RENEB Inter-Laboratory Comparison 2021: The Dicentric Chromosome Assay.

After large-scale radiation accidents where many individuals are suspected to be exposed to ionizing radiation, biological and physical retrospective dosimetry assays are important tools to aid clinical decision making by categorizing individuals into unexposed/minimally, moderately or highly exposed groups. Quality-controlled inter-laboratory comparisons of simulated accident scenarios are regularly performed in the frame of the European legal association RENEB (Running the European Network of Biological and Physical retrospective Dosimetry) to optimize international networking and emergency readiness in case of large-scale radiation events. In total 33 laboratories from 22 countries around the world participated in the current RENEB inter-laboratory comparison 2021 for the dicentric chromosome assay. Blood was irradiated in vitro with X rays (240 kVp, 13 mA, ∼75 keV, 1 Gy/min) to simulate an acute, homogeneous whole-body exposure. Three blood samples (no. 1: 0 Gy, no. 2: 1.2 Gy, no. 3: 3.5 Gy) were sent to each participant and the task was to culture samples, to prepare slides and to assess radiation doses based on the observed dicentric yields from 50 manually or 150 semi-automatically scored metaphases (triage mode scoring). Approximately two-thirds of the participants applied calibration curves from irradiations with γ rays and about 1/3 from irradiations with X rays with varying energies. The categorization of the samples in clinically relevant groups corresponding to individuals that were unexposed/minimally (0-1 Gy), moderately (1-2 Gy) or highly exposed (>2 Gy) was successfully performed by all participants for sample no. 1 and no. 3 and by ≥74% for sample no. 2. However, while most participants estimated a dose of exactly 0 Gy for the sham-irradiated sample, the precise dose estimates of the samples irradiated with doses >0 Gy were systematically higher than the corresponding reference doses and showed a median deviation of 0.5 Gy (sample no. 2) and 0.95 Gy (sample no. 3) for manual scoring. By converting doses estimated based on γ-ray calibration curves to X-ray doses of a comparable mean photon energy as used in this exercise, the median deviation decreased to 0.27 Gy (sample no. 2) and 0.6 Gy (sample no. 3). The main aim of biological dosimetry in the case of a large-scale event is the categorization of individuals into clinically relevant groups, to aid clinical decision making. This task was successfully performed by all participants for the 0 Gy and 3.5 Gy samples and by 74% (manual scoring) and 80% (semiautomatic scoring) for the 1.2 Gy sample. Due to the accuracy of the dicentric chromosome assay and the high number of participating laboratories, a systematic shift of the dose estimates could be revealed. Differences in radiation quality (X ray vs. γ ray) between the test samples and the applied dose effect curves can partly explain the systematic shift. There might be several additional reasons for the observed bias (e.g., donor effects, transport, experimental conditions or the irradiation setup) and the analysis of these reasons provides great opportunities for future research. The participation of laboratories from countries around the world gave the opportunity to compare the results on an international level.

Schoolchildren thyroid volume in North Macedonia: data from a national survey in an iodine-sufficient country.

PURPOSE: North Macedonia is historically iodine deficient, but due to the longstanding and effective preventive measures, it has been considered iodine replete since 2003. The aim of the recent national survey was to re-evaluate iodine status and to measure thyroid volume (TVol) by ultrasound in schoolchildren as a representative of the general population. METHODS: A stratified probability proportionate to size cluster sampling was used to obtain a representative national sample of school children aged 7-10 years between the 28th of March and 4th of October 2016. Thyroid volume (TVol) was measured using ultrasonography in 1188 children. All TVol measurements were done by a single operator and their medians were compared with an international reference standard. RESULTS: Significant positive correlation was found between Tvol and age, height, weight, body surface area (BSA), body mass index (BMI) in both girls and boys (p < 0.001), but not between TVol and urinary ioidine concentration (UIC). The most important predictors for Tvol in all children were age, height, weight, BMI, and BSA ( all p < 0.001). In multivariate regression, independent predictors for TVol were only BSA (p < 0.001) and age (p = 0.004) after being adjusted for sex, BMI, and UIC (R2 = 0.291). The 97th percentile of Tvol in our survey was generally higher than in the reference study and goiter prevalence of 18.3% in boys and 15.6% in girls was found compared to the international standard. CONCLUSION: In our survey, Tvol of schoolchildren was larger than in the international reference study, although iodine nutritional status of the country has been considered sufficient for many years. In countries and regions with long and effective, well-documented iodine prophylaxis, the optimal way to have realistic normative TVol would be to create their TVol reference limits. Therefore, the provided data for TVol measured in our survey could be proposed as the national reference TVol for schoolchildren aged 7-10 years.

