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The anisotropic nature of charge transport through organic materials requires high control over the self-assembly of the organic materials. This is particularly so for conductive polymers, where transport occurs mainly along the polymers' backbone. Herein, we demonstrate the use of self-assembled monolayers (SAMs) to influence the self-assembly of poly(3-adamantylmethylthiophene). We employ two different SAMs, which interact with either the adamantyl- or the thiophene-functionality, respectively, and acquire distinct topologies as compared to the unmodified Au(111) surface. We compare these results with unmodified glass and mica (muscovite) surfaces, which are typically employed in the field of optoelectronics. We prove the usefulness and applicability of epitaxial effects and adamantyl substituents for organic electronics. This presents a viable way toward improved electronic performance for the field as a whole., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The polyesters poly(lactic acid) (PLA) and poly(3-hydroxybutyrate) (PHB) used in various applications such as food packaging or 3D printing were depolymerized by biobased aliphatic alcohols-methanol and ethanol with the presence of para -toluenesulphonic acid ( p -TSA) as a catalyst at a temperature of 151 °C. It was found that the fastest depolymerization is reached using methanol as anucleophile for the reaction with PLA, resulting in the value of reaction rate constant ( k ) of 0.0425 min -1 and the yield of methyl lactate of 93.8% after 120 min. On the other hand, the value of constant k for the depolymerization of PHB in the presence of ethanol reached 0.0064 min -1 and the yield of ethyl 3-hydroxybutyrate was of 76.0% after 240 min. A kinetics study of depolymerization was performed via LC-MS analysis of alkyl esters of lactic acid and 3-hydroxybutanoic acid. The structure confirmation of the products was performed via FT-IR, MS, 1 H NMR, and 13 C NMR. Synthesized alkyl lactates and 3-hydroxybutyrates were modified into polymerizable molecules using methacrylic anhydride as a reactant and potassium 2-ethylhexanoate as a catalyst at a temperature of 80 °C. All alkyl esters were methacrylated for 24 h, guaranteeing the quantitative yield (which in all cases reached values equal to or of more than 98%). The methacrylation rate constants ( k ') were calculated to compare the reaction kinetics of each alkyl ester. It was found that lactates reach afaster rate of reaction than 3-hydroxybutyrates. The value of k ' for themethacrylated methyl lactate reached 0.0885 dm 3 /(mol·min). Opposite to this result, methacrylated ethyl 3-hydroxybutyrate's constant k ' was 0.0075 dm 3 /(mol·min). The reaction rate study was conducted by the GC-FID method and the structures were confirmed via FT-IR, MS, 1 H NMR, and 13 C NMR.

Objective: The aim of this study was to analyse epidemiological and clinical characteristics of invasive pneumococcal disease (IPD) in adults before and after the introduction of the general childhood conjugate pneumococcal vaccination programme in the Czech Republic., Material and Methods: The retrospective observational sentinel study included adults with IPD admitted to the Na Bulovce Hospital in Prague from 1/2000 through 12/2019. A case of IPD was defined as isolation of Streptococcus pneumoniae from a primarily sterile site., Results: A total of 304 IPD cases were diagnosed during the study period, with a male to female ratio of 1.49:1 and age median of 58 years (IQR 43-73). The most prevalent clinical forms were bacteraemic pneumonia (185 cases; 60.9%) and purulent meningitis (90; 29.6%). A total of 157/293 patients (53.6%) required intensive care, and the case fatality rate was 25.3% (n = 77). The serotype was determined in 292 (96.0%) isolates, the most prevalent being serotypes 3 (38; 12.5%), 4 (28; 9.2%), 7F (24; 7.9%), 8 (21; 6.9%), and 1 (18; 5.9%). Both clinical and epidemiological characteristics of IPD caused by the most prevalent serotypes differed considerably. Patients diagnosed with serotype 3 were older, more frequently required intensive care, and showed higher mortality. The proportion of IPD caused by non-PCV13 serotypes increased from 28.8% (19/66) in 2000-2005 to 54.8% (40/70) in 2015-2019 (p = 0.001)., Conclusion: The study demonstrated that invasive diseases caused by the most prevalent pneumococcal serotypes differ in their epidemiological and clinical characteristics and case fatality rate. During the study period, there was a significant increase in IPD caused by non-PCV 13 serotypes, limiting the effect of vaccination in adults.

Objectives: The aim of the study was to determine the prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae co-infections among patients with newly diagnosed syphilis., Methods: In patients with any stage of newly diagnosed syphilis swabs were performed from urethra, rectum, pharynx and cervix according to the gender and type of sexual intercourse. From these smears standard validated nucleic acid amplification tests (NAATs) for Chlamydia trachomatis and Neisseria gonorrhoeae infections were done., Results: From 548 (488 men, 60 women) screened patients co-infection was detected in 15.9% of the cases. The majority of the co-infections (86.2%) were asymptomatic. The overall prevalence of chlamydial infection was 11.1% and 8.8% for gonococcal infections. In men who have sex with men (MSM) the prevalence of co-infections was significantly higher (20.0%) than in heterosexual men and women (4.2%) (p < 0.001). In MSM patients the presence of co-infection was significantly associated with HIV infection (p < 0.001). Among MSM 9.6% of the tests detected infection in anorectal site, while prevalence in urethral (2.8%) and pharyngeal (2.4%) localization was significantly lower. In heterosexual patients prevalence was less than 2.0% in all anatomic sites., Conclusions: The implementation of screening tests in case of sexually transmitted infections in patients with newly diagnosed syphilis is an important part in the management of this disease. These results suggest that screening of asymptomatic heterosexual patients leads to detection of minimum co-infections, but in MSM (especially HIV positive) should always be performed at least in anorectal site, where asymptomatic co-infections are common.

