bluuebunny/crossref_metadata_2025 huggingface dataset:
Endoscopic Management of Cerebrospinal Fluid Rhinorrhea
Authors: McMains Kevin C. , Gross Charles W. , Kountakis Stilianos E.
Published: September 2004

Purpose: Most anterior skull base defects causing cerebrospinal fluid (CSF) rhinorrhea can be readily approached using endoscopic techniques when surgical repair is necessary. We present our data from endoscopic repair of CSF rhinorrhea with long‐term follow‐up.

Methods: Retrospective data analysis of patients that were diagnosed with anterior skull base CSF rhinorrhea and underwent endoscopic repair at a tertiary institution. Data were analyzed to determine the etiology and location of CSF leaks. Diagnostic techniques, surgical techniques, and surgical outcomes were reviewed.

Results: Ninety‐two patients were diagnosed with CSF rhinorrhea and underwent endoscopic repair over a 12‐year period. Forty‐eight were males, and 44 were females. The average age was 49 (range 6–81) years. Average follow‐up was 25 months, with a range of 12 to 82 months. The etiology of CSF leak was prior endoscopic sinus surgery in 23 patients (25%), idiopathic in 19 (21%), neurosurgery in 17 (18%), trauma in 18 (20%), and the presence of meningocele/encephalocele in 11 patients (12%). The most common location of the defect was the sphenoid sinus (n = 36, 39%), followed by ethmoid roof (n‐27, 29%), and cribriform plate (n = 24, 26%). Endoscopic repair was initially successful in 78 (85%) patients. Seven additional patients underwent successful revision endoscopic repair for an overall success rate of 92% (n = 85). Five (6%) large skull base defects were eventually repaired by neurosurgery using open intracranial techniques. No major complications were encountered.

Conclusion: The intranasal endoscopic approach is an effective and safe technique in the surgical management of anterior skull base CSF rhinorrhea. Long‐term success rate in our patient population was 92%.
Relationships of Craniofacial Morphology and Body Mass Index with Sleep‐Disordered Breathing in Japanese Men
Authors: Yao Masayuki , Tachibana Naoko , Okura Mutsumi , Tanigawa Takeshi , Yamagishi Kazumasa , Ikeda Ai , Shimamoto Takashi , Iso Hiroyasu
Published: September 2004

Objective/Hypothesis: Obesity is an established risk factor for sleep‐disordered breathing, but the impact of craniofacial morphology is uncertain. The aim of this study was to assess the impact of craniofacial morphology and body weight on sleep‐disordered breathing in Japanese men.

Study Design: A cross‐sectional study.

Methods: We measured body mass index, seven cephalometric variables, and 3% oxygen desaturation index recorded by a pulse oximeter in 313 Japanese men aged 20 to 65 years who attended a sleep clinic. We defined craniofacial score as the sums of quartile points (0–3) for distance from sella to nasion and that from hyoid bone to mandibular plane.

Results: The mean value of 3% oxygen desaturation index and odds ratios of 3% oxygen desaturation index 15 or greater progressively increased with craniofacial score as well as body mass index. Multivariate odds ratios associated with craniofacial score were higher in men with body mass index 25.0 kg/m2 or greater (odds ratio = 4.2, 95% confidence interval [CI] = 2.1–8.6) than in men with lower body mass index (odds ratio = 1.6, 95% CI = 0.7–3.6).

Conclusions: Our results imply the importance of cephalometric assessment in overweight patients.
Risk of postpartum urinary incontinence associated with pregnancy and mode of delivery
Authors: Foldspang A. , Hvidman L. , Mommsen S. , Bugge Nielsen J.
Published: September 2004

Aim.  The aim was to estimate the postpartum urinary incontinence (PP UI) impact of precursory UI during pregnancy (PR UI) and delivery performed by cesarean section (CS) vs. vaginal childbirth (VC).

Methods.  Among the members of two population samples, in total 8610 women aged 20–59 years, 1232 had their first childbirth and 642 their second childbirth within 13–120 months prior to responding to a questionnaire that included information on PR UI occurrence, mode of delivery and PP UI occurrence.

Results.  CS was applied in 12.2% of first childbirths, and 87.8% thus delivered vaginally; PR UI during the pregnancy leading to the first childbirth was reported by 15.6%, and a total of 26.3% reported PP UI. An increased PP UI occurrence was reported following VC (28.3% vs. 12.0% in women undergoing CS, p < 0.001) and after PR UI (first childbirth, 66.7% vs. 18.8% in women not reporting PR UI, p < 0.0001). Among cases of PP UI following the first childbirth, 56.1% and 69.5% of cases could be attributed to PR UI and VC, respectively.

Conclusions.  The highest PP UI risks were found among women complaining of PR UI, which manifested itself as a crucial, independent precursor of PP UI. Because of the high frequency of VC, more than seven out of 10 cases of UI following the first childbirth, however, seemed to be attributable to VC. The present data did not lend significant support to the assumption that the PP UI risk is also lowered after a subsequent delivery by CS.
Stress urinary incontinence 4 years after the first delivery: a retrospective cohort survey
Authors: Fritel Xavier , Fauconnier Arnaud , Levet Caroline , Bénifla Jean‐Louis
Published: September 2004

Background.  Our aim was to estimate the prevalence of stress urinary incontinence 4 years after the first delivery and analyze its risk factors.

