bluuebunny/crossref_metadata_2025 huggingface dataset:
always Othered
Authors: Lahman Maria K.E.
Published: September 2008

The author takes the stance that children are always Othered or unfamiliar in research. The child as Other is intensified by adults' memories of their own childhoods. The author discusses what it means to be Othered, reviews images of children, and the roles early childhood research methodologists recommend a researcher should hold. Through narratives the author interrupts the text and reflects on her own childhood, research and teaching young children. Finally, methodological recommendations for utilizing or minimizing the researcher/child Othered relationship are set forth in the following areas: ethical consideration, reflexivity, intersubjectivity, innovative methods, children are experts, and being with children.
Early Results for Below-Knee Bypasses Using Distaflo
Authors: Gulkarov Iosif , Malik Rajesh , Yakubov Rakhsim , Gagne Paul , Muhs Bart E. , Rockman Caron , Cayne Neal S. , Jacobowitz Glenn R. , Lamparello Patrick J. , Adelman Mark A. , Maldonado Thomas S.
Published: September 2008

In patients who require lower extremity revascularization, prosthetic graft is a reasonable alternative in the absence of a suitable autologous vein conduit. However, prosthetic bypass grafts have limited patency, especially for infrageniculate reconstruction. Polytetrafluoroethylene grafts were geometrically modified at the distal end to increase their patency. The authors reviewed their experience with the Distaflo graft in patients who required lower extremity below-knee popliteal and tibial bypasses when no suitable autologous vein conduit was available. Chart review was conducted of the 57 patients who underwent 60 lower extremity bypasses over a 3-year period between June 2003 and April 2006. Twenty-four revascularizations were constructed to the tibial outflow sites, whereas the remaining grafts were placed to the below-knee (28) and above-knee (8) popliteal artery, respectively. Study endpoints were primary, assisted primary, secondary patency, and limb salvage at the time of follow-up. Distaflo bypass was performed at the infrageniculate level in 86.7% of cases (28 below-knee popliteal, 24 tibial). Mean follow-up time was 12 months (range, 0.5-37.5 months). At 1 year, primary, assisted primary, and secondary patencies and limb salvage rates for below-knee popliteal bypasses were 83.5%, 89.5%, 94.7%, and 94.4%, respectively. Primary, assisted primary, and secondary patencies and limb salvage rates for tibial bypasses were 44.4%, 44.4%, 63.2%, and 74.9%, respectively. Distaflo precuffed graft is a good alternative conduit for below-knee popliteal and tibial lower extremity reconstructions in the absence of an autologous vein and appears to have promising early patency and limb salvage rates even when used for tibial bypasses.
Electrodermal Recording and fMRI to Inform Sensorimotor Recovery in Stroke Patients
Authors: MacIntosh Bradley J. , McIlroy William E. , Mraz Richard , Staines W. Richard , Black Sandra E. , Graham Simon J.
Published: September 2008

Background. Functional magnetic resonance imaging (fMRI) appears to be useful for investigating motor recovery after stroke. Some of the potential confounders of brain activation studies, however, could be mitigated through complementary physiological monitoring. Objective. To investigate a sensorimotor fMRI battery that included simultaneous measurement of electrodermal activity in subjects with hemiparetic stroke to provide a measure related to the sense of effort during motor performance. Methods. Bilateral hand and ankle tasks were performed by 6 patients with stroke (2 subacute, 4 chronic) during imaging with blood oxygen level-dependent (BOLD) fMRI using an event-related design. BOLD percent changes, peak activation, and laterality index values were calculated in the sensorimotor cortex. Electrodermal recordings were made concurrently and used as a regressor. Results. Sensorimotor BOLD time series and percent change values provided evidence of an intact motor network in each of these well-recovered patients. During tasks involving the hemiparetic limb, electrodermal activity changes were variable in amplitude, and electrodermal activity time-series data showed significant correlations with fMRI in 3 of 6 patients. No such correlations were observed for control tasks involving the unaffected lower limb. Conclusions. Electrodermal activity activation maps implicated the contralesional over the ipsilesional hemisphere, supporting the notion that stroke patients may require higher order motor processing to perform simple tasks. Electrodermal activity recordings may be useful as a physiological marker of differences in effort required during movements of a subject's hemiparetic compared with the unaffected limb during fMRI studies.
Historical Perspectives in Library and Information Science Research in the Nordic and Baltic Countries
Authors: Reimo Tiiu
Published: September 2008

This article aims to introduce research on book and library history in the Nordic and Baltic countries during the last ten to fifteen years. The role of historical subjects in library and information science (LIS) curricula has diminished in all curricula in Europe. As a result, a threat to the continuity of academic research can be observed. The books and articles on book and library history published in the Nordic and Baltic countries are difficult to access for the international community of researchers, as a majority of them have been published only in local languages. This article presents the main achievements in the history of the book, printing, publishing and the book trade, and library history. The publications presented in the article reflect the personal choice of the author. In 2006 Nordic and Baltic researchers joined the scholarly network HIBOLIRE (History of Books, Libraries and Reading). The activities of the network are financed by the Nordforsk Foundation. The aim of the network is to enhance collaboration between individual researchers and their home institutions, as well as to intensify doctoral studies and contacts between doctoral students.
Reading the Bible, Preserving the Precious Text: Latvian Peasant Metal-Clad Bindings
Authors: Milevski Robert J , Villerušs Valdis
Published: September 2008

