OrgaSegment: deep-learning based organoid segmentation to quantify CFTR dependent fluid secretion

Epithelial ion and fluid transport studies in patient-derived organoids (PDOs) are increasingly being used for preclinical studies, drug development and precision medicine applications. Epithelial fluid transport properties in PDOs can be measured through visual changes in organoid (lumen) size. Such organoid phenotypes have been highly instrumental for the studying of diseases, including cystic fibrosis (CF), which is characterized by genetic mutations of the CF transmembrane conductance regulator (CFTR) ion channel. Here we present OrgaSegment, a MASK-RCNN based deep-learning segmentation model allowing for the segmentation of individual intestinal PDO structures from bright-field images. OrgaSegment recognizes spherical structures in addition to the oddly-shaped organoids that are a hallmark of CF organoids and can be used in organoid swelling assays, including the new drug-induced swelling assay that we show here. OrgaSegment enabled easy quantification of organoid swelling and could discriminate between organoids with different CFTR mutations, as well as measure responses to CFTR modulating drugs. The easy-to-apply label-free segmentation tool can help to study CFTR-based fluid secretion and possibly other epithelial ion transport mechanisms in organoids.

Workplace oral health promotion activities among community-aged care workers: A qualitative exploration

BACKGROUND

The workplace is an ideal-and priority-setting for health promotion activities. Developing and implementing workplace health promotion interventions, including oral health promotion activities, can help create health-supporting workplace environments.

OBJECTIVE

To pilot workplace oral health promotion activities among staff working in the aged care sector, report their impact and explore participants' views on the factors that contribute to participation and effectiveness.

METHODS

This study comprised three phases: (i) the development and face validation of the resources, (ii) a 3-h educational session and (iii) five interview sessions with participants 4-6 weeks following the education session. The recorded interviews were transcribed verbatim and analysed thematically.

RESULTS

Eleven community-aged care workforce were invited to five feedback sessions. Ten participants were female and ranged in age from 18 to 64. All participants gave favourable comments about the content and delivery of the training session and accompanying resources. The participants felt that the benefits of WOHP include improved staff knowledge, awareness and oral care routine, the ability to share (and put into practice) the gained knowledge and information with their dependants, a lower risk of having poor oral health that adversely affects their well-being and work tasks, and potentially beneficial impacts on the organization's staff roster. Their attendance in the WOHP was facilitated by being paid to attend and scheduling the sessions during work time. Future WOHP suggestions include the possibility of a one-stop dental check-up at the workplace or staff dental care discounts from local dental practitioners and combining oral health with other health promotion activities.

CONCLUSIONS

Planning and implementing WOHP was deemed acceptable and feasible in this study context and successfully achieved short-term impacts among community-aged care workers. Appropriate times and locations, organizational arrangements and a variety of delivery options contributed to successful programme planning and implementation.

Active mesh and neural network pipeline for cell aggregate segmentation

Segmenting cells within cellular aggregates in 3D is a growing challenge in cell biology due to improvements in capacity and accuracy of microscopy techniques. Here, we describe a pipeline to segment images of cell aggregates in 3D. The pipeline combines neural network segmentations with active meshes. We apply our segmentation method to cultured mouse mammary gland organoids imaged over 24 h with oblique plane microscopy, a high-throughput light-sheet fluorescence microscopy technique. We show that our method can also be applied to images of mouse embryonic stem cells imaged with a spinning disc microscope. We segment individual cells based on nuclei and cell membrane fluorescent markers, and track cells over time. We describe metrics to quantify the quality of the automated segmentation. Our segmentation pipeline involves a Fiji plugin that implements active mesh deformation and allows a user to create training data, automatically obtain segmentation meshes from original image data or neural network prediction, and manually curate segmentation data to identify and correct mistakes. Our active meshes-based approach facilitates segmentation postprocessing, correction, and integration with neural network prediction.

Openness to church-based firearm safety interventions among Protestant Christian firearm owners

OBJECTIVES

Protestant Christians are more likely to own firearms and not store them locked/unloaded compared to those from other religions. This study examines how Protestant Christians view the relationship between their religious and firearm beliefs and how that informs openness to church-based firearm safety interventions.

STUDY DESIGN

Grounded theory analysis of 17 semi-structured interviews with Protestant Christians.

METHODS

Interviews, conducted August-October 2020, focused on firearms owned, carrying/discharge/storage behaviors, Christian belief compatibility with firearm ownership, and openness to church-based firearm safety interventions. Audio-recorded interviews were transcribed verbatim and analyzed using grounded theory techniques.

RESULTS

Participant perspectives varied on firearm ownership motivations and compatibility of Christian values with firearm ownership. Variation in these themes and in openness to church-based firearm safety interventions resulted in clustering of participants into three groups. Group 1 owned firearms for collecting/sporting purposes and intricately connected their Christian identity with firearm ownership, but they were not open to intervention due to perceived high firearm proficiency. Group 2 did not connect their Christian identity to their firearm ownership; some believed these identities were incompatible, so were also not open to intervention. Group 3 owned firearms for protection and believed church, as a community hub, was an excellent location for firearm safety interventions.

CONCLUSIONS

The clustering of participants into groups varying in openness to church-based firearm safety interventions suggests it is feasible to identify Protestant Christian firearm owners open to intervention. This study presents a first step in coupling firearm owner characteristics with community-based, tailored interventions with promise for efficacy.

Long-term functional outcomes after total wrist arthrodesis

Current literature surrounding functional outcomes after total wrist arthrodesis is limited by short follow-up or limited use of validated patient reported outcome measures (PROMs). The primary aim of this study was to describe long-term functional outcomes following wrist arthrodesis. Secondary aims were to describe the incidence of complications and patient satisfaction. This was a retrospective single-center study. Patients with a minimum of 10-year follow-up completed a questionnaire including the Patient-Rated Wrist Evaluation (PRWE), the Quick version of the Disabilities of the Arm, Shoulder and Hand (Quick-DASH) score, the EQ-5D-5L score, and a question assessing satisfaction. Presence of a complication was also assessed. During the study period 66 patients underwent total arthrodesis. At a median follow-up of 15 years, complete patient reported outcomes were available for 34 patients. Thirty-two patients were lost to follow-up. Mean age at surgery was 49 and 16 patients were female. Mean PRWE and Quick-DASH scores were 44.8 (SD 27.7; range 0-96) and 41.9 (SD 23.6; range 2.3-97.7) respectively. Twenty-eight patients were satisfied. Nine patients reported complications. There were six cases of hardware removal and two cases of prominent metalwork. One patient underwent revision surgery for non-union. Presence of a complication did not affect the Quick-DASH or PRWE scores. Median EQ-5D-5L score was 0.7. This long-term follow-up suggests high levels of patient satisfaction and health related quality of life, despite significant functional disability. The complication rates are not insignificant, although the presence of a complication did not affect functional outcomes.

