Metal-catalyzed oxidation of human serum albumin: conformational and functional changes. Implications in protein aging

Abstract Mild oxidative stress, as elicited by ascorbate, oxygen, and trace metals, affects the binding properties of human serum albumin via purely conformational changes. In fact, no gross alteration can be observed in the electrophoretic and chromatographic patterns of albumin, whereas localized modifications are indicated by the changes in absorption and fluorescence spectra and in polarization degree. The oxidized protein presents a small increase of bityrosine production and a time-dependent increase in the content of carbonyl groups, whereas proteolytic susceptibility is unchanged. A higher affinity for cis-parinaric acid and a slight loss of solubility in high salt indicate a greater surface hydrophobicity. Pinpoint denaturation of the albumin molecule is also suggested by a decreased "esterase" activity in the presence of p-nitrophenyl acetate. Conformational stability evaluated through thermal shock and addition of moderate amounts of guanidine indicate that the oxidized protein is more heat-resistant, less flexible, and more rigid than the native one. Although limited, structural damages afforded by the oxidative stress cause alterations of albumin binding properties as documented by experiments with probes and physiological ligands. The loss of biological activity of human serum albumin induced by ascorbate system appears of medical relevance, because it can affect drug metabolism and particularly drug tolerance in the elderly

Prevalenza della sclerosi multipla nell'isola d'Elba

Introduzione Le variazioni temporali e geografiche della frequenza di Sclerosi Multipla (SM) sono state molto studiate. Negli ultimi 30 anni, gli studi epidemiologici hanno evidenziato come la distribuzione della malattia nei paesi dell’area mediterranea, anche in Italia, sia più complessa di quanto ritenuto in passato quando era comunemente accettato il modello correlato alla latitudine (1, 2). Scarsi sono i dati di prevalenza relativi all’Italia centrale e in particolare ad oggi non sono noti dati pubblicati sulla dimensione di questa patologia nella popolazione dell’isola d’Elba. Obiettivi Calcolare la prevalenza della SM nell’isola d’Elba dal momento che non ci sono dati disponibili in letteratura. Metodi L'isola d'Elba è l’isola più grande dell'Arcipelago Toscano e la terza più grande d'Italia dopo la Sicilia e la Sardegna (223 km²). Al giorno di prevalenza, ovvero il 31/12/2010, la popolazione residente nell’isola era pari a 31.943 abitanti. I casi di SM sono stati identificati consultando le cartelle cliniche dell’ospedale e dell’ambulatorio di riferimento neurologico dell’isola. Sono stati arruolati nello studio tutti i pazienti con diagnosi di SM secondo i criteri di McDonald, residenti nell’isola al giorno di prevalenza. Sono stati calcolati i tassi di prevalenza grezzi e specifici (sesso e età) e il tasso standardizzato rispetto alla popolazione italiana del 2001. Gli intervalli di confidenza al 95% dei tassi di prevalenza sono stati calcolati assumendo una distribuzione di Poisson. Risultati Al giorno di prevalenza erano residenti nell’isola 42 soggetti con SM. Di questi il 59,5% era nato ed era tutt’ora residente nell’isola, mentre il 40,5% era nato fuori dall’isola. Tra i 42 soggetti con SM, 4 avevano origine sarda. Il rapporto F:M è risultato pari a 2,8: infatti il 73,8% era di sesso femminile rispetto al 26,2% di sesso maschile. L’età media dei soggetti era di 49,8±12,6 anni e non si osservano differenze significative tra i sessi riguardo all’età (M: 52,9±10,7, F: 48,7±12,6; p = 0,329). Per quanto riguarda le forme di malattia, il 16,7% dei pazienti aveva una forma CIS, il 61,9% una RR, il 16,7% una SP e il 4,8% una PP. Il grado di disabilità (EDSS) è risultato correlato (trend crescente) con la forma di malattia: EDSS pari a 1,5 per le forme CIS, 2,0 per le forme RR e 6,0 per le forme SP e PP. La durata di malattia, in media, era di 15,0±9,8 anni, con un range tra 0 e 37 anni. La durata media di malattia è risultata più alta per i maschi (19,3±9,5 anni) rispetto alle femmine (13,6±9,6 anni) ma tale differenza non è statisticamente rilevante (p = 0,109). Il tasso di prevalenza grezzo è risultato pari a 131,5 (IC 95%: 99,8-177,7) per 100.000 (maschi 70,7; femmine 189,2 per 100.000). Il tasso di prevalenza standardizzato è risultato pari a 131,5 (IC 95%: 91,8-171,2) per 100.000. Il tasso di prevalenza sesso età specifico mostra un picco, per entrambi i sessi, nella classe di età tra 45-54 anni, mentre non ci sono casi prima dei 15 anni

Viability of Legionella pneumophila in Water Samples: A Comparison of Propidium Monoazide (PMA) Treatment on Membrane Filters and in Liquid

Legionella pneumophila is a ubiquitous microorganism widely distributed in aquatic environments and can cause Legionellosis in humans. A promising approach to detect viable cells in water samples involves the use of quantitative polymerase chain reaction (qPCR) in combination with photoactivatable DNA intercalator propidium monoazide (PMA). However, the PMA efficiency could be different depending on the experimental conditions used. The aim of this study was to compare two PMA exposure protocols: (A) directly on the membrane filter or (B) in liquid after filter washing. The overall PMA-induced qPCR means reductions in heat-killed L. pneumophila cells were 2.42 and 1.91 log units for exposure protocols A and B, respectively. A comparison between the results obtained reveals that filter exposure allows a higher PMA-qPCR signal reduction to be reached, mainly at low concentrations (p < 0.05). This confirms the potential use of this method to quantify L. pneumophila in water with low contamination

Peracetic Acid (PAA) Disinfection: Inactivation of Microbial Indicators and Pathogenic Bacteria in a Municipal Wastewater Plant.

