Design and characterisation of a minibeam collimator utilising Monte Carlo simulation and a clinical linear accelerator

Spatially fractionated radiotherapy is showing promise as a treatment modality. Research has primarily focused on applications in proton therapy, however, there is some evidence that minibeam effects may also be present in photon therapy. This study presents a 3D printed tungsten minibeam collimator intended to produce peak-to-valley dose ratios (PVDR) of between seven and ten with a 1 MeV, bremsstrahlung generated, photon beam. The design of the collimator is motivated by a Monte Carlo study estimating the peak to valley dose ratio for different collimator designs at different energies. This collimator was characterised on a clinical linear accelerator (Elekta VersaHD). It was found that 1 MeV photon sources may generate PVDRs in the region of seven. The performance of the fabricated collimator was measured on a 250 keV superficial treatment unit and an Elekta VersaHD running in unflattened mode with a 6 MV beam. On the superficial unit the measured PVDR was greater than 10. On the Elekta VersaHD units the PVDR was measured to be between approximately 1.5 and 2.0 at 3 cm deep.

Peptide Binder to Glypican-3 as a Theranostic Agent for Hepatocellular Carcinoma

Glypican-3 (GPC3) is a membrane-associated glycoprotein that is significantly upregulated in hepatocellular carcinomas (HCC) with minimal to no expression in normal tissues. The differential expression of GPC3 between tumor and normal tissues provides an opportunity for targeted radiopharmaceutical therapy to treat HCC, a leading cause of cancer-related deaths worldwide. Methods: DOTA-RYZ-GPC3 (RAYZ-8009) comprises a novel macrocyclic peptide binder to GPC3, a linker, and a chelator that can be complexed with different radioisotopes. The binding affinity was determined by surface plasma resonance and radioligand binding assays. Target-mediated cellular internalization was radiometrically measured at multiple time points. In vivo biodistribution, monotherapy, and combination treatments with 177Lu or 225Ac were performed on HCC xenografts. Results: RAYZ-8009 showed high binding affinity to GPC3 protein of human, mouse, canine, and cynomolgus monkey origins and no binding to other glypican family members. Potent cellular binding was confirmed in GPC3-positive HepG2 cells and was not affected by isotope switching. RAYZ-8009 achieved efficient internalization on binding to HepG2 cells. Biodistribution study of 177Lu-RAYZ-8009 showed sustained tumor uptake and fast renal clearance, with minimal or no uptake in other normal tissues. Tumor-specific uptake was also demonstrated in orthotopic HCC tumors, with no uptake in surrounding liver tissue. Therapeutically, significant and durable tumor regression and survival benefit were achieved with 177Lu- and 225Ac-labeled RAYZ-8009, as single agents and in combination with lenvatinib, in GPC3-positive HCC xenografts. Conclusion: Preclinical in vitro and in vivo data demonstrate the potential of RAYZ-8009 as a theranostic agent for the treatment of patients with GPC3-positive HCC.

Developmental activities of elite junior hockey players: an analysis of early sport specialization

Early sport specialization is a popular and contentious topic in the scientific literature and popular media. The lure of extrinsic rewards has led to increasing rates of specialization among young athletes, while expert recommendations promote multisport participation. The purpose of this study was to describe and analyze developmental activities of a group of elite junior hockey players in Canada. Within this context, elements of specialization were investigated in accordance with existing theoretical frameworks and long-term athlete development models to enhance the literature. Fifteen participants from the Ontario Hockey League completed quantitative retrospective interviews, detailing past sport and recreational activities. Thirty-one developmental milestones were assessed. Accumulated hours of activity were categorized in accordance with Côté's (1999) Developmental Model of Sports Participation, along with the number and types of sports in which they participated during childhood. Jayanthi et al.'s (2015) continuum was utilized to determine the age at which the athletes became moderately and highly specialized. Accrued hours of deliberate practice reported by participants increased from ages 6 to 16 years, as did competition in organized hockey games. Reported hours of deliberate play peaked at 9 years of age and decreased thereafter. Participants played a combined 16 sports other than hockey, ranging from an average of 2.0 at age 6, to a maximum average of 5.6 at 12 years old, and decreasing each year to 2.3 by age 15. The greatest number of hours in other sports was accumulated at 12 years of age. Using a three-point scale, participants considered themselves "highly specialized" at 14 years old; however, other quantitative indicators suggested this may have occurred at 12 years of age. Relative to previous research on early sport specialization, participants in this study spent more time practicing hockey, while ceasing hockey-specific play and other sports at younger ages. Despite a diverse sport history, hockey competition was initiated earlier than recommended, showing high levels of sport commitment as young as 9 years old. The early specialization path remains a popular trajectory among coaches, parents, and athletes in Canadian ice hockey.

Microbial Interspecies Associations in Fracture-Related Infection

OBJECTIVES

Describe co-occurrence or clustering of microbial taxa in fracture-related infections to inform further exploration of infection-related interactions among them.

