COVID-19 is still placing a heavy health and financial burden worldwide. Impairment in patient screening and risk management plays a fundamental role on how governments and authorities are directing ...resources, planning reopening, as well as sanitary countermeasures, especially in regions where poverty is a major component in the equation. An efficient diagnostic method must be highly accurate, while having a cost-effective profile. We combined a machine learning-based algorithm with mass spectrometry to create an expeditious platform that discriminate COVID-19 in plasma samples within minutes, while also providing tools for risk assessment, to assist healthcare professionals in patient management and decision-making. A cross-sectional study enrolled 815 patients (442 COVID-19, 350 controls and 23 COVID-19 suspicious) from three Brazilian epicenters from April to July 2020. We were able to elect and identify 19 molecules related to the disease’s pathophysiology and several discriminating features to patient’s health-related outcomes. The method applied for COVID-19 diagnosis showed specificity >96% and sensitivity >83%, and specificity >80% and sensitivity >85% during risk assessment, both from blinded data. Our method introduced a new approach for COVID-19 screening, providing the indirect detection of infection through metabolites and contextualizing the findings with the disease’s pathophysiology. The pairwise analysis of biomarkers brought robustness to the model developed using machine learning algorithms, transforming this screening approach in a tool with great potential for real-world application.
MicroRNAs (miRNAs), a class of small non-coding regulatory RNAs, have been detected in a variety of organisms ranging from ancient unicellular eukaryotes to mammals. They have been associated with ...numerous molecular mechanisms involving developmental, physiological and pathological changes of cells and tissues. Despite the fact that miRNA-silencing mechanisms appear to be absent in some Apicomplexan species, an increasing number of studies have reported a role for miRNAs in host-parasite interactions. Host miRNA expression can change following parasite infection and the consequences can lead, for instance, to parasite clearance. In this context, the immune system signaling appears to have a crucial role.
Sciatic axotomy in 2-day-old rats (P2) causes lumbar motoneuron loss, which could be associated with nitric oxide (NO) production. NO may be produced by three isoforms of synthase (NOS): neuronal ...(nNOS), endothelial (eNOS) and inducible (iNOS). We investigated NOS expression and NO synthesis in the lumbar enlargement of rats after sciatic nerve transection at P2 and treatment with the antioxidant melatonin (sc; 1
mg/kg). At time points ranging from P2 to P7, expression of each isoform was assessed by RT-PCR and immunohistochemistry; catalytic rates of calcium-dependent (nNOS, eNOS) and independent (iNOS) NOS were measured by the conversion of
3H
l-arginine to
3H
l-citrulline. All NOS isoforms were expressed and active in unlesioned animals. nNOS and iNOS were detected in some small cells in the parenchyma. Only endothelial cells were positive for eNOS. No NOS isoform was detected in motoneurons. Axotomy did not change these immunohistochemical findings, nNOS and iNOS mRNA expression and calcium-independent activity at all survival times. However, sciatic nerve transection reduced eNOS mRNA levels at P7 and increased calcium-dependent activity at 1 and 6
h. Melatonin did not alter NOS expression. Despite having no action on NOS activity in unlesioned controls the neurohormone enhanced calcium-dependent activity at 1 and 72
h and reduced calcium-independent catalysis at 72
h in lesioned rats. These results suggest that NOS isoforms are constitutive in the neonatal lumbar enlargement and are not overexpressed after sciatic axotomy. Changes in NO synthesis induced by axotomy and melatonin administration in the current model are discussed considering some beneficial and deleterious effects that NO may have.
