Novel cell-based assays identify new metabolic targets to block Plasmodium falciparum transmission

La forma più pericolosa e mortale di malaria nell’uomo è causata dal parassita Plasmodium falciparum. Il parassita è trasmesso all’uomo dalla femmina della zanzara del genere Anopheles, che inietta gli sporozoiti nel sangue durante il suo pasto di sangue. Queste forme extracellulari migrano velocemente nel fegato attraverso il circolo ematico. Ogni sporozoita che invade un epatocita si divide mitoticamente e si differenzia in migliaia di merozoiti epatici che, rilasciati, invadono gli eritrociti, originando il ciclo asessuato intraeritrocitario. Questo ciclo, della durata di circa 48 ore, è responsabile dei sintomi clinici causati dall’infezione del parassita malarico. Nel sangue, alcune forme intra-eritrocitiche si differenziano, con un meccanismo ancora poco conosciuto, in gametociti maschili e femminili, le forme sessuali del parassita. All’interno dell’eritrocita, il parassita che ha intrapreso il differenziamento sessuale si sviluppa attraverso cinque stadi di maturazione che complessivamente durano circa 12 giorni. I gametociti maturi (stadio V), se risucchiati dalla zanzara Anopheles durante il suo pasto di sangue, si sviluppano in gameti all’interno del suo stomaco. Dalla fusione di un gamete femminile e uno maschile si forma uno zigote, il quale si differenzia in un oocinete che attraversa la parete dello stomaco e si trasforma in oocisti nell’emocele dell’insetto. Da questa oocisti sono rilasciati gli sporozoiti che migrano nelle ghiandole salivari e che verranno poi inoculati nell’ospite umano al successivo pasto di sangue. I gametociti di P. falciparum sono i responsabili della trasmissione del parassita dall’ospite umano alla zanzara. Tutti i farmaci ad oggi conosciuti sono utilizzati per curare i sintomi della malattia e quindi sono volti a eliminare le forme asessuate del parassita; l’unico farmaco ad oggi utilizzato contro i gametociti maturi di P. falciparum è la primachina. La carenza di farmaci contro i gametociti è in parte dovuta alla mancanza di un saggio cellulare veloce, quantitativo e riproducibile in grado di testare l’effetto di diverse librerie di composti sui gametociti. In parte l’assenza di tali saggi è dovuta al fatto che i gametociti maturi di P. falciparum sono stati fino ad oggi considerati cellule apparentemente quiescenti, con un metabolismo rallentato rispetto a quanto osservato per i parassiti asessuati e per i gametociti immaturi, rendendo difficile la misurazione dell’effetto di composti su questo stadio del parassita. Quest’ultima osservazione deriva dal fatto che i gametociti maturi sono spesso insensibili ai farmaci attivi contro le forme asessuate del parassita e contro i gametociti immaturi. Di conseguenza è necessario identificare vie metaboliche attive nei gametociti maturi come target per nuovi farmaci. Un’altra importante caratteristica dei gametociti di P. falciparum è la difficoltà nel valutare, tramite analisi morfologica, se siano vivi o morti dopo trattamento farmacologico in vitro. Nell’ambito di queste problematiche abbiamo sviluppato diversi saggi che abbiamo utilizzato per valutare la capacità di diversi composti di eliminare i gametociti. L'individuazione di nuovi farmaci o sinergie di farmaci capaci di agire contro i gametociti maturi di P. falciparum ha sottolineato l'esistenza di vie metaboliche attive in questi stadi, il cui studio approfondito può rappresentare un punto di partenza per lo sviluppo di nuovi trattamenti anti-trasmissione della malaria

Improvement of Biomethane Production from Organic Fraction of Municipal Solid Waste (OFMSW) through Alkaline Hydrogen Peroxide (AHP) Pretreatment

The organic fraction resulting from the separate collection of municipal solid waste (OFMSW) is an abundant residue exploitable for biofuel production. Anaerobic digestion (AD) is one of the most attractive technologies for the treatment of organic wastes thanks to the generation of biogas with a high methane content. However, because of its complex composition, the direct digestion of OFMSW can be less effective. To overcome these difficulties, many pretreatments are under development. In this work, the efficacy of alkaline hydrogen peroxide (AHP) oxidation was assessed for the first time as a pretreatment of OFMSW to enhance its anaerobic biodegradability. In this regard, many AHP batch tests were executed at pH 9 and by changing the peroxide dosages up to 1 gH2O2/gCOD, under room temperature and pressure conditions. Afterwards, biomethane potential tests (BMP) were conducted to evaluate the performance of anaerobic digestion both on raw and pretreated OFMSW. The pretreatment tests demonstrated that AHP induces only a weak reduction in the organic load, reaching a maximum COD removal of about 28%. On the other hand, notable productions of volatile fatty acids (VFA) were found. In fact, by applying a peroxide dose of just 0.025 gH2O2/gCOD, there was a doubling in VFA concentration, which increased by five times with the highest H2O2 amount. These results indicate that AHP mainly causes the conversion of complex organic substrates into easily degradable compounds. This conversion made it possible to achieve much better performance during the BMP tests conducted with the pretreated waste compared to that carried out on fresh OFMSW. Indeed, a low methane production of just 37.06 mLCH4/gTS was detected on raw OFMSW. The cumulated CH4 production in the pretreated samples increased in response to the increase in H2O2 dosage applied during AHP. Maximum specific productions of about 463.7 mLCH4/gTS and 0.31 LCH4/gCODremoved were calculated on mixtures subjected to AHP. On these samples, the satisfactory evolution of AD was confirmed by the process parameters calculated by modeling the cumulated CH4 curves through a new proposed formulation of the Gompertz equation

