bluuebunny/crossref_metadata_2025 huggingface dataset:
Posttraumatic vasospasm: the epidemiology, severity, and time course of an underestimated phenomenon: a prospective study performed in 299 patients
Authors: Oertel Matthias , Boscardin W. John , Obrist Walter D. , Glenn Thomas C. , McArthur David L. , Gravori Tooraj , Lee Jae Hong , Martin Neil A.
Published: May 2009

Object. The purpose of this prospective study was to evaluate the cumulative incidence, duration, and time course of cerebral vasospasm after traumatic brain injury (TBI) in a cohort of 299 patients.

Methods. Transcranial Doppler (TCD) ultrasonography studies of blood flow velocity in the middle cerebral and basilar arteries (VMCA and VBA, respectively) were performed at regular intervals during the first 2 weeks posttrauma in association with 133Xe cerebral blood flow (CBF) measurements. According to current definitions of vasospasm, five different criteria were used to classify the patients: A (VMCA > 120 cm/second); B (VMCA > 120 cm/second and a Lindegaard ratio [LR] > 3); C (spasm index [SI] in the anterior circulation > 3.4); D (VBA > 90 cm/second); and E (SI in the posterior circulation > 2.5). Criteria C and E were considered to represent hemodynamically significant vasospasm. Mixed-effects spline models were used to analyze the data of multiple measurements with an inconsistent sampling rate.

Overall 45.2% of the patients demonstrated at least one criterion for vasospasm. The patients in whom vasospasm developed were significantly younger and had lower Glasgow Coma Scale scores on admission. The normalized cumulative incidences were 36.9 and 36.2% for patients with Criteria A and B, respectively. Hemodynamically significant vasospasm in the anterior circulation (Criterion C) was found in 44.6% of the patients, whereas vasospasm in the BA—Criterion D or E—was found in only 19 and 22.5% of the patients, respectively. The most common day of onset for Criteria A, B, D, and E was postinjury Day 2. The highest risk of developing hemodynamically significant vasospasm in the anterior circulation was found on Day 3. The daily prevalence of vasospasm in patients in the intensive care unit was 30% from postinjury Day 2 to Day 13. Vasospasm resolved after a duration of 5 days in 50% of the patients with Criterion A or B and after a period of 3.5 days in 50% of those patients with Criterion D or E. Hemodynamically significant vasospasm in the anterior circulation resolved after 2.5 days in 50% of the patients. The time course of that vasospasm was primarily determined by a decrease in CBF.

Conclusions. The incidence of vasospasm after TBI is similar to that following aneurysmal subarachnoid hemorrhage. Because vasospasm is a significant event in a high proportion of patients after severe head injury, close TCD and CBF monitoring is recommended for the treatment of such patients.
Use of a simple intraoperative hydrostatic pressure test to assess the relationship between mobility of the ventricular stoma and success of third ventriculostomy
Authors: Kamel Mahmoud Hamdy , Kelleher Michael , Aquilina Kristian , Lim Chris , Caird John , Kaar George
Published: May 2009

Object. Neuroendoscopists often note pulsatility or flabbiness of the floor of the third ventricle during endoscopic third ventriculostomy (ETV) and believe that either is a good indication of the procedure's success. Note, however, that this belief has never been objectively measured or proven in a prospective study. The authors report on a simple test—the hydrostatic test—to assess the mobility of the floor of the third ventricle and confirm adequate ventricular flow. They also analyzed the relationship between a mobile floor (a positive hydrostatic test) and prospective success of ETV.

