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Biomedical subjects

B K Patnaik

Publications and source records attributed to B K Patnaik.

At least 19 recordsLinked to original sources
PubMed2000

Effect of age on lipid peroxides, lipofuscin and ascorbic acid contents of the lungs of male garden lizard.

Oxidative damage was assessed through the estimation of lipid peroxides (LP) in the lungs of an ageing short-lived species of reptile, Calotes versicolor, commonly known as the garden lizard. Attempts were also made to trace its relationship with the age pigment, lipofuscin and the antioxidant ascorbic acid. While LP increased with advancing age the contents of both lipofuscin and ascorbic acid did not show appreciable change during maturation ( < 1-1 year old) but declined during senescence phase (1 to 2-4 year old). While the pattern of age associated changes in LP and ascorbic acid indicate similarity with the pattern observed in most of the mammals, the reduction of lipofuscin in older lizards is a significant departure from the common trend.

Aging↗
PubMed1999

Effects of age and manganese (II) chloride on peroxidase activity of brain and liver of the teleost, Channa punctatus.

Fish provide enormous spectrum of longevity and thus present the possibility of multiple mechanisms of senescence. Oxidative stress as a causative agent of senescence and the protective role of antioxidant enzymes were tested in the teleost, Channa punctatus taking peroxidase (POD) (EC 1.1 1.1.7) as the representative enzyme. The activity of POD in brain and liver declined during maturation phase (young vs middle-aged). During senescence phase (middle-aged to old) the enzyme activity increased in liver but remained stabilized in brain. The degree of increase in peroxidase activity following in vitro MnCl2 treatment was always higher in liver than in brain. The rate of MnCl2 induced increase in POD activity of both tissues showed an increasing trend with age. However statistical significance was observed only in brain during senescence phase. No significant loss of enzyme activity in both the tissues and greater degree of increase by MnCl2 in brain suggest that antioxidant capacity is not impaired in old murrels.

Aging↗
PubMed1994

Ageing in fishes.

Fishes show three types of senescence. Lampreys, eels and pacific salmon exhibit rapid senescence and sudden death at first spawning. The guppy, red panchax, medaka, platyfish, Indian murrel and many other teleosts undergo gradual senescence, as observed in most of the vertebrates. A number of fishes (e.g. sturgeons, paddlefish, female plaice, flatfish, rockfish) show indeterminate growth, the occurrence of senescence in them is supposed to be very slow or negligible. Neuroendocrine mechanisms are involved in rapid senescence. Most of the evidences in favour of the occurrence of senescence in fishes have been derived from studies in species showing gradual senescence. Age-related increases in mortality rate, accumulation of lipofuscin, lipid peroxidation, collagen cross-linking and decreases in growth rate, reproductive capacity and protein utilisation are clearly marked in such species. Anatomical changes in various organs during ageing also confirm increases in degenerative changes and pathological symptoms. Dietary restriction and lower environmental temperature retard the ageing processes in a few species showing gradual senescence. These results tentatively support the contention of commonality in mechanism of ageing processes in vertebrates. At present, anatomical, cellular, biochemical and genetic evidences in support or against the occurrence of slow senescence or negligible senescence in long-lived fish species are almost nonexistent. Extensive studies on ageing in fishes are needed to explain the multiple mechanisms which are not unexpected considering the number and variety of the existing species.

Aging↗
PubMed1994

Ageing in reptiles.

Like in fishes, the reptiles appear to show three types of senescence. The African skink, Mabuya buettneri, shows rapid senescence similar to death at mating observed in Salmon and marsupial mouse. Most of the lizards and snakes undergo gradual senescence comparable to the pattern exhibited by a majority of vertebrates. On the other hand, turtles, tortoises and crocodiles continue to grow throughout life and are thus credited with slow or negligible senescence. Evidences and mechanisms of rapid or negligible senescence in reptiles are still fragmentary and unclear. Findings in a few species of lizards (Calotes versicolor) and snakes (Natrix natrix) showing gradual senescence support the concept of commonalities in ageing phenomena in vertebrates. An age-related increase in the stability of collagen and accumulation of altered enzyme molecules, a decrease in metabolism and response to stress-enhanced anti-oxidative defence mechanisms and the nature of responses to hormones, restricted diet and lower environmental temperature corroborate the concept. On the other hand neither the increase in mortality rate and accumulation of lipofuscin nor the reproductive senility have been shown conclusively in ageing reptile populations. It is likely that there are multiple mechanisms of senescence in reptiles. Further studies on selected species from among the 6,000 living species are necessary to unravel the phenomena.

