Haematological evaluation of Wistar rats exposed to chronic doses of cadmium, mercury and combined cadmium and mercury

Cadmium and mercury present in the environment, cause blood disorders. This study was conducted to evaluate the influence of cadmium, mercury and their combination on hematological parameters of Wistar rats. For this purpose, two different doses of each metal and their combination were administered orally for 28 days to six groups of five rats each. Two groups (A and B) were respectively exposed to CdCl2 (0.25 and 2.5 mg/kg), two other groups (C and D) respectively received HgCl2 (0.12 and 1.2 mg/kg) and the last two groups (E and F) were respectively treated with the combination of these two metals: (0.25 mg/kg Cd + 0.12 mg/kg Hg) and (2.5 mg/kg Cd + 1.2 mg/kg Hg). The control group (G) received the same volume of distilled water. At the end of exposure, bodies of rats were weighed and the whole blood was collected by retro-orbital sinus method for analysis of hematological parameters. The results of this study show a significant decrease (p<0.05) in white blood cells (WBC) in the lot treated with the combination (0.25 mg/kg Cd + 012 mg/kg Hg) and also indicate a significant decrease (p<0.05) in WBC, red blood cells (RBC), hemoglobin concentration (HGB) and the mean corpuscular hemoglobin concentration (MCHC) with high levels of mercury (2.5 mg/kg) and the combination (2.5 mg/kg Cd + 1.2 mg/kg Hg). An increase in the number of platelet count (PLT) in all intoxicated lots was observed.Keywords: Cadmium, mercury, hematology, blood parameters, ratsAfrican Journal of BiotechnologyVol. 12(23), pp. 3731-373

Genotoxicity assessment of a pharmaceutical effluent using four bioassays

Pharmaceutical industries are among the major contributors to industrial waste. Their effluents when wrongly handled and disposed of endanger both human and environmental health. In this study, we investigated the potential genotoxicity of a pharmaceutical effluent, by using the Allium cepa, mouse- sperm morphology, bone marrow chromosome aberration (CA) and micronucleus (MN) assays. Some of the physico-chemical properties of the effluent were also determined. The A. cepa and the animal assays were respectively carried out at concentrations of 0.5, 1, 2.5, 5 and 10%; and 1, 5, 10, 25 and 50% of the effluent. There was a statistically different (p < 0.05), concentration-dependent inhibition of onion root growth and mitotic index, and induction of chromosomal aberrations in the onion and mouse CA test. Assessment of sperm shape showed that the fraction of the sperm that was abnormal in shape was significantly (p < 0.05) greater than the negative control value. MN analysis showed a dose-dependent induction of micronucleated polychromatic erythrocytes across the treatment groups. These observations were provoked by the toxic and genotoxic constituents present in test samples. The tested pharmaceutical effluent is a potentially genotoxic agent and germ cell mutagen, and may induce adverse health effects in exposed individuals

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency–Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Reproductive toxicity assessment of Olusosun municipal landfill leachate in Mus musculus using abnormal sperm morphology and dominant lethal mutation assays

Mixture of xenobiotics in Olusosun landfill leachates (OSL) induced somatic and germ cell genotoxicity in eukaryotic cells. However, whether the DNA-damaged germ cells can increase reproductive failure, embryotoxicity and/or teratogenicity during fertilization remained unclear. The study herein investigated reproductive toxicity and embryotoxic effects of OSL in mice using abnormal sperm morphology and dominant lethal mutation assays. Six mice per group were exposed to 0.5 mL of 5, 10, 25, and 50% OSL (v/v, leachate/distilled water) for 5 consecutive days. Similar treatment was giving to distilled water and cyclophosphamide (20 mg/kg body weight), as negative and positive control groups, respectively. At 35 day post-treatment, the mice were sacrificed and examined for cauda epididymal abnormal sperm morphology, testicular weight change and histopathological lesions. Male mice were mated to untreated nulliparous females (1 treated male per 2 untreated females) until vaginal plugs were observed. Pregnant females were sacrificed on 14th day post-mating and uterine content examined for number of implants per female, resorptions, and live and dead fetuses. OSL significantly increased teratozoospermia by 31.02% with amorphous sperm head having the highest frequency and sperm with two heads, the least. Histology of the testes revealed congestion of the interstitial blood vessels, spermatid retention and disorganization of the germinal epithelium from the basal compartment. OSL insignificantly increased absolute and relative testes weights but reduced body weight of exposed mice. There was insignificant induction of dominant lethal mutation, although low fertility was observed in the treated mice. The analyzed physico-chemical parameters and heavy metals/metalloids in OSL were higher than permissible limits. The metals, physico-chemical parameters and other unanalyzed substances in OSL induced abnormal sperm morphology, altered testes pathology, but did not significantly induce dominant lethal mutation in mice. Constituents of OSL are toxic to the male reproductive organs in mice and suggests harmful impact on public health. Indiscriminate disposal of solid wastes in the environment should be prevented

