Abstract. The Catalogue, available at the Centre de Données Stellaires de Strasbourg , consists of 13 573 records concerning the results obtained from different methods for 7778 stars, reported in the literature. The following data are listed for each star: identifications, apparent magnitude, spectral type, apparent diameter in arcsec, absolute radius in solar units, method of determination, reference, remarks. Comments and statistics obtained from CADARS are given.

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Hyperventilation, and reduced cerebral blood flow velocity can occur in postural tachycardia syndrome (POTS). We studied orthostatically intolerant patients, with suspected POTS, with a chief complaint of upright dyspnea. Based on our observations of an immediate reduction of cerebral blood flow velocity with orthostasis, we hypothesize that the resulting ischemic hypoxia of the carotid body causes chemoreflex activation, hypocapnic hyperpnea, sympathetic activation, and increased heart rate and blood pressure in this subset of POTS. We compared 11 dyspneic POTS subjects to 10 healthy controls during a 70° head-up tilt. In POTS subjects during initial orthostasis prior to BP recovery; central blood volume and mean arterial pressure were reduced (P<0.025) resulting in a significant (P<0.001) decrease in cerebral blood flow velocity, which temporally preceded (17±6 s; P<0.025) a progressive increase in minute ventilation and decrease in end tidal CO2 (P<0.05), compared to controls. Sympathoexcitation, measured by muscle sympathetic nerve activity, was increased in POTS, (P<0.01), and inversely proportional to end tidal CO2 and resulted in an increase in heart rate, (P<0.001), total peripheral resistance (P<0.025), and a decrease in cardiac output (P<0.025). The decrease in cerebral blood flow velocity and mean arterial pressure during initial orthostasis was greater (P<0.025) in POTS. Our data suggest that exaggerated initial central hypovolemia during initial orthostatic hypotension in POTS results in reduced cerebral blood flow velocity and postural hypocapnic hyperpnea that perpetuates cerebral ischemia. We hypothesize that sustained hypocapnia and cerebral ischemia produce sympathoexcitation, tachycardia and a statistically significant increase in blood pressure.

We hypothesize upright cognitive impairment in Postural Tachycardia Syndrome is due to reduced cerebral blood flow. Cerebral blood flow velocity measured by transcranial Doppler ultrasound decreased excessively during 70° tilt in a minority of patients with intermittent hyperpnea/hypocapnia. Incremental tilt showed no difference in mean cerebral blood flow velocity. But, N-Back memory tasking indicated progressive compromised memory, reduced functional hyperemia and reduced neurovascular coupling. Orthostasis caused slow oscillations in cerebral blood flow velocity linked to oscillations in arterial pressure in Postural Tachycardia Syndrome. We also hypothesize that oscillatory cerebral blood flow velocity degrades neurovascular coupling. We performed 2-Back testing supine and during incremental tilts to 15°, 30°, 45° and 60° in 11 Postural Tachycardia Syndrome and 9 controls. Oscillatory arterial pressure, oscillatory cerebral blood flow velocity and neurovascular coupling were similar supine. Oscillatory arterial pressure increased 31, 45, 67, and 93% in Postural Tachycardia Syndrome during tilt, remaining unchanged in control. Oscillatory cerebral blood flow velocity increased by 61, 82, 161, and 264% in Postural Tachycardia Syndrome during tilt remaining unchanged in control. Functional hyperemia decreased from 4.1% to 3.0, 1.1, 0.2, to 0.04% in Postural Tachycardia Syndrome but was unchanged at 4% in control. Percent correct N-Back responses decreased from 78% to 33% in Postural Tachycardia Syndrome while remaining at 89% in controls. In Postural Tachycardia Syndrome, oscillatory cerebral blood flow velocity was linearly correlated with functional hyperemia (r2=0.76). Increased oscillatory cerebral blood flow is associated with reduced neurovascular coupling and diminished cognitive performance in Postural Tachycardia Syndrome.