Observation of Skewed Electromagnetic Wakefields in an Asymmetric Structure Driven by Flat Electron Bunches

Relativistic charged-particle beams that generate intense longitudinal fields in accelerating structures also inherently couple to transverse modes. The effects of this coupling may lead to beam breakup instability and thus must be countered to preserve beam quality in applications such as linear colliders. Beams with highly asymmetric transverse sizes (flat beams) have been shown to suppress the initial instability in slab-symmetric structures. However, as the coupling to transverse modes remains, this solution serves only to delay instability. In order to understand the hazards of transverse coupling in such a case, we describe here an experiment characterizing the transverse effects on a flat beam, traversing near a planar dielectric lined structure. The measurements reveal the emergence of a previously unobserved skew-quadrupolelike interaction when the beam is canted transversely, which is not present when the flat beam travels parallel to the dielectric surface. We deploy a multipole field fitting algorithm to reconstruct the projected transverse wakefields from the data. We generate the effective kick vector map using a simple two-particle theoretical model, with particle-in-cell simulations used to provide further insight for realistic particle distributions.

Phase Space Reconstruction from Accelerator Beam Measurements Using Neural Networks and Differentiable Simulations

Characterizing the phase space distribution of particle beams in accelerators is a central part of understanding beam dynamics and improving accelerator performance. However, conventional analysis methods either use simplifying assumptions or require specialized diagnostics to infer high-dimensional (>2D) beam properties. In this Letter, we introduce a general-purpose algorithm that combines neural networks with differentiable particle tracking to efficiently reconstruct high-dimensional phase space distributions without using specialized beam diagnostics or beam manipulations. We demonstrate that our algorithm accurately reconstructs detailed 4D phase space distributions with corresponding confidence intervals in both simulation and experiment using a limited number of measurements from a single focusing quadrupole and diagnostic screen. This technique allows for the measurement of multiple correlated phase spaces simultaneously, which will enable simplified 6D phase space distribution reconstructions in the future.

Fabrication of THz corrugated wakefield structure and its high power test

We present overall process for developing terahertz (THz) corrugated structure and its beam-based measurement results. 0.2-THz corrugated structures were fabricated by die stamping method as the first step demonstration towards GW THz radiation source and GV/m THz wakefield accelerator. 150-[Formula: see text]m thick disks were produced from an OFHC (C10100) foil by stamping. Two types of disks were stacked alternately to form 46 mm structure with [Formula: see text] 170 corrugations. Custom assembly was designed to provide diffusion bonding with a high precision alignment of disks. The compliance of the fabricated structure have been verified through beam-based wakefield measurement at Argonne Wakefield Accelerator Facility. Both measured longitudinal and transverse wakefield showed good agreement with simulated wakefields. Measured peak gradients, 9.4 MV/m/nC for a long single bunch and 35.4 MV/m/nC for a four bunch trains, showed good agreement with the simulation.

Predictors of steroid-refractory immune checkpoint inhibitor associated myocarditis

Background/Introduction

Immune checkpoint inhibitor (ICI)-associated myocarditis has a high mortality rate of approximately 50%. Clinical decompensation often occurs despite first-line treatment with corticosteroids. Factors associated with steroid failure are currently unknown.

Purpose

To identify predictors of steroid failure in patients with ICI-associated myocarditis.

Methods

We developed a web-based registry to collect and study 157 cases with clinical manifestations of ICI-associated myocarditis across 16 countries. Steroid failure was defined as patients who were escalated to immunomodulators after ≥1mg/kg daily dose of prednisone or had in-hospital death due to myocarditis despite ≥1mg/kg daily dose of prednisone. Steroid response was defined as all other patients treated with steroids without escalation to immunomodulators and without death due to myocarditis. A multivariate logistic model accounting for age and sex was used to predict association with steroid failure.

Results

Compared to steroid responsive cases, steroid failure was more likely to result in fulminant myocarditis (56.7% vs 19.6%, OR=5.37 [2.62–10.98] p<0.001) and all-cause in-hospital mortality (49.1% vs 12.9%, OR=6.50 [2.86–14.73] p<0.001) with shorter time from presentation to death (27.5 vs 43.0 days HR: 2.56 [1.45–4.50] p=0.001). When adjusting for age and sex, cases were more likely to be steroid-refractory if they were female (46.7% vs 30.1%, OR=2.77 [1.31–5.85] p=0.007), higher body mass index (27.2 vs 22.0, OR=1.09 [1.01–1.18] p=0.012), had higher intake creatine kinase (2800.5 vs 528.0 U/L, OR=1.48 [1.14–1.90] p=0.003) had higher intake troponin T (1.40 vs 0.25 ng/mL OR=1.63 [1.00–2.64] p=0.049), or had one or more concomitant non-cardiac immune-related adverse event (90.0% vs 74.2%, OR=3.10 [1.14–8.25] p<0.026). The only immune-related adverse events independently associated with steroid failure in myocarditis were myasthenia gravis-like syndrome (26.7% vs 8.2%, OR=3.84 [1.47–10.10] p=0.006) and myositis (45.0% vs 24.7%, OR=2.38 [1.16–4.92] p=0.018). Steroid failure was not significantly associated with cardiovascular or autoimmune history but was associated with a history of thymoma (12.0% vs 2.6%, OR=18.86 [0.10–356.7] p=0.05)

Conclusion(s)

Features such as female sex, high body mass index, and pre-existing thymoma as well as findings of elevated cardiac biomarkers and other non-cardiac immune-related adverse events – particularly myositis and myasthenia gravis-like syndrome – may represent a steroid-refractory phenotype of ICI-associated myocarditis. These results suggest that a multidisciplinary approach to diagnosing concomitant non-cardiac immune related adverse events is key to risk-stratifying ICI-associated myocarditis.

Forrest Plot

Funding Acknowledgement

Type of funding source: Private hospital(s). Main funding source(s): National Institutes of Health

Femoral neck cortical bone in female and male hip fracture cases: Differential contrasts in cortical width and sub-periosteal porosity in 112 cases and controls

OBJECTIVES

To quantitate differences between cases of hip fracture and controls in cortical width around the mid-femoral neck in men and women.

METHODS

Over 5 years, 64 (14 male) participants over age 55 (mean 79) years, who had never taken bone-active drugs and suffered intra-capsular hip fracture treated by arthroplasty, donated their routinely discarded distal intra-capsular femoral neck bone for histomorphometry. After embedding, complete femoral neck cross sections from the cut surface near the narrowest part of the neck were stained with von Kossa and cortical width was measured radially every 5 degrees of arc. Control material (n = 48, 25 male) was available through consented post mortems prior to the year 2000. Cortical widths were averaged for circumferential octants, each representing 45 degrees of arc. Divergence of individual cortical widths from their means was also examined.

RESULTS

Because sections were required to have a complete cortex, sampling was biased towards cases with sub-capital versus trans-cervical fractures. Compared to sex- and age matched controls, male cases showed larger relative differences in cortical widths than female cases. Unexpectedly, cortical widths in female but not male cases also showed marked over-representation of extremely narrow (<0.1 mm) cortical widths, located mainly posteriorly. The numbers of these very narrow cortical widths observed per subject retrospectively predicted female fracture status in logistic regression independently of mean cortical width values. Together with mean cortical width differences, the numbers of measured cortical widths <0.1 mm (out of 72 measured) raised the sensitivity of predicting fracture status in women from 48 to 80% at 80% specificity. In almost all cases, very narrow cortical widths were identified in regions enclosing a cortical pore roofed on its endosteal surface by thin structural bone defined a priori as trabecular.

CONCLUSIONS

Cortical widths <0.1 mm probably reflect zones where endosteal cortex has been trabecularised through expansion of an un-refilled sub-endosteal canal close to the periosteum. Persistent cortical defects occurring near the periosteal surface, where mechanical loading exerts its greatest stresses, are likely to result in extremes of localized concentrations of stress during a fall, unknown in young normal fallers. Such defects have the potential to help explain the excess of hip fractures among elderly women. Prevention of sub-periosteal tunnelling by osteoclasts might explain in part the additional benefits, beyond an increase in bone density, of treatments that reduce excessive bone resorption or else stimulate new bone formation on previously resorbed surfaces.

