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In recent years a northward expansion of Sardinella aurita has been reported in the western Mediterranean. Considering the coexistence of its larvae with those of the dominant species Engraulis encrasicolus, the present study was conducted to compare their vertical distributions in 2 areas off the Catalan coast with different vertical environmental conditions. During summer, the water column was stratified with a deep chlorophyll maximum (DCM) beneath the pycnocline. However, the southern area, under the influence of the Ebro River, was characterized by a secondary surface chlorophyll maximum. Vertical distribution of larval food, nauplii and copepodites showed good agreement with the high chlorophyll layers. In the earliest stages of development, larvae of both species remained in the upper levels. From 6 mm standard length on they developed a day/night migratory behaviour to search for food during the day (feeding period). Therefore, in the south, where the abundance of potential food in the upper layers was relatively high, larvae of both species remained in the upper levels during the day. However, in the north, where food was restricted to the DCM, only E. encrasicolus larvae were able to reach these deep levels. The low temperatures (~15°C) detected at the DCM may restrict the vertical migration of S. aurita in accordance with their thermophilic character. This limitation might represent a restriction for the northward expansion of this species in the western Mediterranean.

We hypothesized that chronic oral administration of the phosphodiesterase-5 inhibitor sildenafil could improve the exercise capacity and pulmonary hemodynamics in patients with pulmonary arterial hypertension (PAH) on the basis of previous short-term studies. We tested this hypothesis in 14 subjects with PAH, including seven patients with the idiopathic form and seven patients with atrial septal defects, but no other congenital heart abnormalities. Patients were subjected to a 6-min walk test and dyspnea was graded according to the Borg scale. Pulmonary flow and pressures were measured by Doppler echocardiography. Patients were given sildenafil, 75 mg orally three times a day, and followed up for 1 year. Sildenafil therapy resulted in the following changes: increase in the 6-min walk distance from a median value of 387 m (range 0 to 484 m) to 462 m (range 408 to 588 m; P < 0.01), improvement of the Borg dyspnea score from 4.0 (median value) to 3.0 (P < 0.01), and increased pulmonary flow (velocity-time integral) from a median value of 0.12 (range 0.08 to 0.25) to 0.23 (range 0.11 to 0.40; P < 0.01) with no changes in pulmonary pressures. In one patient with pulmonary veno-occlusive disease diagnosed by a lung biopsy, sildenafil had a better effect on the pulmonary wedge pressure than inhaled nitric oxide (15 and 29 mmHg, respectively, acute test). He walked 112 m at baseline and 408 m at one year. One patient died at 11 months of treatment. No other relevant events occurred. Thus, chronic administration of sildenafil improves the physical capacity of PAH patients and may be beneficial in selected cases of veno-occlusive disease.

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