Discovery of Arylpiperazines with Broad-Spectrum Antimicrobial Activity and Favorable Pharmacokinetic Profiles.

Microorganisms can induce diseases with significant clinical implications for human health. Multidrug-resistant microorganisms have been on the rise worldwide over the past few decades, and no new antibiotics have been introduced to the market in a considerable amount of time. Such situation highlights the urgency of discovering new antimicrobial drugs to address this pressing issue. Therefore, the objective of this study was to identify bioactive compounds against 15 species of bacteria and 5 species of fungi of clinical relevance through in vitro screening of 58 synthetic compounds from four chemical classes of our internal library of synthetic compounds. Our findings highlight arylpiperazines 18, 20, 26, 27, and 29, and the aminothiazole 50, as potent broad-spectrum antimicrobials (MICs = 12.5 - 15.6 mg.mL-1) against clinically relevant bacteria and fungi. Additionally, these compounds displayed low cytotoxicity against various host cells and a favorable in vitro pharmacokinetic profile for oral administration. Indeed, all six showed adequate lipophilicity, high gastrointestinal permeability, metabolic stability in human and mouse liver microsomes, and satisfactory aqueous solubility. Thus, they emerge as promising starting points for hit-to-lead studies towards new antibacterial and antifungal agents, especially against Staphylococcus epidermidis, Staphylococcus aureus, Lactobacillus paracasei and Candida orthopsilosis.

Life table study of Rachiplusia nu (Lepidoptera: Noctuidae) on different food sources and artificial diet.

Rachiplusia nu Guenée is a polyphagous species able to develop on several cultivated and non-cultivated host plants. However, basic life history information about this pest on hosts is scarce. In this study, R. nu larvae did not survive on leaves of non-Bt corn, wheat, Bt cotton that expresses proteins Cry1Ac+Cry2Ab2 or on Intacta2 Xtend soybean that expresses the Cry1A.105/Cry2Ab2/Cry1Ac proteins. Rachiplusia nu showed a viable egg-to-adult biological cycle (54%-66.3%) on non-Bt soybean, sunflower, canola, vetch, Persian clover, alfalfa, bean, and forage turnip hosts, similar to larvae raised on the artificial diet. In addition, R. nu was unable to complete larval development on non-Bt cotton, and only 45.2% of R. nu larvae reached the pupal stage when fed leaves of intacta RR2 PRO soybean that expresses the Cry1Ac protein. Larval and pupal mass of surviving insects on Cry1Ac soybean leaves were also lower (larval: 0.104 g; pupal: 0.099 g) in relation to other food sources (larval: 0.165-0.189 g; pupal: 0.173-0.192 g). The total fecundity of R. nu on Cry1Ac soybean leaves was ≈65% lower in relation to other food sources. This fact caused ≈60% the net reproductive rate (Ro) and intrinsic rate of increase (rm) when compared to other food sources. Our findings indicate that the Cry1Ac soybean negatively affects the biological parameters of R. nu. Non-Bt soybean, sunflower, canola, vetch, Persian clover, alfalfa, bean, and forage turnip are viable food sources for the survival and development of R. nu.

Neglected Tropical Diseases: A Chemoinformatics Approach for the Use of Biodiversity in Anti-Trypanosomatid Drug Discovery.

The development of new treatments for neglected tropical diseases (NTDs) remains a major challenge in the 21st century. In most cases, the available drugs are obsolete and have limitations in terms of efficacy and safety. The situation becomes even more complex when considering the low number of new chemical entities (NCEs) currently in use in advanced clinical trials for most of these diseases. Natural products (NPs) are valuable sources of hits and lead compounds with privileged scaffolds for the discovery of new bioactive molecules. Considering the relevance of biodiversity for drug discovery, a chemoinformatics analysis was conducted on a compound dataset of NPs with anti-trypanosomatid activity reported in 497 research articles from 2019 to 2024. Structures corresponding to different metabolic classes were identified, including terpenoids, benzoic acids, benzenoids, steroids, alkaloids, phenylpropanoids, peptides, flavonoids, polyketides, lignans, cytochalasins, and naphthoquinones. This unique collection of NPs occupies regions of the chemical space with drug-like properties that are relevant to anti-trypanosomatid drug discovery. The gathered information greatly enhanced our understanding of biologically relevant chemical classes, structural features, and physicochemical properties. These results can be useful in guiding future medicinal chemistry efforts for the development of NP-inspired NCEs to treat NTDs caused by trypanosomatid parasites.