Aging↗
PubMed1993

Age-dependent changes in some aspects of glutamate metabolism in the brain of the teleost, Channa punctatus. I. Ammonia and glutamine contents and glutamate dehydrogenase activity.

Age related changes in some aspects of glutamate metabolism were followed in the brain of a short lived species of tropical murrel, Channa punctatus. Both ammonia and glutamine contents of brain increased with advancing age of the murrel. The glutamate dehydrogenase activity of brain increased during maturation phase (year classes 0(+)-3+) followed by a decline in senescence phase (year classes 3(+)-6+). The pattern of age changes in glutamate metabolism in this species of fish shows similarity with the observations made in a majority of mammalian species, thereby suggesting a commonality in a basic metabolic mechanism during aging process in the central nervous system of vertebrates.

Aging↗
PubMed1992

Changes in catalase activity and its thermolability in liver and kidneys of ageing male garden lizard.

Catalase activity in liver and kidneys of male garden lizards remained unchanged during maturation, but showed an increase during ageing. Instead of inactivating catalase, thermal treatment at 60 +/- 1 degree C caused a marginal increase in enzyme activity in the liver of middle-aged and kidneys of young lizards with no significant effect in old counterparts. Increase in basal enzyme activity during ageing and the maintenance of resistance against thermal inactivation of the enzyme throughout the life-span support the contention that catalase molecules in lizard tissues are not altered as a function of age, a deviation from the predictions of Orgel's error catastrophe hypothesis.

Aging↗
PubMed1991

Effect of age on thermal inactivation of glucose-6-phosphate dehydrogenase in liver and kidney of the male garden lizard.

A comparison between middle-aged and old lizards revealed no significant age change in glucose-6-phosphate dehydrogenase activity of liver and kidney. Thermal inactivation at 51 +/- 1 degree C induced a significantly higher degree of decline in enzyme activity of tissues of old than that of middle-aged lizards. The increase in thermolability of enzyme in liver and kidney of ageing lizards suggests an accumulation of altered enzyme molecules.

Aging↗
PubMed1990

Effect of malonate and p-chlorophenoxy acetic acid on hepatic succinic dehydrogenase activity of ageing lizards.

The degree of inhibition of hepatic succinic dehydrogenase activity by malonate, a competitive inhibitor, did not differ between young and middle-aged lizards. On the other hand, the same parameter increased significantly between middle-aged and old lizards. The percent inhibition of enzyme activity by p-chlorophenoxy acetic acid was also age-dependent, being higher in middle-aged and old than in young lizards.

Aging↗
PubMed1989

Effect of thyroxine (T4) and thiourea on the hepatic oxygen consumption of male garden lizards of three different age groups.

Administration of T4 (1 microgram/g body-weight on alternate days) to male garden lizards of three different age groups (young, middle-aged and old) for a period of 2 weeks caused a significant rise in the hepatic oxygen consumption, the degree of response increasing with advancing age. On the other hand, when treated in vitro (5 micrograms T4 in the medium) the stimulation of hepatic oxygen consumption was observed only in lizards of the young age group. Oral administration of thiourea (0.05 mg/g body-weight on alternate days, three doses) led to a decrease in hepatic oxygen uptake, the degree of inhibition being higher in young (30%) and old (28%) than in middle-aged lizards (12%).

Aging↗
PubMed1988

Age-related changes in the response of hepatic succinic dehydrogenase activity to thyroxine and thiourea in lizards.

Intraperitoneal injection of thyroxine (T4; 1 microgram/g body weight on alternate days, seven doses) to male garden lizards of three different age groups caused a stimulation of hepatic succinic dehydrogenase activity, the degree of response being higher in the old (63%) than in middle-aged (39%) and young (31%). Percent inhibition of enzyme activity following thiourea treatment (0.05 mg/g body weight on alternate days, three doses) was higher in middle-aged lizards (24%) than in young (10%) and old (12%) ones.

Age Factors↗
PubMed1985

Age-related differences in the response of hepatic oxygen consumption to thermal stress in the male garden lizard.

The main aim of the present study is to compare the thermal adaptation capacity of young, middle-aged and old lizards with respect to hepatic oxygen consumption. Cold exposure (1 h at 0-4 degrees C) caused a decline in endogenous oxygen consumption in young but did not evoke significant changes in middle-aged and old lizards. On the other hand, with 5 mM succinate the rate of respiration increased marginally only in cold-exposed old lizards. This suggests that the metabolic response to cold is age-dependent in these lizards. Exposure of homogenates at 40 +/- 1 degree C for 15 min led to a rise in the hepatic oxygen consumption of young but not in that of either middle-aged or old lizards. There were no changes in the rate of oxygen consumption upon exposure for a similar period at 45 +/- 1 degree C of liver homogenates from lizards of three different age groups. However, exposure at 51 +/- 1 degree C resulted in a higher degree of decline in the rate of hepatic oxygen consumption in middle-aged and old than in young lizards. Thus, the young lizards appear to be better-adapted to hyperthermic stress than the middle-aged and old.