Methods. During a period of 3 years between July 2001 and July 2004, 30 ETVs for obstructive hydrocephalus were performed in 22 male and eight female patients. Once the stoma had been created, the irrigating Ringer lactate solution was set at a 30-cm height from the external auditory meatus, and the irrigation valve was opened while the other ports on the endoscope were closed. The ventricular floor ballooned downward and stabilized. The irrigation valve was then closed and ports of the endoscope were opened. The magnitude of the upward displacement of the floor was then assessed. Funneling of the stoma was deemed to be a good indicator of floor mobility, adequate flow, and a positive hydrostatic test. All endoscopic procedures were recorded using digital video and recordings were subsequently assessed separately by two blinded experienced neuroendoscopists. Patients underwent prospective clinical follow up during a mean period of 11.2 months (range 1 month–3 years), computerized tomography and/or magnetic resonance imaging studies of the brain, and measurements of cerebrospinal fluid pressure through a ventricular reservoir when present. Failure of ETV was defined as the subsequent need for shunt implantation. The overall success rate of the ETV was 70% and varied from 86.9% in patients with a mobile stoma and a positive hydrostatic test to only 14.2% in patients with a poorly mobile floor and a negative test (p < 0.05). The positive predictive value of the hydrostatic test was 86.9%, negative predictive value 85.7%, sensitivity 95.2%, and specificity 66.6%.

Conclusions. The authors concluded that the hydrostatic test is an easy, brief test. A positive test result confirms a mobile ventricular floor and adequate flow through the created ventriculostomy. Mobility of the stoma is an important predictor of ETV success provided that there is no obstruction at the level of the arachnoid granulations or venous outflow. A thin, redundant, mobile third ventricle floor indicates a longstanding pressure differential between the third ventricle and the basal cisterns, which is a crucial factor for ETV success. A positive hydrostatic test may avert the need to insert a ventricular reservoir, thus avoiding associated risks of infection.
Entrapment neuropathy of the optic nerve due to hyperostosis associated with congenital anemia
Authors: Baba Takeo , Minamida Yoshihiro , Mikami Takeshi , Koyanagi Izumi , Houkin Kiyohiro
Published: May 2009

✓ The authors report on the case of a 14-year-old boy who presented with bilateral visual impairment due to optic canal stenosis caused by hyperplasia of the bone marrow arising from anemia. The patient had hereditary hemolytic anemia with unstable hemoglobin of the Christchurch type. This congenital form of anemia caused hyperplasia of the bone marrow as well as hyperostosis of the entire calvarial bone, which in turn led to optic canal stenosis. The patient underwent surgical decompression of the optic canal, resulting in significant improvement in visual acuity. Pathological findings in the calvarial bone indicated hypertrophic bone marrow with no other specific features such as neoplastic pattern or fibrous dysplasia. With the exception of objective hearing impairment, no other significant cranial neuropathy has been detected thus far.

On reviewing the published literature, this case was found to be the first in which hyperostosis due to congenital anemia resulted in symptomatic entrapment neuropathy of the optic nerve. The authors concluded that surgical decompression effectively improves visual acuity.
Deep brain stimulation in movement disorders: stereotactic coregistration of two-dimensional electrical field modeling and magnetic resonance imaging
Authors: Hemm Simone , Mennessier Gérard , Vayssiere Nathalie , Cif Laura , El Fertit Hassan , Coubes Philippe
Published: May 2009

Object. Adjusting electrical parameters used in deep brain stimulation (DBS) for dystonia remains time consuming and is currently based on clinical observation alone. The goal of this study was to visualize electrical parameters around the electrode, to correlate these parameters with the anatomy of the globus pallidus internus (GPI), and to study the relationship between the volume of stimulated tissue and the electrical parameter settings.

Methods. The authors developed a computer-assisted methodological model for visualizing electrical parameters (the isopotential and the isoelectric field magnitude), with reference to the stereotactic target, for different stimulation settings (monopolar and bipolar) applied during DBS. Electrical field values were correlated with the anatomy of the GPI, which was determined by performing stereotactic magnetic resonance imaging in one reference patient.

By using this method it is possible to compare potential and electrical field distributions for different stimulation modes. In monopolar and bipolar stimulation, the shape and distribution of the potential and electrical field are different and depend on the stimulation voltage. Distributions visualized for patient-specific parameters can be subsequently correlated with anatomical information. The application of this method to one patient demonstrated that the 0.2-V/mm isofield line fits best with the lateral GPI borders at the level of the stimulated contacts.

