Robustness of tissue oxygenation estimates by continuous wave space-resolved near infrared spectroscopy

Significance: Continuous wave near infrared spectroscopy (CW-NIRS) is widely exploited in clinics to estimate skeletal muscles and brain cortex oxygenation. Spatially resolved spectroscopy (SRS) is generally implemented in commercial devices. However, SRS suffers from two main limitations: the a priori assumption on the spectral dependence of the reduced scattering coefficient [μs'(λ)] and the modeling of tissue as homogeneous. Aim: We studied the accuracy and robustness of SRS NIRS. We investigated the errors in retrieving hemodynamic parameters, in particular tissue oxygen saturation (StO2), when μs'(λ) was varied from expected values, and when layered tissue was considered. Approach: We simulated hemodynamic variations mimicking real-life scenarios for skeletal muscles. Simulations were performed by exploiting the analytical solutions of the photon diffusion equation in different geometries: (1) semi-infinite homogeneous medium and constant μs'(λ); (2) semi-infinite homogeneous medium and linear changes in μs'(λ); (3) two-layered media with a superficial thickness s1=5, 7.5, 10 mm and constant μs'(λ). All simulated data were obtained at source-detector distances ρ=35, 40, 45 mm, and analyzed with the SRS approach to derive hemodynamic parameters (concentration of oxygenated and deoxygenated hemoglobin, total hemoglobin concentration, and tissue oxygen saturation, StO2) and their relative error. Results: Variations in μs'(λ) affect the estimated StO2 (up to ±10%), especially if changes are different at the two wavelengths. However, the main limitation of the SRS method is the presence of a superficial layer: errors strongly larger than 20% were retrieved for the estimated StO2 when the superficial thickness exceeds 5 mm. Conclusions: These results highlight the need for more sophisticated strategies (e.g., the use of multiple short and long distances) to reduce the influence of superficial tissues in retrieving hemodynamic parameters and warn the SRS users to be aware of the intrinsic limitation of this approach, particularly when exploited in the clinical environment

Non-invasive monitoring of canine tissue hemodynamics undergoing a hyperbaric chamber treatment (HBO2) by time domain near infrared spectroscopy

A novel technique to treat different diseases from inflammation to poisonous bites from snakes on small animals is the hyperbaric chamber treatment [1]. Non-invasive and real-time hemodynamic monitoring of patient's tissue could be useful to quantify the effect of oxygen therapy on the patient. In this pilot study, we explored the possibility of noninvasively detecting canine tissues optical properties by Time Domain Near-Infrared Spectroscopy (TD-NIRS) and then retrieving hemodynamic parameters (deoxygenated and oxygenated hemoglobin molar concentration and tissue oxygen saturation) on different tissues (Triceps Brachii, Biceps Femoralis and Head) of dogs. Four dogs with different hair length and color undergoing to hyperbaric chamber treatment were measured before and after the treatment, on each of the three sites and on both sides of the animal. In Triceps Brachii and Biceps Femoralis we found an increase in the absorption coefficient for both wavelengths after the treatment, meaning that the total concentration of blood has increased. Different results were obtained in the head, where the total hemoglobin concentration is decreased. The use of TD-NIRS oximetry technology seems a clinically feasible means to assess tissue oxygenation in most of dogs, thanks to a sufficiently high signal-to-noise ratio that allows to evaluate the optical parameters and consequently the physiological parameters of the area under investigation. Moreover, the presence of hair and dark skin did not prevent the possibility of obtaining robust readings