An Artificial Intelligence Based Method For Optimized Warehouse Storage Allocation

Order picking is a major driver of warehouse operation costs. With the objective of minimizing the time and cost required for picking customer orders in large warehouses, this paper presents an artificial intelligence (AI)-based algorithm for optimized warehouse storage allocation. Specifically, the linear upper confident bound (linUCB) algorithm, a contextual multi-arm bandit algorithm, is used to select storage locations for incoming products, that are optimal with regard to the expected stock removal. To facilitate the perception and decision making of the agent, dimensionality reduction by means of clustering is employed, enabling the linUCB agent to interact with a low dimensional representation of the warehouse. For training, we present a reward function that evaluates the agent’s decision making based on the actual cost of picking a product from the warehouse. Because the calculation of the reward metric is exclusively based on actually incurred picking distances, human bias in the design of the reward function is minimized. In a practical case study, the suggested method is applied to a real warehouse layout with 4,650 storage locations, two picking areas and 30 different product categories. For the training and evaluation of the method a warehouse simulation is used. The performance of the linUCB agent is benchmarked against a conventional ABC allocation strategy. A comparison shows that the artificial intelligence-based storage allocation outperforms the ABC-method

The proposal of a clinical protocol to assess central and peripheral fatigue in myotonic dystrophy type 1

DM1 is an autosomal-dominant disorder characterized by muscle weakness, myotonia, and multisystemic involvement. According to current literature fatigue and daytime sleepiness are among the main symptoms of DM1. Oxidative stress has been proposed to be one of the pathogenic factors of fatigue consequent to DM1. In this study, we investigated the dimensions of experienced fatigue and  physiological fatigue in a sample of 26 DM1 patients (17 males, 9 females, mean age 41.6 years, SD±12.7); experienced fatigue has been studied through Fatigue Severity Scale (FSS), and physiological fatigue was measured through an intermittent incremental exercise of the forearm muscles using a myometer; oxidative stress balance markers trend during aerobic exercise test have been collected. The occurrence of central fatigue in the sample means that central activation worsens during the motor contraction; interestingly FSS score was significantly correlated to MVC (before and after the effort, r-before=-0.583, p<0.01, r-after= -0.534, p<0.05), and to motor disability measured by MRC (r=-0.496, p<0.05); moreover we found a strong tendency towards significance in the association to lactate baseline (r=0.378, p=0.057).Results are discussed to define whether or not, based on clinical and laboratory grounds, such exercise training protocol may be suitable for proper management of DM1 patients; proper assessment of fatigue should be included in algorithms for data collection in DM1 patient registries

Biomolecules of Muscle Fatigue in Metabolic Myopathies

Metabolic myopathies are a group of genetic disorders that affect the normal functioning of muscles due to abnormalities in metabolic pathways. These conditions result in impaired energy production and utilization within muscle cells, leading to limitations in muscle function with concomitant occurrence of related signs and symptoms, among which fatigue is one of the most frequently reported. Understanding the underlying molecular mechanisms of muscle fatigue in these conditions is challenging for the development of an effective diagnostic and prognostic approach to test targeted therapeutic interventions. This paper outlines the key biomolecules involved in muscle fatigue in metabolic myopathies, including energy substrates, enzymes, ion channels, and signaling molecules. Potential future research directions in this field are also discussed

Detection of Plasmodium falciparum male and female gametocytes and determination of parasite sex ratio in human endemic populations by novel, cheap and robust RTqPCR assays

The presence of Plasmodium falciparum gametocytes in peripheral blood is essential for human to mosquito parasite transmission. The detection of submicroscopic infections with gametocytes and the estimation of the gametocyte sex ratio are crucial to assess the human host potential ability to infect mosquitoes and transmit malaria parasites

Physical exercise and oxidative stress in muscular dystrophies: is there a good balance? Exercise and oxidative stress in MDs

The effect of oxidative stress on muscle damage inducted by physical exercise is widely debated. It is generally agreed that endurance and intense exercise can increase oxidative stress and generate changes in antioxidant power inducing muscle damage; however, regular and moderate exercise can be beneficial for the health improving the antioxidant defense mechanisms in the majority of cases. Growing evidences suggest that an increased oxidative/nitrosative stress is involved in the pathogenesis of several muscular dystrophies (MDs). Notably, physical training has been considered useful for patients with these disorders. This review will focus on the involvement of oxidative stress in MDs and on the possible effects of physical activities to decrease oxidative damage and improve motor functions in MDs patients

