The Century-Long Journey of Peptide-Based Drugs

The pioneering medical application of peptides as therapeutics began approximately a century ago; however, they remain clinically relevant candidates garnering more attention on the drug development agenda [...].

Polyhydroxyalkanoates production in purple phototrophic bacteria ponds: A breakthrough in outdoor pilot-scale operation

The versatile capacity of purple phototrophic bacteria (PPB) for producing valuable bioproducts has gathered renewed interest in the field of resource recovery and waste valorisation. However, greater knowledge regarding the viability of applying PPB technologies in outdoor, large-scale systems is required. This study assessed, for the first time, the upscaling of the phototrophic polyhydroxyalkanoate (PHA) production technology in a pilot-scale system operated in outdoor conditions. An integrated system composed of two up-flow anaerobic sludge blanket (UASB) reactors (for fermentation of wastewater with molasses), and two high-rate algal ponds retrofitted into PPB ponds, was operated in a wastewater treatment plant under outdoor conditions. UASB's adaptation to the outdoor temperatures involved testing different operational settings, namely hydraulic retention times (HRT) of 48 and 72 h, and molasses fermentation in one or two UASBs. Results have shown that the fermentation of molasses in both UASBs with an increased HRT of 72 h was able to ensure a suitable operation during colder conditions, achieving 3.83 ± 0.63 g CODFermentative Products/L, compared to the 3.73 ± 0.85 g CODFermentative Products/L achieved during warmer conditions (molasses fermentation in one UASB; HRT 48 h). Furthermore, the PPB ponds were operated under a light-feast/dark-aerated-famine strategy and fed with the fermented wastewater and molasses from the two UASBs. The best PHA production was obtained during the summer of 2018 and spring of 2019, attaining 34.7 % gPHA/gVSS with a productivity of 0.11 gPHA L-1 day-1 and 36 % gPHA/gVSS with a productivity of 0.14 gPHA L-1 day-1, respectively. Overall, this study showcases the first translation of phototrophic PHA production technology from an artificially illuminated laboratory scale system into a naturally illuminated, outdoor, pilot-scale system. It also addresses relevant process integration aspects with UASBs for pre-fermenting wastewater with molasses, providing a novel operational strategy to achieve photosynthetic PHA production in outdoor full-scale systems.

Differential effects of the venoms of Russell's viper and Indian cobra on human myoblasts

Local tissue damage following snakebite envenoming remains a poorly researched area. To develop better strategies to treat snakebites, it is critical to understand the mechanisms through which venom toxins induce envenomation effects including local tissue damage. Here, we demonstrate how the venoms of two medically important Indian snakes (Russell's viper and cobra) affect human skeletal muscle using a cultured human myoblast cell line. The data suggest that both venoms affect the viability of myoblasts. Russell's viper venom reduced the total number of cells, their migration, and the area of focal adhesions. It also suppressed myogenic differentiation and induced muscle atrophy. While cobra venom decreased the viability, it did not largely affect cell migration and focal adhesions. Cobra venom affected the formation of myotubes and induced atrophy. Cobra venom-induced atrophy could not be reversed by small molecule inhibitors such as varespladib (a phospholipase A2 inhibitor) and prinomastat (a metalloprotease inhibitor), and soluble activin type IIb receptor (a molecule used to promote regeneration of skeletal muscle), although the antivenom (raised against the Indian 'Big Four' snakes) has attenuated the effects. However, all these molecules rescued the myotubes from Russell's viper venom-induced atrophy. This study demonstrates key steps in the muscle regeneration process that are affected by both Indian Russell's viper and cobra venoms and offers insights into the potential causes of clinical features displayed in envenomed victims. Further research is required to investigate the molecular mechanisms of venom-induced myotoxicity under in vivo settings and develop better therapies for snakebite-induced muscle damage.

Antibacterial and Antiviral Properties of Chenopodin-Derived Synthetic Peptides

Antimicrobial peptides have been developed based on plant-derived molecular scaffolds for the treatment of infectious diseases. Chenopodin is an abundant seed storage protein in quinoa, an Andean plant with high nutritional and therapeutic properties. Here, we used computer- and physicochemical-based strategies and designed four peptides derived from the primary structure of Chenopodin. Two peptides reproduce natural fragments of 14 amino acids from Chenopodin, named Chen1 and Chen2, and two engineered peptides of the same length were designed based on the Chen1 sequence. The two amino acids of Chen1 containing amide side chains were replaced by arginine (ChenR) or tryptophan (ChenW) to generate engineered cationic and hydrophobic peptides. The evaluation of these 14-mer peptides on Staphylococcus aureus and Escherichia coli showed that Chen1 does not have antibacterial activity up to 512 µM against these strains, while other peptides exhibited antibacterial effects at lower concentrations. The chemical substitutions of glutamine and asparagine by amino acids with cationic or aromatic side chains significantly favoured their antibacterial effects. These peptides did not show significant hemolytic activity. The fluorescence microscopy analysis highlighted the membranolytic nature of Chenopodin-derived peptides. Using molecular dynamic simulations, we found that a pore is formed when multiple peptides are assembled in the membrane. Whereas, some of them form secondary structures when interacting with the membrane, allowing water translocations during the simulations. Finally, Chen2 and ChenR significantly reduced SARS-CoV-2 infection. These findings demonstrate that Chenopodin is a highly useful template for the design, engineering, and manufacturing of non-toxic, antibacterial, and antiviral peptides.

Dual antibacterial mechanism of [K4K15]CZS-1 against Salmonella Typhimurium: a membrane active and intracellular-targeting antimicrobial peptide

Salmonella genus is a leading cause of food-borne infections with strong public health impact and economic ramifications. The development of antimicrobial resistance added complexity to this scenario and turned the antibiotic drug discovery into a highly important challenge. The screening of peptides has served as a successful discovery platform to design new antibiotic candidates. Motivated by this, the antimicrobial and cytotoxic properties of three cruzioseptins against Salmonella Typhimurium and RAW 264.7 murine macrophage cells, respectively, were investigated. [K4K15]CZS-1 was the most potent antimicrobial peptide identified in the screening step with a minimum inhibitory concentration (MIC) of 16 μg/mL (7.26 μM) and moderate cytotoxicity. From a structural point of view, in vitro and in silico techniques evidenced that [K4K15]CZS-1 is a α-helical cationic antimicrobial peptide. In order to capture mechanistic details and fully decipher their antibacterial action, we adopted a multidimensional approach, including spectroscopy, electron microscopy and omics analysis. In general lines, [K4K15]CZS-1 caused membrane damage, intracellular alterations in Salmonella and modulated metabolic pathways, such as the tricarboxylic acid (TCA) cycle, fatty acid biosynthesis, and lipid metabolism. Overall, these findings provide deeper insights into the antibacterial properties and multidimensional mode of action of [K4K15]CZS-1 against Salmonella Typhimurium. In summary, this study represents a first step toward the screening of membrane-acting and intracellular-targeting peptides as potential bio-preservatives to prevent foodborne outbreaks caused by Salmonella.

