Glutathionylation of the iron superoxide dismutase from the psychrophilic eubacterium Pseudoalteromonas haloplanktis.

Our previous work showed that the adduct between beta-mercaptoethanol and the single cysteine residue (Cys57) in superoxide dismutase from the psychrophilic eubacterium Pseudoalteromonas haloplanktis (PhSOD) reduces the enzyme inactivation by peroxynitrite. In this work, immunoblotting experiments prove that peroxynitrite inactivation of PhSOD involves formation of nitrotyrosine residue(s). In order to study the role of Cys57 as a redox-sensor residue modifiable by cellular thiols, a recombinant PhSOD and two Cys57 mutants were produced and characterized. Recombinant and mutant enzymes share similar activity and peroxynitrite inactivation, but different reactivity towards three glutathione forms. Indeed, oxidized glutathione and S-nitrosoglutathione, but reduced glutathione, lead to S-glutathionylation of recombinant PhSOD. This new covalent modification for a Fe-SOD does not occur in both Cys57 mutants, thus indicating that its target is Cys57. Moreover, mass spectrometry analysis confirmed that S-glutathionylation of Cys57 takes place also with endogenous PhSOD. Formation of this mixed disulfide in PhSOD protects the enzyme from tyrosine nitration and peroxynitrite inactivation. PhSOD undergoes S-glutathionylation during its overproduction in E. coli cells and in a growing culture of P. haloplanktis. In both cases the extent of glutathionylated PhSOD is enhanced upon cell exposure to oxidative agents. We suggest that S-glutathionylation of PhSOD could represent a further cold-adaptation strategy to improve the antioxidant cellular defence mechanism.

25-Hydroxy Vitamin D Detection Using Different Analytic Methods in Patients with Migraine.

OBJECTIVES: The aim of this study was to evaluate the performance of different analytic methods, such as liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), high-performance liquid chromatography-ultraviolet (HPLC-UV), enzyme-linked immunosorbent assay (EIA), and chemiluminescence immunoassays (CLIA), in order to highlight whether or not there is relative superiority amongst the assays. We analyzed two groups of subjects suffering from headache and two groups of healthy subjects. DESIGN AND METHODS: We performed a prospective, single-blind single-center control-group study on 220 subjects with migraine. Subjects of both sexes >10 years old and with 12 months' history of migraine were eligible for the study. As a control group, 120 healthy subjects were chosen by their family physician. RESULTS: LC-MS/MS evaluation documented that in all enrolled subjects (migraine and control groups), the serum vitamin D3 levels were lower with respect to the normal range (30-100 ng/mL), with a mean value of 15.4 ng/mL, without difference between sex. The mean values measured using HPLC-UV, EIA, and CLIA tests such as Liaison® and Architect® did not show significant differences compared to the values obtained using LC-MS/MS. CONCLUSIONS: In conclusion, the population generally has low values of the vitamin D3 hormone, and the suggested range should probably be revised. HPLC-UV and CLIA were found to have appropriate analytical values compared to the reference method (LC-MS/MS), so it is possible to suggest their routine use to optimize care.

Conventional and New Antiepileptic Drugs on Vitamin D and Bone Health: What We Know to Date?

The treatment with antiepileptic drugs (AEDs), in particular conventional drugs, induces an increased risk of fractures in women and in epileptic patients in treatment with AEDs for more than 12 years. A supplementation with calcium and vitamin D is suggested in patients chronically treated with some AEDs and there are recommendations to do so. The lack of significant conclusive evidence about the effects of conventional and newer AEDs on bone metabolism needs for more clinical studies in order to perform an appropriate use of calcium and vitamin D supplementation in young and ederly epileptic patients.

Different Omega-3 Formulations Yield to Diverse Clinical Response: A Case-Report.

