Methods have been developed for the labelling of acetate and palmitic acid with the positron-emitting radionuclide,11C (T=20.4 min). Labelling was achieved via carbonation of the appropriate alkyl magnesium bromide (methyl magnesium bromide
or n-pentadecyl magnesium bromide) with11C-labelled carbon dioxide produced by the14N(p, α)11C nuclear reaction. The radiochemical yield and speed of each method of labelling are such that a radiochemically pure product
is obtained in injectable form and in activity (>10 mCi) suitable for the study of myocardial metabolism by emission-computerised
axial tomography. High pressure liquid chromatography and thin layer chromatography were used to assess the radiochemical
purity of each radiopharmaceutical. The specific activity of11C-labelled acetate was estimated by an enzymic procedure to be greater than 0.5 Ci/μmole.
Brain tissue samples, obtained from the Alzheimer Disease Brain Bank,Institute of Psychiatry, London, were taken from both left and right hemispheresof three regions of the cerebrum, namely the frontal, parietal and occipitallobes for both Alzheimer and 'normal' subjects. Trace elementconcentrations in the frontal lobe were determined for twenty six Alzheimer(15 male, 11 female) and twenty six 'normal' (8 male, 18 female)brain tissue samples. In the parietal lobe ten Alzheimer (2 male, 8 female)and ten 'normal' (8 male, 2 female) samples were taken along withten Alzheimer (4 male, 6 female) and ten 'normal' (6 male, 4 female)from the occipital lobe. For the frontal lobe trace element concentrationswere determined using proton induced X-ray emission (PIXE) analysis whilein parietal and occipital regions instrumental neutron activation analysis(INAA) was used. Additionally eighteen Alzheimer (9 male, 9 female) and eighteenage matched 'normal' (8 male, 10 female) living subjects wereexamined using positron emission tomography (PET) in order to determine regionalcerebral metabolic rates of glucose (rCMRGlu). The rCMRGlu of 36 regions ofthe brain was investigated including frontal, occipital and parietal lobesas in the trace element study. Hierarchical cluster analysis was applied tothe trace element and glucose metabolism data to discover which variablesin the resulting dendrograms displayed the most significant separation betweenAlzheimer and 'normal' subjects.
After the occurrence of 'Minamata disease' in 1950,
mercury aroused much more attention, and lots of studies concerned have been
made. The purpose of the present paper is to study the effect of mercuric
chloride on the mitochondria suspension isolated from the liver tissue of Cyprinus carpio from the direct viewpoint of energy
by using the microcalorimetric method. The metabolic thermogenic curves of
the mitochondria suspension at 25C were obtained, and the mitochondria
metabolic thermokinetic equations were established, from which we obtained
the thermodynamic and thermokinetic parameters: thermogenic rate constant
(k), heat output (Q),
average heat power (Pav),
etc. Experimental results indicated that low concentration of mercuric chloride
(5 nmol Hg2+/(mg protein)) stimulates the thermogenesis
of mitochondria, suggesting a strong effect of uncoupling action, while high
concentration of mercuric chloride (20 nmol Hg2+/(mg
protein)) inhibits the metabolism of mitochondria completely, suggesting a
fatal effect on the phosphorylation system. The effect of Hg2+
on mitochondria is concentration-depended, from which the probable reaction
mechanism of Hg2+ to the mitochondria was proposed.
So the microcalorimetric method can be used in the toxicology research.
Two wheat genotypes were grown in hydroponic culture, containing 4 mM KNO3, NH4Cl and NH4NO3. Activities of N metabolizing enzymes, aminotransferases, carbohydrate and TCA cycle enzymes were analyzed along with protein, amino acid, N, sugar content and growth parameters in shoot and root. After 12 days, the size of shoot and root system decreased significantly when plants were supplied with NH4Cl as exclusive N source. Under NH4NO3 growth parameters, N and carbon metabolism were elevated as compared to NH4Cl but less than KNO3 source indicating inhibition of NH4+ toxicity by NO3− uptake. Our results suggested that GDH, aminotransferases and PEPC play an important role in ammonium detoxification by its incorporation into amino acids. Thus, the morphologic differences among plants growing in NH4+ or NO3− nutrition confirm the hypothesis that N source determines the growth habit of plant in wheat by modulating the endogenous levels of protein and sugar content.
