Localization of [F]fluorodeoxyglucose in mouse brain neurons with micro-autoradiography

This is the first study of micro-autoradiography (micro-ARG) for [¹⁸F]2-fluoro-2-deoxy- -glucose ([¹⁸F]FDG). The localization of [¹⁸F]FDG was demonstrated in dendrites of neuron and also in the myelinated axon in mouse normal brain in vivo. The nucleolus was relatively free of label. The counted silver grain numbers in autoradiogram were linearly correlated to the ¹⁸F radioactivities in the specimen. The micro-ARG using positron emitting ¹⁸F is a very time-saving technique with 4 hours exposure compared with the conventional method using ³H- or ¹⁴C-labeled tracers.     

Disseminated BCG infection resembling langerhans cell histiocytosis in an infant with severe combined immunodeficiency: a case report

We present a very rare congenital immunologic disease, severe combined immunodeficiency syndrome (SCID) in 6-months-old-boy with prolonged mucocutaneous candidiasis, severe anaemia, skin rash similar to the infiltrative eczema of Langerhans cell histiocytosis (LCH) and subcutaneous nodules with histiocytic infiltration. Laboratory findings show profound absence of humoral and cell-mediated immunity. Pathology specimens analysis of subcutaneous nodule revealed numerous S-100 protein and Cd1a negative histiocytes, occupied by BCG intracellular growth. Histopathology and immunohistochemistry confirmed the diagnosis of BCG dissemination. BCG vaccination in infants with SCID can lead to life threatening dissemination, resembling to the infiltrative eczema of LCH and may mislead the clinician.     

Genotoxicity of marine sediments in the fish hepatoma cell line PLHC-1 as assessed by the Comet assay

The main goal of this study was to test the usefulness of the Comet assay in the PLHC-1 hepatoma fish cell line as a tool for detecting the presence of genotoxic compounds in contaminated marine sediments. The system has been tested using both model chemicals (benzo[a]pyrene (B[a]P) and ethyl methanesulfonate (EMS)) and extracts of sediment samples obtained with solvent dichloromethane/methanol. For all of the analysed sediment extracts as well as for the model chemicals a concentration dependent genotoxic effect was observed. The sediment with the highest observed genotoxic potential was additionally extracted using various solvents in order to test which class of compounds, according to their polarity, is most responsible for the observed genotoxic effect. Non-polar solvents (cyclohexane and dichloromethane) yielded stronger genotoxic effect but the highest level of DNA damage was determined after exposure to sediment extract obtained with the solvent mixture dichloromethane/methanol which extracts a wide range of contaminants. Our results indicate that the PLHC-1 cell line is a suitable in vitro model in sediment genotoxicity assessment and encourage the use of fish cell lines as versatile tools in ecogenotoxicology.     

CYP1A induction potential and the concentration of priority pollutants in marine sediment samples -In vitro evaluation using the PLHC-1 fish hepatoma cell line

The use of in vitro biotests in combination with chemical determination of priority pollutants is considered a promising approach in environmental risk assessment. The main goal of this study was to evaluate the relationship between the CYP1A induction potential and the concentration of priority pollutants (PAHs, PCBs and heavy metals) in contaminated marine sediments. Six sediment samples characterized by different types of pollution were collected from the Bay of Kvarner, Croatia. CYP1A induction potency was determined in vitro by the measurement of ethoxyresorufin-O-deethylase (EROD) activity in PLHC-1 fish hepatoma cells. The results were compared to the potency of the model CYP1A inducer 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and expressed in 2,3,7,8-TCDD equivalents. All of the tested sediment samples were able to induce CYP1A activity in a dose-dependent manner. On a general scale, there was a good correlation between CYP1A induction and the concentration of priority pollutants in the tested samples. However, some samples, which had relatively low levels of priority pollutants, exhibited a strong CYP1A induction response. Therefore, apart from the confirmed usability and sensitivity of the EROD determination in the PLHC-1 cells as a suitable in vitro model in ecotoxicology, the results of this study indicate that the list of priority pollutants usually determined in the attempt to evaluate the risk of adverse effects to marine wildlife should be reconsidered.     

Characteristics of Work-related COVID-19 in Croatian Healthcare Workers: A Preliminary Report

Healthcare workers (HCWs) are considered to run a higher occupational risk of becoming infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and develop coronavirus disease (COVID-19) than the rest of the population. The aim of this study was to describe and analyse the characteristics of work-related COVID-19 in Croatian HCWs. Study participants were HCWs who contacted their occupational physician between 1 May 2020 and 12 November 2020 with a request for the registration of COVID-19 as an occupational disease. All participants filled out our online Occupational COVID-19 in Healthcare Workers Questionnaire. The study included 59 HCWs (median age 45.0, interquartile range 36.0–56.0 years). Most (78 %) were nurses or laboratory technicians, and almost all (94.9 %) worked in hospitals. Hierarchical cluster analysis revealed three clusters of COVID-19-related symptoms: 1) elevated body temperature with general weakness and fatigue, 2) diarrhoea, and 3) headache, muscle and joint pain, anosmia, ageusia, and respiratory symptoms (nasal symptoms, burning throat, cough, dyspnoea, tachypnoea). Almost half (44.6 %) reported comorbidities. Only those with chronic pulmonary conditions were more often hospitalised than those without respiratory disorders (57.1 % vs. 2.5 %, respectively; P=0.001). Our findings suggest that work-related COVID-19 among Croatian HCWs is most common in hospital nurses/laboratory technicians and takes a mild form, with symptoms clustering around three clinical phenotypes: general symptoms of acute infection, specific symptoms including neurological (anosmia, ageusia) and respiratory symptoms, and diarrhoea as a separate symptom. They also support evidence from other studies that persons with chronic pulmonary conditions are at higher risk for developing severe forms of COVID-19.Key words: comorbidity, hospitalisation, questionnaire, SARS-CoV-2, symptom clustering     

