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Biomedical subjects

A Kannan

Publications and source records attributed to A Kannan.

10 recordsLinked to original sources
PubMed2006

Experimental exposure of arsenic in cultured rat intestinal epithelial cells and cell line: toxicological consequences.

Arsenic is a naturally occurring metalloid and the drinking water contamination by inorganic arsenic remains a major public health problem. The trivalent arsenic (arsenite) is more toxic than the pentavalent form (arsenate), and is known to cause gastrointestinal toxicity. Specific immortal cell lines are considered to be suitable for toxicity screening and testing of chemicals as they are easy to handle and possess most of the biochemical pathways present in the corresponding cells present in vivo. The present study was designed to evaluate and compare the in vitro toxicity of arsenite on rat intestinal epithelial cell line (IEC-6) and primary cultures of rat intestinal epithelial cells (IEC). To evaluate in vitro toxicity, cultures of IEC and IEC-6 cells were assessed for viability, morphometric analysis, membrane transport enzymes and structural constituents for membrane damage, dehydrogenase activity test for respiratory and energy producing processes and esterase activity test for intra and extra cellular degradation, following the post exposures to arsenite (0-20 ppm). Significantly similar concentration-dependent changes in these toxicity-screening parameters in IEC and IEC-6 were observed. Highest tested concentration of arsenite (20 ppm) was found to be detrimental in both IEC and IEC-6. Furthermore, to evaluate arsenite toxicity in epithelial cells of rat intestine, intestinal loops were filled with arsenite solutions and incubated for 30 min in situ. In situ studies also showed a significant arsenite concentration-dependent decline in epithelial cell membrane transport enzyme activities and total hexose and sialic acid contents. Concomitant release of membrane enzymes, hexose and sialic acid in the intestinal luminal fluid following higher arsenite exposures further indicated partial membrane damage. Similar morphological changes in IEC and IEC-6 were also evident. These findings also suggest that IEC-6 cell lines are suitable for initial screening of gastrointestinal cellular toxicity caused by arsenite.

Animals↗
PubMed2006

A comparative study on rat intestinal epithelial cells and resident gut bacteria (ii) effect of arsenite.

OBJECTIVE: In order to use facultative gut bacteria as an alternate to animals for the initial gastrointestinal toxicity screening of heavy metals, a comparative study on rat intestinal epithelial cells and resident gut bacteria was undertaken. METHODS: in vitro growth rate of four gut bacteria, dehydrogenase (DHA) and esterase (EA) activity test, intestinal epithelial and bacterial cell membrane enzymes and in situ effect of arsenite were analysed. RESULTS: Growth profile of mixed resident population of gut bacteria and pure isolates of Escherichia coli, Pseudomonas sp., Lactobacillus sp., and Staphylococcus sp. revealed an arsenite (2-20 ppm) concentration-dependent inhibition. The viability pattern of epithelial cells also showed similar changes. DHA and EA tests revealed significant inhibition (40%-72%) with arsenite exposure of 5 and 10 ppm in isolated gut bacteria and epithelial cells. Decrease in membrane alkaline phosphatase and Ca2+ -Mg2+ -ATPase activities was in the range of 33%-55% in four bacteria at the arsenite exposure of 10 ppm, whereas it was 60%-65% in intestinal epithelial villus cells. in situ incubation of arsenite using intestinal loops also showed more or less similar changes in membrane enzymes of resident gut bacterial population and epithelial cells. CONCLUSION: The results indicate that facultative gut bacteria can be used as suitable in vitro model for the preliminary screening of arsenical gastrointestinal cytotoxic effects.

Animals↗
PubMed2002

Uptake of nickel (II) by Serratia marcescens.

Bioaccumulation and biosorption of various nickel salts by Serratia marcescens (NCIM 2078) were investigated Biosorption of nickel was found maximum for the nickel nitrate and nickel chloride as 28.08 and 25.51 mg-1 nickel was obtained in dry biomass of S. marcescens, respectively. The possible role of pigment prodigiosin in uptake of nickel is discussed.

Biomass↗
PubMed2001

Assessment of physiological stress in periparturient cows and neonatal calves.

Pregnancy is considered to be one of the physiological stressors. The stress hormone, cortisol is significantly involved in various events during periparturient period including initiation of parturition. The study was conducted to estimate the serum cortisol concentration in cows and the neonatal calves in order to correlate the effect of cortisol on certain haematological and biochemical parameters such as blood glucose level (BGL), total plasma protein (TPP), lymphocyte:neutrophil ratio and mitogen induced lymphocyte proliferative response. Blood samples were collected from six cows in four periods, namely., 3 days prior to parturition, on the day of parturition, and 7 days after parturition. Blood samples were also collected from neonatal calves in the period 0, 7 and 14 days of age. Calves above two months of age and non-pregnant dry cows were considered as the controls. The serum cortisol concentration in cows on the day of parturition was significantly higher (P < 0.01) than controls and the value in calves was also significantly higher (P < 0.01) at 0 day than their controls. On the day of parturition BGL level of the dam and calves were significantly higher (P < 0.01), whereas the proliferative response of lymphocytes to mitogen was significantly lower (P < 0.01) than controls. However TPP levels did not differ significantly. This confirmed that the dam at the time of parturition and neonatal calf before taking colostrum are under a high risk of infection because of the low profile of immune status. The lymphocyte:neutrophil ratio also justified the above suggestion.

