bluuebunny/crossref_metadata_2025 huggingface dataset:
A ryanodine receptor-dependent Cai2+ asymmetry at Hensen's node mediates avian lateral identity
Authors: Garic-Stankovic Ana , Hernandez Marcos , Flentke George R. , Zile Maija H. , Smith Susan M.
Published: August 2008

In mouse, the establishment of left-right (LR) asymmetry requires intracellular calcium (Cai2+) enrichment on the left of the node. The use of Cai2+ asymmetry by other vertebrates, and its origins and relationship to other laterality effectors are largely unknown. Additionally, the architecture of Hensen's node raises doubts as to whether Cai2+ asymmetry is a broadly conserved mechanism to achieve laterality. We report here that the avian embryo uses a left-side enriched Cai2+ asymmetry across Hensen's node to govern its lateral identity. Elevated Cai2+ was first detected along the anterior node at early HH4, and its emergence and left-side enrichment by HH5 required both ryanodine receptor (RyR) activity and extracellular calcium, implicating calcium-induced calcium release (CICR) as the novel source of the Cai2+. Targeted manipulation of node Cai2+ randomized heart laterality and affected nodal expression. Bifurcation of the Cai2+field by the emerging prechordal plate may permit the independent regulation of LR Cai2+ levels. To the left of the node, RyR/CICR and H+V-ATPase activity sustained elevated Cai2+. On the right, Cai2+ levels were actively repressed through the activities of H+K+ATPase and serotonin-dependent signaling, thus identifying a novel mechanism for the known effects of serotonin on laterality. Vitamin A-deficient quail have a high incidence of situs inversus hearts and had a reversed calcium asymmetry. Thus, Cai2+ asymmetry across the node represents a more broadly conserved mechanism for laterality among amniotes than had been previously believed.
Temporal regulation of ephrin/Eph signalling is required for the spatial patterning of the mammalian striatum
Authors: Passante Lara , Gaspard Nicolas , Degraeve Mélanie , Frisén Jonas , Kullander Klas , De Maertelaer Viviane , Vanderhaeghen Pierre
Published: August 2008

Brain structures, whether mature or developing, display a wide diversity of pattern and shape, such as layers, nuclei or segments. The striatum in the mammalian forebrain displays a unique mosaic organization (subdivided into two morphologically and functionally defined neuronal compartments: the matrix and the striosomes) that underlies important functional features of the basal ganglia. Matrix and striosome neurons are generated sequentially during embryonic development, and segregate from each other to form a mosaic of distinct compartments. However, the molecular mechanisms that underlie this time-dependent process of neuronal segregation remain largely unknown. Using a novel organotypic assay, we identified ephrin/Eph family members as guidance cues that regulate matrix/striosome compartmentalization. We found that EphA4 and its ephrin ligands displayed specific temporal patterns of expression and function that play a significant role in the spatial segregation of matrix and striosome neurons. Analysis of the striatal patterning in ephrin A5/EphA4 mutant mice further revealed the requirement of EphA4 signalling for the proper sorting of matrix and striosome neuronal populations in vivo. These data constitute the first identification of genes involved in striatal compartmentalization, and reveal a novel mechanism by which the temporal control of guidance cues enables neuronal segregation, and thereby the generation of complex cellular patterns in the brain.
Out-of-hours cover in oral and maxillofacial surgery
Authors: Reddy-Kolanu G , Ethunandan M , Anand R , Ilankovan V
Published: August 2008

The European Working Time Directive (EWTD) has required all departments to re think staffing arrangements to provide out-of-hours ser vices. Large departments with man y junior doctors can continue to have oral and maxillofacial surgery (OMFS) SHOs covering the out-of-hours ser vice without exceeding the constraints of EWTD. For smaller departments the choice has been either to close the on-call service and centralise it in a larger department or to have a specialty cross-cover arrangement. The problems of cross-cover might be more apparent in OMFS than in other hospital specialties due to other medical staff possessing a negligible knowledge of dental pathology.
Coding: an audit of its accuracy and implications
Authors: Joy R , Velagala S , Akhtar S
Published: August 2008

As part of ongoing changes undergone by the NHS in recent years, the Department of Health (DH) published new reforms proposing payment by results. This was introduced in April 2004. Under this system, providers are no longer paid by block contracts but by activity adjusted for case mix.
The surgical workforce: where next?
Authors: Greatorex Robert , Cripps Jo
Published: August 2008

The surgical workforce is rapidly changing and it would appear that few have an accurate grasp of the current situation. Modernising Medical Careers (MMC) and the Medical Training Application Service wreaked havoc, leaving many trainees confused about their current situation and uncertain about their future career prospects; there is no clarity on staff grade numbers and a significant number of CCT [Certificate of Completion of Training]-holders are struggling to find a consultant post. Lord Darzi's review has called for integrated workforce planning, occurring at the local level with employers, regionally with oversight from the strategic health authorities and nationally with a newly established 'centre of excellence' for workforce planning, to be supported at each level by professional advisor y groups. What are the implications for the profession?
Taking the baton
Authors: Black John
Published: August 2008

