Sachi Sri Kantha

Reversed phase HPLC analysis of α- and β-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 α- and β-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 α- and β-carotene in the cooked products was determined. Boiling for 30 minutes resulted in a 53 and 40% loss of β-carotene from lettuce and carrots, respectively. Full retention or even an increase in β-carotene content in boiled winged bean leaves and spinach was noted. Steaming resulted in very good retention of α- and β- 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 α- and β-carotene in others. The presence of carotenoproteins in some vegetables may effect the heat stability of extractability of α- and β- carotene.

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.

Intravenous administration of inorganic selenium compounds, inhibitors of prostaglandin D synthase, inhibits sleep in freely moving rats

Prostaglandin (PG) D2 has been postulated to be an endogenous sleep-promoting factor. Biosynthesis of PGD2 is catalyzed by PGD synthase (prostaglandin-H2 D-isomerase, EC 5.3.99.2), the activity of which is inhibited by inorganic selenium compounds such as SeCl4 and Na2SeO3. We recently examined the effect of intracerebroventricular administration of these selenium compounds on sleep in rats, and demonstrated time- and dose-dependent sleep inhibition. To establish whether this effect of selenium is also produced when the compound is administered systemically, we devised a procedure for intravenous catheterization and examined the effect of these selenocompounds on sleep-wake activity in freely moving rats (n = 35). Each test compound was administered into the inferior vena cava continuously between 11.00 and 17.00 h on the experimental day. SeCl4 time- and dose-dependently inhibited sleep at infusion rates of 5, 7.5, 10 and 20 nmol/microliters per min. During the SeCl4 infusion at 20 nmol/microliters per min, slow-wave sleep and paradoxical sleep were reduced to 63% and 50% of their respective baseline values. Na2SeO3 exhibited a similar sleep inhibition, though Na2SO3 was ineffective. Infusion of SeCl4 at 10 nmol/microliters per min or below produced no consistent changes in the mean brain temperature, or food and water intake during the infusion period. During the nocturnal period subsequent to SeCl4 infusion, sleep was increased by a rebound phenomenon, while a decrease in brain temperature and inhibition of food and water intake dose-dependently occurred. We conclude that systemic administration of these PGD synthase inhibitors has a sleep-reducing potency.

The winged bean as an oil and protein source: A review

Despite high protein contents in its ripe seeds, tubers and fresh leaves (ranging from 29.3–39.0%, 3.0–15.0% and 5.0–7.6% respectively) and the high quality of that protein, the winged bean (Psophocarpus tetragonolobus) remained an obscure food source until about 10 years ago. Recently, this legume has received increasing attention from scientists because of its potential multiple uses as a food protein source in the humid tropics. This article reviews the utilization and nutrition literature of winged bean published during the last 10 years. The following aspects are covered: classification of winged bean proteins, nutritional properties and antinutritional components of the protein, protein quality, functional properties, and protein-based food products. The oil content of winged bean seeds ranges from 15.0–20.4%, and use of the winged bean as a potential oilseed crop is discussed. Areas of needed research are identified and described.

Phosphorylation and immunological cross-reactivity of paramyosin: A comparative study

Abstract 1. 1. Paramyosins isolated from nematode Caenorhabditis elegans , clam Meretrix meretrix and Mercenaria mercenaria , scallop Patinopecten yessoensis , abalone Notohaliotis discus , lobster Homarus vulgaris and sea cucumber Holothuria leueospilata were examined for phosphorylation rate and immunological logical reactivity against anti- Meretrix α-paramyosin antiserum. 2. 2. A high phosphorylation was only observed with the α-forms of bivalve paramyosins from Meretrix, Mercenaria and Patinopecten . 3. 3. The enzyme-linked immunosorbent assay data also revealed that phosphorylatable paramyosins of catch muscle differed in structure from those of non-catch muscle.

Seasonal variation in levels of prostaglandins D2, E2 and F2α in the brain of a mammalian hibernator, the Asian chipmunk

Seasonal changes in the in vivo levels of the prostaglandins (PGs) PGD2, PGE2, and PGF2(alpha) were measured in the brain of the male Asian chipmunk, Tamias asiaticus (n = 111), which underwent hibernation during the period between November and March. The mean level of PGD2 ranged from 36.0 to 85.2 pg/g tissue from June to October and remained essentially unchanged (80.5 pg/g tissue) in December. However, the mean PGD2 level rose significantly to 128.6 pg/g tissue in February, and returned to 75.2 pg/g tissue in the following April, suggesting a correlation between PGD2 and hibernation phenomenon. While PGE2 level did not vary significantly throughout the year, PGF2(alpha), which appeared to be the most abundant among the three prostanoids, showed a marked circannual rhythm with a trough of 51.6 pg/g tissue in July, rising to 391.6 pg/g tissue in February and reaching the peak value of 492.7 pg/g tissue in April, the reproduction period.

Could nitroglycerine poisoning be the cause of Alfred Nobel's anginal pains and premature death?

The life of 19th century Swedish chemist cum inventor Alfred Nobel can be conveniently divided into two equal phases: pre-nitroglycerine phase (1833-1863) and nitroglycerine phase (1864-1896). According to the records of Ragnar Sohlman, his assistant during his last year of life, Nobels physical condition began to decline towards the end of the 1870s, and for the last 16 years he suffered from deep depression and anginal pains. Based on Nobels descriptions of his condition, on his prolonged experimentation with explosives, his strenuous work habit and some recent knowledge about nitroglycerine poisoning, I hypothesize that nitroglycerine poisoning was an aggravating factor which contributed to Nobels deteriorating health and premature death at the age of 63.

A sensitive method to screen for hydroxyl radical scavenging activity in natural food extracts using competitive inhibition ELISA for 8-hydroxy deoxyguanosine

Representative endogenous antioxidants and natural food extracts were screened for hydroxyl radical scavenging activity by an ELISA. Whereas conventional assays for hydroxyl radical scavenging activity use either spin traps following the induction of Fenton reaction or measure thiobarbituric acid-reactive substances, this assay measures 8-hydroxy deoxyguanosine liberated from the hydroxylation of deoxyguanosine by Cu2+/ascorbate system.

Scientific productivity of Einstein, Freud and Landsteiner

The scientific productivity of Albert Einstein was compared to that of designated controls Karl Landsteiner (an experimental scientist) and Sigmund Freud (an eminent theorist). Three assumptions made for this comparison were (1) that Einstein and his designated controls had equal scientific stature; (2) that their publications were produced in a similar, if not identical, sociocultural milieu; and (3) the number of publications is directly proportional to scientific productivity. At the end of their illustrious careers, Einstein, Freud and Landsteiner accumulated 315, 320 and 345 scientific publications respectively. Einstein was the sole author in 88% of his publications, which validates the third assumption. Thus, one can conclude that quantitative comparison of Einsteins total scientific publications with that of appropriate controls such as Landsteiner and Freud shows that Einsteins chronic ill health did not influence his scientific productivity.

Einstein's medical friends and their influence on his life

Albert Einstein had at least six medical friends who influenced his thoughts. In each period (Munich, Switzerland, Berlin and Princeton) of his life, one could identify the medically qualified individuals with whom Einstein was in close contact. These include Max Talmey, Heinrich Zangger, George Nicolai, Hans Mühsam, Janos Plesch and Gustav Bucky. They probably enriched Einsteins life and thoughts significantly by being mentors, confidants, intellectual sparring partners and research collaborators to him. With Mühsam, Einstein published a paper in a German medical journal. In collaboration with Bucky, he also received a US patent for a light-intensity self-adjusting camera in 1936.