Animals↗
PubMed2000

Effect of betel/areca nut (Areca catechu) extracts on intestinal epithelial cell lining.

Carcinogenic and other toxic manifestations of areca/betel nut extracts on the buccal cavity and upper digestive tract are well documented. The present study deals with in vivo and in situ effects of aqueous and alcoholic extracts of areca nut on rat intestinal epithelial cell membrane. In vivo daily oral administration by gastric intubation for 1p w produced significant declines in brush border membrane alkaline phosphatase, Ca2+-Mg2+-ATPase, and the digestive enzyme sucrase. The decline in activities were more prominent after 4-w exposures. Instant short term in situ exposure to aqueous extract produced higher enzyme activities, indicating the initial activation of active sites by areca nut extract constituent(s). Significant declines in brush border membrane constituents (total hexose, sialic acid and cholesterol) were also evident following continuous exposures to areca nut extracts. These findings suggest that prolonged chewing of areca nut causes significant alterations in intestinal epithelial cell lining functions and could lead to malabsorption of nutrients.

Administration, Oral↗
PubMed1999

Assessment and treatment of dental caries in semi-urban school children of Tamilnadu (India).

The study was carried out with the purpose of evaluating the prevalence of dental caries, in semi urban school children. The sample comprised of 415 school going children. DMFT/dmft scores were recorded as per WHO 1987 criteria. Mean DMFT was found to be 0.17, 0.06 in male and female children at 3 to 6 age group which increased to 1.21 & 1.10 in males and female in 9 to 12 year age group. Mean dmft at 3 to 6 years was 1.36, 1.17 in male and female children which further increased at 6 to 9 years in both sexes but in the 9 to 12 year age group the value decreased to 1.48, 0.87 in male and female children respectively. The entire sample showed a dental caries prevalence of 58.1. It was noted that the children brushed once a day with toothpaste and toothbrush. Complete oral rehabilitation was undertaken through an incremental school health care programme.

Age Distribution↗
PubMed1984

Determination of C lambda for a graphite-walled reference ionization chamber.

A method of evaluation of chamber wall dependent components Am, Aeq and alpha of the absorbed dose conversion factor C lambda, for a graphite wall reference ion chamber is described in this paper. The procedure of utilising such a reference chamber for routine absorbed calibration of commercial dosemeters at high photon energies is also described.

Graphite↗
PubMedDate not supplied

Estimation of menthol in Pan Masala samples by a spectrophotometric method.

Recently, the Prevention of Food Adulteration Act of India has fixed the level of menthol addition to Pan Masala at 0.1%, therefore good manufacturing practice (GMP) should be adopted so that the samples do not exceed 0.1% menthol (1 mg/g). The estimation of menthol in Pan Masala samples involves steam distillation followed by reaction with p-dimethyl amino benzaldehyde (DMAB) in acidic medium to give a red colour which is read at 550 nm. The sensitivity of this procedure is 75 micrograms menthol per g sample. Using this method, 130 branded and 53 non-branded samples of Pan Masala were analysed for menthol content. Almost 25% of branded samples contained less than 1 mg menthol per g while 75% of samples contained 1.1-6.5 mg menthol per g Pan Masala. Non-branded Pan Masala contained 1 mg menthol per g in only 7.6% of samples. However, 92% of samples contained 1.1-6.5 mg menthol per g, suggesting that the addition of menthol is relatively higher in non-branded Pan Masala samples than in branded ones.

Areca↗
PubMedDate not supplied

An outbreak of food poisoning in a workers' camp in Saudi Arabia caused by Salmonella minnesota.

Between 13 and 16 September 1985, 168 of 419 Filipino workers, living in a camp near Dammam, Saudi Arabia, developed acute gastroenteritis with diarrhoea, vomiting, abdominal pain, and low-grade fever. The outbreak was confined to those who ate from a single kitchen. The median approximate incubation period of the disease was 34 hours (range 8 to 96 hours). Salmonella minnesota was isolated from the stools and rectal swabs of 34% of the patients. One of the 27 cooks was positive for the organism. There was no infection diagnosed among 390 close contacts of the patients, and the organism was also not grown from samples of leftover or fresh food. All isolates were sensitive to most of the commonly used antimicrobials, except tetracycline and streptomycin. A particular meal served from a single kitchen was tentatively implicated as the source of the outbreak.

Diarrhea↗