Writing as the Olympic games are about to begin, the title of my predecessor Bernie Ribeiro's last newsletter, 'Passing the baton,' is apt. I will do my best not to drop it but I have a hard act to follow. In his farewell message Bernie mentioned the number of times the Chinese lucky number eight was a landmark for many of the major events of his life and the same applies to me. At the age of eight I met the great Aneurin Bevan in my parents' house in Wallsend-on-Tyne. My father was a local politician (Labour of course on Tyneside) and great was the excitement over a visit from the man who implemented the vision of Beveridge and founded the National Health Service, now 60 years old, in 1948. I qualified in 1968, became a consultant in Worcester in 1978 and became your president in the current year 2008.
Effects of Delayed Sample Processing and Freezing on Serum Concentrations of Selected Nutritional Indicators
Authors: Drammeh Bakary S , Schleicher Rosemary L , Pfeiffer Christine M , Jain Ram B , Zhang Mindy , Nguyen Phuong Hong
Published: August 2008

Background: Environmental conditions during sample processing, shipping, and storage are often suboptimal, particularly in less developed countries. We used samples from US volunteers to investigate the effects of delayed whole blood (WB) processing and delayed freezing of serum on selected nutritional indicators.

Methods: WB tubes (n = 35) were either stored at 32 °C for up to 3 days before serum separation or centrifuged within 2 h of collection; serum samples were stored at 11 °C for up to 14 days to simulate delayed shipping. We assessed analyte stability by comparing results with data from optimally prepared/stored serum samples (<2 h on the clot, frozen at −70 °C) and by using clinical-acceptability criteria based on combined analytical imprecision and intraindividual biologic variability.

Results: Clinically acceptable changes in concentration varied from 3%–15%. Delayed WB processing did not unacceptably affect concentrations of carotenoids and vitamins B12, D, and E; however, we obtained clinically unacceptable changes for ferritin (+9%), soluble transferrin receptor (sTfR) (+5%), and folate (−30%) after 1 day, and for vitamin A (−10%) after 3 days. Delayed freezing of serum did not affect concentrations of ferritin, sTfR, carotenoids, and vitamins A, B12, and E; however, we obtained clinically unacceptable changes for vitamins C (−20%) and D (+7%) after 7 days and for folate after 14 days (−22%).

Conclusions: Despite substantial delays in WB processing or in the freezing of serum samples, most nutritional indicators showed remarkable stability. This information is important for both the design of field studies and the use of residual samples subjected to suboptimal preanalytical factors.
Notch Inhibition Promotes Human Embryonic Stem Cell-Derived Cardiac Mesoderm Differentiation
Authors: Jang Jiho , Ku Seung Yup , Kim Jung Eun , Choi Kyunghee , Kim Yoon Young , Kim Hee Sun , Oh Sun Kyung , Lee Eun Ju , Cho Hyun-Jai , Song Young Hwan , Lee Sang Hun , Lee Suk Ho , Suh Chang Suk , Kim Seok Hyun , Moon Shin Yong , Choi Young Min
Published: August 2008

The roles of Notch signaling in cardiac differentiation from murine embryonic stem cells have been well documented. We investigated whether Notch signaling plays a similar role in human embryonic stem cells (hESCs). Although, as previously reported, blocking Notch signaling via the addition of γ-secretase inhibitor (GSI) alone failed to affect hESC differentiation, we found that GSI plus reduced-volume culture medium (GSI/RVCM) accelerated mesodermal differentiation. GSI/RVCM conditions simultaneously suppressed commitment toward neuroectodermal lineages. Furthermore, sustained inhibition of Notch signaling further enhanced differentiation into cardiac mesoderm. Spontaneous beating activity was typically observed from 12 days after initiation of GSI treatment in RVCM. Moreover, hESC-derived cardiomyocytes expressed connexin 43 and possessed spontaneous calcium oscillations and cardiomyocyte beats coupled to neonatal rat cardiomyocytes when cocultured. These findings strongly suggest a distinct role for Notch signaling in the induction and specification of hESC-derived cardiac mesoderm in vitro.

Disclosure of potential conflicts of interest is found at the end of this article.
The Antitumorigenic Response of Neural Precursors Depends on Subventricular Proliferation and Age
Authors: Walzlein Joo-Hee , Synowitz Michael , Engels Boris , Markovic Darko S. , Gabrusiewicz Konrad , Nikolaev Evgeni , Yoshikawa Kazuaki , Kaminska Bozena , Kempermann Gerd , Uckert Wolfgang , Kaczmarek Leszek , Kettenmann Helmut , Glass Rainer
Published: August 2008

Glioblastomas, the most aggressive primary brain tumors, occur almost exclusively in adult patients. Neural precursor cells (NPCs) are antitumorigenic in mice, as they can migrate to glioblastomas and induce tumor cell death. Here, we show that the antitumor effect of NPCs is age-dependently controlled by cell proliferation in the subventricular zone (SVZ) and that NPCs accumulating at a glioblastoma are diverted from their normal migratory path to the olfactory bulb. Experimentally induced cortical glioblastomas resulted in decreased subventricular proliferation in adult (postnatal day 90) but not in young (postnatal day 30) mice. Adult mice supplied fewer NPCs to glioblastomas and had larger tumors than young mice. Apart from the difference in proliferation, there was neither a change in cell number and death rate in the SVZ nor a change in angiogenesis and immune cell density in the tumors. The ability to kill glioblastomas was similar in NPCs isolated from young and adult mice. The proliferative response of NPCs to glioblastomas depended on the expression of D-type cyclins. In young mice, NPCs express the cyclins D1 and D2, but the expression of cyclin D1 is lost during aging, and in adult NPCs only cyclin D2 remains. In young and adult cyclin D2-deficient mice we observed a reduced supply of NPCs to glioblastomas and the generation of larger tumors compared with wild-type mice. We conclude that cyclin D1 and D2 are nonredundant for the antitumor response of subventricular NPCs. Loss of a single D-type cyclin results in a smaller pool of proliferating NPCs, lower number of NPCs migrating to the tumor, and reduced antitumor activity.

