Biomedical subjects

S Sri Kantha

Publications and source records attributed to S Sri Kantha.

8 recordsLinked to original sources

PubMed2001

Total immediate ancestral longevity (TIAL) score as a longevity indicator: an analysis on Einstein and three of his scientist peers.

The total immediate ancestral longevity (TIAL) score was first introduced by Raymond Pearl as a convenient parameter for quantitating human longevity. TIAL is the summed ages at death of the six immediate ancestors (namely parents and four grandparents) of a propositus. In this communication, I present the calculations of TIAL score for Einstein (1879--1955) and three of his scientist peers, namely Charles Darwin (1809--1882), Irene Joliot Curie (1897--1956) and Aage Bohr (1922--). The TIAL scores for Einstein, Darwin, Irene Curie and Aage Bohr were 390, 378, 372 and 436 respectively. These are markedly lower than 477 reported for Jeanne Calment, the French woman who died in 1997 at the oldest authenticated age of 122 years and 164 days. I conclude that the TIAL score is a convenient and easily quantifiable longevity parameter which anyone interested in determining his or her longevity can use to estimate a tentative number. More light could be shed on the worth of the TIAL score as a longevity indicator, if additional data on the TIAL scores of royalty and celebrities (for whom verified genealogical data are available) are reported.

Biology↗

PubMed2001

Centenarian scientists: an unusual cluster newly formed in the 20th century.

From biographical data sources on ranking scientists, I was able to identify 35 centenarians. Among these, only one (Michel Chevereul from France) lived before the 20th century. Since the remaining 34 individuals became centenarians only from 1965, I propose that centenarian scientists are an unusual cluster, first formed in the 20th century. Among these, all except one (Alice Hamilton) were men. Six centenarian scientists, including Hamilton, had received professional medical training. The nationality ranks of the 34 centenarian scientists identified in the 20th century show 26 Americans, 6 British, one German and one French. Four of the 26 Americans were immigrants from Europe. At least three centenarians, namely Michael Heidelberger, Nathaniel Kleitman and Victor Hamburger, belong to the 'Nobel class' category, being pioneers in the disciplines of immunochemistry, sleep physiology and neuroembryology respectively.

Aged↗

PubMed1997

Prostaglandin D synthase (beta-trace protein): a molecular clock to trace the origin of REM sleep?

In 1965, Zuckerkandl and Pauling proposed a novel concept that some important molecules termed semantides, which carry the information of the genes or a transcript thereof, can be used as molecular clocks to trace evolutionary history. According to this concept, enzymes are designated as tertiary semantides, following genes (primary semantides) and the mRNA (secondary semantides). Based on this idea, I propose that prostaglandin D synthase (which has been demonstrated recently as identical to the beta-trace protein present in the cerebrospinal fluid of mammals) may serve as a molecular clock to trace the origin and evolution of rapid eye movement sleep in the vertebrates.

Animals↗

PubMed1994

Effects of prostaglandin D2, lipoxins and leukotrienes on sleep and brain temperature of rats.

Prostaglandin (PG) D2 and four lipoxygenase-derived eicosanoids [lipoxins (LX) A4 and B4, and leukotrienes (LT) C4 and D4] were examined for their effects on sleep and brain temperature in freely-behaving rats. In the first series of experiments, PGD2 was infused into the third ventricle at four different locations between 23:00 and 05:00. In a location apposed to the medial preoptic area (MPO), PGD2 at doses 1, 10 and 100 pmol/min, increased the slow wave sleep (SWS) by 23% (p < or = 0.01), 35% (p < or = 0.05) and 44% (p < or = 0.01), respectively, during the infusion period. In the second series of experiments, LXs and LTs were infused at the location apposed to MPO. Significant increases in SWS were detected with LXA4 at 100 pmol/min (14%, p < or = 0.05), LXB4 at 100 pmol/min (20%, p < or = 0.05), and LTD at 10 pmol/min (17%, p < or = 0.05). An increase in paradoxical sleep (PS) was produced by PGD2 at 1 and 10 pmol/min infusion (p < or = 0.05), but not by any of the lipoxygenase-derived eicosanoids examined. PGD2 also elevated the mean brain temperature during infusion by 0.2 degrees C and 0.9 degrees C at infusion doses 10 and 100 pmol/min, respectively. But PGD2 infusion at 1 pmol/min did not elevate the brain temperature. LXs (excluding LXB4 at 100 pmol/min) and LTs did not alter the brain temperature significantly at the tested doses. We conclude that PGD2 is the most effective sleep promoter among the eicosanoids examined so far.

Animals↗

PubMed1994

Challenges for space medicine.

Since April 1961, when Yuri Gagarin first orbited the earth about 270 astronauts (predominantly males) have lived in space. More than 90 percent of these astronauts were natives of the USA and the ex-USSR. In this commentary, the challenges confronting the discipline of space medicine are reviewed. These include, (1) space sickness, (2) wasting of the musculoskeletal system and (3) developing a longterm life support system.

Aerospace Medicine↗

PubMed1991

The question of nepotism in the award of Nobel prizes: a critique of the view of Hans Krebs.

While reviewing his development as a scientist, in 1967, Hans Krebs traced his scientific geneology to the von Baeyer 'family'. Almost every other member of this scientific family became a Nobel laureate. Krebs was of the opinion that there was no nepotism in the selection of the Nobel awards. This paper presents evidence, based on the recently released census of Nobel nominees and nominators for the chemistry prize between 1901 and 1937, that the von Baeyer 'family' of scientists had in fact practised a sort of 'nomination-nepotism'.

Chemistry↗

PubMed1988

Reversed phase HPLC analysis of alpha- and beta-carotene from selected raw and cooked vegetables.

Traditional AOAC colorimetric procedures for carotenoid analysis are known to lack specificity and accuracy. Newer HPLC methods provide the investigator with a more precise tool for carotenoid quantification in foods and tissues. In the present studies, reverse phase HPLC was utilized to evaluate the alpha- and beta-carotene content in raw and cooked leaves of lettuce, spinach and winged bean as well as in the carrot root. The vegetables were boiled or steamed and the true retention of alpha- and beta-carotene in the cooked products was determined. Boiling for 30 minutes resulted in a 53 and 40% loss of beta-carotene from lettuce and carrots, respectively. Full retention or even an increase in beta-carotene content in boiled winged bean leaves and spinach was noted. Steaming resulted in very good retention of alpha- and beta-carotene in all vegetables (83-139% retention). Thus, although cooking procedures (especially boiling) may result in oxidative loss of carotenoids in some vegetables, heat treatment increases the chemical extractability of alpha- and beta-carotene in others. The presence of carotenoproteins in some vegetables may affect the heat stability of extractability of alpha- and beta-carotene.

Carotenoids↗

PubMed1987

Legume carotenoids.

In recent years, the results of research studies have suggested a positive beneficial relationship between a vegetarian-based diet and low incidence of diseases, including coronary heart disease, cancer, obesity, dental caries, and osteoporosis. beta-Carotene has specifically been suggested as a nutrient with antitumorigenic properties. In this regard there is a need to evaluate the carotenoid content of foods. Legumes are one of the staple components of a vegetarian diet. This review specifically surveys the prevalence of carotenoids in food and forage legumes. In addition, the methods available for carotenoid analysis are discussed; factors affecting the determination of carotenoid content during maturation, germination, processing and storage are identified; research areas which have been inadequately explored are identified; and suggestions are made for future lines of investigation.

Carotenoids↗