bluuebunny/crossref_metadata_2025 huggingface dataset:
Retreating to nature: rethinking ‘therapeutic landscapes’
Authors: Lea Jennifer
Published: March 2008

There is a long history of removing oneself from ‘society’ in order to recuperate or repair. This paper considers a yoga and massage retreat in Southern Spain, and what opportunities this retreat experience might offer for recuperation and the creation of healthy bodies. The paper positions ‘nature’ as an active participant, and as ‘enrolled’ in the experiences of the retreat as a ‘therapeutic landscape’, and questions how and what particular aspects of yoga practice (in intimate relation with place) give rise to therapeutic experiences.
A requiem for the British flora? Emotional biogeographies and environmental change
Authors: Trudgill Stephen
Published: March 2008

A change of species distributions in response to environmental change challenges cherished notions of native flora and the appropriateness of a species for a particular location. Recent writings have called for a removal of emotive descriptors of species such as ‘alien’ and ‘invasive’. There are also calls for a separation of facts and values, but it is apparent that biogeographical facts and values both have a fundamental emotional underpinning. Since the evidence of shifts in biogeographical distributions is now challenging our values, it seems that a change in philosophy is appropriate, one which recognises both the scientific evidence and an emotional need for a narrative.
Response to Smalley's discussion of ‘A call for Australian loess’
Authors: Haberlah David
Published: March 2008

A concise response to Smalley's discussion of my ‘Call for Australian loess’ paper (

Haberlah 2007
, Area 39 224–9) elaborating on past and possible future Australian contributions to the international loess debate. The suggested idea of dividing loess into three separate categories ‘glacial loess’, ‘desert loess’ and ‘mountain loess’ is questioned by emphasising common links.
In‐flight geometric calibration of different cameras of IRS‐P6 using a physical sensor model
Authors: Radhadevi P. V. , Solanki S. S.
Published: March 2008

The IRS‐P6 satellite has multi‐resolution and multispectral capabilities on a single platform. A continuous and autonomous co‐registration and geolocation of image data from different sensors with widely varying view angles and resolution is one of the unique challenges of IRS‐P6 data processing. This requires in‐flight geometric calibration of the cameras. In‐flight calibration includes alignment calibration of individual sensors and calibration between the sensors. A method for in‐flight geometric calibration and quality assessment of IRS‐P6 images is presented in this paper. The objectives of this study are to ensure the best absolute and relative location accuracy of different cameras, and the same location performance with payload steering and co‐registration of multiple bands. This is done using a viewing geometry model, given ephemeris and attitude data, precise camera geometry and datum transformation. In the model, the forward and reverse transformations between the coordinate systems associated with the focal plane, payload, body, orbit and ground are rigorously and explicitly defined. System‐level tests using comparisons to ground check points have validated the operational geolocation accuracy performance and the stability of the calibration parameters.
Parental decisions regarding prenatally detected fetal sex chromosomal abnormality and the impact of genetic counselling: An analysis of 57 cases in Taiwan
Authors: SHAW Sheng‐Wen , CHUEH Ho‐Yen , CHANG Shuenn‐Dyh , CHENG Po‐Jen , HSIEH T'sang‐T’ang , SOONG Yung‐Kuei
Published: March 2008

Objective:  To analyse parental decisions regarding pregnancies with sex chromosome abnormalities (SCA).

Methods:  Collected and reviewed records from our hospital for 1991–2005. Genetic counselling was provided by obstetricians or perinatologists.

Result:  Among 57 fetuses with SCA were 36 non‐mosaic cases (four of 36, 45,X; 12 of 36, 47,XXY; seven of 36, 47,XYY, 13 of 36, 47,XXX) and 21 mosaic cases (15 of 21, 45,X mosaicism). Only 20% of 45,X mosaic pregnancies were continued, whereas all other mosaic pregnancies (100%) were continued (P = 0.004). Of 32 SCA cases counselled by a perinatologist, 66% (21 of 32) were continued. In contrast, 36% (nine of 25) of cases counselled by a general obstetrician were continued, a barely significant difference (P = 0.048). More couples chose to continue pregnancies in recent years.

Conclusion:  Genetic counselling by well‐trained specialists is valuable, and the trend towards fewer terminations at our centre suggests improved parental knowledge of pathology associated with SCA.
Audit of endometrial biopsy at outpatient hysteroscopy
Authors: GHALY Simon , DE ABREU LOURENCO Richard , ABBOTT Jason A.
Published: March 2008

Background and aim:   Outpatient hysteroscopy (OPH) and endometrial biopsy (EMB) are less invasive alternatives to inpatient hysteroscopy and dilatation and curettage for assessment of the endometrium. Using local anaesthetic, the procedure is readily tolerated and can be completed in an ambulatory setting. This study aims to audit OPH and EMB conducted over three consecutive years with regard to the ability to complete the procedure and subsequent pathology.

Methods:  Data were retrospectively collected from the medical records of patients who underwent OPH during the study period. Data collected included demography, medical history, procedure details and outcome. An indicative assessment of the resource requirements for provision of these services in an outpatient versus inpatient setting was also conducted based on published cost information.

Results:  Between June 2003 to June 2006, 435 OPH were performed and 427 of these were available for audit. Four hundred and five (94.8%) of the procedures were successful. Sixty‐five (18.8%) EMBs were reported to be insufficient, of which 41 (63%) were in postmenopausal women (P < 0.001). Women who presented with postmenopausal bleeding were significantly more likely to have an insufficient sample (P < 0.001). The Australian Refined Diagnosis Related Groups cost for inpatient hysteroscopy is $A1,786, including $A711 in theatre costs and $A258 in ward costs. These costs are not incurred with OPH.

