Serum Proteins

Understanding how ultrasmall gold nanoparticles (metal core ∼1−1.5 nm), so-called gold nanoclusters (Au NCs), interact with biological barriers has become highly important for their future bioapplications. The properties of Au NCs with tunable hydrophobicity were extensively characterized in three different biological situations: (i) interaction with serum in solution, (ii) interaction with synthetic free-standing lipid bilayers integrated in a microfluidic device, and (iii) cell studies with two different cell types (U87MG human primary glioblastoma and A375 melanoma cell lines). Our results indicate a significant impact of the precise tailoring of the hydrophilicity/hydrophobicity balance on the Au NC surfaces, which could prevent the formation of biomolecular absorption while maintaining excellent colloidal stability in solutions with high serum contents. Increasing the surface hydrophobicity of the Au NCs enabled more efficient lipid bilayer membrane insertion and induced faster cellular uptake. We showed the existence of a hydrophobicity threshold, which resulted in colloidal instability, lipid bilayer damage, and acute cytotoxicity. We also demonstrated a significant influence of metal−ligand shell hydrophobicity on the fluorescence signal of the Au NCs, increasing it in the near-infrared region. A twofold signal enhancement was achieved by simple replacement of methyl groups with ethyl groups.

Background: Proteins that are associated with hypertension may be identified by comparing the 2-dimensional gel electrophoresis (2-DE) profiles of the sera of spontaneously hypertensive rats (SHR) with those generated from normotensive Spraque-Dawley rats (SDR). Results: Five proteins of high abundance were found to be significantly altered when the 2-DE serum profiles of the SHR were compared to those that were similarly generated from the SDR. Analysis by mass spectrometry and database search identified the proteins as retinol binding protein 4, complement C3, albumin (19.9 kDa fragment), alpha1 macroglobulin and alpha1 antiproteinase, which are all known to be associated with hypertension. The altered expression of the two latter proteins was found to be abrogated when similar analysis was performed on sera of the SHR that were treated with captopril. Conclusion: Our data suggests that serum alpha1 macroglobulin and alpha1 antiproteinase are potentially useful complementary biomolecular indicators for monitoring of hypertension.

Dengue is an arbovirus disease transmitted mainly by Aedes mosquitoes. As dengue shares
similar clinical symptoms with other infectious diseases, prompt and accurate diagnosis is pivotal
to clinicians’ decisions on appropriate management. Conventional diagnostic tests to detect the
dengue-specific IgM antibody are limited in their performance and ease of use. To address these
issues, we developed and evaluated a biosensor based on screen-printed carbon electrodes (SPCEs)
for the detection of dengue-specific immunoglobulinM(IgM) antibodies. Various optimisations were
performed in order to increase the sensitivity and specificity of the biosensor. For optimal and proper
orientation of the paratope sites of goat anti-human IgM capture antibodies (GAHICA), various antibody
techniques, including passive, covalent, protein A, protein G and streptavidin/biotin systems,
were tested on the SPCEs. The assay reagents for the biosensor were also optimised prior to its evaluation.
Analytical sensitivity evaluation was carried out using pooled sera, while analytical specificity
evaluation was conducted on a panel of six non-dengue serum samples. Subsequently, diagnostic
sensitivity and specificity evaluation were performed using 144 reference samples. Electrochemical
current signals generated from H2O2 catalysed by HRP-labelled anti-dengue detection antibodies
were measured using the chronoamperometric technique. With a limit of detection (LOD) of 106
serum dilution, the analytical sensitivity of the developed biosensor was 10 times higher than commercial
ELISA. The analytical specificity of this dengue IgM biosensor was 100%. Similarly, the
biosensor’s diagnostic performance was 100% for sensitivity, specificity, positive predictive value
(PPV) and negative predictive value (NPV). These findings suggest that the developed biosensor has
a great potential to be used to diagnose dengue after seroconversion.

Dietary intake of energy and nutrients and its relation to trace element and protein status, as observed in 27 diabetic children and 13 healthy controls are discussed. The diabetic children had consistently higher intakes than the healthy controls in nearly all respects, except for carbohydrate and ascorbic acid. In spite of this, the diabetic children had a significantly lower mean serum magnesium than the healthy controls. It is suggested that hypomagnesemia in diabetic children may be the result of increased urinary loss or diversion of magnesium from normal metabolic pathways in this disease. This review also revealed a significantly higher mean serum selenium level in the diabetic children than in the healthy controls. However, no significant correlation was observed between serum selenium concentrations and protein intake, suggesting that a factor other than protein intake underlay the elevated levels of serum selenium. The diabetic children as a group had significantly lower levels of selected serum proteins than the controls, in spite of a significantly higher intake of protein by the diabetic group. It is suggested that both reduced serum proteins and elevated levels of serum selenium in the diabetic children are an expression of altered metabolism in combination with the effects of current modes of insulin treatment in this disease.

Serum proteins and immunoglobulin (Ig) findings in 119 non-Hodgkin's lymphoma (NHL) patients were analysed. Out of them 96 (81%) patients had B non-Hodgkin lymphoma (B-NHL), and 23 (19%) T-NHL. Indolent type of NHL was more frequent (77 patients, 65%), then aggressive type of NHL (42 patients, 35%). Most patients had normal serum protein concentration, the increased protein concentration was seen in 17% of patients while decreased concentration was noticed in 7% of patients. Hypoalbuminaemia was more frequent (43%) then hyperalbuminaemia (1%). In contrast to albumin, low levels of other protein fractions (alpha1-, alpha2-, and beta-globulin) were rather rare (0.6%, 4%, and 3% of patients, respectively) and high levels were frequent (23%, 37%, and 8%, respectively). Polyclonal hyperimmunoglobulinaemia was more frequent finding than hypoimmunoglobulinaemia. In 29% patients higher IgG level and in 25% patients higher IgA level were found. IgM hypoimmunoglobulinaemia (22%) was more ...