Gene expression analyses reveal potential mechanism of inorganic arsenic-induced apoptosis in zebrafish.

Our previous study showed that sodium arsenite (200 mg/L) affected the nervous system and induced motor neuron development via the Sonic hedgehog pathway in zebrafish larvae. To gain more insight into the effects of arsenite on other signaling pathways, including apoptosis, we have performed quantitative polymerase chain reaction array-based gene expression analyses. The 96-well array plates contained primers for 84 genes representing 10 signaling pathways that regulate several biological functions, including apoptosis. We exposed eggs at 5 h postfertilization until the 72 h postfertilization larval stage to 200 mg/L sodium arsenite. In the Janus kinase/signal transducers and activators of transcription, nuclear factor κ-light-chain-enhancer of activated B cells, and Wingless/Int-1 signaling pathways, the expression of only one gene in each pathway was significantly altered. The expression of multiple genes was altered in the p53 and oxidative stress pathways. Sodium arsenite induced excessive apoptosis in the larvae. This compelled us to analyze specific genes in the p53 pathway, including cdkn1a, gadd45aa, and gadd45ba. Our data suggest that the p53 pathway is likely responsible for sodium arsenite-induced apoptosis. In addition, sodium arsenite significantly reduced global DNA methylation in the zebrafish larvae, which may indicate that epigenetic factors could be dysregulated after arsenic exposure. Together, these data elucidate potential mechanisms of arsenic toxicity that could improve understanding of arsenic's effects on human health.

Temporal dynamics of SARS-CoV-2 genome and detection of variants of concern in wastewater influent from two metropolitan areas in Arkansas.

Although SARS-CoV-2 can cause severe illness and death, a percentage of the infected population is asymptomatic. This, along with other factors, such as insufficient diagnostic testing and underreporting due to self-testing, contributes to the silent transmission of SARS-CoV-2 and highlights the importance of implementing additional surveillance tools. The fecal shedding of the virus from infected individuals enables its detection in community wastewater, and this has become a valuable public health tool worldwide as it allows the monitoring of the disease on a populational scale. Here, we monitored the presence of SARS-CoV-2 and its dynamic genomic changes in wastewater sampled from two metropolitan areas in Arkansas during major surges of COVID-19 cases and assessed how the viral titers in these samples related to the clinical case counts between late April 2020 and January 2022. The levels of SARS-CoV-2 RNA were quantified by reverse-transcription quantitative polymerase chain reaction (RT-qPCR) using a set of TaqMan assays targeting three different viral genes (encoding ORF1ab polyprotein, surface glycoprotein, and nucleocapsid phosphoprotein). An allele-specific RT-qPCR approach was used to screen the samples for SARS-CoV-2 mutations. The identity and genetic diversity of the virus were further investigated through amplicon-based RNA sequencing, and SARS-CoV-2 variants of concern were detected in wastewater samples throughout the duration of this study. Our data show how changes in the virus genome can affect the sensitivity of specific RT-qPCR assays used in COVID-19 testing with the surge of new variants. A significant association was observed between viral titers in wastewater and recorded number of COVID-19 cases in the areas studied, except when assays failed to detect targets due to the presence of particular variants. These findings support the use of wastewater surveillance as a reliable complementary tool for monitoring SARS-CoV-2 and its genetic variants at the community level.

Reproducibility challenges for biomarker detection with uncertain but informative experimental data.

Recent studies have revealed that circulating microRNAs are promising biomarkers for detecting toxicity or disease. Quantitative real-time polymerase chain reaction (qPCR) is often used to measure the levels of microRNAs. Besides complete and certain data, investigators inevitably have observed technically incomplete or uncertain qPCR data. Investigators usually set incomplete observations equal to the maximum quality number of qPCR cycles, apply the complete-observation method, or choose not to analyze targets with incomplete observations. Using biostatistical knowledge and published studies, we show that three commonly applied methods tend to cause biased inference and decrease reproducibility in biomarker detection. More efforts are needed to address the challenges to identify and detect reliable, novel circulating biomarkers in liquid biopsies.

Histopathological features of mucosa atrophy in atrophic body gastritis / Características histopatológicas da atrofia da mucosa na gastrite atrófica do corpo

ABSTRACT Introduction: Gastric mucosa atrophy became a major issue in gastric pathology because of its connection with risk lesions for gastric cancer. Although gastric atrophy is frequently associated with different diseases, it has been included in many studies simply as a generic pathological condition, and different causes of gastric atrophy are omitted. Objective: To study the histopathological features of gastric mucosa atrophy inH. pylori- negative patients with atrophic body gastritis (ABG). Material and methods: Consecutive cases of patients diagnosed with ABG, and presenting normal or just lightly inflamed antral mucosa, were studied. Patients with gastrointestinal cancer and those with history of prior gastrointestinal surgery were excluded. The presence of intestinal metaplasia and pseudoantral (PSA) metaplasia in atrophic body mucosa was assessed. Results: During the period of 2004-2006 a total of 7,309 patients underwent gastroesophageal endoscopy with biopsies of the gastric mucosa; 3,556 (48.6%) were males, and 3,713 (51.4%) females. Among them, 105 had the diagnosis of ABG confirmed, with 32 (30.5%) males, and 73 (69.5%) females (p < 0.001). Intestinal metaplasia and/or PSA metaplasia were identified in all patients. As isolated lesions, PSA metaplasia was more frequent than intestinal metaplasia, respectively 42 (40%) vs. four (3.8%) cases. In most patients (56.2%) both types of metaplasia occurred simultaneously, and no differences were observed among genders (p = 0.67). Conclusion: Gastric mucosa atrophy in ABG shows distinctive histopathological features which should be considered in studies on the relationship between gastric mucosa atrophy and gastric cancer.