DESIGN

Retrospective review.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

Four hundred twenty-three patients requiring surgical intervention for deep surgical site infection between January 2006 and December 2015.

INTERVENTION

None.

MAIN OUTCOME MEASUREMENT

Connection between microbial taxa.

RESULTS

Methicillin-resistant Staphylococcus aureus, methicillin-sensitive Staphylococcus aureus, and coagulase-negative Staphylococcus represented the majority of monomicrobial observations (71%). Gram-negative rods, gram-positive rods, and anaerobes presented more frequently in polymicrobial infections. Enterobacter, vancomycin-sensitive Enterococcus, and Pseudomonas are present in polymicrobial infections with the highest frequencies and represent the top 3 most important nodes within the microorganism framework, with the highest network centrality scores.

CONCLUSIONS

The present study indicates that there are common microbial taxa (Enterobacter, Enterococcus, and Pseudomonas) that tend to co-occur with other microbes greater than 75% of the time. These commonly co-occurring microbes have demonstrated interactive relationships in other disease pathologies, suggesting that there may be similar important interactions in fracture-related infections. It is possible that these microbial communities play a role in the persistently high failure rate associated with management of infection after trauma. Future studies are needed to study the intermicrobial interactions that explain the frequency at which taxa co-occur. Understanding and potentially disrupting these intermicrobial relationships could inform improvements in the treatment of established infections and in the prevention of infection in high-risk patients.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Abstract LBA005: Detection of KRAS amplification on extrachromosomal DNA (ecDNA) upon acquired resistance to KRASG12C inhibitors

The recent discovery and clinical validation of KRAS inhibitors (KRASi) has ushered in a new therapeutic approach to directly address the previously undruggable mutant KRAS-driven cancers. Unfortunately, as with other oncogene-directed therapies, acquired resistance to KRASi has been observed that is partially attributed to secondary mutations in KRAS and/or mutations or fusions in other mitogen-activated protein kinase (MAPK) signaling genes. Emerging evidence suggests that amplification of oncogenes on acentric extrachromosomal DNA (ecDNA) might constitute an important mechanism of rapid resistance to receptor tyrosine kinase (RTK) and MAPK targeting therapies. Therefore, we investigated whether resistance to KRASi monotherapy is mediated through an ecDNA mechanism. We previously noted focal gene amplification of KRAS and MET in recurrent tumors isolated from patients treated with the selective KRASG12C inhibitor, adagrasib. Analysis of next-generation sequencing (NGS) data from a patient tumor revealed evidence of circular DNA structures encompassing the KRAS locus. Consistent with this finding, interphase FISH analysis indicated the presence of KRAS amplifications on ecDNA in this adagrasib-treated patient tumor. To further interrogate this biology, we examined a genetically modified CT26 murine tumor model harboring KRASG12C alteration. Analogous to the clinical observations, both adagrasib as well as the recently approved KRASi sotorasib, induced transient tumor regressions that subsequently resumed growth following several weeks of continuous therapy. Strikingly, whole-genome sequencing data from isolated recurrent tumors revealed focal amplification of KRASG12C and metaphase FISH confirmed high levels of KRASG12C on ecDNA as compared to vehicle-treated samples. Further mechanistic studies are underway. Collectively, these observations implicate ecDNA as an important mediator of resistance to KRASi monotherapy and reinforce the critical need for novel therapeutic strategies to address ecDNA oncogene amplification-driven cancers.

Citation Format: Ryan J Hansen, Steven Horton, Julie Wiese, BellJohn Bibay, E.Lorena Mora-Blanco, Nam-Phuong Nguyen, Lars D Engstrom, David M Briere, Andres Calinisan, Peter Olson, Mark M Awad, Andrew J Aguirre, Jason Christiansen, Christian Hassig, Shailaja Kasibhatla. Detection of KRAS amplification on extrachromosomal DNA (ecDNA) upon acquired resistance to KRASG12C inhibitors [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr LBA005.

Twenty-Year Trends in Upper-Extremity Infections at a Single Urban Institution

Purpose

Methods

Results

Conclusions

Type of study/level of evidence

Identifying the Safe Zone in Arthroscopic Anterior Elbow Capsulectomy: A Cadaveric Study

The authors assessed the effects of forearm rotation on the proximity of the radial nerve and medial collateral ligament (MCL) to a proximal and a more distal arthroscopic anterior elbow capsulectomy. Arthroscopy was performed on 10 cadaveric specimens. Sutures were passed lateral to medial at the level of the radiocapitellar joint and at the proximal edge of the annular ligament. Dissection measured the distance to the radial nerve from the lateral starting point and to the MCL from the medial exit point in varying degrees of forearm rotation. The extent of brachialis muscle coverage of the radial nerve was documented. The distance from the starting point to the radial nerve increased in pronation at both levels. The medial extent of the capsulectomy remained a safe distance from the MCL. Brachialis muscle covered the radial nerve at both levels. Pronation increases the capsulectomy safe zone, including more distally, before encountering the radial nerve; the MCL is not at risk. [Orthopedics. 2020;43(5):e399-e403.].

