Examining the macro-determinants of tourist arrivals in India

The present study analyzes the asymmetric association of exchange rate and world income with inbound tourism demand in India using a recently developed nonlinear autoregressive distributed lag model. For this purpose, the study uses monthly data from January 2003 to December 2020 for inbound tourism demand, real effective exchange rate, and world income as the variables of the model. The study used an asymmetric causality test on the lines of Hatemi-J. The findings confirm the existence of a nonlinear association between exchange rate and tourism demand in the long run. Furthermore, the increases in the world income have a positive and significant effect on tourist arrivals in India. In addition, the findings indicate that exchange rate shocks play a vital role in the long run. The cointegration test is supplemented with nonlinear causality analysis. The causal result depicted positive shocks in the exchange rate and world income sharing a unidirectional causal relationship with tourist arrivals. The result of this research can significantly facilitate the policymakers for devising short-run as well as long-run policies to consolidate the macroeconomic fundamentals such that tourism demand can be enhanced in India.

Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC

DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6  ×  6  ×  6 m 3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties.

Prospects for beyond the Standard Model physics searches at the Deep Underground Neutrino Experiment: DUNE Collaboration

The Deep Underground Neutrino Experiment (DUNE) will be a powerful tool for a variety of physics topics. The high-intensity proton beams provide a large neutrino flux, sampled by a near detector system consisting of a combination of capable precision detectors, and by the massive far detector system located deep underground. This configuration sets up DUNE as a machine for discovery, as it enables opportunities not only to perform precision neutrino measurements that may uncover deviations from the present three-flavor mixing paradigm, but also to discover new particles and unveil new interactions and symmetries beyond those predicted in the Standard Model (SM). Of the many potential beyond the Standard Model (BSM) topics DUNE will probe, this paper presents a selection of studies quantifying DUNE's sensitivities to sterile neutrino mixing, heavy neutral leptons, non-standard interactions, CPT symmetry violation, Lorentz invariance violation, neutrino trident production, dark matter from both beam induced and cosmogenic sources, baryon number violation, and other new physics topics that complement those at high-energy colliders and significantly extend the present reach.

Genetic and pharmacological antagonism of NK1 receptor prevents opiate abuse potential

Development of an efficacious, non-addicting analgesic has been challenging. Discovery of novel mechanisms underlying addiction may present a solution. Here we target the neurokinin system, which is involved in both pain and addiction. Morphine exerts its rewarding actions, at least in part, by inhibiting GABAergic input onto substance P (SP) neurons in the ventral tegmental area (VTA), subsequently increasing SP release onto dopaminergic neurons. Genome editing of the neurokinin 1 receptor (NK1R) in the VTA renders morphine non-rewarding. Complementing our genetic approach, we demonstrate utility of a bivalent pharmacophore with dual activity as a μ/δ opioid agonist and NK1R antagonist in inhibiting nociception in an animal model of acute pain while lacking any positive reinforcement. These data indicate that dual targeting of the dopaminergic reward circuitry and pain pathways with a multifunctional opioid agonist-NK1R antagonist may be an efficacious strategy in developing future analgesics that lack abuse potential.

Evaluation of the mutagenic and genotoxic effects of the ALC67 thiazolidine compound in Salmonella strains and human lymphocytes in vitro

ALC67 is an N-acylated thiazolidine compound with promising anticancer activity that led to the recent discovery of a series of 3-propionyl thiazolidine-4-carboxylic acid ethyl esters as a family of novel antiproliferative agents. Since the mutagenic and genotoxic properties of marketed anticancer molecules constitute a main issue to be addressed, this study focused on the analysis of the mutagenicity, antimutagenecity, and genotoxicity of this molecule. The mutagenicity and antimutagenicity of ALC67 were evaluated by Ames test performed on Salmonella TA98 and TA100 strains. The genotoxicity of this molecule was investigated in the chromosomal aberration assay on human lymphocytes. All results revealed that the analyzed structure is not mutagenic in the two Salmonella strains tested and was not genotoxic in human lymphocytes in vitro On the other hand, it showed a weak antimutagenic effect in these two bacterial strains. The above results indicate that after performing some more mutagenicity assays using the other recommended strains, this compound can be safely used for the development of new structures exhibiting anticancer activities.

MAGNETOCALORIC RESPONSE OF NON-STOICHIOMETRIC Ni2MnGa ALLOYS AND THE INFLUENCE OF CRYSTALLOGRAPHIC TEXTURE

Currently, there is significant interest in magnetocaloric materials for solid state refrigeration. In this work, polycrystalline Heusler alloys belonging to the Ni2+xMn1-xGa family, with x between 0.08 and 0.24, were evaluated for the purpose of finding composition(s) with an enhanced magnetocaloric effect (MCE) close to room temperature. Differential scanning calorimetry (DSC) was successfully used to screen alloy composition for simultaneous magnetic and structural phase transformations; this coupling needed for a giant MCE. The alloy with x = 0.16 showed an excellent match of transformation temperatures and exhibited the highest magnetic entropy change, ΔSM, in the as-annealed state. Furthermore, the MCE increased by up to 84 % with a 2 Tesla (T) field change when the samples were thermally cycled through the martensite to austenite transformation temperature while held under a constant mechanical load. The highest ΔSM measured for our x = 0.16 alloy for a 2 T magnetic field change was -18 J/kg-K. Texture measurements suggest that preferential orientation of martensite variants contributed to the enhanced MCE in the stress-assisted thermally cycled state.

