It has been proposed that pre-diabetes may cause neuropathy. The aim of this study was to investigate whether cardiac autonomic neuropathy (CAN) in uraemic patients was related to the presence of ...pre-diabetes.
The study included 66 non-diabetic uraemic patients selected from a waiting list for kidney transplantation. They were on average 43 ± 12 years old, with a duration of uraemia of 32 ± 27 months in the pre-dialytic stage, or receiving either haemo-, or peritoneal dialysis. A control group of 14 healthy people matched by sex, age and body mass index were enrolled. Beat-to-beat variability was determined from the echocardiographic recording during deep inspiration and expiration. CAN was defined as a beat-to-beat value below 10 beats/min. Pre-diabetes was defined as presence of impaired fasting glucose and/or impaired glucose tolerance measured by oral glucose tolerance test (WHO/American Diabetes Association criteria 2007).
The prevalence of CAN was 38% in uraemic patients compared with 8% in the controls (p < 0.005). Twenty-seven (41%) out of the 66 uraemic patients were pre-diabetic, while the remaining 39 had a normal glucose tolerance. The prevalence of CAN was comparable in uraemic patients with (44%) and without (33%) pre-diabetes. Uraemic patients with CAN were characterised by higher systolic blood pressure (p < 0.05) and higher age (p < 0.005) compared with uraemic patients without CAN.
The prevalence of CAN and impaired glucose tolerance is high in uraemic patients, but impaired glucose tolerance seems to play no significant role in the aetiology of CAN in uraemic patients.
Nile Red is a benzo
phenoxazone dye containing a diethylamino substituent at the 9-position. In recent years, it has become a popular histological stain for cellular membranes and lipid droplets due ...to its unrivaled fluorescent properties in lipophilic environments. This makes it an attractive lead for chemical decoration to tweak its attributes and optimize it for more specialized microscopy techniques, e.g., fluorescence lifetime imaging or two-photon excited fluorescence microscopy, to which Nile Red has never been optimized. Herein, we present synthesis approaches to a series of monosubstituted Nile Red derivatives (9-diethylbenzo
phenoxazin-5-ones) starting from 1-naphthols or 1,3-naphthalenediols. The solvatochromic responsiveness of these fluorophores is reported with focus on how the substituents affect the absorption and emission spectra, luminosity, fluorescence lifetimes, and two-photon absorptivity. Several of the analogues emerge as strong candidates for reporting the polarity of their local environment. Specifically, the one- and two-photon excited fluorescence of Nile Red turns out to be very responsive to substitution, and the spectroscopic features can be finely tuned by judiciously introducing substituents of distinct electronic character at specific positions. This new toolkit of 9-diethylbenzo
phenoxazine-5-ones constitutes a step toward the next generation of optical molecular probes for advancing the understanding of lipid structures and cellular processes.
Chemical fine‐tuning of fluorophores is a pivotal step towards development of next generation fluorescent dyes for microscopy. With the advent of high‐resolution two‐photon excitation fluorescence ...imaging, there is a growing demand for very sensitive laser dyes that can be efficiently excited using commercial Ti:sapphire laser sources in the first near‐infrared window (NIR‐I, 780–1020 nm). Using the fluorescent dye Nile Red as the lead structure, we report a robust and concise Suzuki coupling approach for the synthesis of 14 new Nile Red analogues that feature extended π ring systems and diverse functionalities. For this set, we gauged their two‐photon excitation efficiency in NIR‐I as well as evaluated their general fluorescent properties (emission wavelength, Stokes shift, quantum yield and solvatochromism). Several of the new fluorophores were found to display very favorable characteristics. In particular, the derivative featuring a 4‐aminophenyl group in the 2‐position of Nile Red exhibited extreme solvent sensitivity, and the thien‐2‐yl substituted Nile Red derivative showed significantly redshifted emission, large Stokes shift and high two‐photon brightness.
A series of 14 Nile Red analogues with (hetero)aryl substituents at the 2‐ or 3‐positions were synthesized from convenient Suzuki couplings. Two‐photon excitation efficiency and general fluorescent properties were evaluated. A 4‐aminophenyl group resulted in extreme solvent sensitivity, and a thien‐2‐yl group led to significantly redshifted emission, large Stokes shift and high two‐photon brightness.
