Boron-exposed male workers in Turkey: no change in sperm Y:X chromosome ratio and in offspring's sex ratio.

Boron-associated shifts in sex ratios at birth were suggested earlier and attributed to a decrease in Y- vs. X-bearing sperm cells. As the matter is pivotal in the discussion of reproductive toxicity of boron/borates, re-investigation in a highly borate-exposed population was required. In the present study, 304 male workers in Bandirma and Bigadic (Turkey) with different degrees of occupational and environmental exposure to boron were investigated. Boron was quantified in blood, urine and semen, and the persons were allocated to exposure groups along B blood levels. In the highest ("extreme") exposure group (n = 69), calculated mean daily boron exposures, semen boron and blood boron concentrations were 44.91 ± 18.32 mg B/day, 1643.23 ± 965.44 ng B/g semen and 553.83 ± 149.52 ng B/g blood, respectively. Overall, an association between boron exposure and Y:X sperm ratios in semen was not statistically significant (p > 0.05). Also, the mean Y:X sperm ratios in semen samples of workers allocated to the different exposure groups were statistically not different in pairwise comparisons (p > 0.05). Additionally, a boron-associated shift in sex ratio at birth towards female offspring was not visible. In essence, the present results do not support an association between boron exposure and decreased Y:X sperm ratio in males, even under extreme boron exposure conditions.

Evaluation of FSH, LH, testosterone levels and semen parameters in male boron workers under extreme exposure conditions.

Boric acid and sodium borates are currently classified in the EU-CLP regulation as "toxic to reproduction" under "Category 1B", with hazard statement of H360FD. However, so far field studies on male reproduction in China and in Turkey could not confirm such boron-associated toxic effects. As validation by another independent study is still required, the present study has investigated possible boron-associated effects on male reproduction in workers (n = 212) under different boron exposure conditions. The mean daily boron exposure (DBE) and blood boron concentration of workers in the extreme exposure group (n = 98) were 47.17 ± 17.47 (7.95-106.8) mg B/day and 570.6 ± 160.1 (402.6-1100) ng B/g blood, respectively. Nevertheless, boron-associated adverse effects on semen parameters, as well as on FSH, LH and total testosterone levels were not seen, even within the extreme exposure group. With this study, a total body of evidence has accumulated that allows to conclude that male reproductive effects are not relevant to humans, under any feasible and realistic conditions of exposure to inorganic boron compounds.

Birth weights of newborns and pregnancy outcomes of environmentally boron-exposed females in Turkey.

Boric acid and sodium borates are currently classified as being toxic to reproduction under "Category 1B" with the hazard statement of "H360 FD" in the European CLP regulation. This has prompted studies on boron-mediated reprotoxic effects in male workers in boron mining areas and boric acid production plants. By contrast, studies on boron-mediated developmental effects in females are scarce. The present study was designed to fill this gap. Hundred and ninety nine females residing in Bandirma and Bigadic participated in this study investigating pregnancy outcomes. The participants constituted a study group covering blood boron from low (< 100 ng B/g blood, n = 143) to high (> 150 ng B/g blood, n = 27) concentrations. The mean blood boron concentration and the mean estimated daily boron exposure of the high exposure group was 274.58 (151.81-975.66) ng B/g blood and 24.67 (10.47-57.86) mg B/day, respectively. In spite of the high level of daily boron exposure, boron-mediated adverse effects on induced abortion, spontaneous abortion (miscarriage), stillbirth, infant death, neonatal death, early neonatal death, preterm birth, congenital anomalies, sex ratio and birth weight of newborns were not observed.

Effects of boric acid on cell death and oxidative stress of mouse TM3 Leydig cells in vitro.

