Study of laser fluorescence spectroscopy in livers of rats with hypothermic ischemia

Purpose: After partial hepatectomy (PH), the remaining liver (RL) undergoes regenerative response proportional to the host. Limited literature exists on hepatic viability after tissue injury during hypothermic preservation. Spectroscopy measures cellular fluorescence and is explored for tissue characterization and parameter investigation. This study aimed to assess fluorescence analysis (spectroscopy) in evaluating liver viability and its relationship with hepatic tissue regeneration 24 hours after PH. Additionally, we analyzed liver regeneration in RL after 70% partial hepatectomy under hypothermic conditions with laser irradiation. Methods: Fifty-six Wistar rats were divided into four groups: total non-perfused liver (control), total perfused liver, partial hepatectomy "in situ", and partial hepatectomy "ex situ". Tissue analysis was performed at 0 and 24 hours using spectroscopy with laser devices emitting at 532 (green) and 405 nm (violet). Results: Spectroscopy identified tissue viability based on consistent results with Ki67 staining. The fluorescence spectra and Ki67 analysis displayed similar patterns, linking proliferative activity and absorption intensity. Conclusions: Fluorescence spectroscopy proves to be promising for real-time analysis of cellular activity and viability. Metabolic activity was observed in groups of live animals and hypothermically preserved samples, indicating cellular function even under blood deprivation and hypothermic conditions.

Do Archaea and bacteria co-infection have a role in the pathogenesis of chronic chagasic cardiopathy?

Chronic cardiopathy (CC) in Chagas disease is a fibrotic myocarditis with C5b-9 complement deposition. Mycoplasma and Chlamydia may interfere with the complement response. Proteolytic enzymes and archaeal genes that have been described in Trypanosoma cruzi may increase its virulence. Here we tested the hypothesis that different ratios of Mycoplasma, Chlamydia and archaeal organisms, which are frequent symbionts, may be associated with chagasic clinical forms. MATERIALS AND METHODS: eight indeterminate form (IF) and 20 CC chagasic endomyocardial biopsies were submitted to in situ hybridization, electron and immunoelectron microscopy and PCR techniques for detection of Mycoplasma pneumoniae (MP), Chlamydia pneumoniae(CP), C5b-9 and archaeal-like bodies. RESULTS: MP and CP-DNA were always present at lower levels in CC than in IF (p < 0.001) and were correlated with each other only in CC. Electron microscopy revealed Mycoplasma, Chlamydia and two types of archaeal-like bodies. One had electron dense lipid content (EDL) and was mainly present in IF. The other had electron lucent content (ELC) and was mainly present in CC. In this group, ELC correlated negatively with the other microbes and EDL and positively with C5b-9. The CC group was positive for Archaea and T. cruzi DNA. In conclusion, different amounts of Mycoplasma, Chlamydia and archaeal organisms may be implicated in complement activation and may have a role in Chagas disease outcome.