Biosorption of arsenic (III) from aqueous solution by living cells of Bacillus cereus

In this work, removal of arsenic (III) from aqueous solution by living cells (Bacillus cereus), biosorption mechanism, and characterization studies have been reported. B. cereus cell surface was characterized using SEM-EDX and FTIR. Dependence of biosorption on pH of the solution, biosorbent dose, initial arsenic (III) concentration, contact time, and temperature had been studied to achieve optimum condition. The maximum biosorption capacity of living cells of B. cereus for arsenic (III) was found to be 32.42 mg/g at pH 7.5, at optimum conditions of contact time of 30 min, biomass dosage of 6 g/L, and temperature of 30 ± 2 °C. Biosorption data of arsenic (III) are fitted to linearly transformed Langmuir isotherm with R (2) (correlation coefficient) >0.99. The pseudo-second-order model description of the kinetics of arsenic (III) is successfully applied to predict the rate constant of biosorption. Thermodynamic parameters reveal the endothermic, spontaneous, and feasible nature of sorption process of arsenic (III) onto B. cereus biomass. The arsenic (III) ions are desorbed from B. cereus using both 1 M HCl and 1 M HNO(3).

Biosorption of As(V) from aqueous solutions by living cells of Bacillus cereus

In this work, the biosorption of As(V) from aqueous solutions by living cells of Bacillus cereus has been reported. The batch biosorption experiments were conducted with respect to biosorbent dosage 0.5 to 15 g/L, pH 2 to 9, contact time 5 to 90 min, initial concentration 1 to 10 mg/L and temperature 10 to 40 °C. The maximum biosorption capacity of B. cereus for As(V) was found to be 30.04 at pH 7.0, at optimum conditions of contact time of 30 min, biomass dosage of 6 g/L, and temperature of 30 ± 2 °C. Biosorption data were fitted to linearly transformed Langmuir isotherms with R(2) (correlation coefficient) >0.99. Bacillus cereus cell surface was characterized using AFM and FTIR. The metal ions were desorbed from B. cereus using both 1 M HCl and 1 M HNO(3). The pseudo-second-order model was successfully applied to predict the rate constant of biosorption.

Toxicity and bioaccumulation potential of Cr (VI) and Hg (II) on differential concentration by Eichhornia crassipes in hydroponic culture

In this work, the phytoremediation of Cr (VI) and Hg (II) ion from water by an aquatic plant Eichhornia crassipes has been studied. Plants were cultured in a double distillated water with modified Hoagland's nutrient solution at pH 6.8 supplemented with 0, 0.75, 1.50, 2.50, and 4 mg Cr/L as potassium dichromate (K(2)Cr(2)O(7)) and 0, 5, 10, 15, and 20 mg Hg/L as mercuric chloride (HgCl(2)). They were separately harvested after 3, 6 and 9 days. Plants treated with 4 mg/L of Cr (VI) accumulated the highest concentration of metal in roots (1.22 mg/g, dry weight) and shoots (0.24 mg/g, dry weight) after 9 days; while those treated with 20 mg/L of Hg (II) accumulated the highest concentration of metal in roots (4.22 mg/g, dry weight) and shoots (2.43 mg/g, dry weight) after 9 days. Eichhornia crassipes biomass was characterised using AAS, SEM and FTIR. The accumulation and relative growth of metal ions at different concentrations of chromium and mercury solution significantly increased (P<0.05) with the passage of time. The maximum values of bio-concentration factor (BCF) for Cr (VI) and Hg (II) were found to be 413.33 and 502.40 L/kg respectively.

Analysis of T-cell proliferation and cytokine secretion in the individuals exposed to arsenic

Over six million people in nine districts of West Bengal, India are exposed to very high levels of arsenic primarily through their drinking water. More than 300,000 people showed arsenic-induced skin lesions in these districts. This is regarded as the greatest arsenic calamity in the world. Chronic arsenicosis causes varied dermatological signs ranging from pigmentation changes, hyperkeratosis to non-melanocytic cancer of skin, and also malignancies in different internal organs. Higher incidences of opportunistic infections are found in the arsenic-exposed individuals, indicating that their immune systems may be impaired somehow. We have thus investigated the effect of arsenic on T-cell proliferation and cytokine secretion in 20 individuals with arsenic-induced skin lesions and compared the results with 18 arsenic-unexposed individuals. A marked dose-dependent suppression of Concanavalin A (Con A) induced T-cell proliferation was observed in the arsenic-exposed individuals compared with the unexposed ( P < 0.001) individuals. This correlated with a significant decrease in the levels of secreted cytokines by the T cells (TNF-α, IFN-γ, IL2, IL10, IL5, and IL4) in the exposed individuals ( P < 0.001). Thus it can be inferred that arsenic exposure can cause immunosuppression in humans.