Methods.  A retrospective cohort survey was conducted in a French university hospital. The 669 primiparous women who delivered in our department in 1996 a singleton in a vertex position between 37 and 41 weeks of amenorrhea were included. A mailed questionnaire was sent 4 years after the indexed delivery. The main outcome measure was stress urinary incontinence 4 years after the first delivery.

Results.  Three hundred and seven women replied, 274 had moved and 88 did not respond. Four years after the first delivery, prevalence of stress urinary incontinence was 29% (89/307). According to multiple logistic regression analysis, the independent risk factors were urine leakage before the first pregnancy [odds ratio (OR) 18.7; 95% confidence interval (CI) 3.6–96.4], urine leakage during the first pregnancy (OR 2.5; 95% CI 1.3–4.8), duration of first labor ≥ 8 h (OR 3.1; 95% CI 1.7–5.7), mother's age > 30 years at the first delivery (OR 2.4; 95% CI 1.4–4.2) and cesarean section at the first delivery (OR 0.3; 95% CI 0.1–0.9).

Conclusion.  Our results suggest that stress urinary incontinence after pregnancy arises from a multifactorial condition. The main risk factors are: age, previous incontinence (before or during the first pregnancy), prolonged labor and vaginal delivery.
Sexual function in women before and after suburethral sling operation for stress urinary incontinence: a retrospective questionnaire study
Authors: Glavind Karin , Tetsche Mette Skytte
Published: September 2004

Background.  The aim of this questionnaire study dealing with women with stress urinary incontinence was to find out what influence incontinence and operation for incontinence in the form of tension‐free vaginal tape (TVT) or intravaginal slingplasty operation (IVS) had on the patient's sexuality and if there were any adverse effects on sexuality after the operation.

Methods.  Eighty‐four patients were operated on from April 1998 to September 2002. A questionnaire was sent to all patients with questions concerning their sexuality before and after the operation.

Results.  Sixty‐seven patients (81%) answered the questionnaire. Before the operation 53 patients (79%) were sexually active and 26 patients (49%) experienced incontinence during intercourse. Only one patient (0.01%) stated the incontinence as the reason for not being sexually active. No patients developed de novo incontinence during intercourse after the operation. Half of the patients who were cured of their incontinence during intercourse experienced a better sexual life. Five patients (7%) cited reduced libido after the operation and two patients (3%) felt the operation to be the cause.

Conclusion.  Among sexually active women with stress urinary incontinence referred for suburethral sling operation 49% experienced incontinence during intercourse and half of the cured patients in this group experienced a better sexual life after the operation. Incontinence affects sexual life to a great extend. Two patients (4%) experienced less libido after the operation and found the operation to be the cause of this. The risk of deterioration of sexual life after the operation is very small. Further investigation into this subject is needed.
The relationship between clinical parameters and health‐related quality of life as measured by the 15D in incontinent women before and after treatment*
Authors: Stach‐Lempinen Beata , Sintonen Harri , Kujansuu Erkki
Published: September 2004

Background.  The purpose of this study was to correlate the clinical parameters with a health‐related quality of life (HRQoL) measure and to describe the change of HRQoL caused by treatment and its modifying factors among urinary incontinent women.

Methods.  Eighty‐two incontinent women, referred to a tertiary gynecologic department, underwent clinical evaluation to establish diagnosis and severity of urinary incontinence (UI) and completed the generic 15D HRQoL instrument. Sixty‐nine women were re‐evaluated 13 months after treatment.

Results.  Compared to age‐matched female general population, the HRQoL of urinary incontinent women was significantly lower. Urge or mixed incontinence impairs HRQoL more than stress incontinence. The 15D scores correlated poorly with urodynamics, frequency/volume chart findings, and the amount of urine leakage. Among patients with stress UI (SUI), the HRQoL after treatment was the same as in the age‐matched general female population. Among women with urge or mixed UI, the HRQoL improved significantly after treatment but did not reach the HRQoL level of women with SUI at baseline. In stepwise regression analysis, lower the 15D score at baseline and bigger the decrease in urine leakage, greater was the change in HRQoL for the better.

Conclusion.  There was a modest correlation of incontinence severity measures with quality of life impairment. The challenge for the future will be to improve the success of treatment for women with urge UI. The generic 15D appears to be sensitive to detect change in HRQoL due to treatment of UI women.
Behavioural Effects in Rats after Prenatal Exposure to Dearomatized White Spirit
Authors: Hass Ulla , Ladefoged Ole , Lam Henrik R. , Østergaard Grete , Lund Søren Peter , Simonsen Leif
Published: September 2004

