Pressor responsiveness, hemodynamics and plasma renin activity in essential hypertension

Repurposing an adenine riboswitch into a fluorogenic imaging and sensing tag

Fluorogenic RNA aptamers are used to genetically encode fluorescent RNA and to construct RNA-based metabolite sensors. Unlike naturally occurring aptamers that efficiently fold and undergo metabolite-induced conformational changes, fluorogenic aptamers can exhibit poor folding, which limits their cellular fluorescence. To overcome this, we evolved a naturally occurring well-folded adenine riboswitch into a fluorogenic aptamer. We generated a library of roughly 10¹⁵ adenine aptamer-like RNAs in which the adenine-binding pocket was randomized for both size and sequence, and selected Squash, which binds and activates the fluorescence of green fluorescent protein-like fluorophores. Squash exhibits markedly improved in-cell folding and highly efficient metabolite-dependent folding when fused to a S-adenosylmethionine (SAM)-binding aptamer. A Squash-based ratiometric sensor achieved quantitative SAM measurements, revealed cell-to-cell heterogeneity in SAM levels and revealed metabolic origins of SAM. These studies show that the efficient folding of naturally occurring aptamers can be exploited to engineer well-folded cell-compatible fluorogenic aptamers and devices.

Systemic hemodynamics during sleep in young or middle-aged and elderly patients with essential hypertension

Age-related changes in cardiovascular regulatory mechanisms may affect blood pressure homeostasis during sleep and in the daytime. This study compared systemic hemodynamics during the daytime and sleep between 12 young or middle-aged patients (young, 42.1 +/- 13.9 years old, mean +/- SD, less than 56 years old) and 12 elderly patients with essential hypertension (old, 65.3 +/- 2.8, 60 to 70 years old). They were all hospitalized and placed on a diet containing approximately 7 g sodium chloride per day. Intra-arterial blood pressure and electrocardiogram were recorded for 24 hours, and electroencephalogram and electroophthalmogram were recorded during the night with a telemetric method. Cardiac output was measured with patients in the supine position by the cuvette method during the daytime and stage 3 or 4 sleep at night. The averaged 24-hour blood pressure was similar in the two groups (140 +/- 2 [SEM]/85 +/- 3 mm Hg in the young group and 144 +/- 4/81 +/- 2 mm Hg in the old group). The reduction in mean blood pressure during sleep was also comparable in both groups (-18 +/- 2 in the young group and -20 +/- 2 mm Hg in the old group). Cardiac index was smaller in the old group than the young group during both the daytime and sleep (daytime, 2.3 +/- 0.1 versus 3.2 +/- 0.2 [L/min]/m2, P < .01; sleep, 2.1 +/- 0.1 versus 2.6 +/- 0.2 [L/min]/m2, P < .01). The reduction in cardiac index during sleep was greater in the young than the old group (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)