Theoretical characterization of the reactions CH3XCH2O2 + NO (X = O,S)

The reactions of NO with the peroxy radicals CH₃SCH₂O₂ and CH₃OCH₂O₂ are investigated using ab initio and DFT electronic structure methods. The peroxy nitrite association adducts, CH₃XCH₂OONO, and the isomeric nitrate compounds, CH₃XCH₂ONO₂, X = O, S, are theoretically characterized and the heat of formation parameters are evaluated. The formation of the products, the oxy radical and nitrogen dioxide, CH₃XCH₂O + NO₂, take place in both cases, through the dissociation of the reaction intermediate, cis- CH₃XCH₂OONO, via low activation barriers located late in the exit valley. The negligible activation energies are in good agreement with the large rate coefficients observed experimentally.     

Prognostic value of ERCC1 in head and neck carcinoma treated with definitive or adjuvant radiotherapy

Purpose

To evaluate the prognostic significance of excision repair cross-complementation group 1 (ERCC1) expression in head and neck carcinoma patients treated with definitive radiotherapy (DR) or adjuvant radiotherapy (AR).

Methods

ERCC1 expression was assessed by immunohistochemical staining. A total of 48 patients were assessed.

Results

High ERCC1 expression was found in 23 patients (48 %). More ERCC1-positive tumours were detected in patients treated with DR than in patients treated with AR (73 vs. 36 %, respectively, p = 0.03). ERCC1 expression had no impact on overall survival neither in the whole cohort of patients (p = 0.16) nor in each particular treatment group (AR p = 0.98; DR p = 0.21).

Conclusions

ERCC1 expression had no predictive value in head and neck carcinoma patients treated with DR or AR. There might be difference in ERCC1 positivity that comes out of whether the assessment is done on biopsy or surgical specimens.     

Epidemiological characteristics,baseline clinical features,and outcomes of critically ill patients treated in a coronavirus disease 2019 tertiary center in continental Croatia

AimTo describe epidemiological characteristics and baseline clinical features, laboratory findings at intensive care unit (ICU) admission, and survival rates of critically ill coronavirus disease 2019 (COVID-19) patients treated at a tertiary institution specialized for COVID-19 patients.MethodsThis retrospective study recruited 692 patients (67.1% men). Baseline demographic data, major comorbidities, anthropometric measurements, clinical features, and laboratory findings at admission were compared between survivors and non-survivors.ResultsThe median age was 72 (64-78) years. The median body mass index was 29.1 kg/m². The most relevant comorbidities were diabetes mellitus (32.6%), arterial hypertension (71.2%), congestive heart failure (19.1%), chronic kidney disease (12.6%), and hematological disorders (10.3%). The median number of comorbidities was 3 and median Charlson Comorbidity Index (CCI) was 5. A total of 61.8% patients received high-flow nasal oxygen therapy (HFNO) and 80.5% received mechanical ventilation (MV). Median duration of HFNO was 3, and that of MV was 7 days. ICU mortality rate was 72.7%. Survivors had significantly lower age, number of comorbidities, CCI, sequential organ failure assessment score, serum ferritin, C-reactive protein, D-dimer, and procalcitonin, interleukin-6, lactate, white blood cell, and neutrophil counts. They also had higher lymphocyte counts, PaO₂/FiO₂ ratio, and glomerular filtration rate at admission. Length of ICU stay was 9 days. The median survival was 11 days for mechanically ventilated patients, and 24 days for patients who were not mechanically ventilated.ConclusionThe parameters that differentiate survivors from non-survivors are in agreement with published data. Further multivariate analyses are warranted to identify individual mortality risk factors.

The first case of coronavirus disease 2019 (COVID-19) in Croatia was confirmed on February 25, 2020 (1). Very soon, on March 11, the World Health Organization (WHO) declared a COVID-19 pandemic (2). As of February 25, 2021, there were more than 240 000 confirmed cases and 5489 deaths in Croatia.As a part of the national strategy against COVID-19 pandemic, the Ministry of Health and Civil Protection Headquarters decided that University Hospital Dubrava (UH) is to be repurposed into a Primary Respiratory Center for patients with confirmed COVID-19 infection. The intensive center of primary respiratory intensive center (PRIC-IC) is a subunit of UH Dubrava reserved for the treatment of patients with severe symptoms of COVID-19 who require mechanical ventilation, vasoactive hemodynamic support, continuous renal replacement therapy, and other aspects of intensive care (3). UH Dubrava became a COVID-19 tertiary center treating a third of all COVID-19 positive ICU patients in the country.As the pandemic was surging through Europe, the number of critically ill COVID-19 patients in UH Dubrava continued to grow, and ICU capacities needed expansion. During winter months, six intensive care units in PRIC were operating at the same time: Three were run by intensivists from UH Dubrava and three by intensivists from other hospitals in Zagreb, including University Hospital Center Zagreb, University Hospital Center Sestre Milosrdnice, University Hospital Sveti Duh, University Hospital Merkur, and Children''s Hospital Zagreb. The outcomes of critically ill patients treated in PRIC-IC therefore represent the work of intensivists from all hospitals in Zagreb.Although scientific knowledge of COVID-19 increases daily, limited information is available regarding early identification of individuals who are at risk of developing severe symptoms. Previous studies reported certain demographic features and clinical characteristics of patients who were likely to develop severe symptoms of COVID-19 and thus require mechanical ventilation (4-7). Studies worldwide reported high mortality rates for patients requiring mechanical ventilation, ranging from 40% to 97% (4,8-10). Unfortunately, some of these reports were preliminary and included patients without a completed ICU stay. The aim of our cohort retrospective study is to describe the demographic characteristic, clinical features, laboratory values, and outcomes among critically ill COVID-19 patients treated in PRIC-IC, UH Dubrava.     