Conclusion:  This study indicates that hysteroscopy and EMB can be easily and successfully performed as an outpatient procedure in Australia. Pathology can be readily identified and management planned. Moreover, an opportunity exists for a reduction in resource use by utilising this procedure instead of inpatient hysteroscopy where possible.
Laparoscopic transabdominal cervico‐isthmic cerclage: A minimally invasive approach
Authors: REID Geoffrey D. , WILLS Hannah J. , SHUKLA Anshumala , HAMMILL Peter
Published: March 2008

Background:  While the traditional approach to management of cervical insufficiency has been the insertion of a transvaginal cerclage during pregnancy, a transabdominal cervico‐isthmic suture is indicated in certain patients. This procedure is traditionally performed via laparotomy. Laparoscopic transabdominal cervico‐isthmic cerclage (LTCC) placement, however, confers the benefit of the low morbidity associated with laparoscopy.

Aims:  To describe the technique and outcomes of LTCC in three cases.

Methods:  LTCC was performed using Mersilene tape at the level of the internal cervical os in the prepregnancy period in three patients: one with previous cervical amputation and two with previous failed cervical cerclage. Procedures were performed at a tertiary level endoscopic unit, Sydney, Australia.

Results:  The laparoscopic approach enabled placement of a suture with no morbidity, and rapid patient recovery in these cases.

Conclusions:  Laparoscopic cervical cerclage proved technically feasible and safe for a surgeon trained in laparoscopic suturing methods.
Cauda equina syndrome post‐caesarean section
Authors: CHOW Jason , CHEN Kenneth , SEN Rahul , STANFORD Ralph , LOWE Sandra
Published: March 2008

Cauda equina syndrome is rarely associated with pregnancy, with few cases reported in the literature. The majority of cases describe antenatal presentations, with only one case manifesting post‐partum, three weeks after a normal vaginal delivery. We outline a case of cauda equina syndrome following caesarean section in a patient with known lumbar disc disease, and discuss the contribution of the mode of delivery and anaesthesia as precipitants of disc herniation causing cauda equina compression. We conclude that vigilance, particularly in the post‐partum setting, be attributed towards the neurological surveillance of women with known disc disease.
Genital human papillomavirus screening by gene chip in Chinese women of Guangdong province
Authors: LIN Min , YANG Li‐Ye , LI Lie‐Jun , WU Jiao‐Ren , PENG You‐Peng , LUO Zhao‐Yun
Published: March 2008

Background:  Human papillomavirus (HPV) infections are associated with cervical cancer. There were only a few reports and detailed data about epidemiological research of HPV infection in general population of China.

Aims:  To determine the prevalence of genital HPV infection in Chinese women of Guangdong province.

Methods:   A total of 1705 women were screened by gene chip. All HPV‐positive women were further examined by ThinPrep liquid‐based cytology test (TCT), and the cervical biopsies of those women with positive HPV‐DNA and abnormal TCT were collected for pathological diagnosis.

Results:  The overall HPV prevalence was 9.03% (154 of 1705), and 72.3% (126 of 154) of total positive samples were high‐risk types, with higher prevalence of types 52, 58, 16, 18 and CP8304. For women aged 51 years or older, the overall high‐risk HPV prevalence was 12.2% (24 of 179), which was obviously higher than those of other age groups (P < 0.05).

Conclusions:  Our results showed that the HPV prevalence in Guangdong is very similar to the world level. Unlike most previous studies, our findings suggest that HPV prevalence increased with age, and that the predominant genotypes in this area were HPV 52 and 58.
Cytotoxicity and Genotoxicity of Bovine Pericardium Preserved in Glycerol
Authors: Rodas Andrea C.D. , Maizato Marina J.S. , Leirner Adolfo A. , Pitombo Ronaldo N.M. , Polakiewicz Bronislaw , Beppu Marisa M. , Higa Olga Z.
Published: March 2008

Abstract:  Bovine pericardium is a widely utilized biomaterial. Usually, after harvesting, it is advantageous that the pericardium be immersed in glycerol to improve its shelf life. This can induce some degree of toxicity in the material. The studies were performed in compliance with the rules of ISO 10993 and OECD 487, in the biological evaluation of medical devices. The material was prepared without previous washing. After sterilization by gamma radiation the pericardium was immersed in RPMI 1640 culture medium to fulfill the extraction condition. The same extract was employed in the cytotoxic and genotoxic tests. The procedures were carried out with Chinese hamster ovary cell line and to determine the cytotoxicity, a colorimetric method with the tetrazolium compound MTS was used. For the genotoxicity, following the in vitro micronucleus assay, the test was developed with and without metabolic activation. The Cytotoxicity Index was graphically estimated at the extract concentration of 78%. In the genotoxicity test, the average value of cell proliferation index was found to be 1.62 ± 0.02 with S9 metabolic activator and 1.91 ± 0.01 without S9 metabolic activator. Both values are similar to the negative control value in the micronucleus assay. We observed that although the pericardium preserved in glycerol shows a certain level of cytotoxicity, it does not show any genotoxicity.
The Influence of the Loading Mode on the Stress Distribution on the Connector Region of Metal‐ceramic and All‐ceramic Fixed Partial Denture
Authors: Motta Andréa Barreira , Pereira Luiz Carlos , Da Cunha Andréia R.C.C. , Duda Fernando Pereira
Published: March 2008