Muscle fatigue and exercise-related biomarkers in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder affecting motor neurons. The complex etiopathogenetic mechanism of ALS can lead to extensive alterations, including cortical changes, neuroinflammation, and changes in muscular structure. These ALS-derived alterations may contribute to fatigue, a symptom severely impacting patients’ quality of life that is commonly associated with muscular exercise. Intriguingly, muscular exercise can be at once a promoter of motor neuron degeneration in predisposed patients as well as an effective non-pharmacological treatment of ALS. To fully disclose its therapeutic potential, muscular exercise must be tailored to patients’ phenotypes, balancing potential benefits and risks that are unique to each ALS case. Biomarkers of muscular fatigue, with their potential for insight into inflammation and oxidation, can be used to ensure that the intensity of physical activity remains below the threshold level beyond which exercise might become harmful. In this review, the authors explore the concept of fatigue in ALS patients, focusing on fatigue generation, definition, detection, quantification, and treatment. The study discusses the most important fatigue biomarkers, putting them in relation to the mechanism of fatigue generation and with monitoring of muscular exercise as a possible treatment of fatigue

Real-time PCR assays for detection and quantification of early P. falciparum gametocyte stages

Introduction The use of reverse transcription, quantitative qRT-PCR assays for detection and quantification of late gametocyte stages has revealed the high transmission capacity of the human malaria parasite, Plasmodium falciparum. A full understanding how the parasite adjusts its transmission in response to varying in-host environmental conditions during natural infections requires simultaneous quantification of early and late gametocytes. Here, we describe qRT-PCR assays that are specific for detection and quantification of early-stage gametocytes of P. falciparum. Methods The assays are based on expression of known early gametocyte genes (pfpeg4, pfg27, pfge1, pfge3 and pfgexp5). The specificity of the qRT-PCR assays was tested using purified stage II and stage V gametocytes. These validated assays were used with qRT-PCR assays targeting late stage (pfs25) and all-stage (pfs16) gametocyte-specific transcripts to quantify gametocytes in natural P. falciparum infections and in a controlled human clinical infection study. Results The relative expression of pfpeg4, pfg27 and pfge3, but not of pfge1 and pfgexp5, was significantly higher in purified stage II compared to stage V gametocytes, indicating early gametocyte specificity. In natural infections, 71.2% of individuals had both early and late gametocyte transcripts (pfpeg4/pfg27 plus pfs25), 12.6% harboured only early gametocytes transcripts (pfpeg4/pfg27), and 15.2% had only late gametocytes transcripts (pfs25). In natural infections, the limit of detection was equivalent to 190 and 390 gametocytes/mL blood for pfpeg4 and pfg27, respectively. In infected volunteers, transcripts of pfpeg4 and pfg27 were detected shortly after the onset of blood stage infection, demonstrating the specificity of the assays. Conclusion The pfpeg4 and pfg27 qRT-PCR assays can be used specifically to quantify circulating immature gametocytes. Quantification of early gametocytes will improve understanding of epidemiological processes that modulate P. falciparum transmission and enhance the evaluation of transmission blocking interventions

Excessive daytime sleepiness in myotonic dystrophy: a narrative review

IntroductionExcessive daytime sleepiness (EDS) is a common and debilitating symptom in both forms of myotonic dystrophy (DM), significantly impacting patients’ quality of life. The review focuses on the purpose of examining the current understanding of EDS in these conditions, the difficulty in correctly accessing it, the recent findings related to its etiology and prevalence, and a summary of potential therapeutic implications.MethodsWe conducted a comprehensive search through PubMed, selecting studies that provided significant insights into the mechanisms, prevalence, and management of EDS in DM1 and DM2.Results and discussionEDS is highly prevalent in both DM1 and DM2. Polysomnographic studies have revealed prominent dysregulation of REM sleep in DM1, suggesting a possible narcoleptic-like phenotype and alterations in NREM sleep that contributes to daytime sleepiness. Other factors have been proposed to explain EDS in DM1, including dysregulation of the sleep-wake circadian rhythm through nocturnal actigraphy analysis. The central origin of EDS is increasingly delineated supported by serotonin and orexin pathways dysfunction, and recent neuroradiological findings showing that in DM1 hippocampus volume was positively correlated with self-reported fatigue and somnolence. Sleep-disordered breathing and respiratory dysfunctions are prevalent in DM, their direct correlation with EDS remains complex and inconclusive, but respiratory evaluation should be recommended if obstructive sleep apneas or respiratory muscle dysfunctions are suspected. Drug interventions, such as modafinil and mexiletine, have shown promise in managing excessive daytime sleepiness and reducing myotonia without significant cardiac conduction effects. Enhancing EDS management in myotonic dystrophy is key to improving overall patient well-being