FRI0649-HPR HYDROXYCHLOROQUINE PRESCRIBING AND OPHTHALMOLOGY SCREENING WITHIN RHEUMATOLOGY DEPARTMENTS IN THE NORTH-WEST OF THE UNITED KINGDOM: A PROSPECTIVE REGIONAL AUDIT

Background:

Hydroxychloroquine (HCQ) is widely used in the management of rheumatoid arthritis and connective tissue disease. The prevalence of retinopathy in patients taking long-term HCQ is approximately 7.5%, increasing to 20-50% after 20 years of therapy. Hydroxychloroquine prescribed at ≤5 mg/kg poses a toxicity risk of <1% up to five years and <2% up to ten years, but increases sharply to almost 20% after 20 years. Risk factors for retinopathy include doses >5mg/kg/day, concomitant tamoxifen or chloroquine use and renal impairment. The UK Royal College of Ophthalmologists (RCOphth) 2018 guidelines for HCQ screening recommend optimal treatment dosage and timing for both baseline and follow-up ophthalmology review for patients on HCQ, with the aim of preventing iatrogenic visual loss. This is similar to recommendations made by the American Academy of Ophthalmology (2016).

Objectives:

To determine adherence to the RCOphth guidelines for HCQ screening within the Rheumatology departments in the North-West of the UK.

Methods:

Data for patients established on HCQ and those initiated on HCQ therapy were collected over a 7 week period from 9 Rheumatology departments.

Results:

473 patients were included of which 56 (12%) were new starters and 417 (88%) were already established on HCQ. 79% of the patients were female, with median ages of 60.5 and 57 years for new and established patients respectively. The median (IQR) weight for new starters was 71 (27.9) kg and for established patients, 74 (24.7) kg.

20% of new starters exceeded 5mg/kg daily HCQ dose. 16% were identified as high risk (9% had previously taken chloroquine, 5% had an eGFR <60ml/min/m2and 2% had retinal co-pathology). Of the high-risk group, 44% were taking <5mg/kg. In total, 36% of new starters were referred for a formal baseline Ophthalmology review.

In the established patients, 74% were taking ≤5mg/kg/day HCQ dose and 16% were categorized as high risk (10% had an eGFR less than 60ml/min/m2, 3% had previous chloroquine or tamoxifen use and 2% had retinal co-pathology). In the high-risk group, 75% were not referred for spectral domain optical coherence tomography (SD-OCT). 41% of patients established on HCQ for <5 years, and 33% of patients on HCQ for >5 years were not referred for SD-OCT. Reasons for not referring included; awaiting 5 year review, previous screening already performed and optician review advised.

Since the introduction of the RCOphth guidelines, 29% patients already established on HCQ had an alteration in the dosage of HCQ in accordance with the guidelines. In the high-risk group, 16% were not on the recommended HCQ dose.

Conclusion:

This audit demonstrates inconsistencies in adherence to the RCOphth guidelines for HCQ prescribing and ophthalmology screening within Rheumatology departments in the North-West of the UK for both new starters and established patients. Plans to improve this include wider dissemination of the guidelines to Rheumatology departments and strict service level agreements with ophthalmology teams to help optimize HCQ prescribing and screening for retinopathy.

Acknowledgments:

Drs. S Jones, E MacPhie, A Madan, L Coates & Prof L Teh. Co-1st author, T David.

Disclosure of Interests:

None declared

ApoC-III Glycoforms Are Differentially Cleared by Hepatic TRL (Triglyceride-Rich Lipoprotein) Receptors

OBJECTIVE

ApoC-III (apolipoprotein C-III) glycosylation can predict cardiovascular disease risk. Higher abundance of disialylated (apoC-III₂) over monosialylated (apoC-III₁) glycoforms is associated with lower plasma triglyceride levels. Yet, it remains unclear whether apoC-III glycosylation impacts TRL (triglyceride-rich lipoprotein) clearance and whether apoC-III antisense therapy (volanesorsen) affects distribution of apoC-III glycoforms. Approach and Results: To measure the abundance of human apoC-III glycoforms in plasma over time, human TRLs were injected into wild-type mice and mice lacking hepatic TRL clearance receptors, namely HSPGs (heparan sulfate proteoglycans) or both LDLR (low-density lipoprotein receptor) and LRP1 (LDLR-related protein 1). ApoC-III was more rapidly cleared in the absence of HSPG (t_1/2=25.4 minutes) than in wild-type animals (t_1/2=55.1 minutes). In contrast, deficiency of LDLR and LRP1 (t_1/2=56.1 minutes) did not affect clearance of apoC-III. After injection, a significant increase in the relative abundance of apoC-III₂ was observed in HSPG-deficient mice, whereas the opposite was observed in mice lacking LDLR and LRP1. In patients, abundance of plasma apoC-III glycoforms was assessed after placebo or volanesorsen administration. Volanesorsen treatment correlated with a statistically significant 1.4-fold increase in the relative abundance of apoC-III₂ and a 15% decrease in that of apoC-III₁. The decrease in relative apoC-III₁ abundance was strongly correlated with decreased plasma triglyceride levels in patients.