Synthesis and In Vitro Efficacy of Tetracyclic Benzothiazepines against Blood-Stage Plasmodium falciparum and Liver-Stage P. berghei

Objective:

A series of novel, substituted tetracyclic benzothiazepines were designed and prepared in an effort to optimize potency of this chemical class against drug-resistant strains of the malaria parasite.

Method:

Tetracyclic benzothiazepines bearing structural modification at seven distinct positions within the structure were synthesized, in Knoevenagel condensation reactions followed by sequential intermolecular thio-Michael and then intramolecular imine formation reactions. Following purification and chemical characterization, the novel compounds were tested for in vitro efficacy against blood-stage P. falciparum and liver-stage P. berghei, and also for in vivo efficacy against P. berghei.

Results:

Benzothiazepines bearing structural modification at the sulfur atom and at the three carbocycles within the molecule were successfully synthesized. The majority of analogs inhibited blood-stage P. falciparum with submicromolar IC50 values. The potency of an 8-methoxy-substituted analog 12 exceeded that of chloroquine in all three P. falciparum strains tested. The parent benzothiazepine 1 possessed liver-stage activity, inhibiting P. berghei sporozoites infecting HepG2 cells with an IC50 of 106.4 nM and an IC90 of 408.9 nM, but failed to enhance the longevity of P. berghei infected mice compared to the controls. Compounds displayed modest toxicity toward HepG2 cells, and were tolerated by mice at the highest dose tested, 640 mg/kg/dose once daily for three days.

Conclusion:

The tetracyclic benzothiazepine described, which inhibits P. berghei infected hepatic cells with an IC50 of 106.4 nM, would appear to warrant further investigation. Optimization of ADME properties may be required, since the most active analogs are probably excessively lipophilic.

Spindle reorientation in response to mechanical stress is an emergent property of the spindle positioning mechanisms

Proper orientation of the mitotic spindle plays a crucial role in embryos, during tissue development, and in adults, where it functions to dissipate mechanical stress to maintain tissue integrity and homeostasis. While mitotic spindles have been shown to reorient in response to external mechanical stresses, the subcellular cues that mediate spindle reorientation remain unclear. Here, we used a combination of optogenetics and computational modeling to investigate how mitotic spindles respond to inhomogeneous tension within the actomyosin cortex. Strikingly, we found that the optogenetic activation of RhoA only influences spindle orientation when it is induced at both poles of the cell. Under these conditions, the sudden local increase in cortical tension induced by RhoA activation reduces pulling forces exerted by cortical regulators on astral microtubules. This leads to a perturbation of the balance of torques exerted on the spindle, which causes it to rotate. Thus, spindle rotation in response to mechanical stress is an emergent phenomenon arising from the interaction between the spindle positioning machinery and the cell cortex.

ECM degradation in the Drosophila abdominal epidermis initiates tissue growth that ceases with rapid cell-cycle exit

During development, multicellular organisms undergo stereotypical patterns of tissue growth in space and time. How developmental growth is orchestrated remains unclear, largely due to the difficulty of observing and quantitating this process in a living organism. Drosophila histoblast nests are small clusters of progenitor epithelial cells that undergo extensive growth to give rise to the adult abdominal epidermis and are amenable to live imaging. Our quantitative analysis of histoblast proliferation and tissue mechanics reveals that tissue growth is driven by cell divisions initiated through basal extracellular matrix degradation by matrix metalloproteases secreted by the neighboring larval epidermal cells. Laser ablations and computational simulations show that tissue mechanical tension does not decrease as the histoblasts fill the abdominal epidermal surface. During tissue growth, the histoblasts display oscillatory cell division rates until growth termination occurs through the rapid emergence of G0/G1 arrested cells, rather than a gradual increase in cell-cycle time as observed in other systems such as the Drosophila wing and mouse postnatal epidermis. Different developing tissues can therefore achieve their final size using distinct growth termination strategies. Thus, adult abdominal epidermal development is characterized by changes in the tissue microenvironment and a rapid exit from the cell cycle.

Three-dimensional geometry controls division symmetry in stem cell colonies

Proper control of division orientation and symmetry, largely determined by spindle positioning, is essential to development and homeostasis. Spindle positioning has been extensively studied in cells dividing in two-dimensional (2D) environments and in epithelial tissues, where proteins such as NuMA (also known as NUMA1) orient division along the interphase long axis of the cell. However, little is known about how cells control spindle positioning in three-dimensional (3D) environments, such as early mammalian embryos and a variety of adult tissues. Here, we use mouse embryonic stem cells (ESCs), which grow in 3D colonies, as a model to investigate division in 3D. We observe that, at the periphery of 3D colonies, ESCs display high spindle mobility and divide asymmetrically. Our data suggest that enhanced spindle movements are due to unequal distribution of the cell-cell junction protein E-cadherin between future daughter cells. Interestingly, when cells progress towards differentiation, division becomes more symmetric, with more elongated shapes in metaphase and enhanced cortical NuMA recruitment in anaphase. Altogether, this study suggests that in 3D contexts, the geometry of the cell and its contacts with neighbors control division orientation and symmetry. This article has an associated First Person interview with the first author of the paper.

Medical equipment trends during the UK military exercise SAIF SAREEA 3 in Oman

Introduction

Ex SAIF SAREEA 3 was a joint British-Omani military exercise involving approximately 5500 British personnel deployed to Oman over a 6-month period. Role 1 medical care was provided by medical treatment facilities (MTFs) deployed with medical equipment as per the UK 300 medical module.

Method

Retrospective analysis was undertaken of prospectively collected equipment usage data from two Role 1 MTFs in Duqm (MTF 1) and Muaskar Al Murtafa (MTF 2) camps over a period of 6–8 weeks. Data were analysed alongside routinely collected epidemiological data (EPINATO) during the deployment. Equipment used in addition to the module was also recorded.

Results

MTF 1 used 50 out of the 179 different items from the module over the 8-week period. MTF 2 used 45 out of the 179 different items from their module over the 6-week period. The most commonly used items across the sites were non-sterile examination gloves, plastic aprons, tympanic thermometer probe covers, disinfectant wipes and self-adhesive plasters. Extramodular items (blunt fill needle, water pump sprayer, Jelonet gauze and stool specimen pot) accounted for 5% of all equipment used in MTF 1.

Conclusion

The study showed that the 300 module accommodates 95% of Role 1 patients’ needs but highlights the requirement for dedicated equipment for the treatment of heat casualties if deemed likely and blunt fill/filter needles for the administration of parenteral medication. Commanders must perform a thorough medical estimate and risk assessment prior to deployment to ensure that the 300 medical module is likely to provide the necessary equipment and supplement the module if required.