Disclosure of potential conflicts of interest is found at the end of this article.
Secreted Frizzled-Related Protein-1 Enhances Mesenchymal Stem Cell Function in Angiogenesis and Contributes to Neovessel Maturation
Authors: Dufourcq Pascale , Descamps Betty , Tojais Nancy Ferreira , Leroux Lionel , Oses Pierre , Daret Daniéle , Moreau Catherine , Lamazière Jean-Marie Daniel , Couffinhal Thierry , Duplàa Cécile
Published: August 2008

Mesenchymal stem cell (MSC) transplantation offers a great angiogenic opportunity in vascular regenerative medicine. The canonical Wnt/β-catenin signaling pathway has been demonstrated to play an essential role in stem cell fate. Recently, genetic studies have implicated the Wnt/Frizzled (Fz) molecular pathway, namely Wnt7B and Fz4, in blood growth regulation. Here, we investigated whether MSC could be required in shaping a functional vasculature and whether secreted Frizzled-related protein-1 (sFRP1), a modulator of the Wnt/Fz pathway, could modify MSC capacities, endowing MSC to increase vessel maturation. In the engraftment model, we show that murine bone marrow-derived MSC induced a beneficial vascular effect through a direct cellular contribution to vascular cells. MSC quickly organized into primitive immature vessel tubes connected to host circulation; this organization preceded host endothelial cell (EC) and smooth muscle cell (SMC) recruitment to later form mature neovessel. MSC sustained neovessel organization and maturation. We report here that sFRP1 forced expression enhanced MSC surrounding neovessel, which was correlated with an increase in vessel maturation and functionality. In vitro, sFRP1 strongly increased platelet-derived growth factor-BB (PDGF-BB) expression in MSC and enhanced β-catenin-dependent cell-cell contacts between MSC themselves and EC or SMC. In vivo, sFRP1 increased their functional integration around neovessels and vessel maturation through a glycogen synthase kinase 3 beta (GSK3β)-dependent pathway. sFRP1-overexpressing MSC compared with control MSC were well elongated and in a closer contact with the vascular wall, conditions required to achieve an organized mature vessel wall. We propose that genetically modifying MSC to overexpress sFRP1 may be potentially effective in promoting therapeutic angiogenesis/arteriogenesis processes.

Disclosure of potential conflicts of interest is found at the end of this article.
The Transcription Factor Zfp281 Controls Embryonic Stem Cell Pluripotency by Direct Activation and Repression of Target Genes
Authors: Wang Zheng-Xu , Teh Christina Hui-Leng , Chan Caroline Man-Yee , Chu Ci , Rossbach Michael , Kunarso Galih , Allapitchay Tahira Bee , Wong Kee Yew , Stanton Lawrence W.
Published: August 2008

Oct4, Sox2, and Nanog are key components of a core transcriptional regulatory network that controls the ability of embryonic stem cells to differentiate into all cell types. Here we show that Zfp281, a zinc finger transcription factor, is a key component of the network and that it is required to maintain pluripotency. Zfp281 was shown to directly activate Nanog expression by binding to a site in the promoter in very close proximity to the Oct4 and Sox2 binding sites. We present data showing that Zfp281 physically interacts with Oct4, Sox2, and Nanog. Chromatin immunoprecipitation experiments identified 2,417 genes that are direct targets for regulation by Zfp281, including several transcription factors that are known regulators of pluripotency, such as Oct4, Sox2, and Nanog. Gene expression microarray analysis indicated that some Zfp281 target genes were activated, whereas others were repressed, upon knockdown of Zfp281. The identification of both activation and repression domains within Zfp281 suggests that this transcription factor plays bifunctional roles in regulating gene expression within the network.

Disclosure of potential conflicts of interest is found at the end of this article.
Altered bone mass, geometry and mechanical properties during the development and progression of type 2 diabetes in the Zucker diabetic fatty rat
Authors: Prisby Rhonda D , Swift Joshua M , Bloomfield Susan A , Hogan Harry A , Delp Michael D
Published: August 2008

