bluuebunny/crossref_metadata_2025_split huggingface dataset:
ENDOTHELIUM‐TARGETED TRANSGENIC GTP‐CYCLOHYDROLASE I OVEREXPRESSION INHIBITS NEOINTIMA FORMATION IN MOUSE CAROTID ARTERY
Authors: Liao Song‐Jie , Lin Li , Zeng Jin‐Sheng , Huang Ru‐Xun , Channon Keith M , Chen Alex F 
Published: August 2007

SUMMARY

Tetrahydrobiopterin (BH4) is an essential cofactor that maintains the normal function of endothelial nitric oxide (NO) synthase. Restenosis is a key complication after transluminal angioplasty. Guanosine 5′‐triphosphate‐cyclohydrolase I (GTPCH) is the first rate‐limiting enzyme for de novo BH4 synthesis. However, the role of GTPCH in restenosis is not fully understood. The present study tested the hypothesis that endothelial‐targeted GTPCH overexpression retards neointimal formation, a hallmark of restenosis, in mouse carotid artery.
Transluminal wire injury was induced in the left carotid arteries of adult male wild‐type C57BL/6 (WT) and endothelial GTPCH transgenic (Tg‐GCH) mice. Re‐endothelialization was confirmed with in vivo Evans blue staining. Endothelium‐dependent and ‐independent relaxations were measured using isometric tension recording. Morphological analysis was performed 2 and 4 weeks after carotid injury to assess neointimal formation. Fluorescence‐based high‐performance liquid chromatography (HPLC) was used to determine GTPCH activity and BH4 levels. Basal NO release following carotid injury was assessed by NG‐nitro‐l‐arginine methyl ester‐induced vascular contraction.
The endothelium was completely removed upon transluminal wire injury and full re‐endothelialization was achieved at Day 10. Endothelium‐dependent relaxation was impaired 10 days and 4 weeks after carotid injury, whereas endothelium‐independent relaxation remained unaffected. Morphological analysis revealed that the endothelial‐specific overexpression of GTPCH reduced neointimal formation and medial hypertrophy 2 and 4 weeks after carotid injury. Both arterial GTPCH enzyme activity and BH4 levels were significantly elevated in Tg‐GCH mice compared with WT mice and basal NO release of the injured carotid artery tended to increase in Tg‐GCH mice.
These findings suggest that the endothelial overexpression of GTPCH increased endothelial BH4 synthesis and played a preventive role in neointimal formation induced by endothelium denudation.
DETECTION OF PERIVASCULAR BLOOD FLOW IN VIVO BY CONTRAST‐ENHANCED INTRACORONARY ULTRASONOGRAPHY AND IMAGE ANALYSIS: AN ANIMAL STUDY
Authors: Vavuranakis Manolis , Papaioannou Theodore G , Kakadiaris Ioannis A , O'Malley Sean M , Naghavi Morteza , Filis Konstantinos , Sanidas Elias A , Papalois Apostolos , Stamatopoulos Ilias , Stefanadis Christodoulos 
Published: August 2007

SUMMARY

Acute coronary syndromes are mostly the result of coronary plaque rupture. Diagnostic techniques focusing on the early detection of those plaques that are prone to rupture are still limited. Increased neovascularization in the adventitia and within the atherosclerotic plaque have recently been identified as common features of inflammation and plaque vulnerability. Contrast‐enhanced intravascular imaging with microbubbles can be used to trace perfusion.
In the present study, we examined the perivascular network of the left anterior descending coronary arteries and left circumflex arteries of four domestic, clinically healthy pigs using intracoronary ultrasound after injection of microbubbles with a differential imaging technique (ACES™; Computational Biomedicine Laboratory, University of Houston, Houston, TX, USA). Our aim was to detect blood flow into the coronary lumen and perivascular flow in contrast‐enhanced images. Eleven regions of interest (ROI), including perivascular structures, were compared with regard to their grey scale level before and after the injection of SonoVue® (0.06 mL/kg; Bracco Diagnostics, Princeton, NJ, USA).
A statistically significant (P = 0.018) enhancement was found in the echogenicity of the total perivascular space (adventitial region and perivascular vessels), as indicated by an increase in grey level intensity from 8.33 ± 0.80 (before) to 10.11 ± 0.88 (after microbubble injection). A significant enhancement of the 11 selected ROI (perivascular structures) was also recorded after the injection of microbubbles (from 7.92 ± 2.14 to 14.03 ± 2.44; P = 0.008).
We believe that the detection of perivascular structures with contrast‐enhanced intracoronary ultrasonography combined with proper image processing may reinforce our future efforts in the detection of vasa vasorum, an active participant in the creation of acute coronary events.
INHIBITORY INTERNEURONS IN THE PIRIFORM CORTEX
Authors: Suzuki Norimitsu , Bekkers John M 
Published: August 2007

