Association of body iron stores with low molecular weight iron and oxidant damage of human atherosclerotic plaques

The association between iron, an oxidant catalyst, and atherosclerosis is controversial. In particular, it is unknown whether: (1) stored iron, namely serum ferritin, is correlated with catalytic iron and oxidant damage of human atherosclerotic plaques; (2) catalytic iron is related to oxidative injury within such plaques; (3) plaque oxidant burden is associated with the severity of atherosclerosis. Thus, we assessed low molecular weight iron (LMWI), which represents the metal catalytically active form, together with fluorescent damage products of lipid peroxidation (FDPL) and lipid hydroperoxides (LOOH), in 38 atherosclerotic plaques surgically removed from 38 patients who had undergone selective carotid endarterectomy. In each patient, the levels of serum ferritin were measured and correlated with those of plaque LMWI and lipoperoxides by the Spearman rank correlation test with Spearman rank correlation coefficient (r(S)) calculation. Moreover, in patients selected from the same study population, we compared plaque analyte levels between two groups with different severity of atherosclerotic carotid stenosis, i.e., <90% (group A, n = 25) or > or =90% (group B, n = 13), and between another two groups without (group C, n = 27) and with (group D, n = 11) associated contralateral carotid stenosis > or =50%, indicative of "extensive" and more severe atherosclerotic disease. In group A patients, serum ferritin was directly and significantly correlated with plaque LMWI (r(S) = 0.46, P < 0.025) and FDPL (r(S) = 0.58, P < 0.005), while its correlation with plaque LOOH, albeit direct, did not attain statistical significance. Moreover, a direct and significant relationship was evident between the plaque content of LMWI and that of both FDPL (r(S) = 0.61, P < 0.0025) and LOOH (r(S) = 0.51, P < 0.025), suggesting a prooxidant role of catalytic iron within human atherosclerotic plaques. Considering the 13 patients of group B, a positive and significant correlation was observed between the levels of serum ferritin and those of plaque LMWI (r(S) = 0.83, P < 0.0001); on the other hand, serum ferritin, as well as plaque LMWI, showed no significant correlation with either plaque FDPL or LOOH, conceivably reflecting the small number of patients belonging to group B. Finally, plaque LMWI, FDPL, and LOOH content was significantly higher in group B than in group A, and in group D than in group C. These data suggest a role for catalytic iron in atherosclerotic plaque oxidation and in the severity of atherosclerosis, which appears indeed associated with plaque oxidant burden.     

Preoperative bi-fractionated accelerated radiation therapy for combined treatment of locally advanced rectal cancer in a consectutive series of unselected patients

Background

although preoperative RT (Radiation Therapy) is becoming the preferred approach for combined treatment of locally advanced rectal adenocarcinoma, no regimen can be now considered as a standard. Since the toxicity of preoperative RT isn't yet completely known, and the advantages of preoperative RT could be counterbalanced by increased postoperative morbidity and mortality, a monocentre series of preoperative bifractionated accelerated RT was retrospectively reviewed to clarify toxicity and outcomes after a prolonged follow up.

Methods

patients were screened following these eligibility criteria: histology-proven adenocarcinoma of the rectum; distal tumour extent at 12 cm or less from the anal verge; clinical stage T3–4/anyN, or anyT/N1–2; ECOG Performance Status 0–2. A total dose of 41.6 Gy (26 twice daily fractions of 1.6 Gy) was delivered. Surgery was carried out 17 ± 2 days after RT completion, adopting the total mesorectal excision technique.

Results

24 men and 23 women were enrolled; median age was 55 years (r.: 39–77). Twenty-eight patients were stage II and 19 stage III. 9 patients suffered from a recurrent tumour. 2 patients experienced a severe grade 4 gastrointestinal toxicity (a colo-vaginal fistula and an intestinal obstruction, both successfully treated). Operative mortality was nil; postoperative early complications occurred in 13 cases; mean length of hospital stay was 15 days. After a mean follow up of 44 months (r.: 18–84) 8 patients had deceased for recurrent disease, 15 were alive with a disease progression (2 pelvic recurrences and 13 pure distant deposits) and 24 were alive, without disease. The 5-year actuarial overall survival was 74.2%, the disease-free survival 62.9% and the regional control rate 84.7%. Long-term complications included 1 case of radiation enteritis requiring surgery, 2 cases of anastomotic stricture and 3 cases of bladder incontinence.

Conclusion

bifractionated accelerated RT administered in the preoperative setting to patients bearing locally advanced rectal cancer is reliable and safe, as its immediate and late toxicity (mainly infectious) is acceptably low and long-term survivals are achievable. These findings support the increasing use of preoperative RT for treatment of this malignancy in experienced centres. Ongoing multicentric trials are expected to address still unsolved issues, including the benefit of CT adjunct to preoperative RT.

