bluuebunny/crossref_metadata_2025 huggingface dataset:
29. WHAT DO ANAL CYTOLOGY RESULTS MEAN?
Authors: Hillman R.
Published: December 2007

Background: Between 1970 and 2000 in Australia, anal cancer rates have increased over fourfold. Furthermore, the prevalence rate of anal cancer in MSM is approximately 35 cases/100�000, comparable to that of cervical cancer in women prior to the introduction of the national cervical screening program. These observations have led to calls for the introduction of targeted anal cytological screening program for MSMs. Our study examined the effectiveness of anal cytological testing in detecting histologically proven high grade anal intraepithelial neoplasia (HGAIN, also known as AIN2 & 3).
Methods: A retrospective case note review of people attending an anal dysplasia clinic from July 2002 to May 2007 was performed. Cytological results of anal swabs were compared to results of biopsies obtained through high resolution anoscopy.
Results: 436 anal cytological results were identified. Of these, 5% were unsatisfactory, 51% showed low grade changes and 44% showed high grade changes. 185 cases were then paired with corresponding histological results.
Analysing the data from the perspective of diagnosing histologically proven HGAIN, anal swab cytological abnormalities revealed a sensitivity of 54% and specificity of 90% for the most recent cytological test and 83% and 39% respectively, when analysed according to most serious cytological result ever.
Conclusions: Our sensitivities of 54-83% and specificities of 39-90% are consistent with those found with cervical cytology, but emphasize the need for caution in their interpretation. However, before any anal cytological screening programs are introduced, it is important to also establish that treatment of any high grade anal dysplasia detected by such screening is of value in preventing progression to cancer.
34. PATTERNS OF CONTRACEPTIVE USE AFTER REPRODUCTIVE EVENTS: FINDINGS FROM THE AUSTRALIAN LONGITUDINAL STUDY OF WOMEN'S HEALTH
Authors: Lucke J. C. , Spallek M.
Published: December 2007

This paper examines changes in young women's contraceptive use over nine years in relation to a range of reproductive life events using longitudinal data from the Australian Longitudinal Study on Women's Health (ALSWH).
Little previous research has examined changes in young women's contraceptive use after significant reproductive or health life events. Some research has examined the reasons that women might discontinue contraceptive use in general and there has been some work investigating contraceptive use after the birth of a child and after the termination of a pregnancy. However other events may also cause a woman to re-evaluate her contraception, for example, the diagnosis of an STD, or having an abnormal pap test.
The Australian Longitudinal Study on Women's Health is a broad-ranging project which examines relationships between many biological, physiological, social and lifestyle factors and women's physical health, emotional well-being, and use of and satisfaction with health services. Women were selected from the Medicare database which includes all citizens and permanent residents using stratified random sampling, with systematic over-sampling of women from rural and remote areas.
This paper presents data from 6716 women who completed a self-report survey in 1996 when they were aged 18-23, and again in 1999, 2002 and 2005. Multinomial analysis is used to explore patterns of contraceptive use before and after events related to pregnancy and birth (pregnancy, live birth, miscarriage and termination of pregnancy) and health (diagnosis with a sexually-transmitted infection and abnormal Pap test) and the factors associated with changes in contraceptive use. The ALSWH provides an exciting opportunity to examine patterns of contraceptive use over time among women of reproductive age.
46. INNOVATION AND DESIGN: IMPROVING CONTACT TRACING IN SEXUAL HEALTH CLINICS
Authors: Edmiston N. , Henry B. , Barker K. , Aitken S.
Published: December 2007

Contact tracing (CT) is an integral part of sexually transmitted infection (STI) management. Although routinely conducted in most sexual health clinics (SHCs), the methods used may vary. To improve CT required novel approaches.
First we audited the outcomes of current contact tracing methods. A major finding of this audit was that while CT was routinely recommended, outcomes were poorly recorded. We developed a sticker to be placed in the charts of clients with a traceable STI. This indicated the number of contacts requiring notification, and how many had been notified and treated at our clinic. This enabled a standardised approach to CT records and improved ability to audit outcomes. It also focused clinicians on the need to ensure followup of CT and to offer assistance when CT had not been done.
Next, a brochure was developed to give to clients when diagnosed with a traceable STI. This brochure mentioned the reasons for contacting patterns, dispelled some myths that have been found in previous studies about telling partners and provided ideas about how to tell partners.
In conjunction with this a SMS was developed, that could be sent to index cases' mobile phones, allowing them to forward the SMS to partners. This was seen as an ideal method for young people who frequently had mobile numbers of past partners but little other contact details. It was also able to be simple and quick.
The next step will be reauditing the CT outcomes once the SMS and brochure are in established use.
50. THE MANAGEMENT OF MEN WITH ACUTE CHLAMYDIA-NEGATIVE NON-GONOCOCCAL URETHRITIS: A LACK OF CONSENSUS AMONG AUSTRALIAN SEXUAL HEALTH PHYSICIANS
Authors: Teague R. , Fairley C. K. , Newton D. , Bradshaw C. , Donovan B. , Bowden F. J. , Cummings R. , Chen M. Y.
Published: December 2007