Mechanism of erythrocyte death in human population exposed to arsenic through drinking water

Arsenic contamination in drinking water is one of the biggest natural calamities, which has become an imperative threat to human health throughout the world. Abbreviation of erythrocyte lifespan leading to the development of anemia is a common sequel in arsenic exposed population. This study was undertaken to explore the mechanism of cell death in human erythrocytes during chronic arsenic exposure. Results revealed transformation of smooth discoid red cells into evaginated echinocytic form in the exposed individuals. Further distortion converted reversible echinocytes to irreversible spheroechinocytes. Arsenic toxicity increased membrane microviscosity along with an elevation of cholesterol/phospholipid ratio, which hampered the flexibility of red cell membrane and made them less deformable. Significant increase in the binding of merocyanine 540 with erythrocyte membrane due to arsenic exposure indicated disruption of lipid packing in the outer leaflet of the cell membrane resulting from altered transbilayer phospholipid asymmetry. Arsenic induced eryptosis was characterized by cell shrinkage and exposure of phosphatidylserine at the cell surface. Furthermore, metabolic starvation with depletion of cellular ATP triggered apoptotic removal of erythrocytes from circulation. Significant decrease in reduced glutathione content indicating defective antioxidant capacity was coupled with enhancement of malondialdehyde and protein carbonyl levels, which pointed to oxidative damage to erythrocyte membrane. Arsenic toxicity intervened into red cell membrane integrity eventually leading to membrane destabilization and hemoglobin release. The study depicted the involvement of both erythrophagocytosis and hemolysis in the destruction of human erythrocytes during chronic arsenic exposure.

Chromosomal aberrations in arsenic-exposed human populations: a review with special reference to a comprehensive study in West Bengal, India

For centuries arsenic has played an important role in science, technology, and medicine. Arsenic for its environmental pervasiveness has gained unexpected entrance to the human body through food, water and air, thereby posing a great threat to public health due to its toxic effect and carcinogenicity. Thus, in modern scenario arsenic is synonymous with "toxic" and is documented as a paradoxical human carcinogen, although its mechanism of induction of neoplasia remains elusive. To assess the risk from environmental and occupational exposure of arsenic, in vivo cytogenetic assays have been conducted in arseniasis-endemic areas of the world using chromosomal aberrations (CA) and sister chromatid exchanges (SCE) as biomarkers in peripheral blood lymphocytes. The primary aim of this report is to critically review and update the existing in vivo cytogenetic studies performed on arsenic-exposed populations around the world and compare the results on CA and SCE from our own study, conducted in arsenic-endemic villages of North 24 Parganas (district) of West Bengal, India from 1999 to 2003. Based on a structured questionnaire, 165 symptomatic (having arsenic induced skin lesions) subjects were selected as the exposed cases consuming water having a mean arsenic content of 214.96 microg/l. For comparison 155 age-sex matched control subjects from an unaffected district (Midnapur) of West Bengal were recruited. Similar to other arsenic exposed populations our population also showed a significant difference (P < 0.01) in the frequencies of CA and SCE between the cases and control group. Presence of substantial chromosome damage in lymphocytes in the exposed population predicts an increased future carcinogenic risk by this metalloid.

Chromosomal aberrations and sister chromatid exchanges in individuals exposed to arsenic through drinking water in West Bengal, India

Arsenic contamination in groundwater has become a worldwide problem. Currently an unprecedented number of people in West Bengal, India and Bangladesh are exposed to the ubiquitous toxicant via drinking water in exposure levels far exceeding the maximum recommended limit laid down by WHO. This arsenic epidemic has devastated nine districts of West Bengal encompassing an area of 38,865 km(2) leading to various clinical manifestations of chronic arsenicosis. We conducted a human bio-monitoring study using chromosomal aberrations (CA) and sister chromatid exchanges (SCE) as end points to explore the cytogenetic effects of chronic arsenic toxicity in the population of North 24 Parganas, one of the arsenic affected districts in West Bengal. Study participants included 59 individuals residing in this district where the mean level (+/-S.E.) of arsenic in drinking water (microg/l) was 211.70+/-15.28. As age matched controls with similar socio-economic status we selected 36 healthy, asymptomatic individuals residing in two unaffected districts--Midnapur and Howrah where the mean arsenic content of water (microg/l) was 6.35+/-0.45. Exposure was assessed by standardized questionnaires and by detecting the levels of arsenic in drinking water, nails, hair and urine samples. In the exposed group the mean arsenic concentrations in nails (microg/g), hair (microg/g) and urine (microg/l) samples were 9.04+/-0.78, 5.63+/-0.38 and 140.52+/-8.82, respectively, which were significantly high (P<0.01) compared to the corresponding control values of 0.44+/-0.03, 0.30+/-0.02 and 5.91+/-0.49, respectively. Elevated mean values (P<0.01) of the percentage of aberrant cells (8.08%) and SCEs per cell (7.26) were also observed in the exposed individuals in comparison to controls (1.96% and 5.95, respectively). The enhanced rates of CAs and SCEs among the residents of North 24 Parganas are indicative of the cytogenetic damage due to long term exposure to arsenic through consumption of contaminated water.

