bluuebunny/crossref_metadata_2025 huggingface dataset:
Protective effect of noninherited maternal HLA-DR antigens on rheumatoid arthritis development
Authors: Feitsma Anouk L. , Worthington Jane , van der Helm-van Mil Annette H. M. , Plant Darren , Thomson Wendy , Ursum Jennie , van Schaardenburg Dirkjan , van der Horst-Bruinsma Irene E. , van Rood Jon J. , Huizinga Tom W. J. , Toes René E. M. , de Vries René R. P.
Published: December 2007

Rheumatoid arthritis (RA) is a complex genetic disorder in which the HLA-region contributes most to the genetic risk. HLA-DRB1-molecules containing the amino acid sequence DERAA (i.e., HLA-DRB1*0103, *0402, *1102, *1103, *1301, *1302, and *1304) are associated with protection from RA. It has been proposed that not only inherited but also noninherited HLA-antigens from the mother (NIMA) can influence RA-susceptibility. Up to now, no protective NIMAs were described. Here, we studied whether DERAA-containing HLA-DRB1-alleles as NIMA are associated with a protective effect. One hundred seventy-nine families were studied, 88 from the Netherlands and 91 from the United Kingdom. The frequency of DERAA-containing HLA-DRB1-alleles of the Dutch mothers (16.1%), but not of the fathers (26.2%), was lower compared with the general Dutch population (29.3%;
P
= 0.02). This was replicated in the English set of patients and controls (
P
= 0.01). Further, of all families, 45 contained at least one DERAA-negative child with RA and at least one DERAA-positive parent. The odds for the DERAA-negative RA patients of having a DERAA-positive mother was significantly lower compared with having a DERAA-positive father (OR 0.25;
P
= 0.003). These data show a protective NIMA-effect in a human autoimmune disease and indicate that a DERAA-positive mother can transfer protection against RA to her DERAA-negative child.
The preleukemic state of mice reconstituted with Mixl1-transduced marrow cells
Authors: Metcalf Donald , Glaser Stefan , Mifsud Sandra , Di Rago Ladina , Robb Lorraine
Published: December 2007

Murine granulocytic cells, in becoming leukemic, need to acquire enhanced self-generation and a capacity for autocrine growth stimulation. Mice transplanted with bone marrow cells transduced with the Mixl1 homeobox gene develop a very high frequency of myeloid leukemia derived from the transduced cells. Preleukemic mice contained a high frequency of transduced clonogenic granulocytic cells. They exhibited an abnormally high capacity for self-replication and could generate immortalized granulocytic cell lines that remained absolutely dependent on either GM-CSF or IL-3 and were not leukemic. Organs from mice repopulated by marrow cells transduced either with Mixl1 or the control murine stem cell virus vector exhibited a capacity to produce IL-3
in vitro
, activity being highest with the lungs, marrow, bladder, and thymus. Supporting evidence for the
in vivo
production of IL-3 was the frequent development of mast cells in the marrow. Overexpression of Mixl1 appears capable of inducing an abnormal self-renewal capacity in granulocytic precursors. Aberrant production of IL-3 was not present in the continuous Mixl cell lines and was therefore not in itself likely to be a leukemogenic change but it could support the enhanced survival and proliferation of the Mixl1 granulocytic populations until a final leukemogenic mutation occurs in them.
Bronchial smooth muscle remodeling involves calcium-dependent enhanced mitochondrial biogenesis in asthma
Authors: Trian Thomas , Benard Giovanni , Begueret Hugues , Rossignol Rodrigue , Girodet Pierre-Olivier , Ghosh Debajyoti , Ousova Olga , Vernejoux Jean-Marc , Marthan Roger , Tunon-de-Lara José-Manuel , Berger Patrick
Published: December 2007

Asthma and chronic obstructive pulmonary disease (COPD) are characterized by different patterns of airway remodeling, which all include an increased mass of bronchial smooth muscle (BSM). A remaining major question concerns the mechanisms underlying such a remodeling of BSM. Because mitochondria play a major role in both cell proliferation and apoptosis, we hypothesized that mitochondrial activation in BSM could play a role in this remodeling. We describe that both the mitochondrial mass and oxygen consumption were higher in the BSM from asthmatic subjects than in that from both COPD and controls. This feature, which is specific to asthma, was related to an enhanced mitochondrial biogenesis through up-regulation of peroxisome proliferator-activated receptor γ coactivator (PGC)–1α, nuclear respiratory factor-1, and mitochondrial transcription factor A. The priming event of such activation was an alteration in BSM calcium homeostasis. BSM cell apoptosis was not different in the three groups of subjects. Asthmatic BSM was, however, characterized by increased cell growth and proliferation. Both characteristics were completely abrogated in mitochondria-deficient asthmatic BSM cells. Conversely, in both COPD and control BSM cells, induction of mitochondrial biogenesis reproduced these characteristics. Thus, BSM in asthmatic patients is characterized by an altered calcium homeostasis that increases mitochondrial biogenesis, which, in turn, enhances cell proliferation, leading to airway remodeling.
Seed growth suppression constrains the growth of seed parasites: premature acorn abscission reduces Curculio elephas larval size
Authors: BONAL RAÚL , MUÑOZ ALBERTO
Published: December 2007

Abstract 1. The abscission of seeds infested by insects is common in many plants and has been proposed as a defensive mechanism, although its negative consequences for insects have rarely been assessed.

