Several studies indicate that low level laser therapy (LLLT) accelerates the healing process, however, for a determined
pathology, dosimetry remains difficult to be established. To understand the tissue optical properties under different
conditions is extremely relevant since the dose delivered to the target tissue is known to be critical. The skin
pigmentation influence on the laser attenuation is not yet well established on different mice lineages or human ethnical
groups, making the dose problematic. Along the same line, inflammatory processes may cause similar problems since the
tissues in this condition change their optical properties due to inflammatory cell accumulation. This work evaluated the
attenuation pattern of a HeNe laser (λ=632.8 nm) using ex vivo skin samples from Balb/C and C57BL/6 mice under
inflammatory stages induced in their paw by local carrageenan inoculation. The samples were placed between two
microscope slides, and a CCD camera was placed orthogonal to the beam path. The intensity distribution of the scattered
light was photographed in grayscale and analyzed by ImageJ software. Our findings suggest that even slight differences
of the epithelial pigmentation could result in a relevant dose loss delivered to the deeper tissues. The increase of the
inflammatory cell density in the connective tissue indicated a highly scattering area also resulting in a dose loss for the
deeper tissues when compared to control group.
Candida albicans is the most frequent human opportunistic pathogenic fungus and one of the most important causes of
nosocomial infections. In fact, diagnosis of invasive candidiasis presents unique problems. The aim of this work was to
evaluate, by fluorescence image analysis, cellular labeling of C. albicans with CdTe/CdS quantum dots conjugated or
not to concanavalin A (ConA). Yeast cells were incubated with CdTe/CdS quantum dots (QD) stabilized with
mercaptopropionic acid (MPA) (emission peak at 530 nm) for 1 hour. In the overall study we observed no morphological
alterations. The fluorescence microscopic analysis of the yeast cells showed that the non-functionalized QDs do not label
C. albicans cells, while for the QD conjugated to ConA the cells showed a fluorescence profile indicating that the
membrane was preferentially marked. This profile was expected since Concanavalin A is a protein that binds specifically
to terminal carbohydrate residues at the membrane cell surface. The results suggest that the QD-labeled Candida cells
represent a promising tool to open new possibilities for a precise evaluation of fungal infections in pathological
conditions.
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