Partial segmental thrombosis of the corpus cavernosum following Russell's viper bite

Snakebite envenoming (SBE) is common in rural communities living in tropical regions that often have fragile and/or overwhelmed healthcare systems. The complex scenarios around SBE lead to a high number of deaths, disabilities, and long-term consequences in patients. Russell's viper (Daboia russelii) is one of the most medically important snake species in India, which causes devastating pathological conditions characterised by a wide range of clinical manifestations. This broad spectrum of symptoms requires additional therapeutic interventions beyond the classical antivenom administration. Hence, positive outcomes for patients affected by SBE can be achieved with a better understanding of previous experiences describing clinical manifestations and various therapeutic interventions including for rare and underreported conditions. Here, we report an SBE victim who developed partial segmental thrombosis in the corpus cavernosum following Russell's viper envenomation and its diagnostic and treatment approaches. The patients received 180 ml of antivenom to resolve the abnormalities in their haematological parameters. Despite antivenom treatment, they developed severe pain in their genital region, and subsequent ultrasound and magnetic resonance imaging confirmed segmental thrombosis in the corpus cavernosum, which required supportive measures. The treatment using low molecular weight heparin, rivaroxaban and non-steroidal anti-inflammatory drugs resolved segmental thrombosis. In conclusion, this case report exemplifies the development of a rare segmental thrombosis in corpus cavernosum and how the medical, scientific, and general community can benefit from documenting clinical manifestations, medically relevant insights into patient care and the management of underreported complications.

Ammonia impact on the selection of a phototrophic - chemotrophic consortium for polyhydroxyalkanoates production under light-feast / dark-aerated-famine conditions

Phototrophic polyhydroxyalkanoate (PHA) production is an emerging technology for recovering carbon and nutrients from diverse wastewater streams. However, reliable selection methods for the enrichment of PHA accumulating purple phototrophic bacteria (PPB) in phototrophic mixed cultures (PMC) are needed. This research evaluates the impact of ammonia on the selection of a PHA accumulating phototrophic-chemotrophic consortium, towards the enrichment of PHA accumulating PPB. The culture was operated under light-feast/dark-aerated-famine and winter simulated-outdoor conditions (13.2 ± 0.9 °C, transient light, 143.5 W/m2), using real fermented domestic wastewater with molasses as feedstock. Three ammonia supply strategies were assessed: 1) ammonia available only in the light phase, 2) ammonia always present and 3) ammonia available only during the dark-aerated-famine phase. Results showed that the PMC selected under 1) ammonia only in the light and 3) dark-famine ammonia conditions, presented the lowest PHA accumulation capacity during the light period (11.1 % g PHA/g VSS and 10.4 % g PHA/g VSS, respectively). In case 1), the absence of ammonia during the dark-aerated-famine phase did not promote the selection of PHA storing PPB, whereas in case 3) the absence of ammonia during the light period favoured cyanobacteria growth as well as purple sulphur bacteria with increased non-PHA inclusions, resulting in an overall decrease of phototrophic PHA accumulation capacity. The best PHA accumulation performance was obtained with selection under permanent presence of ammonia (case 2), which attained a PHA content of 21.6 % g PHA/g VSS (10.2 Cmmol PHA/L), at a production rate of 0.57 g PHA/L·day, during the light period in the selection reactor. Results in case 2 also showed that feedstock composition impacts the PMC performance, with feedstocks richer in more reduced volatile fatty acids (butyric and valeric acids) decreasing phototrophic performance and leading to acids entering the dark-aerated phase. Nevertheless, the presence of organic carbon in the aerated phase was not detrimental to the system. In fact, it led to the establishment of a phototrophic-chemotrophic consortium that could photosynthetically accumulate a PHA content of 13.2 % g PHA/g VSS (6.7 Cmmol PHA/L) at a production rate of 0.20 g PHA/L·day in the light phase, and was able to further increase that storage up to 18.5 % g PHA/g VSS (11.0 Cmmol PHA/L) at a production rate of 1.35 g PHA/L·day in the dark-aerated period. Furthermore, the light-feast/dark-aerated-famine operation was able to maintain the performance of the selection reactor under winter conditions, unlike non-aerated PMC systems operated under summer conditions, suggesting that night-time aeration coupled with the constant presence of ammonia can contribute to overcoming the seasonal constraints of outdoor operation of PMCs for PHA production.

Identifying key factors contributing to treatment costs for snakebite envenoming in private tertiary healthcare settings in Tamil Nadu, India

BACKGROUND

India suffers ~58,000 annual deaths due to snakebites. The 'Big Four' snakes (Russell's viper, Indian cobra, common krait, and saw-scaled viper) that are responsible for most bites cause diverse clinical effects. Delayed treatment increases the risk of serious complications and treatment costs. Although government hospitals offer free treatment for snakebites in India, most patients opt for private healthcare, which is an out-of-pocket expense as they often lack health insurance coverage. This study aims to analyse snakebite treatment costs in private tertiary care hospitals in Tamil Nadu, India and identifies the key factors contributing to treatment costs.

METHODOLOGY/PRINCIPAL FINDINGS

The treatment cost details for 913 snakebite victims were collected from 10 private tertiary care hospitals across Tamil Nadu. The data were classified into hospital, pharmacy, investigation, and laboratory costs, and analysed to determine various factors that contribute to the costs. The results demonstrate that the average treatment costs vary widely for different snakes. The hospital and pharmacy costs are higher than investigation and laboratory costs for all snakebites. Notably, Russell's viper bites cost significantly more than the bites from other snakes. Overall, the type of snake, nature of complications, specialist treatments required, and arrival time to hospitals were identified as some of the key factors for higher treatment costs.

CONCLUSIONS/SIGNIFICANCE

These data demonstrate that ~80% of snakebite patients can be treated with INR 100,000 (~GBP 1000 or USD 1200) or less. This study emphasises the urgent need to improve rural medical care by providing appropriate training for healthcare professionals and essential resources to facilitate early assessment of patients, administer the initial dose of antivenom and refer the patients to tertiary care only when needed. Moreover, the outcome of this study forms a basis for developing appropriate policies to regulate snakebite treatment costs and provide affordable medical insurance for vulnerable communities.

Discovery of a human monoclonal antibody that cross-neutralizes venom phospholipase A2s from three different snake genera

Despite the considerable global impact of snakebite envenoming, available treatments remain suboptimal. Here, we report the discovery of a broadly-neutralizing human monoclonal antibody, using a phage display-based cross-panning strategy, capable of reducing the cytotoxic effects of venom phospholipase A2s from three different snake genera from different continents. This highlights the potential of utilizing monoclonal antibodies to develop more effective, safer, and globally accessible polyvalent antivenoms that can be widely used to treat snakebite envenoming.

Intramuscular Bleeding and Formation of Microthrombi during Skeletal Muscle Damage Caused by a Snake Venom Metalloprotease and a Cardiotoxin

The interactions between specific snake venom toxins and muscle constituents are the major cause of severe muscle damage that often result in amputations and subsequent socioeconomic ramifications for snakebite victims and/or their families. Therefore, improving our understanding of venom-induced muscle damage and determining the underlying mechanisms of muscle degeneration/regeneration following snakebites is critical to developing better strategies to tackle this issue. Here, we analysed intramuscular bleeding and thrombosis in muscle injuries induced by two different snake venom toxins (CAMP-Crotalus atrox metalloprotease (a PIII metalloprotease from the venom of this snake) and a three-finger toxin (CTX, a cardiotoxin from the venom of Naja pallida)). Classically, these toxins represent diverse scenarios characterised by persistent muscle damage (CAMP) and successful regeneration (CTX) following acute damage, as normally observed in envenomation by most vipers and some elapid snakes of Asian, Australasian, and African origin, respectively. Our immunohistochemical analysis confirmed that both CAMP and CTX induced extensive muscle destruction on day 5, although the effects of CTX were reversed over time. We identified the presence of fibrinogen and P-selectin exposure inside the damaged muscle sections, suggesting signs of bleeding and the formation of platelet aggregates/microthrombi in tissues, respectively. Intriguingly, CAMP causes integrin shedding but does not affect any blood clotting parameters, whereas CTX significantly extends the clotting time and has no impact on integrin shedding. The rates of fibrinogen clearance and reduction in microthrombi were greater in CTX-treated muscle compared to CAMP-treated muscle. Together, these findings reveal novel aspects of venom-induced muscle damage and highlight the relevance of haemostatic events such as bleeding and thrombosis for muscle regeneration and provide useful mechanistic insights for developing better therapeutic interventions.

