Parthasarathy chenna Kesavan

Bhabha Atomic Research Centre | BARC · Radiology Unit

In the hierarchy of human needs, food is absolutely the most basic. As the human population was increasing at an accelerated rate with concomitant depletion of natural resources during the 18th century, Malthus was greatly concerned about the sustainability of food availability. Despite the fact that the human population has been burgeoning, a tota...

While the M.S. Swaminathan Research Foundation (MSSRF) has been developing and refining ecofriendly and socially inclusive strategies to achieve a 'zero hunger' India, the 'Voluntary Health Service' (VHS) in the neighbourhood of MSSRF has been focusing on providing quality health care to patients who are too poor to get medical treatment as those w...

The evergreen revolution aims at achieving productivity in perpetuity without accompanying ecological and social harm. The smallholder family farms with pro-nature, pro-poor and pro-women orientation provide a boost to the evergreen revolution. Revitalization of family farming traditions with emphasis on the empowerment of women and youth will enha...

The green revolution of the 1960s and 1970s which resulted in dramatic yield increases in the developing Asian countries is now showing signs of fatigue in productivity gains. Intensive agriculture practiced without adherence to the scientific principles and ecological aspects has led to loss of soil health, and depletion of freshwater resources an...

The evergreen revolution aims at achieving productivity in perpetuity without accompanying ecological and social harm. The smallholder family farms with pro-nature, pro-poor and pro-women orientation provide a boost to the evergreen revolution. Revitalization of family farming traditions with emphasis on the empowerment of women and youth will enha...

Human-induced changes in climate will have both common and differentiated impacts. It is now widely accepted that the average mean temperature will increase by 1 to 2°C during this century. Such an increase in temperature will reduce the duration of crops like wheat and thereby reduce yield in Northern India. In contrast, a rise in mean temperature...

The green revolution of the 1960s and 1970s which resulted in dramatic yield increases in the developing Asian countries is now showing signs of fatigue in productivity gains. Intensive agriculture practiced without adherence to the scientific principles and ecological aspects has led to loss of soil health, and depletion of freshwater resources an...

Extreme natural disasters, particularly those induced by hydro-meteorological factors are not only becoming more frequent, but their destructive potential is also increasing. Population explosion and global warming are enhancing their adverse effect and hence, strengthening the coping capacity to natural disasters is of particular concern to coasta...

Extreme natural hazards, particularly the hydro-meteorological disasters, are emerging as a cause of major concern in the coastal regions of India and a few other developing countries. These have become more frequent in the recent past, and are taking a heavy toll of life and livelihoods. Low level of technology development in the rural areas toget...

The 'hit theory' developed in 1920s to explain the actions of ionizing radiation on cells and organisms was purely physical, and its limitation was its inadequacy to address the contemporary findings such as the oxygen enhancement of radiobiological damage, and the increased radiosensitivity of dividing compared to non-dividing cells. The textbooks...

One of the many areas of research initiated by Swaminathan at the Botany Division of the Indian Agricultural Research Institute, New Delhi was radiation cytogenetics, which involves study of induced chromosomal aberrations. These studies had impact not only on elucidating basic mechanisms involved in the formation of chromosomal aberrations, but al...

Electron paramagnetic resonance (EPR) studies were conducted on barley seeds exposed to normal (H(2)O) and deuterated (D(2)O) moisture, irradiated with 750 Gy at 77 K. Reported here, for the first time, are the trapped electrons formed on gamma-irradiation of seeds at 77 K. Electrons are stabilized/solvated with an increase in the moisture content...

Electron paramagnetic resonance (EPR) studies were conducted on barley seeds exposed to normal (H20) and deuterated (D2O) moisture, irradiated with 750 Gy at 77 K. Reported here, for the first time, are the trapped electrons formed on γ-irradiation of seeds at 77 K. Electrons are stabilized/ solvated with an increase in the moisture content (H2O/D2...

