P–179 Timing of blastocyst observation on day 5: effect on the assessment to predict live birth, and the incorporation into a blastocyst selection model

Study question

Does variation in day 5 observation timing confound embryo-morphology-based live birth prediction, and is it possible to develop a robust comprehensive numerical prediction model.

Summary answer

Day 5 observation timing confounds embryo-morphology-based live birth prediction. A robust comprehensive numerical prediction model can be developed after considering a number of contributing variables.

What is known already

Embryo development is a dynamic process, and therefore the widely used static observations potentially lead to biased prediction of live birth outcomes. So far, little is known in regard to potential confounding impact of day 5 assessment timing on the static-morphology-based live birth prediction. In addition, the inter-observer variation in morphology-based embryo assessment requires a more robust system to improve consistency of selection.

Study design, size, duration

This retrospective multi-center cohort study included 8866 autologous oocyte in vitro fertilisation treatment cycles performed at 14 associated clinics within the same network during 2012–2018. Only fresh cycles with single day 5 embryo transfers were included for analysis with all pregnancies followed up until birth. Repeat cycles of same patients were excluded to avoid clustering effect in statistical analysis.

Participants/materials, setting, methods

Dataset was randomly split into two subsets at 60:40 ratio, with one (n = 5274) used for regression analysis and model development and the other (n = 3592) used for model testing. Multiple logistic regression was performed to evaluate live birth predicting power of several potential contributors, expressed by odds ratio (OR) and 95% confidence interval (CI). A comprehensive prediction model was subsequently developed based on calculated weights of contributing factors, then tested via receiver operating characteristics (ROC) analysis.

Main results and the role of chance

The timings of day 5 observation of 8866 included embryos, measured by hours post insemination (HPI), distributed in a bell shape ranging from 112.0 to 120.0 h (mean±SD 115.7±1.7 h). After taking into account female age at egg collection (grouped as < 30 yr, 30–34 yr, 35–39 yr, 40–44 yr, and 45 yr or older), whether or not the first egg collection, number of eggs collected, embryo developmental stage (grouped as pre-blastocyst, early blastocyst, expanding blastocyst, expanded blastocyst, and hatching/hatched blastocyst) and morphology score(A/B/C/D); multivariate logistic regression analysis showed significant association (OR 1.096, 95% CI 1.020–1.177, P = 0.012) between HPI groups (112–113.9 h, 114–115.9 h, 116–117.9 , and 118–120 h) and subsequent live birth outcomes. A comprehensive numerical scoring system was developed based on the statistically significant predictors including female age (OR 1.465, 95% CI 1.364–1.574, P = 0.000), embryo developmental stage (OR 1.341, 95% CI 1.244–1.445, P = 0.000), morphology score (OR 1.520, 95% CI 1.392–1.661, P = 0.000) and HPI (OR mentioned above); with a formula of Score = (Female_age_group/5)*1.465 + (Developmental_stage/5)*1.341 + (Morpho_Score/4)*1.520 + (HPI_Group/4)*1.096. ROC analysis showed statistically significant predictive power of the resulting model as expressed by area under the ROC curve using both the development (0.690, 0.675–0.704, P = 0.000) and testing (0.685, 0.667–0.703, P = 0.000) subsets.

Limitations, reasons for caution

The retrospective design does not allow for controlling of unknown confounders. HPI was based on static observations in this study so future time-lapse study may bring more insights with more accurate observation and measurement.

Wider implications of the findings: The varying HPIs at day 5 observation were alarming as this could confound live birth prediction using embryology parameters. It is important to standardise the timing of embryo observations. The inclusion of HPI into a comprehensive numerical scoring system for live birth prediction may potentially improve its robustness

Trial registration number

Not applicable

O-213 Slow day 5 development affects implantation potential of fresh transferred embryos but not birthweight once pregnancy occurs: A multi-center retrospective cohort study

Study question

Does slow development of fresh transferred day 5 embryos lead to decreased implantation potential and birthweight?

Summary answer

Slow day 5 development was associated with reduced implantation potential when transferred fresh but the subsequent birthweight of the resulting baby was not impacted.

What is known already

Slow development of in vitro cultured cleavage stage embryos is associated with reduced blastocyst development and implantation rates. There is no current consensus regarding whether to transfer fresh slow developing day 5 embryos or to extend culture for a subsequent day with potential for cryopreservation. It is therefore important to understand the true prognosis of fresh transferred day 5 embryos at less advanced developmental stages. This would provide evidence based guidelines for the decision making process in regard to embryo transfer.

Study design, size, duration

This is a retrospective multi-center cohort study, including 1213 consecutive patients undergoing autologous oocyte in vitro fertilization (IVF) treatment during 2016-2019,with fresh transfer of a single day 5 embryo (selection based on developmental stage and inner cell mass and trophectoderm morphology if blastocyst was at the ≥expanding stage). Cycle data were collected from 4 associated private clinics, with repeat cycles of same patients excluded to avoid clustering effect at statistical analysis.

