bluuebunny/crossref_metadata_2025 huggingface dataset:
Exercise restores coronary vascular function independent of myogenic tone or hyperglycemic status indb/dbmice
Authors: Moien-Afshari Farzad , Ghosh Sanjoy , Elmi Shahrzad , Khazaei Majid , Rahman Mohammad M. , Sallam Nada , Laher Ismail
Published: July 2008

Regulation of coronary function in diabetic hearts is an important component in preventing ischemic cardiac events but remains poorly studied. Exercise is recommended in the management of diabetes, but its effects on diabetic coronary function are relatively unknown. We investigated coronary artery myogenic tone and endothelial function, essential elements in maintaining vascular fluid dynamics in the myocardium. We hypothesized that exercise reduces pressure-induced myogenic constriction of coronary arteries while improving endothelial function in db/db mice, a model of type 2 diabetes. We used pressurized mouse coronary arteries isolated from hearts of control and db/db mice that were sedentary or exercised for 1 h/day on a motorized exercise-wheel system (set at 5.2 m/day, 5 days/wk). Exercise caused a ∼10% weight loss in db/db mice and decreased whole body oxidative stress, as measured by plasma 8-isoprostane levels, but failed to improve hyperglycemia or plasma insulin levels. Exercise did not alter myogenic regulation of arterial diameter stimulated by increased transmural pressure, nor did it alter smooth muscle responses to U-46619 (a thromboxane agonist) or sodium nitroprusside (an endothelium-independent dilator). Moderate levels of exercise restored ACh-simulated, endothelium-dependent coronary artery vasodilation in db/db mice and increased expression of Mn SOD and decreased nitrotyrosine levels in hearts of db/db mice. We conclude that the vascular benefits of moderate levels of exercise were independent of changes in myogenic tone or hyperglycemic status and primarily involved increased nitric oxide bioavailability in the coronary microcirculation.
Kinetics of fluid flux in the rat diaphragmatic submesothelial lymphatic lacunae
Authors: Moriondo Andrea , Bianchin Francesca , Marcozzi Cristiana , Negrini Daniela
Published: July 2008

The specific role of loops and/or linear segments in pleural diaphragmatic submesothelial lymphatics was investigated in seven anesthetized, paralyzed, and mechanically ventilated rats. Lymphatic loops lay peripherally above the diaphragmatic muscular plane, whereas linear vessels run over both the muscular and central tendineous regions. Lymph vessel diameter, measured by automatic software analysis, was significantly greater ( P < 0.01) in linear vessels [103.4 ± 8.5 μm (mean ± SE), n = 18] than in loops (54.6 ± 3.3 μm, n = 21). Conversely, the geometric mean of intraluminal flow velocity, obtained from the speed of distribution of a bolus of fluorescent dextrans injected into the vessel, was lower ( P < 0.01) in linear vessels (26.3 ± 1.4 μm/s) compared with loops (51.3 ± 3.2 μm/s). Lymph flow, calculated as the product of flow velocity by vessel cross-sectional area, was similar in linear vessels and in individual vessels of a loop, averaging 8.6 ± 1.6 nl/min. Flow was always directed from the diaphragm periphery toward the medial tendineous region in linear vessels, whereas it was more complex and evidently controlled by intraluminal unidirectional valves in loops. The results suggest that loops might be the preferential site of lymph formation, whereas linear vessels would be mainly involved in the progression of newly formed lymph toward deeper collecting diaphragmatic ducts. Within the same hierarchic order of diaphragmatic lymphatic vessels, the spatial organization and geometrical arrangement of the submesothelial lacunae seem to be finalized at exploiting the alternate contraction/relaxation phases of diaphragmatic muscle fibers to optimize fluid removal from serosal cavities.
Leukocyte-endothelial cell interactions are linked to vascular permeability via ICAM-1-mediated signaling
Authors: Sumagin Ronen , Lomakina Elena , Sarelius Ingrid H.
Published: July 2008

Two key characteristics of the inflammatory response are the recruitment of leukocytes to inflamed tissue as well as changes in vessel permeability. We explored the relationship between these two processes using intravital confocal microscopy in cremasters of anesthetized (65 mg/kg Nembutal ip) mice. We provide direct evidence that intercellular adhesion molecule-1 (ICAM-1) links leukocyte-endothelial cell interactions and changes in solute permeability ( Ps). Importantly, we show that arterioles, not just venules, respond to proinflammatory stimuli, thus contributing to microvascular exchange. We identified two independent, ICAM-1-mediated pathways regulating Ps. Under control conditions in wild-type (WT) mice, there is a constitutive PKC-dependent pathway ( Ps = 1.0 ± 0.10 and 2.2 ± 0.46 × 10−6 cm/s in arterioles and venules, respectively), which was significantly reduced in ICAM-1 knockout (KO) mice ( Ps = 0.54 ± 0.07 and 0.77 ± 0.11 × 10−6 cm/s). The PKC inhibitor bisindolylmaleimid l (1 μmol/l in 0.01% DMSO) decreased Ps in WT mice to levels similar to those in ICAM-1 KO mice. Likewise, a PKC activator (phorbol-12-myristate-acetate; 1 μmol/l in 0.01% DMSO) successfully restored Ps in ICAM-1 KO vessels to be not different from that of the WT controls. On the other hand, during TNF-α-induced inflammation, Ps in WT mice was significantly increased (2-fold in venules and 2.5-fold in arterioles) in a Src-dependent and PKC-independent manner. The blockade of Src (PP2; 2 μmol/l in 0.01% DMSO) but not PKC significantly reduced the TNF-α-dependent increase in Ps. We conclude that ICAM-1 plays an essential role in the regulation of Ps in microvessels and that there are two separate (constitutive and inducible) signaling pathways that regulate permeability under normal and inflamed conditions.
Prevention of aortic fibrosis byN-acetyl-seryl-aspartyl-lysyl-proline in angiotensin II-induced hypertension
Authors: Lin Chun-Xia , Rhaleb Nour-Eddine , Yang Xiao-Ping , Liao Tang-Dong , D'Ambrosio Martin A. , Carretero Oscar A.
Published: July 2008

