Seasonal changes of lower respiratory tract infections in lung transplant recipients during the first post-transplant year: The Hungarian experience.

BACKGROUND: After lung transplantation (LuTX) a high level of immunosuppression is needed to prevent rejection of the graft. Together with earlier colonization by pathogens, immunosuppression makes recipients more susceptible to infections, especially during the first postoperative year. As seasonality of lower respiratory tract infections (LRTI) is well-known in chronic lung diseases, we assessed seasonal changes of pathogen spectrum and number of infections in the first postoperative year in LuTX recipients. METHODS: LRTI were analyzed in 28 Hungarian adult LuTX patients. Incidence and spectrum of microorganism causing LRTI were evaluated according to post-transplant time and seasonal temperature and humidity changes. RESULTS: A total of 69 cases of LRTI were registered (average: 1.9 cases/patient; range: 0-14). Gram-negative=59, gram-positive=26, and fungal=31 pathogens were detected, with polymicrobial samples in 46% of all cases. Increased number of LRTI was observed in the cold season (1.68±1.54 vs 0.79±0.92 case/month/patient, P<.01) and significant negative correlations were identified between the incidence of polymicrobial and bacterial infections and temperature (r2 =0.1535, P<.05, r2 =0.3144, P<.01, respectively). In addition, positive correlation was observed between polymicrobial infections and humidity (r2 =0.1403, P<.05). Higher incidence of LRTI was also noted in the cold season, when accounting for the differences in immunosuppression. CONCLUSION: Seasons influenced the incidence of LRTI in the first postoperative year in LuTX recipients. More intensive vigilance for possible gram-negative and polymicrobial infections is needed in these patients in cold and wet seasons in the continental climate zone, regardless of underlying disease.

Expiratory flow rate, breath hold and anatomic dead space influence electronic nose ability to detect lung cancer.

BACKGROUND: Electronic noses are composites of nanosensor arrays. Numerous studies showed their potential to detect lung cancer from breath samples by analysing exhaled volatile compound pattern ("breathprint"). Expiratory flow rate, breath hold and inclusion of anatomic dead space may influence the exhaled levels of some volatile compounds; however it has not been fully addressed how these factors affect electronic nose data. Therefore, the aim of the study was to investigate these effects. METHODS: 37 healthy subjects (44 ± 14 years) and 27 patients with lung cancer (60 ± 10 years) participated in the study. After deep inhalation through a volatile organic compound filter, subjects exhaled at two different flow rates (50 ml/sec and 75 ml/sec) into Teflon-coated bags. The effect of breath hold was analysed after 10 seconds of deep inhalation. We also studied the effect of anatomic dead space by excluding this fraction and comparing alveolar air to mixed (alveolar + anatomic dead space) air samples. Exhaled air samples were processed with Cyranose 320 electronic nose. RESULTS: Expiratory flow rate, breath hold and the inclusion of anatomic dead space significantly altered "breathprints" in healthy individuals (p < 0.05), but not in lung cancer (p > 0.05). These factors also influenced the discrimination ability of the electronic nose to detect lung cancer significantly. CONCLUSIONS: We have shown that expiratory flow, breath hold and dead space influence exhaled volatile compound pattern assessed with electronic nose. These findings suggest critical methodological recommendations to standardise sample collections for electronic nose measurements.

Remdesivir in Solid Organ Recipients for COVID-19 Pneumonia.

Solid organ transplant (SOT) recipients represent a vulnerable patient population and are of high risk for airborne viral infections, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). Treatment of COVID-19 is still challenging, as no proven therapeutic regimen is available for immunocompromised patients. Our aim was to evaluate the efficacy and safety of remdesivir (RDV) therapy in infected hospitalized SOT patients. All transplanted recipients (N = 25; lung: 19; kidney: 3, liver: 2, heart: 1) who needed hospital care were reviewed in the time period between September 2020 and May 2021 out of the 945 patients treated at the Department. Case control matched patients receiving RDV (all in need of supplementary oxygen) and standard of care (SOC) were included as controls. Among the 25 SOT patients (female:male = 11:14; average age = 53.2 ± 12.7 years), 15 received RDV medication (RDV-TX), and in 10 cases SOC treatment was used (SOC-TX). Significantly worse clinical score was noted in RDV patients compared with RDV-TX; however, transfer to a higher intensity care unit as well as 60-day survival of RDV-TX patients were significantly worse. All SOT fatalities within 60 days of follow-up were lung transplant recipients (6 out of 19 lung transplant patients). No adverse events were noted related to RDV therapy. In SOT patients, especially lung transplant recipients, with severe COVID-19 needing supplementary oxygen, RDV treatment was safe; however, outcome was significantly worse as compared with nontransplanted individuals with initially worse clinical parameters.

