Rapid monitoring of SARS-CoV-2 variants of concern through high-resolution melt analysis.

The current global pandemic of COVID-19 is characterized by waves of infection due to the emergence of new SARS-CoV-2 variants carrying mutations on the Spike (S) protein gene. Since autumn 2020 many Variants of Concern (VOC) have been reported: Alpha/B.1.1.7, Beta/B.1.351, Gamma/P.1, Delta/B.1.617.2, Omicron/B.1.1.529, and sublineages. Surveillance of genomic variants is currently based on whole-genome sequencing (WGS) of viral genomes on a random fraction of samples positive to molecular tests. WGS involves high costs, extended analysis time, specialized staff, and expensive instruments compared to a PCR-based test. To rapidly identify the VOCs in positive samples, six assays based on real-time PCR and high-resolution melting (HRM) were designed on the S gene and applied to 120 oro/nasopharyngeal swab samples collected from October 2020 to June 2022 (106 positive and 14 negative samples). Overall, the assays showed 100% specificity and sensitivity compared with commercial PCR tests for COVID-19. Moreover, 104 samples out of 106 (98.1%) were correctly identified as follows: 8 Wuhan (wild type), 12 Alpha, 23 Delta, 46 Omicron BA.1/BA.1.1, 15 Omicron BA.2/BA.4/BA.5. With our lab equipment, about 10 samples can be processed every 3 h at the cost of less than € 10 ($ 10.60) per sample, including RNA extraction. The implementation of this approach could help local epidemiological surveillance and clinical decision-making.

Effect of a lifestyle intervention program's on breast cancer survivors' cardiometabolic health: Two-year follow-up.

The purpose of this study is to assess the cardiometabolic responses of a lifestyle intervention (LI) conducted at home among breast cancer (BC) survivors during the two years of COVID-19 pandemic. A 3-month LI focused on diet and exercise was performed on thirty BC survivors (women; stages 0-II; non-metastatic; aged 53.6 ± 7.6 years; non-physically active) with a risk factor related to metabolic/endocrine diseases. Anthropometrics, cardiorespiratory fitness (V˙O2max), physical activity level (PAL), adherence to the Mediterranean diet (MeDiet modified questionnaire), and several biomarkers (i.e., glycemia, insulin, insulin resistance [HOMA-IR] index, triglycerides, high- [HDL] and low- [LDL] density lipoproteins, total cholesterol, progesterone, testosterone, and hs-troponin) were evaluated before and 3-, 6-, 12-, and 24-month after the LI. Beneficial effects of the LI were observed on several variables (i.e., body mass index, waist circumference, MeDiet, PAL, V˙ O2max, glycemia, insulin, HOMA-IR index, LDL, total cholesterol, triglycerides, testosterone) after 3-month. The significant effect on Mediterranean diet adherence and V˙ O2max persisted up to the 24-month follow-up. Decreases in HOMA-IR index and triglycerides were observed up to 12-month, however did not persist afterward. This study provides evidence on the positive association between LI and cardiometabolic health in BC survivors.

Circulating ACE2 level and zinc/albumin ratio as potential biomarkers for a precision medicine approach to COVID-19.

Highly mutable influenza is successfully countered based on individual susceptibility and similar precision-like medicine approach should be effective against SARS-COV-2. Among predictive markers to bring precision medicine to COVID-19, circulating ACE2 has potential features being upregulated in both severe COVID-19 and predisposing comorbidities. Spike SARS-CoVs were shown to induce ADAM17-mediated shedding of enzymatic active ACE2, thus accounting for its increased activity that has also been suggested to induce positive feedback loops leading to COVID-19-like manifestations. For this reason, pre-existing ACE2 activity and inhibition of ACE2/ADAM17 zinc-metalloproteases through zinc chelating agents have been proposed to predict COVID-19 outcome before infection and to protect from COVID-19, respectively. Since most diagnostic laboratories are not equipped for enzymatic activity determination, other potential predictive markers of disease progression exploitable by diagnostic laboratories were explored. Concentrations of circulating albumin, zinc, ACE2 protein and its activity were investigated in healthy, diabetic (COVID-19-susceptible) and SARS-CoV-2-negative COVID-19 individuals. ACE2 both protein levels and activity significantly increased in COVID-19 and diabetic patients. Abnormal high levels of ACE2 characterised a subgroup (16-19%) of diabetics, while COVID-19 patients were characterised by significantly higher zinc/albumin ratios, pointing to a relative increase of albumin-unbound zinc species, such as free zinc ones. Data on circulating ACE2 levels are in line with the hypothesis that they can drive susceptibility to COVID-19 and elevated zinc/albumin ratios support the therapeutic use of zinc chelating inhibitors of ACE2/ADAM17 zinc-metalloproteases in a targeted therapy for COVID-19.