SUMMARY

The piriform cortex (PC) is the largest subdivision of the olfactory cortex and the first cortical destination of olfactory information. Despite the relatively simple anatomy of the PC and its obvious appeal as a model system for the study of cortical sensory processing, there are many outstanding questions about its basic cell physiology. In the present article, we review what is known about GABAergic inhibitory interneurons in the PC.
The GABA‐containing neurons in the PC are morphologically diverse, ranging from small neurogliaform cells to large multipolar forms. Some of these classes are distributed across all three main layers of the PC, whereas others have a more restricted laminar expression.
Distinct and overlapping populations of GABAergic basket cells in Layers II and III of the PC express different combinations of calcium‐binding proteins and neuropeptides. Few Layer I interneurons express any of the molecular markers so far examined.
The intrinsic firing properties of one or two types of putative PC interneurons have been measured and inhibitory post‐synaptic responses have been recorded in PC pyramidal cells following extracellular stimulation. However, little is known about the physiology of the subtypes of interneurons identified.
In view of the likely importance of PC interneurons in olfactory learning, olfactory coding and epileptogenesis, further investigation of their properties is likely to be highly informative.
EVIDENCE FOR THE REGULATION OF L‐TYPE Ca2+ CHANNELS IN THE HEART BY REACTIVE OXYGEN SPECIES: MECHANISM FOR MEDIATING PATHOLOGY
Authors: Hool Livia C 
Published: August 2007

SUMMARY

It is well recognized that reactive oxygen species (ROS) can activate transduction pathways to mediate pathophysiology. An increase in ROS has been implicated in a number of cardiovascular disorders. Reactive oxygen species regulate cell function through redox modification of target proteins. One of these target proteins is the L‐type Ca2+ channel.
There is good evidence that thiol reducing and oxidizing compounds, including hydrogen peroxide, can influence calcium channel function. The evidence for regulation of the channel protein and regulatory proteins by thiol‐specific modifying agents and relevance to hypoxia and oxidative stress is presented.
Clinical studies suggest that calcium channel antagonists may be beneficial in reducing myocardial injury associated with oxidative stress. The identification of cysteines as possible targets for intervention during hypoxic trigger of arrhythmia or chronic pathological remodelling is discussed.
EFFECT OF GENDER AND SEX HORMONES ON VASCULAR OXIDATIVE STRESS
Authors: Miller Alyson A , De Silva T Michael , Jackman Katherine A , Sobey Christopher G 
Published: August 2007

SUMMARY

It is well documented that the incidence and severity of several vascular diseases, such as hypertension, atherosclerosis and stroke, are lower in premenopausal women than men of similar age and post‐menopausal women. The mechanisms responsible for gender differences in the incidence and severity of vascular disease are not well understood. However, emerging evidence suggests that sex hormone‐dependent differences in vascular oxidative stress may play an important role. The aim of the present brief review is to provide an insight into the effect of gender and sex hormones on vascular oxidative stress.
When production of reactive oxygen species (ROS) is enhanced and/or their metabolism by anti‐oxidant enzymes is impaired, a condition known as ‘oxidative stress’ can develop. Oxidative stress is believed to play an important role in both the initiation and progression of a variety of vascular diseases, including hypertension and atherosclerosis. NADPH oxidases are believed to be the major source of vascular ROS. Moreover, excessive production of ROS by NADPH oxidases has been linked to the development of vascular oxidative stress.
Increasing evidence suggests that levels of vascular ROS may be lower in women than men during health and disease. Indeed, the activity and expression of vascular NADPH oxidase is lower in female versus male animals under healthy, hypertensive and atherosclerotic conditions.
Gonadal sex hormones may play an important role in the regulation of vascular oxidative stress. For example, oestrogens, which are present in highest levels in premenopausal women, have been reported to lower vascular oxidative stress by modulating the expression and function of NADPH oxidases, as well as anti‐oxidant enzymes.
Further studies are needed to clarify whether lower vascular oxidative stress in women in fact protects against the initiation and development of vascular disease and to further define the roles of gonadal sex hormones in such an effect. Knowledge gained from these studies may potentially lead to advances in the clinical diagnosis and treatment of vascular disease in both genders.
COMBINED SPINAL AND EPIDURAL ANAESTHESIA WITH CHLOROPROCAINE FOR HYSTERECTOMY
Authors: Fu Run‐Qiao , Tian Yu‐Ke , Fang Wei‐Ran 
Published: August 2007