Abstract:  Studies pertaining to the mechanical behavior of fixed partial dentures (FPDs) frequently found the highest tensile stress values at the connector region when load is applied at the pontic central region. The connector region is considered the weakest point of the prosthesis with the greatest potential of fractures, regardless of the material used. This 2D finite element study compared the stress distribution on three‐element all‐ceramic and metal‐ceramic FPDs with different loading conditions. Three FPD models were designed: (i) metal‐ceramic FPD; (ii) all‐ceramic FPD with the veneering porcelain only on the occlusal face; and (iii) all‐ceramic FPD with the veneering porcelain on the occlusal and cervical face of the pontic. Loads of 100 N were applied following these simulations: (i) distributed on all working cusps; (ii) only on the abutment teeth; and (iii) only on the pontic. There is a significant change on the stress distribution and on the tensile stress values when the load configuration is changed. The stress distribution from the load applied on the abutments was significantly better compared with the other two load simulations. When the loads were applied on the pontic and distributed on all working cusps, the highest tensile stress values appeared on the cervical region of the connectors between the abutments and the pontic. However, when the load was applied on the abutment teeth, the maximum tensile stress value significantly decreased and was located on the occlusal region of the connectors. In fact, the load applied on the pontic region does not simulate the clinical situation. Studies using this load configuration have overestimated the connector regions as having the highest probability of failures.
Production, Microstructural Characterization and Mechanical Properties of As‐Cast Ti‐10Mo‐xNb Alloys
Authors: Gabriel Sinara Borborema , Nunes Carlos Angelo , Soares Glória de Almeida
Published: March 2008

Abstract:  Beta titanium (Ti) alloys are one of the most promising groups of Ti alloys for biomedical applications. This work presents the production, microstructural characterization, and mechanical properties of as‐cast Ti‐10Mo‐xNb (x = 0, 3, 6, 9, 20, and 30) alloys. They were produced via arc melting and characterized by scanning electron microscopy and X‐ray diffraction. The density of each alloy was measured by the Archimedes method and the mechanical characterization was carried out by using the Vickers microhardness test and Young's modulus measurements. The results show a near β microstructure for niobium (Nb) contents lower or equal to 9 wt% while β single‐phase microstructure was obtained for higher Nb additions. The microhardness values decreased with the increase of Nb content in the alloys. The elastic modulus values of Ti‐10Mo‐3Nb and Ti‐10Mo‐20Nb alloys were lower than those of cp Ti and Ti‐6Al‐4V.
Mechanical and Morphological Evaluation of Osteochondral Implants in Dogs
Authors: Bavaresco Vanessa P. , Garrido Luiz , Batista Nilza A. , Malmonge Sônia M. , Belangero William D.
Published: March 2008

Abstract:  The mechanical behavior of osteochondral defects was evaluated in this study with the intention of developing alternative procedures. Cylindrical pins (5.00 mm in diameter and in height) made of pHEMA hydrogel covered ultra‐high molecular weight polyethylene (UHMWPE) or β‐tricalcium phosphate (β‐TCP) matrix were used. Ostoechondral defects were caused in the knees of adult dogs and the evaluation was carried out after a 9‐month follow‐up period. The mechanical behavior of the implants was evaluated by means of an indentation creep test that showed that the UHMWPE matrix maintained its viscoelastic behavior even after follow‐up time, while the β‐TCP matrix osteochondral implants presented significant alterations. It is believed that the β‐TCP osteochondral implants were unable to withstand the load applied, causing an increase of complacency when compared to the UHMWPE osteochondral implants. Based on micro and macroscopic analysis, no significant wear was observed in either of the osteochondral implants when compared to the controls. However, morphological alterations, with fragmentation indices in the patella, were observed either due to friction with the hydrogel in the first postoperative months or due to forming of a dense conjunctive tissue. This wear mechanism caused on the counterface of the implant (patella) was observed, notwithstanding the osteochondral implant studied.
New Centrifugal Blood Pump With Dual Impeller and Double Pivot Bearing System: Wear Evaluation in Bearing System, Performance Tests, and Preliminary Hemolysis Tests
Authors: Bock Eduardo , Ribeiro Adriana , Silva Maxwell , Antunes Pedro , Fonseca Jeison , Legendre Daniel , Leme Juliana , Arruda Celso , Biscegli José , Nicolosi Denys , Andrade Aron
Published: March 2008

Abstract:  A new dual impeller centrifugal blood pump has been developed as a research collaboration between Baylor College of Medicine and Institute Dante Pazzanese of Cardiology for long‐term left ventricle assist device (LVAD). A design feature of this new pump is a dual impeller that aims to minimize a stagnant flow pattern around the inlet port. Several different materials were tested in order to adopt a double pivot bearing design originally developed by Prof. Dr. Yukihiko Nosé from Baylor College of Medicine. Hydraulic performance tests were conducted with two different inlet ports' angle configurations 30° and 45°. Pump with inlet port angle of 45° achieved best values of pressure ahead and flow after 1800 rpm. Preliminary hemolysis tests were conducted using human blood. The pump showed good performance results and no alarming trace of hemolysis, proving to be a feasible long‐term LVAD.
An Electro‐Fluid‐Dynamic Simulator for the Cardiovascular System
Authors: Felipini Celso Luiz , De Andrade Aron José Pazin , Lucchi Júlio César , Da Fonseca Jeison Willian Gomes , Nicolosi Denys
Published: March 2008

