bluuebunny/crossref_metadata_2025 huggingface dataset:
Flecainide blocks the stimulatory effect of veratridine on slowly adapting pulmonary stretch receptors in anaesthetized rabbits without changing lung mechanics
Authors: MATSUMOTO S. , SHIMIZU T.
Published: December 2008

We examined the responses of slowly adapting pulmonary stretch receptors (PSRs), total lung resistance (RL) and dynamic lung compliance (Cdyn) to administered veratridine before and after pretreatment with atropine or flecainide in anaesthetized, artificially ventilated rabbits with bilateral vagotomy. Administration of veratridine (10 and 30 μg kg‐1) caused vigorous stimulation of PSRs, resulting in a tonic discharge of receptors during both inflation and deflation, but did not significantly alter either RLor Cdyn. The veratridine‐induced PSR stimulation became more prominent, as the dose of this alkaloid was increased. Pretreatment with atropine (1 or 2 mg kg‐1) had no significant effect on the excitatory response of PSRs to veratridine. The veratridine induced PSR stimulation was inhibited by treatment with flecainide (1, 2 and 3 mg kg‐1), a sodium channel blocker, and this inhibition was dose‐dependent. These results suggest that activation of PSRs following veratridine administration probably related to the increased influx of sodium ions into the receptive terminals but does not depend upon bronchoconstriction.
Lymphocyte redistribution in connection with physical activity in the rat
Authors: ESPERSEN G. T. , STAMP I. , JENSEN M. LIDANG , ELBÆK A. , ERNST E. , KAHR O. , GRUNNET N.
Published: December 2008

Previous studies have demonstrated numerous immunobiological changes in conection with exercise. A decrease in peripheral blood mononuclear white cells (PBMC) 2 h after intense exercise has been shown. This lymphocytopenia in humans after exercise is thought to be of great importance regarding the morbidity to viral infection. We constructed an animal experimental set‐up, previously published, to investigate the exercise‐induced lymphocyte redistribution. The experimental set‐up allowed us to draw blood from catheters implanted in the right carotid artery in rats. PBMC were isolated and labelled with Ins111 and reinfused before the exercise run on a treadmill to exhaustion. The runner and control rats were killed and dissection performed 1 h after the exercise. Tissue samples were weighed and measured in a gamma counter. Furthermore, blind microscopic examinations of selected tissues were performed to study a hypothesized accumulation of blood mononuclear cells in relation to muscle fibre lesions. We found that the total number of PBMC in the running rats was decreased (P = 0.018) and granulocytes increased, 1 h after the exercise (P = 0.028). Similar findings in humans in connection with physical activity have been observed. The percentage of total injected counts per minute per gram tissue (% c.p.m. g‐1) showed significantly lower values in the liver and kidney from runners than from controls (P = 0.032 and P = 0.028). These findings might be the result of a visceral hypoflowin connection with exercise. Furthermore, a tendency to decreased % c.p.m. g‐1 in the lungs was seen in the exercised rats (P = 0.083) indicating a possible redistribution from the lungs during the run. Light microscopy demonstrated an accumulation of PBMC around muscle fibre lesions, but there was no significant difference between runners and controls. Furthermore, no significant difference in % c.p.m: g‐1 was found between working muscle groups in runner and control rats. In conclusion, the demonstration of the redistribution of PBMC from the liver and kidney in the exercised rats and the absence of any significant accumulation of PBMC in working muscles or other organs, do not explain the lymphocytopenia demonstrated here.
Contraction specific changes in passive torque in human skeletal muscle
Authors: MAGNUSSON S. P. , SIMONSEN E. B. , AAGAARD P. , MORITZ U. , KJAER M.
Published: December 2008

The present investigation examined passive torque and electromyographic response in human skeletal muscle during passive static stretch within 60 s after maximal repetive eccentric and concentric contractions. Passive torque (Nm) offered by the hamstring muscle group was measured during passive knee extension in a modified dynamometer in 10 subjects. The distal thigh was elevated to 0.52 rad from horizontal and the backrest was positioned at 1.57 rad. The lever arm moved the leg passivelly at 0.09 rad s‐1from a starting positioned of 1.48 rad below horizontal to the final position where it remained stationary for 90s. Gross electrical activity of the human hamstring muscle group was recorded simultaneously. The effect of concentric or eccentric contraction was tested on separate days. Two stretch manoeuvres with a 45 min hiatus were administered on a control and experimental side. The experimental side performed 40 maximal effort repetitive concentric or eccentric hamstring muscle contractions at 1.05 rad s‐1prior to the second stretch. Passive torque during the 90s stretch declined 30–35% on the experimental and control side in all stretches. P<0.001 without a significant effect of prior contraction mode. Passive peak and final torques were lower on the experimental side, P<0.01 after concentric contractions. Passive peak and final torques remained unchanged after eccentric contractions on the experimental side. The low level EMG response of the hamstring muscle during the stretch was unchanged after maximal repetitive concentric or eccentric contractions. These data demonstrate acute contraction specific alteration in passive torque in human skeletal muscle, which cannot be accounted for by EMG activity. Furthermore, the lack of difference on the control side implies that one 90s stretch has no effect on passive torque of the muscle 45 min later.
Regional myosin heavy chain expression in volume and pressure overload induced cardiac hypertrophy
Authors: DOOL J.S. , MAK A.S. , FRIBERG P. , WAHLANDER H. , HAWRYLECHKO A. , ADAMS M.A.
Published: December 2008