Antimutagenic effects of black tea (World Blend) and its two active polyphenols theaflavins and thearubigins in Salmonella assays

Almost two thirds of the world population consume tea everyday. Tea is processed differently in different parts of the world to give green (20%), black (78%) or oolong tea (2%). The antimutagenic and anticarcinogenic activities of green tea were extensively investigated compared with those of black tea. Considering the potent antimutagenic effects of green tea we recognized the need to evaluate the antimutagenic effects of black tea (World Blend Tea, Southern Tea Co., Marietta, GA) in Salmonella strains TA97a, TA98, TA100 and TA102 in preincubation tests, both with and without S9 activation. Attempts have also been made to compare the results of the tea extracts with their two active polyphenols theaflavins and thearubigins. Antimutagenicity assays were carried out in bacterial plates treated with different concentrations (1%, 2.5%, 5%, 10% and 20%) of tea extracts against known bacterial mutagens sodium azide, 4-nitro-o-phenylenediamine, cumine hydroperoxide, 2-aminofluorene and danthron. A significant decrease in the number of revertant colonies was observed in the plates treated with 1% to 20% of tea extract plus positive mutagen when compared with positive mutagen only. Both the active polyphenols theaflavins and thearubigins extracted from the black tea (World blend) also showed significant antimutagenic effects against known positive compounds in these strains. In the experiments with S9 activation, the antimutagenic effects were significantly higher. These results indicate that black tea and its two polyphenols have significant antimutagenic effects in Ames Salmonella assays.

Comparative antimutagenic and anticlastogenic effects of green tea and black tea: a review

Tea is the most popular beverage next to water, consumed by over two-thirds of the world's population. It is processed in different ways in different parts of the world to give green, black or oolong tea. Experimental studies have demonstrated the significant antimutagenic and anticlastogenic effects of both green and black tea and its polyphenols in multiple mutational assays. In the present review, we have attempted to evaluate and update the comparative antimutagenic and anticlastogenic effects of green tea, black tea and their polyphenols in different test systems, based on available literature. Existing reports have suggested that the protective effects of black tea is as good as green tea, however, more studies on black tea and its polyphenols are needed before a final conclusion can be made.

Enhanced frequency of micronuclei in individuals exposed to arsenic through drinking water in West Bengal, India

In West Bengal, India arsenic in ground water has been found to be above the maximum permissible limit in seven districts covering an area of 37,493km2. In the present study, evaluation of the micronuclei (MN) formation in oral mucosa cells, urothelial cells and peripheral blood lymphocytes was carried out in the symptomatic individuals exposed to arsenic through drinking water. Forty five individuals with cutaneous signs of arsenicism from four affected districts (368.11 microg/l of As in drinking water) were considered as the exposed group and 21 healthy individuals with no symptoms of arsenic poisoning and residing in two unaffected districts (5.49 microg/l of As) were considered as controls. The exposed and control groups had similar age distribution and socioeconomic status. Standardised questionnaires were utilised and medical examination was conducted to ascertain exposure history, sociodemographic characteristics, diet, health, medication, addiction and chief symptoms in the study participants. Arsenic exposure was confirmed by measuring the arsenic content in the drinking water, nails, hair and urine samples from the volunteers. Arsenic contents in the urine, nail and hair in the exposed group were 24.45 microg/l, 12.58 and 6.97 microg/g, respectively which were significantly high in comparison to corresponding control group values of 4.88 microg/l, 0.51 and 0.34 microg/g, respectively. Exposed individuals showed a statistically significant increase in the frequency of MN in oral mucosa, urothelial cells and lymphocytes (5.15, 5.74 and 6.39/1000 cells, respectively) when compared with the controls (0.77, 0.56 and 0.53/1000 cells, respectively). Thus, the above results indicate that the symptomatic individuals exposed to arsenic through drinking water in this region have significant cytogenetic damage.

Anticlastogenic effects of d- and l-centchroman in Swiss albino mice. 2. Subacute study in vivo and comparison with tamoxifen

The antimutagenic effects of the two enantiomers of centchroman, a nonsteroidal oral contraceptive, were evaluated and compared with tamoxifen, a known breast cancer drug. Anticlastogenic assays in subacute in vivo studies in Swiss albino mice were used. They revealed that both d-centchroman and I-centchroman reduced the chromosome aberrations produced by dimethylbenz(a)anthracene and cyclophosphamide, when compared with the group treated only with the former mutagen. Tamoxifen also reduced the chromosome aberrations produced by the two mutagens. Overall the results showed that l-centchroman alone was more effective in reducing cyclophosphamide-induced aberrations than d-centchroman, and for toxicity reasons may be an alternative to tamoxifen in breast cancer therapy.