CONCLUSIONS

Our results indicate that HSPGs preferentially clear apoC-III₂. In contrast, apoC-III₁ is more effectively cleared by LDLR/LRP1. Clinically, the increase in the apoC-III₂/apoC-III₁ ratio on antisense lowering of apoC-III might reflect faster clearance of apoC-III₁ because this metabolic shift associates with improved triglyceride levels.

Management of symptomatic os acromiale: a survey of the American shoulder and elbow surgeons

BACKGROUND

The purpose of this paper was to survey members of the American Shoulder and Elbow Surgeons (ASES) to assess their opinion on management options, help highlight important clinical factors, and elucidate surgical preferences for the treatment of a symptomatic meso-os.

METHODS

An online questionnaire was distributed to the active members of the ASES. The survey queried surgeon demographics and perioperative management preferences, and presented multiple clinical case scenarios of patients with a presumed symptomatic, unstable os acromiale.

RESULTS

There were 116 ASES members who responded to the survey, and 26% (n = 30) who stated they do not operatively manage a symptomatic os. We identified two main clusters of respondents. Cluster 1 (n = 67) (as compared to cluster 2, n = 19) was comprised of surgeons with significantly more experience treating a symptomatic os acromiale (p < 0.05). These surgeons regarded gender, age, BMI, and hand dominance as important clinical factors when deciding when to proceed to surgery. Overall, arthroscopic management of the os was preferred, but those surgeons more experienced in treating os acromiale preferred open reduction and internal fixation (ORIF) in specific clinical cases.

CONCLUSION

The survey findings reflect the current lack of consensus in the treatment of a unstable, symptomatic os acromiale. Overall, arthroscopic management was preferred by most surgeons, though ORIF was preferred in certain clinical scenarios by those more experienced with os acromiale. The overall preference for arthroscopy suggests a possible shift in the treatment paradigm for patients with symptomatic meso-acromions, but higher level studies are needed to substantiate these findings.

Experience with the Jostra Rotaflow and QuadroxD oxygenator for ECMO

Since April 1988, we have been able to offer extracorporeal membrane oxygenation (ECMO) to patients who are either failing ventilation or who need cardiopulmonary support following cardiac surgery. During this time, we have supported 211 patients, the majority of whom have been supported with the Avecor (Affinity, Avecor Cardiovascular Inc., Minneapolis, MN, USA) spiral wound silicone-membrane oxygenator. Microporous hollow-fibre oxygenators have been used (18%) at our center. However, due to their early failure, they have necessitated conversion to a device that potentially would last for the entire ECMO course, i.e., Avecor and, subsequently, have not been used routinely until the introduction of the QuadroxD (Jostra Medizintechnik AG, Hirrlingen, Germany). The recent development of the poly-4-methyl-1-pentene diffusion membrane allows us to utilize hollow-fibre technology with a true (nonmicroporous) membrane. This has enabled us to use this low-resistance device with all its inherent advantages, without plasma leakage necessitating circuit changeover. From July 2000, we have used the QuadroxD oxygenator for our patients requiring ECMO support. This has been in patients with weights ranging from 2.16-51.0 kg ( n = 23), with the longest support being for 1119 hours. This new technology has enabled us to utilize a single device for all patient sizes, so we now have an ECMO circuit set up at all times, minimizing the time required for support to be available, potentially improving survivor morbidity.

Pump-induced haemolysis: a comparison of short-term ventricular assist devices

Centrifugal pumps are superior to roller pumps for extended support durations in terms of pump-induced haemolysis. In this study, we evaluated the commonly used Biomedicus BP 50 and compared it with the Jostra Rotaflow and a standard roller pump in an in vitro test circuit. Each circuit was run for a six-day period and repeated five times. Plasma haemoglobin values showed the roller pump to become more haemolytic than the Biomedicus ( p = 0.022) and the Rotaflow. A statistically significant difference between the Biomedicus and the Rotaflow was observed on day six of the trial ( p = 0.016), with the Rotaflow showing lower levels of haemolysis than the Biomedicus. These results support the use of the new generation centrifugal pump, the Rotaflow, as a suitable device for short-term ventricular assist.