Although the overall shift towards the V3, myosin heavy chain (MHC) has been shown to be associated with cardiac hypertrophy, quantitative evidence describing regional expression is sparse. The aim of this study was to compare and contrast the regional ventricular myosin isoform expression in two distinct haemodynamic states:pressure and volume overload. Volume overload was achieved using an aortocaval fistula (ACF) model and pressure overload by two‐kidney‐one‐clip (2KlC) hypertension. A separate group (UC‐2KlC) had the clip removed 1 week prior to investigation. Sham operated rats (SHAM) served as controls. All groups were studied 4 weeks after surgery. Ventricular tissue samples (≅ 50 mg) were taken from the walls of the right ventricle (RV), septum and left ventricular (LV) free wall. Tissue samples (excluding RV) were divided into endocardium and epicardium, and myosin expression was determined using polyacrylamide gel electrophoresis. Cardiac hypertrophy was substantial in both LV (1.7‐fold) and RV (1.9‐fold) in ACF rats. The 2K1C rats had similar LV enlargement (1.6‐fold) whereas RV hypertrophy was not as great (1.2‐fold). Blood pressure (BP) was increased 65% in 2K1C rats, whereas there was no change in ACF rats with respect to SHAM animals. After unclipping (UC‐2KIC), LV hypertrophy and BP had returned towards control levels. In general, V3, MHC expression was associated with increasing LV hypertrophy in both 2K1C and ACF models. However, there was a marked endo‐epi differential (1.5: 1) in the LV free wall and septum of 2K1C rats. In contrast, in ACF rats there was no differential V3, MHC expression in the LV or septa1 tissue, i. e. expression was similar in both endo‐and epi‐samples. Elevated expression of V3, MHC persisted despite normotension and regression of cardiac hypertrophy in UC‐2K1C rats. Taken together with published results demonstrating that relative transmural myocyte hypertrophy in ACF rats (endo < epi) is in contrast to that seen in 2K1C rats (epi > endo), the present findings reveal that regional V3, myosin expression represents a distinct adaptational component of the overall cardiac hypertrophic response in both volume and pressure overload.
Endothelin‐induced contractions in human placental blood vessels are enhanced in intrauterine growth retardation, and modulated by agents that regulate levels of intracellular calcium.
Authors: LIU Y.‐A. , ÖSTLUND E. , FRIED G.
Published: December 2008

Endothelin‐1 (ET‐1) is a strongly vasoactive polypeptide that may be involved in the regulation of the uteroplacental blood flow. In the present study we have examined the contractile response to ET‐1 in human placental arteries in the presence of several agents that interfere with storage of intracellular calcium, e. g. caffeine, ryanodine and thapsigargin. We have also compared the contractile response to ET‐1 in normal pregnancies with that of patients with foetal intrauterine growth retardation (IUGR), a condition with reduced uteroplacental blood flow. We found that the response to ET‐1 in the placental arteries from women with normal pregnancies was reduced by 20% in the absence of extracellular calcium. Caffeine relaxed the basal tone of the vessels and reduced the contractile response to ET‐1 by 51 %. Nifedipine in addition to caffeine resulted in a reduction of 700/,.Ryanodine also reduced the tone. Thapsigargin had no effect on the placental arteries at lower concentrations, but gave a progressive and slow contraction at 10‐6M. The ET‐1 induced contraction in placental arteries from IUGR patients was 67% more potent than in placental arteries from women with normal pregnancies, 129% as compared with 77% of the maximal K+induced contraction. We conclude that the ET‐1‐induced contractile response in the human placental artery is dependent on influx of extracellular calcium as well as mobilization of calcium from intracellular stores. An increased sensitivity to ET‐1 in placental arteries may contribute to the reduced uteroplacental blood flow in intrauterine growth retardation.
The bovine central adrenomedullary vein: a target for endothelins
Authors: LØNNING K. , HELLE K. B.
Published: December 2008

This study reports on morphological and contractile properties of the bovine central adrenomedullary vein (bCAMV). Up to several layers of circularly orientated smooth muscle cells (SMC) were observed, however, without forming a continuous, closed sheath. Discrete bundles of eccentrically arranged, longitudinal SMC were also conspicuous. Chromaffin cells were in most cases located outside the SMC layers, while sometimes being in close apposition to the endothelium in areas without SMC. Circularly mounted preparations of the endothelium‐denuded vessel responded selectively to high K+, endothelins (ETs) and neuropeptide Y (NPY). The threshold for ET‐1 was 0.13 nm and the half maximally effective concentration (EC50) was 3pL1 nm (n= 9). The order of potencies was ET‐1 ≥ ET‐2 ≥ ET‐3, suggesting a vascular receptor (ETA). Concentrations at and above EC50 frequently developed long‐lasting oscillations during the spontaneous relaxation of the ET‐1 evoked tension. This response was partly (21%) independent of extracellular Ca2+. A marked tachyphylaxis developed to ET‐1 (3–30 nm), resulting, on the other hand, in facilitation of the subsequent constrictor responses to high K+ and NPY. Propranolol and phentolamine alone, or in combination, were without effects on the basal tension and on the above‐mentioned responses to high K+, ET‐1 or NPY, making a contribution from adrenoceptor activation unlikely. No response was obtained with exogenous cate‐cholamines, acetylcholine or serotonin, nor with a series of peptides known to occur in the adrenal medulla. This study shows that bCAMV is not a passive capacitance vessel but appears unique among mammalian veins in being selectively regulated by ETs.
Sympathetic influence on cardiovascular responses to sustained head‐up tilt in humans
Authors: PEDERSEN M. , MADSEN P. , KLOKKER M. , OLESEN H. L. , SECHER N. H.
Published: December 2008