BACKGROUND: Boron (B) is an abundant element on earth and presents at physiological pH in the form of boric acid (BA). It has both positive and negative effects on biological systems. BA and sodium borates have been considered as being toxic to the reproduction system in animal experiments. Unfortunately, the molecular mechanism underlying the toxic effects of BA is not fully understood. METHODS: Here, we demonstrate the influence of BA on mouse TM3 Leydig cells which are male reproductive system cells targeted by BA exposure. The cytotoxicity was evaluated by MTT and NRU assays. Annexin V-FITC/PI double staining kit, mitochondria membrane potential (ΔΨm) assay kit with JC-1 and caspase-3 colorimetric assay kit were used to indicate the cell death pathway. To estimate the role of oxidative stress in BA induced toxicity, glutathione (GSH) level, catalase (CAT) and superoxide dismutase (SOD) activities were measured manually. RESULTS: The cell viability assays showed that BA was not cytotoxic within the tested concentrations up to 1000 µM. Sub-toxic concentrations were used for detecting oxidative stress status. BA exposure was significantly reduced GSH level at 1000 µM and CAT activity in a concentration-dependent manner. However, SOD activity was increased at the tested concentrations (100-1000 µM). Moreover, ΔΨm was significantly decreased at 500 and 1000 µM of BA, while caspase-3 activity was not changed apparently. CONCLUSION: These findings demonstrated that BA is not cytotoxic and apoptotic but may slightly induces oxidative stress in TM3 Leydig cells at higher concentrations.

Occupational exposure of dental technicians to methyl methacrylate: Genotoxicity assessment.

Dental technicians may be chronically exposed to methyl methacrylate (MMA), used in the production of dental prostheses. We have studied whether occupational exposure to MMA affects genotoxicity biomarkers such as 8-OHdG formation, comet assay, and buccal micronucleus frequency. MMA exposure was assessed via ambient air analysis. Although no significant differences between exposed and non-exposed individuals were seen with respect to blood genotoxicity measurements, we found a higher level of buccal-cell anomalies in the exposed group.

Photodynamic therapy effect of morpholinium containing silicon (IV) phthalocyanine on HCT-116 cells.

In this study, we investigated the in vitro potential of axially 1-morpholiniumpropan-2-ol disubstituted silicon (IV) phthalocyanine (SiPc) which was synthesized previously, on HCT-116 cells as a photodynamic therapy (PDT) agent. The singlet oxygen and photodegradation quantum yields of SiPc were calculated using UV-vis spectrophotometer. The cytotoxic and phototoxic effects of SiPc were evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. Annexin V-FITC/PI double staining kit, cell cycle kit, and mitochondria membrane potential (ΔΨm) assay kit with JC-1 were used to indicate the cell death pathway. Caspase-3 and ß-catenin protein expressions were evaluated by western blotting. The singlet oxygen and photodegradation quantum yields of SiPc were calculated as 0.73 and 3.64 × 10-4 in DMSO. The cell viability assays showed that IC50 value of SiPc did not reach to 100 µM without irradiation. However, excellent phototoxicity was observed in the presence of SiPc upon light irradiation. The cells undergoing early/late apoptosis significantly increased in the presence SiPc at 5 µM upon light irradiation. Besides, the proportion of cells at S and G2/M phase increased. Moreover, mitochondria membrane potentials significantly decreased at 1 and 5 µM of SiPc with light irradiation. While caspase-3 expression increased, ß-catenin expression significantly decreased on HCT-116 in the presence of SiPc (p < 0.01). The results indicated that the PDT could be related to apoptosis and Wnt/ß-catenin signaling pathway. Based on our findings, SiPc exhibited a significant PDT effect on HCT-116 cells therefore, worthy of more detailed study.

Evaluation of oxidative stress and immune parameters of boron exposed males and females.

There is growing evidence that boron (B) and B compounds are essential nutrients for animals and humans. Besides, B compounds have been suggested to treat inflammation and oxidative stress. As a part of our "Boron Project II" on B-exposed persons in Bandirma and Bigadic (Turkey) between 2014 and 2017, anti-oxidant/pro-oxidant and inflammatory parameters were assessed. In this first large-scale human study biomarkers of oxidative stress such as the enzyme activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and the levels of malondialdehyde (MDA), glutathione (GSH) and 8-hydroxy-2'-deoxy-guanosine (8-OH-dG) were investigated, in relation to B exposure. The immune biomarkers interleukin (IL)-1ra, IL-6, IL-8 and nuclear factor kappa B (NF-κB) levels were included. There was no influence of human exposure to B on the parameters of oxidative stress and inflammation.