Nucleolar organizer region count and subjective AgNOR pattern assessment (SAPA) score in skin tumors

OBJECTIVE

To study the argyrophilic nucleolar organizer region (AgNOR) count and subjective AgNOR pattern assessment (SAPA) score in cytologic and histologic specimens of various skin tumors.

STUDY DESIGN

The study group consisted of 37 patients (14 benign and 23 malignant) of various skin tumors. In all cases, cytology by fine needle aspiration cytology (FNAC), and histological specimens were studied by conventional staining and silver staining for AgNOR.

RESULTS

The mean count in benign tumors in cytologic specimens was 2.08 +/- 0.01, compared with 5.50 +/- 1.12 in malignant tumors (P<0.001). In histologic specimens, mean count was 2.13 +/- 0.51 in benign, compared with 5.38 +/- 1.10 in malignant tumors (P<0.001). The SAPA score in benign tumors (P<0.001) in cytologic specimens, was 6.07 +/- 0.83, compared with 10.65 +/- 1.27 in malignant tumors, and in histology, it was 6.07 +/- 0.87 in benign, compared with 10.83 +/- 1.15 in malignant tumors (P < 0.001). Melanoma showed the higher AgNOR count compared with squamous cell carcinoma and basal cell carcinoma. The parameters were statistically significant between the grade of tumor in squamous cell carcinoma and the positivity of lymph nodes as demonstrated by SAPA score. No correlation was found between the clinical stage and Clark level of melanoma. Although, AgNOR count and SAPA score showed similar results, the indicators of validity were higher in SAPA than AgNOR count.

CONCLUSION

Although, AgNOR count and SAPA score gave similar results, but the indicators of validity were higher in SAPA score than AgNOR count.

Anticlastogenic effects of black tea (World blend) and its two active polyphenols theaflavins and thearubigins in vivo in Swiss albino mice

This study investigated the inhibition of cyclophosphamide (CP) and dimethylbenz(a)anthracene (DMBA) induced genetic damage by black tea (World blend) and its two active polyphenols theaflavins (TF) and thearubigins (TR) in Swiss albino mice as measured by chromosome aberrations (CA) and sister chromatid exchanges (SCE). Three different concentrations (5, 10 and 20%) of tea and a single dose of TF and TR were tested for their anticlastogenic effects against DMBA (50 mg/kg body weight) and CP (20 mg/kg for CA and 10 mg/kg for SCE). A significant decrease in CA was observed in all the three concentrations of tea extract plus DMBA treated groups when compared with the respective DMBA treated group alone. Similarly a significant decrease in CA was observed in all the three concentrations of tea extracts plus CP treated series when compared with the group treated with CP alone. In SCE assay, a significant decrease in SCE was observed in 5, 10 and 20% black tea extract plus CP and 10 and 20% tea extracts plus DMBA treated groups when compared with the CP or DMBA treated group alone. In the single dose of TF and TR treated groups a significant decrease in both CA and SCE was observed in both the TF and TR plus both the carcinogen treated groups when compared with their positive controls. The protective effects of black tea extracts were more significant than that of its two polyphenols. This study indicates that both black tea and its active polyphenols TF and TR have significant anticlastogenic effects in bone marrow cells of mice.

Genetic toxicology of a paradoxical human carcinogen, arsenic: a review

Arsenic is widely distributed in nature in air, water and soil in the form of either metalloids or chemical compounds. It is used commercially, as pesticide, wood preservative, in the manufacture of glass, paper and semiconductors. Epidemiological and clinical studies indicate that arsenic is a paradoxical human carcinogen that does not easily induce cancer in animal models. It is one of the toxic compounds known in the environment. Intermittent incidents of arsenic contamination in ground water have been reported from several parts of the world. Arsenic containing drinking water has been associated with a variety of skin and internal organ cancers. The wide human exposure to this compound through drinking water throughout the world causes great concern for human health. In the present review, we have attempted to evaluate and update the mutagenic and genotoxic effects of arsenic and its compounds based on available literature.

Genotoxic effects after in vivo exposure of vegetable extracts containing heavy metals from the Dhapa area of Calcutta, India. I. Effects of cauliflower, spinach and radish

Several reports have indicated that the sewage-fed vegetables of the Dhapa area, near the city of Calcutta, contain a very high amount of heavy metals. Currently 800 ha of land is being utilised throughout the year to cultivate more than eight types of vegetables, with a production of about 147 tonnes per day. A major population of Calcutta consumes these vegetables grown in the Dhapa area. Recently there has been huge pressure on the State Government to ban vegetables grown in the Dhapa area for human consumption. For this reason, we have studied the genotoxic effects of some of the most commonly used vegetable extracts from the Dhapa area after in vivo acute exposure in mice as measured by chromosomal aberrations (CA) and sister chromatid exchanges (SCE) to find out the minimum threshold dose to induce CA and SCE. Three different concentrations of the three most commonly used vegetable extracts (cauliflower, spinach, radish) were fed by gavage to mice for the study of CA and SCE. A significant increase in CA was observed only at the highest concentration of all the vegetable extract-treated groups when compared with the solvent control. A significant increase in SCE were observed in the middle and high doses of spinach and only the high dose of cauliflower and radish extract-treated series when compared with distilled water control. The lowest dose was equivalent to approximately 1 kg of vegetables consumed by a human (60 kg body weight) in a day. The middle and high doses of each vegetable extract were much higher than the normal amount of vegetables that a human can consume per day. So the minimum dose for inducing SCE and CA was much higher than the amount a human can consume in a day. Therefore this study indicates that these vegetables are safe for human consumption up to a certain limit, and attention should be given to reducing the heavy metal contents in the soil and sewage of the Dhapa area to thus reduce the heavy metal concentrations in the vegetables.