Sympathetic β‐adrenergic influences on cardiovascular responses to 50d̀ head‐up tilt were evaluated with metoprolol (β1‐blockade; 0.29 mg kg‐1) and propranolol (β1and β‐2‐blockade; 0.28 mg kg‐1) in eight males. A normotensive‐tachycardic phase was followed by a hypotensive‐bradycardic episode associated with presyncopal symptoms after 23pL3 min (control, mean pLSE). Head‐up tilt made thoracic electrical impedance (3.0pL10Ω), mean arterial pressure (MAP, 86pL4‐93pL4 mmHg), heart rate (HR, 63pL3‐99pL10 beats min‐1) and total peripheral resistance (TPR, 15pL1‐28pL4 mmHg min L‐1) increase, while central venous oxygen saturation (74pL2‐58pL4%), cardiac output (5.7pL0.1–3.1pL0.3 L min‐1), stroke volume (95pL6‐41pL5 mL) and pulse pressure (55pL4‐49pL4 mmHg) decreased (P< 0.05). Central venous pressure decreased during head‐up tilt (7pL2‐0pL1 mmHg), but it remained stable during the sustained tilt. At the appearance of preswyncopal symptoms MAP (49pL3 mmHg), HR (66pL4 beats min‐1) and TPR (15pL3 mmHg min L‐1) decreased (P< 0.05). Neither metoprolol or propranolo changed tilt tolerance or cardiovascular variables, except for HR that remained at 57pL2 (metoprolol) and 55pL3 beats min‐1(propranolol), and MAP that remained at 87pL5 mmHg during the first phase with metoprolol. In conclusion, sympathetic activation was crucial for the heart rate elevation during normotensive head‐up tilt, but not for tilt tolerance or for the associated hypotension and bradycardia.
Hyperglycaemia is responsible for the inhibited gastrointestinal transit in the early diabetic rat
Authors: CHANG F.‐Y. , LEE S.‐D. , YEH G.‐H. , WANG P.‐S.
Published: December 2008

The effect of plasma glucose levels on the gastrointestinal motility of the rat was studied. Chronic hyperglycaemia was induced by i. v. injection of streptozotocin 1 week before the motility experiment. Some rats received additional daily insulin therapy (1.25, 2.5 or 10 IU kg‐1) after induction of diabetes mellitus. Acute hyperglycaemia was induced by the continuous i. v. infusion of glucose solution (11, 22, 44 or 88 mg kg‐1 min‐1) 10 min before the motility experiments. The rats were killed 15 min after successful orogastric feeding of a charcoal‐contained suspension. Gastrointestinal transit was calculated as the percentage of the overall lenght of the small intestine to which the charcoal moved during this time period. The diabetic rats were found to have delayed transit compared with controls (meanpLSEM: 32.2pL2.1% vs. 42.9pL4.2%, P<0.05). Correction with moderate doses of insulin therapy failed to inhibt transit, whereas hypoglycaemia induced by high‐dose insulin treatment enhanced transit, whereas hypoglycaemia induced by high‐dose insulin treatment enhanced transit. High doses of glucose elicited acute hyperglycaemia and delayed transit when compared with saline infused non‐diabetic rats. In early diabetes, hyperglycaemia probably mediates the inhibited gastrointestinal transit, since correction of hyperglycaemia usually restores the delayed transit.
Climate change, boundary increase and elongation of a pre‐existing cline: A case study inDrosophila ananassae
Authors: RAJPUROHIT Subhash , PARKASH Ravi , SINGH Shama , RAMNIWAS Seema
Published: December 2008

During the past two to three decades,Drosophila ananassae, a warm adapted tropical species, has invaded low to mid altitude localities in the western Himalayas. Due to its cold sensitivity, this species had never been recorded from higher latitudes as well as altitudes in India to the 1960s. A latitudinal cline in this desiccation‐sensitive species corresponds with southern humid tropical localities rather than northern drier subtropical localities. An extension of its cline into lowland to midland montane localities has resulted due to global climatic change as well as local thermal effects through anthropogenic impact. However,D. ananassaepopulations at species borders are characterized by lower genetic variability for body melanization as well as for desiccation resistance. There is a lack of thermal plastic effects for body melanization, and the observed extended cline might represent evolutionary (genetic) response due to selection pressure imposed by drier habitats. A comparison of fecundity, hatchability and viability at three growth temperatures (17, 20 and 25°C) showed significant reduction in trait values at 17°C inD. ananassae. Thus, its recent range expansion into northern montane localities might involve genetic effects on stress‐related traits and plastic effects on life history traits. We suggest thatD. ananassaecould serve as an indicator species for analyzing range expansion under changing climatic conditions.
Lycorma delicatula(Hemiptera: Auchenorrhyncha: Fulgoridae: Aphaeninae) finally, but suddenly arrived in Korea
Authors: HAN Jung Min , KIM Hyojoong , LIM Eun Ji , LEE Seunghwan , KWON Yong‐Jung , CHO Soowon
Published: December 2008

