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Selected AbstractsCirculatory effects of apnoea in elite breath-hold diversACTA PHYSIOLOGICA, Issue 1 2009F. Joulia Abstract Aim:, Voluntary apnoea induces several physiological adaptations, including bradycardia, arterial hypertension and redistribution of regional blood flows. Elite breath-hold divers (BHDs) are able to maintain very long apnoea, inducing severe hypoxaemia without brain injury or black-out. It has thus been hypothesized that they develop protection mechanisms against hypoxia, as well as a decrease in overall oxygen uptake. Methods:, To test this hypothesis, the apnoea response was studied in BHDs and non-divers (NDs) during static and dynamic apnoeas (SA, DA). Heart rate, arterial oxygen saturation (SaO2), and popliteal artery blood flow were recorded to investigate the oxygen-conserving effect of apnoea response, and the internal carotid artery blood flow was used to examine the mechanisms of cerebral protection. Results:, The bradycardia and peripheral vasoconstriction were accentuated in BHDs compared with NDs (P < 0.01), in association with a smaller SaO2 decrease (,2.7% vs. ,4.9% during SA, P < 0.01 and ,6% vs. ,11.3% during DA, P < 0.01). Greater increase in carotid artery blood flow was also measured during apnoea in BHDs than in controls. Conclusion:, These results confirm that elite divers present a potentiation of the well-known apnoea response in both SA and DA conditions. This response is associated with higher brain perfusion which may partly explain the high levels of world apnoea records. [source] Is adiposity across life associated with subsequent hysterectomy risk?BJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 2 2008Findings from the 1946 British birth cohort study Objective, To examine the associations between adiposity at time points from early life onwards and subsequent hysterectomy risk. Design, Prospective birth cohort study. Setting, England, Scotland and Wales. Population, Women from the Medical Research Council National Survey of Health and Development study, with complete data on hysterectomy status (n= 1790). Methods, Survival analysis methods were used to examine the associations between body mass index at time points across life and subsequent hysterectomy rates. Main outcome measure, Self-reported hysterectomy with or without oophorectomy. Results, From 20 years onwards, those women who were classified as underweight had lower hysterectomy rates, and from 36 years onwards, those women who were overweight had higher hysterectomy rates than those who were normal weight. Women who were obese in adolescence and early adulthood had lower rates of hysterectomy than those who were normal weight, although numbers categorised as obese at these ages were small. Women who were obese in later adulthood had higher subsequent rates of hysterectomy. Greater increases in weight between ages 36 and 53 years were associated with higher rates of hysterectomy in later adulthood. These results were not explained by parity, age at menarche or socio-economic position. Conclusions, These results suggest that variation in hysterectomy rates may be partially explained by variation in adiposity, and so with the recent changes in levels of overweight and obesity in populations, there may be increasing demand for gynaecological treatments in the future. [source] Overload-induced skeletal muscle extracellular matrix remodelling and myofibre growth in mice lacking IL-6ACTA PHYSIOLOGICA, Issue 4 2009J. P. White Abstract Aim:, Overloading healthy skeletal muscle produces myofibre hypertrophy and extracellular matrix remodelling, and these processes are thought to be interdependent for producing muscle growth. Inflammatory cytokine interleukin-6 (IL-6) gene expression is induced in overloaded skeletal muscle, and the loss of this IL-6 induction can attenuate the hypertrophic response to overload (OV). Although the OV induction of IL-6 in skeletal muscle may be an important regulator of inflammatory processes and satellite cell proliferation, less is known about its role in the regulation of extracellular matrix remodelling. The purpose of the current study was to examine if OV-induced extracellular matrix remodelling, muscle growth, and associated gene expression were altered in mice that lack IL-6, when compared with wild-type mice. Methods:, Male C57/BL6 (WT) and C57/BL6 × IL-6,/, (IL-6,/,) mice (10 weeks of age) were assigned to either a sham control or synergist ablation OV treatments for 3, 21 or 56 days. Result:, Plantaris muscle mass increased 59% in WT and 116% in IL-6,/, mice after 21 day OV. Myofibre CSA was also increased by 21 day OV in both WT and IL-6,/, mice. OV induced a twofold greater increase in the volume of non-contractile tissue in IL-6,/, muscle compared to WT. OV also induced a significantly greater accumulation of hydroxyproline and procollagen-1 mRNA in IL-6,/, muscle, when compared with WT muscle after 21 day OV. Transforming growth factor-, and insulin-like growth factor-1 mRNA expression were also induced to a greater extent in IL-6,/, muscle when compared with WT muscle after 21 day OV. There was no effect of IL-6 loss on the induction of myogenin, and cyclin D1 mRNA expression after 3 day OV. However, MyoD mRNA expression in 3 day OV IL-6,/, muscle was attenuated when compared with WT OV mice. Conclusion:, IL-6 appears to be necessary for the normal regulation of extracellular matrix remodelling during OV-induced growth. [source] Comparing hormonal and symptomatic responses to experimental hypoglycaemia in insulin- and sulphonylurea-treated Type 2 diabetesDIABETIC MEDICINE, Issue 7 2009P. Choudhary Abstract Aims, Patients with diabetes rely on symptoms to identify hypoglycaemia. Previous data suggest patients with Type 2 diabetes develop greater symptomatic and hormonal responses to hypoglycaemia at higher glucose concentrations than non-diabetic controls and these responses are lowered by insulin treatment. It is unclear if this is as a result of insulin therapy itself or improved glucose control. We compared physiological responses to hypoglycaemia in patients with Type 2 diabetes patients treated with sulphonylureas (SUs) or insulin (INS) with non-diabetic controls (CON). Methods, Stepped hyperinsulinaemic hypoglycaemic clamps were performed on 20 subjects with Type 2 diabetes, 10 SU-treated and 10 treated with twice-daily premixed insulin, and 10 age- and weight-matched non-diabetic controls. Diabetic subjects were matched for diabetes duration, glycated haemoglobin (HbA1c) and hypoglycaemia experience. We measured symptoms, counterregulatory hormones and cognitive function at glucose plateaux of 5, 4, 3.5, 3 and 2.5 mmol/l. Results, Symptomatic responses to hypoglycaemia occurred at higher blood glucose concentrations in SU-treated than INS-treated patients [3.5 (0.4) vs. 2.6 (0.5) mmol/l SU vs. INS; P = 0.001] or controls [SU vs. CON 3.5 (0.4) vs. 3.0 (0.6) mmol/l; P = 0.05]. They also had a greater increase in