RESUMO
Fifth-generation (5G) and beyond networks are expected to serve large numbers of user equipments (UEs). Grant-based random access (RA) protocols are efficient when serving human users, typically with large data volumes to transmit. The strongest user collision resolution (SUCRe) is the first protocol that effectively uses the many antennas at the 5G base station (BS) to improve connectivity performance. In this paper, our proposal involves substituting the retransmission rule of the SUCRe protocol with a neural network (NN) to enhance the identification of the strongest user and resolve collisions in a decentralized manner on the UEs' side. The proposed NN-based procedure is trained offline, admitting different congestion levels of the system, aiming to obtain a single setup able to operate with different numbers of UEs. The numerical results indicate that our method attains substantial connectivity performance improvements compared to other protocols without requiring additional complexity or overhead. In addition, the proposed approach is robust regarding variations in the number of BS antennas and transmission power while improving energy efficiency by requiring fewer attempts on the RA stage.
RESUMO
It is uncertain whether gastrointestinal (GI) infection caused by viral and bacterial pathogens may predispose to gastrointestinal acute Graft-versus-host disease (aGvHD-GI) in allogeneic hematopoietic stem cell transplant recipients (allo-HSCT). We investigated the potential association between detection of enteropathogenic viruses or bacteria in stools and subsequent occurrence of aGvHD-GI in a cohort of 121 allo-HSCT patients. Eighty-six out of 121 patients (71%) had acute diarrhea and underwent screening for primary GI pathogens by molecular diagnostic methods. One or more GI pathogens were detected in 27 out of the 86 patients with diarrhea (31.3%). Specifically, Clostridioides difficile was found in 16 patients (18.6%), enteropathogenic viruses in 11 patients (12.7%) (Astrovirus, n = 4; Norovirus, n = 2; Sapovirus, n = 2; Adenovirus, n = 2; and Rotavirus, n = 1), and Campylobacter spp. in two patients (2.3%). Thirty patients were diagnosed with all grade aGvHD-GI by histopathology. Detection of primary GI pathogens was achieved in 12 out of 30 patients (Clostridium difficile, n = 5; enteric viruses, n = 8; Campylobacter spp., n = 1) who either subsequently developed (n = 9) or previously had (n = 3) grade I-IV IaGvHD (n = 9). Neither the detection of these microorganisms (all combined), enteric viruses, nor C. difficile was significantly associated with subsequent aGvHD-GI development in Cox models (hazard ratio [HR] = 1.11, p = .80; HR = 1.64, p = .62; HR = 0.75, p = .64, respectively). Analogous results were obtained when grade II-IV aGvHD-GI was selected as the clinical outcome. In summary, data in the current study did not support an association between GI infection and subsequent occurrence of aGvHD-GI in an unselected cohort of allo-HSCT recipients.
Assuntos
Infecções Bacterianas/complicações , Gastroenteropatias/microbiologia , Gastroenteropatias/virologia , Doença Enxerto-Hospedeiro/etiologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Viroses/complicações , Doença Aguda , Adolescente , Adulto , Idoso , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/patogenicidade , Suscetibilidade a Doenças , Fezes , Feminino , Gastroenteropatias/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Estudos Prospectivos , Vírus/classificação , Vírus/genética , Vírus/isolamento & purificação , Adulto JovemRESUMO
Torque Teno virus (TTV) DNA load in blood may act as a marker of immune competence after allogeneic hematopoietic stem cell transplant recipients (allo-HSCT). Conflicting data have been reported as to the value of this biomarker for anticipating acute Graft versus host disease (aGvHD) occurrence. Here, we hypothesized that quantitation of TTV DNA load in stool specimens early after allo-HSCT could be used to identify patients at high risk of acute intestinal graft versus host disease (aIGvHD). In this prospective two-center study, we recruited a total of 83 nonconsecutive adult patients undergoing allo-HSCT. The study period comprised the first 120 days after allo-HSCT. TTV DNA was quantitated in paired stool samples collected at a median of 2 days prior to cell infusion and at a median of 14 days after allo-HSCT by real-time PCR. Thirty-seven patients developed aGVHD, of whom 25 had aIGVHD (diagnosed at a median of 42 days after allo-HSCT). Median TTV DNA load values in posttransplant stools specimens were comparable (P = .34) in patients with or without subsequent aIGvHD; nevertheless, a falling trajectory (decrease in TTV DNA load >0.5 log10 copies/0.1 g) in paired pretransplant and posttransplant specimens was independently associated with the occurrence of aIGvHD (OR, 5.2; 95% CI, 1.3-21.3; P = .02). Notably, displaying a rising trajectory had a negative predictive value of 87.5% for aIGvHD. In summary, in this hypothesis-generating study, we suggest that the decrease in TTV DNA load from baseline in stool specimens may identify patients at risk of aIGVHD.