Antiretroviral therapy represents an essential element in the approach to treatment and prevention of human immunodeficiency virus (HIV). It has changed the fatal disease to a manageable chronic condition and is the most effective prevention of its human-to-human transmission. Knowledge regarding biological characteristics of the virus, its behavior in a human host and our understanding of these phenomena have been extended by clinical experience, new clinical data and recent scientific progress. The development of new drugs becomes a modifier for the existing therapeutic strategy and preference. Certain points are more specific than in the previous guidelines. Definitions of certain clinical and laboratory conditions have been specified more accurately. The indications of specific antiretroviral agents and pitfalls of their use in lifelong antiretroviral treatment are also described more in detail. The document is a result of a general consensus among infectious disease specialists working with HIV patients in the Czech Republic. It should serve as a basic instrument for clinicians recommending treatment of HIV infection as well as a foundation for the society when dealing with both state authorities and health care payers.

Objective: During last years, a significant increase of HIV infection transmitted through sexual intercourse among young adults has been reported in the Czech Republic. The issue of prevention, where sexual education belongs to an important preventive tool, is much more topical than ever before. The level of knowledge and attitudes related to HIV/AIDS among adolescents has not been assessed so far. The aim of our study was to explore this field in a nationally representative sample., Methods: Information was obtained using an anonymous questionnaire that was filled in by 1,627 adolescents 13 to 15 years old selected from a representative sample of 25 elementary and grammar schools in the Czech Republic., Results: Based on the survey results, good knowledge regarding primary HIV/AIDS prevention was noted in the majority of respondents who however tended to stigmatize HIV positive people., Conclusion: The study has confirmed the importance of school as the main source of information (reported by 50.8% of respondents). The result of our study can serve as a starting point in assessment and comparison of the effect of various educational programmes., (Copyright© by the National Institute of Public Health, Prague 2018.)

Presented are general principles of care for HIV-infected persons following their admission to an AIDS care center, initiation of antiretroviral therapy and follow-up. Scientific research, drug development and new clinical data in recent years have led to a change in certain therapeutic perspectives and preferences for the treatment of HIV infection. Certain conditions are better specified, which affect the choice of antiretroviral regimens. Procedures and criteria for monitoring the effect of treatment and indication of post-exposure prophylaxis are specified. The development of this document was based on the latest updates of the most prominent international and European recommendations. It also reflects some of the new scientific information published in recent months. However, general recommendations cannot fully cover all the possible alternatives. They only state basic principles based on current clinical studies, clinical observation and practice. The present document should be the basic source of information for physicians involved in the treatment of patients with HIV infection and should provide a quick reference when selecting treatment regimens in terms of modern pharmacotherapy as well as information on the pitfalls of this treatment. Finally, it should be a support for negotiations between the professional society, state authorities and health care payers.This updated version of the guidelines follows the 2012 edition; once again, they are supplemented by a modified tabular overview.

Since the notification of the first case of lymphogranuloma venereum (LGV) in the Czech Republic in 2010, the numbers of LGV cases have steadily increased in the country. In 2015, 40 LGV cases were diagnosed, bringing the total for 2010-2015, to 88 cases. The profile of the most affected group, HIV-positive men who have sex with men with a previous sexually transmitted infection, matches that of those described in LGV outbreaks in western Europe.

We present the case of a 66-year-old female after renal transplant with severe course of herpes zoster (HZ). Although HZ represents a common infectious complication of transplant patients, its variable manifestation and ability to disseminate warrants serious consideration. Prompt diagnosis and treatment are essential in preventing further spread and disastrous complications.

Neoangiogenesis and inhibition of apoptosis are two factors considered as major leading causes of tumorigenesis. NO, synthesized by NOS, plays an important role in tumour growth, dissemination and vascularization. Caspase-3 is an executive enzyme of apoptosis. The presented research work has been focused on the comparative evaluation of localization of the angiogenic and proapoptotic cytokines expressed in tonsillar diseases. The immunohistochemical reaction of eNOS, iNOS and caspase-3 in tonsillar cancer (N = 17), chronic tonsillitis (N = 11) and clinically healthy tonsils (N = 8) was detected. High eNOS occurrence in endothelial cells of highly vascularized regions in tonsillar cancer, variable eNOS expression in the vessels of lamina propria in chronic tonsillitis and high expression in the cytoplasm of endothelial cells of small veins in healthy tonsillar tissue was ascertained. Increased iNOS expression was found in cancer tissue in comparison with the healthy tonsils. Nevertheless, the highest expression of iNOS was found in chronic tonsillitis. Higher expression of caspase-3 was discovered in germinal centres of lymphoid follicles of the chronic tonsillitis tissue. However, the positivity in the interfollicular zone and surface squamous epithelium was weak only. Merely isolated caspase-3-positive cells were found in tonsillar cancer. Very low expression of caspase-3 was detected in the lymphatic follicles of the healthy tonsils. Research results showed high expression of eNOS in the carcinomatous tissue. The eNOS expression in chronic tonsillitis confirms its role in regulating the lymphocyte circulation. Low expression of caspase-3 in malignant epithelial cells of tonsillar cancer shows decreased capability of apoptosis compared to chronic tonsillitis tissue, where apoptosis seems to be rather frequent and concentrated in the germinal centres of lymphatic follicles. The differences in localization of eNOS and caspase-3 expression between benign and malignant processes may be a promising tool for precise morphological distinction of chronic inflammation and tumours.

