Development of clinical tools to estimate the breathing effort during high-flow oxygen therapy: A multicenter cohort study.

INTRODUCTION AND OBJECTIVES: Quantifying breathing effort in non-intubated patients is important but difficult. We aimed to develop two models to estimate it in patients treated with high-flow oxygen therapy. PATIENTS AND METHODS: We analyzed the data of 260 patients from previous studies who received high-flow oxygen therapy. Their breathing effort was measured as the maximal deflection of esophageal pressure (ΔPes). We developed a multivariable linear regression model to estimate ΔPes (in cmH2O) and a multivariable logistic regression model to predict the risk of ΔPes being >10 cmH2O. Candidate predictors included age, sex, diagnosis of the coronavirus disease 2019 (COVID-19), respiratory rate, heart rate, mean arterial pressure, the results of arterial blood gas analysis, including base excess concentration (BEa) and the ratio of arterial tension to the inspiratory fraction of oxygen (PaO2:FiO2), and the product term between COVID-19 and PaO2:FiO2. RESULTS: We found that ΔPes can be estimated from the presence or absence of COVID-19, BEa, respiratory rate, PaO2:FiO2, and the product term between COVID-19 and PaO2:FiO2. The adjusted R2 was 0.39. The risk of ΔPes being >10 cmH2O can be predicted from BEa, respiratory rate, and PaO2:FiO2. The area under the receiver operating characteristic curve was 0.79 (0.73-0.85). We called these two models BREF, where BREF stands for BReathing EFfort and the three common predictors: BEa (B), respiratory rate (RE), and PaO2:FiO2 (F). CONCLUSIONS: We developed two models to estimate the breathing effort of patients on high-flow oxygen therapy. Our initial findings are promising and suggest that these models merit further evaluation.

Inspiratory Effort and Respiratory Mechanics in Patients with Acute Exacerbation of Idiopathic Pulmonary fibrosis: A Preliminary Matched Control Study.

BACKGROUND: Patients with acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) may experience severe acute respiratory failure, even requiring ventilatory assistance. Physiological data on lung mechanics during these events are lacking. METHODS: Patients with AE-IPF admitted to Respiratory Intensive Care Unit to receive non-invasive ventilation (NIV) were retrospectively analyzed. Esophageal pressure swing (ΔPes) and respiratory mechanics before and after 2 hours of NIV were collected as primary outcome. The correlation between positive end-expiratory pressure (PEEP) levels and changes of in dynamic compliance (dynCRS) and PaO2/FiO2 ratio was assessed. Further, an exploratory comparison with a historical cohort of ARDS patients matched 1:1 by age, sequential organ failure assessment score, body mass index and PaO2/FiO2 level was performed. RESULTS: At baseline, AE-IPF patients presented a high respiratory drive activation with ΔPes = 27 (21-34) cmH2O, respiratory rate (RR) = 34 (30-39) bpm and minute ventilation (VE) = 21 (20-26) L/min. Two hours after NIV application, ΔPes, RR and VE values showed a significant reduction (16 [14-24] cmH2O, p<0.0001, 27 [25-30] bpm, p=0.001, and 18 [17-20] L/min, p=0.003, respectively) while no significant change was found in dynamic transpulmonary pressure, expiratory tidal volume (Vte), dynCRS and dynamic mechanical power. PEEP levels negatively correlated with PaO2/FiO2 ratio and dynCRS (r=-0.67, p=0.03 and r=-0.27, p=0.4, respectively). When compared to AE-IPF, ARDS patients presented lower baseline ΔPes, RR, VE and dynamic mechanical power. Differently from AE-IPF, in ARDS both Vte and dynCRS increased significantly following NIV (p=0.01 and p=0.004 respectively) with PEEP levels directly associated with PaO2/FiO2 ratio and dynCRS (r=0.24, p=0.5 and r=0.65, p=0.04, respectively). CONCLUSIONS: In this study, patients with AE-IPF showed a high inspiratory effort, whose intensity was reduced by NIV application without a significant improvement in respiratory mechanics. In an exploratory analysis, AE-IPF patients showed a different mechanical behavior under spontaneous unassisted and assisted breathing compared with ARDS patients of similar severity.

