Modulatory effects of fresh garlic extract on chrysotile asbestos induced genotoxicity: an in vitro study.
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Asbestos, Serpentine↗
Biomedical subjects
Q Rahman
Publications and source records attributed to Q Rahman.
Hsp70 expression and free radical release after exposure to non-thermal radio-frequency electromagnetic fields and ultrafine particles in human Mono Mac 6 cells.
The contemporary urban environment has become increasingly complex in its composition, leading to discussions regarding possible novel health effects. Two factors that recently have received considerable attention are ultrafine particles (UFP; <0.1 microm) produced by combustion processes and emissions from wireless communication devices like mobile phones that emit in the radio-frequency (RF) part of the spectrum. Several studies have shown biological effects of both these exposures in various cell systems. Here we investigate if exposure to UFP (12-14 nm, 100 microg/ml) and RF-electromagnetic fields (EMF; 2 W/kg specific absorption rate (SAR); continuous wave (CW) or modulated (217Hz or GSM-nonDTX)), alone or in combination influences levels of the superoxide radical anion or the stress protein heat-shock protein (Hsp70) in the human monocyte cell line Mono Mac 6. Heat treatment (42-43 degrees C, 1h) was used as positive control for both stress reaction and for heat development in the RF exposure setup. Our results clearly show that Mono Mac 6 cells are capable to internalise UFP, and that this phagocytic activity is connected to an increased release of free radicals. This increase (40-45% above negative control) is stronger than the effect of heat treatment. On the other hand, none of the employed RF exposures showed any effects on free radical levels. Co-exposure of RF and UFP did not potentiate the UFP effect either. Our investigations showed a significantly increased Hsp70 expression level by heat treatment in a time-dependent manner, whereas UFP, RF, or UFP+RF were without any effect. Therefore, we conclude that in the investigated Mono Mac 6 cells, RF exposure alone or in combination with UFP cannot influence stress-related responses.
Blotting, Western↗
Environmental contamination of chrysotile asbestos and its toxic effects on growth and physiological and biochemical parameters of Lemna gibba.
Asbestos was monitored in water, sediment, and aquatic plant samples around an asbestos cement factory. Based on asbestos concentration found in aquatic plants during monitoring, and the propensity of asbestos to cause oxidative stress in animal models, laboratory experiments were conducted to assess toxicity of chrysotile asbestos on an aquatic macrophyte, duckweed (Lemna gibba). L. gibba plants were exposed to two concentrations of chrysotile asbestos (0.5 microg and 5.0 microg chrysotile in 5.0 microl double distilled water) twice per week during a period of 28 days and cultured in medium containing 0.1 g chrysotile/L. Control plants were cultured in medium without chrysotile asbestos. Effect of chrysotile exposure on certain growth and physiological and biochemical parameters was evaluated. An inhibition effect of chrysotile exposure was found on the number of fronds, root length, and biomass. Similar alterations in contents of chlorophyll, carotenoid, total free sugar, starch, and protein were also found. Contrary to effect on these parameters, a dose- and time-dependent increase in efflux of electrolytes, lipid peroxidation, cellular hydrogen peroxide, catalase, and superoxide dismutase activity was found. The results indicate oxidative stress and phytotoxicity of chrysotile asbestos on duckweed.
Araceae↗
Asbestos contamination in biota and abiota in the vicinity of asbestos-cement factory.
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Animals↗
Sexual orientation and the 2nd to 4th finger length ratio: evidence for organising effects of sex hormones or developmental instability?
It has been proposed that human sexual orientation is influenced by prenatal sex hormones. Some evidence examining putative somatic markers of prenatal sex hormones supports this assumption. An alternative suggestion has been that homosexuality may be due to general developmental disruptions independent of hormonal effects. This study investigated the ratio of the 2nd to 4th finger digits (the 2D:4D ratio), a measure often ascribed to the organisational actions of prenatal androgens, and the fluctuating asymmetry (FA-a measure of general developmental disruption) of these features, in a sample of 240 healthy, right handed and exclusively heterosexual and homosexual males and females (N=60 per group). Homosexual males and females showed significantly lower 2D:4D ratios in comparison to heterosexuals, but sexual orientation did not relate to any measures of FA. The evidence may suggest that homosexual males and females have been exposed to non-disruptive, but elevated levels of androgens in utero. However, these data also draw attention to difficulties in the interpretation of results when somatic features are employed as biological markers of prenatal hormonal influences.
Adolescent↗
Smoking enhances asbestos-induced genotoxicity, relative involvement of chromosome 1: a study using multicolor FISH with tandem labeling.