Assuntos
Infecções por Vírus de DNA , Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Torque teno virus , Adulto , DNA Viral , Humanos , Cinética , Estudos Prospectivos , Carga ViralRESUMO
The potential role of active CMV infection in promoting acute Graft-versus-Host Disease (aGvHD) in allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a matter of debate. We further addressed this issue conducting a retrospective, observational, multicenter study of 632 patients subjected to allogeneic peripheral blood HSCT at 20 Spanish centers. Monitoring of CMV DNA load in plasma or whole blood was performed by real-time PCR assays. Cumulative incidence of CMV DNAemia was 48.9% (95% CI, 45%-52.9%), of any grade aGvHD, 45.6; 95% (CI, 41.3%-50.1%), and of grade II-IV aGvHD, 30.7 (95% CI, 24.9%-36.4%). Overall, development of CMV DNAemia at any level resulted in an increased risk of subsequent all grade (HR, 1.38; 95% CI, 1.08 - 1.76; P = .009) or grade II-IV (HR, 1.58; 95% CI, 1.22 - 2.06; P = .001) aGvHD. The increased risk of aGvHD linked to prior occurrence of CMV DNAemia was similar to the above when only clinically significant episodes were considered for the analyses (HR for all grade aGvHD, 1.48; 95% CI, 1.13 - 1.91; P = .041, and HR for grade II-IV aGvHD, 1.53; 95% CI. 1.13-1.81; P = .04). The CMV DNA doubling time in blood was comparable overall in episodes of CMV DNAemia whether followed by aGvHD or not. Whether CMV replication is a surrogate risk marker of aGvHD or it is causally involved is an important question to be addressed in future experimental research.
Assuntos
Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Transplante de Células-Tronco de Sangue Periférico , Citomegalovirus/genética , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Estudos RetrospectivosRESUMO
BACKGROUND: Data have been published suggesting a bidirectional interaction between cytomegalovirus (CMV) infection and acute graft-versus-host disease (aGvHD) in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. Here, we hypothesized that prospective CMV DNA monitoring in stool specimens may be useful for predicting subsequent occurrence of intestinal aGvHD (IaGvHD). METHODS: This two-center study enrolled 121 consecutive adult patients undergoing any modality of allo-HSCT. A total of 1,009 stool specimens were collected (a median of 7 specimens/patient; range, 1-18). CMV DNA monitoring in stools and plasma was performed using real-time PCR assays. RESULTS: CMV DNA was detected in stools in 20 patients (cumulative incidence, 16.9%; 95% CI, 6.3%-31.8%). Median CMV DNA level in stool specimens was 1,258 IU/0.1g (range, 210-4,087 IU/0.1 g). All these patients and their donors were CMV seropositive, and 16 of the 20 patients also had CMV DNAemia, while 4 patients had CMV DNA detected in stools without CMV DNAemia. No correlation was found between CMV DNA loads in plasma and stools (P = .40). Prior CMV DNAemia, aGvHD, or IaGvHD were not associated with presence of CMV DNA in feces. IaGvHD was present in 30 patients, in 5 of whom CMV DNA was detected in stools. Neither detection of CMV DNA in feces nor in plasma was associated with subsequent IaGvHD (OR, 0.67; 95% CI, 0.18-2.52; P = .55 and OR, 0.86; 95% CI, 0.38-1.96; P = .71, respectively). No patient in this cohort had CMV end-organ disease within the study period. CONCLUSION: Our study failed to provide evidence pointing to a reciprocal interaction between GI CMV infection and IaGvHD. CMV DNA monitoring in stools seems of no value to anticipate occurrence of IaGvHD.
