataset included 6,414 individuals after data cleaning. Heterogeneity between the countries was assessed by calculating standardized site differences for GWG and z scores of height-for-age. Several imputation procedures were tested, and approximately 10% of the first-trimester weights were imputed. The prevalence of individuals with underweight (1.5%) and obesity (5.3%) was low, which may lead to problems when modeling the curves for such BMI categories. Maternal height and gestational weight gain did not show significant differences by country, according to the standardized site differences. A harmonized dataset of nine countries with imputed data in the first trimester of pregnancy was prepared to construct Latin American gestational weight gain curves for adolescents.

Gestational weight gain charts for Latin American adolescents.

Monitoring gestational weight gain (GWG) throughout pregnancy among adolescents is important for detecting individuals at risk and timely intervention. However, there are no specific tools or guidelines for GWG monitoring of this group. We aimed to construct GWG charts for pregnant adolescents (10-19 years old) according to pre-pregnancy body mass index (BMI) using a pooled dataset from nine Latin American countries. Datasets from Argentina, Brazil, Chile, Colombia, Mexico, Panama, Paraguay, Peru, and Uruguay collected between 2003 and 2021 were combined after data cleaning and harmonization. Adolescents free of diseases that could affect GWG and who gave birth to newborns weighing between 2,500-4,000 g and free of congenital malformations were included. Multiple imputation techniques were applied to increase the sample size available for underweight and obesity categories. Generalized Additive Models for Location, Scale, and Shape were used to construct the charts of GWG according to gestational age. Internal and external validation procedures were performed to ensure that models were not over-adjusted to the data. The cohort included 6,414 individuals and 29,414 measurements to construct the charts and 1,684 individuals and 8,879 measurements for external validation. The medians (and interquartile ranges) for GWG at 40 weeks according to pre-pregnancy BMI were: underweight, 14.9 (11.9-18.6); normal weight, 14.0 (10.6-17.7); overweight, 11.6 (7.7-15.6); obesity, 10.6 kg (6.7-14.3). Internal and external validation showed that the percentages above/below selected percentiles were close to those expected, except for underweight adolescents. These charts describe the GWG throughout pregnancy among Latin American adolescents and represent a significant contribution to the prenatal care of this group. GWG cut-offs based on values associated with lower risks of unfavorable outcomes for the mother-child binomial should be determined before implementing the charts in clinical practice.

Solution Structure of Poly(UG) RNA.

Poly(UG) or "pUG" RNAs are UG or GU dinucleotide repeat sequences which are highly abundant in eukaryotes. Post-transcriptional addition of pUGs to RNA 3' ends marks mRNAs as vectors for gene silencing in C. elegans. We previously determined the crystal structure of pUG RNA bound to the ligand N-methyl mesoporphyrin IX (NMM), but the structure of free pUG RNA is unknown. Here we report the solution structure of the free pUG RNA (GU)12, as determined by nuclear magnetic resonance spectroscopy and small and wide-angle x-ray scattering (NMR-SAXS-WAXS). The low complexity sequence and 4-fold symmetry of the structure result in overlapped NMR signals that complicate chemical shift assignment. We therefore utilized single site-specific deoxyribose modifications which did not perturb the structure and introduced well-resolved methylene signals that are easily identified in NMR spectra. The solution structure ensemble has a root mean squared deviation (RMSD) of 0.62 Å and is a compact, left-handed quadruplex with a Z-form backbone, or "pUG fold." Overall, the structure agrees with the crystal structure of (GU)12 bound to NMM, indicating the pUG fold is unaltered by docking of the NMM ligand. The solution structure reveals conformational details that could not be resolved by x-ray crystallography, which explain how the pUG fold can form within longer RNAs.

An Arg/Ala-rich helix in the N-terminal region of M. tuberculosis FtsQ is a potential membrane anchor of the Z-ring.

Mtb infects a quarter of the worldwide population. Most drugs for treating tuberculosis target cell growth and division. With rising drug resistance, it becomes ever more urgent to better understand Mtb cell division. This process begins with the formation of the Z-ring via polymerization of FtsZ and anchoring of the Z-ring to the inner membrane. Here we show that the transmembrane protein FtsQ is a potential membrane anchor of the Mtb Z-ring. In the otherwise disordered cytoplasmic region of FtsQ, a 29-residue, Arg/Ala-rich α-helix is formed that interacts with upstream acidic residues in solution and with acidic lipids at the membrane surface. This helix also binds to the GTPase domain of FtsZ, with implications for drug binding and Z-ring formation.