Several experimental and epidermological studies have indicated augmentation of asbestos induced diseases by cigarette smoke by the mechanisms, which are still unknown. To determine whether smoking affects genetic system of the cells and further modifies asbestos induced genotoxicity, whole blood from non-smokers and smokers was exposed to asbestos fibres separately in vitro and micronucleus test was performed. The number of micronuclei was found to be significantly higher (P<0 05) in cases of smoker's lymphocytes, asbestos exposed non-smokers lymphocytes as well as asbestos exposed smokers lymphocytes, as compared with unexposed non-smokers lymphocytes. Further we investigated involvement of chromosome 1 in the damaging process using multicolor FISH technique. FISH is fast and reliable method, distinguishing both structural and numerical alterations. The centric/pericentric regions of chromosome 1 (cen-q12) were labeled, as the pericentric heterochromatin region 1 (q12) is quite large, highly repetitive and prone to breakage. Multicolor FISH assay suggested that the genetic damage by asbestos fibres mainly involve chromosome 1 but in case of cigarette smoking the damage is not strictly connected to chromosome 1 only, but also involves damage to other chromosomes. Further the study suggested that smoking makes genetic system of the cells more vulnerable to the deleterious effects of asbestos.
Adult↗
Pulmonary toxicity of dust generated during weaving of carpets.
The dust generated during weaving (carpet dust) tibbati, knotted and tuffted carpets in carpet industry was studied for its toxicity in vitro and in vivo. Carpet dust (0.5, 1.0, 2.5 and 5.0 mg/1 x 10(6) cells) caused in vitro cytotoxicity in rat alveolar macrophages (AM) in a concentration-dependent manner. The cytotoxic, inflammatory and oxidative responses were observed in bronchoalveolar lavage fluid (BALF) of rats at 1, 4, 8 and 16 days after exposure. Rats were intratracheally exposed at 5 mg/rat individually to all three types of carpet dust. All types of carpet dusts produced increased AM, lymphocytes (PMN) population in BALF suggesting their inflammatory reactions. Cytotoxic nature of carpet dust was shown by the increased activities of lactate dehydrogenase (LDH) and acid phosphatase (AP) in BALF. Increased AM population and in vitro cytotoxicity due to carpet dusts have shown some correlation with the levels of LDH and AP activities in BALF. The gradual enhanced profile of hydrogen peroxide (H2O2) and nitric oxide (NO) along with depletion of reduced glutathione (GSH) in AM due to these carpet dusts are suggestive of their oxidant nature. The enzyme activities of both glutathione peroxidase (GPx) and glutathione reductase (GR) in AM were marginally reduced in exposed rats. In conclusion, the data suggest the cytotoxic, inflammatory and oxidant nature of carpet dusts. It is extrapolated that health effects on carpet weavers would be associated with the concentration and nature of airborne dust generated during weaving of carpets.
Acid Phosphatase↗
Which behaviors constitute "having sex" among university students in the UK?
The aim of this study was to establish which behaviors were considered to constitute sexual relations and to compare a group of undergraduates in the UK with a group in the US. An opportunistic sample of 190 female and 124 male UK undergraduate university students was surveyed by questionnaire. The main outcome measure was percentage of responses to 11 different behaviors believed to constitute "having sex." The majority of respondents regarded having sex as involving penile-vaginal and penile-anal intercourse. One-third of respondents regarded oral-genital contact as having sex, around 17% regarded touching genitals, whilst 6% regarded oral or other touching of breasts and nipples as constituting having sex. There were significant gender- and age-related differences in responses. These findings broadly support the findings of an earlier US study. It is clear that British students hold divergent opinions about which behaviors do and do not constitute having sex. The age-related trends merit further exploration. Any studies of sex-related behaviors need to specify precisely which are encompassed by the terms used.
Adult↗
Can we predict who will return to a genitourinary clinic?
One hundred and eighty-eight first-time attenders at a genitourinary (GU) clinic were monitored to establish who returned following discharge after treatment. Thirty-six (19%) returned within 2 years with a new infection. The re-attenders did not differ significantly from the rest of the cohort by age, gender or occupation, nor did they differ in their sexual history and psychological variables. Re-attenders were significantly more likely to have consulted their general practitioner (GP) in the 6 months prior to their first clinic attendance.
Female↗
International conference on environmental and occupational lung diseases.
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Developing Countries↗
Mutational analysis of N-ras, p53, p16INK4a, p14ARF and CDK4 genes in primary human malignant mesotheliomas.