Fibrosis is an important component of large conduit artery disease in hypertension. The endogenous tetrapeptide N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) has anti-inflammatory and antifibrotic effects in the heart and kidney. However, it is not known whether Ac-SDKP has an anti-inflammatory and antifibrotic effect on conduit arteries such as the aorta. We hypothesize that in ANG II-induced hypertension Ac-SDKP prevents aortic fibrosis and that this effect is associated with decreased protein kinase C (PKC) activation, leading to reduced oxidative stress and inflammation and a decrease in the profibrotic cytokine transforming growth factor-β1 (TGF-β1) and phosphorylation of its second messenger Smad2. To test this hypothesis we used rats with ANG II-induced hypertension and treated them with either vehicle or Ac-SDKP. In this hypertensive model we found an increased collagen deposition and collagen type I and III mRNA expression in the aorta. These changes were associated with increased PKC activation, oxidative stress, intercellular adhesion molecule (ICAM)-1 mRNA expression, and macrophage infiltration. TGF-β1 expression and Smad2 phosphorylation also increased. Ac-SDKP prevented these effects without decreasing blood pressure or aortic hypertrophy. Ac-SDKP also enhanced expression of inhibitory Smad7. These data indicate that in ANG II-induced hypertension Ac-SDKP has an aortic antifibrotic effect. This effect may be due in part to inhibition of PKC activation, which in turn could reduce oxidative stress, ICAM-1 expression, and macrophage infiltration. Part of the effect of Ac-SDKP could also be due to reduced expression of the profibrotic cytokine TGF-β1 and inhibition of Smad2 phosphorylation.
Three-dimensional transmural organization of perimysial collagen in the heart
Authors: Pope Adèle J. , Sands Gregory B. , Smaill Bruce H. , LeGrice Ian J.
Published: July 2008

There is strong support for the view that the ventricular myocardium has a laminar organization in which myocytes are grouped into branching layers separated by cleavage planes. However, understanding of the extent and functional implications of this architecture has been limited by the lack of a systematic three-dimensional description of the organization of myocytes and associated perimysial collagen. We imaged myocytes and collagen across the left ventricular wall at high resolution in seven normal rat hearts using extended volume confocal microscopy. We developed novel reconstruction and segmentation techniques necessary for the quantitative analysis of three-dimensional myocyte and perimysial collagen organization. The results confirm that perimysial collagen has an ordered arrangement and that it defines a laminar organization. Perimysial collagen is composed of three distinct forms: extensive meshwork on laminar surfaces, convoluted fibers connecting adjacent layers, and longitudinal cords. While myolaminae are the principal form of structural organization throughout most of the wall, they are not seen in the subepicardium, where perimysial collagen is present only as longitudinal cords.
Role of P2X purinergic receptors in the rescue of ischemic heart failure
Authors: Sonin Dmitry , Zhou Si-Yuan , Cronin Chunxia , Sonina Tatiana , Wu Jeffrey , Jacobson Kenneth A. , Pappano Achilles , Liang Bruce T.
Published: July 2008

Evidence is accumulating to support the presence of P2X purinergic receptors in the heart. However, the biological role of this receptor remains to be defined. The objectives here were to determine the role of cardiac P2X receptors in modulating the progression of post-myocardial infarction ischemic heart failure and to investigate the underlying mechanism. The P2X4receptor (P2X4R) is an important subunit of native cardiac P2X receptors, and the cardiac-specific transgenic overexpression of P2X4R (Tg) was developed as a model. Left anterior descending artery ligation resulted in similar infarct size between Tg and wild-type (WT) mice ( P > 0.1). However, Tg mice showed an enhanced cardiac contractile performance at 7 days, 1 mo, and 2 mo after infarction and an increased survival at 1 and 2 mo after infarction ( P < 0.01). The enhanced intact heart function was manifested by a greater global left ventricular developed pressure and rate of contraction of left ventricular pressure in vitro and by a significantly increased fractional shortening and systolic thickening in the noninfarcted region in vivo ( P < 0.05). The salutary effects on the ischemic heart failure phenotype were seen in both sexes and were not the result of any difference in infarct size in Tg versus WT hearts. An enhanced contractile function of the noninfarcted area in the Tg heart was likely an important rescuing mechanism. The cardiac P2X receptor is a novel target to treat post-myocardial infarction ischemic heart failure.
Evidence for functional alterations in the skeletal muscle mechanoreflex and metaboreflex in hypertensive rats
Authors: Leal Anna K. , Williams Maurice A. , Garry Mary G. , Mitchell Jere H. , Smith Scott A.
Published: July 2008