Peripheral axotomy in neonatal rats induces neuronal death. We studied the anti-apoptotic protein Bcl-2 and cell death promoter Bax in spinal cord of neonatal rats after sciatic transection and ...treatment with melatonin, a neuroprotective substance. Pups were unilaterally axotomized at P2 and received melatonin (1 mg/kg; sc) or vehicle 1 h prior to lesion, immediately after, at 1 h, 2 h and then once daily. Rats were sacrificed at 3 h, 6 h, 24 h, 72 h and 5 days postaxotomy. Intact animals were used as controls. Lumbar enlargement was processed for Nissl staining, immunohistochemistry and RT-PCR for Bax or Bcl-2 and TUNEL reaction. Motoneurons (MN) of lesioned (L) and normal (N) sides were counted, and MN survival ratio (MSR
=
L/N) was calculated. Bax and Bcl-2 showed cytoplasmic immunoreactivity (IR). Bax IR was noticeable in small cells but less evident in MN. In unlesioned pups, some Bax-positive small cells (B+) and TUNEL-positive nuclei (T+) were mainly seen in the dorsal horn. In lesioned animals given vehicle, Bax mRNA levels and numbers of B+ and T+ were increased in comparison with intact controls at 24 h postaxotomy. The basal IR for Bax in MN was not changed by axotomy. Bcl-2 IR was noted in all cells and, like Bcl-2 mRNA, was unaltered after lesion. Melatonin reduced MN loss at 24 h, 72 h and 5 days and T+ at 24 h after lesion but did not interfere with Bax or Bcl-2 expression. These results suggest that (1) sciatic transection at P2 increases Bax mRNA and the amount of B+ and T+ in the lumbar enlargement, (2) Bax IR in immature MN is not altered by axotomy and (3) melatonin protects MN and dorsal horn cells through a mechanism independent of Bax and Bcl-2.
Infection with Zika virus (ZIKV), a mosquito-borne flavivirus has been casually linked with increased congenital microcephaly in Brazil from 2015 through 2016. Sensitive and specific diagnosis of ...patients with Zika fever (ZIKF) remains critical for patient management. We developed a ZIKV NS5 qRT-PCR assay by combining primers described by Balm et al. and a new Taqman probe. The assay was evaluated and compared with another assay described by Lanciotti et al. (ZIKV 1107) using 51 blood and 42 urine samples from 54 suspected ZIKV patients. ZIKV NS5 performed better in terms of sensitivity with more samples detected as ZIKV-positive (n = 37) than ZIKV 1107 (n = 34) for urine, and ZIKV-positive (n = 29) than ZIKV 1107 (n = 26) for blood. Both assays displayed good overall agreement for urine (κappa = 0.770) and blood (κappa = 0.825) samples. Improved availability of validated diagnostic tests, such ZIKV NS5 qRT-PCR, will be critical to ensure adequate and accurate ZIKV diagnosis.
Recent Zika outbreaks in South America, accompanied by unexpectedly severe clinical complications have brought much interest in fast and reliable screening methods for ZIKV (Zika virus) ...identification. Reverse-transcriptase polymerase chain reaction (RT-PCR) is currently the method of choice to detect ZIKV in biological samples. This approach, nonetheless, demands a considerable amount of time and resources such as kits and reagents that, in endemic areas, may result in a substantial financial burden over affected individuals and health services veering away from RT-PCR analysis. This study presents a powerful combination of high-resolution mass spectrometry and a machine-learning prediction model for data analysis to assess the existence of ZIKV infection across a series of patients that bear similar symptomatic conditions, but not necessarily are infected with the disease. By using mass spectrometric data that are inputted with the developed decision-making algorithm, we were able to provide a set of features that work as a "fingerprint" for this specific pathophysiological condition, even after the acute phase of infection. Since both mass spectrometry and machine learning approaches are well-established and have largely utilized tools within their respective fields, this combination of methods emerges as a distinct alternative for clinical applications, providing a diagnostic screening-faster and more accurate-with improved cost-effectiveness when compared to existing technologies.
Orientador: Gonçalo Amarante Guimarães Pereira
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Previous issue date: 2005
Resumo: O polifenismo de castas é um fenômeno multifacetado, sendo mais evidente em diferenças na capacidade reprodutiva e na longevidade entre rainhas e operárias. No presente estudo, a abelha sem ferrão Melipona quadrifasciata anthidioides foi escolhida para a investigação de diferenças na expressão gênica entre rainhas e operárias recém nascidas. Este estudo foi focalizado em adultos recém nascidos pois esse estágio representa o ponto final do desenvolvimento embrionário e o ponto inicial para o desempenho de tarefas casta-específicas. Inicialmente, foi empregada a metodologia do ¿differential display reverse transcription (DDRT)-PCR¿ e podendo ser detectada a expressão diferenciada de 14 genes entre rainhas e operárias. As diferenças no perfil de expressão foram posteriormente analisadas através de duas bibliotecas subtrativas de cDNA: uma representando genes muito expressos ou induzidos em operárias quando em comparação com rainhas, e a outra