bluuebunny/crossref_metadata_2025_split huggingface dataset:
Replicative Aging, Telomeres, and Oxidative Stress
Authors: SARETZKI GABRIELE , VON ZGLINICKI THOMAS 
Published: July 2010

AbstractAging is a very complex phenomenon, both in vivo and in vitro. Free radicals and oxidative stress have been suggested for a long time to be involved in or even to be causal for the aging process. Telomeres are special structures at the end of chromosomes. They shorten during each round of replication and this has been characterized as a mitotic counting mechanism. Our experiments show that the rate of telomere shortening in vitro is modulated by oxidative stress as well as by differences in antioxidative defence capacity between cell strains. In vivo we found a strong correlation between short telomeres in blood lymphocytes and the incidence of vascular dementia. These data suggest that parameters that characterise replicative senescence in vitro offer potential for understanding of, and intervention into, the aging process in vivo.
Exercise‐induced Modulation of Antioxidant Defense
Authors: JI LI LI 
Published: July 2010

AbstractMaintaining mobility is a critical element for the quality of life. Skeletal muscle, the primary organ for locomotion, undergoes age‐associated deterioration in size, structure, and function. Recent research suggests that oxidative stress is an important etiology for sarcopenia. The level of oxidative stress imposed on aging muscle is influenced by two fundamental biological processes: the increased generation of reactive oxygen species (ROS) and age‐associated changes in antioxidant defense. It appears that despite increased ROS production, aging muscle has a decreased gene expression of antioxidant enzymes possibly due to a diminished ability for cell signaling. A major benefit of nonexhaustive exercise is to induce a mild oxidative stress that stimulates the expression of certain antioxidant enzymes. This is mediated by the activation of redox‐sensitive signaling pathways. For example, gene expression of muscle mitochondrial (Mn) superoxide dismutase is enhanced after an acute bout of exercise preceded by an elevated level of NF‐κB and AP‐1 binding. An increase in de novo protein synthesis of an antioxidant enzyme usually requires repeated bouts of exercise. Aging does not abolish but seems to attenuate training adaptations of antioxidant enzymes. Thus, for senescent muscle, training should be assisted with supplementation of exogenous antioxidants to research the optimal level of defense.
Generation of Reactive Oxygen and Nitrogen Species in Contracting Skeletal Muscle
Authors: REID MICHAEL B. , DURHAM WILLIAM J. 
Published: July 2010

AbstractSince the early 1980s biologists have recognized that skeletal muscle generates free radicals. Of particular interest are two closely related redox cascades—reactive oxygen species (ROS) and nitric oxide (NO) derivatives. The ROS cascade is initiated by superoxide anion radicals derived from the mitochondrial electron transport chain, the membrane‐associated NAD(P)H oxidase complex, or other sources. NO is produced by two NO synthase isoforms constitutively expressed by muscle fibers. ROS and NO derivatives are produced continually and are detectable in both the cytosolic and extracellular compartments. Production increases during strenuous exercise. Both ROS and NO modulate contractile function. Under basal conditions, low levels of ROS enhance force production. Excessive ROS accumulation inhibits force, for example, during fatiguing exercise. NO inhibits skeletal muscle contraction, an effect that is partially mediated by cyclic GMP as a second messenger. With aging, redox modulation of muscle contraction may be altered by changes in the rates of ROS and NO production, the levels of endogenous antioxidants that buffer ROS and NO, and the sensitivities of regulatory proteins to ROS and NO action. The impact of aging on contractile regulation depends on the relative magnitude of these changes and their net effects on ROS and NO activities at the cellular level.
Enhancing Cognitive Function across the Life Span
Authors: KOROL DONNA L. 
Published: July 2010

AbstractGlucose administration regulates many neural and behavioral processes in rodents, including learning and memory. Given the important role of glucose in brain function and the safety of glucose as a treatment, we have investigated the effects of glucose administration in humans of different ages. In previous work, we examined the effects of early‐morning glucose consumption on cognitive functions in elderly individuals. In this population, glucose enhanced performance on specific measures, particularly on those tasks where mild age‐related deficits appear (e.g., verbal declarative memory). Interestingly, glucose failed to enhance cognitive functions in young adults. Our recent work has examined three issues related to glucose enhancement of cognition: First, is glucose effective only in reversing impairments or can it also facilitate performance in highly functioning individuals? Second, are glucose effects dependent either on time of day or on interactions with other meals? Third, are typical breakfast foods as effective as glucose in enhancing cognitive performance? Our findings suggest that glucose can improve memory in highly functioning populations as it does in populations with deficits. However, enhancement by glucose may require sufficient levels of task difficulty and of blood glucose. In addition, like glucose, early morning consumption of cereal can improve performance on some cognitive tests. These results have important implications for the nature of glucose facilitation of memory and for the role of dietary factors in performance of many daily activities.
Nitrones as Neuroprotectants and Antiaging Drugs
Authors: FLOYD ROBERT A. , HENSLEY KENNETH , FORSTER MICHAEL J. , KELLEHER‐ANDERSON JUDITH A. , WOOD PAUL L. 
Published: July 2010

