Tumor mutational burden predictability in head and neck squamous cell carcinoma patients treated with immunotherapy: systematic review and meta-analysis.

BACKGROUND: Tumor mutational burden (TMB) has been demonstrated to predict the response to immune checkpoint inhibitors (ICIs) in various cancers. However, the role of TMB in head and neck squamous cell carcinoma (HNSCC) has not yet been specifically addressed. Since HNSCC patients exhibit a rather limited response to ICIs, there is an unmet need to develop predictive biomarkers to improve patient selection criteria and the clinical benefit of ICI treatment. METHODS: We conducted a systematic review and meta-analysis according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. HNSCC cohort studies were selected when TMB prior to ICI treatment was evaluated, TMB cutoff value was available, and the prognostic value of TMB was evaluated by time-to-event survival analysis. A total of 11 out of 1960 articles were analyzed, including 1200 HNSCC patients. RESULTS: The results showed that those patients harboring high TMB exhibited a significantly superior overall response rate (OR = 2.62; 95% CI 1.74-3.94; p < 0.0001) and a survival advantage (HR = 0.53; 95% CI 0.39-0.71; p < 0.0001) after ICI treatment. CONCLUSION: This is the first meta-analysis to demonstrate a higher response and clinical benefit from ICI therapy in HNSCC patients with high TMB.

Chloroplast envelope K+/H+ antiporters are involved in cytosol pH regulation.

Variations in light intensity induce cytosol pH changes in photosynthetic tissues, providing a possible signal to adjust a variety of biochemical, physiological and developmental processes to the energy status of the cells. It was shown that these pH changes are partially due to the transport of protons in or out of the thylakoid lumen. However, the ion transporters in the chloroplast that transmit these pH changes to the cytosol are not known. KEA1 and KEA2 are K+/H+ antiporters in the chloroplast inner envelope that adjust stromal pH in light-to-dark transitions. We previously determined that stromal pH is higher in kea1kea2 mutant cells. In this study, we now show that KEA1 and KEA2 are required to attenuate cytosol pH variations upon sudden light intensity changes in leaf mesophyll cells, showing they are important components of the light-modulated pH signalling module. The kea1kea2 mutant mesophyll cells also have a considerably less negative membrane potential. Membrane potential is dependent on the activity of the plasma membrane proton ATPase and is regulated by secondary ion transporters, mainly potassium channels in the plasma membrane. We did not find significant differences in the activity of the plasma membrane proton pump but found a strongly increased membrane permeability to protons, especially potassium, of the double mutant plasma membranes. Our results indicate that chloroplast envelope K+/H+ antiporters not only affect chloroplast pH but also have a strong impact on cellular ion homeostasis and energization of the plasma membrane.

Combined PIK3CA and SOX2 Gene Amplification Predicts Laryngeal Cancer Risk beyond Histopathological Grading.

The PIK3CA and SOX2 genes map at 3q26, a chromosomal region frequently amplified in head and neck cancers, which is associated with poor prognosis. This study explores the clinical significance of PIK3CA and SOX2 gene amplification in early tumorigenesis. Gene copy number was analyzed by real-time PCR in 62 laryngeal precancerous lesions and correlated with histopathological grading and laryngeal cancer risk. Amplification of the SOX2 and PIK3CA genes was frequently detected in 19 (31%) and 32 (52%) laryngeal dysplasias, respectively, and co-amplification in 18 (29%) cases. The PIK3CA and SOX2 amplifications were predominant in high-grade dysplasias and significantly associated with laryngeal cancer risk beyond histological criteria. Multivariable Cox analysis further revealed PIK3CA gene amplification as an independent predictor of laryngeal cancer development. Interestingly, combined PIK3CA and SOX2 amplification allowed us to distinguish three cancer risk subgroups, and PIK3CA and SOX2 co-amplification was found the strongest predictor by ROC analysis. Our data demonstrate the clinical relevance of PIK3CA and SOX2 amplification in early laryngeal tumorigenesis. Remarkably, PIK3CA amplification was found to be an independent cancer predictor. Furthermore, combined PIK3CA and SOX2 amplification is emerging as a valuable and easy-to-implement tool for cancer risk assessment in patients with laryngeal precancerous lesions beyond current WHO histological grading.