representando genes mais expressos na casta rainha. Embora o número total de seqüências geradas não tenha permitido uma compreensão completa dos transcriptomas das castas, foi possível detectar em rainhas a predominância de genes envolvidos na regulação transcricional e no metabolismo, em relação à ampla diversidade de categorias funcionais das ESTs encontradas na casta operária. Um outro grupo representando seqüências de funções desconhecidas apresentou elevada similaridade a seqüências de Apis mellifera, podendo, portanto, conter genes candidatos para investigações em processos específicos das abelhas sociais ou do desenvolvimento de castas de maneira geral. Além disso, este estudo questionou se rainhas induzidas pelo tratamento com hormônio juvenil (HJ) durante a fase larval poderiam apresentar níveis de expressão gênica similares aos de uma rainha produzida de modo natural. Curiosamente, os dados preliminares sugerem que a rainha artificial não apresenta o mesmo transcriptoma de uma rainha natural, indicando que o HJ pode induzir a diferenciação, mas não em todos os aspectos
Abstract: Caste polyphenism is a multifaceted phenomenon, most evident in the marked differences in reproductive capacity and longevity between queens and workers. In the present study, the stingless bee Melipona quadrifasciata anthidioides was chosen to investigate differences in gene expression between newly emerged adult queens and workers. This study has focused on newly emerged adults since this stage represents the endpoint of post-embryonic development and the starting point for caste-specific task performance.Initially, the methodology of differential display reverse transcription (DDRT)-PCR was employed and the differential expression for 14 M. quadrifasciata genes could be detected between queens and workers. The differences in the expression profile of the castes were further analysed through two subtractive cDNA libraries: one representing the genes that are overexpressed in workers, when compared with queens and the other representing genes which are overexpressed in queens.Although the total number of sequence does not allow a comprehensive picture of the caste transcriptomes, there seems to exist a predominance of genes involved in transcriptional regulation and metabolism in the queen ESTs, versus a much broader spectrum of categories in the worker ESTs. Another group representing sequences with unknown function displayed significant matches only with the Apis database and, therefore, may contain candidates for further investigations on processes specific to social bees or caste development in general.In addition, this study addressed the question of whether queens induced by treatment with juvenile hormone (JH) during the larval phase display genes with similar expression levels as naturally produced queens. Remarkably, our preliminary data suggest that the artificial queen does not present the same transcriptome of a natural queen, indicating that JH may not induce all aspects of the differentiation process
Doutorado
Genetica Animal e Evolução
Doutor em Genetica e Biologia Molecular
Cerebral malaria (CM) is a multifactorial syndrome involving an exacerbated proinflammatory status, endothelial cell activation, coagulopathy, hypoxia, and accumulation of leukocytes and parasites in ...the brain microvasculature. Despite significant improvements in malaria control, 15% of mortality is still observed in CM cases, and 25% of survivors develop neurologic sequelae for life—even after appropriate antimalarial therapy. A treatment that ameliorates CM clinical signs, resulting in complete healing, is urgently needed. Previously, we showed a hyperbaric oxygen (HBO)‐protective effect against experimental CM. Here, we provide molecular evidence that HBO targets brain endothelial cells by decreasing their activation and inhibits parasite and leukocyte accumulation, thus improving cerebral microcirculatory blood flow. HBO treatment increased the expression of aryl hydrocarbon receptor over hypoxia‐inducible factor 1‐α (HIF‐1α), an oxygen‐sensitive cytosolic receptor, along with decreased indoleamine 2, 3‐dioxygenase 1 expression and kynurenine levels. Moreover, ablation of HIF‐1α expression in endothelial cells in mice conferred protection against CM and improved survival. We propose that HBO should be pursued as an adjunctive therapy in CM patients to prolong survival and diminish deleterious proinflammatory reaction. Furthermore, our data support the use of HBO in therapeutic strategies to improve outcomes of non‐CM disorders affecting the brain.—Bastos, M.F., Kayano, A. C. A. V., Silva‐Filho, J. L., Dos‐Santos, J. C. K., Judice, C., Blanco, Y. C., Shryock, N., Sercundes, M. K., Ortolan, L.S., Francelin, C., Leite, J.A., Oliveira, R., Elias, R. M., Camara, N. O. S., Lopes, S.C.P., Albrecht, L., Farias, A. S., Vicente, C. P., Werneck, C. C., Giorgio, S., Verinaud, L., Epiphanio, S., Marinho, C. R. F., Lalwani, P., Amino, R., Aliberti, J., Costa, F. T. M. Inhibition of hypoxia‐associated response and kynurenine production in response to hyperbaric oxygen as mechanisms involved in protection against experimental cerebral malaria. FASEB J. 32, 4470–4481 (2018). www.fasebj.org
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