Prolonged viral shedding and antibody persistence in patients with COVID-19

SARS-CoV-2 as a new global threat has affected global population for one year. Despite the great effort to eradicate this infection, there are still some challenges including different viral presentation, temporal immunity in infected individuals and variable data of viral shedding. We studied 255 COVID-19 suspected individuals to assess the viral shedding duration and also the antibody development against SARS-CoV-2 among the cases. Real Time RT-PCR assay was applied to determine the virus presence and SARS-CoV-2 antibodies were evaluated using SARS-CoV-2 IgM and IgG kits. 113 patients were confirmed for COVID-19 infection. The patients were followed until negative PCR achieved. The median viral shedding among studied population was obtained 34.16 (±17.65) days which was not significantly associated with age, sex and underlying diseases. Shiver and body pain were found in prolonged form of the infection and also patients who had gastrointestinal problems experienced longer viral shedding. Moreover, IgG was present in 84% of patients after 150 days. According to this data, the median viral shedding prolongation was 34.16 days which indicates that 14 days isolation might not be enough for population. In addition, IgG profiling indicated that it is persistent in a majority of patients for nearly 6 months which has brought some hopes in vaccine efficacy and application.     

In silico and in vitro comparative activity of novel experimental derivatives against Leishmania major and Leishmania infantum promastigotes

This in silico and in vitro comparative study was designed to evaluate the effectiveness of some biurets (K1 to K8) and glucantime against Leishmania major and Leishmania infantum promastigotes. Overall, eight experimental ligands and glucantime were docked using AutoDock 4.3 program into the active sites of Leishmania major and Leishmania infantum pteridine reductase 1, which were modeled using homology modeling programs. The colorimetric MTT assay was used to find L. major and L. infantum promastigotes viability at different concentrations of biuret derivatives in a concentration and time-dependent manner and the obtained results were expressed as 50% and 90% of inhibitory concentration (IC₅₀ and IC₉₀). In silico method showed that out of eight experimental ligands, four compounds were more active on pteridine reductase 1. K3 was the most active against L. major promastigotes with an IC₅₀ of 6.8 μM and an IC₉₀ of 40.2 μM, whereas for L. infantum promastigotes was K8 with IC₅₀ of 7.8 μM. The phenylethyl derivative (K7) showed less toxicity (IC₅₀s > 60 μM) in both Leishmania strains. Glucantime displayed less growth inhibition in concentration of about 20 μM. In silico and especially docking results in a recent study were in accordance with the in vitro activity of these compounds in presented study and compound K3, K2 and K8 showed reasonable levels of selectivity for the Leishmania pteridine reductase 1.     

High-frequency microsatellite instability and BRAF mutation (V600E) in unselected Serbian patients with colorectal cancer

Microsatellite instability (MSI) is a genetic consequence of a MisMatch Repair defect in colorectal cancer (CRC). We compared clinicopathohistological features with MSI status of CRC and evaluated prognostic significance of MSI status and BRAF mutation in the group of MSI-H tumors. 155 primary CRCs were excised surgically, 2006–2008. MSI analysis was carried out using a fluorescence-based pentaplex polymerase chain reaction technique. BRAF mutation (V600E) was analyzed by direct sequencing in MSI-H tumors. For all patients were evaluated: age, gender, localization, tumor cell type, tumor differentiation, mucin production, lymphocytic infiltration (TILs) and TNM stage. Patients’ disease-free survival (DFS) was compared according to MSI and BRAF status using Kaplan–Meier test. Of the 155 CRCs, 19 (12.3%) were MSI-H, and 136 (87.7%) were MSS/L. BRAF mutations were found in 4 of the MSI-H tumors. Patients with MSI-H CRC had lower recurrence rate (log rank test; P = 0.04) than MSS/L group. Patients with MSI-H tumor and BRAF mutation had worse DFS than MSI-H tumors without this mutation (log rank test; P = 0.01). Most of the clinicopathologic characteristics of MSI-H CRC in Serbian patients are similar to those reported in previous studies. Patients with MSI tumor phenotype had favourable prognosis, but in those with BRAF mutation higher recurrence rate was observed.     