SPIN90 associates with mDia1 and the Arp2/3 complex to regulate cortical actin organization

Cell shape is controlled by the submembranous cortex, an actomyosin network mainly generated by two actin nucleators: the Arp2/3 complex and the formin mDia1. Changes in relative nucleator activity may alter cortical organization, mechanics and cell shape. Here we investigate how nucleation-promoting factors mediate interactions between nucleators. In vitro, the nucleation-promoting factor SPIN90 promotes formation of unbranched filaments by Arp2/3, a process thought to provide the initial filament for generation of dendritic networks. Paradoxically, in cells, SPIN90 appears to favour a formin-dominated cortex. Our in vitro experiments reveal that this feature stems mainly from two mechanisms: efficient recruitment of mDia1 to SPIN90-Arp2/3 nucleated filaments and formation of a ternary SPIN90-Arp2/3-mDia1 complex that greatly enhances filament nucleation. Both mechanisms yield rapidly elongating filaments with mDia1 at their barbed ends and SPIN90-Arp2/3 at their pointed ends. Thus, in networks, SPIN90 lowers branching densities and increases the proportion of long filaments elongated by mDia1.

Managing mental health on a prolonged deployment: UK military exercise SAIF SAREEA 3

INTRODUCTION

This paper presents the burden of mental health cases throughout UK military exercise SAIF SAREEA 3 (SS3), a low-tempo armoured brigade exercise in Oman from June to November 2018, and aims to discuss ways that mental health may be better managed on future large exercises.

METHODS

A retrospective review of all attendances at army medical facilities and relevant computerised medical records was undertaken.

RESULTS

14 mental health cases were identified, which required 51 follow-up presentations throughout the duration of SS3. This represented 1.2% of all first patient presentations, and 6.3% of all follow-up work. 64% had diagnoses which predated deployment and could all be classified within 10th revision of International Statistical Classification of Diseases and Related Health Problems as either F30-F39 mood (affective) disorders, or F40-F48 neurotic, stress-related and somatoform disorders; all new diagnoses made while deployed were adjustment disorders. The medical officer spent an average of 147 min total clinical care time per patient. Six patients were aeromedically evacuated (AE), which represented 26% of all AE cases from SS3.

CONCLUSIONS

Presentations were low, but time consuming and with poor disposal outcomes. Most conditions predated the exercise, and could have been predicted to worsen through the deployment. Given the disproportionate burden that mental health cases afforded during SS3, future brigade-sized deployments should include deployed mental health professionals in order to offer evidence-based therapy which should lead to improved disposal outcomes and a reduced AE burden.

Smoking habits of UK military personnel on deployment: Exercise SAIF SAREEA 3

INTRODUCTION

Changes of environment brought about by deployments are often attributed to an increase in smoking of service personnel. Electronic cigarettes are recognised as being a viable aid to quitting smoking but are currently banned from sale in Oman and were therefore banned during exercise SAIF SAREEA 3 (SS3). This paper sought to establish whether smoking increased on this exercise and for what reasons. Also, if deployed smoking cessation services are likely to be used, if available.

METHODS

Questionnaires were distributed to deployed troops at various locations in theatre for data collection.

RESULTS

Smoking prevalence increased by 5.2% (29) in the deployed population by the end of the exercise. The largest increase was seen in those smoking 20 cigarettes a day or more, rising by 269.8% (73) with a mean increase of 9 cigarettes per day. During the exercise the number of personnel using electronic cigarettes decreased and individuals' rate of electronic cigarette use also decreased. Those who smoked less during the exercise did mainly through choice (56.8%). 50% (280) of all individuals who increased smoking habits during the exercise did so out of boredom.

CONCLUSIONS

During exercise SS3 the number of individuals who smoked and the quantity they smoked increased. The ban on electronic cigarettes in Oman and while on exercise potentially had an effect on the increased smoking habits. There is an argument to include smoking cessation material in medical modules to prevent ex-smokers from restarting, continue to aid those quitting and potentially lessen severity of increasing smoking habits while deployed.

Command application of UK military climatic guidance on Exercise SAIF SAREEA 3

Health and risk management of personnel in hot climates remains a Commander's responsibility, with Joint Service Publication 539 Heat Illness and Cold Injury: Prevention and Management (JSP 539) being the guiding document for the UK military. This policy can be challenging to interpret occasionally, needing medical professionals to provide ongoing advice to commanders. This is to achieve a shared understanding of scientific concepts and risks to allow a more informed decision-making by commanders. This then leads to the appropriate mitigation of risks to as low as reasonably practical. Exercise SAIF SAREEA 3 saw commanders and medical cooperation at all levels with a practical and pragmatic application of the principles articulated in joint policy. The elements which saw enhanced cooperation included pathophysiology, work rates and work:rest ratios, rest and sleep periods, uniform, acclimatisation, and hydration and electrolyte balance. This approach was exhibited throughout the planning, deployment and execution of Exercise SAIF SAREEA 3, which saw extremely low levels of heat injury throughout the exercise when compared with SAIF SAREEA 2 and related exercises. This personal view aims to describe the command and medical interaction on SAIF SAREEA 3 which the authors feel contributed to those successes against climatic effects.

Epidemiology of UK Military Exercise SAIF SAREEA 3: future planning for hot climates

Introduction

Epidemiological data captured from military exercises and operations can highlight treatment requirements specific to operating in certain environmental conditions. Such data is invaluable to enable accurate planning for future exercises. Epidemiological data were collected during Exercise SAIF SAREEA 3 (SS3) to provide an insight into medical provision requirements for low-tempo military operations in hot, desert climates.

Method

Epidemiological data was collected from all consultations conducted during the exercise within the LAND Medical Reception Station, 24 August–14 November 2018, using Epi-NATO surveillance systems.

Results

Of the 1414 total consultations recorded, 759 were first presentations and 665 were follow-up consultations, with 35 referrals made to hospitals. 1348 days of limited duties were given and 258 working days were lost. The most common coding reported for consultations were ‘non-battle non-sport related injuries’, ‘sport related injuries’ and ‘dermatological'.

Discussion

The data highlight the most common cause of injuries and the role of assets such as dental, sexual and mental health services for future deployments. A number of explanations are considered in relation to the patterns identified and the effect on future planning for working in hot climates. Furthermore, Exercise SS3 had reduced numbers of personnel requiring deployed Role 2 or host nation hospital services, which again raises further considerations for future deployments.

Structuring a UK military role 1 medical treatment facility for a sustained mobile exercise in a hot desert environment: UK military exercise SAIF SAREEA 3

Exercise SAIF SAREEA 3 (SS3) is a triservice combined joint training military Exercise between the UK and the Omani Armed forces. SS3 represented a rare opportunity to exercise a complete role 1 medical reception station (MRS) in a tented platform for a prolonged period providing 'real life support', as opposed to an exercise without casualties. This article is a discursive paper making recommendations for amendments to the established structure for the MRS within static high-temperature deployments. Considering the facility blueprint, recognising and implementing improvements to patient flow and increasing infection prevention control measures resulted in limiting the spread of disease outbreak. During the deployment there were considerable challenges delivering care in extreme heat above 50°C these included the use of environmental control units, white liners and refrigerator units which allowed care to be delivered throughout the day, and for the appropriate care of both casualties and medication. Finally, the article covers improved patient service with a paper-based triage system supporting innovative ideas to deliver care.