Indian Ornamental Tarantula (Poecilotheria regalis) Venom Affects Myoblast Function and Causes Skeletal Muscle Damage

Envenomation by the Indian ornamental tarantula (Poecilotheria regalis) is medically relevant to humans, both in its native India and worldwide, where they are kept as pets. Muscle-related symptoms such as cramps and pain are commonly reported in humans following envenomation by this species. There is no specific treatment, including antivenom, for its envenomation. Moreover, the scientific knowledge of the impact of this venom on skeletal muscle function is highly limited. Therefore, we carried out this study to better understand the myotoxic properties of Poecilotheria regalis venom by determining its effects in cultured myoblasts and in the tibialis anterior muscle in mice. While there was no effect found on undifferentiated myoblasts, the venom affected differentiated multinucleated myotubes resulting in the reduction of fusion and atrophy of myotubes. Similarly, intramuscular administration of this venom in the tibialis anterior muscle in mice resulted in extensive muscle damage on day 5. However, by day 10, the regeneration was evident, and the regeneration process continued until day 20. Nevertheless, some tissue abnormalities including reduced dystrophin expression and microthrombi presence were observed on day 20. Overall, this study demonstrates the ability of this venom to induce significant muscle damage and affect its regeneration in the early stages. These data provide novel mechanistic insights into this venom-induced muscle damage and guide future studies to isolate and characterise individual toxic component(s) that induce muscle damage and their significance in developing better therapeutics.

Neutrophil-mediated erythrophagocytosis following Russell's viper (Daboia russelii) bite

Snakebite envenomation is regarded as a high-priority neglected tropical disease by the World Health Organisation, as it results in significant loss of lives and permanent disabilities. Russell's viper is one of the snakes that causes morbidities, mortalities and disabilities in India. The clinical presentation of Russell's viper envenomation is characterised by local envenoming effects, tissue damage, venom-induced coagulopathy, neurotoxicity, and kidney injury. However, venom composition and its mechanisms of toxicity are highly variable even within snakes of the same species including Russell's viper. This variation in venom composition results in a broad range of clinical complications. Here we present a previously undocumented case of neutrophil-mediated erythrophagocytosis in a healthy 28-year-old female following Russell's viper bite. Systemic envenomation effects and bleeding abnormalities in this patient were corrected by the administration of polyvalent antivenom. Two days later, the patient developed progressive swelling and ecchymosis in the bitten limb. Observed abnormal limits within blood testing were followed up by a peripheral blood smear where it was found that 30% of neutrophils had phagocytosed erythrocytes as they were found within the cytoplasm. The patient underwent a fasciotomy for compartmental syndrome and received packed red cells and a course of corticosteroids. Following this treatment, the patient made a full recovery. This case report outlines a previously undocumented pathological event induced by Russell's viper envenomation, guiding diagnosis and treatment. Clinicians' knowledge of the mechanisms of toxicity of Russell's viper envenomation and its clinical manifestations are essential for improving the treatment of snakebites to achieve positive outcomes.

Ashes to eye: A skilled snake handler's experience with ophthalmic envenomation

With the continued growth of human populations, rural urbanisation and habitat degradation are on the rise, resulting in the displacement of native wildlife and an increase in human-wildlife conflicts. The presence of human habitation and waste often attracts rodents and thereby, snakes, leading to increased snake sightings in homes. To address this problem, snake handlers, who are volunteers that remove and relocate snakes away from human development areas, are called upon. However, snake removal is a high-risk task that poses a risk of envenomation, particularly when dealing with spitting snakes. Several cobra species have the ability to spit venom. If the venom enters a person's eye, it can result in ophthalmic envenomation, which can have serious consequences for their eyesight. Therefore, snake handlers should take precautions, wear suitable eye protection, and use appropriate tools to ensure their safety and that of the snake. In this case, an experienced snake handler was called to remove a spitting cobra, but they were ill-equipped. During the removal, the venom was sprayed across the handler's face, and some of it entered their eye, resulting in ophthalmic envenomation. The handler promptly irrigated their eye, but medical treatment was still necessary. This report highlights the risks and consequences of ophthalmic injury and the importance of wearing appropriate eye protection and taking due care when dealing with venomous species, particularly those that can spit venom. It serves as a reminder that accidents can happen at any time and experienced snake handlers are not exempt from the risks.

Rapid identification of bilateral adrenal and pituitary haemorrhages induced by Russell's viper envenomation results in positive patient outcome

The clinical management of snakebite envenomation (SBE) is challenging in many tropical and subtropical regions of developing countries due to the complex clinical manifestations and inadequate medical infrastructure. Some venomous snakes, such as the Indian Russell's viper (Daboia russelii) cause a wide range of rare complications in addition to their classical envenomation effects. In general, these uncommon complications are often misdiagnosed or not treated promptly due to a lack of awareness about these conditions. Thus, it is critical to report such complications to draw the attention of the healthcare and research communities to improve the clinical management and scientific research of SBE, respectively. Here, we report bilateral adrenal and pituitary haemorrhages in an SBE patient following a bite by Russell's viper in India. The initial symptoms included gum bleeding, swelling, axillary lymphadenopathy and clotting abnormalities. Despite the administration of antivenom, the patient presented palpitation, nausea, and abdominal pain, which were not recovered by combinational therapy with epinephrine and dexamethasone. Further infusion of antivenom did not address these issues and the patient displayed persistent hypotension, hypoglycaemia and hyperkalaemia suggesting an adrenal crisis. Inadequate secretion of corticosteroids was confirmed by laboratory tests, and imaging investigations revealed haemorrhages in both the adrenal and pituitary glands. The patient made a full recovery after treatment with hydrocortisone and thyroxine. This report adds to the growing evidence of rare complications induced by Russell's viper envenomations and it provides relevant guidance to diagnose and treat such complications in SBE victims.

The Effectiveness of Antibiotics in Managing Bacterial Infections on Bite Sites following Snakebite Envenomation

Snakebite envenomation (SBE) is a life-threatening medical emergency with a high mortality rate. Common secondary complications following SBE, such as wound infections, are significant due to their impact on worsening local tissue damage and causing systemic infection. Antivenoms are not effective to treat wound infections following SBE. Moreover, in several rural clinical settings, broad-spectrum antibiotics are often used without clear guidelines or based on limited laboratory data, resulting in undesirable side effects and exacerbated treatment costs. Therefore, robust antibiotic strategies should be developed to tackle this critical issue. Currently, there is limited information available on the bacterial profiles of SBE-induced infections and antibiotic susceptibility. Hence, it is essential to improve the knowledge of bacterial profiles and their antibiotic sensitivity in SBE victims to develop better treatment strategies. This study aimed to address this issue by examining the bacterial profiles of SBE victims with a specific focus on Russell's viper envenomation. The most frequently found bacteria in the bites of SBE victims were Staphylococcus aureus, Klebsiella sp., Escherichia coli, and Pseudomonas aeruginosa. Linezolid, clindamycin, colistin, meropenem, and amikacin were some of the most effective antibiotics for commonly grown bacteria in SBE victims. Similarly, ciprofloxacin, ampicillin, amoxiclave, cefixime, and tetracyclin were the least effective antibiotics for common bacteria found in the wound swabs of SBE victims. These data provide robust guidance for infection management following SBE and offer useful insights to aid in designing effective treatment protocols for SBE with serious wound infections in rural areas where laboratory facilities may not be readily available.