symptom scores at hypoglycaemia [13.6 (11.3) vs. 3.6 (6.1) vs. 5.1 (4.3) SU vs. INS vs. CON; P = 0.017]. There were no significant differences in counterregulatory hormone responses or impairment of cognitive function among groups. Conclusions, Sulphonylurea-treated subjects are more symptomatic of hypoglycaemia at a higher glucose level than insulin-treated subjects. This may protect them from severe hypoglycaemia but hinder attainment of glycaemic goals. [source] Scale dependence of diversity measures in a leaf-litter ant assemblageECOGRAPHY, Issue 2 2004Maurice Leponce A reliable characterization of community diversity and composition, necessary to allow inter-site comparisons and to monitor changes, is especially difficult to reach in speciose invertebrate communities. Spatial components of the sampling design (sampling interval, extent and grain) as well as temporal variations of species density affect the measures of diversity (species richness S, Buzas and Gibson's evenness E and Shannon's heterogeneity H). Our aim was to document the small-scale spatial distribution of leaf litter ants in a subtropical dry forest of the Argentinian Chaco and analyze how the community characterization was best achieved with a minimal sampling effort. The work was based on the recent standardized protocol for collecting ants of the leaf litter ("A.L.L.": 20 samples at intervals of 10 m). To evaluate the consistency of the sampling method in time and space, the selected site was first subject to a preliminary transect, then submitted after a 9-month interval to an 8-fold oversampling campaign (160 samples at interval of 1.25 m). Leaf litter ants were extracted from elementary 1 m2 quadrats with Winkler apparatus. An increase in the number of samples collected increased S and decreased E but did not affect much H. The sampling interval and extent did not affect S and H beyond a distance of 10 m between samples. An increase of the sampling grain had a similar effect on S than a corresponding increase of the number of samples collected, but caused a proportionaly greater increase of H. The density of species m,2 varied twofold after a 9-month interval; the effect on S could only be partially corrected by rarefaction. The measure of species numerical dominance was little affected by the season. A single standardized A.L.L. transect with Winkler samples collected <45% of the species present in the assemblage. All frequent species were included but their relative frequency was not always representative. A log series distribution of species occurrences was oberved. Fisher's , and Shannon's H were the most appropriate diversity indexes. The former was useful to rarefy or abundify S and the latter was robust against sample size effects. Both parametric and Soberón and Llorente extrapolation methods outperformed non-parametric methods and yielded a fair estimate of total species richness along the transect, a minimum value of S for the habitat sampled. [source] Vitamin D receptor FokI genotype influences bone mineral density response to strength training, but not aerobic trainingEXPERIMENTAL PHYSIOLOGY, Issue 4 2005Karma M. Rabon-Stith To determine the influence of the vitamin D receptor (VDR) gene FokI and BsmI genotype on bone mineral density response to two exercise training modalities, 206 healthy men and women (50,81 years old) were studied before and after ,5,6 months of either aerobic exercise training (AT) or strength training (ST). A totla of 123 subjects completed AT (51 men, 72 women) and 83 subjects completed ST (40 men, 43 women). DNA was extracted from blood samples of all subjects and genotyping was performed at the VDR FokI and BsmI locus to determine its association to training response. Total body, greater trochanter and femoral neck bone mineral density (BMD) were measured before and after both training programmes using dual-energy X-ray absorptiometry. VDR BsmI genotype was not significantly related to BMD at baseline or after ST or AT. However, VDR FokI genotype was significantly related to ST- but not AT-induced changes in femoral neck BMD (P < 0.05). The heterozygotes (Ff) in the ST group approached a significantly greater increase in femoral neck BMD (P= 0.058) compared to f homozygotes. There were no significant genotype relationships in the AT group. These data indicate that VDR FokI genotype may influence femoral neck BMD response to ST, but not AT. [source] Parental Separation and Children's Behavioral/Emotional Problems: The Impact of Parental Representations and Family ConflictFAMILY PROCESS, Issue 1 2010STEPHANIE STADELMANN PH.D. In this longitudinal study, we examine whether the effect of parental separation on kindergarten children's behavioral/emotional problems varies according to the level of family conflict, and children's parental representations. One hundred and eighty seven children were assessed at ages 5 and 6. Family conflict was assessed using parents' ratings. Children's parental representations were assessed using a story-stem task. A multiinformant approach (parent, teacher, child) was employed to assess children's behavioral/emotional problems. Bivariate results showed that separation, family conflict, and negative parental representations were associated with children's behavioral/emotional problems. However, in multivariate analyses, when controlling for gender and symptoms at age 5, we found that children of separated parents who showed negative parental representations had a significantly greater increase in conduct problems between 5 and 6 than all other children. In terms of emotional symptoms and hyperactivity, symptoms at 5 and (for hyperactivity only) gender were the only predictors for symptoms 1 year later. Our results suggest that kindergarten children's representations of parent-child relationships moderate the impact of parental separation on the development of conduct problems, and underline play and narration as a possible route to access the thoughts and feelings of young children faced with parental separation. RESUMEN En este estudio longitudinal analizamos si el efecto de la separación parental sobre los problemas emocionales y conductuales de los niños de primer grado varía según el nivel de conflicto familiar y las representaciones parentales de los niños. Se evaluó a ciento ochenta y siete niños de 5 y 6 años. El conflicto familiar se evaluó utilizando valoraciones de los padres. Las representaciones parentales de los niños se evaluaron mediante una tarea basada en relatos. Se empleó un enfoque multi-informante (padre, maestro, niño) para evaluar los problemas conductuales y emocionales de los niños. Los resultados bivariables demostraron que la separación, el conflicto familiar y las representaciones parentales negativas estuvieron asociadas con problemas conductuales y emocionales en los niños. Sin embargo, en análisis multivariables, cuando se controló el género y los síntomas a los 5 años, descubrimos que los niños de padres separados que demostraron representaciones