Exercise in hypertensive individuals elicits exaggerated increases in mean arterial pressure (MAP) and heart rate (HR) that potentially enhance the risk for adverse cardiac events or stroke. Evidence suggests that exercise pressor reflex function (EPR; a reflex originating in skeletal muscle) is exaggerated in this disease and contributes significantly to the potentiated cardiovascular responsiveness. However, the mechanism of EPR overactivity in hypertension remains unclear. EPR function is mediated by the muscle mechanoreflex (activated by stimulation of mechanically sensitive afferent fibers) and metaboreflex (activated by stimulation of chemically sensitive afferent fibers). Therefore, we hypothesized the enhanced cardiovascular response mediated by the EPR in hypertension is due to functional alterations in the muscle mechanoreflex and metaboreflex. To test this hypothesis, mechanically and chemically sensitive afferent fibers were selectively activated in normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) decerebrate rats. Activation of mechanically sensitive fibers by passively stretching hindlimb muscle induced significantly greater increases in MAP and HR in SHR than WKY over a wide range of stimulus intensities. Activation of chemically sensitive fibers by administering capsaicin (0.01–1.00 μg/100 μl) into the hindlimb arterial supply induced increases in MAP that were significantly greater in SHR compared with WKY. However, HR responses to capsaicin were not different between the two groups at any dose. This data is consistent with the concept that the abnormal EPR control of MAP described previously in hypertension is mediated by both mechanoreflex and metaboreflex overactivity. In contrast, the previously reported alterations in the EPR control of HR in hypertension may be principally due to overactivity of the mechanically sensitive component of the reflex.
Differential antiproliferative mechanisms of novel derivative of benzimidazo[1,2-α]quinoline in colon cancer cells depending on their p53 status
Authors: Sedic Mirela , Poznic Miroslav , Gehrig Peter , Scott Mike , Schlapbach Ralph , Hranjec Marijana , Karminski-Zamola Grace , Pavelic Kresimir , Pavelic Sandra Kraljevic
Published: July 2008

In the present article, we describe a mechanistic study of a novel derivative of N-amidino-substituted benzimidazo[1,2-α]quinoline in two human colorectal cancer cell lines differing in p53 gene status. We used a proteomic approach based on two-dimensional gel electrophoresis coupled with mass spectrometry to complement the results obtained by common molecular biology methods for analyzing cell proliferation, cell cycle, and apoptosis. Tested quinoline derivative inhibited colon cancer cell growth, whereby p53 gene status seemed to be critical for its differential response patterns. DNA damage and oxidative stress are likely to be the common triggers of molecular events underlying its antiproliferative effects. In HCT 116 (wild-type p53), this compound induced a p53-dependent response resulting in accumulation of the G1- and S-phase cells and induction of apoptosis via both caspase-3-dependent and caspase-independent pathways. Quinoline derivative triggered transient, p53-independent G2-M arrest in mutant p53 cells (SW620) and succeeding mitotic transition, whereby these cells underwent cell death probably due to aberrant mitosis (mitotic catastrophe). Proteomic approach used in this study proved to be a valuable tool for investigating cancer cell response to newly synthesized compound, as it specifically unraveled some molecular changes that would not have been otherwise detected (e.g., up-regulation of the p53-dependent chemotherapeutic response marker maspin in HCT 116 and impairment in ribosome biogenesis in SW620). Finally, antiproliferative effects of tested quinoline derivative on SW620 cells strongly support its possible role as an antimetastatic agent and encourage further in vivo studies on the chemotherapeutic potential of this compound against colorectal carcinoma. [Mol Cancer Ther 2008;7(7):2121–32]
A rationally designed tyrosine hydroxylase DNA vaccine induces specific antineuroblastoma immunity
Authors: Huebener Nicole , Fest Stefan , Strandsby Anne , Michalsky Elke , Preissner Robert , Zeng Yan , Gaedicke Gerhard , Lode Holger N.
Published: July 2008

Therapeutic vaccination against tumor antigens without induction of autoimmunity remains a major challenge in cancer immunotherapy. Here, we show for the first time effective therapeutic vaccination followed by suppression of established spontaneous neuroblastoma metastases using a tyrosine hydroxylase (TH) DNA minigene vaccine. We identified three novel mouse TH (mTH3) derived peptides with high predicted binding affinity to MHC class I antigen H2-Kk according to the prediction program SYFPEITHI and computer modeling of epitopes into the MHC class I antigen binding groove. Subsequently, a DNA minigene vaccine was generated based on the expression vector pCMV-F3Ub encoding mutated ubiquitin (Gly76 to Ala76) and mTH3. Prophylactic and therapeutic efficacies of this vaccine were established following oral delivery with attenuated Salmonella typhimurium SL7207. Only mice immunized with mTH3 were free of spontaneous liver metastases. This effect was clearly dependent on ubiquitin and high affinity of the mTH epitopes to MHC class I antigens. Specifically, we showed a crucial role for minigene expression as a stable ubiquitin-Ala76 fusion peptide for vaccine efficacy. The immune response following the mTH3 DNA minigene vaccination was mediated by CD8+ T cells as indicated by infiltration of primary tumors and TH-specific cytolytic activity in vitro. Importantly, no cell infiltration was detectable in TH-expressing adrenal medulla, indicating the absence of autoimmunity. In summary, we show effective therapeutic vaccination against neuroblastoma with a novel rationally designed TH minigene vaccine without induction of autoimmunity providing an important baseline for future clinical application of this strategy. [Mol Cancer Ther 2008;7(7):2241–51]
Activity of lapatinib is independent of EGFR expression level in HER2-overexpressing breast cancer cells
Authors: Zhang Dongwei , Pal Ashutosh , Bornmann William G. , Yamasaki Fumiyuki , Esteva Francisco J. , Hortobagyi Gabriel N. , Bartholomeusz Chandra , Ueno Naoto T.
Published: July 2008