Religious books were an important part of a Latvian peasant's daily life during the mid- to late nineteenth century. From the physical evidence, these books were heavily used and became well worn. When originally bound, or following rebinding, the peasants applied metal furniture to the covers of the books as a practical measure to protect them from wear and tear. They infused the metal with designs and motifs familiar to them from everyday life. This adornment personifies the respect the peasants felt for their religious books — Bibles, hymnbooks and collections of sermons. As well, the designs mirror motifs as seen in folk arts, such as embroidery, jewellery, and furniture. Finally, the metal served a utilitarian purpose: to protect and preserve the book. These metal-clad bindings are known only in Latvia. They were produced in a particular part of the country and during a limited span of time, and are unique in bookbinding history.
From Légère Teinture to Central Place: A Revaluation of Book and Library History Within Library and Information Science Programmes
Authors: Delsaerdt Pierre
Published: September 2008

The author demonstrates that book and library history deserves a central place in library and information science programmes, but also that in order to obtain or keep this central place it needs to orient itself in a direction that is closer to the heart of what library and information science is about – the organization of knowledge and information-seeking behaviour. Book and library history can illustrate these processes and explain how they have developed in the past. Early phenomena of knowledge organization have to be studied in their broader contexts, and these contexts to a large extent cover the production, dissemination and consumption of books in the past. The main return that book history will get out of this process is that it will be more strongly integrated into academic teaching and research.
Ly49E-dependent inhibition of natural killer cells by urokinase plasminogen activator
Authors: Van Den Broeck Tina , Stevenaert Frederik , Taveirne Sylvie , Debacker Veronique , Vangestel Christel , Vandekerckhove Bart , Taghon Tom , Matthys Patrick , Plum Jean , Held Werner , Dewerchin Mieke , Yokoyama Wayne M. , Leclercq Georges
Published: September 2008

The Ly49 natural killer (NK)–cell receptor family comprises both activating and inhibitory members, which recognize major histocompatibility complex (MHC) class I or MHC class I–related molecules and are involved in target recognition. As previously shown, the Ly49E receptor fails to bind to a variety of soluble or cell-bound MHC class I molecules, indicating that its ligand is not an MHC class I molecule. Using BWZ.36 reporter cells, we demonstrate triggering of Ly49E by the completely distinct, non–MHC-related protein urokinase plasminogen activator (uPA). uPA is known to be secreted by a variety of cells, including epithelial and hematopoietic cells, and levels are up-regulated during tissue remodeling, infections, and tumorigenesis. Here we show that addition of uPA to Ly49E-positive adult and fetal NK cells inhibits interferon-γ secretion and reduces their cytotoxic potential, respectively. These uPA-mediated effects are Ly49E-dependent, as they are reversed by addition of anti-Ly49E monoclonal antibody and by down-regulation of Ly49E expression using RNA interference. Our results suggest that uPA, besides its established role in fibrinolysis, tissue remodeling, and tumor metastasis, could be involved in NK cell–mediated immune surveillance and tumor escape.
Kismeth: Analyzer of plant methylation states through bisulfite sequencing
Authors: Gruntman Eyal , Qi Yijun , Slotkin R Keith , Roeder Ted , Martienssen Robert A , Sachidanandam Ravi
Published: September 2008

Background

There is great interest in probing the temporal and spatial patterns of cytosine methylation states in genomes of a variety of organisms. It is hoped that this will shed light on the biological roles of DNA methylation in the epigenetic control of gene expression. Bisulfite sequencing refers to the treatment of isolated DNA with sodium bisulfite to convert unmethylated cytosine to uracil, with PCR converting the uracil to thymidine followed by sequencing of the resultant DNA to detect DNA methylation. For the study of DNA methylation, plants provide an excellent model system, since they can tolerate major changes in their DNA methylation patterns and have long been studied for the effects of DNA methylation on transposons and epimutations. However, in contrast to the situation in animals, there aren't many tools that analyze bisulfite data in plants, which can exhibit methylation of cytosines in a variety of sequence contexts (CG, CHG, and CHH).

Results

Kismeth http://katahdin.mssm.edu/kismeth is a web-based tool for bisulfite sequencing analysis. Kismeth was designed to be used with plants, since it considers potential cytosine methylation in any sequence context (CG, CHG, and CHH). It provides a tool for the design of bisulfite primers as well as several tools for the analysis of the bisulfite sequencing results. Kismeth is not limited to data from plants, as it can be used with data from any species.

Conclusion

Kismeth simplifies bisulfite sequencing analysis. It is the only publicly available tool for the design of bisulfite primers for plants, and one of the few tools for the analysis of methylation patterns in plants. It facilitates analysis at both global and local scales, demonstrated in the examples cited in the text, allowing dissection of the genetic pathways involved in DNA methylation. Kismeth can also be used to study methylation states in different tissues and disease cells compared to a reference sequence.
Genetic structure and breeding system in a social wasp and its social parasite
Authors: Hoffman Eric A , Kovacs Jennifer L , Goodisman Michael AD
Published: September 2008

Background

Social insects dominate ecological communities because of their sophisticated group behaviors. However, the intricate behaviors of social insects may be exploited by social parasites, which manipulate insect societies for their own benefit. Interactions between social parasites and their hosts lead to unusual coevolutionary dynamics that ultimately affect the breeding systems and population structures of both species. This study represents one of the first attempts to understand the population and colony genetic structure of a parasite and its host in a social wasp system.