Factor analytic selection tools and environmental feature-integration enable holistic decision-making in Eucalyptus breeding.

Understanding the genotype-by-environment interaction (GEI) and considering it in the selection process is a sine qua non condition for the expansion of Brazilian eucalyptus silviculture. This study's objective is to select high-performance and stable eucalyptus clones based on a novel selection index that considers the Factor Analytic Selection Tools (FAST) and the clone's reliability. The investigation explores the nuances interplay of GEI and extends its insights by scrutinizing the relationship between latent factors and real environmental features. The analysis, conducted across seven trials in five Brazilian states involving 78 clones, employs FAST. The clonal selection was performed using an extended FAST index weighted by the clone's reliability. Further insights about GEI emerge from the integration of factor loadings with 25 environmental features through a principal component analysis. Ten clones, distinguished by high performance, stability, and reliability, have been selected across the target population of environments. The environmental features most closely associated with factor loadings, encompassing air temperature, radiation, and soil characteristics, emerge as pivotal drivers of GEI within this dataset. This study contributes insights to eucalyptus breeders, equipping them to enhance decision-making by harnessing a holistic understanding-from the genotypes under evaluation to the diverse environments anticipated in commercial plantations.

OxInflammation Affects Transdifferentiation to Myofibroblasts, Prolonging Wound Healing in Diabetes: A Systematic Review.

Skin wounds, primarily in association with type I diabetes mellitus, are a public health problem generating significant health impacts. Therefore, identifying the main pathways/mechanisms involved in differentiating fibroblasts into myofibroblasts is fundamental to guide research into effective treatments. Adopting the PRISMA guidelines, this study aimed to verify the main pathways/mechanisms using diabetic murine models and analyze the advances and limitations of this area. The Medline (PubMed), Scopus, and Web of Science platforms were used for the search. The studies included were limited to those that used diabetic murine models with excisional wounds. Bias analysis and methodological quality assessments were undertaken using the SYRCLE bias risk tool. Eighteen studies were selected. The systematic review results confirm that diabetes impairs the transformation of fibroblasts into myofibroblasts by affecting the expression of several growth factors, most notably transforming growth factor beta (TGF-beta) and NLRP3. Diabetes also compromises pathways such as the SMAD, c-Jun N-terminal kinase, protein kinase C, and nuclear factor kappa beta activating caspase pathways, leading to cell death. Furthermore, diabetes renders the wound environment highly pro-oxidant and inflammatory, which is known as OxInflammation. As a consequence of this OxInflammation, delays in the collagenization process occur. The protocol details for this systematic review were registered with PROSPERO: CRD42021267776.

Gait analysis of patients undergoing knee endoprosthesis: functional differences between tibia and femur resections.

With the improvement in survival of patients undergoing knee reconstructive surgeries, the functional parameter became widely studied heading optimize and minimize motor sequelae. In patients undergoing knee endoprosthesis, proximal tibial or distal femoral resections affect the functioning of the knee extensor mechanism, with possible repercussions on gait. Seventeen patients were selected, divided into two groups, undergoing distal femoral or proximal tibial resection, and gait analysis examination was performed. Changes in gait velocity, cadence, step length, and alterations in the support and balance phase were observed. No major statistically significant differences were found in the kinetic and kinematic parameters between the operated groups. The study corroborates that although tibial resections have a higher theoretical risk of compromising the extensor mechanism, such data were not observed in the analyzed sample.

Morphological comparison of the larynx and trachea of Chelonia mydas (Linnaeus, 1758), Caiman yacare (Daudin, 1802) and Caiman latirostris (Daudin, 1802).