A history of name changes in two fulgorid species –Lycorma delicatulaandLimois emelianovi– is reviewed.Lycorma delicatulawas once mistakenly reported to occur in Korea. Now, it has suddenly become common in western Korea, creating the suspicion that it has recently arrived from China and settled in Korea. A brief morphological and biological description ofL. delicatulais provided, and its original Korean name, “ggot‐mae‐mi”, is revalidated.Limois emelianovi, sometimes considered a synonym ofemeljanovi, is the correct name for this species, asemeljanoviis simply another transliteration of the personal name Emelianov, Emeljanov or Emel’yanov. The nameemelianovistands correct based on the International Code of Zoological Nomenclature code 32.5.1, because there is no internal evidence of an inadvertent error, and an incorrect transliteration is not considered an inadvertent error. The cytochrome oxidase I (COI) barcoding regions of both species were sequenced and compared for future reference.
Taxonomic review of the subfamily Nacerdinae (Coleoptera: Oedemeridae) in Korea
Authors: YOO In Seong , PARK Hae Chul , KIM Jin Ill
Published: December 2008

Here, we present a taxonomic review of the oedemerid subfamily Nacerdinae in Korea. Eleven species in five genera under two tribes are recognized. The subgenus Nacerdes (Patiala), represented by Nacerdes (Patiala) ocularis (Lewis), is identified for the first time in Korea. Keys, diagnoses, habitus photos of adults, and drawings of male genitalia are provided.
An extremely low frequency magnetic field increases unconditioned larval movement of the common cutworm, Spodoptera litura: A novel model for a magnetoreceptive neurobehavioral study
Authors: CHAE Kwon‐Seok
Published: December 2008

One of the most interesting features of magnetic field (MF) responsiveness in animals is the signal transduction mechanism from sensing MF to behavior. To develop a model system for understanding the process, we performed a preliminary behavioral assay using an insect, the common cutworm, Spodoptera litura (Fabricius). In contrast to sham exposure, a continuous 60 Hz oscillating MF (0.2 mT) induced a significant increase in movement in third instar larvae: the MF‐induced movement was longer in total duration and had an earlier onset than movement from sham exposure. Not surprisingly, the movement duration of the group test was notably higher than that of the individual test, suggesting that the individual test is more favorable for assessing the MF effect on movement. Considering the simplicity of the experimental operation and obvious non‐conditioned responsiveness to the MF, this model might be suitable for studying magnetoreception and following the signal transduction mechanism between neurons and behavior.
Photochemical Internalization of Bleomycin is Superior to Photodynamic Therapy Due to the Therapeutic Effect in the Tumor Periphery
Authors: Norum Ole‐Jacob , Gaustad Jon‐Vidar , Angell‐Petersen Even , Rofstad Einar K. , Peng Qian , Giercksky Karl‐Erik , Berg Kristian
Published: December 2008

Photochemical internalization (PCI) is under development for clinical use in treatment of soft tissue sarcomas and other solid tumors. PCI may release endocytosed bleomycin (BLM) into the cytosol by photochemical rupture of the endocytic vesicles. In this study, the human fibrosarcoma xenograft HT1080 was transplanted into the leg muscle of athymic mice. The photosensitizer disulfonated aluminum phthalocyanine (AlPcS2a) and BLM were systemically administrated 48 h and 30 min, respectively, prior to light exposure at 670 nm (30 J cm−2). The purposes of this study were to evaluate the treatment response to AlPcS2a‐photodynamic therapy (PDT) and AlPcS2a‐PDT in combination with BLM (i.e. PCI of BLM) in an orthotopic, invasive and clinically relevant tumor model and to explore the underlying response mechanisms caused by PDT and PCI of BLM. The treatment response was evaluated by measuring tumor growth, contrast‐enhanced magnetic resonance imaging (CE‐MRI), histology and fluorescence microscopy. The results show that PCI of BLM is superior to PDT in inducing tumor growth retardation and acts synergistically as compared to the individual treatment modalities. The CE‐MRI analyses 2 h after AlPcS2a‐PDT and PCI of BLM identified a treatment‐induced nonperfused central zone of the tumor and a well‐perfused peripheral zone. While there were no differences in the vascular response between PDT and PCI, the histological analyses showed that PDT caused necrosis in the tumor center and viable tumor cells were found in the tumor periphery. PCI caused larger necrotic areas and the regrowth in the peripheral zone was almost completely inhibited after PCI. The results indicate that PDT is less efficient in the tumor periphery than in the tumor center and that the treatment effect of PCI is superior to PDT in the tumor periphery.
Effect of Two Different UVA Doses on the Rabbit Cornea and Lens
Authors: Čejka Čestmír , Pláteník Jan , Buchal Richard , Guryca Vilém , Širc Jakub , Vejražka Martin , Crkovská Jiřina , Ardan Taras , Michálek Jiří , Brůnová Blanka , Čejková Jitka
Published: December 2008

The aim of the present paper was to examine the irradiation effect of two doses of UVA rays (365 nm) on the rabbit cornea and lens. Corneas of anesthetized adult albino rabbits were irradiated with UVA rays for 5 days (daily dose 1.01 J cm−2 in one group of rabbits and daily dose 2.02 J cm−2 in the second group of animals). The third day after the last irradiation, the rabbits were killed, and their eyes were employed for spectrophotometrical, biochemical and immunohistochemical investigations. Normal eyes served as controls. Absorption spectra of the whole corneal centers were recorded over the UV–VIS (visible) spectral range. Levels of antioxidant and prooxidant enzymes, nitric oxide synthases and nitric oxide (indirectly measured as nitrate concentration) were investigated in the cornea. Malondialdehyde, a byproduct of lipid peroxidation, was examined in the cornea and lens. The results show that the staining for endothelial nitric oxide synthase was more pronounced in corneas irradiated with the higher UVA dose. Otherwise, UVA rays at either dose did not significantly change corneal light absorption properties and did not cause statistically significant metabolic changes in the cornea or lens. In conclusion, UVA rays at the employed doses did not evoke harmful effects in the cornea or lens.
Cytoprotective Role of Mitogen‐activated Protein Kinase Phosphatase‐1 in Light‐damaged Human Retinal Pigment Epithelial Cells
Authors: Lornejad‐Schäfer Mohammad Reza , Schäfer Christine , Schöffl Harald , Frank Jürgen
Published: December 2008