COVID-19 Severity and Survival over Time in Patients with Hematologic Malignancies: A Population-Based Registry Study.

Mortality rates for COVID-19 have declined over time in the general population, but data in patients with hematologic malignancies are contradictory. We identified independent prognostic factors for COVID-19 severity and survival in unvaccinated patients with hematologic malignancies, compared mortality rates over time and versus non-cancer inpatients, and investigated post COVID-19 condition. Data were analyzed from 1166 consecutive, eligible patients with hematologic malignancies from the population-based HEMATO-MADRID registry, Spain, with COVID-19 prior to vaccination roll-out, stratified into early (February-June 2020; n = 769 (66%)) and later (July 2020-February 2021; n = 397 (34%)) cohorts. Propensity-score matched non-cancer patients were identified from the SEMI-COVID registry. A lower proportion of patients were hospitalized in the later waves (54.2%) compared to the earlier (88.6%), OR 0.15, 95%CI 0.11-0.20. The proportion of hospitalized patients admitted to the ICU was higher in the later cohort (103/215, 47.9%) compared with the early cohort (170/681, 25.0%, 2.77; 2.01-3.82). The reduced 30-day mortality between early and later cohorts of non-cancer inpatients (29.6% vs. 12.6%, OR 0.34; 0.22-0.53) was not paralleled in inpatients with hematologic malignancies (32.3% vs. 34.8%, OR 1.12; 0.81-1.5). Among evaluable patients, 27.3% had post COVID-19 condition. These findings will help inform evidence-based preventive and therapeutic strategies for patients with hematologic malignancies and COVID-19 diagnosis.

An atypical RNA quadruplex marks RNAs as vectors for gene silencing.

The addition of poly(UG) ('pUG') repeats to 3' termini of mRNAs drives gene silencing and transgenerational epigenetic inheritance in the metazoan Caenorhabditis elegans. pUG tails promote silencing by recruiting an RNA-dependent RNA polymerase (RdRP) that synthesizes small interfering RNAs. Here we show that active pUG tails require a minimum of 11.5 repeats and adopt a quadruplex (G4) structure we term the pUG fold. The pUG fold differs from known G4s in that it has a left-handed backbone similar to Z-RNA, no consecutive guanosines in its sequence, and three G quartets and one U quartet stacked non-sequentially. The compact pUG fold binds six potassium ions and brings the RNA ends into close proximity. The biological importance of the pUG fold is emphasized by our observations that porphyrin molecules bind to the pUG fold and inhibit both gene silencing and binding of RdRP. Moreover, specific 7-deaza substitutions that disrupt the pUG fold neither bind RdRP nor induce RNA silencing. These data define the pUG fold as a previously unrecognized RNA structural motif that drives gene silencing. The pUG fold can also form internally within larger RNA molecules. Approximately 20,000 pUG-fold sequences are found in noncoding regions of human RNAs, suggesting that the fold probably has biological roles beyond gene silencing.

A Surface Exposed, Two-Domain Lipoprotein Cargo of a Type XI Secretion System Promotes Colonization of Host Intestinal Epithelia Expressing Glycans.

The only known required component of the newly described Type XI secretion system (TXISS) is an outer membrane protein (OMP) of the DUF560 family. TXISSOMPs are broadly distributed across proteobacteria, but properties of the cargo proteins they secrete are largely unexplored. We report biophysical, histochemical, and phenotypic evidence that Xenorhabdus nematophila NilC is surface exposed. Biophysical data and structure predictions indicate that NilC is a two-domain protein with a C-terminal, 8-stranded ß-barrel. This structure has been noted as a common feature of TXISS effectors and may be important for interactions with the TXISSOMP. The NilC N-terminal domain is more enigmatic, but our results indicate it is ordered and forms a ß-sheet structure, and bioinformatics suggest structural similarities to carbohydrate-binding proteins. X. nematophila NilC and its presumptive TXISSOMP partner NilB are required for colonizing the anterior intestine of Steinernema carpocapsae nematodes: the receptacle of free-living, infective juveniles and the anterior intestinal cecum (AIC) in juveniles and adults. We show that, in adult nematodes, the AIC expresses a Wheat Germ Agglutinin (WGA)-reactive material, indicating the presence of N-acetylglucosamine or N-acetylneuraminic acid sugars on the AIC surface. A role for this material in colonization is supported by the fact that exogenous addition of WGA can inhibit AIC colonization by X. nematophila. Conversely, the addition of exogenous purified NilC increases the frequency with which X. nematophila is observed at the AIC, demonstrating that abundant extracellular NilC can enhance colonization. NilC may facilitate X. nematophila adherence to the nematode intestinal surface by binding to host glycans, it might support X. nematophila nutrition by cleaving sugars from the host surface, or it might help protect X. nematophila from nematode host immunity. Proteomic and metabolomic analyses of wild type X. nematophila compared to those lacking nilB and nilC revealed differences in cell wall and secreted polysaccharide metabolic pathways. Additionally, purified NilC is capable of binding peptidoglycan, suggesting that periplasmic NilC may interact with the bacterial cell wall. Overall, these findings support a model that NilB-regulated surface exposure of NilC mediates interactions between X. nematophila and host surface glycans during colonization. This is a previously unknown function for a TXISS.