Antimutagenic effects of centchroman--a contraceptive and a candidate drug for breast cancer in multiple mutational assays

Centchroman (CC), a non-steroidal oral contraceptive and a candidate drug for breast cancer, has been reported to exhibit partial to complete remission of lesions in 40.5% of breast cancer patients. The potent anti-oestrogenic activity, negligible side-effects and anti-breast cancer activity of CC prompted us to evaluate the antimutagenic effects of this compound in a bacterial mutagenicity assay and CHO/HPRT and AS52/GPT mutation assays in vitro and in vivo in female Swiss albino mice as measured by both sister chromatid exchange (SCE) and chromosome aberrations (CA) against three known positive mutagen compounds, dimethylbenz[a]anthracene (DMBA), cyclophosphamide (CP) and mitomycin C (MMC). Antimutagenicity assays in Salmonella strains TA97a, TA100, TA98 and TA102 were carried out against commonly used known positive mutagens, sodium azide, 4-nitro-o-phenylenediamine, cumine hydroperoxide, 2-aminofluorene and danthron. A significantly reduced number of bacterial histidine revertant colonies was observed in the plates treated with 0.1, 1, 5 and 10 microg/plate CC and a positive compound when compared with bacterial plates treated with the respective positive compound alone. Ethyl methanesulfonate (EMS), a commonly used positive mutagen for CHO/HPRT and AS52/GPT gene mutation assays, was used for antimutagenicity assay in these cells. CC exhibited protective effects against the mutagenicity of EMS in these two mammalian cell mutation assays, CHO/HPRT and AS52/GPT. In the in vivo studies, pretreatment with CC reduced DMBA-induced SCE and CA and CP- and MMC-induced CA when compared with the group treated only with the positive compounds. These results indicate that CC can reduce the mutagenic effects of known genotoxic compounds.

Anticlastogenic effects of centchroman and its enantiomers in Swiss albino mice. I. Acute study and their comparison with tamoxifen

Centchroman (CC), a non steroidal oral contraceptive and a candidate drug for breast cancer, has been reported to exhibit partial to complete remission of lesions in 40.5% of breast cancer patients. Recently, we have reported the antimutagenic effects of CC in multiple mutational assays. The potent antioestrogenic activity, negligible side effects, anti-breast cancer activity and antimutagenic effects of CC prompted us to evaluate the anticlastogenic effects of CC and two of its enantiomers. i.e. D-centchroman (DC) and L-centchroman (LC) in the acute in vivo studies in female Swiss albino mice as measured by chromosome aberrations (CA) and sister chromatid exchange (SCE) assays against two known positive mutagen compounds, i.e. dimethylbenz[a]anthracene (DMBA) and cyclophosphamide (CP). The results of anti-mutagenicity assays of CC and its enantiomers have been compared to the known breast cancer drug tamoxifen (TM). CC and LC reduced both DMBA and CP induced CA when compared with the group treated with only DMBA and CP. DC did not reduce the DMBA-induced CA when compared with the DMBA-treated group alone. It reduces only the CP induced CA. TM also reduces both DMBA and CP induced CA when compared with group received only DMBA or CP. SCE were carried out only for LC. A weak but significant decrease in SCE was observed in both LC plus DMBA- and LC plus CP-treated groups when compared with respective positive controls alone. Thus the overall results indicate that both CC and LC are more effective in reducing the genotoxic effects of DMBA and CP than DC.

Comparative antimutagenic effects of D- and L-centchroman and their comparison with tamoxifen in Salmonella assay

Centchroman (CC)--a contraceptive and a candidate drug for breast cancer has been developed by the Central Drug Research Institute. It has been successfully marketed as a contraceptive for last several years. CC has also been reported to exhibit partial to complete remission of lesions in 40.5% breast cancer patients. Recently, we have reported the antimutagenic effects of CC in Ames Salmonella assay and in vivo and in vitro mammalian cells in multiple mutational assay. The potent antimutagenic activity of CC and its anti-breast cancer activity prompted us to evaluate the antimutagenic effects of its enantiomers, i.e., D-centchroman (DC) and L-centchroman (LC) in the Ames Salmonella strains TA97a, TA98, TA100 and TA102 against known bacterial mutagens. Attempts have also been made to compare the results of antimutagenicity assays of CC and its enantiomers with the known breast cancer drug tamoxifen (TM). The main objective was to identify the best suitable form of CC having antimutagenic effects with anticancer profile similar to TM, would replace the latter for toxicity reasons. When mutagenicity assays were carried out with these compounds as expected like CC, none of these enantiomers or TM showed any mutagenic effects in these Salmonella strains. In the antimutagenicity assay a significantly reduced number of bacterial histidine revertant colonies were observed when positive compounds were co-incubated with certain concentrations of LC compared with bacterial plates treated with respective positive compound. This was observed in some concentrations in all the four strains in both plate incorporation and preincubation tests. The protective effects of LC in preincubation tests were slightly more than in plate incorporation tests. Both the DC and TM showed protective effects only in certain concentrations in some strains in either plate or preincubation tests. Thus the above results indicate that LC showed more protective effects in Salmonella strains TA97a, TA98, TA100 and TA102 than either DC or TM.

