Association of daytime napping with incidence of chronic kidney disease and end-stage kidney disease: A prospective observational study.

BACKGROUND AND AIMS: Few studies have examined the relationship between daytime napping and risk of kidney diseases. We aimed to investigate the association of daytime napping with the incidence of chronic kidney disease (CKD) and end-stage kidney disease (ESKD). We also examined whether sleep duration modified the association of nap with CKD or ESKD. METHODS: We recruited 460,571 European middle- to older-aged adults without prior CKD or ESKD between March 13, 2006, and October 1, 2010, in the UK Biobank. Sleep behavior data were obtained through questionnaires administered during recruitment. The analysis of the relationship between napping and the occurrence of CKD and ESKD utilized Cox proportional hazards regression models. The modification role of sleep duration on the effect of nap on CKD and ESKD was also examined. RESULTS: After a mean follow-up of 11.1 (standard deviation 2.2) years, we observed 28,330 incident CKD cases and 927 ESKD cases. The daytime napping was associated with incident CKD (P for trend = .004). After fully adjusted, when compared with participants who did not take nap, those in sometimes and usually nap groups had higher risk of CKD. Nevertheless, the available evidence did not support a link between daytime napping and ESKD (P for trend = .06). Simultaneously, there was insufficient evidence suggesting that sleeping duration modified the association of daytime napping with incident CKD or ESKD. CONCLUSION: Daytime napping was associated with an increased risk of CKD. However, the absence of conclusive evidence did not indicate a connection between daytime napping and ESKD.

Prostaglandin E2 receptor EP2 mediates the effect of cyclooxygenase 2 on secondary parathyroid hyperplasia in end-stage renal disease.

BACKGROUND: Secondary hyperparathyroidism (SHPT) in patients with end-stage renal disease (ESRD) is characterized by hyperplasia of the parathyroid glands (PTGs), while the underlying mechanism is not completely understood. Previously we demonstrated a relationship between cyclooxygenase 2 (COX2) overexpression and parathyroid hyperplasia and here we investigate the role of COX2 downstream metabolic product prostaglandin E2 (PGE2) and its receptor EP2 in the pathogenesis of SHPT. METHODS: PTGs isolated from ESRD patients with advanced SHPT were used to test the expression of COX2-microsomal prostaglandin E synthase-1 (mPGES-1)-EP2 pathway. A diffuse proliferative section of the PTGs was used for tissue culture and treated with high phosphate (HPi) medium, COX2-PGE2-EP2 pathway inhibitors or agonists. EP2 short hairpin RNA (shRNA) lentivirus was locally applied to treat an SHPT rat model. RESULTS: In PTGs isolated from ESRD patients, enhanced immunoactivities of COX2, mPGES-1 and EP2 were observed. In primary cultured PTG tissues, HPi induced intact parathyroid hormone (iPTH) secretion, proliferating cell nuclear antigen (PCNA) expression and COX2 activity, while COX2 and EP2 inhibitors attenuated hyperparathyroidism promoted by HPi. Furthermore, PGE2 or EP2 agonist (butaprost) directly stimulated hyperparathyroidism, whereas EP2 receptor antagonist or cyclic adenosine monophosphate inhibitor attenuated the hyperparathyroidism promoted by PGE2 or butaprost. EP2 shRNA treatment significantly reduced excessive expressions of EP2 and PCNA in the PTGs of nephrectomy rats fed an HPi diet, diminished the size of PTGs and downregulated serum iPTH levels. CONCLUSIONS: The COX2 downstream PGE2 and its receptor EP2 may play an important role in HPi-induced parathyroid hyperplasia and may serve as a potential therapeutic target for SHPT in ESRD.

NF-κB activation contributes to parathyroid cell proliferation in chronic kidney disease.