Extracorporeal membrane modality conversions

We report the case of a patient with cardiovascular and respiratory failure due to severe anaphylaxis requiring multiple extracorporeal membrane oxygenation (ECMO) cannulation strategies to provide adequate oxygen delivery and ventilatory support during a period of rapid physiological change. ECMO provides partial or complete support of oxygenation-ventilation and circulation. The choice of which ECMO modality to use is governed by anatomical (vessel size, cardiovascular anatomy and previous surgeries) and physiological (respiratory and/or cardiac failure) factors. The urgency with which ECMO needs to be implemented (emergency cardiopulmonary resuscitation (eCPR), urgent, elective) and the institutional experience will also influence the type of ECMO provided. Here we describe a 12-year-old schoolgirl who, having been resuscitated with peripheral veno-venous (VV) ECMO for severe hypoxemia due to status asthmaticus in the setting of acute anaphylaxis, required escalation to peripheral veno-arterial (VA) ECMO for precipitous cardiovascular deterioration. Insufficient oxygen delivery for adequate cellular metabolic function and possible cerebral hypoxia due to significant differential hypoxia necessitated ECMO modification. After six days of central (transthoracic) VA ECMO support and 21 days of intensive care unit (ICU) care, she made a complete recovery with no neurological sequelae. The use of ECMO support warrants careful consideration of the interplay of a patient's pathophysiology and extracorporeal circuit dynamics. Particular emphasis should be placed on the potential for mismatch between cardiovascular and respiratory support as well as the need to meet metabolic demands through adequate cerebral, coronary and systemic oxygenation. Cannulation strategies occasionally require alteration to meet and anticipate the patient's evolving needs.

A comparison study of haemolysis production in three contemporary centrifugal pumps

One challenge in providing extracorporeal circulation is to supply optimal flow while minimising adverse effects, such as haemolysis. To determine if the recent generation constrained vortex pumps with their inherent design improvements would lead to reduced red cell trauma, we undertook a study comparing three devices. Utilizing a simulated short-term ventricular assist circuit primed with whole human blood, we examined changes in plasma free haemoglobin values over a six-day period. The three pumps investigated were the Maquet Rotaflow, the Levitronix PediVAS and the Medos Deltastream DP3.This study demonstrated that all three pumps produced low levels of haemolysis and are suitable for use in a clinical environment. The Levitronix PediVAS was significantly less haemolytic than either the Rotaflow (p<0.05) or the DP3 (p<0.05). There was no significant difference in plasma free haemoglobin between the Rotaflow and the DP3 (p=0.71).

Examining the relationship between relative age, competition level, and dropout rates in male youth ice-hockey players

The relative age effect suggests that athletes born in the first two quartiles of a given selection year experience a selection advantage and therefore a greater opportunity for success. We describe two studies examining the relationship between relative age, competition level, and dropout rates of Ontario Minor Hockey Association male ice-hockey players from ages 10 to 15 years (n = 14 325). In Study 1, dropout was highest among players born in quartiles three and four [χ(2) (3) = 16.32, P < 0.05; w = 0.06], while Study 2 found dropped out players to have less movement between competition levels compared to retained players. This study confirms a relationship between relative age and dropout from ice-hockey and adds further depth to our understanding of this persistent phenomenon.

Palliative care for dementia--time to think again?

It is estimated that there are 35.6 million people with dementia worldwide and this is projected to increase to over 115 million by the year 2050. Dementia is a progressive neurodegenerative disease that significantly reduces survival. End-of-life care received by this group is often poor and does not equate to that offered in other life limiting illnesses. This review highlights results from a large UK study of informal carers of people with dementia to explore what are determinants of care for people with dementia and their family carers. New perspectives as to models of care for end-of-life care for patients with dementia are discussed together with how these may be implemented and delivered within wider community settings and contexts, where many people with dementia may be cared for in the future.

A peer-led decision support intervention improves decision outcomes in black women with breast cancer

Previous reports suggest that Black breast cancer patients receive less patient-centered cancer care than their White counterparts. Interventions to improve patient-centered care (PCC) in Black breast cancer patients are lacking. Seventy-six women with histologically confirmed breast cancer were recruited from the Washington, DC area. After a baseline telephone interview, women received an in-person decision support educational session led by a trained survivor coach. The coach used a culturally appropriate guidebook and decision-making model-TALK Back!(©) A follow-up assessment assessed participants' acceptability of the intervention and intermediate outcomes. After the intervention, participants reported increased: self-efficacy in communicating with providers (70 %) and self-efficacy in making treatment decisions (70 %). Compared to baseline scores, post-intervention communication with providers significantly increased (p= .000). This is the first outcome report of an intervention to facilitate PCC in Black breast cancer patients. Testing this intervention using RCTs or similar designs will be important next steps.

Fetal left brachiocephalic vein in normal and abnormal conditions

OBJECTIVES

To establish values of fetal left brachiocephalic vein (LBCV) dimensions during normal pregnancy and determine whether routine assessment of the LBCV may help in identifying fetuses with congenital abnormalities of this vessel.