Present investigation reports the variability in phenolics and activities of some enzymes involved in their metabolism in pericarp tissue of ‘Calcuttia’ and ‘Seedless’ cultivars harvested at one week interval after fruit set. Total phenolics, flavonols, and phenolic acid contents in litchi fruit pericarp increased after 49 days following fruit set (DAFS), while proanthocyanins showed a small increment initially and then decreased significantly up to maturity. Polyphenol oxidase, phenylalanine ammonia lyase, and cinnamate-4-hydroxylase activities followed the similar trend as observed in phenolic content at respective developmental stages, while peroxidase activity in pericarp was low at initial stages and increased gradually with fruit development. Higher phenolic content with low polyphenol oxidase activity in pericarp during initial stages of fruit development in ‘Seedless’ as compared to ‘Calcuttia’ cultivar suggests the slow ripening. A negative correlation between anthocyanin content and anthocyanase activity was recorded. Total phenolic constituents, ferric reducing antioxidant power (FRAP), and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging activity showed positive correlation with higher values of these parameters in ‘Seedless’ as compared to ‘Calcuttia’ cultivar. Knowing the phenolic profiles, antioxidant activity, and activity of related enzymes during fruit development gives the insights into its potential application to reduce the post-harvest browning of litchi.
Non-starch polysaccharides (NSPs) form an integral part of the cell walls in plants and represent considerable available energy when degraded into absorbable mono-, di-, tri- and oligosaccharides. The ruminal microflora hydrolyses a good part of NSPs, however, recently there have been attempts to enhance the rate of utilisation by using external polysaccharidase enzymes. In the present study the effects of an enzyme preparation (Rumino-Zyme) high in xylanase activity were studied on ruminal volatile fatty acid (VFA) concentration, parameters of energy and protein metabolism, milk yield, feed conversion ratio (FCR) and body condition score of high-yielding dairy cows. A lignolytic enzyme preparation produced by the thermophilic fungus Thermomyces lanuginosus was applied in the present experiment and fed to dairy cows at 34 g/day dosage in the period between calving and the 110th day of lactation. This preparation increased VFA concentration in the rumen from about 32 days after calving and onward. Increased VFA concentration was followed by an about 5 to 10% increase in milk production and an almost 0.1% increase in butterfat production. Increased VFA concentration produced more balanced energy metabolism in the experimental cows as indicated by the lower incidence rate of hyperketonaemia, and lower acetoacetic acid and non-esterified fatty acid (NEFA) concentration in the blood of the experimental cows. Aspartate aminotransferase (AST) activity was tendentiously higher in the control group and the proportion of cows that had AST activity higher than 100U/l was also higher in the control group. Both control and experimental cows showed balanced protein and acid-base metabolism throughout the experiment. Enhanced VFA concentration contributed to an improvement in energy balance in the experimental cows with a resultant improvement of feed intake and feed utilisation. Due to the more balanced energy metabolism postparturient body condition loss of the treated cows was reduced.
In order to study the metabolism of physiological amounts of51Cr (10 μg/100 g of body wt.) intragastrically administered in rats, the activable enriched stable isotope Cr-50 compound Cr2O3 was used as a tracer. The absorption and distribution of51Cr(III) in rats with time were studied. Significant51Cr contents were found in all the organs and tissues of interest. The kidney, liver and bone contain higher amounts of51Cr than others. The fact that specific activities of51Cr are notably high in kidney, bone, spleen and pancreas and decrease gradually with time suggests that there are tighter
binding of chromium in these organs. The excretion of51Cr at various time intervals was also studied. Almost totally intragastrically administered dose was excreted in the feces.
The increased urinary excretion of51Cr with time indicates that the urine-chromium is the metabolic derivative of organism. In view of the tissues distribution
and excretion, it can be concluded that no more that 1% of the dose was absorbed from the gastrointestinal tract.
vitro observations Life Sci. 67 605 – 615 .
. G. Salen E. H. Ahrens S. M. Grundy 1970 Metabolism of beta-sitosterol in man J. Clin. Invest. 49 952 – 967 .
. B. J. Kudchodkar H. S. Sodhi L. Horlick 1973