Long-term survival benefit of male and multimorbid COVID-19 patients with 5-day remdesivir treatment.

Background: Treatment of the coronavirus disease (COVID-19) is still challenging due to the lack of evidence-based treatment protocols and continuously changing epidemiological situations and vaccinations. Remdesivir (RDV) is among the few antiviral medications with confirmed efficacy for specific patient groups. However, real-world data on long-term outcomes for a short treatment course are scarce. Methods: This retrospective observational cohort study included real-life data collected during the second and third wave of the COVID-19 pandemic in Hungary (September 1, 2020-April 30, 2021) from inpatients at a University Center (n = 947). Participants consisted of two propensity score-matched cohorts (370/370 cases): Group RDV including patients receiving RDV and supplementary oxygen and Group standard of care (SOC) as control. The primary outcome was the effect of 5-day RDV treatment on 30- and 60-day all-cause mortality. Multivariate analyses were performed to assess the effect of RDV by different covariates. Results: Group RDV included significantly more patients from the alpha variant wave, with greater frequency of comorbidities diabetes and anemia, and larger degree of parenchymal involvement. All-cause mortality at 30- and 60-day were significantly lower in Group RDV compared to Group SOC. Significant risk reduction of 60-day all-cause mortality was observed for RDV treatment in men and patients with COPD or multiple comorbidities. Conclusions: Hospitalized COVID-19 patients with 5-day RDV treatment had significantly lower 30- and 60-day all-cause mortality, despite their more severe clinical condition. Men and patients with multiple comorbidities, including COPD, profited the most from RDV treatment in the long term. Due to the ongoing COVID-19 pandemic, effective treatment regimens are needed for hospitalized patients.

Decreased soluble adenylyl cyclase activity in cystic fibrosis is related to defective apical bicarbonate exchange and affects ciliary beat frequency regulation.

Human airway cilia contain soluble adenylyl cyclase (sAC) that produces cAMP upon HCO(3)(-)/CO(2) stimulation to increase ciliary beat frequency (CBF). Because apical HCO(3)(-) exchange depends on cystic fibrosis transmembrane conductance regulator (CFTR), malfunctioning CFTR might impair sAC-mediated CBF regulation in cells from patients with cystic fibrosis (CF). By Western blot, sAC isoforms are equally expressed in normal and CF airway epithelial cells, but CBF decreased more in CF than normal cells upon increased apical HCO(3)(-)/CO(2) exposure in part because of greater intracellular acidification from unbalanced CO(2) influx (estimated by 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) fluorescence). Importantly, ciliated cell-specific cAMP production (estimated by FRET fluorescence ratio changes of tagged cAMP-dependent protein kinase (PKA) subunits expressed under a ciliated cell-specific promoter) in response to increased apical HCO(3)(-)/CO(2) perfusion was higher in normal compared with CF cells. Inhibition of bicarbonate influx via CFTR (CFTR(inh)172) and inhibition of sAC (KH7) and PKA activation (H89) led to larger CBF declines in normal cells, now comparable with changes seen in CF cells. These inhibitors also reduced FRET changes in normal cells to the level of CF cells with the expected exception of H89, which does not prevent dissociation of the fluorescently tagged PKA subunits. Basolateral permeabilization and subsequent perfusion with HCO(3)(-)/CO(2) rescued CBF and FRET changes in CF cells to the level of normal cells. These results suggest that CBF regulation by sAC-produced cAMP could be impaired in CF, thereby possibly contributing to mucociliary dysfunction in this disease, at least during disease exacerbations when airway acidification is common.

Severe hypoxaemia without dyspnoe in COVID-19 pneumonia / Súlyos hypoxaemia légszomj nélkül COVID-19-pneumoniában.

