Pulse waves in prestressed arteries

In order to better understand the effect of initial stress in blood flow in arteries, a theoretical analysis of wave propagation in an initially inflated and axially stretched cylindrical thick shell is investigated. For simplicity in the mathematical analysis, the blood is assumed to be an incompressible inviscid fluid while the arterial wall is taken to be an isotropic, homogeneous and incompressible elastic material. Employing the theory of small deformations superimposed on a large initial field the governing differential equations of perturbed solid motions are obtained in cylindrical polar coordinates. Considering the difficulty in obtaining a closed form solution for the field equations, an approximate power series method is utilized. The dispersion relations for the most general case of this approximation and for the thin tube case are thoroughly discussed. The speeds of waves propagating in an unstressed tube are obtained as a special case of our general treatment. It is observed that the speeds of both waves increase with increasing inner pressure and axial stretch.     

Concentations of copper, Zinc, and magnesium in sera from patients with idiopathic dilated cardiomyopathy

Trace elements are known to have a key role in myocardial metabolism. The accumulation (cobalt, arsenic, copper) or deficiency (selenium, zinc) of trace elements may be responsible for idiopathic dilated cardiomyopathy. We investigated the trace element concentrations (Cu, Zn, Mg) in sera from patients with dilated cardiomyopathy by atomic absorption spectrophotometry. We observed that patients with dilated cardiomyopathies have higher copper and lower zinc concentrations in serum than healthy controls. The magnesium concentrations of patients did not differ significantly from that of control subjects.     

Effect of pioglitazone on the expression of ubiquitin proteasome system and autophagic proteins in rat pancreas with metabolic syndrome

The metabolic syndrome (MetS) and pathologies associated with metabolic dysregulations a worldwide growing problem. Our previous study demonstrated that pioglitazone (PGZ) has beneficial effects on metabolic syndrome associated disturbances in the heart. However, mechanism mediating the molecular alterations of Ubiquitin proteasome system (UPS) and autophagy has not been investigated in rat pancreas with metabolic syndrome. For this reason, we first aimed to detect whether MetS effects on the expression of UPS (p97/VCP, SVIP, Ubiquitin) and autophagic (p62, LC3) proteins in rat pancreas. The second aim of the study was to find impact of pioglitazone on the expression of UPS and autophagic proteins in MetS rat pancreas. To answer these questions, metabolic syndrome induced rats were used as a model and treated with pioglitazone for 2 weeks. Pancreatic tissue injuries, fibrosis and lipid accumulation were evaluated histopathologically in control, MetS and MetS-PGZ groups. Apoptosis and cell proliferation of pancreatic islet cells were assessed in all groups. UPS and autophagic protein expressions of pancreas in all groups were detected by using immunohistochemistry, double-immunfluorescence and Western blotting. Compared with the controls, the rat fed with high sucrose exhibited signs of metabolic syndrome, such as higher body weight, insulin resistance, higher triglyceride level and hyperglycaemia. MetS rats showed pancreatic tissue degeneration, fibrosis and lipid accumulation when their pancreas were examined with Hematoxilen-eozin and Mallory trichrome staining. Metabolic, histopathologic parameters and cell proliferation showed greater improvement in MetS-PGZ rats and pioglitazone decreased apoptosis of islet cells. Moreover, SVIP, ubiquitin, LC3 and p62 expressions were significantly increased while only p97/VCP expression was significantly decreased in MetS-rat pancreas compared to control. PGZ treatment significantly decreased the MetS-induced increases in autophagy markers. Additionally, UPS and autophagy markers were found to colocalizated with insulin and glucagon. Colocalization ratio of UPS markers with insulin showed significant decrease in MetS rats and PGZ increased this ratio, whereas LC3-insulin colocalization displayed significant increase in MetS rats and PGZ reversed this effect. In conclusion, PGZ improved the pancreatic tissue degeneration by increasing the level of p97/VCP and decreasing autophagic proteins, SVIP and ubiquitin expressions in MetS-rats. Moreover, PGZ has an effect on the colocalization ratio of UPS and autophagy markers with insulin.

     

Effect of Cu,Fe, Mn,Ni, and Zn and Bioaccessibilities in the Hazelnuts Growing in Sakarya,Turkey using In-Vitro Gastrointestinal Extraction Method

Biological Trace Element Research - Total concentrations of heavy metals such as Cu, Fe, Mn, Ni, and Zn in different hazelnut samples obtained by different regions of Sakarya city, Turkey were...     