SUMMARY

The aim of the present study was to determine the clinical efficacy and safety of chloroprocaine (CP) for gynaecological surgery.
One hundred and twenty gynaecological patients scheduled for hysterectomy were divided randomly into four groups: Group A (n = 30), 2.5% CP 1.0 mL; Group B (n = 30), 2.5% CP 1.2 mL; Group C (n = 30), 2.5% CP 1.4 mL; and Group D (n = 30), 2.5% CP 1.6 mL. The dose of CP used in each group was mixed with 1 mL vehicle containing 5% glucose and 1.5% ephedrine. Spinal anaesthesia was achieved by lumbar puncture in the L2–3 interspace and injection of the mixture. Wherever necessary, CP (2.5%) was used for epidural anaesthesia.
Although the times to onset and peak effect, as well as the grade of motor block of the lower limbs (Bromage scale), were similar among the four groups, the level of the highest sensory nerve block increased gradually, from T7 (± 1), T6 (± 1), T4 (± 1) to T3 (± 1) in Groups A, B, C and D, respectively. The rate of unsatisfactory spinal anaesthesia was 80 and 16.7% in Groups A and B, respectively, and consequently epidural anaesthesia was superimposed in those patients for surgery to start. Spinal anaesthesia was very satisfactory for surgery in Groups C and D. In contrast, the incidence of hypotension in Groups B, C and D was 6.7, 16.7 and 67.7%, respectively; however, respiratory depression only occurred in Group D in nine cases (30%). No other adverse events or neurologic deficits were found.
The present results suggest that 30–35 mg CP in a total volume of 2.2–2.4 mL used for spinal anaesthesia in hysterectomy is safe and efficient. The combination of spinal and epidural anaesthesia with 2.5% CP can achieve 100% satisfactory anaesthesia for this type of surgery.
IMMUNOCHEMICAL CHARACTERIZATION OF THE FUNCTIONAL CONSTITUENTS OF TRIPTERYGIUM WILFORDII CONTRIBUTING TO ITS ANTI‐INFLAMMATORY PROPERTY
Authors: Wong Kwong‐Fai , Chan Jacqueline K , Chan Kwong‐Leung , Tam Paul , Yang Dan , Fan Sheung‐Tat , Luk John M 
Published: August 2007

SUMMARY

Tripterygium wilfordii (TW) contains bioactive compounds that possess immunosuppressive properties. These compounds are considered to be potential drugs in the treatment of acute graft rejections. However, their structure–activity relationships remain unknown.
The aim of the present study was to delineate the molecular moieties of triptolide that could account for its ability to inhibit inflammatory responses. In this context, purified TW active compounds (triptolide and triptonide) and synthetic triptolide derivatives were prepared to investigate the structure–activity relationships of triptolide. To this end, rat splenocytes were treated with increasing concentrations of the compounds and then allogenically stimulated using a mixed lymphocyte reaction to determine their antiproliferative activities. From the results, the IC50 value of each compound was calculated.
Modification of the β‐hydroxyl group at the C‐14 position of the triptolide molecule significantly affected the immunosuppressive activity of T59, as demonstrated by a sevenfold increase of the IC50. Conversely, reduction of the γ‐butyrolactone group in T60 and T61 completely abrogated the antiproliferative effect. Alterations in the C‐14 β‐hydroxyl and γ‐butyrolactone groups also resulted in reduced cytotoxicity.
The present findings demonstrate that the C‐14 β‐hydroxyl and γ‐butyrolactone moieties of the triptolide molecule are crucial for its anti‐inflammatory properties and cytotoxicity and are responsible for the compound's antiproliferative activity.
EFFECT OF POLYPHENOL‐CONTAINING AZUKI BEAN (VIGNA ANGULARIS) EXTRACT ON BLOOD PRESSURE ELEVATION AND MACROPHAGE INFILTRATION IN THE HEART AND KIDNEY OF SPONTANEOUSLY HYPERTENSIVE RATS
Authors: Sato Shin , Mukai Yuuka , Yamate Jyoji , Kato Jun , Kurasaki Masaaki , Hatai Asako , Sagai Masaru 
Published: August 2007