Objective: The aim of the presented study was to perform the immunohistochemical detection of endothelial (eNOS) and inducible (iNOS) isoform of nitric oxide synthase in the adenomatous and hyperplastic parathyroid gland in relation to the apoptotic process., Design and Setting: Tissue samples from 12 patients with parathyroid gland adenoma (PGA) and 10 patients with secondary parathyroid gland hyperplasia (PGH) were collected during surgery at the Department of Otorhinolaryngology and Head and Neck Surgery of The First Faculty of Medicine in Prague., Methods: Three-step immunoperoxidase reaction on acetone-fixed cryostat sections was performed using both polyclonal and monoclonal antibodies against eNOS and iNOS. The detection of apoptotic cells was done using antibody against cleaved caspase-3 as an apoptotic marker., Results: The immunoreactivity to eNOS antibody was observed in the endothelial lining of vessels in PGA, PGH and in the rim of normal parathyroid gland adjacent to PGA sample. Variable expression of eNOS was confirmed in arteries, arterioles, capillaries and veins in the glandular parenchyma as well as in the surrounding connective tissue. There was no iNOS immunoreactive cell detected in any examined sample. No apoptotic cells were detected., Main Result: Our findings confirm that eNOS is regularly expressed in the vasculature of PGA and PGH., Conclusion: eNOS observed in the vasculature of the enlarged parathyroid glands can serve as a factor that contributes to the viability of hypertrophic pathologic tissue. The lack of stimulating signals may be a reason for negative iNOS detection and negligible apoptotic rate.

Authors present 114 children and adolescents of the total 3865 patients that underwent surgery on the Department of Otorhinolaryngology and Head and Neck Surgery, 1st Faculty of Medicine, Charles University, Prague, Department of Otorhinolaryngology of IPVZ, Prague because of a thyroid disease in years 1991-2000. The male/female ratio in the group was 1:6.5, 16 (13.9%) males and 99 (86.1%) females. For non-malignant disease, the male/female ratio was 1:6.5 and for malignant disease, it was 1:5.4. Thyroid surgery was indicated for non-malignant disease in 82 (71.9%) cases--11 males and 71 females. Most frequently it was indicated because of Graves-Basedow and Hashimoto toxicosis--in 39 children (34.2%), in 5 children (4.4%) for toxic adenoma. Because of the polynodular goiter surgery was indicated in 13 cases (11.4%), in 22 cases (19.3%) for mononodular goiter. Three girls (2.6%) were recommended for surgery because of Hashimoto thyreoiditis and for mechanic syndrome in diffuse goiter one girl (0.9%). Malignant tumor was found in 32 children (28.1%)--5 males and 27 females. Most frequent histological type was papillary cancer--in 25 cases (21.9%). Follicular cancer was diagnosed in four cases (3.5%) and medullar cancer in three cases (2.6%). TNM classification in children and adults is summarized in Table 1. Surgery was carried out in two children with distant metastases (lung localization). In both children the pre-disease stage lasted more than 12 months. The first manifestation of the disease was a finding of enlarged and palpable nodes on the neck. The authors summarize indications for surgery of thyroid diseases in children and adolescents. A treatment of the thyroid gland is a teamwork. Indication for surgery is carried out by a pediatric endocrinologist in cooperation with a surgeon specialized in thyroid surgery. The possible identification of the recurrent laryngeal nerve by a surgery microscope is an unquestionable advance. Children and adults should be centralized into health-care centers capable not only of surgery, but also of endocrinology care. In children with a malignant disease there is a need for cooperation with a pediatric oncologist and a following oncological treatment on a nuclear medicine department. The authors summarize the information about today's thyroid surgery care possibilities for children and adolescents. They point out the differences in indications and the decision about extent of surgery in children and adolescents.

Introduction: HGF (Hepatocyte Growth Factor), TGFbeta1 (Transforming Growth Factor beta1) and IGF-I (Insulin Like Growth Factor I) are cytokines that are involved in the parathyroid tumors formation and growth. We tried to determine, if there are changes and relationships in the production of these cytokines by tumor cells of parathyroid tumors., Material and Methods: We determined concentrations of HGF, TGFbeta1 and IGF-I in serum from peripheral blood of 16 patients with parathyroid adenoma and of 8 patients with parathyroid secondary hyperplasia before and after parathyroidectomy. Results were compared with serum levels in healthy people., Results: Both preoperative and postoperative HGF serum levels in patients with parathyroid adenoma and secondary hyperplasia are significantly higher than in healthy people. Preoperative and postoperative serum levels of TGFbeta1 in parathyroid adenoma and postoperative TGFb1 serum levels in parathyroid secondary hyperplasia are higher, compared with those in the healthy population and in parathyroid secondary hyperplasia preoperatively. There are no significant differences of IGF-I serum levels among the all investigated groups of patients., Conclusions: Changes in the growth factors production by parathyroid tumor cells are reflected by their concentrations in peripheral blood. The elevation of HGF serum levels in patients with parathyroid adenoma and hyperplasia can be explained by very high HGF production by tumor cells. Nevertheless, there is no decrease of HGF serum levels after the parathyroidectomy. That may be the result of the extratumoral production of this cytokine. Also TGFbeta1 and IGF-I serum levels indicate high possibility of the extratumoral production of these cytokines. Higher postoperative IGF-I serum levels (but not significantly) in parathyroid secondary hyperplasia are in accordance with its bone production.