Conclusions. The electrical field is a crucial parameter because it is assumed to be responsible for triggering action potentials. Electrical field visualization allows the calculation of the stimulated volume for a given isoline. Its application to an entire series of patients may help determine a threshold for obtaining a therapeutic effect, which is currently unknown, and consequently may aid in optimizing parameter settings in individual patients.
Attenuation of fluctuating striatal synaptic dopamine levels in patients with Parkinson disease in response to subthalamic nucleus stimulation: a positron emission tomography study
Authors: Nimura Taro , Yamaguchi Keiichiro , Ando Tadashi , Shibuya Satoshi , Oikawa Takanori , Nakagawa Atsuhiro , Shirane Reizo , Itoh Masatoshi , Tominaga Teiji
Published: May 2009

Object. The “wearing-off” phenomenon often hampers the treatment of Parkinson disease (PD). Although deep brain stimulation (DBS) of the subthalamic nucleus (STN) is known to ameliorate the wearing-off phenomenon, the mechanism by which it does this remains unclear. As part of an inquiry into the mechanism of STN DBS, the authors measured synaptic dopamine levels in the striatum by performing positron emission tomography (PET) with [11C]raclopride.

Methods. Three patients with PD who were experiencing the wearing-off phenomenon underwent PET scanning before and after DBS of the STN. The clinical features in these patients were evaluated by applying the Hoehn and Yahr, United Parkinson's Disease Rating, and Schwab and England Activities of Daily Living Scales. Before and after surgery, PET scans were obtained using [11C]raclopride prior to and 1 hour following an oral administration of levodopa. Regions of interest for the [11C]raclopride binding potential (RacloBP) were set in the bilateral putamen and the caudate nucleus.

All clinical scores were dramatically improved postoperatively. Deep brain stimulation of the STN reduced the baseline RacloBP in both the putamen and caudate nucleus, but the differences between the pre- and postoperative levels were insignificant. Before DBS of the STN, the levodopa administration significantly reduced RacloBP in the putamen (p < 0.0001). Postoperatively the drug-induced reduction in RacloBP became statistically insignificant. The drug-induced increase in synaptic dopamine concentrations in the putamen preoperatively was estimated to be approximately four times higher than that after surgery (p < 0.01). The drug-induced RacloBP change in the caudate nucleus was similar to that in the putamen, although the magnitude of the change was lower (p < 0.005). The drug-induced increase in the caudate nucleus was also reduced postoperatively (p < 0.05).

Conclusions. Deep brain stimulation of the STN induces the stabilization of synaptic dopamine concentrations in the striatum and may attribute to the alleviation of levodopa-related motor fluctuations.
Relative importance of hypertension compared with hypervolemia for increasing cerebral oxygenation in patients with cerebral vasospasm after subarachnoid hemorrhage
Authors: Raabe Andreas , Beck Jügen , Keller Mike , Vatter Hartmuth , Zimmermann Michael , Seifert Volker
Published: May 2009

Object. Hypervolemia and hypertension therapy is routinely used for prophylaxis and treatment of symptomatic cerebral vasospasm at many institutions. Nevertheless, there is an ongoing debate about the preferred modality (hypervolemia, hypertension, or both), the degree of therapy (moderate or aggressive), and the risk or benefit of hypervolemia, moderate hypertension, and aggressive hypertension in patients following subarachnoid hemorrhage.

Methods. Monitoring data and patient charts for 45 patients were retrospectively searched to identify periods of hypervolemia, moderate hypertension, or aggressive hypertension. Measurements of central venous pressure, fluid input, urine output, arterial blood pressure, intracranial pressure, and oxygen partial pressure (PO2) in the brain tissue were extracted from periods ranging from 1 hour to 24 hours. For these periods, the change in brain tissue PO2 and the incidence of complications were analyzed.