2. We assessed the consequences of seed abscission studying the interactions between the holm oak Quercus ilex and the chestnut weevil Curculio elephas, its main pre‐dispersal seed predator. Female weevils oviposit into the acorns and the larvae must complete their development inside a single acorn feeding on the cotyledons. The growth of the infested acorns is suppressed because they are prematurely abscised.

3. Female weevils oviposit along the acorn growing period; hence, the size of the infested acorns increased with date. The growth of the larvae inside the smaller, early infested, acorns was constrained because food (i.e. cotyledons) was frequently depleted. Larval size increased with the date along with the size of the infested acorns, but it declined slightly in the latest dates as a result of the higher conspecific competition provoked by the larger number of larvae per acorn.

4. The present results demonstrate that premature seed abscission by Q. ilex had negative consequences for C. elephas, as a smaller acorn size reduced food availability and constrained larval size, a key insect life history trait. At the same time, it is suggested that the growth suppression of infested acorns may condition the oviposition phenology of these insects according to their body size. These results need to be considered in further research in the context of the evolutionary significance of premature seed abscission as a defensive mechanism.
Seismic characterization of basalt flows from the Faroes margin and the Faroe‐Shetland basin
Authors: Spitzer Roman , White Robert S. , Christie Philip A.F. ,   the iSIMM Team
Published: December 2007

High‐quality seismic profiles across the Faroes volcanic continental margin and the adjacent continental shelf show contrasting styles of basalt emplacement across two major structural boundaries. At the rifted continental margin, the basalts form prominent seaward dipping reflector sequences up to 5 km thick. The same basalts, after they had travelled in a landward direction across the elevated, subaerial Faroes shelf, produced prominent landward dipping foresets, where they flowed across the paleo‐coastline into the deep water of the Faroe‐Shetland Basin. In both cases we are able to image details of the internal structure of the basalts as a result of using a low‐frequency airgun source capable of penetrating through the basalt sequence, together with long‐offset recordings from ocean bottom seismometers and a 12 km long, deep‐towed, hydrophone streamer.
Clinical long‐term evaluation of MTA as a direct pulp capping material in primary teeth
Authors: Tuna D. , Ölmez A.
Published: December 2007

Aim  To evaluate the effectiveness of mineral trioxide aggregate (MTA) when used as a pulp capping material in primary teeth.

Methodology  Clinical follow‐up was performed on 25 symmetrical pairs of primary molars with deep occlusal caries, in 25 patients between the ages of 5 and 8 years. Pulps exposed during cavity preparation were treated by direct pulp capping with MTA or calcium hydroxide, based with resin‐bonded zinc oxide eugenol cement and restored with amalgam. Clinical and radiographic examinations were carried out at 1, 3, 6, 9, 12, 18 and 24 months.

Results  Twenty‐four‐month clinical and radiographic follow‐ups were carried out on 22 patients. One patient failed to return for evaluation after 1 month, one after 9 months and another after 12 months. During follow‐up, none of the MTA and calcium hydroxide groups exhibited clinical or radiographic failure.

Conclusions  Mineral trioxide aggregate was found to be as successful as calcium hydroxide when used for direct pulp capping in primary teeth. Further histological investigations are needed to support these findings.
Haemoglobin‐vesicles as artificial oxygen carriers: present situation and future visions
Authors: Sakai H. , Sou K. , Horinouchi H. , Kobayashi K. , Tsuchida E.
Published: December 2007

During the long history of development of haemoglobin (Hb)‐based O2 carriers (HBOCs), many side effects of Hb molecules have become apparent. They imply the physiological importance of the cellular structure of red blood cells. Hb‐vesicles (HbV) are artificial O2 carriers that encapsulate concentrated Hb solution with a thin lipid membrane. We have overcome the intrinsic issues of the suspension of HbV as a molecular assembly, such as stability for storage and in blood circulation, blood compatibility and prompt degradation in the reticuloendothelial system. Animal tests clarified the efficacy of HbV as a transfusion alternative and the possibility for other clinical applications. The results of ongoing HbV research make us confident in advancing further development of HbV, with the expectation of its eventual realization.
A highly reliable and budget‐friendly Peltier‐cooled camera for biological fluorescence imaging microscopy
Authors: JOLLING KOEN , VANDEVEN MARTIN , VAN DEN EYNDEN JIMMY , AMELOOT MARCEL , VAN KERKHOVE EMMY
Published: December 2007

The SAC8.5, a low‐cost Peltier‐cooled black and white 8‐bit CCD camera for astronomy, was evaluated for its use in imaging microscopy. Two camera–microscope configurations were used: an epifluorescence microscope (Nikon Eclipse TE2000‐U) and a bottom port laser scanning confocal microscope system (Zeiss LSCM 510 META). Main advantages of the CCD camera over the currently used photomultiplier detection in the scanning setup are fast image capturing, stable background, an improved signal‐to‐noise ratio and good linearity. Based on DAPI‐labelled Chinese Hamster Ovarian cells, the signal‐to‐noise ratio was estimated to be 4 times higher with respect to the currently used confocal photomultiplier detector. A linear relationship between the fluorescence signal and the FITC‐inulin concentrations ranging from 0.05 to 1.8 mg mL−1 could be established. With the SAC8.5 CCD camera and using DAPI, calcein‐AM and propidium iodide we could also distinguish between viable, apoptotic and necrotic cells: exposure to CdCl2 caused necrosis in A6 cells. Additional examples include the observation of wire‐like mitochondrial networks in Mito Tracker Green‐loaded Madin–Darby canine kidney cells. Furthermore, it is straightforward to interface the SAC8.5 with automated shutters to prevent rapid fluorophore photobleaching via easy to use astrovideo software. In this study, we demonstrate that the SAC8.5 black and white CCD camera is an easy‐to‐implement and cost‐conscious addition to quantitative fluorescence microfluorimetry on living tissues and is suitable for teaching laboratories.
Contribution of immunodiagnostic tests to epidemiological/intervention studies of cysticercosis/taeniosis in México
Authors: FLISSER A. , GYORKOS T. W.
Published: December 2007