parentales negativas tuvieron un aumento mucho mayor en problemas de conducta entre los 5 y los 6 años que todos los demás niños. En cuanto a síntomas emocionales e hiperactividad, los síntomas a los 5 años (para hiperactividad solamente) y el género fueron los únicos predictores de síntomas un año después. Nuestros resultados sugieren que las representaciones de los niños de primer grado de las relaciones entre padres y niños moderan el impacto que tiene la separación parental sobre el desarrollo de problemas de conducta. Además, subrayan el juego y la narración como un posible camino para acceder a los pensamientos y sentimientos de los niños que enfrentan la separación de sus padres. Palabras clave: niños de primer grado; separación parental; representaciones parentales; conflicto familiar; problemas conductuales y emocionales [source] Caregiver Depressive Symptoms and Observed Family Interaction in Low-Income Children with Persistent AsthmaFAMILY PROCESS, Issue 1 2008MARIANNE CELANO PH.D. This study examined the relationship between caregiver depressive symptoms and observed parenting behaviors and family processes during interactions among 101 urban, low-income Africtan American families with children with persistent asthma. Caregivers (primarily female) were assessed on four dimensions (i.e., warmth/involvement, hostility, consistent discipline, relationship quality) in three videotaped interaction tasks (loss, conflict, cohesion). The results indicated that increased depressive symptoms were significantly associated with lower warmth/involvement and synchrony scores and greater hostility scores during the loss and conflict tasks. In the total sample, the highest levels of hostility and the lowest levels of warmth/involvement were found for the conflict task; nevertheless, caregivers with moderate/severe depressive symptoms showed a significantly greater increase in hostility from the loss to the conflict task than caregivers with minimal/mild depressive symptoms. The findings highlight the salience of considering task content in family observational process research to expand our understanding of depressed and nondepressed caregivers' abilities to modulate appropriately their behaviors and affect across various family interactions. Implications for improving asthma management for low-income children with persistent asthma are discussed, including the utility of multidisciplinary interventions that combine asthma education with family therapy. RESUMEN Síntomas de depresión en los responsables de los niños e interacción familiar observada en niños de familias de bajos ingresos que padecen asma crónica Este estudio examinó la relación entre los síntomas de depresión de los responsables de los niños y los comportamientos paternos y dinámicas familiares observados durante interacciones entre 101 familias afronorteamericanas, urbanas y de bajos recursos, con niños que padecen asma crónica. Los responsables de los niños (la mayoría mujeres) fueron evaluados en base a cuatro criterios: calidez/implicación, hostilidad, disciplina constante, y calidad de la relación) en tres tareas de interacción grabadas en cinta de video (pérdida, conflicto y cohesión). Los resultados demostraron que el aumento de los síntomas de depresión estaban relacionados de forma significativa con una menor puntuación en calidez/implicación y comprensión mutua, y una mayor puntuación en hostilidad durante las tareas de pérdida y conflicto. En la muestra total, los mayores niveles de hostilidad y menores niveles de calidez/implicación se encontraron en la tarea de conflicto; sin embargo, los responsables con síntomas de depresión de moderados a severos mostraron un aumento mucho mayor de la hostilidad, de la tarea de pérdida a la de conflicto, que los responsables con síntomas de mínimos a leves. Los resultados enfatizan la importancia de considerar el contenido de la tarea en la investigación observacional de familias para aumentar nuestra comprensión de las habilidades de los responsables de los niños, con o sin depresión, con el fin de modular de una manera apropiada su comportamiento y afecto en diferentes interacciones familiares. Las medidas para mejorar el control del asma en niños que padecen asma crónica y provienen de familias de bajos ingresos están en debate, incluida la utilidad de intervenciones multidisciplinarias que combinen formación sobre el asma con terapia familiar. [source] Modulation of human humoral immune response through orally administered bovine colostrumFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2001Fang He Abstract Eighteen healthy volunteers were randomized into two treatment groups and consumed liquid prepackaged bovine colostrum whey and placebo for 7 days. On days 1, 3 and 5, an attenuated Salmonella typhi Ty21a oral vaccine was given to all subjects to mimic an enteropathogenic infection. The circulating antibody secreting cells and the expression of phagocytosis receptors of the subjects before and after oral immunization were measured with the ELISPOT assay and flow cytometry. All subjects responded well to the vaccine. No significant differences were observed in ELISPOT values for IgA, IgG, IgM, Fc, and CR receptor expression on neutrophils and monocytes between the two groups. There was a trend towards greater increase in specific IgA among the subjects receiving their vaccine with bovine colostrum. These results suggest that bovine colostrum may possess some potential to enhance human special immune responses. [source] Allometric scaling of maximum metabolic rate: the influence of temperatureFUNCTIONAL ECOLOGY, Issue 4 2008C. R. White Summary 1Maximum aerobic metabolic rate, measured in terms of rate of oxygen consumption during exercise (), is well known to scale to body mass (M) with an exponent greater than the value of 0·75 predicted by models based on the geometry of systems that supply nutrients. 2Recently, the observed scaling for (,M0·872) has been hypothesized to arise because of the temperature dependence of biological processes, and because large species show a greater increase in muscle temperature when exercising than do small species. 