Plasma membrane-generated ROS and their possible contribution to leaf cell growth of cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis>) MSC16 mitochondrial mutant

Reactive oxygen species (ROS) generally regarded as harmful products of oxygenic metabolism causing oxidative stress and cell damage are also important for control and regulation of biological processes. ROS can be generated by various enzymatic activities and removed by an array of ROS-scavenging molecules in the cell. In plants, the generation of ROS initiated by the plasma membrane NADPH oxidase can be used for controlled polymer breakdown leading to cell wall loosening during extension growth. The mosaic (MSC16) mitochondrial mutant of cucumber (Cucumis sativus L.) has marked phenotypic changes, including a slower growth rate which partially may result from disturbed leaf carbon and energy metabolism and ROS/antioxidants equilibrium. Cytochemical localization of H₂O₂ in leaf cells showed lower total level of H₂O₂ particularly in the apoplast of MSC16 leaf cells as compared to WT. The activity of plasma membrane NADPH oxidase (EC 1.6.3.1) was about 30% lower in plasmalemma vesicles isolated from MSC16 leaf tissue as compared to WT. The total foliar ascorbate pool (reduced and oxidized) was about 35% higher in MSC16 compared to WT leaves due to an increased content of the oxidized form. About 3% of the whole-leaf ascorbate was localized in the apoplast but in MSC16 it was considerably more reduced. We conclude that the lower apoplastic ROS content caused by decreased activity of plasma membrane NADPH oxidase and lower amounts of H₂O₂ in the apoplast may also contribute to altered growth of the MSC16 cucumber mutant.     

Release of Metal Ions from Orthodontic Appliances: An In Vitro Study

In this paper, we report the results of an in vitro experiment on the release of metal ions from orthodontic appliances composed of alloys containing iron, chromium, nickel, silicon, and molybdenum into artificial saliva. The concentrations of magnesium, aluminum, silicon, phosphorus, sulfur, potassium, calcium, titanium, vanadium, manganese, iron, cobalt, copper, zinc, nickel, and chromium were significantly higher in artificial saliva in which metal brackets, bands, and wires used in orthodontics were incubated. In relation to the maximum acceptable concentrations of metal ions in drinking water and to recommended daily doses, two elements of concern were nickel (573 vs. 15 μg/l in the controls) and chromium (101 vs. 8 μg/l in the controls). Three ion release coefficients were defined: α, a dimensionless multiplication factor; β, the difference in concentrations (in micrograms per liter); and γ, the ion release coefficient (in percent). The elevated levels of metals in saliva are thought to occur by corrosion of the chemical elements in the alloys or welding materials. The concentrations of some groups of dissolved elements appear to be interrelated.     

Decrease in salivary lactoferrin output in chronically intoxicated alcohol-dependent patients

Salivary lactoferrin is a glycoprotein involved in the elimination of pathogens and the prevention of massive overgrowth of microorganisms that affect oral and general health. A high concentration of lactoferrin in saliva is often considered to be a marker of damage to the salivary glands, gingivitis, or leakage through inflamed or damaged oral mucosa, infiltrated particularly by neutrophils. We conducted a study to determine the effect of chronic alcohol intoxication on salivary lactoferrin concentration and output. The study included 30 volunteers consisting of ten non-smoking male patients after chronic alcohol intoxication (group A), and 20 control nonsmoking male social drinkers (group C) with no history of alcohol abuse. Resting whole saliva was collected 24 to 48 hours after a chronic alcohol intoxication period. Lactoferrin was assessed by enzyme-linked immunosorbent assay. For all participants, the DMFT index (decayed, missing, or filled teeth), gingival index (GI) and papilla bleeding index (PBI) were assessed. The differences between groups were evaluated using the Mann-Whitney U test. We noticed significantly decreased salivary flow (SF) in alcohol dependent patients after chronic alcohol intoxication (A), compared to the control group (C). Although there was no significant difference in salivary lactoferrin concentration between the alcohol dependent group A and the control group C, we found significantly decreased lactoferrin output in group A compared to group C. We found a significant correlation between the amount of daily alcohol use and a decrease in lactoferrin output. There was a significant increase in GI and a tendency of PBI to increase in group A compared to group C. We demonstrated that chronic alcohol intoxication decreases SF and lactoferrin output. The decreased lactoferrin output in persons chronically intoxicated by alcohol may be the result of lactoferrin exhaustion during drinking (due to its alcohol-related lower biosynthesis or higher catabolism) or to decreased function of neutrophils affected by the ethanol. The poorer periodontal state in alcohol dependent persons compared to controls may be a result of lower salivary flow and decreased protection of the oral cavity by lactoferrin.     