RESUMO Introdução: A atrofia da mucosa gástrica tornou-se capítulo importante da patologia gástrica devido ao seu estreito relacionamento com as lesões de risco para o câncer gástrico. Embora a atrofia gástrica possa estar associada a diferentes doenças, ela tem sido abordada como um processo genérico, omitindo-se suas diferentes causas. Objetivo: Estudar as características histopatológicas da atrofia da mucosa gástrica em pacientes com gastrite atrófica do corpo (ABG). Material e métodos: Foram estudados casos consecutivos de pacientes com diagnóstico de ABG que apresentavam mucosa antral normal ou apenas alterações inflamatórias mínimas. Pacientes submetidos a cirurgia gastrointestinal prévia ou portadores de câncer gastrointestinal foram excluídos. Nas preparações histopatológicas, estudou-se a presença de glândulas que exibiam metaplasia intestinal e metaplasia pseudoantral (PSA). Resultados: No período 2004-2006, 7.309 pacientes foram submetidos à endoscopia esofagogástrica com biópsias, sendo 3.556 (48,6%) homens e 3.753 (51,4%) mulheres. Entre eles, 105 pacientes H. pylori negativos tiveram o diagnóstico de ABG confirmado, sendo 32 (30,5%) homens e 73 (69,5%) mulheres (p < 0,001). Glândulas com metaplasia intestinal e/ou metaplasia PSA foram identificadas em todos os pacientes. Isoladamente, a metaplasia PSA foi mais frequente que a metaplasia intestinal, respectivamente 42 (40%) vs. quatro (3,8%). Os dois tipos de metaplasia ocorreram simultaneamente na maioria (56,2%) dos pacientes, não se observando diferenças entre os gêneros (p = 0.67). Conclusão: A atrofia da mucosa gástrica na ABG mostra características histopatológicas próprias que devem ser consideradas nos estudos sobre o relacionamento da atrofia gástrica com o câncer gástrico.

Investigation on the 19S ATPase proteasome subunits (Rpt1-6) conservation and their differential gene expression in Schistosoma mansoni.

The ubiquitin-proteasome system is responsible for degradation of the majority of intracellular proteins in eukaryotic cells. The 26S proteasome proteolytic complex is composed of a 20S core particle responsible for protein degradation and the 19S lid which plays a role in the recognition of polyubiquitinated substrates. The 19S regulatory particle (Rps) is composed of ATPase (Rpt) and non-ATPase (Rpn) subunits. In this study, we analyzed the expression profile of 19S Rpt subunits in the larvae and adult stage of the Schistosoma mansoni life cycle. Conventional reverse transcriptase polymerase chain reaction (RT-PCR) revealed that the majority of the 19S Rpt subunits amplified at the expected molecular masses for various investigated stages. In addition, SmRpt1, SmRpt2, and SmRpt6 transcript levels were increased in 3 h-cultured schistosomula and reasonably maintained until 5 h in culture, as revealed by qRT-PCR. Phylogenetic analysis of 19S Rpt subunits showed high structural conservation in comparison to other Rpt orthologues. The mRNA expression profile of 19S Rpt subunits did not correlate with 26S proteasome proteolytic activity as judged by a (14)C-casein-degrading assay, in the early cultured schistosomula. Taken together, these results revealed a differential expression profile for 19S Rpt subunits whose transcript levels could not be directly associated to 26S proteasome activity.

The influence of iron, vitamin B(12), and folate levels on soluble transferrin receptor concentration in pregnant women.

BACKGROUND: Soluble transferrin receptor (sTfR) concentration is high in iron deficiency and in conditions of increased erythropoiesis. In developing countries like Brazil, pregnant women usually have concurrent iron, vitamin B(12), and folate deficiencies. This study investigated the relationship between serum sTfR concentration and iron, vitamin B(12), and folate status in pregnant women. METHODS: The concentration of the sTfR, hematocrit (Hct), hemoglobin (Hb), red blood cell (RBC) and white blood cell (WBC) counts, serum iron (SI), total iron-binding capacity (TIBC), transferrin saturation, serum ferritin, zinc protoporphyrin (ZPP), vitamin B(12), and serum and RBC folate were determined in 40 healthy pregnant women who delivered term babies. RESULTS: sTfR concentration was significantly higher when the women had iron deficiency (serum ferritin <10 microg/l, p<0.01), but there was no significant difference in sTfR concentration according to vitamin B(12), serum, and RBC folate concentrations. Women who had serum ferritin <10 microg/l also had lower vitamin B(12) values (p<0.01). There was no significant correlation between vitamin B(12) and serum folate with sTfR concentration. According to a regression analysis, sTfR concentration was associated with serum iron, serum ferritin, RBC count, and hemoglobin concentration. CONCLUSION: Iron was the only micronutrient that influenced the sTfR concentration. Vitamin B(12) and folate concentrations were probably not sufficiently low to have an impact on the sTfR concentration.