During the 55 periods of moderate hypertension, an increase in brain tissue PO2 was found in 50 cases (90%), with complications occurring in three patients (8%). During the 25 periods of hypervolemia, an increase in brain oxygenation was found during three intervals (12%), with complications occurring in nine patients (53%). During the 10 periods of aggressive hypervolemic hypertension, an increase in brain oxygenation was found during six of the intervals (60%), with complications in five patients (50%).

Conclusions. When hypervolemia treatment is applied as in this study, it may be associated with increased risks. Note, however, that further studies are needed to determine the role of this therapeutic modality in the care of patients with cerebral vasospasm. In poor-grade patients, moderate hypertension (cerebral perfusion pressure 80–120 mm Hg) in a normovolemic, hemodiluted patient is an effective method of improving cerebral oxygenation and is associated with a lower complication rate compared with hypervolemia or aggressive hypertension therapy.
Angiographic and clinical results in 316 coil-treated basilar artery bifurcation aneurysms
Authors: Henkes Hans , Fischer Sebastian , Mariushi Wagner , Weber Werner , Liebig Thomas , Miloslavski Elina , Brew Stefan , Kühne Dietmar
Published: May 2009

Object. The aim of this study was to analyze the effect of the endovascular treatment of basilar artery (BA) bifurcation aneurysms and to compare the results with those published by other neuroendovascular teams.

Methods. The authors performed a retrospective analysis of 316 aneurysms of the BA bifurcation that had been treated using endovascular coil occlusion between November 6, 1992, and February 12, 2005. After the initial embolization procedure, a 90 to 100% occlusion rate was achieved in 86% of the aneurysms. No complication was evident in 80% of the lesions, although periprocedural aneurysm rupture (3.2%) and thromboembolic events (12.3%) were the most frequent complications. Clinical outcome according to the Glasgow Outcome Scale (GOS) was a score of 5 or 4 in 77%, 3 in 11%, 2 in 5%, and 1 in 7% of patients. Initial follow-up angiography studies were obtained in 56% of patients at a mean of 19 months posttreatment and demonstrated a 90 to 100% occlusion rate in 70%. No recurrence was seen on 65% of the aneurysms. Coil compaction was evident on 24% of the follow-up angiograms.

A second treatment was performed on 48 aneurysms (15%) a mean of 27 months after the first therapeutic session and resulted in 90 to 100% occlusion in 83% of the lesions. Complications were encountered in 19% of the aneurysms. Rupture did not occur during any of the procedures. Clinical outcome was rated as GOS Score 5 or 4 in 83% of the patients and Grade 3 in 17%.

During a cumulative clinical follow up of 821 years in 237 patients, 182 patients (81%) were independent (GOS Score 5 or 4), 33 (14%) were dependent (GOS Score 3), eight (3%) were in a vegetative state, and two (1%) had died. Clinical outcome was significantly worse after previous aneurysm rupture and following procedural complications.

Conclusions. These results are within the range of published data for coil treatment of BA tip aneurysms and confirm both the safety and efficacy of this endovascular treatment method.
Modified boron neutron capture therapy for malignant gliomas performed using epithermal neutron and two boron compounds with different accumulation mechanisms: an efficacy study based on findings on neuroimages
Authors: Miyatake Shin-Ichi , Kawabata Shinji , Kajimoto Yoshinaga , Aoki Atsushi , Yokoyama Kunio , Yamada Makoto , Kuroiwa Toshihiko , Tsuji Motomu , Imahori Yoshio , Kirihata Mitsunori , Sakurai Yoshinori , Masunaga Shin-Ichiro , Nagata Kenji , Maruhashi Akira , Ono Koji
Published: May 2009

Object. To improve the effectiveness of boron neutron capture therapy (BNCT) for malignant gliomas, the authors used epithermal rather than thermal neutrons for deep penetration and two boron compounds—sodium borocaptate (BSH) and boronophenylalanine (BPA)—with different accumulation mechanisms to increase the boron level in tumors while compensating for each other's faults.