Abstract:  This work presents the initial studies and the proposal for a cardiovascular system electro‐fluid‐dynamic simulator to be applied in the development of left ventricular assist devices (LVADs). The simulator, which is being developed at University Sao Judas Tadeu and at Institute Dante Pazzanese of Cardiology, is composed of three modules: (i) an electrical analog model of the cardiovascular system operating in the PSpice electrical simulator environment; (ii) an electronic controller, based on laboratory virtual instrumentation engineering workbench (LabVIEW) acquisition and control tool, which will act over the physical simulator; and (iii) the physical simulator: a fluid‐dynamic equipment composed of pneumatic actuators and compliance tubes for the simulation of active cardiac chambers and big vessels. The physical simulator (iii) is based on results obtained from the electrical analog model (i) and physiological parameters.
Gender Disparity in the Use of Cardiac Resynchronization Therapy in the United States
Authors: ALAEDDINI JAMSHID , WOOD MARK A. , AMIN MITESH S. , ELLENBOGEN KENNETH A.
Published: March 2008

Background: Although several studies have shown the effectiveness of cardiac resynchronization therapy (CRT) for advanced congestive heart failure (CHF), gender differences in utilization of CRT are not known.

Methods: We used the Healthcare Cost and Utilization Project (HCUP) to study national rates for admissions due to CHF along with procedures for initial CRT implantation, including both CRT‐defibrillator (CRT‐D) and CRT‐pacemakers (CRT‐P) during the years of 2002–2004. Chi‐square tests were used for comparison between number of women and men. A P < 0.05 was considered significant.

Result: Women had consistently higher rates of admission for CHF during each year (574,037 (54%) vs 482,005 (46%), 2002; 601,181 (54%) vs 517,202 (46%), 2003; and 580,913 (53%) vs 521,280 (47%), 2004). The number of initial CRT device implantations (both CRT‐D and CRT‐P) was significantly lower during each year for women compared to men (659 (25%) vs 1,931 (75%), 2002; 6,928 (26%) vs 19,646 (74%), 2003; and 11,286 (27%) vs 42,196 (73%), 2004; P < 0.01 for all). Both CRT‐P and CRT‐D were used less frequently in women compared to men; however, this difference was consistently less prominent during each year with CRT‐P compared to CRT‐D (301 (41%) CRT‐P vs 358 (19%) CRT‐D, 2002; 659 (39%) CRT‐P vs 2,530 (28%) CRT‐D, 2003; and 2,891 (39%) CRT‐P vs 8,395 (24%) CRT‐D, 2004; P < 0.05).

Conclusion: Our data clearly demonstrate a significant gender disparity in utilization of CRT devices. Further studies are needed to find possible reasons behind this disparity.
Outcome of Young Patients with Abandoned, Nonfunctional Endocardial Leads
Authors: SILVETTI MASSIMO S. , DRAGO FABRIZIO
Published: March 2008

Background:

Transvenous leads may fail and may be extracted or abandoned. There are no reports of the outcome of children with abandoned nonfunctional leads.

Methods:

We evaluated retrospectively the outcome of these patients, in our population of pacemaker (PM) patients. Data are reported as median (range).

Results:

In 18 patients (of 245, 7%) with endocardial pacing systems implanted at 4 (0.3–19) years of age (15 VVIR and 3 DDD PM), 19 leads (16 ventricular, 3 atrial) failed (abnormal threshold increase in seven leads; exit block in nine including three atrial leads; insulation break in three) after 10 (3–15) years, and were abandoned. At 13 (6–30) years of age, seven patients received VDD PM, seven VVIR, three DDD, and one patient an epicardial system. Median number of abandoned leads is one (two in two patients). Final cross‐sectional area (CSA) of the implanted leads is eight (2–14) mm2. All the procedures were successfully completed. Follow‐up (FU) duration is 4 (1–10) years. All new leads are functioning normally. No tricuspid valve dysfunction or new venous occlusion occurred. Two cases of lead endocarditis occurred after 5 and 10 years of follow‐up in patients with two ventricular leads. No specific risk factors for endocarditis were identified.

Conclusions:

Abandonment of a nonfunctioning lead is a palliative procedure, technically feasible, with no short‐term complication. Two patients experienced late endocarditis of the leads.
Left Ventricular Pacing Lead Positioning in the Target Vein of the Coronary Sinus: Description of a Challenging Case
Authors: FRATTINI FOLCO , RORDORF ROBERTO , ANGOLI LUIGI , PENTIMALLI FRANCESCO , VICENTINI ALESSANDRO , PETRACCI BARBARA , MAGRINI GIULIA , LANDOLINA MAURIZIO
Published: March 2008

The optimal left ventricular pacing location for cardiac resynchronization therapy should be individualized according to the site of maximal mechanical delay. However, the presence of vein stenosis or kinking in coronary sinus (CS) anatomy could hamper lead implantation in the target vessel. We describe the case of a patient with dilated cardiomyopathy and a dual‐chamber pacemaker referred for upgrading to a biventricular device owing to New York Heart Association III heart failure symptoms. Tissue Doppler analysis before implantation showed that the area of maximum activation delay was located in the posterolateral region of the left ventricle. Insertion of the lead into a posterolateral vein of the CS by means of the standard over‐the‐wire approach was unsuccessful due to the presence of a stenosis at the ostium of the vein. Lead placement in an anterior vein of the CS was unsatisfactory owing to a poor local delay from QRS onset. After balloon vein angioplasty, the pacing lead passed through the stenotic tract at the ostium of the target vein and was successfully positioned in the posterolateral region. Three months after pacemaker implantation, echocardiography showed an important reduction in the indexes of both inter‐ and intraventricular asynchrony and a significant left ventricular reverse remodeling
Interventional Approach to CRT in a Patient with Drainage of the Superior Vena Cava into the Coronary Sinus
Authors: WORLEY SETH JOSEPH , GOHN DOUGLAS CHARLES , PULLIAM ROBERT WARD
Published: March 2008