The larynx is in the lower respiratory tract and has the function of protecting the airways, controlling, and modulating breathing, assisting the circulatory system, and vocalizing. This study aims to describe the anatomy and histology of the skeleton of the larynx and trachea of the species Chelonia mydas, Caiman yacare and Caiman latirostris. The study was conducted at the Federal University of Espírito Santo (UFES), using nine specimens of Ch. mydas, 20 of Ca. yacare and four of Ca. latirostris. Samples of the larynx and trachea were collected, fixed, and sent for dissection of the structures and subsequent macroscopic analysis. For histology, samples were processed by the routine paraffin embedding method and stained with hematoxylin-eosin and Verhoeff. For the three species, two arytenoid cartilages, a cricoid cartilage, a hyoid apparatus composed of a base and two horns were found. In Ch. mydas, two structures called thyroid wings were observed, not found in crocodilians. The trachea of crocodilians presented incomplete tracheal rings and musculature, while the trachea of Ch. mydas presented complete tracheal rings. Histologically, the entire cartilaginous skeleton of the larynx of the three species, as well as the tracheal rings, are constituted by hyaline cartilage.

Lipids in Insect Reproduction: Where, How, and Why.

Modern insects have inhabited the earth for hundreds of millions of years, and part of their successful adaptation lies in their many reproductive strategies. Insect reproduction is linked to a high metabolic rate that provides viable eggs in a relatively short time. In this context, an accurate interplay between the endocrine system and the nutrients synthetized and metabolized is essential to produce healthy offspring. Lipids guarantee the metabolic energy needed for egg formation and represent the main energy source consumed during embryogenesis. Lipids availability is tightly regulated by a complex network of endocrine signals primarily controlled by the central nervous system (CNS) and associated endocrine glands, the corpora allata (CA) and corpora cardiaca (CC). This endocrine axis provides hormones and neuropeptides that significatively affect tissues closely involved in successful reproduction: the fat body, which is the metabolic center supplying the lipid resources and energy demanded in egg formation, and the ovaries, where the developing oocytes recruit lipids that will be used for optimal embryogenesis. The post-genomic era and the availability of modern experimental approaches have advanced our understanding of many processes involved in lipid homeostasis; therefore, it is crucial to integrate the findings of recent years into the knowledge already acquired in the last decades. The present chapter is devoted to reviewing major recent contributions made in elucidating the impact of the CNS/CA/CC-fat body-ovary axis on lipid metabolism in the context of insect reproduction, highlighting areas of fruitful research.

Synthesis and Anti-Trypanosoma cruzi Activity of 3-Cyanopyridine Derivatives.

Chagas disease (CD) is a parasitic neglected tropical disease (NTD) caused by the protozoan Trypanosoma cruzi that affects 6 million people worldwide, often resulting in financial burden, morbidity, and mortality in endemic regions. Given a lack of highly efficient and safe treatments, new, affordable, and fit-for-purpose drugs for CD are urgently needed. In this work, we present a hit-to-lead campaign for novel cyanopyridine analogues as antichagasic agents. In a phenotypic screening against intracellular T. cruzi, hits 1 and 2 were identified and displayed promising potency combined with balanced physicochemical properties. As part of the Lead Optimization Latin America consortium, a set of 40 compounds was designed, synthesized, and tested against T. cruzi intracellular amastigotes and relevant human cell lines. The structural modifications were focused on three positions: cyanopyridine core, linker, and right-hand side. The ADME properties of selected compounds, lipophilicity, kinetic solubility, permeability, and liver microsomal stability, were evaluated. Compounds 1-9 displayed good potency (EC50T. cruzi amastigote <1 µM), and most compounds did not present significant cytotoxicity (CC50 MRC-5 = 32-64 µM). Despite the good balance between potency and selectivity, the antiparasitic activity of the series appeared to be driven by lipophilicity, making the progression of the series unfeasible due to poor ADME properties and potential promiscuity issues.

Evaluation and discovery of novel benzothiazole derivatives as promising hits against Leishmania infantum.

