Latest Research News on blood proteins : Aug – 2020

Glycated blood proteins in canine diabetes mellitus

Measurements of serum fructosamine and glycated haemoglobin are increasingly used to complement plasma glucose concentration in the fasting dog to diagnose diabetes mellitus and to monitor the response to treatment. These measurements are not affected by acute changes in the glucose concentration and reflect the average plasma glucose concentration over the preceding one to two weeks in the case of serum fructosamine and two to three months in the case of glycated haemoglobin. Both components can be measured in canine blood samples, but glycated haemoglobin is still not measured routinely; however, the serum fructosamine concentration can be measured accurately by means of simple spectrophotometric assays. The sensitivity and specificity of serum fructosamine in diagnosing diabetes mellitus in dogs with clinical signs of the disease are very high (0.93 and 0.95, respectively). Furthermore, serum fructosamine can be used as a reliable screening test to identify diabetic dogs in an average middle-aged to older hospital population. In addition, serum fructosamine can distinguish between hyperglycaemic non-diabetic dogs and hyperglycaemic diabetic dogs. Preliminary data suggest that therapy can be safely monitored and regulated on the basis of serial measurements of the serum fructosamine concentration in diabetic dogs. [1]

The conformation of adsorbed blood proteins by infrared bound fraction measurements

The likelihood that surface-induced blood coagulation results from specific protein-material interactions has led to a study of the conformation of adsorbed blood proteins. Infrared difference spectroscopy was used to determine the bound fraction, i.e., the fraction of carbonyl groups of an adsorbed molecule directly interacting with the surface, of serum albumin, prothrombin, and fibrinogen in situ. Measurements were carried out on individual proteins as a function of the amount adsorbed, time of absorption, pD, and ionic strength using a silica surface.

The results obtained for serum albumin and prothrombin indicate that the internal bonding of these globular proteins is sufficient to prevent changes in the structure while adsorbed, even at low surface population. The bound fraction of fibrinogen increases with increasing adsorbance, suggesting possible interfacial aggregation. The conformation of all three proteins was found to be independent of the time of adsorption, although major differences in the rates of adsorption were observed.

Studies of cross-linked and denatured serum albumin have provided information on the conformational changes concomitant with adsorption of the native protein. Qualitatively, such changes, if they occur, are small. This conclusion is supported by computer simulation studies of lysozyme adsorption. Studies of the effect of pD and ionic strength on the adsorbance and bound fraction of serum albumin show that caution must be exercised when identifying the plateau adsorbance of a protein isotherm with a close-packed monolayer. [2]

Peripheral Blood Proteins Predict Mortality in Idiopathic Pulmonary Fibrosis

Rationale: Idiopathic pulmonary fibrosis (IPF) is a lethal lung disease of unknown etiology with a variable and unpredictable course.

Objectives: The aim of this study was to identify and validate plasma proteins that are predictive of outcome in IPF.

Methods: Plasma samples were available for 241 patients with IPF (140 derivation and 101 validation). In the derivation cohort, concentrations of 92 proteins were analyzed using a multiplex bead-based immunoassay and concentrations of matrix metalloproteinase (MMP)-7, MMP-1, and surfactant protein D were assessed by ELISA. In the validation cohort concentrations of intercellular adhesion molecule (ICAM)-1, IL-8, and vascular cell adhesion molecule (VCAM)-1 were assessed by bead-based multiplex assay, and S100A12 and MMP-7 by ELISA. Associations of biomarkers with mortality, transplant-free survival, and disease progression were tested in the derivation and validation cohorts using nonparametric methods of survival analysis and the Cox proportional hazards model, and an integrated risk prediction score was derived and tested.

Measurements and Main Results: High concentrations of MMP-7, ICAM-1, IL-8, VCAM-1, and S100A12 predicted poor overall survival, poor transplant-free survival, and poor progression-free survival in the derivation cohort. In the independent validation cohort high concentrations of all five were predictive of poor transplant-free survival; MMP-7, ICAM-1, and IL-8 of overall survival; and ICAM-1 of poor progression-free survival. The personal clinical and molecular mortality prediction index derived in the derivation cohort was highly predictive of mortality in the validation cohort.