Ireland's recent contribution to the radiological literature; a bibliometric analysis

The aim of this study was to identify and analyse all articles published by Irish radiology departments in the medical literature since the year 2000. The PubMed database was searched to identify and review all articles published by radiologists based in the Republic of Ireland or Northern Ireland. Citation counts were then obtained and the top ten most cited articles were identified. There were 781 articles published during the study period. Of these, 558 (71%) were published in radiology journals and the remaining 223 (29%) were published in general medical journals. Abdominal radiology was the most represented sub-specialty (33% of all articles). There was a general trend of increased publications per year. Only 75 (9.6%) of articles were collaborative efforts by more than one radiology department. Irish radiology departments have a considerable research output and this has increased since the year 2000. More collaborative research between Irish radiology departments is encouraged.

Effect of fixation time on breast biomarker expression: a controlled study using cell line-derived xenografted (CDX) tumours

AIMS

Altering the length of time specimens are placed in fixative without compromising analytical testing accuracy is a continuous challenge in the anatomical pathology lab. The aim of this study was to determine under controlled conditions the effects of variable fixation time on breast biomarker expression in human breast cancer cell line-derived xenografted (CDX) tumours.

METHODS

CDX tumours using strong oestrogen receptor (ER)-positive, Her2-negative (MCF7) and weak ER-positive, Her2 equivocal (T47D) breast cancer cell lines were fixed for various times ranging from 1 to 336 hours in 10% neutral buffered formalin. CDX tumours were processed according to routine biomarker testing protocols and stained for ER and Her2 immunohistochemistry (IHC) and processed for HER2 fluorescence in situ hybridisation (FISH). The tumours were evaluated using Allred scoring for ER and current ASCO/CAP guidelines for Her2, and by objective cell counting methodology.

RESULTS

No differences were found in expression of ER in either MCF7 or T47D CDX tumours under variable fixation. T47D tumours displayed equivocal Her2 staining when fixed for 24 hours, but fixation for ≤8 hours resulted in consistently negative staining while tumours fixed for >72 hours demonstrated consistent equivocal staining (p<0.01). Cell counting assays revealed only a significant increase in sensitivity in tumours fixed for >72 hours (p<0.01). As expected, FISH results were unaffected by variable fixation.

CONCLUSIONS

Neither shortened nor prolonged fixation affects ER expression, consistent with previous findings. In equivocal Her2-expressing tumours, however, increasing fixation increased the sensitivity of Her2 IHC reporting while not affecting FISH.

Use of antiretroviral treatment among people living with HIV in Australia between 1997 and 2012

Current international targets aim for 90% of people diagnosed with HIV to be on antiretroviral treatment (ART). This paper aims to identify sociodemographic and attitudinal factors associated with ART non-use over time in three samples of Australian people living with HIV (PLHIV). Data for this paper were derived from an Australian cross-sectional survey of PLHIV that was repeated at three different time points: 1997, 2003, and 2012. There were approximately 1000 respondents to each survey (n = 3042 in total). The survey included approximately 250 items related broadly to health and well-being, ART use, and attitudes towards ART use. Univariate and multivariate logistic regression analyses were used. While the proportion of participants using ART increased between 1997 and 2012 (78.8-87.6%, p < .001), there was a decrease between 1997 and 2003 to 70.6% (p < .001). Factors linked to ART non-use remained steady over those 15 years. In all cohorts, people less likely to be using ART were younger and had a more recent diagnosis of HIV. In 2003 and 2012, people in full-time employment were less likely to be using ART, while those whose main source of income was a pension or social security were more likely to be using ART. Multivariate models showed that, at each time point, a belief in the health benefits of delayed ART uptake was associated with non-use. These findings suggest that there may be barriers to ART uptake that have persisted over time despite changes to clinical guidelines that now encourage early uptake.

The health perspectives of Australian adolescents from same-sex parent families: a mixed methods study

BACKGROUND

Research involving adolescents from same-sex parent families provides an important contribution to the evidence base on their health, well-being and the impact of stigma. To date reports on the perspectives of adolescents with same-sex attracted parents have been limited. This study aimed to describe the multidimensional experiences of physical, mental and social well-being of adolescents living in this context.

METHODS

A mixed methods study of adolescents with same-sex attracted parents comprising of an adolescent-report survey of 10- to 17-year-olds and family interviews with adolescents and their parents. Data were collected in 2012 and 2013 as part of the Australian Study of Child Health in Same-Sex Families.

RESULTS

The findings from qualitative interviews with seven adolescents and responses to an open-ended survey question (n = 16) suggest four themes: perceptions of normality, positive concepts of health, spheres of life (including family, friends and community) and avoiding negativity. The quantitative sample of adolescents with same-sex attracted parents (n = 35) reported higher scores than population normative data on the dimensions general health and family activities within the Child Health Questionnaire (CHQ) as well as higher on the peer problems scale on the Strengths and Difficulties Questionnaire (SDQ). Perceived stigma correlates with lower health and well-being overall.

CONCLUSIONS

Positive health outcomes are informed by the ways adolescents conceptualize health and how they construct their spheres of life. Peer relationships, and community perspectives of same-sex families, inform perceived stigma and its correlation with poorer health and well-being. Although adolescents see their families as essentially normal they are negatively affected by external societal stigma.

Bone marrow levels of 25 hydroxy vitamin D are not depressed in cases of hip fracture compared with controls

There is little information on tissue as distinct from plasma levels of vitamin D metabolites in cases of hip fracture compared with controls. Femoral neck fractures in the elderly are associated with increased cortical remodelling and endosteal resorption, leading to regional increases in porosity and reduced cortical thickness. Vitamin D metabolites play a central role in the maintenance of normal serum calcium levels and may, through interactions with parathyroid hormone, exert an important influence on bone structure. To investigate whether hip fracture might be associated with tissue vitamin D deficiency, we have measured by radioimmunoassay the levels of 25 hydroxy vitamin D (25 (OH)D) in bone marrow samples extracted from the proximal femurs of 16 female subjects who had suffered fracture (mean age = 82.1 years, standard error (se) 1.9) and nine sex matched post mortem controls (mean age = 83.8 years, se 2.5). Twenty five (OH)D concentrations were significantly greater in the fracture cases (median = 3.7, IQR = 2.5-3.9 ng/g) than in the control group (median = 1.5, IQR = 0.9-2.3 ng/g; P = 0.0007, non-parametric Wilcoxon/Kruskal-Wallis test). It was suggested in the 1970s that bone loss and hip fracture risk in the UK were driven by vitamin D deficiency. Our results suggest that the alterations in femoral neck bone microstructure and remodelling in hip fracture cannot be assigned to the single cause of relative deficiency of vitamin D. Vitamin D deficiency or insufficiency may nevertheless increase remodelling and loss of bone tissue and contribute causally to a minority of hip fractures.

Fourier transform infrared imaging of femoral neck bone: reduced heterogeneity of mineral-to-matrix and carbonate-to-phosphate and more variable crystallinity in treatment-naive fracture cases compared with fracture-free controls

After the age of 60 years, hip fracture risk strongly increases, but only a fifth of this increase is attributable to reduced bone mineral density (BMD, measured clinically). Changes in bone quality, specifically bone composition as measured by Fourier transform infrared spectroscopic imaging (FTIRI), also contribute to fracture risk. Here, FTIRI was applied to study the femoral neck and provide spatially derived information on its mineral and matrix properties in age-matched fractured and nonfractured bones. Whole femoral neck cross sections, divided into quadrants along the neck's axis, from 10 women with hip fracture and 10 cadaveric controls were studied using FTIRI and micro-computed tomography. Although 3-dimensional micro-CT bone mineral densities were similar, the mineral-to-matrix ratio was reduced in the cases of hip fracture, confirming previous reports. New findings were that the FTIRI microscopic variation (heterogeneity) of the mineral-to-matrix ratio was substantially reduced in the fracture group as was the heterogeneity of the carbonate-to-phosphate ratio. Conversely, the heterogeneity of crystallinity was increased. Increased variation of crystallinity was statistically associated with reduced variation of the carbonate-to-phosphate ratio. Anatomical variation in these properties between the different femoral neck quadrants was reduced in the fracture group compared with controls. Although our treatment-naive patients had reduced rather than increased bending resistance, these changes in heterogeneity associated with hip fracture are in another way comparable to the effects of experimental bisphosphonate therapy, which decreases heterogeneity and other indicators of bone's toughness as a material.