Methods. Thirteen patients, 10 of whom harbored a glioblastoma multiforme (GBM), one a gliosarcoma, one an anaplastic astrocytoma, and one an anaplastic oligoastrocytoma, were treated using this modified BNCT between January 2002 and December 2003. Postoperatively, neuroimaging revealed that only one patient with a GBM had no lesion enhancement postoperatively. The patients underwent 18F-BPA positron emission tomography, if available, to assess the accumulation and distribution of BPA before neutron radiotherapy. The neutron fluence rate was estimated using the Simulation Environments for Radiotherapy Applications dose-planning system before irradiation. The patients' volume assessments were performed using magnetic resonance (MR) imaging or computerized tomography (CT) scanning. Improvements in the disease as seen on neuroimages were assessed between 2 and 7 days after irradiation to determine the initial effects of BNCT; its maximal effects were also analyzed on serial neuroimages.

The mean tumor volume before BNCT was 42.3 cm3. Regardless of the pre-BNCT tumor volume, in every patient harboring an assessable lesion, improvements on MR or CT images were recognized both at the initial assessment (range of volume reduction rate 17.4–71%, mean rate 46.4%) and at follow-up assessments (range of volume reduction rates 30.3–87.6%, mean rate 58.5%). More than 50% of the contrast-enhanced lesions disappeared in eight of the 12 patients during the follow-up period.

Conclusions. This modified BNCT produced a good improvement in malignant gliomas, as seen on neuroimages.
A Possible Mechanism for Evading Temperature Quantum Decoherence in Living Matter by Feshbach Resonance
Authors: Poccia Nicola , Ricci Alessandro , Innocenti Davide , Bianconi Antonio
Published: May 2009

A new possible scenario for the origin of the molecular collective behaviour associated with the emergence of living matter is presented. We propose that the transition from a non-living to a living cell could be mapped to a quantum transition to a coherent entanglement of condensates, like in a multigap BCS superconductor. Here the decoherence-evading qualities at high temperature are based on the Feshbach resonance that has been recently proposed as the driving mechanism for high Tc superconductors. Finally we discuss how the proximity to a particular critical point is relevant to the emergence of coherence in the living cell.
Characterization and Accelerated Ageing of UHMWPE Used in Orthopedic Prosthesis by Peroxide
Authors: Rocha Magda , Mansur Alexandra , Mansur Herman
Published: May 2009

Ultra-high molecular weight polyethylene (UHMWPE) has been the most commonly used bearing material in total joint arthroplasty. Wear and oxidation fatigue resistance of UHMWPE are regarded as two important mechanical properties to extend the longevity of knee prostheses. Though accelerated in vitro protocols have been developed to test the relative oxidation resistance of various types of UHMWPE, its mechanism is not accurately understood yet. Thus, in the present study an accelerated ageing of UHMWPE in hydrogen peroxide solution was performed and relative oxidation was extensively characterized by Fourier Transformed Infrared Spectroscopy (FTIR) spectroscopy and the morphological changes were analyzed by Scanning Electron Microscopy (SEM). Different chemical groups of UHMWPE associated with the degradation reaction were monitored for over 120 days in order to evaluate the possible oxidation mechanism(s) which may have occurred. The results have provided strong evidence that the oxidation mechanism is rather complex, and two stages with their own particular first-order kinetics reaction patterns have been clearly identified. Furthermore, hydrogen peroxide has proven to be an efficient oxidative medium to accelerate ageing of UHMWPE.
Micro- and Nanoscale Hydrogel Systems for Drug Delivery and Tissue Engineering
Authors: Schwall Christine  T. , Banerjee Ipsita  A.
Published: May 2009

