Right-to-left shunt with hypoxemia in pulmonary hypertension

<p>Abstract</p> <p>Background</p> <p>Hypoxemia is common in pulmonary hypertension (PH) and may be partly related to ventilation/perfusion mismatch, low diffusion capacity, low cardiac output, and/or right-to-left (RL) shunting.</p> <p>Methods</p> <p>To determine whether true RL shunting causing hypoxemia is caused by intracardiac shunting, as classically considered, a retrospective single center study was conducted in consecutive patients with precapillary PH, with hypoxemia at rest (PaO₂< 10 kPa), shunt fraction (Qs/Qt) greater than 5%, elevated alveolar-arterial difference of PO₂(AaPO₂), and with transthoracic contrast echocardiography performed within 3 months.</p> <p>Results</p> <p>Among 263 patients with precapillary PH, 34 patients were included: pulmonary arterial hypertension, 21%; PH associated with lung disease, 47% (chronic obstructive pulmonary disease, 23%; interstitial lung disease, 9%; other, 15%); chronic thromboembolic PH, 26%; miscellaneous causes, 6%. Mean pulmonary artery pressure, cardiac index, and pulmonary vascular resistance were 45.8 ± 10.8 mmHg, 2.2 ± 0.6 L/min/m², and 469 ± 275 dyn.s.cm^-5, respectively. PaO₂in room air was 6.8 ± 1.3 kPa. Qs/Qt was 10.2 ± 4.2%. AaPO₂under 100% oxygen was 32.5 ± 12.4 kPa. Positive contrast was present at transthoracic contrast echocardiography in 6/34 (18%) of patients, including only 4/34 (12%) with intracardiac RL shunting. Qs/Qt did not correlate with hemodynamic parameters. Patients' characteristics did not differ according to the result of contrast echocardiography.</p> <p>Conclusion</p> <p>When present in patients with precapillary PH, RL shunting is usually not related to reopening of patent <it>foramen ovale</it>, whatever the etiology of PH.</p

Experimental shift of diet and DIC stable carbon isotopes: influence on shell δ13C values in the Manila clam Ruditapes philippinarum

International audienceThe influences of diet and seawater dissolved inorganic carbon (DIC) on the carbon isotope composition of shell aragonite (δ13Cshell) in the Manila clam Ruditapes philippinarum reared under laboratory conditions were investigated. Clams were exposed to two successive negative carbon isotope shifts: a first shift in diet (δ13Cphytoplankton) and a second shift, 35 days later, in DIC (δ13CDIC). Both successive shifts induced a decrease in δ13Cshell. These results are the first to experimentally confirm an incorporation of respired carbon derived from food and carbon from DIC into shell carbonate of adult bivalves. Skeletal δ13C responded to changes in the δ13C of both diet and DIC in less than 7 days. Consequently, proxies based on δ13Cshell may be used with high temporal resolution. Using δ13Cphytoplankton as a proxy for the carbon isotope composition of respired carbon (δ13CR) resulted in a rather constant percentage of metabolic carbon (CM) into the shell carbonate over time (close to 12%). However, an accurate estimation of δ13CR is required in order to precisely estimate the percentage of metabolic carbon incorporated into the shell. Despite the significant incorporation of metabolic carbon into shell carbonate, our experimental results revealed that δ13Cshell was highly correlated with δ13CDIC (r² = 0.77, p < 0.0001). Thus it seems that δ13Cshell is a promising proxy of large scale variations in δ13CDIC and therefore of salinity in estuarine water

Enhancing Long-Term Device Stability Using Thin Film Blends of Small Molecule Semiconductors and Insulating Polymers to Trap Surface-Induced Polymorphs