Results

We used DNA microsatellite markers to investigate gene flow, genetic variation, and mating behavior of the facultative social parasite Vespula squamosa and its primary host, V. maculifrons. Our analyses of genetic variability uncovered that both species possessed similar amounts of genetic variation and failed to show genetic structure over the sampling area. Our analysis of mating system of V. maculifrons and V. squamosa revealed high levels of polyandry and no evidence for inbreeding in the two species. Moreover, we found no significant differences between estimates of worker relatedness in this study and a previous investigation conducted over two decades ago, suggesting that the selective pressures operating on queen mate number have remained constant. Finally, the distribution of queen mate number in both species deviated from simple expectations suggesting that mate number may be under stabilizing selection.

Conclusion

The general biology of V. squamosa has not changed substantially from that of a typical, nonparasitic Vespula wasp. For example, population sizes of the host and its parasite appear to be similar, in contrast to other social parasites, which often display lower population sizes than their hosts. In addition, parasitism has not caused the mating behavior of V. squamosa queens to deviate from the high levels of multiple mating that typify Vespula wasps. This stands in contrast to some socially parasitic ants, which revert to mating with few males. Overall, the general similarity of the genetic structure of V. maculifrons and V. squamosa presumably reflects the fact that V. squamosa is still capable of independent colony founding and thus reflects an intermediate stage in the evolution of social parasitism.
Characterization of attaching and effacing Escherichia coli (AEEC) isolated from pigs and sheep
Authors: Fröhlicher Erik , Krause Gladys , Zweifel Claudio , Beutin Lothar , Stephan Roger
Published: September 2008

Background

Attaching and effacing Escherichia coli (AEEC) are characterized by their ability to cause attaching-and-effacing (A/E) lesions in the gut mucosa of human and animal hosts leading to diarrhoea. The genetic determinants for the production of A/E lesions are located on the locus of enterocyte effacement (LEE), a pathogenicity island that also contains the genes encoding intimin (eae). This study reports data on the occurrence of eae positive E. coli carried by healthy pigs and sheep at the point of slaughter, and on serotypes, intimin variants, and further virulence factors of isolated AEEC strains.

Results

Faecal samples from 198 finished pigs and 279 sheep were examined at slaughter. The proportion of eae positive samples was 89% for pigs and 55% for sheep. By colony dot-blot hybridization, AEEC were isolated from 50 and 53 randomly selected porcine and ovine samples and further characterized. Strains of the serotypes O2:H40, O3:H8 and O26:H11 were found in both pigs and sheep. In pigs O2:H40, O2:H49, O108:H9, O145:H28 and in sheep O2:H40, O26:H11, O70:H40, O146:H21 were the most prevalent serotypes among typable strains. Eleven different intimin types were detected, whereas γ2/θ was the most frequent, followed by β1, ε and γ1. All but two ovine strains tested negative for the genes encoding Shiga toxins. All strains tested negative for the bfp A gene and the EAF plasmid. EAST1 (ast A) was present in 18 of the isolated strains.

Conclusion

Our data show that pigs and sheep are a source of serologically and genetically diverse intimin-harbouring E. coli strains. Most of the strains show characteristics of atypical enteropathogenic E. coli. Nevertheless, there are stx-negative AEEC strains belonging to serotypes and intimin types that are associated with classical enterohaemorrhagic E. coli strains (O26:H11, β1; O145:H28, γ1).
Worldwide food recall patterns over an eleven month period: A country perspective
Authors: Nepusz Tamás , Petróczi Andrea , Naughton Declan P
Published: September 2008

Background

Following the World Health Organization Forum in November 2007, the Beijing Declaration recognized the importance of food safety along with the rights of all individuals to a safe and adequate diet. The aim of this study is to retrospectively analyze the patterns in food alert and recall by countries to identify the principal hazard generators and gatekeepers of food safety in the eleven months leading up to the Declaration.

Methods

The food recall data set was collected by the Laboratory of the Government Chemist (LGC, UK) over the period from January to November 2007. Statistics were computed with the focus reporting patterns by the 117 countries. The complexity of the recorded interrelations was depicted as a network constructed from structural properties contained in the data. The analysed network properties included degrees, weighted degrees, modularity and k-core decomposition. Network analyses of the reports, based on 'country making report' (detector) and 'country reported on' (transgressor), revealed that the network is organized around a dominant core.

Results

Ten countries were reported for sixty per cent of all faulty products marketed, with the top 5 countries having received between 100 to 281 reports. Further analysis of the dominant core revealed that out of the top five transgressors three made no reports (in the order China > Turkey > Iran). The top ten detectors account for three quarters of reports with three > 300 (Italy: 406, Germany: 340, United Kingdom: 322).