The pursuit for targeted drug delivery systems has led to the development of highly improved biomaterials with enhanced biocompatibility and biodegradability properties. Micro- and nanoscale components of hydrogels prepared from both natural and artificial components have been gaining significant importance due to their potential uses in cell based therapies, tissue engineering, liquid micro-lenses, cancer therapy, and drug delivery. In this review some of the recent methodologies used in the preparation of a number of synthetic hydrogels such as poly(N-isopropylacrylamide) (pNIPAm), poly(ethylene glycol) (PEG), poly(ethylene oxide) (PEO), polyvinyl alcohol methylacrylate co-polymers (PVA-MA) and polylactic acid (PLA), as well as some of the natural hydrogels and their applications have been discussed in detail.
Deployment Design of Wireless Sensor Network for Simple Multi-Point Surveillance of a Moving Target
Authors: Tsukamoto Kazuya , Ueda Hirofumi , Tamura Hitomi , Kawahara Kenji , Oie Yuji
Published: May 2009

In this paper, we focus on the problem of tracking a moving target in a wireless sensor network (WSN), in which the capability of each sensor is relatively limited, to construct large-scale WSNs at a reasonable cost. We first propose two simple multi-point surveillance schemes for a moving target in a WSN and demonstrate that one of the schemes can achieve high tracking probability with low power consumption. In addition, we examine the relationship between tracking probability and sensor density through simulations, and then derive an approximate expression representing the relationship. As the results, we present guidelines for sensor density, tracking probability, and the number of monitoring sensors that satisfy a variety of application demands.
Monitoring Animal Behaviour and Environmental Interactions Using Wireless Sensor Networks, GPS Collars and Satellite Remote Sensing
Authors: Handcock Rebecca N. , Swain Dave L. , Bishop-Hurley Greg J. , Patison Kym P. , Wark Tim , Valencia Philip , Corke Peter , O’Neill Christopher J.
Published: May 2009

Remote monitoring of animal behaviour in the environment can assist in managing both the animal and its environmental impact. GPS collars which record animal locations with high temporal frequency allow researchers to monitor both animal behaviour and interactions with the environment. These ground-based sensors can be combined with remotely-sensed satellite images to understand animal-landscape interactions. The key to combining these technologies is communication methods such as wireless sensor networks (WSNs). We explore this concept using a case-study from an extensive cattle enterprise in northern Australia and demonstrate the potential for combining GPS collars and satellite images in a WSN to monitor behavioural preferences and social behaviour of cattle.
Evolution of autonomous selfing accompanies increased specialization in the pollination system of Schizanthus (Solanaceae)
Authors: Pérez Fernanda , Arroyo Mary T. K , Armesto Juan J.
Published: May 2009

The co‐occurrence of elaborate flowers visited by specific groups of pollinators and capacity for autonomous selfing in the same plant species has puzzled evolutionary biologists since the time of Charles Darwin. To examine whether autonomous selfing and floral specialization evolved in association, we quantified the autofertility level (AFI) in nine Schizanthus species characterized by a wide range of pollination specialization, revealing AFI values of 0.02 to complete selfing. An independent contrasts analysis conducted on AFIs and number of functional pollinator groups showed that autonomous selfing evolved from an ancestral outcrossing system as plants became increasingly specialized (r = –0.82). To assess whether autonomous selfing together with specialization acts as a reproductive assurance mechanism, we estimated spatial and interannual variation in fruit set due to pollinator failure in two closely related high Andean Schizanthus species differing in their specialization levels. Variation in pollinator failure rate was more pronounced and autonomous selfing increased fruit production over biotically assisted pollination in the more specialized species. Our study suggests that specialized pollination deems species more vulnerable to pollinator fluctuation thus promoting the evolution of delayed autonomous selfing.
Amniotic Fluid Embolism Complicated by Paradoxical Embolism and Disseminated Intravascular Coagulation
Authors: Kumar Sumeet , Wong Glenn , Maysky Michael , Shulman Mark , Olenchock Stephen , Falzon-Kirby Maria , Oo Thein H.
Published: May 2009