Properties of mechanochemically synthesized ZnS nanoparticles.

The bulk and surface properties of mechanochemically synthesized ZnS nanoparticles were studied. XRD, SEM, TEM (HRTEM), AFM, UV-VIS, low temperature nitrogen sorption as well as TPR characterization methods have been applied. Cubic ZnS nanocrystals (2-4 nm) with characteristic blue shift have been obtained by high-energy milling. There is an evidence of the nanocrystal aggregates formation in products of milling. The surface uniformity, homogeneity as well as enhanced uptake of hydrogen have been documented.

Toluene oxidation on titanium- and iron-modified MCM-41 materials.

Iron- and titanium-modified MCM-41 materials, prepared by direct synthesis at ambient temperature or wet impregnation technique, were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), temperature-programmed reduction (TPR), UV-vis diffuse reflectance, Mössbauer and FT-IR spectroscopies. Their catalytic behavior was studied in total oxidation of toluene. Materials with high surface area and well-ordered pore structure were obtained. The increase of the titanium content (up to 50%) in the bisubstituted, iron and titanium containing materials leads to partial structure collapse of the silica matrix. Finely dispersed anatase particles were also formed during the impregnation procedure. The catalytic activity of the bisubstituted materials was influenced by the method of their preparation, but higher catalytic stability could be achieved, compared to iron monosubstituted one. The nature of the catalytic active sites is discussed.

Arterial hypertension in patients with coronary artery disease treated with surgical myocardial revascularization.

OBJECTIVES: To evaluate the incidence and prognostic power of arterial hypertension in patients with coronary artery disease treated with surgical myocardial revascularisation, before and after the operation. BACKGROUND: Arterial hypertension is one of the leading modifiable risk factors in CAD patients who underwent CABG surgery with the major impact on clinical outcome in these patients. METHODS: 749 patients with mean age of 55 +/- 8 years, (639 male/119 female) were analyzed for their preoperative: demographic, clinical, left ventricular morphologic and functional and angiographic, perioperative: type of operation, type and number of applied conduits, in-hospital morbidity and mortality, and post-operative: demographic, clinical, left ventricular morphologic and functional and angiographic characteristics. Mean postoperative follow-up period was 5.97 +/- 4.27 years. RESULTS: Hypertension was found in 52.7% of patients before the operation, and it was the most frequent risk factor, without any differences between different age groups, but significantly more often in females (p = 0.0001), diabetics (p = 0.0001), and patients with preserved LV function (p = 0.011). Although significantly correlated with in-hospital morbidity (r = 0.085 and p = 0.023), HTA was not identified as independent predictor. The most predictable was the occurrence of early neurological complications. HTA was also found to be a predictor of long life prognosis in CABG patients, but not as independent prognostic factor. Significant reduction in incidence was found in post-CABG patients (30.1%), which is most likely a result of applied pharmacologic treatment. ACE-inhibitors, Ca-antagonists and B-blockers were applied in 39.44%, 30.1% and 33.6% of patients respectively, with significant positive correlations found for all of them as follows: r = 0.221, p = 0.0001, r = 0.316, p = 000.1 and r = 0.093, p = 0.031. CONCLUSION: Hypertension is the most powerful risk factor in CAD patients who undergo CABG surgery in our country, and a powerful prognostic factor of early and late clinical outcome. There is a trend toward decreasing the incidence of HTA in post-CABG patients, as a result of improved pharmacologic treatment after the operation (Tab. 5, Fig. 1, Ref. 13). Full Text (Free, PDF) www.bmj.sk.