Nineteen specimens from primary human malignant mesotheliomas obtained from 19 patients were screened for activating point mutations in the oncogenes N-ras and CDK4 by combined RFLP-PCR/SSCP analysis. In addition, all tumours were screened for deletions and point mutations in the tumour suppressor genes p53, p16INK4a (CDKN2A) and p14ARF (exon-1beta) by combined multiplex-PCR/SSCP analysis. No mutations were found in N-ras, p53 and CDK4. Three tumours displayed homozygous deletion (co-deletion of exons 1, 2 and 3) of p16INK4a. One of them displayed additional homozygous deletion of p14ARF (exon-1beta). Two silent point mutations and 2 polymorphisms were found in p16INK4a in 3 tumours. Our preliminary data indicate that disarrangement of the Rb1 pathway may be involved in mesothelioma formation.
Adult↗
N-acetyl L-cysteine attenuates oxidant-mediated toxicity induced by chrysotile fibers.
Chrysotile, an important commercial variety of asbestos, is known to cause oxidative stress by enhancing production of hydrogen peroxide (H(2)O(2)) and thiobarbituric acid reactive substances (TBARS), depleting glutathione (GSH) and altering levels of GSH redox system enzymes. N-acetyl L-cysteine (NAC), a compound that increases GSH levels, protects cells against chrysotile toxicity. In the present study, rats were exposed intratracheally to a single dose (5 mg/rat) of chrysotile. This was followed by a daily dose of NAC 50 mg/kg. b. wt., i.p. At 1, 4, 8 and 16 days post chrysotile exposure lung lavage fluid was collected to determine H(2)O(2) generation, TBARS production, GSH level and its redox system enzymes activities. A significant decrease in H(2)O(2) and TBARS, an increase in GSH content and its redox system enzymes was observed in chrysotile+NAC animals in comparison to chrysotile-exposed animals. In this preliminary study it appears that NAC may be protecting cells against oxidative damage. This protection may be due to its ability to maintain intracellular GSH/oxidative scavenging capability.
Acetylcysteine↗
Kerosene soot genotoxicity: enhanced effect upon co-exposure with chrysotile asbestos in Syrian hamster embryo fibroblasts.
Epidemiological and experimental studies have suggested an enhancement of asbestos-induced bronchogenic carcinoma by cigarette smoke. Further, our recent experimental and epidemiological studies have indicated that besides smoking, several other compounds including kerosene soot may accelerate disease processes in asbestos-exposed animals as well as in the humans. Incomplete combustion of kerosene oil generates large volumes of soot, which contains various polycyclic aromatic hydrocarbons and aliphatic compounds. As reported earlier, exposure to kerosene soot is known to cause biochemical and pathological changes in the pulmonary tissue, which may cause cardiopulmonary disorders. In this study we investigated genotoxic effects caused by kerosene soot and chrysotile asbestos as well as co-exposure of kerosene soot and chrysotile using Syrian hamster embryo fibroblasts (SHE). The micronucleus assay revealed a significant increase of induced micronuclei (MN), (P</=0.05) in SHE cells after treatment with kerosene soot (0.5-1.0 microg/cm(2)) for 66 h (36 MN/1000 cells). Combined treatment with chrysotile and soot induced up to 110 MN/1000 cells (chrysotile alone: 80 MN/1000 cells; concentrations: 1 microg/cm(2), exposure times: 66 h). Kinetochore staining revealed mainly clastogenic effects in all cases (soot: 21.3% CRMN(+); chrysotile: 27%; soot+chrysotile: 27.6%; control: 20.8%). This is the first study showing that kerosene soot is not only genotoxic but it can also elevate the genotoxic potential of chrysotile asbestos. This information may be of importance for workers occupationally exposed to asbestos and domestically exposed to kerosene soot.
Animals↗
Adolescent nutrition in a rural community in Bangladesh.
The objective of this study was to assess the nutritional status of adolescent boys and girls in a rural community in Bangladesh. Between December 1996 and January 1997, a cross-sectional survey was carried out in 803 households, each containing at least one adolescent, sampled consecutively from four purposely-selected villages in Rupganj Thana, Narayanganj district. Initially, the guardians of 1483 healthy and unmarried 10-17 year old adolescents (51% boys and 49% girls) were interviewed about family structure and socio-economic status. Out of these children, 906 (47% boys and 53% girls) from 597 households were weighed, had their height and MUAC measured and were clinically examined. Blood was then collected from 861 adolescents for haemoglobin estimation. The median monthly income per person in these 597 families was approximately Taka 554 (US $12). Twenty seven per cent of the household heads were labourers, 21% were solvent farmers, 14% ran small scale businesses and 6% were unemployed. Sixty seven per cent of adolescents were thin (defined as BMI < 5th centile of WHO recommended reference) with 75% boys and 59% girls being affected. The percentage of thin adolescents fell from 95% at age 10 years to 12% at age 17 years. The prevalence of stunting (height for age < 3rd centile NCHS/WHO) was 48% for both boys and girls and rose from 34% at age 10 to 65% at age 17. On clinical examination angular stomatitis was present in 46%, 27% had glossitis, 38% had pallor, 11% had dental caries, 3.2% had an conspicuously enlarged thyroid and 2.1% had eye changes of vitamin A deficiency. According to INACG (International Nutritional Anaemia Consultative Group, 1985) cut-off values, 94% of the boys and 98% of the girls were anaemic. We conclude that rural Bangladesh adolescents suffer from high rates of malnutrition and almost universal anaemia. Nutritional interventions to target this population are urgently required.