Conclusion

Of the 117 countries studied, the vast majority of food reports are made by 10 countries, with EU countries predominating. The majority of the faulty foodstuffs originate in ten countries with four major producers making no reports. This pattern is very distant from that proposed by the Beijing Declaration which urges all countries to take responsibility for the provision of safe and adequate diets for their nationals.
Antihypertensive drug class and impaired fasting glucose: a risk association study among Chinese patients with uncomplicated hypertension
Authors: Wong Martin CS , Jiang Johnny Y , Fung H , Griffiths Sian , Mercer Stewart
Published: September 2008

Background

There is a scarcity of studies addressing the factors associated with impaired fasting glucose in Chinese patients with uncomplicated hypertension. We included 1,218 patients newly prescribed a single antihypertensive drug in the public primary healthcare setting in Hong Kong, where their fasting glucose levels were measured 6–7 weeks after the first-ever antihypertensive prescription.

Methods

The odds ratios of having above borderline (≥ 6.1 mmol/l) and adverse (≥ 7.0 mmol/l) glucose levels, respectively, were studied according to patient age, gender, socioeconomic status, clinic types and antihypertensive drug classes by multivariable regression analyses.

Results

The fasting glucose levels were statistically similar (p = 0.786) among patients prescribed thiazide diuretics (5.48 mmol/l, 95%, 5.38, 5.59), calcium channel blockers (5.46 mmol/l, 95% C.I. 5.37, 5.54), β-blockers (5.42 mmol/l, 95% C.I. 5.34, 5.51) and drugs acting on the renin angiotensin system (RAS) [5.41 mmol/l, 95% C.I. 5.20, 5.61]. Multivariate analyses reported no significant associations between antihypertensive drug class and impaired fasting glucose. Elderly patients and male gender were significantly more likely to present with above borderline and adverse readings respectively.

Conclusion

Clinicians should be aware of the increased risk of impaired fasting glucose in these groups, and use of thiazides should not in itself deter its use as a first-line antihypertensive agent among ethnic Chinese patients.
Sevoflurane requirement during elective ankle day surgery: the effects of etirocoxib premedication, a prospective randomised study
Authors: Turan Ibrahim , Hein Anette , Jacobson Eva , Jakobsson Jan G
Published: September 2008

Background

Anti-inflammatory drugs, NSAIDs, have become an important part of the pain management in day surgery. The aim of the present study was to evaluate the effect of Coxib premedication on the intra-operative anaesthetic requirements in patients undergoing elective ankle surgery in general anaesthesia.

Type of study

Prospective, randomized study of the intra-operative anaesthetic-sparing effects of etoricoxib premedication as compared to no NSAID preoperatively.

Methods

The intra-operative requirement of sevoflurane was studied in forty-four ASA 1–2 patients undergoing elective ankle day surgical in balanced general anaesthesia.

Primary study endpoint was end-tidal sevoflurane concentration to maintain Cerebral State Index of 40 – 50 during surgery.

Results

All anaesthesia and surgery was uneventful, no complications or adverse events were noticed. The mean end-tidal sevoflurane concentration intra-operatively was 1.25 (SD 0.2) and 0.91 (SD 0.2) for the pre and post-operative administered group of patients respectively (p < 0.0001). No other intra-operative differences could be noted. Emergence and recovery was rapid and no difference was noticed in time to discharge-eligible mean 52 minutes in both groups studied. In all 6 patients, 5 in the group receiving etoricoxib post-operatively, after surgery, and one in the pre-operative group required rescue analgesia before discharge from hospital. No difference was seen in pain or need for rescue analgesia, nausea or patients satisfaction during the first 24 postoperative hours.

Conclusion

Coxib premedication before elective day surgery has an anaesthetic sparing potential.
Expressing exogenous functional odorant receptors in cultured olfactory sensory neurons
Authors: Chen Huaiyang , Dadsetan Sepehr , Fomina Alla F , Gong Qizhi
Published: September 2008

Background

Olfactory discrimination depends on the large numbers of odorant receptor genes and differential ligand-receptor signaling among neurons expressing different receptors. In this study, we describe an in vitro system that enables the expression of exogenous odorant receptors in cultured olfactory sensory neurons. Olfactory sensory neurons in the culture express characteristic signaling molecules and, therefore, provide a system to study receptor function within its intrinsic cellular environment.

Results

We demonstrate that cultured olfactory sensory neurons express endogenous odorant receptors. Lentiviral vector-mediated gene transfer enables successful ectopic expression of odorant receptors. We show that the ectopically expressed mouse I7 is functional in the cultured olfactory sensory neurons. When two different odorant receptors are ectopically expressed simultaneously, both receptor proteins co-localized in the same olfactory sensory neurons up to 10 days in vitro.

Conclusion

This culture technique provided an efficient method to culture olfactory sensory neurons whose morphology, molecular characteristics and maturation progression resembled those observed in vivo. Using this system, regulation of odorant receptor expression and its ligand specificity can be studied in its intrinsic cellular environment.
Genital and cutaneous human papillomavirus (HPV) types in relation to conjunctival squamous cell neoplasia: A case-control study in Uganda
Authors: de Koning Maurits NC , Waddell Keith , Magyezi Joseph , Purdie Karin , Proby Charlotte , Harwood Catherine , Lucas Sebastian , Downing Robert , Quint Wim GV , Newton Robert
Published: September 2008

Background

We investigated the role of infection with genital and cutaneous human papillomavirus types (HPV) in the aetiology of ocular surface squamous neoplasia (which includes both conjunctival intraepithelial neoplasia (CIN) and carcinoma) using data and biological material collected as part of a case-control study in Uganda.

