Monocyte and macrophage activation by lipoteichoic Acid is independent of alanine and is potentiated by hemoglobin

Lipoteichoic acids (LTAs) are Gram-positive bacterial cell wall components that elicit mononuclear cell cytokine secretion. Cytokine-stimulating activity is thought to be dependent on retaining a high level of ester-linked D-alanine residues along the polyglycerol phosphate backbone. However, Streptococcus pyogenes LTA essentially devoid of D-alanine caused human and mouse cells to secrete as much IL-6 as LTA with a much higher D-alanine content. Furthermore, hemoglobin (Hb) markedly potentiates the stimulatory effect of various LTAs on mouse macrophages or human blood cells, regardless of their d-alanine content. LTA and Hb appear to form a molecular complex, based on the ability of each to affect the other's migration on native acrylamide gels, their comigration on these gels, and the ability of LTA to alter the absorption spectra of Hb. Because S. pyogenes is known to release LTA and secrete at least two potent hemolytic toxins, LTA-Hb interactions could occur during streptococcal infections and might result in a profound alteration of the local inflammatory response.     

Assessment of the interaction procedure between Pt(IV) prodrug [Pt(5,5′-dmbpy)Cl4 and human serum albumin: Combination of spectroscopic and molecular modeling technique

In this study, a cytotoxic Pt(IV) complex [Pt(5,5′-dmbpy)Cl₄ (5,5′-dmbpy is 5,5′-dimethyl-2,2′-bipyridine) was selected to investigate its affinity to human serum albumin (HSA) by spectroscopy and molecular docking methods. This complex has a bidentate nitrogen donor ligand with four chloride anions attached to a Pt(IV) metal in a distorted octahedral environment. The ?uorescence data showed this complex quench the intrinsic ?uorescence of HSA through a static quenching mechanism. The binding constant (K_b) and the number of binding sites (n) were obtained based on the results of fluorescence measurements. UV–vis, circular dichroism spectroscopy, and three-dimensional fluorescence spectroscopy proved that the Pt(IV) complex could slightly change the secondary structure of protein. Thermodynamic parameters show that the Pt(IV) complex binds to HSA through electrostatic and Vander Waals interactions with one binding site. The molecular docking results confirmed the spectroscopic results and showed that Pt(IV) complex is embedded into subdomain IIA of protein. The aim of this study is to describe the performance of effective anti-cancer drugs when faced with proteins such as HSA.     

Role of circulating soluble CD40 as an apoptotic marker in liver disease

OBJECTIVES: To measure levels of soluble CD40, a laboratory marker of apoptosis in patients with liver disease, determine its origin, and correlate the findings with disease activity and histology. DESIGN: Laboratory research study with comparison group. SETTING: Liver Institute, Laboratory of HLA Typing and Histopathology Department, Rabin Medical Center, Israel. SUBJECTS: One hundred ten patients with liver disease and 20 healthy controls. METHODS: Serum samples were collected from all patients; in addition, paired hepatic and portal vein samples were collected from 23 patients, and bile samples from 5 patients. Soluble CD40 was measured with an enzyme-linked immunosorbent assay. Apoptotic cells in liver tissue were identified by morphological criteria and quantified with the TUNEL assay. RESULTS: Soluble CD40 concentration was significantly higher in patients with liver disease than controls (mean 112.9 +/- 197.2 pg/ml vs. 24.2 +/- 9.1 pg/ml, p = 0.0001), with highest levels in the chronic viral hepatitis group (mean 131.7 +/- 137.5 pg/ml, p = 0.0001). Levels of sCD40 were correlated with serum creatinine, alkaline phosphatase, alpha-feto protein, and the apoptotic index. In the 23 paired samples, CD40 level was higher in the hepatic vein (mean 74.9 +/- 114.5 pg/ml) than the portal vein (mean 51.6 +/- 67.9 pg/ml); it was highly detectable in bile (mean 115.6 +/- 119.6 pg/ml, p = 0.0123). Untreated patients with chronic viral hepatitis (B and C) had higher levels (mean 106.2 +/- 76.5 pg/ml) than treated patients (mean 59.3 +/- 68.6 pg/ml, p = 0.049). CONCLUSIONS: Levels of soluble CD40 increase in different types of liver disease. It probably derives from the liver and is secreted into the bile. Levels correlate with the apoptotic index and are affected by antiviral treatment. Soluble CD40 may serve as a serum marker of apoptosis in liver disease.     

Application of a fluorescent biosensor based‐on magneto‐γ‐Fe2O3–methyldopa nanoparticles for adsorption of human serum albumin

Understanding and controlling the interaction between the polymer methyldopa (2‐amino‐3‐(3,4‐dihydroxyphenyl)‐2‐methyl‐propanoic acid) (PMDP)–γ‐Fe₂O₃ nanoparticles and biological fluids is important if the potential of nanoparticles (NPs) in biomedicine is to be realized. Physicochemical studies on the interactions between proteins and NPs are influenced by the surface properties of the NPs. To identify the effects of the NP surface, interactions between human serum albumin (HSA) and PMDP–γ‐Fe₂O₃ NPs were investigated. Here, the adsorption of HSA onto small (10–30 nm diameter) PMDP–γ‐Fe₂O₃ NPs was quantitatively analyzed using spectroscopic methods. The fluorescence quenching data were checked for the inner‐filter effect, the main confounding factor in the observed quenching. The binding constants, K_a, were calculated at different temperatures, using a nonlinear fit to the experimental data, and the thermodynamic parameters ?H, ?S and ?G were given. The obtained thermodynamic signature suggests that hydrophobic interactions at least are present. This result indicates that the structure of the protein turns from a structureless denatured state at pH 3 into an ordered biologically active native state on addition of PMDP–γ‐Fe₂O₃ NPs. Copyright © 2015 John Wiley & Sons, Ltd.     