Osteocyte recruitment declines as the osteon fills in: interacting effects of osteocytic sclerostin and previous hip fracture on the size of cortical canals in the femoral neck

There is little information on the distribution of osteocytes within the individual cortical osteon, but using direct 3-D imaging in a single subject, Hannah et al. found a gradient with a two-fold higher density of cells adjacent to the cement line compared to near the canal. Since a limiting factor for bone formation might be the availability of osteoblasts due to their recruitment as osteocytes, we studied distributions of osteonal osteocytes in frozen sections of the femoral neck cortex. Osteocytes were stained with an anti-sclerostin antibody and counter-stained with toluidine blue. Adjacent sections were stained for alkaline phosphatase (ALP). Each osteonal osteocyte was categorised as being sclerostin-positive (scl+) or negative (scl-). ImageJ was used to measure the perimeter and area of each osteon and canal, while special purpose routines were used to measure the minimum distances of each osteocyte from the cement line and the canal. Canal area was strongly correlated with osteon area. Osteocytes were most dense close to the cement line; and their areal density within the matrix declined up to three-fold between the cement line and the canal, depending on osteon diameter. Large and small osteons had similar densities of osteocytes close to the cement line, but fractured neck of femur cases had significantly lower densities of osteocytes close to the canal. Higher osteocyte density close to the canal was associated with ALP expression. It is concluded that entombment of osteocytes newly drawn from the osteoblast pool into the mineralising matrix is independent of preceding bone resorption depth. As osteonal infilling proceeds, osteocyte formation declines more rapidly than matrix formation, leading to a progressive reduction in osteocyte density. A shrinking supply of precursor osteoblasts due to previous osteocyte recruitment, apoptosis, or both could produce this effect. In a statistically significant contrast, sclerostin negative osteocytes adjacent to the canal had the expected effect of reducing canal size in controls but this was not seen in hip fracture. This demonstrated the failure of osteonal osteoblasts to sustain bone formation through a complete remodelling cycle in osteoporosis, perhaps due to insufficient osteoblasts remaining capable of mineralized matrix formation. The failure of osteocytic sclerostin suppression to associate with bone formation in these osteons might alternatively be explained by downstream interference with sclerostin's effect on wnt signalling.

Refractive and visual outcome of toric intraocular lens implantation following cataract surgery

PURPOSE

To evaluate the refractive and visual outcome of toric IOL implantation for correction of pre-existing corneal astigmatism following cataract surgery.

MATERIALS AND METHODS

In this retrospective study, 56 eyes of 30 patients who underwent implantation of toric IOL following regular phacoemulsification were divided into two groups based on the types of toric IOL implanted: group 1 patients received Acrysof toric (Alcon) and group 2 patients received AT-Torbi (Zeiss Meditech) IOLs. Pre-and post-operative corneal and refractive astigmatisms, and post-operative distance vision were investigated. Statistical analysis was carried out using the paired student t-test when necessary. Factors affecting the success of toric IOL implantation are discussed and recommendations are made to optimize the outcome.

RESULTS

The mean age of all patients was 75.56 � 9.87 years. No statistical difference was observed between pre-and post-operative corneal astigmatism (p = 0.819). Postoperative refractive astigmatism was significantly less in both groups (Group 1: p = 0.0014; Group 2: p= less than0.00001). The best-corrected distance visual acuity was 6/12 or better in 95 % of group 1 and 100 % of group 2 patients.

CONCLUSION

Toric IOL implantation is a viable and highly predictable method of correcting the corneal astigmatism. It allows correction without compromising the integrity of the cornea. Careful selection of the patient, accurate keratometry and precise alignment of the cylindrical axes are some of the factors to be considered for a superior outcome.

Patients with sclerosteosis and disease carriers: human models of the effect of sclerostin on bone turnover

Sclerosteosis is a rare bone sclerosing dysplasia, caused by loss-of-function mutations in the SOST gene, encoding sclerostin, a negative regulator of bone formation. The purpose of this study was to determine how the lack of sclerostin affects bone turnover in patients with sclerosteosis and to assess whether sclerostin synthesis is decreased in carriers of the SOST mutation and, if so, to what extent this would affect their phenotype and bone formation. We measured sclerostin, procollagen type 1 amino-terminal propeptide (P1NP), and cross-linked C-telopeptide (CTX) in serum of 19 patients with sclerosteosis, 26 heterozygous carriers of the C69T SOST mutation, and 77 healthy controls. Chips of compact bone discarded during routine surgery were also examined from 6 patients and 4 controls. Sclerostin was undetectable in serum of patients but was measurable in all carriers (mean 15.5 pg/mL; 95% confidence interval [CI] 13.7 to 17.2 pg/mL), in whom it was significantly lower than in healthy controls (mean 40.0 pg/mL; 95% CI 36.9 to 42.7 pg/mL; p < 0.001). P1NP levels were highest in patients (mean 153.7 ng/mL; 95% CI 100.5 to 206.9 ng/mL; p = 0.01 versus carriers, p = 0.002 versus controls), but carriers also had significantly higher P1NP levels (mean 58.3 ng/mL; 95% CI 47.0 to 69.6 ng/mL) than controls (mean 37.8 ng/mL; 95% CI 34.9 to 42.0 ng/mL; p = 0.006). In patients and carriers, P1NP levels declined with age, reaching a plateau after the age of 20 years. Serum sclerostin and P1NP were negatively correlated in carriers and age- and gender-matched controls (r = 0.40, p = 0.008). Mean CTX levels were well within the normal range and did not differ between patients and disease carriers after adjusting for age (p = 0.22). Our results provide in vivo evidence of increased bone formation caused by the absence or decreased synthesis of sclerostin in humans. They also suggest that inhibition of sclerostin can be titrated because the decreased sclerostin levels in disease carriers did not lead to any of the symptoms or complications of the disease but had a positive effect on bone mass. Further studies are needed to clarify the role of sclerostin on bone resorption.

Sclerostin and the regulation of bone formation: Effects in hip osteoarthritis and femoral neck fracture

Remodeling imbalance in the elderly femoral neck can result in thin cortices and porosity predisposing to hip fracture. Hip osteoarthritis protects against intracapsular hip fracture. By secreting sclerostin, osteocytes may inhibit Wnt signaling and reduce bone formation by osteoblasts. We hypothesised that differences in osteocytic sclerostin expression might account for differences in osteonal bone-formation activity between controls and subjects with hip fracture or hip osteoarthritis. Using specific antibody staining, we determined the osteocytic expression of sclerostin within osteons of the femoral neck cortex in bone removed from subjects undergoing surgery for hip osteoarthritis (hOA: 5 males, 5 females, 49 to 92 years of age) or hip fracture fixation (FNF: 5 males, 5 females, 73 to 87 years of age) and controls (C: 5 males, 6 females, 61 to 90 years of age). Sclerostin expression and distances of each osteocyte to the canal surface and cement line were assessed for all osteonal osteocytes in 636 unremodeled osteons chosen from fields ( approximately 0.5 mm in diameter) with at least one canal staining for alkaline phosphatase (ALP), a marker of bone formation. In adjacent sections, ALP staining was used to classify basic multicellular unit (BMUs) as quiescent or actively forming bone (ALP(+)). The areal densities of scl(-) and scl(+) osteocytes (number of cells per unit area) in the BMU were inversely correlated and were strong determinants of ALP status in the BMU. In controls and hip fracture patients only, sclerostin-negative osteocytes were closer to osteonal surfaces than positively stained cells. Osteon maturity (progress to closure) was strongly associated with the proportion of osteonal osteocytes expressing sclerostin, and sclerostin expression was the chief determinant of ALP status. hOA patients had 18% fewer osteocytes per unit bone area than controls, fewer osteocytes expressed sclerostin on average than in controls, but wide variation was seen between subjects. Thus, in most hOA patients, there was increased osteonal ALP staining and reduced sclerostin staining of osteocytes. In FNF patients, newly forming osteons were similar in this respect to hOA osteons, but with closure, there was a much sharper reduction in ALP staining that was only partly accounted for by the increased proportions of osteonal osteocytes staining positive for sclerostin. There was no evidence for a greater effect on ALP expression by osteocytes near the osteonal canal. In line with data from blocking antibody experiments, osteonal sclerostin appears to be a strong determinant of whether osteoblasts actively produce bone. In hOA, reduced sclerostin expression likely mediates increased osteoblastic activity in the intracapsular cortex. In FNF, full osteonal closure is postponed, with increased porosity, in part because the proportion of osteocytes expressing sclerostin increases sharply with osteonal maturation.

