Creatine Supplementation Prevents the Accumulation of Fat in the Livers of Rats Fed a High-Fat Diet

The aim of the present study was to examine the effects of creatine supplementation on liver fat accumulation induced by a high-fat diet in rats. Rats were fed 1 of 3 different diets for 3 wk: a control liquid diet (C), a high-fat liquid diet (HF), or a high-fat liquid diet supplemented with creatine (HFC). The C and HF diets contained, respectively, 35 and 71% of energy derived from fat. Creatine supplementation involved the addition of 1% (wt:v) of creatine monohydrate to the liquid diet. The HF diet increased total liver fat concentration, liver TG, and liver TBARS and decreased the hepatic S-adenosylmethionine (SAM) concentration. Creatine supplementation normalized all of these perturbations. Creatine supplementation significantly decreased the renal activity of L-arginine:glycine amidinotransferase and plasma guanidinoacetate and prevented the decrease in hepatic SAM concentration in rats fed the HF diet. However, there was no change in either the phosphatidylcholine:phosphatidylethanolamine (PE) ratio or PE N-methyltransferase activity. The HF diet decreased mRNA for PPAR as well as 2 of its targets, carnitine palmitoyltransferase and long-chain acylCoA dehydrogenase. Creatine supplementation normalized these mRNA levels. In conclusion, creatine supplementation prevented the fatty liver induced by feeding rats a HF diet, probably by normalization of the expression of key genes of beta-oxidation. J. Nutr. 141: 1799-1804, 2011.

Effect of ion exchange on R-curve behavior of a dental porcelain

The objective of this study was to evaluate the effect of the ion exchange treatment on the R-curve behavior of a leucite-reinforced dental porcelain, testing the hypothesis that the ion exchange is able to improve the R-curve behavior of the porcelain studied. Porcelain disks were sintered, finely polished, and submitted to an ion exchange treatment with a KNO(3) paste. The R-curve behavior was assessed by fracturing the specimens in a biaxial flexure design after making Vickers indentations in the center of the polished surface with loads of 1.8, 3.1, 4.9, 9.8, 31.4, and 49.0 N. The results showed that the ion exchange process resulted in significant improvements in terms of fracture toughness and flexural strength as compared to the untreated material. Nevertheless, the rising R-curve behavior previously observed in the control group disappeared after the ion exchange treatment, i.e., fracture toughness did not increase with the increase in crack size for the treated group.

Fatigue and damage accumulation of veneer porcelain pressed on Y-TZP

Objectives: This study compared the reliability and fracture patterns of zirconia cores veneered with pressable porcelain submitted to either axial or off-axis sliding contact fatigue. Methods: Forty-two Y-TZP plates (12 mm x 12 mm x 0.5 mm) veneered with pressable porcelain (12 mm x 12 mm x 1.2 mm) and adhesively luted to water aged composite resin blocks (12 mm x 12 mm x 4 mm) were stored in water at least 7 days prior to testing. Profiles for step-stress fatigue (ratio 3:2:1) were determined from single load to fracture tests (n = 3). Fatigue loading was delivered on specimen either on axial (n = 18) or off-axis 30 degrees angulation (n = 18) to simulate posterior tooth cusp inclination creating a 0.7 mm slide. Single load and fatigue tests utilized a 6.25 mm diameter WC indenter. Specimens were inspected by means of polarized-light microscope and SEM. Use level probability Weibull curves were plotted with 2-sided 90% confidence bounds (CB) and reliability for missions of 50,000 cycles at 200 N (90% CB) were calculated. Results: The calculated Weibull Beta was 3.34 and 2.47 for axial and off-axis groups, respectively, indicating that fatigue accelerated failure in both loading modes. The reliability data for a mission of 50,000 cycles at 200 N load with 90% CB indicates no difference between loading groups. Deep penetrating cone cracks reaching the core-veneer interface were observed in both groups. Partial cones due to the sliding component were observed along with the cone cracking for the off-axis group. No Y-TZP core fractures were observed. Conclusions: Reliability was not significantly different between axial and off-axis mouth-motion fatigued pressed over Y-TZP cores, but incorporation of sliding resulted in more aggressive damage on the veneer. (C) 2009 Elsevier Ltd. All rights reserved.