Assuntos
Infecções por Citomegalovirus , DNA Viral/isolamento & purificação , Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Carga Viral , Adulto , Citomegalovirus/genética , Infecções por Citomegalovirus/complicações , Fezes/virologia , Doença Enxerto-Hospedeiro/diagnóstico , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Enteropatias/diagnóstico , Estudos ProspectivosAssuntos
COVID-19/genética , Glucuronidase/genética , Sistema Respiratório/virologia , SARS-CoV-2/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Técnicas de Laboratório Clínico/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Sensibilidade e Especificidade , Adulto JovemRESUMO
OBJECTIVES: Studies comparing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA load in the upper respiratory tract (URT) between children and adults-who either presented with coronavirus disease 2019 (COVID-19) or were asymptomatic-have yielded inconsistent results. Here, we conducted a retrospective, single-centre study to address this issue. PATIENTS AND METHODS: Included were 1184 consecutive subjects (256 children and 928 adults) testing positive for SARS-CoV-2 RNA in nasopharyngeal exudates (NPs); of these, 424 (121 children and 303 adults) had COVID-19 and 760 (135 children and 625 adults) were asymptomatic close contacts of COVID-19 patients. SARS-CoV-2 RNA testing was carried out using the TaqPath COVID-19 Combo Kit (Thermo Fisher Scientific, MS, USA). The AMPLIRUN® TOTAL SARS-CoV-2 RNA Control (Vircell SA, Granada, Spain) was used for estimating SARS-CoV-2 RNA loads (in copies/mL). SARS-CoV-2 RNA loads at the time of laboratory diagnosis (single specimen/patient) were used for comparison purposes. RESULTS: Median initial SARS-CoV-2 RNA load was lower (p 0.094) in children (6.98 log10 copies/mL, range 3.0-11.7) than in adults (7.14 log10 copies/mL, range 2.2-13.4) with COVID-19. As for asymptomatic individuals, median SARS-CoV-2 RNA load was comparable (p 0.97) in children (6.20 log10 copies/mL, range 1.8-11.6) and adults (6.48 log10 copies/mL, range 1.9-11.8). Children with COVID-19 symptoms displayed SARS-CoV-2 RNA loads (6.98 log10 copies/mL, range 3.0-11.7) comparable to those of their asymptomatic counterparts (6.20 log10 copies/mL, range 1.8-11.6) (p 0.61). Meanwhile in adults, median SARS-CoV-2 RNA load was significantly higher in symptomatic (7.14 log10 copies/mL, range 2.2-13.4) than in asymptomatic subjects (6.48 log10 copies/mL, range 1.9-11.8) (p < 0.001). Overall, the observed URT SARS-CoV-2 RNA clearance rate was faster in children than in adults. CONCLUSIONS: Based on viral load data at the time of diagnosis, our results suggest that SARS-CoV-2-infected children, with or without COVID-19, may display NP viral loads of comparable magnitude to those found in their adult counterparts. However, children may have shorter viral shedding than adults.
Assuntos
COVID-19 , Nasofaringe/virologia , RNA Viral , SARS-CoV-2 , Carga Viral , Adulto , Infecções Assintomáticas , COVID-19/diagnóstico , Criança , Humanos , RNA Viral/isolamento & purificação , Estudos RetrospectivosRESUMO
OBJECTIVES: To our knowledge no previous study has assessed the performance of a rapid antigen diagnostic immunoassay (RAD) conducted at the point of care (POC). We evaluated the Panbio™ COVID-19 Ag Rapid Test Device for diagnosis of coronavirus 2019 disease (COVID-19) in symptomatic patients (n = 412) attending primary healthcare centres. METHODS: RAD was performed immediately after sampling following the manufacturer's instructions (reading at 15 min). RT-PCRs were carried out within 24 h of specimen collection. Samples displaying discordant results were processed for culture in Vero E6 cells. Presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in cell cultures was confirmed by RT-PCR. RESULTS: Out of 412 patients, 43 (10.4%) tested positive by RT-PCR and RAD, and 358 (86.9%) tested negative by both methods; discordant results (RT-PCR+/RAD-) were obtained in 11 patients (2.7%). Overall specificity and sensitivity of rapid antigen detection (RAD) was 100% (95%CI 98.7-100%) and 79.6% (95%CI 67.0-88.8%), respectively, taking RT-PCR as the reference. Overall RAD negative predictive value for an estimated prevalence of 5% and 10% was 99% (95%CI 97.4-99.6%) and 97.9% (95%CI 95.9-98.9), respectively. SARS-CoV-2 could not be cultured from specimens yielding RT-PCR+/RAD- results (n = 11). CONCLUSION: The Panbio™ COVID-19 Ag Rapid Test Device performed well as a POC test for early diagnosis of COVID-19 in primary healthcare centres. More crucially, the data suggested that patients with RT-PCR-proven COVID-19 testing negative by RAD are unlikely to be infectious.