An early exploration of the benzothiazole class against two kinetoplastid parasites, Leishmania infantum and Trypanosoma cruzi, has been performed after the identification of a benzothiazole derivative as a suitable antileishmanial initial hit. The first series of derivatives focused on the acyl fragment of its class, evaluating diverse linear and cyclic, alkyl and aromatic substituents, and identified two other potent compounds, the phenyl and cyclohexyl derivatives. Subsequently, new compounds were designed to assess the impact of the presence of diverse substituents on the benzothiazole ring or the replacement of the endocyclic sulfur by other heteroatoms. All compounds showed relatively low cytotoxicity, resulting in decent selectivity indexes for the most active compounds. Ultimately, the in vitro ADME properties of these compounds were assessed, revealing a satisfying water solubility, gastrointestinal permeability, despite their low metabolic stability and high lipophilicity. Consequently, compounds 5 and 6 were identified as promising hits for further hit-to-lead exploration within this benzothiazole class against L. infantum, thus providing promising starting points for the development of antileishmanial candidates.

Exploring the impact of high-energy diets on cattle: Insights into subacute rumen acidosis, insulin resistance, and hoof health.

Cattle lameness remains a significant concern, causing economic losses and compromising animal welfare. Claw horn lesions have been identified as a major cause of lameness in dairy cows, but their correlation with high-energy diets and ruminal acidosis remains unclear. Hence, the primary objective of this study was to assess the effects of a high-starch diet and a conventional diet on the rumen environment, acute-phase proteins, and metabolic alterations, with a particular focus on insulin resistance and the consequent implications for the histology of the hooves in Holstein steers. A total of 16 animals were divided into the high-starch (HS; 37% starch) and conventional (CON; 16.8% starch) groups. Glucose tolerance tests (GTT), blood analyses, rumen fluid analyses, and histological evaluations of the hoof tissue were conducted over a 102-d experimental period. The HS group showed a lower ruminal pH than the CON group, and with values indicating SARA. The plasma glucose and IGF-1 concentrations were higher in the HS group, suggesting an anabolic state. Both groups exhibited an increase in the insulin area under the curve (AUC) after the GTT on d 102. Histological analysis of the hooves showed a reduction in the length and width of the epidermal lamella in both groups. We found a significant negative correlation between the insulin AUC and the length and width of the epidermal lamella. Because both groups were similarly affected, the hypothesis that histological alterations were caused by the experimental diets still needs confirmation. Additionally, the development of SARA was not essential for the observed histological changes in the hoof. Further studies are warranted to thoroughly investigate the role of insulin and IGF-1 imbalances in claw health.

Selecting tropical wheat genotypes through combining ability analysis.

The selection of parents to originate promising base populations, as well as the knowledge of the gene effects controlling agronomic traits by means of diallel, are useful to drive genetic gains in Brazilian tropical wheat breeding programs. The goals of this study were to select tropical wheat parents with a high frequency of favorable alleles and segregating populations with high potential to originate superior progenies through partial diallel analysis. Thus, 14 parents were divided in two groups and crossed in a 7 × 7 partial diallel scheme to originate 49 F1 combinations. After obtaining F2 generation, the populations and the parents were evaluated in the field in the summer of 2021. Days for heading, plant height, rust and yellow spot resistance, and grain yield were evaluated. The data were subjected to partial diallel analysis. There were significant effects of general combining ability for all traits. The specific combining ability effect was significant for days for heading and plant height. The additive gene effects were predominant over the non-additive ones. The parents with the highest frequency of favorable alleles for the traits evaluated were selected in each group. Four populations with high genetic potential to originate superior progenies were selected.

Daylong acoustic recordings of grazing and rumination activities in dairy cows.

Monitoring livestock feeding behavior may help assess animal welfare and nutritional status, and to optimize pasture management. The need for continuous and sustained monitoring requires the use of automatic techniques based on the acquisition and analysis of sensor data. This work describes an open dataset of acoustic recordings of the foraging behavior of dairy cows. The dataset includes 708 h of daily records obtained using unobtrusive and non-invasive instrumentation mounted on five lactating multiparous Holstein cows continuously monitored for six non-consecutive days in pasture and barn. Labeled recordings precisely delimiting grazing and rumination bouts are provided for a total of 392 h and for over 6,200 ingestive and rumination jaw movements. Companion information on the audio recording quality and expert-generated labels is also provided to facilitate data interpretation and analysis. This comprehensive dataset is a useful resource for studies aimed at exploring new tools and solutions for precision livestock farming.