Comparing Heterologous and Homologous COVID-19 Vaccination: A Longitudinal Study of Antibody Decay.

The humoral response after vaccination was evaluated in 1248 individuals who received different COVID-19 vaccine schedules. The study compared subjects primed with adenoviral ChAdOx1-S (ChAd) and boosted with BNT162b2 (BNT) mRNA vaccines (ChAd/BNT) to homologous dosing with BNT/BNT or ChAd/ChAd vaccines. Serum samples were collected at two, four and six months after vaccination, and anti-Spike IgG responses were determined. The heterologous vaccination induced a more robust immune response than the two homologous vaccinations. ChAd/BNT induced a stronger immune response than ChAd/ChAd at all time points, whereas the differences between ChAd/BNT and BNT/BNT decreased over time and were not significant at six months. Furthermore, the kinetic parameters associated with IgG decay were estimated by applying a first-order kinetics equation. ChAd/BNT vaccination was associated with the longest time of anti-S IgG negativization and with a slow decay of the titer over time. Finally, analyzing factors influencing the immune response by ANCOVA analysis, it was found that the vaccine schedule had a significant impact on both the IgG titer and kinetic parameters, and having a Body Mass Index (BMI) above the overweight threshold was associated with an impaired immune response. Overall, the heterologous ChAd/BNT vaccination may offer longer-lasting protection against SARS-CoV-2 than homologous vaccination strategies.

Movement and health beyond care, MoviS: study protocol for a randomized clinical trial on nutrition and exercise educational programs for breast cancer survivors.

BACKGROUND: Breast cancer (BC) is the most common invasive cancer in women, and exercise can significantly improve the outcomes of BC survivors. MoviS (Movement and Health Beyond Care) is a randomized controlled trial aimed to evaluate the potential health benefits of exercise and proper nutritional habits. This study aims to assess the efficacy of aerobic exercise training in improving quality of life (QoL) and health-related factors in high-risk BC. METHODS: One hundred seventy-two BC survivor women, aged 30-70 years, non-metastatic, stage 0-III, non-physically active, 6-12 months post-surgery, and post chemo- or radiotherapy, will be recruited in this study. Women will be randomly allocated to the intervention arm (lifestyle recommendations and MoviS Training) or control arm (lifestyle recommendations). The MoviS training consists of 12 weeks of aerobic exercise training (2 days/week of supervised and 1 day/week of unsupervised exercise) with a progressive increase in exercise intensity (40-70% of heart rate reserve) and duration (20-60 min). Both arms will receive counseling on healthy lifestyle habits (nutrition and exercise) based on the World Cancer Research Fund International (WCRF) 2018 guidelines. The primary outcome is the improvement of the QoL. The secondary outcomes are improvement of health-related parameters such as Mediterranean diet adherence, physical activity level, flexibility, muscular fitness, fatigue, cardiorespiratory fitness (estimated maximal oxygen uptake), echocardiographic parameters, heart rate variability (average of the standard deviations of all 5 min normal to normal intervals (ASDNN/5 min) and 24 h very low and low frequency), and metabolic, endocrine, and inflammatory serum biomarkers (glycemia, insulin resistance, progesterone, testosterone, and high-sensitivity C-reactive protein). DISCUSSION: This trial aims to evaluate if supervised exercise may improve QoL and health-related factors of BC survivors with a high risk of recurrence. Findings from this project could provide knowledge improvement in the field of exercise oncology through the participation of a multidisciplinary team that will provide a coordinated program of cancer care to improve healthcare quality, improve prognosis, increase survival times and QoL, and reduce the risk of BC recurrence. TRIAL REGISTRATION: ClinicalTrials.gov  NCT04818359 . Retrospectively registered on March 26, 2021.