Cysticercosis is acquired when swine ingest human faeces contaminated with Taenia solium eggs. Humans become tapeworm carriers when they ingest infected pork meat. They can also develop cysticercosis after inadvertently swallowing T. solium eggs. Human neurocysticercosis (NCC) is considered as a public health problem in México and in several countries around the world, mainly developing ones. The development of immunodiagnostic techniques has promoted the conduct of seroepidemiological studies. This review provides insight into the evolution of these techniques, their predictive values and their use in field studies, and summarizes evidence supporting health care practice and policy related to cysticercosis/taeniosis in México. Serological studies in rural and urban settings have demonstrated that close proximity with a tapeworm carrier is the main risk factor for acquiring cysticercosis. Research focusing on the tapeworm carrier generated an ELISA for the detection of Taenia coproantigens and facilitated the evaluation of intervention measures. Health education and self‐identification of tapeworm carriers were shown to be successful. However, cestodial treatment as a community‐based intervention was not as successful. Current immunodiagnostic techniques can be used to pinpoint transmission foci so that appropriate and effective interventions can be applied. In this way, sustainable control, and even eradication of T. solium may be envisioned.
Detection and Localization of Naturally Transmitted Avian Leukosis Subgroup J Virus in Egg‐type Chickens by In situ PCR Hybridization
Authors: Li N. , Xu B. , Dong W. , Qiao S. , Lee L. F. , Zhang H. M. , Li M. , Du N.
Published: December 2007

Avian leukosis virus (ALV) subgroup J (ALV‐J) is an exogenous ALV and causes myeloid leukosis in meat‐type chickens. We have previously reported the isolation and identification of ALV‐J in commercial layer flocks from 12 farms in northern China. In this report, we further characterized this virus by in situ polymerase chain reaction (PCR) hybridization in various affected organs of chickens from six of the 12 farms. A routine method for hybridization of nucleic acid uses radioactive probe, such as a P32‐labelled probe. We found that the non‐radioactive digoxigenin (DIG) probe is sensitive enough to detect the nucleic acid of virus in chicken tissues. We used a pair of published primers (H5/H7) specific to the gp85 envelope gene and 3′ region of pol gene of prototype ALV‐J strain HPRS‐103. The total RNA extracted from tumour, bone marrow, oviduct, liver and spleen of the diseased chickens from six commercial flocks, and cDNA was successfully amplified. Using the primers and cDNA, we obtained an ALV‐J‐specific cDNA probe of 545 bp in length by PCR. In situ PCR with H5/H7 primers was carried out in the paraffin sections from tissues of the diseased chickens, followed by in situ hybridization using the DIG‐labelled cDNA probe. Positive hybridization signals were detected in the cytoplasm of paraffin sections of tumours and other organ tissues. The intensity of the signals was documented using an image analysis system measuring integral optical density (IOD). The IOD values for tissue sections treated by in situ PCR hybridization are significantly higher than that by in situ hybridization alone (P < 0.01). These data taken together suggest that in situ PCR hybridization is a more sensitive technique for detection of ALV‐J in tissue sections.
Anti‐endothelial cell antibodies in antineutrophil cytoplasmic antibodies negative pauci‐immune crescentic glomerulonephritis
Authors: CONG MIN , CHEN MIN , ZHANG JUN‐JUN , HU ZHAO , ZHAO MING‐HUI
Published: December 2007

Aim:  Pauci‐immune crescentic glomerulonephritis (CrGN) is frequently associated with circulating anti‐neutrophil cytoplasmic antibodies (ANCA). However, in patients with ANCA‐negative pauci‐immune CrGN, the pathogenesis is not clear. Anti‐endothelial cell antibodies (AECA) have been implicated in the pathogenesis of vasculitis. The purpose of this study is to investigate the prevalence of AECA and their possible clinical significance in ANCA‐negative pauci‐immune CrGN.

Methods:  Sera from 19 patients with ANCA‐negative pauci‐immune CrGN, 26 patients with ANCA‐positive pauci‐immune CrGN and 10 healthy blood donors were collected. Soluble proteins extracted from cultured human umbilical vein endothelial cells were used as antigens and western blot analysis was carried out to detect AECA.

Results:  In ANCA‐negative pauci‐immune CrGN, 10 of 19 patients were serum IgG‐AECA positive and seven bands reactive with endothelial antigens could be blotted. The prevalence of skin rash and thrombocytosis was significantly higher in patients with anti‐76 kDa and anti‐123 kDa autoantibodies than in patients without, respectively. Birmingham Vasculitis Activity Scores of patients with anti‐200 kDa AECA were significantly higher than in patients without. In the sera of 26 ANCA‐positive cases, 23 were AECA positive and 11 bands could be recognized. The prevalence of total AECA and anti‐90 kDa AECA was significantly lower in patients with ANCA‐negative pauci‐immune CrGN than in patients with ANCA‐positive pauci‐immune CrGN.