Is There an Association Between Extreme Levels of Boron Exposure and Decrease in Y:X Sperm Ratio in Men? Results of an Epidemiological Study.

OBJECTIVES: A negative association between Y:X sperm ratio and high levels of boron exposure was suggested in an epidemiological study conducted in boron mining areas of China. That study, however, was criticized by many authors due to some weaknesses in the study design. The present epidemiological study was designed to corroborate or refute the above-mentioned negative association between boron exposure and Y:X sperm ratio in men. MATERIALS AND METHODS: The study was conducted in a boric acid production zone in Bandirma. One hundred sixty-three male workers voluntarily participated in our study. The workers employed in the boric acid production facilities were assigned as the exposed workers (n=86). The control group was composed of workers employed in the steam power plant, energy supply unit, demineralized water plant, mechanical workshop, etc. (n=77). Blood and semen samples were sampled from the participating workers at the end of the work shift. Y:X sperm ratio in semen samples was determined by fluorescence in situ hybridization. Boron concentrations in semen and blood samples were determined using inductively coupled plasma-mass spectrometry. RESULTS: Boron-mediated adverse effect on the Y:X sperm ratio was not determined in workers in our study even under extreme occupational exposure conditions. The results of our study refute the negative association between Y:X sperm ratio and high levels of boron exposure that was suggested in a previously published epidemiological study conducted in boron mining areas of China. CONCLUSION: The results of our study indicate that boron-mediated adverse effects on the Y:X sperm ratio do not seem possible even under occupational boron exposure conditions.

Novel water soluble BODIPY compounds: Synthesis, photochemical, DNA interaction, topoisomerases inhibition and photodynamic activity properties.

In this study, BODIPY compounds (2, 3, 5 and 6) bearing 3,4-bis(3-pyridin-3-ylpropoxy)benzyl, 4-(3-pyridin-3-ylpropoxy)benzyl groups were synthesized for the first time and further functionalized in a Knoevenagel condensation reaction with 3,4-bis(3-pyridin-3-ylpropoxy)benzaldehyde and 4-(3-pyridin-3-ylpropoxy)benzaldehyde. The water soluble derivatives of BODIPY compounds (3a and 6a) were synthesized by treating BODIPY compounds 3 and 6 with excess iodomethane in DMF. The photochemical properties and DNA binding modes of 3a and 6a were determined using ct-DNA by UV-Vis spectrophotometer and viscometer. DNA cleavage and topoisomerases inhibition properties were studied DNA using agarose gel electrophoresis. Their topoisomerase inhibition mechanisms were investigated at molecular level and correlations with the in vitro results were searched for using molecular docking method. In addition, cytotoxicity and phototoxicity of both compounds were performed on colorectal cancer cells (HCT-116) using MTT assay for 24 h. Annexin V-FITC/PI test was performed to determine the cell death mechanism of 6a induced by irradiation. Finally, 6a-loaded liposomes (LP6a) and PLGA nanoparticles (NP6a) were prepared and their cytotoxic and phototoxic effects were evaluated by MTT assay. The results claimed that 6a had great potential as photosensitizer agent for colorectal cancer owing to its photochemical, DNA interaction and phototoxic properties.

Environmental boron exposure does not induce DNA damage in lymphocytes and buccal cells of females: DNA damage in lymphocytes and buccal cells of boron exposed females.

Boron (B) compounds are essential for plants and animals and beneficial for humans in nutritional amounts. I animals and humans increasing evidence have shown beneficial effects on B compounds on nutrition and on antioxidant status. The genotoxic effects of environmental B exposure in women living in boron-rich and boron-poor areas was examined in this study. For this purpose, the DNA damage in the lymphocytes and buccal cells of females were assessed by Comet and micronucleus (MN) assays respectively. No significant difference was observed in the DNA damage of the lymphocytes of B exposed groups of female volunteers in Comet assay. Even buccal micronucleus (MN) frequency observed in the high exposure group was significantly lower than the low exposure group (p < 0.05). The results of this study came to the same conclusions of the previous studies that boron does not induce DNA damage even under extreme exposure conditions.