Correlation between ischemic stroke topography and female urinary incontinence.

AIM: To investigate the association between ischemic stroke topography and the onset of urinary incontinence (UI); to evaluate predictors of post-stroke UI in women. METHOD: We prospectively followed up a cohort of women with ischemic stroke confirmed by clinical and computed tomography (CT) or magnetic resonance imaging (MRI) scans findings. Participants were subjected to interview, clinical evaluation, and urodynamic study if needed at 6 months post-stroke and divided in continent and incontinent groups. Non-parametric tests compared the baseline characteristics among the groups and determined association between post-stroke UI and the brain sites of injury. Logistic regression analysis determined predictors of post-stroke UI. Significance level at 5 % was set. RESULTS: 162 S-women were included: 128 (79 %) continent and 34 (21 %) incontinent. Frontal lobe lesions were higher in the incontinent group (82.9 % versus 51.2 %, p = 0.001); lesions in the parietal lobe and the left cerebral hemisphere were higher in the continent group (40.9 % versus 20 %, p = 0.023; and 61.4 % versus 40 %, p = 0.024, respectively). Frontal lobe injury [RR 3.68 (CI 1.2-11.2)], body mass index (BMI) [RR1.16 (CI 1.062-1.266)] and number of vaginal deliveries [RR 1.358 (CI 1.163-1.585)] are risk factors for post-stroke UI. Left parietal lobe injury is less likely to occur in continent women after 6 months [RR 0.168 (CI 0.029-0.981; p = 0.048)]. CONCLUSION: There is a correlation between the topography of the ischemic stroke and the onset of UI. Frontal lobe lesion, BMI and number of vaginal deliveries are predictors of post-stroke UI.

Coxiella co-opts the Glutathione Peroxidase 4 to protect the host cell from oxidative stress-induced cell death.

The causative agent of human Q fever, Coxiella burnetii, is highly adapted to infect alveolar macrophages by inhibiting a range of host responses to infection. Despite the clinical and biological importance of this pathogen, the challenges related to genetic manipulation of both C. burnetii and macrophages have limited our knowledge of the mechanisms by which C. burnetii subverts macrophages functions. Here, we used the related bacterium Legionella pneumophila to perform a comprehensive screen of C. burnetii effectors that interfere with innate immune responses and host death using the greater wax moth Galleria mellonella and mouse bone marrow-derived macrophages. We identified MceF (Mitochondrial Coxiella effector protein F), a C. burnetii effector protein that localizes to mitochondria and contributes to host cell survival. MceF was shown to enhance mitochondrial function, delay membrane damage, and decrease mitochondrial ROS production induced by rotenone. Mechanistically, MceF recruits the host antioxidant protein Glutathione Peroxidase 4 (GPX4) to the mitochondria. The protective functions of MceF were absent in primary macrophages lacking GPX4, while overexpression of MceF in human cells protected against oxidative stress-induced cell death. C. burnetii lacking MceF was replication competent in mammalian cells but induced higher mortality in G. mellonella, indicating that MceF modulates the host response to infection. This study reveals an important C. burnetii strategy to subvert macrophage cell death and host immunity and demonstrates that modulation of the host antioxidant system is a viable strategy to promote the success of intracellular bacteria.

Molecular basis of two pyrimidine-sulfonylurea herbicides: from supramolecular arrangement to acetolactate synthase inhibition.