An Exploration of Sex Trading for Compensation and LGBTQ+ Inclusive Screening Practices: Perspectives of Young People who have Experienced Sex Trading and/or Homelessness.

Young people's perspectives on social and healthcare providers' assessments of sex trading for financial compensation are lacking. This is particularly important for LGBTQ+ youth who experience substantial barriers in navigating health and social services. Further, increased internet access (because of COVID-19 and other factors) has changed the landscape of the sex trades in ways that are not fully understood. Our study aimed to understand (1) how young people trade sex, and (2) provider strategies that increase youths' comfort in disclosing sex trading and related risks. This community-based participatory research study surveyed currently or formerly homeless youth (ages 16-29). We co-created a cross sectional survey that explored youths' perceptions of: (1) sex trading type, compensation, and meaning; and (2) practices to increase youths' comfort in disclosing sex trading. Participants (N = 103; Mage = 22.9 [SD = 3.5]; 34% white, 55% ciswomen/21% trans; 51% queer) reported that "sex trading" signified multiple meanings, ranging from sex work/occupation to exploitation/trafficking, and included diverse in-person and virtual forms for varied compensation types. Youth reported being more comfortable disclosing when the provider indicated they would advocate for them if they are victims of discrimination. Compared to cisgender youth, trans youth reported feeling significantly more comfortable disclosing sexual activity when a service provider used gender/sexuality inclusive practices (e.g., pronoun pins). Findings suggest important implications for gender-inclusive practice strategies to ultimately reduce potential harms of sex trading and multi-item measures to assess the complexity of sex trading.

How Do Providers Assess Young People for Risk of Sex Trafficking? Observed Indicators, Follow-Up, and Assessment Questions from a Sample of Social Service Providers.

The extent to which service providers across systems identify and assess potentially sex trafficked youth is understudied. The purpose of this study is to determine whether and how providers observe relevant indicators and assess for sex trafficking risk among minors (ages 12-17), young adults (ages 18-29), and families of minors. A cross-sectional, web-based survey was disseminated to service providers, who represented child welfare, youth justice, and social services (e.g. runaway youth, sexual violence), in a region of a Midwestern state (United States). Participants (N=267) were asked whether they provided direct services to minors (ages 12-17, n=245), adults (ages 18-29, n=148), and/or families/foster families of minors (ages 12-17, n=163), resulting in three respective client groups. Survey items assessed the extent to which providers (1) identified possible sex trafficking indicators across 5 domains; (2) took follow up actions; and (3) asked risk assessment questions. T-tests were conducted to examine differences between those who reported receiving sex trafficking trainings, compared to those who did not. Results suggest that the most commonly identified indicators included depressive symptoms, shame and guilt, lack of social support. Least common indicators included torture, false IDs, hotel involvement. A third of minor-aged providers did not ask sex trafficking risk assessment questions. Providers reported asking fewer clients about online sex trading than in-person forms. There were statistically significant differences among providers who received training. Implications, including provider strategies for assessing online sex trading and organizational protocols to enhance sex trafficking identification, are discussed.

Economic assessment of incorporating the hexavalent vaccine as part of the National Immunization Program of Peru.

