Sexual dimorphism in subterranean amphipod crustaceans covaries with subterranean habitat type.

Sexual dimorphism can evolve in response to sex-specific selection pressures that vary across habitats. We studied sexual differences in subterranean amphipods Niphargus living in shallow subterranean habitats (close to the surface), cave streams (intermediate), and cave lakes (deepest and most isolated). These three habitats differ because at greater depths there is lower food availability, reduced predation, and weaker seasonality. Additionally, species near the surface have a near-even adult sex ratio (ASR), whereas species from cave lakes have a female-biased ASR. We hypothesized (a) a decrease in sexual dimorphism from shallow subterranean habitats to cave lake species because of weaker sexual selection derived from changes in the ASR and (b) an increase in female body size in cave lakes because of stronger fecundity selection on account of oligotrophy, reduced predation, and weaker seasonality. We measured body size and two sexually dimorphic abdominal appendages for all 31 species and several behaviours related to male competition (activity, risk-taking, exploration) for 12 species. Species with an equal ASR that live close to the surface exhibited sexual dimorphism in all three morphological traits, but not in behaviour. The body size of females increased from the surface to cave lakes, but no such trend was observed in males. In cave lake species, males and females differed neither morphologically nor behaviourally. Our results are consistent with the possibility that sexual and fecundity selection covary across the three habitats, which indirectly and directly, respectively, shape the degree of sexual dimorphism in Niphargus species.

Parallel morphological evolution and habitat-dependent sexual dimorphism in cave- vs. surface populations of the Asellus aquaticus (Crustacea: Isopoda: Asellidae) species complex.

Studying parallel evolution (repeated, independent evolution of similar phenotypes in similar environments) is a powerful tool to understand environment-dependent selective forces. Surface-dwelling species that repeatedly and independently colonized caves provide unique models for such studies. The primarily surface-dwelling Asellus aquaticus species complex is a good candidate to carry out such research, because it colonized several caves in Europe. By comparing 17 functional morphological traits between six cave and nine surface populations of the A. aquaticus species complex, we investigated population divergence in morphology and sexual dimorphism. We found habitat-dependent population divergence in 10 out of 17 traits, likely reflecting habitat-driven changes in selection acting on sensory systems, feeding, grooming, and antipredator mechanisms. Sexual dimorphism was present in 15 traits, explained by sexual selection acting on male traits important in male-male agonistic behavior or mate guarding and fecundity selection acting on female traits affecting offspring number and nursing. In eight traits, the degree of sexual dimorphism was habitat dependent. We conclude that cave-related morphological changes are highly trait- and function-specific and that the strength of sexual/fecundity selection strongly differs between cave and surface habitats. The considerable population variation within habitat type warrants further studies to reveal cave-specific adaptations besides the parallel patterns.

No room for males in caves: Female-biased sex ratio in subterranean amphipods of the genus Niphargus.

Sex allocation theory predicts that the proportion of daughters to sons will evolve in response to ecological conditions that determine the costs and benefits of producing each sex. All else being equal, the adult sex ratio (ASR) should also vary with ecological conditions. Many studies of subterranean species reported female-biased ASR, but no systematic study has yet been conducted. We test the hypothesis that the ASR becomes more female-biased with increased isolation from the surface. We compiled a data set of ASRs of 35 species in the subterranean amphipod Niphargus, each living in one of three distinct habitats (surface-subterranean boundary, cave streams, phreatic lakes) representing an environmental gradient of increased isolation underground. The ASR was female-biased in 27 of 35 species; the bias was statistically significant in 12 species. We found a significant difference in the ASR among habitats after correction for phylogeny. It is most weakly female-biased at the surface-subterranean boundary and most strongly female-biased in phreatic lakes. Additional modelling suggests that the ASR has evolved towards a single value for both surface-subterranean boundary and cave stream-dwelling species, and another value for 9 of 11 phreatic lake dwellers. We suggest that a history of inbreeding in subterranean populations might lower inbreeding depression such that kin selection favours mating with siblings. This could select for a female-biased offspring sex ratio due to local mate competition among brothers. The observed patterns in sex ratios in subterranean species make them a group worthy of more attention from those interested in sex allocation theory.

