Iron-containing proteins and the proteolytic activity in the blood serum in hyperbaric oxygenation and the protective action of urea

The number and composition of ferro-containing proteins, the total number of iron, summary peroxidase activity and peptide-hydrolase activity have been determined under different hyperbaro-oxygenation (HBO) in blood serum. It has been established that under HBO the concentration of ferro-containing proteins increases, the fraction composition of serum and erythrocyte haemoglobin changes, the activity of acid peptide-hydrolases increases and the protamine-splitting peptide-hydrolase activity lowers. The administration of urea before HBO-experiments leads to the normalization of the most biochemical indicators of blood serum. The tests of oxygen intoxication depth assessment have been suggested.     

Iron content of the blood and saturation of serum transferrin with iron as affected by roentgen rays

Total-body X-irradiation of rabbits with a dose of 4.5 Gy caused appreciable changes in the iron content of blood and iron saturation of blood serum transferrin over a period from 30 min to 30 days. The pattern of changes in the indices under study depended upon the time lapsed after irradiation.     

Concentration of transferrin iron and transferrin saturation in blood

Transferrin iron, transferrin protein concentrations, and transferrin saturation have been determined for the first time in the whole blood. Microsamples were taken from healthy adults and patients with occupational secondary haemochromatosis using quantitative electron spin resonance technique. At elevated transferrin saturation, transferrin saturation values determined in the plasma and serum samples were shown to be less than respective values determined in the whole blood of the same patients. At increased transferrin iron concentration the difference between experimental and reference data sets determined in the blood and plasma was statistically significant in contrast to data sets determined in serum. Therefore, the analysis of the blood microsamples ensured an adequate estimation of transferrin iron concentration, especially at high transferrin saturation. A new index--transferrin iron concentration in the formed blood elements--was introduced. The values of the index were determined in the groups of healthy adults, patients with secondary occupational hemochromatosis and healthy newborns.     

The total protein content in the blood serum of vertebrates

The total protein content in the blood serum of 416 species and subspecies of vertebrates is determined by the microbiuret method. Generally speaking the total protein content of the serum shows an increase with a higher evolutionary level. The difference between the mammals and the other groups is particularly large. This increase is probably attributable to a number of factors, for instance adaptation to living on land, development of the circulatory system, the development of adaptive immunity and the forming of specific transport proteins. A connection between albumin content and level of development can also be noticed.     

Comparison of serum iron, total iron binding capacity, ferritin, and percent transferrin saturation in nine species of apparently healthy captive lemurs

Lemurs kept in captivity have been reported to be highly prone to accumulate excessive amounts of iron in tissues (hemosiderosis). Diagnosis of the condition is most commonly made during a postmortem examination because an antemortem diagnosis requires a liver biopsy, a procedure that may not be well tolerated by all animals. The lack of a noninvasive method to evaluate iron status in captive lemurs limits investigators' ability to effectively screen animals for the presence of hemosiderosis, and to detect the condition early when treatment protocols are most effective. This study was conducted in an effort to provide data regarding iron analyte values in healthy captive lemurs of multiple species. The relationship of various iron-related metabolites was evaluated in 177 clinically normal lemurs of nine different species. Serum iron (sI), total iron binding capacity (TIBC), and ferritin concentration were measured directly and the percent transferrin saturation (TS) was calculated. Significant differences in various iron metabolites were observed among several species, suggesting that normal reference values for iron metabolites in lemurs may need to be developed on a species by species basis.     

Nycthemeral variations of blood and urine urea, creatinine and total proteins in rats]

The present study evidences blood and urine urea, creatinine and total proteins circadian variations in 50 male rats. Venous blood is sampled at behind socket sinus once a week at different hours (8, 11, 14, 17, 20, 23, 2 and 5) and urines are collected during 4 consecutive six hours periods in animals living in metabolism cages (8-14, 14-20, 20-2, 2-8). Blood three nitrogen substances circadian variations bring out the decrease at 17 h and increase at 23 or 2 h. Urinary excretion variations curves shows, in all cases, an increase more than 40% during the nightly periods. The influence of feeding rhythms on the blood and urine three derivates circadian rhythms is discussed. Moreover, night diuresis increase and urea and creatinine urinary remarkable constancy suggest water, solutes and macrosolutes transglomerular pathway nightly increase existence. Urea (+ 40%) and creatinine (+ 30%) clearance nightly significative increase confirms glomerular filtration circadian variations and its nightly increase.     

Effect of alpha-lipoic acid preparations on bilirubin and transferrin levels and ferritin iron and transferrin iron content

The influence of ethylendiamine salt of alpha-lipoic acid on the indices of iron metabolism in patients with occupational pathologies has been studied using quantitative electron spin resonance spectroscopy. In the cases of treatment in the patients suffering from hyperferremia the decrease in transferrin iron concentration in the whole blood and plasma occurs correlating with the enhancement of iron excretion from urine and decline of bilirubin level in serum. We have found that the preparation chelates iron from iron (III)-citrate complex and form stable iron (III) complexes. The conclusion is that the positive effects of lipoic acid preparation in the patients with hyperferremia at least partially could be associated with normalization of iron exchange and reduction in the labile iron pool.     