Osteopenia and an enhanced risk of fracture often accompany type 1 diabetes. However, the association between type 2 diabetes and bone mass has been ambiguous with reports of enhanced, reduced, or similar bone mineral densities (BMDs) when compared with healthy individuals. Recently, studies have also associated type 2 diabetes with increased fracture risk even in the presence of higher BMDs. To determine the temporal relationship between type 2 diabetes and bone remodeling structural and mechanical properties at various bone sites were analyzed during pre-diabetes (7 weeks), short-term (13 weeks), and long-term (20 weeks) type 2 diabetes. BMDs and bone strength were measured in the femora and tibiae of Zucker diabetic fatty rats, a model of human type 2 diabetes. Increased BMDs (9–10%) were observed in the distal femora, proximal tibiae, and tibial mid- shafts in the pre-diabetic condition that corresponded with higher plasma insulin levels. During short- and long-term type 2 diabetes, various parameters of bone strength and BMDs were lower (9–26%) in the femoral neck, distal femora, proximal tibiae, and femoral and tibial mid-shafts. Correspondingly, blood glucose levels increased by 125% and 153% during short- and long-term diabetes respectively. These data indicate that alterations in BMDs and bone mechanical properties are closely associated with the onset of hyperinsulinemia and hyperglycemia, which may have direct adverse effects on skeletal tissue. Consequently, disparities in the human literature regarding the effects of type 2 diabetes on skeletal properties may be associated with the bone sites studied and the severity or duration of the disease in the patient population studied.
A Role for SPE in Meeting Vital Human Needs
Authors: Ebenhack Mary Jeanette , Ebenhack Ben W.
Published: August 2008

Twenty years ago an effort was mounted at the Frederick Douglass Institute for African and Africa-American Studies at the University of Rochester, USA, based on the idea that energy had a critical role to play in assisting developing nations overcome the scourge of poverty. What became the AHEAD Energy Corporation also proposed that locally-available hydrocarbons, especially natural gas, could ignite rapid development.

Although "AHEAD" was an acronym that stood for Access to Hydrocarbon Energy for African Development, it is perhaps serendipitous that these ideas could rightly be said to have been ahead of their time. Until recently, energy's role in development has not been understood. Whereas it is easy for the common person to recognize the need for food, water, housing, education and medical care, it has required long arduous efforts to get international development aid professionals to grasp the idea that energy is perhaps the primary key to economic and social development.

Energy: the invisible need

Energy does not directly feed, house, or clothe people. But energy services facilitate the production of food, construction materials, and textiles. The "causal chain" leading from energy resources to improvements in people's lives can be long and complex, requiring many other non-energy inputs.1 Moreover, energy services often bring improvements in several areas at once. For example, consider all the uses to which electric power can be directed: lighting, refrigeration, communication, use of appliances, cooking, space heating and cooling, and even transportation.
On the Case: Designing an Interdisciplinary Learning Game with Neuromancer
Authors: Slocombe Will , Price Chris
Published: August 2008

Computer games are increasingly being considered as a means of promoting learning, especially the use of commercial off-the-shelf (COTS) games in the classroom. This article extends this idea by proposing an innovative method of fostering interdisciplinary collaboration through the design of computer games. The game to be developed, On the Case, is based on William Gibson's seminal Neuromancer, and will be used to augment and enhance the learning experiences of literary studies students studying this text. However, these users will also assist in the design process before a prototype version of the game is developed by peers on game-design degree programmes. The article offers an overview of the design considerations behind the game, primarily in terms of the intellectual engagement such a game will promote, the learning it is designed to foster, and the mechanisms – game-play, environment, and learning design – through which it will do so.
Playing by the Rules: Instruction and Acculturation in Role-Playing Games
Authors: Neuenschwander Bryn
Published: August 2008

The open-ended, informal, and socially negotiated nature of role-playing games creates a distinct learning challenge for newcomers to the hobby. The explicit rules of the game provide only an incomplete framework for structuring the actions of players, and the expectations and mores of a given group will add other, unspoken rules that discourage or reward certain patterns of behavior. Through a combination of casual instruction, mimesis, and situated learning, new players become acculturated to the ways of both role-playing games in general and specific games in particular. Online resources can facilitate this process, by placing individuals in contact with a wider network of fellow hobbyists, but the limited channel of communication available online also restricts the social cues that could otherwise contribute to learning.
The Effects of Incomplete Personal Capability Knowledge and Overconfidence on Employment Contract Selection
Authors: Hyatt Troy A. , Taylor Mark H.
Published: August 2008

The purpose of this paper is to examine the effects of workers not knowing their performance capability for job-related skills on their contract selection decisions. We hypothesize that participants with incomplete personal capability knowledge will tend to be overconfident about their abilities and that such overconfidence will affect contract choice (they will incorrectly select a performance-based contract when they should select a fixed-pay contract) and result in lower participant earnings. We also hypothesize that once these participants learn their actual performance capability they will be more likely to switch contracts in a subsequent period than participants who know their performance capability at the time of initial contract selection. We design an experiment to test our predictions and find strong support. The paper also discusses implications of the findings, limitations of the study, and suggestions for future research.
Behavioral Effects of Nonfinancial Performance Measures: The Role of Procedural Fairness
Authors: Lau Chong M. , Moser Antony
Published: August 2008

Recent suggestions that nonfinancial measures are essential to overcome the inadequacies of traditional financial measures have led to the widespread adoption of such measures. It is, however, unclear how employees react to these new measures. This study hypothesizes that favorable employee behaviors will only occur if employees perceive performance evaluation criteria as fair. It is therefore important to ascertain if the use of nonfinancial measures as performance criteria is procedurally fair. Based on a sample of 149 managers from the United Kingdom, the results indicate that the use of nonfinancial performance measures was perceived as procedurally fair. We also find that such perceptions are associated with higher organizational commitment which, in turn, enhances employee job performance.
An Empirical Investigation of the Effects of SRS Technology on Introductory Managerial Accounting Students
Authors: Edmonds Christopher T. , Edmonds Thomas P.
Published: August 2008

