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Significant Linear Relation (significant + linear_relation)
Selected AbstractsRegional sympathetic denervation affects the relation between canine local myocardial blood flow and oxygen consumptionEXPERIMENTAL PHYSIOLOGY, Issue 3 2007David J. C. Alders Myocardial blood flow and oxygen consumption are heterogeneously distributed. Perfusion and myocardial oxygen consumption are closely correlated in the normal heart. It is unknown how this metabolism,perfusion relation is influenced by sympathetic denervation. We investigated this question in seven chloralose-anaesthetized dogs, 3,4 weeks after regional sympathetic denervation of the left circumflex coronary artery area of supply of the left ventricle. Measurements were made of local myocardial blood flow (MBF, in ml min,1 (g dry wt),1), measured with microspheres, and myocardial oxygen consumption (, in ,mol min,1 (g dry wt),1) in the same location, calculated from the 13C spectrum of tissue extracts after intracoronary infusion of 3,13C-lactate. Since both innervated and denervated regions are subject to the same arterial pressure, lower blood flow indicates higher resistance. Mean MBF was 5.56 ml min,1 (g dry wt),1 (heterogeneity of 3.47 ml min,1 (g dry wt),1) innervated, 7.48 ml min,1 (g dry wt),1 (heterogeneity of 3.62 ml min,1 (g dry wt),1) denervated (n.s.). Significant linear relations were found between MBF and of individual samples within the innervated and denervated regions. The slopes of these relations were not significantly different, but the adjusted mean was significantly higher in the denervated regions (+1.92 ml min,1 (g dry wt),1, an increase of 38% of the mean MBF at the pooled mean , P= 0.028, ANCOVA). The ratio (in ml ,mol,1) was significantly higher, being 0.296 ± 0.167 ml ,mol,1 in the denervated region compared with the innervated region, 0.216 ± 0.126 ml ,mol,1, P= 0.0182, Mann,Whitney U test. These results indicate that sympathetic tone under chloralose anaesthesia imposes a moderate vasoconstrictive effect in the myocardium that is not detected by comparison of the mean blood flow or resistance. [source] Effects of aging and gender on the spatial organization of nuclei in single human skeletal muscle cellsAGING CELL, Issue 5 2010Alexander Cristea Summary The skeletal muscle fibre is a syncitium where each myonucleus regulates the gene products in a finite volume of the cytoplasm, i.e., the myonuclear domain (MND). We analysed aging- and gender-related effects on myonuclei organization and the MND size in single muscle fibres from six young (21,31 years) and nine old men (72,96 years), and from six young (24,32 years) and nine old women (65,96 years), using a novel image analysis algorithm applied to confocal images. Muscle fibres were classified according to myosin heavy chain (MyHC) isoform expression. Our image analysis algorithm was effective in determining the spatial organization of myonuclei and the distribution of individual MNDs along the single fibre segments. Significant linear relations were observed between MND size and fibre size, irrespective age, gender and MyHC isoform expression. The spatial organization of individual myonuclei, calculated as the distribution of nearest neighbour distances in 3D, and MND size were affected in old age, but changes were dependent on MyHC isoform expression. In type I muscle fibres, average NN-values were lower and showed an increased variability in old age, reflecting an aggregation of myonuclei in old age. Average MND size did not change in old age, but there was an increased MND size variability. In type IIa fibres, average NN-values and MND sizes were lower in old age, reflecting the smaller size of these muscle fibres in old age. It is suggested that these changes have a significant impact on protein synthesis and degradation during the aging process. [source] Spawning habitat and daily egg production of sardine (Sardina pilchardus) in the eastern MediterraneanFISHERIES OCEANOGRAPHY, Issue 4 2006S. SOMARAKIS Abstract Spawning habitats of two eastern Mediterranean sardine, Sardina pilchardus (Walbaum, 1792), stocks (coastal waters of central Aegean and Ionian Seas) are characterized from daily egg production method (DEPM) surveys conducted during the peak of the spawning period. The latter occurs earlier in the Aegean Sea (December) than in the less-productive Ionian Sea (February). Single-parameter quotient analysis showed that the preferred bottom depth for spawning was 40,90 m in both areas but sardine selected sites of increased zooplankton in the Aegean Sea during December and increased fluorescence in the Ionian Sea during February. Estimates of daily egg production (P) and spawning stock biomass (B) were about four times lower for the Ionian Sea (P = 7.81 eggs m,2, B = 3652 tonnes) than the Aegean Sea (P = 27.52 eggs m,2, B = 16 174 tonnes). We suggest that zooplankton biomass might not be sufficient to support sardine reproduction in the highly oligotrophic Ionian Sea where