Treatment guidelines recommend omega-3 with Docosahexaenoic Acid (DHA) and Eicosapentaenoic Acid (EPA) content not above 85% in patients with high plasma levels of triglycerides. Since the different up to date formulation of omega-3 available in commerce must be similar to clinical efficacy and safety, herein, we report the case a 52-year-old woman who presented clinical inefficacy using Olevia(®) omega-3 treatment. Clinical evaluation excluded the presence of intestinal or systemic diseases able to reduce the drug absorption. Switching the therapy from (Olevia(®)) to an equivalent omega-3 formulation (Esapent(®)), we documented a decrease in her plasma triglycerides levels. In order to evaluate a possible difference between these formulations we performed a single blind in vitro dissolution test using three pills for each formulation of omega-3 (Olevia(®), Esapent® and another one chosen between the several formulations available in commerce: DOC Generic(®)) that revealed a significant difference (>20%) in the dissolution time of three different omega- 3 commercially available drug formulation.

Recognizing Severe Adverse Drug Reactions: Two Case Reports After Switching Therapies to the Same Generic Company.

Generic formulations represent a way to reduce the costs of brand compounds when their patent is expired. While, the bio-equivalence in generic drugs is guaranteed, some excipients as well as dyes could be different and this could reduce the drug safety. Herein, we report the development of Adverse Drug Reactions (ADRs) in two patients after the switch from brand to generic formulations. We have tested cytochrome P450 enzymes expression as well as drug serum levels. None of these markers were altered. Checking deeply into both patient's medical history, they harbored poly-sensitivity or allergy to pollen and graminacea and used different active ingredients for different health problems coming from the same generic company Almus(®). This company used different dyes and excipients compared to the branded drugs made by distinguished companies. In conclusion, we strongly suggest to both pharmacists and physicians to be careful in giving the advice to change the drug, thinking to reduce health sanitary costs without considering the personal clinical history of each one. Paradoxically this behavior is causing other health issues, bringing to an increase of the overall costs for patients as well as for National Health System.

EDTA is essential to recover lead from dried blood spots on filter paper.

BACKGROUND: Residual dried blood spots (DBSs) on filter paper from neonatal screening have been proposed as samples for population survey of lead contamination. We have investigated the EDTA effect on lead release in the eluting solution. METHODS: Furnace atomic absorption spectrophotometry has been used for lead measurements. Standard, blank and sample solutions contained 2% m/v NH(4)H(2)PO(4), 0.5% v/v Triton X-100 and 0.2% v/v HNO(3) as matrix modifier solution (MMS) with or without EDTA. A calibration curve was established from aqueous standard solutions. Paper discs from DBS and blank, punched near the DBS, were eluted in MM solution and, where required, EDTA at different concentrations. Specimens were leftover DBSs with different storage times, matched samples from 20 adult patients consisting of liquid whole blood (LWB) containing 5 mmol/L EDTA, DBSs eluted in MM solution with 5 mmol/L EDTA or without EDTA. RESULTS: Optimal lead recovery from DBS required 5 mM EDTA in the eluting solution. Mean lead levels of LWB and DBSs eluted with EDTA were similar and higher than DBSs without EDTA (P<0.001). Without EDTA, the median value of lead optical density was lower for 6-month-old DBSs than for blanks (P<0.001). CONCLUSIONS: Residual DBSs can be used for population survey, but 5 mmol/L EDTA in the extracting solution is required to fully recover lead.

Properties of a putative cambialistic superoxide dismutase from the aerotolerant bacterium Streptococcus thermophilus strain LMG 18311.

The aerotolerance of the lactic - fermentative bacterium Streptococcus thermophilus is mainly based on the key antioxidant function of superoxide dismutase (StSOD). In this work, the comparison of recombinant StSOD (rStSOD) forms obtained from two different initiation triplets indicated that the enzyme from S. thermophilus strain LMG 18311 spans 201 residues. rStSOD is organised as a homodimer, even though protein aggregates are formed in concentrated solutions. The capability of binding and exchanging Fe or Mn in the active site classifies rStSOD as a putative cambialistic enzyme; the moderate preference for iron is counteracted by a 1.5-fold higher activity measured for the Mn-containing form. The enzyme is thermostable, being its half-inactivation time 10 min at 73.5°C; the energetic parameters of the heat inactivation process are regulated by the level of Mn cofactor. The effect of Mn content on the rStSOD sensitivity towards inhibitors and inactivators was also evaluated. Sodium azide acts as a weak inhibitor of rStSOD and its Mn content does not greatly affect this sensitivity. Concerning the physiological inactivator hydrogen peroxide, the Mn-enriched rStSOD displays a great resistance; a moderate sensitivity is instead observed in the presence of a low Mn content. Contrary to hydrogen peroxide, sodium peroxynitrite is a powerful inactivator, a behaviour enhanced in the Mn-enriched enzyme. All these results were compared with the corresponding data previously reported for the cambialistic SOD from the taxonomically related S. mutans. In S. thermophilus the regulation of the enzyme functions by the Mn content appears less relevant with respect to S. mutans.