Effects of heat: UK exercise Saif Sareea 3 and interpreting military climatic guidance

Introduction

Over recent years much research, both civilian and military, has occurred in the field of heat illness. This has helped force health protection and medical management of service personnel operating in hot climates. Exercise Saif Sareea 3 in Oman saw a collection of presentations to the deployed UK medical treatment facilities due to the effects of heat.

Method

This paper aims to describe the case series of 24 casualties that presented to the deployed primary care facilities and 17 that were admitted to the deployed secondary care facility due to the effects of heat.

Results

Only 10 casualties fulfilled the in-theatre diagnostic criteria for heat illness, of which two were of moderate severity and required aeromedical evacuation to the UK.

Conclusions

Commanders appeared extremely well read on Joint Service Publication 539 (JSP539; May 2017) Heat Illness and Cold Injury: Prevention and Management, following the Brecon enquiry, and were proactive in managing their force in preventative measures. This likely contributed towards the low numbers of patients with heat illness seen on the exercise. JSP539 did, however, appear to have some limitations when trying to apply it to all patients seen within the operational patient care pathway, and some areas for development are discussed.

A UK Military nurse practitioner on Exercise SAIF SAREEA 3: the first Overseas deployment

As the Queen Alexandra’s Royal Army Nursing Corps celebrates its 70th Anniversary, army nursing continues to advance patient care delivery to new levels. Advanced level nursing practice has moved from the relatively ‘calm’ confines of the NHS to the austere desert of Oman. This article will provide a personal account of the first deployment of a military nurse practitioner since it was formally introduced in 2012 to frontline medicine, leading an armoured prehospital treatment team.

Prescribing in the prehospital environment: a review of the pharmaceutical Module 501 on UK Military Exercise SAIF SAREEA 3. Can such analysis assist with the scaling of healthcare assets?

INTRODUCTION

Module 501 provides core medications which are fundamental to the capability of a prehospital treatment team (PHTT). The quantities of each medication in the module inventory undergo regular review, but these do not correspond to a population at risk (PAR) figure or deployment length for which they intend to be used. This article proposes how the quantities of Module 501 drugs can be scaled for a given deployment, in this example using statistics taken from static PHTTs on Exercise Saif Sareea 3 (SS3).

METHODS

The statistics were gathered using a custom-built search of electronic records from the Deployed Defence Medical Information Capability Programme in addition to written record-keeping, which were aligned to the weekly PAR at each PHTT location throughout their full operational capability periods. A quotient was then derived for each module item using a formula.

RESULTS

Among the 10 most commonly prescribed drugs were four analgesics and three antimicrobials. 42 of the 110 studied drugs were not prescribed during SS3.

DISCUSSION

The data from SS3 reflect the typical scope of disease encountered in the deployed land setting. Employing these data, the use of a formula to estimate the drug quantities needed to sustain a Strike Armoured Infantry Brigade over a 28-day period is demonstrated.

RECOMMENDATIONS

Further study of Module 501 across varied deployment environments would be valuable in evolving this approach to medicinal scaling if proven effective for the warm desert climate. It could then be applied to other modules to further inform future Strike medical planning.

LIMITATIONS

Several considerations when drawing deductions from the data are mentioned, including the inaccuracy of predictor variables taken from the EpiNATO-2 reports.

CONCLUSION

The proposed formula provides an evidence-based framework for scaling drug quantities for a deployment planning. This may improve patient safety and confer logistical, storage and fiscal benefits.

Role of the pre-hospital treatment team on the UK military exercise SAIF SAREEA 3

The prehospital treatment team (PHTT) involves a small team working under the clinical supervision of a clinical lead. The clinical lead can be a general duties medical officer (Post Foundation Years Doctor), military nurse practitioner or more senior clinician. The team is mounted in vehicles appropriate to the environment they expect to operate in. A PHTT is closely located to the front line reducing transportation timelines from the point of wounding to more definitive care. The PHTT can provide medical support on the move or when time is available; a more permanent fully erected treatment facility can be established. Either configuration can provide both trauma and primary care. The size of the team allows for multiple trauma subteams enabling care to casualties that arrive simultaneously. The PHTT can move independently which could leave the team vulnerable as there is no integral force protection within the current structure. In such a small team, the right balance of medical and soldiering skills among team members is essential to success. Exercise SAIF SAREEA 3 represented a large-scale battlegroup exercise to the Middle East in the austere desert of Oman. This provided an ideal environment for employing the PHTT concept is a large deployed force undertaking dynamic activity.

Conservative surgery for ovarian torsion in young women: perioperative complications and national trends

OBJECTIVE

To analyse populational trends and perioperative complications following conservative surgery versus oophorectomy in women <50 years of age with ovarian torsion.

DESIGN

Population-based retrospective observational study.

SETTING

Nationwide Inpatient Sample in the USA (2001-2015).

POPULATION

In all, 89 177 ovarian torsions including 20 597 (23.1%) conservative surgeries and 68 580 (76.9%) oophorectomies.

METHODS

(1) Trend analysis to assess utilisation of conservative surgery over time, (2) multivariable binary logistic regression to identify independent factors associated with conservative surgery and (3) inverse probability of treatment weighting with a generalised estimating equation to analyze perioperative complications.

MAIN OUTCOME MEASURES

Trends, characteristics and complications related to conservative surgery.

RESULTS

Performance of conservative surgery increased from 18.9 to 25.1% between 2001 and 2015 (32.8% relative increase, P = 0.001) but decreased steadily after age 15, and sharply declined after age 35 (P < 0.001). On multivariable analysis, younger age exhibited the largest effect size for conservative surgery among the independent factors (adjusted odds ratios 3.39-7.96, P < 0.001). In the weighted model, conservative surgery was associated with an approximately 30% decreased risk of perioperative complications overall (10.0% versus 13.6%, odds ratio 0.73, 95% confidence interval 0.62-0.85, P < 0.001) and was not associated with venous thromboembolism (0.2 versus 0.3%, P = 0.457) or sepsis (0.4 versus 0.3%, P = 0.638).

CONCLUSION

There has been an increasing utilisation of conservative surgery for ovarian torsion in the USA in recent years. Our study suggests that conservative surgery for ovarian torsion may not be associated with increased perioperative complications.

TWEETABLE ABSTRACT

Conservative surgery for ovarian torsion may not be associated with increased perioperative complications.

Actin cortex architecture regulates cell surface tension

Animal cell shape is largely determined by the cortex, a thin actin network underlying the plasma membrane in which myosin-driven stresses generate contractile tension. Tension gradients result in local contractions and drive cell deformations. Previous cortical tension regulation studies have focused on myosin motors. Here, we show that cortical actin network architecture is equally important. First, we observe that actin cortex thickness and tension are inversely correlated during cell-cycle progression. We then show that the actin filament length regulators CFL1, CAPZB and DIAPH1 regulate mitotic cortex thickness and find that both increasing and decreasing thickness decreases tension in mitosis. This suggests that the mitotic cortex is poised close to a tension maximum. Finally, using a computational model, we identify a physical mechanism by which maximum tension is achieved at intermediate actin filament lengths. Our results indicate that actin network architecture, alongside myosin activity, is key to cell surface tension regulation.