IGF-I, HGF, TGFbeta1, bFGF and VEGF are involved in the pathogenesis of thyroid gland tumors and their growth. We decided to find whether changes in the production of these cytokines by thyroid tumor cells are reflected by changes of their peripheral blood. Using ELISA kits, we measured the concentrations of growth factors in the peripheral blood serum in 28 patients with thyroid gland tumors (14 adenomas, 14 papillary carcinomas) and compared these concentrations with those in healthy people. We found significantly lower serum levels of IGF-I in patients with thyroid adenoma compared to the healthy population. Serum levels of HGF and bFGF were significantly higher in patients with thyroid adenoma and papillary carcinoma compared with those in healthy subjects. Serum concentrations of TGFbeta1 and VEGF were not significantly different in any groups of investigated subjects. Changes in the production of these cytokines by thyroid gland tumor cells are reflected in their peripheral blood levels, but these levels also depend on a number of other physiological and pathological processes in the organism. However, significant differences of HGF and bFGF serum levels can be explained by their very high production by thyroid tumor cells and by their strong effect on the follicular and endothelial cell proliferation.

Objective: Angiogenic growth factors bFGF and VEGF ensure vascularisation of the growing tumor tissue. We decided to investigate their peripheral serum concentrations in patients with thyroid gland adenoma and papillary carcinoma and with parathyroid adenoma. We wanted to find the possible serum marker of these tumor diseases., Methods: 28 patients with thyroid gland tumor (14x adenoma, 14x papillary carcinoma) and 12 patients with parathyroid gland adenoma. Growth factors serum levels were measured by ELISA method., Results: We found significantly higher serum levels of bFGF in both groups of patients with thyroid adenoma (4.93 +/- 3.42 ng/ml) and papillary carcinoma (5.69 +/- 5.58 ng/ml) compared to the healthy population (1.47 +/- 1.77 ng/ml). There were no significant differences of VEGF serum levels between all examined groups of patients (adenoma 213 +/- 197, papillary carcinoma 210 +/- 179, healthy 227 +/- 231 pg/ml). We found significantly higher serum levels of bFGF in patients with parathyroid gland adenoma (7.59 +/- 9.12 ng/ml) compared to those in healthy people (1.47 +/- 1.77 ng/ml)., Conclusions: Higher bFGF serum concentrations in patients with thyroid and parathyroid tumors are in accordance with their immunohistochemical tissue levels described in the literature. Not so in VEGF. bFGF may be a serum marker of thyroid and parathyroid neoplasms.

This study is the in vitro part of a long-term program to investigate the impact of air pollution on the health of a population in a polluted region of Northern Bohemia. In order to assess the possible health risks associated with a complex mixture of hundreds of organic compounds adsorbed to air particles, we used a biomarker-directed fractionation procedure to evaluate biological activities of different chemical compound classes. The extractable organic compounds from the air particles collected in both the polluted and the control districts during the summers and winters of 1993-1994 were investigated. The principal aim of this study was to compare the DNA binding activities of those compound classes using an in vitro acellular assay coupled with 32P-postlabeling and an embryotoxicity assay using Chick Embryotoxicity Screening Test (CHEST). In both assays, the highest activity was due to the neutral fractions from which the aromatic subfractions containing mainly polycyclic aromatic hydrocarbons (PAHs) and their methyl-derivates were the most active for both localities and seasons. A good correlation between the levels of DNA adduct formation using S9 metabolic activation and the ED50 for all different complex mixtures of organic compounds was observed (r=0.773, p<0.001). DNA adduct maps and high performance liquid chromatography (HPLC) profiles were similar for samples from both districts and seasons. The major DNA adducts resulting from the crude extracts were identical to those derived from aromatic fractions. The DNA adducts tentatively identified constituted about 50% of the total adducts formed by the crude extracts following S9-metabolic activation. Our results confirmed the similarities of the major ubiquitous emission sources of organic compounds in both districts. This is the first report in which the biological activities of complex mixtures in short-term assays with remarkably different endpoints such as DNA adduct formation and embryotoxicity have been compared., (Copyright 1999 Elsevier Science B.V.)

Rubropunctatin (1), monascorubrin (2), monascin (3) and ankaflavin (4) were purified from the mycelium of Monascus purpureus by flash chromatography on silica gel or reversed phase. Their embryotoxicity towards chicken embryos decreased in the order 2 > 1 > 3 > 4. The lower homologues 1 and 3 exhibited teratogenic effects on these organisms. Significant antibiotic activities against Bacillus subtilis and Candida pseudotropicalis were found with compounds 1 and 2. Immunosuppressive activity on mouse T-splenocytes was most pronounced with compounds 3 and 4. None of the compounds showed significant cytotoxic activity towards rat hepatocytes in vitro. Incubation of resting cells of M. purpureus with glycine afforded the dark-red compounds 5 and 6 where the pyran moiety of 1 and 2 changed into the N-substituted dihydropyridine moiety by replacement of the O-atom by the amino group of glycine. Compounds 5 and 6 were less biologically active than the major pigments 1-4.