Epidermal growth factor receptor (EGFR/ErbB1) and HER2 (ErbB2/neu), members of the ErbB receptor tyrosine kinase family, are frequently overexpressed in breast cancer and are known to drive tumor growth and progression, making them promising targets for cancer therapy. Lapatinib is a selective competitive inhibitor of both the HER2 and EGFR tyrosine kinases. Although lapatinib showed significant activity in patients with HER2-positive breast cancer, the role of EGFR in the response of breast cancer to lapatinib has not been defined. Here, we examined the role of EGFR expression levels in the sensitivity of HER2-overexpressing breast cancer cells to lapatinib. Depletion of EGFR by EGFR small-interfering RNA knockdown did not affect lapatinib sensitivity in these cells, whereas treated HER2 siRNA knockdown cells became more resistant to lapatinib. We conclude that the in vitro activity of lapatinib is not dependent on EGFR expression level in HER2-overexpressing breast cancer cells. [Mol Cancer Ther 2008;7(7):1846–50]
Role of Activating Transcription Factor 3 on TAp73 Stability and Apoptosis in Paclitaxel-Treated Cervical Cancer Cells
Authors: Oh Yeo Kyoung , Lee Hyun Jung , Jeong Mi-Hee , Rhee Marie , Mo Ji-Won , Song Eun Hyeon , Lim Joong-Yeon , Choi Kyung-Hee , Jo Inho , Park Sang Ick , Gao Bin , Kwon Yongil , Kim Won-Ho
Published: July 2008

Taxol (paclitaxel) is a potent anticancer drug that has been found to be effective against several tumor types, including cervical cancer. However, the exact mechanism underlying the antitumor effects of paclitaxel is poorly understood. Here, paclitaxel induced the apoptosis of cervical cancer HeLa cells and correlated with the enhanced activation of caspase-3 and TAp73, which was strongly inhibited by TAp73β small interfering RNA (siRNA). In wild-type activating transcription factor 3 (ATF3)–overexpressed cells, paclitaxel enhanced apoptosis through increased α and β isoform expression of TAp73; however, these events were attenuated in cells containing inactive COOH-terminal–deleted ATF3 [ATF3(ΔC)] or ATF3 siRNA. In contrast, paclitaxel-induced ATF3 expression did not change in TAp73β-overexpressed or TAp73β siRNA–cotransfected cells. Furthermore, paclitaxel-induced ATF3 translocated into the nucleus where TAp73β is expressed, but not in ATF3(ΔC) or TAp73β siRNA–transfected cells. As confirmed by the GST pull-down assay, ATF3 bound to the DNA-binding domain of p73, resulting in the activation of p21 or Bax transcription, a downstream target of p73. Overexpression of ATF3 prolonged the half-life of TAp73β by inhibiting its ubiquitination and thereby enhancing its transactivation and proapoptotic activities. Additionally, ATF3 induced by paclitaxel potentiated the stability of TAp73β, not its transcriptional level. Chromatin immunoprecipitation analyses show that TAp73β and ATF3 are recruited directly to the p21 and Bax promoter. Collectively, these results reveal that overexpression of ATF3 potentiates paclitaxel-induced apoptosis of HeLa cells, at least in part, by enhancing TAp73β's stability and its transcriptional activity. The investigation shows that ATF3 may function as a tumor-inhibiting factor through direct regulatory effects on TAp73β, suggesting a functional link between ATF3 and TAp73β. (Mol Cancer Res 2008;6(7):1232–49)
Oncogenic Ras and Transforming Growth Factor-β Synergistically Regulate AU-Rich Element–Containing mRNAs during Epithelial to Mesenchymal Transition
Authors: Kanies Cindy L. , Smith J. Joshua , Kis Christian , Schmidt Carl , Levy Shawn , Khabar Khalid S.A. , Morrow Jason , Deane Natasha , Dixon Dan A. , Beauchamp R. Daniel
Published: July 2008

Colon cancer progression is characterized by activating mutations in Ras and by the emergence of the tumor-promoting effects of transforming growth factor-β (TGF-β) signaling. Ras-inducible rat intestinal epithelial cells (RIE:iRas) undergo a well-described epithelial to mesenchymal transition and invasive phenotype in response to H-RasV12 expression and TGF-β treatment, modeling tumor progression. We characterized global gene expression profiles accompanying Ras-induced and TGF-β–induced epithelial to mesenchymal transition in RIE:iRas cells by microarray analysis and found that the regulation of gene expression by the combined activation of Ras and TGF-β signaling was associated with enrichment of a class of mRNAs containing 3′ AU-rich element (ARE) motifs known to regulate mRNA stability. Regulation of ARE-containing mRNA transcripts was validated at the mRNA level, including genes important for tumor progression. Ras and TGF-β synergistically increased the expression and mRNA stability of vascular endothelial growth factor (VEGF), a key regulator of tumor angiogenesis, in both RIE:iRas cells and an independent cell culture model (young adult mouse colonocyte). Expression profiling of human colorectal cancers (CRC) further revealed that many of these genes, including VEGF and PAI-1, were differentially expressed in stage IV human colon adenocarcinomas compared with adenomas. Furthermore, genes differentially expressed in CRC are also significantly enriched with ARE-containing transcripts. These studies show that oncogenic Ras and TGF-β synergistically regulate genes containing AREs in cultured rodent intestinal epithelial cells and suggest that posttranscriptional regulation of gene expression is an important mechanism involved in cellular transformation and CRC tumor progression. (Mol Cancer Res 2008;6(7):1124–36)
Aldehyde Dehydrogenase Discriminates the CD133 Liver Cancer Stem Cell Populations
Authors: Ma Stephanie , Chan Kwok Wah , Lee Terence Kin-Wah , Tang Kwan Ho , Wo Jana Yim-Hung , Zheng Bo-Jian , Guan Xin-Yuan
Published: July 2008