Objective: In clinical practice, chlamydia-negative non-gonococcal urethritis (NGU) is a common but poorly understood condition. The purpose of this study was to determine how Australian sexual health physicians manage men with this condition.
Methods: In July 2006, a survey was mailed to all members of the Australasian Chapter of Sexual Health Medicine.
Results: Of 166 surveys mailed out, 111 (67%) were returned completed. The majority of sexual health physicians (73%, n�=�81) indicated that they believed that female partners of men with acute chlamydia-negative NGU were at risk of adverse reproductive health outcomes. However, only 19% (n�=�21) routinely tested men with acute NGU for pathogens other than Neisseria gonorrhoeae and Chlamydia trachomatis. Most commonly, this was for M. genitalium (n�=�16). While 68% of respondents believed that M. genitalium was a cause of acute NGU, only 27% had access to testing for this organism. Other pathogens that were sometimes tested for included herpes simplex virus, Trichomonas vaginalis and adenovirus. Over half of sexual health physicians indicated that they would usually initiate notification of female sexual partners of men presenting with acute NGU, even before confirmatory test results were available.
Conclusion: There are substantial differences in how acute, chlamydia-negative NGU is managed by Australian sexual health physicians. In part, these may relate to differences in beliefs around which pathogens are responsible for this condition and the availability of testing for particular pathogens. Notification of female partners is commonplace, even though the underlying cause of urethritis in affected men appears to be poorly defined.
7. THE CHLAMYDIA PROJECT IMPROVING KNOWLEDGE OF, AND TESTING RATES FOR CHLAMYDIA AMONG YOUNG PEOPLE IN A REMOTE ABORIGINAL SETTING
Authors: Dunn C. , Garton L. , Lynch K.
Published: December 2007

The Kimberley region has some of the highest rates of Chlamydia infection in Australia. NCHS obtained funding to initiate and establish a Chlamydia Project aimed at increasing screening rates amongst indigenous youth aged 15 to 30 in the Fitzroy Valley. Population for the Valley is approximately 3000, predominately Aboriginal, covering more than 40 remote communities and the town of Fitzroy Crossing. The community has a strong belief in traditional values therefore observation of cultural protocols is paramount, especially when working in the area of sexual health. This can present challenges when setting up a sexual health program that is culturally appropriate, accepted and sustainable.
The aim of the project is to encourage young people to attend for STI screening when they are asymptomatic. The project will also endeavour to increase awareness of Chlamydia and other sexual health issues relevant to the age group.
Methods used, include setting up screening clinics in town and remote communities, involving young people in making decisions about how the clinics are run, holding Feel Good Nights that promote discussion and information sharing about sexual health, peer education and encouraging young people to participate in resource production.
Anecdotally, results so far have shown a greater number of young people are accessing sexual health services and there is an increase in knowledge of Chlamydia and sexual health in general amongst the target population. This project will run until May 2008. This paper will present the progress of the project so far, and some of the highlights and challenges of setting up a sexual health program in a remote community setting.
Hematopoietic prostaglandin D2synthase controls the onset and resolution of acute inflammation through PGD2and 15-deoxyΔ12–14PGJ2
Authors: Rajakariar Ravindra , Hilliard Mark , Lawrence Toby , Trivedi Seema , Colville-Nash Paul , Bellingan Geoff , Fitzgerald Desmond , Yaqoob Muhammad M. , Gilroy Derek W.
Published: December 2007

Hematopoietic prostaglandin D2synthase (hPGD2S) metabolizes cyclooxygenase (COX)-derived PGH2to PGD2and 15-deoxyΔ12–14PGJ2(15d-PGJ2). Unlike COX, the role of hPGD2S in host defense is ambiguous. PGD2can be either pro- or antiinflammatory depending on disease etiology, whereas the existence of 15d-PGJ2and its relevance to pathophysiology remain controversial. Herein, studies on hPGD2S KO mice reveal that 15d-PGJ2is synthesized in a self-resolving peritonitis, detected by using liquid chromatography–tandem MS. Together with PGD2working on its DP1 receptor, 15d-PGJ2controls the balance of pro- vs. antiinflammatory cytokines that regulate leukocyte influx and monocyte-derived macrophage efflux from the inflamed peritoneal cavity to draining lymph nodes leading to resolution. Specifically, inflammation in hPGD2S KOs is more severe during the onset phase arising from a substantial cytokine imbalance resulting in enhanced polymorphonuclear leukocyte and monocyte trafficking. Moreover, resolution is impaired, characterized by macrophage and surprisingly lymphocyte accumulation. Data from this work place hPGD2S at the center of controlling the onset and the resolution of acute inflammation where it acts as a crucial checkpoint controller of cytokine/chemokine synthesis as well as leukocyte influx and efflux. Here, we provide definitive proof that 15d-PGJ2is synthesized during mammalian inflammatory responses, and we highlight DP1 receptor activation as a potential antiinflammatory strategy.
Consequences of localized frustration for the folding mechanism of the IM7 protein
Authors: Sutto Ludovico , Lätzer Joachim , Hegler Joseph A. , Ferreiro Diego U. , Wolynes Peter G.
Published: December 2007

In the laboratory, IM7 has been found to have an unusual folding mechanism in which an “on-pathway” intermediate with nonnative interactions is formed. We show that this intermediate is a consequence of an unusual cluster of highly frustrated interactions in the native structure. This cluster is involved in the binding of IM7 to its target, Colicin E7. Redesign of residues in this cluster to eliminate frustration is predicted by simulations to lead to faster folding without the population of an intermediate ensemble.
Single Motherhood Versus Poor Partner Relationship: Outcomes for Antenatal Mental Health
Authors: Bilszta Justin L.C. , Tang Melissa , Meyer Denny , Milgrom Jeannette , Ericksen Jennifer , Buist Anne E.
Published: December 2007

Objective: In the transition to parenthood, lack of social support significantly impacts on maternal mood. This paper compares the influence of single-mother status and level of partner support in a partnered relationship, on antenatal emotional health.