Results

Among 81 cases, the prevalence of genital and cutaneous HPV types in tumour tissue did not differ significantly by histological grade of the lesion. The prevalence of genital HPV types did not differ significantly between cases and controls (both 38%; Odds ratio [OR] 1.0, 95% confidence interval [CI] 0.4–2.7, p = 1.0). The prevalence of cutaneous HPV types was 22% (18/81) among cases and 3% (1/29) among controls (OR 8.0, 95% CI 1.0–169, p = 0.04).

Conclusion

We find no evidence of an association between genital HPV types and ocular surface squamous neoplasia. The prevalence of cutaneous HPV was significantly higher among cases as compared to controls. Although consistent with results from two other case-control studies, the relatively low prevalence of cutaneous HPV types among cases (which does not differ by histological grade of tumour) indicates that there remains considerable uncertainty about a role for cutaneous HPV in the aetiology of this tumour.
Transcriptomic signature of Bexarotene (Rexinoid LGD1069) on mammary gland from three transgenic mouse mammary cancer models
Authors: Abba Martin C , Hu Yuhui , Levy Carla C , Gaddis Sally , Kittrell Frances S , Zhang Yun , Hill Jamal , Bissonnette Reid P , Medina Daniel , Brown Powel H , Aldaz C Marcelo
Published: September 2008

Background

The rexinoid bexarotene (LGD1069, Targretin) is a highly selective retinoid × receptor (RXR) agonist that inhibits the growth of pre-malignant and malignant breast cells. Bexarotene was shown to suppress the development of breast cancer in transgenic mice models without side effects. The chemopreventive effects of bexarotene are due to transcriptional modulation of cell proliferation, differentiation and apoptosis. Our goal in the present study was to obtain a profile of the genes modulated by bexarotene on mammary gland from three transgenic mouse mammary cancer models in an effort to elucidate its molecular mechanism of action and for the identification of biomarkers of effectiveness.

Methods

Serial analysis of gene expression (SAGE) was employed to profile the transcriptome of p53-null, MMTV-ErbB2, and C3(1)-SV40 mammary cells obtained from mice treated with bexarotene and their corresponding controls.

Results

This resulted in a dataset of approximately 360,000 transcript tags representing over 20,000 mRNAs from a total of 6 different SAGE libraries. Analysis of gene expression changes induced by bexarotene in mammary gland revealed that 89 genes were dysregulated among the three transgenic mouse mammary models. From these, 9 genes were common to the three models studied.

Conclusion

Analysis of the indicated core of transcripts and protein-protein interactions of this commonly modulated genes indicate two functional modules significantly affected by rexinoid bexarotene related to protein biosynthesis and bioenergetics signatures, in addition to the targeting of cancer-causing genes related with cell proliferation, differentiation and apoptosis.
Threshold for detection of diabetic peripheral sensory neuropathy using a range of research grade monofilaments in persons with Type 2 diabetes mellitus
Authors: Thomson Mary P , Potter Julia , Finch Paul M , Paisey Richard B
Published: September 2008

Aims

To identify the threshold of reduced sensory perception in Type 2 diabetes mellitus (Type 2 DM) using a range of research grade monofilaments.

Methods

Three groups of participants were recruited into a between subject, cross‐sectional study. Group 1(NEW), persons with Type 2 DM diagnosed for less than 2 years (n = 80); Group 2 (EST) persons with Type 2 DM diagnosed for more than 2 years (n = 91), and Group 3, a Comparison group without Type 2 DM (n = 73), resulted in a total study population, n = 244. Research grade monofilaments (2, 4, 6, 8 and 10‐gram) were employed using standardised protocol, at 6 sites on the plantar aspect of both feet. The demographic and anthropometric measures of gender, age, height, weight, body mass index (BMI), blood pressure and duration of Type 2 DM since diagnosis (if applicable) of the participants were analysed.

Results

Perception of the research grade monofilaments differed significantly between the 3 groups (p < 0.05). The 6‐gram monofilament was found to be the threshold of normal perception, based on 90% of the Comparison group perceiving the 6‐gram monofilament at all sites in contrast to 64% of NEW and 48% of EST groups.

Conclusion

The 6‐gram monofilament was identified as the threshold of normal sensory perception. Inability to perceive the 6‐gram monofilament indicates, when using the method described in this study, that diminution of sensory perception is evident. Employing a range of monofilaments, 6, 8 and 10‐grams in Type 2 DM foot screening would allow the clinical detection of deteriorating sensory perception and enable implementation of foot protection strategies at an earlier stage than is currently practised.
Use of T2-weighted magnetic resonance imaging of the optic nerve sheath to detect raised intracranial pressure
Authors: Geeraerts Thomas , Newcombe Virginia FJ , Coles Jonathan P , Abate Maria Giulia , Perkes Iain E , Hutchinson Peter JA , Outtrim Jo G , Chatfield Dot A , Menon David K
Published: September 2008

Introduction

The dural sheath surrounding the optic nerve communicates with the subarachnoid space, and distends when intracranial pressure is elevated. Magnetic resonance imaging (MRI) is often performed in patients at risk for raised intracranial pressure (ICP) and can be used to measure precisely the diameter of optic nerve and its sheath. The objective of this study was to assess the relationship between optic nerve sheath diameter (ONSD), as measured using MRI, and ICP.