The role of the mitogen‐activated protein (MAP) kinase phosphatases (MKPs) in light‐damaged cells is unclear. Therefore we investigated the involvement of MKP‐1 in the regulation of apoptosis and cell survival mediated by MAP kinase pathways in light‐damaged human retinal pigment epithelial cells (ARPE‐19). Light dose‐dependent changes in the expression of MKP‐1 and in the phosphorylation status of the MAP kinases, c‐Jun‐N‐terminal kinase (JNK) and p38 were demonstrated. Low light doses up to 2 J cm−2 led to an upregulation of MKP‐1 which resulted in the prevention of cell death by inactivating JNK kinase. However, higher light doses (≥3 J cm−2) significantly reduced MKP‐1 protein expression and subsequently led to an increased JNK kinase activity followed by a significant increase in cell death. JNK kinase inactivation by the JNK inhibitor SP600125 significantly reduced light‐induced cell death, suggesting that the cytoprotective properties of MKP‐1 are mediated mainly by the JNK MAP kinase pathway. Physiological concentrations of ascorbic acid or taurine were seen to prevent apoptosis and cell death in light‐damaged ARPE‐19 cells by reducing oxidative stress within cells, thus maintaining MKP‐1 at high levels, leading to an inactivation of the JNK kinase pathway which resulted in an increased cell viability.
Narrow‐band UVB‐induced Externalization of Selected Nuclear Antigens in Keratinocytes: Implications for Lupus Erythematosus Pathogenesis†
Authors: Reich Adam , Meurer Michael , Viehweg Antje , Muller Daniel J.
Published: December 2008

The aim of this study was to analyze whether sera obtained from patients with lupus erythematosus (LE) react with membrane structures found on keratinocytes irradiated with narrow‐band ultraviolet B (NB‐UVB). We applied atomic force microscopy (AFM) to visualize cell surface structures expressing nuclear antigens upon apoptosis following NB‐UVB irradiation. Immortalized human keratinocytes (HaCaT) were cultured under standard conditions, irradiated with 800 mJ cm−2 NB‐UVB light and imaged by AFM mounted on an inverted optical microscope. It was observed that NB‐UVB irradiation provoked significant alterations of the keratinocyte morphology and led to the membrane expression of antigens recognized by anti‐La and anti‐Ro 60 kDa sera but not by antidouble‐strand DNA sera. The presence of La and Ro 60 kDa antigens on keratinocyte surfaces after NB‐UVB irradiation was limited mainly to the small bleb‐like protrusions found on the keratinocytes by AFM. A closer investigation by AFM also revealed that some structures positively stained with anti‐Ro 60 kDa serum were also located submembranously. We hypothesize that the externalization of some nuclear antigens because of NB‐UVB exposure might be responsible for exacerbation of skin symptoms in patients suffering from LE.
Photoinduced Nitric Oxide and Singlet Oxygen Release from ZnPC Liposome Vehicle Associated with the Nitrosyl Ruthenium Complex: Synergistic Effects in Photodynamic Therapy Application
Authors: Maranho Daniela Silva , De Lima Renata Galvão , Primo Fernando Lucas , Da Silva Roberto Santana , Tedesco Antonio Claudio
Published: December 2008

Under continuous photolysis at 675 nm, liposomal zinc phthalocyanine associated with nitrosyl ruthenium complex [Ru(NH.NHq)(tpy)NO]3+showed the detection and quantification of nitric oxide (NO) and singlet oxygen (1O2) release. Photophysical and photochemical results demonstrated that the interaction between the nitrosyl ruthenium complex and the photosensitizer can enable an electron transfer process from the photosensitizer to the nitrosyl ruthenium complex which leads to NO release. Synergistic action of both photosensitizers and the nitrosyl ruthenium complex results in the production of reactive oxygen species and reactive nitrogen species, which is a potent oxidizing agent to many biological tissues, in particular neoplastic cells.
Differential Expression Profiles of microRNAs in NIH3T3 Cells in Response to UVB Irradiation
Authors: Guo Ling , Huang Zhong‐Xi , Chen Xiao‐Wei , Deng Qin‐Kai , Yan Wei , Zhou Mei‐Juan , Ou Cheng‐Shan , Ding Zhen‐Hua
Published: December 2008