Bone structure and remodelling in stroke patients: early effects of zoledronate

INTRODUCTION

We have reported that after an acute stroke, intravenous zoledronate prevented bone loss in the hemiplegic hip. Participants from the trial also volunteered for trans-iliac bone biopsy, to assess the early effects of stroke and zoledronate on iliac bone remodelling.

METHODS

Patients with acute stroke were randomly assigned to a single intravenous dose of zoledronate 4 mg or placebo within 5 weeks of stroke. Biopsies from 14 patients (3 female, 11 male, mean age 71+/-11) were suitable for analysis. These were taken at mean 10 weeks (+/-2) post-stroke, and included 5 patients who had received zoledronate. Histomorphometry was performed on undecalcified sections using light and fluorescence microscopy. Static and dynamic indices of remodelling were compared to a local reference range from healthy controls. Osteoclasts and their precursors were identified on frozen sections using tartrate resistant acid phosphatase (TRAP) staining. Dual-energy x-ray absorptiometry (DXA) of the proximal femora was performed at baseline and 6 months later.

RESULTS

The eroded surface in cancellous bone (ES/BS) was significantly higher in stroke patients than controls (5.7% vs. ref 1.6%, p<0.0001). Although ES/BS did not differ between zoledronate and placebo-treated groups, there were significantly fewer osteoclasts and their precursors in zoledronate-treated individuals (p=0.023). Bone formation indices (osteoid surface, OS/BS and mineralising surface, MS/BS) were significantly lower in stroke patients than controls and although OS/BS was higher in the zoledronate group than the placebo group (p=0.033), MS/BS was not different (p=0.924). There were no differences between hemiplegic and unaffected sides for any histomorphometric parameter despite asymmetric reductions in hip bone mineral density (p=0.013).

CONCLUSION

Stroke patients had higher resorption indices and lower bone forming surfaces than controls, consistent with uncoupling of bone remodelling. These findings are preliminary and a larger study is required to evaluate the contributions of gender, age and hemiplegic status to the remodelling imbalance. Zoledronate therapy was associated with a reduction in osteoclastic cell numbers consistent with its known mode of action in bone.

Acceptability of chlamydia screening using self-taken vaginal swabs

In the first phase of the National Chlamydia Screening Programme (NCSP), the majority of sites involved offered testing with urine sample. Camden & Islington (C&l) were the first site to offer testing with self-taken vaginal swabs (SVS). SVS are appropriate specimens for diagnosing chlamydia by nucleic acid amplification tests. This study aimed to assess the uptake and acceptability of chlamydia screening using SVS within C&l contraceptive clinics. Data collected from women participating in the NCSP between June 2003 and April 2004 were analysed. Of the 3936 women who accepted screening, 90.4% provided a SVS and only 5.8% accepted the offer of providing a urine sample as an alternative to SVS. Women over 19 years and women from Asian ethnic groups were most likely to decline any screening. No woman stated a reluctance to provide a SVS as a reason for declining screening, confirming the acceptability of SVS for chlamydia screening.

Subdermal implantable contraceptives versus other forms of reversible contraceptives or other implants as effective methods of preventing pregnancy

BACKGROUND

Implantable methods of contraception offer long-acting reversible contraception. Their uptake rate in comparison to other contraceptive methods, particularly in developed countries, has historically been low.

OBJECTIVES

To assess the contraceptive effectiveness, tolerability and acceptability of subdermal implants in comparison to other reversible contraceptive methods.

SEARCH STRATEGY

Literature were identified through database searches, reference lists and individuals/organisations working in the contraceptive field.

SELECTION CRITERIA

All randomised and controlled trials comparing subdermal implants with other forms of reversible contraceptives and reporting on pre-determined outcomes in women of reproductive years. Primary outcomes were pregnancy and continuation.

DATA COLLECTION AND ANALYSIS

Quality assessment of studies and data extraction were completed independently by two reviewers. A quality checklist was designed to identify general methodological and contraceptive specific factors. Study authors and pharmaceutical companies were contacted to provide additional data.Data were collected on pregnancy rates, continuation, side effects and adverse events.

MAIN RESULTS

All nine identified trials compared different types of contraceptive implant. Eight, involving 1578 women, compared Implanon with Norplant , and one, involving 1198 women, compared Jadelle with Norplant. There was no difference between Implanon and Norplant for contraceptive effectiveness rates or continuation over 4 years. Both were highly effective methods of contraception with no pregnancies occurring in any of the trials during 26,972 and 28,108 women months of follow up respectively. The most common side-effect with Implanon and Norplant was changes in bleeding pattern. The pattern with Implanon was initially more variable, bleeding with both implants became less frequent with duration of use. After two years use the amenorrhoea rate was significantly higher with Implanon. The trials reported no significant difference in hormonal side-effects or adverse events. Implanon was significantly quicker to insert and remove than Norplant. There was no difference in contraceptive effectiveness and in continuation rates between Jadelle and Norplant. Jadelle was significantly quicker to remove than Norplant.

AUTHORS' CONCLUSIONS

Implanon, Norplant and Jadelle are highly effective contraceptive methods. No significant differences were found in contraceptive effectiveness or continuation. The most common side-effect with all implants was unpredictable vaginal bleeding. Time taken for removal of Implanon and Jadelle was less than that for Norplant.Although this systematic review was unable to provide a definitive answer on relative effectiveness, tolerability and acceptability of contraceptive implants in comparison to other contraceptive methods, it has raised issues around the conduct of contraceptive research.

Effects of static stretching volume and intensity on plantar flexor explosive force production and range of motion

AIM

The aim of the study was to determine the effects of volume and intensity of static stretching in a warm-up on explosive force production and range of motion (ROM) of the plantar flexors.

METHODS

Twenty subjects performed 5 warm-ups on different days. The warm-ups contained a 5 min treadmill run and various protocols of 30 s static stretches (SS) of the plantar flexors. Stretching involved dorsi flexion just before the pain threshold, which was considered 100% intensity. The treatments that immediately followed the run were: (i) no other treatment (control); (ii) 1 min SS; (iii) 2 min SS; (iv) 4 min SS; (v) 2 min SS at 90% intensity. Ankle ROM was assessed before and after each warm-up and a concentric calf raise and drop jump (DJ) test was conducted after each warm-up.

RESULTS

There were no significant differences (P > 0.05) in peak force or rate of force production in the explosive calf raise between any of the warm-ups. However the run plus 2 min stretch and the run plus 4 min stretch protocols produced significantly lower (P < 0.05) DJ performance (jump height/ground contact time) than the run. The run plus 4 min stretch warm-up also produced a significantly lower DJ score than the run plus 1 min stretch warm-up. There were no significant differences between any of the warm-ups in ankle ROM.

CONCLUSIONS

The addition of 2-4 min of SS at 100% intensity to a run caused an impairment to fast stretch shortening cycle muscle performance. The greater impairment from the 4 min stretching condition supported a volume-effect. Two minutes of stretching at 90% intensity had no significant influence on muscle function. The addition of up to 4 min of SS to a run had no appreciable effect on ankle ROM, possibly because of the prior influence of the run.

Novel techniques of laser acceleration: from structures to plasmas

Compact accelerators of the future will require enormous accelerating gradients that can only be generated using high power laser beams. Two novel techniques of laser particle acceleration are discussed. The first scheme is based on a solid-state accelerating structure powered by a short pulse CO(2) laser. The planar structure consists of two SiC films, separated by a vacuum gap, grown on Si wafers. Particle acceleration takes place inside the gap by a surface electromagnetic wave excited at the vacuum/SiC interface. Laser coupling is accomplished through the properly designed Si grating. This structure can be inexpensively manufactured using standard microfabrication techniques and can support accelerating fields well in excess of 1 GeV m(-1) without breakdown. The second scheme utilizes a laser beatwave to excite a high-amplitude plasma wave, which accelerates relativistic particles. The novel aspect of this technique is that it takes advantage of the nonlinear bi-stability of the relativistic plasma wave to drive it close to the wavebreaking.

