Adaptative mechanism of the equilibrative nucleoside transporter 1 (ENT-1) and blood adenosine levels in elite freedivers.

PURPOSE: Long static or intense dynamic apnoea-like high-altitude exposure is inducing hypoxia. Adenosine is known to participate to the adaptive response to hypoxia leading to the control of heart rate, blood pressure and vasodilation. Extracellular adenosine level is controlled through the equilibrative nucleoside transporter 1 (ENT-1) and the enzyme adenosine deaminase (ADA). The aim of this study was to determine the control of adenosine blood level (ABL) via ENT-1 and ADA during apnoea-induced hypoxia in elite freedivers was similar to high-altitude adaptation. METHODS: Ten freediver champions and ten controls were studied. Biological (e.g. ENT-1, ADA, ABL, PaO2, PaCO2 and pH) and cardiovascular (e.g. heart rate, arterial pressure) parameters were measured at rest and after a submaximal dry static apnoea. RESULTS: In freedivers, ABL was higher than in control participants in basal condition and increased more in response to apnoea. Also, freedivers showed an ADA increased in response to apnoea. Finally, ENT-1 level and function were reduced for the free divers. CONCLUSION: Our results suggest in freedivers the presence of an adaptive mechanism similar to the one observed in human exposed to chronic hypoxia induced by high-altitude environment.

[Pulmonary histoplasmosis in an immunocompetent patient]. / Histoplasmose pulmonaire chez un patient immunocompétent avec nodules pulmonaires multiples évoluant vers la nécrose.

INTRODUCTION: Acute pulmonary histoplasmosis (APH) is rare in an immunocompetent patient. We report a case of APH diagnosed by culture of broncho-alveolar lavage (BAL) in a patient presenting a pseudo-tumoral form with nodules progressing to cavitation. OBSERVATION: A 41 year-old male smoker was hospitalized with a persistent fever, dry cough and dyspnoea on exertion. The first CT scan showed a reticulo-nodular interstitial infiltrate with lymphadenopathy that progressed rapidly to multiple pulmonary nodules with central cavitation. Bronchial endoscopy, with BAL culture, provided the diagnosis of Histoplasma capsulatum, variety capsulatum. The infection may have occurred during work in a hangar in Guadeloupe that was scattered with bats' guano. After two months of treatment by itraconazole, the patient's condition improved clinically and radiologically with reduction of the nodules and their cavitation. CONCLUSION: This case presents an immunocompetent patient with pulmonary histoplasmosis and multiple, radiologically atypical, nodules. The diagnosis was established by BAL culture.