MicroRNAs (miRNAs) are known as a kind of small, noncoding RNA, which play an important role in mediating many biological processes such as development, cell proliferation and differentiation in plants and animals. Here we report the differential expression profiles of miRNAs and characterized putative target genes in NIH3T3 cells at a series of different time points after UVB irradiation (compared with no UVB irradiation). The relative expression of mature miRNA genes was determined by miRNA microarray technique and the results were confirmed by real‐time reverse transcriptase polymerase chain reaction (qRT‐PCR). Potential target genes of these miRNAs were classified into different function categories with the GOstat software (http://gostat.wehi.edu.au/cgi‐bin/goStat.pl). Several miRNAs in this study expressed highly at different time points, especially mmu‐miR‐365 and mmu‐miR‐21. Three miRNAs were lowly expressed, of which mmu‐miR‐465 showed low levels of expression at all time points, whereas after 50 J m−2 UVB irradiation mmu‐miR‐296 and mmu‐miR‐376c showed low levels of expression at 6 and 12 h, respectively. Our study provided a basis for the global characterization of UV‐regulated miRNA expression.
Ultraviolet Radiation‐induced Transcription is Associated with Gene‐specific Histone Acetylation
Authors: Pollack Brian P. , Sapkota Bishu , Boss Jeremy M.
Published: December 2008

UVR is an important environmental carcinogen and a powerful modulator of the cutaneous immune system. Exposure to UVR activates many signaling pathways leading to changes in the expression of several hundred genes. While the covalent modification of histones has been shown to play a central role in regulating gene expression, the impact of UVR on histone modifications and the contribution of histone acetyltransferases (HATs) and histone deacetylases (HDACs) to the UVR‐induced transcriptional response have not been completely characterized. In this report, we have examined the impact of UVR on histone H3 K9/14 acetylation. The potential role of UVR‐induced histone acetylation in the UVR transcriptional response was also explored using the HAT inhibitor curcumin and HDAC inhibitor trichostatin A (TSA). We found that UVR caused an increase in histone H3 acetylation within the promoter regions of ATF3, COX2, IL‐8, MKP1 and MnSOD. In most of the regions examined, histone H3 acetylation peaked 24 h after UVR and then returned to baseline levels by 72 h. The induction of ATF3, COX2 and MKP1 was blocked in the presence of curcumin at doses that decreasein vivohistone H3 acetylation but not at lower doses that do not affect acetylation levels. We also provide evidence that for ATF3, a transcriptional superinduction occurs after repeat exposures to UVR that can be recapitulated when the second UVR exposure is replaced with TSA treatment. Thus, UVR can alter histone acetylation within human keratinocytes and these changes may contribute to the UVR‐transcriptional response.
Rapid evolution in crop‐weed hybrids under artificial selection for divergent life histories
Authors: Campbell Lesley G. , Snow Allison A. , Sweeney Patricia M. , Ketner Julie M.
Published: December 2008

When species hybridize, offspring typically exhibit reduced fitness and maladapted phenotypes. This situation has biosafety implications regarding the unintended spread of novel transgenes, and risk assessments of crop‐wild hybrids often assume that poorly adapted hybrid progeny will not evolve adaptive phenotypes. We explored the evolutionary potential of early generation hybrids using nontransgenic wild and cultivated radish (Raphanus raphanistrum,Raphanus sativus) as a model system. We imposed four generations of selection for two weedy traits – early flowering or large size – and measured responses in a common garden in Michigan, USA. Under selection for early flowering, hybrids evolved to flower as early as wild lineages, which changed little. These early‐flowering hybrids also recovered wild‐type pollen fertility, suggesting a genetic correlation that could accelerate the loss of crop traits when a short life cycle is advantageous. Under selection for large size at reproduction, hybrids evolved longer leaves faster than wild lineages, a potentially advantageous phenotype under longer growing seasons. Although early generation hybrid offspring have reduced fitness, our findings provide novel support for rapid adaptation in crop‐wild hybrid populations. Biosafety risk assessment programs should consider the possibility of rapid evolution of weedy traits from early generations of seemingly unfit crop‐wild hybrids.
Sensitivity Analysis of Combustion Timing of Homogeneous Charge Compression Ignition Gasoline Engines
Authors: Chiang Chia-Jui , Stefanopoulou Anna G.
Published: December 2008

The goal of this paper is to identify the dominant factors that should be included in a control oriented model in order to predict the start of combustion in a homogeneous charge compression ignition (HCCI) engine. Qualitative and quantitative information on the individual effects of fuel and exhaust gas recirculation on the HCCI combustion is provided. Using sensitivity analysis around a wide range of operating conditions of a single-cylinder port-injection gasoline HCCI engine, we find that temperature is the dominant factor in determining the start of combustion. Charge temperature thus becomes the “spark” in a HCCI engine. Therefore, a model without the composition terms should be adequate for model based regulation of the combustion timing in a port-injection gasoline HCCI engine with high dilution from the exhaust.
Design and Development of a Novel 2DOF Actuation Slosh Rig
Authors: Gandhi Prasanna S. , Joshi Keyur B. , Ananthkrishnan N.
Published: December 2008

Sloshing of liquid in a tank is critical in several areas, including launch vehicles carrying liquid fuel, satellites, industrial packaging of liquids, systems handling molten metal, and so on. Hence modeling, characterization, and control of nonlinear slosh phenomena are important in these applications. To study slosh dynamics, develop useful identification schemes, and design and verify slosh control algorithms, a new 2DOF actuation slosh rig is reported in this paper considering the fact that most of the times these tanks are subjected to linear as well as pitching excitation/control inputs. The paper discusses mechatronic design and several advantages that the new design offers. A slosh phenomenon of beating observed when both lateral and pitching excitations are provided is simulated using a model based on pendulum approximation to slosh and is further verified in experiments. The results confirm that the effects of both excitations together can be detrimental against separate excitations of the same amplitude. Moreover, slosh compensation in open loop is demonstrated by giving excitation in pitching and developing a compensatory input in the lateral direction. Furthermore, active slosh control strategy is developed and its effectiveness is demonstrated with control in translation and disturbance in pitching. Thus the proposed rig is an ideal tool for the study, identification, and control development of slosh in the presence of two excitations/inputs.
Indicated Mean Effective Pressure Estimator Order Determination and Reduction When Using Estimated Engine Statistics
Authors: Arbuckle J. S. , Burl J. B.
Published: December 2008

