To compare circulating pigment epithelium derived factor (PEDF)
levels in type 2 diabetes patients (T2D) with and without
metabolic syndrome (MetS+/-) to healthy controls and assess
PEDF association with plasminogen activator inhibitor-1 (PAI-1)
and von Willebrand factor (vWF) as markers of endothelial
dysfunction. Fifty T2D individuals and forty healthy controls were
included. PEDF, PAI-1, vWF, anthropological parameters, lipids,
and markers of insulin resistance were investigated in all
subjects. Compared to controls only MetS+ diabetics had higher
PEDF levels [14.2 (10.2-16.0) mg/l vs. 11.1 (8.6-14.4) mg/l;
p<0.05]. PEDF significantly correlated: positively with body mass
index (ρ=0.25), smoking (ρ=0.21), C-reactive protein (ρ=0.22),
triglycerides (ρ=0.38), non-HDL-cholesterol (ρ=0.39),
apolipoprotein B (ρ=0.38), fasting glucose (ρ=0.22), glycated
hemoglobin (ρ=0.24), C-peptide (ρ=0.28), insulin (ρ=0.26); and
negatively with HDL-cholesterol (ρ=-0.42) and apolipoprotein A1
(ρ=-0.27). Independent association of PEDF with vWF in
T2DMetS- subjects was found. Significantly elevated PEDF in
T2DMet+ patients and its association with adverse metabolic
profile confirmed PEDF as a marker of insulin resistance.
Negative independent association of PEDF with vWF in T2DMetSpatients may reveal its angio-protective role.
Chlorophyll (Chl) a fluorescence measurements as evaluators of plant freezing tolerance are frequently insufficiently sensitive to detect the early metabolic changes that are initiated following exposure to freezing temperatures. Using cold-acclimated winter wheat, I analysed the polyphasic transience (from 50 µs to 1 s) of Chl a fluorescence. This enabled detailed studies of the progressive energy flows and efficiencies within the photosystem 2 (PS2) complex that ensue following initial exposure to freezing temperatures right through to the plant recovery stage. The initial consequences of mild frosts that may cause primary damage involve a disturbance to the energy transfer subsequent to QA (the primary quinone electron acceptor of PS2). Lower freezing temperatures, on the other hand, may deter energy flow between the PS2 reaction centre (RC), Chl, and QA. All primary damage could only be repaired partially. Further freezing-triggered dysfunction of the electron transfer between the PS2 RCs and QA was connected with secondary damage that could lead to PS2 deactivation. Both primary and secondary freezing damages were reflected in decreased PIABS, the Performance Index based on equal absorption that characterizes all energy bifurcations in PS2. PIABS also differentiated cultivars with contrasting freezing-tolerance either subsequent to the onset of freezing or during the recovery stage. In contrast, the potential quantum yield of PS2 (Fv/Fm), which characterizes efficiency of energy trapping in the PS2 RCs, was only different in cultivars with contrasting freezing-tolerance during the recovery stage.