Glucocorticoids in intracellular catabolism of myosin and actin

The catabolic effect of glucocorticoids on the structural proteins of contractile apparatus seems to be realized through the increased alkaline proteinase activity and accelerated synthesis of light enzyme subunits. The administration of large amounts of glucocorticoids increased the excretion of 3-methylhistidine in rats by 60%. Digestion of isolated myofibrils with alkaline proteinase resulted in the degradation of myosin heavy chain and actin. The turnover rate of actin and myosin heavy chain was decreased.     

Effect of glucocorticoids on the turnover rate of actin and myosin heavy and light chains on different types of skeletal muscle fibres

The catabolic action of glucocorticoids on the molecular level of the two main muscular proteins, myosin and actin, was found to depend on the type of muscle fibres. The synthesis rate of actin and myosin heavy chain was decreased in all types of muscle fibres, and in myosin light chain only in the slow-twitch red fibres. The turnover rate of actin and myosin heavy chain was also found decreased in all types of muscle fibres. The myosin light chains turned over more rapidly in dexamethasone-treated than in the control rats in all types of muscle fibres except in the case of the slow-twitch red ones as was shown by single and double isotope methods. Dexamethasone treatment enhanced the urinary 3-methylhistidine excretion in rats by 60%.     

Studies on the macroscopic protonation constants of some alpha-amino acids in ethanol-water mixtures

Both to demonstrate whether the predominant species are dipolar ion or the neutral form and to predict the change of dipolar form to neutral form ratio in ethanol-water mixtures, the macroscopic protonation constants of eight alpha-amino acid (glycine, L-alanine, L-valine, L-leucine, L-phenylalanine, L-serine, L-methionine, and L-isoleucine) were determined potentiometrically in 20-80% (v/v) ethanol-water mixtures at 25 degrees C with an ionic strength of 0.10 M. The calculation of the constants was carried out using a PKAS computer program. The effect of solvent composition on the protonation constants and the dipolar ionic to neutral form ratio of these acids in the mixed solvents are discussed. One can conclude that the dipolar form of amino acids, HA(+/-), dominates in ethanol-water mixtures.     

Diagnostic value of salivary cortisol in children with abnormal adrenal cortex functions

AIMS: It has been shown that the free cortisol level in saliva may reflect plasma free cortisol. The measurement of cortisol in saliva is a simple method, and as such it is important in the pediatric age group. In this research, the diagnostic value of measurement of salivary cortisol (SC) measurement was examined in adrenal insufficiency (AI). METHODS: Fifty-one patients, mean age 10.8 +/- 4.29, who were investigated for possible AI, were included. Basal cortisol levels were below 18 microg/dl. Adrenal function was determined by low-dose ACTH test. During the test, samples for SC were obtained simultaneously with serum samples (at 0-10-20-30-40 min). RESULTS: Mean basal serum cortisol level was 8.21 +/- 4.10 microg/dl (mean +/- SD). Basal SC was correlated to basal serum cortisol (r = 0.64, p < 0.001). A cut-off of 0.94 microg/dl for SC differentiated adrenal insufficient subjects from normals with a sensitivity and specificity of 80 and 77%, respectively. A peak SC less than 0.62 microg/dl defined AI with a specificity of 100%; however, sensitivity was 44%. CONCLUSION: Measurement of SC may be used in the evaluation of AI. It is well-correlated to serum cortisol. Peak SC in low-dose ACTH test can be used to differentiate patients with AI in the initial evaluation of individuals with suspected AI.     

CD34+ cells represent highly functional endothelial progenitor cells in murine bone marrow

Background

Endothelial progenitor cells (EPCs) were shown to have angiogenic potential contributing to neovascularization. However, a clear definition of mouse EPCs by cell surface markers still remains elusive. We hypothesized that CD34 could be used for identification and isolation of functional EPCs from mouse bone marrow.

Methodology/Principal Findings

CD34⁺ cells, c-Kit⁺/Sca-1⁺/Lin⁻ (KSL) cells, c-Kit⁺/Lin⁻ (KL) cells and Sca-1⁺/Lin⁻ (SL) cells were isolated from mouse bone marrow mononuclear cells (BMMNCs) using fluorescent activated cell sorting. EPC colony forming capacity and differentiation capacity into endothelial lineage were examined in the cells. Although CD34⁺ cells showed the lowest EPC colony forming activity, CD34⁺ cells exhibited under endothelial culture conditions a more adherent phenotype compared with the others, demonstrating the highest mRNA expression levels of endothelial markers vWF, VE-cadherin, and Flk-1. Furthermore, a dramatic increase in immediate recruitment of cells to the myocardium following myocardial infarction and systemic cell injection was observed for CD34⁺ cells comparing with others, which could be explained by the highest mRNA expression levels of key homing-related molecules Integrin β2 and CXCR4 in CD34⁺ cells. Cell retention and incorporation into the vasculature of the ischemic myocardium was also markedly increased in the CD34⁺ cell-injected group, giving a possible explanation for significant reduction in fibrosis area, significant increase in neovascularization and the best cardiac functional recovery in this group in comparison with the others.

Conclusion

These findings suggest that mouse CD34⁺ cells may represent a functional EPC population in bone marrow, which could benefit the investigation of therapeutic EPC biology.     