Osteoclastic cortical erosion as a determinant of subperiosteal osteoblastic bone formation in the femoral neck's response to BMU imbalance. Effects of stance-related loading and hip fracture

Femoral neck fractures have previously been shown to be associated with increased cortical and endocortical remodeling, reduced wall thickness of endocortical packets and cortical porosity. Femoral neck width is associated positively with history of lifetime physical activity; so we hypothesized that exposure to mechanical loading may influence the subperiosteal osteoblastic response to the weakening effect of intracortical bone resorption. In 21 femoral neck biopsies from female subjects (13 with hip fracture), there was a positive association between osteoblastic periosteal alkaline phosphatase expression shown in frozen sections and the percentage of cortical canals internal to the subperiosteal surface showing evidence of osteoclastic erosion (Goldner's stain; p =0.03). This was stronger in the plane of locomotor loading and particularly strong in the inferior (compression) cortex ( p =0.002). In 35 cases and 23 age/gender-matched postmortem controls, osteoid-bearing cortical canals (%) were significantly elevated in the fracture cases compared with the controls within the anterior region. There was also a significant correlation between cortical and endocortical %OS/BS (percentage osteoid surface to bone surface) (fracture, n =12; control, n =12) over the whole biopsy ( p =0.041). Generally, these associations of intracortical with endocortical remodeling were consistent with both envelopes being regulated by common processes. These results support the concept that the slow growth of femoral neck width by subperiosteal apposition of bone occurs directly or, otherwise, in response to the weakening of the cortex as it is "trabecularized" by imbalance of bone multicellular units (BMU). This process, in turn, depends on cortical thinning and enlargement of canals with the formation of giant, composite osteons, the whole being more marked in cases of future hip fracture.

Bone mineralization density and femoral neck fragility

The traditional view of osteoporotic fractures is that they result from a reduction in bone mass combined with alterations in the micro-architecture. Apart from the effects of bone remodeling, the material properties of the remaining bone are thought to be unaffected. To test this, we compared the degree of matrix mineralization in femoral neck biopsies taken from cases of intracapsular hip fracture with age- and sex-matched postmortem controls. Whole femoral neck biopsies from seven female hip fracture cases (72-90 years) and nine controls (68-94 years) were embedded in methylmethacrylate, and sections stained with Solochrome Cyanin R for analysis of osteoid. The blocks were then diamond micro-milled, carbon coated, and analyzed for the degree of matrix mineralization using halogenated dimethacrylate standards for quantitative backscattered electron (qBSE) imaging (20 kV, entire block face, sampling interval 5 microm). The BSE gray scale was adjusted such that 0 corresponds to an electron backscattering coefficient of 0.1159 (approximately 1.70 g/ml) and 255-0.1519 (approximately 2.18 g/ml). Remodeling and mineralization data were analyzed for both the whole biopsy face and on a regional (anterior; inferior, posterior, or superior) basis. Over the whole biopsy, the level of mineralization was lower in the cases than the postmortem controls (-2.8%, P < 0.05). In both cases and controls, cortical mineralization was higher in the inferior (compressive) region compared with superior (tensile) region (P < 0.05). Mineralization was lower in all regions of the cases (inferior: -3.3%; posterior: -3.1%; anterior: -2.7%; superior: -1.6%) compared to the controls. Mineralization density in cancellous bone was not regionally dependent but was lower in the fracture cases (-3.5%; P = 0.001). Although there were weak relationships between osteoid formation (%O.Ar/B.Ar) and the mean level of mineralization in both cortical (P = 0.068) and cancellous (P < 0.01) bone, adjustment for this did not markedly affect the case-control differences. In conclusion, this study has shown that in cases of intracapsular hip fracture, matrix mineralization is reduced in the femoral neck. Unexpectedly, in view of the likely role of mild to moderate vitamin D deficiency osteopathy in hip fracture, this decreased mineralization was independent of osteoid indices and therefore potentially independent of bone age. This raises the possibility that alterations in the bone matrix such as excessive glycation or changes in the composition of the collagen fibrils affect its mineralization in hip fracture cases.

Discrimination between cases of hip fracture and controls is improved by hip structural analysis compared to areal bone mineral density. An ex vivo study of the femoral neck

In vivo bone densitometry is affected by measurement inaccuracies arising from the assumptions made about soft tissue and marrow composition. This study tested the hypothesis that section modulus (SM, a measure of bending resistance) when measured ex vivo, would discriminate cases of hip fracture from controls better than areal bone mineral density (aBMD). The biopsies were from (n = 22, female) subjects that had suffered an intracapsular hip fracture. The control material (n = 24, female) was from post-mortem subjects. Serial peripheral quantitative computed tomography (pQCT) 1-mm thick cross-sectional images of femoral neck previously embedded in methacrylate were obtained with the Densiscan 1000 pQCT densitometer and matched for lateral location. The image voxels were converted to units of bone mass, which were then used to derive the section modulus. The data were used to derive means from which receiver operating characteristic (ROC) curves could be generated. The area under the curves (AUC) showed that discrimination between the fracture cases and controls was better for SM than aBMD [SM: AUC = 0.83 (95% confidence interval: 0.71, 0.96), aBMD: AUC = 0.70 (0.54, 0.85); P = 0.034]. To simulate the forces experienced during a sideways fall, the model's neutral axis was rotated by 210 degrees. The results for section modulus were predictable from those at 0 degrees (r(2) = 0.97). We conclude that biomechanical analysis of the distribution of bone within the femoral neck may offer a marked improvement in the ability to discriminate patients with an increased risk of intracapsular fracture. Progress towards implementing this form of analysis in clinical densitometry should improve its diagnostic value, but may depend in part on better image resolution and more accurate corrections for the variability between subjects in regional soft tissue composition.

Bone remodeling at the endocortical surface of the human femoral neck: a mechanism for regional cortical thinning in cases of hip fracture

Endocortical remodeling and wall thickness (W.Th.) were measured in femoral neck bone from 12 female fracture cases (81.3 +/- 1.5 years) and 12 sex-matched controls (81.9 +/- 1.9 years). Regionally, osteoid and eroded surface were increased, whereas W.Th. was reduced. These processes likely contribute to cortical bone loss seen in hip fracture.

INTRODUCTION

Because periosteal expression of alkaline phosphatase was similar between cases and controls, we hypothesized that the mechanism causing the marked femoral neck cortical thinning associated with hip fracture may be net endocortical bone loss.

METHODS

Twelve female cases of femoral neck fracture (mean age = 81.3 +/- 1.5 years) and 12 age- and sex-matched postmortem controls (mean age = 81.9 +/- 1.9 years) were included in the study. Samples of their femoral neck bone were embedded in methyl methacrylate, sectioned at 10 microm, and stained with Solochrome cyanine R and Goldner's trichrome for the detection of osteoid (%OS/BS) and resorption surfaces (%ES/BS) respectively. In addition, wall thickness (W.Th.) and lamellar thickness (Lm.Th.) data were also collected from identifiable endocortical bone packets as a measure of formative potential.

RESULTS AND CONCLUSIONS

%OS/BS was significantly elevated in the anterior (control = 3.4 +/- 0.7: fracture = 11.0 +/- 2.3; p = 0.0001), inferior (3.4 +/- 1.0: 9.9 +/- 3.0; p = 0.0009), and posterior quadrants (3.2 +/- 0.8: 9.1 +/- 2.3; p = 0.0021). Only for anterior region was increased %ES/BS demonstrated in the fracture group (2.8 +/- 0.6: 5.3 +/- 0.7; p = 0.055). W.Th. (mm) was reduced only in the inferior region of the fracture cases (control = 33.7 +/- 1.2: fracture = 30.6 +/- 0.9; p = 0.013), whereas Lm.Th. was also reduced inferiorly (control = 2.7 +/- 0.08: fracture = 2.5 +/- 0.08; p = 0.042). These data suggest that an endocortical remodeling imbalance involving reduced bone formation within inferior region coupled with elevated anterior resorption may make an important contribution to the cortical thinning observed in cases of femoral neck fracture.

The amygdaloid complex: anatomy and physiology

A converging body of literature over the last 50 years has implicated the amygdala in assigning emotional significance or value to sensory information. In particular, the amygdala has been shown to be an essential component of the circuitry underlying fear-related responses. Disorders in the processing of fear-related information are likely to be the underlying cause of some anxiety disorders in humans such as posttraumatic stress. The amygdaloid complex is a group of more than 10 nuclei that are located in the midtemporal lobe. These nuclei can be distinguished both on cytoarchitectonic and connectional grounds. Anatomical tract tracing studies have shown that these nuclei have extensive intranuclear and internuclear connections. The afferent and efferent connections of the amygdala have also been mapped in detail, showing that the amygdaloid complex has extensive connections with cortical and subcortical regions. Analysis of fear conditioning in rats has suggested that long-term synaptic plasticity of inputs to the amygdala underlies the acquisition and perhaps storage of the fear memory. In agreement with this proposal, synaptic plasticity has been demonstrated at synapses in the amygdala in both in vitro and in vivo studies. In this review, we examine the anatomical and physiological substrates proposed to underlie amygdala function.