The indicated mean effective pressure (IMEP) is typically used as an engine running quality metric. IMEP depends on cylinder pressure, which is costly to measure, therefore it is useful to estimate IMEP from currently measured crankshaft encoder data. In this paper, the difficulties in developing an optimal linear estimator from acceleration computed from crankshaft rotational speed and cylinder pressure data are discussed, and strategies are presented to reduce these difficulties. Estimating IMEP from crankshaft data requires the determination of which data to use in the estimator. Without this step, the estimator can become unnecessarily complex due the inclusion of strongly correlated data points in the estimator. A strategy to determine the angular location of the acceleration points to use is presented and is shown to greatly reduce the estimator complexity without significantly affecting estimation error. Additionally, while increasing the estimator order usually decreases the estimation error, it will be shown that increasing the estimator order can actually increase the estimation error. This effect is due to uncertainties in the gains of the estimator. These uncertainties in the gains can result from using limited training data to estimate the statistics necessary to compute the gains or when dealing with a nonstationary system. A method of reducing the effect of these uncertainties by optimizing the estimator order based on the number of available training data cycles is developed and demonstrated.
Sliding Mode Control of Mechanical Systems Actuated by Shape Memory Alloy
Authors: Ashrafiuon Hashem , Jala Vijay Reddy
Published: December 2008

This paper presents a model-based sliding mode control law for mechanical systems, which use shape memory alloys (SMAs) as actuators. The systems under consideration are assumed to be fully actuated and represented by unconstrained equations of motion. A system model is developed by combining the equations of motion with SMA heat convection, constitutive law, and phase transformation equations, which account for hysteresis. The control law is introduced using asymptotically stable second-order sliding surfaces. Robustness is guaranteed through the inclusion of modeling uncertainties in the controller development. The control law is developed assuming only positions are available for measurement. The unmeasured states, which include velocities and SMA temperatures and stresses, are estimated using an extended Kalman filter based on the nonlinear system model. The control law is applied to a three-link planar robot for position control problem. Simulation and experimental results show good agreement and verify the robustness of the control law despite significant modeling uncertainty.
Reduced-Order Model-Based Feedback Control of Flow Over an Obstacle Using Center Manifold Methods
Authors: Kasnakoğlu Coşku , Camphouse R. Chris , Serrani Andrea
Published: December 2008

In this paper, we consider a boundary control problem governed by the two-dimensional Burgers’ equation for a configuration describing convective flow over an obstacle. Flows over obstacles are important as they arise in many practical applications. Burgers’ equations are also significant as they represent a simpler form of the more general Navier–Stokes momentum equation describing fluid flow. The aim of the work is to develop a reduced-order boundary control-oriented model for the system with subsequent nonlinear control law design. The control objective is to drive the full order system to a desired 2D profile. Reduced-order modeling involves the application of an L2 optimization based actuation mode expansion technique for input separation, demonstrating how one can obtain a reduced-order Galerkin model in which the control inputs appear as explicit terms. Controller design is based on averaging and center manifold techniques and is validated with full order numerical simulation. Closed-loop results are compared to a standard linear quadratic regulator design based on a linearization of the reduced-order model. The averaging∕center manifold based controller design provides smoother response with less control effort and smaller tracking error.
Intermittent Predictive Steering Control as an Automobile Driver Model
Authors: Roy Rene , Micheau Philippe , Bourassa Paul
Published: December 2008

The originality of this paper is the evaluation of intermittent control as a viable candidate to represent an automobile driver in a path tracking scenario. The control algorithm is based on general predictive control where the road curvature is considered known for a horizon in front of the automobile. The computed steering wheel command is used in an intermittent fashion, the intermittence period being one of the system parameter to study. Simulations are carried out and parameters of the driver, the automobile, and the road are varied. An intermittence period range giving satisfactory performances is observed. A comparison is made with actual car/driver behavior measurements for a lane change maneuver. It is concluded that, according to this driver model, there is a wide range of intermittence period that the automobile driver may be operating. Moreover, it is suggested to consider the intermittency of information as an important parameter for vehicle safety systems.
Feedback Linearization Based Generalized Predictive Control of Jupiter Icy Moons Orbiter
Authors: Shi Jianjun , Kelkar Atul G.
Published: December 2008

This paper presents a nonlinear dynamic model of Jupiter Icy Moons Orbiter (JIMO), a concept design of a spacecraft intended to orbit the three icy moons of Jupiter, namely, Europa, Ganymede, and Callisto. The work in this paper represents a part of the feasibility study conducted to assess control requirements for the JIMO mission. A nonlinear dynamic model of JIMO is derived, which includes rigid body as well as flexible body dynamics. This paper presents a novel hybrid control strategy, which combines feedback linearization with generalized predictive control methodology in a two-step approach for attitude control of the spacecraft. This feedback linearization based generalized predictive control (FLGPC) law is used to accomplish a representative realistic in-orbit maneuver to test the efficacy of the controller. The controller performance shows that the FLGPC is a viable methodology for attitude control of a similar class of spacecraft. The results presented are a part of exhaustive study conducted to evaluate various controller designs.
Safe Control of Hopping in Uneven Terrain
Authors: Howley Brian , Cutkosky Mark
Published: December 2008