An active contour ImageJ plugin to monitor daughter cell size in 3D during cytokinesis

Controlling relative daughter cell size is key during cytokinesis. Uncontrolled size asymmetries can lead to aneuploidy and division failure. At the same time, precisely regulated size asymmetries are of crucial importance in many divisions during embryonic development. Therefore, being able to monitor daughter cell size is important in cytokinesis studies. However, freely available tools allowing to effectively measure the size of daughter cells in three dimensions during cytokinesis are missing. Here, we describe an open-access plugin for ImageJ or Fiji based on an active contour surface representation of the cells. Our method provides a user-friendly and accurate way to monitor the size of the two daughter cells throughout cytokinesis.

Just a routine operation: a critical discussion

This article has summarised a critical discussion of the human factors that contributed to the death of a patient from a failure to respond appropriately to a 'can't intubate, can't ventilate' scenario. The contributory factors included the clinical team's inability to communicate, prioritise tasks and demonstrate effective leadership and assertive followership. The film Just a routine operation has now been in circulation for several years. When a system is designed and introduced with the intention of making a change to clinical practice, it can quickly become just another component of an organisation's architecture and complacency around its use can develop. This article has been written specifically for perioperative practitioners to renew the debate around the human factors that contribute to patient harm. By critically discussing Just a routine operation and attempting to review why the incident occurred, this article has attempted to emphasise that some of the conditions and behaviours that contributed to the death of Elaine Bromiley may be latent within our organisations and teams, and may continue to contribute to failures that affect patient safety.

Bubble-detector measurements of neutron radiation in the international space station: ISS-34 to ISS-37

Bubble detectors have been used to characterise the neutron dose and energy spectrum in several modules of the International Space Station (ISS) as part of an ongoing radiation survey. A series of experiments was performed during the ISS-34, ISS-35, ISS-36 and ISS-37 missions between December 2012 and October 2013. The Radi-N2 experiment, a repeat of the 2009 Radi-N investigation, included measurements in four modules of the US orbital segment: Columbus, the Japanese experiment module, the US laboratory and Node 2. The Radi-N2 dose and spectral measurements are not significantly different from the Radi-N results collected in the same ISS locations, despite the large difference in solar activity between 2009 and 2013. Parallel experiments using a second set of detectors in the Russian segment of the ISS included the first characterisation of the neutron spectrum inside the tissue-equivalent Matroshka-R phantom. These data suggest that the dose inside the phantom is ∼70% of the dose at its surface, while the spectrum inside the phantom contains a larger fraction of high-energy neutrons than the spectrum outside the phantom. The phantom results are supported by Monte Carlo simulations that provide good agreement with the empirical data.

Response of the bubble detector to neutrons of various energies

A series of Monte-Carlo simulations has been performed in order to investigate the response of the bubble detector to monoenergetic neutrons of various energies. The work was driven by the need to better understand the energy dependence of the detector for applications in space, where the neutron spectrum has a significant component with energy of >20 MeV. The response to neutrons in the range of a few keV to 500 MeV has been calculated, and good agreement between the simulations and experimental data is demonstrated over the entire energy range.

Bubble-detector measurements in the Russian segment of the International Space Station during 2009-12

Measurements using bubble detectors have been performed in order to characterise the neutron dose and energy spectrum in the Russian segment of the International Space Station (ISS). Experiments using bubble dosemeters and a bubble-detector spectrometer, a set of six detectors with different energy thresholds that is used to determine the neutron spectrum, were performed during the ISS-22 (2009) to ISS-33 (2012) missions. The spectrometric measurements are in good agreement with earlier data, exhibiting expected features of the neutron energy spectrum in space. Experiments using a hydrogenous radiation shield show that the neutron dose can be reduced by shielding, with a reduction similar to that determined in earlier measurements using bubble detectors. The bubble-detector data are compared with measurements performed on the ISS using other instruments and are correlated with potential influencing factors such as the ISS altitude and the solar activity. Surprisingly, these influences do not seem to have a strong effect on the neutron dose or energy spectrum inside the ISS.

New single-molecule speckle microscopy reveals modification of the retrograde actin flow by focal adhesions at nanometer scales

This paper introduces a new, easy-to-use method of fluorescence single-molecule speckle microscopy for actin with nanometer-scale accuracy. This new method reveals that actin flows in front of mature focal adhesions (FAs) are fast and biased toward FAs, suggesting that mature FAs are actively engaged in pulling and remodeling the local actin network.

Speckle microscopy directly visualizes the retrograde actin flow, which is believed to promote cell-edge protrusion when linked to focal adhesions (FAs). However, it has been argued that, due to rapid actin turnover, the use of green fluorescent protein–actin, the lack of appropriate analysis algorithms, and technical difficulties, speckle microscopy does not necessarily report the flow velocities of entire actin populations. In this study, we developed a new, user-friendly single-molecule speckle (SiMS) microscopy using DyLight dye-labeled actin. Our new SiMS method enables in vivo nanometer-scale displacement analysis with a low localization error of ±8–8.5 nm, allowing accurate flow-velocity measurement for actin speckles with lifetime <5 s. In lamellipodia, both short- and long-lived F-actin molecules flow with the same speed, indicating they are part of a single actin network. These results do not support coexistence of F-actin populations with different flow speeds, which is referred to as the lamella hypothesis. Mature FAs, but not nascent adhesions, locally obstruct the retrograde flow. Interestingly, the actin flow in front of mature FAs is fast and biased toward FAs, suggesting that mature FAs attract the flow in front and actively remodel the local actin network.

Pertuzumab for the treatment of patients with previously untreated HER2-positive metastatic breast cancer

Pertuzumab is a humanized monoclonal antibody directed at the dimerization domain of the receptor tyrosine-protein kinase erbB-2 (HER2) receptor. It possesses a unique and complimentary mechanism of action compared to trastuzumab, which has historically been the cornerstone of therapy for HER2-amplified breast cancer. Clinical trials demonstrate improved outcomes, with minimal increases in toxicity with the addition of pertuzumab to trastuzumab in patients with HER2-positive metastatic breast cancer, indicating the advantage of dual HER2 receptor blockade. Pertuzumab is approved as first-line therapy in combination with trastuzumab and docetaxel for HER2-positive metastatic breast cancer, with future opportunities to investigate its efficacy in other stages of breast cancer, as well as in the treatment of other malignancies.