Methods: Antenatal demographic, psychosocial and mental health data, as determined by Edinburgh Postnatal Depression Scale (EPDS) score, were collected from 1578 women. The association between these variables, and marital status, was investigated using logistic regression.

Results: Sixty-two women (3.9%) were identified as single/unpartnered. Elevated EPDS scores (>12) were found in 15.2% (240/1578) of the total cohort and 25.8% (16/62) of the single/unpartnered women. EPDS scores were significantly lower for single/unpartnered women than for women with unsupportive partners (8.9±5.3 vs 11.9±6.5, p<0.001). Compared to the partnered cohort, single/unpartnered women were more likely to have experienced ≥2 weeks of depression before the current pregnancy (p<0.05), a previous psychopathology (p<0.001), emotional problems during the current pregnancy (p<0.01) and major life events in the last year (p<0.01). Binary logistic regression modelling to predict antenatal EPDS scores suggests that this is mediated by previous psychiatric history (p<0.001) and emotional problems during pregnancy (p=0.02).

Conclusion: Women in a partnered-relationship with poor partner-derived support were at an increased risk of elevated antenatal EPDS scores compared to single/unpartnered women. A previous history of depression and current emotional problems, rather than single mother status, were significant risk factors for elevated EPDS scores. The present study reiterates the contribution of psychosocial risk factors as important mediators of antenatal emotional health.
Humor and Laughter May Influence Health IV. Humor and Immune Function
Authors: Bennett Mary Payne , Lengacher Cecile
Published: December 2007

This is the final article in a four part series reviewing the influence of humor and laughter on physiological and psychological well‐being. This final article reviews the evidence for the effect of sense of humor, exposure to a humor stimulus and laughter on various immune system components, with a focus on the effects of laughter on natural killer cell cytotoxicity.
Retrospective multicentre study of the new minimally invasive mesh repair devices for pelvic organ prolapse
Authors: Abdel‐fattah M , Ramsay I ,   West of Scotland Study Group
Published: December 2007

Objectives  To assess the complications and short‐term outcomes of prolapse repair mesh devices used in the management of female pelvic organ prolapse (POP).

Design  Retrospective cohort study.

Setting  Multicentre study involving a tertiary referral urogynaecology unit and two district general hospitals.

Population  329 women who underwent surgical management of prolapse with various prolapse repair mesh devices in the period between January 2005 and December 2006.

Methods  Women were identified from theatre records. An independent clinician performed a case notes review during the period March to May 2007.

Main Outcome Measures  Complication rates and the short‐term cure at 3‐month follow‐up (defined as ≤stage I prolapse on the POP‐Q or Baden Walker scoring systems).

Results  A total of 289 women were included: 219 (76%) used the Gynecare prolapse repair mesh devices, while 70 women (24%) used the American Medical Systems prolapse repair mesh devices. Operative complications included: bladder injury (1.6%), rectal injury (1.1%) and two women with serious vascular injuries. Postoperative complications included: buttock pain (5.2%), vaginal erosion (10%), one woman with bladder erosion and two women (0.7%) with serious infection, leading to necrotising fasciitis in one woman. Short‐term cure rates in different groups varied from 94 to 100%, depending on vaginal compartment and device used. In total 15 women (5%) had persistent prolapse at 3‐month follow up.

Conclusion  The new prolapse repair mesh devices demonstrate excellent short‐term cure and low morbidity rates. However, some complications are serious and require highly specialised management. Rigorous evaluation by means of independent, controlled studies is urgently required.
Social inequalities in preterm birth in Scotland 1980–2003: findings from an area‐based measure of deprivation
Authors: Gray R , Bonellie SR , Chalmers J , Greer I , Jarvis S , Williams C
Published: December 2007

Objective  The preterm birth rate in Scotland has been increasing in recent years. Although preterm birth rates show a social gradient, it is unclear how this gradient has been affected by the overall increase. We examined time trends in singleton live preterm birth rates in relation to area‐based socio‐economic indicators.

Design  Population‐based retrospective cohort study.

Setting  Scotland.

Participants  All singleton live births delivered in Scottish hospitals between 1980 and 2003 (n= 1 423 993).

Main outcome measures  Singleton live preterm birth rates in each deprivation quintile were derived. Subgroup analyses of those born moderately preterm (32–36 weeks), very preterm (28–31 weeks) and extremely preterm (24–27 weeks) were performed.