Abstract: The purpose of the study was to investigate the potential developmental neurotoxicity of the widely used organic solvent, white spirit. Rats (Mol:WIST) were exposed to 0 or 800 ppm dearomatized white spirit for 6 hr per day on gestation days 7–20. Developmental and neurobehavioural effects in the offspring were investigated using a test battery including assessment of physical development, reflex ontogeny, motor function, motor activity and, learning and memory. No significant effects were recorded on motor function and the activity in Open Field. In the initial learning period (age 1 month), the performance in a Morris water maze was similar in exposed and control animals. When testing for memory at the age of 2 months, the exposed male offspring used more time to locate the hidden platform. After platform relocation, impaired cognitive function was revealed in the exposed females. At the age of 5 months, learning and memory deficits were observed in exposed offspring. The differences were not related to poorer swimming capabilities, because swim speeds were similar to control values. The results show that prenatal exposure to 800 ppm white spirit caused long‐lasting learning and memory deficits in rats.
Including Spatial Heterogeneity and Animal Dispersal When Evaluating Hunting: a Model Analysis and an Empirical Assessment in an Amazonian Community
Authors: SIRÉN ANDERS , HAMBÄCK PETER , MACHOA JOSÉ
Published: September 2004

Abstract:  Hunting in tropical forests is typically most intense near human settlements, and this creates gradients of decreasing animal densities toward those settlements. Within the context of this spatial pattern, we evaluated the status of game in the hunting grounds of an indigenous community in eastern Ecuador. We constructed a spatially explicit model of hunter‐prey interactions that mimicked the hunting in the village and included realistic animal‐dispersal rules. We compared predictions from the model with distributions of animal harvest rates and catch per unit effort of 12 game species. Six species were overharvested in part or all of the area, and two other species were probably being overharvested, although high dispersal rates complicated the interpretation. We then compared our method with methods that have been used previously. We argue that because our method provides information about the spatial extent of overharvesting, it could be particularly useful in informing decision makers about where to establish no‐take areas and could therefore aid in improving the sustainability of hunting in tropical forests.
Shoreline Development Drives Invasion of Phragmites australis and the Loss of Plant Diversity on New England Salt Marshes
Authors: SILLIMAN BRIAN R. , BERTNESS MARK D.
Published: September 2004

Abstract:  The reed Phragmites australis Cav. is aggressively invading salt marshes along the Atlantic Coast of North America. We examined the interactive role of habitat alteration (i.e., shoreline development) in driving this invasion and its consequences for plant richness in New England salt marshes. We surveyed 22 salt marshes in Narragansett Bay, Rhode Island, and quantified shoreline development, Phragmites cover, soil salinity, and nitrogen availability. Shoreline development, operationally defined as removal of the woody vegetation bordering marshes, explained >90% of intermarsh variation in Phragmites cover. Shoreline development was also significantly correlated with reduced soil salinities and increased nitrogen availability, suggesting that removing woody vegetation bordering marshes increases nitrogen availability and decreases soil salinities, thus facilitating Phragmites invasion. Soil salinity (64%) and nitrogen availability (56%) alone explained a large proportion of variation in Phragmites cover, but together they explained 80% of the variation in Phragmites invasion success. Both univariate and aggregate (multidimensional scaling) analyses of plant community composition revealed that Phragmites dominance in developed salt marshes resulted in an almost three‐fold decrease in plant species richness. Our findings illustrate the importance of maintaining integrity of habitat borders in conserving natural communities and provide an example of the critical role that local conservation can play in preserving these systems. In addition, our findings provide ecologists and natural resource managers with a mechanistic understanding of how human habitat alteration in one vegetation community can interact with species introductions in adjacent communities (i.e., flow‐on or adjacency effects) to hasten ecosystem degradation.
Effects of Land Use on Bird Species Richness in Sulawesi, Indonesia
Authors: WALTERT MATTHIAS , MARDIASTUTI ANI , MÜHLENBERG MICHAEL
Published: September 2004

Abstract:  There is still much debate over the potential value of land‐use systems for the maintenance of tropical biodiversity. An increasing number of studies indicate that much forest biodiversity can also be found in the agricultural landscape matrix. Because there is little information on the potential value of land‐use systems for tropical forest bird species, we conducted repeated point counts in near‐primary forest, adjacent young secondary forest, modernized cacao agroforestry systems, and annual cultures at submontane elevations in central Sulawesi, Indonesia. Species richness decreased from natural forest and young secondary forest to agroforestry systems and annual cultures. Although species richness was similar between natural and young secondary forest, the number of endemic bird species was significantly lower in second‐growth forest. Species composition gradually changed as the habitat changed from natural to secondary forest, agroforestry systems, and annual cultures. Despite close proximity to near‐primary forest, the agroforestry systems studied supported only a few small frugivorous‐nectarivorous species. Our results suggest that secondary forest could play an important role in the conservation of many Sulawesi bird species, but, although suitable for colonization, its potential to sustain populations over the long term is unknown. Improvement of the landscape matrix for biodiversity conservation through secondary habitats therefore seems desirable to enlarge the ranges of forest species, but the fight against land conversion within protected areas of the region should be of much higher importance, at least at present.
Modeling Abundance Index Data from Anuran Calling Surveys
Authors: ROYLE J. ANDREW
Published: September 2004