The lack of long-term stability in thin films of organic semiconductors can often be caused by the low structural stability of metastable phases that are frequently formed upon deposition on a substrate surface. Here, thin films of 2,7-dioctyloxy[1]benzothieno[3,2-b]benzothiophene (C8O-BTBT-OC8) and blends of this material with polystyrene by solution shearing are fabricated. Both types of films exhibit the metastable surface-induced herringbone phase (SIP) in all the tested coating conditions. The blended films reveal a higher device performance with a field-effect mobility close to 1 cm2 V−1 s−1, a threshold voltage close to 0 V, and an on/off current ratio above 107. In situ lattice phonon Raman microscopy is used to study the stability of the SIP polymorph. It is found that films based on only C8O-BTBT-OC8 slowly evolve to the Bulk cofacial phase, significantly impacting device electrical performance. In contrast, the blended films stabilize the SIP phase, leading to devices that maintain a high performance over 1.5 years. This work demonstrates that blending small-molecule organic semiconductors with insulating binding polymers can trap metastable polymorphs, which can lead to devices with both improved performance and long-term stability.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Opacidades em vidro fosco nas doenças pulmonares difusas: correlação da tomografia computadorizada de alta resolução com a anatomopatologia Ground-glass opacity in diffuse lung diseases: high-resolution computed tomography-pathology correlation

Opacidade em vidro fosco é achado freqüentemente visto na tomografia computadorizada de alta resolução do tórax e se traduz pelo aumento do coeficiente de atenuação dos pulmões, mas sem apagar as marcas broncovasculares. Por sua inespecificidade, a associação com outros achados radiológicos, clínicos e anatomopatológicos deve ser considerada para uma interpretação diagnóstica mais correta. Neste trabalho foram analisados 62 exames tomográficos de pacientes com doenças pulmonares difusas, de 14 etiologias diferentes, em que opacidades em vidro fosco foram o achado único ou predominante, e feita correlação anatomopatológica por meio de biópsias ou necropsias. Na pneumocistose as opacidades em vidro fosco corresponderam, histologicamente, à ocupação alveolar por material espumoso contendo parasitos; no carcinoma bronquíolo-alveolar, a espessamento dos septos alveolares e ocupação de sua luz por muco e células tumorais; na paracoccidioidomicose, a espessamento dos septos alveolares, áreas de fibrose e alvéolos contendo exsudato broncopneumônico; na sarcoidose, a fibrose ou a acúmulo de granulomas; na fibrose pulmonar idiopática, a espessamento dos septos alveolares por fibrose; na bronquiolite obliterante com pneumonia em organização, a pneumonia intersticial com áreas de organização intra-alveolar. A ocupação alveolar por sangue foi observada nos casos de leptospirose, hemossiderose idiopática, metástases de tumor renal e na aspergilose invasiva; por vacúolos de gordura na pneumonia lipídica; por material protéico e lipoprotéico na silicoproteinose e na proteinose alveolar; e por líquido de edema na insuficiência cardíaca congestiva.<br>Ground-glass opacity is a finding frequently seen in high-resolution computed tomography examinations of the chest and is characterized by hazy increased attenuation of lung, however without blurring of bronchial and vascular margins. Due to its unspecificity, association with other radiological, clinical and pathological findings must be considered for an accurate diagnostic interpretation. In this paper were reviewed 62 computed tomography examinations of patients with diffuse pulmonary diseases of 14 different etiologies in which ground-glass opacity was the only or the most remarkable finding, and correlated this findings with pathology abnormalities seen on specimens obtained from biopsies or necropsies. In pneumocystosis, ground-glass opacities correlated histologically with alveolar occupation by a foaming material containing parasites, in bronchioloalveolar cell carcinoma with thickening of the alveolar septa and occupation of the lumen by mucus and tumoral cells, in paracoccidioidomycosis with thickening of the alveolar septa, areas of fibrosis and alveolar bronchopneumonic exsudate, in sarcoidosis with fibrosis or clustering of granulomas and in idiopathic pulmonary fibrosis with alveolar septa thickening due to fibrosis. Alveolar occupation by blood was found in cases of leptospirosis, idiopathic hemosiderosis, metastatic kidney tumor and invasive aspergillosis whereas oily vacuoli were seen in lipoid pneumonia, proteinaceus and lipoproteinaceus material in silicoproteinosis and pulmonary alveolar proteinosis, and edematous fluid in cardiac failure