Results  The rate of singleton live preterm births increased from 49.7 per 1000 live births in the 5‐year period 1980–84 to 56.1 per 1000 in the 4‐year period 2000–03, a relative increase of 12.9%. A marked social gradient was apparent at all time periods: relative indices of inequality were 1.63 (95% CI 1.38–1.92) in 1980–84 and 1.55 (1.44–1.66) in 2000–03. Similar social gradients existed for all gestational age subgroups. Smoking status at first antenatal contact and increased obstetric intervention, possibly reflecting improvements in fetal monitoring and neonatal care, appeared to explain some but not all the social gradient.

Conclusions  Social inequalities in preterm birth were apparent in Scotland between 1980 and 2003. In addition to helping pregnant women to stop smoking, other means to reduce social inequalities are required.
Computer‐aided detection of interstitial abnormalities in chest radiographs using a reference standard based on computed tomography
Authors: Arzhaeva Yulia , Prokop Mathias , Tax David M. J. , De Jong Pim A. , Schaefer–Prokop Cornelia M. , van Ginneken Bram
Published: December 2007

A computer‐aided detection (CAD) system is presented for the localization of interstitial lesions in chest radiographs. The system analyzes the complete lung fields using a two‐class supervised pattern classification approach to distinguish between normal texture and texture affected by interstitial lung disease. Analysis is done pixel‐wise and produces a probability map for an image where each pixel in the lung fields is assigned a probability of being abnormal. Interstitial lesions are often subtle and ill defined on x‐rays and hence difficult to detect, even for expert radiologists. Therefore a new, semiautomatic method is proposed for setting a reference standard for training and evaluating the CAD system. The proposed method employs the fact that interstitial lesions are more distinct on a computed tomography (CT) scan than on a radiograph. Lesion outlines, manually drawn on coronal slices of a CT scan of the same patient, are automatically transformed to corresponding outlines on the chest x‐ray, using manually indicated correspondences for a small set of anatomical landmarks. For the texture analysis, local structures are described by means of the multiscale Gaussian filter bank. The system performance is evaluated with ROC analysis on a database of digital chest radiographs containing 44 abnormal and 8 normal cases. The best performance is achieved for the linear discriminant and support vector machine classifiers, with an area under the ROC curve of 0.78. Separate ROC curves are built for classification of abnormalities of different degrees of subtlety versus normal class. Here the best performance in terms of is 0.90 for differentiation between obviously abnormal and normal pixels. The system is compared with two human observers, an expert chest radiologist and a chest radiologist in training, on evaluation of regions. Each lung field is divided in four regions, and the reference standard and the probability maps are converted into region scores. The system performance does not significantly differ from that of the observers, when the perihilar regions are excluded from evaluation, and reaches for the system, with for both observers.
MicroRT—Small animal conformal irradiator
Authors: Stojadinovic S. , Low D. A. , Hope A. J. , Vicic M. , Deasy J. O. , Cui J. , Khullar D. , Parikh P. J. , Malinowski K. T. , Izaguirre E. W. , Mutic S. , Grigsby P. W.
Published: December 2007

A novel small animal conformal radiation therapy system has been designed and prototyped: MicroRT. The microRT system integrates multimodality imaging, radiation treatment planning, and conformal radiation therapy that utilizes a clinical isotope high dose rate source as the radiation source (teletherapy). A multiparameter dose calculation algorithm based on Monte Carlo dose distribution simulations is used to efficiently and accurately calculate doses for treatment planning purposes. A series of precisely machined tungsten collimators mounted onto a cylindrical collimator assembly is used to provide the radiation beam portals. The current design allows a source‐to‐target distance range of 1–8 cm at four beam angles: (beam oriented down), , , and . The animal is anesthetized and placed in an immobilization device with built‐in fiducial markers and scanned using a computed tomography, magnetic resonance, or positron emission tomography scanner prior to irradiation. Treatment plans using up to four beam orientations are created utilizing a custom treatment planning system—microRTP. A three‐axis computer‐controlled stage that supports and accurately positions the animals is programmed to place the animal relative to the radiation beams according to the microRTP plan. The microRT system positioning accuracy was found to be submillimeter. The radiation source is guided through one of four catheter channels and placed in line with the tungsten collimators to deliver the conformal radiation treatment. The microRT hardware specifications, the accuracy of the treatment planning and positioning systems, and some typical procedures for radiobiological experiments that can be performed with the microRT device are presented.
Phantom experiments to improve parathyroid lesion detection
Authors: Nichols Kenneth J. , Tronco Gene G. , Tomas Maria B. , Kunjummen Biju D. , Siripun Lisa , Rini Josephine N. , Palestro Christopher J.
Published: December 2007

This investigation tested the hypothesis that visual analysis of iteratively reconstructed tomograms by ordered subset expectation maximization (OSEM) provides the highest accuracy for localizing parathyroid lesions using ‐sestamibi SPECT data. From an Institutional Review Board approved retrospective review of 531 patients evaluated for parathyroid localization, image characteristics were determined for 85 ‐sestamibi SPECT studies originally read as equivocal (EQ). Seventy‐two plexiglas phantoms using cylindrical simulated lesions were acquired for a clinically realistic range of counts (mean simulated lesion counts of ) and target‐to‐background ratios () to determine an optimal filter for OSEM. Two experienced nuclear physicians graded simulated lesions, blinded to whether chambers contained radioactivity or plain water, and two observers used the same scale to read all phantom and clinical SPECT studies, blinded to pathology findings and clinical information. For phantom data and all clinical data, analyses were not statistically different for OSEM versus FB, but visual readings were significantly more accurate than ( versus , ) for OSEM processing, and OSEM was significantly more accurate than FB for visual readings ( versus , ). These data suggest that visual analysis of iteratively reconstructed MIBI tomograms should be incorporated into imaging protocols performed to localize parathyroid lesions.
Characterization of optically stimulated luminescent dosimeters, OSLDs, for clinical dosimetric measurements
Authors: Jursinic Paul A.
Published: December 2007