Concordancia entre pruebas de estabilidad unipodal estática para riesgo de caída en adultos mayores chilenos / Concordance between Static Unipodal Stability Tests concerning Risk of Falling in Chilean Aged Adults

Introducción: El equilibrio postural conforma parte de la evaluación funcional para riesgo de caída en adultos mayores. El Ministerio de Salud Chileno aplica el Test Estación Unipodal para valora la estabilidad unipodal estática como herramienta de prevención en salud. Objetivo: Determinar la concordancia o equivalencia diagnóstica entre el Test Estación Unipodal y el Test unipodal para estabilidad corporal estática, en modalidad ojos abiertos. Métodos: Estudio de concordancia diagnóstica, de tipo transversal; aplicado en 60 adultos mayores autovalentes pertenecientes a talleres deportivos del Gimnasio Olímpico de San Miguel, Región Metropolitana, Chile, quienes voluntariamente ejecutaron dos pruebas de estabilidad unipodal estática y respondieron un instrumento de consulta al final de la evaluación referida al Test unipodal para estabilidad corporal estática. Resultados: Entre las dos pruebas de estabilidad unipodal, en modalidad ojos abiertos, se presentó una concordancia significativa al evaluar buena o deficiente estabilidad (p = 0,0005). Los adultos mayores evaluados percibieron el Test unipodal para estabilidad corporal estática como prueba de fácil aplicación, bajo nivel de riesgo físico y cansancio, declarando intención de volver a realizarla si se requiere valorar nuevamente su estabilidad. Conclusión: Ambos métodos, Test Estación Unipodal y Test unipodal para estabilidad corporal estática, en modalidad ojos abiertos, fueron capaces de clasificar correctamente buena estabilidad o estabilidad deficiente en los adultos mayores evaluados. Por lo tanto, resultan equivalentes y concordantes para el diagnóstico de la estabilidad estática con apoyo unipodal(AU)

Introduction: Postural balance is part of the functional assessment for risk of falling in aged adults. The Chilean Ministry of Health applies the Unipodal Station Test to assess static unipodal stability as a health prevention tool. Objective: To determine concordance or diagnostic equivalence between the Unipodal Station Test and the Unipodal Test for static body stability, in the open eyes modality. Methods: Cross-sectional study of diagnostic concordance applied in sixty self-supporting aged adults belonging to sports workshops of the Olympic Gymnasium of San Miguel, in the Metropolitan Region of Chile, who voluntarily completed two static unipodal stability tests and answered a consultation instrument at the end of the assessment concerning the Unipodal Test for static body stability. Results: Between the two unipodal stability tests, in the open eyes modality, a significant concordance was present upon assessing good or poor stability (p = 0.0005). The aged adults who underwent assessment perceived the Unipodal Test for static body stability as a test of easy application and low level of physical risk and fatigue, as well as declared their intention to complete it again if their stability needed to be reassessed. Conclusion: Both the Unipodal Station Test and the Unipodal Test for static body stability, in the open eyes modality, were effective methods to classify good stability or poor stability correctly in the aged adults who underwent assessment. Therefore, they are equivalent and concordant for the diagnosis of static stability with unipodal support(AU)