Assuntos
Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , Testes Imediatos , SARS-CoV-2/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Instituições de Assistência Ambulatorial , Antígenos Virais/análise , Teste de Ácido Nucleico para COVID-19 , Criança , Pré-Escolar , Diagnóstico Precoce , Feminino , Humanos , Imunoensaio , Lactente , Masculino , Pessoa de Meia-Idade , Nasofaringe/virologia , Kit de Reagentes para Diagnóstico , SARS-CoV-2/genética , SARS-CoV-2/imunologia , Sensibilidade e Especificidade , Adulto JovemRESUMO
PURPOSE: Fast identification of bacteria directly from positive blood cultures (BCs) by matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS) can be achieved either using the MALDI Sepsityper kit (protein extraction method) or after a short-term pre-cultivation step on solid medium. We developed a new method that involves short-term enrichment of positive BCs in brain-heart infusion broth (BHI) prior to MALDI-TOF MS analysis. METHODOLOGY: Eighty-four BCs flagged as positive were included in this study; these were processed in parallel either directly using the MALDI Sepsityper kit or following a short-term culture either in BHI or on Columbia blood agar with 5â% sheep blood (CBA). RESULTS: Bacterial species were successfully identified in 91.6, 89.2 and 65.4â% of cases after pre-cultivation for 4 h in BHI, on CBA, or by using the MALDI Sepsityper kit, respectively. Overall, the mean incubation time to correct identification was shorter when pre-cultures were performed in BHI; the mean time for Gram-negative rods was 78.2 min in BHI and 108.2 min on CBA (P=0.045), and the mean time for Gram-positive cocci was 128.5 min in BHI and 169.6 min on CBA (P=0.013). CONCLUSION: Short-term enrichment of BCs in BHI accelerates identification of a number of bacterial species by MALDI-TOF MS. Further prospective studies are needed to validate our method and gauge its potential clinical impact on the management of bloodstream bacterial infections.
Assuntos
Hemocultura , Meios de Cultura/química , Bactérias Gram-Negativas/isolamento & purificação , Cocos Gram-Positivos/isolamento & purificação , Infecções Bacterianas/diagnóstico , Técnicas Bacteriológicas , Humanos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
OBJECTIVES: We sought to test the efficacy and safety of the implantation of a stent covered with biosynthetic cellulose compared to a conventional bare-metal stent (BMS) in a rabbit iliac artery model. BACKGROUND: Biosynthetic cellulose is a biocompatible film used in several fields of medicine. Stents covered with biosynthetic cellulose are devices with the potential of achieving total lesion coverage, acting as a physical barrier to the migration of smooth muscle cells from the artery wall to the arterial lumen, and capturing circulating endothelial progenitor cells that may form a functional endothelial layer. METHODS AND RESULTS: Seven BMS and 7 stents covered with biosynthetic cellulose were implanted in the iliac arteries of 7 rabbits. Angiographic restudy and morphometric analysis of the specimens were performed after 4 weeks. No intrastent angiographic restenosis was observed, either with BMS or with stents covered with biosynthetic cellulose. There was also no acute or late vessel occlusion caused by stent thrombosis in either group. In the BMS and biosynthetic cellulose stented groups, respectively, mean neointimal thicknesses were 0.18 +/- 0.02 mm and 0.35 +/- 0.02 mm*; lumen area, 4.6 +/- 0.43 mm2 and 4.04 +/- 0.42 mm2; neointimal area, 0.58 +/- 0.09 mm2 and 2.13 +/- 0.11 mm(2)*; % lumen, 79.09 +/- 1.6% and 58.44 +/- 3.26%*; % stenosis, 10.97 +/- 1.23% and 35.55 +/- 3.39%* (*p < 0.05 vs. bare-metal). CONCLUSIONS: Implantation of stents covered with biosynthetic cellulose was safe, with no acute or late vessel occlusion caused by stent thrombosis, although it resulted in a more pronounced absolute neointimal thickness when compared to BMS.