Measurements of the neutron dose and energy spectrum on the International Space Station during expeditions ISS-16 to ISS-21

As part of the international Matroshka-R and Radi-N experiments, bubble detectors have been used on board the ISS in order to characterise the neutron dose and the energy spectrum of neutrons. Experiments using bubble dosemeters inside a tissue-equivalent phantom were performed during the ISS-16, ISS-18 and ISS-19 expeditions. During the ISS-20 and ISS-21 missions, the bubble dosemeters were supplemented by a bubble-detector spectrometer, a set of six detectors that was used to determine the neutron energy spectrum at various locations inside the ISS. The temperature-compensated spectrometer set used is the first to be developed specifically for space applications and its development is described in this paper. Results of the dose measurements indicate that the dose received at two different depths inside the phantom is not significantly different, suggesting that bubble detectors worn by a person provide an accurate reading of the dose received inside the body. The energy spectra measured using the spectrometer are in good agreement with previous measurements and do not show a strong dependence on the precise location inside the station. To aid the understanding of the bubble-detector response to charged particles in the space environment, calculations have been performed using a Monte-Carlo code, together with data collected on the ISS. These calculations indicate that charged particles contribute <2% to the bubble count on the ISS, and can therefore be considered as negligible for bubble-detector measurements in space.

Review of bubble detector response characteristics and results from space

A passive neutron-bubble dosemeter (BD), developed by Bubble Technology Industries, has been used for space applications. Both the bubble detector-personal neutron dosemeter and bubble detector spectrometer have been studied at ground-based facilities in order to characterise their response due to neutrons, heavy ion particles and protons. This technology was first used during the Canadian-Russian collaboration aboard the Russian satellite BION-9, and subsequently on other space missions, including later BION satellites, the space transportation system, Russian MIR space station and International Space Station. This paper provides an overview of the experiments that have been performed for both ground-based and space studies in an effort to characterise the response of these detectors to various particle types in low earth orbit and presents results from the various space investigations.

Abstract 4527: The HER3-EREG axis and its role in colorectal cancer aggression

Yearly, 50,000 Americans die of colorectal cancer metastases to liver and lung. EGFR-targeted agents improve survival in a subset of metastatic colorectal cancer (mCRC) cases, and overexpression of the HER-family ligands amphiregulin (AREG) and epiregulin (EREG) correlates with EGFR-targeted agent susceptibility. Here we present evidence of association between EREG overexpression and disease aggression by showing that knockdown of EREG or HER3 impede anchorage independent growth in the HCT 116 CRC cell line. We also find that a HER3-EREG axis gene signature groups mCRC tumors into prognostically distinct groups. Snap-frozen CRC hepatic metastases (65) with patient matched normal liver, as well as 71 primary CRC tumors with patient matched normal colonic mucosa were analyzed via qRT-PCR for receptors (HER1-4) and ligands (AREG, and EREG). Among the mCRC cases HER2, HER3, AREG, and EREG were expressed at higher levels than unmatched normal mucosa (p&lt;0.005). HER2, AREG, and EREG were also overexpressed in mCRC compared to unmatched primary CRC tissue (p&lt;0.005). Expression of AREG and EREG were highly correlated (Rs=0.90), and higher EREG mRNA expression was associated with markedly decreased post-hepatectomy overall survival (OS) (p=0.018). In a panel of 9 CRC cell lines HCT 116 had the highest EREG expression. Using the pLKO.1 viral vector, shRNAs targeting EREG, and HER3 were introduced to HCT 116 cells. Empty vector was used as a control. mRNA levels for HER3 and EREG were knocked down by 87% and 73% respectively and protein downregulation was confirmed by western blot. Knockdown and control cells were grown in 0.35% soft agar at a density of 5000 cells per well in 6 well plates. Knockdowns impeded anchorage independent growth with a mean colony count (&gt;50 um diameter) of 170 for HER3, and 285 for EREG as compared to 530 for the empty vector (p&lt;0.005). RNA from 3 distinct sets of HER3, EREG, and empty vector infections was assayed on Agilent Human GE 4x44K v2 microarrays. Unsupervised Principle Component Analysis (PCA) suggested broad concordance in the impact of EREG or HER3 knockdown upon the expression profile. Statistical Analysis of Microarrays (SAM) comparing HER3, and EREG knockdowns to empty vector control revealed 205, and 432 differentially expressed genes with at least a 1.5 fold-change and a false discovery rate of 0%. When HER3 and EREG differential gene lists were compared, 95 overlapping genes with 100% directional agreement were observed. For 51 mCRC cases RNA was available for microarray analysis. A predictor of HER3-EREG activity was constructed from 250 genes that discriminate HER3/EREG knockdown and empty vector control cells and are generally variable in tumors. The predictor was used to assign a HER3-EREG activity score to each mCRC case. This score is significantly associated with OS (p=0.005) with the top 50% of patients by HER3-EREG score demonstrating 5 year OS of 23% as compared to 49% for cases in the lower half of HER3-EREG activity.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4527. doi:1538-7445.AM2012-4527

Interactive, computer-assisted tracking of speckle trajectories in fluorescence microscopy: application to actin polymerization and membrane fusion

Analysis of particle trajectories in images obtained by fluorescence microscopy reveals biophysical properties such as diffusion coefficient or rates of association and dissociation. Particle tracking and lifetime measurement is often limited by noise, large mobilities, image inhomogeneities, and path crossings. We present Speckle TrackerJ, a tool that addresses some of these challenges using computer-assisted techniques for finding positions and tracking particles in different situations. A dynamic user interface assists in the creation, editing, and refining of particle tracks. The following are results from application of this program: 1), Tracking single molecule diffusion in simulated images. The shape of the diffusing marker on the image changes from speckle to cloud, depending on the relationship of the diffusion coefficient to the camera exposure time. We use these images to illustrate the range of diffusion coefficients that can be measured. 2), We used the program to measure the diffusion coefficient of capping proteins in the lamellipodium. We found values ∼0.5 μm(2)/s, suggesting capping protein association with protein complexes or the membrane. 3), We demonstrate efficient measuring of appearance and disappearance of EGFP-actin speckles within the lamellipodium of motile cells that indicate actin monomer incorporation into the actin filament network. 4), We marked appearance and disappearance events of fluorescently labeled vesicles to supported lipid bilayers and tracked single lipids from the fused vesicle on the bilayer. This is the first time, to our knowledge, that vesicle fusion has been detected with single molecule sensitivity and the program allowed us to perform a quantitative analysis. 5), By discriminating between undocking and fusion events, dwell times for vesicle fusion after vesicle docking to membranes can be measured.

Segmentation and tracking of cytoskeletal filaments using open active contours

We use open active contours to quantify cytoskeletal structures imaged by fluorescence microscopy in two and three dimensions. We developed an interactive software tool for segmentation, tracking, and visualization of individual fibers. Open active contours are parametric curves that deform to minimize the sum of an external energy derived from the image and an internal bending and stretching energy. The external energy generates (i) forces that attract the contour toward the central bright line of a filament in the image, and (ii) forces that stretch the active contour toward the ends of bright ridges. Images of simulated semiflexible polymers with known bending and torsional rigidity are analyzed to validate the method. We apply our methods to quantify the conformations and dynamics of actin in two examples: actin filaments imaged by TIRF microscopy in vitro, and actin cables in fission yeast imaged by spinning disk confocal microscopy.