3Based on this hypothesis, we predicted that will be positively related to ambient temperature, because heat loss is restricted at high temperatures and body temperature is likely to be elevated to a greater extent than during exercise in the cold. 4This prediction was tested using a comparative phylogenetic generalized least-squares (PGLS) approach, and 34 measurements of six species of rodent (20·5,939 g) maximally exercising at temperatures from ,16 to 30 °C. 5 is unrelated to testing temperature, but is negatively related to acclimation temperature. We conclude that prolonged cold exposure increases exercise-induced by acting as a form of aerobic training in mammals, and that elevated muscle temperatures of large species do not explain the scaling of across taxa. [source] Evidences of the gender-related differences in cardiac repolarization and the underlying mechanisms in different animal species and humanFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 1 2006Jianhua Cheng Abstract Clinical and experimental studies have shown that gender differences exist in cardiac repolarization in various animal species and human, as is evidenced by significantly longer QT, JT intervals and action potential duration in females than in males due to a reduced repolarization reserve in females. The latter is shown by the relatively greater increase in ventricular repolarization and higher incidence of torsades de pointes (TdP) in preparations from females by drugs blocking repolarizing K+ currents. These results can be modulated by gonadectomy, suggesting that gonadal steroids are important determinants of gender difference in repolarization. In human subjects, QT and JT intervals are longer in women, whereas QT dispersion and Tp-e interval (the interval from the peak to the end of T wave) are longer in men. At slow heart rates greater prolongation in QT and increase in transmural repolarization heterogeneity (i.e. increase in Tp-e) may predispose to TdP tachycardias in women. In healthy postmenopausal women, hormone replacement therapy with estrogen alone usually produced a prolongation of QT interval, while estrogen plus progesterone had no significant effects on QT interval but reduced QT dispersion. Along with these, there are still conflicting data reported. Further work is needed before the elucidation of the basis of gender differences in ventricular repolarization. [source] Effects of ouabain on contractions induced by manganese ions in Ca2+ -free, isotonic solutions with varying concentrations of K+ in guinea-pig taenia coliFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 3 2005Tetsuyuki Nasu Abstract The action of ouabain, a cell membrane Na+, K+ -ATPase blocker, on contractions induced by manganese ions (Mn2+) in Ca2+ -free, isotonic solutions with varying concentrations of K+ in the external medium were investigated in order to evaluate the underlying role of external Na+ in Mn2+ -induced contractions in isolated taenia coli of the guinea-pig. Mn2+ at 5 mm induced greater contractions as external isotonic K+ concentrations progressively increased from 10 to 100 mm. Ouabain (2 × 10,4 m) completely inhibited tension development stimulated by 5 mm Mn2+ in isotonic, 30 mm K+ (96 mm Na+) medium. Whereas, the tension inhibitory effects of ouabain became progressively weaker as isotonic, external K+ concentrations increased to 60 mm, which successively decreased external Na+ concentrations. Eventually, ouabain failed to affect contractions stimulated by Mn2+ in isotonic, 126 mm K+, Na+ -deficient medium. Ouabain caused progressively greater increase in cellular Na+ concentrations as the Na+ concentrations increased in the isotonic, K+ medium. While, pyruvate, which penetrates cell independently of external Na+, reversed the inhibition of tension by ouabain in isotonic, 30 mm K+, Na+ -sufficient (96 mm) medium containing 5 mm Mn2+. These results suggested that Mn2+ induced the contraction, which was maintained by glucose transport depending on external Na+, in the case of Na+ -sufficient medium in K+ -depolarized taenia coli. However, it induced the contraction independent of external Na+, in the case of Na+ -deficient, K+ medium. Ouabain might exhibit greater inhibition of the contraction induced by Mn2+ as the decrease in the Na+ gradient across the cell membranes continues. [source] Molecular response to climate change: temperature dependence of UV-induced DNA damage and repair in the freshwater crustacean Daphnia pulicariaGLOBAL CHANGE BIOLOGY, Issue 4 2004Emily J. MacFadyen Abstract In temperate lakes, asynchronous cycles in surface water temperatures and incident ultraviolet (UV) radiation expose aquatic organisms to damaging UV radiation at different temperatures. The enzyme systems that repair UV-induced DNA damage are temperature dependent, and thus potentially less effective at repairing DNA damage at lower temperatures. This hypothesis was tested by examining the levels of UV-induced DNA damage in the freshwater crustacean Daphnia pulicaria in the presence and absence of longer-wavelength photoreactivating radiation (PRR) that induces photoenzymatic repair (PER) of DNA damage. By exposing both live and dead (freeze-killed) Daphnia as well as raw DNA to UV-B in the presence and absence of PRR, we were able to estimate the relative importance and temperature dependence of PER (light repair), nucleotide excision repair (NER, dark repair), and photoprotection (PP). Total DNA damage increased with increasing temperature. However, the even greater increase in DNA repair rates at higher temperatures led net DNA damage (total DNA damage minus repair) to be greater at lower temperatures. Photoprotection accounted for a much greater proportion of the reduction in DNA damage than did repair. Experiments that looked at survival rates following UV exposure demonstrated that PER increased survival rates. The important implication is that aquatic organisms that depend heavily on DNA repair processes may be less able to survive high UV exposure in low temperature environments. Photoprotection may be more effective under the low temperature, high UV conditions such as are found in early spring or at high elevations. [source] Effect of packing density of hollow fibers on solute removal performances of dialyzersHEMODIALYSIS INTERNATIONAL, Issue 2009Akihiro C. YAMASHITA Abstract Solute removal performances of dialyzers are dependent not only on the solute permeabilities of the membrane but also on the module design. We have investigated how the packing density of hollow fiber (PDF) affects the solute removal performances. A series of 4 polyester polymer alloy membrane test dialyzers were assembled with varying PDFs of 29.6%, 35.3%, 44.1%, and 53.1%. Clearances (CL) were measured in vitro for creatinine (MW113), vitamin B12 (MW1355), and chymotrypsin (MW25300) with various QB=100 to 400 and QD=350 to 650 mL/min in the absence of net ultrafiltration. When QB was ,300 mL/min, no significant changes were found in creatinine CL with the increase of PDF up to 35.3%. A slightly greater increase was found in CL when QB=400 mL/min. Clearances for vitamin B12, however, increased with the increase of PDF in the range of 29.6% to 35.3%. The effects of PDF on CL were greater with larger QB. More importantly, an abrupt increase of CL was found when PDF was increased from 44.1% to 53.1%. According to a rigorous mathematical model, this may be caused by the internal filtration, which is reverse ultrafiltration occurring in a dialyzer at any given time. No significant increase was found in chymotrypsin CL when the PDF was ,35.3%, which suggested that CL for large molecules was strongly dependent on the solute permeability rather than the conditions of flow patterns. A very steep increase was also found in CL for chymotrypsin when the PDF was >44.1%, which was also considered to be due to the internal