BACKGROUND: This study aimed to estimate the economic impact of replacing the current Peruvian primary immunization scheme for infants under 1 year old with an alternative scheme with similar efficacy, based on a hexavalent vaccine. METHODS: A cost-minimization analysis compared the costs associated with vaccine administration, adverse reactions medical treatment, logistical activities, and indirect social costs associated with time spent by parents in both schemes. A budgetary impact analysis assessed the financial impact of the alternative scheme on healthcare budget. RESULTS: Incorporating the hexavalent vaccine would result in a 15.5% net increase in healthcare budget expenditure ($48,281,706 vs $55,744,653). Vaccination costs would increase by 54.1%, whereas logistical and adverse reaction costs would be reduced by 59.8% and 33.1%, respectively. When including indirect social costs in the analysis, the budgetary impact was reduced to 8.7%. Furthermore, the alternative scheme would enable the liberation of 17.5% of national vaccines storage capacity. CONCLUSIONS: Despite of the significant reduction of logistical and adverse reaction costs, including the hexavalent vaccine into the National Immunization Program of Peru in place of the current vaccination scheme for infants under 1 year of age would increase the public financial budget of the government as it would represent larger vaccine acquisition costs. Incorporating the indirect costs would reduce the budgetary impact demonstrating the social value of the alternative scheme. This merits consideration by government bodies, and future studies investigating such benefits would be informative.

Therapeutic Leukapheresis: Experience of a Single Oncologic Centre.

Introduction: Leukostasis refers to clinical symptoms caused by hyperleukocytosis seen in some haematological diseases such as leukaemia. Cytoreduction can be achieved by therapeutic leukapheresis. The aim of this study was to retrospectively analyse the procedures performed in our Centre and to evaluate their efficacy and safety. Methods: This was a retrospective study of all the therapeutic leukapheresis procedures carried out in our Centre between January 1998 and December 2020. The sample collection was obtained through the review of the clinical files of the respective patients. Statistical analysis was performed using the software R v.4.0.1. A total of 54 therapeutic leukapheresis procedures were performed in 31 patients in our Centre. Results: After these procedures clinical improvement was observed in 16 patients and we verify that there was a significant difference in survival between the group that improved and the group that maintained the same clinical condition or worsened. The lack of immediate clinical improvement was a sign of a poor prognosis. Laboratory efficacy occurred in 16 patients who had a reduction in white blood cell count, with a 39.1% reduction after 24 h, and did not succeed in 15 patients, who had no reduction. However, in this case there is no significant difference in survival between the two groups. There was some complication in 53.9% of the procedures, with hypocalcaemia being the most frequent, which was observed in 22 procedures. Only 4 patients experienced serious side effects but these adverse reactions cannot be attributed to the procedures carried out. The overall survival rate 6 months after this treatment was 51.6%. Conclusion: Despite the reduced number of patients, we conclude that therapeutic leukapheresis is a safe and effective option that may still have a therapeutic role in some cases.

Tumor-Intrinsic Nuclear ß-Catenin Associates with an Immune Ignorance Phenotype and a Poorer Prognosis in Head and Neck Squamous Cell Carcinomas.

Activation of WNT/ß-catenin signaling has been associated with a non-T-cell-inflamed tumor microenvironment (TME) in several cancers. The aim of this work was to investigate the relationship between ß-catenin signaling and TME inflammation in head and neck squamous cell carcinomas (HNSCCs). Membrane and nuclear ß-catenin expression, PD-L1 expression, and CD8+ tumor-infiltrating lymphocyte (TIL) density were jointly evaluated by immunohistochemistry in a series of 372 HPV-negative HNSCCs. Membrane ß-catenin levels decreased in carcinomas compared to the normal epithelium. Positive nuclear ß-catenin was detected in 50 tumors (14.3%) and was significantly associated with a low CD8+ TIL density (168 cells/mm2 versus 293 cells/mm2 in nuclear-ß-catenin-negative cases; p = 0.01) and a tendency for a lower expression of PD-L1, resulting in association with a noninflamed TME (i.e., type II, immunological ignorance). Multivariate Cox analysis further demonstrated that low infiltration by CD8+ TILs (HR = 1.6, 95% CI = 1.19-2.14, p = 0.002) and nuclear ß-catenin expression (HR = 1.47, 95% CI = 1.01-2.16, p = 0.04) were both independently associated with a poorer disease-specific survival. In conclusion, tumor-intrinsic nuclear ß-catenin activation is associated with a non-inflamed TME phenotype and a poorer prognosis, thereby suggesting a possible implication as an immune exclusion mechanism for a subset of HNSCC patients.