Genomic characterization and seroprevalence studies on alphaviruses in Uruguay

Alphaviruses (Togaviridae) are arboviruses frequently associated with emerging infectious diseases. In this study, we aimed to investigate the presence of alphaviruses in Uruguay by detecting the viral genome in mosquitoes and neutralizing antibodies in equines. A total of 3,575 mosquitoes were analyzed for alphavirus genome detection. Serologic studies were performed on 425 horse sera by plaque reduction neutralization test (PRNT80) against Venezuelan equine encephalitis virus (VEEV) subtype IAB, Pixuna virus (PIXV), Rio Negro virus (RNV), western equine encephalitis virus (WEEV), and Madariaga virus (MADV). Mosquitoes belonging to six genera were captured and 82.9% were identified as Culex pipiens. Two Cx. pipiens pools collected in Fray Bentos and Las Toscas localities were alphavirus positive, and phylogenetic analyses showed that the sequences grouped into two different clusters: the lineage I of eastern equine encephalitis virus and RNV (VEEV complex), respectively. Plaque reduction neutralization test assays showed antibodies against strains of the VEEV complex, MADV, and WEEV. Rio Negro virus was the most geographically widespread virus, showing higher seroprevalences (up to 20%). Seroprevalences against VEEV IAB ranged between 4.6% and 13%; antibodies against PIXV, WEEV, and MADV were less frequent (3–4%). In conclusion, RNV exhibited the highest seroprevalence in horses, a wide geographical distribution, and viral genome was detected in Cx. pipiens mosquitoes. Madariaga virus had a low seroprevalence in equines, but an epizootic lineage typical of North America was detected in Cx. pipiens mosquitoes. Taken together, our results show that alphaviruses are present in Uruguay with variable occurrence and geographical distribution being a potential threat for human and equine health

Assessment of power spectral density of microvascular hemodynamics in skeletal muscles at very low and low-frequency via near-infrared diffuse optical spectroscopies

In this work, we used a hybrid time domain near-infrared spectroscopy (TD-NIRS) and diffuse correlation spectroscopy (DCS) device to retrieve hemoglobin and blood flow oscillations of skeletal muscle microvasculature. We focused on very low (VLF) and low-frequency (LF) oscillations (i.e., frequency lower than 0.145 Hz), that are related to myogenic, neurogenic and endothelial activities. We measured power spectral density (PSD) of blood flow and hemoglobin concentration in four muscles (thenar eminence, plantar fascia, sternocleidomastoid and forearm) of 14 healthy volunteers to highlight possible differences in microvascular hemodynamic oscillations. We observed larger PSDs for blood flow compared to hemoglobin concentration, in particular in case of distal muscles (i.e., thenar eminence and plantar fascia). Finally, we compared the PSDs measured on the thenar eminence of healthy subjects with the ones measured on a septic patient in the intensive care unit: lower power in the endothelial-dependent frequency band, and larger power in the myogenic ones were observed in the septic patient, in accordance with previous works based on laser doppler flowmetry

Positive Selection Results in Frequent Reversible Amino Acid Replacements in the G Protein Gene of Human Respiratory Syncytial Virus

Human respiratory syncytial virus (HRSV) is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly temporal pattern of genetic variation, with a replacement of dominant genotypes occurring during consecutive years. In the present study we utilized phylogenetic methods to detect and map sites subject to adaptive evolution in the G protein of HRSVA and HRSVB. A total of 29 and 23 amino acid sites were found to be putatively positively selected in HRSVA and HRSVB, respectively. Several of these sites defined genotypes and lineages within genotypes in both groups, and correlated well with epitopes previously described in group A. Remarkably, 18 of these positively selected tended to revert in time to a previous codon state, producing a “flip-flop” phylogenetic pattern. Such frequent evolutionary reversals in HRSV are indicative of a combination of frequent positive selection, reflecting the changing immune status of the human population, and a limited repertoire of functionally viable amino acids at specific amino acid sites

VASCOVID: hybrid diffuse optical platform combined with a pulse-oximeter and an automatized inflatable tourniquet for the assessment of metabolism and endothelial health in the intensive care

VASCOVID project is developing and testing a hybrid diffuse optical monitor for evaluating endothelial function and metabolism in intensive care including COVID-19

Luigi Settembrini. Periodico letterario educativo mensile. A. 2, n.1(1892)-A. 3, n.10(1894)