filtration. Packing density of hollow fiber can be optimized in terms of solute removal performances when the target solute and therapeutic conditions are specified. [source] Cool dialysate reduces asymptomatic intradialytic hypotension and increases baroreflex variabilityHEMODIALYSIS INTERNATIONAL, Issue 2 2009Lindsay J. CHESTERTON Abstract Intradialytic hypotension (IDH) remains an important cause of morbidity and mortality in chronic hemodialysis (HD) patients and can be ameliorated by cool temperature HD. The baroreflex arc is under autonomic control and is essential in the short-term regulation of blood pressure (BP). This study aimed to investigate if the baroreflex sensitivity (BRS) response to HD differed between standard and cool-temperature dialysate. Ten patients (mean age 67±2 years) prone to IDH were recruited into a randomized, crossover study to compare BRS variation at dialysate temperatures of 37 °C (HD37) and 35 °C (HD35). Each patient underwent continuous beat-to-beat BP monitoring during a dialysis session of HD37 and HD35. During HD37 2 patients developed symptomatic IDH, as opposed to 1 with HD35. However, asymptomatic IDH occurred with a frequency of 0.4 episodes per session with HD35 and 6.2 episodes per session during HD37 (odds ratio15.5; 95%CI 5.6,14.2). Although absolute BRS measurements did not differ between the 2 modalities, BRS variability increased during HD35. Our study has demonstrated that in IDH-prone patients, cool HD resulted in a reduction in heart rate and a greater reduction in cardiac output and stroke volume. Mean arterial pressure was maintained through a significantly greater increase in total peripheral resistance. Furthermore, although absolute BRS values during HD were not significantly altered by a reduction in dialysate temperature, there was a greater percentage increase in BRS values during cool HD. Understanding the varied causes of, and categorizing impaired hemodynamic responses to HD will enable further individualization of HD prescriptions according to patient need. [source] Radiation-induced HIF-1, cell survival pathway is inhibited by soy isoflavones in prostate cancer cellsINTERNATIONAL JOURNAL OF CANCER, Issue 7 2009Vinita Singh-Gupta Abstract We previously showed that treatment of prostate cancer cells with soy isoflavones and radiation resulted in greater cell killing in vitro, and caused downregulation of NF-,B and APE1/Ref-1. APE1/Ref-1 functions as a redox activator of transcription factors, including NF-,B and HIF-1,. These molecules are upregulated by radiation and implicated in radioresistance of cancer cells. We extended our studies to investigate the role of HIF-1, survival pathway and its upstream Src and STAT3 molecules in isoflavones and radiation interaction. Radiation induced phosphorylation of Src and STAT3 leading to induction of HIF-1,. Genistein, daidzein or a mixture of soy isoflavones did not activate this pathway. These data were observed both in PC-3 (AR-) and C4-2B (AR+) androgen-independent cell lines. Pretreatment with isoflavones inhibited Src/STAT3/HIF-1, activation by radiation and nuclear translocation of HIF-1,. These findings correlated with decreased expression of APE1/Ref-1 and DNA binding activity of HIF-1, and NF-,B. In APE1/Ref-1 cDNA transfected cells, radiation caused a greater increase in HIF-1, and NF-,B activities but this effect was inhibited by pretreatment with soy prior to radiation. Transfection experiments indicate that APE1/Ref-1 inhibition by isoflavones impairs the radiation-induced transcription activity of NF-,B and HIF-1,. This mechanism could result in the inhibition of genes essential for tumor growth and angiogenesis, as demonstrated by inhibition of VEGF production and HUVECs tube formation. Our novel findings suggest that the increased responsiveness to radiation mediated by soy isoflavones could be due to pleiotropic effects of isoflavones blocking cell survival pathways induced by radiation including Src/STAT3/HIF-1,, APE1/Ref-1 and NF-,B. © 2008 Wiley-Liss, Inc. [source] Nox1 is over-expressed in human colon cancers and correlates with activating mutations in K-RasINTERNATIONAL JOURNAL OF CANCER, Issue 1 2008Eunice Laurent Abstract The NADPH-oxidase 1 (Nox1) is a homolog of gp91phox, the catalytic subunit of the phagocyte superoxide-generating NADPH-oxidase. Nox1 is expressed in normal colon epithelial cells and in colon tumor cell lines, and overexpression in model cells has been implicated in stimulation of mitogenesis and angiogenesis and inhibition of apoptosis. This suggests that aberrant expression of Nox1 could contribute to the development of colorectal cancer. Herein, we examine the expression of Nox1 mRNA in 24 colon tumors of various stages compared with paired adjacent normal tissue from the same patient, and correlate expression with some common mutations associated with colon cancer. Nox1 was overexpressed compared with paired normal tissue in 57% of tumors as early as the adenoma stage, with no correlation of expression level with tumor stage. Overexpression of Nox1 mRNA correlated with Nox1 protein levels assessed by immunofluorescence and immunohistochemistry with an antibody specific for Nox1. There was a strong correlation between Nox1 mRNA level and activating mutations in codons 12 and 13 of K-Ras. Eighty percent (8/10) of tumors with codons 12 and 13 mutations had a 2-fold or more increase in Nox1 mRNA, and 70% (7/10) had a 5-fold or greater increase. Transgenic mice expressing K-RasG12V in the intestinal epithelium also expressed markedly elevated Nox1 in both small and large intestine. There was no correlation between inactivating mutations in the tumor suppressor p53 and Nox1 expression. We conclude that Nox1 mRNA and protein are overexpressed in colon cancer and are strongly correlated with activating mutations in K-Ras. © 2008 Wiley-Liss, Inc. [source] Surface air temperature trends in Southern Brazil for 1960,2002INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 7 2008Jose A. Marengo Abstract Trends in minimum and maximum air temperature and in the diurnal thermal range (DTR), and derived indices of extreme temperatures since the 1960's are assessed for southern Brazil. Most meteorological stations show steep increases in the night-time temperatures (depicted by the minimum temperature) as compared to slight increases in the daytime temperature (depicted by the maximum temperature), both year round and at the seasonal level. The warming trends are stronger during winter as compared to summer. Consequently, the observed annual and seasonal negative DTR trends in southern Brazil during the last 40 years are largely due to the greater increase in nighttime temperatures rather than daytime temperatures. At decadal timescales, the presence of more intense and frequent El Niño events during the last 20 years also contributes to warming and explains the steep increase in the air temperature extremes trends during this period, as compared to the relatively colder 1960,1980 