Conclusion:  Anti‐endothelial cell antibodies could be found in sera of patients with ANCA‐negative pauci‐immune CrGN; some AECA might have some clinical significance. The discrepancies of AECA might be a possible contributor to the differences between ANCA‐negative and ANCA‐positive pauci‐immune CrGN.
Leukaemia inhibitory factor is over‐expressed by ischaemic brain tissue concomitant with reduced plasma expression following acute stroke
Authors: Slevin M. , Krupinski J. , Mitsios N. , Perikleous C. , Cuadrado E. , Montaner J. , Sanfeliu C. , Luque A. , Kumar S. , Kumar P. , Gaffney J.
Published: December 2007

Leukaemia inhibitory factor (LIF) is a glycoprotein of the interleukin‐6 family, which has potent pro‐inflammatory properties and is involved in regulation of neuronal differentiation. We have previously identified its upregulation in gene microarrays following acute ischaemic stroke in man. LIF expression and localization was measured in human ischaemic stroke autopsy specimens, in a rat model of middle cerebral artery occlusion (MCAO) and in human foetal neural cell cultures following oxygen‐glucose deprivation (OGD) by Western blotting and immunohistochemistry. Circulating LIF was determined in the plasma of patients in the hyper‐acute stroke phase using a multiplex enzyme‐linked‐immunosorbent serologic assay system. Patients demonstrated an increase in LIF expression in peri‐infarcted regions with localization in neurons and endothelial cells of microvessels surrounding the infarcted core. The rat MCAO model showed similar upregulation in neurons with a peak increase at 90 min. Circulating serum LIF expression was significantly decreased in the hyper‐acute phase of stroke. Brain‐derived neurons and glia cultured in vitro demonstrated an increase in gene/protein and protein expression respectively following exposure to OGD. Increased LIF expression in peri‐infarcted regions and sequestration from the peripheral circulation in acute stroke patients characteristic of the pathobiological response to ischaemia and tissue damage.
The use of clinical findings in the identification of equine peritonitis cases that respond favorably to medical therapy
Authors: Southwood Louise L. , Russell Gail
Published: December 2007

Objective: To compare clinical findings in horses/foals with peritonitis that: (1) had no concurrent (NCA) versus a concurrent abnormality found during hospitalization, (2) survived to discharge versus did not survive to discharge, and (3) survived to discharge without surgery versus did not survive to discharge without surgery.

Design: Retrospective study.

Setting: George D. Widener Hospital for Large Animals at New Bolton Center.

Animals: Horses/foals admitted between 1992 and 2002 with a diagnosis of peritonitis. A diagnosis of peritonitis within 4 days of presentation and peritoneal fluid nucleated cell count >10,000/μL were required for study inclusion. Horses/foals were excluded if the peritonitis was secondary to gastrointestinal or reproductive tract perforation, a complication of exploratory celiotomy, or if peritonitis was not diagnosed until surgery or necropsy.

Interventions: None.

Measurements and main results: Information obtained from the medical records included clinical findings at presentation and during the initial 4 days of hospitalization. Outcome was defined as: (1) NCA (yes/no), (2) survived to discharge (yes/no), and (3) survived to discharge without surgery (yes/no). Forty‐two percent (23/55) of horses/foals had NCA; 78% (43/55) survived to discharge, and 68% (36/55) survived to discharge without surgery. Horses/foals with peritonitis that had any one of the following clinical findings were likely to survive to discharge without surgery: no signs of abdominal pain, normal/improved rectal temperature, normal/improved intestinal borborygmi, normal fecal production, no abnormal findings on abdominal palpation per rectum, no nasogastric reflux, or yellow/orange peritoneal fluid.

Conclusion: Clinical findings can be used to identify equine peritonitis cases that will respond favorably to medical therapy.
Left Atrial Volume Is Associated with Inflammation and Atherosclerosis in Patients with Kidney Disease
Authors: Rao Anupama K. , Djamali Arjang , Korcarz Claudia E. , Aeschlimann Susan E. , Wolff Matthew R. , Stein James H.
Published: December 2007

Background: Left atrial volume (LAV) is an independent echocardiographic predictor of cardiovascular events in the general population. We evaluated predictors of LAV in patients with advanced chronic kidney disease (CKD). Hypothesis: Increasing LAV identifies increased cardiovascular risk in patients with CKD. Methods: Transthoracic echocardiography was performed in CKD patients undergoing cardiovascular evaluation prior to listing for renal transplantation. LAV was measured using the biplane area‐length formula and indexed for body surface area. Carotid intima‐media thickness was assessed by B‐mode ultrasound. Lipoproteins were measured by nuclear magnetic resonance spectroscopy. Values are presented as mean (standard deviation). Relationships with LAV were evaluated using univariate and multivariable regression analyses. Results: There were 99 participants (80% white, 68% male). Their mean age was 55.7 (9.3) years. Significant correlates of LAV were systolic blood pressure (r = 0.24), C‐reactive protein (r = 0.29), carotid intima‐media thickness (r = 0.29), peak transmitral E‐wave (r = 0.38), and severity of mitral regurgitation (r = 0.23, P < 0.05 for all). LAV also was higher among individuals with a history of stroke (45 mL/m2 vs 36.3 mL/m2, P = 0.04) and with >75% stenosis on coronary angiography (38.4 mL/m2 vs 31.8 mL/m2, P = 0.03). In regression models, high sensitivity CRP (hs‐CRP), the transmitral E‐wave velocity, and a history of stroke independently predicted LAV (P ≤ 0.05). Conclusion: In individuals with advanced CKD, LAV is associated with inflammation, increased early transmitral filling velocities, and atherosclerosis. These findings may indicate increased cardiovascular risk with increasing LAV in patients with CKD.
Effect of Chronic Cocaine Abuse on the Elastic Properties of Aorta
Authors: Bigi Mohammad Ali Babaee , Aslani Amir , Mehrpour Maziar
Published: December 2007

