Publications by authors named "F Dos Santos"

2,695 Publications

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Microscopic Detection, Hematological Evaluation and Molecular Characterization of Piroplasms from Naturally Infected Dogs in Rio de Janeiro, Brazil.

Acta Parasitol 2021 Jun 15. Epub 2021 Jun 15.

Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Rua Professor Hernani Mello, São Domingos, Niterói, Rio de Janeiro, 24210-130, Brasil.

Purpose: This study aimed to analyze the frequency of piroplasmids in the blood of dogs in Rio de Janeiro, compare the performance of microscopic techniques, assess the risk factors associated with infections and also molecularly and morphologically characterize the piroplasmids identified.

Methods: In all, 407 blood samples were collected from dogs between 2018 and 2019. These were subjected to microscopic parasitological techniques for thin and thick smears, stained with Giemsa and using a rapid staining kit. The slides were read under an optical microscope and the protozoa were characterized morphometrically. In addition, the blood samples were subjected to molecular characterization for diagnosing piroplasmid species using primers that amplified the gene 18S rRNA.

Results: Piroplasmids were detected in 38 (9.3%) samples. Of these, 33 samples presented nucleotide sequences compatible with Babesia vogeli. Most of the positive samples were young, male, defined breeds dogs that had been attended in clinics in São Gonçalo city. Thrombocytopenia and leukopenia were the hematological alterations more observed in positive samples, but positive samples without alterations were also detected. The sex was the only variable that showed statistical differences. Males dogs being more often infected than females (p < 0.05). The microscope slides mostly showed piriform and oval merozoites measuring greater than 2.5 µm in length, which were compatible with B. vogeli. However, smaller forms were also identified, thus demonstrating the polymorphic nature of this parasite.

Conclusion: Babesia vogeli was detected in blood samples from dogs in the metropolitan cities of Rio de Janeiro by molecular techniques in different parasite morphotypes.
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http://dx.doi.org/10.1007/s11686-021-00426-zDOI Listing
June 2021

Therapeutic effects of β-caryophyllene on proliferative disorders and inflammation of the gerbil prostate.

Prostate 2021 Jun 14. Epub 2021 Jun 14.

Department of Biology, Institute of Biosciences, Humanities and Exact Sciences, São Paulo State University (UNESP), São José do Rio Preto, São Paulo, Brazil.

Background: The prostate is susceptible to changes in androgen levels, which can play an important role in the development of Benign Prostatic Hyperplasia (BPH). Natural compounds have beneficial properties for organisms and can be an important therapeutic strategy in the treatment of diseases. β-Caryophyllene (BCP) is a phytocannabinoid present in several medicinal and food plants species and has shown beneficial effects in different organs. However, little is known about its effects on the prostate. The present study seeks to evaluate the effects of exposure to BCP on the morphophysiology of the ventral prostate of adult gerbils supplemented with testosterone.

Methods: Animals were distributed into four groups (n = 8/group): Intact control (C); β-Caryophyllene (BCP): β-Caryophyllene (50 mg/kg/day); Testosterone (T): animals received subcutaneous injections of Testosterone Cypionate (3 mg/Kg), on alternate days, for one month and were euthanized 30 days supplementation ended; Testosterone and β-Caryophyllene (TBCP): animals were exposed to testosterone cypionate (3 mg/Kg) to induce hyperplastic alterations followed by daily BCP (50 mg/kg). Morphological, biometric, immunohistochemical, and serological analyses were performed.

Results: Proliferative disorders and inflammatory foci were present in the ventral prostate of all experimental groups. An increase in the multiplicity of benign intraepithelial neoplasm and subepithelial inflammatory foci was observed in T group. The incidence of intraluminal inflammatory foci and microinvasive carcinoma was verified only in the T group. Cellular rearrangement and tissue remodeling occurred in the prostate of groups exposed to phytocannabinoids. A reduction was observed in the frequency of PHH3 and Cox2 markers in the prostatic epithelium of TBCP in comparison with T. A decrease in F4/80 and CD163 positive macrophages were also observed in the prostatic stroma of the TBCP group in comparison with T. The results suggest that BCP had favorable effects on BPH, reducing the proliferation and frequency of some inflammatory cells.

Conclusion: BCP impacts the tissue remodeling process in the premalignant prostate environment and that the use of this phytocannabinoid can have a promising effect in the handling of BPH.
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http://dx.doi.org/10.1002/pros.24177DOI Listing
June 2021

Chloride-attachment atmospheric pressure photoionisation for the determination of short-chain chlorinated paraffins by gas chromatography-high-resolution mass spectrometry.