[Influence of non-alcoholic fatty liver disease on geno- and immunotoxic alterations of peripheric blood lymphocytes of oil refinery workers]. / A nem alkoholos zsírmáj befolyásoló hatása olajipari munkások perifériás lymphocytáinak gén- és immuntoxikológai paramétereire.

INTRODUCTION: More than half of the Hungarian population is overweight or obese, therefore, non-alcoholic fatty liver is a common problem. According to clinical experience, 20-30% of fatty liver cases is not related to alcohol, but can be linked to diabetes, obesity or metabolic syndrome. AIM: The authors studied the correlation between genotoxicity, immuntoxicity and non-alcoholic fatty liver among oil refinery workers. METHOD: During this genotoxicological monitoring study the data of 107 exposed were compared to 67 controls. RESULTS: 36% of oil refinery workers had non-alcoholic fatty liver, while none of the selected, non-exposed controls had this abnormality. Chromosomal aberrations were elevated from 1.6% to 3.75% in the exposed group, immunotoxicological parameters were also changed, and CD71 positive B-cell ratio increased especially among subjects having non-alcoholic fatty liver. CONCLUSIONS: Non-alcoholic fatty liver can negatively influence the genotoxic effects of environmental hazards in workplaces. In the future this condition should be considered during risk assessment. Orv. Hetil., 2016, 157(35), 1394-1402.

Genotoxic Monitoring of Nurses Handling Cytotoxic Drugs.

OBJECTIVE: Several biomarkers may be used to detect harmful exposure and individual susceptibility to cancer. Monitoring of biomarkers related to exposure may have a significant effect on early detection of cell transformation, thereby aiding the primary prevention of various chronic and malignant diseases. Nurses who handle cytotoxic drugs are exposed to carcinogenic agents, which have the potential to interrupt the cell cycle and to induce chromosomal aberrations. The presence of high chromosomal aberrations indicates the need for intervention even when exposure to these carcinogens is low. METHODS: Nationally representative samples of 552 nurses were investigated by a follow-up monitoring system. The measured biomarkers were clinical laboratory routine tests, completed with genotoxicological (chromosome aberrations [CAs] and sister chromatid exchanges [SCEs]) and immunotoxicological monitoring (ratio of lymphocyte subpopulations and lymphocyte activation markers) measured on peripheral blood lymphocytes. Results were compared to the data of 140 healthy, age-matched controls. RESULTS: In nurses exposed to cytostatics, we observed a significantly increased frequency of CAs and SCEs compared with those in the controls. Cytostatic drug exposure also manifested itself in an increased frequency of helper T lymphocytes. Genotoxicological and immunotoxicological changes, as well as negative health effects (i.e., iron deficiency, anemia, and thyroid diseases), increased among cytostatic exposed subjects. CONCLUSIONS: These results raised concerns about the protection of nursing staff from chemical carcinogens in the working environment.

Effectiveness and tolerability of perampanel in children and adolescents with refractory epilepsies: first experiences.

OBJECTIVE: This article aims to report the first clinical experiences concerning effectiveness and tolerability of perampanel (PER) in a pediatric population with refractory epilepsies. PATIENTS AND METHODS: This nonsponsored, observational, retrospective survey was conducted through collaboration with multiple centers in Europe. The clinical course of the first pediatric patients treated in these centers with PER was documented with the help of a questionnaire completed by the treating physicians. Effectiveness and adverse effects were evaluated. The study population consisted of 58 patients (mean age, 10.5 years; range, 2-17 years), suffering from various refractory epilepsies, classified as focal epilepsy (n = 36), unclassified generalized epilepsy (n = 12), Lennox-Gastaut syndrome (n = 5), West syndrome (n = 3), and Dravet syndrome (n = 2). RESULTS: The response rate (≥ 50% seizure reduction) after the first 3 months of therapy was 31% (18/58 patients) in total. Complete seizure control was achieved in five patients (9% overall). Aggravation of seizures occurred in five cases (9%). The most frequently occurring adverse effects were reduced vigilance or fatigue (n = 16) and behavioral changes (n = 14). DISCUSSION: PER seems to be effective also in children and adolescents with pharmaco-refractory epilepsies. Tolerability was acceptable.

