Non linear anthropometric predictors in swimming

In this paper we have tried to identify the significance and character of the linear and non-linear relations between simple anthropometric predictors: body height (BH), body weight (BW), and body mass index, and swimming performance: freestyle swimming 50 (FS50) and 400 meters (FS400), in a sample of young (15 years old on average) male (N = 40) and female (N = 28) swimmers. Linear (general model: y = a+bx) and nonlinear regression (general model: y = a+bx+cx2) were calculated simultaneously. Morphological variables are a significantly better predictor of the FS50 in males (BH mostly), and FS400 in females (BW mostly). This study emphasized some of the main advantages in the nonlinear regression calculation (including an interpretation of the relationships at a more superior level), and consequently allowed a precise anthropometric modeling in swimming using simple and easily measurable variables. For example, the best results in FS400 can be expected for the subjects that are average in BW (which guarantees solid muscle mass--the generator of force), but above average in BH (because of the physical law of lever). In conclusion, nonlinear regressions allow one to define the real nature of the relationships between variables, but only if compared with the linear ones. Additionally, this study emphasized one of the most important factors in defining possible specification-equation (e.g. structure of the influence of the different dimensions on the sport achievement) in different sports. In short, it underlines the importance of sampling the appropriate sample of the subject--highly skilled athletes exclusively.     

Decomposition of tensiomyogram and comparison with torque twitch responses after post-activation potentiation

Objectives:This study evaluates the effect of post-activation potentiation (PAP) after 5x5s maximal voluntary isometric contractions (activation stimulus, AS) on tensiomyography (TMG) and torque twitch contractile parameters of vastus lateralis (VL) and medialis (VM), respectively. Further, we validated the decomposition of TMG response to separate responses of three fiber types.Methods:15 healthy individuals participated in this study (40% women; age 19±2.3 years). A decomposition of VL TMG response was done after optimal fitting of three exponential curves.Results:We found main effects in contraction time (Tc) for muscle, method and time. Furthermore, we found interactions between muscle*method, method*time and muscle*method*time. Compared to PRE AS, we found shorter TMG Tc in VL and VM during the first two minutes after AS. Torque Tc remained unchanged in VL, while it increased in VM within 30 seconds after AS. A decomposition of VL TMG response confirmed PAP effects being present only in decomposed type IIb muscle fibers.Conclusion:The TMG is a sensitive method to detect PAP effects with a sensor mounted directly above the muscle belly. After the decomposition of the TMG signal to three separate muscle fiber phenotypes, we provided a non-invasive insight in the contribution of each muscle fiber phenotype to the PAP of the whole muscle.     

Effects of war aggression in Croatia on some forms and manifestations of breast cancer

The aim of this study was to determine the differences in epidemiological and clinical manifestations of breast cancer in time of war in Croatia and in peacetime before and after the war, in the defined population of Pozesko-Slavonska County. The methods used in this study were the evaluation of relative predictive value of variables by means of chi 2-test and the analysis of variance, while the survival studies were tested by Long Rank test according to Kaplan-Meier analysis of survival. This work encompasses 660 patients who had breast cancer. The differences between three time periods were evaluated: the war period (1991-1995), and two control periods: before the war (1981-1990) and after the war (1996-2000). The patients were grouped by age, localization of tumor and survival. During the war period the patients were, on the average, 4.2 years younger than those who acquired the disease in control periods, and the mean age of patients was between 50 and 59 years (36.5% of patients). Although the difference in tumor distribution by sides (left or right breast) and quadrants was statistically significant (war period vs. control periods; p < 0.001), there was no statistically significant difference in the survival of patients according to the results of Kaplan-Meier analysis of localization of tumor (p > 0.05). The length of survival in terms of age of patients in time of surgical procedure was significantly different (p < 0.001). This study confirms the effects of war on some epidemiological and clinical manifestation of breast cancer in the defined population of Pozesko-Slavonska County.     

Concomitant reconstitution of TraI-catalyzed DNA transesterase and DNA helicase activity in vitro

TraI protein of plasmid R1 possesses two activities, a DNA transesterase and a highly processive 5'-3' DNA helicase, which are essential for bacterial conjugation. Regulation of the functional domains of the enzyme is poorly understood. TraI cleaves supercoiled oriT DNA with site and strand specificity in vitro but fails to initiate unwinding from this site (nic). The helicase requires an extended region of adjacent single-stranded DNA to enter the duplex, yet interaction of purified TraI with oriT DNA alone or as an integral part of the IncF relaxosome does not melt sufficient duplex to load the helicase. This study aims to gain insights into the controlled initiation of both TraI-catalyzed activities. Linear double-stranded DNA substrates with a central region of sequence heterogeneity were used to trap defined lengths of R1 oriT sequence in unwound conformation. Concomitant reconstitution of TraI DNA transesterase and helicase activities was observed. Efficient helicase activity was measured on substrates containing 60 bases of open duplex but not on substrates containing < or =30 bases in open conformation. The additional presence of auxiliary DNA-binding proteins TraY and Escherichia coli integration host factor did not stimulate TraI activities on these substrates. This model system offers a novel approach to investigate factors controlling helicase loading and the directionality of DNA unwinding from nic.     