Összefoglaló. Számos közlemény született arról, hogy a COVID-19-pneumoniás betegek jelentos hányadában az artériás parciális oxigéntenzió kifejezetten alacsony, mégsem jellemzo a dyspnoe, és a pulzusoximetria sem mutat - a csökkent oxigéntenzióval arányos - súlyos hypoxaemiát. A jelenséget "happy hypoxaemia" néven említik. Ugyanakkor a légszomjról nem panaszkodó, de súlyos alveolocapillaris O2-felvételi zavarban szenvedo COVID-19-pneumoniás betegek a legkisebb fizikai megterhelést sem turik, és állapotuk gyorsan kritikussá válhat, tehát a hypoxaemia mértékének idoben való felismerése kulcskérdés. A jelen közleményben egy ilyen eset rövid ismertetése után összefoglaljuk a súlyos, de tünetmentes hypoxaemia hátterében meghúzódó élettani okokat. Ezek között szerepel a hypocapnia (respiratoricus alkalosis) is, mely alacsony oxigéntenzió mellett is a hemoglobin viszonylag megtartott oxigénszaturációját eredményezi. Ezért a mindennapi COVID-19-ellátásban a megismételt artériásvérgáz-meghatározások jelentosége nem hangsúlyozható eléggé. Orv Hetil. 2021; 162(10): 362-365. Summary. Many COVID-19 patients have very low arterial partial oxigen tension while severe dyspnoe does not develop. Pulse oxymetry indicates only moderate reduction of arterial O2 saturation in these patients. The phenomenon is named "happy hypoxaemia". Lack of (severe) dyspnoe and only moderately decreased O2 saturation in severely impaired alveolo-capillary O2 uptake may partially be explained by an increased oxygen affinity of hemoglobin in the presence of low arterial partial pressure of CO2. The latter results from increased alveolar ventilation, while low partial pressure of O2 in COVID-19 patients reflects right-to-left shunting of pulmonary blood flow and ventilation-perfusion mismatch of the diseased lungs. While such patients may have mild complaints as related to the real impairment of alveolo-capillary oxygen exchange, severe hypoxaemia is a negative prognostic factor of outcome in this state where severe clinical deterioration may rapidly appear. The latter circumstance together with the unusual relationship of O2 partial pressure and O2 saturation of hemoglobin in COVID-19 emphasize the importance of repeated complete arterial blood gas analyses in these patients. Orv Hetil. 2021; 162(10): 362-365.

Soluble adenylyl cyclase is localized to cilia and contributes to ciliary beat frequency regulation via production of cAMP.

Ciliated airway epithelial cells are subject to sustained changes in intracellular CO(2)/HCO(3)(-) during exacerbations of airway diseases, but the role of CO(2)/HCO(3)(-)-sensitive soluble adenylyl cyclase (sAC) in ciliary beat regulation is unknown. We now show not only sAC expression in human airway epithelia (by RT-PCR, Western blotting, and immunofluorescence) but also its specific localization to the axoneme (Western blotting and immunofluorescence). Real time estimations of [cAMP] changes in ciliated cells, using FRET between fluorescently tagged PKA subunits (expressed under the foxj1 promoter solely in ciliated cells), revealed CO(2)/HCO(3)(-)-mediated cAMP production. This cAMP production was specifically blocked by sAC inhibitors but not by transmembrane adenylyl cyclase (tmAC) inhibitors. In addition, this cAMP production stimulated ciliary beat frequency (CBF) independently of intracellular pH because PKA and sAC inhibitors were uniquely able to block CO(2)/HCO(3)(-)-mediated changes in CBF (while tmAC inhibitors had no effect). Thus, sAC is localized to motile airway cilia and it contributes to the regulation of human airway CBF. In addition, CO(2)/HCO(3)(-) increases indeed reversibly stimulate intracellular cAMP production by sAC in intact cells.

Calcium-mediated, purinergic stimulation and polarized localization of calcium-sensitive adenylyl cyclase isoforms in human airway epithelia.

Purinergic stimulation of human airway epithelia results in a prolonged increase in ciliary beat frequency that depends on calcium-mediated cAMP production [Lieb, T., Wijkstrom Frei, C., Frohock, J.I., Bookman, R.J. and Salathe, M. (2002) Prolonged increase in ciliary beat frequency after short-term purinergic stimulation in human airway epithelial cells. J. Physiol. (Lond.) 538, 633-646]. Here, fully differentiated human airway epithelial cells in culture are shown to express calcium-stimulated transmembrane adenylyl cyclase (tmAC) isoforms (types 1, 3, and 8) by reverse transcription polymerase chain reaction. Immunohistochemistry of tracheal sections and fully differentiated airway epithelial cell cultures revealed polarized expression of these tmACs, with types 1 and 8 localized to the apical membrane and thus at the position required for ciliary regulation. Real-time, ciliated-cell specific cAMP production by tmACs upon apical, purinergic stimulation with UTP was confirmed using fluorescent energy resonance transfer between fluorescently tagged PKA subunits.

OVERVIEW OF A DIGITAL TOMOSYNTHESIS DEVELOPMENT: NEW APPROACHES FOR LOW-DOSE CHEST IMAGING.