Background: Any unfavorable effect of cocaine on aortic elastic properties will contribute to the adverse effects of cocaine on the cardiovascular system. Objectives: The aim of this study was to evaluate the aortic elastic properties in long‐term crack cocaine abusers. Methods: Twenty‐eight consecutive chronic cocaine abusers and 36 control subjects with similar age, gender, cholesterol, and triglyceride plasma levels, as well as incidence of cigarette smoking, hypertension, and diabetes mellitus were enrolled in the study. Results: The average duration of cocaine abuse was 10 ± 3.2 years. Diastolic thoracic aortic diameter was increased in cocaine users compared with control subjects (P < 0.05). Aortic strain and distensibility were approximately twofold lower and aortic stiffness index approximately threefold higher in patients compared with control subjects (P < 0.01). The duration of cocaine abuse was related to low aortic strain and distensibility as well as increased aortic stiffness index (R =−0.32, R =−0.38, and R = 0.28, respectively, weighted for age; P < 0.01). When the cocaine abusers were divided into quartiles of duration of cocaine using (first quartile: <5 years; second quartile: >5 and <8 years; third quartile: >8 and <11 years; and fourth quartile: >11 years), progressive increase was found in aortic stiffness index. Conclusion: The present study demonstrates that chronic cocaine abuse clearly produces significant decrease in the elastic properties of aorta. This effect of cocaine is related to the duration of cocaine abuse.
Segmental Early Relaxation Phenomenon as Determined by Tissue Doppler Imaging
Authors: Zhang Haibin , Song Yan , Zhu Yongsheng , Li Hongling , Zhu Ting , Qian Yunqiu , Liu Liwen , Zhang Jun , Zhou Xiaodong , Zhu Miaozhang
Published: December 2007

Background: The early diastolic peak velocity of left ventricular (LV) wall segment has always been thought to appear in the rapid filling phase. However, we find a segmental early relaxation phenomenon (SERP), characterized by an early diastolic peak velocity lying in the isovolumic relaxation (IVR) period. The present study aimed to investigate the characteristics of SERP segments with tissue Doppler imaging (TDI) echocardiography. Methods: TDI was performed in 119 patients with known or suspected coronary heart disease (CHD) and 60 normal subjects. The segmental early diastolic velocity pattern was classified as normal pattern (NP), postsystolic shortening (PSS) and SERP. Results: Segmental early diastolic velocity pattern was significantly associated with actual coronary diameter stenosis, relative coronary stenosis, wall motion score, and segmental location in LV wall. Compared with other segments, SERP segments had a higher IVR velocity and lower early diastolic peak velocity. Conclusion: SERP most frequently occurs in the distribution of artery with the relatively mildest stenosis, and is more likely accompanied by simultaneous PSS elsewhere in LV wall, which occurs most frequently in the distribution of artery with the relatively most severe stenosis. A decreased early diastolic peak velocity of SERP segment dose not necessarily mean impaired myocardial relaxation.
Delayed Manifestation of a Mid‐Esophageal Tear with Profuse Hemorrhage after Transesophageal Echocardiogram
Authors: Arora Sandeep , Chakravarthy Mithun , Srinivasan Venkatraman
Published: December 2007

Esophageal injury or perforation is a rare but life threatening complication of transesophageal echocardiogram (TEE). Most of the patients manifest symptoms within 24 hours of the procedure and upper esophagus is the most common site of injury. We report a patient who underwent TEE for the evaluation of severe valvular insufficiency and 4 days after the procedure developed an esophageal tear in its mid portion associated with profuse upper gastrointestinal bleeding. Though delayed esophageal perforation in the lower segment has been previously reported after a perioperative TEE, no such report exists to our knowledge, in the setting of a nonsurgical TEE.
Rapid growth of malignant melanoma in pregnancy
Authors: Sato Tomotaka , Ishiko Akira , Saito Masataka , Tanaka Masaru , Ishimoto Hitoshi , Amagai Masayuki
Published: December 2007

Malignant melanoma during pregnancy is a difficult problem as a variety of risks to both the mother and fetus must be weighed. We describe a rapidly progressive malignant melanoma diagnosed during pregnancy. There are no standarized guidelines for treatment; each case requires an individualized approach. We review the literature and present an algorithm to aid in approaching such patients.
Coupled Motions Under Compressive Load in Intact and ACL-Deficient Knees: A Cadaveric Study
Authors: Liu-Barba David , Hull M. L. , Howell S. M.
Published: December 2007