Participants/materials, setting, methods

Live birth and birthweight were followed up in all 1213 fresh day 5 SETs. Multiple regression (logistic or linear) was performed to investigate association between slow day 5 development (defined as ≤ early blastocyst) and (a)live birth, (b) birthweight, and (c) gestation-adjusted birthweight (Z score) to account for gestational age, gender and compared to embryos at ≥ expanded stage. Results were expressed as adjusted odds ratio (aOR) with 95% confidence interval (CI)or coefficients (β).

Main results and the role of chance

No implantation was achieved following single fresh transfer of day 5 embryos that failed to reach early blastocyst stage (n = 76) and were transferred as ≤ morula stage. Live birth rate was significantly lower following single day 5 fresh transfer of an early blastocyst (n = 237, 16%), in comparison to expanding (n = 329, 27%, P = 0.001), expanded(n = 392, 41%, P = 0.000), and hatching/hatched blastocysts (n = 169, 44%, P = 0.000). After adjusting for potential confounding factors including; maternal age, hours post insemination at day 5 assessment, number of oocytes collected, number of 2PN embryos, and number of embryos frozen; multiple logistic regression showed significantly reduced likelihood of live birth resulting from early blastocysts in reference to those at the expanding (aOR=0.584, 0.371-0.917, P = 0.020), expanded (aOR=0.322, 0.208-0.501, P = 0.000), or hatching/hatched stages (aOR=0.255, 0.147-0.443, P = 0.000). However, multivariate linear regression indicated that early blastocysts resulting in a live birth (n = 39) did not lead to altered birthweight (β=-9.091, P = 0.904; β=-34.960, P = 0.343; β=-26.074, P = 0.414; respectively) or Z score (β = 0.045, P = 0.706; β=-0.051, P = 0.426; β=-0.028, P = 0.506; respectively) in reference to the expanding (n = 90), expanded (n = 160), or hatching/hatched stages (n = 75).

Limitations, reasons for caution

The retrospective nature of this study does not allow controlling of unknown confounders. The 4 participating clinics are associated within the same network with shared protocols, therefore, results may not be generalized to other clinics with different settings.

Wider implications of the findings

The findings suggest no clinical value of fresh day 5 transfer of embryos ≤morula stage. Although early blastocysts implant at reduced rate, assuring birthweight outcomes suggest clinical value. Future studies intend to investigate slow growing day 5 fresh transfers versus embryos that were slow growing but transferred after day 6.

Trial registration number

NA

P–191 Time-lapse videography reveals morphometric and morphokinetic differences in the pronuclei of male and female human zygotes

Study question

Do morphometric and morphokinetic profiles of pronuclei (PN) following intracytoplasmic sperm injection (ICSI) vary between male and female human zygotes?

Summary answer

Male and female zygotes displayed different PN morphometrics and morphokinetics. Additionally, variations were identified between sperm-originated (SPN) and oocyte-originated (OPN) pronuclei.

What is known already

Previous studies have investigated the use of PN-associated parameters via static observations as indicators of zygote viability, including size equality or juxtaposition. However, recent clinical application of time-lapse videography (TLV) provides a novel opportunity to assess these pronuclear events with greater accuracy and precision of morphometric and morphokinetic measurement. A number of recent TLV studies have also investigated potential live birth prediction by such PN associated measures, however whether or not there are gender associated differences in such measures which could in turn confound live birth prediction is unknown. Study design, size, duration: This retrospective cohort study included 94 consecutive autologous single day 5 transfer cycles (either fresh or frozen) performed between January 2019 and March 2020. Only ICSI cycles (maternal age <40 years) leading to a singleton live birth (43 males and 51 females) were included for analysis. All oocytes were placed in the EmbryoScope incubator for culture immediately post sperm injection with all annotation performed retrospectively by one embryologist (L-SO).

Participants/materials, setting, methods

Timings included 2nd polar body extrusion (tPb2), SPN(tSPNa)/OPN(tOPNa) appearance (differentiated by proximity to Pb2) and PN fading (tPNF). Morphometrics were evaluated at 8 (stage 1), 4 (stage 2) and 0 hour before PNF (stage 3), measuring PN area (um2), PN juxtaposition, and nucleolus precursor body (NPB) arrangement. Means ± standard deviation were compared using student t test or logistic regression as odds ratio (OR) and 95% confidence interval (CI), and proportional data by chi-squared analysis.

Main results and the role of chance

Logistic regression indicated that male zygotes had longer time intervals of tPb2_tSPNa than female zygotes (4.8±1.5 vs 4.2±1.0 h, OR = 1.442, 95% CI 1.009–2.061, p = 0.044), but not tPb2_tOPNa (4.7±1.8 vs 4.5±1.3 h, OR = 1.224, 95% CI 0.868–1.728, p = 0.250) and tPb2_tPNF (19.9±2.8 vs 19.1±2.3 h, OR = 1.136, 95% CI 0.957–1.347, p = 0.144). SPN increased in size from stage 1 through 2 to 3 (435.3±70.2, 506.7±77.3, and 556.3±86.4 um2, p = 0.000) and OPN did similarly (399.0±59.4, 464.3±65.2, and 513.8±63.5 um2, p = 0.000), with SPN being significantly larger than OPN at each stage (p < 0.05 respectively). However, relative size difference between SPN and OPN was similar between male and female zygotes at 3 stages (33.6±61.7 vs 38.6±50.8 um2, p = 0.664; 38.5±53.1 vs 45.7±71.9 um2, p = 0.585; 38.4±77.4 vs 45.8±63.9 um2, p = 0.615; respectively). More male than female zygotes reached central PN juxtaposition at stage 1 (77% vs 51%, p = 0.010), stage 2 (98% vs 86%, p = 0.048) and stage 3 (98% vs 86%, p = 0.048). Furthermore, more OPN showed aligned NPBs than in SPN at stage 1 (45% vs 29%, p = 0.023), but similar proportions at stage 2 (64% vs 50%, p = 0.056) and stage 3 (76% vs 72%, p = 0.618). There were no gender associated differences detected in NPB alignment in either SPN or OPN (p > 0.05 respectively).