Abstract:  Evaluation of anuran populations is commonly based on calling surveys that report categorical abundance index data. I present a statistical model for abundance index data that are observations representing ordered abundance classes (e.g., none, some, many). The proposed model provides a formal treatment of detection probability, factors that affect detection, and variation in abundance. The model can be viewed as a generalization of that proposed by MacKenzie et al. (2002) for estimating site‐occupancy rates in that it allows for more than two abundance classes. Because the abundance distribution is characterized by multiple abundance classes, it may be more sensitive to subtle changes in the underlying abundance that may go undetected with simple occupancy estimates under which sites are characterized merely as occupied or not. The method is most immediately applicable to surveys of anurans in which index data related to the intensity of calling activity are collected. I applied the proposed method to calling index data from the green frog ( Rana clamitans) collected as part of the North American Amphibian Monitoring Program. The best model indicated considerable variation in detectability over time and in response to temperature. The resulting adjusted (for detectability) abundance‐state distribution demonstrates the negative bias in abundance state obtained from simplistic summaries of calling index data that disregard these sources of variation in detectability.
Abundance and Species Richness of Nocturnal Insects on Organic and Conventional Farms: Effects of Agricultural Intensification on Bat Foraging
Authors: WICKRAMASINGHE LIAT P. , HARRIS STEPHEN , JONES GARETH , VAUGHAN JENNINGS NANCY
Published: September 2004

Abstract:  Insects are the principal food for many animals, including bats (Chiroptera), and all species of bats in the United Kingdom feed over agricultural habitats. Bat populations are declining throughout Europe, probably in part as a result of agricultural intensification. Organic farming prohibits the use of agrochemicals, a major component of agricultural intensification, making it an ideal control for a study of intensive agricultural systems. To evaluate the impact of agricultural intensification on bat foraging, we quantified the availability of bat prey by comparing nocturnal aerial insects captured within habitats on 24 matched pairs of organic and conventional farms. Insects were identified to family and moths to species. We compared the abundance of 18 insect families commonly eaten by bats in the United Kingdom between farm types and tested for correlations of abundance with bat activity. Insect abundance, species richness, and moth species diversity were significantly higher on organic farms than on conventional farms. Insect abundance was significantly higher in pastural and water habitats on organic farms than in the same habitats on conventional farms. Of the 18 insect families that are important components of the bat diet, 5 were significantly more abundant on organic farms overall. Some were also more abundant within organic pastural, woodland, and water habitats than on conventional farmland habitats. The activity of bats that mainly ate Lepidoptera was significantly correlated with the abundance of this order. Our observations suggest that agricultural intensification has a profound impact on nocturnal insect communities. Because bats are resource limited, a reduction in prey availability through agricultural intensification will adversely affect bat populations. Less‐intensive farming benefits British bat populations by providing and maintaining diverse and structurally varied habitats, which in turn support a wide selection of insect prey for bats, including insect families that are significant components of the diet of a number of rare bat species.
New Tools for Marine Conservation: the Leasing and Ownership of Submerged Lands
Authors: BECK MICHAEL W. , MARSH THERESA D. , REISEWITZ SHAUNA E. , BORTMAN MARCI L.
Published: September 2004

Abstract:  It has been assumed that strategies for estuarine and marine conservation must be substantially different than those for terrestrial conservation because the seas are all publicly owned. This is an unfortunate misconception. We explored the leasing and ownership of submerged lands as tools for marine conservation and provide examples of the implementation of these tools from The Nature Conservancy's work in Texas, Washington, and New York (U.S.A.). We found that the leasing and ownership of submerged lands are viable new tools for marine conservation. There is a significant amount of submerged land available for lease and ownership in the United States and other countries that includes a diverse array of ecosystems (e.g., kelp forests, marshes, seagrass meadows, oyster reefs, tidal flats, clam beds, scallop beds, sponge, and coral reefs). From our review of policy and experience in practice, we have identified some key benefits and considerations for the use of these tools. Conservation benefits for the leasing and ownership of submerged lands include opportunities to restore ecologically and economically important species, protect diversity in sanctuaries, draw on substantial terrestrial experience in leasing and ownership, buy land cheaply, develop ecologically sustainable harvest practices, partner with fishers and local communities to improve water quality, create control areas for research, and partake in local management forums as a direct stakeholder. Bivalve shellfish are particularly amenable to conservation with these tools because existing policy is well established for leasing and ownership rights to sessile animals that exist on the sea floor. Conservation buyers need to consider that community sentiment does not always favor private rights to submerged lands, conservation interest in submerged lands could affect prices, association with incompatible aquaculture practices will be detrimental, enforcement of restrictions can be difficult, and there may be concerns about setting the precedent of paying for conservation of submerged lands. Policy makers should be encouraged to include more opportunities for conservation and not just exploitation of natural resources on submerged land leases.
Effects of Desertification Caused by Lithophaga lithophaga (Mollusca) Fishery on Littoral Fish Assemblages along Rocky Coasts of Southeastern Italy
Authors: GUIDETTI PAOLO , FRASCHETTI SIMONETTA , TERLIZZI ANTONIO , BOERO FERDINANDO
Published: September 2004