[Genetic and immune-toxicologic studies on abnormal thyroid functions in hospital employees exposed to cytostatic drugs]. / Citosztatikus kezelést végzo kórházi dolgozók pajzsmirigy-elváltozásainak géntoxikológiai és immuntoxikológiai vonatkozásai.

INTRODUCTION: Environmental exposure to harmful chemicals may produce severe consequences. AIM: The aim of the authors was to perform geno- and immune-toxicological monitoring in female employees occupationally exposed to cytostatic agents in hospitals and compare the findings to those obtained from controls. METHOD: Altogether 642 women working in hospital who were occupationally exposed to cytostatic drugs and 262 control women participated in the study. Frequency of chromosome aberrations, immune phenotype and activation of lymphocytes, and the production of reactive oxygen-species in neutrophil granulocytes were determined. RESULTS: Markedly higher number (n=39) of thyroid alterations was observed among exposed subjects as compared to controls (n=3). In persons with abnormal thyroid functions, the frequency of chromosome aberrations (3.69%) was significantly higher (3.69%) than in exposed subjects without thyroid alterations (2.43%) and in controls (1.70% and 1.60% in control subjects with and without thyroid alterations, respectively). Significantly increased ratio of helper T lymphocytes and decreased ratio of cytotoxic T cells and transferrin-receptor (CD71) expressing B cells were observed in exposed subjects having abnormal thyroid functions as compared to controls. In addition, the ratio of B cells, CD71 expressing T cells and production of reactive oxygen-intermediates was significantly decreased in exposed subjects with thyroid alterations in comparison to exposed subjects without thyroid alterations. CONCLUSIONS: The results indicate increased geno- and immune-toxic effects among exposed subjects having thyroid alterations. Further data are needed to clearly establish the underlying pathophysiological mechanism of this finding.

[Use of comet assay for the risk assessment of oil- and chemical-industry workers]. / Comet assay alkalmazása olaj- és vegyipari exponált dolgozók kockázatbecslésében.

INTRODUCTION: The comet assay is a fluorescent microscopic method that is able to detect DNA strand-breaks even in non-proliferative cells in samples with low cell counts. AIM: The aim of the authors was to measure genotoxic DNA damage and assess oxidative DNA damage caused by occupational exposure in groups exposed to benzene, polycyclic aromatic carbohydrates and styrene at the workplace in order to clarify whether the comet assay can be used as an effect marker tool in genotoxicology monitoring. METHOD: In addition to the basic steps of the comet assay, one sample was treated with formamido-pirimidine-DNA-glycolase restriction-enzyme that measures oxidative DNA damage. RESULTS: An increase was observed in tail moments in each group of untreated and Fpg-treated samples compared to the control. CONCLUSIONS: It can be concluded that occupational exposure can be detected with the method. The comet assay may prove to be an excellent effect marker and a supplementary technique for monitoring the presence or absence of genotoxic effects.

Clinical and radiological dissociation of anti-TNF plus methotrexate treatment in early rheumatoid arthritis in routine care: results from the ABRAB study.

BACKGROUND: Rheumatoid arthritis (RA) is a chronic autoinflammatory joint disease which leads to the destruction of joints and disability of the patients. Anti-tumour necrosis factor (anti-TNF) drugs can halt radiological progression better than conventional DMARDs even in clinical non-responders. METHODS: The efficacy of anti-TNF plus methotrexate (MTX) treatment versus MTX monotherapy on clinical and radiological outcomes were compared in early rheumatoid arthritis (RA) patients in clinical practice by retrospective analysis of an observational cohort.49 early RA patients (group A) on first-line MTX monotherapy and 35 early RA patients (group B) on anti-TNF plus MTX treatment were selected from an observational cohort and evaluated retrospectively focusing on their first twelve months of treatment. Data on disease activity (DAS28) and functional status (HAQ-DI) were collected three monthly. One-yearly radiological progression was calculated according to the van der Heijde modified Sharp method (vdHS). Clinical non-responder patients in both groups were selectively investigated from a radiological point of view. RESULTS: Disease activity was decreased and functional status was improved significantly in both groups. One-yearly radiological progression was significantly lower in group B than in group A. The percentage of patients showing radiological non-progression or rapid radiological progression demonstrated a significant advantage for group B patients. In addition non-responder patients in group B showed similar radiological results as responders, while a similar phenomenon was not observed in patients in group A. CONCLUSIONS: Clinical efficacy within our study was similar for tight-controlled MTX monotherapy as well as for combination treatment with anti-TNF and MTX. However MTX monotherapy was accompanied by more rapid radiological progression and less radiological non-progression. Anti-TNF plus MTX decreased radiological progression even in clinical non-responders supporting the advantage of anti-TNF plus MTX combination in dissociating clinical and radiological effects.