Limitations, reasons for caution

The retrospective design does not allow for control of unknown confounders. Sample size is considered relatively small. PN area measurement may not truly represent volume as PN may not be perfectly spherical. Findings were based on women <40 years old so may not apply to older population.

Wider implications of the findings: These findings augment and extend previous studies investigating PN parameters via static observations. The reported variations between male and female embryos may confound live birth prediction when using pronuclei morphometrics and morphokinetics. Larger scaled studies are warranted to verify these findings.

Trial registration number

Not applicable

Changing paradigm of sacral neuromodulation and external anal sphincter repair for faecal incontinence in specialist centres

AIM

The aim of this study was to determine whether the paradigm of surgical intervention for faecal incontinence (FI) has changed between 2000 and 2013.

METHOD

This was a multi-centre retrospective study of patients who had undergone either sacral neuromodulation (SNM) or delayed sphincter repair or sphincteroplasty (SR) as a primary surgical intervention for FI in five centres in Europe and one in the United States. The flow of patients according to the intervention, sustainability of the treatment at a minimum follow-up of 5 years, complications and requirement for further interventions were recorded.

RESULTS

A total of 461 patients (median age 56 years, range 24-90 years, 41 men) had either SNM or SR as an index operation during the study period [SNM 284 (61.6%), SR 177 (38.4%)]. Among SNM patients, there were 169 revisional operations (change of battery and/or lead, re-siting or removal). At the time of last follow-up 203 patients (71.4%) continued to use SNM. Among SR patients, 30 (16.9%) had complications, most notably wound infection (22, 12.4%). During follow-up 32 patients (18.1%) crossed over to SNM. Comparing two 4-year periods (2000-2003 and 2007-2010), the proportion of patients operated on who had a circumferential sphincter defect of less than 90° was 48 (68%) and 45 (46%), respectively (P = 0.03), while those who had SNM as the primary intervention increased from 29% to 89% (P < 0.05).

CONCLUSION

The paradigm of surgical intervention for FI has changed with increasing use of SNM.

Number Needed to Treat with Vertebral Augmentation to Save a Life

BACKGROUND AND PURPOSE

Evidence from randomized controlled trials for the efficacy of vertebral augmentation in vertebral compression fractures has been mixed. However, claims-based analyses from national registries or insurance datasets have demonstrated a significant mortality benefit for patients with vertebral compression fractures who receive vertebral augmentation. The purpose of this study was to calculate the number needed to treat to save 1 life at 1 year and up to 5 years after vertebral augmentation.

MATERIALS AND METHODS

A 10-year sample of the 100% US Medicare data base was used to identify patients with vertebral compression fractures treated with nonsurgical management, balloon kyphoplasty, and vertebroplasty. The number needed to treat was calculated between augmentation and nonsurgical management groups from years 1-5 following a vertebral compression fracture diagnosis, using survival probabilities for each management approach.

RESULTS

The adjusted number needed to treat to save 1 life for nonsurgical management versus kyphoplasty ranged from 14.8 at year 1 to 11.9 at year 5. The adjusted number needed to treat for nonsurgical management versus vertebroplasty ranged from 22.8 at year 1 to 23.8 at year 5.

CONCLUSIONS

Both augmentation modalities conferred a prominent mortality benefit over nonsurgical management in this analysis of the US Medicare registry, with a low number needed to treat. The calculations based on this data base resulted in a low number needed to treat to save 1 life at 1 year and at 5 years.

Adult height, coronary heart disease and stroke: a multi-locus Mendelian randomization meta-analysis

Background: We investigated causal effect of completed growth, measured by adult height, on coronary heart disease (CHD), stroke and cardiovascular traits, using instrumental variable (IV) Mendelian randomization meta-analysis.

Methods: We developed an allele score based on 69 single nucleotide polymorphisms (SNPs) associated with adult height, identified by the IBCCardioChip, and used it for IV analysis against cardiovascular risk factors and events in 21 studies and 60 028 participants. IV analysis on CHD was supplemented by summary data from 180 height-SNPs from the GIANT consortium and their corresponding CHD estimates derived from CARDIoGRAMplusC4D.