Caffeine (1,3,7-trimethyl xanthine), a dietary component, has been shown to have widely varying effects on DNA damage induced by UV and ionizing radiation, depending upon pre- or post-irradiation administration and its concentration. Caffeine administered post-UV irradiation is known to inhibit enzymatic repair of DNA lesions, leading to potentiati...

The question of whether very small doses of ionizing radiation really exert stochastic effects (i.e. induce harmful genetic effects, including cancer in a probablistic manner) has not been unequivocally settled. The much relied upon linear, no-threshold (LNT) hypothesis does not have convincing experi- mental evidence. As there are practical diffic...

Following the demonstration that caffeine effectively competes with oxygen for electrons and also scavenges hydroxyl radicals and singlet oxygen, the differential modification of oxygen-dependent and independent effects of gamma-radiation by caffeine in membranes was examined, using rat liver mitochondria as a model system. Mitochondria were isolat...

Radiation is one of the physical agents that induce oxidative stress. Exposure of rat liver mitochondria to high doses of 60Co γ-rays (45-600 Gy) results in the loss of activity of superoxide dismutase (SOD). Presence of caffeine, even in micromolar amounts, during exposure prevents loss of SOD activity. Caffeine, at a concentration of 1 mM also sh...

Administration of caffeine (1,3,7-trimethylxanthine), a major component of coffee, to Swiss mice at doses of 80 or 100 mg/kg body weight 60 min prior to whole-body lethal dose of gamma-irradiation (7.5 Gy) resulted in the survival of 70 and 63% of animals, respectively, at the above doses in contrast to absolutely no survivors (LD-100/25 days) in t...

Antigenotoxic effects and changes in glutathione S-transferase (GST) activity were assessed in mice after oral co-administration of urethane (URE) with aqueous extracts of dietary vegetables (carrot, spinach and cabbage), spices (cinnamon, pepper, cumin, clove and cardamom), tea and coffee. The results of the genotoxicity assay (micronucleus test)...

Cysteine (an aminothiol) is known to protect against radiation damage, and is understood to do so by generating hydrogen peroxide which subsequently inhibits RNA synthesis. Our results showed inability of catalase to remove or reduce the magnitude of radioprotection by caffeine and/or cysteine at optimal/suboptimal temperatures in barley. This obse...

Freshly prepared aqueous extract of garlic was tested in mice for its possible in vivo protective effect against gamma-radiation-induced chromosomal damage. In the same animals, the changes in the sulphydryl content and glutathione S-transferase activity were evaluated. Three doses of garlic extract [125, 250 and 500 mg kg-1 body weight (bw)] were...

Caffeine (1,3,7-trimethyl xanthine), an ingredient of coffee, has been investigated for its potential antioxidant activity against oxidative damage to rat liver microsomes. Such damage was induced by three reactive oxygen species of cardinal importance in causing membrane damage in vivo namely hydroxyl radical (.OH), peroxyl radical (ROO.) and sing...

Caffeine, a major constituent of coffee and other beverages has significant abilities to scavenge highly reactive free radicals and excited states of oxygen and to protect crucial biological molecules against these species. This is one of the possible reasons why caffeine acts as a radioprotector against oxygen-dependent ('oxic') pathway of radiati...

The effect of pretreatment with buthionine sulphoximine (BSO) on the radiosensitivity of mouse bone marrow cells was studied using the in vivo micronucleus test. Varying concentrations of BSO were injected into mice by intraperitoneal injection 2 h before irradiation, and the frequency of micronuclei in polychromatic erythrocytes (MnPCEs) of bone m...

Buthionine sulfoximine (BSO) enhances the radiosensitivity of in vitro mammalian cells, possibly by inhibiting de novo biosynthesis of glutathione (GSH); however, administration of BSO to intact animals results in no effect or possibly radioprotection. Keeping in view that BSO affords radioprotection its physico-chemical action in dry (metabolicall...

When considering modification of radiobiological damage by any physical or chemical agent, it is necessary to keep in view the role of molecular oxygen present during irradiation of cells and organisms. It has been known for a long time that the yield of mutations and chromosomal aberrations and other effects such as cell killing, can be considerab...

