Experimental verification of a model describing the occupied volume by polymers in solution

A relation is proposed which yields the occupied volume by macromolecular chains in solution. The experimental verification of the model is carried out by a viscometric study of the ternary system polymer A/polymer B/solvent. More precisely the viscometric study permits the determination of the critical concentration c^** corresponding to the incipient overlap of spherical coils.     

Association of sleep duration and quality with immunological response after vaccination against severe acute respiratory syndrome coronavirus-2 infection

Growing evidence suggests that sleep could affect the immunological response after vaccination. The aim of this prospective study was to investigate possible associations between regular sleep disruption and immunity response after vaccination against coronavirus disease 2019 (COVID-19). In total, 592 healthcare workers, with no previous history of COVID-19, from eight major Greek hospitals were enrolled in this study. All subjects underwent two Pfizer–BioNTech messenger ribonucleic acid (mRNA) COVID-19 vaccine BNT162b2 inoculations with an interval of 21 days between the doses. Furthermore, a questionnaire was completed 2 days after each vaccination and clinical characteristics, demographics, sleep duration, and habits were recorded. Blood samples were collected and anti-spike immunoglobulin G antibodies were measured at 20 ± 1 days after the first dose and 21 ± 2 days after the second dose. A total of 544 subjects (30% males), with median (interquartile range [IQR]) age of 46 (38–54) years and body mass index of 24·84 (22.6–28.51) kg/m² were eligible for the study. The median (IQR) habitual duration of sleep was 6 (6–7) h/night. In all, 283 participants (52%) had a short daytime nap. In 214 (39.3%) participants the Pittsburgh Sleep Quality Index score was >5, with a higher percentage in women (74·3%, p < 0.05). Antibody levels were associated with age (r = −0.178, p < 0.001), poor sleep quality (r = −0.094, p < 0.05), insomnia (r = −0.098, p < 0.05), and nap frequency per week (r = −0.098, p < 0.05), but after adjusting for confounders, only insomnia, gender, and age were independent determinants of antibody levels. It is important to emphasise that insomnia is associated with lower antibody levels against COVID-19 after vaccination.     

The Complex Role of Lactic Acid Bacteria in Food Detoxification

Toxic ingredients in food can lead to serious food-related diseases. Such compounds are bacterial toxins (Shiga-toxin, listeriolysin, Botulinum toxin), mycotoxins (aflatoxin, ochratoxin, zearalenone, fumonisin), pesticides of different classes (organochlorine, organophosphate, synthetic pyrethroids), heavy metals, and natural antinutrients such as phytates, oxalates, and cyanide-generating glycosides. The generally regarded safe (GRAS) status and long history of lactic acid bacteria (LAB) as essential ingredients of fermented foods and probiotics make them a major biological tool against a great variety of food-related toxins. This state-of-the-art review aims to summarize and discuss the data revealing the involvement of LAB in the detoxification of foods from hazardous agents of microbial and chemical nature. It is focused on the specific properties that allow LAB to counteract toxins and destroy them, as well as on the mechanisms of microbial antagonism toward toxigenic producers. Toxins of microbial origin are either adsorbed or degraded, toxic chemicals are hydrolyzed and then used as a carbon source, while heavy metals are bound and accumulated. Based on these comprehensive data, the prospects for developing new combinations of probiotic starters for food detoxification are considered.     

Chronic biopsy proven post‐COVID myoendocarditis with SARS‐Cov‐2 persistence and high level of antiheart antibodies

PurposeTo study the clinical signs and mechanisms (viral and autoimmune) of myoendocarditis in the long‐term period after COronaVIrus Disease 2019 (COVID‐19).MethodsFourteen patients (nine male, 50.1 ± 10.2 y.o.) with biopsy proven post‐COVID myocarditis were observed. The diagnosis of COVID‐19 was confirmed by IgG seroconversion. The average time of admission after COVID‐19 was 5.5 [2; 10] months. An endomyocardial biopsy (EMB) of the right ventricle was obtained. The biopsy analysis included polymerase chain reaction diagnosis of viral infection, morphological, immunohistochemical (IHC) examination with antibodies to CD3, CD45, CD68, CD20, SARS‐Cov‐2 spike, and nucleocapsid antigens. Coronary atherosclerosis was ruled out in all patients over 40 years.ResultsThe new cardiac symptoms (congestive heart failure 3–4 New York Heart Association class with severe right ventricular involvement, various rhythm, and conduction disturbances) appeared 1–5 months following COVID‐19. Magnetic resonance imaging showed disseminated or focal subepicardial and intramyocardial late gadolinium enhancement, hyperemia, edema, and increased myocardial native T1 relaxation time. Antiheart antibodies levels were increased 3–4 times in 92.9% of patients. The mean left ventricular (LV) ejection fraction (EF) was 28% (24.5; 37.8). Active lymphocytic myocarditis was diagnosed in 12 patients, eosinophilic myocarditis in two patients. SARS‐Cov‐2 RNA was detected in 12 cases (85.7%), in association with parvovirus B19 DNA—in one. Three patients had also endocarditis (infective and nonbacterial, with parietal thrombosis). As a result of steroid and chronic heart failure therapy, the EF increased to 47% (37.5; 52.5).ConclusionsCOVID‐19 can lead to long‐term severe post‐COVID myoendocarditis, that is characterized by prolonged persistence of coronavirus in cardiomyocytes, endothelium, and macrophages (up to 18 months) in combination with high immune activity. Corticosteroids and anticoagulants should be considered as a treatment option of post‐COVID myoendocarditis.     