To investigate whether student response system (SRS) technology increases student exam performance, we conduct a quasi-experiment using six introductory managerial accounting courses. Three courses were taught using SRS technology and three were taught without using SRS technology. The students in the SRS courses performed on average 3.15 percentage points better than students in the non-SRS courses after controlling for age, gender, prior GPA, and ACT score. SRS technology was more beneficial to students with the lowest prior GPAs. The study found evidence that SRS technology helps these low-GPA students without having a negative effect on high-GPA students.
Simply Academic: Linking Reporting Environments
Authors: Stuebs Martin T.
Published: August 2008

This instructional case attempts to connect the environmental incentives and ethical issues from two different reporting environments. It provides two different scenarios that allow students to identify and grapple with multiple incentives and resultant ethical dilemmas present in the academic reporting environment. A summary then requires students to link stakeholders, activities, incentives, and dilemmas in the academic environment to corresponding situations in the financial reporting environment. The purpose of the case is threefold: (1) It makes students aware of the incentives and ethical issues present in various reporting environments. (2) By explicitly linking the academic and financial reporting environments, students see the relevance of ethics in their current lives and are motivated to develop ethical habits now in order to prepare for the challenges that will occur later in their careers. (3) The case forces students to practice making decisions in situations with conflicting incentives and ambiguous or nonexistent legal guidance. Strong conflicting incentives can cloud and compromise even the purest of intentions. Dealing with these conflicts early and often can mature one's judgments and improve the decision-making process.
Genetic structure of the Anthyllis vulneraria L. s. l. species complex in Estonia based on AFLPs
Authors: Köster Egle , Bitocchi Elena , Papa Roberto , Pihu Silvia
Published: August 2008

Anthyllis vulneraria L. (Fabaceae) s. lato includes many cryptic taxa, ranging from 25 to 60 subspecies according to different authors. The delimitation of intraspecific taxa of A. vulneraria s. lato has always been complicated and inconsistent. Different data sets (multivariate analyses of morphological variation, allozymes, chloroplast SSRs and ITS) have not resolved the existing problem with distinguishing some subspecies. We used the amplified fragment length polymorphism (AFLP) analysis to describe the differentiation in this species complex and to characterize variation on a geographic scale. Some correlation was found between genetic variability and geographic distribution (western-eastern directional variation), but AFLP data analysis did not reveal clear intraspecific structure of the seven analysed taxa. The analysed specimens did not comprise groups correlated with the subspecies.
New chorological data for flora of the Pannonian region of Serbia
Authors: Savić Dragiša , Anačkov Goran , Boža Pal
Published: August 2008

The northern part of Serbia, known as Pannonian Serbia, is a lowland region. The autochthonous (indigenous) flora is classified as either steppe, forest-steppe, sand dune or salt flat. Most of the area has been developed agriculturally, thereby reducing the amount of land containing preserved habitats. The flora of this region was collected over a period of several years, supplying new data on the distribution of numerous plant species. The first data on the distribution of flora in Pannonian Serbia for Humulus scandens and Ophris scolopax subsp. Cornuta is presented in this study. The local regions cited were the first time precisely recorded regions were made after a period of over 100 years, for Cardamine impatiens, Monotropa hypopitys subsp. hypopitys, Ononis pusilla, Globularia punctata, Gymnadenia odoratissima and Carex brevicollis. The groups, Peucedanum carvifola and Galium tenuissimum, quite rare in the northern part of Serbia, were found at new localities. In order to present the data, the authors used the method of indirect mapping on UTM grid, with 10 × 10 km as the basic unit. This method is compatible with the edition Atlas Florae Europaeae.
Seedling establishment of two shrubby plants native to the Sierra Nevada mountain range
Authors: Serrano-Bernardo Francisco , Rosúa-Campos José
Published: August 2008

The Sierra Nevada mountain range near the Mediterranean Sea is an unique environment known for the variety of endemic species. Nevertheless, an alpine ski station situated on the mountain has dramatically affected the landscape, leaving some areas barren. In an effort to restore the vegetation cover, laboratory experiments were conducted with seeds of Genista versicolor Boiss and Reseda complicata Bory, two shrubby plants native to Sierra Nevada. Using different concentrations of two plant growth regulators, Ethrel and N6-benzyladenine, seeds from both species were planted in soil sampled from the alpine ski resort. Surprisingly, both Ethrel and N6-benzyladenine significantly improved seedling establishment. Consequently, seedling pre-treatment with definite plant growth regulators could be a useful approach to revegetation of the Sierra Nevada mountain range.
Destructive procedures for the treatment of nonmalignant pain: a structured literature review
Authors: Cetas Justin S. , Saedi Targol , Burchiel Kim J.
Published: August 2008

Object

Nonmalignant pain has been treated in the past century with ablative, or more appropriately, destructive procedures. Although individual outcomes for these procedures have previously been described in the literature, to the authors' knowledge this is the first comprehensive and systematic review on this topic.

Methods

A US National Library of Medicine PubMed search was conducted for the following ablative procedures: cingulotomy, cordotomy, DREZ (also input as dorsal root entry zone), ganglionectomy, mesencephalotomy, myelotomy, neurotomy, rhizotomy, sympathectomy, thalamotomy, and tractotomy. Articles related to pain resulting from malignancy and those not in peer-reviewed journals were excluded. In reviewing pertinent articles, focus was placed on patient number, outcome, and follow-up.