Garlic extract was evaluated in the mouse bone marrow micronucleus test for its possible protective effects against gamma-radiation-induced chromosomal damage. Together with this, biochemical assays were carried out to determine the changes in sulfhydryl content and glutathione S-transferase activities. Three doses of freshly prepared garlic extrac...

Oral administration of an algal mutant C. vulgaris E-25, 1 hr before or immediately after exposure to sublethal gamma-rays increased the number of endogenous spleen colony forming units (E-CFU). The magnitude of radioprotection was dependent on both, the dose of C. vulgaris fed and the time of administration. An optimal E-CFU was observed when 500...

Chlorophyllin was evaluated in the mouse bone marrow micronucleus test for its possible protective effects against chromosomal damage induced by gamma-radiation, cyclophosphamide, N-nitroso-N-ethylurea and urethane. Three doses of chlorophyllin (50, 100 and 200 mg/kg, b.w.) were orally administered to mice 2 h before exposure to the clastogens unde...

The possible role of orally fed Chlorella vulgaris (E-25) in modulating the gamma-ray induced chromosomal damage in whole-body irradiated mice was evaluated using a micronucleus test. Different doses of E-25 were administered either chronically (once, twice or thrice a day for 28 days) or as single acute doses before/after irradiation. A significan...

The mouse bone marrow micronucleus test was carried out to evaluate the possible role of the dietary constituents chlorogenic acid (CGA), curcumin (CR) and beta-carotene (BC) in modulating the in vivo chromosomal damage induced by gamma-radiation. The results obtained suggest that oral administration of CGA (50, 100 and 200 mg/kg b.w.), CR (5, 10 a...

The effects of vitamins C and E on bone marrow chromosomes of the mouse exposed to 1 Gy of whole-body gamma-irradiation were studied. These vitamins, dissolved in water/peanut oil, were administered orally as acute doses, either 2 h before, immediately after, or 2 h after irradiation. Both vitamins significantly reduced the frequencies of micronucl...

Using bone marrow cells of whole body irradiated mice, the cytogenetic adaptive response induced by low conditioning doses of gamma-rays was investigated. The conditioning doses (0.025 and 0.05 Gy) were given at a dose-rate of 1.67 Gy/min. The challenging dose of 1 Gy was given at a dose-rate of 0.045 Gy/s. The challenging dose was given at differe...

Dry barley seeds were exposed to 60Co gamma-rays in vacuo and post-hydrated at 4 degrees C for 8 h in O2, N2 or N2O-saturated water. Post-irradiation damage was assessed in terms of seedling injury and peroxidase activity in the 8 day-old seedlings. Both cysteine (CySH) and glutathione (GSH) afford significant radioprotection against O2-dependent d...

Experiments were carried out to investigate whether or not depletion of the glutathione (GSH) level in Drosophila melanogaster larvae with buthionine sulfoximine (BSO) treatment can result in the modulation of the frequency of sex-linked recessive lethal (SLRL) mutations induced by gamma-radiation. Third instar larvae were fed on BSO for 24 h befor...

The effect of caffeine given as pre- and post-treatment in mice exposed to whole-body gamma-irradiation (1.5 Gy 60Co gamma-rays) was studied. The pre-treatment was either acute or chronic. The acute dose (5 mg/kg and 15 mg/kg body weight) was in the form of an injection given intraperitoneally, 30 min before irradiation. The chronic administration...

Wet heat shock (60 degrees C, 90 s) and caffeine (3.8 X 10(-4) M) afford significant radioprotection against post-irradiation O2-dependent damage which develops in seeds of approximately 3.5% moisture content. The damage was assessed in terms of seedling injury on the eighth day of growth. An increase in seedling injury is clearly seen, associated...

The influence of ascorbic acid, potassium permanganate and caffeine on the postirradiation seedling injury of dry barley seeds was studied, irradiated (350 Gy 60Co gamma-rays) in vacuo and post-hydrated with varying oxygen concentrations in the soaking medium. The oxygen concentration in the post-hydration medium (OCHG) was adjusted at 0%, 10%, 30%...