Abstract:  We surveyed shallow, rocky reefs in southwestern Apulia (Mediterranean Sea) to assess the effects on coastal fish assemblages of the date mussel ( Lithophaga lithophaga) fishery, an illegal practice that strips the rocky reef bare. We visually sampled fish four times over 15 months at three locations, one affected by date‐mussel fishery and two controls. The fish assemblage at the affected location differed significantly from those at the control locations over all sampling times. Herbivorous fishes, sparids, and labrids (genus Symphodus) contributed most to the differences between the affected location and controls. Lower densities of Symphodus spp. were observed at the affected location, whereas detritivorous fishes were recorded exclusively at control sites. Small serranids and sparids showed temporal trends that differed between the affected location and the control locations. Our results suggest that the date‐mussel fishery affects fish assemblages chiefly through reduction of arborescent macroalgae (contributing to habitat complexity and primary production) and emphasize the need for more effective policing against this destructive practice.
Vascular endothelial growth factor (VEGF) and its receptor VEGFR‐2 in the regulation of corneal neovascularization and wound healing
Authors: Gan Lisha , Fagerholm Per , Palmblad Jan
Published: September 2004

Purpose:  To study the change in expression of vascular endothelial growth factor (VEGF) and its receptor VEGFR‐2 in the rabbit cornea and limbus following a penetrating, central corneal alkali burn. The influence of different cells on VEGF and VEGFR‐2 expression was studied by excluding granulocytes from the wound area.

Methods:  Fourteen New Zealand white rabbits were subjected to a penetrating, 5‐mm diameter, central corneal alkali burn in one eye under general anaesthesia. Seven of the rabbits were given injections of fucoidin for 36 hours. The rabbits were killed after 36 hours and the corneas were excised with a sclera rim and prepared for immunohistochemistry.

Results:  Both VEGF and VEGFR‐2 are strongly expressed in the frontline of repopulating epithelial, stromal and endothelial cells during wound healing, irrespective of granulocyte presence. Vascular endothelial cells express VEGF strongly after injury, but only in the presence of granulocytes.

Conclusion:  Corneal neovascularization requires the presence of granulocytes to stimulate vascular endothelial cells. During wound healing in this area, VEGF is a factor that stimulates proliferation and migration and that is not influenced by granulocytes.
Skin burn, bilateral iridocyclitis and amnesia following a lightning injury
Authors: Sommer Lone K. , Lund‐Andersen Henrik
Published: September 2004

Purpose:  To describe a case of lightning injury restricted to the eyes and facial skin.

Methods:  Case history describing the clinical examination of a 54‐year‐old woman.

Results:  Following a lightning stroke the patient suffered from a sharply demarcated facial skin burn and bilateral iridocyclitis with raised intraocular pressure. Initially she had amnesia regarding the incident. She recovered on symptomatic treatment, with dry eyes as the only sequela.

Conclusion:  We suggest that a lightning current travelled over the outside of the patient's body facilitated by her wet raincoat, a so‐called flash‐over. Thereby, she was spared from more severe injury, and only the exposed areas of the face and eyes were affected.
Position of anterior capsulorhexis and posterior capsule opacification
Authors: Wejde Gisela , Kugelberg Maria , Zetterström Charlotta
Published: September 2004

Purpose:  To evaluate whether the position of the anterior continuous curvilinear capsulorhexis influences the rate of posterior capsule opacification (PCO).

Methods:  A total of 119 patients, aged 61–86 years, underwent cataract surgery with phacoemulsification performed by a single surgeon. The patients were randomized to implantation with either a silicone intraocular lens (IOL) (SI40NB, Allergan) or an AcrySof IOL (MA60BM, Alcon). Three years after surgery, the rate of PCO was analysed using the evaluation of posterior capsule opacification computer software (EPCO). The results were related to the capsulorhexis position, which was assessed with a retroillumination photograph.

Results:  If the capsulorhexis was located partially or completely off the optics of the IOL, compared to totally on the IOL, significantly more PCO was found (p = 0.0014). When comparing within each IOL type, patients with AcrySof IOLs were found to have significantly less PCO when the capsulorhexis was totally on the optic (p = 0.0048). This difference was also significant in the silicone group (p = 0.041).

Conclusion:  A relatively small and central capsulorhexis allowing for the complete covering of the IOL optics by the rhexis edges seems to protect against PCO in cataract surgery, with both round‐edged silicone IOLs and sharp‐edged hydrophobic acrylic IOLs.
System Effects in Generic Risk-Based Inspection Planning
Authors: Straub Daniel , Faber Michael Havbro
Published: September 2004

Reliability and risk-based inspection planning (RBI) has been developed in the past for single structural details subject to fatigue, based on structural reliability analysis. This paper extends the methodology to systems with a stochastic dependency between the individual fatigue hot spots. It addresses the general decision theoretic problems that arise when dealing with RBI of systems. The differences to inspection planning for individual hot spots are listed and discussed. Using a generic format for single hot spots, a consistent approach to the problem is proposed, based on the concept of Value of Information. Possible applications of the methodology are outlined.
A Method for the Validation of Predictive Computations Using a Stochastic Approach
Authors: Pellissetti Manuel , Ghanem Roger
Published: September 2004

Stochastic finite element methods provide predictions of the behavior of mechanical systems with randomly fluctuating material properties. Limited data is typically available for the characterization of these properties, introducing errors in their representation. In the present paper, the sensitivity of the response predictions with respect to the stochastic properties is analyzed, by means of the direct differentiation method (DDM). Explicit expressions for the dependence of certain statistics of the response on the statistics of the material property are obtained. The response sensitivities are then used to estimate the error in the response predictions, caused by the error in the representation of the stochastic property. Numerical results for a simple Bernoulli beam are presented.
Vocal Fold Tissue Failure: Preliminary Data and Constitutive Modeling†
Authors: Chan Roger W.
Published: September 2004