Using a classic problem from robotics of a vertical hopping machine, we demonstrate an approach for investigating the safety of a hybrid discrete/continuous dynamic system operating in an uncertain environment. The challenges imposed by the environment are expressed in terms of constraints imposed in the phase space of the system as it undergoes periodic motion. The approach is demonstrated first with a hopper that has state feedback to govern the timing of thrust and subsequently for a timer-based hopper. The latter case increases the dimensionality of the problem and must be treated numerically. However, the use of a multiresolution surface representation of the feasible regions in state space reduces the computational burden of the approach.
Local L2 Gain of Axial Flow Compressor Control
Authors: Yang Tiebao , Chen Xiang
Published: December 2008

Feedback control has been pursued to stabilize the bifurcated operating solution near the rotating stall point in axial-flow compressors. These controllers can extend the stable operating range and hence improve engine performance. However, the local L2 gain of these controllers still remains unknown. In this paper, a family of Lyapunov functions is first constructed, and then the local L2 gain is derived through Hamilton–Jacobi–Bellman inequality for a class of stabilizing controllers with throttle position as actuator and pressure rise as measurement. The results obtained in this paper provide useful guidance for selecting the most robust controller from a given class of stabilizing controllers in terms of L2 gain.
Predictors of Mammographic Density: Insights Gained from a Novel Regression Analysis of a Twin Study
Authors: Dite Gillian S. , Gurrin Lyle C. , Byrnes Graham B. , Stone Jennifer , Gunasekara Anoma , McCredie Margaret R.E. , English Dallas R. , Giles Graham G. , Cawson Jennifer , Hegele Robert A. , Chiarelli Anna M. , Yaffe Martin J. , Boyd Norman F. , Hopper John L.
Published: December 2008

Understanding which factors influence mammographically dense and nondense areas is important because percent mammographic density adjusted for age is a strong, continuously distributed risk factor for breast cancer, especially when adjusted for weight or body mass index. Using computer-assisted methods, we measured mammographically dense areas for 571 monozygotic and 380 dizygotic Australian and North American twin pairs ages 40 to 70 years. We used a novel regression modeling approach in which each twin's measure of dense and nondense area was regressed against one or both of the twin's and co-twin's covariates. The nature of changes to regression estimates with the inclusion of the twin and/or co-twin's covariates can be evaluated for consistency with causal and/or other models. By causal, we mean that if it were possible to vary a covariate experimentally then the expected value of the outcome measure would change. After adjusting for the individual's weight, the co-twin associations with weight were attenuated, consistent with a causal effect of weight on mammographic measures, which in absolute log cm2/kg was thrice stronger for nondense than dense area. After adjusting for weight, later age at menarche, and greater height were associated with greater dense and lesser nondense areas in a manner inconsistent with causality. The associations of dense and nondense areas with parity are consistent with a causal effect and/or within-person confounding. The associations between mammographic density measures and height are consistent with shared early life environmental factors that predispose to both height and percent mammographic density and possibly breast cancer risk. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3474–81)
Flaxseed Supplementation (Not Dietary Fat Restriction) Reduces Prostate Cancer Proliferation Rates in Men Presurgery
Authors: Demark-Wahnefried Wendy , Polascik Thomas J. , George Stephen L. , Switzer Boyd R. , Madden John F. , Ruffin Mack T. , Snyder Denise C. , Owzar Kouros , Hars Vera , Albala David M. , Walther Philip J. , Robertson Cary N. , Moul Judd W. , Dunn Barbara K. , Brenner Dean , Minasian Lori , Stella Philip , Vollmer Robin T.
Published: December 2008

Background: Prostate cancer affects one of six men during their lifetime. Dietary factors are postulated to influence the development and progression of prostate cancer. Low-fat diets and flaxseed supplementation may offer potentially protective strategies.

Methods: We undertook a multisite, randomized controlled trial to test the effects of low-fat and/or flaxseed-supplemented diets on the biology of the prostate and other biomarkers. Prostate cancer patients (n = 161) scheduled at least 21 days before prostatectomy were randomly assigned to one of the following arms: (a) control (usual diet), (b) flaxseed-supplemented diet (30 g/d), (c) low-fat diet (<20% total energy), or (d) flaxseed-supplemented, low-fat diet. Blood was drawn at baseline and before surgery and analyzed for prostate-specific antigen, sex hormone-binding globulin, testosterone, insulin-like growth factor-I and binding protein-3, C-reactive protein, and total and low-density lipoprotein cholesterol. Tumors were assessed for proliferation (Ki-67, the primary endpoint) and apoptosis.

Results: Men were on protocol an average of 30 days. Proliferation rates were significantly lower (P < 0.002) among men assigned to the flaxseed arms. Median Ki-67-positive cells/total nuclei ratios (×100) were 1.66 (flaxseed-supplemented diet) and 1.50 (flaxseed-supplemented, low-fat diet) versus 3.23 (control) and 2.56 (low-fat diet). No differences were observed between arms with regard to side effects, apoptosis, and most serologic endpoints; however, men on low-fat diets experienced significant decreases in serum cholesterol (P = 0.048).

Conclusions: Findings suggest that flaxseed is safe and associated with biological alterations that may be protective for prostate cancer. Data also further support low-fat diets to manage serum cholesterol. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3577–87)