Accumulation of manganese in Neisseria gonorrhoeae correlates with resistance to oxidative killing by superoxide anion and is independent of superoxide dismutase activity

As a facultative aerobe with a high iron requirement and a highly active aerobic respiratory chain, Neisseria gonorrhoeae requires defence systems to respond to toxic oxygen species such as superoxide. It has been shown that supplementation of media with 100 muM Mn(II) considerably enhanced the resistance of this bacterium to oxidative killing by superoxide. This protection was not associated with the superoxide dismutase enzymes of N. gonorrhoeae. In contrast to previous studies, which suggested that some strains of N. gonorrhoeae might not contain a superoxide dismutase, we identified a sodB gene by genome analysis and confirmed its presence in all strains examined by Southern blotting, but found no evidence for sodA or sodC. A sodB mutant showed very similar susceptibility to superoxide killing to that of wild-type cells, indicating that the Fe-dependent SOD B did not have a major role in resistance to oxidative killing under the conditions tested. The absence of a sodA gene indicated that the Mn-dependent protection against oxidative killing was independent of Mn-dependent SOD A. As a sodB mutant also showed Mn-dependent resistance to oxidative killing, then it is concluded that this resistance is independent of superoxide dismutase enzymes. Resistance to oxidative killing was correlated with accumulation of Mn(II) by the bacterium. We hypothesize that this bacterium uses Mn(II) as a chemical quenching agent in a similar way to the already established process in Lactobacillus plantarum. A search for putative Mn(II) uptake systems identified an ABC cassette-type system (MntABC) with a periplasmic-binding protein (MntC). An mntC mutant was shown to have lowered accumulation of Mn(II) and was also highly susceptible to oxidative killing, even in the presence of added Mn(II). Taken together, these data show that N. gonorrhoeae possesses a Mn(II) uptake system that is critical for resistance to oxidative stress.

Effects of high-dose etidronate treatment on microdamage accumulation and biomechanical properties in beagle bone before occurrence of spontaneous fractures

We recently demonstrated that suppressed bone remodeling allows microdamage to accumulate and causes reductions in some mechanical properties. However, in our previous study, I year treatment with high-dose etidronate (EHDP) did not increase microdamage accumulation in most skeletal sites of dogs in spite of complete remodeling suppression and the occurrence of spontaneous fractures of ribs and/or thoracic spinous processes. This study evaluates the effects of EHDP on microdamage accumulation and biomechanical properties before fractures occur. Thirty-six female beagles, 1-2 years old, were treated daily for 7 months with subcutaneous injections of saline vehicle (CNT) or EHDP at 0.5 (E-low) or 5 mg/kg per day (E-high). After killing, bone mineral measurement, histomorphometry, microdamage analysis, and biomechanical testing were performed. EHDP treatment suppressed intracortical and trabecular remodeling by 60%-75% at the lower dose, and by 100% at the higher dose. Osteoid accumulation caused by a mineralization deficit occurred only in the E-high group, and this led to a reduction of mineralized bone mass. Microdamage accumulation increased significantly by two- to fivefold in the rib, lumbar vertebra, ilium, and thoracic spinous process in E-low, and by twofold in the lumbar vertebra and ilium in E-high. However, no significant increase in damage accumulation was observed in ribs or thoracic spinous processes in E-high where fractures occur following 12 months of treatment. Mechanical properties of lumbar vertebrae and thoracic spinous processes were reduced significantly in both E-low and E-high. These findings suggest that suppression of bone remodeling by EHDP allows microdamage accumulation, but that osteoid accumulation reduces production of microdamage. (Bone 29:271-278; 2001) (C) 2001 by Elsevier Science Inc. All rights reserved.

Effects of suppressed bone turnover by bisphosphonates on microdamage accumulation and biomechanical properties in clinically relevant skeletal sites in beagles