Knowledge and attitudes of Croatian Dentists Regarding Antibiotic Prescription in Endodontics: A Cross-sectional Questionnaire-based Study

ObjectivesTo assess dentists'' level of knowledge and practice concerning antibiotic usage in endodontics using the European Society of Endodontology position statement as a reference.Materials and MethodsA cross-sectional study was conducted in the form of an electronic questionnaire consisting of 23 questions, including dentists’ demographic and professional characteristics, attitudes as well as experiences regarding antibiotics in endodontics. Data were evaluated by the Mann-Whitney test or the Kruskal Wallis 1-way ANOVA, α = 5%.ResultsThe overall mean self-reported knowledge of antibiotics usage in endodontics was 11.7±2.5 points, out of a maximum possible score of 23. The factors associated with a higher knowledge were: age (P≤0.001), clinical experience (P≤0.001), specialist training (P=0.008), and adherence to the guidance on the use of systemic antibiotics in endodontics (P=0.006). Dentists who specialized in endodontics (16.1±2.2) achieved higher levels of knowledge.ConclusionKnowledge on antibiotic usage in endodontics among dentists in Croatia is insufficient. There is a need for continuing education on the use of antibiotics among general dentists.Key words: Antibiotics, Dentists, Endodontics, Knowledge, Questionnaire     

Composite-induced toxicity in human gingival and pulp fibroblast cells

Objective. The most important requirement for a material to be used in medical applications is its biocompatibility. Dental composite materials come into direct contact with oral tissues, especially gingival and pulpal cells. This study was performed to evaluate possible DNA damage in cells of human origin exposed to dental composites in vitro using a cytogenetic assay. Materials and methods. Two composite resins (Vertise Flow, Kalore) were tested on human gingival and pulp fibroblasts using the acridine orange/ethidium bromide viability staining and alkaline comet assay. Cultures were treated with polymerized composites in two different concentrations (20 mg/ml, 40 mg/ml) for 14 days. Chi-square and Kruskall-Wallis non-parametric test were used for the statistical analysis (p < 0.05). Results. Significant cytotoxicity was observed for 40 mg/ml of Vertise Flow in both cultures, while Kalore (40 mg/ml) showed cytotoxic effect only on human pulp fibroblasts. A significant level of DNA damage was detected for both materials and concentrations, in both cell cultures. Conclusion. If the two cell cultures are compared, the pulp cells were more sensitive to the cyto/genotoxic effects of dental composites. Based on the results, one can conclude that the use of tested materials may cause cellular damage in gingival and pulp fibroblasts in vitro.     

Jugular phlebectasia in adult—an overlooked cause of cervical pain

Neurological Sciences -     

A novel interaction between FlnA and Syk regulates platelet ITAM-mediated receptor signaling and function