Heat shock protein-GP96 as an innate sensor of damage and activator of autoreactive NKT and regulatory T cells during liver regeneration

Tissue disintegration after injury leads, in the endoplasmic reticulum (ER), to activation of adaptive pathways known as the ER stress response. It is directed to the correction of unfolded proteins and to the activation of proteasome-dependent ER-associated degradation of the misfolded proteins, but induces also a rapid activation of natural and adaptive immunity, since a ER resident heat shock protein-gp96 acts not only as a molecular chaperone, but also as a strong adjuvant, able to cross-present the antigenic peptides onto MHC class I or MHC class II pathways. Analyzing its potential role in processes of normal growth, in mice subjected to 1/3 partial hepatectomy (pHx) we determined the tissue expression of gp96 protein and mRNA in regenerating liver, thymus and spleen, determining simultaneously the phenotypic profile and spontaneous cytotoxic activity of intrahepatic and splenic mononuclear lymphatic cells (MNLC) against NKT- and NK-cells sensitive targets (syngeneic thymocytes and YAC-1) in wild, perforin and FasL deficient mice. The data have shown that pHx induces fast overexpression of gp96 protein and mRNA in hepatocytes, spleen and thymus, with accumulation of CD3intermediate/NK1.1+/CD69+ cells (liver) and Foxp3+CD4+CD25+ cells (liver and thymus). Simultaneously, intrahepatic MNLC acquired the FasL-dependent cytotoxic potential against NKT-sensitive targets and both, intrahepatic and splenic MNLC, acquired the perforin-dependent cytotoxic potential against NK-sensitive targets, implying that during the disturbance of morphostasis gp96 serves as a natural adjuvant for chaperoning antigenic self peptides into the immune surveillance pathways, resulting in activation of autoreactive NKT and regulatory cells, as well as NK cells. Moreover, cell cycle analysis revealed that G2+M phase of regenerating hepatocytes in PKO mice was translocated from the 1st to the 7th p. o. day, as well as that hepatocytes from FasL deficient mice were arrested in G0/G1 phase.     

Laparoscopic abdominal cysts fenestration using harmonic scalpel

The use of ultrasonically activated scalpel for tissue cutting and coagulation is a potential replacement for electrosurgery, which can be related to different complications. Its working principle is to transform the electric power into the mechanical longitudinal movement of the working part of the instrument, by a piezoelectric transducer situated in the hand piece. Between October 2000 and June 2004, six patients with abdominal cysts were treated by laparoscopy, using the harmonic scalpel. The average age was 40.8 (ranging from 15-60) years. Laparoscopic abdominal cyst fenestration was performed in five patients, and laparoscopic cholecystectomy and abdominal cyst fenestration were done in one patient during the same operation. The average duration of the operation was 40 (ranging from 25-70) minutes and hospital stay was 2.8 (ranging from 1-5) days. Laparoscopic abdominal cyst fenestration using the harmonic scalpel is a safe and successful operation, with good results including all the advantages of the minimally invasive surgery.     

The MicroArray Quality Control (MAQC) project shows inter- and intraplatform reproducibility of gene expression measurements

Over the last decade, the introduction of microarray technology has had a profound impact on gene expression research. The publication of studies with dissimilar or altogether contradictory results, obtained using different microarray platforms to analyze identical RNA samples, has raised concerns about the reliability of this technology. The MicroArray Quality Control (MAQC) project was initiated to address these concerns, as well as other performance and data analysis issues. Expression data on four titration pools from two distinct reference RNA samples were generated at multiple test sites using a variety of microarray-based and alternative technology platforms. Here we describe the experimental design and probe mapping efforts behind the MAQC project. We show intraplatform consistency across test sites as well as a high level of interplatform concordance in terms of genes identified as differentially expressed. This study provides a resource that represents an important first step toward establishing a framework for the use of microarrays in clinical and regulatory settings.     

Cholesterol-depletion corrects APP and BACE1 misstrafficking in NPC1-deficient cells

Cholesterol accumulation in Niemann-Pick type C disease (NPC) causes increased levels of the amyloid-precursor-protein C-terminal fragments (APP-CTFs) and intracellular amyloid-β peptide (Aβ), the two central molecules in Alzheimer's disease (AD) pathogenesis. We previously reported that cholesterol accumulation in NPC-cells leads to cholesterol-dependent increased APP processing by β-secretase (BACE1) and decreased APP expression at the cell surface (Malnar et al. Biochim Biophys Acta. 1802 (2010) 682-691.). We hypothesized that increased formation of APP-CTFs and Aβ in NPC disease is due to cholesterol-mediated altered endocytic trafficking of APP and/or BACE1. Here, we show that APP endocytosis is prerequisite for enhanced Aβ levels in NPC-cells. Moreover, we observed that NPC cells show cholesterol dependent sequestration and colocalization of APP and BACE1 within enlarged early/recycling endosomes which can lead to increased β-secretase processing of APP. We demonstrated that increased endocytic localization of APP in NPC-cells is likely due to both its increased internalization and its decreased recycling to the cell surface. Our findings suggest that increased cholesterol levels, such as in NPC disease and sporadic AD, may be the upstream effector that drives amyloidogenic APP processing characteristic for Alzheimer's disease by altering endocytic trafficking of APP and BACE1.     

Hybrid modeling approach to on-line estimation of yeast biomass concentration in industrial bioreactor

The industrial fed-batch yeast cultivation process has been divided into four different metabolic phases (adaptation, carbon limited, oxygen limited and maturation) by a neuro-fuzzy classification model that consists of 4 applied linguistic rules on 2 state variables: oxygen uptake rate and liquid volume. The membership functions have been automatically adapted by this fuzzy perceptron, i.e., by a supervised learning algorithm initialized by prior operator's knowledge. Process compartmentalization has made easier and more realistic a subsequent state estimation of the biomass concentration with separate artificial neural networks combined with balance equations. Static networks with local recurrent memory structures were used, and the inputs were standard cultivation state variables: respiratory quotient, molasses feed rate, ethanol concentration, etc. This hybrid approach is generally applicable to state estimation or prediction when different sources of process information and knowledge have to be integrated.