Optically stimulated luminescent dosimeters, OSLDs, are plastic disks infused with aluminum oxide doped with carbon . These disks are encased in a light‐tight plastic holder. Crystals of when exposed to ionizing radiation store energy that is released as luminescence (420 nm) when the OSLD is illuminated with stimulation light (540 nm). The intensity of the luminescence depends on the dose absorbed by the OSLD and the intensity of the stimulation light. OSLDs used in this work were InLight/OSL Dot dosimeters, which were read with a MicroStar reader (Landauer, Inc., Glenwood, IL). The following are dosimetric properties of the OSLD that were determined: After a single irradiation, repeated readings cause the signal to decrease by per reading; the signal could be discharged by greater than by illuminating them for more than 45 s with a 150 W tungsten‐halogen light; after irradiation there was a transient signal that decayed with a 0.8 min halftime; after the transient signal decay the signal was stable for days; repeated irradiations and readings of an individual OSLD gave a signal with a coefficient of variation of ; the dose sensitivity of OSLDs from a batch of detectors has a coefficient of variation of , response was linear with absorbed dose over a test range of 1–300 cGy; above 300 cGy a small supra‐linear behavior occurs; there was no dose‐per‐pulse dependence over a 388‐fold range; there was no dependence on radiation energy or mode for 6 and 15 MV x rays and 6–20 MeV electrons; for Ir‐192 gamma rays OSLD had higher sensitivity; the dose sensitivity was unchanged up to an accumulated dose of 20 Gy and thereafter decreased by per 10 Gy of additional accumulated dose; dose sensitivity was not dependent on the angle of incidence of radiation; the OSLD in its light‐tight case has an intrinsic buildup of ; dose sensitivity of the OSLD was not dependent on temperature at the time of irradiation in the range of 10–. The clinical use of OSLDs for in vivo dosimetric measurements is shown to be feasible.
A directional distance aided method for medical image segmentation
Authors: Zhuge Feng , Sun Shaohua , Rubin Geoffrey , Napel Sandy
Published: December 2007

A challenging problem in image segmentation is preventing boundary leakage through poorly resolved edges because not enough local information can be provided along them. In this article, we propose a new directional distance aided image segmentation method, formulated under the level set framework, to prevent the leakage. At each evolution step, the zero level set is extracted and smoothed. For each point on the zero level set, a new directional distance (DD) term, defined as the vector starting from itself and pointing to its counterpart on the smoothed version of the zero level set, is calculated to measure its “degree of protrusion.” The evolution speed of the points that are considered to be protruding out will be penalized. Other terms, e.g., curvature and gradient terms and user specified constraints, are used along with the DD term to influence the level set evolution. Our smoothing technique augments traditional Gaussian smoothing with a new antishrinkage operation. The novelty of our method is that the DD term does not depend on intensity or gradient boundaries to regulate the regional shape and, therefore, help prevent leakage and the method incorporates vertex‐based curve/surface smoothing into curve evolution under the level set framework. Experimental results show that the new DDA method achieves promising results and reasonable stability in segmenting simulated objects as well as abdominal aortic aneurysms in computed tomography (CT) angiograms, in both 2D and 3D, by preventing leakage into adjacent structures while preserving local shape details.
Scaling of EPR spectral‐spatial images with size of sample: Images of a sample greater than 5 cm in linear dimension
Authors: Ahn Kang‐Hyun , Subramanian V. S. , Halpern Howard J.
Published: December 2007

The authors have obtained spectral‐spatial EPR images of a phantom significantly larger than those previously obtained. Images of a homogeneous phantom 4.2 cm in diameter and 6.5 cm in length with equivalent to that used for smaller samples give a similar linewidth resolution both with linewidth population distributions of width . Spatial resolution appeared to have modest degradation. Images of the large homogeneous phantom provide maps of the magnetic field of a partially shimmed magnet.
Creation and establishment of a respiratory liver motion simulator for liver interventions
Authors: Müller S. A. , Maier‐Hein L. , Mehrabi A. , Pianka F. , Rietdorf U. , Wolf I. , Grenacher L. , Richter G. , Gutt C. N. , Schmidt J. , Meinzer H. P. , Schmied B. M.
Published: December 2007