[The effect of Kaqun-water on the immune parameters of healthy volunteers]. / A Kaqun víz hatása egészséges önkéntesek immunológiai paramétereire.

INTRODUCTION: Kaqun-water contains a high amount of stable oxygen, which absorbed through the skin and intestinal tract, increases tissue oxygenation. AIM: The aim of the authors was to evaluate the effect of 21 days of Kaqun-water treatment on the immune parameters of healthy volunteers. METHOD: Subpopulations of lymphocytes were determined by immune phenotyping, and CD25 and CD71 activation antigens were used to assess lymphocyte activation. Production of reactive oxygen intermediates was measured to determine the killing capacity of neutrophil granulocytes. Data was analysed with repeated measures ANOVA. RESULTS: The reactive oxygen intermediate production of neutrophils increased significantly in stimulated samples during three weeks of Kaqun-water treatment. The percent of activated, CD25 positive T and helper T cells, and the ratio of NK cells increased. CONCLUSIONS: The increase in oxygen concentration caused by Kaqun-water treatment affects several immune functions: the killing potential of neurophil granulocytes is enhanced, the activation of lymphocytes shows an increased activity of immune function, and the elevated ratio of NK cells may help combat virally infected and tumorous cells.

Immunotoxicity monitoring of hospital staff occupationally exposed to cytostatic drugs.

The aim of our study was to investigate the immunotoxicity of occupational cytostatic drug exposure, and to assess the possible effect of confounding factors, such as age and smoking. In this human study, the immunotoxic effect of antineoplastic drugs was investigated among 306 nurses working in oncology chemotherapy units. Results were compared to 98 non-exposed women. The immune status of the subjects was characterized by immune phenotyping of peripheral blood lymphocytes by flow cytometry, using monoclonal antibodies against surface antigens (CD3, CD4, CD8, CD19, CD25, CD45, CD56 and CD71). The killing ability of neutrophil leukocytes was assessed by the measurement of reactive oxygen intermediate production. Occupational exposure to antineoplastic drugs caused shifts in the major lymphocyte subpopulations, resulting in a statistically significant increase in the ratio of B cells. Cytostatic drug exposure also manifested itself in a decreased frequency of CD25 positive, activated T lymphocytes, and increased oxidative burst of neutrophil granulocytes, both of which may have a functional impact on the immune system of exposed subjects. In the younger subjects exposure also caused a shift in T cell subpopulations: a reduction in the cytotoxic T cell population lead to an elevated Th/Tc ratio. In the exposed group, smoking increased activation of T lymphocyte subpopulations. In conclusion, we have demonstrated that low dose occupational cytostatic drug exposure is immunotoxic, and age and smoking modify the effect of exposure.

SHMT1 1420 and MTHFR 677 variants are associated with rectal but not colon cancer.

