Application of Micro -Computer in a Performance Measurement System of Reciprocating Compressors

textabstractINTRODUCTION: Lysine is the first limiting essential amino acid in the diet of newborns. First pass metabolism by the intestine of dietary lysine has a direct effect on systemic availability. We investigated whether first pass lysine metabolism in the intestine is high in preterm infants, particularly at a low enteral intake. PATIENTS AND METHODS: Six preterm infants (birth weight 0.9 (0.1) kg) were studied during two different periods: period A (n = 6): 40% of intake administered enterally, 60% parenterally; lysine intake 92 (6) micromol/(kg x h); and period B (n = 4): 100% enteral feeding; lysine intake 100 (3) micromol/(kg x h). Dual stable isotope tracer techniques were used to assess splanchnic and whole body lysine kinetics. RESULTS: Fractional first pass lysine uptake by the intestine was significantly higher during partial enteral feeding (period A 32 (10)% v period B 18 (7)%; p<0.05). Absolute uptake was not significantly different. Whole body lysine oxidation was significantly decreased during full enteral feeding (period A 44 (9) v period B 17 (3) micromol/(kg x h); p<0.05) so that whole body lysine balance was significantly higher during full enteral feeding (period A 52 (25) v period B 83 (3) micromol/(kg x h); p<0.05). CONCLUSIONS: Fractional first pass lysine uptake was much higher during partial enteral feeding. Preterm infants receiving full enteral feeding have lower whole body lysine oxidation, resulting in a higher net lysine balance, compared with preterm infants receiving partial enteral feeding. Hence parenterally administered lysine is not as effective as dietary lysine in promoting protein deposition in preterm infants

A comparison of body protein determination in rats by in vivo neutron activation and carcass analysis

Total body nitrogen (TBN) was determined in 16 rat carcasses ranging in weight from 55 to 550 g, by non-destructive 14 MeV neutron activation analysis (NAA). The rat carcasses were subsequently analysed for TBN by Kjeldahl digestion, for total body water (TBW) by loss of weight after freeze-drying and for body fat by adiabatic bomb calorimetry after subtraction of protein energy. TBN results by the two methods were in good agreement, the precision by NAA (coefficient of variation = 1.5%) being superior to that by chemical analysis (coefficient of variation = 2.8%). Body fat calculated by difference from a combination of measured TBW and NAA data agreed closely with bomb calorimetry measurements. The use of indirect estimates of TBW to determine fat gave poor results. A group of four growing rats was analysed sequentially by NAA four times in 2 weeks. The maximum total radiation dose received by each animal was less than 50 rem (less than 500 mSv) and no significant differences in growth rate were observed compared with non-irradiated control groups. 14 MeV NAA in vivo can be conducted with sufficient precision to measure 0.14 g TBN changes in growing rats at 2 weeks post-weaning

Effects of the amount and quality of dietary protein on nitrogen metabolism and protein turnover of pigs

1. The interrelation between protein accretion and whole-body protein turnover were studied by varying the quantity and quality of protein given to growing pigs.&lt;p&gt;&lt;/p&gt; 2. Diets with 150 or 290 g lysine-deficient protein/kg were given in hourly meals, with or without lysine supplementation, to female pigs (mean weight 47 kg).&lt;p&gt;&lt;/p&gt; 3. After the animals were adapted to the diets, a constant infusion of [14C]urea was given intra-arterially for 30 h, during the last 6 h of which an infusion of [4,5-3H]leucine was also infused at a constant rate. At the same time, yeast-protein labelled with 15N was given in the diet for 50 h.&lt;p&gt;&lt;/p&gt; 4. The rate of urea synthesis was estimated from the specific radioactivity (SR) of plasma urea. The rate of leucine flux was estimated from the SR of plasma leucine. The irrevocable breakdown of leucine was estimated from the 3H-labelling of body water. Total N flux was estimated from the 15N-labelling of urinary urea.&lt;p&gt;&lt;/p&gt; 5. Addition of lysine to the low-protein diet significantly increased N retention, with a substantial reduction in leucine breakdown, but there was no significant change in the flux of leucine or of total N.&lt;p&gt;&lt;/p&gt; 6. Increasing the quantity of the unsupplemented protein also increased N retention significantly, with concomitant increases in leucine breakdown and in the fluxes of leucine and of total N.&lt;p&gt;&lt;/p&gt; 7. It is concluded that a doubling of protein accretion brought about by the improvement of dietary protein quality is not necessarily associated with an increased rate of whole-body protein turnover