Association between respiratory distress time and invasive mechanical ventilation in COVID-19 patients: A multicentre regional cohort study.

AIM: To determine whether the duration of respiratory distress symptoms in severe COVID-19 pneumonia affects the need for invasive mechanical ventilation and clinical outcomes. MATERIALS AND METHODS: An observational multicentre cohort study of patients hospitalised in five COVID-19-designated ICUs of the University Hospitals of Emilia-Romagna Region. Patients included were adults with pneumonia due to SARS-CoV-2 with PaO2/FiO2 ratio <300 mmHg, respiratory distress symptoms, and need for mechanical ventilation (invasive or non-invasive). Exclusion criteria were an uncertain time of respiratory distress, end-of-life decision, and mechanical respiratory support before hospital admission. MEASUREMENTS AND MAIN RESULTS: We analysed 171 patients stratified into tertiles according to respiratory distress duration (distress time, DT) before application of mechanical ventilation support. The rate of patients requiring invasive mechanical ventilation was significantly different (p < 0.001) among the tertiles: 17/57 patients in the shortest duration, 29/57 in the intermediate duration, and 40/57 in the longest duration. The respiratory distress time significantly increased the risk of invasive ventilation in the univariate analysis (OR 5.5 [CI 2.48-12.35], p = 0.003). Multivariable regression analysis confirmed this association (OR 10.7 [CI 2.89-39.41], p < 0.001). Clinical outcomes (mortality and hospital stay) did not show significant differences between DT tertiles. DISCUSSION: Albeit preliminary and retrospective, our data raised the hypothesis that the duration of respiratory distress symptoms may play a role in COVID-19 patients' need for invasive mechanical ventilation. Furthermore, our observations suggested that specific strategies may be directed towards identifying and managing early symptoms of respiratory distress, regardless of the levels of hypoxemia and the severity of the dyspnoea itself.

Prevalence and development of chronic critical illness in acute patients admitted to a respiratory intensive care setting.

INTRODUCTION: Chronic Critical Illness (chronic CI) is a condition associated to patients surviving an episode of acute respiratory failure (ARF). The prevalence and the factors associated with the development of chronic CI in the population admitted to a Respiratory Intensive Care Unit (RICU) have not yet been clarified. METHODS: An observational prospective cohort study was undertaken at the RICU of the University Hospital of Modena (Italy). Patients mechanically ventilated with ARF in RICU were enrolled. Demographics, severity scores (APACHEII, SOFA, SAPSII), and clinical condition (septic shock, pneumonia, ARDS) were recorded on admission. Respiratory mechanics and inflammatory-metabolic blood parameters were measured both on admission and over the first week of stay. All variables were tested as predictors of chronic CI through univariate and multivariate analysis. RESULTS: Chronic CI occurred in 33 out of 100 patients observed. Higher APACHEII, the presence of septic shock, diaphragmatic dysfunction (DD) at sonography, multidrug-resistant (MDR) bacterial infection, the occurrence of a second infection during stay, and a C-reactive protein (CRP) serum level inceasing 7 days over admission were associated with chronic CI. Septic shock was the strongest predictor of chronic CI (AUC = 0.92 p < 0.0001). CONCLUSIONS: Chronic CI is frequent in patients admitted to RICU and mechanically ventilated due to ARF. Infection-related factors seem to play a major role as predictors of this syndrome.

Prokineticin receptor identified by phage display is an entry receptor for Trypanosoma cruzi into mammalian cells.