Modified CLSI Extended-Spectrum β-Lactamase (ESBL) Confirmatory Test for Phenotypic Detection of ESBLs among Enterobacteriaceae Producing Various β-Lactamases

The worldwide dissemination of Enterobacteriaceae producing AmpC β-lactamases and carbapenemases makes difficult the phenotypic detection of extended-spectrum β-lactamases (ESBLs), as they may be masked by these additional enzymes. A modification of the CLSI ESBL confirmatory test was developed and evaluated in a comparative study for its ability to successfully detect ESBLs among Enterobacteriaceae producing various carbapenemases (Klebsiella pneumoniae carbapenemase [KPC], VIM, NDM, and OXA-48) and plasmidic or derepressed AmpCs. The modified CLSI ESBL confirmatory test was performed with cefotaxime and ceftazidime disks with and without clavulanate, on which both boronic acid (BA) and EDTA were dispensed. A total of 162 genotypically confirmed ESBL-positive Enterobacteriaceae isolates (83 carbapenemase/ESBL producers, 25 AmpC/ESBL producers, and 54 ESBL-only producers) were examined. For comparison, 139 genotypically confirmed ESBL-negative Enterobacteriaceae isolates (94 of them possessed carbapenemases and 20 possessed AmpCs) were also tested. The standard CLSI ESBL confirmatory test was positive for 106 of the 162 ESBL producers (sensitivity, 65.4%) and showed false-positive results for 4 of the 139 non-ESBL producers (specificity, 97.1%). The modified CLSI ESBL confirmatory test detected 158 of 162 ESBL producers (sensitivity, 97.5%) and showed no false-positive results for non-ESBL producers (specificity, 100%). The findings of the study demonstrate that the modified CLSI ESBL confirmatory test using antibiotic disks containing both BA and EDTA accurately detects ESBLs in Enterobacteriaceae regardless of the coexistence of additional β-lactam resistance mechanisms.     

One-year recombinant growth hormone therapy does not improve hemoglobin state and morphology of erythrocytes in growth hormone deficient children

An increase in growth rates of children suffering from growth hormone deficiency (GHD) subjected to recombinant growth hormone treatment (rGHT) was shown to be accompanied by acceleration of metabolic processes that may stimulate oxygen consumption in various organs and tissues. Therefore, oxygen-transporting properties of RBC should undergo considerable changes during the rGHT. The aim of this study was to examine the effects of rGHT on erythrocyte shape and hemoglobin state in GHD children. The level of oxyhemoglobin (Oxy-Hb) in RBC was analyzed by Raman spectroscopy. The RBC count, mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV) and other parameters were calculated. The blood of eleven treatment-naive prepubertal children with GHD (aged 3–9, median 5.7 years) was examined and compared with control group (aged 5–7; median 6.0 years) at three time points: 0, 3 and 12 months of rGHT. Before rGHT, the MI in GHD children was higher (median 0.48 vs 0.14 p = 0.0018) and the RBC count was lower (median 4.20 vs 4.96 10¹² cells/L p = 0.0022) than in control group. After the treatment, cell count in GHD patients did not differ significantly from the control group, but Oxy-Hb level became higher (median 0.64 vs 0.41 p = 0.0075). During rGHT, MCV decreased (median 80.3 vs 83.2 μm³ p = 0.0231). Morphological and functional characteristics of erythrocytes in GHD children were shown to differ significantly from the healthy control group. A twelve-month rGHT partially improved some of the studied parameters but Oxy-Hb level and echinocyte count remained high.     

Peripheral levels of matrix metalloproteinase-9, interleukin-6, and C-reactive protein are elevated in patients with acute coronary syndromes: correlations with serum troponin I

BACKGROUND: Acute coronary syndromes (ACS) are characterized by activation of systemic and local inflammatory mediators. The interrelation between these soluble inflammatory markers and their association with markers of myocardial necrosis have not been extensively studied. HYPOTHESIS: The study was undertaken to evaluate the association of the systemic levels of matrix metalloproteinase-9 (MMP-9) and the tissue inhibitor of metalloproteinase-1 (TIMP-1), with C-reactive protein (CRP), interleukin-6 (IL-6), and serum troponin-I in patients admitted with ACS. METHODS: Analysis of serum concentrations of the above inflammatory markers was performed in 53 patients with unstable angina (UA) and in 15 with non-ST-segment elevation myocardial infarction (NSTEMI) within 48 h of admission, and 34 patients with stable coronary artery disease. RESULTS: Compared with patients with stable angina, those with ACS had elevated admission levels of MMP-9 (p = 0.04), CRP (p < 0.001), and IL-6 (p = 0.001), but not TIMP-1 (p = 0.55). Compared with patients with UA, those with NSTEMI also had higher levels of IL-6 (p < 0.001), CRP (p = 0.002), and MMP-9 (p = 0.05). CONCLUSIONS: In patients with ACS, the admission levels of inflammatory mediators, including MMP-9, CRP, and IL-6 are significantly elevated, specifically in association with serum troponin I. Systemic and local markers of inflammatory activity may be directly associated with myocardial injury.