Mycotoxins zearalenone and vomitoxin (4-deoxynivalenol) are often joint contaminants of grains infested by micromycetes of the genus Fusarium. Toxic effects of both mycotoxins on experimental organisms and farm animals are well known, but we have not found any literary reference to toxic effects of the combination zearalenone and vomitoxin. Embryotoxic effects of zearalenone, vomitoxin and combinations of various doses of zearalenone with constant addition of vomitoxin were studied in a three-day chick embryo. The objective of the study was to determine the coaction of vomitoxin on zearalenone embryotoxicity. Thermostat-incubated fertile eggs of White Leghorn hens were candled after three-day incubation, the shell above the embryo was removed, and within the embryotoxicity range zearalenone, vomitoxin and various doses of zearalenone with constant addition of 2 micrograms vomitoxin were applied to morphologically normal embryos. The groups of ten embryos were applied mycotoxins and their combinations in 10 microliters of their solutions to amnions using a special glass micropipette. Control group comprised twenty embryos which were applied 10 microliters of solvents used, 1% NaHCO3 and 10% ethanol. The eggs were covered with glass plates and their incubation was going on until the eighth day of their development. The embryos that died during incubation were discarded. On the eighth day of development, surviving embryos were taken out from the eggs and malformations of head, orofacial region, body wall, limbs and heart were determined microscopically. Tab. I shows total numbers of dead and malformed embryos after application of the particular doses of zearalenone, vomitoxin, their combinations and control solvents. The embryotoxicity range started at a dose of 5 to 20 micrograms per embryo. Zearalanone did not have any teratogenic effects on chick embryos. Applications of high doses of zearalenone (100 and 30 micrograms) instantly caused arrhythmia, atrio-ventricular dissociation or even heart stoppage. The beginning of the embryotoxicity range for vomitoxin was found to be within the narrow range of 1 to 3 micrograms per embryo. Among malformations, only a defect of the interventricular septum of the heart was found in 4% of the cases. The combined embryotoxic effects of zearalenone and vomitoxin were of additive, and mostly embryolethal nature. Among the malformations searched for, only 5% of the embryos exhibited a defect of the interventricular septum of the heart. Due to the good prediction fitness of chick embryo that has been proved by estimates of mycotoxin toxicity to mammals it is possible to suppose that toxic effects of the frequently occurring combinations of zearalenone and vomitoxin in fusarium-infected feeds will also be of additive nature for farm animals.

Three and four-day-old chick embryos were exposed to thalidomide as well as to its hydrolysis products before and after in vitro biotrasformation of these compounds with rat liver homogenate. Significant embryotoxic effects of 30 and 100 micrograms doses per embryo encountered only in the case when the products of alkaline hydrolysis of thalidomide were pretreated with rat liver homogenate.

Recent data from deep uranium mines in Czechoslovakia indicated that mines are exposed to other mutagenic factors in addition to radon daughter products. Mycotoxins were identified as a possible source of mutagens in these mines. Mycotoxins were examined in 38 samples from mines and in throat swabs taken from 116 miners and 78 controls. The following mycotoxins were identified from mines samples: aflatoxins B1 and G1, citrinin, citreoviridin, mycophenolic acid, and sterigmatocystin. Some mold strains isolated from mines and throat swabs were investigated for mutagenic activity by the SOS chromotest and Salmonella assay with strains TA100 and TA98. Mutagenicity was observed, especially with metabolic activation in vitro. These data suggest that mycotoxins produced by molds in uranium mines are a new genotoxic factor for uranium miners.

Recent data from deep uranium mines in Czechoslovakia indicated that in addition to radon daughter products, miners are also exposed to chemical mutagens. Mycotoxins were identified as a possible source of mutagenicity present in the mines. Various methods of biomonitoring were used to examine three groups of miners from different uranium mines. Cytogenetic analysis of peripheral lymphocytes, unscheduled DNA synthesis (UDS) in lymphocytes, and lipid peroxidation (LPO) in both plasma and lymphocytes were studied on 66 exposed miners and 56 controls. Throat swabs were taken from 116 miners and 78 controls. Significantly increased numbers of aberrant cells were found in all groups of miners, as well as decreased UDS values in lymphocytes and increased LPO plasma levels in comparison to controls. Molds were detected in throat swabs from 27% of miners, and 58% of these molds were embryotoxic. Only 5% of the control samples contained molds and none of them was embryotoxic. The following mycotoxins were isolated from miners' throat swab samples: rugulosin, sterigmatocystin, mycophenolic acid, brevianamid A, citreoviridin, citrinin, penicilic acid, and secalonic acid. These data suggest that mycotoxins are a genotoxic factor affecting uranium miners.