BACKGROUND: Association between rectal or colon cancer risk and serine hydroxymethyltransferase 1 (SHMT1) C1420T or methylenetetrahydrofolate reductase (MTHFR) C677T polymorphisms was assessed. The serum total homocysteine (HCY), marker of folate metabolism was also investigated. METHODS: The SHMT1 and MTHFR genotypes were determined by real-time PCR and PCR-RFLP, respectively in 476 patients with rectal, 479 patients with colon cancer and in 461 and 478, respective controls matched for age and sex. Homocysteine levels were determined by HPLC kit. The association between polymorphisms and cancer risk was evaluated by logistic regression analysis adjusted for age, sex and body mass index. The population stratification bias was also estimated. RESULTS: There was no association of genotypes or diplotypes with colon cancer. The rectal cancer risk was significantly lower for SHMT1 TT (OR = 0.57, 95% confidence interval (CI) 0.36-0.89) and higher for MTHFR CT genotypes (OR = 1.4, 95%CI 1.06-1.84). A gene-dosage effect was observed for SHMT1 with progressively decreasing risk with increasing number of T allele (p = 0.014). The stratified analysis according to age and sex revealed that the association is mainly present in the younger (< 60 years) or male subgroup. As expected from genotype analysis, the SHMT1 T allele/MTHFR CC diplotype was associated with reduced rectal cancer risk (OR 0.56, 95%CI 0.42-0.77 vs all other diplotypes together). The above results are unlikely to suffer from population stratification bias. In controls HCY was influenced by SHMT1 polymorphism, while in patients it was affected only by Dukes' stage. In patients with Dukes' stage C or D HCY can be considered as a tumor marker only in case of SHMT1 1420CC genotypes. CONCLUSIONS: A protective effect of SHMT1 1420T allele or SHMT1 1420 T allele/MTHFR 677 CC diplotype against rectal but not colon cancer risk was demonstrated. The presence of SHMT1 1420 T allele significantly increases the HCY levels in controls but not in patients. Homocysteine could be considered as a tumor marker in SHMT1 1420 wild-type (CC) CRC patients in Dukes' stage C and D. Further studies need to clarify why SHMT1 and MTHFR polymorphisms are associated only with rectal and not colon cancer risk.

Formaldehyde-induced chromosomal aberrations and apoptosis in peripheral blood lymphocytes of personnel working in pathology departments.

Peripheral blood lymphocytes (PBL) of 37 formaldehyde-exposed women from four pathology departments in Hungary were investigated to collect data on the effects of occupational exposures to formaldehyde and to find a possible relationship between in vivo formaldehyde-induced apoptosis and genotoxic effects. The subjects were divided into two groups: 16 donors exposed to formaldehyde together with various organic solvents, and 21 subjects exposed mainly to formaldehyde. The results were compared with 37 controls (all women) without known occupational exposure. Ambient air concentrations of formaldehyde were measured in three work places, and ranged from 0.23 to 1.21mg/m(3) (mean 0.9mg/m(3)). Measures of genotoxicity included the determination of the frequencies of chromosomal aberrations (CA), sister-chromatid exchange (SCE), HPRT mutations (variant frequency, VF) and the measurement of UV-induced unscheduled DNA-repair synthesis (UDS). The percentages of premature centromere division (PCD) and of cells with a high frequency of SCE (HF/SCE) were also scored. Apoptosis and cell proliferation were determined by flow cytometry. In both formaldehyde-exposed groups, the apoptotic activity and the CA levels in PBLs were significantly higher than in controls. The CA were mostly breaks of the chromatid type. In the second group, which was mainly exposed to formaldehyde, CA were slightly lower in comparison with the group exposed to formaldehyde and solvents, which may be attributed to a different rate of elimination of damaged lymphocytes as a consequence of formaldehyde-induced apoptotic activity. In the second group, a significant decrease of VF and a non-significant increase in HF/SCE were found compared with the control and the other group. In conclusion, the results demonstrate that exposure to formaldehyde induces apoptosis and CA, indicating an excess cancer risk among subjects occupationally exposed to formaldehyde. The results also emphasize the importance of the measurement of occupational air pollutants, such as formaldehyde, in order to avoid genotoxic effects in the workers.

Hereditary neuropathy with liability to pressure palsy in childhood.

HNPP is an autosomal-dominant inherited disease clinically characterized by painless, episodic, recurrent peripheral palsy often preceded by minor trauma or toxic damage. It generally develops during adolescence and rarely is reported in childhood. We observed two children with this disease. In one of the cases, also the child's mother is suffering from HNPR Clinical and genetic characteristics of our three patients are summarized in this article.