CONTEXT: The design and synthesis of safe and highly active sulfonylurea herbicides is still a challenge. Therefore, following some principles of structure-activity relationship (SAR) of sulfonylurea herbicides, this work focuses on evaluating two sulfonylurea derivatives bearing electron-withdrawing substituents, namely, -(CO)OCH3 and -NO2 on the aryl group, on herbicidal activity. To understand the effects caused by the substituent groups, the molecular and electronic structures of the sulfonylureas were evaluated by density functional theory. Likewise, the crystalline supramolecular arrangements of both compounds were analyzed by Hirshfeld surface, QTAIM, and NBO, with the aim of verifying changes in intermolecular interactions caused by substituent groups. Finally, through a toxicophoric analysis, we were able to predict the interacting groups in their biological target, acetolactate synthase, and verify the interactions with the binding site. METHODS: All theoretical calculations were conducted using the highly parameterized empirical exchange-correlation functional M06-2X accompanied by the diffuse and polarized basis set 6-311++G(d,p). The atomic coordinates were obtained directly from the crystalline structures, and from the energies of the frontier molecular orbitals (HOMO and LUMO), chemical descriptors were obtained that indicated the influence of the functional groups in the sulfonylureas on the reactivity of the molecules. The intermolecular interactions in the crystals were analyzed using the Hirshfeld, QTAIM, and NBO surfaces. Toxicophoric modeling was performed by the PharmaGist webserver and molecular docking calculations were performed by the GOLD 2022.1.0 software package so that the ligand was fitted to the binding site in a 10 Å sphere. For this, genetic algorithm parameters were used using the ChemPLP scoring function for docking and ASP for redocking.

Simultaneous silencing of juvenile hormone metabolism genes through RNAi interrupts metamorphosis in the cotton boll weevil.

The cotton boll weevil (CBW) (Anthonomus grandis) is one of the major insect pests of cotton in Brazil. Currently, CBW control is mainly achieved by insecticide application, which is costly and insufficient to ensure effective crop protection. RNA interference (RNAi) has been used in gene function analysis and the development of insect control methods. However, some insect species respond poorly to RNAi, limiting the widespread application of this approach. Therefore, nanoparticles have been explored as an option to increase RNAi efficiency in recalcitrant insects. Herein, we investigated the potential of chitosan-tripolyphosphate (CS-TPP) and polyethylenimine (PEI) nanoparticles as a dsRNA carrier system to improve RNAi efficiency in the CBW. Different formulations of the nanoparticles with dsRNAs targeting genes associated with juvenile hormone metabolism, such as juvenile hormone diol kinase (JHDK), juvenile hormone epoxide hydrolase (JHEH), and methyl farnesoate hydrolase (MFE), were tested. The formulations were delivered to CBW larvae through injection (0.05-2 µg), and the expression of the target genes was evaluated using RT-qPCR. PEI nanoparticles increased targeted gene silencing compared with naked dsRNAs (up to 80%), whereas CS-TPP-dsRNA nanoparticles decreased gene silencing (0%-20%) or led to the same level of gene silencing as the naked dsRNAs (up to 50%). We next evaluated the effects of targeting a single gene or simultaneously targeting two genes via the injection of naked dsRNAs or dsRNAs complexed with PEI (500 ng) on CBW survival and phenotypes. Overall, the gene expression analysis showed that the treatments with PEI targeting either a single gene or multiple genes induced greater gene silencing than naked dsRNA (∼60%). In addition, the injection of dsJHEH/JHDK, either naked or complexed with PEI, significantly affected CBW survival (18% for PEI nanoparticles and 47% for naked dsRNA) and metamorphosis. Phenotypic alterations, such as uncompleted pupation or malformed pupae, suggested that JHEH and JHDK are involved in developmental regulation. Moreover, CBW larvae treated with dsJHEH/JHDK + PEI (1,000 ng/g) exhibited significantly lower survival rate (55%) than those that were fed the same combination of naked dsRNAs (30%). Our findings demonstrated that PEI nanoparticles can be used as an effective tool for evaluating the biological role of target genes in the CBW as they increase the RNAi response.

Sex differences in the relationship between hepatic steatosis, mood and anxiety disorders.

