TREC/KREC Levels and T and B Lymphocyte Subpopulations in COVID-19 Patients at Different Stages of the Disease

Background: T and B cell-mediated immunity can be assessed using T cell receptor excision circle (TREC) and Kappa-deleting recombination excision circle (KREC) analysis, respectively, and successful implementation of this method requires evaluation of the correlation between the TREC frequencies and T cell subsets as well as KREC levels and B lymphocyte subsets. The aim of the present study was to evaluate the correlation between the TREC/KREC concentrations and T/B lymphocyte subsets at different stages of COVID-19. Methods: We examined 33 patients in the acute stage of COVID-19 (including 8 patients with poor outcomes) and 33 COVID-19 survivors. TREC/KREC concentrations were measured using quantitative real-time PCR. T/B lymphocyte subsets were determined using flow cytometry. Results: Blood TREC and KREC levels were found to be significantly lower in the acute stage of COVID-19 compared to control values. Moreover, a zero blood TREC level was a predictor of a poor disease outcome. Reductions in CD3⁺CD4⁺CD45RO⁻CD62L⁻ and CD3⁺CD8⁺CD45RO⁻CD62L⁻ T cell counts (as well as in the main fractions of B1 and B2 B cells) indicated a favorable outcome in COVID-19 patients in the acute stage of the disease. Decreased CD3⁺CD4⁺CD45RO⁻CD62L⁺ and CD3⁺CD8⁺CD45RO⁻CD62L⁺ T cell frequencies and increased CD3⁺CD8⁺CD45RO⁻CD62L⁻ cell counts were found to indicate a poor outcome in patients with acute COVID-19. These patients were also found to have increased B1 cell counts while demonstrating no changes in B2 cell counts. The levels of effector T cell subsets an naïve B cells were normal in COVID-19 survivors. The most pronounced correlations between TREC/KREC levels and T/B cell subsets counts were observed in COVID-19 survivors: there were positive correlations with naïve T and B lymphocytes and negative correlations with central and effector memory T cell subsets. Conclusions: The assessment of correlations between TREC and T cell subsets as well as KREC levels and B cell subset counts in patients with acute COVID-19 and COVID-19 survivors has shown that blood concentrations of TREC and KREC are sensitive indicators of the stage of antigen-independent differentiation of adaptive immunity cells. The results of the TREC and KREC analysis correlated with the stages of COVID-19 and differed depending on the outcome of COVID-19.     

Visualization of Connexin 43-positive cells of glioma and the periglioma zone by means of intravenously injected monoclonal antibodies

The selectivity of monoclonal antibodies against the E2 extracellular fragment of connexin 43 (Cx43) for a glioma focus was studied in in vivo experiments on animals with intracranial C6 glioma. Antibodies labeled with two alternative labels, the radioisotope (125)I and the fluorophore Alexa 660, were intravenously injected to rats with 18-day gliomas. Seventy-two hours after injection, (125)I-labeled antibodies accumulated in the hemisphere where the glioma was located to a concentration of 0.27?±?0.01% of the injected dose per gram of wet weight, which exceeded their accumulation in the liver, spleen, and other organs. Fluorescent-labeled antibodies against the Cx43 fragment E2 specifically visualized cells in the peritumoral astroglial bank (a zone of active invasion of glioma cells). Double immunofluorescent visualization using antibodies against the Cx43 fragment E2 and glial fibrillar acidic protein (GFAP) showed that only a small proportion of the cells that bound the antibodies injected into the blood circulation were reactive astrocytes, whereas most of these cells were GFAP-negative and morphologically corresponded to astroblasts. These results suggest that antibodies against the extracellular Cx43 fragment E2 can be used for targeted transport of diagnostic and therapeutic drugs to the peritumoral invasion zone of high-grade gliomas.     