Isolation of progenitor cells from GFP-transgenic pigs and transplantation to the retina of allorecipients

Work in rodents has demonstrated that progenitor transplantation can achieve limited photoreceptor replacement in the mammalian retina; however, replication of these findings on a clinically relevant scale requires a large animal model. To evaluate the ability of porcine retinal progenitor cells to survival as allografts and integrate into the host retinal architecture, we isolated donor cells from fetal green fluorescent protein (GFP)-transgenic pigs. Cultures were propagated from the brain, retina, and corneo-scleral limbus. GFP expression rapidly increased with time in culture, although lower in conjunction with photoreceptor markers and glial fibrillary acid protein (GFAP), thus suggesting downregulation of GFP during differentiation. Following transplantation, GFP expression allowed histological visualization of integrated cells and extension of fine processes to adjacent plexiform layers. GFP expression in subretinal grafts was high in cells expressing vimentin and lower in cells expressing photoreceptor markers, again consistent with possible downregulation during differentiation. Cells survived transplantation to the injured retina of allorecipients at all time points examined (up to 10 weeks) in the absence of exogenous immune suppression without indications of rejection. These findings demonstrate the feasibility of allogeneic progenitor transplantation in a large mammal and the utility of the pig in ocular regeneration studies.     

Inhibitor of PI3K/Akt Signaling Pathway Small Molecule Promotes Motor Neuron Differentiation of Human Endometrial Stem Cells Cultured on Electrospun Biocomposite Polycaprolactone/Collagen Scaffolds

Small molecules as useful chemical tools can affect cell differentiation and even change cell fate. It is demonstrated that LY294002, a small molecule inhibitor of phosphatidylinositol 3-kinase (PI3K)/Akt signal pathway, can inhibit proliferation and promote neuronal differentiation of mesenchymal stem cells (MSCs). The purpose of this study was to investigate the differentiation effect of Ly294002 small molecule on the human endometrial stem cells (hEnSCs) into motor neuron-like cells on polycaprolactone (PCL)/collagen scaffolds. hEnSCs were cultured in a neurogenic inductive medium containing 1 μM LY294002 on the surface of PCL/collagen electrospun fibrous scaffolds. Cell attachment and viability of cells on scaffolds were characterized by scanning electron microscope (SEM) and 3-(4,5-dimethylthiazoyl-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay. The expression of neuron-specific markers was assayed by real-time PCR and immunocytochemistry analysis after 15 days post induction. Results showed that attachment and differentiation of hEnSCs into motor neuron-like cells on the scaffolds with Ly294002 small molecule were higher than that of the cells on tissue culture plates as control group. In conclusion, PCL/collagen electrospun scaffolds with Ly294002 have potential for being used in neural tissue engineering because of its bioactive and three-dimensional structure which enhances viability and differentiation of hEnSCs into neurons through inhibition of the PI3K/Akt pathway. Thus, manipulation of this pathway by small molecules can enhance neural differentiation.     

Association between microRNA-21, microRNA-150, and micro-RNA-451 expression and clinical outcome of patients with acute lymphoblastic leukemia

Background

Acute lymphoblastic leukemia (ALL) occurs owing to the defective maturation, increased proliferation, and lack of differentiation of lymphoid cells. Evaluation of the expression levels of microRNAs (miRNAs) could help in the prognosis and improve the clinical outcome of ALL patients. Given the role of miR-21, miR-150, and miR-451 as oncogenes and tumor suppressors in lymphocytes, this study explored the relation between the expression levels of these miRNAs and the clinical outcomes of ALL patients.

Methods

cDNA synthesis and RT-PCR were performed for peripheral blood samples from 41 patients with ALL, as well as for U937 and Jurkat cell lines to examine the expression of miR-451, miR-150, and miR-21 after miRNA purification. We also performed an epidemiological analysis in which Mann–Whitney and Chi-square tests were used to investigate the relationship between the expression of miRNAs and other clinical and laboratory data. Binary logistic regression models were used to estimate the odds ratio in univariate and multivariate analyses for clinical outcomes.

Results

miR-21 and miR-150 expression was found to be decreased, while miR-451 expression showed no difference compared to the control group. There was a significant relationship between miR-451 expression and hemoglobin (Hb) levels, as well as between miR-150 expression and clinical outcomes of ALL patients.

Conclusion

Increased expression of miR-451 decreased the Hb levels; reduced expression of miR-150 was associated with increased relapse rate in patients. Age, increased WBC, and decreased Hb levels were associated with increased relapse rates in ALL patients. Therefore, miR-150 could be used as a biomarker to determine the clinical outcome of ALL patients.