Adolescent↗
Sexual orientation and the sleep-wake cycle: a preliminary investigation.
The sleep-wake cycle as a function of sexual orientation was investigated. Male and female, heterosexual and homosexual subjects completed a sexual-orientation questionnaire and four sets of recording sheets of activities for a 16-day period. Mean sleep duration was calculated from the record sheets using waking-up and going-to-sleep times. It was predicted that homosexual males and females would awake earlier, go to sleep later, and thus have shorter sleep duration compared to heterosexuals. This was supported by the results. Although a sexual orientation by sex interaction just failed to reach significance, additional analyses of the results indicated that differences in sleep duration between heterosexuals and homosexuals were markedly related to sex. The possibility that these results reflect dimorphic features of the human supra-chiasmatic nucleus (SCN) is discussed.
Adult↗
Chrysotile-mediated imbalance in the glutathione redox system in the development of pulmonary injury.
A significant depletion in the content of glutathione (GSH) and alteration in GSH redox system enzymes were observed in the lung of chrysotile-exposed animals (5 mg) during different developmental stages of asbestosis. In the alveolar macrophages (AM) of exposed animals, the depletion in GSH started from day 1 and reached a maximum at day 16, whereas in lung tissue the maximum depletion was observed when fibrosis has matured. It appears that cellular GSH depletion triggers oxidative stress in the system as observed from increased thiobarbituric acid reactive substance (TBARS) production and alteration in the activities of glutathione peroxidase (GPx), glutathione reductase (GR), glucose 6-phosphate dehydrogenase (G6PD) and glutathione S-transferase (GST), the enzymes regulating oxidative tone. The depletion in GSH was also observed in red blood cells (RBC) of the exposed animals reaching a maximum when fibrosis matured. Thus the observed depletion in GSH, ascorbic acid and alteration in GSH redox system enzymes may be involved in fibrosis and carcinogenesis induced by chrysotile.
Animals↗
Glutathione redox system in oxidative lung injury.
Glutathione (GSH) is a ubiquitous intracellular thiol present in all tissues, including lung. Besides maintaining cellular integrity by creating a reduced environment, GSH has multiple functions, including detoxification of xenobiotics, synthesis of proteins, nucleic acids, and leukotrienes. Present in high concentrations in bronchoalveolar lavage fluid (BALF), GSH provides protection to the lung from oxidative injury induced by different endogenous or exogenous pulmonary toxicants. Its depletion in the lung has been associated with the increased risk of lung damage and disease. The redox system of GSH consists of primary and secondary antioxidants, including glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), and glucose 6-phosphate dehydrogenase (G6PD). Alterations in the activities of these enzymes may reflect reduced cellular defense and may serve as surrogate markers of many lung diseases. As GSH is also involved in the regulation of expression of protooncogenes and apoptosis (programmed cell death), the development of diseases such as cancer and human immune deficiency may be affected by depleting or elevating cellular GSH levels. Exogenous delivery of GSH or its precursor N-acetyl cysteine (NAC) is being used as chemotherapeutic approach.
Antioxidants↗
Activation of alveolar macrophages and peripheral red blood cells in rats exposed to fibers/particles.
The cytotoxic and oxidative responses of crocidolite and chrysotile asbestos fibers and ultrafine titanium dioxide (UF-TiO2) particles were measured in alveolar macrophages (AM) and peripheral red blood cells (RBC) of rat after 30 days with a single intratracheal exposure (5 mg). The following responses were observed one month after fiber/particle instillation: (1) AM population increased; (2) lactate dehydrogenase and acid phosphatase activities in cell free lung lavage fluid increased; (3) substances that react with hydrogen peroxide or thiobarbituric acid were elevated in both AM and peripheral RBC; (4) glutathione peroxidase, glutathione reductase, and catalase were altered in both AM and peripheral RBC; (5) glutathione and ascorbic acid decreased in both AM and peripheral RBC. A significant difference from negative controls was noted in all responses of the two fiber-exposed groups, and in most responses of the UF-TiO2-exposed group. The level of responses to the three test substances suggested a decreasing order of toxicity, with crocidolite > chrysotile > UF-TiO2.
Aerosols↗