Increased cancellous bone in the femoral neck of patients with coxarthrosis (hip osteoarthritis): a positive remodeling imbalance favoring bone formation

Osteoporosis is caused by an imbalance between bone resorption and formation which results in an absolute reduction in bone mass. In a previous study we highlighted a condition, osteoarthritis of the hip (coxarthrosis, cOA), where an imbalance between resorption and formation provided beneficial effects in the form of an absolute increase in bone mass. We demonstrated that the femoral neck in patients with cOA had increased cancellous bone area, connectivity and trabecular thickness which might contribute to the protection against fracture associated with the condition. The aim of the present study was to analyze forming and resorbing surfaces in coxarthritic cancellous bone to assess whether increased formation or reduced resorption could be responsible for these structural changes. Whole cross-sectional femoral neck biopsies were obtained from 11 patients with cOA and histomorphometric parameters compared with 14 age- and sex-matched cadaveric controls. The ratio of osteoid surface to bone surface was 121% ( p<0.001) higher in the cases but there was no significant difference in resorptive surface. The percentage osteoid volume to bone volume (%OV/BV; +270%, p<0.001) and osteoid width (O.Wi; +127%, p<0.001) were also higher in the cases. This study suggests that the increased cancellous bone mass seen in cases of cOA is due to increased bone formation rather than decreased bone resorption. Investigation of the cellular and biochemical basis for these changes might provide new insights into the pathogenesis of osteoarthritis and highlight novel biological mechanisms regulating bone multicellular unit (BMU) balance that could be relevant to developing new interventions against hip and other osteoporotic fractures.

Evidence for bone formation on the external "periosteal" surface of the femoral neck: a comparison of intracapsular hip fracture cases and controls

Age-related expansion of the external surface of the femoral neck in order to offset generalized bone loss is potentially an important mechanism whereby hip strength and hence resistance to hip fracture is maintained. However, it has been widely assumed that bone formation is precluded from this external interface due to the presence of a synovial membrane associated with the hip joint. In this study we have demonstrated histologically that bone formation does indeed occur on the outer "periosteal" surface of the proximal femoral neck. It was therefore hypothesized that an impairment or reduction in periosteal bone formation might be seen in cases of femoral neck fracture compared with age-matched controls. Qualitative analysis of whole femoral neck samples from female subjects and age- and sex-matched post-mortem controls demonstrated that these groups expressed similar distributions of the bone formation marker, alkaline phosphatase (AP), at the periosteal surface [whole biopsy mean % periosteal AP-positive surface: control=16.0 (range=0.5-43.0), fracture=13.4 (range=1.0-34.6), p=0.44]. In conclusion, despite a wide intersubject variation, bone formation at the femoral neck periosteum is a feature of elderly women even if they have had a hip fracture.

The ratio of osteocytic incorporation to bone matrix formation in femoral neck cancellous bone: an enhanced osteoblast work rate in the vicinity of hip osteoarthritis

Recently it has been shown that an inactivating mutation in the TGFb-SMAD3 signaling pathway, which increases the conversion of osteoblasts to osteocytes, is accompanied by bone loss combined with increased osteocyte density. We hypothesized that increased matrix TGFb, known to occur in osteoarthritis, might cause the reverse of these effects in man. Because coxarthrosis (cOA) is associated with a reduced risk of femoral neck fracture, whole cross-section femoral neck biopsies were obtained from 11 patients with femoral neck fracture, 14 patients with cOA, and 22 age-and sex-matched controls. Lacunar density (Lc x mm2), osteocyte density (Ot x mm2), and cancellous wall width (Cn x W x Wi), were compared between cases of coxarthrosis, femoral neck fracture (FNF) and controls. In cOA, Lc.mm2 was reduced by 24% (P <0.001) while in FNF it was increased by 20% (P <0.001). Cn x W x Wi was increased in cOA by 22% (P <0.05) and in FNF was reduced by 27% (P <0.001). Lc x mm2 was inversely related to percentage cancellous bone area (adj. r2 = 0.373; P <0.01) and wall widths, r2 = 0.382, P <0.001. The reduction in osteocyte lacunar density coupled with increased wall width is consistent with a model of cOA effects on bone in which increased levels of matrix TGFb might prolong the effective lifespan or work rate of the osteoblast and delay its incorporation into the matrix as an osteocyte. One possible approach to strengthening bone in osteoporosis might be to enhance the effective lifespan of the osteoblast by modulating TGFb-related pathway activity in its local environment.

Increased femoral neck cancellous bone and connectivity in coxarthrosis (hip osteoarthritis)

Patients with coxarthrosis (cOA) have a reduced incidence of intracapsular femoral neck fracture, suggesting that cOA offers protection. The distribution of bone in the femoral neck was compared in cases of coxarthrosis and postmortem controls to assess the possibility that disease-associated changes might contribute to reduced fragility. Whole cross-section femoral neck biopsies were obtained from 17 patients with cOA and 22 age- and sex-matched cadaveric controls. Densitometry was performed using peripheral quantitated computed tomography (pQCT) and histomorphometry on 10-microm plastic-embedded sections. Cortical bone mass was not different between cases and controls (P > 0.23), but cancellous bone mass was increased by 75% in cOA (P = 0.014) and histomorphometric cancellous bone area by 71% (P < 0.0001). This was principally the result of an increase of apparent density (mass/vol) of cancellous bone (+45%, P = 0.001). Whereas cortical porosity was increased in the cases (P < 0.0001), trabecular width was also increased overall in the cases by 52% (P < 0.001), as was cancellous connectivity measured by strut analysis (P < 0.01). Where osteophytic bone was present (n = 9) there was a positive relationship between the amount of osteophyte and the percentage of cancellous area (P < 0.05). Since cancellous bone buttresses and stiffens the cortex so reducing the risk of buckling, the increased cancellous bone mass and connectivity seen in cases of cOA probably explain, at least in part, the ability of patients with cOA to resist intracapsular fracture of the femoral neck during a fall.

Osteocyte density in aging subjects is enhanced in bone adjacent to remodeling haversian systems

The osteocyte is a candidate regulatory cell for bone remodeling. Previously, we demonstrated that there is a substantial (approximately 50%) loss of osteocytes from their lacunae in the cortex of the elderly femoral neck. Higher occupancy was evident in tissue exhibiting high remodeling and high porosity. The present study examines the distribution of osteocytes within individual osteonal systems at differing stages of the remodeling cycle. In 22 subjects, lacunar density, osteocyte density, and their quotient, the percent lacunar occupancy, was assessed up to a distance of 65 microm from the canal surface in six quiescent, resorbing, and forming osteons. In both forming (p = 0.024) and resorbing (p = 0.034) osteons, osteocyte densities were significantly higher in cases of hip fracture than controls. However, there were no significant between-group differences in lacunar occupancy. In both cases and controls, osteocyte density (p < 0.0001; mean difference +/-SEM: 157 +/- 34/mm2) and lacunar occupancy (p = 0.025; mean difference: 8.1 +/- 3.4%) were shown to be significantly higher in forming compared with quiescent osteons. Interestingly, resorbing systems also exhibited significantly elevated osteocyte density in both the fracture and the control group combined (mean difference 76 +/- 23/mm2; p = 0.003). Lacunar occupancy was also greater in resorbing compared with quiescent osteons (both groups combined: p = 0.022; mean difference: 5.7 +/- 2.3%). Elevated osteocyte density and lacunar occupancy in forming compared with quiescent systems was expected because of the likely effects of aging on quiescent osteons. However, the higher levels of these parameters in resorbing compared with quiescent systems was the opposite of what we expected and suggests that, in addition to their postulated mechanosensory role in the suppression of remodeling and bone loss, osteocytes might also contribute to processes initiating or maintaining bone resorption.