Recent efforts in our study of cancer stem cells (CSC) in hepatocellular carcinoma (HCC) have led to the identification of CD133 as a prominent HCC CSC marker. Findings were based on experiments done on cell lines and xenograft tumors where expression of CD133 was detected at levels as high as 65%. Based on the CSC theory, CSCs are believed to represent only a minority number of the tumor mass. This is indicative that our previously characterized CD133+ HCC CSC population is still heterogeneous, consisting of perhaps subsets of cells with differing tumorigenic potential. We hypothesized that it is possible to further enrich the CSC population by means of additional differentially expressed markers. Using a two-dimensional PAGE approach, we compared protein profiles between CD133+ and CD133− subpopulations isolated from Huh7 and PLC8024 and identified aldehyde dehydrogenase 1A1 as one of the proteins that are preferentially expressed in the CD133+ subfraction. Analysis of the expression of several different ALDH isoforms and ALDH enzymatic activity in liver cell lines found ALDH to be positively correlated with CD133 expression. Dual-color flow cytometry analysis found the majority of ALDH+ to be CD133+, yet not all CD133+ HCC cells were ALDH+. Subsequent studies on purified subpopulations found CD133+ALDH+ cells to be significantly more tumorigenic than their CD133−ALDH+ or CD133−ALDH− counterparts, both in vitro and in vivo. These data, combined with those from our previous work, reveal the existence of a hierarchical organization in HCC bearing tumorigenic potential in the order of CD133+ALDH+ > CD133+ALDH− > CD133−ALDH−. ALDH, expressed along CD133, can more specifically characterize the tumorigenic liver CSC population. (Mol Cancer Res 2008;6(7):1146–53)
Psychophysiological Indicators of Stress Reactivity in Adolescent Psychiatric Patients with Dissociative Symptomatology
Authors: Brunner Romuald , Müller Carsten , Parzer Peter , Resch Franz
Published: July 2008

Background: Thus far, possible neurobiological underpinnings of dissociative symptomatology have not been studied sufficiently. We studied the reactivity of the autonomous nervous system to a non-specific laboratory stressor in a clinical group of adolescents with dissociative symptomatology. Sampling and Methods: The effects of an attentional task, administered with and without noise, on heart rate, skin resistance and the level of subjective distress were studied in 2 groups of 19 and 20 adolescent psychiatric patients with high and low degrees of self-reported dissociative symptoms as measured by the Adolescent Dissociative Experiences Scale, respectively. Results: Patients with a high degree of dissociative symptoms demonstrated significantly larger changes in heart rate during the attentional task, while the noise had no effect on heart rate. Additional noise led to an increase in skin resistance levels and subjective distress in both groups. Conclusions: The results of the current study provide preliminary evidence that the intensity of the stress response represents a sensitivity to stress which may correlate with the exacerbation and fluctuation of dissociative symptomatology.
Time until Institutionalization in Incident Dementia Cases – Results of the Leipzig Longitudinal Study of the Aged (LEILA 75+)
Authors: Luck Tobias , Luppa Melanie , Weber Stephan , Matschinger Herbert , Glaesmer Heide , König Hans-Helmut , Angermeyer Matthias C. , Riedel-Heller Steffi G.
Published: July 2008

Background: Information on the time until institutionalization and its predictors in demented subjects has so far been based on studies with selected samples or prevalent dementia cases. Thus, the aim of the study is to analyze the time until institutionalization and associated patient-related factors in incident dementia cases. Methods: Data were derived from the Leipzig Longitudinal Study of the Aged (LEILA 75+), a population-based study of individuals aged 75 years and older. Kaplan-Meier survival analysis was used to determine the time until institutionalization. Factors associated with time until institutionalization were analyzed using Cox proportional hazards models. Results: One hundred and nine subjects with incident dementia who resided in a private home setting at the time of the dementia diagnosis were identified. Fifty-two (47.7%) of these subjects had become residents of a nursing home by the end of the study. The median time until institutionalization was 1,005 days (95% CI = 808–1,202). Being widowed/divorced (compared to being married) was associated with a significantly shorter time until institutionalization (univariate model: HR = 4.50, 95% CI = 1.09–18.57). Conclusion: Being without a spouse seems to be an important factor for a shorter time until institutionalization in incident dementia cases. Tailored interventions for these subjects at risk are required.
Structure, Strain and Function of the Transverse Acetabular Ligament
Authors: Löhe F. , Eckstein F. , Sauer T. , Putz R.
Published: July 2008