A.2, n.1(nov.1892): G. Olivieri, Ad Antonio Bartolini, P. 1-2 ; G. Olivieri, Prospero Viani, P. 2-11; R. Sabbatini, Ancora Quom o Quum?, P. 11-2 ; Pensieri del Settembrini, P. 12-3 ; E. Perito, Ad nubem, P. 13; F. Lagrance, Dell’educazione fisica, p. 14-15 ; Cronaca dell’Istituto L. Settembrini, P. 15-6.A. 2, n. 2(dic. 1892): G. Lanzalone, La morale nell’arte, P. 17-23 ; B. ( dal Bibliografo), Per i libri di testo nelle scuole elementari, P. 23-5 ; V. Notari, In Gutembergium artis typograficae inventorem, P. 25; Progressi della navigazione aerea, P. 26-8 ; Pensieri del Settembrini, P. 28-9 ; Il nostro concorso, P. 29 ; G. Lanzalone, La prima pioggia d’autunno, P. 30-1A. 2, n.3(gen. 1893): Bonghi, Una lettera del Bonghi, P. 33-4 ; G. Lanzalone, Ancora della morale nell’arte, P. 34-8 ; Pensieri del Settembrini, P. 38-9 ; C. Arlìa, Buon dì e tre anguille, P. 39-41 ; G. Lanzalone , All’amico G. Olivieri , P. 42-3 ; P. Lioy, Bagni e villeggiature, P. 43-5.A. 2, n. 4(feb. 1893): C. A. Alemagna, Per la morale nell’arte, P. 49-55.A. 2, n. 5(mar. 1893): R. Sabbatini, L’epistola di Saffo a Faone, P. 65-6 ; G. Lanzalone, Il drammaturgo(caricatura), P. 66-7 ; G. Lanzalone, Ancora per la morale dell’arte, P. 67-70 ; F. De Falco, Un’altra lettera!, P. 71-2 ; Il Settembrini, Per una petizione al Parlamento, P. 72; E. Perito, A mia sorella morta, P. 73-4.A. 2, n.6(apr. 1893): Il Settembrini, Petizione al Parlamento, P. 81-3 ; C. Arlia, Noterelle filologiche, P. 84-5 ; G. Bigoni, Ricordi Picentini (2 sonetti), P. 85 ; C. A. Alemagna, Lettera con annotazioni, P. 86-90 ; V. Caputo, Il giuramento, P. 90-1 ; A. Buscaino Campo, Il piè fermo di Dante, P. 92-3.A.2, n.7(apr. 1893): G. Lanzalone, Professori e maestri, P. 97-9 ; il Settembrini, Petizione al Parlamento, P. 100-2 ; Lista delle adesioni, P. 102-4 ; Guido Bigoni, Domenica Rusticana, P. 105 ; Pensieri del Settembrini, P. 105-7 ; Dal Gazzettino d’oro, Utili varietà, P. 107-8 ; G. Lanzalone, Al maggiore Vincenzo Notari, P. 108 ; V. Notarius, Risposta, P. 109 ; F. Accinelli, La poesia della vita, P. 109-10.A. 2, n.8(giu. 1893): C. Arlìa, Noterelle filologiche, P. 113-16 ; Guido Bigoni, La quercia del Tasso, P. 116 ; G. Lanzalone, La ginnastica con la neve, P. 116-17 ; Luigi Settembrini, Una lettera inedita di L. Settembrini, P. 118-19 ; V. Notaro, In Ariostum, P. 119 ; L’arte di respirare, P. 120-21 ; F. De Falco, Il suicidio e la religione, P. 122-24.A.2, n.9/10(lug.-ago. 1893): R. Mariano, Ad un banchetto nunziale, P. 129-132 ; G. Lanzalone, A Cristoforo Colombo, P. 132-34 ; C. Arlìa, Note filologiche, P. 135-36 ; G. Olivieri, Il terzo libro della vita di G. Cristo, P. 136-39 ; F. Persico, La pace, P. 140-41 ; L. A. Villari, Cesare Dalbono, P. 141-45.A.2, n.11/12(sett.