Psycho-Neuro-Endocrine-Immunology: A Role for Melatonin in This New Paradigm.

Psychoneuroendocrinoimmunology is the area of study of the intimate relationship between immune, physical, emotional, and psychological aspects. This new way of studying the human body and its diseases was initiated in the last century's first decades. However, the molecules that participate in the communication between the immune, endocrine, and neurological systems are still being discovered. This paper aims to describe the development of psychoneuroendocrinoimmunology, its scopes, limitations in actual medicine, and the extent of melatonin within it.

Plastidial transporters KEA1 and KEA2 at the inner envelope membrane adjust stromal pH in the dark.

Photosynthesis and carbon fixation depend critically on the regulation of pH in chloroplast compartments in the daylight and at night. While it is established that an alkaline stroma is required for carbon fixation, it is not known how alkaline stromal pH is formed, maintained or regulated. We tested whether two envelope transporters, AtKEA1 and AtKEA2, directly affected stromal pH in isolated Arabidopsis chloroplasts using the fluorescent probe 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF). External K+ -induced alkalinization of the stroma was observed in chloroplasts from wild-type (WT) plants but not from kea1kea2 mutants, suggesting that KEA1 and KEA2 mediate K+ uptake/H+ loss to modulate stromal pH. While light-stimulated alkalinization of the stroma was independent of KEA1 and KEA2, the rate of decay to neutral pH in the dark is delayed in kea1kea2 mutants. However, the dark-induced loss of a pH gradient across the thylakoid membrane was similar in WT and mutant chloroplasts. This indicates that proton influx from the cytosol mediated by envelope K+ /H+ antiporters contributes to adjustment of stromal pH upon light to dark transitions.

A Systematic Review of Technology-Based Prevention and Treatment Interventions for Perinatal Depression and Anxiety in Latina and African American Women.

INTRODUCTION: Latina and African American women have elevated risk for perinatal depression and anxiety but have low rates of treatment engagement. Amid significant improvements in narrowing the digital divide, the number of technology-based mental health interventions has increased. A technology-based mode of delivery is important to consider because it can increase patient engagement and should inform program development. This review aimed to assess the mode of technology used for preventing and/or treating perinatal depression and anxiety in Latina and African American women, examine symptom management, and describe participant satisfaction. METHODS: We used PubMed, CINAHL, PsycINFO, PsycARTICLES, EBSCO, and Social Services Abstracts to identify studies that used technology (e.g., smartphones) to prevent and/or treat depression and/or anxiety in Latina and/or African American perinatal women. To be eligible for inclusion, studies must have had at least 50% Latina and/or African American samples. The review was conducted between November 2018 and October 2019, with no set publication start date. RESULTS: Of 152 studies reviewed, six met the inclusion criteria. Four studies included African American women; two studies had samples that were mostly composed of Latina women. Three studies used telephone/smartphone (e.g., text messaging) and three implemented internet-based interventions. All studies addressed depression; one focused on anxiety. The findings demonstrated participant satisfaction and promise for symptom management. DISCUSSION: Despite the limited number of studies that used technology to engage Latina and African American perinatal women, the results suggest that these women were willing to participate in digital interventions to address perinatal depression and anxiety.

Improved yield, fruit quality, and salt resistance in tomato co-overexpressing LeNHX2 and SlSOS2 genes.