Results

A total of 146 articles was included in the review. The large majority of studies (131) constituted Class III evidence. Eleven Class I and 4 Class II studies were found, of which nearly all (13 of 15) evaluated radiofrequency rhizotomies for different pain origins, including lumbar facet syndrome, cervical facet pain, and Type I or typical trigeminal neuralgia. Overall, support for ablative procedures for nonmalignant pain is derived almost entirely from Class III evidence; despite a long history of use in neurosurgery, the evidence supporting destructive procedures for benign pain conditions remains limited.

Conclusions

Newly designed prospective standardized studies are required to define surgical indications and outcomes for these procedures, to provide more systematic review, and to advance the field.
Microvascular decompression for hemifacial spasm: long-term results from 114 operations performed without neurophysiological monitoring
Authors: Dannenbaum Mark , Lega Bradley C. , Suki Dima , Harper Richard L. , Yoshor Daniel
Published: August 2008

Object

Microvascular decompression (MVD) of the facial nerve is an effective treatment for hemifacial spasm (HFS), but the procedure is associated with a significant risk of complications such as hearing loss and facial weakness. Many surgeons advocate the use of intraoperative brainstem auditory evoked response (BAER) monitoring in an attempt to improve surgical outcomes. The authors critically assessed a large series of patients with HFS who underwent MVD without neurophysiological monitoring.

Methods

The authors retrospectively identified 114 consecutive patients, with a history of HFS and without a history of HFS surgery, in whom MVD was performed by a single surgeon without the use of neurophysiological monitoring. Postoperative outcomes were determined by reviewing records and through telephone interviews. At least 1 year of postoperative follow-up data were available for 91 of the 114 patients, and the median follow-up duration in all cases was 8 years (range 3 months–23 years). A Kaplan–Meier analysis showed that 86% of the patients were spasm free at 10 years postoperatively.

Results

There were no surgical deaths or major deficits, and complications included 1 case of postoperative deafness, 1 of permanent subtotal hearing loss, and 10 of delayed facial palsy, 2 of which did not completely resolve at last follow-up. The outcomes, rates of hearing loss, and other complications compared well with those reported in studies in which investigators used intraoperative monitoring.

Conclusions

The results suggest that MVD without neurophysiological monitoring is a safe and effective treatment option in patients with HFS. Although BAER monitoring may be a valuable adjunct to surgery at centers experienced with the modality, the absence of intraoperative monitoring should not prevent neurosurgeons from performing MVD in patients with HFS.
Neurovascular compression findings in hemifacial spasm
Authors: Campos-Benitez Mauricio , Kaufmann Anthony M.
Published: August 2008

Object

It is generally accepted that hemifacial spasm (HFS) is caused by pulsatile vascular compression upon the facial nerve root exit zone. This 2–3 mm area, considered synonymous with the Obersteiner–Redlich zone, is a transition zone (TZ) between central and peripheral axonal myelination that is situated at the nerve's detachment from the pons. Further proximally, however, the facial nerve is exposed on the pontine surface and emerges from the pontomedullary sulcus. The incidence and significance of neurovascular compression upon these different segments of the facial nerve in patients with HFS has not been previously reported.

Methods

The nature of neurovascular compression was determined in 115 consecutive patients undergoing their first microvascular decompression (MVD) for HFS. The location of neurovascular compression was categorized to 1 of 4 anatomical portions of the facial nerve: RExP = root exit point; AS = attached segment; RDP = root detachment point that corresponds to the TZ; and CP = distal cisternal portion. The severity of compression was defined as follows: mild = contact without indentation of nerve; moderate = indentation; and severe = deviation of the nerve course. Success in alleviating HFS was documented by telephone interview conducted at least 24 months following MVD surgery.

Results

Neurovascular compression was found in all patients, and the main culprit was the anterior inferior cerebellar artery (in 43%), posterior inferior cerebellar artery (in 31%), vertebral artery (in 23%), or a large vein (in 3%). Multiple compressing vessels were found in 38% of cases. The primary culprit location was at RExP in 10%, AS in 64%, RDP in 22%, and CP in 3%. The severity of compression was mild in 27%, moderate in 61%, and severe in 12%. Failure to alleviate HFS occurred in 9 cases, and was not related to compression location, severity, or vessel type.

Conclusions

The authors observed that culprit neurovascular compression was present in all cases of HFS, but situated at the RDP or Obersteiner–Redlich zone in only one-quarter of cases and rarely on the more distal facial nerve root. Since the majority of culprit compression was found more proximally on the pontine surface or even pontomedullary sulcus origin of the facial nerve, these areas must be effectively visualized to achieve consistent success in performing MVD for HFS.
Increase in cerebral aerobic metabolism by normobaric hyperoxia after traumatic brain injury
Authors: Tisdall Martin M. , Tachtsidis Ilias , Leung Terence S. , Elwell Clare E. , Smith Martin
Published: August 2008

Object

Traumatic brain injury (TBI) is associated with depressed aerobic metabolism and mitochondrial dysfunction. Normobaric hyperoxia (NBH) has been suggested as a treatment for TBI, but studies in humans have produced equivocal results. In this study the authors used brain tissue O2 tension measurement, cerebral microdialysis, and near-infrared spectroscopy to study the effects of NBH after TBI. They investigated the effects on cellular and mitochondrial redox states measured by the brain tissue lactate/pyruvate ratio (LPR) and the change in oxidized cytochrome c oxidase (CCO) concentration, respectively.