A persistent left superior vena cava markedly increases the size of the coronary sinus (CS), which can increase the difficulty of left ventricular (LV) lead placement in patients receiving cardiac resynchronization therapy (CRT). We present a case where the entire superior vena cava drains into the coronary sinus, creating a massive CS. We also describe an interventional approach to LV lead implantation utilizing a combination of delivery systems from different vendors.
Electroanatomical Mapping in Partial Atrial Standstill for Visualization of Atrial Viability and a Suitable Pacing Site
Authors: ARIMOTO TAKANORI , SUKEKAWA HIROYASU , TAKAYAMA SHIN , IKENO EIICHIRO , TAKEISHI YASUCHIKA , KUBOTA ISAO
Published: March 2008

Partial atrial standstill is characterized by the failure of atrial activity either spontaneously or in response to electrical stimulation in restricted site of atria. In this case with bradycardia, atrial standstill was restricted to the lateral and posterior right atrium. The markedly prolonged intraatrial conduction delay was observed in the superior to septal region of the right atrium. The electroanatomical mapping was successfully utilized to estimate atrial activity and to find a suitable site for atrial lead placement. The electroanatomical mapping may become an innovated strategy to estimate atrial electrical status in partial atrial standstill.
Pseudo Pacemaker Stimuli
Authors: SMELLEY MATTHEW P. , CHILDERS RORY , KNIGHT BRADLEY P.
Published: March 2008

Current electrocardiographic technology is limited in its ability to detect pacemaker stimuli secondary to the use of 150 Hz low‐pass bandwidth filters designed to block high‐frequency interference. Software solutions to improve the sensitivity of pacemaker stimulus detection are associated with imperfect specificity. The following case reports include three patients who do not have a pacing device, but were identified by a computer‐based preliminary interpretation of a routine 12‐lead surface electrocardiogram (ECG) as having a paced rhythm.
Experience and Results During Transition from Radiofrequency Ablation to Cryoablation for Treatment of Pediatric Atrioventricular Nodal Reentrant Tachycardia
Authors: AVARI JENNIFER N. , JAY KATHLEEN S. , RHEE EDWARD K.
Published: March 2008

Background: Cryoablation has emerged as a new, theoretically safer, modality for treating atrioventricular nodal reentrant tachycardia (AVNRT). The purpose of this study is to compare procedural aspects and outcomes during the transition from radiofrequency (RF) ablation to cryoablation for pediatric AVNRT.

Methods: Data were obtained retrospectively from 80 consecutive pediatric patients who underwent AVNRT ablation from 10/2001– 4/2006 (RF n = 42, Cryo n = 38). Statistical analysis was performed using unpaired t‐test, chi‐square test, and analysis of variance.

Results: RF ablations were performed anatomically in NSR while three different mapping techniques were used during cryoablation: ablation during AVNRT (26%), anatomic in NSR (48%), and anatomic with S1 S2 pacing (26%). There was no difference in the number or duration of lesions between the three cryo subgroups. Acute success was obtained in 95% of RF and 97% of cryo cases. There was no difference in the number of total, mapping, or full‐duration lesions between the RF and cryogroups. Despite accounting for longer cryolesion time, total ablation time (P < 0.001), mapping time (P = 0.002), and full duration lesion time (P < 0.001) were longer in the cryogroup. There was no significant difference in total procedure time; fluoroscopy time was shorter in the cryoablation group (P = 0.049). There was one confirmed recurrence of tachycardia in each group with a 2% recurrence rate.

Conclusions: Cryoablation for treatment of pediatric AVNRT is as safe and efficacious as RF ablation. Although cryolesions are intrinsically longer in duration, total procedure times were not increased and fluoroscopy times were decreased compared to RF.
Nonparametric and Semiparametric Group Sequential Methods for Comparing Accuracy of Diagnostic Tests
Authors: Tang Liansheng , Emerson Scott S. , Zhou Xiao‐Hua
Published: March 2008

Summary Comparison of the accuracy of two diagnostic tests using the receiver operating characteristic (ROC) curves from two diagnostic tests has been typically conducted using fixed sample designs. On the other hand, the human experimentation inherent in a comparison of diagnostic modalities argues for periodic monitoring of the accruing data to address many issues related to the ethics and efficiency of the medical study. To date, very little research has been done on the use of sequential sampling plans for comparative ROC studies, even when these studies may use expensive and unsafe diagnostic procedures. In this article we propose a nonparametric group sequential design plan. The nonparametric sequential method adapts a nonparametric family of weighted area under the ROC curve statistics (Wieand et al., 1989, Biometrika 76, 585–592) and a group sequential sampling plan. We illustrate the implementation of this nonparametric approach for sequentially comparing ROC curves in the context of diagnostic screening for nonsmall‐cell lung cancer. We also describe a semiparametric sequential method based on proportional hazard models. We compare the statistical properties of the nonparametric approach with alternative semiparametric and parametric analyses in simulation studies. The results show the nonparametric approach is robust to model misspecification and has excellent finite‐sample performance.
Inference for Constrained Estimation of Tumor Size Distributions
Authors: Ghosh Debashis , Banerjee Moulinath , Biswas Pinaki
Published: March 2008