A crucial role of the site of administration in the sensitivity of the alternative system using chick embryo for testing embryotoxicity was demonstrated by morphological evaluation of the effects of T-2 toxin and secalonic acid D, and by incorporation of [14C]sodium acetate radioactivity. Secalonic acid D, administered to 2-, 3-, and 4-day-old embryos in doses higher than 1 microgram produced mostly malformations of the face (bilateral cleft beak, microphthalmia) while the teratogenic effects of T-2 toxin were being limited to the embryonic trunk of 2-day-old embryos (rumplessness) after administering doses higher than 0.001 microgram. In case of subgerminal and intraamniotic injections, the doses of both mycotoxins needed for producing embryotoxic effects comparable to those obtained with the more commonly used yolk sac injections appeared to be lower by one and two orders of magnitude, respectively. The results stress the need of using the shortest transport channel of test substances from the site of application to the target tissues of the embryo, when the maximum sensitivity and reproducibility of the test system are to be expected.

Embryotoxic effects of 25 mycotoxins were investigated in two-, three- and four-day chick embryos; the results were evaluated on the eighth day of development. The embryotoxicity ranged from 0.0001 to 0.1 microgram per embryo in T-2 toxin, aflatoxin B1, G1, B2 and M1, cytochalasin E, ochratoxin A and PR-toxin; from 0.1 to 1.0 microgram per embryo in sterigmatocystin, aflatoxin G2, vomitoxin (4deoxynivalenol), patulin, rubratoxin B, secalonic acid D, mycophenolic acid, and from 1.0 to 100 micrograms per embryo in penicillic acid, cyclopiazonic acid, tenuazonic acid, citrinine, brevianamide A, zearalenone, fusaric acid, griseofulvin, kojic acid and 8-methoxypsolaren. Acute cardiotoxic effects were observed in PR-toxin, patulin, rubratoxin B, penicillic acid, citrinine and zearalenone. Teratogenic effects with a spectrum of different embryonal malformations occurred in T-2 toxin, ochratoxin A, PR-toxin, patulin, secalonic acid D, mycophenolic acid and citrinine. The embryotoxic effects demonstrated in chick embryos correlated with the well-know literary data on mammals. Considering the different chemical composition and biological effects of mycotoxins, we suppose that the embryotoxicity test of chick embryos will also be suitable for testing other biologically active substances in the environment.

The cellulolytic activity of Pythium ultimum and P. oligandrum was investigated in vitro during the mycelium growth. It was found that under a constant temperature of 24 degrees C the cellulolytic activity was changed according to the pH of the medium. The optimum of cellulolytic activity in P. ultimum was recorded at neutral pH, whereas that in P. oligandrum in acid medium. The enzymatic production depended on the age of culture as well.

Over the years 1983 to 1984, eight strains of Penicillium oxalicum were isolated from feed mixtures for chickens; all of them produced on wheat secalonic acid D (1 to 22 mg X kg-1). As found out, toxic dose of secalonic acid D for two-day, three--day and four-day chicken embryos is 0.90, 2.80 and 3.80 micrograms, respectively. Teratogenic effects, microophthalmia and bilateral beak fissure was observed in the embryotoxicity range on all days of application.

Out of 67 milk samples analyzed in the spring 1980, nine samples contained 0.05 to 0.10 microgram . 1(-1) of M1 aflatoxin. Fifty samples analyzed in the spring 1982 contained no M1 aflatoxin. The toxicity of M1 aflatoxin determined in two-, three- and four-day chick embryo amounted to 0.10 microgram, the toxicity of B1 aflatoxin to 0.014 microgram per embryo. On the basis of M1 aflatoxin content in milk and its toxicity it can be presumed that with the current fodder base for dairy cows no toxic effect of M1 aflatoxin in milk and milk products is to be expected.

In 1979 to 1983, 148 strains of Penicillium cyclopium were isolated from wheat and from poultry feed mixtures; 11.5% of these strains produced cyclopiazonic acid at the rate of up to 500 mg per kg of wheat. Forty-seven percent of the 96 isolates of Aspergillus flavus and 56% of the nine isolates of Penicillium griseofulvum produced cyclopiazonic acid at the maximum rate of 80 and 10 mg per kg. The ED50 of cyclopiazonic acid for two, three and four days old chicken embryo was found to be 2.40, 4.70 and 2.70 micrograms, respectively. Teratogenic effects were observed only in the two days old embryos in which the caudal end of trunk was shortened at the frequency of 0.36 and microophthalmia occurred at the frequency of 0.33. The LD50 of cyclopiazonic acid in day-old cockerels was found to be 21.71 mg per kg of weight.

Parasitic relationships between Pythium oligandrum Drechsler and some phytopathogenic species of the Oomycetes class were investigated on agar plates. A high parasitic ability of Pythium oligandrum on Pythium ultimum Trow, P. debaryanum Hesse, and Aphanomyces laevis De By species was proved in this study of relationships among these fungi, commonly populating the rhizosphere of emerging sugar beet. P. oligandrum produces numerous thin haustorial threads, searching the hyphae of host species and enwrapping them during the parasitation. In a later parasitation stage the host organs were enwrapped by thicker hyphae of P. oligandrum as well. P. oligandrum grew through the colony of parasitized species mostly within 24 hours after inoculation and was able to destroy it entirely within 5--6 days. P. oligandrum produced numerous fructification organs in contradistinction to parasitized species. P. oligandrum oospores germinated abundantly when host species were present. Hyperparasitism of P. oligandrum was found both in cultivation with a single host and in common cultivation with all three host species simultaneously.