Trypanosoma cruzi trypomastigotes invade a great variety of mammalian cells, with several molecules being implicated in this complex event. Herein, the sequence GGIALAG present in prokineticin-2 receptor (PKR2), selected by phage display technology, is described as a new T. cruzi receptor for the Tc85 group of glycoproteins belonging to the gp85/TS superfamily and involved in cellular invasion of mammalian hosts. This finding is confirmed by the inhibitory activity of MCF10-A (human mammary) cell invasion by T. cruzi either by anti-PKR2 antibodies (77%) or GGIALAG-synthetic peptide (42%). Furthermore, interference RNA (iRNA) inhibition of PKR2 expression in MCF10-A cells reduces T. cruzi invasion by 50%. The binding site of Tc85 to PKR2 was localized at the C-terminal end of the molecule, upstream of the conserved FLY sequence, previously implicated in parasite cell invasion. PKR2, a receptor formed by seven membrane-spanning α-helical segments, is mainly present in the central nervous system, peripheral organs, and mature blood cells. Due to its wide distribution, PKR2 could be a suitable receptor for T. cruzi natural infection, contributing to the parasite dissemination throughout the mammalian organism. These findings augment the number and diversity of possible in vivo receptors for T. cruzi and reassure the multiplicity of Tc85 binding sites to mammalian hosts.

Selection of binding targets in parasites using phage-display and aptamer libraries in vivo and in vitro.

Parasite infections are largely dependent on interactions between pathogen and different host cell populations to guarantee a successful infectious process. This is particularly true for obligatory intracellular parasites as Plasmodium, Toxoplasma, and Leishmania, to name a few. Adhesion to and entry into the cell are essential steps requiring specific parasite and host cell molecules. The large amount of possible involved molecules poses additional difficulties for their identification by the classical biochemical approaches. In this respect, the search for alternative techniques should be pursued. Among them two powerful methodologies can be employed, both relying upon the construction of highly diverse combinatorial libraries of peptides or oligonucleotides that randomly bind with high affinity to targets on the cell surface and are selectively displaced by putative ligands. These are, respectively, the peptide-based phage display and the oligonucleotide-based aptamer techniques. The phage display technique has been extensively employed for the identification of novel ligands in vitro and in vivo in different areas such as cancer, vaccine development, and epitope mapping. Particularly, phage display has been employed in the investigation of pathogen-host interactions. Although this methodology has been used for some parasites with encouraging results, in trypanosomatids its use is, as yet, scanty. RNA and DNA aptamers, developed by the SELEX process (Systematic Evolution of Ligands by Exponential Enrichment), were described over two decades ago and since then contributed to a large number of structured nucleic acids for diagnostic or therapeutic purposes or for the understanding of the cell biology. Similarly to the phage display technique scarce use of the SELEX process has been used in the probing of parasite-host interaction. In this review, an overall survey on the use of both phage display and aptamer technologies in different pathogenic organisms will be discussed. Using these techniques, recent results on the interaction of Trypanosoma cruzi with the host will be highlighted focusing on members of the 85 kDa protein family, a subset of the gp85/TS superfamily.

In vivo infection by Trypanosoma cruzi: the conserved FLY domain of the gp85/trans-sialidase family potentiates host infection.

Trypanosoma cruzi is a protozoan parasite that infects vertebrates, causing in humans a pathological condition known as Chagas' disease. The infection of host cells by T. cruzi involves a vast collection of molecules, including a family of 85 kDa GPI-anchored glycoproteins belonging to the gp85/trans-sialidase superfamily, which contains a conserved cell-binding sequence (VTVXNVFLYNR) known as FLY, for short. Herein, it is shown that BALB/c mice administered with a single dose (1 µg/animal, intraperitoneally) of FLY-synthetic peptide are more susceptible to infection by T. cruzi, with increased systemic parasitaemia (2-fold) and mortality. Higher tissue parasitism was observed in bladder (7·6-fold), heart (3-fold) and small intestine (3·6-fold). Moreover, an intense inflammatory response and increment of CD4+ T cells (1·7-fold) were detected in the heart of FLY-primed and infected animals, with a 5-fold relative increase of CD4+CD25+FoxP3+ T (Treg) cells. Mice treated with anti-CD25 antibodies prior to infection, showed a decrease in parasitaemia in the FLY model employed. In conclusion, the results suggest that FLY facilitates in vivo infection by T. cruzi and concurs with other factors to improve parasite survival to such an extent that might influence the progression of pathology in Chagas' disease.