The K+, Na+/H+ antiporter LeNHX2 and the regulatory kinase SlSOS2 are important determinants of salt tolerance in tomato plants and their fruit production ability. In this work, we have analyzed the effects of LeNHX2 and SlSOS2 co-overexpression on fruit production, quality in tomato plants (Solanum lycopersicum L. cv. MicroTom), and analyzed physiological parameters related to salt tolerance. Plants overexpressing LeNHX2, SlSOS2 or both were grown in greenhouse. They were treated with 125 mM NaCl or left untreated and their salt tolerance was analyzed in terms of plant biomass and fruit yield. Under NaCl cultivation conditions, transgenic tomato plants overexpressing either SlSOS2 or LeNHX2 or both grew better and showed a higher biomass compared to their wild-type plants. Proline, glucose and protein content in leaves as well as pH and total soluble solid (TSS) in fruits were analyzed. Our results indicate that salinity tolerance of transgenic lines is associated with an increased proline, glucose and protein content in leaves of plants grown either with or without NaCl. Salt treatment significantly reduced yield, pH and TSS in fruits of WT plants but increased yield, pH and TSS in fruits of transgenic plants, especially those overexpressing both LeNHX2 and SlSOS2. All these results indicate that the co-overexpression of LeNHX2 and SlSOS2 improve yield and fruit quality of tomato grown under saline conditions.

Assessing the effectiveness of AS-48 in experimental mice models of Chagas' disease.

OBJECTIVES: We report the in vivo trypanocidal activity of the bacteriocin AS-48 (lacking toxicity), which is produced by Enterococcus faecalis, against the flagellated protozoan Trypanosoma cruzi, the aetiological agent of Chagas' disease. METHODS: We determined the in vivo activity of AS-48 against the T. cruzi Arequipa strain in BALB/c mice (in both acute and chronic phases of Chagas' disease). We evaluated the parasitaemia, the reactivation of parasitaemia after immunosuppression and the nested parasites in the chronic phase by PCR in target tissues. RESULTS: AS-48 reduced the parasitaemia profile in acute infection and showed a noteworthy reduction in the parasitic load in chronic infection after immunosuppression according to the results obtained by PCR (double-checking to demonstrate cure). CONCLUSIONS: AS-48 is a promising alternative that provides a step forward in the development of a new therapy against Chagas' disease.

Overexpression of LeNHX4 improved yield, fruit quality and salt tolerance in tomato plants (Solanum lycopersicum L.).

The function of the tomato K+, Na+/H+ antiporter LeNHX4 has been analyzed using 35S-driven gene construct for overexpressing a histagged LeNHX4 protein in Solanum lycopersicum L. Compared to wild-type plants, the expression of LeNHX4 was enhanced in most of plants transformed with a gene construct for LeNHX4 overexpression although some plants showed a decreased LeNHX4 expression. Overexpression of LeNHX4 was associated to an increased fruit size while silencing of this gene was related to a decreased fruit size. We have investigated the effect of LeNHX4 overexpression on fruit production and quality and we have also evaluated salt tolerance in two different overexpression lines by measuring proline, protein and glucose concentrations in tomato leaves grown either under control (0 mM NaCl) or saline (125 mM NaCl) conditions. Plants overexpressing LeNHX4 showed a higher amount of fruits than WT plants and accumulated higher contents of sugars and cations (Na+ and K+). The application of 125 mM NaCl, affected negatively fruit production and quality of WT plants. However the transgenic lines overexpressing LeNXH4 increased fruit quality and yield. In relation to salt tolerance, overexpression lines showed higher levels of leaf proline, glucose and proteins under NaCl treatment. The overexpression of LeNHX4 in tomato plants, improved salinity tolerance and increased fruit yield and quality under both normal and salinity stress conditions.

In Vivo Biological Evaluation of a Synthetic Royleanone Derivative as a Promising Fast-Acting Trypanocidal Agent by Inducing Mitochondrial-Dependent Necrosis.

The life-long and life-threatening Chagas disease is one of the most neglected tropical diseases caused by the protozoan parasite Trypanosoma cruzi. It is a major public health problem in Latin America, as six to seven million people are infected, being the principal cause of mortality in many endemic regions. Moreover, Chagas disease has become widespread due to migrant populations. Additionally, there are no vaccines nor effective treatments to fight the disease because of its long-term nature and complex pathology. Therefore, these facts emphasize how crucial the international effort for the development of new treatments against Chagas disease is. Here, we present the in vitro and in vivo trypanocidal activity of some oxygenated abietane diterpenoids and related compounds. The 1,4-benzoquinone 15, not yet reported, was identified as a fast-acting trypanocidal drug with efficacy against different strains in vitro and higher activity and lower toxicity than benznidazole in both phases of murine Chagas disease. The mode of action was also evaluated, suggesting that quinone 15 kills T. cruzi by inducing mitochondrion-dependent necrosis through a bioenergetics collapse caused by a mitochondrial membrane depolarization and iron-containing superoxide dismutase inhibition. Therefore, the abietane 1,4-benzoquinone 15 can be considered as a new candidate molecule for the development of an appropriate and commercially accessible anti-Chagas drug.