Brain dysfunctions in Wistar rats exposed to municipal landfill leachates

Brain damage induced by Olusosun and Aba-Eku municipal landfill leachates was investigated in Wistar rats. Male rats were orally exposed to 1–25% concentrations of the leachates for 30 days. Catalase (CAT) and superoxide dismutase (SOD) activities, and malondialdehyde (MDA) concentrations in the brain and serum of rats were evaluated; body and brain weight gain and histopathology were examined. There was significant (p < 0.05) decrease in body weight gain and SOD activity but increase in absolute and relative brain weight gain, MDA concentration and CAT activity in both brain and serum of treated rats. The biochemical parameters, which were more altered in the brain than serum, corroborated the neurologic lesions; neurodegeneration of purkinje cells with loss of dendrites, perineural vacuolations of the neuronal cytoplasm (spongiosis) and neuronal necrosis in the brain. The concentrations of Cr, Cu, Pb, As, Cd, Mn, Ni, sulphates, ammonia, chloride and phosphate in the leachate samples were above standard permissible limits. The interactions of the neurotoxic constituents of the leachates induced the observed brain damage in the rats via oxidative damage. This suggests health risk in wildlife and human populations

Liver and kidney dysfunction in wistar rats exposed to municipal landfill leachate. Res. Environ

Abstract There is limited information on the toxicity of landfill leachate on somatic tissues and organs of mammals. The hepatotoxic and nephrotoxic effects of leachates from Olusosun and Aba-Eku landfills in Southwestern Nigeria in Wistar albino rats were investigated. Rats orally exposed to 1 -25 % concentrations of each of the test leachates were examined for clinical signs of toxicity and body weight gain during exposure. Blood, liver and kidney of surviving rats were examined for serum biochemical parameters, organ weight gain and histopathology. Clinical toxicity signs include ungroomed hair, reduced activities, hair loss, laboured breathing, reduced feed and fluid consumption, abscess and muscular disorder. There was concentration dependent sex related significant (p&lt;0.05) decrease in body weight and increase absolute and relative liver and kidney weight gain. The test samples caused increase in aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea and creatinine but decrease albumin and total proteins. These parameters showed sexual dimorphisms. Histopathological lesions in the liver and kidney include mild to severe multifocal degeneration of the hepatocytes, multiple periportal foci, cellular infiltration, interstitial haemorrhage cortical congestion, degenerative epithelia of renal tubules and necrosis. The concentration of heavy metals and anions in the test samples were above standard permissible limits. These findings show the potentials of landfill leachate to induce liver and kidney dysfunction in rat probably via free radical formation and/or direct chemical disruption of the organs. This may be of health risk in animal and human population expose to chemical substances from waste landfills

Experimental modeling of the acute toxicity and cytogenotoxic fate of composite mixtures of chromate, copper and arsenate oxides associated with CCA preservative using Clarias gariepinus (Burchell 1822)

Concurrent occurrence of chromium (Cr), copper (Cu) and arsenic (As) from chromated copper arsenate (CCA) wood preservative in aquatic ecosystems demands that their joint-actions in eliciting toxic effects be assessed for adequate understanding of the health risk they may pose to biota. Clarias gariepinus was exposed to As2O3 , CrO3 and CuO and their composite mixtures (1:1 and 1:1:1) at various concentrations (0 – 600 mg/L) for 96-h to determine the acute toxicity using OECD (1992) protocol. C. gariepinus was then exposed to sub-lethal concentrations corresponding to 6.25, 12.5, 25.0, 50.0 and 100% of the 96-h LC50 for 7 days to assess the cytogenotoxic effects using piscine micronucleus (MN) test. The 96-h LC50 showed that the metals/metalloid demonstrated differential interactions in a concentration dependent pattern. The 96-h LC50 showed that Cr was the most toxic while Cu and As:Cu were indeterminate (Cr &gt; Cr:Cu &gt; As:Cr &gt; As &gt; As:Cr:Cu &gt; Cu = As:Cu indeterminate). Isobologram and synergistic ratio (SR) models predicted antagonistic interaction between Cu:Cr and As:Cr and synergism between As:Cu in the causation of morbidity and mortality of C. gariepinus. Interaction factor model predicted antagonism as common interactive mechanism among the metal/metalloid mixtures in the induction of MN and abnormal nuclear erythrocytes in C. gariepinus. Predicted interactions among the three metals/ metalloid were largely antagonism and synergism towards the induction of acute toxicity and cytogenotoxicity. The models employed herein may be useful in establishing environmental safe limits for mixtures of metals/metalloids against the induction of acute toxicity and DNA damage in lower aquatic vertebrates