Conclusions: Our results suggest that plasma proteins should be evaluated as a tool for prognosis determination in prioritization of patients for lung transplantation and stratification in drug studies. [3]

 

Use of Staphylococcal Protein-A and Streptococcal Protein-G for Detection of Red Blood Cells (RBC) Antibodies and Comparison with Other Techniques

Background: Detection of red blood cells antibodies is important for the diagnosis of autoimmune hemolytic anemia, hemolytic disease of newborn, pre-transfusion testing and other problems. The aim of this study was to use Staphylococcal protein A (SpA) and Streptococcal protein G (SpG) as reagents in immunological tests for detecting red blood cells (RBC) antibodies and to compare the method with other techniques.

Study Design & Methods: Sera from 60 patients, comprising forty-four anti-D positive sera from pregnant women and 16 from healthy controls were, used for the study. The anti-globulin gel test and the standard Coombs’ test were used to determine RBC antibodies in these sera and the result were compared with that of protein A and protein G tests.

Results: With various degree of agglutination all 4 techniques detected the presence of RBC antibodies (anti-D) in the sera from 44 pregnant women, and tested negative for the remaining 16 sera (from healthy controls). The sensitivity and the specificity of the 4 techniques was 100%.

Conclusions: This preliminary study demonstrates that both SpA and SpG tests can be used for the detection of RBC antibodies and therefore requires more study and testing before they can become useful standard tests in transfusion medicine. [4]

Effects of Phytase Supplementation of Low Protein Diets on Performance, Egg Quality Traits and Blood Biochemical Parameters of Laying Hens

Effects of phytase supplementation of low protein diets on performance, egg quality traits and blood biochemical parameters of laying hens were evaluated by using 216 Lohmann LSL-Lite hens. Birds were randomly divided in 36 cages (n=6). Based on a 3×2 factorial arrangement of treatments, 6 iso-caloric experimental diets consisting three levels of crude protein (CP, 150, 138, and 126 g/kg) and phytase (0 and 300 FTU/kg) were formulated and fed to hens with 6 replicates per diet. Collected data of feed intake (FI), egg production (EP), egg mass (EM) and calculated feed conversion ratio (FCR), egg quality traits and blood parameters during 7-wk trial period were analyzed based on completely randomized design. Decreasing dietary crude protein significantly decreased EP, EM and FI and increased FCR (P < .05). In the first egg sampling (wk 3) egg index, yolk index, yolk color, egg gravity, shell weight and shell thickness were not significantly affected by dietary treatment (P > .05). Decreasing dietary CP significantly increased Haugh unit compared to the control group. In the second egg sampling period (wk 7), Haugh unit significantly decreased in the hens fed low protein diets compared to the control group (P < .05). Phytase supplementation did not have any beneficial effect on productive performance of laying hens and egg quality traits (P > .05). There was no interaction between protein level and phytase on egg traits except for egg index (P < .05). There was no interaction between CP levels and phytase on blood parameters except for Heterophil count (P < .01). Interaction between protein levels and phytase on lymphocyte as well as heterophil to lymphocyte (H/L) ratio was significant (P < .05). In conclusion, feeding low CP diets significantly decreased blood levels of cholesterol, triglycerides and LDL in compared to the control group (P < .05). [5]

Reference

[1] Jensen, A.L., 1995. Glycated blood proteins in canine diabetes mellitus. The Veterinary Record, 137(16), pp.401-405.

[2] Morrissey, B.W. and Stromberg, R.R., 1974. The conformation of adsorbed blood proteins by infrared bound fraction measurements. Journal of Colloid and Interface Science, 46(1), pp.152-164.

[3] Richards, T.J., Kaminski, N., Baribaud, F., Flavin, S., Brodmerkel, C., Horowitz, D., Li, K., Choi, J., Vuga, L.J., Lindell, K.O. and Klesen, M., 2012. Peripheral blood proteins predict mortality in idiopathic pulmonary fibrosis. American journal of respiratory and critical care medicine, 185(1), pp.67-76.

[4] Justiz Vaillant, A., Akpaka, P., McFarlane-Anderson, N. and P. Smikle, M. (2013) “Use of Staphylococcal Protein-A and Streptococcal Protein-G for Detection of Red Blood Cells (RBC) Antibodies and Comparison with Other Techniques”, Journal of Advances in Medicine and Medical Research, 3(4), pp. 1671-1677. doi: 10.9734/BJMMR/2013/3616.

[5] Kashani, S., Mohebbifar, A., Habibian, M. and Torki, M. (2013) “Effects of Phytase Supplementation of Low Protein Diets on Performance, Egg Quality Traits and Blood Biochemical Parameters of Laying Hens”, Annual Research & Review in Biology, 4(4), pp. 684-698. doi: 10.9734/ARRB/2014/4444.

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