Lung cancer has the highest mortality rate among all cancer types, and it has especially high occurrence in Hungary. Low-dose computed tomography (LDCT) has been proved to be a beneficial screening method for lung cancer, decreasing the mortality rate by 20 %. Because of the intensifying fears from X-ray radiation, there is a need to develop other modalities that might work with less radiation and have similar sensitivity in lung nodule finding. Digital tomosynthesis (DTS) may be such a modality that can be a real alternative to LDCT. The goal of this article is to summarise the first results of a Hungarian project for developing a DTS system extended with a computer-aided detection system. It describes the main approaches applied and the main benefits of using DTS based on the first clinical examinations.

Regulation of human airway ciliary beat frequency by intracellular pH.

pHi affects a number of cellular functions, but the influence of pHi on mammalian ciliary beat frequency (CBF) is not known. CBF and pHi of single human tracheobronchial epithelial cells in submerged culture were measured simultaneously using video microscopy (for CBF) and epifluorescence microscopy with the pH-sensitive dye BCECF. Baseline CBF and pHi values in bicarbonate-free medium were 7.2 +/- 0.2 Hz and 7.49 +/- 0.02, respectively (n = 63). Alkalization by ammonium pre-pulse to pHi 7.78 +/- 0.02 resulted in a 2.2 +/- 0.1 Hz CBF increase (P < 0.05). Following removal of NH4Cl, pHi decreased to 7.24 +/- 0.02 and CBF to 5.8 +/- 0.1 Hz (P < 0.05). Removal of extracellular CO2 to change pHi resulted in similar CBF changes. Pre-activation of cAMP-dependent protein kinase (10 microM forskolin), broad inhibition of protein kinases (100 microM H-7), inhibition of PKA (10 microM H-89), nor inhibition of phosphatases (10 microM cyclosporin + 1.5 microM okadaic acid) changed pHi-mediated changes in CBF, nor were they due to [Ca2+]i changes. CBF of basolaterally permeabilized human tracheobronchial cells, re-differentiated at the air-liquid interface, was 3.9 +/- 0.3, 5.7 +/- 0.4, 7.0 +/- 0.3 and 7.3 +/- 0.3 Hz at basolateral i.e., intracellular pH of 6.8, 7.2, 7.6 and 8.0, respectively (n = 18). Thus, intracellular alkalization stimulates, while intracellular acidification attenuates human airway CBF. Since phosphorylation and [Ca2+]i changes did not seem to mediate pHi-induced CBF changes, pHi may directly act on the ciliary motile machinery.

Norepinephrine transport by the extraneuronal monoamine transporter in human bronchial arterial smooth muscle cells.

Inhaled glucocorticosteroids (GSs) cause acute, alpha1-adrenoreceptor (AR)-mediated bronchial vasoconstriction. After release from sympathetic nerves, norepinephrine (NE) must be taken up into cells for deactivation by intracellular enzymes. Because postsynaptic cellular NE uptake is steroid sensitive, GSs could increase NE concentrations at alpha1-AR, causing vasoconstriction. We therefore evaluated mRNA expression of different NE transporters in human bronchial arterial smooth muscle and pharmacologically characterized NE uptake into these cells. RT-PCR demonstrated mRNA expression of the extraneuronal monoamine transporter (EMT) and organic cation transporter 1 (OCT-1). Fluorometric uptake assay showed time (within minutes)- and concentration-dependent NE uptake by freshly isolated bronchial arterial smooth muscle cells (SMC) with an estimated Km of 240 microM. Corticosterone and O-methylisoprenaline (1 microM each), but not desipramine, inhibited NE uptake, a profile indicative of NE uptake by EMT, but not OCT-1. Budesonide and methylprednisolone inhibited uptake with IC50 values of 0.9 and 5.6 microM, respectively. Corticosterone's action was reversible and not sensitive to RU-486 (GS receptor antagonist), actinomycin D (transcription inhibitor), or cycloheximide (protein synthesis inhibitor). Corticosterone made membrane impermeant by coupling to BSA also blocked NE uptake. Immunocytochemistry indicated a specific membrane binding site for corticosterone on bronchial arterial SMC. These data demonstrate that although human bronchial arterial SMC express OCT-1 and EMT, EMT is the predominant plasma membrane transporter for NE uptake. This process can be inhibited by GSs, likely via a specific membrane binding site. This nongenomic GS action (increasing NE concentrations at alpha1-AR) could explain acute bronchial vasoconstriction caused by inhaled GSs.