AbstractSpecific nitrones have been used for more than 30 years in analytical chemistry and biochemistry to trap and stabilize free radicals for the purpose of their identification and characterization. PBN (α‐phenyl‐tert‐butyl nitrone), one of the more widely used nitrones for this purpose, has been shown to have potent pharmacologic activities in models of a number of aging‐related diseases, most notably the neurodegenerative diseases of stroke and Alzheimer's disease. Studies in cell and animal models strongly suggest that PBN has potent antiaging activity. A novel nitrone, CPI‐1429, has been shown to extend the life span of mice when administration was started in older animals. It has also shown efficacy in the prevention of memory dysfunction associated with normal aging in a mouse model. Mechanistic studies have shown that the neuroprotective activity of nitrones is not due to mass‐action free radical‐trapping activity, but due to cessation of enhanced signal transduction processes associated with neuroinflammatory processes known to be enhanced in several neurodegenerative conditions. Enhanced neuroinflammatory processes produce higher levels of neurotoxins, which cause death or dysfunction of neurons. Therefore, quelling of these processes is considered to have a beneficial effect allowing proper neuronal functioning. The possible antiaging activity of nitrones may reside in their ability to quell enhanced production of reactive oxygen species associated with age‐related conditions. On the basis of novel ideas about the action of secretory products formed by senescent cells on bystander cells, it is postulated that nitrones will mitigate these processes and that this may be the mechanism of their antiaging activity.
Involvement of Mitochondria and Other Free Radical Sources in Normal and Abnormal Fetal Development
Authors: FANTEL ALAN G. , PERSON RICHARD E. 
Published: July 2010

AbstractShepard and Mackler have documented quantitative increases in mitochondrial cristae between gestational days 10 and 14 in rats accompanied by decreased glucose utilization and increased NADH oxidase activity. Findings show a shift from glycolytic to oxidative metabolism starting at around the time of implantation. Exposure to many substances that cause transient uteroplacental hypoperfusion, including cocaine, phenytoin, calcium channel blockers, and nitric oxide synthase (NOS) inhibitors, induce limb and central nervous system (CNS) malformations while sparing the heart. We have reported that isolated electron transport particles prepared from sensitive tissues show reduced NADH oxidase activities compared with insensitive heart. They also have significantly greater superoxide formation in association with significantly reduced superoxide dismutase activities. NOS inhibitors induce severe limb reductions in late gestation. Exposure is associated with hemorrhage and nitrotyrosine (NT) formation shortly after treatment. Hemorrhage, malformations, and NT formation can be significantly reduced by coadministration of PBN, allopurinol, or aminoguanidine. On the basis of these findings, we have proposed a role for the formation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the genesis of limb reduction defects. It is important to note that limb reduction defects occur in humans (∼0.22/1000) and have been associated with the agents listed above.
Frequent Intracellular Clonal Expansions of Somatic mtDNA Mutations
Authors: COLLER HILARY A. , BODYAK NATALYA D. , KHRAPKO KONSTANTIN 
Published: July 2010

AbstractIt has been proposed that age‐dependent accumulation of somatic mutations in mtDNA is responsible for some aspects of the aging process. However, most cells contain hundreds to thousands of mtDNA molecules. Any nascent somatic mutant therefore appears as a single copy among a majority of wild‐type species. A single mutant molecule is unlikely to influence the physiology of the cell and thus cannot play a role in the aging process. To affect cellular physiology, the nascent somatic mutants must somehow accumulate clonally in the cell to significant levels. The evidence supporting the view that, indeed, clonal expansion of mtDNA mutations is a widespread process in various human tissues, and the mechanisms by which clonal expansions may affect the aging process, are reviewed. Originally, clonal expansion was demonstrated for mtDNA with large deletions in muscle. Cell‐by‐cell analysis of human cardiomyocytes and buccal epithelial cells revealed that clonal expansion affects point mtDNA mutations as well as deletions. Expansions are not limited to muscle, but likely are present in most tissues, and almost every cell of an aged tissue is likely to be affected by an expansion. While the very existence of clonal expansion is beyond doubt, the mechanisms driving this process are largely controversial. The hypotheses explaining expansion includes random or various selective mechanisms, or both. We show that the spectra of expanded point mutations are drastically different in cardiomyocytes and epithelial cells. This suggests that the mechanisms of expansion in these tissues are different. In particular, we propose random segregation and positive selection models for epithelial and muscle cells, respectively.
A Novel Method for Simultaneous and Continuous Determination of Thermal Properties during Phase Transition Applied to Calanus finmarchicus
Authors: Bantle Michael , Eikevik Trygve Magne , Brennvall Jon Eirik 
Published: July 2010

