Uremic frost in a critically ill patient

Polarization-Multiplexed Incoherent Broadband Surface Plasmon Resonance: A New Analytical Strategy for Plasmonic Sensing

Surface plasmon resonance (SPR) is an interfacial phenomenon, and the plasmonic sensors are based on the optical excitation of the collective oscillations of free electrons at a metal-dielectric interface. Here, we present the new development of an incoherent broadband (IBB)-SPR probe combining the wavelength interrogation technique with polarization-multiplexing (PM). The performance characteristics of the so-called PMIBB-SPR strategy was validated for the detection of nonenzymatic aqueous urea samples as a representative example for plasmonic sensing with an excellent wavelength and phase sensitivities of 0.1363 nm/mM and 10.34597 mM/deg, respectively. We further explored the missing link between plasmonic polariton resonance (PPR) and polarization modulation via the measurements of the Stokes parameters of the reflected light. This deepens our understanding of the fundamentals of polarization-multiplexed SPR phenomenon at the interface. This study thus paves the way to develop a new-generation analytical technique with the aim of tracking various real-time chemical and biological molecular interactions occurring at the interfaces.

Urea transporters and sweat response to uremia

In humans, urea is excreted in sweat, largely through the eccrine sweat gland. The urea concentration in human sweat is elevated when compared to blood urea nitrogen. The sweat urea nitrogen (UN) of patients with end-stage kidney disease (ESRD) is increased when compared with healthy humans. The ability to produce sweat is maintained in the overwhelming majority of ESRD patients. A comprehensive literature review found no reports of sweat UN neither in healthy rodents nor in rodent models of chronic kidney disease (CKD). Therefore, this study measured sweat UN concentrations in healthy and uremic rats. Uninephrectomy followed by renal artery ligation was used to remove 5/6 of renal function. Rats were then fed a high-protein diet to induce uremia. Pilocarpine was used to induce sweating. Sweat droplets were collected under oil. Sweat UN was measured with a urease assay. Serum UN was measured using a fluorescent ortho-pthalaldehyde reaction. Immunohistochemistry (IHC) was accomplished with a horseradish peroxidase and diaminobenzidine technique. Sweat UN in uremic rats was elevated greater than two times compared to healthy pair-fed controls (220 ± 17 and 91 ± 15 mmol/L, respectively). Post hoc analysis showed a significant difference between male and female uremic sweat UN (279 ± 38 and 177 ± 11 mmol/L, respectively.) IHC shows, for the first time, the presence of the urea transporters UT-B and UT-A2 in both healthy and uremic rat cutaneous structures. Future studies will use this model to elucidate how rat sweat UN and other solute excretion is altered by commonly prescribed diuretics.

Diagnosis of common dermopathies in dialysis patients: a review and update

Cutaneous abnormalities in patients with end-stage renal disease (ESRD) receiving hemodialysis or peritoneal dialysis may demonstrate signs of their underlying condition or reveal associated disease entities. While a thorough examination of the scalp, skin, mucosa, and nails is integral to establishing a diagnosis, certain conditions will resolve only with dialysis or improvement of their renal disease and others may not require or respond to treatment. Half and half nails, pruritus, xerosis, and cutaneous hyperpigmentation are common manifestations in ESRD. With hemodialysis, uremic frost is no longer prevalent in ESRD patients and ecchymoses have decreased in incidence. Acquired perforating dermatoses are seen in over one-tenth of hemodialysis patients. Metastatic calcinosis cutis and calciphylaxis are both rarely reported, although the latter is seen almost exclusively in the setting of hemodialysis. Diagnosis of nephrogenic systemic fibrosis has historically been challenging; as such, new diagnostic criteria have been proposed. Blood porphyrin profiles are needed to differentiate between porphyria cutanea tarda and pseudoporphyria. We will review and provide an update on the aforementioned common cutaneous manifestations of ESRD in patients receiving dialysis.