Search tips
Search criteria

Results 1-4 (4)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
Document Types
1.  PCB153 reduces Telomerase Activity and Telomere Length in Immortalized Human Skin Kerantinocytes (HaCaT) but not in Human Foreskin Keratinocytes (NFK) 
Toxicology and Applied Pharmacology  2011;259(1):115-123.
Polychlorinated Biphenyls (PCBs), ubiquitous environmental pollutants, are characterized by long term-persistence in the environment, bioaccumulation, and biomagnification in the food chain. Exposure to PCBs may cause various diseases, affecting many cellular processes. Deregulation of the telomerase and the telomere complex leads to several biological disorders. We investigated the hypothesis that PCB153 modulates telomerase activity, telomeres and reactive oxygen species resulting in the deregulation of cell growth. Exponentially growing immortal human skin keratinocytes (HaCaT) and normal human foreskin keratinocytes (NFK) were incubated with PCB153 for 48 and 24 days, respectively, and telomerase activity, telomere length, superoxide level, cell growth, and cell cycle distribution were determined. In HaCaT cells exposure to PCB153 significantly reduced telomerase activity, telomere length, cell growth and increased intracellular superoxide levels from day 6 to day 48, suggesting that superoxide may be one of the factors regulating telomerase activity, telomere length and cell growth compared to untreated control cells. Results with NFK cells showed no shortening of telomere length but reduced cell growth and increased superoxide levels in PCB153-treated cells compared to untreated controls. As expected, basal levels of telomerase activity were almost undetectable, which made a quantitative comparison of treated and control groups impossible. The significant down regulation of telomerase activity and reduction of telomere length by PCB153 in HaCaT cells suggest that any cell type with significant telomerase activity, like stem cells, may be at risk of premature telomere shortening with potential adverse health effects for the affected organism.
PMCID: PMC3288560  PMID: 22210444
polychlorinated biphenyls (PCBs); telomere; telomerase; superoxide; cell growth; skin keratinocytes
2.  Airborne polychlorinated biphenyls (PCBs) reduce telomerase activity and shorten telomere length in immortal human skin keratinocytes (HaCat) 
Toxicology letters  2011;204(1):64-70.
PCBs, a group of 209 individual congeners, are ubiquitous environmental pollutants and classified as probable human carcinogens. One major route of exposure is by inhalation of these industrial compounds, possibly daily from inner city air and/or indoor air in contaminated buildings. Hallmarks of aging and carcinogenesis are changes in telomere length and telomerase activity. We hypothesize that semi-volatile PCBs, like those found in inner city air, are capable of disrupting telomerase activity and altering telomere length. To explore this possibility, we exposed human skin keratinocytes to a synthetic Chicago Airborne Mixture (CAM) of PCBs, or the prominent airborne PCB congeners, PCB28 or PCB52 for up to 48 days and determined telomerase activity, telomere length, cell proliferation, and cell cycle distribution. PCBs 28, 52 and CAM significantly reduced telomerase activity from days 18–48. Telomere length was shortened by PCB52 from day 18 and PCB28 and CAM from days 30 on. All PCBs decreased cell proliferation from day 18; only PCB52 produced a small increase of cells in G0/G1 of the cell cycle. This significant inhibition of telomerase activity and reduction of telomere length by PCB congeners suggest a potential mechanism by which these compounds could lead to accelerated aging and cancer.
PMCID: PMC3109099  PMID: 21530622
polychlorinated biphenyls (PCB); telomere; telomerase; cell cycle; air pollution; mixture
3.  In Vitro Organogenesis of Lycianthes bigeminata Bitter 
Ancient Science of Life  2007;26(4):18-23.
Lycianthes bigeminata Bitter (Solanaceae) is an important medicinal herb distributed in the sholas of Nilgiris and chiefly used for curing ulcer. It is reported that the species is present in the sholas with poor population size in comparison to other constituent species. Owing to the demand and subsequent exploitation, it is predicted that it may occupy still poor association in the sholas of Nilgiris in course of time. Hence in vitro regeneration through employing tissue culture technique is needed. The preliminary attempt in the present study reports that the MS medium supplemented with Benzyl Amino Purine (BAP) and Naphthalene Amino Acid (NAA) at 0.5 mg/l each, induced effective callus formation. However further studies on hardening is suggested to know the survivability of this species.
PMCID: PMC3330881  PMID: 22557245
Lycianthes bigeminata; callus; in vitro organogenesis
4.  Nature, prevalence and factors associated with depression among the elderly in a rural south Indian community 
Background: Depression in old age is an important public health problem causing considerable morbidity and disability worldwide. There is a dearth of community studies from India investigating geriatric depression and its associated risk factors. This study aimed to establish the nature, prevalence and factors associated with geriatric depression in a rural south Indian community.
Methods: We recruited 1000 participants aged over 65 years from Kaniyambadi block, Vellore, India. We assessed their socio-demographic profile, psychiatric morbidity, cognitive functioning, anthropometrics and disability status using the following structured assessment tools: Geriatric Mental State, Community Screening Instrument for Dementia, Modified CERAD 10 word list learning task, History and Aetiology Schedule Dementia Diagnosis and Subtype, WHO Disability Assessment Scale II, and Neuropsychiatric Inventory. We adopted a case control framework to study the factors associated with geriatric depression.
Results: Prevalence of geriatric depression (ICD-10) within the previous one month was 12.7% (95% CI 10.64–14.76%). Low income (OR 1.78; 95% CI 1.08–2.91), experiencing hunger (OR 2.58; 95% CI 1.56–4.26), history of cardiac illnesses (OR 4.75; 95% CI 1.96–11.52), transient ischemic attack (OR 2.43; 95% CI 1.17–5.05), past head injury (OR 2.70; 95% CI 1.36–5.36) and diabetes (OR 2.33; 95% CI 1.15–4.72) increased the risk for geriatric depression after adjusting for other determinants using conditional logistic regression. Having more confidants (OR 0.13; 95% CI 0.06–0.26) was the significant protective factor. Age, female gender, cognitive impairment and disability status were not significantly associated with geriatric depression. DSM-IV diagnosis of major depression was significantly correlated with experiencing hunger, diabetes, transient ischemic attack, past head injury, more disability and less nourishment; having more friends was protective.
Conclusions: Geriatric depression is prevalent in rural south India. Poverty and physical ill health are risk factors for depression among elderly while good social support is protective.
PMCID: PMC3100909  PMID: 19243657
depression; dementia; risk factors; poverty; social supports

Results 1-4 (4)