We recently demonstrated that suppression of bone remodeling allows microdamage to accumulate, leading to reduced bone toughness in the rib cortex of dogs. This study evaluates the effects of reduced bone turnover produced by bisphosphonates on microdamage accumulation and biomechanical properties at clinically relevant skeletal sites in the same dogs. Thirty-six female beagles, 1-2 years old, were divided into three groups. The control group was treated daily for 12 months with saline vehicle (CNT), The remaining two groups were treated daily with risedronate at a dose of 0.5 mg/kg per day (RIS), or alendronate at 1.0 mg/kg per day (ALN) orally, The doses of these bisphosphonates were six times the clinical doses approved for treatment of osteoporosis in humans. After killing, the L-1 vertebra was scanned by dual-energy X-ray absorptiometry (DXA), and the L-2 vertebra and right ilium were assigned to histomorphometry, The L-3 vertebra, left ilium, Th-2 spinous process, and right femoral neck were used for microdamage analysis. The L-4 vertebra and Th-1 spinous process were mechanically tested to failure in compression and shear, respectively. One year treatment with risedronate or alendronate significantly suppressed trabecular remodeling in vertebrae (RIS 90%, ALN 95%) and ilium (RIS 76%, ALN 90%) without impairment of mineralization, and significantly increased microdamage accumulation in all skeletal sites measured. Trabecular bone volume and vertebral strength increased significantly following 12 month treatment. However, normalized toughness of the L-4 vertebra was reduced by 21% in both RIS (p = 0.06) and ALN (p = 0.05) groups. When the two bisphosphonate groups were pooled in a post hoc fashion for analysis, this reduction in toughness reached statistical significance (p = 0.02), This study demonstrates that suppression of trabecular bone turnover by high doses of bisphosphonates is associated with increased vertebral strength, even though there is significant microdamage accumulation and a reduction in the intrinsic energy absorption capacity of trabecular bone. (C) 2001 by Elsevier Science Inc. All rights reserved.

Accumulation of human heat shock protein 60-reactive T cells in the gingival tissues of periodontitis patients

Heat shock protein 60s (hsp60) are remarkably immunogenic, and both T-cell and antibody responses to hsp60 have been reported in various inflammatory conditions. To clarify the role of hsp60 in T-cell responses in periodontitis, we examined the proliferative response of peripheral blood mononuclear cells (PBMC), as well as the cytokine profile and T-cell clonality, for periodontitis patients and controls following stimulation with recombinant human hsp60 and Porphyromonas gingivalis GroEL. To confirm the infiltration of hsp60-reactive T-cell clones into periodontitis lesions, nucleotide sequences within complementarity-determining region 3 of the T-cell receptor (TCR) beta-chain were compared between hsp60-reactive peripheral blood T cells and periodontitis lesion-infiltrating T cells. Periodontitis patients demonstrated significantly higher proliferative responses of PBMC to human hsp60, but not to P. gingivalis GroEL, than control subjects. The response was inhibited by anti-major histocompatibility complex class 11 antibodies. Analysis of the nucleotide sequences of the TCR demonstrated that human hsp60-reactive T-cell clones and periodontitis lesion-infiltrating T cells have the same receptors, suggesting that hsp60-reactive T cells accumulate in periodontitis lesions. Analysis of the cytokine profile demonstrated that hsp60-reactive PBMC produced significant levels of gamma interferon (IFN-gamma) in periodontitis patients, whereas P. gingivalis GroEL did not induce any, skewing toward a type1 or type2 cytokine profile. In control subjects no significant expression of IFN-gamma or interleukin 4 was induced. These results suggest that periodontitis patients have human hsp60-reactive T cells with a type I cytokine profile in their peripheral blood T-cell pools.

Nitrification in a Vertisol subsoil and its relationship to the accumulation of ammonium-nitrogen at depth

Unusually high concentrations of ammonium have been observed in a Vertisol below 1 m depth in southeast Queensland. This study investigated the possibility that an absence of nitrification is allowing this ammonium to accumulate and persist over time, and examined the soil environmental characteristics that may be responsible for limiting nitrifying organisms. The possibility that anaerobiosis, soil acidity, soil salinity, low organic carbon concentrations, and/or an absence of active nitrifying microorganisms were responsible for limiting nitrification was examined in laboratory and field studies. The presence/absence of anaerobic conditions was determined qualitatively using a field test to give an indication of electron lability. In addition, an incubation study was conducted and soil environmental conditions were improved for nitrifying organisms by adjusting the pH from 4.4 to 7, adjusting the electrical conductivity from 1.6 to 0.5 dS/m, amending with a soluble carbon substrate at a rate of 500 mg/kg, and using microorganisms from the surface horizon to inoculate to the subsoil. Over a 180-day period no nitrification was detected in the control samples from the incubation study, indicating that an extremely low rate of nitrification is likely to be responsible for allowing ammonium to accumulate in this soil. Analysis of the effect of soil environmental conditions on nitrification revealed that anaerobic conditions did not exist at depth and that pH, EC, organic carbon, and inoculation treatments added in isolation had no effect on nitrification. However, when inoculum was added to the soil in combination with pH, a significant increase in nitrification was observed, and the greatest amount of nitrification was observed when inoculum, pH, and EC treatments were added in combination. It was concluded that the reason for the low rate of nitrification in this soil is primarily the absence of a significant population of active nitrifying microorganisms, which may have been unable to colonise the subsoil environment due to its acidic, and to a lesser extent, its saline environment.

