Carbamate Synthesis from Aromatic Amines and Dimethyl Carbonate Using Lead Acetate as Catalyst

Carbamates are important intermediates in the syntheses of pesticides, herbicides, drugs, polyurethane-based polymers, and other fine and commodity chemicals.

Hematological Parameters in Bufo arenarum Injected With Sublethal Dose of Lead Acetate

Lead has been recognized as a high risk toxic for most organisms including human. The effects of Pb in non-mammalian vertebrates are oprly known, particularly in anuran amphibians. The purpose of this study was to determine the effect of this metal on some hematological parameters of adult Bufo arenarum. It was found that all parameters remained unaltered within normal ranges, with the exception of reticulocyte counts which was significantly increased compared to the in controls (3. 7% vs. 0. 2 % ). It is suggested that the selective change found in reticulocyte count might be considered as an early response of a biomarker to sublethal exposition of Bufo arenarum to lead.

Neuroprotective potential of Indigofera oblongifolia leaf methanolic extract against lead acetate-induced neurotoxicity

Lead （Pb） is one of the most common environmental toxicants, exposure to which can cause significant neurotoxicity and an associated decline in brain function. This study investigated the possible neuroprotective role oflndigofera oblongifolia leaf methanolic extract （IOLME） against lead-induced neurotoxicity. Rats were intraperitoneally injected with lead acetate, with or without IOLME （intragastric administration for 5 days）, and the neuroprotective effect of IOLME was assessed by measuring the lead concentration, redox status （lipid peroxidation, nitric oxide and glutathione）, enzymatic antioxidant activities （superoxide dismutase, catalase, glutathione peroxidase and reductase）, PCR assays of apoptosis markers （Bax and Bcl-2） and histopathology of the brain. The increases in the lipid peroxidation, nitric oxide, and apoptosis, the decreases in the glutathione level and the activity of antioxidant enzymes, and the altered histology of the brain induced by lead acetate were mitigated in the brain of rats pre-treated with IOLME. These findings indicate that IOLME has beneficial effects and it mitigates lead acetate-induced neurotoxicity via its antiox-idant and anti-apoptotic activities.

Hepatic and reproductive toxicity of sub-chronic exposure to dichlorvos and lead acetate on male Wistar rats

Objective:To investigate the hepatic and reproductive toxicity of dichlorvos and lead acetate on male Wistar rats.Methods:Fifteen adult male Wistar rats(170-190 g)were randomly divided into three groups,with 5 rats in each group.Group 1 received 0.5 mL distilled water orally and served as the control group,while groups 2 and 3 were orally treated with 2 mg/kg body weight(b.w.)dichlorvos and 10 mg/kg b.w.lead acetate,respectively,for 55 days.Epididymal sperm,serum follicle stimulating hormone(FSH),luteinizing hormone(LH),testosterone concentrations,testicular 17β-hydroxysteroid dehydrogenase activity(17β-HSD),androgen receptor expression,aspartate aminotransferase(AST),alanine aminotransferase(ALT),testicular oxidant and antioxidant enzymes were evaluated with standard methods.Results:Sperm count,motility,morphology,FSH,LH,testosterone levels,17β-HSD,androgen receptor expression,and catalase activity were significantly reduced in the dichlorvos and lead acetate treated groups as compared with the control group(P<0.05).The liver AST,ALT activities and malondialdehyde concentration were significantly increased in the dichlorvos and lead acetate treated groups as compared with the control group(P<0.05).Conclusions:The reproductive and hepatic toxicity activities of dichlorvos and lead acetate in male Wistar rats are similar.

Ultrastructural and Ultrahistochemical Studies on Rat Hepatocytes under the Effect of Lead Acetate Administration

The present study was carried out to investigate the effect of lead acetate on the ultrastructure of albino rat hepatocytes with special reference to its effect on the mitochondrial and lysosomal activity. Lead acetate was given orally to albino rats at a dose of 1% lead acetate / 100 g body weight, three times / week for one month （Gila）, two months （Glib）, three months （GIIc）. Liver total protein, body / liver weight ratio and cytochrome P-450 value were calculated. Three parts of the liver samples were incubated in media containing adenosine triphosphate, p-nitrophenyl phosphate and 2% glutlraldehyde and prepared for electron microscopy to visualize adenosine triphosphatase, acid phosphatase and the fine structures ofhepatocytes respectively. The main changes of the fine structures was found in the nucleus, as irregularity of the nuclear membrane, clumped heterochromatin and sun radiation of lead inclusion bodies. The cytoplasm was characterized by shortened, dilated rough endoplasmic reticulum, destroyed and hazy mitochondria with increased number of lysosomes with storage secretion. Ultrastructure findings showed hepatocytes damage due to increased hydrolysis enzymes and decreased cytotoxic enzymes （cytochrome P-450） as well as oxidative enzymes that proved the toxic effect of lead according to the duration of exposure.