Predictive value of ERCC1 single-nucleotide polymorphism in patients receiving platinum-based chemotherapy for locally-advanced and advanced non-small cell lung cancer--a pilot study

Platinum-based chemotherapy is the main type of I-line treatment of advanced and non-operative NSCLC patients without EGFR gene mutation. The excision repair cross-complementation group 1 (ERCC1) is an enzyme that executes the incision of the damaged DNA strand and removes platinum-induced DNA adducts. We investigated whether ERCC1 gene polymorphism has an effect on the response to chemotherapy and survival in 43 patients with NSCLC treated with platinum-based chemotherapy. ERCC1 19007 T>C SNPs were assessed using a PCR-RFLP methods in DNA isolated from peripheral blood lymphocytes. Disease control occurred significantly (p = 0.045) more frequently in patients with CC or CT genotype compared to patients with TT genotype. Median PFS and OS for CC homozygous were 4 and 10.5 months, 4 and 12.5 months for CT heterozygous, but only 0.3 and 1.5 months for TT homozygous patients, respectively. The probability of PFS was significantly higher (HR = 0.438, 95% CI: 0.084-0.881, p = 0.03) and probability of OS was insignificantlyhigher (HR = 0.503, 95% CI: 0.129-1.137, p = 0.084) in patients with CC or CT genotype than in patients with TT genotype. Uncommon TT genotype of ERCC1 19007 T>C polymorphism could predict poor response and shortening of progression free survival in NSCLC patients treated with platinum-based I-line chemotherapy. The analysis of this polymorphism may serve as a promising tool in the qualification of advanced NSCLC patients for appropriate chemotherapy.     

p21-activated kinase improves cardiac contractility during ischemia-reperfusion concomitant with changes in troponin-T and myosin light chain 2 phosphorylation

p21-activated kinase 1 (Pak1) is a serine/threonine kinase that activates protein phosphatase 2a, resulting in the dephosphorylation of cardiac proteins and increased myofilament Ca(2+) sensitivity. Emerging evidence indirectly indicates a role for Pak1 in ischemia-reperfusion (I/R), but direct evidence is lacking. We hypothesize that activation of the Pak1 signaling pathway is a cardioprotective mechanism that prevents or reverses the detrimental effects of ischemic injury by inducing posttranslational modifications in myofilament proteins that ultimately improve cardiac contractility following ischemic insult. In the present study, we subjected ex vivo hearts from wild-type (WT) and Pak1-knockout (KO) mice to 20 min of global cardiac ischemia followed by 30 min of reperfusion. In the absence of Pak1, there was an exacerbation of the increased end-diastolic pressure and reduced left ventricular developed pressure occurring after I/R injury. ProQ analysis revealed an increase in troponin-T phosphorylation at baseline in Pak1-KO hearts compared with WT. Significantly decreased myosin light chain 2 (MLC2) phosphorylation in Pak1-KO hearts compared with WT after I/R injury was confirmed by Western immunoblotting. These data indicate that Pak1-KO hearts have reduced recovery of myocardial performance after global I/R injury concomitant with changes in troponin-T and MLC2 phosphorylation. Finally, a protein-protein association between Pak1 and MLC2, and Pak1 and troponin-T, was determined by coimmunoprecipitation. Thus, results of our study provide a basis for targeting a novel pathway, including Pak1, in the therapies for patients with ischemic events.     

Age-related changes in the mRNA levels of CYP1A1, CYP2B1/2 and CYP3A1 isoforms in rat small intestine