-ott. 1893): Luigi Settembrini, Una lettera inedita di L. Settembrini, P. 153-54 ; A. De Leo, Vite di illustri salernitani, P. 154-62 ; G. Franciosi, I sogni, P. 162-63 ; A. Frabasile, Bozzetti ellenici, P. 164-70 ; L. A. Villari , Errori Giudiziari, P. 171-75 ; G. Lanzalone, Verismo, P. 175-76.A.3,n.1/2 (nov.-dic. 1893): M. Giordano, La pubblica educazione e l’ateismo, P. 1-4 ; il Settembrini, Concorso, P. 4 ; Per una forca conservata in un museo, P. 5 ; G. Lanzalone, L’Ora presente, P. 5 ; C. Mariano Pilar, Silvio Spaventa, P. 6-19 ; C. Arlìa, Note filologiche, P. 20-1 ; G. Grammatica, Ideale, P. 22 ; G. Olivieri, Funesta rimembranza, P. 31-2 ; G. Olivieri, La notte della vigilia del Natale, P. 32.A.3, n.3/4(gen.-feb. 1894): G. Lanzalone, E la nostra petizione?, P. 33-5 ; Dall’albo di Luigi Antonio Villari, P. 36 ; G. Olivieri, Una visita inaspettata, P. 37-46 ; A. Frabasile, Alla signora G. P., P. 47 ; M. Giordano, Il Governo, i Municipi e l’istruzione religiosa, P. 48-53 ; G. Lanzalone, Esercizi militari, P. 53 ; C. Arlìa, Note filologiche, P. 54 ; G. Lanzalone, Un dubbio proposto al prof. Sabbadini, P. 54-5 ; G. L., Risultato del passato concorso e concorso nuovo, P. 55-6 ; R. Galdi, Epistola di Catullo ad Ortalo, P. 57.A.3, n.5/6(mar-apr 1894): G. Lanzalone, Dell’educazione nelle scuole classiche, P. 65-70 ; G. L., Un epigramma di Leone XIII, P. 70-1 ; V. Caputo, Vita di borso, P. 72-6 ; C. Arlìa, Note filologiche, P. 76-7 ; G. Lanzalone, Amore, P. 78 ; Aniello Gaeta, Dulcissime Rerum, P. 79-81 ; Francesco De Falco, La duchessa Ravaschieri e il dormitorio, P. 81-2 ; Carmine Zottoli, Risultato del passato concorso e concorso nuovo, P. 82-6.A.3, n. 7/8(mag. – giu 1894): C. Arlìa, Note filologiche, P. 97-8 ; G. Lanzalone, Per il 1°Maggio, P. 98-101 ; M. Giordano, La libertà d’insegnamento e di coscienza, P. 101-10 ; L. A. Villari, Il capitano Tim- Tim, P. 111- 15 ; C. A. Alemagna, L’opera recente di Herbert Spencer, P. 115-16 ; Nicc. Castagna, Sospiro, P. 116 ; G. Cuomo, Sovra un passo del carme “I Sepolcri”, P. 117-20.A.3, n.9(lug. 1894): Concorso nuovo, P. 125 ; C. Arlìa, Note filologiche, P. 126-27 ; Il manicomio dei genii, P. 127 ; G. Lanzalone, Elena, P. 128 ; Giovanni Cuomo, Nunzio del giorno, P. 128-29 ; Giovanni Manfredi, Ofelia, P. 129 ; G. Lanzalone, Da Anacreonte, P. 139.A.3, n.10(ago. 1894): R. Sabbadini, L’anno della nascita di Gasparino Barziza, P. 141-42 ; G. Lanzalone, Il Discredito dei versi, P. 142-46 ; C. Arlìa, Note filologiche, P. 147-48 ; E. Perito, L’ultima rosa d’estate, P. 148 ; D’Aloja, L’arte e la critica, P. 149-51 ; Epigrammi, P. 151-52