     

A multi-spectroscopic and molecular docking approach to investigate the interaction of antiviral drug oseltamivir with ct-DNA

The possible interaction between the antiviral drug oseltamivir and calf thymus DNA at physiological pH was studied by spectrophotometry, competitive spectrofluorimetry, differential pulse voltammogram (DPV), circular dichroism spectroscopy (CD), viscosity measurements, salt effect, and computational studies. Intercalation of oseltamivir between the base pairs of DNA was shown by a sharp increase in specific viscosity of DNA and a decrease of the peak current and a positive shift in differential pulse voltammogram. Competitive fluorescence experiments were performed using neutral red (NR) as a probe for the intercalation binding mode. The studies showed that oseltamivir is able to release the NR.     

Experimental and computational studies on the effects of valganciclovir as an antiviral drug on calf thymus DNA

DNA-binding properties of an antiviral drug, valganciclovir (valcyte) was studied by using emission, absorption, circular dichroism, viscosity, differential pulse voltammetry, fluorescence techniques, and computational studies. The drug bound to calf thymus DNA (ct-DNA) in a groove-binding mode. The calculated binding constant of UV-vis, K_a, is comparable to groove-binding drugs. Competitive fluorimetric studies with Hoechst 33258 showed that valcyte could displace the DNA-bound Hoechst 33258. The drug could not displace intercalated methylene blue from DNA double helix. Furthermore, the induced detectable changes in the CD spectrum of ct-DNA as well as changes in its viscosity confirm the groove-binding mode. In addition, an integrated molecular docking was employed to further investigate the binding interactions between valcyte and calf thymus DNA.     

Characterization of a Mycobacterium tuberculosis Nanocompartment and Its Potential Cargo Proteins

Mycobacterium tuberculosis has evolved various mechanisms by which the bacterium can maintain homeostasis under numerous environmental assaults generated by the host immune response. M. tuberculosis harbors enzymes involved in the oxidative stress response that aid in survival during the production of reactive oxygen species in activated macrophages. Previous studies have shown that a dye-decolorizing peroxidase (DyP) is encapsulated by a bacterial nanocompartment, encapsulin (Enc), whereby packaged DyP interacts with Enc via a unique C-terminal extension. M. tuberculosis also harbors an encapsulin homolog (CFP-29, Mt-Enc), within an operon with M. tuberculosis DyP (Mt-DyP), which contains a C-terminal extension. Together these observations suggest that Mt-DyP interacts with Mt-Enc. Furthermore, it has been suggested that DyPs may function as either a heme-dependent peroxidase or a deferrochelatase. Like Mt-DyP, M. tuberculosis iron storage ferritin protein, Mt-BfrB, and an M. tuberculosis protein involved in folate biosynthesis, 7,8-dihydroneopterin aldolase (Mt-FolB), have C-terminal tails that could also interact with Mt-Enc. For the first time, we show by co-purification and electron microscopy that mycobacteria via Mt-Enc can encapsulate Mt-DyP, Mt-BfrB, and Mt-FolB. Functional studies of free or encapsulated proteins demonstrate that they retain their enzymatic activity within the Mt-Enc nanocompartment. Mt-DyP, Mt-FolB, and Mt-BfrB all have antioxidant properties, suggesting that if these proteins are encapsulated by Mt-Enc, then this nanocage may play a role in the M. tuberculosis oxidative stress response. This report provides initial structural and biochemical clues regarding the molecular mechanisms that utilize compartmentalization by which the mycobacterial cell may aid in detoxification of the local environment to ensure long term survival.     

Croatian children's views towards importance of health care information

The aim of research was to investigate: the need for health care information of Croatian adolescents aged from 13 to 18 years; the difference in evaluation of the frequency of receiving information between hospitalized and healthy children; if the hospitalized children expectations about the frequency of receiving health care information differed significantly from information they have actually received; whose information was most comprehensible to the hospitalized children (doctors, parents, other health care givers). The children were either hospitalized in the pediatrics departments or were high schools pupils (healthy children). The hospitalized children "Completely agreed" (92.7%) with the statement "When I am sick, I should receive information about my health" in comparison to the healthy children (85.1%). In comparison to healthy children, the hospitalized children assessed that doctors, other health care givers and parents should give them information more frequently. The experience of hospitalized children indicate that they received less information then they have actually excepted. The information received from doctors was mostly in correlation with the understanding of this information. We concluded that the children want to be informed about their health, especially hospitalized children. Health care professionals should offer understandable health care information according to the children's expectation.