Methods

The authors studied 8 adults with TBI within the first 48 hours postinjury. Inspired oxygen percentage at normobaric pressure was increased from baseline to 60% for 60 minutes and then to 100% for 60 minutes before being returned to baseline for 30 minutes.

Results

The results are presented as the median with the interquartile range in parentheses. During the 100% inspired oxygen percentage phase, brain tissue O2 tension increased by 7.2 kPa (range 4.5–9.6 kPa) (p < 0.0001), microdialysate lactate concentration decreased by 0.26 mmol/L (range 0.0–0.45 mmol/L) (p = 0.01), microdialysate LPR decreased by 1.6 (range 1.0–2.3) (p = 0.02), and change in oxidized CCO concentration increased by 0.21 μmol/L (0.13–0.38 μmol/L) (p = 0.0003). There were no significant changes in intracranial pressure or arterial or microdialysate glucose concentration. The change in oxidized CCO concentration correlated with changes in brain tissue O2 tension (rs= 0.57, p = 0.005) and in LPR (rs= −0.53, p = 0.006).

Conclusions

The authors have demonstrated oxidation in cerebral cellular and mitochondrial redox states during NBH in adults with TBI. These findings are consistent with increased aerobic metabolism and suggest that NBH has the potential to improve outcome after TBI. Further studies are warranted.
Examination of the management of traumatic brain injury in the developing and developed world: focus on resource utilization, protocols, and practices that alter outcome
Authors: Harris Odette A. , Bruce Carl A. , Reid Marvin , Cheeks Randolph , Easley Kirk , Surles Monique C. , Pan Yi , Rhoden-Salmon Donnahae , Webster Dwight , Crandon Ivor
Published: August 2008

Object

We evaluated management and outcome of traumatic brain injury (TBI) in a developed country (US) and a developing country (Jamaica).

Methods

Data were collected prospectively at Grady Memorial Hospital (GMH) in the US and at University Hospital of the West Indies (UHWI) and Kingston Public Hospital (KPH) in Jamaica between September 1, 2003, and September 30, 2004.

Results

Complete data were available for 1607 patients. Grady Memorial Hospital had a higher proportion of females (p = 0.003), and patients were older at GMH (p = 0.0009) compared with patients at KPH and UHWI. The most common mode of injury was a motor vehicle accident at KPH and GMH (42 and 66%, respectively) and assaults at UHWI (37%). Grady Memorial Hospital admitted more patients with severe head injuries (25.5%) than KPH (18.5%) and UHWI (14.4%). More CT scans were performed (p < 0.0001) and a higher proportion of patients were admitted to the intensive care unit (p < 0.0001) at GMH. There were no statistically significant differences in median days in the intensive care unit among the 3 hospitals. Patients experienced statistically significant differences in days undergoing ventilation between GMH, KPH, and UHWI (p = 0.004). Intracranial pressure monitoring was performed in 1 patient at KPH, in 6 at UHWI, and in 91 at GMH. There were 174 total deaths, but no statistically significant differences in mortality rates between the 3 sites (p = 0.3). Hospital location and TBI severity were associated with a decreased risk of mortality; patients with severe TBI at GMH had a 53% decrease in the risk of mortality (odds ratio = 0.47, p = 0.04). Patients at GMH had lower mean Glasgow Outcome Scale scores (p < 0.0001) and lower Functional Independence Measure self-feed (p = 0.0003), locomotion (p = 0.04), and verbal scores (p < 0.0001).

Conclusions

Despite the availability of advanced technology and more aggressive neurological support at GMH, the overall mortality rate for TBI was similar at all locations. Patients identified with severe TBI had a significantly decreased risk of mortality if they were treated at GMH compared with those patients treated at hospitals in the developing world.
Terson hemorrhage in patients suffering aneurysmal subarachnoid hemorrhage: predisposing factors and prognostic significance
Authors: Fountas Kostas N. , Kapsalaki Eftychia Z. , Lee Gregory P. , Machinis Theofilos G. , Grigorian Arthur A. , Robinson Joe S. , Vergados Ioannis , Theodosiadis Panagiotis G.
Published: August 2008

Object

The association of vitreous and/or subhyaloid hemorrhage with aneurysmal subarachnoid hemorrhage (SAH) has been frequently identified since the original description by Terson in 1900. In this prospective clinical study the authors examined the actual incidence of Terson hemorrhage in patients suffering aneurysmal SAH, they attempted to identify those parameters that could predispose its development, and they evaluated its prognostic significance in the overall patients' outcome.

Methods

A total of 174 patients suffering aneurysmal SAH were included in this study. The admitting Glasgow Coma Scale scores (GCS), World Federation of Neurological Societies (WFNS) scale scores, Hunt and Hess grades, and Fisher grades were recorded. A careful ophthalmological evaluation was performed in all participants. The exact anatomical locations and the largest diameter of the dome of the ruptured aneurysms were also recorded. Surgical clipping or endovascular coiling was used in 165 patients. Clinical outcome was evaluated at discharge from the hospital by using the Glasgow Outcome Scale and the modified Rankin Scale. Periodic ophthalmological evaluations were performed for 2 years.