SARS-CoV-2 multi-variant rapid detector based on graphene transistor functionalized with an engineered dimeric ACE2 receptor.

Reliable point-of-care (POC) rapid tests are crucial to detect infection and contain the spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The emergence of several variants of concern (VOC) can reduce binding affinity to diagnostic antibodies, limiting the efficacy of the currently adopted tests, while showing unaltered or increased affinity for the host receptor, angiotensin converting enzyme 2 (ACE2). We present a graphene field-effect transistor (gFET) biosensor design, which exploits the Spike-ACE2 interaction, the crucial step for SARS-CoV-2 infection. Extensive computational analyses show that a chimeric ACE2-Fragment crystallizable (ACE2-Fc) construct mimics the native receptor dimeric conformation. ACE2-Fc functionalized gFET allows in vitro detection of the trimeric Spike protein, outperforming functionalization with a diagnostic antibody or with the soluble ACE2 portion, resulting in a sensitivity of 20 pg/mL. Our miniaturized POC biosensor successfully detects B.1.610 (pre-VOC), Alpha, Beta, Gamma, Delta, Omicron (i.e., BA.1, BA.2, BA.4, BA.5, BA.2.75 and BQ.1) variants in isolated viruses and patient's clinical nasopharyngeal swabs. The biosensor reached a Limit Of Detection (LOD) of 65 cps/mL in swab specimens of Omicron BA.5. Our approach paves the way for a new and reusable class of highly sensitive, rapid and variant-robust SARS-CoV-2 detection systems.

Evaluation of Two-Month Antibody Levels after Heterologous ChAdOx1-S/BNT162b2 Vaccination Compared to Homologous ChAdOx1-S or BNT162b2 Vaccination.

We evaluated the post-vaccination humoral response of three real-world cohorts. Vaccinated subjects primed with ChAdOx1-S and boosted with BNT162b2 mRNA vaccine were compared to homologous dosing (BNT162b2/BNT162b2 and ChAdOx1-S/ChAdOx1-S). Serum samples were collected two months after vaccination from a total of 1248 subjects. The results showed that the heterologous vaccine schedule induced a significantly higher humoral response followed by homologous BNT162b2/BNT162b2 and ChAdOx1-S/ChAdOx1-S vaccines (p < 0.0001). Moreover, analyzing factors (i.e., vaccine schedule, sex, age, BMI, smoking, diabetes, cardiovascular diseases, respiratory tract diseases, COVID-19 diagnosis, vaccine side effects) influencing the IgG anti-S response, we found that only the type of vaccine affected the antibody titer (p < 0.0001). Only mild vaccine reactions resolved within few days (40% of subjects) and no severe side effects for either homologous groups or the heterologous group were reported. Our data support the use of heterologous vaccination as an effective and safe alternative to increase humoral immunity against COVID-19.

Which ones, when and why should renin-angiotensin system inhibitors work against COVID-19?

The article describes the possible pathophysiological origin of COVID-19 and the crucial role of renin-angiotensin system (RAS), providing several "converging" evidence in support of this hypothesis. SARS-CoV-2 has been shown to initially upregulate ACE2 systemic activity (early phase), which can subsequently induce compensatory responses leading to upregulation of both arms of the RAS (late phase) and consequently to critical, advanced and untreatable stages of COVID-19 disease. The main and initial actors of the process are ACE2 and ADAM17 zinc-metalloproteases, which, initially triggered by SARS-CoV-2 spike proteins, work together in increasing circulating Ang 1-7 and Ang 1-9 peptides and downstream (Mas and Angiotensin type 2 receptors) pathways with anti-inflammatory, hypotensive and antithrombotic activities. During the late phase of severe COVID-19, compensatory secretion of renin and ACE enzymes are subsequently upregulated, leading to inflammation, hypertension and thrombosis, which further sustain ACE2 and ADAM17 upregulation. Based on this hypothesis, COVID-19-phase-specific inhibition of different RAS enzymes is proposed as a pharmacological strategy against COVID-19 and vaccine-induced adverse effects. The aim is to prevent the establishment of positive feedback-loops, which can sustain hyperactivity of both arms of the RAS independently of viral trigger and, in some cases, may lead to Long-COVID syndrome.