Results: IV estimates from IBCCardioChip and GIANT-CARDIoGRAMplusC4D showed that a 6.5-cm increase in height reduced the odds of CHD by 10% [odds ratios 0.90; 95% confidence intervals (CIs): 0.78 to 1.03 and 0.85 to 0.95, respectively],which agrees with the estimate from the Emerging Risk Factors Collaboration (hazard ratio 0.93; 95% CI: 0.91 to 0.94). IV analysis revealed no association with stroke (odds ratio 0.97; 95% CI: 0.79 to 1.19). IV analysis showed that a 6.5-cm increase in height resulted in lower levels of body mass index (P < 0.001), triglycerides (P < 0.001), non high-density (non-HDL) cholesterol (P < 0.001), C-reactive protein (P = 0.042), and systolic blood pressure (P = 0.064) and higher levels of forced expiratory volume in 1 s and forced vital capacity (P < 0.001 for both).

Conclusions: Taller individuals have a lower risk of CHD with potential explanations being that taller people have a better lung function and lower levels of body mass index, cholesterol and blood pressure.

Visualization of in vivo septin ultrastructures by platinum replica electron microscopy

Septins are cytoskeletal proteins involved in diverse biological processes including cytokinesis, cell morphogenesis, motility, and ciliogenesis. Septins form various filamentous structures in vitro and in vivo, but the higher-order architecture of septin structures in vivo remains poorly defined. The best understood system in this respect is the budding yeast Saccharomyces cerevisiae, where septins form a ring structure that undergoes multiple stages of remodeling during the cell cycle. In this chapter, we describe a method for visualizing supramolecular septin structures in yeast at high spatial resolution using platinum replica electron microscopy. This approach can be applied to further understand the regulation of assembly and remodeling of septin higher-order structures, as well as the relationship between septin architecture and function.

Prevalence of BRCA1 mutations in women with triple-negative breast cancer: A systematic review

181

Background: We have reported a strong association between “triple-negative” breast cancer (TNBC) [estrogen receptor (ER) and progesterone receptor (PR) negative, HER2 negative] and the risk of having BRCA1 mutations in a meta-analysis. We hereby present a systematic review of a larger pool of specific data investigating the overall prevalence of BRCA1 mutations in women with TNBC.

Methods: A Medline search combining the MeSH terms “BRCA” and “triple” and “negative” yielded 37 articles. A similar search in ASCO abstracts yielded 18 relevant articles. Prevalence in each study population as well as the overall prevalence was calculated.

Results: 13 eligible studies (from year 2006 to 2011) including 1075 women with TNBC were identified. Out of 13, 1 study each was carried out on Ashkenazi Jewish and Hong Kong Chinese women respectively. Overall prevalence of BRCA1 mutations in women with TNBC is 20.93% (225 out of 1075) (range = 4.8%–43%). Ashkenazi Jewish women with TNBC have a higher-than-average prevalence of BRCA1 mutations (29.2%) although it is lower than the prevalence rates of some study populations. A remarkably low prevalence rate of BRCA1 mutations (4.8%) is found in Chinese women with TNBC.

Conclusions: In view of the overall high prevalence rate of BRCA1 mutations (20.93%) in women with TNBC, genetic testing should be discussed with patients with TNBC. Further studies are suggested to evaluate the molecular basis of interestingly low BRCA1 prevalence (4.8%) in Chinese patients with TNBC.

Risk of having BRCA mutations in women with triple-negative breast cancer: A systematic review and meta-analysis

160

Background: Increased prevalence of BRCA1 mutations (BRCA1) has been associated with the occurrence of triple-negative breast cancer (TNBC) (estrogen receptor [ER]- and progesterone receptor [PR]-negative, HER2-negative) in independent clinical studies. However, BRCA2 mutation (BRCA2) has not been found to overrepresent in women with TNBC. We have performed a meta-analysis of these studies to provide further statistical evidence of the association between BRCA positivity and TNBC.

Methods: A Medline search of the MeSH terms “BRCA”, “triple”, and “negative” yielded 37 articles. A search of ASCO abstracts yielded 18 relevant articles. Random effects model was used for analysis due to heterogeneity among the proportions of included studies (Cochran’s Q = 18.52 and 15.18, tau2 = 0.61 and 1.29, I2 = 73% and 80% for BRCA1 and BRCA2 respectively). Mantel-Haenszel method was applied to calculate the pooled event-based odds ratio (OR) with 95% confidence interval (CI).

Results: 6 studies including 1,602 BC patients were eligible for analysis of BRCA1 and 4 studies including 1297 BC patients for BRCA2. 172 patients with BRCA1 mutations and 79 patients with BRCA2 mutations were analyzed. Among these 6 studies, 1 included Ashkenazi Jewish women exclusively and 1 included only women of Chinese descent. The overall prevalence of BRCA1 was 10.05% (172 out of 1,602), and for TNBC patients 21.94% (95 out of 433) with an odds ratio of 5.90 (CI: 2.75, 12.66, p < 0.00001). TNBC was not a risk for BRCA2 (OR = 0.67, CI: 0.19, 2.39, p = 0.53). Chinese women with TNBC did not have an elevated risk of BRCA1 (OR = 0.94, CI: 0.24, 3.66) in contrast to Jewish women with TNBC who had the highest risk of BRCA1 among the populations studied (OR = 21.79, CI: 9.03, 52.55).

