Effects of boron compounds on human reproduction

Because of the high pKa of boric acid, inorganic borates, when taken up by the human or animal organism, exist in the body almost exclusively in the form of non-dissociated boric acid. Therefore, the variety of inorganic boron compounds is commonly addressed in the toxicological literature as “boron” (B). There is a discussion concerning categorisation of inorganic boron compounds as reproductive toxins. Boron treatment of rats, mice and dogs was dose-dependently associated with testicular toxicity, characterised by inhibited spermiation at lower dose levels and by reduction of epididymal sperm counts at higher dose levels. The NOAEL for such fertility effects of boric acid in male rats (oral feeding, Sprague Dawley strain) was evaluated to be 17.5 mg B/kg bw per day. As far as developmental toxicity is concerned, oral dosing of 9.6 mg B/kg bw daily to female pregnant Sprague Dawley rats remained without effects, with foetal skeletal effects observed at higher doses. Therefore, 9.6 mg B/kg bw (oral dosing) was evaluated as NOAEL for developmental effects of boric acid. The blood level in rats, equivalent to this NOAEL, is 1270 ng B/g. As far as B-exposed humans are concerned, field studies on the effect of boron on human reproduction are possible only in a few boron-rich geographical areas. Published field studies were conducted in China’s Liaoning province, the Argentinian Andes and Western Anatolia/Turkey. Particularly relevant are studies on occupationally B-exposed groups, because the potential exposure to boron is much higher in occupational compared to environmental settings. Comparison of estimated daily B exposure levels in humans and actually measured B blood levels confirms the preference of biomonitoring for exposure assessment in environmental and occupational studies. A boron blood level scaling shows that the levels of high occupational B exposures reported in China and in Turkey are compatible. Compared to the experimental B blood levels at boron-related NOAELs for male fertility and for developmental toxicity in rats, the human blood level means of the highest occupational exposure groups in China and in Turkey are lower by factors of > 4 and > 2, respectively. Basically, concentrations of B within the body that exert reproductive toxicity in humans are not reached under the conditions of human normal handling and use, including conditions of extreme occupational exposures. In consequence, all relevant results of studies into human reproductive toxicity of B are basically negative. Considering the effective doses, there is no scientific contradiction between experimental and human results of B reproductive toxicity

Alterations of neutrophil functions in foundry and pottery workers

To assess the immune competence of workers occupationally exposed to mainly silica, neutrophil functions such as the chemotactic and oxidative burst activity in foundry and pottery workers were evaluated. The chemotactic activity was examined in 22 foundry and 10 pottery workers and oxidative burst activity of neutrophils were determined in 22 foundry and 6 pottery workers. Healthy subjects of comparable age, sex, and smoking habits and with no history of silica exposure were used as the control groups. Chemotaxis was carried out in Boyden chambers using Zymosan activated serum as chemotactic stimulus. Oxidative burst activity was measured using nitroblue tetrazolium (NBT) dye reduction test. Both neutrophil functions were significantly reduced in silica-exposed foundry and pottery workers (p<0.001) compared to controls suggesting that human chronic exposure mainly to silica and other chemicals

Resveratrolün Farklı Hücre Hatlarında MTT ve NKA Yöntemleri ile Değerlendirilen Sitotoksik Etkileri

Oksidatif stres, reaktif oksijen bileşiklerinin üretimi ile antioksidan savunma sistemlerinin dengesinin bozulmasını tanımlayan bir terimdir. Oksidatif stres, inflamasyon kanser, nörodejeneratif bozukluklar ve kardiyovasküler hastalıklar gibi birçok hastalığın gelişmesinde rol oynamaktadır. Bitkisel fenolik bileşiklerin antioksidan etkili oldukları ve bu nedenle anti kanser etkileri oldukları öne sürülmektedir. Resveratrol (RV), üzüm, fındık, yaban mersini ve ahududu gibi pekçok bitkisel üründe bulunan, doğal olarak oluşan polifenolik bir bileşiktir. RV'nin antioksidan, antiinflamatuvar ve antikanser etkileri olduğu gösteren çalışmalar bulunmaktadır. Ancak RV'nin özellikle kanserin önlenmesinde koruyucu etkilerinin olmadığını da iddia edilmektedir. Bu çalışmada, insan meme adenokarsinoma (MDA-MB 231), insan servikal kanser (HeLa) ve Çin hamster akciğer fibroblast (V79) hücrelerinde RV'nin sitotoksik etkileri, 24 saat inkübasyon sonrasında Nötral Kırmızı Alım (NKA) ve 3-(4,5-dimetiltiyazol-2-il)-2,5- difeniltetrazolyum bromür (MTT) yöntemleri ile değerlendirilmiştir. Her iki sitotoksisite yönteminde de benzer sonuçlar elde edilmiştir. 2-400 µM aralığında, RV'ün tüm hücre tiplerinde belirgin bir sitotoksik etkisi olmadığı görülmüştür. Hatta en yüksek konsatrasyonlarda bile neredeyse hiç sitotoksik etkileri olmamıştır. Bu nedenle IC50 değerleri, bu konsantrasyonaralığında hesaplanamamıştır.Oxidative stress is the state of imbalance between the level of antioxidant defence system and production of reactive oxygen species (ROS) and is involded in the progression of several diseases such as inflammation, cancer, neurodegenerative disorders and cardiovascular diseases. It is suggested that plant polyphenols may act as antioxidants and therefore it has anti-cancer activities. Resveratrol (RV), is a naturally occuring polyphenolic compound which is found in many plant species including grapes, nuts, blueberries and raspberries. Data indicated that it has anti-oxidant, anti-inflamatory and anti-cancer activities. But there are also some studies reported that RV has not protective effects aganist cancer. In this study, the cytotoxicity of RV in human breast adenocarcinoma (MDA-MB 231), human cervical cancer (HeLa) and Chinese hamster lung fibroblast (V79) cells were evaluated by Neutral Red uptake assay (NRU) and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assays after incubation at 24 h. We obtained more or the less same results by two cytotoxicity assays. In the concentrations between 2-400 mM, RV seemed not to induce a pronounced cytotoxicity in all cell types. Even at highest concentrations, it showed almost no cytotoxic effects. So the IC50 values were not calculated at the studied concentrations

Monitoring of DNA damage in foundry and pottery workers exposed to silica by the alkaline comet assay

Background Workers in foundry and pottery are exposed to a mixture of chemicals and silica, which is suspected to cause genetic alterations. Methods To investigate the potential hazard associated with the occupational exposure to silica, DNA damage in the peripheral lymphocytes of 30 foundry and 22 pottery workers were examined by the alkaline single‐cell gel electrophoresis or Comet Assay, and compared to 52 healthy subjects with no history of occupational silica or chemical exposure. Results The DNA damage observed in the lymphocytes of both foundry and pottery workers was significantly higher than that in their controls. Cigarette smoking was also related to DNA damage since the DNA damage observed in smoking silica‐exposed workers compared with the non‐smoking workers was significantly higher. Conclusions Occupational exposure of silica from foundry and pottery workplaces has been

Assessment of Dna damage in workers occupationally exposed to hazardous chemicals

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