Russell's viper envenomation induces rectus sheath haematoma

Snakebite envenomation causes systemic and local manifestations, which result from the individual or synergistic actions of multiple venom components. The pathological hallmarks of medically important venomous snakes such as the Indian Russell's viper (Daboia russelii) are well known. Envenomation by Russell's viper is typically characterised by coagulopathies, muscular damage, nephrotoxicity, and neurotoxicity. However, recent reports have revealed several unusual complications that provide a better understanding of Russell's viper envenomation effects. To further strengthen this, here, we report a case of Russell's viper bite that induced acute abdominal pain, which was intensified on day two and conservatively treated under medical supervision. Both Fothergill and Carnett signs were positive for this patient. An ultrasound imaging revealed a dissimilar dense mass, and the abdominal computed tomography scan confirmed rectus sheath haematoma. The clinical management involved the administration of polyvalent antivenom, packed red blood cells, fresh frozen plasma, and platelets. The patient recovered gradually and was discharged from the hospital eight days after the bite. Overall, this case presentation shares an uncommon experience and adds new insights into the complex series of rare pathological events associated with Russell's viper bites in India. The scientific documentation of relatively infrequent entities based on an ongoing living assessment of medical experiences, for example, this rectus sheath haematoma, constitutes valuable guidance for an adequate diagnosis and timely treatment. Essential awareness among clinicians and further research on understanding the molecular relationship between Russell's viper venom and rectus sheath haematoma will improve patient outcomes and understanding of this condition, respectively.

A retrospective study of clinical and epidemiological characteristics of snakebite in Napo Province, Ecuadorian Amazon

BACKGROUND

Snakebite envenoming remains a relevant public health problem in tropical and subtropical countries. In Ecuador, this is particularly true in an area of great diversity like the Amazon region. Nevertheless, there is scarce information about epidemiological and clinical characteristics of these accidents in this area.

METHODS

This was a descriptive and retrospective study of snakebite cases treated at a tertiary hospital in the Napo Province, Ecuadorian Amazon, from 2015 to 2019. We collected sociodemographic and snakebite-related information, clinical aspects and the use of antivenom and antibiotics from medical records.

RESULTS

Information from 133 snakebite accidents was reviewed in this time period. Reports of snakebite envenoming decreased over the years. In total, 67% of those bitten were from nearby indigenous communities, which were the most affected groups. When a species was identified, Bothrops atrox was responsible for the highest number of cases registered. Local clinical manifestations were more frequent than systemic signs, in keeping with the typical effects produced by bothropic venoms. Additionally, data showed that more antivenom vials were given than those suggested by the protocol of the Ecuadorian Ministry of Health, in proportion to the grade of severity. Finally, we identified a low incidence of adverse reactions with antivenom administration, as well as a frequent use of antibiotics.

CONCLUSIONS

The profile of snakebite accidents in the Napo Province is very similar to that described for other localities in the Amazon region of Ecuador and neighboring countries, with its challenges and limitations. Such aspects underlie the importance of establishing a robust and science-based public health program to respond to this frequent, but neglected, tropical disease.

Inspiration from cruzioseptin-1: membranolytic analogue with improved antibacterial properties

Peptide engineering has gained attraction as a source of new cationicity-enhanced analogues with high potential for the design of next-generation antibiotics. In this context, cruzioseptin-1 (CZS-1), a peptide identified from Cruziohyla calcarifer, is recognized for its antimicrobial potency. However, this amidated-peptide is moderately hemolytic. In order to reduce toxicity and increase antimicrobial potency, 3 peptide analogues based on cruzioseptin-1 were designed and evaluated. [K4K15]CZS-1, an analogue with increased cationicity and reduced hydrophobicity, showed antibacterial, antifungal and antiproliferative properties. In addition, [K4K15]CZS-1 is less hemolytic than CZS-1. The in silico and scanning electron microscopy analysis reveal that [K4K15]CZS-1 induces a membranolytic effect on bacteria. Overall, these results confirm the potential of CZS-1 as source of inspiration for design new selective antimicrobial analogues useful for development of new therapeutic agents.

First Insights into the Venom Composition of Two Ecuadorian Coral Snakes

Micrurus is a medically relevant genus of venomous snakes composed of 85 species. Bites caused by coral snakes are rare, but they are usually associated with very severe and life-threatening clinical manifestations. Ecuador is a highly biodiverse country with a complex natural environment, which is home to approximately 20% of identified Micrurus species. Additionally, it is on the list of Latin American countries with the highest number of snakebites. However, there is no local antivenom available against the Ecuadorian snake venoms, and the biochemistry of these venoms has been poorly explored. Only a limited number of samples collected in the country from the Viperidae family were recently characterised. Therefore, this study addressed the compositional patterns of two coral snake venoms from Ecuador, M. helleri and M. mipartitus, using venomics strategies, integrating sample fractionation, gel electrophoresis, and mass spectrometry. Chromatographic and electrophoretic profiles of these snake venoms revealed interspecific variability, which was ascertained by mass spectrometry. The two venoms followed the recently recognised dichotomic toxin expression trends displayed by Micrurus species: M. helleri venom contains a high proportion (72%) of phospholipase A₂, whereas M. mipartitus venom is dominated by three-finger toxins (63%). A few additional protein families were also detected in these venoms. Overall, these results provide the first comprehensive views on the composition of two Ecuadorian coral snake venoms and expand the knowledge of Micrurus venom phenotypes. These findings open novel perspectives to further research the functional aspects of these biological cocktails of PLA₂s and 3FTxs and stress the need for the preclinical evaluation of the currently used antivenoms for therapeutic purposes in Ecuador.

A First Look at the Inhibitory Potential of Urospatha sagittifolia (Araceae) Ethanolic Extract for Bothrops atrox Snakebite Envenomation

Bothrops atrox snakebites are a relevant problem in the Amazon basin. In this biodiverse region, the ethnomedicinal approach plays an important role as an alternative to antivenom therapy. Urospatha sagittifolia (Araceae) is a plant used for this purpose; however, its neutralizing properties have not been scientifically accessed. To fill this gap, we investigated the ability of U. sagittifolia to modulate the catalytic activity of Bothrops atrox venom, and their toxic consequences, such as local damage and lethality. The venom profile of B. atrox was assessed by chromatography and electrophoresis. Inhibition of the three main enzymatic and medically important toxins from the venom was evaluated using synthetic substrates and quantified by chromogenic activity assays. Additionally, the neutralization of lethality, hemorrhage and edema were investigated by in vivo assays. The possible interactions between venom proteins and plant molecules were visualized by polyacrylamide gel electrophoresis. Finally, the phytochemical constituents present in the ethanolic extract were determined by qualitative and quantitative analyses. The ethanolic extract reduced the activity of the three main enzymes of venom target, achieving ranges from 19% to 81% of inhibition. Our in vivo venom neuralizations assays showed a significant inhibition of edema (38.72%) and hemorrhage (42.90%). Additionally, lethality was remarkably counteracted. The highest extract ratio evaluated had a 75% survival rate. Our data support the biomedical value of U. sagittifolia as a source of natural enzyme inhibitors able to neutralize catalytically active B. atrox venom toxins and their toxic effects.