Conclusions: Women with TNBC carry a significantly high risk of having BRCA1 but not BRCA2 mutations. We recommend genetic testing for BRCA1 mutations in women with TNBC especially in Ashkenazi Jewish population. Further studies on Chinese population are needed to further establish the relationship between TNBC and BRCA1 mutations in this cohort.

Child health, developmental plasticity, and epigenetic programming

Plasticity in developmental programming has evolved in order to provide the best chances of survival and reproductive success to the organism under changing environments. Environmental conditions that are experienced in early life can profoundly influence human biology and long-term health. Developmental origins of health and disease and life-history transitions are purported to use placental, nutritional, and endocrine cues for setting long-term biological, mental, and behavioral strategies in response to local ecological and/or social conditions. The window of developmental plasticity extends from preconception to early childhood and involves epigenetic responses to environmental changes, which exert their effects during life-history phase transitions. These epigenetic responses influence development, cell- and tissue-specific gene expression, and sexual dimorphism, and, in exceptional cases, could be transmitted transgenerationally. Translational epigenetic research in child health is a reiterative process that ranges from research in the basic sciences, preclinical research, and pediatric clinical research. Identifying the epigenetic consequences of fetal programming creates potential applications in clinical practice: the development of epigenetic biomarkers for early diagnosis of disease, the ability to identify susceptible individuals at risk for adult diseases, and the development of novel preventive and curative measures that are based on diet and/or novel epigenetic drugs.

Metabolism, nitrogen excretion, and heat shock proteins in the central mudminnow (Umbra limi), a facultative air-breathing fish living in a variable environment

The central mudminnow ( Umbra limi (Kirtland, 1841)) is a continuous, facultative air-breathing freshwater fish found in swamps of central Canada and northeastern USA. The first goal of this field and laboratory-based study was to characterize the physicochemical conditions of mudminnow habitat during the summer. Our second goal was to determine the metabolic, stress response, and nitrogen excretion strategies of this fish following variations in water temperature, dissolved oxygen, external ammonia, and short-term periods of air exposure. We report profound diurnal fluctuations in water temperature (13–31 °C), dissolved oxygen (2%–159% air saturation), and ammonia levels (10–240 μmol·L−1) in habitat of central mudminnow measured on three dates at six different sites over 24 h. The central mudminnow does not induce urea synthesis as a mechanism of ammonia detoxification, either in response to emersion (6 or 20 h) or elevated external ammonia (10 mmol·L–1). Acute exposure to high temperature (~31 °C), aquatic hypoxia, or air resulted in significant increases in blood glucose and liver heat shock protein (Hsp) 70 and hypoxia also caused an increased reliance on anaerobic metabolism. This is the first description of the heat shock response in a facultative air-breathing fish following either hypoxia or air exposure. These metabolic and molecular responses are part of a strategy that allows the mudminnow to thrive in extremely variable freshwater environments.

Application of Magnetoelastic Thick Films for Wireless, In Vivo Monitoring of Pressure at Abdominal Aortic Aneurysm

According to the National Center for Health Statistics, cardiovascular diseases remain the number one killer in the United States. Among the various types of cardiovascular diseases, the aortic aneurysm is ranked number nine. The abdominal aortic aneurysm (AAA), in particular, is an abnormal, localized dilation of the abdominal aorta wall caused by weakened or diseased aorta walls. One of the treatments for this disease is using an endovascular surgery at which an endovascular graft is delivered to the aneurysm site through the femoral arteries. The deployment of the endovascular graft will exclude blood flow to the aneurysm, thus preventing further expansion of the aneurysm sac. Although this technique is preferred over open surgeries due to its minimal invasiveness, an event known as the endoleak, where the endovascular graft fails to retain the blood and leads to leakage to the aneurysm sac, may occur. Here, we are developing a novel pressure monitoring system to remotely and continuously measure the pressure in the aneurysm sac. The main component of the system is a pressure-sensitive material, made of a magnetoelastic, magnetically soft film attached or coated on the endovascular graft. When under an AC magnetic field (excitation field), the magnetoelastic film generates a secondary magnetic field. Due to its magnetoelastic property, the amplitude of the secondary field varies with applied stresses, allowing remote pressure monitoring. To eliminate noises from the excitation field, the generated secondary field is measured at twice the excitation frequency to obtain the 2nd-order harmonic field, which is used for tracking the pressure variations. A scaled-up prototype of the pressure monitoring system was constructed and examined to demonstrate the feasibility of this technology. A commercial magnetoelastic thick film, Metglas 2826MB from Metglas, Inc., was attached on a polycarbonate substrate and covered by a thin polycarbonate protective layer. The substrate was then embedded in a plastic tube with flowing liquid to represent the condition of an aorta. Liquid pressure in the tube was altered during the experiment by restricting or relaxing the flow channel. In this study, a 10mm×40mm file (Film A) and a 5mm×40mm film (Film B) were fabricated and tested. The amplitude of the 2nd-order harmonic field produced by the films was inversely proportional to the fluid pressure. It was also shown that films with different sizes exhibited different signal sensitivity with the smaller film (Film B) exhibited greater sensitivity. This experiment indicates that feasibility of the pressure monitoring technology.