Characteristics, clinical outcomes, and risk factors of SARS-COV-2 infection in adult acute myeloid leukemia patients: experience of the PETHEMA group.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection produces higher morbidity and mortality in hematological malignancies, but evidence in acute myeloid leukemia (AML) is scarce. A multicenter observational study was conducted to determine the clinical outcomes and assess the impact of therapeutic approaches in adult AML patients with SARS-CoV-2 infection in the first wave (March-May 2020). Overall, 108 patients were included: 51.9% with active leukemia and 70.4% under therapeutic schedules for AML. Signs and symptoms of SARS-CoV-2 were present in 96.3% of patients and 82.4% received specific treatment for SARS-CoV-2. The mortality rate was 43.5% and was correlated with age, gender, active leukemia, dyspnea, severe SARS-CoV-2, intensive care measures, neutrophil count, and D-dimer levels. A protective effect was found with azithromycin, lopinavir/ritonavir, and normal liver enzyme levels. During the SARS-CoV-2 first wave, our findings suggested an increased mortality in AML in a short period. SARS-CoV-2 management could be guided by risk factors in AML patients.

Structural interactions define assembly adapter function of a type II secretion system pseudopilin.

The type IV filament superfamily comprises widespread membrane-associated polymers in prokaryotes. The type II secretion system (T2SS), a virulence pathway in many pathogens, belongs to this superfamily. A knowledge gap in understanding of the T2SS is the molecular role of a small "pseudopilin" protein. Using multiple biophysical techniques, we have deciphered how this missing component of the Xcp T2SS architecture is structurally integrated, and thereby unlocked its function. We demonstrate that low-abundance XcpH is the adapter that bridges a trimeric initiating tip complex, XcpIJK, with a periplasmic filament of XcpG subunits. Each pseudopilin protein caps an XcpG protofilament in an overall pseudopilus compatible with dimensions of the periplasm and the outer membrane-spanning secretin through which substrates pass. Unexpectedly, to fulfill its adapter function, the XcpH N-terminal helix must be unwound, a property shared with XcpG subunits. We provide an experimentally validated three-dimensional structural model of a complete type IV filament.

Fuzzy Association of an Intrinsically Disordered Protein with Acidic Membranes.

Many physiological and pathophysiological processes, including Mycobacterium tuberculosis (Mtb) cell division, may involve fuzzy membrane association by proteins via intrinsically disordered regions. The fuzziness is extreme when the conformation and pose of the bound protein and the composition of the proximal lipids are all highly dynamic. Here, we tackled the challenge in characterizing the extreme fuzzy membrane association of the disordered, cytoplasmic N-terminal region (NT) of ChiZ, an Mtb divisome protein, by combining solution and solid-state NMR spectroscopy and molecular dynamics simulations. While membrane-associated NT does not gain any secondary structure, its interactions with lipids are not random, but formed largely by Arg residues predominantly in the second, conserved half of the NT sequence. As NT frolics on the membrane, lipids quickly redistribute, with acidic lipids, relative to zwitterionic lipids, preferentially taking up Arg-proximal positions. The asymmetric engagement of NT arises partly from competition between acidic lipids and acidic residues, all in the first half of NT, for Arg interactions. This asymmetry is accentuated by membrane insertion of the downstream transmembrane helix. This type of semispecific molecular recognition may be a general mechanism by which disordered proteins target membranes.

Impact of hematologic malignancy and type of cancer therapy on COVID-19 severity and mortality: lessons from a large population-based registry study.

BACKGROUND: Patients with cancer have been shown to have a higher risk of clinical severity and mortality compared to non-cancer patients with COVID-19. Patients with hematologic malignancies typically are known to have higher levels of immunosuppression and may develop more severe respiratory viral infections than patients with solid tumors. Data on COVID-19 in patients with hematologic malignancies are limited. Here we characterize disease severity and mortality and evaluate potential prognostic factors for mortality. METHODS: In this population-based registry study, we collected de-identified data on clinical characteristics, treatment and outcomes in adult patients with hematologic malignancies and confirmed severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection within the Madrid region of Spain. Our case series included all patients admitted to 22 regional health service hospitals and 5 private healthcare centers between February 28 and May 25, 2020. The primary study outcome was all-cause mortality. We assessed the association between mortality and potential prognostic factors using Cox regression analyses adjusted for age, sex, comorbidities, hematologic malignancy and recent active cancer therapy. RESULTS: Of 833 patients reported, 697 were included in the analyses. Median age was 72 years (IQR 60-79), 413 (60%) patients were male and 479 (69%) and 218 (31%) had lymphoid and myeloid malignancies, respectively. Clinical severity of COVID-19 was severe/critical in 429 (62%) patients. At data cutoff, 230 (33%) patients had died. Age ≥ 60 years (hazard ratios 3.17-10.1 vs < 50 years), > 2 comorbidities (1.41 vs ≤ 2), acute myeloid leukemia (2.22 vs non-Hodgkin lymphoma) and active antineoplastic treatment with monoclonal antibodies (2·02) were associated with increased mortality; conventional chemotherapy showed borderline significance (1.50 vs no active therapy). Conversely, Ph-negative myeloproliferative neoplasms (0.33) and active treatment with hypomethylating agents (0.47) were associated with lower mortality. Overall, 574 (82%) patients received antiviral therapy. Mortality with severe/critical COVID-19 was higher with no therapy vs any antiviral combination therapy (2.20). CONCLUSIONS: In this series of patients with hematologic malignancies and COVID-19, mortality was associated with higher age, more comorbidities, type of hematological malignancy and type of antineoplastic therapy. Further studies and long-term follow-up are required to validate these criteria for risk stratification.