Dry (approximately 3.5 and 4.0 per cent moisture content) barley seeds were exposed to 350 Gy of 60Co- gamma-rays in vacuo and post-hydrated at 4 degrees C for 8 h in O2-, N2-, or N2O-saturated water. The effect of caffeine and t-butyl alcohol (t-BuOH) dissolved in the post-hydration medium on the magnitude of damage developing under these three di...

If H2O2 is one of the major mediators of the 'oxygen effect' in biological systems then catalase, which enzymically decomposes H2O2 should have a significant influence on radiation damage, particularly under oxygenated conditions. The post-irradiation (300 Gy gamma rays) effect of catalase was, therefore, assessed on barley seeds of about 4 per cen...

Studies were carried out on the effect of caffeine on the X-irradiation sensitivity of B. megaterium spores with the following results: Caffeine exerts a concentration-dependent modifying action on oxygen-dependent components of X-ray-induced damage in B. megaterium spore suspensions causing an 'over-O2 effect' at about 1 X 10(-4) mol dm-3, and as...

Data on the differential modification of the oxic and anoxic components of radiation clastogenesis by caffeine already published in the literature have been briefly reviewed, additional unpublished data relevant for consideration of possible mechanisms have been presented and the possible events in terms of radiation chemistry have been discussed....

The genotoxic effects of orally administered garlic and turmeric were evaluated in bone-marrow cells of mice by performing the micronucleus test. Another spice, asafoetida, was tested for the induction of sister-chromatid exchanges (SCEs) in spermatogonia of mice. Results of the micronucleus test with garlic and turmeric were not significantly diff...

The "carcinogenic" betel nut and constituents of betel quid were tested for possible mutagenicity in Drosophila. The test compounds were administered either alone or in combinations by larval feeding. The data on sex-chromosome loss, sex-linked recessive lethals and autosomal translocations suggest lack of mutagenicity.

La cystine est un radio-protecteur plus efficace que la cafine contre le dommage post-irradiatoire d l'oxygne. Mais la cystine n'exerce aucune influence sur la partie du dommage qui ne dpend pas de l'oxygne et la cafine accentue ce dommage. Dans le traitement simultan de cafine et de cystine, c'est seulement la cafine qui dtermine l'amplitude et le...

Tandis que l'emploi de cafine avant l'irradiation tend augmenter le dommage fait aux chromosomes, l'application de cystine immdiatement aprs l'irradiation diminue ce dommage. Par consquent, un traitement de cafine avant et de cystine aprs l'irradiation offre le maximum de protection.

The modification of radiosensitivity of barley seeds with 11·1 per cent water content by caffeine and cysteine applied during oxygenated and oxygen-free hydration was studied. No post-irradiation oxygen-dependent damage develops in these seeds. While cysteine has no influence at all, caffeine effectively potentiates the level of the gamma-induced o...

The lethal effects of both ionizing and non-ionizing radiations have many potentially important applications in food technology. To capitalize on this use, a pre-requisite is the clear establishment of the absence of undesirable secondary effects in the irradiated material. Commencing from the study of Stone, Wyss and Haas(150) who found that U.V.-...

The cytotoxic activity of gamma irradiated sucrose solution (5%) was found to inhibit significantly the eight-day growth of roots and shoots of barley seedlings and also induce chromosomal aberrations in the root tip cells of Vicia faba. Irradiated water exhibited little or no such cytotoxic activity, presumably due to the lack of formation of long...

Livestock are vital to subsistence farming and sustainable livelihood in most developing countries. Of India’s population of one billion people, more than 70 percent live in the rural areas. India also has more than 30 percent of the world’s bovine population. This has resulted in not only egalitarian ownership of cattle, but also in an almost inse...

The effects of sucrose irradiated with 0·5 to 3 Mrad of γ-rays and stored for different durations were studied in Tropaeolum majus, using the germination and tube growth of pollen as indices. The extent of the inhibitory effect increased with dosage and was either enhanced or reduced with storage depending upon the initial dose. It appears possible...