OBJECTIVE: To investigate the association between non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), mental symptoms (mood, anxiety disorders and distress) by sex. METHODS: This a cross-sectional study performed in working-age adults from a Health Promotion Center (primary care) in São Paulo, Brazil. Self-reported mental symptoms from rating scales (21-item Beck Anxiety Inventory, Patient Health Questionnaire-9, and K6 distress scale) were evaluated by hepatic steatosis (NAFLD and ALD). Logistic regression models estimated the association between hepatic steatosis subtypes and mental symptoms by Odds ratios (OR) adjusted by confounders in the total sample and sex stratified. RESULTS: Among 7241 participants (70.5% men, median age: 45 years), the frequency of steatosis was of 30.7% (25.1% NAFLD), being higher in men than women (70.5% vs. 29.5%, p < 0.0001), regardless of the steatosis subtype. Metabolic risk factors were similar in both subtypes of steatosis, but not mental symptoms. Overall, NAFLD was inversely associated with anxiety (OR = 0.75, 95%CI 0.63-0.90) and positively associated with depression (OR = 1.17, 95%CI 1.00-1.38). On the other hand, ALD was positively associated with anxiety (OR = 1.51; 95%CI 1.15-2.00). In sex-stratified analyses, only men presented an association of anxiety symptoms with NAFLD (OR = 0.73; 95%CI 0.60-0.89) and ALD (OR = 1.60; 95%CI 1.18-2.16). CONCLUSIONS: The complex association between different types of steatosis (NAFLD and ALD), mood and anxiety disorders indicates the need for a deeper understanding of their common causal pathways.

Effects of heat stress on sperm quality of French Bulldogs.

This study aimed to evaluate the effects of heat stress (HS) and its duration on semen quality, serum testosterone, pulsatility and resistibility index of the testicular artery of French Bulldogs. Eight male French Bulldogs, 3-7 years old, 12.63 ± 1.8 Kg were adapted and trained for two months. Room temperature was 21 °C. Semen was collected by digital stimulation. The median of four andrological evaluations was T0. Heat was applied to the scrotum using an electrical heat pad at 40 °C for 11 min. Rectal temperature (RT) and scrotum temperature were evaluated using a mercury thermometer and an infrared thermography camera before and after HS. Semen was evaluated immediately (T1) and after seven (T7), 14 (T14), 21 (T21), 28 (T28) and 60 (T60) days after HS. Semen parameters included macroscopic (volume, color and viscosity) and microscopic (sperm motility and vigor, percentage of morphologically normal or defected spermatozoa, sperm concentration and total number of sperm cells) aspects. A pulsed colored doppler ultrasound was performed on the testicular artery at the spermatic cord and epididymis region before and immediately after HS. Serum testosterone was analyzed before, 48 and 96 h after HS. Data was analyzed by ANOVA using SAS. There was a 1.23 °C increase on RT and a 4.98 °C increase on thermograph after HS. Sperm motility decreased at T1 (P < 0.05) and tended to stay lower at T7 (P = 0.056). It improved at T14, but reduced again at T21 (P < 0.05). At T28 and T60 motility was normal. Vigor was lower at T1 (P < 0.05), normal at T7 and T14, but decreased at T21 (P = 0.054), at T28 and T60 it was not different than T0. Sperm concentration was lower at T1 (P < 0.05) and not different from T0 at other timepoints. Volume color and viscosity were not different. Total sperm per ejaculate was reduced at T1 and T7 (P < 0.05) and tended to be lower at T14 (P = 0.057). T21, T28 and T60 were not different than T0. There was a decrease in normal sperm cells and an increase in defected sperm at T7. There was no difference within T14, T21, T28 and T60. The raise in pathologies at T7 was from an increase in minor defects (P < 0.05). There was no difference in serum concentration of testosterone nor pulsatility and resistivity index before and after HS. In conclusion, induction of HS directly to the testis reduces sperm quality in French Bulldog. This impairment is immediately and transitory.

Hit-to-lead optimization of a 2-aminobenzimidazole series as new candidates for chagas disease.

Chagas disease is a neglected tropical disease caused by Trypanosoma cruzi. Because current treatments present several limitations, including long duration, variable efficacy and serious side effects, there is an urgent need to explore new antitrypanosomal drugs. The present study describes the hit-to-lead optimization of a 2-aminobenzimidazole hit 1 identified through in vitro phenotypic screening of a chemical library against intracellular Trypanosoma cruzi amastigotes, which focused on optimizing potency, selectivity, microsomal stability and lipophilicity. Multiparametric Structure-Activity Relationships were investigated using a set of 277 derivatives. Although the physicochemical and biological properties of the initial hits were improved, a combination of low kinetic solubility and in vitro cytotoxicity against mammalian cells prevented progression of the best compounds to an efficacy study using a mouse model of Chagas disease.