Repositioning of leishmanicidal [1,2,3]Triazolo[1,5-a]pyridinium salts for Chagas disease treatment: Trypanosoma cruzi cell death involving mitochondrial membrane depolarisation and Fe-SOD inhibition.

Trypanosomatidae is a family of unicellular parasites belonging to the phylum Euglenozoa, which are causative agents in high impact human diseases such as Leishmaniasis, Chagas disease and African sleeping sickness. The impact on human health and local economies, together with a lack of satisfactory chemotherapeutic treatments and effective vaccines, justifies stringent research efforts to search for new disease therapies. Here, we present in vitro trypanocidal activity data and mode of action data, repositioning leishmanicidal [1,2,3]Triazolo[1,5-a]pyridinium salts against Trypanosoma cruzi, the aetiological agent of Chagas disease. This disease is one of the most neglected tropical diseases and is a major public health issue in Central and South America. The disease affects approximately 6-7 million people and is widespread due to increased migratory movements. We screened a suite of leishmanicidal [1,2,3]Triazolo[1,5-a]pyridinium salt compounds, of which compounds 13, 20 and 21 were identified as trypanocidal drugs. These compounds caused cell death in a mitochondrion-dependent manner through a bioenergetic collapse. Moreover, compounds 13 and 20 showed a remarkable inhibition of iron superoxide dismutase activity of T. cruzi, a key enzyme in the protection from the damage produced by oxidative stress.

Effective Tetradentate Compound Complexes against Leishmania spp. that Act on Critical Enzymatic Pathways of These Parasites.

The spectrum and efficacy of available antileishmanial drugs is limited. In the present work we evaluated in vitro the antiproliferative activity of 11 compounds based on tetradentate polyamines compounds against three Leishmania species (L. braziliensis, L. donovani and L. infantum) and the possible mechanism of action. We identified six compounds (3, 5, 6, 7, 8 and 10) effective against all three Leishmania spp both on extracellular and intracellular forms. These six most active leishmanicidal compounds also prevent the infection of host cells. Nevertheless, only compound 7 is targeted against the Leishmania SOD. Meanwhile, on the glucose metabolism the tested compounds have a species-specific effect on Leishmania spp.: L. braziliensis was affected mainly by 10 and 8, L. donovani by 7, and L. infantum by 5 and 3. Finally, the cellular ultrastructure was mainly damaged by 11 in the three Leishmania spp. studied. These identified antileishmania candidates constitute a good alternative treatment and will be further studied.

Envelope K+/H+ Antiporters AtKEA1 and AtKEA2 Function in Plastid Development.

It is well established that thylakoid membranes of chloroplasts convert light energy into chemical energy, yet the development of chloroplast and thylakoid membranes is poorly understood. Loss of function of the two envelope K(+)/H(+) antiporters AtKEA1 and AtKEA2 was shown previously to have negative effects on the efficiency of photosynthesis and plant growth; however, the molecular basis remained unclear. Here, we tested whether the previously described phenotypes of double mutant kea1kea2 plants are due in part to defects during early chloroplast development in Arabidopsis (Arabidopsis thaliana). We show that impaired growth and pigmentation is particularly evident in young expanding leaves of kea1kea2 mutants. In proliferating leaf zones, chloroplasts contain much lower amounts of photosynthetic complexes and chlorophyll. Strikingly, AtKEA1 and AtKEA2 proteins accumulate to high amounts in small and dividing plastids, where they are specifically localized to the two caps of the organelle separated by the fission plane. The unusually long amino-terminal domain of 550 residues that precedes the antiport domain appears to tether the full-length AtKEA2 protein to the two caps. Finally, we show that the double mutant contains 30% fewer chloroplasts per cell. Together, these results show that AtKEA1 and AtKEA2 transporters in specific microdomains of the inner envelope link local osmotic, ionic, and pH homeostasis to plastid division and thylakoid membrane formation.