Anal Chim Acta 2021 Aug 22;1172:338673. Epub 2021 May 22.

Department of Chemical Engineering and Analytical Chemistry, University of Barcelona. Av. Diagonal 645, E-08028, Barcelona, Spain; Water Research Institute (IdRA), University of Barcelona, Montalegre 6, E-08001, Barcelona, Spain. Electronic address:

In this work, a new gas chromatography-high-resolution mass spectrometry (GC-HRMS) method based on atmospheric pressure photoionisation (APPI) has been developed for the accurate determination of short-chain chlorinated paraffins (SCCPs) as a reliable alternative to the established methods. To the best of our knowledge, this is the first time these compounds has been analysed by GC-MS using atmospheric pressure photoionisation (APPI). Efficient ionisation of SCCPs was achieved using the new GC-APPI source by the formation of [M+Cl] adduct ions in negative ion mode using dopant-assisted APPI with a mixture of acetone/CCl (3:1, v/v). Operating at a resolution of 70,000 FWHM (full width at half maximum) and monitoring the [M+Cl] adduct ions for each congener group, a selective determination of the SCCPs was achieved, avoiding isobaric interferences between homologue groups with different carbon chain length and chlorination degree. Moreover, the GC-APPI-HRMS response of each congener group was mainly influenced by its concentration and did not depend on the number of chlorine atoms in the molecule as occurs with the GC-MS methods based on the electron-capture negative ionisation (ECNI). Thus, the contribution of the different carbon and chlorine homologue groups in the SCCP mixtures was determined by the internal normalization method, and the quantification was performed independently of the chlorine content of the SCCP standard mixture employed. The developed GC-APPI-HRMS method offers some interesting advantages over the existing methods, particularly the possibility to quantify individual SCCP congener groups, the use of a simple calibration method for quantification, and an important time-saving in the data processing, especially over ECNI-based traditional methods. The GC-APPI-HRMS method allowed the determination of SCCPs at low concentration levels in fish samples with low method limits of detection (17-34 pg g wet weight for total SCCPs), good precision (RSD < 7%) and trueness (relative error < 8%) and can be proposed as a reliable alternative of the established methods for the determination of these pollutants in environmental samples.
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http://dx.doi.org/10.1016/j.aca.2021.338673DOI Listing
August 2021

Systemic Jak1 activation causes extrarenal calcitriol production and skeletal alterations provoking stunted growth.

FASEB J 2021 Jul;35(7):e21721

Institute of Physiology, University of Zurich, Zurich, Switzerland.

Mineral homeostasis is regulated by a complex network involving endocrine actions by calcitriol, parathyroid hormone (PTH), and FGF23 on several organs including kidney, intestine, and bone. Alterations of mineral homeostasis are found in chronic kidney disease and other systemic disorders. The interplay between the immune system and the skeletal system is not fully understood, but cytokines play a major role in modulating calcitriol production and function. One of the main cellular signaling pathways mediating cytokine function is the Janus kinase (JAK)--signal transducer and activator of transcription (STAT) pathway. Here, we used a mouse model (Jak1 ) that resembles a constitutive activating mutation of the Jak1/Stat3 signaling pathway in humans, and shows altered mineral metabolism, with higher fibroblast growth factor 23 (FGF23) levels, lower PTH levels, and higher calcitriol levels. The higher calcitriol levels are probably due to extrarenal calcitriol production. Furthermore, systemic Jak1/Stat3 activation led to growth impairment and skeletal alterations. The growth plate in long bones showed decreased chondrocyte proliferation rates and reduced height of terminal chondrocytes. Furthermore, we demonstrate that Jak1 is also involved in bone remodeling early in life. Jak1 animals have decreased bone and cortical volume, imbalanced bone remodeling, reduced MAP kinase signaling, and local inflammation. In conclusion, Jak1 plays a major role in bone health probably both, directly and systemically by regulating mineral homeostasis. Understanding the role of this signaling pathway will contribute to a better knowledge in bone growth and in mineral physiology, and to the development of selective Jak inhibitors as osteoprotective agents.
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http://dx.doi.org/10.1096/fj.202100587RDOI Listing
July 2021

Obituary: Vietla Satyanarayana Rao.

Chem Biol Interact 2021 Jun 8:109539. Epub 2021 Jun 8.

University of Fortaleza, Brazil.

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http://dx.doi.org/10.1016/j.cbi.2021.109539DOI Listing
June 2021