period, especially for winter. Indices of temperature extremes defined using fixed limits for maximum and minimum temperatures for colder or warmer days were compared with percentile-based indices defined in the recent literature. The comparison shows that the frequency of warmer days increased during both summer and winter, especially during the last two decades. The observed positive tendencies in minimum temperatures and warmer days during winter occur even though extreme cold events and freezing conditions occurred in 1975, 1994 and 2000. Copyright © 2007 Royal Meteorological Society [source] Immigration Policy and Employment Conditions of US Immigrants from Mexico, Nicaragua, and the Dominican Republic1INTERNATIONAL MIGRATION, Issue 5 2005Katharine M. Donato ABSTRACT Prior studies suggest that the passage of the Immigration Reform and Control Act (IRCA) in 1986 signalled a deterioration in the labour market conditions of Mexican migrants. In this paper, we examine whether and how labour market conditions worsened for Dominicans and Nicaraguans after 1986, and the extent to which these shifts were comparable to those experienced by Mexicans. Our analysis relies on a new source of data that offers comparable data across the three national origins. We estimate multivariate models that capture the effects of demographic attributes, human and social capital, migration-specific human and social capital, legal status, period of trip, national origin, and other controls on the hourly wages earned by household heads and whether they received cash wages on their last US trip. Models with interaction terms reveal significant pre- and post-1986 wage effects, but few differences in these effects between Mexicans and Dominicans or Nicaraguans. In contrast, group differences appear in the risk of cash receipt of wages. Dominicans and Nicaraguans experienced a greater increase in this risk relative to Mexicans pre- and post-1986. Together, these findings depict a broader, negative impact of IRCA on Latino migrant wages than has been documented elsewhere. [source] Uncertainty, Real Options, and Cost Behavior: Evidence from Washington State HospitalsJOURNAL OF ACCOUNTING RESEARCH, Issue 5 2005SANJAY KALLAPUR ABSTRACT This study tests an implication of the real-options theory of investment, that uncertainty leads firms to prefer technologies with low fixed and high variable costs. In 1983, a change in Medicare reimbursement increased the uncertainty of revenues for hospitals. Using a sample of 831 departments in 59 Washington State hospitals over the 1977,1994 period, we find that the ratio of variable to total costs increased after 1983. This increase is not attributable to a gradual increase in the ratio over time: We estimate a significant increase after 1983 even after controlling for a time trend. Further, we find a greater increase in the variable-to-total cost ratio for hospitals that had higher percentages of Medicare patients, increasing our confidence in the conclusion that the change in cost behavior is attributable to Medicare's change in reimbursement. [source] Heat Shock Protein in Developing Grains in Relation to Thermotolerance for Grain Growth in WheatJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2010P. Sharma-Natu Abstract Wheat (Triticum aestivum L.) cvs DL 153-2 and HD 2285 (relatively tolerant), HD 2329 and WH 542 (relatively susceptible), were grown under normal (27 November) and late (28 December) sown conditions. In another experiment, these cultivars were grown under normal sowing and at anthesis stage, they were transferred to control (C) and heated (H) open top chambers (OTCs). Under late sowing, wheat cultivars were exposed to a mean maximum temperature of up to 3.6 °C higher than normal sowing and in H-OTCs, mean maximum temperature was 3.2 °C higher than C-OTCs during grain growth period. Heat susceptibility index (S) for grain growth and grain yield was determined at maturity in both the experiments. The level of heat shock protein (HSP 18) in the developing grains was determined in C- and H-OTC grown plants and in normal and late sown plants by Western blot analysis. The moderately high temperature exposure increased the accumulation of HSP 18 in the developing grains. The relatively tolerant cultivars, as also revealed from S, showed a greater increase in HSP 18 compared with susceptible types in response to moderate heat stress. An association of HSP 18 with thermotolerance for grain growth in wheat was indicated. [source] An Evaluation of the Implementation of Hand Held Health Records with Adults with Learning Disabilities: A Cluster Randomized Controlled TrialJOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES, Issue 2 2010Vicky Turk Background, Personal health records were implemented with adults with learning disabilities (AWLD) to try to improve their health-care. Materials and Method, Forty GP practices were randomized to the Personal Health Profile (PHP) implementation or control group. Two hundred and one AWLD were interviewed at baseline and 163 followed up after 12 months intervention (PHP group). AWLD and carers of AWLD were employed as research interviewers. AWLD were full research participants. Results, Annual consultation rates in the intervention and control groups at baseline were low (2.3 and 2.6 visits respectively). A slightly greater increase occurred over the year in the intervention group 0.6 (,0.4 to 1.6) visits/year compared with controls. AWLD in PHP group reported more health problems at follow-up 0.9 (0.0 to 1.8). AWLD liked their PHP (92%) but only 63% AWLD and 55% carers reported PHP usage. Carers had high turnover (34%). Conclusions, No significant outcomes were achieved by the intervention. [source] Enhanced Chondrogenesis and Wnt Signaling in PTH-Treated Fractures,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 12 2007Sanjeev Kakar Abstract Studies have shown that systemic PTH treatment enhanced the rate of bone repair in rodent models. However, the mechanisms through which PTH affects bone repair have not been elucidated. In these studies we show that PTH primarily enhanced the earliest stages of endochondral bone repair by increasing chondrocyte recruitment and rate of differentiation. In coordination with these cellular events, we observed an increased level of canonical Wnt-signaling in PTH-treated bones at multiple time-points across the time-course of fracture repair, supporting the conclusion that PTH responses are at least in part mediated through Wnt signaling. Introduction: Since FDA approval of PTH [PTH(1,34); Forteo] as a treatment for osteoporosis, there has been interest in its use in other musculoskeletal conditions. Fracture repair is one area in which PTH may have a significant clinical impact. Multiple animal studies have shown that systemic PTH treatment of healing fractures increased both callus volume and return of mechanical competence in models of fracture healing. Whereas the potential for PTH has been established, the mechanism(s) by