METHODS

Fetal LBCV was assessed prospectively during ultrasound examinations in 431 normal singleton pregnancies. The visualization rate of the transverse view of the upper fetal chest at the level of drainage of the LBCV into the superior vena cava (SVC) by two-dimensional (2D) and 2D plus color Doppler ultrasound was evaluated. Reference ranges of LBCV diameter during non-complicated pregnancies were established. Interobserver and intraobserver measurement variability was analyzed. In addition, a retrospective review of the hospital medical records of 91 pregnancies with fetuses diagnosed with LBCV abnormalities was performed.

RESULTS

Sonographic assessment of the fetal LBCV was consistently achieved in the second and third trimesters and in some fetuses in the first trimester of pregnancy. In normal fetuses LBCV diameter increased significantly throughout pregnancy, with a mean value of 0.7 mm at 11 weeks and 4.9 mm at term. Dilation of the fetal LBCV was noted in five cases of intracranial arteriovenous malformation and six cases of supracardiac type total anomalous pulmonary venous connection. Abnormal course of the LBCV was noted in 12 fetuses. In 63 fetuses with a persistent left SVC and a right SVC the LBCV was absent.

CONCLUSION

This is the first study describing an effective sonographic approach for the assessment of fetal LBCV dimensions during pregnancy. The normative data may provide an additional means of detecting rare anomalies of systemic and pulmonary veins during pregnancy.

Defining the fetal cardiac axis between 11 + 0 and 14 + 6 weeks of gestation: experience with 100 consecutive pregnancies

OBJECTIVE

The purpose of this study was to establish normal fetal cardiac axis values during the first and early second trimesters of pregnancy.

METHODS

This was a prospective observational cohort study in which the fetal cardiac axis was assessed during ultrasound examinations in 100 consecutive fetuses between 11 + 0 and 14 + 6 weeks of gestation. Transabdominal, and, when indicated, transvaginal, approaches were used. Intraobserver and interobserver reproducibility were calculated.

RESULTS

The cardiac axis ranged from 34.5 to 56.8° (mean (SD) 47.6 ± 5.6°) in 94 fetuses with normal cardiac anatomy. The fetal cardiac axis tended to be significantly higher in fetuses at 11 + 0 to 11 + 6 weeks of gestation than in fetuses at 12 + 0 to 14 + 6 weeks of gestation. Congenital heart defects were found in six out of 100 fetuses, four of which had abnormal cardiac axis values at 11 + 0 to 14 + 6 weeks of gestation.

CONCLUSION

Cardiac axis measurement is possible in the first and early second trimesters of pregnancy. The assessment of cardiac axis at an early gestational age may help to identify pregnancies at high risk for congenital heart defects. Copyright

Cross-contamination in the Molecular Detection of Bartonella from Paraffin-embedded Tissues

The genus Bartonella comprises a group of gram-negative, fastidious bacteria. Because of diagnostic limitations of culture and serologic testing, polymerase chain reaction (PCR) has become a powerful tool for the detection of Bartonella spp. in blood and tissue samples. However, because many wild and domestic animals harbor Bartonella spp., transfer of Bartonella DNA during sample collection or histologic processing could result in false-positive PCR test results. In this study, we describe evidence of Bartonella DNA dissemination and transfer in the necropsy room and during the subsequent processing of formalin-fixed paraffin-embedded tissues. Bartonella DNA was amplified from different areas of the necropsy room, from the liquid paraffin in the tissue processor, and from different parts of the microtome. Unless stringent procedures are established and followed to avoid cross-contamination, the molecular detection of Bartonella spp. from tissue samples obtained at necropsy or processed in a multispecies histopathology laboratory will not be reliable.

Clinical investigation of the novel iron-chelating agent, CP94, to enhance topical photodynamic therapy of nodular basal cell carcinoma

BACKGROUND

Photodynamic therapy (PDT) involves the activation of a photosensitizer by visible light to produce activated oxygen species within target cells, resulting in their destruction. Evidence-based guidelines support the efficacy of PDT using topical 5-aminolaevulinic acid (ALA-PDT) in actinic keratoses, Bowen disease and basal cell carcinoma (BCC). Efficacy for nodular BCC appears inferior to that for superficial BCC unless prior debulking or repeat treatments are performed. Objectives The aim of this study was to assess the safety and efficacy of adding a novel iron-chelating agent, CP94 (1,2-diethyl-3-hydroxypyridin-4-one hydrochloride), to topical ALA, to temporarily increase the accumulation of the photosensitizer in the tumour.

METHODS

A mixed topical formulation of ALA + increasing concentrations of CP94 was used to carry out PDT on previously biopsied nodular BCC with no prior lesion preparation using standard light delivery. The area was assessed clinically and surgically excised 6 weeks later for histological examination.

RESULTS

Enhanced PDT using 40% CP94 resulted in significantly greater clearance rates in nodular BCC than with ALA-PDT alone, in our protocol of single-treatment PDT with no lesion preparation.

CONCLUSIONS

The results of this study demonstrate the safe and effective use of an enhanced ALA-PDT protocol for nodular BCC using CP94, with no adverse reactions to this modification. This is the first time this formulation has been used in patients. This formulation is now the focus of further study.