Bioactive Magnetoelastic Materials as Coatings for Implantable Biomaterials

Enhanced fibroblast activity at the soft tissue-implant interface can dramatically decrease the stability, function, and lifespan of biomedical implants such as bone anchored prostheses. Although bone anchoring systems dramatically improve prosthetic limb mechanical stability, uncontrolled fibrosis at the soft tissue-mounting post interface is a significant problem. The aberrant cell growth leads to irregular skin folds that prevent proper sealing to the bone anchoring post and also serves as a site for opportunistic infection and failure of the prosthetic system. We are developing a bioactive vibrational coating to control fibrous tissue overgrowth. The coating is based on a magnetoelastic (ME) material that can be set to vibrate at a predetermined amplitude and frequency using a controlled magnetic field. We hypothesize that small local vibrations can be used to selectively control cell adhesion and gene expression to promote and maintain functional stability at the implant-tissue interface. For bone anchored prostheses, the ME coating would be applied around the mounting post at the soft tissue interface. The specific aims of this work were to (1) modify the coating for use in contact with a biologic environment and (2) determine if local vibrational strain can efficiently control cell attachment to the coating without significantly influencing viability. First, two common biocompatible polymers, polyurethane and chitosan, were deposited as thin films on the ME coating to allow for its use in tissue culture. An indirect cytotoxicity test was used to determine fibroblast (L929) viability in media conditioned for 24 and 48 hours with uncoated, chitosan coated, and polyurethane coated ME materials. Results demonstrated that both polymer coatings returned cell survival to levels statistically indistinguishable from controls (cells cultured on tissue cultured polystyrene, TCP) with cell viability over 96% under all coating conditions. Second, the affect of local vibrations on cell adhesion was tested in vitro. A cell viability assay (Calcein-AM) followed by fluorescent imaging was used to quantify attachment and viability of fibroblasts cultured directly on the bioactive ME material. Results clearly indicated that controlled local vibrations can induce complete cell detachment from the ME material compared with non-vibrated controls at up to 72 hours post-seeding. Further, cells detached via applied vibrations showed no significant decrease in viability compared to adherent controls. These results suggest the potential for this novel coating to effectively control fibrous tissue overgrowth using the mild application of tunable local vibrations, a significant and cost-effective approach that could improve the stability, function, and lifespan of biomedical implants and reduce the need for surgical revision.

Real-Time, In Vivo Measurement of Contact Pressures at a Knee Arthroplasty

There is a need to measure contact pressures at the femoral component and tibia plate of a knee arthroplasty implant to determine the wear and tear of the polyethylene (PE) insert of the implant. Today, most pressure monitoring systems for knee arthroplasty implants are either limited to in vitro or intraoperative use, or cannot measure contact pressures at the polyethylene surface. Here, we are developing a wireless passive sensor system for measuring the contact pressure at the knee arthroplasty in vivo. The sensor system is made of a pressure-sensitive magnetic layer embedded under the top surface of a PE insert used for mapping the contact pressures with the femoral components. The pressure-sensing layer consists of a grid of pressure and stress sensitive magnetoelastic thin strips that alter their magnetic properties with applied force. Measurements are taken at pressure points located at the crossings of the grid. The magnetization of each sensing strip is remotely measured by using an AC magnetic field to excite the material to generate higher-frequency fields, which are then detected through external detection coils. The responses of these sensing strips are fed into an algorithm to determine the pressure loadings at all pressure points, which allows for real-time, in vivo determination of pressure profiles on the PE insert. By using an array of magnetoelastic sensing strips, we have demonstrated the remote detection of pressure across a surface. The 2nd order harmonic amplitude of a 30 mm×1.5mm magnetoelastic strip decreased linearly with increasing pressure. For this sensing strip, the rate of decrease was about 0.1 (normalized to unstressed signal level) per 200 kPa. An algorithm was also developed to determine the pressures at all pressure points from the responses of the sensing strips. Experimental results have shown that the algorithm can accurately map the pressure profile of a 3×3 sensing strip array. Further works include developing a fabrication process for safely embedding the sensing strips into a PE insert, and modifying the algorithm for a larger sensing strip array.