which PTH produces these effects remain elusive. Materials and Methods: Closed femoral fractures were generated in 8-wk-old male C57Bl/6 mice followed by daily systemic injections of either saline (control) or 30 ,g/kg PTH(1,34) for 14 days after fracture. Bones were harvested at days 2, 3, 5, 7, 10, 14, 21, and 28 after fracture and analyzed at the tissue level by radiography and histomorphometry and at the molecular and biochemical levels level by RNase protection assay (RPA), real-time PCR, and Western blot analysis. Results: Quantitative ,CT analysis showed that PTH treatment induced a larger callus cross-sectional area, length, and total volume compared with controls. Molecular analysis of the expression of extracellular matrix genes associated with chondrogenesis and osteogenesis showed that PTH treated fractures displayed a 3-fold greater increase in chondrogenesis relative to osteogenesis over the course of the repair process. In addition, chondrocyte hypertrophy occurred earlier in the PTH-treated callus tissues. Analysis of the expression of potential mediators of PTH actions showed that PTH treatment significantly induced the expression of Wnts 4, 5a, 5b, and 10b and increased levels of unphosphorylated, nuclear localized ,-catenin protein, a central feature of canonical Wnt signaling. Conclusions: These results showed that the PTH-mediated enhancement of fracture repair is primarily associated with an amplification of chondrocyte recruitment and maturation in the early fracture callus. Associated with these cellular effects, we observed an increase in canonical Wnt signaling supporting the conclusion that PTH effects on bone repair are mediated at least in part through the activation of Wnt-signaling pathways. [source] Is a School-Based Physical Activity Intervention Effective for Increasing Tibial Bone Strength in Boys and Girls?,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 3 2007Heather M Macdonald Abstract This 16-month randomized, controlled school-based study compared change in tibial bone strength between 281 boys and girls participating in a daily program of physical activity (Action Schools! BC) and 129 same-sex controls. The simple, pragmatic intervention increased distal tibia bone strength in prepubertal boys; it had no effect in early pubertal boys or pre or early pubertal girls. Introduction: Numerous school-based exercise interventions have proven effective for enhancing BMC, but none have used pQCT to evaluate the effects of increased loading on bone strength during growth. Thus, our aim was to determine whether a daily program of physical activity, Action Schools! BC (AS! BC) would improve tibial bone strength in boys and girls who were pre- (Tanner stage 1) or early pubertal (Tanner stage 2 or 3) at baseline. Materials and Methods: Ten schools were randomized to intervention (INT, 7 schools) or control (CON, 3 schools). The bone-loading component of AS! BC included a daily jumping program (Bounce at the Bell) plus 15 minutes/day of classroom physical activity in addition to regular physical education. We used pQCT to compare 16-month change in bone strength index (BSI, mg2/mm4) at the distal tibia (8% site) and polar strength strain index (SSIp, mm3) at the tibial midshaft (50% site) in 281 boys and girls participating in AS! BC and 129 same-sex controls. We used a linear mixed effects model to analyze our data. Results: Children were 10.2 ± 0.6 years at baseline. Intervention boys tended to have a greater increase in BSI (+774.6 mg2/mm4; 95% CI: 672.7, 876.4) than CON boys (+650.9 mg2/mm4; 95% CI: 496.4, 805.4), but the difference was only significant in prepubertal boys (p = 0.03 for group × maturity interaction). Intervention boys also tended to have a greater increase in SSIp (+198.6 mm3; 95% CI: 182.9, 214.3) than CON boys (+177.1 mm3; 95% CI: 153.5, 200.7). Change in BSI and SSIp was similar between CON and INT girls. Conclusions: Our findings suggest that a simple, pragmatic program of daily activity enhances bone strength at the distal tibia in prepubertal boys. The precise exercise prescription needed to elicit a similar response in more mature boys or in girls might be best addressed in a dose,response trial. [source] Decreased oxidative stress and greater bone anabolism in the aged, when compared to the young, murine skeleton with parathyroid hormone administrationAGING CELL, Issue 5 2010Robert L. Jilka Summary Because of recent insights into the pathogenesis of age-related bone loss, we investigated whether intermittent parathyroid hormone (PTH) administration antagonizes the molecular mechanisms of the adverse effects of aging on bone. Parathyroid hormone produced a greater increase in vertebral trabecular bone mineral density and bone volume as well as a greater expansion of the endocortical bone surface in the femur of 26- when compared to 6 -month-old female C57BL/6 mice. Moreover, PTH increased trabecular connectivity in vertebrae, and the toughness of both vertebrae and femora in old, but not young, mice. Parathyroid hormone also increased the rate of bone formation and reduced osteoblast apoptosis to a greater extent in the old mice. Most strikingly, PTH reduced reactive oxygen species, p66Shc phosphorylation, and expression of the lipoxygenase Alox15, and it increased glutathione and stimulated Wnt signaling in bone of old mice. Parathyroid hormone also antagonized the effects of oxidative stress on p66Shc phosphorylation, Forkhead Box O transcriptional activity, osteoblast apoptosis, and Wnt signaling in vitro. In contrast, administration of the antioxidants N -acetyl cysteine or pegylated catalase reduced osteoblast progenitors and attenuated proliferation and Wnt signaling. These results suggest that PTH has a greater bone anabolic efficacy in old age because in addition to its other positive actions on bone formation, it antagonizes the age-associated increase in oxidative stress and its adverse effects on the birth and survival of osteoblasts. On the other hand, ordinary antioxidants cannot restore bone mass in old age because they slow remodeling and attenuate osteoblastogenesis by interfering with Wnt signaling. [source] Free Radicals in Wheat Seeds Studied by Electron Spin ResonanceJOURNAL OF FOOD SCIENCE, Issue 6 2002F. Szöcs ABSTRACT: We used electron spin resonance (ESR) to investigate free radicals in wheat seeds in air or under vacuum in relation to annealing temperature. Annealing in the 100 to 200 °C range resulted in concentration increases of free radicals in samples. A greater increase was observed for experiments carried out in air than for those under vacuum. Most free radicals occurred in the grain surface layer. The bran contained a concentration of free radicals 100 times greater than that of the white grain portion. The reaction of stable free radicals in bran was also studied during thermal decomposition of dibenzoyl peroxide at high pressure. They reacted with shortlived peroxyl radicals in bran to produce a nonradical product. [source] Role