Results

In this series, the observed incidence of Terson hemorrhage was 12.1%. Statistical analysis of our data demonstrated that patients with low GCS scores and high WFNS scores, Hunt and Hess grades, and Fisher grades had an increased incidence of Terson hemorrhage. The mortality rate for patients with Terson hemorrhage was 28.6%, whereas that for patients without Terson hemorrhage was 2.0%. Moreover, patients with Terson hemorrhage who survived had significantly worse outcomes than those in patients without Terson hemorrhage.

Conclusions

Terson hemorrhage constitutes a common SAH-associated complication. Its incidence is increased in patients with low GCS and high WFNS scores, and high Hunt and Hess and Fisher grades. Its presence is associated with increased mortality and morbidity rates.
Fibrothorax in adulthood caused by a cerebrospinal fluid shunt in the treatment of hydrocephalus
Authors: Khan Tanveer Ahmed , Khalil-Marzouk Joseph F.
Published: August 2008

Ventriculopleural shunts have been used as an alternative to ventriculoperitoneal shunts in the treatment of hydrocephalus. Although recurrent pleural effusion is a known complication of this procedure, severe fibrothorax requiring decortication has been described only once, in a case involving a child. The authors report a case of a severe fibrothorax with an entrapped lung presenting in an adult patient.
A recurrent cerebral arteriovenous malformation in an adult
Authors: Codd Patrick J. , Mitha Alim P. , Ogilvy Christopher S.
Published: August 2008

Arteriovenous malformations are generally considered to be cured following angiographically proven complete resection. However, rare instances of AVM recurrence despite negative findings on postoperative angiography have been reported in both children and adults. In this paper, the authors present the case of a 33-year-old woman with 2 AVM recurrences. This patient represents the oldest case of recurrent AVM, and the first adult double recurrence reported in the literature. The case is presented, the radiological and surgical features are considered, and the literature on recurrent AVMs is reviewed.
Cerebral vascular responsiveness after experimental traumatic brain injury: the beneficial effects of delayed hypothermia combined with superoxide dismutase administration
Authors: Baranova Anna I. , Wei Enoch P. , Ueda Yuji , Sholley Milton M. , Kontos Hermes A. , Povlishock John T.
Published: August 2008

Object

Traumatic brain injury (TBI) induces cerebral vascular dysfunction reflected in altered responses to vasodilators such as acetylcholine and hypercapnia. It has been demonstrated that the use of either posttraumatic hypothermia or free radical scavengers offered vascular protection when those treatments were delivered early after the injury, losing efficacy when the initiation of either treatment was delayed. Because immediate posttraumatic treatment is not realistic in the clinical setting, the authors undertook this study to investigate whether the combination of delayed hypothermia and the delayed administration of the free radical scavenger superoxide dismutase (SOD) could result in improved vascular protection.

Methods

Male Sprague–Dawley rats were anesthetized and subjected to either an impact-acceleration or sham injury. Animals were treated either with hypothermia (32°C) initiated 60 minutes after TBI, delayed SOD (60 U/ml) applied 90 minutes after TBI, or a combination of delayed hypothermia (32°C) and delayed SOD (60 U/ml) applied 15 minutes prior to the cessation of hypothermia. In this investigation, the diameter of cerebral pial arterioles was measured at rest and then challenged with vasodilator acetylcholine and hypercapnia. Four vessels were assessed per animal prior to injury and then again up to 6 hours after injury.

Results

Delayed SOD treatment did not enhance vascular function, while delayed hypothermia treatment only partially preserved pial vascular function. However, the combination of delayed hypothermia and delayed SOD significantly preserved vascular function after the injury.

Conclusions

The results of these studies demonstrate that delayed hypothermia partially preserves vascular function after TBI, while expanding the therapeutic window over which agents such as SOD can now provide enhanced protection.
Minimally invasive superficial temporal artery to middle cerebral artery bypass through an enlarged bur hole: the use of computed tomography angiography neuronavigation in surgical planning
Authors: Coppens Jeroen R. , Cantando John D. , Abdulrauf Saleem I.
Published: August 2008

The authors describe their minimally invasive technique for performing a superficial temporal artery (STA) to middle cerebral artery (MCA) bypass, which relies on an enlarged bur hole (2–2.5 cm) rather than the standard craniotomy. They perform this procedure in a minimally invasive fashion, using CT angiography for intraoperative neuronavigation as well as for preoperative identification of the donor and recipient vessels and planning of bur hole location. They present 2 cases in which this procedure was used, including one involving a patient with multivessel occlusive disease and significant cerebrovascular hemodynamic compromise in whom they performed the procedure using only local anesthetic and propofol sedation in order to minimize the risk of hypotension associated with the use of general anesthetic agents. A comprehensive literature search revealed no previously published case of an extracranial–intracranial arterial bypass procedure performed in an awake patient.

The authors have adopted the described minimally invasive method for all STA–MCA bypass procedures. The awake setting, however, is reserved for specific indications, primarily patients with severe moyamoya disease, in whom ventilator-related hypocarbia can result in intraoperative ischemia, or patients with multivessel occlusive disease and significant cerebral hemodynamic compromise, in whom general anesthesia–related hypotension can lead to intraoperative ischemia.