In human voice production (phonation), linear small-amplitude vocal fold oscillation occurs only under restricted conditions. Physiologically, phonation more often involves large-amplitude oscillation associated with tissue stresses and strains beyond their linear viscoelastic limits, particularly in the lamina propria extracellular matrix (ECM). This study reports some preliminary measurements of tissue deformation and failure response of the vocal fold ECM under large-strain shear. The primary goal was to formulate and test a novel constitutive model for vocal fold tissue failure, based on a standard-linear cohesive-zone (SL-CZ) approach. Tissue specimens of the sheep vocal fold mucosa were subjected to torsional deformation in vitro, at constant strain rates corresponding to twist rates of 0.01, 0.1, and 1.0 rad/s. The vocal fold ECM demonstrated nonlinear stress-strain and rate-dependent failure response with a failure strain as low as 0.40 rad. A finite-element implementation of the SL-CZ model was capable of capturing the rate dependence in these preliminary data, demonstrating the model’s potential for describing tissue failure. Further studies with additional tissue specimens and model improvements are needed to better understand vocal fold tissue failure.
Branch Angle and Flow Into a Symmetric Bifurcation
Authors: Tadjfar Mehran
Published: September 2004

Arterial branches are found to be a major site for formation of arterial plaque. In this study, we investigate the role of the bifurcation angle on the flow into a symmetric bifurcation. Specially, how the changes in the bifurcation angle influences the distribution of axial wall shear in the bifurcation model. The flow in a range of branch opening half-angle of π/25⩽θ⩽π/4 are numerically simulated. The flow in the above models is calculated for the inlet flow Reynolds numbers of 250, 500, 1000, and 2000. It is found that at higher values of the opening angle of the bifurcation, the possibility and severity of flow separation at the appropriate wall location increases.
Benchmark Solution for the Prediction of Temperature Distributions During Radiofrequency Ablation of Cardiac Tissue
Authors: Roper and Ryan T. , Jones Matthew R.
Published: September 2004

Several studies on radiofrequency (RF) ablation are aimed at accurately predicting tissue temperature distributions by numerical solution of the bioheat equation. This paper describes the development of a solution that can serve as a benchmark for subsequent numerical solutions. The solution was obtained using integral transforms and evaluated using a C program. Temperature profiles were generated at various times and for different convection coefficients. In addition, a numerical model was developed using the same assumptions made in obtaining the benchmark solution. Comparison of surface and axial temperature profiles shows that the two solutions match very closely, cross validating the numerical methods used in evaluating both solutions.
Dependence of Calculus Retropulsion Dynamics on Fiber Size and Radiant Exposure During Ho:YAG Lithotripsy
Authors: Lee Ho , Ryan Robert T. , Kim Jeehyun , Choi Bernard , Arakeri Navanit V. , Teichman Joel M. H. , Welch A. J.
Published: September 2004

During pulsed laser lithotripsy, the calculus is subject to a strong recoil momentum which moves the calculus away from laser delivery and prolongs the operation. This study was designed to quantify the recoil momentum during Ho:YAG laser lithotripsy. The correlation among crater shape, debris trajectory, laser-induced bubble and recoil momentum was investigated. Calculus phantoms made from plaster of Paris were ablated with free running Ho:YAG lasers. The dynamics of recoil action of a calculus phantom was monitored by a high-speed video camera and the laser ablation craters were examined with Optical Coherent Tomography (OCT). Higher radiant exposure resulted in larger ablation volume (mass) which increased the recoil momentum. Smaller fibers produced narrow craters with a steep contoured geometry and decreased recoil momentum compared to larger fibers. In the presence of water, recoil motion of the phantom deviated from that of phantom in air. Under certain conditions, we observed the phantom rocking towards the fiber after the laser pulse. The shape of the crater is one of the major contributing factors to the diminished recoil momentum of smaller fibers. The re-entrance flow of water induced by the bubble collapse is considered to be the cause of the rocking of the phantom.
Magnetic Resonance Imaging Analysis of Right Ventricular Pressure-Volume Loops
Authors: Kuehne Titus , Yilmaz Sevim , Steendijk Paul , Moore Phillip , Groenink Maarten , Saaed Maythem , Weber Oliver , Higgins Charles B. , Ewert Peter , Fleck Eckard , Nagel Eike , Schulze-Neick Ingram , Lange Peter
Published: September 2004

Background—

The aims of this study were to validate MRI-derived right ventricular (RV) pressure-volume loops for assessment of RV myocardial contractility and then to apply this technique in patients with chronic RV pressure overload for assessment of myocardial contractility, ventricular pump function, and VA coupling.