Sequence-Dependent Correlated Segments in the Intrinsically Disordered Region of ChiZ.

How sequences of intrinsically disordered proteins (IDPs) code for their conformational dynamics is poorly understood. Here, we combined NMR spectroscopy, small-angle X-ray scattering (SAXS), and molecular dynamics (MD) simulations to characterize the conformations and dynamics of ChiZ1-64. MD simulations, first validated by SAXS and secondary chemical shift data, found scant α-helices or ß-strands but a considerable propensity for polyproline II (PPII) torsion angles. Importantly, several blocks of residues (e.g., 11-29) emerge as "correlated segments", identified by their frequent formation of PPII stretches, salt bridges, cation-π interactions, and sidechain-backbone hydrogen bonds. NMR relaxation experiments showed non-uniform transverse relaxation rates (R2s) and nuclear Overhauser enhancements (NOEs) along the sequence (e.g., high R2s and NOEs for residues 11-14 and 23-28). MD simulations further revealed that the extent of segmental correlation is sequence-dependent; segments where internal interactions are more prevalent manifest elevated "collective" motions on the 5-10 ns timescale and suppressed local motions on the sub-ns timescale. Amide proton exchange rates provides corroboration, with residues in the most correlated segment exhibiting the highest protection factors. We propose the correlated segment as a defining feature for the conformations and dynamics of IDPs.

False positives in using the zymogram assay for identification of peptidoglycan hydrolases.

Zymogram assays have been used extensively to identify novel peptidoglycan hydrolases. In this study it is reported that the zymogram is susceptible to false positive results when highly positively charged proteins are assayed. As an example, we report on the case of the ChiZ membrane protein from the Mycobacterium tuberculosis divisome, which previously was described as a peptidoglycan hydrolase. Even though the full length ChiZ protein was able to produce positive assay results, other direct methods for measuring peptidoglycan hydrolysis do not provide convincing evidence that ChiZ has peptidoglycan hydrolysis activity. We show that the false positive result is produced by the highly positively charged N-terminal region of ChiZ. Thus, we developed a zymogram control that can be used to identify false positives results. This control assay lacks the refolding step in the normal zymogram assay. For lysozyme the control assay shows no activity, while the N-terminal region of ChiZ shows a false positive result. Given the limitations of the zymogram assay to reliably identify peptidoglycan hydrolases, we recommend using the zymogram control assay together with other methods to evaluate possible peptidoglycan hydrolysis activity.

Binding of dihydroxynaphthyl aryl ketones to tubulin colchicine site inhibits microtubule assembly.

Dihydroxynaphthyl aryl ketones 1-5 have been evaluated for their abilities to inhibit microtubule assembly and the binding to tubulin. Compounds 3, 4 and 5 displayed competitive inhibition against colchicine binding, and docking analysis showed that they bind to the tubulin colchicine-binding pocket inducing sheets instead of microtubules. Remarkable differences in biological activity observed among the assayed compounds seem to be related to the structure and position of the aryl substituent bonded to the carbonyl group. Compounds 2, 3 and 4, which contain a heterocyclic ring, presented higher affinity for tubulin compared to the carbocyclic analogue 5. Compound 4 showed the best affinity of the series, with an IC50 value of 2.1 µM for microtubule polymerization inhibition and a tubulin dissociation constant of 1.0 ± 0.2 µM, as determined by thermophoresis. Compound 4 was more efficacious in disrupting microtubule assembly in vitro than compound 5 although it contains the trimethoxyphenyl ring present in colchicine. Hydrogen bonds with Asn101 of α-tubulin seem to be responsible for the higher affinity of compound 4 respects to the others.