     

Phenols removal in musts: Strategy for wine stabilization by laccase

The potential of laccase from Trametes versicolor for phenolic removal in must for wine stabilization was evaluated through a combination of an analytical methodology (capillary zone electrophoresis) and kinetics of phenols removal as the total antioxidant potential variation. Total phenolic content, total antioxidant potential and polyphenols were monitored from 0 to 3 h of must treatment. The results indicated that the treatment of a red must with laccase affect mainly the phenolic compounds responsible for the must antioxidant properties. The treatment of white musts with laccase showed higher reduction in total phenol than in the total antioxidant potential. Phenol degradation by laccase was very fast for catechins, and slowly for stilbenes (cis- and trans-resveratrol) and derivatives of cinnamic (ferulic and caffeic) and benzoic (syringic, vanillic, and gallic) acids. It is possible to conclude in this case that the use of laccase in white wines is perfectly feasible. This would allow softer and ecologically correct treatments, which would diminish the cost of processing and avoid deterioration of wines for long storage times.     

A case of furuncular myiasis associated with systemic inflammation

Cutaneous myiasis is a common travel-associated dermatosis caused by fly larvae. We report an unusual case of furuncular myiasis caused by Dermatobia hominis that was associated with signs of systemic inflammation. In this case study, morphological and novel molecular approaches were used to identify and characterize the larvae responsible for human infestation.     

1-(7-Chloroquinolin-4-yl)-N-(4-Methoxybenzyl)-5-Methyl-1H-1,2, 3-Triazole-4- carboxamide Reduces Aβ Formation and Tau Phosphorylation in Cellular Models of Alzheimer’s Disease

1-(7-Chloroquinolin-4-yl)-N-(4-methoxybenzyl)-5-methyl-1H-1,2,3-triazole-4- carboxamide (QTC-4-MeOBnE) is a new multi-target directed ligand (MTDL) rationally designed to have affinity with β-secretase (BACE), Glycogen Synthase Kinase 3β (GSK3β) and acetylcholinesterase, which are considered promising targets on the development of disease-modifying therapies against Alzheimer’s Disease (AD). Previously, QTC-4-MeOBnE treatment showed beneficial effects in preclinical AD-like models by influencing in vivo neurogenesis, oxidative and inflammatory pathways. However, the biological effect and mechanism of action exerted by QTC-4-MeOBnE in AD cellular models have not been elucidated yet. Hereby we investigate the acute effect of QTC-4-MeOBnE on neuronal cells overexpressing Amyloid Protein Precursor (APP) or human tau protein, the two main features of the AD pathophysiology. When compared to the control group, QTC-4-MeOBnE treatment prevented amyloid beta (Aβ) formation through the downregulation of APP and BACE levels in APPswe-expressing cells. Furthermore, in N2a cells overexpressing human tau, QTC-4-MeOBnE reduced the levels of phosphorylated forms of tau via the modulation of the GSK3β pathway. Taken together, our findings provide new insights into the mechanism of action exerted by QTC-4-MeOBnE in AD cellular models, and further support its potential as an interesting therapeutic strategy against AD.

     

Selective observation of the disordered import signal of a globular protein by in-cell NMR: The example of frataxins

We have exploited the capability of in-cell NMR to selectively observe flexible regions within folded proteins to carry out a comparative study of two members of the highly conserved frataxin family which are found both in prokaryotes and in eukaryotes. They all contain a globular domain which shares more than 50% identity, which in eukaryotes is preceded by an N-terminal tail containing the mitochondrial import signal. We demonstrate that the NMR spectrum of the bacterial ortholog CyaY cannot be observed in the homologous E. coli system, although it becomes fully observable as soon as the cells are lysed. This behavior has been observed for several other compact globular proteins as seems to be the rule rather than the exception. The NMR spectrum of the yeast ortholog Yfh1 contains instead visible signals from the protein. We demonstrate that they correspond to the flexible N-terminal tail indicating that this is flexible and unfolded. This flexibility of the N-terminus agrees with previous studies of human frataxin, despite the extensive sequence diversity of this region in the two proteins. Interestingly, the residues that we observe in in-cell experiments are not visible in the crystal structure of a Yfh1 mutant designed to destabilize the first helix. More importantly, our results show that, in cell, the protein is predominantly present not as an aggregate but as a monomeric species.     

Biliverdin reductase-A protein levels and activity in the brains of subjects with Alzheimer disease and mild cognitive impairment

Biliverdin reductase-A is a pleiotropic enzyme involved not only in the reduction of biliverdin-IX-alpha into bilirubin-IX-alpha, but also in the regulation of glucose metabolism and cell growth secondary to its serine/threonine/tyrosine kinase activity. Together with heme oxygenase, whose metabolic role is to degrade heme into biliverdin-IX-alpha, it forms a powerful system involved in the cell stress response during neurodegenerative disorders. In this paper, an up-regulation of the biliverdin reductase-A protein levels was found in the hippocampus of the subjects with Alzheimer disease and arguably its earliest form, mild cognitive impairment. Moreover a significant reduction in the phosphorylation of serine, threonine and tyrosine residues of biliverdin reductase-A was found, and this was paralleled by a marked reduction in its reductase activity. Interestingly, the levels of both total and phosphorylated biliverdin reductase-A were unchanged as well as its enzymatic activity in the cerebella. These results demonstrated a dichotomy between biliverdin reductase-A protein levels and activity in the hippocampus of subjects affected by Alzheimer disease and mild cognitive impairment, and this effect likely is attributable to a reduction in the phosphorylation of serine, threonine and tyrosine residues of biliverdin reductase-A. Consequently, not just the increased levels of biliverdin reductase-A, but also its changed activity and phosphorylation state, should be taken into account when considering potential biomarkers for Alzheimer disease and mild cognitive impairment.