SummaryIn order to develop better treatment and screening programs for cancer prevention programs, it is important to be able to understand the natural history of the disease and what factors affect its progression. We focus on a particular framework first outlined byKimmel and Flehinger(1991,Biometrics,47,987–1004) and in particular one of their limiting scenarios for analysis. Using an equivalence with a binary regression model, we characterize the nonparametric maximum likelihood estimation procedure for estimation of the tumor size distribution function and give associated asymptotic results. Extensions to semiparametric models and missing data are also described. Application to data from two cancer studies is used to illustrate the finite‐sample behavior of the procedure.
Variable Selection with Incomplete Covariate Data
Authors: Claeskens Gerda , Consentino Fabrizio
Published: March 2008

SummaryApplication of classical model selection methods such as Akaike's information criterion (AIC) becomes problematic when observations are missing. In this article we propose some variations on the AIC, which are applicable to missing covariate problems. The method is directly based on the expectation maximization (EM) algorithm and is readily available for EM‐based estimation methods, without much additional computational efforts. The missing data AIC criteria are formally derived and shown to work in a simulation study and by application to data on diabetic retinopathy.
Identification of Three Highly Confused Marine Loxophyllum (Ciliophora: Pleurostomatida) with a Key to Seven Congeners from the China Sea
Authors: LIN XIAOFENG , AL‐RASHEID KHALED A. S. , AL‐QURAISHY SALEH A. , AL‐FARRAJ SALEH A. , SONG WEIBO
Published: March 2008

ABSTRACT. Three highly confused Loxophyllum helus‐like morphotypes (i.e. Loxophyllum rostratum Cohn, 1866, Loxophyllum sinicum n. sp., and Loxophyllum simplex Kahl, 1933) found in mariculture waters near the coast of Qingdao, China, were investigated with emphasis on their live morphology and infraciliature. Comparative descriptions of these three organisms are presented and synonyms are critically discussed. The validity of L. sinicum n. sp. is confirmed mainly by the combination of the distribution of extrusomes, features of general living morphology, morphometric data, and the characters of the somatic ciliature. Two previously reported organisms under the name of L. helus by Dragesco (1966, variety a) and by Dragesco and Dragesco‐Kernéis (1986) are discussed and are believed to be synonyms of L. sinicum. Furthermore, two isolates described by Dragesco (1960) and Ozaki and Yagiu (1943) under the name of L. helus are very likely, in our opinion, misidentifications, and might be two unknown forms. In the light of the current study, a key is presented to the seven clearly defined marine Loxophyllum species found in the coastal areas of north China Sea.
Two New Ciliates from Hong Kong Coastal Water: Orthodonella sinica n. sp. and Apokeronopsis wrighti n. sp. (Protozoa: Ciliophora)
Authors: LONG HONGAN , LIU HONGBIN , LIU WEIWEI , MIAO MIAO , HU XIAOZHONG , LIN XIAOFENG , SONG WEIBO
Published: March 2008

ABSTRACT. The morphology and infraciliature of Orthodonella sinica n. sp. and Apokeronopsis wrighti n. sp., isolated from the coastal water off Hong Kong, were investigated in living and stained specimens. Orthodonella sinica n. sp. is diagnosed as: a marine Orthodonella 150–310 × 40–80 μm in vivo; with a dominant beak‐like projection at the anterior end; about 70 somatic kineties; 84–126 dikinetids in the synhymenium; one contractile vacuole in the posterior one‐fourth of cell, near the left margin; one conspicuous dorsal suture. Apokeronopsis wrighti n. sp. is diagnosed as: an Apokeronopsis about 150–230 × 35–55 μm in vivo; dark‐reddish blood‐cell‐shaped cortical granules grouped in three rows on the ventral side and two rows on the dorsal side; 23–35 cirri in the right mid‐ventral rows (MVR) and 23–32 cirri in the left MVR; six to eight buccal, two frontoterminal, 30–42 left marginal, and 32–43 right marginal cirri; 21–30 transverse cirri extending anteriorly beyond the level of mid‐body; consistently three dorsal kineties. The separation of A. wrighti n. sp. and its highly similar congeners Apokeronopsis crassa and Apokeronopsis bergeri was supported by comparison of their SSrRNA gene sequences.
Low Friction in CuO‐Doped Yttria‐Stabilized Tetragonal Zirconia Ceramics: A Complementary Macro‐ and Nanotribology Study
Authors: Tocha Ewa , Pasaribu Henry R. , Schipper Dik J. , Schönherr Holger , Vancso G. Julius
Published: March 2008

The tribological behavior of CuO‐doped yttria‐stabilized tetragonal zirconia (3Y‐TZP) ceramics in the absence of additional lubricants was characterized by macroscale pin‐on‐disk measurements and nanoscale atomic force microscopy (AFM) for a broad range of velocities. The previously observed low shear strength interfacial layers generated in pin‐on‐disk tracks by Al2O3 ball counter surfaces on CuO‐doped 3Y‐TZP, as well as virgin surfaces, were probed quantitatively by AFM with Si3N4 tips as the counter surface. The observed trends in nanoscale coefficient of friction determined by AFM were found to be in agreement with data acquired using a pin‐on‐disk tribometer. The combined data support the notion that a layer of surface contaminations is removed during the initial sliding, and wear of high asperities occurs. Subsequently, an interfacial layer with low shear strength is generated during sliding. While these results do not provide an exhaustive explanation for the process of layer formation, they represent the first report of bridged nano‐ and macrotribological analysis of a compositionally heterogeneous low‐friction, low‐wear ceramic material and further confirm some of the key assumptions for the deterministic model reported previously by Pasaribu and Schipper.
Emergency Medicine Subinternship: Does a Standard Clinical Experience Improve Performance Outcomes?
Authors: Lampe Christopher J. , Coates Wendy C. , Gill Andrew M.
Published: March 2008

Background:  The emergency medicine (EM) subinternship provides a varied experience for senior medical students depending on gender, specialty choice, and interest. A didactic curriculum can be standardized, but the clinical component is difficult to control. Students can be directed to see patients with specific chief complaints.