Effect of a sustained difference in hemodialytic clearance on the plasma levels of p-cresol sulfate and indoxyl sulfate.

BACKGROUND: The protein-bound solutes p-cresol sulfate (PCS) and indoxyl sulfate (IS) accumulate to high plasma levels in renal failure and have been associated with adverse events. The clearance of these bound solutes can be altered independently of the urea clearance by changing the dialysate flow and dialyzer size. This study tested whether a sustained difference in clearance would change the plasma levels of PCS and IS. METHODS: Fourteen patients on thrice-weekly nocturnal hemodialysis completed a crossover study of two periods designed to achieve widely different bound solute clearances. We compared the changes in pre-dialysis plasma PCS and IS levels from baseline over the course of the two periods. RESULTS: The high-clearance period provided much higher PCS and IS clearances than the low-clearance period (PCS: 23 ± 4 mL/min versus 12 ± 3 mL/min, P < 0.001; IS: 30 ± 5 mL/min versus 17 ± 4 mL/min, P < 0.001). Despite the large difference in clearance, the high-clearance period did not have a different effect on PCS levels than the low-clearance period [from baseline, high: +11% (-5, +37) versus low: -8% (-18, +32), (median, 25th, 75th percentile), P = 0.50]. In contrast, the high-clearance period significantly lowered IS levels compared with the low-clearance period [from baseline, high: -4% (-17, +1) versus low: +22% (+14, +31), P < 0.001). The amount of PCS removed in the dialysate was significantly greater at the end of the high-clearance period [269 (206, 312) versus 199 (111, 232) mg per treatment, P < 0.001], while the amount of IS removed was not different [140 (87, 196) versus 116 (89, 170) mg per treatment, P = 0.15]. CONCLUSIONS: These findings suggest that an increase in PCS generation prevents plasma levels from falling when the dialytic clearance is increased. Suppression of solute generation may be required to reduce plasma PCS levels in dialysis patients.

In vitro and in vivo identification of tetradentated polyamine complexes as highly efficient metallodrugs against Trypanosoma cruzi.

In order to identify new compounds to treat Chagas disease during the acute phase with higher activity and lower toxicity than the reference drug benznidazole (Bz), a series of tetraamine-based compounds was prepared and their trypanocidal effects against Trypanosoma cruzi were evaluated by light microscopy through the determination of IC50 values. Cytotoxicity was determined by flow cytometry assays against Vero cells. In vivo assays were performed in BALB/c mice, in which the parasitemia levels were quantified by fresh blood examination; the assignment of a cure was determined by PCR and reactivation of blood parasitemia levels after immunosuppression. The mechanism of action was elucidated at metabolic and ultra-structural levels by (1)H NMR and TEM studies. Finally, as tetraamines are potentially capable of casuing oxidative damage in the parasites, the study was completed by assessing their activity as potential iron superoxide dismutase (Fe-SOD) and trypanothione reductase (TR) inhibitors. High-selectivity indexes observed in vitro were the basis of promoting three of the tested compounds to in vivo assays. The tests on the murine model for the acute phase of Chagas disease showed better parasitemia inhibition values than those found for Bz. Tetraamines 2 and 3 induced a remarkable decrease in the reactivation of parasitemia after immunosuppression and curative rates of 33 and 50%, respectively. Tetraamine 3 turned out to be a great inhibitor of Fe-SOD and TR. The high anti-parasitic activity and low toxicity render these tetraamines appropriate molecules for the development of an affordable anti-Chagas agent.