Chemical safety and health conditions among Hungarian hospital nurses.

In the present study genotoxicological and immunotoxicological follow-up investigations were made on 811 donors including 94 unexposed controls and 717 nurses with various working conditions from different hospitals (The Hungarian Nurse Study). The nurses were exposed to different chemicals: cytostatic drugs, anesthetic, and sterilizing gases, such as ethylene oxide (ETO) and formaldehyde. The measured biomarkers were: clinical laboratory routine tests, completed with genotoxicological (chromosome aberrations [CA], sister chromatid exchange [SCE]), and immune-toxicological monitoring (ratio of lymphocyte subpopulations, lymphocyte activation markers, and leukocyte oxidative burst). The highest rate of genotoxicologically affected donors (25.4%) was found in the group of cytostatic drug-exposed nurses. Comparing geno- and immunotoxicological effect markers, we found that among genotoxicologically affected donors the frequency of helper T cell (Th) lymphocytes, the ratio of activated T and B cells increased, whereas the oxidative burst of leukocytes decreased. In hospitals with lack of protective measures increased CA yields were observed compared to those with ISO 9001 quality control or equivalent measures. Anemia, serum glucose level, thyroid dysfunctions, benign, and malignant tumors were more frequent in the exposed groups than in controls. The hygienic standard of the working environment is the basic risk factor for the vulnerability of nurses. On the basis of these results, it is suggested, that the used cytogenetic and immunological biomarkers are appropriate to detect early susceptibility to diseases. The Hungarian Nurse Study proved that the use of safety measures could protect against occupational exposure at work sites handling cytostatic drugs, anesthetic, and sterilizing gases.

[The state of health of oncology nurses characterized by genetic and immunotoxicologic biomarkers]. / Citosztatikumokkal exponált nôvérek egészségi állapotának jellemzése gén- és immuntoxikológiai módszerekkel.

Statistical data indicate a chronic shortage of work-force due to overwork, ill health state and increased risk of chronic noninfectious diseases in Hungarian health care personnel, which needs investigations in order to decrease the risk. Nurses of oncology units, often exposed to carcinogens when preparing and handling cytostatic drugs, are especially at high risk. In the present publication we report a complex clinical, geno- and immunotoxicology risk assessment of altogether 500 nurses, performed during the last 10 years at various oncology units in Hungary. The obtained results indicate that the health status of nurses at oncology units is better than the Hungarian average, especially of hypertonia and type II diabetes. However, the prevalence of iron deficiency anemia and different thyroid gland diseases is significantly higher than those of the controls matched for sex and age. The results suggest that iron deficiency can potentiate the resistance to insulin, i.e. the persistence of iron deficiency may increase the serum glucose levels and thus the risk of diabetes. Among the studied geno- and immunotoxicology biomarkers, the frequency of chromosome aberrations, sister chromatid exchange and B lymphocytes was significantly increased compared to the matched controls. The obtained alterations demonstrate the occupational exposure of the nurses to cytostatic drugs, thus the introduction of more strict hygienic controls and compliance with the European Union chemical safety regulations is necessary.

[Biomarker indicators of chemoprevention among subjects occupationally exposed to metals]. / A kemoprevenció biomarker indikátorai fémexponáltak körében.

Chemoprevention with chelating agent Humetta for three months was performed, due to anaemia and other haematologic disorders, immunotoxicological alterations and/or increased chromosome aberration rate among galvanisers and goldsmiths occupationally exposed to precious and heavy metals. Twenty-two of altogether 47 subjects took part voluntarily in the chemoprevention, and the rest of the subjects served as untreated controls. Complex clinical laboratory testing including detailed anamneses; genotoxicological and immunotoxicological monitoring were performed before and after administration of chemopreventive agent. After chemoprevention a significant improvement was observed in anaemia and serum glucose levels, while a less marked improvement was found in serum cholesterol levels and liver functions. Altered chromosome aberration and apoptotic cell fraction also tended to normalise after treatment. Immunological parameters were not affected by the treatment. The obtained results may suggest that chemoprevention with chelating agents as Humetta can help in the prevention of harmful effects of occupational exposures to metals.