Methods

We conducted a retrospective blinded analysis of brain MRI images in a prospective cohort of 38 patients requiring ICP monitoring after severe traumatic brain injury (TBI), and in 36 healthy volunteers. ONSD was measured on T2-weighted turbo spin-echo fat-suppressed sequence obtained at 3 Tesla MRI. ICP was measured invasively during the MRI scan via a parenchymal sensor in the TBI patients.

Results

Measurement of ONSD was possible in 95% of cases. The ONSD was significantly greater in TBI patients with raised ICP (>20 mmHg; 6.31 ± 0.50 mm, 19 measures) than in those with ICP of 20 mmHg or less (5.29 ± 0.48 mm, 26 measures; P < 0.0001) or in healthy volunteers (5.08 ± 0.52 mm; P < 0.0001). There was a significant relationship between ONSD and ICP (r = 0.71, P < 0.0001). Enlarged ONSD was a robust predictor of raised ICP (area under the receiver operating characteristic curve = 0.94), with a best cut-off of 5.82 mm, corresponding to a negative predictive value of 92%, and to a value of 100% when ONSD was less than 5.30 mm.

Conclusions

When brain MRI is indicated, ONSD measurement on images obtained using routine sequences can provide a quantitative estimate of the likelihood of significant intracranial hypertension.
Partial pressure of end-tidal carbon dioxide successful predicts cardiopulmonary resuscitation in the field: a prospective observational study
Authors: Kolar Miran , Križmarić Miljenko , Klemen Petra , Grmec Štefek
Published: September 2008

Introduction

Prognosis in patients suffering out-of-hospital cardiac arrest is poor. Higher survival rates have been observed only in patients with ventricular fibrillation who were fortunate enough to have basic and advanced life support initiated soon after cardiac arrest. An ability to predict cardiac arrest outcomes would be useful for resuscitation. Changes in expired end-tidal carbon dioxide levels during cardiopulmonary resuscitation (CPR) may be a useful, noninvasive predictor of successful resuscitation and survival from cardiac arrest, and could help in determining when to cease CPR efforts.

Methods

This is a prospective, observational study of 737 cases of out-of-hospital cardiac arrest. The patients were intubated and measurements of end-tidal carbon dioxide taken. Data according to the Utstein criteria, demographic information, medical data, and partial pressure of end-tidal carbon dioxide (PetCO2) values were collected for each patient in cardiac arrest by the emergency physician. We hypothesized that an end-tidal carbon dioxide level of 1.9 kPa (14.3 mmHg) or more after 20 minutes of standard advanced cardiac life support would predict restoration of spontaneous circulation (ROSC).

Results

PetCO2 after 20 minutes of advanced life support averaged 0.92 ± 0.29 kPa (6.9 ± 2.2 mmHg) in patients who did not have ROSC and 4.36 ± 1.11 kPa (32.8 ± 9.1 mmHg) in those who did (P < 0.001). End-tidal carbon dioxide values of 1.9 kPa (14.3 mmHg) or less discriminated between the 402 patients with ROSC and 335 patients without. When a 20-minute end-tidal carbon dioxide value of 1.9 kPa (14.3 mmHg) or less was used as a screening test to predict ROSC, the sensitivity, specificity, positive predictive value, and negative predictive value were all 100%.

Conclusions

End-tidal carbon dioxide levels of more than 1.9 kPa (14.3 mmHg) after 20 minutes may be used to predict ROSC with accuracy. End-tidal carbon dioxide levels should be monitored during CPR and considered a useful prognostic value for determining the outcome of resuscitative efforts and when to cease CPR in the field.
Queer Medieval
Authors: Drake Graham N.
Published: September 2008

Queer medievalists deal with four major methodological questions: historical contextualization and nomenclature; the actuality of embodied erotic experience; the elision or erasure of female same-sex eroticism; and the periodization of history and the purpose of its study. Two recent works of queer medievalism explore and apply these methodologies: Glenn Burger and Steven F. Kruger, Queering the Middle Ages, and Karma Lochrie, Heterosyncrasies: Female Sexuality When Normal Wasn't. The contributors to Burger and Kruger's volume examine both medieval visual and verbal texts and also apply medievalism as an excluded middle that uncovers aspects of queer eroticism in the postmodern moment and questions periodization. Lochrie detaches the heteronormative assumptions of medieval scholars from literary and historical texts representing diverse female sexualities. The reviewer argues that queer medievalism attends to unexplored complexities of nonnormative sexuality in history but also may obscure the recovery of same-sex eroticism in the Middle Ages.
All EGF(ErbB) receptors have preformed homo- and heterodimeric structures in living cells
Authors: Tao Rong-Hua , Maruyama Ichi N.
Published: September 2008

The epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases, also known as ErbB or HER, plays crucial roles in the development of multicellular organisms. Mutations and over-expression of the ErbB receptors have been implicated in a variety of human cancers. It is widely thought that the ErbB receptors are located in the plasma membrane, and that ligand binding to the monomeric form of the receptors induces its dimeric form for activation. However, it still remains controversial whether prior to ligand binding the receptors exist as monomers or dimers on the cell surface. Using bimolecular fluorescence complementation (BiFC) assays in the present study, we demonstrate that in the absence of bound ligand, all the ErbB family members have preformed, yet inactive, homo- and heterodimers on the cell surface, except for ErbB3 homodimers and heterodimers with cleavable ErbB4, which exist primarily in the nucleus. BiFC assays of the dimerization have also suggested that the ligand-independent dimerization of the ErbB receptors occurs in the endoplasmic reticulum (ER) before newly synthesized receptor molecules reach the cell surface. Based on BiFC and mammalian two-hybrid assays, it is apparent that the intracellular domains of the receptors are responsible for the spontaneous dimer formation. These provide new insights into an understanding of transmembrane signal transduction mediated by the ErbB family members, and are relevant to the development of anti-cancer drugs.
Effect of curing characteristics on residual stress generation in polymethyl methacrylate bone cements
Authors: Hingston J A , Dunne N J , Looney L , McGuinness G B
Published: September 2008

Residual stresses resulting from the shrinkage of polymethyl methacrylate (PMMA) bone cement have been implicated in the formation of cracks in cement mantles following total hip arthroplasty. This study investigates whether two such cements, with differentiated solidification characteristics (i.e. working and setting times), display significant differences in their residual stress characteristics in an experiment designed to replicate the physical conditions of total hip arthroplasty. Experiments were performed using a representative femoral construct to measure and compare the temperatures and residual strains developed for standard PMMA cement mantles (CMW® 1 Gentamicin) and slow curing cement mantles (SmartSet® HV Gentamicin) during and following polymerization. These experimental results revealed no statistically significant difference ( t-test, p > 0.05) for peak exotherm temperature and residual strain levels between the cements (measured after 3 h). The tailored polymerization characteristics of the slow-curing cement do not significantly affect residual stress generation, compared with the standard cement. It is often considered that residual stresses significantly relax following polymerization and before biomechanical loads are first applied during rehabilitation (up to 3 days later). This was examined for durations of 18 h to 3 days. Axial strains in the model femur and stem reduced by averages of 5.5 and 7.9 per cent respectively, while hoop strains in the stem exhibited larger reductions. An axisymmetric transient thermoelastic finite element model of the experiment was developed, allowing residual stresses to be predicted based on differential scanning calorimetry (DSC) measurements of the heat released throughout the exothermic curing reaction. The model predictions closely replicated the experimental measurements of both temperature and residual strain at 3 h, suggesting that residual strains can be fully accounted for by the thermal contraction mechanism associated with cooling after solidification.
Biomechanical and radiographic evaluation of an ovine model for the human lumbar spine
Authors: Easley N E , Wang M , McGrady L M , Toth J M
Published: September 2008

While various species of animal models have been used in preclinical investigations of spinal implant devices to assess their biological adaptation and biomechanical performance, few studies have made comprehensive comparisons to validate their suitability of modelling the human spine. The purpose of this study was to assess essential biomechanical behaviours and disc morphology of the ovine lumbar model. Flexibility testing was conducted on the spines (L3—L4 and L4—L5) of nine skeletally matured sheep. Segmental rotation and intradiscal pressure were measured and load sharing between the intervertebral disc and posterior elements were calculated on the basis of a simplified parallel spring model. Following the tests, the spinal segments were sectioned into a series of sagittal slabs, and transverse radiographs of these slabs were taken to evaluate the variation in the disc height and end-plate curvature. Comparing the biomechanical and radiographic results with published data on the human lumbar spine, good comparability between the ovine and cadaveric lumbar spines was found in terms of the general disc shape and in most of the biomechanical parameters including the range of motion, neutral zone, and load sharing between the intervertebral disc and posterior elements. A few distinctive differences were also found between the two, including flatter sagittal alignment, smaller disc dimensions, and greater lateral bending motion in the ovine model.
A statistical model and simulator for cardiovascular pressure signals
Authors: Staats C , Austin D , Aboy M
Published: September 2008

Physiological signal simulators are often used to conduct validation studies of commercially available devices such as oscillometric non-invasive blood pressure (NIBP) monitors. Numerous assessment studies have been conducted using simulators to validate commercial NIBP monitors. While there are several simulators commercially available to evaluate oscillometric NIBP devices, currently there are no simulators designed to validate invasive pressure signal devices. A statistical model and simulator for invasive cardiovascular pressure signals such as arterial blood pressure and intracranial pressure are described. The model incorporates the effects of respiration on pressure signals and can be used to generate synthetic signals with time and frequency domain characteristics matching any desired subject population. Additionally, the way that noise and artefacts typically present in real pressure signals should be modelled is described. The proposed statistical model is a useful tool for validation of algorithms designed to process or analyse biomedical pressure signals to estimate parameters of clinical interest such as the cardiac frequency, heart rate variability, respiratory frequency, and pulse pressure variation in the presence of noise. The model can be used to simulate signals in order to validate commercial devices that process and analyse invasive pressure signals.
Alteration of the amount and morphology of wear particles by the addition of loading profile transitions during artificial hip wear testing
Authors: Shorez J P , Harding T S , Atkinson P J , Walter N
Published: September 2008