Image‐guided surgery and navigation have resulted from convergent developments in radiology, teletransmission, and computer science and are well‐established procedures in the surgical routine in orthopedic, neurosurgery, and head‐and‐neck surgery. In abdominal surgery, however, these tools have gained little attraction so far. The inability to transfer the methodology from orthopedic or neurosurgery is mainly a result of intraoperative organ movement and shifting. To practice and establish navigated interventions in the liver, a custom‐designed respiratory liver motion simulator was built which models the human torso and is easy to recreate. To simulate breathing motion, an explanted porcine or human liver is mounted to the diaphragm model of the simulator, and a lung ventilator causes a periodic movement of the liver along the craniocaudal axis. Additionally, the liver can be connected to a circulating pump device which simulates hepatic perfusion and provides real surgical options to establish navigated interventions and simulate management of possible complications. Respiratory motion caused by the simulator was evaluated with an optical tracking system and it was shown that in vitro movement and deformation of a liver mounted to the device are similar to the liver movements in human or porcine bodies. Based on the tests, it is concluded that the novel respiratory liver motion simulator is suitable for in vitro evaluation of navigated systems and interventional and surgical procedures.
Automatic 3D‐to‐2D registration for CT and dual‐energy digital radiography for calcification detection
Authors: Chen Xiang , Gilkeson Robert C. , Fei Baowei
Published: December 2007

We are investigating three‐dimensional (3D) to two‐dimensional (2D) registration methods for computed tomography (CT) and dual‐energy digital radiography (DEDR). CT is an established tool for the detection of cardiac calcification. DEDR could be a cost‐effective alternative screening tool. In order to utilize CT as the “gold standard” to evaluate the capability of DEDR images for the detection and localization of calcium, we developed an automatic, intensity‐based 3D‐to‐2D registration method for 3D CT volumes and 2D DEDR images. To generate digitally reconstructed radiography (DRR) from the CT volumes, we developed several projection algorithms using the fast shear‐warp method. In particular, we created a Gaussian‐weighted projection for this application. We used normalized mutual information (NMI) as the similarity measurement. Simulated projection images from CT values were fused with the corresponding DEDR images to evaluate the localization of cardiac calcification. The registration method was evaluated by digital phantoms, physical phantoms, and clinical data sets. The results from the digital phantoms show that the success rate is 100% with a translation difference of less than and a rotation difference of less than 0.2°. For physical phantom images, the registration accuracy is . Color overlay and 3D visualization of clinical images show that the two images registered well. The NMI values between the DRR and DEDR images improved from before registration to after registration. Registration errors measured from anatomic markers decreased from before registration to after registration. Our results show that the automatic 3D‐to‐2D registration is accurate and robust. This technique can provide a useful tool for correlating DEDR with CT images for screening coronary artery calcification.
An absorbed dose to water standard for HDR brachytherapy sources based on water calorimetry: Numerical and experimental proof‐of‐principle
Authors: Sarfehnia Arman , Stewart Kristin , Seuntjens Jan
Published: December 2007

Water calorimetry is an established technique for absorbed dose to water measurements in external beams. In this paper, the feasibility of direct absorbed dose measurements for high dose rate (HDR) iridium‐192 sources using water calorimetry is established. Feasibility is determined primarily by a balance between the need to obtain sufficient signal to perform a reproducible measurement, the effect of heat loss on the measured signal, and the positioning uncertainty affecting the source‐detector distance. The heat conduction pattern generated in water by the Nucletron microSelectron‐HDR brachytherapy source was simulated using COMSOL MULTIPHYSICSTM software. Source heating due to radiation self‐absorption was calculated using EGSnrcMP. A heat‐loss correction was calculated as the ratio of the temperature rise under ideal conditions to temperature rise under realistic conditions. The calorimeter setup used a parallel‐plate calorimeter vessel of 79 mm diameter and 1.12 mm thick front and rear glass windows located 24 mm apart. Absorbed dose was measured with two sources with nominal air kerma strengths of 38 000 and 21 000 U, at source‐detector separations ranging from 24.7 to 27.6 mm and irradiation times of 36.0 to 80.0 s. The preliminary measured dose rate per unit air kerma strength of compares well with the TG‐43 derived . This work shows that combined dose uncertainties of significantly less than can be achieved with only modest modifications of current water calorimetry techniques and instruments. This work forms the basis of a potential future absolute dose to water standard for HDR brachytherapy.
Coronal Transverse Magnetohydrodynamic Waves in a Solar Prominence
Authors: Okamoto T. J. , Tsuneta S. , Berger T. E. , Ichimoto K. , Katsukawa Y. , Lites B. W. , Nagata S. , Shibata K. , Shimizu T. , Shine R. A. , Suematsu Y. , Tarbell T. D. , Title A. M.
Published: December 2007

Solar prominences are cool 10
4
kelvin plasma clouds supported in the surrounding 10
6
kelvin coronal plasma by as-yet-undetermined mechanisms. Observations from Hinode show fine-scale threadlike structures oscillating in the plane of the sky with periods of several minutes. We suggest that these represent Alfvén waves propagating on coronal magnetic field lines and that these may play a role in heating the corona.
Stabilizing Isopeptide Bonds Revealed in Gram-Positive Bacterial Pilus Structure
Authors: Kang Hae Joo , Coulibaly Fasséli , Clow Fiona , Proft Thomas , Baker Edward N.
Published: December 2007