Teaching and learning speech and language therapy skills: the effectiveness of classroom as clinic in speech and language therapy student education

BACKGROUND

Terms such as 'clinical intuition' have often been applied to the practice of speech and language therapy. Various authors have aimed to make the process of therapy practice more explicit, and it is argued that recently developed descriptive/analytic frameworks have the potential to engender the critical mindset necessary for student speech and language therapists to become good reflective practitioners, with the potential for enhancing clinical education.

AIMS

To investigate whether and how aspects of clinical skills education could be usefully addressed in an academic, as opposed to a clinical, setting. The study aimed to address the question of whether use of an interaction analysis system, in conjunction with video observation, and 'practice simulation' in a teaching-learning programme could be shown to have a positive impact on: (1) students' perceptions of their own understanding and practice of therapy, and their perceptions of themselves as self-reflective practitioners; and whether (2) this was borne out by students' ability to observe and interpret therapeutic interaction, as measured by (i) an objective written assessment; (ii) an objective video observation assessment; and (iii) assessment of their abilities in clinical practice.

METHODS & PROCEDURES

Thirty-six students from City University took part in an experimental, placebo-controlled study using a deferred intervention design. Assessments designed to reflect changes resulting from the teaching-learning curriculum were carried out pre- and post-intervention with experimental and control groups. Quantitative and qualitative results were obtained.

OUTCOMES & RESULTS

The intervention programme was found to have had a significant impact on students' perceptions of their understanding of therapy, but not on their perceptions of their practice of therapy. The experimental group scored significantly better on a written assessment of 'interpretation of therapy interaction', but were no better than the control group on a 'Video observation' assessment. Owing to attrition and the poor quality of videos submitted for assessment, it was not possible to measure changes in actual clinical practice. Qualitative feedback from the teaching-learning programme suggests that students generally found the approach to be beneficial.

CONCLUSIONS

While there were some encouraging results, it is still uncertain whether addressing the actual practice of therapy in an academic setting gives 'added value' to the work carried out on clinical placements. However, there is no doubt that bringing this type of programme under the umbrella of an academic institution would greatly increase the consistency of teaching and the range of experiences available to students.

East African running dominance revisited: a role for stereotype threat?

Regardless of the possible existence of physiological advantages in East African runners, belief that such differences exist creates a psychological atmosphere that can have significant consequences on performance. This is known as stereotype threat and can feature in many sports.

Massive left atrial calcification and devastating systemic emboli in a patient with chronic renal failure

Valvular calcification is a common consequence of systemic calcium deposition resulting from chronic renal failure. Thrombi can form on such vascular calcifications and embolize to the cerebral, myocardial, and mesenteric vasculature with devastating consequences. We report the unique case of a patient with myocardial and cerebrovascular ischemia resulting from emboli arising from a massive mitral annular calcification.

Trends in diet, nutritional status, and diet-related noncommunicable diseases in China and India: the economic costs of the nutrition transition

Undernutrition is being rapidly reduced in India and China. In both countries the diet is shifting toward higher fat and lower carbohydrate content. Distinct features are high intakes of foods from animal sources and edible oils in China, and high intakes of dairy and added sugar in India. The proportion of overweight is increasing very rapidly in China among all adults; in India the shift is most pronounced among urban residents and high-income rural residents. Hypertension and stroke are relatively higher in China and adult-onset diabetes is relatively higher in India. Established economic techniques were used to measure and project the costs of undernutrition and diet-related noncommunicable diseases in 1995 and 2025. Current WHO mortality projections of diet-related noncommunicable diseases, dietary and body composition survey data, and national data sets of hospital costs for healthcare, are used for the economic analyses. In 1995, China's costs of undernutrition and costs of diet-related noncommunicable diseases were of similar magnitude, but there will be a rapid increase in the costs and prevalence of diet-related noncommunicable diseases by 2025. By contrast with China, India's costs of undernutrition will continue to decline, but undernutrition costs did surpass overnutrition diet-related noncommunicable disease costs in 1995. India's rapid increase in diet-related noncommunicable diseases and their costs projects similar economic costs of undernutrition and overnutrition by 2025.

Commentary on "evidence that iron deficiency anemia causes reduced work capacity"

This commentary assesses the strength of the causal evidence presented by Haas and Brownlie in this supplement and examines the potential magnitude of iron-deficiency anemia on welfare. From both the laboratory and field experiments, the evidence is strong and suggests that the potential magnitude of the effect of iron-deficiency anemia on work productivity is substantial. This commentary briefly discusses some of the limitations of using the estimates of effects on physiological capacity for measuring the effect on the social and economic well-being of individuals and society. Biological data are relevant to social and economic development, but additional field studies may be as important as the laboratory experiments to answer questions that also affect work productivity, household maintenance and child raising activities, and hence affect social and economic development. We extend the critical evidence review of human field studies that received disproportionately less attention than the laboratory studies in Haas and Brownlie. We provide some estimates of the magnitude of effects on well-being based on how this information has been used. Future field studies that examine the effect of iron-deficiency anemia and work output in an economic sense should measure increases in productivity but should complement this information with data on wages, income or some measure of profits to derive a money metric measure of increased productivity. Additional information on individual time allocation in household work, child care and leisure may also be required to capture social benefits deriving from improved work capacity.