It has been established beyond doubt that, as well as the liver, the small intestine is an important site of first-pass metabolism of numerous drugs, food components and toxic xenobiotics. However, there is not much information available about age-dependent changes of intestinal biotransformation pathways. In the present paper, we evaluated the relationships between intestinal cytochrome P450 complex activity and the age of animals. The study was carried out on male Sprague–Dawley rats (n = 5) from 5 age series: 0.5-, 2-, 4-, 20-, and 28 months old. Animals at every age series were divided into 4 groups: control and three groups of rats treated with the CYP450 specific inducers: phenobarbital, β-naphtoflavone and dexamethasone, respectively. RNA was isolated from intestinal mucosa, and then standard RT-PCR was used for the analysis of CYP1A1, CYP2B1/2 and CYP3A1 mRNA expression. Additionally, the activities of NADPH-cytochrome P450 and NADH-cytochrome b₅ reductases in the microsomal fraction were biochemically estimated. The constitutive intestinal CYP1A1 mRNA expression changes during maturation and aging. Inducibility of CYP1A1 gene was evident in intestinal mucosa at 2-, 4- and 20-month-old rats. A similar pattern of changes was observed for CYP2B1/2 isoforms. CYP3A1 mRNA expression was not detected in small intestine of 2-week-old rats. In matured rats, constitutive intestinal CYP3A1 expression was low, although after induction, significant increases in CYP3A1 mRNA amount were noted in aged individuals. Intestinal activity of both analyzed reductases was lowest in immature rats and highest in 28-month-old animals. In conclusion, the activity of cytochrome P450 complex in rat small intestine was not decreased by the aging processes, so the high rate of oxidative metabolic reactions in intestinal mucosa can be maintained till the advanced life stage.     

Alternative algebraic rate‐integration approach for progress‐curve analysis of enzyme kinetics

A recent article of Zavrel et al. in this journal (Eng. Life Sci. 2010, 10, 191–200) described a comparison of several computer programs for progress‐curve analysis with respect to different computational approaches for parameter estimation. The authors applied both algebraic and dynamic parameter estimations, although they omitted time‐course analysis through the integrated rate equation. Recently, it was demonstrated that progress‐curve analysis through the integrated rate equation can be considered a simple and useful alternative for enzymes that obey the generalized Michaelis–Menten reaction mechanism. To complete this gap, the time‐dependent solution of the generalized Michaelis–Menten equation is here fitted to the progress curves from the Zavrel et al. reference article. This alternative rate‐integration approach for determining the kinetics parameters of Michaelis–Menten‐type enzymes yields the values with the greatest accuracy, as compared with the results obtained by other (algebraic or dynamic) parameter estimations.     

Assessment of significance of features acquired from thyroid ultrasonograms in Hashimoto's disease

Background

Most studies on biodegradable magnesium implants published recently use magnesium-calcium-alloys or magnesium-aluminum-rare earth-alloys. However, since rare earths are a mixture of elements and their toxicity is unclear, a reduced content of rare earths is favorable. The present study assesses the in vivo biocompatibility of two new magnesium alloys which have a reduced content (ZEK100) or contain no rare earths at all (AX30).

Methods

24 rabbits were randomized into 4 groups (AX30 or ZEK100, 3 or 6 months, respectively) and cylindrical pins were inserted in their tibiae. To assess the biodegradation ??CT scans and histological examinations were performed.

Results

The ??CT scans showed that until month three ZEK100 degrades faster than AX30, but this difference is leveled out after 6 months. Histology revealed that both materials induce adverse host reactions and high numbers of osteoclasts in the recipient bone. The mineral apposition rates of both materials groups were high.

Conclusions

Both alloys display favorable degradation characteristics, but they induce adverse host reactions, namely an osteoclast-driven resorption of bone and a subsequent periosteal formation of new bone. Therefore, the biocompatibility of ZEK100 and AX30 is questionable and further studies, which should focus on the interactions on cellular level, are needed.     

Assessment of significance of features acquired from thyroid ultrasonograms in Hashimoto's disease

ABSTRACT: INTRODUCTION: This paper concerns the analysis of the features obtained from thyroid ultrasound images in left and right transverse and longitudinal sections. In the image analysis, the thyroid lobe is treated as a texture for healthy subjects and patients with Hashimoto's disease. The applied methods of analysis and image processing were profiled to obtain 10 features of the image. Then, their significance in the classification was shown.MaterialIn this study, the examined group consisted of 29 healthy subjects aged 18 to 60 and 65 patients with Hashimoto's disease. For each subject, four ultrasound images were taken. They were all in transverse and longitudinal sections of the right and left lobe of the thyroid, which gave 376 images in total. METHOD: 10 different features obtained from each ultrasound image were suggested. The analyzed thyroid lobe was marked automatically or manually with a rectangular element. RESULTS: The analysis of 10 features and the creation for each one of them their own decision tree configuration resulted in distinguishing 3 most significant features. The results of the quality of classification show accuracy above 94% for a non-trimmed decision tree.