Objectives:  To assess whether a clinical requirement of 10 predetermined cases improves general knowledge as measured on an objective exam.

Methods:  This was a prospective, nonrandomized, case‐controlled study at a public teaching hospital. Students were assigned to the control group (CG) or test group (TG) by alternating block rotations over 6 months. The CG saw emergency department (ED) patients according to interest and faculty direction. The TG was also required to identify ten specific chief complaints. Patient encounters were recorded in computerized logs. A 10‐question pretest assessed preexisting knowledge of each chief complaint, and a 40‐question final exam tested general EM knowledge. Descriptive statistics measured demographic data. Groups were compared by Fisher’s exact test. Difference in means testing was performed to see if pre‐ to posttest differences varied by group. Multivariate analysis controlled for gender and specialty choice.

Results:  Eighteen CG students saw a mean of 57 patients, and 24 TG students saw a mean of 54 patients; 1 CG student (6%) and 7 TG students (31.8%) saw all 10 required cases (Fisher’s exact test p = 0.044). Difference in means testing demonstrated a greater relative change in performance (13.4% points) by the TG relative to the CG on a general knowledge exam, compared with their performance on a brief pretest (p = 0.014). The authors performed multivariate regression controlling for pretest score, gender, and EM specialty choice, and neither gender nor intended EM specialty choice was a contributing factor to the improved performance. A greater relative change in performance (7% points) in the TG exam score was found when compared to the CG (p = 0.020).

Conclusions:  Students who participated in the usual didactic curriculum and were required to see ED patients with representative chief complaints performed better on a general EM exam than those who employed common methods of choosing patients.
TASER X26 Discharges in Swine Produce Potentially Fatal Ventricular Arrhythmias
Authors: Walter Robert J. , Dennis Andrew J. , Valentino Daniel J. , Margeta Bosko , Nagy Kimberly K. , Bokhari Faran , Wiley Dorion E. , Joseph Kimberly T. , Roberts Roxanne R.
Published: March 2008

Objectives:  Data from the authors and others suggest that TASER X26 stun devices can acutely alter cardiac function in swine. The authors hypothesized that TASER discharges degrade cardiac performance through a mechanism not involving concurrent acidosis.

Methods:  Using an Institutional Animal Care and Use Committee (IACUC)‐approved protocol, Yorkshire pigs (25–71 kg) were anesthetized, paralyzed with succinylcholine (SCh; 2 mg/kg), and then exposed to two 40‐second discharges from a TASER X26 with a transcardiac vector. Vital signs, blood chemistry, and electrolyte levels were obtained before exposure and periodically for 48 hours postdischarge. Electrocardiograms and echocardiography (echo) were performed before, during, and after the discharges. p‐Values < 0.05 were considered significant.

Results:  Electrocardiograms were unreadable during the discharges due to electrical interference, but echo images showed unmistakably that cardiac rhythm was captured immediately at a rate of 301 ± 18 beats/min (n = 8) in all animals tested. Capture continued for the duration of the discharge and in one animal degenerated into fatal ventricular fibrillation (VF). In the remaining animals, ventricular tachycardia (VT) occurred postdischarge for 1–17 seconds, whereupon sinus rhythm was regained spontaneously. Blood chemistry values and vital signs were minimally altered postdischarge and no significant acidosis was seen.

Conclusions:  Extreme acid–base disturbances usually seen after lengthy TASER discharges were absent with SCh, but TASER X26 discharges immediately and invariably produced myocardial capture. This usually reverted spontaneously to sinus rhythm postdischarge, but fatal VF was seen in one animal. Thus, in the absence of systemic acidosis, lengthy transcardiac TASER X26 discharges (2 × 40 seconds) captured myocardial rhythm, potentially resulting in VT or VF in swine.
Factors Associated with Helmet Use among Motorcycle Users in Karachi, Pakistan
Authors: Khan Imran , Khan Abdullah , Aziz Fatima , Islam Muhammad , Shafqat Saad
Published: March 2008

Objectives:  Wearing a helmet is the single most effective measure for preventing head injuries in motorcycle users. The authors undertook this study to estimate compliance and determine reasons for noncompliance with helmet use among motorcyclists in their community.

Methods:  This was a cross‐sectional survey of motorcyclists in three large randomly selected public‐access parking spaces across Karachi, Pakistan’s largest city. Questions covered personal demographics, frequency of helmet use, reasons for use or nonuse, and knowledge of local helmet laws. Analysis was based on frequencies and group comparisons using chi‐square test or independent sample t‐test.

Results:  Of the 300 (100% male) subjects, 169 (56%) reported using helmets regularly. Users listed injury prevention (78%) as the major reason for compliance, while nonusers listed physical discomfort (44%) and limited vision (25%) as the leading reasons for noncompliance. In univariate analysis, helmet users were significantly better educated than nonusers and were more likely to believe that helmets are protective (p = 0.002) and that passengers should also wear helmets (p < 0.001). The significance of these variables persisted in multivariate analysis. Several other variables (such as mean age, marital status, and knowledge of helmet laws) did not differ between users and nonusers.