Patterns of osteocytic endothelial nitric oxide synthase expression in the femoral neck cortex: differences between cases of intracapsular hip fracture and controls

Evidence indicates that extensive amalgamation of adjacent resorbing osteons is responsible for destroying the microstructural integrity of the femoral neck's inferior cortex in osteoporotic hip fracture. Such osteonal amalgamation is likely to involve a failure to limit excessive resorption, but its mechanistic basis remains enigmatic. Nitric oxide (NO) inhibits osteoclastic bone destruction, and in normal bone cells its generation by endothelial nitric oxide synthase (eNOS, the predominant bone isoform) is enhanced by mechanical stimuli and estrogen, which both protect against fracture. To determine whether eNOS expression in osteocytes reflects their proposed role in regulating remodeling, we have examined patterns of osteocyte eNOS immunolabeling in the femoral neck cortex of seven cases of hip fracture and seven controls (females aged 68-96 years). The density of eNOS+ cells (mm(-2)) was 53% lower in the inferior cortex of the fracture cases (p < 0.0004), but was similar in the superior cortex. eNOS+ osteocytes were, on average, 22% further from their nearest blood supply, than osteocytes in general (p < 0.0001) and the nearest eNOS+ osteocyte was 57% further from its nearest canal surface (p < 0.0001). This differential distribution of eNOS+ osteocytes was significantly more pronounced in the cortices of fracture cases (p < 0.0001). We conclude that the normal regional and osteonal pattern of eNOS expression by osteocytes is disrupted in hip fracture, particularly at sites that are loaded most by physical activity. These results suggest that eNOS+ osteocytes may normally act as sentinels confining resorption within single osteons. A reduction in their number, coupled to an increase in their remoteness from canal surfaces, may thus permit the irreversible merging of resorbing osteons, and thus contribute to the marked increase in the fragility of osteoporotic bone.

Intracapsular hip fracture and the region-specific loss of cortical bone: analysis by peripheral quantitative computed tomography

Generalized bone loss within the femoral neck accounts for only 15% of the increase in intracapsular hip fracture risk between the ages of 60 and 80 years. Conventional histology has shown that there is no difference in cancellous bone area between cases of intracapsular fracture and age and sex-matched controls. Rather, a loss of cortical bone thickness and increased porosity is the key feature with the greatest change occurring in those regions maximally loaded during a fall (the inferoanterior [IA] to superoposterior [SP] axis). We have now reexamined this finding using peripheral quantitative computed tomography (pQCT) to analyze cortical and cancellous bone areas, density, and mass in a different set of ex vivo biopsy specimens from cases of intracapsular hip fracture (female, n = 16, aged 69-92 years) and postmortem specimens (female, n = 15, aged 58-95 years; male, n = 11, aged 56-86 years). Within-neck location was standardized by using locations at which the ratio of maximum to minimum external diameters was 1.4 and at more proximal locations. Cortical widths were analyzed using 72 radial profiles from the center of area of each of the gray level images using a full-width/half-maximum algorithm. In both male and female controls, cancellous bone mass increased toward the femoral head and the rate of change was gender independent. Cancellous bone mass was similar in cases and controls at all locations. Overall, cortical bone mass was significantly lower in the fracture cases (by 25%; p < 0.001) because of significant reductions in both estimated cortical area and density. These differences persisted at locations that are more proximal. The mean cortical width in the cases was significantly lower in the IA (22.2%;p = 0.002) and inferior regions (19%;p < 0.001). The SP region was the thinnest in both cases and controls. These data confirm that a key feature in the etiology of intracapsular hip fracture is the site-specific loss of cortical bone, which is concentrated in those regions maximally loaded during a fall on the greater trochanter. An important implication of this work is that the pathogenesis of bone loss leading to hip fracture must be by a mechanism that varies in its effect according to location within the femoral neck Key candidate mechanisms would include those involving locally reduced mechanical loading. This study also suggests that the development of noninvasive methodologies for analyzing the thickness and estimated densities of critical cortical regions of the femoral neck could improve detection of those at risk of hip fracture.

Osteocyte lacunar occupancy in the femoral neck cortex: an association with cortical remodeling in hip fracture cases and controls

In adult humans, osteocytes die and disappear from their lacunae in the cortex of bones which remodel slowly, such as the proximal femur, and osteocyte death is particularly prevalent in the elderly. We have investigated the statistical determinants of osteocyte density in microscopic fields (0.71 mm2) within thin, complete femoral neck cross-sections cut from biopsies embedded in methyl methacrylate and stained with solochrome cyanine R. Lacunae were counted under phase contrast and osteocytes within lacunae were counted in the same fields under epifluorescence. The percentage of lacunae containing an osteocyte varied between 12.4% and 99.2%, according to subject and quadrantic region of the cortex examined. The microscopic determinants of field-specific osteocyte density included the porosity measured in the field itself and the regional measurement of the proportion of cortical canals bearing osteoid. There was significant variation between subjects and, within subjects, between cortical regions. Also the inferior region showed a significantly higher density of lacunae than the superior region (+8.2%; P = 0.013). However, cases of fracture were not significantly different from controls with respect to osteocyte lacunar occupancy after adjusting for osteoid-bearing canals and porosity. It is concluded that in subjects in their 7th-9th decades of age, osteocyte lacunar occupancy is statistically associated with bone turnover, implying that high turnover (locally young bone age) might favor lacunar occupancy (ln% osteoid; P = 0.021). Alternative explanations of the association are that porosity reflects a better nutritional supply via the vasculature or that porosity of the cortex is associated with osteocyte density through an effect of osteocytes on bone remodeling.

Phased-Array intracardiac echocardiography to guide radiofrequency ablation in the left atrium and at the pulmonary vein ostium

INTRODUCTION

We sought to evaluate the utility of a phased-array intracardiac echocardiography (ICE) device to identify left atrial (LA) and pulmonary vein (PV) anatomy; accurately guide radiofrequency ablation (RFA) to the right or left PV ostium and LA appendage (LAA); and evaluate PV blood flow before and after RFA using Doppler parameters.

METHODS AND RESULTS

Twelve adult sheep were anesthetized and an Acuson 10-French, 7-MHz ICE transducer introduced via the internal jugular vein into the right atrium. The LA was imaged and PV anatomy and blood flow documented using two-dimensional and pulsed-wave Doppler. Mean LA dimensions were 4.6 +/- 0.4 x 3.5 +/- 0.5 cm; mean single right and left main PV ostium diameters were 1.5 +/- 0.2 and 1.3 +/- 0.3 cm; and mean right and left PV first-order branch diameters were 0.8 +/-0.2 and 0.6 +/- 0.1 cm. Mean PV maximum inflow velocity for the right PV were 0.30 +/- 0.05 m/sec and for the left PV were 0.35 +/- 0.04 m/sec. The PV ostia and LAA could be targeted accurately for RFA using ICE guidance. At pathologic evaluation, the mean distance of the lesion center to the right or left PV-LA junction was 3.0 +/- 2.0 mm. The mean distance of the lesion center to the posterior margin of the LAA was <4 mm in all cases. There was no significant increase in PV maximum inflow velocity or decrease in PV diameter following RFA at the PV ostium. Absence of PV obstruction was confirmed at pathology.

CONCLUSION

Phased-array ICE allows detailed assessment of LA and PV anatomy when imaged from the right atrium; accurate guidance of RFA to the PV ostium and LAA; and immediate evaluation of PV patency after RFA.

Clinical and angiographic outcome in the laser angioplasty for restenotic stents (LARS) multicenter registry

In-stent restenosis (ISR), when treated with balloon angioplasty (PTCA) alone, has an angiographic recurrence rate of 30%-85%. Ablating the hypertrophic neointimal tissue prior to PTCA is an attractive alternative, yet the late outcomes of such treatment have not been fully determined. This multicenter case control study assessed the angiographic and clinical outcomes of 157 consecutive procedures in 146 patients with ISR at nine institutions treated with either PTCA alone (n = 64) or excimer laser assisted coronary angioplasty (ELCA, n = 93)) for ISR. Demographics were similar except more unstable angina at presentation in ELCA-treated patients (74.5% vs. 63.5%; P = 0.141). Lesions selected for ELCA were longer (16.8 +/- 11.2 mm vs. 11.2 +/- 8.6 mm; P < 0.001), more complex (ACC/AHA type C: 35.1% vs. 13.6%; P < 0.001), and with compromised antegrade flow (TIMI flow < 3: 18.9% vs. 4.5%; P = 0.008) compared to PTCA-treated patients. ELCA-treated patients had similar rate of procedural success [93 (98.9% vs. 62 (98.4%); P = 1.0] and major clinical complications [1 (1.1%) vs. 1 (1.6%); P = 1.0]. At 30 days, repeat target site coronary intervention was lower in ELCA-treated patients (1.1% vs. 6.4% in PTCA-treated patients; P = 0.158), but not significantly so. At 1 year, ELCA-treated patients had similar rate of major cardiac events (39.1% vs. 45.2%; P = 0.456) and target lesion revascularization (30.0% vs. 32.3%; P = 0.646). These data suggest that ELCA in patients with complex in-stent restenosis is as safe and effective as balloon angioplasty alone. Despite higher lesion complexity in ELCA-treated patients, no increase in event rates was observed. Future studies should evaluate the relative benefit of ELCA over PTCA alone for the prevention of symptom recurrence specifically in patients with complex in-stent restenosis.

