Laser induced autofluorescence studies of animal skin used in modeling of human cutaneous tissue spectroscopic measurements

BACKGROUND/PURPOSE: Laser-induced autofluorescence spectroscopy provides excellent possibilities for medical diagnostics of different tissue pathologies including cancer. However, to create the whole picture of pathological changes, investigators collect spectral information from patients in vivo or they study different tumor models to obtain objective information for fluorescent properties of every kind of healthy and diseased tissue. Therefore, it is very important to find the most appropriate, and close to the human skin, animal samples from the fluorescence point of view, which will allow the extrapolation of the animal data to human spectroscopic diagnostics. METHODS: In the present work, we examined the autofluorescence properties of different animal skin tissues, which are considered as the most common skin models. A nitrogen laser was used as an excitation source. Samples of healthy mouse, chicken and pig skin in vivo and/or ex vivo were studied and were compared with results obtained from investigations of healthy human skin in vivo. RESULTS AND CONCLUSION: Specific features of the recorded spectra are discussed and the possible origin of the obtained fluorescence signals is proposed. Quantitative evaluation of data extrapolation for each skin type is also depicted.     

A Complication of Stellate Ganglion Block?

Abstract: Stellate ganglion block is commonly used to treat the sympathetically maintained pain which may occur in one‐third of patients with complex regional pain syndrome type 1. A complication that followed a single block and presented a diagnostic dilemma for the ophthalmologist is reported.     

Circulating adipocytokines in non-diabetic and Type 1 diabetic children: relationship to insulin therapy, glycaemic control and pubertal development.

AIM: To determine the influence of Type 1 diabetes mellitus on circulating adipocytokines in children. METHODS: The circulating concentrations of leptin, adiponectin, resistin and tumour necrosis factor (TNF)-alpha were measured in 91 children, aged 11.1 +/- 2.7 years, with Type 1 diabetes mellitus (T1DM). Ninety-one healthy children were selected as control subjects. RESULTS: Body mass index-adjusted leptin concentrations were higher in the pubertal diabetic children compared with the control children. There was a significant positive correlation between leptin and daily insulin dose in the diabetic group. Circulating adiponectin concentrations were higher in the prepubertal diabetic children and were positively associated with HbA(1c). Resistin concentrations were lower in the prepubertal non-diabetic subjects compared with the pubertal non-diabetic children, whose values were higher than those of the diabetic children. TNF-alpha concentrations were similar in non-diabetic and diabetic children. CONCLUSIONS: Circulating concentrations of adipocytokines are abnormal in Type 1 diabetic children, although the direction of change differs by cytokine. Pubertal development, in addition to insulin treatment and glycaemic control, also influences the concentrations.     

Non-invasive temperature imaging of muscles with magnetic resonance imaging using spin-echo sequences

The application of spin-echo magnetic resonance imaging sequences on non-invasive temperature imaging for temperature mapping of human limbs is investigated. In an in vitro expriment performed on a meat sample, the equilibrium magnetisation P and the spin-lattice relaxation time T₁ are calculated from the values for the repetition time TR and the signal intensities obtained by a spin-echo sequence at different tissue temperatures tures as measured by a fibre-optic probe. T₁ is linearly correlated to the tissue temperature, and P is linearly correlated to the reciprocal value of the absolute temperature. Both effects, taken together, lead to a non-linear dependency of the signal intensity on temperature. Therefore a TR leading to maximum temperature dependency of the signal intensity is calculated and used in the futher experiments. In the in vivo experiments, the lower legs of two volunteers are cooled from outside. Images are acquired with a spin-echo sequence (1.5T, TR=1200 ms, TE=10 ms). A rise in signal intensity in the muscle with falling skin temperature is observed, particularly in more peripheral muscle layers. This study shows that spin-echo sequences can be used to monitor temperature changes and temperature differences in living muscle tissue.     

Differential inhibition of cyclooxygenase-1 (COX-1) and-2 (COX-2) by NSAIDS: Consequences on anti-inflammatory activity versus gastric and renal safety

The discovery of an inducible isoform of cyclooxygenase (COX-2) requires a refinement of the theory that inhibition of cyclooxygenase activity is responsible for both therapeutic and side-effects of nonsteroidal anti-inflammatory drugs (NSAIDs). Pharmacological results with developmental compounds suggest that COX-2 is the relevant target for the therapeutic (i.e. anti-inflammatory) effects of NSAIDs, whereas gastric and renal side-effects are related to inhibition of constitutive COX-1. However a role of COX-1 in inflammation cannot be excluded. Furthermore, more research effort is needed to investigate the functional relevance of COX-2 in normal tissue.     

Chemical shift differences between free and Fab-bound peptide correlate with a two-stage selection of peptide sequences from a random phage display library to delineate critical and non-critical residues for antibody recognition

Epitope libraries provide a method to identify peptide ligands for antibodies, receptors or other binding proteins. As such, they provide a powerful tool to rapidly identify lead ligands in the drug discovery process. In an attempt to correlate structural information with the results from peptide screening, we have used NMR spectroscopy of peptide/antibody complexes to demonstrate that core residues identified through a two-stage selection process undergo a larger structural change upon binding antibody than do positions in the peptide amenable to a variety of side chains. The model system used was the M2 monoclonal antibody/Flag? octapeptide epitope system. We have analyzed two peptides: Ac-Asp-Tyr-Lys-Leu-Gly-Asp-Asp-Leu-NH₂ (peptide l), which contains several non-core positions randomized, and Ac-Asp-Tyr-Lys-Asp-Asp-Asp-Asp-Leu-NH₂ (peptide 2), which closely corresponds to the original Flag? sequence. Enrichment of the peptides with ¹⁵N facilitated the investigation by permitting spectral editing of the peptide resonances in the presence of antibody. For peptide 1 the absolute shifts for the free vs. Fab-bound peptide were found to be largest for the amide groups of Asp-1 and Asp-6, in agreement with classification of these residues as critical by the phage display library selection process. For peptide 2 the largest absolute shifts were observed for Asp-1 and Asp-4, with the other aspartic acid residues also showing significant but smaller changes. © Munksgaard 1995.