Exposure to lead and dietary furan intake aggravates hypothalamus-pituitary-testicular axis toxicity in chronic experimental rats

Lead(Pb) and furan are toxic agents, and persistent exposure may impair human and animal reproductive function. We therefore explored the effects of Pb and furan on male rat hypothalamic-pituitary-gonadal reproductive status, oxidative stress, inflammation, and genomic integrity. We found that co-exposure to Pb and furan reduced the activities of testicular function enzymes, endogenous antioxidant levels, total sulfhydryl group,and glutathione. Sperm abnormality, biomarkers of oxidative stress, inflammation, and p53 expression were increased in a dose-dependent manner by treatment with furan and Pb. Typical rat gonad histoarchitecture features were also damaged. Conclusively, co-exposure to Pb and furan induced male reproductive function derangement by decreasing the antioxidant defences in rats, increasing abnormalities in spermatozoa morphology, and reducing reproductive hormone in circulation. These pathophysiological alterations, if persistent, might provide a permissive environment for potentiating reproductive dysfunction and infertility.

Exacerbation of Soft Tissue Lesions in Lead Exposed Virus Infected Mice

Objective To investigate the effect of Lead (Pb) acetate exposure on Semliki forest virus (SFV) pathogenesis in mice. Methods Different doses (62.5, 125, 250 and 500 mg/Kg body weight) of Pb dissolved in normal saline were given to mice by oral intubation in a sub-acute (28 days) and sub-chronic (90 days) regimen followed by SFV infection. Morbidity, mortality, clinical symptoms, mean survival time (MST), changes in body and organ weight, accumulation of lead in soft tissues, virus titre in brain and histopathological alterations were compared between lead exposed and infected groups. Results Early appearance of virus symptoms, increased mortality, decreased MST, enhanced SFV titre and greater tissue damage were observed in lead exposed-SFV-infected mice. Conclusion Pre-exposure to lead increases the susceptibility of mice towards SFV infection. Further studies are suggested in view of the persistence of lead in the environment and the possibility of infection by microbial pathogens.

Neuromodulatory effects of ethyl acetate fraction of Zingiber officinale Roscoe extract in rats with lead-induced oxidative stress

Objective: This study investigated the ameliorative potential of Zingiber officinale Roscoe extract against lead-induced brain damage in rats.Methods: Thirty male rats were divided into 5 groups of 6 rats each. Lead-acetate toxicity was induced by intraperitoneal injection(10 mg/kg body weight(b.w.)) in Groups B–E. Group A(control) and Group B(lead-acetate) were left untreated; vitamin C(200 mg/kg b.w.) was administered to Group C; ethyl acetate fraction from Z. officinale extract(200 and 100 mg/kg b.w.) was administered to Group D and E by oral gavage once daily for 7 days. Changes in the content of some key marker enzymes such as acetylcholinesterase(AChE), butyrylcholinesterase(BChE), monoamine oxidase(MAO), epinephrine, dopamine,Na^+/K^+-ATPase, catalase(CAT), superoxide dismutase(SOD) and glutathione peroxidase(GPx) as well as malonaldehyde(MDA) levels were determined in serum.Results: Exposure to lead acetate resulted in a significant decrease(P < 0.05) in the activities of BChE,AChE, Na^+/K^+-ATPase, SOD, CAT and GPx with a corresponding increase in the levels of MDA, xanthine oxidase, epinephrine, dopamine and MAO relative to the control group. Levels of all disrupted parameters were alleviated by co-administration of Z. officinale fraction and by the standard drug, vitamin C.Conclusion: These results suggest that ethyl acetate fraction of Z. officinale extract attenuates leadinduced brain damage and might have therapeutic potential as a supplement that can be applied in lead poisoning.

Polyphenol-rich Fraction of Terminalia catappa Prevents Chronic LeadAcetate Induced Oxidative Stress and Cardiorenal Toxicities in Rats

Background:Lead(Pb),a naturally occurring environmental contaminant,has been implicated in several pathological conditions of the cardiovascular and renal systems.Objective:The study was designed to evaluate the modulatory roles of the polyphenol-rich fraction of Terminalia catappa on chronic lead acetate-induced cardiovascular and renal toxicities in rats.Methods:Thirty-six rats were randomly selected and divided into six groups of six rats each.Pb toxicity was induced by the administration of 100 mg/L Pb in drinking water for 12 weeks in groups B-F.Groups A and B were left untreated;groups C and D were treated with polyphenol-rich fraction of Terminalia catappa[PRFTC(100 and 200 mg/kg b.w.)];vitamin E(50 mg/kg b.w.)and lisinopril(10 mg/kg b.w.)were administered to groups E and F,respectively.Results:Exposure of rats to Pb induced significantly elevated(P<0.05)primary haemodynamic parameters,severe disseminated congestion of blood vessels and haemorrhages in the cardiac and renal tissues,significantly elevated(P<0.05)markers of oxidative stress markers of inflammation and myocardial infarction,but significantly decreased serum nitric oxide and the systemic antioxidants.Furthermore,rats exposed to Pb showed heightened immune-positive reactions to Caspase-3,a marker of apoptosis,in both renal and cardiac tissues.All manifestations of Pb-associated toxicities in the cardiovascular and renal systems were alleviated by the PRFTC treatment in rats.Conclusion:The polyphenol-rich fraction of T.catappa proved effective in the reduction of oxidative stressmediated derangements of the physiological homeostasis and decreased apoptosis in the cardiovascular and renal systems of rats chronically exposed to lead acetate toxicities and may therefore have therapeutic potential as a supplement that can be applied in chronic lead poisoning。