Studies of the Metabolism of Asialotransferrins: Potentiation of the Catabolism of Human Asialotransferrin in the Rabbit

1974 ◽  
Vol 52 (3) ◽  
pp. 155-161 ◽  
Author(s):  
E. Regoeczi ◽  
M. W. C. Hatton ◽  
K.-L. Wong
Keyword(s):  
Tracer Technique ◽  
Transfer Rates ◽  
Dual Isotope ◽  
Human Transferrin ◽  
Isotope Tracer ◽  
Human Control ◽  
Homologous Protein ◽  
Catabolic Rate ◽  
The Difference ◽  
Control Protein

The catabolism and distribution of simultaneously injected rabbit transferrin and rabbit asialotransferrin was studied in five rabbits using a dual-isotope tracer technique. Similar studies were performed with human transferrin and human asialotransferrin in two humans, seven rabbits, and a rat.In all experiments, the catabolic rate of the asialotransferrin was higher than the corresponding value for the control protein. The difference averaged at 15% for rabbits and 29% for humans when homologous protein preparations were used. There were no concomitant differences in capillary transfer rates or in the partition of the labeled proteins between intra- and extravascular spaces.The catabolic rate of human transferrin in rabbits was not significantly different from that of the corresponding homologous protein. In contrast, human transferrin from which 92–100% of the sialyl residues had been removed was catabolized in rabbits at approximately 3.5 times the rate for homologous asialotransferrin. Substantial difference was found between the elimination of human control and asialotransferrins in the rat as well.

Studies of the Metabolism of Asialotransferrins: the in Vivo Behavior of Baboon and Rhesus Asialotransferrins

1975 ◽  
Vol 53 (12) ◽  
pp. 1255-1261 ◽  
Author(s):  
E. Regoeczi ◽  
M. W. C. Hatton ◽  
K.-L. Wong
Keyword(s):  
Hepatic Uptake ◽  
Average Increase ◽  
Tracer Technique ◽  
Short Term ◽  
Dual Isotope ◽  
Isotope Tracer ◽  
Catabolic Rate ◽  
Nonprimate Mammal ◽  
Reduced Data

The catabolism and distribution of rhesus and baboon asialotransferrins relative to the corresponding parent proteins were studied in rabbits using a dual isotope tracer technique. Also a similar study with the baboon proteins in a baboon is reported.The metabolic data obtained in rabbits with both rhesus and baboon transferrins was close to the values established in a previous study for rabbit transferrin. Desialylation resulted in an average increase in the fractional catabolic rate of rhesus transferrin by 22.7%. This change is similar to that found earlier with asialotransferrins from several nonprimate mammals which are thought not to interact with the hepatic asialoglycoprotein receptor.Two kinetically distinct fractions were identified in baboon asialotransferrin. One of these, amounting to approximately one-third of the protein, was eliminated from the circulation very rapidly. The remaining two-thirds constituted a slowly catabolized fraction which behaved in vivo similarly to rhesus asialotransferrin. Unlike the rapidly cleared fraction, elimination of the slowly catabolized fraction in baboon asialotransferrin is probably not mediated by the hepatic asialoglycoprotein receptor. An amount comparable to the rapidly eliminated fraction in baboon asialotransferrin was recovered with the liver of rats in short-term experiments. In rats which were preinjected with chicken acid α1-glycoprotein the hepatic uptake of baboon asialotransferrin was markedly reduced. Data obtained in the baboon agreed with the findings in rabbits, although transferrin turnover was slower in the baboon.From its behavior in vivo as an asialoglycoprotein, baboon transferrin shows greater resemblance to human transferrin than rhesus transferrin. This conclusion is supported by carbohydrate analyses which show an intermediate position for baboon transferrin between man and a nonprimate mammal (rabbit), and a similarity between rhesus and rabbit transferrins.