To assess the morphology and function of the transverse acetabular ligament (TAL), its internal structure and insertion sites were analyzed, and its strain was determined during hip joint loading. Fifteen specimens were embedded in methyl methacrylate and cut into 500-µm sections parallel to the inlet of the acetabulum. Polarized light microscopy and contact radiography revealed important differences between the ventral and dorsal attachment of the TAL. Ventrally, the fibers insert close to the labrum, at a rather extensive site consisting of fibrous cartilage. Dorsally, the ligament arises from a wide attachment at the bony region of the posterior horn, where it is continuous with the periosteum and the joint capsule. In a second part of the study, six specimens (four fixed, two fresh) were investigated, using a testing machine to simulate hip joint loading. The strains of the TAL and of two sites of the acetabular labrum were measured with strain gauges. Loads of 10-2,800 N were applied and the degree of rotation of the femoral head was varied. At 400% body weight, the TAL encountered tensile strains of up to 3.7%, but the labrum only of up to 0.5%. The contact areas of the hip joints were determined with a polyether casting material. At 50% body weight they were found to lie in the anterior and posterior aspects of the lunate surface. These results indicate that, due to a natural incongruity, the acetabular notch is widened during loading and the TAL submitted to tension.
Learning Relational Anatomy by Correlating Thin Plastinated Sections and Magnetic Resonance Images: Preparation of Specimens
Authors: Magiros M. , Kekic M. , Doran G.A.
Published: July 2008

Plastination is a process whereby the tissue water and part of the tissue fat of anatomical specimens is replaced with a curable polymer. Several variations of this technique are available, depending on both the type of specimen and polymer being used. In this study, the efficiency of BIODUR® PEM 11-prepared cross sections as a teaching aid for radiographic anatomy is investigated. A human cadaveric head was scanned on a magnetic resonance (MR) imager, recording images in a coronal plane of ∼6 mm in thickness. Corresponding slices were then taken of this head and plastinated by the BIODUR PEM 11 method. In general, a good correlation existed between the plastinated sections and the MR scans. The plastinated slices displayed superior differentiation between musculature compared to the scans. In conclusion, the plastinated sections, used in conjunction with the MR scans, are a valuable tool in learning radiographic anatomy. Additionally, BIODUR PEM 11 is a viable alternative to plastination by other methods.
Seasonal Variation of Cloud Systems over ARM SGP
Authors: Wu Xiaoqing , Park Sunwook , Min Qilong
Published: July 2008

Increased observational analyses provide a unique opportunity to perform years-long cloud-resolving model (CRM) simulations and generate long-term cloud properties that are very much in demand for improving the representation of clouds in general circulation models (GCMs). A year 2000 CRM simulation is presented here using the variationally constrained mesoscale analysis and surface measurements. The year-long (3 January–31 December 2000) CRM surface precipitation is highly correlated with the Atmospheric Radiation Measurement (ARM) observations with a correlation coefficient of 0.97. The large-scale forcing is the dominant factor responsible for producing the precipitation in summer, spring, and fall, but the surface heat fluxes play a more important role during winter when the forcing is weak. The CRM-simulated year-long cloud liquid water path and cloud (liquid and ice) optical depth are also in good agreement (correlation coefficients of 0.73 and 0.64, respectively) with the ARM retrievals over the Southern Great Plains (SGP). The simulated cloud systems have 50% more ice water than liquid water in the annual mean. The vertical distributions of ice and liquid water have a single peak during spring (March–May) and summer (June–August), but a second peak occurs near the surface during winter (December–February) and fall (September–November). The impacts of seasonally varied cloud water are very much reflected in the cloud radiative forcing at the top-of-atmosphere (TOA) and the surface, as well as in the vertical profiles of radiative heating rates. The cloudy-sky total (shortwave and longwave) radiative heating profile shows a dipole pattern (cooling above and warming below) during spring and summer, while a second peak of cloud radiative cooling appears near the surface during winter and fall.
Tropical Cyclone Energy Dispersion in a Three-Dimensional Primitive Equation Model: Upper-Tropospheric Influence*
Authors: Ge Xuyang , Li Tim , Wang Yuqing , Peng Melinda S.
Published: July 2008

The three-dimensional (3D) Rossby wave energy dispersion of a tropical cyclone (TC) is studied using a baroclinic primitive equation model. The model is initialized with a symmetric vortex on a beta plane in an environment at rest. The vortex intensifies while becoming asymmetric and moving northwestward because of the beta effect. A synoptic-scale wave train forms in its wake a few days later. The energy-dispersion-induced Rossby wave train has a noticeable baroclinic structure with alternating cyclonic–anticyclonic–cyclonic (anticyclonic–cyclonic–anticyclonic) circulations in the lower (upper) troposphere.

A key feature associated with the 3D wave train development is a downward propagation of the relative vorticity and kinetic energy. Because of the vertical differential inertial stability, the upper-level wave train develops faster than the lower-level counterpart. The upper anticyclonic circulation rapidly induces an intense asymmetric outflow jet in the southeast quadrant, and then further influences the lower-level Rossby wave train. On one hand, the outflow jet exerts an indirect effect on the lower-level wave train strength through changing TC intensity and structure. On the other hand, it triggers downward energy propagation that further enhances the lower-level Rossby wave train. A sudden removal of the diabatic heating may initially accelerate the energy dispersion through the increase of the radius of maximum wind and the reduction of the lower-level inflow. The latter may modulate the group velocity of the Rossby wave train through the Doppler shift effect. The 3D numerical results illustrate more complicated Rossby wave energy dispersion characteristics than 2D barotropic dynamics.
Investigation of Droplet Size Distributions and Drizzle Formation Using a New Trajectory Ensemble Model. Part I: Model Description and First Results in a Nonmixing Limit
Authors: Pinsky M. , Magaritz L. , Khain A. , Krasnov O. , Sterkin A.
Published: July 2008

A novel trajectory ensemble model of a stratocumulus cloud is described. In this model, the boundary layer (BL) is fully covered by a great number of Lagrangian air parcels that during their motion can contain either wet aerosols or aerosols and droplets. The diffusion growth of aerosols and droplets, as well as drop collisions, is accurately described in each parcel. Droplet sedimentation is taken into account, which allows simulation of precipitation formation. The Lagrangian parcels are advected by the velocity field generated by the turbulent-like flow model obeying turbulent correlation laws. The output of the numerical model includes droplet and aerosol size distributions and their moments, such as droplet concentration, droplet spectrum width, cloud water content, drizzle content, radar reflectivity, etc., calculated in each parcel. Horizontally averaged values are calculated as well.