the very small sardine stock may rely on the late-winter phytoplankton bloom. Actively selecting sites with increased zooplankton or phytoplankton and feeding plasticity (the well-known switching from selective particle feeding to non-selective filter feeding in sardines) are interpreted as adaptations to grow and reproduce optimally at varying prey conditions. Despite differences in temperature and productivity regimes, reproductive performance of sardine in the Ionian Sea was very similar to that in the Aegean Sea during the peak of the spawning period. In comparing adult parameters from DEPM applications to Sardina and Sardinops stocks around the world, a highly significant linear relation emerged between mean batch fecundity (F) and mean weight of mature female (W, g) (F = 0.364W, r2 = 0.98). The latter implies that, during the peak of the spawning period, mean relative batch fecundity (eggs g,1) of sardine is fairly constant in contrasting ecosystems around the world. [source] Pulmonary Venous Wedge Pressure Provides an Accurate Assessment of Pulmonary Artery Pressure in Children with a Bidirectional Glenn ShuntJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 5 2003DANIEL H. GRUENSTEIN M.D. Purpose: In circulations with pulsatile pulmonary artery flow the pulmonary venous wedge pressure (PVWp) has been validated as a good estimate of pulmonary artery pressure (PAp), when PAp is low. The purpose of this study was to validate PVWp estimates of PAp in the less-pulsatile pulmonary circulation of children after bidirectional Glenn shunts. Methods: A retrospective study was performed of 22 simultaneous measurements of PVWp and PAp made during 20 catheterizations in 19 children who had undergone bidirectional Glenn procedures. The PAp was measured directly from the branch PA ipsilateral to the side of the PVWp, or in the SVC. Pulmonary resistance (Rp) was calculated with both PAp and PVWp, to assess the impact of PAp estimates on Rp determinations. Results: Patients ranged in age from 5 months to 10.7 years. There were a variety of univentricular cardiac malformations in the study group. Two children had antegrade pulmonary blood flow in addition to a bidirectional Glenn shunt. The mean PAp ranged from 4 to 14 mmHg, while mean PVWp ranged from 3 to 15 mmHg. Mean PVWp never differed from mean PAp by more than 3 mmHg. There was a significant linear relation between mean PAp and PVWp: PAp = 0.86 (PVWp) + 2.0 (R2= 0.89; P < 0.0001). PVWp provided a good approximation of PAp regardless of the presence (n = 2) or absence (n = 19) of antegrade pulmonary flow. There was a good linear correlation between the Rp calculated by both methods (RpPAp = 0.9 (RpVWp) + 0.5; R2= 0.74; P < 0.0001). Conclusion: The mean PVWp provides a close approximation of mean PAp in children with a bidirectional Glenn shunt and provides valuable hemodynamic information in cases where direct PAp measurements are unavailable. (J Interven Cardiol 2003;16:367,370) [source] Prevalence of immunoglobulin E for fungi in atopic childrenCLINICAL & EXPERIMENTAL ALLERGY, Issue 10 2001G. Nolles Background The prevalence of sensitization to fungi in young atopic patients in relation to age and clinical importance is largely unknown. Objective The aim of this study was to investigate the prevalence of sensitization to different fungi in atopic children in relation to age and other aeroallergens. Methods A total of 137 atopic children (male 62%, female 38%; mean age 5 years and 9 months, range 5 months,14 years) were studied. Sera of all patients were routinely tested for total IgE and specific IgE against aeroallergens and milk. Positive sera were also tested for IgE against Alternaria alternata, Aspergillus fumigatus, Cladosporium herbarum and Penicillium chrysogenum, using the Pharmacia Enzyme CAP procedure. Results In this study in atopic children total IgE showed a significant linear relation with age, whereas specific IgE against outdoor fungi, indoor fungi and house dust mite showed significant non-linearity with age. Prevalence of specific IgE for Cladosporium ranked first, followed closely by Aspergillus and Alternaria. Calculation of the sensitization of indoor and outdoor fungi showed maximum prevalence at 7.8 years, followed by lower values at higher ages. A similar significant relation was also found for Alternaria, while this relation was not significant for the other individual fungi. Specific IgE for indoor and outdoor fungi was associated with the presence of specific IgE for aeroallergen and milk. We found that all children aged 4 years and older showed IgE for house dust mite that did not decline with increasing age. Conclusions Sensitization to fungi is prevalent in childhood, with an age-dependent distribution reaching maximum values at 7.7,7.8 years, followed by a decline for all fungal sensitization with increasing age. The importance and relative contribution of fungal sensitization to airway disease, compared with the other allergens, remains to be established. [source] | |||||||||||||