SUMMARY

Hypertension is a major risk factor for myocardial infarction and renal damage, and it has also been shown to have pro‐inflammatory actions that increase the formation of reactive oxygen species. Macrophage infiltration has been suggested to play a role in the pathogenesis of hypertension. Azuki beans are known to contain pro‐anthocyanidins, a group of polyphenolic bioflavonoids with remarkable radical‐scavenging activities in vitro. Therefore, the aim of the present study was to investigate the effect of polyphenol‐containing azuki bean extract (ABE) on systolic blood pressure (SBP) and macrophage infiltration in the heart and kidney of spontaneously hypertensive rats (SHR).
Spontaneously hypertensive rats and control normotensive Wistar‐Kyoto (WKY) rats were divided into two groups fed either 0 or 0.8% ABE in their diets. Tail SBP and macrophage kinetics in the heart and kidney were examined.
The SBP of the SHR group was higher than that of age‐matched WKY rats throughout the treatment period. After 8 weeks of treatment, the increased SBP in ABE‐treated SHR was significantly less than that in untreated SHR.
Nicotinamide adenine dinucleotide (NADH) or nicotinamide adenine dinucleotide phosphate (NADPH)‐stimulated superoxide () production was enhanced in the kidney and heart in SHR and WKY rats compared with levels in the absence of NADH or NADPH. The NADPH‐stimulated levels in the kidney in untreated SHR was significantly higher than that in untreated WKY rats. The levels in ABE‐treated SHR were significantly decreased compared with the untreated SHR group.
In immunohistochemical analyses, the number of macrophages in the heart and in the glomeruli and tubulointerstitium of the kidney was significantly higher in ABE‐untreated SHR than in ABE‐untreated WKY rats. Conversely, there was a significant decrease in the number of macrophages in ABE‐treated SHR compared with the untreated SHR. There were significant positive correlations between SBP and the number of ED1‐positve macrophages in the heart and tubulointerstitial and glomerular areas of the kidney in WKY rats and SHR.
In conclusion, the results of the present study suggest that ABE attenuates the elevation of SBP and macrophage infiltration in the heart, as well as in the glomeruli and tubulointerstitium of the kidney, in our SHR model.
Outcomes after medical and surgical treatment of diverticulitis: A systematic review of the available evidence
Authors: Peppas George , Bliziotis Ioannis A , Oikonomaki Dora , Falagas Matthew E 
Published: August 2007

AbstractThere is still controversy regarding the appropriate management of diverticulitis of the colon in cases when both surgical and conservative treatment may be an option.We performed a systematic review of the available evidence regarding the outcomes after medical and surgical treatment of diverticulitis from studies published after 1980 and indexed in the PubMed database. We included original studies that reported comparative data for at least one outcome in medically‐ and surgically‐treated patients with transverse or left colon diverticulitis. The main outcomes of interest were mortality, morbidity, and recurrence of diverticulitis after medical or surgical treatment.There were 21 studies fulfilling our inclusion criteria out of 1360 initially identified as possibly relevant. More patients were treated conservatively in the included studies compared to emergency surgery (24 862 vs 6504). Emergency surgery was the main option for patients with severe complications of diverticular disease, including peritonitis. In most studies, in‐hospital mortality for patients treated surgically was generally higher than that of patients treated medically, whereas there were insufficient comparative data regarding mortality during follow up. However, readmission to the hospital due to diverticular disease during follow up was more common in the group of patients treated conservatively compared to those treated surgically (4358/23 446 [18.6%]vs 22/359 [6.1%]). Conservatively‐treated patients, with a first or second episode of diverticulitis, required surgery for recurrent disease during follow up in a maximum of 45% of cases, with larger studies reporting percentages lower than 11%.It should be emphasized that medical and surgical treatments have not ever been compared in a randomized controlled trial in patients with diverticulitis (without generalized peritonitis that is a surgical emergency). Although medical treatment results in more readmissions due to recurrence, it may be reasonable to avoid surgical therapy in the vast majority of patients with acute diverticulitis. It is unclear what the best treatment option is for younger patients (<50 years), namely whether elective surgery should be considered with the first episode of diverticulitis.
Quantitative Crack Surface Morphology of Bone Cements in Relation to Propagation Rate
Authors: ERANI PAOLO , CRISTOFOLINI LUCA , BALEANI MASSIMILIANO , BIGNOZZI MARIA CHIARA , COTIFAVA MARCO , IHADDADENE NABILA , TOMEI FEDERICO , VICECONTI MARCO 
Published: August 2007