Migraine is comorbid with multiple sclerosis and associated with a more symptomatic MS course

The objectives of this study were: (1) to assess relative frequency of migraine in multiple sclerosis (MS) patients using the validated self-administered diagnostic questionnaire, and to compare the migraine rates in MS outpatients to age- and gender-matched historical population controls; (2) to compare clinical and radiographic characteristics in MS patients with migraine and headache-free MS patients. We conducted a cross-sectional study to assess the demographic profiles, headache features and clinical characteristics of MS patients attending a MS clinic using a questionnaire based on the American Migraine Prevalence and Prevention (AMPP) study. We compared the relative frequency of migraine in MS clinic patients and AMPP cohort. We also compared clinical and radiographic features in MS patients with migraine to an MS control group without headache. Among 204 MS patients, the relative frequency of migraine was threefold higher than in population controls both for women [55.7 vs. 17.1%; prevalence ratio (PR) = 3.26, p < 0.001] and men (18.4 vs. 5.6%; PR = 3.29, p < 0.001). In a series of logistic regression models that controlled for age, gender, disease duration, β-interferon use, and depression, migraine in MS patients was significantly associated (p < 0.01) with trigeminal and occipital neuralgia, facial pain, Lhermitte’s sign, temporomandibular joint pain, non-headache pain and a past history of depression. Migraine status was not significantly associated with disability on patient-derived disability steps scale or T2 lesion burden on brain MRI. Migraine is three-times more common in MS clinic patients than in general population. MS–migraine group was more symptomatic than the MS–no headache group.     

Characterisation of developmentally hypomineralised human enamel

Objectives

To investigate and clarify physical and chemical properties of enamel affected by molar incisor hypomineralisation (MIH).

Methods

A series of in vitro studies were performed on extracted molars affected by MIH and sound teeth for controls. Tooth sections underwent Vickers microhardness testing before lapping and subsequent transverse microradiographic analysis and examination under polarised light microscopy. Carbonate content was determined by CO₂ release from acid digestion. Unprepared and fractured surfaces were examined under scanning electron microscopy.

Results

MIH-affected molars demonstrated a severe degree of hypomineralisation with an average mineral content of only 58.8% vol% mineral. Vickers microhardness was significantly reduced in MIH compared with controls (1.8 ± 1.1 v 4.4 ± 1.0 GPa, p < 0.05) and polarised light microscopy revealed the bulk of MIH lesions had a porosity of ≤5% but also substantial areas of ≥10% and smaller areas exceeding 25% porosity. A surface layer was frequently observed on both intact and broken-down lesions and cervical regions of MIH teeth were typically spared. Carbonate content of MIH enamel was higher than control samples (6.6 ± 2.1 v 4.4 ± 1.1 wt%, p < 0.05). Scanning electron microscopy showed that both the enamel rod and surface ultrastructure were defective. Clinical characteristics did not consistently correlate with all properties.

Conclusions

The properties of MIH-affected enamel significantly differ from those of normal enamel and were highly variable, however some common characteristics were observed. Implications for aetiology and clinical management are discussed.     

Recombinant yeast screen for new inhibitors of human acetyl-CoA carboxylase 2 identifies potential drugs to treat obesity

Acetyl-CoA carboxylase (ACC) is a key enzyme of fatty acid metabolism with multiple isozymes often expressed in different eukaryotic cellular compartments. ACC-made malonyl-CoA serves as a precursor for fatty acids; it also regulates fatty acid oxidation and feeding behavior in animals. ACC provides an important target for new drugs to treat human diseases. We have developed an inexpensive nonradioactive high-throughput screening system to identify new ACC inhibitors. The screen uses yeast gene-replacement strains depending for growth on cloned human ACC1 and ACC2. In “proof of concept” experiments, growth of such strains was inhibited by compounds known to target human ACCs. The screen is sensitive and robust. Medium-size chemical libraries yielded new specific inhibitors of human ACC2. The target of the best of these inhibitors was confirmed with in vitro enzymatic assays. This compound is a new drug chemotype inhibiting human ACC2 with 2.8 μM IC₅₀ and having no effect on human ACC1 at 100 μM.     

Smoking and risk of glioma: a meta-analysis

Objective  

Although causal relationships between smoking and cancer risk have been established for many sites, most studies of brain cancer have not supported an association. However, two recent cohort studies showed increased risks of glioma among smokers. We quantified the association between smoking and glioma through a meta-analysis of the literature.