Evolutionary Conserved Role of c-Jun-N-Terminal Kinase in CO2-Induced Epithelial Dysfunction

Elevated CO₂ levels (hypercapnia) occur in patients with respiratory diseases and impair alveolar epithelial integrity, in part, by inhibiting Na,K-ATPase function. Here, we examined the role of c-Jun N-terminal kinase (JNK) in CO₂ signaling in mammalian alveolar epithelial cells as well as in diptera, nematodes and rodent lungs. In alveolar epithelial cells, elevated CO₂ levels rapidly induced activation of JNK leading to downregulation of Na,K-ATPase and alveolar epithelial dysfunction. Hypercapnia-induced activation of JNK required AMP-activated protein kinase (AMPK) and protein kinase C-ζ leading to subsequent phosphorylation of JNK at Ser-129. Importantly, elevated CO₂ levels also caused a rapid and prominent activation of JNK in Drosophila S2 cells and in C. elegans. Paralleling the results with mammalian epithelial cells, RNAi against Drosophila JNK fully prevented CO₂-induced downregulation of Na,K-ATPase in Drosophila S2 cells. The importance and specificity of JNK CO₂ signaling was additionally demonstrated by the ability of mutations in the C. elegans JNK homologs, jnk-1 and kgb-2 to partially rescue the hypercapnia-induced fertility defects but not the pharyngeal pumping defects. Together, these data provide evidence that deleterious effects of hypercapnia are mediated by JNK which plays an evolutionary conserved, specific role in CO₂ signaling in mammals, diptera and nematodes.     

The Efficacy of an Immunoisolating Membrane System for Islet Xenotransplantation in Minipigs

Developing a device that protects xenogeneic islets to allow treatment and potentially cure of diabetes in large mammals has been a major challenge in the past decade. Using xenogeneic islets for transplantation is required in light of donor shortage and the large number of diabetic patients that qualify for islet transplantation. Until now, however, host immunoreactivity against the xenogeneic graft has been a major drawback for the use of porcine islets. Our study demonstrates the applicability of a novel immunoprotective membrane that allows successful xenotransplantation of rat islets in diabetic minipigs without immunosuppressive therapy. Rat pancreatic islets were encapsulated in highly purified alginate and integrated into a plastic macrochamber covered by a poly-membrane for subcutaneous transplantation. Diabetic Sinclair pigs were transplanted and followed for up to 90 days. We demonstrated a persistent graft function and restoration of normoglycemia without the need for immunosuppressive therapy. This concept could potentially offer an attractive strategy for a more widespread islet replacement therapy that would restore endogenous insulin secretion in diabetic patients without the need for immunosuppressive drugs and may even open up an avenue for safe utilization of xenogeneic islet donors.     

Duration of diapause in the stem borers, Busseola fusca and Chilo partellus

The duration of diapause in the stem borers Busseola fusca (Fuller) and Chilo partellus (Swinhoe) was studied in South Africa by collecting diapausing larvae from the field throughout winter (April–August). B. fusca larvae emerged as moth around the middle of October regardless of the date of collection and the length of time they were kept in the laboratory under constant 21 °C. C. partellus larvae collected in April–June emerged in November, those collected in July emerged in October, and those collected in August emerged in September. Regardless of the collection date C. partellus started to emerge from diapause earlier and moth emergence lasted up to twice as long as in B. fusca. Under laboratory conditions at 60% RH both borer larvae lost about 50% of their body mass during diapause. When provided with water B. fusca larvae lost about 30% of their body mass and adults emerged 20 days earlier than when kept dry. C. partellus, on the other hand, lost only 13% of their body weight and emerged 34 days earlier. The differences between the two species are discussed in light of different types of diapause; i.e., obligatory diapause in B. fusca and facultative diapause in C. partellus.     

Evaluation of the Validity of Job Exposure Matrix for Psychosocial Factors at Work

Objective

To study the performance of a developed job exposure matrix (JEM) for the assessment of psychosocial factors at work in terms of accuracy, possible misclassification bias and predictive ability to detect known associations with depression and low back pain (LBP).

Materials and Methods

We utilized two large population surveys (the Health 2000 Study and the Finnish Work and Health Surveys), one to construct the JEM and another to test matrix performance. In the first study, information on job demands, job control, monotonous work and social support at work was collected via face-to-face interviews. Job strain was operationalized based on job demands and job control using quadrant approach. In the second study, the sensitivity and specificity were estimated applying a Bayesian approach. The magnitude of misclassification error was examined by calculating the biased odds ratios as a function of the sensitivity and specificity of the JEM and fixed true prevalence and odds ratios. Finally, we adjusted for misclassification error the observed associations between JEM measures and selected health outcomes.

Results

The matrix showed a good accuracy for job control and job strain, while its performance for other exposures was relatively low. Without correction for exposure misclassification, the JEM was able to detect the association between job strain and depression in men and between monotonous work and LBP in both genders.

Conclusions

Our results suggest that JEM more accurately identifies occupations with low control and high strain than those with high demands or low social support. Overall, the present JEM is a useful source of job-level psychosocial exposures in epidemiological studies lacking individual-level exposure information. Furthermore, we showed the applicability of a Bayesian approach in the evaluation of the performance of the JEM in a situation where, in practice, no gold standard of exposure assessment exists.