La coccidioidomicosis en Argentina, 1892-2009 / Coccidioidomycosis in Argentina, 1892-2009

Los casos clínicos de coccidioidomicosis en Argentina son pocos y han tenido lugar fundamentalmente en la extensa región árida precordillerana. Este trabajo tiene como objetivos realizar una revisión retrospectiva del total de casos de coccidioidomicosis documentados en Argentina desde el año 1892 hasta 2009 y describir una serie de casos ocurridos en los últimos 4 años. En 117 años se documentaron 128 casos. Desde la primera descripción de la enfermedad en 1892 hasta 1939 se registraron 6 casos; desde 1940 hasta 1999, 59 casos (6-14 casos cada 10 años); y los 63 casos restantes (49% del total histórico) se produjeron en el último decenio. La mediana de edad de los 34 pacientes registrados en el período 2006-2009 fue de 31 años (rango: 7-89), la relación hombre:mujer fue 1,3:1; 12 de estos individuos eran inmunocomprometidos. Veintiséis casos se confirmaron por examen microscópico, por cultivo o por ambos procedimientos; los casos restantes se confirmaron por serología. Todos los aislamientos recuperados fueron identificados como Coccidioides posadasii. Treinta pacientes residían en una amplia área geográfica con epicentro en el valle de Catamarca. Entre 2006 y 2009, la tasa de incidencia en la provincia de Catamarca se incrementó desde valores históricos inferiores a 0,5 casos cada 100 000 habitantes hasta 2,0 casos cada 100 000 habitantes. Este aumento sugiere una emergencia de la coccidioidomicosis en el área.

Clinical cases of coccidioidomycosis are rare in Argentina and are generally found in the large arid precordilleran area of the country. This study aims to perform a retrospective review of all coccidioidomycosis cases documented in the country from 1892 to 2009, and to describe those occurring in the last 4 years. One hundred and twenty eight cases were documented in the 117 year-period. Since the original description of the disease in 1892 until 1939, only 6 cases were registered; between 1940 and 1999, 59 (6-14/10 yrs) and the remaining 63 (49% of total cases) occurred in the last decade. The median age of 34 patients registered in 2006-2009 was 31 years (range: 7-89), male/female ratio was 1.3:1 and 12 patients were immunocompromised. Twenty-six cases were confirmed by direct microscopy and/or culture whereas the remaining ones by serology. All isolates were identified as Coccidioides posadasii. Thirty patients lived in a vast geographic region with epicenter in Catamarca Valley. Between 2006 and 2009, annual disease incidence rates in Catamarca Province increased from historical values below 0.5/100,000 to 2/100,000 inhabitants. Such increase suggests an emergency of coccidioidomycosis in that region.

[Coccidioidomycosis in Argentina, 1892-2009]. / La coccidioidomicosis en Argentina, 1892-2009.

Clinical cases of coccidioidomycosis are rare in Argentina and are generally found in the large arid precordilleran area of the country. This study aims to perform a retrospective review of all coccidioidomycosis cases documented in the country from 1892 to 2009, and to describe those occurring in the last 4 years. One hundred and twenty eight cases were documented in the 117 year-period. Since the original description of the disease in 1892 until 1939, only 6 cases were registered; between 1940 and 1999, 59 (6-14/10 yrs) and the remaining 63 (49% of total cases) occurred in the last decade. The median age of 34 patients registered in 2006-2009 was 31 years (range: 7-89), male/female ratio was 1.3:1 and 12 patients were immunocompromised. Twenty-six cases were confirmed by direct microscopy and/or culture whereas the remaining ones by serology. All isolates were identified as Coccidioides posadasii. Thirty patients lived in a vast geographic region with epicenter in Catamarca Valley. Between 2006 and 2009, annual disease incidence rates in Catamarca Province increased from historical values below 0.5/100,000 to 2/100,000 inhabitants. Such increase suggests an emergency of coccidioidomycosis in that region.

Growth inhibition and proapoptotic activity induction by IIF and valproic acid on RA-resistant leukemia cells.