Abstract:  The thermal properties of a product are the most important parameters for practical engineering purposes and models in food science. Calanus finmarchicus is currently being examined as a marine resource for uncommon aquatic lipids and proteins. Thermal conductivity, specific heat, enthalpy and density were measured over the temperature range from −40 to +20 °C. The initial freezing point was determined to be −2.3 °C. The thermal properties were recorded continuously on 4 samples using a new method, and the results were compared with predictive models. The accuracy of the new method is demonstrated by different calibration runs. Significant differences in the thermal conductivity of the frozen material were found between the parallel‐series model and the data, whereas the model of Pham and Willix (1989) or the Maxwell–Euken adaption showed better agreement. The measured data for specific heat, enthalpy, and density agreed well with the model.Practical Application:  The thermal data obtained can be used directly in food engineering and technology applications, for example, in a thin layer model for freezing food for which precise thermal data for each layer are now available, enabling the more accurate prediction of freezing times and temperature profiles. Dimensionless numbers (such as the Biot number) can also be based on measured data with minor deviations compared to more general modeled thermal properties. Future activities will include the generation of a comprehensive database for different products.
Bowel obstruction associated with endoscopic tattooing of the colon with India ink
Authors: Seki Y , Sekimoto M , Noura S , Takemasa I , Ikeda M , Yamamoto H , Doki Y , Mori M 
Published: July 2010

AbstractDuring a laparoscopic resection of small colorectal lesions, preoperative endoscopic marking with India ink is useful for identifying the location of the lesion. India ink has been thought to be a safe agent with few adverse effects. We herein report a case who suffered from postoperative abdominal pain resulting in bowel obstruction, due to massive adhesion around the area with India ink. A 61‐year‐old man with early transverse colon cancer underwent a laparoscopy‐assisted transverse colon resection. Prior to the operation, endoscopic tattooing with India ink was performed. At the operation, spillage of India ink into the peritoneal cavity was observed. Many small black spots were thereafter seen on the peritoneum, mesentery and omentum, but neither severe inflammation nor any adhesion was noticed. The operation was performed without any difficulty. Though his immediate postoperative course was uneventful, a bowel obstruction gradually developed from a week postoperatively. Finally, he had to undergo a re‐operation, and was found to have diffuse and massive adhesion around areas with India ink. Especially, severe omental adhesion involved and squeezed the transverse colon. A resection of the omentum with stenotic colon and re‐anastomosis was performed. India ink can cause severe inflammation and adhesion when it accidentally leaks into the peritoneal cavity.
Effect of poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) micelles on pharmacokinetics and intestinal toxicity of irinotecan hydrochloride: potential involvement of breast cancer resistance protein (ABCG2)
Authors: Guo Shiyan , Zhang Xinxin , Gan Li , Zhu Chunliu , Gan Yong 
Published: July 2010

Abstract

Objectives
Intestinal toxicity and low levels of systemic drug exposure are among the major problems associated with tumour therapy. We have developed poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) (PEO-PPO-PEO) micelles loaded with irinotecan hydrochloride (CPT-11) hoping to decrease CPT-11-induced intestinal toxicity while increasing its systemic exposure. In addition, we have investigated the potential involvement of breast cancer resistance protein (BCRP) in biliary excretion, pharmacokinetics, and intestinal toxicity of CPT-11.

Methods
PEO-PPO-PEO micelles were prepared using PEO20-PPO70-PEO20 and lecithin. The effect of PEO-PPO-PEO micelles on BCRP-mediated cellular accumulation and transport efflux of CPT-11 was evaluated in MDCKII/BCRP cells. The biliary excretion, intestinal damage, and pharmacokinetic study of CPT-11-loaded PEO-PPO-PEO micelles were investigated in rats.

Key findings
The obtained micelles could effectively inhibit BCRP-mediated CPT-11 efflux in MDCKII/BCRP cells, and significantly decrease the drug biliary excretion in rats. Moreover, intestinal toxicity, assessed by microscopic examination of pathological damage, was ameliorated in rats injected with PEO-PPO-PEO micelles compared with rats injected with CPT-11 alone. Treatment with PEO-PPO-PEO micelles resulted in prolonged circulation time in blood and increased bioavailability of CPT-11 and SN-38 (7-ethyl-10-hydroxycamptothecin).