Neutron reflectometry of supported hybrid bilayers with inserted peptide

The insertion of a synthetic amphiphilic, α-helical peptide into a supported hybrid bilayer membrane (HBM) was studied by neutron reflectometry to elucidate the resulting nanostructure. The HBM consisted of a self-assembled monolayer of perdeuterated octadecanethiol on gold and an overlying leaflet of acyl-deuterated phosphatidylcholine (d-DMPC). Using contrast variation, several reflectivity spectra were recorded for each step of film fabrication, and simultaneously modeled. This analysis indicated that peptide insertion into the DMPC lipid leaflet is the likeliest mode of incorporation.

Asphaltene adsorption onto self-assembled monolayers of mixed aromatic and aliphatic trichlorosilanes

The adsorption of asphaltenes onto flat solid surfaces modified with mixed self-assembled monolayers (SAMs) of aliphatic and aromatic trichlorosilanes with varying wettabilities, aromaticities, and thicknesses is tested. The mixed SAMs are characterized by means of contact angle to assess hydrophobicity and molecular and chemical uniformity, spectroscopic ellipsometry to measure the thickness of the films, and near edge X-ray absorption fine structure (NEXAFS) spectroscopy to assess chemical and molecular composition. The molecular characteristics of the adsorbed asphaltene layer and the extent of asphaltene adsorption are determined using NEXAFS and spectroscopic ellipsometry, respectively. The SAMs are formed by depositing phenyl-, phenethyl-, butyl-, and octadecyl- trichlorosilanes from toluene solutions onto silica-coated substrates; the chemical composition and the wettability of the SAM surface is tuned systematically by varying the trichlorosilane composition in the deposition solutions. The adsorption of asphaltenes on the substrates does not correlate strongly with the SAM chemical composition. Instead, the extent of asphaltene adsorption decreases with increasing SAM thickness. This observation suggests that the leading interaction governing the adsorption of asphaltenes is their interaction with the polar silica substrate and that the chemical composition of the SAM is of secondary importance.

AUTOMATED ACTIN FILAMENT SEGMENTATION, TRACKING AND TIP ELONGATION MEASUREMENTS BASED ON OPEN ACTIVE CONTOUR MODELS

This paper presents an automated method for actin filament segmentation and tracking for measuring tip elongation rates in Total Internal Reflection Fluorescence Microscopy (TIRFM) images. The main contributions of the paper are: (i) we use a novel open active contour model for filament segmentation and tracking, which is fast and robust against noise; (ii) different strategies are proposed to solve the filament intersection problem, which is shown to be the main difficulty in filament tracking; and (iii) this fully automated method avoids the need of human interaction and thus reduces required time for the entire elongation measurement process on an image sequence. Application to experimental results demonstrated the robustness and effectiveness of this method.

Neutron dose study with bubble detectors aboard the International Space Station as part of the Matroshka-R experiment

As part of the Matroshka-R experiments, a spherical phantom and space bubble detectors (SBDs) were used on board the International Space Station to characterise the neutron radiation field. Seven experimental sessions with SBDs were carried out during expeditions ISS-13, ISS-14 and ISS-15. The detectors were positioned at various places throughout the Space Station, in order to determine dose variations with location and on/in the phantom in order to establish the relationship between the neutron dose measured externally to the body and the dose received internally. Experimental data on/in the phantom and at different locations are presented.

Urinary and serum silicon in normal and uraemic individuals

The urinary excretion of silicon (Si) in humans was studied in normal subjects on a low Si diet, a normal diet, and after ingestion of silicate antacid. Measurements of 24-hour urinary excretion of Si showed that urinary Si was derived mainly from dietary intake. The serum concentration of Si was determined in normal individuals and in patients with chronic renal failure. In health, serum Si is maintained within a narrow range, but a significant hypersilicaemia occurs in uraemia. The concentration of Si was measured in the water supply, dialysate and pre-dialysis and post-dialysis serum in patients on regular haemo-dialysis in three areas with low, intermediate and high concentrations of Si in the water supply. Si was removed during dialysis in the region where it was naturally low in the water or where reverse osmosis was used, but it was dialysed into patients in regions with intermediate and high concentrations in the water. Serum Si levels returned to normal after renal transplantation. Preliminary analysis of the geographical variation in the Si content of tap water suggests that uraemic hypersilicaemia may protect haemodialysed patients from the development of aluminium dementia. The kidney would appear from these studies to be the major organ for elimination of absorbed Si.

Study of the packing density and molecular orientation of bimolecular self-assembled monolayers of aromatic and aliphatic organosilanes on silica

Bimolecular self-assembled monolayers (SAMs) of aromatic and aliphatic chlorosilanes were self-assembled onto silica, and their characteristics were established by contact angle measurement, near-edge X-ray absorption fine structure spectroscopy, and Fourier transform infrared spectroscopy. Three aromatic constituents (phenyltrichlorosilane, benzyltrichlorosilane, and phenethyltrichlorosilane) were studied in combination with four aliphatic coadsorbates (butyltrichlorosilane, butyldimethylchlorosilane, octadecyltrichlorosilane, and octadecyldimethylchlorosilane). Our results demonstrate that whereas SAMs made of trichlorinated organosilanes are densely packed, SAMs prepared from monochlorinated species are less dense and poorly ordered. In mixed systems, trichlorinated aromatics and trichlorinated aliphatics formed SAMs with highly tunable compositions; their surfaces were compositionally homogeneous with no large-scale domain separation. The homogeneous nature of the resulting SAM was a consequence of the formation of in-plane siloxane linkages among neighboring molecules. In contrast, when mixing monochlorinated aliphatics with trichlorinated aromatics, molecular segregation occurred. Although the two shortest aromatic species did not display significant changes in orientation upon mixing with aliphatics, the aromatic species with the longest polymethylene spacer, phenethyltrichlorosilane, displayed markedly different orientation behavior in mixtures of short- and long-chain aliphatics.

Precision branching ratio measurement for the superallowed beta+ emitter 62Ga and isospin-symmetry-breaking corrections in A>or=62 nuclei

A high-precision branching ratio measurement for the superallowed beta+ decay of 62Ga was performed at the Isotope Separator and Accelerator radioactive ion beam facility. Nineteen gamma rays emitted following beta+ decay of 62Ga were identified, establishing the dominant superallowed branching ratio to be (99.861+/-0.011)%. Combined with recent half-life and Q-value measurements, this branching ratio yields a superallowed ft value of 3075.6+/-1.4 s for 62Ga decay. These results demonstrate the feasibility of high-precision superallowed branching ratio measurements in the A>or=62 mass region and provide the first stringent tests of the large isospin-symmetry-breaking effects predicted for these decays.