Dissection of phospholipases A2 reveals multifaceted peptides targeting cancer cells, Leishmania and bacteria

Cationic peptides bio-inspired by natural toxins have been recognized as an efficient strategy for the treatment of different health problems. Due to the specific interaction with substrates from biological membranes, snake venom phospholipases (PLA2s) represent valuable scaffolds for the research and development of short peptides targeting parasites, bacteria, and cancer cells. Considering this, we evaluated the in vitro therapeutic potential of three biomimetic peptides (pCergo, pBmTxJ and pBmje) based on three different amino acid sequences from Asp49 PLA2s. First, short amino acid sequences (12-17 in length) derived from these membranolytic toxins were selected using a combination of bioinformatics tools, including AntiCP, AMPA, PepDraw, ToxinPred, and HemoPI. The peptide, from each polypeptide sequence, with the greatest average antimicrobial index, no toxicity, and no hemolysis predicted was synthesized, purified, and characterized. According to in vitro assays performed, pBmje showed moderate cytotoxicity specifically against MCF-7 (breast cancer cells) with an EC50 of 464.85 µM, whereas pBmTxJ showed an antimicrobial effect against Staphylococcus aureus (ATCC 25923) with an MIC of 37.5 µM, and pCergo against E. coli (ATCC 25922) with an MIC of 75 µM. In addition, pCergo showed antileishmanial activity with an EC50 of 93.69 µM and 110.40 µM against promastigotes of Leishmania braziliensis and L. amazonensis, respectively. Altogether, these results confirmed the versatility of PLA2-derived synthetic peptides, highlighting the relevance of the use of these membrane-interacting toxins as specific archetypes for drug design focused on public health problems.

Cruzioseptins, antibacterial peptides from Cruziohyla calcarifer skin, as promising leishmanicidal agents

Screenings of natural products have significantly contributed to the discovery of novel leishmanicidal agents. In this study, three known cruzioseptins-antibacterial peptides from Cruziohyla calcarifer skin-were synthesized and evaluated against promastigotes and amastigotes stages of Leishmania (L.) amazonensis and L. (V.) braziliensis. EC50 ranged from 9.17 to 74.82 μM, being cruzioseptin-1 the most active and selective compound, with selectivity index > 10 for both promastigotes and amastigotes of L. (V.) braziliensis. In vitro infections incubated with cruzioseptins at 50 μM showed up to ∼86% reduction in the amastigote number. Cruzioseptins were able to destabilize the parasite's cell membrane, allowing the incorporation of a DNA-fluorescent dye. Our data also demonstrated that hydrophobicity and charge appear to be advantageous features for enhancing parasiticidal activity. Antimicrobial cruzioseptins are suitable candidates and alternative molecules that deserve further in vivo investigation focusing on the development of novel antileishmanial therapies.

Polyhydroxyalkanoates production from fermented domestic wastewater using phototrophic mixed cultures

Phototrophic mixed cultures (PMC) have been found to be a promising technology to produce polyhydroxyalkanoates (PHA), however, work performed thus far has focussed mainly on the use of synthetic feedstocks and operational conditions that differ from those expectable in full-scale processes. The goals of this work were to study, for the first time, the capability of PMCs to produce PHA using real fermented domestic wastewater as feedstock under mixing/light/temperature conditions that are naturally found in outdoor open systems. Various operational strategies were evaluated in this study to increase PHA productivity, namely the poly(3-hydroxybutyric-co-3-hydroxyvaleric) copolymer (PHBV) by PMC systems. Two lab-scale photobioreactors were operated in parallel, with transient illumination (12 h light/12 h dark) and subjected to feedstock fluctuations under two culture selection strategies that best suit the oxidative conditions of high rate algal ponds (HRAPs) which are commonly applied in wastewater treatment plants (WWTP). Under a permanent carbon feast regime (selection strategy 1), the PMC became highly enriched in phototrophic purple bacteria (PPB), and two complementary conditions that can improve the selection of PHA accumulating bacteria were discovered: phosphate cycling, where 20% PHA/VSS (86HB:14HV in a C-mol basis) with a light phase productivity of 0.23 g PHA/L•d_light phase was attained; and transitioning from selection under low organic loading rate (OLR) to high OLR where 17.6% PHA/VSS (60HB:40HV in C base) with a light phase productivity of 0.18 g PHA/L•d_light phase was achieved. Under a feast and famine regime (selection strategy 2), a PMC consortium of microalgae and PPB was obtained, and a multiple pulse feeding strategy during the first hours of the light phase in the selector reactor led to a 26.1% PHA/VSS (36HB:64HV in C base) content, with a productivity of 0.26 g PHA/L•d_light phase and 0.52 g PHA/L•d_feast phase. An accumulation test under higher light intensity led to 30.8% PHA/VSS (85HB:15HV on a C-mol basis) with a productivity of 2.67 g PHA/L•d, along the 8 h of accumulation.

Peptides to Tackle Leishmaniasis: Current Status and Future Directions

Peptide-based drugs are an attractive class of therapeutic agents, recently recognized by the pharmaceutical industry. These molecules are currently being used in the development of innovative therapies for diverse health conditions, including tropical diseases such as leishmaniasis. Despite its socioeconomic influence on public health, leishmaniasis remains long-neglected and categorized as a poverty-related disease, with limited treatment options. Peptides with antileishmanial effects encountered to date are a structurally heterogeneous group, which can be found in different natural sources—amphibians, reptiles, insects, bacteria, marine organisms, mammals, plants, and others—or inspired by natural toxins or proteins. This review details the biochemical and structural characteristics of over one hundred peptides and their potential use as molecular frameworks for the design of antileishmanial drug leads. Additionally, we detail the main chemical modifications or substitutions of amino acid residues carried out in the peptide sequence, and their implications in the development of antileishmanial candidates for clinical trials. Our bibliographic research highlights that the action of leishmanicidal peptides has been evaluated mainly using in vitro assays, with a special emphasis on the promastigote stage. In light of these findings, and considering the advances in the successful application of peptides in leishmaniasis chemotherapy, possible approaches and future directions are discussed here.

Bothrops atrox from Ecuadorian Amazon: Initial analyses of venoms from individuals

Bothrops atrox is the most clinically relevant snake species within the Amazon region, which includes Ecuadorian territories. It comprises a large distribution, which could contribute to the genetic and venomic variation identified in the species. The high variability and protein isoform diversity of its venom are of medical interest, since it can influence the clinical manifestations caused by envenomation and its treatment. However, in Ecuador there is insufficient information on the diversity of venomic phenotypes, even of relevant species such as B. atrox. Here, we characterized the biochemical and toxicological profiles of the venom of six B. atrox individuals from the Ecuadorian Amazon. Differences in catalytic activities of toxins, elution profiles in liquid chromatography, electrophoretic patterns, and toxic effects among the analyzed samples were identified. Nonetheless, in the preclinical testing of antivenom, two samples from Mera (Pastaza) required a higher dose to achieve total neutralization of lethality and hemorrhage. Taken together, these data highlight the importance of analyzing individual venoms in studies focused on the outcomes of envenoming.