Pythium oligandrum Drechsler was found as a very weak pathogen of emerging sugar-beet by means of the inoculation of the sterilized soil. The hyperparasitic ability of Pythium oligandrum Drechsler to relative species, viz. Pythium ultimum Trow and Pythium debaryanum (Hesse) were proved in rhizosphere of emerging sugar-beet. The rhizosphere soil inoculation by P. ultimum resulted in the sugar-beet emergence about 3% while the sugar-beet emergence achieved 110% if P. ultimum and P. oligandrum were inoculated simultaneously. The sugar-beet emergence due to the dual inoculation of rhizosphere soil by P. ultimum and P. debaryanum was about 3%, whereas due to P. ultimum, P. debaryanum, and P. oligandrum 77%.

Twenty-seven samples of fodder wheat from the 1980 harvest, visibly attacked by mould, were analyzed for the content of zearalenone. Zearalenone was found to be present in ten samples and its content ranged from 50 to 1300 micrograms per kg. One of the five samples of pelleted feeds, taken at random, contained 14 mg zearalenone per kg. Fifty-three moulds of the genus Fusarium were isolated from the feeds. Among the 19 moulds of F. graminearum, 15 produced zearalenone; 11 moulds of F. culmorum produced zearalenone in all cases, and of the two moulds of F. tricinctum one produced zearalenone. Ten moulds of F. oxysporum, eight moulds of F. sporotrichioides and three molds of F. moniliforme did not produce any zearalenone. Under the described conditions the tested moulds produced 200 to 1200 mg of zearalenone per 1 kg.

Material milled and sampled in 1986 in one Prague flour mill included two flour batches contaminated with a toxicogenic strain of Penicillium islandicum Sopp. P. islandicum, cultivated under experimental conditions, yielded the total of eight grams of chloroform extract containing three grams of luteoskyrin from a kilogram of wheat. The effective dose of chloroform extract was 0.8 microgram (0.5-1.8) for a two-day old chicken embryo, 2.0 microgram (1.7-2.6) for a three-day old embryo and 2.8 micrograms (1.7-4.7) for a four-day old embryo. On all days of administration the chloroform extract had a strong teratogenous action. The most frequent malformations included microophthalmia and anophthalmia, cerebral hernia, bilaterally cleft beak, and reduction deformities of the extremities.

The toxinogenicity of 720 fungal isolates was evaluated using the Chisk Embryotoxicity Screening Test (CHEST, phase I). Three hundred and sixteen (43.9%) isolates produced some of the 23 identified mycotoxins, unidentified toxic metabolites were produced by 170 (23.6%), and 234 (32.5%) isolates showed no signs of toxinogenicity. The 24 h lasting chick embryo assay proved very suitable for detecting fungal products with general cytotoxic potential where it yielded results consistent with those obtained with cell cultures and higher organisms. Simplicity, rapidity, and modest laboratory equipment belong to the advantages of this reliable and non expensive screening procedure.

In the past 5 years we have observed 27 children at the age from 3 days to 8 years who died on the encephalic syndrome with fatty degeneration of the viscera (Reye). According to the morphological changes in the liver and to the clinical course, we have divided our cases into 3 groups. In the first group there were 20 children who died within 2-10 days after the first symptoms of the disease appeared. In their liver diffuse fatty degeneration was found. In the second group there were 3 children who died within 1-2 months after the acute onset of the disease. In their liver fibrosis with bile duct proliferation and steatosis were found. In the third group there were 4 children who died within 2-4 months after the first symptoms. Their liver showed cirrhosis. The bacteriological and virological investigations in all cases were negative, but in the most of them direct contacts with viral infections were proved. In the liver specimens of the children in all 3 groups the presence of aflatoxin B1 chromatographically and spectrophotometrically was found. The source of the intoxication in 5 cases was aflatoxin contaminated milk food. Our observations of 2 - 3 - days old newborns with the morphological changes similar to that of Reye's syndrome seems to support our hypothesis about the possibility of the intrauterine intoxication. We suggest that aflatoxin represents an important factor in the etiology of this syndrome and a high risk for human health.

In the experiment the goat was administered an amount of 450 mg aflatoxin B1. The milk taken during the experiment was lyophilized and aflatoxins B1 and M1 were isolated. After the death of the goat some tissues, blood and bile of the experimental animal were analyzed to find out the aflatoxin content.

Feeding the maize silage infected with the mold Penicillium roqueforti resulted in 112 dairy cows in the loss of appetite, stoppage of rumen activity and gut inflammation. The abortion of first-calvers in the seventh and eighth month was observed. The mold P. roqueforti produced on the sterile maize silage, at the temperature of 20 degrees C, up to 160 mg of PR-toxin per kg after 22 days of cultivation. The maximum production in the liquid medium was 900 mg of PR-toxin per litre, at the temperature of 13 degrees C after 50 days of cultivation. The isolated PR-toxin was identified spectrophotometrically and by the thin-layer chromatography after detection by 3-methyl-2-benzothiazoline-hydrochloride. The dose of 0.01 microgram PR-toxin was extremely toxic for 40-hr old chicken embryos.U

Contamination with microscopic fungi was studied in broiler complete feed mixtures in 1983-1984. The contamination levels ranged from 10(1) to 10(5) of fungus units per gram of feed (mostly around 10(3) units per gram). Sixty species of microscopic fungi of sixteen genera were isolated from the feeds. The genera Aspergillus and Penicillium occurred most frequently (97% of samples), followed by Mucor (93%), Cladosporium (79%), Rhizopus (52%) and Fusarium (41%). Of the 64 isolates of ten species of microscopic fungi, 42 (66%) were toxicogenic, and out of 49 such strains, 27 (55%) were toxic.