Studies of the Metabolism of Asialotransferrins: Relationship Between the Carbohydrate Composition of Bovine, Canine, and Porcine Asialotransferrins and their Metabolic Behavior in the Rabbit

1974 ◽  
Vol 52 (10) ◽  
pp. 845-853 ◽  
Author(s):  
M. W. C. Hatton ◽  
E. Regoeczi ◽  
K.-L. Wong
Keyword(s):  
Negative Charge ◽  
Transfer Rates ◽  
Dual Isotope ◽  
Isotope Tracer ◽  
Native Proteins ◽  
Terminal Galactose ◽  
The Difference ◽  
Metabolic Behavior ◽  
Galactosyl Residues

The catabolism and distribution of bovine, canine, and porcine asialotransferrins relative to the corresponding parent proteins were studied in rabbits using a dual-isotope tracer technique. The capillary transfer rates and the partitions between intra- and extravascular spaces of these asialotransferrins did not differ significantly from the corresponding values for the control proteins but the asialotransferrins were catabolized faster. However, the difference in catabolic rates only amounted to 13–20%, which was in the same order as established previously for rabbit asialotransferrin (15%) but was considerably less than for human asialotransferrin (350%). This behavior clearly indicates that, in contradistinction to human asialotransferrin, bovine, canine, and porcine asialotransferrins are not eliminated from the plasma of rabbits via the Ashwell–Morell pathway for asialoglycoproteins.To explain the discrepancy in the behavior in vivo of the heterologous asialotransferrins, the carbohydrate compositions of the native proteins were measured and compared. The data show that bovine, porcine, dog, and rabbit transferrins contain approximately half the amount of carbohydrate found for the human protein. Furthermore, the human asialotransferrin carbohydrate chains terminate with galactosyl residues, which can be cleaved by β-galactosidase, whereas bovine, porcine, dog, and rabbit asialotransferrins do not liberate galactose in the presence of β-galactosidase.These observations are consistent with the hypothesis that the rapid elimination of a heterologous asialotransferrin can only be expected if the terminal galactose residues are accessible and that the slightly accelerated catabolism of homologous and certain heterologous asialotransferrins is due to loss of negative charge from the protein.

scholarly journals True ileal digestibility of legumes determined by dual-isotope tracer method in Indian adults

2019 ◽  
Vol 110 (4) ◽  
pp. 873-882 ◽  
Author(s):  
Sindhu Kashyap ◽  
Aneesia Varkey ◽  
Nirupama Shivakumar ◽  
Sarita Devi ◽  
Rajashekar Reddy B H ◽  
...  
Keyword(s):  
Mung Bean ◽  
Deuterium Oxide ◽  
Protein Digestibility ◽  
Plant Protein ◽  
Tracer Technique ◽  
Feeding Method ◽  
Dual Isotope ◽  
Ileal Digestibility ◽  
Isotope Tracer ◽  
Plant Protein Sources

ABSTRACTBackgroundGood-quality plant protein sources are important for protein adequacy in a balanced diet. Legumes are known to be a source of good quality plant protein, but the true ileal digestibility of indispensable amino acids (IAAs) of commonly consumed legumes is not known in humans.ObjectivesIn this study we measured the true ileal IAA digestibility of 2H-intrinsically labeled chickpea, yellow pea, and mung bean (hulled and dehulled) protein, using the dual-isotope tracer technique referenced to a standard protein ([U-13C] spirulina). The study also aimed to validate the use of [U-13C] spirulina as a reference protein in this method.Methods2H-intrinsically labeled legumes, obtained by watering plants with deuterium oxide (2H2O), were administered in a plateau feeding method to healthy Indian adults to measure their true ileal IAA digestibility with the dual-isotope tracer technique, using [U-13C] spirulina protein or a 13C-algal IAA mixture as the standard.ResultThe true ileal IAA digestibilities (mean ± SD) of chickpea, yellow pea, and mung bean were 74.6 ± 0.8%, 71.6 ± 1.3%, and 63.2 ± 1.5%, respectively. The true mean ileal IAA digestibility of mung bean when referenced to [U-13C] spirulina protein or a 13C-algal IAA mixture did not differ significantly (63.2 ± 1.5% versus 64.0 ± 2.4%, P > 0.05). The true ileal IAA digestibility of mung bean improved to 70.9 ± 2.1% after dehulling.ConclusionsThe true mean ileal IAA digestibility of legumes in healthy Indian adults was lower than expected. Traditional processing techniques such as dehulling improve protein digestibility by about 8%. This study was registered in the Clinical Trials Registry of India (CTRI): CTRI/2017/11/010468 (http://ctri.nic.in, accessed on 28/03/2019).

scholarly journals Heat transfer to a moving wire immersed in a gas fluidized bed furnace