Correlation between amyloid deposits affecting renal compartments and glomerular filtration rate during renal biopsy in a renal amyloidosis case series

Amyloidosis comprises a group of disorders that accumulate modified autologous proteins in organs, mainly the kidneys. Few studies have addressed the amyloid compartmental distribution and associated clinical outcomes. The aim of this study was to present a case series of renal amyloidosis correlating histopathological data with glomerular filtration rate (GFR) during kidney biopsy. We studied 53 cases reviewed by nephropathologists from 2000 to 2018 in a single kidney biopsy center in Brazil. GFR was estimated using the CKD-EPI formula. Cases were divided into Group A ≥60 and Group B <60 mL·min⁻¹·(1.73 m²)⁻¹ using the estimated GFR during kidney biopsy. Semiquantitative histopathological study was performed, including extension and distribution of amyloid deposits by compartments (glomeruli, tubulointerstitial tissue, and vessels). Statistical analyses were made to understand associations with lower GFR. No difference was seen for age, gender, proteinuria, hematuria, subtype of amyloid protein, arteriosclerosis, interstitial fibrosis/infiltrate, or glomerular and interstitial amyloid deposits. After a previous P value <0.1 in the descriptive analysis, the following variables were selected: globally sclerotic glomeruli, high blood pressure, and the extension of vascular amyloid deposition. A binary logistic regression model with GFR as the dependent variable showed history of hypertension and vascular amyloid to be robust and independent predictors of Group B <60 mL·min⁻¹·(1.73 m²)⁻¹. Beyond the histopathologic diagnosis of amyloidosis, a semiquantitative approach on renal biopsy could provide new insights. Vascular amyloid is an independent predictor of renal dysfunction in cases of renal amyloidosis.

Assessing the stability of historical and desiccated snake venoms from a medically important Ecuadorian collection

Bothrops asper and Bothrops atrox are important venomous snakes from Ecuador responsible for the most of ophidic accidents, which in the past were treated with a national polyvant antivenom. For years, the venom pools were collected and stored at room temperature in a laboratory. Taking into account the controversial ability of desiccated samples to retain their biological effects and enzymatic activities, we investigated the biochemical and toxicological properties of venoms after years of storage. The proteomic profiles of historical venoms analyzed by high-performance liquid chromatography and electrophoresis are very similar. The fresh batches of venom were more lethal than those stored for years, just as the initial and current LD₅₀ values of these samples changed. Significant differences were showed in the myotoxic and hemorrhagic activity of some venom pools, while no significant statistical differences were found for the edema activity. The enzymatic assays revealed a variation in proteolytic activity on azocasein and phospholipase A₂ activity, and low differences were reported for thrombin-like serine protease activity. The maintenance of the proteomic profile and certain toxicological activities convert this venom library in a valuable source for research purposes. Nonetheless, the significative reduction of toxicological activities, such as hemorrhagic activity not feasible using these samples for the antivenom production.

Potential use of 13-mer peptides based on phospholipase and oligoarginine as leishmanicidal agents

Phospholipase A₂ toxins present in snake venoms interact with biological membranes and serve as structural models for the design of small peptides with anticancer, antibacterial and antiparasitic properties. Oligoarginine peptides are capable of increasing cell membrane permeability (cell penetrating peptides), and for this reason are interesting delivery systems for compounds of pharmacological interest. Inspired by these two families of bioactive molecules, we have synthesized two 13-mer peptides as potential antileishmanial leads gaining insights into structural features useful for the future design of more potent peptides. The peptides included p-Acl, reproducing a natural segment of a Lys49 PLA₂ from Agkistrodon contortrix laticinctus snake venom, and its p-AclR7 analogue where all seven lysine residues were replaced by arginines. Both peptides were active against promastigote and amastigote forms of Leishmania (L.) amazonensis and L. (L.) infantum, while displaying low cytotoxicity for primary murine macrophages. Spectrofluorimetric studies suggest that permeabilization of the parasite's cell membrane is the probable mechanism of action of these biomolecules. Relevantly, the engineered peptide p-AclR7 was more active in both life stages of Leishmania and induced higher rates of ethidium bromide incorporation than its native template p-Acl. Taken together, the results suggest that short peptides based on phospholipase toxins are potential scaffolds for development of antileishmanial candidates. Moreover, specific amino acid substitutions, such those herein employed, may enhance the antiparasitic action of these cationic peptides, encouraging their future biomedical applications.

Potential of synthetic chalcone derivatives to prevent marine biofouling

Biofouling represents a major economic, environmental and health concern for which new eco-friendly solutions are needed. International legislation has restricted the use of biocidal-based antifouling coatings, and increasing efforts have been applied in the search for environmentally friendly antifouling agents. This research work deals with the assessment of the interest of a series of synthetic chalcone derivatives for antifouling applications. Sixteen chalcone derivatives were synthesized with moderate yields (38-85%). Antifouling bioactivity of these compounds was assessed at different levels of biological organization using both anti-macrofouling and anti-microfouling bioassays, namely an anti-settlement assay using mussel (Mytilus galloprovincialis) larvae, as well as marine bacteria and microalgal biofilms growth inhibition bioassays. Results showed that three compounds (11, 12, and 16) were particularly active against the settlement of mussel larvae (EC₅₀ 7.24-34.63 μM), being compounds 12 and 16 also able to inhibit the growth of microfouling species (EC₅₀ 4.09-20.31 μM). Moreover, the most potent compounds 12 and 16 were found to be non-toxic to the non-target species Artemia salina (<10% mortality at 25 μM). A quantitative structure-activity relationship model predicted that descriptors describing the ability of molecules to form hydrogen bonds and encoding the shape, branching ratio and constitutional diversity of the molecule were implied in the antifouling activity against the settlement of mussel larvae. This work elucidates for the first time the relevance of synthesizing chalcone derivatives to generate new non-toxic products to prevent marine biofouling.

Harnessing snake venom phospholipases A2 to novel approaches for overcoming antibiotic resistance

The emergence of antibiotic resistance drives an essential race against time to reveal new molecular structures capable of addressing this alarming global health problem. Snake venoms are natural catalogs of multifunctional toxins and privileged frameworks, which serve as potential templates for the inspiration of novel treatment strategies for combating antibiotic resistant bacteria. Phospholipases A₂ (PLA₂ s) are one of the main classes of antibacterial biomolecules, with recognized therapeutic value, found in these valuable secretions. Recently, a number of biomimetic oligopeptides based on small fragments of primary structure from PLA₂ toxins has emerged as a meaningful opportunity to overcome multidrug-resistant clinical isolates. Thus, this review will highlight the biochemical and structural properties of antibacterial PLA₂ s and peptides thereof, as well as their possible molecular mechanisms of action and key roles in development of effective therapeutic strategies. Chemical strategies possibly useful to convert antibacterial peptides from PLA₂ s to efficient drugs will be equally addressed.

In vitro effects of Crotalus atrox snake venom on chick and mouse neuromuscular preparations

The neuromuscular effect of venoms is not a major clinical manifestation shared between rattlesnakes native to the Americas, which showed two different venom phenotypes. Taking into account this dichotomy, nerve muscle preparations from mice and chicks were used to investigate the ability of Crotalus atrox venom to induce in vitro neurotoxicity and myotoxicity. Unlike crotalic venoms of South America, low concentrations of C. atrox venom did not result in significant effects on mouse neuromuscular preparations. The venom was more active on avian nerve-muscle, showing reduction of twitch heights after 120 min of incubation with 10, 30 and 100 μg/mL of venom with diminished responses to agonists and KCl. Histological analysis highlighted that C. atrox was myotoxic in both species of experimental animals; as evidenced by degenerative events, including edematous cells, delta lesions, hypercontracted fibers and muscle necrosis, which can lead to neurotoxic action. These results provide key insights into the myotoxicity and low neurotoxicity of C. atrox in two animal models, corroborating with previous genomic and proteomic findings and would be useful for a deeper understanding of venom evolution in snakes belonging to the genus Crotalus.