Conclusions:  Helmets are underused by motorcyclists in the authors’ community. This study underscores the need for improved helmet design, public understanding, intense public education, and rigorous law enforcement in raising compliance with helmet use and minimizing the risk of preventable trauma.
Verapamil Toxicity Dysregulates the Phosphatidylinositol 3‐Kinase Pathway
Authors: Bechtel Laura K. , Haverstick Doris M. , Holstege Christopher P.
Published: March 2008

Objectives:  Recent animal research and clinical case reports suggest benefit from high‐dose insulin therapy (HDIT) for the treatment of calcium channel blocker (CCB) toxicity. One molecular signaling pathway, the phosphatidylinositol 3‐kinase (PI3K) pathway, that contributes to CCB toxicity and the efficacy of HDIT, was examined for a role in this phenomenon.

Methods:  A differentiated 3T3‐L1 adipocyte model system was utilized to characterize metabolic and molecular signaling events dysregulated in response to acute CCB toxicity. Glucose uptake assays were performed in the presence of representatives of three classes of CCB drugs, and the ability of HDIT to reverse observed inhibition was assessed. Western blot analyses were utilized to probe which insulin‐dependent signaling pathway was inhibited by CCB toxicity.

Results:  Representative compounds from the dihydropyridine and phenylalkylamine classes of CCBs were more effective at inhibiting glucose uptake in differentiated 3T3‐L1 adipocytes than a representative from the benzothiazepine class. Phosphorylation at serine 473 of the Akt protein (P‐Akt), a protein representing a common pathway for insulin receptors (IR), insulinlike growth factor receptors (IGFR), and hybrid receptors formed by IR and IGFR subunits, was abolished in the presence of toxic doses of the phenylalkylamine CCB verapamil. Phosphorylation at serine 473 of Akt was rescued in the presence high concentrations of insulin.

Conclusions:  These data suggest that dysregulation of the insulin‐dependent PI3K pathway is partially responsible for insulin resistance and the hyperglycemic state observed in response to acute CCB toxicity.
Quantitative computed tomography bone mineral density measurements in irradiated and non‐irradiated minipig alveolar bone: an experimental study
Authors: Verdonck Henk W. D. , Meijer Gert J. , Nieman Fred H. , Stoll Christian , Riediger Dieter , De Baat Cees
Published: March 2008

Objective: The objective of this study was to analyse the effect of irradiation on bone mineral density (BMD).

Materials and methods: All maxillary and mandibular pre‐molars and molars of six minipigs were extracted. After a 3‐month healing period, the maxilla and mandibles of three minipigs received three irradiation exposures at a total dose of 24 Gy. At 3 months after irradiation, quantitative computed tomography (QCT) was performed. As a reference, a calibration bone phantom with pre‐determined BMD was attached to the head of the minipigs. The QCT data were imported into a software program to calculate the BMD of the alveolar bone and the calibration bone phantom. In order to compare BMD values of individual minipigs, the so‐called bone mineral density quotient (BMDQ) was created, dividing the BMD value of the alveolar bone by the BMD value of the calibration bone phantom.

Results: Mean BMDQ values appeared to be higher in irradiated than in non‐irradiated minipigs. However, the difference was not significant. In both irradiated and non‐irradiated minipigs, the average mandibular BMDQ values were statistically significantly higher than the average maxillary BMDQ values (P=0.003). The P‐values of the Student t‐test, determining the irradiation effect, were 0.11 for maxillary, 0.14 for mandibular, and 0.07 for overall peri‐implant BMDQ. P‐values of the non‐parametric Mann–Whitney test were all 0.05.

Conclusion: It could be concluded that, 3 months after irradiation, the BMD of irradiated alveolar minipig bone was increased, when compared with non‐irradiated alveolar minipig bone. However, the increase was not statistically significant.
Osteotomy and membrane elevation during the maxillary sinus augmentation procedure
Authors: Barone Antonio , Santini Stefano , Marconcini Simone , Giacomelli Luca , Gherlone Enrico , Covani Ugo
Published: March 2008

Objectives: The aim of the present study was to investigate in a randomized‐controlled clinical trial the performance of rotary instruments compared with a piezoelectric device during maxillary sinus floor elevation.

Materials and methods: Thirteen patients who required a bilateral maxillary sinus augmentation for implant–prosthetic rehabilitation were included in this study. A within‐patient control study was carried out. The osteotomy for sinus access was performed on one side of the maxilla using the piezosurgery (test sites) and on the other side using conventional rotary diamond burs (control sites). The parameters recorded were as follows: bony window length (L), bony window height (H), bone thickness (T) and osteotomy area (A) – calculated by multiplying L and H. In addition, the time necessary for the osteotomy and sinus membrane elevation as well as the number of surgical complications were calculated.

Results: The mean length and height of the bone window were similar in both groups. The osteotomy area (A) obtained by multiplying L and H was wider in the control group (151.2 ± 20.4 mm2) compared with the test group (137 ± 24.2 mm2). The time necessary for the osteotomy and the sinus membrane elevation with conventional instruments was 10.2 ± 2.4 min, while with the piezoelectric device it was 11.5 ± 3.8 min. Moreover, membrane perforation occurred in 30% of the maxillary sinuses in the test group and in 23% of the control group. None of the differences observed between the two groups reached a level of significance.

Conclusions: Within the limits of the present study, it may be concluded that piezosurgery and conventional instruments did not show any differences in the clinical parameters investigated for the maxillary sinus floor elevation.