Effects of age and sex of host mice on growth and differentiation of teratocarcinoma OTT6050

The effect of age and sex of host mice 129/Sv on the growth rate and differentiation of teratocarcinoma OTT6050 was studied. Solid teratocarcinoma, inoculated on the back of mice, was measured by vernier calipers. Tumor volume was estimated from the product of three principal diameters. After drawing the calibration curve, the tumor growth curves of both male and female mice from 2 to 70 weeks old were plotted, compared, and analyzed by fitting the Gompertzian equation. On the juvenile hosts (2 and 3 w.o.), inoculated just after weaning, tumors grew fastest and consisted of necrosis and undifferentiated tissues. In the young adult mice (10 w.o.) tumor growth slowed down and tumors contained various kinds of well differentiated tissues around the necrotic area. Tumor growth was constant in the male from 10 to 70 w.o. But in the female, tumor growth slowed down with advancing age, from 10 to 70 w.o. In the 70 w.o. mice tumors contained large necrotic areas and less embryonal carcinoma cells and few differentiated tissues. There was no histological differences of tumor by host sex. Survival data showed that older mice could survive longer, with the exception of 70 w.o. mice. Teratocarcinoma growth curves showed the inhibiting effect of host aging on tumor growth rate, and the different tumor growth rate by host sex suggested the possible growth stimulation by estrogen.     

Pesticides and their binary combinations as P-glycoprotein inhibitors in NIH 3T3/MDR1 cells

The purpose of the present study was to assess do selected pesticides as well as their binary combinations act as inhibitors of P-glycoprotein (P-gp) activity of NIH 3T3 mouse fibroblasts stably transfected with human MDR1 gene (NIH 3T3/MDR1). As a result of P-gp inhibition, the increase of intracellular accumulation of a model P-gp substrate fluorescent calcein acetoxymethyl ester was measured. Pesticide and verapamil individual dose–response data were scaled and expressed as percent of maximum effect. Results showed that out of 14 pure pesticides tested, endosulfan, phosalone and propiconazole were nearly as potent as model inhibitor verapamil (EC₅₀ = 1.5 μM), while diazinon showed a lower potency of inhibiting P-gp transport activity (EC₅₀ = 58.4 μM). Concentrations of pesticides that produced the same inhibiting effect (isoboles) were combined binary. Results calculated using the isobole method revealed that diazinon caused synergistic effect in inhibiting P-gp transport activity in all combinations.     

Assessment of toxicological profiles of the municipal wastewater effluents using chemical analyses and bioassays

The hazardous chemical contamination of untreated wastewater and secondary effluent from the wastewater treatment plant (WWTP) of the city of Zagreb, Croatia was comprehensively characterized using large-volume solid-phase extraction (SPE) and silica gel fractionation, followed by a detailed analysis of the resulting extracts by a combination of chemical and bioassay methods. Over 100 individual contaminants or closely related-contaminant groups were identified by high-resolution gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF). Ecotoxicity profiling of the investigated samples, including cytotoxicity, chronic toxicity and EROD activity; inhibition of the multixenobiotic resistance (MXR), genotoxicicity and estrogenic potential, revealed the most significant contribution of toxic compounds to be present in polar fractions. Wastewater treatment using conventional activated sludge process reduced the initial toxicity of raw wastewater to various extents, ranging from 28% for algal toxicity to 73.2% for an estrogenic activity. The most efficient toxicity removal was observed for the polar compounds.     

Human pharmaceuticals modulate P-gp1 (ABCB1) transport activity in the fish cell line PLHC-1

The ubiquitous presence of pharmaceuticals in aquatic systems is a challenging problem as their potential chronic effects on aquatic organisms remain largely unknown. The ATP-binding cassette (ABC) transport proteins contributing to the multidrug/multixenobiotic resistance (MDR/MXR) phenomenon seem to have an important role in the elimination of xenobiotics in aquatic organisms. Modulation of their efflux activities by contaminants may lead to substantial increase in intracellular accumulation and toxic effects of other xenobiotics. The aim of our work was to analyse a series of pharmaceuticals for their potential to modulate the activity of xenobiotic efflux transporters from the ABCB and ABCC sub-family in the Poeciliopsis lucida hepatoma cell (PLHC-1) fish cell line (PLHC-1/wt) and a doxorubicin (DOX) resistant PLHC-1 subclone (PLHC-1/dox) characterized by an elevated expression of the P-glycoprotein (ABCB1). Cellular accumulation of the model fluorescent substrates calcein-AM and rhodamine123 were used to determine an inhibitory effect on P-gp1 and/or MRP-like efflux transporters. 18 out of 33 tested pharmaceuticals showed MXR inhibitory activity with IC50 values occurring in the lower micromolar to millimolar range. Further, cytotoxic effects of pharmaceuticals were evaluated in PLHC-1/dox cells. Co-exposure of resistant cells to model P-gp1 inhibitor cyclosporine A (CyA) resulted in up to five times increased cytotoxicity of pharmaceuticals. In addition, some pharmaceuticals lead to a marked increase in cytotoxicity of doxorubicin, a model P-gp1 substrate. The modulation of toxicity by MDR inhibitors indicates their role in influencing cellular toxicity. In conclusion, the results of our study revealed significant inhibitory effects of environmentally relevant pharmaceuticals on P-gp1 and MRP-like transporters in fish. Our findings correspond well with data from mammalian systems indicating that the specificity and roles of the related efflux transporters may be similar in fish. Furthermore, due to the presence of active and inducible ABC transport proteins, the PLHC-1 cells appear to be a reliable in vitro system for the investigation of MDR/MXR mechanisms in fish.