Renal safety after one year of sofosbuvir-based therapy for chronic hepatitis C: A Brazilian "real-life" study

WHAT IS KNOWN AND OBJECTIVE

Sofosbuvir(SOF)-based regimens have been administrated with excellent efficacy in chronic hepatitis C. Few uncontrolled ("real-life") studies consider the assessment of renal function when evaluating their post-treatment outcomes. This study aims to evaluate renal biomarkers in a "real-life" experience with chronic hepatitis C patients treated with SOF therapy in a long-term follow-up.

METHODS

Serum and urinary biomarkers were analysed before, at the end of therapy (EoT), after 12 weeks (sustained virological response-SVR) and one year (1y) post-treatment. Patients were categorized according to baseline glomerular filtration rate (GFR-cut-off 45 mL/min/1.73 m² ).

RESULTS

Ninety-four patients with a mean age of 59.9 ± 8.5 years were included; 98.9% of patients reached SVR. Significant improvement in renal biomarkers was observed in patients with GFR ≥45 mL/min/1.73 m² , as indicated by a progressive increase in mean GFR values until 1y. No evidence of tubular dysfunction was identified. Patients with baseline GFR <45 mL/min/1.73 m² did not experience alterations in renal biomarkers; however, a mean change of +10.7 in GFR values was observed. We noticed significant upper stage transition in the CKD classification, and 58.7% of patients achieved G1 stage at 1y (P < .0001).

WHAT IS NEW AND CONCLUSION

In a "real-life experience" of a Brazilian centre, SOF therapy appears to guarantee renal safety for patients with chronic hepatitis C followed until one year after treatment.

Identification of a novel UMOD mutation (c.163G>A) in a Brazilian family with autosomal dominant tubulointerstitial kidney disease

Autosomal dominant tubulointerstitial kidney disease (ADTKD) is characterized by autosomal dominant inheritance, progressive chronic kidney disease, and a bland urinary sediment. ADTKD is most commonly caused by mutations in the UMOD gene encoding uromodulin (ADTKD-UMOD). We herein report the first confirmed case of a multi-generational Brazilian family with ADTKD-UMOD, caused by a novel heterozygous mutation (c.163G>A, GGC→AGC, p.Gly55Ser) in the UMOD gene. Of 41 family members, 22 underwent genetic analysis, with 11 individuals found to have this mutation. Three affected individuals underwent hemodialysis, one peritoneal dialysis, and one patient received a kidney transplant from a family member later found to be genetically affected. Several younger individuals affected with the mutation were also identified. Clinical characteristics included a bland urinary sediment in all tested individuals and a kidney biopsy in one individual showing tubulointerstitial fibrosis. Unlike most other reported families with ADTKD-UMOD, neither gout nor hyperuricemia was found in affected individuals. In summary, we report a novel UMOD mutation in a Brazilian family with 11 affected members, and we discuss the importance of performing genetic testing in families with inherited kidney disease of unknown cause.

Synthesis, characterization and photocatalytic properties of nanostructured CoFe2O4 recycled from spent Li-ion batteries

In this study, cobalt (Co) was recycled from spent lithium ion batteries (LIBs) and used to synthesize cobalt ferrite (CoFe₂O₄-LIBs), which was applied as a catalyst for heterogeneous photo Fenton reactions that discolored methylene blue (MB) dye. The co-precipitation method was used to synthesize CoFe₂O₄-LIBs and CoFe₂O₄-R nanoparticles with spinel structures using as raw materials of the LIB cathodes and commercial reagents. X-ray diffraction (XRD) identified the formation of spinel-type CoFe₂O₄, which formed clusters that could be seen under scanning electron microscopy (SEM) analysis and nanometric particles seen under transmission electron microscopy (TEM). Inductively Coupled Plasma Optical Emission Spectrometer (ICP OES) analysis was used to determine the concentrations of metals present in the ferrite, which reached 6.5% (w/w) of Co. The optimal conditions for discoloring the dye were evaluated using a factorial design. Using CoFe₂O₄ as a catalyst, the best conditions for catalytic reaction were pH 3, 30.0 mg of catalyst, and 8.0 mL of H₂O₂ 73% (v/v). Discoloration efficiencies of 87.3% and 87.7% were obtained from CoFe₂O₄-R and CoFe₂O₄-LIBs, respectively. Therefore, CoFe₂O₄-LIBs proved to be an efficient catalyst for discoloring MB dye using heterogeneous photo-Fenton reactions. This work is of scientific, social, economic, and environmental interest. It investigates the process of synthesizing,characterizing CoFe₂O₄LIBs and the efficiency of degrading MB dye, subjects that have economic and environmental, and therefore, social interest. The work has scientific interest particularly because of the correlation between the structure of the recycled material and its catalytic properties.

Pilot Study of Early Monitoring Using Urinary Screening for BK Polyomavirus as a Strategy for Prevention of BKV Nephropathy in Kidney Transplantation

BACKGROUND

Urine monitoring programs represent an important strategy for early diagnosis of reactivation of BK polyomavirus (BKV) in kidney transplant recipients. This study analyzes a BKV urine screening model in kidney transplant patients.

METHODS

Urinary screening for BKV reactivation was performed by urinary decoy cell and polymerase chain reaction (PCR) tests in samples from 32 consecutive kidney transplant patients, collected in a 6-month follow-up period. PCR in plasma samples and BKV immunohistochemical studies to assess BKV renal disease, if a kidney biopsy was indicated, were performed.

RESULTS

The urinary screening for BKV among 32 renal receptors was positive in 18 patients (56%) by the concomitant use of the decoy cells and/or qualitative PCR at some time during the study period. Transfusion before transplantation was significantly associated with urinary decoy cell positive screening (odds ratio = 11; 95% confidence interval = 1.47 to 82.4; P < .05); and so was male sex (odds ratio = 2.02; 95% confidence interval = 1.07 to 3.83; P < .05). The clinical management of screening positive cases consisted of decreasing or changing the immunosuppression regimen. Sixteen renal biopsies were performed. Immunohistochemistry for SV40 T antigen was negative in all biopsies. After 1 year of follow-up, no patient developed BKV-associated nephropathy, and there was no difference in renal function between patients positive and negative for BKV urinary screening.

CONCLUSIONS

Early urinary monitoring is effective in detection of BKV replication and represents a good strategy to minimize the deleterious effects caused by the presence of the virus on preservation of graft function.