Embryos of White Leghorn Fowls incubated for 40 h were injected subgerminally with 19 mycotoxins dissolved in 30% ethanol to provide a range of doses. Embryonic death as well as the incidence of caudal-trunk abnormalities were determined after a further 24 h incubation. Of the substances tested, the maximum toxic effects were exerted by T-2 toxin and diacetoxyscirpenol which produced 100% embryonic mortality at doses as low as 0.01 microgram. 100 micrograms of griseofulvin, on the other hand, were needed to achieve the same effect. Abnormal development of the caudal trunk was observed after T-2 toxin and diacetoxyscirpenol (0.001 micrograms each) and griseofulvin (10 micrograms) administration. Comparison of these data with results published for both cell and tissue culture techniques and for classical rodent acute toxicity tests reveals a high predictive value for the Chick Embryotoxicity Screening Test (CHEST I), at least for mycotoxins.

The embryotoxic potential of ochratoxin A and citrinin was studied after administering, either subgerminally or intraamniotically, single mounting doses of the mycotoxins to chicken embryos on days 2, 3, and 4. The beginning of the embryotoxicity dose range was found to be between 0.01 to 0.05 microgram for ochratoxin A and 1 to 10 micrograms for citrinin. The maximum response to both mycotoxins occurred after administration on day 3. In addition to significant growth retardation of fetuses, exencephaly, microphthalmia, cleft beak, reduction deformities of the limbs, and abdominal wall and ventricular septal defects were encountered on day 8 of incubation. When 4 micrograms of citrinin was constantly added to ochratoxin A administered in the dose range of 0.03 to 0.5 microgram, a strictly additive effect was seen. It may be supposed that citrinin produced together with ochratoxin A in some strains of Penicillium viridicatum Westling does not potentiate the clear-cut embryotoxic action of the latter mycotoxin.

The activity of 20 mycotoxins was tested by the recently developed initiator tRNA acceptance assay for carcinogens. With the exception of citrinin, all compounds carcinogenic for rodents stimulated the charging of tRNA with L-methionine. In three out of four non-carcinogenic mycotoxins the test was negative. Five carcinogenic mycotoxins were negative in mutagenicity tests but positive in the acceptance assay indicating that also non-mutagenic carcinogens may be detected by the latter procedure.

In connection with investigations of an occurence of potential mycotoxin producing moulds in the foodstuffs of the Czechoslovak Socialistic Republic the authors have followed the occurence of A. ochraceus strains in them and the ability of isolated strains to produce ochratoxin A in vitro. From 14708g of different kinds of foodstuffs and from 6757 on surface sterilized cereal and maize grains of Central European origin A. ochraceus have been isolated only 27 times, from 492g of foodstuffs and 8430 on surface sterilized green coffee beans imported from the tropical and subtropical countries 917-times. 11 (36.6%) from 30 tested strains, isolated from imported foodstuffs and coffee beans were producers of ochratoxin A in vitro, not a single strain of 20 tested strains from foodstuffs of domestic origin didn't produce ochratoxin A. On the basis of the obtained results the authors come to the conclusion, that in the foodstuffs of Central European origin the ochratoxin A producing A. ochraceus strains don't play probably an active role.

The embryotoxicity of aflatoxins B1, B2, G1, G2 and M1 was investigated after administration to chick embryos on either Day 2, 3 or 4. Treatment resulted mainly in embryolethality and a rank order for embryotoxicity was established where B1 greater than G1 greater than M1 = B2 greater than G2. The sensitivity of embryos to aflatoxin administration decreased with their age. These results document the general cytotoxic character of aflatoxin action upon the embryonic morphogenetic systems, actions that apparently require neither specific metabolic activation nor any specific target.

Out of the 25 strains of the genus Fusarium isolated from wheat visibly infested by moulds, three strains of F. graminearum were found to produce vomitoxin and zearalenone; the respective amounts of these toxins per 1 kg of wheat were 70, 100 and 600 mg vomitoxin, and 600, 400 and 250 mg zearalenone. The production of vomitoxin showed a marked decrease when the cultures were re-inoculated. An analytic determination of vomitoxin in cereals was worked out by the method of high-pressure liquid chromatography with a limit sensitivity of 20 micrograms vomitoxin per kg and by the method of thin-layer chromatography with a limit sensitivity of 100 micrograms vomitoxin per kg. The embryotoxicity of vomitoxin measured in chick embryos incubated for 40 hours was in the order of 1 microgram per embryo.

The authors describe the finding and identification of ochratoxin A in fodder barley of Czechoslovak produce. The fungus Penicillium verrucosum var. verrucosum, which is an ample producer of ochratoxin A, was isolated from a sample of barley. The isolated fungus was cultivated on several substrates at different temperatures and the production of ochratoxin A was studied during cultivation. The authors believe that the ochratoxicoses of farm animals may also occur in Czechoslovakia and that it would be useful to study this mycotoxin in selected feeds.