A Wireless, Passive pH Sensor Based on Magnetic Higher-Order Harmonic Fields

A wireless, passive sensor was fabricated for remote monitoring of chemical analytes in the human body. The sensor was made of a magnetically soft film (sensing element) and a permanent magnetic film (biasing element) sandwiching a reversibly swelling hydrogel. When subjected to a low frequency magnetic AC field, the sensing element generated higher-order harmonic magnetic fields that were detected with a remotely located detection coil. In the presence of a DC magnetic field (biasing field), such as that generated from the biasing element, the pattern of the higher-order harmonic magnetic fields varied, and the magnitude of change (referred to as the harmonic field shift) was proportional to the strength of the biasing field. The hydrogel, which acted as a transducer that converted variations in the chemical concentration into changes in dimensions, physically varied the separation distance between the sensing and the biasing elements. This causes a change in the magnitude of biasing field experienced by the sensing element, thus changing its higher-order harmonic field shift allowing remote measurement of chemical concentrations. The novelty of this sensor was its wireless and passive nature, which allows it to be used inside a human body for long term chemical monitoring. A scaled-up prototype was fabricated and tested to demonstrate the pH monitoring capability of the sensor. The main structure of the prototype sensor was a polycarbonate substrate containing a larger rectangular well of 36mm×8mm×4mm on top of a smaller well of 30mm×5mm×2mm (see Fig. 1). The smaller well was filled with hydrogel made of (poly)vinyl alcohol and (poly)acrylic acid. A commercial magnetoelastic thick film, Metglas 2826MB from Metglas Inc., was attached to the step at the bottom of the larger well and allowed to rest on the hydrogel. The DC magnetic field was provided by an Arnokrome III film (Arnold Magnetic Technologies) of 30mm×6mm attached at the bottom of the sensor structure. The sensor was placed on the detection coil, and its response was measured with a spectrum analyzer while exposed to test solutions of varying pH. The sensor's harmonic field shift, when cycled between pH 7 and pH 3, was measured and plotted in Fig. 2. As shown in the figure, the hydrogel swelled when the sensor was exposed to pH 3, decreasing the harmonic field shift. The response and recovery times of the hydrogel were below 2 minutes. This experiment proves the feasibility of the technology for real-time, remote monitoring of pH. Further work includes improving the response time and sensitivity of the hydrogel, as well as miniaturization of the sensor.

Elevated blood pressure in overweight and obese Irish children

BACKGROUND

The Irish childhood obesity epidemic, one of the highest ranking internationally, represents a major threat to public health. We sought to perform a retrospective observational study of a clinic based cohort of obese Irish children.

METHODS

Clinical data relating to gender, age, height, weight, body mass index and blood pressure were analysed, from 206 children referred to a paediatric endocrine referral centre over a 15-year period for assessment of obesity.

RESULTS

Younger patients tended to have a higher standardised body mass index at initial presentation; 92% of boys and 96% of girls referred were obese (age-related BMI >/= 95th percentile). Boys (51%) and girls (49%) had initial blood pressure measurements in the hypertensive range. There was a correlation between the degree of obesity and systolic blood pressure, particularly in boys.

CONCLUSIONS

Obese Irish children present with significant long-term health risks, including hypertension at baseline.

The development of microalbuminuria is associated with raised longitudinal adiponectin levels in female but not male adolescent patients with type 1 diabetes

AIMS/HYPOTHESIS

We determined the longitudinal relationship between adiponectin levels and the development of microalbuminuria in an inception cohort of children with type 1 diabetes.

METHODS

Blood samples collected annually over a median of 9.0 (range 1.3-14.9) years were assayed for adiponectin and HbA(1c) in 55 children (36 girls) with type 1 diabetes and microalbuminuria whose age of onset of diabetes was 9.4 years (range 2.2-15.4). Samples were also assayed from normoalbuminuric children (controls) matched for age, sex and duration of diabetes.

RESULTS

Overall, adiponectin levels were higher in girls than in boys, but only after 11 years of age (median [range]: 15.3 [5.8-124.4] vs 11.6 [4.1-26.5] mg/l, p < 0.001). Furthermore, adiponectin levels were higher in girls with microalbuminuria than in control girls, but this was only apparent after the onset of microalbuminuria (p = 0.001, adjusted for BMI, daily insulin dose, HbA(1c) and age). In boys, adiponectin levels did not differ between those with microalbuminuria and controls. Further sex-related discordant associations with adiponectin levels were observed; in girls, adiponectin levels were positively related to HbA(1c) levels (r = 0.2, p = 0.05) and urine albumin excretion (r = 0.3, p < 0.05) and inversely related to BMI (r = -0.2, p < 0.05). These associations were absent in boys.

CONCLUSIONS/INTERPRETATION

In adolescent girls with type 1 diabetes but not in boys, adiponectin levels increase with increasing urine albumin excretion and onset of microalbuminuria. Although causal links cannot be inferred, this sexual dimorphism may reflect interactive effects of hyperglycaemia and sex steroids on risk of complications and adiponectin production.

Shoot Blight Caused by Diplodia pinea on Afghan and Austrian Pines in Texas

Shoot blight was observed on ornamental Afghan (Pinus eldarica) and Austrian pines (P. nigra) at several sites in metropolitan Dallas, TX in the summer of 2005. Shoots were stunted, cankered, often resinous, sometimes curled or crooked at the tips, and bore brown needles that often had been killed before full elongation. Pycnidia on necrotic needles, stems, and cones of each host species yielded conidia characteristic of the fungus Diplodia pinea. Individual conidia and hyphal tip transfers produced pure cultures confirmed as D. pinea using a species-specific PCR assay (1), which allows differentiation from the similar pine shoot blight pathogen D. scrobiculata. Five isolates (three from Afghan pine and two from Austrian pine) were tested for pathogenicity by inoculation of potted 1-year-old Afghan pine seedlings obtained from the Texas Forest Service Nursery. Elongating terminal shoots were wounded by removing a needle pair approximately 2 cm below the shoot apex. A 4-mm-diameter plug cut from an actively growing culture on water agar (WA) was placed fungus side down on the wound. Noncolonized WA plugs were placed on similarly wounded control seedlings. Nonwounded control seedlings also were used. Parafilm was wrapped around the shoots to hold the agar plugs in place and was removed 2 weeks later. Each treatment was applied to four seedlings. Five weeks after inoculation, 9 of the 20 inoculated seedlings (including at least one inoculated with each isolate) exhibited dieback of shoot tips. One wounded control seedling exhibited slight tip dieback, no other nonwounded or wounded control seedlings developed symptoms. Segments of shoots were harvested, surface disinfested, and incubated on WA to determine the presence of the pathogen. The pathogen was reisolated from 11 of the 20 inoculated seedlings but not from any control seedlings. To our knowledge, this is the first report of D. pinea as a cause of shoot blight of Afghan pine and the first substantiated report of the occurrence of D. pinea in Texas. Although widely distributed in much of eastern North America, reports of the presence of D. pinea in the other southern gulf coast states of Alabama, Louisiana, and Mississippi, as well as the western states of Colorado, New Mexico, and Utah, are lacking. Reference: (1) D. R. Smith and G. R. Stanosz. Plant Dis. 90:307, 2006.