Streptococcal dTDP‐L‐rhamnose biosynthesis enzymes: functional characterization and lead compound identification

Biosynthesis of the nucleotide sugar precursor dTDP‐L‐rhamnose is critical for the viability and virulence of many human pathogenic bacteria, including Streptococcus pyogenes (Group A Streptococcus; GAS), Streptococcus mutans and Mycobacterium tuberculosis. Streptococcal pathogens require dTDP‐L‐rhamnose for the production of structurally similar rhamnose polysaccharides in their cell wall. Via heterologous expression in S. mutans, we confirmed that GAS RmlB and RmlC are critical for dTDP‐L‐rhamnose biosynthesis through their action as dTDP‐glucose‐4,6‐dehydratase and dTDP‐4‐keto‐6‐deoxyglucose‐3,5‐epimerase enzymes respectively. Complementation with GAS RmlB and RmlC containing specific point mutations corroborated the conservation of previous identified catalytic residues. Bio‐layer interferometry was used to identify and confirm inhibitory lead compounds that bind to GAS dTDP‐rhamnose biosynthesis enzymes RmlB, RmlC and GacA. One of the identified compounds, Ri03, inhibited growth of GAS, other rhamnose‐dependent streptococcal pathogens as well as M. tuberculosis with an IC₅₀ of 120–410 µM. Importantly, we confirmed that Ri03 inhibited dTDP‐L‐rhamnose formation in a concentration‐dependent manner through a biochemical assay with recombinant rhamnose biosynthesis enzymes. We therefore conclude that inhibitors of dTDP‐L‐rhamnose biosynthesis, such as Ri03, affect streptococcal and mycobacterial viability and can serve as lead compounds for the development of a new class of antibiotics that targets dTDP‐rhamnose biosynthesis in pathogenic bacteria.     

Purification,biochemical characterization and gene sequencing of a thermostable raw starch digesting α-amylase from Geobacillus thermoleovorans subsp. stromboliensis subsp. nov.

This study reports the purification and biochemical characterization of a raw starch-digesting α-amylase from Geobacillus thermoleovorans subsp. stromboliensis subsp. nov. (strain Pizzo^T). The molecular weight was estimated to be 58 kDa by SDS–PAGE. The enzyme was highly active over a wide range of pH from 4.0–10.0. The optimum temperature of the enzyme was 70°C. It showed extreme thermostability in the presence of Ca²⁺, retaining 50% of its initial activity after 90 h at 70°C. The enzyme efficiently hydrolyzed 20% (w/v) of raw starches, concentration normally used in starch industries. The α-amylase showed an high stability in presence of many organic solvents. In particular the residual activity was of 73% in presence of 15% (v/v) ethyl alcohol, which corresponds to ethanol yield in yeast fermentation process. By analyzing its complete amyA gene sequence (1,542 bp), the enzyme was proposed to be a new α-amylase.     

Biotization of Arabidopsis thaliana with Pseudomonas putida and assessment of its positive effect on in vitro growth

Determination of the optimal inoculation method and concentration to use for plant-bacteria interaction studies is important in many cases, such as the phytoremediation of heavy metals and other toxic compounds in contaminated areas. The aim of this study was to compare different concentrations and times of inoculation of Pseudomonas putida with various growth stages of Arabidopsis thaliana in 14-d in vitro cultures. A significant beneficial impact of the bacterium was detected in the shoot length and root weight of seedlings. The highest shoot length and root fresh and dry weights were detected in 14-d and 2 × 10³ cfu mL⁻¹ inoculated samples. In addition, the increase in root weight could be visualized with crystal violet staining, as relatively more root hair and lateral root formation occurred in seedlings inoculated with moderate concentrations of bacteria, possibly due to the ability of P. putida to produce indole-acetic acid. Moreover, the highest photosynthetic pigment accumulation was obtained with the highest bacterial inoculum (2 × 10⁶ cfu mL⁻¹), which was tested in 0- or 3-d-old seedlings. Rhizospheric bacterial colonization was also visualized with GFP-labeled bacteria by confocal microscopy. These results showed that biotization of A. thaliana with P. putida KT2440 did not cause severe oxidative stress in seedlings, because H₂O₂ accumulation levels together with CAT and POX activities were not significantly induced. Therefore, this strain could be used for several applications based on plant-bacteria interactions.

     

Evaluation of insulin resistance and plasma levels for visfatin and resistin in obese and non-obese patients with polycystic ovary syndrome

This study was designed to evaluate insulin resistance and plasma levels of visfatin and resistin in obese and non-obese patients with polycystic ovary syndrome (PCOS).A total of 37 premenopausal PCOS patients with (n = 18, mean (SD) age: 27.5 (5.7 years) or without obesity (n = 19, mean (SD) age: 23.7 (3.1) years) and healthy volunteers (n = 18, mean (SD) age:29.8 (4.1) years) were included in this study. Data on clinical characteristics, glycemic parameters and lipid parameters were recorded for each subject as were plasma visfatin and resistin levels. Mean (SD) HOMA-IR values were significantly higher in obese PCOS patients (3.4 (1.7)) compared with non-obese PCOS patients (2.0 (1.2), p<0.01) and controls (1.6 (0.8), p<0.01). No significant difference was noted between study groups in terms of plasma resistin (ng/mL) or visfatin (ng/mL) levels. There was no correlation between serum plasma visfatin (r = 0.127, p = 0.407) and resistin (r = -0.096, p = 0.544) levels and HOMA-IR. In conclusion, our findings revealed increased likelihood of metabolic and dyslipidemic manifestations in obese compared to non-obese PCOS patients, while no significant difference was noted in visfatin and resistin levels among PCOS patients in terms of co-morbid obesity and in comparison to controls.