Adaptation, Physiological↗
PubMed1984

Changes in morphometric parameters and the characteristics of collagen following thyroxine and thiourea treatments in young male garden lizards.

Administration of both thyroxine (1 microgram/g body wt) and thiourea (0.5 mg/10 g body wt) to young male garden lizards for a period of 2 weeks led to changes in morphometric/biochemical parameters. Percentages of increase in body weight and snout-to-vent length of thyroxine-treated lizards during this period were significantly lower than the percentages of increase observed in control lizards. Thiourea-induced inhibition of increase in body weight was marginal but not significant statistically. The total collagen content of tendons decreased upon thyroxine treatment and increased following thiourea administration. Thyroxine treatment led to an increase in salt solubility of bone and skin collagens and thiourea showed a reverse effect. On the other hand, the acid solubility of tendon collagen increased after thyroxine administration and decreased following thiourea treatment.

Aging↗
PubMed1984

Thyroid hormones and carbohydrate metabolism of brain in the teleost, Channa punctatus. I. Effect of T4 and thiourea on succinic dehydrogenase (SDH) activity and protein content.

The brain of the fishes (Channa punctatus) subjected to cold acclimation (15 +/- 1 degree) in darkness exhibited low succinic dehydrogenase (SDH) activity after 3 and 7 days and high protein content after 7 days when compared with their warm acclimated (32 +/- 1 degree) counterparts. In warm acclimated fishes maintained in complete darkness, T4 (0.5 micrograms/g body weight/day) depressed the enzyme activity after 5 and 7 days of treatment and reduced the protein content after 3 days. But neither in cold acclimated fishes maintained in darkness for 3, 5, and 7 days nor in warm acclimated fishes maintained in 12 hr dark and 12 hr daylight for the same periods did T4 induce a significant change in the same biochemical parameters. It appears that T4 action in this fish is dependent on acclimation temperature and light:dark regimes. When warm acclimated control fishes maintained in complete darkness were compared with those maintained in 12 hr dark and 12 hr daylight, the enzyme activity was found to be higher and the protein content lower in the former than in the latter. The results suggest that natural photoperiod regulates the thyroid activity in vivo. In vitro studies revealed that the presence of T4 (3.12 microM) in the incubating medium stimulated the enzyme activity of brain homogenates possibly due to direct action on mitochondria. Immersion of fishes in thiourea solution (1 mg/ml) for 3, 5, and 7 days resulted in enhancement of enzyme activity after 7 days of treatment and of protein content after 5 days of treatment. Thyroid hormones in vivo appear to have an inhibitory effect on the carbohydrate metabolism of the nervous tissue.

Acclimatization↗
PubMed1983

Effect of short-term starvation stress on the age-related changes in hepatic SDH activity of the indian murrel, Channa punctatus.

Judging from correlation analysis it is evident that the fed control male and female murrels of the oldest classes have significantly higher SDH (EC 1.3.99.1) activity than the youngest classes of respective sexes. This is true for starved groups also. Starvation for 3 days led to an increase in hepatic enzyme activity over fed controls in three oldest groups (3+-, 4+- and 5+-yr classes) of female. This trend of raised activity was maintained in the same groups even in 7 days of starvation. On the other hand, in the male fish, 3 days of starvation caused an increase in hepatic enzyme activity over that in fed control fishes of all year classes barring those of 0+-yr class. Seven days of starvation failed to produce a significant change in enzyme activity in almost all age classes except in the 5+-yr class where the activity still remained at a higher level over that of fed controls.

Age Factors↗
PubMed1983

Carbohydrate metabolism of the brain in the ageing male garden lizard: effect of cold shock on mitochondrial respiration and lactate/pyruvate ratio.

Mitochondrial respiration with succinate as substrate increased and the mitochondrial protein content declined in the brain of the ageing male garden lizard. The lactate/pyruvate ratio of both blood and brain did not show appreciable changes with advancing age. Cold-shock treatment induced a significant rise in the respiratory rate of brain mitochondria of young but not appreciably in that of middle-aged and old lizards. On the other hand both mitochondrial protein content and lactate/pyruvate ratio increased only in the brain of cold-shocked lizards of the old age-group. The lactate/pyruvate ratio in blood remained unaltered following cold-shock treatment of lizards of all three age-groups.

Aging↗