Detection and localization of calcium oxalate in kidney using synchrotron deep ultraviolet fluorescence microscopy

Renal oxalosis is a rare cause of renal failure whose diagnosis can be challenging. Synchrotron deep ultraviolet (UV) fluorescence was assayed to improve oxalosis detection on kidney biopsies spatial resolution and sensitivity compared with the Fourier transform infrared microspectroscopy gold standard. The fluorescence spectrum of synthetic mono-, di- and tri-hydrated calcium oxalate was investigated using a microspectrometer coupled to the synchrotron UV beamline DISCO, Synchrotron SOLEIL, France. The obtained spectra were used to detect oxalocalcic crystals in a case control study of 42 human kidney biopsies including 19 renal oxalosis due to primary (PHO, n = 11) and secondary hyperoxaluria (SHO, n = 8), seven samples from PHO patients who received combined kidney and liver transplants, and 16 controls. For all oxalocalcic hydrates samples, a fluorescence signal is detected at 420 nm. These spectra were used to identify standard oxalocalcic crystals in patients with PHO or SHO. They also revealed micrometric crystallites as well as non-aggregated oxalate accumulation in tubular cells. A nine-points histological score was established for the diagnosis of renal oxalosis with 100% specificity (76–100) and a 73% sensitivity (43–90). Oxalate tubular accumulation and higher histological score were correlated to lower estimated glomerular filtration rate and higher urinary oxalate over creatinine ratio.

Anisotropy of 3D Columnar Coatings in Mid-Infrared Spectral Range

Polarisation analysis in the mid-infrared fingerprint region was carried out on thin (∼1 μm) Si and SiO2 films evaporated via glancing angle deposition (GLAD) method at 70∘ to the normal. Synchrotron-based infrared microspectroscopic measurements were carried out on the Infrared Microspectroscopy (IRM) beamline at Australian Synchrotron. Specific absorption bands, particularly Si-O-Si stretching vibration, was found to follow the angular dependence of ∼cos2θ, consistent with the absorption anisotropy. This unexpected anisotropy stems from the enhanced absorption in nano-crevices, which have orientation following the cos2θ angular dependence as revealed by Fourier transforming the image of the surface of 3D columnar films and numerical modeling of light field enhancement by sub-wavelength nano-crevices.

Anisotropy of 3D Columnar Coatings in Mid-Infrared Spectral Range

Polarisation analysis in the mid-infrared fingerprint region was carried out on thin (∼1μm) Si and SiO2 films evaporated via glancing angle deposition (GLAD) method at 70∘ to the normal. Synchrotron-based infrared microspectroscopic measurements were carried out on the Infrared Microspectroscopy (IRM) beamline at Australian Synchrotron. Specific absorption bands, particularly Si-O-Si stretching vibration, was found to follow the angular dependence of ∼cos2θ, consistent with the absorption anisotropy. This unexpected anisotropy stems from the enhanced absorption in nano-crevices, which have orientation following the cos2θ angular dependence as revealed by Fourier transforming the image of the surface of 3D columnar films and numerical modeling of light field enhancement by sub-wavelength nano-crevices.

Plastic biodegradation: do Galleria mellonella larvae - bio-assimilate polyethylene? A spectral histology approach using isotopic labelling and infrared microspectroscopy.

Environmental pollution by non-biodegradable polyethylene (PE) plastics is of major concern, thus, organisms capable of bio-degrading PE are required. The larvae of the Greater Wax Moth, Galleria mellonella (Gm), were identified as a potential candidate to digest PE. In this study, we tested whether PE was metabolized by Gm larvae and could found in their tissues. We examined the implication of the larval gut microbiota by using conventional and axenic reared insects. First, our study showed that neither beeswax nor PE alone favour the growth of young larvae. We then used Fourier-Transform Infrared Microspectroscopy (microFTIR) to detect deuterium in larvae fed with isotopically labelled food. Perdeuterated molecules were found in most tissues of larvae fed with deuterium labelled oil for 72 hours proving that microFTIR can detect metabolization of 1-2 mg of deuterated food. No bio-assimilation was detected in the tissues of larvae fed with 1-5 mg of perdeuterated PED4 for 72 hours and 19-21 days, but micron sized PE particles were found in the larval digestive tract cavities. We evidenced weak bio-degradation of PE films in contact for 24 hours with the dissected gut of conventional larvae; and in the PED4 particles from excreted larval frass. Our study confirms that Gm larvae can bio-degrade PE but can not necessarily metabolize it.