Filamin A (FlnA) cross-links actin filaments and connects the Von Willebrand factor receptor GPIb-IX-V to the underlying cytoskeleton in platelets. Because FlnA deficiency is embryonic lethal, mice lacking FlnA in platelets were generated by breeding FlnA^loxP/loxP females with GATA1-Cre males. FlnA^loxP/y GATA1-Cre males have a macrothrombocytopenia and increased tail bleeding times. FlnA-null platelets have decreased expression and altered surface distribution of GPIbα because they lack the normal cytoskeletal linkage of GPIbα to underlying actin filaments. This results in ∼70% less platelet coverage on collagen-coated surfaces at shear rates of 1,500/s, compared with wild-type platelets. Unexpectedly, however, immunoreceptor tyrosine-based activation motif (ITAM)- and ITAM-like–mediated signals are severely compromised in FlnA-null platelets. FlnA-null platelets fail to spread and have decreased α-granule secretion, integrin αIIbβ3 activation, and protein tyrosine phosphorylation, particularly that of the protein tyrosine kinase Syk and phospholipase C–γ2, in response to stimulation through the collagen receptor GPVI and the C-type lectin-like receptor 2. This signaling defect was traced to the loss of a novel FlnA–Syk interaction, as Syk binds to FlnA at immunoglobulin-like repeat 5. Our findings reveal that the interaction between FlnA and Syk regulates ITAM- and ITAM-like–containing receptor signaling and platelet function.The filamin family consists of three large dimeric proteins (filamin A [FlnA], FlnB, and FlnC) that cross-link actin filaments, tether membrane glycoproteins, and serve as scaffolds for signaling intermediates (Stossel et al., 2001; Zhou et al., 2010). The most abundant isoform of the family, FlnA, is encoded by the X chromosome in humans and mice (Feng and Walsh, 2004; Robertson, 2005). FlnA is composed of an N-terminal actin-binding domain followed by 24 Ig repeats, the C-terminal of which mediates their dimerization (Pudas et al., 2005). Human melanoma cells that lack FlnA have poor motility and continuous membrane blebbing (Cunningham et al., 1992; Flanagan et al., 2001). FLNA mutations have been associated with periventricular heterotopia, Ehlers-Danlos Syndrome, or familial cardiac valvular dystrophy (Fox et al., 1998; Robertson et al., 2003; Sheen et al., 2005; Kyndt et al., 2007; Unger et al., 2007). Loss of FlnA in mice results in embryonic lethality caused by pericardiac and visceral hemorrhage, severe cardiac structural defects, and aberrant vascular patterning (Feng et al., 2006; Hart et al., 2006).Platelets predominantly express FlnA (5 µM), although a small amount of FlnB is also expressed (<0.5 µM). Platelet FlnA has a critical structural role in attaching the Von Willebrand Factor (VWF) receptor complex GPIb-IX-V to the underlying actin cytoskeleton. aa 556–577 in the cytoplasmic tail of GPIbα constitutively interacts with FlnA Ig repeat 17 (Nakamura et al., 2006), and the loss of GPIbα in mice results in enlarged platelets, a phenotype which can be rescued by expression of a chimeric protein construct containing the cytoplasmic domain of human GPIbα (Ware et al., 2000; Kanaji et al., 2002). FlnA binding facilitates GPIbα surface expression in Chinese hamster ovary (CHO) cells (Feng et al., 2005), and the interaction between FlnA and GPIbα has been reported to influence VWF receptor function, although conflicting effects are found in the literature. CHO cells transfected with GPIbα mutants that lack the FlnA binding site have decreased VWF binding (Dong et al., 1997; Schade et al., 2003), VWF-induced cell aggregation (Mistry et al., 2000), and/or adhesion to a VWF matrix under high shear (Cranmer et al., 1999; Williamson et al., 2002; Cranmer et al., 2005). In contrast, another study has shown that FlnA binding to GPIbα negatively regulates VWF binding to CHO cells and CHO cell adhesion under both static and flow conditions (Englund et al., 2001). Platelets treated with cell-permeable peptide mimics of the FlnA binding site on GPIbα have decreased ability to activate their fibrinogen receptor, the integrin αIIbβ3, and change shape in response to VWF stimulation, suggesting that the interaction between FlnA and GPIbα positively modulates signaling events initiated by VWF in platelets (Feng et al., 2003; David et al., 2006).In this study the role of FlnA was probed in platelets. Mouse platelets lacking FlnA were generated by breeding FlnA^loxP/loxP females with GATA1-Cre males (Jasinski et al., 2001). Offspring FlnA^loxP/y GATA1-Cre males have <15% of normal blood platelet count, and their platelets lack FlnA. As expected, FlnA-null platelets are large, lack normal actin-GPIbα membrane attachments, and have an altered distribution of GPIbα on their surface. However, FlnA-null platelets surprisingly also have severe functional impairment in signaling responses downstream of the immunoreceptor tyrosine-based activation motif (ITAM)– and ITAM-like–mediated signal receptors GPVI and C-type lectin-like receptor 2 (CLEC-2). This specific signaling defect results from the loss of a novel and direct FlnA–Syk interaction mediated through Ig repeat 5 of FlnA. As a consequence, Syk is mistargeted in FlnA-null platelets, and ITAM signaling that normally leads to actin assembly, α-granule secretion, integrin αIIbβ3 activation, and protein tyrosine phosphorylation is interrupted. FlnA is, therefore, required for normal ITAM- and ITAM-like–based signaling responses.     

NCR1‐deficiency diminishes the generation of protective murine cytomegalovirus antibodies by limiting follicular helper T‐cell maturation

NKp46/NCR1 is an activating NK‐cell receptor implicated in the control of various viral and bacterial infections. Recent findings also suggest that it plays a role in shaping the adaptive immune response to pathogens. Using NCR1‐deficient (NCR1^gfp/gfp) mice, we provide evidence for the role of NCR1 in antibody response to mouse cytomegalovirus infection (MCMV). The absence of NCR1 resulted in impaired maturation, function and NK‐cell migration to regional lymph nodes. In addition, CD4⁺ T‐cell activation and follicular helper T‐cell (Tfh) generation were reduced, leading to inferior germinal center (GC) B‐cell maturation. As a consequence, NCR1^gfp/gfp mice produced lower amounts of MCMV‐specific antibodies upon infection, which correlated with lower number of virus‐specific antibody secreting cells in analyzed lymph nodes.