Current validation tests of total hip arthroplasty endo-prostheses capture only a single activity performed by patients: continuous walking. A more representative test that includes transitions from a static loaded position to dynamic motion would simulate common motions by patients in which they change from standing to walking. The introduction of such transitions into a traditional test protocol could provide insight into actual wear behaviours and more realistic wear particle properties such as size and shape. First, the introduction of transitions will increase the measured wear rate. Second, the amount of wear will be positively correlated to the number of transitions per day. Finally, the size and shape of polyethylene particle produced via testing with transitions will differ from those of a conventional continuous walking test. Three identical sets of four cobalt chromium femoral heads and sterilized acetabular cups sterilized in ethylene oxide were tested in 30 per cent bovine serum under three conditions: continuous walking (0 transitions/day), 10 transitions/day, and 100 transitions/day. A day was defined as 2500 steps. The static and peak dynamic loads were 260 N and 1.9 kN respectively. A testing duration of 106 cycles was completed for each of the three tests. The wear rate was found to be inversely related to the number of transitions. Particle analysis showed that the particle size decreased as the number of transitions increased. Particles from the 100 transitions/day test were more fibular and produced more particles of the size known to promote an immune reactive response. Contrary to our hypothesis, as the number of transitions performed by patients increased, the wear rate and accumulated wear decreased. In addition, as the number of transitions increased, a larger percentage of wear particles were in the submicron size range. Consequently, despite a decrease in wear due to the presence of loading profile transitions, there is a potentially greater risk of osteolysis owing to the increased production of immunoreactive particles.
Biomechanical comparison of three second-generation reconstruction nails in an unstable subtrochanteric femur fracture model
Authors: Heiney J , Battula S , Njus G , Ruble C , Vrabec G
Published: September 2008

The purpose of this study is to determine if a biomechanical difference exists in dynamic stiffness, fatigue life, and fracture site displacement by comparing three cephalomedullary reconstruction nails. An examination was made of the Biomet Uniflex reconstruction nail, the Biomet Vector nail, and the Stryker Howmedica Long Gamma nail in the fixation of an unstable subtrochanteric femur fracture model, using a synthetic bone model. Mean stiffness for each nail was initially determined in control specimens (i.e. no fracture and no instrumentation). The nail stiffness values were 1764.0 N/mm (controls), 373.61 N/mm (Uniflex), 294.27 N/mm (vector), and 656.36 N/mm (Gamma). The Gamma was statistically stiffer than the Uniflex and Vector ( p<0.002). Mean fatigue life measurements were: Uniflex at 52 891 cycles, failing at the most distal of the proximal two screw holes; Vector at 45 344 cycles, failing in the nail at the level of the fracture site; Gamma at 88 748 cycles failing at the lag screw hole. The p value between the Gamma and Vector was less than 0.01 and between Gamma and Uniflex was less than 0.05. The mean maximal axial displacement at the fracture site was 2.448 mm, 2.305 mm, and 0.790 mm for the Uniflex, Vector and Gamma, respectively. The p value between the Gamma and the other nails was < 0.01. The mean maximal transverse displacement at the fracture site was 1.223 mm, 1.197 mm, and 0.280 mm respectively. The p value between the Long Gamma and the other two nails was < 0.01. In conclusion, the Long Gamma nail demonstrated statistically significant fixation superiority in stiffness, resistance to fatigue, and fracture site displacement compared to the Uniflex and Vector nails. This biomechanical information may aid in choosing implants for fixation of unstable, subtrochanteric femur fractures.
Wear resistance of highly cross-linked and remelted polyethylenes after ion implantation and accelerated ageing
Authors: Medel F J , Puértolas J A
Published: September 2008

Ion implantation may provide medical polyethylenes with excellent mechanical and tribological properties, helping to lower the risk of long-term osteolysis. Highly cross-linked and remelted polyethylenes, materials currently used as soft components in artificial joints, were implanted with N+ and He+ ions at different ion fluences. The mechanical and tribological properties under distilled water lubrication at body temperature were assessed after ion implantation by means of microhardness and pin-on-disc tests respectively. Thus, the influences of the ionic species and implantation dose on surface hardness, friction coefficient, and wear factor were fully characterized. Furthermore, the tribological behaviour was evaluated after an accelerated ageing protocol (120 °C for 36 h). Ion implantation increased the surface hardness, as well as friction coefficients, and decreased the wear factors especially at the highest doses. Also, even though all artificially aged materials showed a worse wear behaviour, polyethylenes implanted with either N+ or He+ at the highest doses maintained a relatively good wear factor in comparison with the aged non-implanted material. The origins of these modifications are discussed according to the effects of ion implantation on the microstructure of the polymer.
The wear of high-carbon metal-on-metal bearings after different heat treatments
Authors: Kinbrum A , Unsworth A
Published: September 2008

To study the tribological performance of metal-on-metal hip joint resurfacings, the wear performance of three pairs of Co—Cr—Mo alloy samples (pins and plates) were tested in a multidirectional pin-on-plate wear machine. An ‘as-cast’, a single-heat-treated, and a double-heat-treated set of specimens were tested to 3×106 cycles. The two heat treatments resulted in partial and full solution of the carbides into the matrix. An increasing trend in wear rate was found from ‘as-cast’ to the double-heat-treated specimens. The as-cast specimens showed the lowest wear rate (1.69×10−6 mm3/N m), the reduced carbide samples had the next lowest wear rate (2.1×10−6 mm3/N m), while the specimens without carbides wore the most (2.41×10−6 mm3/N m).