Relationship between myocardial viability and improvement in left ventricular function and heart failure symptoms after coronary artery bypass surgery.

BACKGROUND: The evaluation of myocardial viability is an important preoperative parameter, predictive of improvement in regional and global left ventricular (LV) function after coronary artery bypass surgery (CABG). However, whether the presence of viability is also associated with relief of heart failure symptoms after revascularization is not always certain. The aims of the study were to define the relationship between extent of viable myocardium and improvement in LV function after CABG and to determine whether preoperative viability testing can predict improvement in heart failure symptoms. METHODS: Eighty-five consecutive patients with ischemic cardiomyopathy (mean LVEF 35%) undergoing surgical revascularization were studied with a Tc-99m sestamibi one-day rest/nitrate enhanced myocardial perfusion SPECT imaging (MPI) to assess viability. Regional and global function were measured before and 16 -/+ 6 months after revascularization. We have used the Bull's eye quantitative analysis of MPI scans and 17 segment model of LV function and perfusion evaluation. Heart failure symptoms were graded according to the New York Heart Association (NYHA) criteria, before and 16 -/+ 6 months after revascularization. RESULTS: The number of viable segments per patient was directly related to the improvement in LVEF after revascularization (r 0.79, P < 0.01). Patients with > 4 viable segments representing 24% of the left ventricle yielded the sensitivity of 83% and specificity of 79% respectively for predicting improvement in LVEF. Furthermore, the presence of four or more viable segments predicted improvement in heart failure symptoms after revascularization, with positive and negative predictive values of 79% and 74%, respectively. CONCLUSION: The presence of substantial viability (four or more viable segments, 24% of the left ventricle) on myocardial perfusion gated SPECT imaging in patients with ischemic heart failure before CABG surgery has significant correlation with the improvement in LVEF and heart failure symptoms postoperatively.

[Chronopharmacokinetics of the preparation biomet400 in patients with duodenal ulcer]. / Khronofarmakokinetika na preparata biomet400 pri bolni s duodenalna iazva.

Biomet400 is a selective H2-blocker produced by the firm "Pharmacia" of the Bulgarian Medical Academy. 11 patients were treated with the drug in a dose of 400 mg taken orally in the morning or in the evening. The pharmacokinetic analysis revealed a slower resorption of cimetidine in the patients who had taken the drug in the evening (Tmax = 2 h, resp. 1.67 h) and a lowered Cmax (1.96 micrograms/ml, resp. 2.79 micrograms/ml) in comparison with the patients who had taken the drug in the morning. In the patients who had taken the drug in the evening the apparent volume of distribution is statistically significantly higher (242 l, resp. 124 l by the morning administration) and a tendency toward a slower elimination than by the morning administration is found (t1/2 = 4.41 h, resp. 3.89 h). In the patients who had taken the drug in the morning the elimination is mainly by renal excretion (Clr = 405 ml/min, resp. 3.29 ml/min for the evening administration) while in the patients with evening administration the nonrenal clearance prevails (Clnr = 534 ml/min, resp. 339 ml/min). The results indicate the presence of chronopharmacokinetic differences in the cimetidine action and they can explain the better chronotherapeutic results of the treatment with biomet400 administered in the evening.

Liver insufficiency as a factor modifying the pharmacokinetic characteristic of the preparation nabumetone.