Knowledge of the coupled motions, which develop under compressive loading of the knee, is useful to determine which degrees of freedom should be included in the study of tibiofemoral contact and also to understand the role of the anterior cruciate ligament (ACL) in coupled motions. The objectives of this study were to measure the coupled motions of the intact knee and ACL-deficient knee under compression and to compare the coupled motions of the ACL-deficient knee with those of the intact knee. Ten intact cadaveric knees were tested by applying a 1600N compressive load and measuring coupled internal-external and varus-valgus rotations and anterior-posterior and medial-lateral translations at 0deg, 15deg, and 30deg of flexion. Compressive loads were applied along the functional axis of axial rotation, which coincides approximately with the mechanical axis of the tibia. The ACL was excised and the knees were tested again. In the intact knee, the peak coupled motions were 3.8deg internal rotation at 0deg flexion changing to −4.9deg external rotation at 30deg of flexion, 1.4deg of varus rotation at 0deg flexion changing to −1.9deg valgus rotation at 30deg of flexion, 1.4mm of medial translation at 0deg flexion increasing to 2.3mm at 30deg of flexion, and 5.3mm of anterior translation at 0deg flexion increasing to 10.2mm at 30deg of flexion. All changes in the peak coupled motions from 0degto30deg flexion were statistically significant (p<0.05). In ACL-deficient knees, there was a strong trend (marginally not significant, p=0.07) toward greater anterior translation (12.7mm) than that in intact knees (8.0mm), whereas coupled motions in the other degrees of freedom were comparable. Because the coupled motions in all four degrees of freedom in the intact knee and ACL-deficient knee are sufficiently large to substantially affect the tibiofemoral contact area, all degrees of freedom should be included when either developing mathematical models or designing mechanical testing equipment for study of tibiofemoral contact. The increase in coupled anterior translation in ACL-deficient knees indicates the important role played by the ACL in constraining anterior translation during compressive loading.
Optimal Combination of Minimum Degrees of Freedom to be Actuated in the Lower Limbs to Facilitate Arm-Free Paraplegic Standing
Authors: Kim Joon-young , Mills James K. , Vette Albert H. , Popovic Milos R.
Published: December 2007

Arm-free paraplegic standing via functional electrical stimulation (FES) has drawn much attention in the biomechanical field as it might allow a paraplegic to stand and simultaneously use both arms to perform daily activities. However, current FES systems for standing require that the individual actively regulates balance using one or both arms, thus limiting the practical use of these systems. The purpose of the present study was to show that actuating only six out of 12 degrees of freedom (12-DOFs) in the lower limbs to allow paraplegics to stand freely is theoretically feasible with respect to multibody stability and physiological torque limitations of the lower limb DOF. Specifically, the goal was to determine the optimal combination of the minimum DOF that can be realistically actuated using FES while ensuring stability and able-bodied kinematics during perturbed arm-free standing. The human body was represented by a three-dimensional dynamics model with 12-DOFs in the lower limbs. Nakamura’s method (Nakamura, Y., and Ghodoussi, U., 1989, “Dynamics Computation of Closed-Link Robot Mechanisms With Nonredundant and Redundant Actuators,” IEEE Trans. Rob. Autom., 5(3), pp. 294–302) was applied to estimate the joint torques of the system using experimental motion data from four healthy subjects. The torques were estimated by applying our previous finding that only 6 (6-DOFs) out of 12-DOFs in the lower limbs need to be actuated to facilitate stable standing. Furthermore, it was shown that six cases of 6-DOFs exist, which facilitate stable standing. In order to characterize each of these cases in terms of the torque generation patterns and to identify a potential optimal 6-DOF combination, the joint torques during perturbations in eight different directions were estimated for all six cases of 6-DOFs. The results suggest that the actuation of both ankle flexion∕extension, both knee flexion∕extension, one hip flexion∕extension, and one hip abduction∕adduction DOF will result in the minimum torque requirements to regulate balance during perturbed standing. To facilitate unsupported FES-assisted standing, it is sufficient to actuate only 6-DOFs. An optimal combination of 6-DOFs exists, for which this system can generate able-bodied kinematics while requiring lower limb joint torques that are producible using contemporary FES technology. These findings suggest that FES-assisted arm-free standing of paraplegics is theoretically feasible, even when limited by the fact that muscles actuating specific DOFs are often denervated or difficult to access.
In Vitro Evaluation of Flow Divertors in an Elastase-Induced Saccular Aneurysm Model in Rabbit
Authors: Seong Jaehoon , Wakhloo Ajay K. , Lieber Baruch B.
Published: December 2007

Endovascular coiling is an acceptable treatment of intracranial aneurysms, yet long term follow-ups suggest that endovascular coiling fails to achieve complete aneurysm occlusions particularly in wide-neck and giant aneurysms. Placing of a stentlike device across the aneurysm neck may be sufficient to occlude the aneurysm by promoting intra-aneurysmal thrombosis; however, conclusive evidence of its efficacy is still lacking. In this study, we investigate in vitro the efficacy of custom designed flow divertors that will be subsequently implanted in a large cohort of animals. The aim of this study is to provide a detailed database against which in vivo results can be analyzed. Six custom designed flow divertors were fabricated and tested in vitro. The design matrix included three different porosities (75%, 70%, and 65%). For each porosity, there were two divertors with one having a nominal pore density double than that of the other. To quantify efficacy, the divertors were implanted in a compliant elastomeric model of an elastase-induced aneurysm model in rabbit and intra-aneurysmal flow changes were evaluated by particle image velocimetry (PIV). PIV results indicate a marked reduction in intra-aneurysmal flow activity after divertor implantation in the innominate artery across the aneurysm neck. The mean hydrodynamic circulation after divertor implantation was reduced to 14% or less of the mean circulation in the control and the mean intra-aneurysmal kinetic energy was reduced to 29% or less of its value in the control. The intra-aneurysmal wall shear rate in this model is low and implantation of the flow divertor did not change the wall shear rate magnitude appreciably. This in vitro experiment evaluates the characteristics of local flow phenomena such as hydrodynamic circulation, kinetic energy, wall shear rate, perforator flow, and changes of these parameters as a result of implantation of stentlike flow divertors in an elastomeric replica of elastase-induced saccular aneurysm model in rabbit. These initial findings offer a database for evaluation of in vivo implantations of such devices in the animal model and help in further development of cerebral aneurysm bypass devices.
Review of U.S. Medical Device Regulation
Authors: Pietzsch Jan B. , Aquino Lauren M. , Yock Paul G. , Paté-Cornell M. Elisabeth , Linehan John H.
Published: December 2007