of meal carbohydrate content for the imbalance of plasma amino acids in patients with liver cirrhosisJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 8 2007Ewert Schulte-Frohlinde Abstract Background and Aim:, Imbalance of circulating branched chain amino acids (BCAA) versus aromatic amino acids (AAA) and hyperinsulinemia are common metabolic alterations in patients with liver cirrhosis. The aim of this study was to characterize the effect of the carbohydrate component of a protein-rich mixed meal on postprandial plasma concentrations of 21 amino acids, insulin and C-peptide in patients with compensated liver cirrhosis. Furthermore, the effect of a dietary intervention on the metabolic alterations in cirrhotic patients was examined. Methods:, Eighteen patients with cirrhosis and 12 healthy volunteers received a protein-rich meal (pork filet 200 g) with or without carbohydrates (bread 50 g, glucose 20 g). A subgroup of four cirrhotic patients received an isoenergetic (117 kJ/kg bw) carbohydrate-enriched (60%) and -restricted (20%) diet for 7 days each. Results:, In the cirrhotic patients, basal plasma insulin and C-peptide concentrations were significantly elevated. The ingestion of a protein-rich meal without additional carbohydrates led to a significantly greater increase of insulin and C-peptide in the cirrhotic patients compared to controls. Postprandial increases of leucine and isoleucine were reduced, whereas those of phenylalanine were higher in cirrhotic patients. The addition of carbohydrates led to higher insulin and C-peptide plasma concentrations in cirrhotic patients. Postprandial BCAA increases were more impaired in the cirrhotic group after additional carbohydrate ingestion (46%vs 82%). After the carbohydrate-restricted diet for 7 days BCAA plasma levels increased but the BCAA/AAA ratio remained unaltered. Conclusions:, The carbohydrate content of a meal enhances reduction of BCAA plasma concentrations in clinically stable cirrhotic patients. An imbalanced BCAA/AAA ratio cannot be avoided by a carbohydrate-reduced diet alone, supporting mandatory BCAA supplementation. [source] Increased phosphorylation and redistribution of NMDA receptors between synaptic lipid rafts and post-synaptic densities following transient global ischemia in the rat brainJOURNAL OF NEUROCHEMISTRY, Issue 1 2005Shintaro Besshoh Abstract Ischemia results in increased phosphorylation of NMDA receptors. To investigate the possible role of lipid rafts in this increase, lipid rafts and post-synaptic densities (PSDs) were isolated by the extraction of rat brain synaptosomes with Triton X-100 followed by sucrose density gradient centrifugation. Lipid rafts accounted for the majority of PSD-95, whereas SAP102 was predominantly located in PSDs. Between 50 and 60% of NMDA receptors were associated with lipid rafts. Greater than 85,90% of Src and Fyn were present in lipid rafts, whereas Pyk2 was mainly associated with PSDs. Lipid rafts and PSDs were isolated from animals subjected to 15 min of global ischemia followed by 6 h of recovery. Ischemia did not affect the yield, density, flotillin-1 or cholesterol content of lipid rafts. Following ischemia, the phosphorylation of NR1 by protein kinase C and tyrosine phosphorylation of NR2A and NR2B was increased in both lipid rafts and PSDs, with a greater increase in tyrosine phosphorylation occurring in the raft fraction. Following ischemia, NR1, NR2A and NR2B levels were elevated in PSDs and reduced in lipid rafts. The findings are consistent with a model involving close interaction between lipid rafts and PSDs and a role for lipid rafts in ischemia-induced signaling pathways. [source] Altered distribution of mitochondria impairs calcium homeostasis in rat hippocampal neurons in cultureJOURNAL OF NEUROCHEMISTRY, Issue 1 2003Guang Jian Wang Abstract The specificity of Ca2+ signals is conferred in part by limiting changes in cytosolic Ca2+ to subcellular domains. Mitochondria play a major role in regulating Ca2+ in neurons and may participate in its spatial localization. We examined the effects of changes in the distribution of mitochondria on NMDA-induced Ca2+ increases. Hippocampal cultures were treated with the microtubule-destabilizing agent vinblastine, which caused the mitochondria to aggregate and migrate towards one side of the neuron. This treatment did not appear to decrease the energy status of mitochondria, as indicated by a normal membrane potential and pH gradient across the inner membrane. Moreover, electron microscopy showed that vinblastine treatment altered the distribution but not the ultrastructure of mitochondria. NMDA (200 µm, 1 min) evoked a greater increase in cytosolic Ca2+ in vinblastine-treated cells than in untreated cells. This increase did not result from impaired Ca2+ efflux, enhanced Ca2+ influx, opening of the mitochondrial permeability transition pore or altered function of endoplasmic reticulum Ca2+ stores. Ca2+ uptake into mitochondria was reduced by 53% in vinblastine-treated cells, as reported by mitochondrially targeted aequorin. Thus, the distribution of mitochondria maintained by microtubules is critical for buffering Ca2+ influx. A subset of mitochondria close to a Ca2+ source may preferentially regulate Ca2+ microdomains, set the threshold for Ca2+ -induced toxicity and participate in local ATP production. [source] Relationship between non-functional masticatory activity and central dopamine in stressed ratsJOURNAL OF ORAL REHABILITATION, Issue 11 2010F. M. GÓMEZ Summary, In humans, diurnal tooth-clenching and other oral stereotyped behaviour are associated with stress/anxiety. In rodents, gnawing/biting of objects is observed during exposure to stress. Both nigrostriatal and mesocortical dopaminergic systems are involved in the development of this coping behaviour. To clarify the relationship between central dopaminergic activity and stress-induced parafunctional masticatory behaviour, using microdialysis in vivo, we assessed the changes in extracellular dopamine concentrations in both prefrontal cortex and striatum of rats subjected to a mild tail pinch. The animals were divided into two groups according to the degree of non-functional masticatory activity (NFMA) displayed during exposure to tail pinch. In prefrontal cortex, rats which displayed severe NFMA showed a greater increase in extracellular dopamine concentration in relation to basal values (Emax = 184 ± 26%) than those which did not display this coping behaviour (Emax = 139 ± 23%) (FNFMA[1,86] = 3·97; P < 0·05) (n = 17). A positive association was also found between cortical dopamine maximal value from baseline and the degree of NFMA displayed (r = 0·36; P < 0·05) (n = 17). There were no significant differences in the tail-pinch-induced striatal dopamine increase between both groups of rats (Emax = 130 ± 10%) (n = 17). These results provide further evidence in support of prefrontal dopamine playing a relevant role in the expression of stress-induced masticatory coping behaviour. [source] |