A comprehensive UHPLC-MS/MS screening method for the analysis of 98 New Psychoactive Substances and related compounds in human hair.

In this study, a rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the targeted analysis of 98 New Psychoactive Substances (NPS) from the hair matrix. The monitored compounds included various chemical classes (7 phenethylamines, 10 tryptamines, 18 cathinones, 24 synthetic opioids, and 38 synthetic cannabinoids) with emphasis given to newly emerged NPS. The method employed a direct extraction process through the incubation of hair samples (25 mg) and internal standards with M3® reagent at 100 °C for 60 min, followed by extract purification through acid and basic liquid-liquid micro-extraction (LLME). Extracted compounds were analyzed through LC-MS/MS system operating in multiple reaction monitoring mode. NPS were separated in 9.5 min with a Poroshell 120 EC-C18 column (2.7 µm, 4.6 × 50 mm) using a gradient eluting mobile phase composed of water and acetonitrile/water (95:5) both containing 0.1 % of formic acid. The developed and validated method shows a good precision (≤ 15 %), linearity (R2 between 0.993 and 0.999), selectivity, and sensitivity (LOD: 0.6-10.3 pg mg-1 and LOQ: 2.1-34.4 pg mg-1). The method showed also reduced matrix effect and acceptable recovery for most of the targeted compounds. Our results showed that this method is suitable for quantifying NPS in hair matrix and could be employed in the context of routine analyses in analytical laboratories.

Effects of a Home-Based Lifestyle Intervention Program on Cardiometabolic Health in Breast Cancer Survivors during the COVID-19 Lockdown.

This study aimed to evaluate the cardiometabolic effects of a home-based lifestyle intervention (LI) in breast cancer survivors (BCSs) during the COVID-19 lockdown. In total, 30 BCSs (women; stages 0-II; non-metastatic; aged 53.5 ± 7.6 years; non-physically active; normal left ventricular systolic function) with a risk factor for recurrence underwent a 3-month LI based on nutrition and exercise. Anthropometrics, Mediterranean diet adherence, physical activity level (PAL), cardiorespiratory fitness (VO2max), echocardiographic parameters, heart rate variability (average standard deviation of NN intervals (ASDNN/5 min) and 24 h very- (24 hVLF) and low-frequency (24 hLF)), and metabolic, endocrine, and inflammatory serum biomarkers (glycemia, insulin resistance, progesterone, testosterone, and high-sensitivity C-reactive protein (hs-CRP)) were evaluated before (T0) and after (T1) the LI. After the LI, there were improvements in: body mass index (kg/m2: T0 = 26.0 ± 5.0, T1 = 25.5 ± 4.7; p = 0.035); diet (Mediet score: T0 = 6.9 ± 2.3, T1 = 8.8 ± 2.2; p < 0.001); PAL (MET-min/week: T0 = 647 ± 547, T1 = 1043 ± 564; p < 0.001); VO2max (mL·min-1·kg-1: T0 = 30.5 ± 5.8, T1 = 33.4 ± 6.8; p < 0.001); signs of diastolic dysfunction (participants: T0 = 15, T1 = 10; p = 0.007); AS-DNN/5 min (ms: T0 = 50.6 ± 14.4, T1 = 55.3 ± 16.7; p = 0.032); 24 hLF (ms2: T0 = 589 ± 391, T1 = 732 ± 542; p = 0.014); glycemia (mg/dL: T0 = 100.8 ± 11.4, T1 = 91.7 ± 11.0; p < 0.001); insulin resistance (HOMA-IR score: T0 = 2.07 ± 1.54, T1 = 1.53 ± 1.11; p = 0.005); testosterone (ng/mL: T0 = 0.34 ± 0.27, T1 = 0.24 ± 0.20; p = 0.003); hs-CRP (mg/L: T0 = 2.18 ± 2.14, T1 = 1.75 ± 1.74; p = 0.027). The other parameters did not change. Despite the home-confinement, LI based on exercise and nutrition improved cardiometabolic health in BCSs.