Many bacterial pathogens have long, slender pili through which they adhere to host cells. The crystal structure of the major pilin subunit from the Gram-positive human pathogen
Streptococcus pyogenes
at 2.2 angstroms resolution reveals an extended structure comprising two all-β domains. The molecules associate in columns through the crystal, with each carboxyl terminus adjacent to a conserved lysine of the next molecule. This lysine forms the isopeptide bonds that link the subunits in native pili, validating the relevance of the crystal assembly. Each subunit contains two lysine-asparagine isopeptide bonds generated by an intramolecular reaction, and we find evidence for similar isopeptide bonds in other cell surface proteins of Gram-positive bacteria. The present structure explains the strength and stability of such Gram-positive pili and could facilitate vaccine development.
Slipping Magnetic Reconnection in Coronal Loops
Authors: Aulanier Guillaume , Golub Leon , DeLuca Edward E. , Cirtain Jonathan W. , Kano Ryouhei , Lundquist Loraine L. , Narukage Noriyuki , Sakao Taro , Weber Mark A.
Published: December 2007

Magnetic reconnection of solar coronal loops is the main process that causes solar flares and possibly coronal heating. In the standard model, magnetic field lines break and reconnect instantaneously at places where the field mapping is discontinuous. However, another mode may operate where the magnetic field mapping is continuous but shows steep gradients: The field lines may slip across each other. Soft x-ray observations of fast bidirectional motions of coronal loops, observed by the Hinode spacecraft, support the existence of this slipping magnetic reconnection regime in the Sun's corona. This basic process should be considered when interpreting reconnection, both on the Sun and in laboratory-based plasma experiments.
Continuous Plasma Outflows from the Edge of a Solar Active Region as a Possible Source of Solar Wind
Authors: Sakao Taro , Kano Ryouhei , Narukage Noriyuki , Kotoku Jun'ichi , Bando Takamasa , DeLuca Edward E. , Lundquist Loraine L. , Tsuneta Saku , Harra Louise K. , Katsukawa Yukio , Kubo Masahito , Hara Hirohisa , Matsuzaki Keiichi , Shimojo Masumi , Bookbinder Jay A. , Golub Leon , Korreck Kelly E. , Su Yingna , Shibasaki Kiyoto , Shimizu Toshifumi , Nakatani Ichiro
Published: December 2007

The Sun continuously expels a huge amount of ionized material into interplanetary space as the solar wind. Despite its influence on the heliospheric environment, the origin of the solar wind has yet to be well identified. In this paper, we report Hinode X-ray Telescope observations of a solar active region. At the edge of the active region, located adjacent to a coronal hole, a pattern of continuous outflow of soft-x-ray–emitting plasmas was identified emanating along apparently open magnetic field lines and into the upper corona. Estimates of temperature and density for the outflowing plasmas suggest a mass loss rate that amounts to ∼1/4 of the total mass loss rate of the solar wind. These outflows may be indicative of one of the solar wind sources at the Sun.
The Equatorial Ridges of Pan and Atlas: Terminal Accretionary Ornaments?
Authors: Charnoz Sébastien , Brahic André , Thomas Peter C. , Porco Carolyn C.
Published: December 2007

In the outer regions of Saturn's main rings, strong tidal forces balance gravitational accretion processes. Thus, unusual phenomena may be expected there. The Cassini spacecraft has recently revealed the strange “flying saucer” shape of two small satellites, Pan and Atlas, located in this region, showing prominent equatorial ridges. The accretion of ring particles onto the equatorial surfaces of already-formed bodies embedded in the rings may explain the formation of the ridges. This ridge formation process is in good agreement with detailed Cassini images showing differences between rough polar and smooth equatorial terrains. We propose that Pan and Atlas ridges are kilometers-thick “ring-particle piles” formed after the satellites themselves and after the flattening of the rings but before the complete depletion of ring material from their surroundings.
Sensing X Chromosome Pairs Before X Inactivation via a Novel X-Pairing Region of the
Xic
Authors: Augui S. , Filion G. J. , Huart S. , Nora E. , Guggiari M. , Maresca M. , Stewart A. F. , Heard E.
Published: December 2007

Mammalian dosage compensation involves silencing of one of the two X chromosomes in females and is controlled by the X-inactivation center (
Xic
). The
Xic
, which includes
Xist
and its antisense transcription unit
Tsix/Xite
, somehow senses the number of X chromosomes and triggers
Xist
up-regulation from one of the two X chromosomes in females. We found that a segment of the mouse
Xic
lying several hundred kilobases upstream of
Xist
brings the two
Xic
s together before the onset of X inactivation. This region can autonomously drive
Xic
trans-interactions even as an ectopic single-copy transgene. Its introduction into male embryonic stem cells is strongly selected against, consistent with a possible role in trans-activating
Xist
. We propose that homologous associations driven by this novel X-pairing region (
Xpr
) of the
Xic
enable a cell to sense that more than one X chromosome is present and coordinate reciprocal
Xist/Tsix
expression.
Molecular Characterization of a Novel Fastidious Mycobacterium Causing Lepromatous Lesions of the Skin, Subcutis, Cornea, and Conjunctiva of Cats Living in Victoria, Australia
Authors: Fyfe J. A. , McCowan C. , O'Brien C. R. , Globan M. , Birch C. , Revill P. , Barrs V. R. D. , Wayne J. , Hughes M. S. , Holloway S. , Malik R.
Published: December 2007