Neurogenin2 expression in ventral and dorsal spinal neural tube progenitor cells is regulated by distinct enhancers

The basic helix-loop-helix transcription factor Neurogenin2 (NGN2) is expressed in distinct populations of neural progenitor cells within the developing central and peripheral nervous systems. Transgenic mice containing ngn2/lacZ reporter constructs were used to study the regulation of ngn2 in the developing spinal cord. ngn2/lacZ transgenic embryos containing sequence found 5' or 3' to the ngn2 coding region express lacZ in domains that reflect the spatial and temporal expression profile of endogenous ngn2. A 4.4-kb fragment 5' of ngn2 was sufficient to drive lacZ expression in the ventral neural tube, whereas a 1.0-kb fragment located 3' of ngn2 directed expression to both dorsal and ventral domains. Persistent -gal activity revealed that the NGN2 progenitor cells in the dorsal domain give rise to a subset of interneurons that send their axons to the floor plate, and the NGN2 progenitors in the ventral domain give rise to a subset of motor neurons. We identified a discrete element that is required for the activity of the ngn2 enhancer specifically in the ventral neural tube. Thus, separable regulatory elements that direct ngn2 expression to distinct neural progenitor populations have been defined.

Examining interaction in language therapy

Discussions around a 'theory of therapy' have prompted attempts to delineate the components of therapy for language impairment in aphasia. Here it is suggested that the therapy components associated with how language therapy is enacted need more precise specification, especially in relation to what is entailed by interaction between therapist and person with aphasia. Presented too is a system used for the analysis of interaction in language impairment therapy for aphasia and its possible applications are discussed. Components of the system are described and a sample analysis presented. The methodological difficulties entailed in making comparisons of therapy enactment are discussed. It is suggested furthermore that unless more is known about precisely defined interactions in therapy, it will be difficult to answer basic questions not only about how language therapy is being carried out, but also, subsequently, whether the ways in which therapy tasks are enacted have a significant impact on the outcome.

Preoperative and postoperative considerations for carbon dioxide laser resurfacing

Cutaneous laser resurfacing is a tremendous advance in the treatment of photoaged skin. With the recent developments in laser technology, the procedure has become widely utilized among many physician subspecialists. The latest laser systems permit controlled vaporization of skin so that most novice operators feel comfortable with the technique in a short period of time. Nevertheless, there are many issues that need to be addressed before performing the procedure. First, not every person is an appropriate candidate for laser resurfacing. Second, both the physician and the patient must be aware of the preoperative preparation and prolonged postoperative care involved with the procedure. Finally, the physician must be able to identify and treat, and the patient must be educated about, the side effects and potential complications associated with the procedure. It is only by addressing these issues that the clinical results obtained by CO2 laser resurfacing can be maximized.

Safety and toxicity of nonoxynol-9 gel as a rectal microbicide

BACKGROUND AND OBJECTIVES

Methods of HIV and STD prevention, which can be controlled by the receptive partner, are a high priority for research and development. Studies on the safety of Nonoxynol-9 (N-9) on the vaginal mucosa have yielded conflicting results. No Phase I study has evaluated the effect of N-9 on the rectal mucosa.

GOALS

To assess the safety of 52.5 mg of N-9 in a 1.5-g gel when applied one to four applicators per day to the rectum and penis.

STUDY DESIGN

The study included 25 HIV-negative and 10 HIV-positive, monogamous gay male couples in which each partner was exclusively insertive or receptive while using N-9 gel. Each participant served as his own control during placebo gel use compared to during N-9 gel use. Receptive partners underwent anoscopic examination after 1 week of placebo use and after 2, 5, and 6 weeks of N-9 gel use, with rectal biopsies obtained after 1 week of placebo use and after 5 and 6 weeks of N-9 gel use. Insertive partners had safety monitoring after 1 week of placebo use and after 2, 5, and 6 weeks of N-9.

RESULTS

No rectal ulcers were detected; superficial rectal erosions were noted in two HIV-negative participants. Abnormal or slightly abnormal histologic abnormalities of rectal biopsies were detected in 31 (89%) receptive participants after N-9 gel use compared to 24 (69%) participants after 1 week of placebo gel use. Meatal ulceration, not caused by herpes simplex virus, was detected in one HIV-negative participant.

CONCLUSION

Low-dose N-9 gel was not associated with macroscopic rectal and penile epithelial disruption or inflammation, but histologic abnormalities were commonly observed during N-9 gel as well as during placebo gel use.