The effectiveness of the nonsteroidal anti-inflammatory agent nabumetone is related to the formation of an active metabolite: 6-methoxy-2-naphthylacetic acid. The plasma concentrations of nabumetone and its active metabolite, after administration of 1,000 mg single dose p.o., are followed at 0, 0.5, 1, 2, 4, 6, 8, 12, 24, 30 and 48 h in 6 patients with laboratory evidence for functional liver insufficiency caused by liver cirrhosis, confirmed by biopsy. In the patients with liver insufficiency the mean values of Cmax and AUC0-24 h for 6-methoxy-2-naphthylacetic acid were 26.75 +/- 8.45 mg/l and 623.64 +/- 161.8 mg X h/l respectively. They did not differ significantly from the values observed in healthy volunteers [v. Schrader et al. 1983]. The Tmax-value was prolonged to 8 h, compared to 4 h Tmax-value of the volunteers. There is a tendency towards a reduced bioavailability of 6-methoxy-2-naphthylacetic acid after nabumetone administration in patients with a more severely expressed pathologic impairment, compared to patients with slight morphologic changes of the liver parenchyma.

[Microbiological research on processed cheese]. / Mikrobiologichni prouchvaniia na topeni sirena.

Microbiologic studies were carried out with a total of 136 batches of 8 assortments of softened cheese to establish the amount and composition of the microbial content of this product. It was found that the total count of mesophilic organisms of 72.8 per cent of the investigated batches reached up to 200 000/g. The content of hygiene-indicative organisms (coliforms and enterococci) was limited: 97 per cent of batches had a coli titer of 1 and over 1. The content of enterococci in 54.4 per cent of the investigated was below 100/g, and in 4.4 per cent it was over 100 000/g. No Salmonella bacteria and plasmacoagulase positive staphylococci in 25, resp., 10 g of the product were found. Contamination with sporeforming aerobic and anaerobic organisms in 72.1, resp., 91.9 per cent reached up to 1000, resp., 100 per gram of the product. The amount of proteolytic bacteria in 61.8 per cent of the batches was up to 1000/g, and in 8 per cent only--up to 100 000/g. The content of yeasts and moulds in 58.8, resp. 83.1 per cent of the batches was below 100/g.

[Clinical observations on the therapeutic activity of the preparation mendiaxon in diseases of the biliary tract]. / Klinichni nabliudeniia vurkhu terapevtichnata aktivnost na preparata mendiakson pri zaboliavaniia na zhluchnite putishta.

The immediate effect of 400 mg mendiaxon was studied in 8 patients with various hepatobiliary diseases. The drug was administered via a duodenal tube in a duodenal drainage tubing according to a minute schedule during the phase of pure bile C secretion. An increased volume was found in all cases. The maximum choleresis exceeds the basal one from 3 to 8 times. The rate of bile flow, in the majority of the patients, was between 2 and 3.3. ml/min. The treatment was carried out on 25 patients in the course of 10 days with a daily dose of 1200 mg (400 mg three times). A good pain-killing effect was obtained. Adverse effects and allergic reactions were not observed. The results from our studies provided grounds to recommend mendiaxon use in the clinical practice.

[Biochemical and technological characteristics of the milk from Black-and White Dutch]. / Biokhimichna i tekhnologichna kharakteristika na mliakoto na kholandskoto cherno-shareno govedo

Studied were the composition and the technologic properties of the milk of Dutch Black pied cattle under this country's conditions. Milk samples were taken for analysis once in a month on a cow farm founded in 1964 with a total of 67 impregnated heifers and having at the time of investigation 88 cows, twelve of them remaining from the initial animals imported from Holland and the others being the offspring of the herd. It was established that the annual milk yield per forage cow, amounting to 44881 has the following index values; dry matter--12.63 +/- 0.48 per cent; butterfat per cent--4.07 +/- 0.2%; total protein--3.37 +/- 0.16 per cent; casein--2.56 +/- 0.16; slids-nonfat--8.54 +/- 0.24 per cent; calcium--0.126 +/- 0.002 per cent; phosphorus--0.079 +/- 0.003 per cent. The technologic properties of milk proved unsatisfactory: coagulation capacity--359 s; rheologic value--112.93 X 1.10(-5) V/cm3; and technologic coeficient--1.32. The data on the composition and the technologic properties of Dutch Black-pied cow's milk showed, on the whole, that most profitable is its processing into butter as against processing into cheese in which case the yields would be unsatisfactory.