Development of dog mammary tumor xenograft in immunosuppressed Swiss albino mice.

Development and study of dog mammary tumour xenograft in immunosuppressed Swiss Albino Mice adds a new dimension in cancer research as dog tumors have many similarities with human tumors regarding progression, histopathology, molecular mechanism, immune response and therapy. Failure of the immune system to recognize and eliminate cancer cells leads to cancer progression and the fight between immune cells and cancer cells has a great role in understanding the mechanism of cancer progression and elimination. Rejection and acceptance of tumour xenograft depends on efficiency of CD4+, CD8+ and NK cell populations. In the present investigation, dog mammary tumor xenograft in cyclosporine-A and gamma-irradiated, immunosuppressed Swiss Albino mice was developed and the immune cell status of graft accepted and rejected mice was assessed. It was observed that all the major immune cells (CD4+, CD8+ and NK cells) play an equal role in tumour rejection.

Voltammetric determination of cefixime in pharmaceuticals and biological fluids.

Electroreduction and adsorption of cefixime was studied in phosphate buffer by cyclic voltammetry (CV), differential pulse cathodic adsorptive stripping voltammetry (DPCAdSV), and square-wave cathodic adsorptive stripping voltammetry (SWCAdSV) at hanging mercury drop electrode (HMDE). These fully validated sensitive and reproducible cathodic adsorptive stripping voltammetric procedures were applied for the trace determination of the bulk drug in pharmaceutical formulations and in human urine. The optimal experimental parameters were as follows: accumulation potential=-0.1 V (vs. Ag/AgCl, 3M KCl), accumulation time=50s, frequency=140 Hz, pulse amplitude=0.07 V, and scan increment=10 mV in phosphate buffer (pH 2.6). The first peak current showed a linear dependence with the drug concentration over the range of 50 ng ml(-1) to 25.6 µg ml(-1). The achieved limit of detection and limit of quantitation were 3.99 and 13.3 ng ml(-1) by SWCAdSV and 7.98 and 26.6 ng ml(-1) by DPCAdSV, respectively. The procedure was applied to assay the drug in tablets. Applicability was also tested in urine samples. Peak current was linear with the drug concentration in the range of 1 to 60 µg ml(-1) of the urine, and minimum detectability was found to be 12.6 ng ml(-1) by SWCAdSV and 58.4 ng ml(-1) by DPCAdSV.

Establishment and characterization of a bovine rectal myxoma cell line.

A new bovine cell line was developed from tumor biopsy material of rectum obtained from clinical case of 7 years old cattle with tumor mass obliterating the rectal opening. Histopathology of tumor revealed scattered stellate cells arranged singly or in clusters in loose mucinous ground substance, simulating myxoma. The cells obtained from tumor mass have been cultured for more than 36 months in DMEM supplemented with 10% fetal bovine serum (FBS). The population doubling time of this cell line was about 20.64 h. The cytogenetic analysis revealed several chromosomal abnormalities with bizarre karyotype. The origin of the cell line was confirmed by PCR amplification of 1086 bp fragment of 16s rRNA using bovine species specific primers. The new cell line would act as in vitro model to study many aspect of cancer biology such as tumor development, differentiation and therapeutics regimen to combat cancer.

Adsorption of pyrantel pamoate on mercury from aqueous solutions: studies by stripping voltammetry.

Adsorption and electrochemical reduction of pyrantel pamoate are studied in Britton Robinson buffer medium at hanging mercury drop electrode (HMDE) by Adsorptive Stripping Voltammetric technique. The peak current shows a linear dependence with the drug concentration over the range 250 ng mL(-1) to 64 microg mL(-1). Applicability to assay the drug in urine samples is illustrated in the concentration range 5-20 microg mL(-1).

Cancer of the respiratory tract in nickel sinter plant workers: effect of removal from sinter plant exposure.

The risk of death due to cancer of the nose or lung was studied in nickel sinter plant workers during the period after they left the sintering operations. It was found that the excess risk of death from both diseases continued for many years after leaving the sinter plant. No effect of age at first exposure could be found. Possible explanations for the continued risk include an irreversible cellular change or the persistence of carcinogenic nickel compounds in the mucosa.

Prevalence of small opacities in chest radiographs of nickel sinter plant workers.

Radiographs from 745 nickel sinter plant workers were taken and classified by five readers using the International Labour Office (1980) protocol. Each reader worked independently and the films were randomly mixed with films from a non-dust exposed office population and also with films from subjects known to have silicosis or asbestosis. The prevalence of small irregular opacities was selected as the outcome of interest. In the sinter workers this was within the range identified in cigarette smokers or in workers exposed to dusts of low fibrogenicity. Only minimal evidence of small round opacities was noted. There was no evidence from the chest radiographs that exposures to high concentrations of dusts containing compounds of nickel caused an inflammatory or fibrogenic response in the lungs of the exposed population.

Polycyclic aromatic hydrocarbons (PAHs): a possible cause of lung cancer mortality among nickel/copper smelter and refinery workers.

A retrospective industrial hygiene investigation was undertaken to explain the cause of a statistically significant excess lung cancer mortality observed in a subset of a large cohort of nickel workers involved in mining, smelting, and refining of nickel and copper in Ontario. The focus of this paper is to demonstrate how an industrial hygiene follow-up assessment of an epidemiologic finding can help to identify a likely cause. Polycyclic aromatic hydrocarbons (PAHs) alone or in association with particulate and gaseous contaminants (e.g., SO2) were likely the causative agents of the excess lung cancer observed among the lead welders, cranemen, and arc furnace workers of the copper refinery.

Mortality of 11,500 nickel workers--extended follow up and relationship to environmental conditions.

An extended follow-up from 1977-84 was achieved in a cohort of 11,567 nickel workers engaged in mining, milling and smelting originally studied from 1950-76. Exposure data were incorporated into the analysis. One nasal cancer occurred. The lung cancer Standardized Mortality Ratio beyond 15 years from first exposure was significantly high overall (128) and in miners (153). However, detailed analyses by era of first mining and duration of mining, as well as cumulative exposure to different nickel species, did not appear consistent with an occupational etiology since significant trends were not observed. At the levels of exposure incurred, large increases in lung and nasal cancer, observed in nickel refineries elsewhere, did not occur.