Tau-dependent microtubule disassembly initiated by prefibrillar beta-amyloid

Alzheimer's Disease (AD) is defined histopathologically by extracellular beta-amyloid (Abeta) fibrils plus intraneuronal tau filaments. Studies of transgenic mice and cultured cells indicate that AD is caused by a pathological cascade in which Abeta lies upstream of tau, but the steps that connect Abeta to tau have remained undefined. We demonstrate that tau confers acute hypersensitivity of microtubules to prefibrillar, extracellular Abeta in nonneuronal cells that express transfected tau and in cultured neurons that express endogenous tau. Prefibrillar Abeta42 was active at submicromolar concentrations, several-fold below those required for equivalent effects of prefibrillar Abeta40, and microtubules were insensitive to fibrillar Abeta. The active region of tau was localized to an N-terminal domain that does not bind microtubules and is not part of the region of tau that assembles into filaments. These results suggest that a seminal cell biological event in AD pathogenesis is acute, tau-dependent loss of microtubule integrity caused by exposure of neurons to readily diffusible Abeta.     

Hyberbaric oxygen increases atresia in normal &; steroid induced PCO rat ovaries

Background  

In this study, we investigated the effect of hyperbaric oxygen therapy (HBOT) on the morphology of estradiol valerate (EV) induced polycystic ovary (PCO) to find a new treatment modality for improvement of PCO.     

Inactivation and injury of Escherichia coli O157:H7 and Staphylococcus aureus by pulsed electric fields

Two pathogenic microorganisms Escherichia coli O157:H7 and Staphylococcus aureus, suspended in peptone solution (0.1% w/v) were treated with 12, 14, 16 and 20 kV/cm electric field strengths with different pulse numbers up to 60 pulses. Pulsed electric field (PEF) treatment at 20 kV/cm with 60 pulses provided nearly 2 log reduction in viable cell counts of E. coli O157:H7 and S. aureus. S. aureus cells were slightly more resistant than E.coli O157:H7 cells. The results related to the effect of initial cell concentration of E. coli O157:H7 on the PEF inactivation showed that more inactivation was obtained by decreasing initial cell concentration. Any possible injury by PEF was also investigated after applying 20 kV/cm electric field to the microorganisms. As a result, it was determined that there was 35.92 to 43.36% injury in E. coli O157:H7 cells, and 17.26 to 30.86% injury in S. aureus cells depending on pulse number. The inactivation results were also described by a kinetic model.     

Biosynthesis of silver nanoparticles using novel Bacillus sp. SBT8

Biosynthesis of silver nanoparticles (AgNPs) using microorganisms is an important application of nanobiotechnology and green chemistry because of interest by pharmaceutical and food manufacturers. In this study, biosynthesis of AgNPs by a novel Bacillus strain isolated from a soil sample from Sakarya district in Turkey was investigated. Biosynthesis was performed using cell-free supernatant of the bacterium following 24?h growth. Effects of varying AgNO₃ concentration (1–10?mM), pH (5–10), and temperature (30–40°C) on the synthesis of AgNPs were determined. Formation of AgNPs was monitored by UV–VIS spectroscopy. Field emission scanning electron microscopy was used to compare morphologies among the various culture conditions. The peaks created by surface plasmon resonance (SPR) of metals were obtained only at 4 and 6?mM AgNO₃ concentrations and the maximum concentration for the biosynthesis was observed at 6?mM. The highest yield was achieved at pH 10 and larger nanoparticles were obtained at this pH. The optimum temperatures for biosynthesis were 33 and 37°C. Fourier transform infrared spectroscopy analysis and transmission electron microcopy images confirmed that the proteins served as capping. Energy-dispersive spectroscopy analysis validated the formation of AgNPs. AgNPs exhibited antibacterial activity toward Gram-positive and Gram-negative pathogens.     

PROGRESS STUDY: Progression of chronic kidney disease in children and heat shock proteins

Various molecular and cellular processes are involved in renal fibrosis, such as oxidative stress, inflammation, endothelial cell injury, and apoptosis. Heat shock proteins (HSPs) are implicated in the progression of chronic kidney disease (CKD). Our aim was to evaluate changes in urine and serum HSP levels over time and their relationships with the clinical parameters of CKD in children. In total, 117 children with CKD and 56 healthy children were examined. The CKD group was followed up prospectively for 24 months. Serum and urine HSP27, HSP40, HSP47, HSP60, HSP70, HSP72, and HSP90 levels and serum anti-HSP60 and anti-HSP70 levels were measured by ELISA at baseline, 12 months, and 24 months. The urine levels of all HSPs and the serum levels of HSP40, HSP47, HSP60, HSP70, anti-HSP60, and anti-HSP70 were higher at baseline in the CKD group than in the control group. Over the months, serum HSP47 and HSP60 levels steadily decreased, whereas HSP90 and anti-HSP60 levels steadily increased. Urine HSP levels were elevated in children with CKD; however, with the exception of HSP90, they decreased over time. In conclusion, our study demonstrates that CKD progression is a complicated process that involves HSPs, but they do not predict CKD progression. The protective role of HSPs against CKD may weaken over time, and HSP90 may have a detrimental effect on the disease course.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12192-021-01239-9.