Evaluation of the DNA damage in lymphocytes, sperm and buccal cells of workers under environmental and occupational boron exposure conditions.

Industrial production and use of boron compounds have increased during the last decades, especially for the manufacture of borosilicate glass, fiberglass, metal alloys and flame retardants. This study was conducted in two districts of Balikesir; Bandirma and Bigadic, which geographically belong to the Marmara Region of Turkey. Bandirma is the production and exportation zone for the produced boric acid and some borates and Bigadic has the largest B deposits in Turkey. 102 male workers who were occupationally exposed to boron from Bandirma and 110 workers who were occupationally and environmentally exposed to boron from Bigadic participated to our study. In this study the DNA damage in the sperm, blood and buccal cells of 212 males was evaluated by comet and micronucleus assays. No significant increase in the DNA damage in blood, sperm and buccal cells was observed in the residents exposed to boron both occupationally and environmentally (p = 0.861) for Comet test in the sperm samples, p = 0.116 for Comet test in the lymphocyte samples, p = 0.042 for micronucleus (MN) test, p = 0.955 for binucleated cells (BN), p = 1.486 for condensed chromatin (CC), p = 0.455 for karyorrhectic cells (KHC), p = 0.541 for karyolitic cells (KLY), p = 1.057 for pyknotic cells (PHC), p = 0.331 for nuclear bud (NBUD)). No correlations were seen between blood boron levels and tail intensity values of the sperm samples, lymphocyte samples, frequencies of MN, BN, KHC, KYL, PHC and NBUD. The results of this study came to the same conclusions of the previous studies that boron does not induce DNA damage even under extreme exposure conditions.

Synthesis and In Vitro Activity of Polyhalogenated 2-phenylbenzimidazoles as a New Class of anti-MRSA and Anti-VRE Agents.

A series of novel polyhalogenated 2-phenylbenzimidazoles have been synthesized and evaluated for in vitro antistaphylococcal activity against drug-resistant bacterial strains (methicillin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococcus faecium. Certain compounds inhibit bacterial growth perfectly. 11 was active than vancomycin (0.78 µg/mL) with the lowest MIC values with 0.19 µg/mL against methicillin-resistant Staphylococcus aureus, 8 and 35 exhibited best inhibitory activity against vancomycin-resistant Enterococcus faecium (1.56 µg/mL). The mechanism of action for this class of compounds appears to be different than clinically used antibiotics. These polyhalogenated benzimidazoles have potential for further investigation as a new class of potent anti-methicillin-resistant Staphylococcus aureus and anti-vancomycin-resistant Enterococcus faecium agents.

Evaluation of the radioprotective effect of Turkish propolis on foreskin fibroblast cells.

AIM OF STUDY: Propolis is a resinous bee product, rich of polyphenolic compounds and flavonoids. It is known that in different geographic zones its chemical composition varies due to the different plant sources. Many biological properties including antimicrobial, antioxidative, anti-inflammatory, antitumoral, antigenotoxic, antimutagenic, cytostatic activities have been ascribed to propolis. These biological effects are predominantly attributed to its content of polyphenols. In this study, we aimed to evaluate the radioprotective effect of ethanolic extract of Turkish propolis. (EETP) against γ-ray-induced DNA damage on fibroblast cells using comet assay for the first time. MATERIALS AND METHODS: Fibroblast cells were pretreated 15 and 30 min with concentrations of 100, 200 and 300 µg/mL EETP then they were exposed to 3 Gy γ-rays. Amifostine (synthetic aminothiol compound) was used as a positive control. RESULTS: The results showed a significant decrease in γ-ray-induced DNA damage on cells treated with EETP and amifostine when compared to only irradiated cells. (P < 001). CONCLUSION: It was concluded that EETP prevent γ-ray-induced DNA damage in fibroblast cells and might have radioprotective activity.