Mutagenic and genotoxic effects of theophylline and theobromine in Salmonella assay and in vivo sister chromatid exchanges in bone marrow cells of mice

The mutagenic and genotoxic effects of two methylxanthines, theophylline (TH) and theobromine (TB), were assessed in the Ames mutagenicity assay (in strains TA97a, TA100, TA102 and TA104) and in vivo sister chromatid exchanges (SCEs) in bone marrow cells of mice. These are the two most commonly used nervous system stimulators throughout the world. TH is used in the long-term treatment of asthma. Bacterial mutagenicity assay showed very weak mutagenic effects of both drugs in Salmonella strains TA102 and TA104 only in certain concentrations when S9 was added to it. No mutagenic effects were observed in any other strains used in this assay either with or without metabolic activation. But results of in vivo SCE assay indicate that these two drugs can induce significant SCE in bone marrow cells of mice.

Mutagenicity assay in Salmonella and in vivo sister chromatid exchange in bone marrow cells of mice for four pyrazolone derivatives

Phenylbutazone (PB), oxyphenbutazone (OPB), antipyrine (AP) and dipyrone (DP) are four important pyrazolone derivatives mainly used as anti-inflammatory, antipyretic and analgesic drugs. At present these are the most widely used pyrazolone derivatives throughout the world. The widespread use of these drugs are of great concern for human health problems. In the present study these four drugs were tested in mutagenicity assays in Salmonella strains TA97a, TA98, TA100 and TA102 using a plate incorporation assay both with and without S-9 mix and for in vivo sister chromatid exchanges (SCE) in bone marrow cells of mice. The first three drugs were negative in all the tester strains but dipyrone showed a weak mutagenic activity at higher concentrations in all four strains both with and without metabolic activation. In the in vivo SCE assay in male mice, all four drugs showed a statistically significant increase in SCE in bone marrow cells when compared with control.

Comparative mutagenic and genotoxic effects of three antimalarial drugs, chloroquine, primaquine and amodiaquine

Comparative mutagenic and genotoxic effects of three antimalarial drugs, chloroquine, primaquine and amodiaquine, were assessed in the Ames mutagenicity assay (in strains TA97a, TA100, TA102 and TA104) and in vivo sister chromatid exchange (SCE) and chromosome aberration (CA) assays in bone marrow cells of mice. These are the most commonly used antimalarial drugs available at present throughout the world. The results of the bacterial mutagenicity assays showed a very weak mutagenic effect of all three drugs in Salmonella strains TA97a and TA100 both with and without S9 mix and in TA104 only with S9 mix. The results of the in vivo SCE and CA assays indicate that these three drugs are genotoxic in bone marrow cells of mice.

Comparative mutagenic and genotoxic effects of three propionic acid derivatives ibuprofen, ketoprofen and naproxen

The mutagenicity of three propionic acid derivatives, namely ibuprofen, ketoprofen and naproxen, was tested in the Ames mutagenicity assay (in strains TA97a, TA100 and TA102) and in vivo genotoxicity was tested by sister chromatid exchange (SCE) in bone marrow cells of mice. These are the anti-inflammatory drugs frequently used in different parts of the world. Mutagenicity results showed no mutagenic effects in strains TA97a, TA100 and TA102 for all three drugs. Results of in vivo SCE assays indicate that these three drugs are weakly genoxic in bone marrow cells of mice. This is the first report of the Ames mutagenicity assay for ketoprofen and in vivo SCE assay for three drugs.

Genetic toxicology of epichlorohydrin: a review

Epichlorohydrin (ECH) is one of the more commercially important aliphatic epoxides used extensively as an industrial intermediate, a laboratory reagent, and as an insecticide. It is a volatile, colourless liquid with an ethereal odour. It behaves as an alkylating agent. Reports have shown it to cause the respiratory and dermal toxicity in animals and humans. It has also been reported to be carcinogenic in experimental models. Thus, the wide-spread use of this aliphatic epoxide is of great concern in human health problem. The purpose of this paper is to critically review and update the mutagenic and clastogenic effects of ECH based on available literature.