BACKGROUND: Secondary hyperparathyroidism is characterized by parathyroid gland (PG) hyperplasia, and excessive synthesis and secretion of parathyroid hormone (PTH). Reduced vitamin D receptor (VDR) density has shown to play an essential role in PG hyperplasia progression; nevertheless, its exact mechanism remains unclear. VDR has shown to suppress the inflammation mediator NF-κB-mediated gene transcription. The aim of this study is to examine whether NF-κB is involved in the pathogenesis of parathyroid hyperplasia. METHODS: 35 PGs was obtained from 10 maintenance hemodialysis patients who underwent parathyroidectomy surgery. 5/6-nephrectomized rats fed with a high-phosphate diet were divided into four groups: (1) Nx + vehicle group, treated with vehicle; (2) Nx + PDTC prevention group, treated with NF-κB inhibitor PDTC for 2 months; (3) Nx + PDTC therapy group, treated with PDTC for 1 month; (4) Nx + calcitriol group, treated with activated vitamin D calcitriol for 1 month. Ten sham-operated rats fed with normal-phosphate diet were used as a control group. Serum calcium, phosphorus, creatinine, Blood urea nitrogen (BUN), intact PTH and PG size in rats were measured. Proliferating cell nuclear antigen (PCNA), VDR, NF-κB of PGs were examined using immunohistochemistry and western blot. RESULTS: The activation of NF-κB pathway in the nodular hyperplasia gland was significantly increased compared with the diffuse hyperplasia gland found in hemodialysis patients. Markedly higher serum creatinine, BUN, phosphorus levels, serum iPTH levels and larger PGs were found in Nx rats fed with a high-phosphate diet compared to sham-operated rats. Also, PCNA levels and activation of NF-κB pathway in PGs were higher compared with the sham group, meanwhile the VDR levels decreased. Contrary, treating rats with PDTC and calcitriol notably reduced serum iPTH, expression of PCNA and activation of NF-κB pathway, and decreased the enlargement of PGs in those animals. CONCLUSIONS: NF-κB plays an important role in PG hyperplasia progression. VDR deficiency may be involved in the parathyroid gland hyperplasia through the activation of NF-κB pathway.

The 4051-Angstroms band of C3 (A 1Piu-X 1Sigmag +, 000-000): perturbed low-J lines and lifetime measurements.

Rotational analyses have been carried out at high resolution for the 000-000 and 000-100 bands of the A (1)Pi(u)-X (1)Sigma(g) (+) transition of supersonic jet-cooled C(3). Two different spectra have been recorded for each band, using time gatings of 20-150 and 800-2300 ns. At the shorter time delay the spectra show only the lines observed by many previous workers. At the longer time delay many extra lines appear, some of which have been observed previously by [McCall et al.Chem. Phys. Lett. 374, 583 (2003)] in cavity ring-down spectra of jet-cooled C(3). Detailed analysis of these extra lines shows that at least two long-lived states perturb the A (1)Pi(u), 000 state. One of these appears to be a (3)Sigma(u) (-) vibronic state, which may possibly be a high vibrational level of the b (3)Pi(g) state, and the other appears to be a P = 1 state with a low rotational constant B. Our spectra also confirm the reassignment by McCall et al. of the R(0) line of the 000-000 band, which is consistent with the spectra recorded towards a number of stars that indicate the presence of C(3) in the interstellar medium. Fluorescence lifetimes have been measured for a number of upper-state rotational levels. The rotational levels of the A (1)Pi(u) state have lifetimes in the range of 230-190 ns, decreasing slightly with J; the levels of the perturbing states have much longer lifetimes, with some of them showing biexponential decays. An improved value has been obtained for the nu(1) vibrational frequency of the ground state, nu(1) = 1224.4933 +/- 0.0029 cm(-1).

Inkjet printing of nanosized silver colloids.

A water-based conducting ink, composed of well dispersed nano-silver particles, has been successfully inkjet printed using an ordinary commercial printer. The silver colloids with diameter around 50 nm were dispersed in a water and diethylene glycol cosolvent system. The 25 wt% silver ink had a viscosity of about 7.4 cP and surface tension of 33.5 dyn cm(-1) at 20 degrees C, which is appropriate for printing jobs. Continuous and smooth lines of 130 microm width could be printed on ordinary glass substrates using an Epson R210 printer. After baking at 260 degrees C for 3 min, these lines exhibited a resistivity of 1.6 x 10(-5) Omega cm, which could serve as conducting lines for electronic applications.