Simulating growth, development, and yield of tillering pearl millet. III. Biomass accumulation and partitioning

Pearl millet landraces from Rajasthan, India, yield significantly less than improved cultivars under optimum growing conditions, but not under stressed conditions. To successfully develop a simulation model for pearl millet, capable of capturing such genotype x environment (G x E) interactions for grain yield, we need to understand the causes of the observed yield interaction. The aim of this paper is to quantify the key parameters that determine the accumulation and partitioning of biomass: the,light extinction coefficient, radiation use efficiency (RUE), pattern of dry matter allocation to the leaf blades, the determination of grain number, and the rate and duration of dry matter accumulation into individual grains. We used data on improved cultivars and landraces, obtained from both published and unpublished sources collected at ICRISAT, Patancheru, India. Where possible, the effects of cultivar and axis (main shoot vs. tillers) on these parameters were analysed, as previous research suggested that G x E interactions for grain yield are associated with differences in tillering habit. Our results indicated there were no cultivar differences in extinction coefficient, RUE, and biomass partitioning before anthesis, and differences between axes in biomass partitioning were negligible. This indicates there was no basis for cultivar differences in the potential grain yield. Landraces, however, produced consistently less grain yield for a given rate of dry matter accumulation at anthesis than did improved cultivars. This was caused by a combination of low grain number and small grain size. The latter was predominantly due to a lower grain growth rate, as genotypic differences in the duration of grain filling were relatively small. Main shoot and tillers also had a similar duration of grain filling. The low grain yield of the landraces was associated with profuse nodal tillering, supporting the hypothesis that grain yield was below the potential yield that could be supported by assimilate availability. We hypothesise this is a survival strategy, which enhances the prospects to escape the effects of stress around anthesis. (C) 2002 E.J. van Oosterom. Published by Elsevier Science B.V. All rights reserved.

Predicting plant leaf area production: shoot assimilate accumulation and partitioning, and leaf area ratio, are stable for a wide range of sorghum population densities

Predicting plant leaf area production is required for modelling carbon balance and tiller dynamics in plant canopies. Plant leaf area production can be studied using a framework based on radiation intercepted, radiation use efficiency (RUE) and leaf area ratio (LAR) (ratio of leaf area to net above-ground biomass). The objective of this study was to test this framework for predicting leaf area production of sorghum during vegetative development by examining the stability of the contributing components over a large range of plant density. Four densities, varying from 2 to 16 plants m(-2), were implemented in a field experiment. Plants were either allowed to tiller or were maintained as uniculm by systematic tiller removal. In all cases, intercepted radiation was recorded daily and leaf area and shoot dry matter partitioning were quantified weekly at individual culm level. Up to anthesis, a unique relationship applied between fraction of intercepted radiation and leaf area index, and between shoot dry weight accumulation and amount of intercepted radiation, regardless of plant density. Partitioning of shoot assimilate between leaf, stem and head was also common across treatments up to anthesis, at both plant and culm levels. The relationship with thermal time (TT) from emergence of specific leaf area (SLA) and LAR of tillering plants did not change with plant density. In contrast, SLA of uniculm plants was appreciably lower under low-density conditions at any given TT from emergence. This was interpreted as a consequence of assimilate surplus arising from the inability of the plant to compensate by increasing the leaf area a culm could produce. It is argued that the stability of the extinction coefficient, RUE and plant LAR of tillering plants observed in these conditions provides a reliable way to predict leaf area production regardless of plant density. Crown Copyright (C) 2002 Published by Elsevier Science B.V. All rights reserved.