Methods and Results—

Flow-directed catheters were guided under MR fluoroscopy (1.5 T) into the RV for invasive pressure measurements. Simultaneously, ventricular volumes and myocardial mass were assessed from cine MRI. From sampled data, RV pressure-volume loops were constructed, and maximal ventricular elastance indexed to myocardial mass (E
max_i
) was derived by use of a single-beat estimation method. This MRI method was first validated in vivo (6 swine), with conductance techniques used as reference. Bland-Altman test showed good agreement between methods (E
max_i
=5.1±0.5 versus 5.8±0.7 mm Hg · mL
−1
· 100 g
−1
, respectively;
P
=0.08). Subsequently, the MRI method was applied in 12 subjects: 6 control subjects and 6 patients with chronic RV pressure overload from pulmonary hypertension. In these patients, indexes of RV pump function (cardiac index), E
max_i
, and VA coupling (E
max
/E
a
) were assessed. In patients with pulmonary hypertension, RV pump function was decreased (cardiac index, 2.2±0.5 versus 2.9±0.4 L · min
−1
· m
−2
;
P
<0.01), myocardial contractility was enhanced (E
max_I
, 9.2±1.1 versus 5.0±0.9 mm Hg · mL
−1
· 100 g
−1
;
P
<0.01), and VA coupling was inefficient (E
max
/E
a
, 1.1±0.3 versus 1.9±0.4;
P
<0.01) compared with control subjects.

Conclusions—

RV myocardial contractility can be determined from MRI-derived pressure-volume loops. Chronic RV pressure overload was associated with reduced RV pump function despite enhanced RV myocardial contractility. The proposed MRI approach is a promising tool to assess RV contractility in the clinical setting.
Cytokine-Induced Mobilization of Circulating Endothelial Progenitor Cells Enhances Repair of Injured Arteries
Authors: Kong Deling , Melo Luis G. , Gnecchi Massimiliano , Zhang Lunan , Mostoslavsky Gustavo , Liew Chong C. , Pratt Richard E. , Dzau Victor J.
Published: September 2004

Background—

The existence of circulating endothelial progenitor cells (CEPCs) has previously been documented. These cells can be mobilized by cytokines and are recruited to sites of injury, where they may participate in tissue repair. In the present study, we examined the hypothesis that mobilization of CEPCs by exogenous granulocyte-colony stimulating factor (G-CSF) enhances repair of injured arteries by facilitating reendothelialization and inhibiting neointima development.

Methods and Results—

Male rats were injected daily with 50 μg/kg recombinant human G-CSF or 0.9% NaCl SC for 8 days. On the fifth day of treatment, 1 mL of blood was collected for fluorescence-activated cell sorting analysis of mononuclear cells, and the animals underwent balloon angioplasty of the common carotid artery. The animals were killed at 2 or 4 weeks after injury, and the carotid arteries were harvested and processed for immunohistochemistry, scanning electron microscopy (SEM), and morphometric analysis of endothelialization and neointimal formation. G-CSF increased the number of circulating mononuclear cells that express endothelial cell lineage markers several-fold. SEM and immunohistochemical staining with the endothelial marker, platelet and endothelial cell adhesion molecule-1, showed rapid and nearly complete (>90%) reendothelialization of the denuded vessels in the G-CSF–treated animals compared with <20% in the control animals. Reendothelialization was paralleled by a decrease in inflammation in the vessel wall. Neointima thickness was reduced by ≈60% in the G-CSF–treated animals compared with control animals at 2 and 4 weeks after injury.

Conclusion—

We postulate that cytokine-induced mobilization of CEPCs may be a suitable therapeutic strategy for prevention of restenosis after revascularization procedures.
Recombinant Human Antibodies Against Aldehyde-Modified Apolipoprotein B-100 Peptide Sequences Inhibit Atherosclerosis
Authors: Schiopu Alexandru , Bengtsson Jenny , Söderberg Ingrid , Janciauskiene Sabina , Lindgren Stefan , Ares Mikko P.S. , Shah Prediman K. , Carlsson Roland , Nilsson Jan , Fredrikson Gunilla Nordin
Published: September 2004

Background—

Accumulation and oxidation of LDL are believed to be important initiating factors in atherosclerosis. Oxidized LDL is recognized by the immune system, and animal studies have suggested that these immune responses have a protective effect against atherosclerosis. Aldehyde-modified peptide sequences in apolipoprotein B-100 (apoB-100) are major targets for these immune responses.

Methods and Results—

Human IgG1 antibodies against 2 malondialdehyde (MDA)-modified apoB-100 peptide sequences were produced through screening of a single-chain antibody-fragment library and subsequent cloning into a pcDNA3 vector. Three weekly doses of these antibodies were injected into male apoE
−/−
mice. Phosphate-buffered saline and human IgG1 antibodies against fluorescein isothiocyanate were used as controls. One of the IgG1 antibodies significantly and dose-dependently reduced the extent of atherosclerosis as well as the plaque content of oxidized LDL epitopes and macrophages. In cell culture studies, human monocytes were incubated with native LDL or oxidized LDL, in the presence of antibodies. The same antibody induced an increase in monocyte binding and uptake of oxidized LDL.

Conclusions—

These findings suggest that antibodies are important mediators of atheroprotective immune responses directed to oxidized LDL. Thus, passive immunization against MDA-modified apoB-100 peptide sequences may represent a novel therapeutic approach for prevention and treatment of cardiovascular disease.
Usefulness of Exercise Testing in the Prediction of Coronary Disease Risk Among Asymptomatic Persons as a Function of the Framingham Risk Score
Authors: Balady Gary J. , Larson Martin G. , Vasan Ramachandran S. , Leip Eric P. , O’Donnell Christopher J. , Levy Daniel
Published: September 2004

Background—

The purpose of this study is to determine the usefulness of exercise treadmill testing (ETT) among asymptomatic persons in predicting coronary heart disease (CHD) events over and above the Framingham CHD risk score.