Differences between Community - and Hospital - acquired urinary tract infections in a tertiary care hospital.

The aim of this retrospective study was to highlight the differences in antibiotic resistance between Hospital-acquired and Community-acquired urinary tract infections (UTIs). Antimicrobial UTIs resistance data were collected from March 2011 to March 2018. Uropathogens were identified from 41,715 patients using routine laboratory methods. Differences in antibiotic resistance between Hospital and Community (non-hospitalized) patients were statistically validated. Odds ratio (OR) and p-values was used to determine whether a particular exposure (hospitalization) was a risk factor for a particular outcome (higher antibiotic resistance). We reported a general increase of unnecessary urine cultures in both community and hospital patients. The most representative microorganism isolated from Community (58.2%) and Hospital (47.6%) was E. coli. UTIs causative bacteria in hospitalized patients was more than twice as resistant to Trimetoprim/sulphamethoxazole (OR 2.26) and Imipenem (OR 2.56), for Gram-positive and Gram-negative, respectively, than in Community patients. Nitrofurantoin was the only agent without differences in resistance rate between community and hospital UTIs. Therefore, physicians could use it as a definitive therapy for uncomplicated cystitis and as a prophylactic agent for recurrent uncomplicated cystitis. With this work we provided a general protocol applicable by physicians to select the most suitable, if necessary, UTIs empiric treatment.

A three-year study entailing molecular characterization and epidemiology of Clostridium difficile in an Italian tertiary care hospital.

In Italy, there are limited studies on the molecular epidemiology of Clostridium difficile, possibly due to insufficient laboratory diagnostic capacity, low awareness and lack of high-quality surveillance systems. The aim of this study was to evaluate the diffusion of C. difficile in a tertiary care hospital and to genotype all the collected strains in order for hospital staff to take corrective action. All specimens were subjected to a CDI diagnostic algorithm. This included highly specific toxin PCRs and multilocus sequence typing (MLST) to obtain clear, unequivocal genotypization. During a three-year study period, as part of routine C. difficile testing, 711 stool samples were collected from 522 patients to detect the presence of toxigenic genes. After testing, 106 different samples were identified as toxigenic. The proportions of non-toxigenic and toxigenic isolates were respectively 8.7% (62/711) and 14.9% (106/711). The most infection findings in wards for toxigenic strains were in Internal Medicine (56), followed by Neurology (11) and Gastroenterology (11). Three novel sequence types (STs) were found. The two most prevalent STs in wards were clade 1 ST-378 (40) and clade 1 ST-379 (33). Other healthcare-acquired strains were clade 4 ST-37 (11) and clade 5 ST-11 (7). Two STs, namely clade 3 ST-5 (10) and clade 1 ST-380 (5), were isolated among external patients. To prevent an increase in outbreak probability, an active surveillance programme combined with proper hand hygiene, environmental cleaning and contact precautions should be implemented.

A Real-World Setting Study: Which Glucose Meter Could Be the Best for POCT Use? An Easy and Applicable Protocol During the Hospital Routine.

The aim of this retrospective study is to evaluate the reliability and robustness of six glucose meters for point-of-care testing in our wards using a brand-new protocol. During a 30-days study period a total of 50 diabetes patients were subjected to venous blood sampling and glucose meter blood analysis. The results of six glucose meters were compared with our laboratory reference assay. GlucoMen Plus (Menarini) with the 82% of acceptable results was the most robust glucose meter. Even if the Passing-Bablok analysis demonstrates the presence of constant systematic errors and the Bland-Altman test highlighted a possible overestimation, the surveillance error grid analysis showed that this glucose meter can be used safely. We proved that portable glucose meters are not always reliable in routinely clinical settings.