Effects of synthetic amphiphilic alpha-helical peptides on the electrochemical and structural properties of supported hybrid bilayers on gold

Amphiphilic alpha-helices were formed from designed synthetic peptides comprising alanine, phenylalanine, and lysine residues. The insertion of the alpha-helical peptides into hybrid bilayers assembled on gold was studied by a variety of methods to assess the resulting structural characteristics, such as electrical resistance and molecular orientation. Self-assembled monolayers (SAMs) of dodecanethiol (DDT); octadecanethiol (ODT); and 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (DPPTE) were formed on gold substrates with and without incorporated peptide. Supported hybrid bilayers and multilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) were formed on SAMs by the "paint-freeze" method of bilayer formation. Modeling of electrochemical impedance spectroscopy data using equivalent electrochemical circuits revealed that the addition of peptide decreased dramatically the resistive element of the bilayer films while maintaining the value of the capacitive element, indicating successful incorporation of peptide into a well-formed bilayer. Near-edge X-ray absorption fine structure spectroscopy data provided evidence that the molecules in the SAMs and hybrid multilayers were ordered even in the presence of peptide. The peptide insertion into the SAM was confirmed by observing the pi* resonance peak correlating with phenylalanine and a peak in the nitrogen K-edge regime attributable to the peptide bond.

Evidence for nontermination of rotational bands in 74Kr

Three rotational bands in 74Kr were studied up to (in one case one transition short of) the maximum spin I(max) of their respective single-particle configurations. Their lifetimes have been determined using the Doppler-shift attenuation method. The deduced transition quadrupole moments reveal a modest decrease, but far from a complete loss of collectivity at the maximum spin I(max). This feature, together with the results of mean field calculations, indicates that the observed bands do not terminate at I = I(max).

Adaptive Real-Time Closed-Loop Temperature Control for Ultrasound Hyperthermia Using Magnetic Resonance Thermometry

Previous researchers have successfully demonstrated the application of temperature feedback control for thermal treatment of disease using MR thermometry. Using the temperature-dependent proton resonance frequency (PRF) shift, ultrasound heating for hyperthermia to a target organ (such as the prostate) can be tightly controlled. However, using fixed gain controllers, the response of the target to ultrasound heating varies with type, size, location, shape, stage of growth, and proximity to other vulnerable organs. To adjust for clinical variables, feedback self-tuning regulator (STR) and model reference adaptive control (MRAC) methods have been designed and implemented using real-time, online MR thermometry by adjusting the output power to an ultrasound array to quickly reach the hyperthermia target temperatures. The use of fast adaptive controllers in this application is advantageous because adaptive controllers do not require a priori knowledge of the initial tissue properties and blood perfusion and can quickly reach the steady-state target temperature in the presence of dynamic tissue properties (e.g., thermal conductivity, blood perfusion). This research was conducted to rapidly achieve and manage therapeutic temperatures from an ultrasound array using novel MRI-guided adaptive closed-loop controllers both in ex vivo and in vivo experiments. The ex vivo phantom experiments with bovine muscle (n = 5) show that within 6 ± 0.2 minutes, the tissue temperature increased by 8 ± 1.37°C. Using rabbits' (n = 5) thigh muscle, the in vivo experiments demonstrated the target temperature reached 44.5°C ± 1.2°C in 8.0 ± 0.5 minutes. The preliminary in vivo experiment with canine prostate hyperthermia achieved 43 ± 2°C in 6.5 ± 0.5 minutes. These results demonstrate that the adaptive controllers with MR thermometry are able to effectively track the target temperature with dynamic tissue properties.

Regional activation in the rat brain during visceral stimulation detected by c-fos expression and fMRI

AIM

The aim of the study was to determine and compare the areas of brain activated in response to colorectal distention (CRD) using functional magnetic resonance imaging (fMRI) and c-fos protein expression.

METHODS

For fMRI study (3.0 T magnet), anaesthetized rats underwent phasic CRD, synchronized with fMRI acquisition. Stimulation consisted of eight cycles of balloon deflation (90 s) and inflation (30 s), at 40, 60 or 80 mmHg of pressure. For c-fos study two sets of experiments were performed on anaesthetized rats: comparing (A) brain activation in rats with the inserted colorectal balloon (n = 5), to the rats without the balloon (n = 5); and (B) rats with inserted balloon (n = 10), to the rats with inserted and distended balloon (n = 10). The pressure of 80 mmHg was applied for 2 h of 30 s inflation and 90 s deflation, alternating cycles.

RESULTS

Functional MRI revealed significant activation in the amygdala, hypothalamus, thalamus, cerebellum and hippocampus. Significant increase in c-fos expression was observed in amygdala and thalamus in the first set of experiments, and hypothalamus and parabrachial nuclei in the second.

CONCLUSION

The two methods are not interchangeable but appeared to be complementary: fMRI was more sensitive, whereas c-fos had much greater resolution.

Calculations of B1 Distribution, Specific Energy Absorption Rate, and Intrinsic Signal-to-Noise Ratio for a Body-Size Birdcage Coil Loaded with Different Human Subjects at 64 and 128 MHz

A numerical model of a female body is developed to study the effects of different body types with different coil drive methods on radio-frequency magnetic (B₁) field distribution, specific energy absorption rate (SAR), and intrinsic signal-to-noise ratio (ISNR) for a body-size birdcage coil at 64 and 128 MHz. The coil is loaded with either a larger, more muscular male body model (subject 1) or a newly developed female body model (subject 2), and driven with two-port (quadrature), four-port, or many (ideal) sources. Loading the coil with subject 1 results in significantly less homogeneous B₁ field, higher SAR, and lower ISNR than those for subject 2 at both frequencies. This dependence of MR performance and safety measures on body type indicates a need for a variety of numerical models representative of a diverse population for future calculations. The different drive methods result in similar B₁ field patterns, SAR, and ISNR in all cases.

1H magnetic resonance spectroscopy of nanomelic chicken cartilage: effect of aggrecan depletion on cartilage T2

OBJECTIVE

To determine the effect of proteoglycan depletion on cartilage proton magnetic resonance (MR) spectroscopy T2 using nanomelic chicken cartilage, a genetic mutant that completely lacks aggrecan.

DESIGN

Proton MR spectroscopic T2 measurements of normal embryonic and nanomelic femoral epiphyseal cartilage were obtained using a 96-echo pulse sequence with inter-echo delay times increased logarithmically over the TE period of 60 micros to 1.7 s. The relative intensity and distribution of cartilage T2 components were determined by fitting signal decay curves to a multi-exponential function. The number of T2 components in the signal decay curves was determined by the degree of freedom limited r2 of the fit.

RESULTS

For normal fetal chicken cartilage, 97.6 +/- 0.2% (mean +/- 95% confidence interval) of the total signal comprises a long T2 component (179.1 +/- 1.3 ms) with a relatively small short T2 component (0.5 +/- 0.4 ms). The T2 distribution for nanomelic cartilage is more heterogeneous with four components identified: two short T2 components (0.5 +/- 0.02 and 7.3 +/- 0.6 ms), a large intermediate component (56.4 +/- 5.6 ms), and a broadly distributed long component (137.5 +/- 16.6 ms). In nanomelic cartilage there is greater heterogeneity of cartilage T2 indicating greater variation in water proton mobility and exchange of water with the extracellular matrix.

CONCLUSION

Absence of aggrecan in the extracellular cartilage matrix produces greater heterogeneity in cartilage T2, but will not increase T2 as has been previously reported with degenerative change of the collagen matrix.