Clinical evolution of autoimmune thyroiditis in children and adolescents.

BACKGROUND: Few studies have addressed the clinical evolution of autoimmune thyroiditis (AIT) occurring in childhood and scant data are available on the role of thyroid ultrasonography. We aimed to evaluate the natural history of AIT diagnosed in children and adolescents and to assess the possible prognostic role of ultrasonography. METHODS: Retrospective case series prospectively followed up for a further 3-year period. RESULTS: A series of 23 patients with AIT, diagnosed before 18 years of age from 1994 to 2004, was further followed up from 2005 to 2007 with clinical, laboratory, and ultrasound evaluation. Hypothyroid patients were treated with levothyroxine (LT(4)), while euthyroid patients were left untreated. Patients with subclinical hypothyroidism were also evaluated 40 days after LT(4) withdrawal. At diagnosis seven patients were euthyroid, 14 with subclinical hypothyroidism, and two with overt hypothyroidism. Median follow-up was 4.7 years. At last follow-up visit, none of the seven euthyroid patients had developed hypothyroidism. Three of the 14 patients with subclinical hypothyroidism recovered a normal thyroid function while only one patient showed an increase in TSH level. By serological screening we identified three patients with other autoimmune disorders. CONCLUSIONS: In young patients with normal or mildly increased TSH levels and minimal echographic changes, AIT may remain stationary for years. In fact, patients with subclinical hypothyroidism recover a normal thyroid function in approximately 20% of cases. In patients with subclinical hypothyroidism and goiter, LT(4) therapy may induce thyroid size reduction. Screening for other autoimmune disorders is useful to identify patients that need further diagnostic assessment.

Rat mitochondrial manganese superoxide dismutase: amino acid positions involved in covalent modifications, activity, and heat stability.

The role of three amino acid residues (Q143, Y34, S82) of rat mitochondrial superoxide dismutase (ratSOD2) in the enzymatic activity, thermostability, and post-translational modification of the enzyme was investigated through site-directed mutagenesis studies. Six recombinant forms of the enzyme were produced, carrying the Q143 or H143 residue with or without the Y34F or S82A replacement. All proteins bound manganese as active cofactor and were organized as homotetramers. The greatest effect on the activity (sixfold reduction) was observed in ratSOD2 forms containing the H143 variant, whereas Y34F and S82A substitutions moderately reduced the enzymatic activity compared to the Q143 form. Heat inactivation studies showed the high thermo-tolerance of ratSOD2 and allowed an evaluation of the related activation parameters of the heat inactivation process. Compared to Q143, the H143 variant was significantly less heat stable and displayed moderately lower enthalpic and entropic factors; the Y34F substitution caused a moderate reduction of heat stability, whereas the S82A replacement slightly improved the thermo-tolerance of the Q143 variant; both substitutions significantly increased enthalpic and entropic factors of heat inactivation, the greatest effect being observed with S82A substitution. All recombinant forms of ratSOD2 were glutathionylated in Escherichia coli, a feature pointing to the high reactivity of ratSOD2 toward glutathione. Moreover, the S82 position of the enzyme was phosphorylated in an in vitro system containing human mitochondrial protein extracts as source of protein kinases. These data highlight the role played by some residues in ratSOD2 and suggest a fine regulation of the enzyme occurring in vivo.