Myelolipoma within a non-functional adrenal cortical adenoma

Myelolipoma within an adrenal cortical adenoma is a very rare cause of adrenal incidentaloma, and only nine cases have been reported in the English and Japanese literature. We report a 66-year-old Chinese man, with a history of hypertension and hyperlipidaemia, who presented with lower limb oedema and had a computed tomography (CT ) of the abdomen done to exclude intra-abdominal mass. His lower limb symptoms resolved after switching his antihypertensive medication. CT of the abdomen showed a large heterogeneously-enhancing mass in the left suprarenal region, measuring 72 mm by 55 mm. Clinical history, physical examination and laboratory results did not show any evidence to suggest metabolic disorder such as Cushing's syndrome, hyperaldosteronism or catecholamine hypersecretion. The patient underwent a left adrenalectomy, and a histopathological study confirmed the mass to be a non-functional adrenal cortical adenoma containing myelolipoma. The patient was well postoperatively and was discharged uneventfully. To the best of our knowledge, this is the first non-functional adrenal cortical adenoma reported; in the nine cases of myelolipoma within an adrenal cortical adenoma reported previously, all the patients had Cushing's syndrome. The literature on synchronous myelolipoma with adrenal adenoma, and myelolipoma within functional adrenal adenoma, is reviewed.

Technical inadequacies of peripheral contrast-enhanced magnetic resonance angiography: incidence, causes and management strategies

AIM

To assess the incidence, causes and effects of technical inadequacies in peripheral contrast-enhanced magnetic resonance angiography (CE-MRA) and to discuss relevant management strategies.

MATERIALS AND METHODS

A retrospective analysis of 249 peripheral CE-MRA examinations was performed using the radiology department's RIS/PACS (radiology information system/picture archiving and communication system) database. All failed or technically inadequate MRAs were reviewed. In cases that underwent further imaging by conventional angiography (CA), we assessed if relevant arterial disease had been masked on the MRA.

RESULTS

Of the 249 examinations, 215 (86.3%) were technically satisfactory while 34 (13.7%) were a combination of technical inadequacies [29 cases (11.6%)] and examination failures [five cases (2%)]. The causes of technical inadequacies were: (1) venous contamination (13 cases; 5.2%), (2) motion-induced subtraction artefact (eight cases; 3.2%), (3) stent-induced artefact (four cases; 1.6%), (4) inadequate scan coverage (two cases; 0.8%), and (5) contrast timing error (two cases; 0.8%). The causes of failed examinations were: (1) inability to tolerate lying in the scanner (three cases; 1.2%) and (2) inability to fit into the scanner (two cases; 0.8%). Fifteen (44.1%) of the 34 cases underwent further imaging by CA, and in eight of these there was significant arterial disease that was missed on the MRA.

CONCLUSION

Technical inadequacies occur in a small but significant proportion of peripheral CE-MRAs and can mask significant arterial disease. Knowledge of the potential causes of technical problems and the relevant management options is important for quality assurance and for limiting the need for an alternative investigation.

Feasibility and accuracy of 64-row MDCT coronary imaging from a centre with early experience: a review and comparison with established centres

The accuracy of multi-detector computed tomographic (MDCI) coronary angiography (CTA) is dependant on image quality as well as the experience of the operator. Established centers have reported negative predictive values of over 95%. The aim of our study was to investigate the accuracy and feasibility of CTA for the assessment of haemodynamically significant coronary stenosis in a center with very early experience (<6 months) utilizing the improved spatial and temporal resolutions of the latest generation 64-row MDCI scanner. One hundred and twenty eight patients (93 male, 35 female; mean age 56.2 +/- 9.5 years) with suspected or known coronary artery disease underwent both CIA and conventional coronary angiographv (CCA). The sensitivity, specificity, positive (PPV) and negative (NPV) predictive values for stenoses > or =50% by CIA compared to CCA were 70%, 97%, 70% and 97% respectively. Evaluation of main and proximal segments in patients with good quality images (78% of patients) produced values of 94%, 95%, 74% and 99% respectively. The improved spatial and temporal resolutions of 64-row MJ) CT provided a high negative predictive value in assessing significant coronary artery stenosis even in a centre with very early experience. However, new centers embarking on CTA might not be able to reproduce the results reported by more experienced centers.