Localization of taurine transporters, taurine, and H-3 taurine accumulation in the rat retina, pituitary, and brain

The nervous system contains an abundance of taurine, a neuroactive sulfonic acid. Antibodies were generated against two cloned high-affinity taurine transporters, referred to in this study as TAUT-1 and TAUT-2. The distribution of such was compared with the distribution of taurine in the rat brain, pituitary, and retina. The cellular pattern of [H-3] taurine uptake in brain slices, pituitary slices, and retinas was examined by autoradiography. TAUT-2 was predominantly associated with glial cells, including the Bergmann glial cells of the cerebellum and astrocytes in brain areas such as hippocampus. Low-level labeling for TAUT-2 was also observed in some neurones such as CA1 pyramidal cells. TAUT-1 distribution was more limited; in the posterior pituitary TAUT-1 was associated with the pituicytes but was absent from glial cells in the intermediate and anterior lobes. Conversely, in the brain TAUT-1 was associated with cerebellar Purkinje cells and, in the retina, with photoreceptors and bipolar cells. Our data suggest that intracellular taurine levels in glial cells and neurons may be regulated in part by specific high-affinity taurine transporters. The heterogeneous distribution of taurine and its transporters in the brain does not reconcile well with the possibility that taurine acts solely as a ubiquitous osmolyte in nervous tissues. (C) 2002 Wiley-Liss, Inc.

Nitrate ammonification and its relationship to the accumulation of ammonium in a Vertisol subsoil

High concentrations of ammonium ( up to 270 kg N/ha) have been observed in a Vertisol soil below 1 m depth near Warra in south-east Queensland. This study examined the possibility that increased water movement into the subsoil after the removal of native vegetation, and a subsequent increase in periods of waterlogging, could have triggered nitrate ammonification and be responsible for the production of ammonium. Two incubation experiments were conducted to test this hypothesis. The first involved the incubation of repacked cores that had been amended with 30 mg N/kg of 5 atom% N-15 nitrate under low oxygen conditions for a period of 360 days. Over this time period the N-15 enrichment of the exchangeable ammonium fraction was monitored in order to detect any reduction of nitrate to ammonium. The second experiment involved the incubation of soil amended with 30 mg N/ kg of 5 atom% N-15 nitrate under waterlogged and low oxygen conditions for 75 days. During this period the redox potential of the soil was monitored using a field test to determine if reducing conditions would develop in this soil over a period of waterlogging, combined with the monitoring of any nitrate reduction to ammonium. The results of these experiments indicated that a small amount of nitrate ammonification (< 0.1 mg N/ kg) could be observed in the Warra subsoil, but that unless the rate of reduction were to significantly increase with time, this could not account for the accumulation of ammonium observed in the field. The environmental conditions that would make either dissimilatory or abiotic nitrate ammonification favourable were not observed to develop. Consequently, it has been concluded that the observed nitrate ammonification occurred via an assimilatory pathway. Due to the low rate of microbial activity in this subsoil it is considered unlikely that this process was responsible for the subsoil ammonium accumulation at Warra.

Nutrient accumulation and biomass production of alfafa after soil amendment with silicates

Studies on the use of silicate correctives in agriculture show that they have great potential to improve soil chemical characteristics, however, little information is available on the reactivity rates of their particle-size fractions. This study investigated whether the reactivity rates obtained experimentally could be considered in the calculation of ECC (effective calcium carbonate) for soil liming, promoting adequate development of alfalfa plants. Six treatments were evaluated in the experiment, consisting of two slag types applied in two rates. The experimental ECC was used to calculate one of the rates and the ECC determined in the laboratory was used to calculate the other. Rates of limestone and wollastonite were based on the ECC determined in laboratory. The rates of each soil acidity corretive were calculated to increase the base saturation to 80%. The treatments were applied to a Rhodic Hapludox and an Alfisol Ferrudalfs. The methods for ECC determination established for lime can be applied to steel slag. The application of slag corrected soil acidity with consequent accumulation of Ca, P, and Si in alfalfa, favoring DM production.

STRATEGIC DECISIONS OF FAMILY FIRMS ON CASH ACCUMULATION

ABSTRACTGiven the particular strengths, weaknesses, and peculiarities of family firms as well as the importance of liquidity in today’s marketplace, we analyze the distinct characteristics and strategies of family businesses related to the amount of cash a firm holds. We look beyond the traditional factors that influence decisions related to cash management to examine factors that are particularly important for family firms. Specifically, we outline the relevance of strategic decisions guided by family firms’ conservatism, flexibility, long-term view, and the active control that they have over family members. To our knowledge, no prior studies exist regarding family firms and their strategic adjustment of cash holding. Therefore, we investigate whether the ownership structure of the firm (through the presence of a controlling family) moderates decisions on cash holding. We found that family firms tend to accumulate cash for strategic reasons and as a result of their own idiosyncrasies. Thus, family firms can achieve optimal cash accumulation more efficiently than non-family firms.