Comparative genotoxicity of six salicylic acid derivatives in bone marrow cells of mice

In vivo sister chromatid exchange (SCE) and chromosome aberrations (CA) were carried out for six salicylic acid derivatives in bone marrow cells of mice. Six salicylic acid derivatives, namely acetyl salicylic acid (aspirin), salicylic acid, salicylamide, sodium salicylate, diflunisal and niclosamide, were used for these experiments. Drugs were administered both intraperitoneally (i.p.) and orally by gavage. Out of these six salicylic acid derivatives tested, only diflunisal and niclosamide showed genotoxicity as measured by both SCE and CA assays. Acetyl salicylic acid and sodium salicylate showed weak genotoxicity as measured by SCE and CA, respectively, only at the highest dose tested.

Genetic toxicology of four commonly used benzodiazepines: a review

Benzodiazepines are a group of drugs which have been extensively used for their activities as an anti-anxiety, sedative, muscle relaxant and anti-convulsant. Benzodiazepines at present are the most commonly prescribed drugs. Some of these drugs are teratogenic and also carcinogenic in experimental animals. The wide human exposure to this group of drugs throughout the world is of great concern for human health. In the present review, we have attempted to evaluate and update the mutagenic and genotoxic effects of four of the most commonly used benzodiazepines, i.e., chlordiazepoxide (CDZ), diazepam (DZ), nitrazepam (NZ) and oxazepam (OZ) based on available literature.

Genetic damage and the inhibition of 7,12-dimethylbenz[a]anthracene-induced genetic damage by the phytoestrogens, genistein and daidzein, in female ICR mice

Populations consuming soybeans have reduced rates of breast, colon and prostate cancer possibly due, in part, to the presence in soybeans of two estrogenic isoflavones, genistein and daidzein. This study investigated the genotoxicity of these soya isoflavones and their interactions with 7,12-dimethylbenz[a]anthracene (DMBA)-induced sister chromatid exchanges (SCE) in bone marrow cells and DNA adduct formations in liver and mammary glands of mice. Groups of female ICR mice were pretreated i.p. with daidzein and/or genistein (10-20 mg/kg per day for 6 days or 50 mg/kg per 12 h for 3 days) or with the solvent, dimethylsulfoxide (DMSO). The mice were implanted with bromodeoxyuridine (BrdU) tablets s.c., and treated with DMBA (50 mg/kg) i.p. and colchicine (4 mg/kg) i.p. 24, 23, and 2 h before sacrifice, respectively. In bone marrow cells. DMBA alone induced 11.73 +/- 1.42 SCE/cell compared to 4.35 +/- 0.83 SCE/cell in the DMSO treated controls (P = 0.001). DMBA induced 20% fewer SCE (P < 0.05) in mice pretreated with daidzein, genistein or a combination of genistein and daidzein (6 x 20 mg/kg per day for 6 days) when compared to mice that received no pretreatments. Genistein at 50 mg/kg per 12 h for 3 days also inhibited DMBA-induced SCE by 20%. However, treatment for 3 days with 50 mg/kg per 12 h of genistein or daidzein alone, or a combination of daidzein plus genistein (without DMBA treatment) also induced more SCE than treatment with only the solvent (DMSO, P < 0.05). Pretreatment with both the low and the high doses of daidzein plus genistein or the high dose of genistein reduced the replication index of bone marrow cells when compared to pretreatment with DMSO (P < 0.05). Pretreatment with genistein reduced DMBA-induced DNA adduct formation by 34%, but this was only marginally significant (P = 0.08) due to the large inter-individual variability in adduct levels. These results show that genistein and daidzein suppress SCE and possibly DNA adduct formation induced by the known carcinogen, DMBA. This response to a low dose isoflavone exposure may be partly responsible for the protective effect against endocrine cancers of soya consumption.

Genetic toxicology of vinyl chloride--a review

Vinyl chloride (VC) is a colorless gas with a mild, sweet odor. It is extensively used in the production of vinyl chloride polymer, copolymer resin, packaging materials, wire and cable coatings as well as in industrial and laboratory intermediates. It is toxic and also carcinogenic in experimental animals. The wide human exposure to this compound in different industries throughout the world causes great concern for human health. In the present review an attempt has been made to evaluate and update the genotoxic effects of vinyl chloride based on the available literature.

The genetic toxicology of paracetamol and aspirin: a review

Paracetamol and aspirin are the two most widely used analgesics available for human use without prescription in several parts of the world. Paracetamol has an antipyretic activity, and aspirin has both antipyretic and anti-inflammatory activities. Characterization of the mutagenicity and clastogenicity of these drugs is essential for their overall safety assessment. In the present review, an attempt is made to evaluate the genotoxic effects of these two widely used analgesics based on available literature.

Genetic toxicology of propylene oxide and trichloropropylene oxide--a review

Aliphatic epoxides are a group of compounds extensively used in industry and as laboratory reagents, and can be produced as metabolic intermediates. An important aliphatic epoxide is propylene oxide, extensively used in the production of propylene glycol and polyols used in the manufacture of polyurethane polymers. The widespread human exposure to propylene oxide is of great health concern. In this review an attempt has been made to evaluate and update the genotoxic effects of propylene oxide and trichloropropylene oxide based on the available literature.