Laparoscopic lymphocele drainage after renal transplantation

The formation of a lymphocele in small pelvis following renal transplantation is a well-known complication. Although various non-operative methods are available, laparotomy with transperitoneal internal drainage has been the gold standard for the treatment of lymphoceles. In 1991, internal drainage of a renal transplant lymphocele was performed for the first time laparoscopically. Nine patients with symptomatic lymphoceles were treated using laparoscopic technique, between July 1995 and November 1999 in the Surgical Department of the District Hospital in Szczecin. In 8 patients, the laparoscopic approach was successful and no further therapy was required. In one case, the videoscopic procedure had to be converted to open surgery. Operative time ranged from 15 to 60 minutes. The postoperative course was uneventful in all nine cases. Laparoscopic method of treatment of a renal transplant lymphocele combines the efficiency of internal surgical drainage, with the minimal invasiveness of non-operative techniques. It reduces postoperative pain, shortens length of hospitalisation and convalescence, and has a similar recurrence rate to open surgery.

A second outbreak of hepatitis C virus infection from anti-D immunoglobulin in Ireland

OBJECTIVE

To investigate the infectivity for hepatitis C virus (HCV) of intravenous anti-D immunoglobulin batches manufactured in Ireland between 1991 and 1994.

METHODS

Women who had received anti-D manufactured between 1991 and 1994 were screened for serological markers of HCV infection and for the presence of HCV RNA by RT-PCR amplification and virus genotyping.

RESULTS

44 women exposed to anti-D manufactured between 1991 and 1994 were polymerase chain reaction positive for HCV RNA, 19 of whom were infected with genotype 3a virus shown by phylogenetic analysis of the NS5B gene to be closely related to that from the single implicated donor.

CONCLUSIONS

Anti-D manufactured in 1991-1994 transmitted infection of HCV genotype 3a. The prevalence of HCV-specific antibody in anti-D recipients was relatively low (0.59%), consistent with the low level of virus RNA in these anti-D batches.

Transmission rates of hepatitis C virus by different batches of a contaminated anti-D immunoglobulin preparation

BACKGROUND AND OBJECTIVES

The aim of this study was to determine the hepatitis C virus (HCV) infection rate of recipients of different batches of anti-D immunoglobulin associated with an outbreak of HCV infection which occurred in 1977 and its relationship to the polymerase chain reaction (PCR) status of the implicated batches. This study was undertaken to determine the predictive value of HCV genome detection and quantification for subsequent infection in recipients of an HCV-contaminated anti-D immunoglobulin product for intravenous use.

MATERIALS AND METHODS

Sera from recipients of anti-D were tested by HCV enzyme immunoassay and if found positive were subsequently tested by recombinant immunoblot assay and HCV PCR in a national HCV anti-D screening programme set up in 1994. The HCV status of 1,342 known recipients of infectious or potentially infectious batches has been compared to the amount of HCV RNA in the anti-D batch they received so as to determine the value of PCR in the prediction of infectivity in immunoglobulin preparations.

RESULTS

It has been demonstrated that HCV-infected plasma derived from batches of anti-D showing levels of viral genome in excess of 10(4) genomes per millilitre led to infection of up to 60% of recipients. In contrast, batches with undetectable levels of HCV genome very rarely transmitted infection.

CONCLUSIONS

The presence of HCV RNA in intravenous immunoglobulin preparations which have not undergone a specific viral inactivation step is a predictor of HCV infection in recipients.

A novel mechanism for induction of increased cortical porosity in cases of intracapsular hip fracture

It has been suggested that, in hip fracture, the cortex on the inferoanterior (IA) to superoposterior (SP) axis is thinned and shows increased porosity. This is dependent on the presence of giant canals (i.e., diameter >385 microm), which are related to clusters of remodeling osteons. To investigate further the relationship between remodeling and bone loss, osteonal diameter (On.Dm), wall thickness (W.Th), osteoid width (O.Wi), and extent (OS) were measured in femoral neck biopsies from 12 female intracapsular hip fracture cases and 11 age- and gender-matched controls. Over 83% of giant canals were "composite" osteonal systems in which a single canal was surrounded by multiple packets of osteonal bone. Among smaller canals, over 80% of systems had a canal encircled by a single cement line containing one packet of bone ("simple"). Composites were nearly twice as prevalent in fractures (fracture cases 9.8 +/- 0.7/25 mm(2), controls 5.3 +/- 0.4/25 mm(2), p < 0. 0001), and were dependent (R(2) = 0.52) on femoral neck region (p = 0.0008) and the regional distribution of clusters of remodeling osteons (p = 0.0045). Both the inferior (I) and anterior (A) regions had an elevated number of composites (I: 263% of control values, p = 0.0054; A: 202% of control values, p = 0.0092). On.Dm was similar in fracture cases and controls (simple: fracture cases 183 +/- 3 microm, controls 191 +/- 4 microm; composites: fracture cases 446 +/- 13 microm, controls 460 +/- 13 microm). W.Th in simples was similar in fracture cases and controls (fracture cases 51 +/- 0.8 microm, controls 49 +/- 0.7 microm), but composites had significantly (p < 0. 0001) thinner walls, with the reduction in fracture cases (31%) being twice that of controls (12%, p < 0.0001). There were no differences in O.Wi. It was unusual for osteoid to fully surround the composite canal surface; OS was 38% lower in composite than simple canals (p < 0.0001). This study indicates that, in the femoral neck cortex, the principal remodeling deficit in hip fracture is specific to composite osteons. Hip fracture cases had zonal increases in composite osteon density with reduced bone formation. The data suggest that generation of composite osteons is a plausible mechanism leading to increasing porosity and trabecularization of the cortex, thus weakening the cortex in regions maximally loaded on fall impact.

Microtubule-associated protein 1B is a component of cortical Lewy bodies and binds alpha-synuclein filaments

Lewy bodies, neuropathological hallmarks of Parkinson's disease and dementia with Lewy bodies, comprise alpha-synuclein filaments and other less defined proteins. Characterization of Lewy body proteins that interact with alpha-synuclein may provide insight into the mechanism of Lewy body formation. Double immunofluorescence labeling and confocal microscopy revealed approximately 80% of cortical Lewy bodies contained microtubule-associated protein 1B (MAP-1B) that overlapped with alpha-synuclein. Lewy bodies were isolated using an immunomagnetic technique from brain tissue of patients dying with dementia with Lewy bodies. Lewy body proteins were resolved by polyacrylamide gel electrophoresis. Immunoblotting confirmed the presence of MAP-1B and alpha-synuclein in purified Lewy bodies. Direct binding studies revealed a high affinity interaction (IC(50) approximately 20 nm) between MAP-1B and alpha-synuclein. The MAP-1B-binding sites were mapped to the last 45 amino acids of the alpha-synuclein C terminus. MAP-1B also bound in vitro assembled alpha-synuclein fibrils. Thus, MAP-1B may be involved in the pathogenesis of Lewy bodies via its interaction with monomeric and fibrillar alpha-synuclein.

Children's needs in shelters: mother's perceptions

The needs of children who witness violence directed at their mothers have only recently gained attention. While shelter services to address children's responses are increasingly evident, there is still much we do not understand about their plight, particularly from the perspective of their mothers. This study used focus-group methodology to identify mothers' perceptions of their children's needs while they were in shelters. Five focus group sessions were held with 27 mothers who had experienced violence in their homes and had used shelter services within the previous two-year period. Data were analyzed to identify six dominant categories of need and 12 supporting thematic categories. The dominant categories included: the counselling needs of the children; day-to-day living needs, such as maintaining family integrity and normality; recreational needs; the needs of children with respect to parenting; and finally, aspects of shelter support for mothers, and the impact of the shelter environment on children. The implications of the findings for program development are discussed.