Between 1999 and 2006, 15 cats were diagnosed with disease attributable to a novel mycobacterial species. The infections consisted of granulomatous lesions in the skin, subcutis, and ocular or periocular tissues with an indolent but progressive clinical course. Lesions typically were found in facial regions or on the distal limbs. Cats of all ages and both sexes were affected. Infections often were challenging to treat, although they could be cured using surgery in concert with combination antimicrobial therapy. Microscopically, lesions were granulomatous to pyogranulomatous and contained numerous acid-fast bacilli. Scanty cultures of the causal microorganisms occasionally could be obtained in mycobacterial broth, but subculture to solid media failed. When cultures were not available, DNA was extracted from fresh tissue, lyophilized material, and formalin-fixed, paraffin-embedded tissues from lesions. PCR amplification of the 5′ end of the 16S rRNA gene and regions within four additional loci (ITS1,
hsp65
,
rpoB
, and
sodA
) was performed with various efficiencies using mycobacterial primers. Nucleotide sequences were unique for each locus tested. Nucleotide sequences obtained from individual cases were identical for each locus for which the amplification was successful. Phylogenetic analysis performed using concatenated partial 16S rRNA and
hsp65
gene sequences indicated that this novel mycobacterial species from Victoria is a member of the
Mycobacterium simiae
-related group, taxonomically related to the mycobacterium causing leproid granulomas in dogs throughout the world. Based on the clustering of cases, we refer to this novel species as
Mycobacterium
sp. strain Tarwin.
Development of a Species-Specific
fur
Gene-Based Method for Identification of the
Burkholderia cepacia
Complex
Authors: Lynch Karlene H. , Dennis Jonathan J.
Published: December 2007

Burkholderia
is an important bacterial genus with a complex taxonomy that contains species of both ecological and pathogenic importance, including nine closely related species collectively termed the
Burkholderia cepacia
complex (BCC). Unfortunately, 16S rRNA gene analysis has proven to be not sensitive enough to discriminate between species of the BCC. Alternative species identification strategies such as
recA
-based PCR followed by restriction fragment length polymorphism analysis, although initially useful, have proven to be inaccurate with the increasing species diversity of the BCC.
recA
gene sequence analysis is more discriminatory and corroborates other biochemical and polyphasic means of taxonomic differentiation. However, it is limited by the fact that certain BCC species are subdivided into discrete
recA
sequence subgroups that may confuse clinical diagnoses. In this study, an effective approach is described for the rapid differentiation of BCC species from both environmental and clinical sources by means of a single-locus sequencing and PCR assay using
fur
as a target gene that provides sequence phylogenies that are species specific and, with few exceptions, not divided into subspecies clusters. This assay is specific and can be used to correctly determine the species status of BCC strains tested following sequencing and amplification of the
fur
gene by both general and species-specific primers. Based on our results, this typing strategy is simpler than and as sensitive as established tests currently in use clinically. This assay is useful for the rapid, definitive identification of all nine current BCC species and potentially novel species groups.
Multilocus Sequence Typing Reveals that the Population Structure of
Candida dubliniensis
Is Significantly Less Divergent than That of
Candida albicans
Authors: McManus Brenda A. , Coleman David C. , Moran Gary , Pinjon Emmanuelle , Diogo Dorothée , Bougnoux Marie-Elisabeth , Borecká-Melkusova Silvia , Bujdákova Helena , Murphy Philip , d'Enfert Christophe , Sullivan Derek J.
Published: December 2007

The pathogenic yeast
Candida dubliniensis
is phylogenetically very closely related to
Candida albicans
, and both species share many phenotypic and genetic characteristics. DNA fingerprinting using the species-specific probe Cd25 and sequence analysis of the internal transcribed spacer (ITS) region of the ribosomal gene cluster previously showed that
C. dubliniensis
is comprised of three major clades comprising four distinct ITS genotypes. Multilocus sequence typing (MLST) has been shown to be very useful for investigating the epidemiology and population biology of
C. albicans
and has identified many distinct major and minor clades. In the present study, we used MLST to investigate the population structure of
C. dubliniensis
for the first time. Combinations of 10 loci previously tested for MLST analysis of
C. albicans
were assessed for their discriminatory ability with 50 epidemiologically unrelated
C. dubliniensis
isolates from diverse geographic locations, including representative isolates from the previously identified three Cd25-defined major clades and the four ITS genotypes. Dendrograms created by using the unweighted pair group method with arithmetic averages that were generated using the data from all 10 loci revealed a population structure which supports that previously suggested by DNA fingerprinting and ITS genotyping. The MLST data revealed significantly less divergence within the
C. dubliniensis
population examined than within the
C. albicans
population. These findings show that MLST can be used as an informative alternative strategy for investigating the population structure of
C. dubliniensis
. On the basis of the highest number of genotypes per variable base, we recommend the following eight loci for MLST analysis of
C. dubliniensis
: Cd
AAT1b
, Cd
ACC1
, Cd
ADP1
, Cd
MPIb
, Cd
RPN2
, Cd
SYA1
, exCd
VPS13
, and exCd
ZWF1b
, where “Cd” indicates
C. dubliniensis
and “ex” indicates extended sequence.