Stratocumulus clouds observed during two research flights (RF01 and RF07) in the Second Dynamics and Chemistry of Marine Stratocumulus (DYCOMS II) field campaign are simulated. A good agreement between the dynamical and microphysical structures simulated by the model with observations is obtained even in the nonmixing limit. A crucial role of sedimentation for the creation of a realistic cloud microphysical structure is demonstrated. In sensitivity studies, the statistical stability of the model is analyzed.

Applications of the model for the investigation of droplet size distribution and drizzle formation are discussed, as is the possible utilization of the model for remote sensing applications.
The Tropospheric Jet Response to Prescribed Zonal Forcing in an Idealized Atmospheric Model
Authors: Chen Gang , Zurita-Gotor Pablo
Published: July 2008

This paper explores the tropospheric jet shift to a prescribed zonal torque in an idealized dry atmospheric model with high stratospheric resolution. The jet moves in opposite directions for torques on the jet’s equatorward and poleward flanks in the troposphere. This can be explained by considering how the critical latitudes for wave activity absorption change, where the eastward propagation speed of eddies equals the background zonal mean zonal wind. While the increased zonal winds in the subtropics allow the midlatitude eddies to propagate farther into the tropics and result in the equatorward shift in the critical latitudes, the increased winds in the midlatitudes accelerate the eastward eddy phase speeds and lead to the poleward shift in the critical latitudes.

In contrast, the jet moves poleward when a westerly torque is placed in the extratropical stratosphere irrespective of the forcing latitude. The downward penetration of zonal winds to the troposphere displays a poleward slope for the subtropical torque, an equatorward slope for the high-latitude torque, and less tilting for the midlatitude torques. The stratospheric eddies play a key role in transferring zonal wind anomalies downward into the troposphere. It is argued that these stratospheric zonal wind anomalies can affect the tropospheric jet by altering the eastward propagation of tropospheric eddies. Additionally, the zonal wind response to a subtropical zonal torque in this idealized model is of value in understanding the tropospheric jet sensitivity to the orographic gravity wave drag parameterization in a realistic climate model.
Meridional and Downward Propagation of Atmospheric Circulation Anomalies. Part II: Southern Hemisphere Cold Season Variability
Authors: Ren R-C. , Cai Ming
Published: July 2008

As in the Northern Hemisphere, there exists a simultaneous poleward propagation of temperature anomalies in the stratosphere and equatorward propagation in the troposphere in the Southern Hemisphere’s cold season. It takes about 110 days for anomalies of one polarity to propagate from the equator to the pole (or half the period of the complete cycle), nearly twice as long as in the Northern Hemisphere. The earlier poleward propagation of temperature anomalies in upper levels compared with those in lower levels results in an apparent downward propagation in the stratosphere. Accompanying the poleward- and downward-propagating warm (cold) anomalies is a successive leveling (steepening) of isentropic surfaces, reflecting a simultaneous reduction (strengthening) of the meridional temperature gradient and increase (decrease) of the vertical static stability. Following changes in the thermal fields are poleward- and downward-propagating zonal wind anomalies of the opposite sign.

The arrival of the poleward-propagating stratospheric thermal anomalies over the polar region coincides with the beginning of the compensating equatorward advancement of tropospheric thermal anomalies of the opposite sign. The synchronized meridional propagation in the thermal fields results from the temporal variation between stronger and weaker meridional mass circulations, which is responsible for a meridional out-of-phase variability pattern in both the stratosphere and troposphere and a vertical out-of-phase pattern between stratospheric and tropospheric temperature anomalies at high latitudes. The vertical alignment of a warm high (cold low) anomaly in the stratosphere overlying a cold high (warm low) anomaly at the surface explains the apparent “equivalent barotropic” structure in the height anomalies.
Midportion Achilles Tendon Microcirculation after Intermittent Combined Cryotherapy and Compression Compared with Cryotherapy Alone
Authors: Knobloch Karsten , Grasemann Ruth , Spies Marcus , Vogt Peter M.
Published: July 2008

Background

The effect of combined cryotherapy/compression versus cryotherapy alone on the Achilles tendon is undetermined.

Hypothesis

Standardized combined cryotherapy/compression changes in midportion Achilles tendon microcirculation are superior to those with cryotherapy during intermittent application.

Study Design

Controlled laboratory study.

Methods

Sixty volunteers were randomized for either combined cryotherapy/compression (Cryo/Cuff, DJO Inc, Vista, California: n = 30; 32 ± 11 years) or cryotherapy alone (KoldBlue, TLP Industries, Kent, United Kingdom: n = 30; 33 ± 12 years) with intermittent 3 × 10-minute application. Midportion Achilles tendon microcirculation was determined (02C, LEA Medizintechnik, Giessen, Germany).