Medical device regulation plays a significant role in the design, development, and commercialization of new medical technologies. A comprehensive understanding of the various regulatory requirements and their practical implementation is thus an essential cornerstone of successful medical device innovation. In this paper, we review the background, mission, and statutory requirements of medical device regulation in the United States. As opposed to pharmaceuticals, which have been regulated since the early 1900s, medical device regulation was not enacted before 1976, when Congress signed into law the Medical Device Amendments to the Federal Food, Drug and Cosmetic Act of 1938. The U.S. Food and Drug Administration (FDA) has implemented a risk-based classification system, which is essential in determining the regulatory pathway for a given device. Our review of the different regulatory pathways discusses the specific steps and requirements associated with each pathway, and their implications for development and testing of different types of devices. The differences in these pathways are significant, and thus require careful consideration and analysis already at early stages of development. The FDA’s Quality Systems Regulation, which outlines specific requirements for development, testing, production, and postmarket surveillance, is another important aspect of device regulation. We present its elements and relationship to design controls and other operating procedures implemented by device manufacturers, and discuss their relevance in ensuring the safety and effectiveness of marketed devices. A summary of recent additions to device regulation, implemented by the FDA to allow for adequate regulation of products that combine drugs and devices or biologics and devices (so-called combination products), completes our review. Because of the significance of device regulation for medical device innovation, we strongly support increased efforts to educate the various stakeholders involved in the medical device development process, both at the academic and professional level.
Comparison of intermittent and continuous exposure to mercuric chloride in rainbow trout (Oncothynchus mykiss), goldfish (Carassius auratus), and the fathead minnow (Pimephales ptomelas)
Authors: Handy R. D.
Published: December 2007

Rainbow trout (Oncorhynchus mykiss), goldfish (Carassius auratus), and the fathead minnow (Pimephales promelas) were exposed continuously or intermittently (24-h exposure: 24-h recovery) to a nominal peak concentration of 3 μg∙L−1 mercuric chloride for 120 h. There were no differences in the target organs or the distribution of the toxicant within internal organs between the two exposure regimes. Mercury concentrations in the tissues of intermittently exposed fish were less than those of continuously exposed fish. The lower mercury concentrations in the intermittently exposed groups arose from reduced or negligible accumulation during recovery periods rather than mercury excretion. The accumulation of mercury during intermittent exposure is roughly proportional to the exposure duration, and could therefore be predicted from a continuous exposure of equivalent total exposure duration. This proportionality exists when (1) peak concentrations of mercury are the same in both regimes, and (2) the recovery periods are short compared with the biological half-life for mercury.
Path analysis of collective properties and habitat relationships of fish assemblages in coastal plain streams
Authors: Sheldon Andrew L. , Meffe Gary K.
Published: December 2007

Collective properties of fish assemblages at 44 sites in low-gradient streams (orders 1–3) on the upper coastal plain of South Carolina, U.S.A., were highly variable among sites: richness, 2–17 species per site; density, 0.2–9.5 individuals∙m−2; mean individual mass, 0.4–22.2 g per individual; and biomass, 0.1–42.1 g∙m−2. Principal components analysis reduced 15 habitat parameters to four interpretable components that were used as orthogonal predictive variables in path analysis. Path analysis, with a directional model containing intermediate steps and multiple dependent variables, was used as an alternative to multiple regression. Two principal components, associated with velocity (and its covariates) and depth (and its covariates), were the primary correlates of biomass (R2 = 49%), richness (44%), mean size (36%), and density (20%), with cover variables contributing relatively little to any R2value. Velocity effects were negative and depth effects positive for all collective properties. Habitat effects on biomass were mediated by effects on individual fish size rather than numbers. Correlations of collective properties at sites sampled in 2 years were similar to those from the single year, habitat-based path model, implying that the path model was adequate and inclusive, and accurately reflected collective properties of these communities.
Density-dependent survival as a function of size in juvenile salmonids in streams
Authors: Marschall Elizabeth A. , Crowder Larry B.
Published: December 2007

The bioenergetic mechanism of density-dependent survival in juvenile stream salmonids was modeled using the relationship between density, food availability, and body size for a food-limited stream system. With a consumption-rate function estimated from laboratory experiments reported in the literature, we developed a function to predict maximum density of stream-resident juvenile salmonids of different sizes. This function can thus predict effective density based on both numbers and sizes of fish. Density predictions from this mechanistic function did not differ from predictions in the literature based on an empirically derived function describing the relationship between minimum territory size and body size in age-0 salmonids in streams, but it did suggest a bioenergetic mechanism for these relationships, linking size and consumption rate to the available food. Finally, we proposed a model of per capita survival rate as a function of the numbers and sizes in a cohort of stream-resident juvenile salmonids.
Regional precipitation and surface water chemistry trends in southeastern Canada (1983–1991)
Authors: Clair T. A. , Dillon P. J. , Ion J. , Papineau M. , Jeffries D. S. , Vet R. J.
Published: December 2007