2021 ◽  
Author(s):  
Antonio Tannas
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Steel Wire ◽  
Transfer Rates ◽  
New Correlation ◽  
Bed Temperature ◽  
Molten Lead ◽  
The Difference ◽  
Considerable Work ◽  
Work Done

In order to replace hazardous molten lead baths in the heat treatment of carbon steel wire with environmentally friendly fluidized bed furnaces a better understanding is needed of their heat transfer rates. There has been considerable work done in examining heat transfer rates to large cylinders immersed in fluidized beds, and some on wire sized ones as well, but all previous studies have been conducted on static cylinders. In order to gain a deeper understanding of heat transfer rates to a moving wire immersed in a fluidized bed furnace an apparatus has been constructed to move a wire through a fluidized bed. The heat transfer rates were calculated using the difference in inlet and outlet temperatures, wire speed and the bed temperature. As predicted, correlations for static wire were found to under-predict heat transfer rates at higher wire speeds, so a new correlation was developed by modifying an existing one.

Variable transfer rates in superfluid helium films

1966 ◽  
Vol 290 (1420) ◽  
pp. 1-13 ◽  
Keyword(s):  
Thick Film ◽  
Superfluid Helium ◽  
Transfer Rate ◽  
Bath Surface ◽  
Helium Films ◽  
Third Sound ◽  
Transfer Rates ◽  
Superfluid Flow ◽  
Helium Bath ◽  
The Difference

From an experimental investigation of superfluid film transfer in narrow beakers in helium II it emerges that there are probably two kinds of film. A ‘normal’ film is formed by superfluid creep over a dry substrate. A ‘thick’ film remains when liquid has drained from a substrate that has previously been immersed in the liquid helium bath. A comparison has been made of the superfluid flow between the two types of film. Scatter of values of transfer rate associated with a normal film is attributed to third sound generated by bath waves impinging on the meniscus at the base of the film. The thick film shows an enhanced rate of transfer which can persist for long periods of time in quiet conditions, but which can be abruptly diminished by disturbances such as bath surface agitation. There is a maximum stable length for a thick film exhibiting the full enhanced rate. The enhanced rate can be as much as 60% greater than the normal rate at 1° K, but the difference between the two rates of transfer disappears above 1.8 °K. No enhanced rate of transfer at any temperature is observed in beakers as large as 8 mm diameter.

scholarly journals Physiologic requirement for iron in pregnant women, assessed using the stable isotope tracer technique

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Jie Cai ◽  
Tongxiang Ren ◽  
Jiaxi Lu ◽  
Jinghuan Wu ◽  
Deqian Mao ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Pregnant Women ◽  
Tracer Technique ◽  
Stable Isotope Tracer ◽  
Isotope Tracer

Performance analysis of screw compressors – numerical simulation and experimental verification

2011 ◽  
Vol 226 (4) ◽  
pp. 968-980 ◽  
Author(s):  
S H Hsieh ◽  
Y C Shih ◽  
W-H Hsieh ◽  
F Y Lin ◽  
M J Tsai
Keyword(s):  
Heat Transfer ◽  
Screw Compressor ◽  
Pressure Curve ◽  
Discharge Process ◽  
Transfer Rates ◽  
Outlet Port ◽  
Total Process ◽  
The Difference ◽  
Verification Process ◽  
Empirical Constants

This article describes a theoretical model and computer program for calculating the pressure–volume ( PV ) diagram and the efficiency of an oil-injected screw compressor. The proposed model considers the mass and energy conservation laws, the heat transfer between air and oil, the leakages through various paths, and the discharges of air and oil. The proposed program, which uses seven empirical constants to account for the difference between the flow and the heat-transfer rates in the screw compressor and those estimated by available correlations, solves for the efficiency and the pressure curve of the compressed air. A systematic methodology for the determination of the seven empirical constants is presented in this article. Optimization is carried out to determine the seven empirical constants. With the empirical constants, which are determined with four sets of experiments, the maximum difference between the calculated and measured results in the training process, the verification process and the total process is 2.0 per cent for the volumetric and isentropic efficiencies and 5 per cent for the pressure curve. In the discharge process, the pressure in the compression chamber is noted to be affected by the area of the outlet port and the pressure in the neighbouring chambers.

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