ABSTRACTMorphology of the crack surface of surgical bone cements has seldom been studied in the past despite the clinical relevance of cement failure. Previous studies on a specific cement type suggest that crack morphology depends on crack propagation rate. The objectives of this work were: (i) to develop a quantitative indicator for describing crack morphology; and (ii) to assess if dependency on crack‐propagation rate is affected by cement formulation. Known crack surfaces were obtained from specimens under controlled loading conditions. Crack surface roughness was measured for different crack‐propagation rates, and compared against the amount of cleaved pre‐cured beads (measured with a semi‐automated procedure based on micrographs). Such indicators were extremely robust, operator‐independent, highly correlated, and sensitive to the type of fracture. Moreover, it was found that crack surface morphology heavily depends upon cement composition. Thus, crack surface roughness is proposed as a method for quantitatively identifying crack morphology, and finally classifying fracture type.
Strain‐life approach in thermo‐mechanical fatigue evaluation of complex structures
Authors: ROSA UROŠ , NAGODE MARKO , FAJDIGA MATIJA 
Published: August 2007

ABSTRACTThis paper is a contribution to strain‐life approach evaluation of thermo‐mechanically loaded structures. It takes into consideration the uncoupling of stress and damage evaluation and has the option of importing non‐linear or linear stress results from finite element analysis (FEA). The multiaxiality is considered with the signed von Mises method. In the developed Damage Calculation Program (DCP) local temperature‐stress‐strain behaviour is modelled with an operator of the Prandtl type and damage is estimated by use of the strain‐life approach and Skelton's energy criterion. Material data were obtained from standard isothermal strain‐controlled low cycle fatigue (LCF) tests, with linear parameter interpolation or piecewise cubic Hermite interpolation being used to estimate values at unmeasured temperature points. The model is shown with examples of constant temperature loading and random force‐temperature history. Additional research was done regarding the temperature dependency of the Kp used in the Neuber approximate formula for stress‐strain estimation from linear FEA results. The proposed model enables computationally fast thermo‐mechanical fatigue (TMF) damage estimations for random load and temperature histories.
Comparative assessment of fatigue and fracture behaviour of cast and forged railway wheels
Authors: TARAFDER S. , SIVAPRASAD S. , RANGANATH V. R. 
Published: August 2007

ABSTRACTA comparative evaluation of fatigue and fracture behaviour of commercially produced cast and forged rail wheels has been made using specimens extracted from various locations of the wheel quadrant. A systematic investigation in the web and rim regions of the wheel quadrant with various notch orientations showed that the forged material exhibited a better intrinsic resistance to fatigue crack growth than the cast material. Since linear elastic fracture mechanics (LEFM) based fracture toughness could not be validated for both the cast and forged wheel material, elastic plastic fracture mechanics (EPFM) based characteristic fracture toughness was used. Results showed that fracture resistance of the forged material is superior to that of the cast material. Cast wheel specimens exhibited unstable crack extension in comparison to substantial stable tearing in forged specimens. Microstructural and fractographic analyses showed that the cast wheel material contained large amounts of inclusions. The poor fracture resistance of cast wheel material is therefore attributed to the inferior material quality.
3D meso‐mechanical analysis of concrete specimens under biaxial loading
Authors: CABALLERO A. , CAROL I. , LÓPEZ C. M. 
Published: August 2007

ABSTRACTIn recent years, the mechanics of materials group at ETSECCPB‐UPC has developed an approach for meso‐mechanical analysis of concrete using zero‐thickness interface elements in 2D and more recently in 3D. In this methodology, the meso‐structure is generated with in‐house developed computer programs based on Voronoï/Delaunay theory. In the analysis, continuum elements are assumed linear elastic. Non‐linearity and fracture phenomena are made possible by the systematic use of zero‐thickness interface elements inserted on a priori determined potential fracture planes. In this paper, the results obtained for a 3D specimen under biaxial loading are presented. The results turn out to be very satisfactory and, in particular, it is observed that even the specimens which contain a reduced number of aggregates (14 in the present calculations) lead to a realistic failure envelope under biaxial loading, and they also capture the tendencies of cracking and fracture orientations observed in experiments for different rates of biaxial loading. The special limit case of biaxial loading under restrained out‐of‐plane deformations is also analysed, leading to practically elastic behaviour as shown by available experimental evidence.