We analyzed for trends of acidification related variables from 1983 to 1992 in precipitation concentrations and deposition at six sites and surface water concentrations at 111 sites located from central Ontario to eastern Newfoundland. Precipitation showed significantly decreasing H+and [Formula: see text] concentrations and deposition in central and eastern Ontario and at one of two sites in Québec (deposition only). For Ontario surface water sites, only increasing or stable [Formula: see text] trends were observed, and these had both concomitant increasing and decreasing trends for pH and (or) acid-neutralizing capacity (ANC). Despite a considerable number of lakes showing decreasing [Formula: see text] trends in Québec, pH and ANC also decreased. Québec was also the only region showing extensive evidence of increasing [Formula: see text]. The opposite situation was observed in Atlantic Canada lakes where despite increasing [Formula: see text], the dominant trend observed for pH and ANC was increasing. Trends observed for pH and ANC were used to classify the acidification status of our surface water sites: 60 of the 111 sites were found to be stable (i.e., showing no trends), 17 were continuing to acidify, and 34 were improving.
Simulation of reinforcement-corrosion-induced crack propagation in concrete by acoustic emission technique and boundary element method analysis
Authors: Farid Uddin A K.M , Ohtsu M , Hossain K M.A , Lachemi M
Published: December 2007

Corrosion of reinforcement is one of the major causes of deterioration in reinforced concrete structures. Various crack patterns are nucleated around reinforcement in concrete due to expansion of corrosion products. Crack kinematics of locations, types, and orientations are quantitatively determined by the acoustic emission (AE) – simplified Green’s functions for moment tensor analysis (SiGMA) procedure in association with laboratory tests conducted on concrete specimens simulating corrosion-induced damage. These kinematic outcomes are obtained as three-dimensional (3-D) locations and vectors, and are thus visualized in 3-D by using virtual reality modeling language (VRML). Numerical analysis is conducted by the boundary element method (BEM) based on the concept of linear elastic fracture mechanics (LEFM) to clarify the mechanisms of corrosion-induced crack extension. Relationships between dimensionless stress intensity factors and cracking types are studied by BEM. Contributions of mode I and mode II failures are dependent on the cracking types. It is found that the process of crack propagation due to corrosion of reinforcement in concrete is mostly a mode I fracture with mixed-mode and, in a few cases, mode II fracture.Key words: acoustic emission, moment tensor, corrosion cracking, stress intensity factor.
Experience with end-result specifications for granular base aggregates in Ontario
Authors: Rogers Chris , Senior Stephen
Published: December 2007

In 1982, the Ontario Ministry of Transportation (MTO) introduced end-result specifications (ERS) for the acceptance of granular base and subbase aggregates with respect to lot-by-lot statistical testing for grading and percentage of crushed particles. Under ERS, the mean and range of four test results (sublots) were used to determine the payment for specific production quantities (lots). Quality assurance (QA) sampling and testing were conducted at the aggregate source by the MTO. Materials within a lot that were, on average, marginally outside the specification limits or exhibited a wide range would be paid at a reduced contract price. Materials significantly exceeding these requirements would be rejected. In 1997, MTO introduced quality control (QC) requirements that made the contractor responsible for sampling and testing at the source. Quality assurance testing was based on a reduced number of samples taken from materials delivered to the worksite. Price adjustments, if any, were determined solely on QA test results (subject to a referee process). This paper describes in detail the steps taken to introduce these various ERS schemes. Acceptance for granular base materials at full price in 2002 has not changed significantly from 1994 and earlier years; the quantity of rejected materials has also not changed significantly over the years. It is concluded that the introduction of contractor QC testing has not significantly improved the quality of materials supplied, but neither has it had a detrimental effect.Key words: aggregate, construction, end-result specification, granular base, pavement, quality assurance, quality control, statistics, testing.
Estimation of friction coefficient of asphalt concrete road surfaces using the fuzzy logic approach
Authors: Ergun Murat
Published: December 2007

Vehicle speeds have increased very dramatically with new developments in todays automotive industry, and thus the friction behavior of roads has become very important from the safety point of view. The main aim of this paper is to estimate the friction behavior of asphalt concrete road surfaces at any speed using the fuzzy logic approach. Friction is defined in the paper, and the effects of road surface characteristics, mainly macrotexture and microtexture properties, on the friction behavior of asphalt concrete road surfaces are explained. The data measured from the different asphalt concrete road pavements (on Belgium road networks) representing different road surface characteristics are analyzed for estimating the friction behavior of roads. Both the multiple linear regression analysis and the fuzzy logic approach are used to estimate the friction coefficient of asphalt concrete road surfaces. The two approaches are compared, and it is shown that the fuzzy logic approach precisely estimates the friction coefficient of asphalt concrete road surfaces at any speed better than multiple linear regression analysis. It is possible that there is a strong relation between the asphalt concrete road surface characteristics, mainly macrotexture and microtexture, and friction.Key words: asphalt concrete road surfaces, friction, fuzzy estimation.