Retrospective analysis of nosocomial infections in an Italian tertiary care hospital.

Nosocomial infections are one of the leading causes of morbidity and mortality in hospitalized patients. Studies of their prevalence in single institutions can reveal trends over time and help to identify risk factors. The aim of this study was to investigate the nosocomial infections trend and identify the prevalence of predominant bacterial microorganisms and their drug resistance patterns in an Italian tertiary care hospital. Infections were classified according to the Centres for Disease Control and Prevention definitions. A retrospective study was carried out from March 2011 to June 2014, based on the bacterial isolate reports of a hospital located in Central Italy. During the 40-month study period, a total of 1547 isolates were obtained from 1046 hospitalized patients and tested for their antibiotic sensitivity. The most common isolates belonged to the Enterobacteriaceae family (61.7%), followed by Enterococcus species (12.4%), Pseudomonas species (10.7%) and S. aureus (10.0%). The incidence density rate of nosocomial infections was 7.4 per 1000 patient days, with a significant difference among the 3 annual infection rates (P<0.001). The highest infection prevalence rate was found in Internal Medicine Unit (41.3%), followed by Intensive Care Units (12.4%), Surgical Units (9.0%,) and Cardiology (7.1%).

Listeria monocytogenes meningitis in an immunocompromised patient.

This report describes a case of meningitis caused by Listeria monocytogenes in a stem cell transplant recipient on immunosuppressive therapy for cutaneous chronic graft-versus host disease. A 59-year-old woman had undergone allogeneic stem cell transplantation (from a matched unrelated donor) 13 months previously for chronic lymphocytic leukemia. She was on regular hematologic follow-up. Though her previous malignancy has been in remission, she was immunosuppressed due to the pharmacological treatment. We describe a meningitis caused by a typical food-borne pathogen, dangerous in patients with impaired cell-mediated immunity. Moreover the bacterium had a multidrug resistance, a rare characteristic in clinical listeriosis. Rapid diagnosis and treatment are key factors in these cases. We chose ampicillin and rifampicin that allowed a complete resolution of the clinical manifestations.

Interplay between 20S proteasomes and prion proteins in scrapie disease.

Scrapie is a transmissible spongiform encephalopathy affecting the central nervous system in sheep. The key event in such neurodegeneration is the conversion of the normal prion protein (PrP(C)) into the pathological isoform (PrP(Sc)). Misfolded prion proteins are normally degraded by the proteasome. This work, analyzing models of scrapie disease, describes the in vivo relationship between the proteasome and prions. We report that the disease is associated with an increase of proteasome functionality, most likely as a means of counteracting the increased levels of oxidative stress. Here, we show that prions coprecipitate with the 20S proteasome and that they colocalize within the same neuron, thus raising the possibility that PrP interacts with the proteasome in both normal and diseased brain, affecting substrate trafficking and proteasome functionality. This interaction, inducing proteasome activation, leads to different neuronal alterations and triggers apoptosis. Furthermore, testing the effects of isolated PrP(C) on purified 20S proteasomes, we obtain a concentration- and proteasome composition-dependent decrease in the complex activity.

Detection of typical and atypical bovine spongiform encephalopathy and scrapie prion strains by prion protein motif-grafted antibodies.

To evaluate further the reactivity of prion-specific monoclonal antibodies containing the 89-112 or 136-158 prion protein (PrP) polypeptides, immunoprecipitations were performed on brain extracts from Italian bovines, sheep and goats with transmissible spongiform encephalopathies. No binding of IgG 89-112 or IgG 136-158 to PrP in normal brain extracts was detected. Conversely, both reagents immunoprecipitated PrP from bovine and bovine amyloidotic spongiform encephalopathies, and from typical and atypical scrapie brain extracts. The immunoprecipitated PrP bands mirrored the Western blot (WB) profile of the different prion strains, indicating universal affinity of two independent PrP regions for disease-associated PrP conformers regardless of species source and strain properties. Immunoprecipitation with motif-grafted antibodies increased the sensitivity of conventional detection methods based on centrifugation followed by WB, which was confirmed by assay of diluted samples using both methods. These reagents or derivative molecules may thus find broad applications in prion detection and research.