[Characterization of chemically exposed groups by immunotoxicological methods]. / Immuntoxikológiai vizsgálatok alkalmazása a kockázati csoportok jellemzésében.

At the National Institute of Chemical Safety we have surveyed the immunological status of donors from the oil industry, health services, and metallurgy exposed to different immunotoxic compounds. Their data were compared to those of healthy, non-exposed controls. Our aim was to study the relationship between immunotoxic exposure and immune function, and to establish a system of immunological parameters by which chemical exposure can be specifically monitored. Subpopulations and activation of lymphocytes was measured by flow cytometry, using immunophenotyping of peripheral blood lymphocytes. In the groups exposed to immunotoxic compounds we found an increase in helper, and a decrease in cytotoxic T lymphocytes, leading to a shift in Th/Tc ratios. These phenomena are not substance specific, but relate to chemical exposure. The lymphocytes of exposed groups showed a higher proportion of activated cells, but there was a difference in the expressed activation markers. Our results suggest that characterizing lymphocyte subpopulations and activation markers on PBL of donors is a useful tool in tracking environmental immunotoxic effects.

Characterization of a trypsin-like serine protease of activated B cells mediating the cleavage of surface proteins.

Activated B cells may cleave their surface receptors due to the proteolytic activity on the cell membrane or in its vicinity. We attempted to isolate and characterize the protease(s) responsible for this cleavage. Zymograms prepared from the supernatant and the plasma membrane fraction of activated human B cells and BL41/95 cell line exhibited a 85-90 kDa doublet band with protease activity, while that of resting B cells did not. Soybean trypsin inhibitor (STI), Nalpha-p-tosyl-L-lysine chloromethyl ketone (TLCK) and EDTA treatment abolished the activity of this protease. The excess of Zn(2+) ions in EDTA did not restore the enzymatic activity, while it was completely recovered in the presence of Ca(2+). We affinity-purified a 85-90 kDa protease from the supernatant of BL41/95 cells using STI coupled to Sepharose 4B beads, and measured its kinetic parameters. For the arginyl substrate K(M) was 358+/-59 microM and for the lysyl substrate 582+/-103 microM. TLCK and benzamidine inhibited the protease at micromolar, while STI at nanomolar concentrations. Both the inhibition profile and the substrate specificity suggest that it is a trypsin-like serine protease. We assume that the 85-90 kDa serine protease expressed on and secreted by activated B cells and BL41/95 cell line is responsible for the cleavage of various membrane proteins, including Fcgamma receptors; thus it may play a crucial role in regulating B cell's function.

Lymphocyte phenotype analysis and chromosome aberration frequency of workers occupationally exposed to styrene, benzene, polycyclic aromatic hydrocarbons or mixed solvents.

The aim of our study was to investigate the immunotoxicity of benzene, styrene and polycyclic aromatic hydrocarbon exposure, to establish the correlation between immunological and genotoxicological parameters, and to assess the possible effect of confounding factors such as age and smoking. The immune status of the donors was characterized by measuring the surface antigens of peripheral lymphocytes. The studied antigens were the following: CD3, CD4, CD8, CD14, CD19, CD25, CD38, CD45, CD45RO, CD54, CD56, CD62L, CD71 and HLA-DR. In our studies, we compared the immunological and genotoxicological parameters (chromosome aberration, sister chromatid exchange frequency, unscheduled DNA synthesis) of the different groups with healthy controls. Analysis revealed changes in the expression of surface antigens on peripheral lymphocytes in correlation with exposure. Confounding factors, such as smoking, increased the proportion of CD4 positive T lymphocytes and influenced the surface expression of several antigens. In our investigation the occurrence of chromosome aberrations negatively correlated with CD25 (IL-2R) expression in both CD4 and CD8 positive T cells. The presented data suggest that solvents such as benzene, styrene and PAHs activate peripheral lymphocytes, and cause changes in the incidence of CD25+/CD4+ T lymphocytes that may represent a distinct subset of immune-regulatory T cells.