All-trans retinoic acid (RA) induces complete remission in a high proportion of patients with acute promyelocytic leukemia (APL). Nevertheless, most of these patients develop RA resistance and relapse. In an attemp to mimic clinical conditions for the treatment of leukemia, a stably RA-resistant subclone of the human promyelocytic leukemia cell line HL60 (HL60-R) was developed to study the antiproliferative and proapoptotic effect of the retinoid IIF (6-OH-11-O-hydroxyphenantrene) in comparison with RA. Moreover whether the inhibitor of histone deacetylase (HDAC) activity, valproic acid (VPA), could enhance sensitivity to retinoids in HL60-R cells was evaluated. Finally, the effect of IIF on the expression of multidrug resistance-associated protein 1 (MRP1) and P-glycoprotein (P-gp) was evaluated. It was found that IIF strongly suppressed cell proliferation (as measured by growth curves) and induced apoptosis (as measured by DNA fragmentation and Annexin V detection assays), while RA was practically ineffective. The addition of VPA to IIF accentuated the antiproliferative effect of IIF alone and increased apoptosis; the combination of VPA with RA allowed growth arrest. Moreover IIF caused a reduction of transmembrane transporter expression, particularly of P-gp, as shown by Western blotting. Our results suggest that IIF may be useful in controlling the proliferation of RA-resistant leukemia cells, especially in combination with an HDAC inhibitor, such as VPA.

Identification of the B-cell tumor-specific molecular fingerprint using non-radiolabelled PCR consensus primers.

BACKGROUND: The complementarity determining region 3 (CDR3) of the immunoglobulin (Ig) heavy chain variable region (VH) is the most reliable molecular fingerprint for most if not all human B cells. The nucleotide sequence encoding for any B-cell tumor-specific VH CDR3 is currently identified by PCR sequencing based on procedures involving the usage of either radioactive materials, patient/family-specific primers, or bacterial cloning. PATIENTS AND METHODS: In six consecutive patients with follicular lymphoma we assessed the feasibility of a method that allows for identification of the tumor-specific VH CDR3 using consensus primers while avoiding both radioactive materials and bacterial cloning procedures. RESULTS: The tumor-specific VH CDR3 was successfully identified in all six patients in nearly half the time typically required by any other method currently utilized. The feasibility of the proposed method was not significantly affected either by the tumor-specific Ig isotype, or by the tumor infiltration in the original biopsy specimen. In the three patients for whom tumor specimen-derived hybridomas were available, the tumor-specific VH CDR3 was also found in at least 8 of 10 of them. CONCLUSIONS: The proposed method allows the ability to quickly identify the B-cell tumor-specific VH CDR3 using consensus primers while avoiding radioactive materials and bacterial cloning procedures.

Compound heterozygosity for two different amino-acid substitution mutations in the thrombopoietin receptor (c-mpl gene) in congenital amegakaryocytic thrombocytopenia (CAMT).

Congenital amegakaryocytic thrombocytopenia (CAMT) without physical anomalies is a rare disease, presenting isolated thrombocytopenia and megakaryocytopenia in infancy, which can evolve into aplastic anemia and leukemia. Recently, two heterozygous truncating mutations of the thrombopoietin (TPO) receptor MPL, coded by the c-mpl gene, were identified in a 10-year-old Japanese patient with CAMT transmitted in an autosomal recessive manner. Here, we report for the first time two different MPL amino-acid substitutions in a 2-year-old Italian boy with CAMT and compound heterozygosis for two (c-mpl point mutations. C-to-T transitions were detected on exons 5 and 12 at the 769 and 1904 cDNA nucleotide positions, respectively. The mutation in exon 5 substitutes an arginine with a cysteine (R257C) in the extracellular domain, 11 amino acids distant from the WSXWS motif conserved in the cytokine-receptor superfamily. The mutation in exon 12 substitutes a proline with a leucine (P635L) in the last amino acid of the C-terminal intracellular domain, responsible for signal transduction. As in the Japanese family, the mutations were both transmitted from the parents. TPO plasma levels were highly increased in the patient. The patient's 7-year-old brother, who was a candidate donor for allografting, turned out to be an asymptomatic heterozygous carrier of P635L and showed defective megakaryocyte colony formation from bone-marrow progenitor cells. The present study provides important confirmation that CAMT can be associated with (c-mpl) mutations.