Silica Coating of Nonsilicate Nanoparticles for Resin-Based Composite Materials

This study was designed to develop and characterize a silica-coating method for crystalline nonsilicate ceramic nanoparticles (Al₂O₃, TiO₂, and ZrO₂). The hypothesis was that the coated nonsilicate nanoparticles would stably reinforce a polymeric matrix due to effective silanation. Silica coating was applied via a sol-gel method, with tetraethyl orthosilicate as a silica precursor, followed by heat treatment. The chemical and microstructural characteristics of the nanopowders were evaluated before and after silica coating through x-ray diffraction, BET (Brunauer-Emmett-Teller), energy-dispersive x-ray spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy analyses. Coated and noncoated nanoparticles were silanated before preparation of hybrid composites, which contained glass microparticles in addition to the nanoparticles. The composites were mechanically tested in 4-point bending mode after aging (10,000 thermal cycles). Results of all chemical and microstructural analyses confirmed the successful obtaining of silica-coated nanoparticles. Two distinct aspects were observed depending on the type of nanoparticle tested: 1) formation of a silica shell on the surface of the particles and 2) nanoparticle clusters embedded into a silica matrix. The aged hybrid composites formulated with the coated nanoparticles showed improved flexural strength (10% to 30% higher) and work of fracture (35% to 40% higher) as compared with composites formulated with noncoated nanoparticles. The tested hypothesis was confirmed: silanated silica-coated nonsilicate nanoparticles yielded stable reinforcement of dimethacrylate polymeric matrix due to effective silanation. The silica-coating method presented here is a versatile and promising novel strategy for the use of crystalline nonsilicate ceramics as a reinforcing phase of polymeric composite biomaterials.

De novo posttransplantation nonlymphoproliferative malignancies in liver transplant recipients

The risk of developing de novo malignancies after liver transplantation is around 1% per year. The incidence varies from 3% to 15%; it is greater than that in the general population. The potential causes for cancer after solid organ grafting are: chronic immunosuppression and human herpes viral infection. The objective of this paper was to review the medical literature about the subject to verify the incidence of de novo malignancies in our service. We performed retrospective analysis of the medical files of 325 successive patients undergoing orthotopic liver transplantation from September 1991 to December 2006. We analyzed the type of tumor, the risk factors, the treatment modality, and the patient survivals. Recurrences of hepatocellular carcinoma were excluded. There were 5 (1.54%) men of average age 50.2 years, and an 80% mortality rate. Their survival time was affected by the nature of the tumor and by the late manifestations of intestinal obstruction allowing adequate surgical treatment. Four of the patients displayed heavy alcohol and tobacco consumption before transplantation. Screening for premalignant lesions must be strongly encouraged to achieve better postoperative results.

Is hepatitis C a risk factor to posttransplant diabetes mellitus after renal transplantation in patients using tacrolimus?

The objective of this study was to evaluate the association between previous hepatitis C virus (HCV) infection and the occurrence of posttransplant diabetes mellitus (PTDM) among patients undergoing kidney transplants using tacrolimus (FK). From August 1999 to January 2003, 66 patients (36.4 +/- 15.5 years) underwent kidney transplantation using an immunosuppressive regimen of tacrolimus, mycophenolate mofetil, or azathioprine and steroids. Thirty-four patients (52%) received kidneys from living donors and 32 (48%) from cadaveric donors. The diagnosis of diabetes mellitus was established after two consecutive ambulatory measurements of fasting glycemia > or = 126 mg/dL. Thirty-five percent of the patients (23/66) were HCV+ and 65% (43/66) HCV-. Of the 66 patients, 33% (22) developed PTDM, 19 (82%) from the HCV+ group and only 3 (7%) from the HCV- group. Among those who developed PDTM, the diagnosis was established in the first 2 posttransplant months in most cases (68.2%). The results showed a significant association between HCV and PTDM (P < or = .0001). In this group of patients HCV infection was strongly associated with the development of PTDM. Therefore, additional care is required regarding the immunosuppressive regimen among patients with chronic HCV infection.

Efficacy and tolerability of pantoprazole versus ranitidine in the treatment of reflux esophagitis and the influence of Helicobacter pylori infection on healing rate

Patients with reflux esophagitis (grade II or III, Savary-Miller, intention-to-treat, n=256, age range 19-82 years) were randomly assigned to a double-blind, double-dummy treatment with either pantoprazole 40 mg once daily or ranitidine 150 mg twice daily. After 4 weeks, each patient was clinically and endoscopically assessed. Failure to heal required a further 4 weeks of treatment and a new evaluation thereafter. After 4 weeks, healing of lesions was confirmed in 63% (69 out of 109) of patients receiving pantoprazole and in 22% (25 out of 113) receiving ranitidine (P < 0.001, per protocol population). After 8 weeks, the cumulative healing rates were 88% and 46%, respectively (P < 0.001). Complete freedom from esophagitis-related symptoms (acid eructation, heartburn, pain while swallowing) was greater in the pantoprazole than in ranitidine group after 2 and 4 weeks (74% vs. 47%; 87% vs. 52%, respectively, P < 0.001). After 4 weeks, the healing rate was 76% in Helicobacter pylori (Hp)-positive vs. 45% in Hp-negative patients treated with pantoprazole (P < 0.01). The Hp status did not influence healing rates in patients treated with ranitidine. The most frequent adverse events in the pantoprazole group were diarrhea and somnolence (2-3% of patients), and in the ranitidine group, headache, diarrhea, dizziness, increase of liver enzymes and pruritus (2-4% of patients). In conclusion, pantoprazole was more effective than ranitidine in the healing rate and relief from reflux esophagitis-associated symptoms, and Hp infection was associated with higher healing rate during therapy with pantoprazole but not with ranitidine.

[Trophic niches in calyptrate Diptera in Rio de Janeiro, RJ]

Niche breadth and niche overlap of flies were estimated. The flies were breeding in different environments in Rio de Janerio (rural, urban and forest). It were used as a larvae substrate: banana mashed, mouse carcass, fish (sardine), bovine liver, shrimp and fresh human faeces. It were bred 14,294 flies, belonging to four families: Calliphoridae, Fanniidae, Muscidae and Sarcophagidae. The greater niche overlap values observed were: rural area: Phaenicia cuprina versus Chrysomya megacephala; urban area: Phaenicia eximia versus Sarcodexia innota and P. eximia versus Synthesiomyia nudiseta; forest area: P. eximia versus Hemilucilia flavifacies. The greater niche breadth recorded were: rural area: Peckia chrysostoma; urban area: S. nudiseta and Musca domestica; forest area: Euboettcheria collusor and P. eximia.

Immunocytochemistry of mucosal changes in patients infected with the intestinal nematode Strongyloides stercoralis

AIM

To investigate the immunopathological changes in duodenal tissues induced by strongyloidiasis and to relate these to degrees of clinical severity.

METHODS

Tissues taken from 21 patients showing mild, moderate or severe symptoms of strongyloidiasis, and from non-infected controls, were sectioned and stained immunocytochemically for IgA, secretory component (SC) and HLA-DR. Immunopathology was assessed by changes in numbers, intensity and distribution of stained cells.

RESULTS

Parasitised individuals showed villous atrophy and crypt hyperplasia. There was notable infiltration of the lamina propria by IgA positive plasma cells and of the epithelium by intraepithelial lymphocytes. Infection was also associated with increased expression of SC and decreased expression of HLA-DR in epithelial cells. Changes in all parameters correlated with degree of clinical severity.

CONCLUSIONS

Profound mucosal changes are induced by strongyloidiasis. Some are analogous to those seen in coeliac disease, but others seem quite unusual. It is likely that these changes are functionally related to the immunopathophysiological consequences of infection seen in patients with severe disease.

Immunocytochemical demonstration that human duodenal Brunner's glands may participate in intestinal defence

The immunocytochemical demonstration of IgA and IgM in some secretory units of human Brunner's glands, associated with the presence of secretory component in all secretory cells, indicates the possibility that these glands assist the function of the intestinal crypts in transporting immunoglobulins into the gut lumen. In addition, the presence of muramidase (lysozyme) in the cells of the secretory units suggests that Brunner's glands continuously secrete bactericidal enzyme, thus reinforcing the function of the Paneth cells as contributors to nonspecific defence (innate immunity) in the intestinal tract.