Biosensor-based screening method for the detection of aflatoxins B1-G1.

Aflatoxins are extremely toxic metabolites from Aspergillus species that can adulterate a wide range of human foodstuff. Herein, we propose a novel assay designed as an analytical test for aflatoxin B1 and G1 (AFB1 and AFG1, respectively) that could represent an alternative screening technique for this class of mycotoxins. The approach for the determination of these toxins is based on surface plasmon resonance using neutrophil porcine elastase as a "bait" for these aflatoxins. The selection and optimization of the analytical procedure involved a preliminary investigation on the type of inhibition by AFB1: the level of the protease inhibition exerted by AFB1 depended upon the incubation time and the concentration of the binding partners, showing the competitiveness and the reversibility of the inhibition. A posteriori, the nature of the interaction granted a rapid analysis, a single detection test requiring only a few minutes. For the development of the assay, the experimental conditions were evaluated and optimized with both calibration solution and aflatoxin-spiked samples. To apply this method to aflatoxin-contaminated maize, a rapid solid-phase extraction treatment was developed. The proposed assay for AFB1 and AFG1 was validated by comparison with both a chromatographic reference method and a standard enzyme linked immunosorbent assay procedure. This enzyme-based biosensor represents a new approach for the detection of aflatoxins based on the reversible interaction between a blocked macromolecule and a soluble ligand, having the major advantages in the relative rapidity, the reusability of the capturing surface, and low cost per single test.

Binding of aflatoxins to the 20S proteasome: effects on enzyme functionality and implications for oxidative stress and apoptosis.

Aflatoxins (AF) are contaminants of improperly stored foods; they are potent genotoxic and carcinogenic compounds, exerting their effects through damage to DNA. They can also induce mutations that increase oxidative damage. The goal of this study was to evaluate the possibility that a third mechanism could be involved in the carcinogenic action of aflatoxins, namely, direct binding to key enzymes involved in the regulatory pathways of the cell cycle, thereby modulating enzyme functionality. The 20S constitutive and immunoproteasome peptidase and proteolytic activities were assayed in the presence of aflatoxins B1, G1 and M1. All three toxins activated multiple peptidase activities of the proteasome. Aflatoxin (AF) M1 was the most potent activator of proteasome activity, while the constitutive 20S proteasome was specifically stimulated by AFG1. Furthermore, the effects of AFB1 on cultured hepatoma cells were investigated and the various proteasomal activities determined with cell lysates were differently affected. Taking into account the key role of the proteasome in cellular defense against oxidative stress, the carbonyl group content and the activities of antioxidant enzymes in cell lysates were analyzed. The proapoptotic effect of AFB1 was also investigated by measuring caspase-3 activity and cellular levels of p27 and IkappaBalpha.

Prion protein potentiates acetylcholine release at the neuromuscular junction.

Cellular prion protein (PrP(c)), the normal isoform of the pathogenic peptide (PrP(sc)) responsible of the transmissible spongiform encephalopaties (TSEs), is present in many neural tissues, including neuromuscular junctions (NMJ). To analyze if this protein could influence the synaptic transmission, we performed an electrophysiological approach to study the effect of cellular prion protein on a mammalian neuromuscular junction. The loose patch clamp (LPC) technique enables the study of the whole preparation including the pre- and the post-synaptic domains. In a mouse phrenic-diaphragm preparation, nanomolar concentrations of cellular prion protein were able to induce a very striking potentiation of the acetylcholine (ACh) release. The effect was mainly pre-synaptic with an increase of the amplitude of the miniature end-plate currents, probably calcium dependent. Moreover, an apparent facilitation of the synaptic transmission was noted. The results clearly indicate that cellular prion protein may play a key role in the function of the neuromuscular junction.