Several studies have noted that treated and untreated wastewaters are primary contributors of a variety of pathogenic microorganisms to the aquatic ecosystem. Conventional wastewater treatment may not be sufficient to achieve microbiologically safe effluent to be discharged into natural waters or reused, thus requiring wastewater effluents to be disinfected. In recent years, peracetic acid (PAA) has been adopted as a disinfectant for wastewater effluents. The aim of this study was to evaluate the disinfection efficiency of PAA at low doses (range 0.99–2.10 mg/L) against microbial indicators and pathogenic bacteria in a municipal wastewater plant. Samples of untreated sewage and effluents before and after PAA treatment were collected seasonally for 1 year and were analysed for pathogenic Campylobacter, Salmonella spp., E. coli O157:H7 and E. coli virulence genes using molecular methods; moreover, the detection of specific microbial indicators (E. coli, faecal coliforms, enterococci, C. perfringens) and Salmonella spp. were carried out using culturing methods. Salmonella spp. DNA was found in all untreated sewage and effluent before PAA treatment, whereas it was recovered in 50% of the samples collected after PAA treatment. Although E. coli O157:H7 was never identified, the occurrence of Shiga-like toxin I amplicons was identified in 75% of the untreated sewage samples, in 50% of the effluents assayed before PAA treatment, and in 25% of the effluents assayed after PAA treatment, whereas the stx2 gene was never found. Campylobacter coli was only detected in one effluent sample before PAA treatment. In the effluents after PAA treatment, a lower load of indicator bacteria was observed compared to the effluents before treatment. The results of this study highlight that the use of low doses of PAA seems to lead to an improvement of the microbiological quality of the effluent, although it is not sufficient to guarantee its suitability for irrigation. These results underscore the need for additional studies to further assess the efficiency of PAA disinfection in municipal wastewater plants

Biochemical Alterations in Semen of Varicocele Patients: A Review of the Literature

Oxidative stress is a mechanism underlying different kinds of infertility in human males. However, different results can be observed in relation to the method used for its evaluation. Varicocele patients show a number of biochemical abnormalities, including an altered distribution of coenzyme Q between seminal plasma and sperm cells and also an apparent defect in the utilization of antioxidants. Moreover, an influence of systemic hormones on seminal antioxidant system was observed too. Finally, the effects of surgical treatment on oxidativestress indexes and the possible usefulness of some medical therapies, like coenzyme Q supplementation, are discussed. In conclusion, published data show a role of oxidative stress in varicocele-related male infertility, but at present we do not know the precise molecular mechanisms underlying these phenomena

Relationships Between Thyroid Hormones, Insulin-Like Growth Factor-1 and Antioxidant Levels in Hypothalamic Amenorrhea and Impact on Bone Metabolism

AbstractReduced bone mineral density (BMD) in Functional Hypothalamic Amenorrhea (FHA) is mainly related to hypoestrogenism, but other hormonal derangement (reduced conversion of T4–T3 and GH resistance) can play a role. These hormones are involved in antioxidant systems regulation. We evaluated the impact of hormonal alterations, with special focus on low T3 and IGF-1 levels, on antioxidant systems as a link with osteoporosis in FHA. Forty-three FHA patients, 15–34 years, with BMI range 17.3–23.4 kg/m2, were divided in 2 groups according to fT3 levels; group A (n=22), low fT3 (<2.4 pg/ml) and group B (n=21), normal fT3 (≥ 2.4 pg/ml). We evaluated hormonal parameters (fT3, fT4, TSH, IGF-1, FSH, LH, estradiol, DHEAS, testosterone, cortisol), bone metabolism (calcium, phosphorus, 25-OH Vitamin D, PTH, β-crosslaps, bone alkaline phosphatase) and total antioxidant capacity (TAC), expressed as LAG (latency time in radical species appearance using spectrophotometric method). BMD was assessed by DEXA. Group A patients exhibited significantly lower levels of IGF-1 (159.76±14.79 vs. 220.05±15.25 ng/ml) and osteocalcin (17.51±1.14 vs. 21.49±1.56 ng/ml); LAG values were significantly higher in A (66.33±1.74 s) vs. B (54.62±1.74 s). A significant direct correlation was found between both IGF-1 and fT3 with osteocalcin (r²=0.22, p=0.0049 and r²=0.34, p=0.0001, respectively). No difference in LAG between groups according to IGF-1 were found. These data show a correlation between altered bone turnover and low fT3, which is highly prevalent in FHA. Low fT3 levels may contribute to reduced BMD. Oxidative stress could be the link underlying different bone turnover pattern and endocrine dysfunction in FHA