Results

Both Cryo/Cuff and KoldBlue significantly reduced superficial and deep capillary tendon blood flow within the first minute of application (43 ± 46 arbitrary units [AU] vs 10 ± 19 AU and 42 ± 46 AU vs 12 ± 10 AU; P = .0001) without a significant difference throughout all 3 applications. However, during recovery, superficial and deep capillary blood flow was reestablished significantly faster using Cryo/Cuff ( P = .023). Tendon oxygen saturation was reduced in both groups significantly (3 minutes Cryo/Cuff: 36% ± 20% vs 16% ± 15%; KoldBlue: 42% ± 19% vs 28% ± 20%; P < .05) with significantly stronger effects using Cryo/Cuff ( P = .014). Cryo/Cuff led to significantly higher tendon oxygenation (Cryo/Cuff: 62% ± 28% vs baseline 36% ± 20%; P = .0001) in superficial and deep tissue (Cryo/Cuff: 73% ± 14% vs baseline 65% ± 17%; P = .0001) compared with KoldBlue during all recoveries. Postcapillary venous filling pressures were significantly reduced in both groups during application; however, Cryo/Cuff led to significantly, but marginally, lower pressures (Cryo/Cuff: 41 ± 7 AU vs baseline 51 ± 13 AU; P = .0001 and KoldBlue: 46 ± 7 AU vs baseline 56 ± 11 AU; P = .026 for Cryo/Cuff vs KoldBlue).

Conclusion

Increased tendon oxygenation is achieved as tendon preconditioning by combined cryotherapy and compression with significantly increased tendon oxygen saturation during recovery in contrast to cryotherapy alone. Both regimens lead to a significant amelioration of tendinous venous outflow.

Clinical Relevance

Combined cryotherapy and compression is superior to cryotherapy alone regarding the Achilles tendon microcirculation. Further studies in tendinopathy and tendon rehabilitation are warranted to elucidate its value regarding functional issues.
Hip Injuries and Labral Tears in the National Football League
Authors: Feeley Brian T. , Powell John W. , Muller Mark S. , Barnes Ronnie P. , Warren Russell F. , Kelly Bryan T.
Published: July 2008

Background

Injuries to the hip account for approximately 10% of all injuries in football, but definitive diagnosis is often challenging. Although these injuries are often uncomplicated contusions or strains, intra-articular lesions are increasingly found to be sources of hip pain.

Purpose

The objective was to define the incidence and etiologic factors of intra- and extra-articular hip injuries in the National Football League (NFL).

Study Design

Descriptive epidemiology study.

Methods

The NFL Injury Surveillance System was used to define all hip-related injuries from 1997 to 2006. Injuries were included if the athlete missed more than 2 days. All hip and groin injuries were included for evaluation. The authors also report on NFL players with intra-articular injuries seen at their institution outside of the NFL Injury Surveillance System.

Results

There were a total of 23 806 injuries from 1997 to 2006, of which 738 were hip injuries (3.1 %) with an average of 12.3 days lost per injury. Muscle strains were the most common injury. Intra-articular injuries resulted in the most time lost. Contact injuries most likely resulted in a contusion, and noncontact injuries most often resulted in a muscle strain. In the authors’ institutional experience, many of the athletes with labral tears have persistent adductor strains that do not improve despite adequate therapy.

Conclusion

Hip injuries represent a small but substantial percentage of injuries that occur in the NFL. A majority of these injuries are minor, with a return to play within 2 weeks. Intra-articular injuries are more serious and result in a significant loss of playing time. The “sports hip triad” (labral tear, adductor strain, and rectus strain) is described as a common injury pattern in the elite athlete.
Effect of T-Joint Geometry on the Performance of a GRP/PVC Sandwich System Subjected to Tension
Authors: Diler Ege Anil , Özes Çiçek , Neşer Gökdeniz
Published: July 2008

Mechanical performances of six sandwich type T-joints, used in marine applications subjected to tensile load, have been investigated both numerically and experimentally in this study T-joints, each with different geometries, have been manufactured, Type A: continuous core in join with right angle; Type B: core removed at joint; Type C: core with wedge fillet; Type D: core with 25 mm radius fillet; Type E: core with 70 mm radius fillet and Type F: DK-CND1 of Toftegaard and Lystrup with overlaminate. The skin was a 5mm thick orthophitalic polyester/glass laminated composite and the core was PVC (Divinycell H80). Due to absolute values of the maximum strain values of the T-joints, Type E shows promising performance under tension while Type B is the weakest. It is not recommended to use Type B in the structures subjected to tension. Grading from the strongest to the weakest of T-joints is Type C, D, A and F. Results of the numerical modelling and tests also affirm the utility of the 2D FE models for further studies of the strain distribution in such sandwich T-joints.
A Review on Carbon Epoxy Nanocomposites
Authors: Rana Sohel , Alagirusamy R. , Joshi Mangala
Published: July 2008

Carbon nanotubes are the major component of nanotechnology and a considerable area of research, due to their outstanding physical and mechanical properties. Since their discovery in 1991, extensive research has been carried out to understand and exploit these unique properties in the form of composites for various applications. But the main challenge lies in transferring the properties of carbon nanotubes to the nanocomposites successfully. In this paper, recent research in the field of carbon nanotubes reinforced epoxy composites and carbon epoxy three phase composites are reviewed.
Dynamic Instability of Imperfect Sandwich Laminates by an Efficient FE Model
Authors: Chakrabarti Anupam
Published: July 2008

In this paper the dynamic instability of sandwich laminates having inter-laminar imperfection is studied for the first time. An efficient finite element model recently developed by the authors is used for the purpose. The plate model is based on a refined higher order shear deformation theory, where the transverse shear stresses are continuous at the layer interfaces with stress free conditions at plate top and bottom. A linear spring-layer model is used to model the interlaminar imperfection by introducing in-plane displacement jump at different interfaces. It is interesting to note that the plate model having all these refined features requires unknowns at the reference plane only.