Methods and Results—

Subjects included 3043 members of the Framingham Heart Study offspring cohort without CHD (1431 men and 1612 women; age, 45±9 years) who underwent ETT and were followed up for 18.2 years. The risk of developing CHD was evaluated relative to 3 exercise test variables: (1) ST-segment depression ≥1 mm, (2) failure to achieve target heart rate (THR) of 85% predicted maximum, and (3) exercise capacity. In multivariable analyses that adjusted for age and Framingham CHD risk score, among men, ST-segment depression (hazard ratio [HR], 1.88; 95% CI, 1.21 to 2.91) and failure to achieve THR (HR, 1.70; 95% CI, 1.18 to 2.45) predicted higher CHD risk, whereas a greater exercise capacity predicted lower CHD risk (HR per MET, 0.94; 95% CI, 0.89 to 0.99). Although similar HRs were seen in women, those results were not statistically significant. Among men with 10-year predicted risk ≥20%, failure to reach THR and ST-segment depression both more than doubled the risk of an event (HR, 2.66 and HR, 2.11, respectively), and each MET increment in exercise capacity reduced risk by 13% (HR, 0.87).

Conclusions—

Among asymptomatic men, ST-segment depression, failure to reach THR, and exercise capacity during ETT provided additional prognostic information in age- and Framingham risk score–adjusted models, particularly among those in the highest risk group (10-year predicted CHD risk of ≥20%). The evaluation of exercise test variables in women is limited, given our sample size and the few CHD events in women.
Plaque Neovascularization Is Increased in Ruptured Atherosclerotic Lesions of Human Aorta
Authors: Moreno Pedro R. , Purushothaman K. Raman , Fuster Valentin , Echeverri Dario , Truszczynska Helena , Sharma Samin K. , Badimon Juan J. , O’Connor William N.
Published: September 2004

Background—

Growth of atherosclerotic plaques is accompanied by neovascularization from vasa vasorum microvessels extending through the tunica media into the base of the plaque and by lumen-derived microvessels through the fibrous cap. Microvessels are associated with plaque hemorrhage and may play a role in plaque rupture. Accordingly, we tested this hypothesis by investigating whether microvessels in the tunica media, the base of the plaque, and the fibrous cap are increased in ruptured atherosclerotic plaques in human aorta.

Methods and Results—

Microvessels, defined as CD34-positive tubuloluminal capillaries recognized in cross-sectional and longitudinal profiles, were quantified in 269 advanced human plaques by bicolor immunohistochemistry. Macrophages/T lymphocytes and smooth muscle cells were defined as CD68/CD3-positive and α-actin–positive cells. Total microvessel density was increased in ruptured plaques when compared with nonruptured plaques (
P
=0.0001). Furthermore, microvessel density was increased in lesions with severe macrophage infiltration at the fibrous cap (
P
=0.0001) and at the shoulders of the plaque (
P
=0.0001). In addition, microvessel density was also increased in lesions with intraplaque hemorrhage (
P
=0.04) and in thin-cap fibroatheromas (
P
=0.038). Logistic regression analysis identified plaque base microvessel density (
P
=0.003) as an independent correlate to plaque rupture.

Conclusions—

Thus, neovascularization as manifested by the localized appearance of microvessels is increased in ruptured plaques in the human aorta. Furthermore, microvessel density is increased in lesions with inflammation, with intraplaque hemorrhage, and in thin-cap fibroatheromas. Microvessels at the base of the plaque are independently correlated with plaque rupture, suggesting a contributory role for neovascularization in the process of plaque rupture.
Sphingosine Kinase Activation Mediates Ischemic Preconditioning in Murine Heart
Authors: Jin Zhu-Qiu , Goetzl Edward J. , Karliner Joel S.
Published: September 2004

Background—

Phosphorylation of sphingosine by sphingosine kinase (SK) is the rate-limiting step in the cellular synthesis of sphingosine 1-phosphate (S1P). The monoganglioside GM
1
, which stimulates SK, is cardioprotective in part through increased generation of S1P that protects myocytes by diverse mechanisms. Because protein kinase C (PKC)ε activation is necessary for myocardial ischemic preconditioning (IPC) and PKC activators increase SK activity, we tested the hypothesis that SK may be a central mediator of IPC.

Methods and Results—

In adult murine hearts, IPC sufficient to reduce infarct size significantly increased cardiac SK activity, induced translocation of SK protein from the cytosol to membranes, and enhanced cardiac myocyte survival. IPC did not increase SK activity in PKCε-null mice. The SK antagonist
N,N
-dimethylsphingosine inhibited PKCε activation and directly abolished the protective effects of IPC and the enhanced SK activity induced by IPC.

Conclusions—

These findings demonstrate that PKCε is thus recruited by IPC and induces activation of SK that then mediates IPC-induced cardioprotection in murine heart.