Conclusions
PEO-PPO-PEO micelles were identified as promising carriers able to reduce intestinal toxicity and increase antitumour therapeutic effect of CPT-11. The study indicated a potential involvement of BCRP in CPT-11 pharmacokinetics and CPT-11-induced intestinal toxicity.
Antineoplastic effect of β-elemene on prostate cancer cells and other types of solid tumour cells
Authors: Li Qingdi Quentin , Wang Gangduo , Huang Furong , Banda Malathi , Reed Eddie 
Published: July 2010

Abstract

Objectives
β-Elemene, a natural compound extracted from over 50 different Chinese medicinal herbs and plants, has been effective in the treatment of hyperplastic and proliferative disorders such as prostatic hypertrophy, hysteromyoma and neoplasms. Our previous studies have demonstrated that β-elemene exhibits strong inhibitory activity in ovarian cancer cells. The aim of the present study was to assess the effect of β-elemene on prostate cancer cells as well as other types of tumour cells and to determine whether the effect of β-elemene on prostate cancer cell death was mediated through the induction of apoptosis.

Methods
The MTT assay was used to evaluate the ability of β-elemene to inhibit cellular proliferation in cancer cells. Cellular apoptosis was assessed by annexin V binding, TUNEL and ELISA-based assays. Caspase activity was measured using a caspases assay kit. The protein levels of Bcl-2, caspases, cytochrome c and poly(ADP-ribose) polymerase (PARP) were analysed by Western blotting.

Key findings
Here, we showed that β-elemene had an antiproliferative effect on androgen-insensitive prostate carcinoma DU145 and PC-3 cells. Treatment with β-elemene also inhibited the growth of brain, breast, cervical, colon and lung carcinoma cells. The effect of β-elemene on cancer cells was dose dependent, with IC50 values ranging from 47 to 95 µg/ml (230–465 µm). TUNEL assay and flow cytometric analysis using annxin V/propidium iodide staining revealed that the percentage of apoptotic prostate cancer cells was increased by β-elemene in a dose- and time-dependent manner. Moreover, β-elemene exposure resulted in a decreased Bcl-2 protein level, increased cytochrome c release, and activated PARP and caspase-3, -7, -9, and -10 in prostate cancer cells.

Conclusions
Overall, these findings suggest that β-elemene exerts broad-spectrum antitumour activity against many types of solid carcinoma and supports a proposal of β-elemene as a new potentially therapeutic drug for castration-resistant prostate cancer and other solid tumours.
A Model for Improved Prediction of Force Coefficients in Grooved Squeeze Film Dampers and Oil Seal Rings
Authors: Delgado Adolfo , San Andrés Luis 
Published: July 2010

Abstract
Squeeze film damper (SFD) designs typically implement supply grooves to ensure adequate lubricant flow into the film lands. Oil seal rings, of land film clearance c, also incorporate short and shallow grooves (length≤30c,depth≤15c) to reduce cross-coupled stiffnesses, thus promoting dynamic stability without a penalty in increased leakage. However, extensive experimental results in the archival literature demonstrate that grooves do not reduce the force coefficients as much as theory predicts. A common assumption is that deep grooves do not influence a damper or oil seal ring forced response. However, unexpected large added mass coefficients, not adequately predicted, appear to be common in many tested SFD and oil seal configurations. In the case of oil seals, experiments demonstrate that circumferential grooves do reduce cross-coupled stiffnesses but to a lesser extent than predictions would otherwise indicate. A linear fluid inertia bulk-flow model for analysis of the forced response of SFDs and oil seal configurations with multiple grooves is advanced. A perturbation analysis for small amplitude journal motions about a centered position yields zeroth and first-order flow equations at each flow region (lands and grooves). At a groove region, a groove effective depth dη, differing from its actual physical value, is derived from qualitative observations of the laminar flow pattern through annular cavities. The boundary conditions at the inlet and exit planes depend on the actual seal or SFD configuration. Integration of the resulting first-order pressure fields on the journal surface yields the force coefficients (stiffness, damping, and inertia). Current model predictions are in excellent agreement with published test force coefficients for a grooved SFD and a grooved oil seal. The results confirm that large added mass coefficients arise from the flow interactions between the feed/discharge grooves and film lands in the test elements. Furthermore, the predictions, benchmarking experimental data, corroborate that short length inner-land grooves in an oil seal do not isolate the pressure fields of adjacent film lands and hence contribute greatly to the forced response of the mechanical element.