Serum copper and zinc values compared with serum iron,total iron-binding capacity,and transferrin saturation in sickle cell trait

Reliable data for the trace element values of the biological systems in some diseases are still very rare. Sickle cell trait is one of them. For this purpose, serum iron, zinc, and copper values, together with the total iron binding capacity and saturation percent, were determined in cases with sickle cell trait, eliminating all the sources contributing to deviations from the normal values by choosing a control group from the relatives of the cases. In this study, the values of two groups were compared on the basis of the difference in hemoglobin type, which was the only parameter affecting the trace element analysis.     

Elucidating the mode of action of urea on mammalian serum albumins and protective effect of sodium dodecyl sulfate

The effect of sodium dodecyl sulfate (SDS) on human, bovine, porcine, rabbit and sheep serum albumins were investigated at pH 3.5 by using various spectroscopic techniques like circular dichroism (CD), intrinsic fluorescence and dynamic light scattering (DLS). In the presence of 4.0 mM SDS the secondary structure of all the albumins were not affected as measured by CD but fluorescence spectra revealed 8.0 nm blue shift in emission maxima. We further checked the stability of albumins in the absence and presence of 4.0 mM SDS by urea and temperature at pH 3.5. In the absence of SDS, urea starts unfolding both secondary as well as tertiary structural elements of the all the albumins at ∼2.0 M urea but in the presence of 4.0 mM SDS, urea was unable to unfold even up to 9.0 M. The albumins were thermally less stable at pH 3.5 with decrease in T_m but in the presence of 4.0 mM SDS, the T_m was increased. From this study, it was concluded that SDS is showing a protective effect against urea as well as thermal denaturation of albumins. This behavior may be due to electrostatic as well as the hydrophobic interaction of SDS with albumins. Further, we have proposed the mechanism of action of urea. It was found that urea interacted with proteins directly when proteins are in charged form. Indirect interaction may be taking place when the environment is more hydrophobic.     

Ionic residues of human serum transferrin affect binding to the transferrin receptor and iron release

Efficient delivery of iron is critically dependent on the binding of diferric human serum transferrin (hTF) to its specific receptor (TFR) on the surface of actively dividing cells. Internalization of the complex into an endosome precedes iron removal. The return of hTF to the blood to continue the iron delivery cycle relies on the maintenance of the interaction between apohTF and the TFR after exposure to endosomal pH (≤6.0). Identification of the specific residues accounting for the pH-sensitive nanomolar affinity with which hTF binds to TFR throughout the cycle is important to fully understand the iron delivery process. Alanine substitution of 11 charged hTF residues identified by available structures and modeling studies allowed evaluation of the role of each in (1) binding of hTF to the TFR and (2) TFR-mediated iron release. Six hTF mutants (R50A, R352A, D356A, E357A, E367A, and K511A) competed poorly with biotinylated diferric hTF for binding to TFR. In particular, we show that Asp356 in the C-lobe of hTF is essential to the formation of a stable hTF-TFR complex: mutation of Asp356 in the monoferric C-lobe hTF background prevented the formation of the stoichiometric 2:2 (hTF:TFR monomer) complex. Moreover, mutation of three residues (Asp356, Glu367, and Lys511), whether in the diferric or monoferric C-lobe hTF, significantly affected iron release when in complex with the TFR. Thus, mutagenesis of charged hTF residues has allowed identification of a number of residues that are critical to formation of and release of iron from the hTF-TFR complex.     

Immunoglobulin and antibody content in the blood serum, coprofiltrate and saliva of patients with Sonne dysentery]

The authors studied the immunoglobulin and specific antibodies content of various classes in the serum, coprofiltrates and the saliva of 68 patients suffering from Sonne dysentery and in 48 healthy adult persons. Mancini's test demonstrated a significant elevation of IgG and IgM content in the blood of dysentery patients in comparison with that in healthy persons, and the absence of any changes in the IgA content. The titres of specific IgG-, IgA- and IgM-antibodies in determination in the modified Coombs' test increased consideerably during dysentery infection and were found in high titres during the first week of the disease; they reached the maximum during the second week and persisted at this level for 3 weeks. The greatest antibody elevation was in the IgA-class. Antibodies revealed in the coprofiltrates and the saliva of dysentery patients belonged to IgA- and IgG-class. There proved to be a correlation of the antibody changes in these two secretions.     

EPR study of serum ceruloplasmin and iron transferrin in myocardial infarction.

Electron paramagnetic resonance (EPR) analysis of frozen serum from myocardial infarction patients has been conducted. Signal at g=4.3 was found definitively attributable to iron(III)-transferrin complex. Imcrease of serum ceruloplasmin as compared to normal was confirmed, with a concomitant decrease of iron-transferrin content. A mechanism for such correlated variation is hypothesized.