Amniotic fluid embolism is a rare syndrome with potentially lethal outcomes. Complications include cardiorespiratory failure, disseminated intra-vascular coagulation, seizures, neurological deficits, and death. A 34-year-old woman had amniotic fluid embolism complicated by paradoxical embolism and disseminated intravascular coagulation. Emergency cesarean section followed by cardiopulmonary bypass with removal of the clot from the atria and closure of the patent foramen ovale was performed, resulting in a good outcome for both the mother and the baby. Subsequent treatment with anticoagulants for 6 months was recommended. A literature review revealed that this clinical scenario is rare but can be successfully managed by cardiopulmonary bypass and thromboembolectomy. Data on guidelines for the use of anticoagulation in this situation are limited.
Silylated Melamine and Cyanuric Acid as Precursors for Imprinted and Hybrid Silica Materials with Molecular Recognition Properties
Authors: Arrachart Guilhem , Carcel Carole , Trens Philippe , Moreau Jöel J. E. , Wong Chi Man Michel
Published: May 2009

Imprinted materials: Monosilylated derivatives of melamine and cyanuric acid are used in the preparation of hybrid silica. The assembly of the melamine and cyanuric acid moieties through molecular recognition properties is the key factor in building a bridged silsesquioxane and an imprinted hybrid silica (see picture).

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Two monotrialkoxysilylated compounds that consist of complementary fragments of melamine (M) and cyanuric acid (CA) have been synthesised. The molecular recognition properties of the M and CA fragments through complementary hydrogen bonds (DAD and ADA; D=donor, A=acceptor) are the key factor used to direct the formation of hybrid silica materials by using a sol–gel process. These materials were synthesised following two methods: First, an organo‐bridged silsesquioxane was obtained by the hydrolysis of the two complementary monotrialkoxysilylated melamine and cyanuric acid derivatives, with fluoride ions as a catalyst. The hydrogen‐bonding interactions between the two organic fragments are responsible for the formation of the bridging unit. The transcription of the assembly into the hybrid material was characterised and evidenced by solid‐state NMR (29Si, 13C) and FTIR spectroscopic experiments. Second, the molecular recognition was exploited to synthesise an imprinted hybrid silica. This material was prepared by co‐condensation of tetraethyl orthosilicate (TEOS) with the monosilylated cyanuric acid derivative (CA) templated by nonsilylated melamine. The melamine template was completely removed by treating the solid material with hydrochloric acid. The reintroduction of the template was performed by treating the resulting material with an aqueous suspension of melamine. These steps were monitored and analysed by several techniques, such as solid‐state NMR (29Si, 13C) and FTIR spectroscopic analysis and nitrogen adsorption–desorption isotherms.
Construction of Nitrogen‐Containing Heterocycles by CH Bond Functionalization
Authors: Thansandote Praew , Lautens Mark
Published: May 2009

Bringing synthesis into the 21st century! How can nitrogen heterocycles be synthesized today? An overview of modern methods for nitrogen‐heterocycle formation is given. Chemists can now use readily available materials combined with CH bond functionalization to prepare common nitrogen heterocycles.

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Nitrogen heterocycles are abundant in natural products and pharmaceuticals. An emerging interest among synthetic chemists is to use CH functionalization to construct the nitrogen‐containing core of these heterocycles. The following article will provide a brief overview of this concept with respect to the type of CH bond functionalized.
Molecular mechanisms of mechanosensing in muscle development
Authors: Jani Klodiana , Schöck Frieder
Published: May 2009

Mechanical forces are crucial to muscle development and function, but the mechanisms by which forces are sensed and transduced remain elusive. Evidence implicates the sarcolemmal lattice of integrin adhesion and the Z‐disk components of the contractile machinery in such processes. These mechanosensory devices report changes in force to other cellular compartments by self‐remodeling. Here we explore how their structural and functional properties integrate to regulate muscle development and maintenance. Developmental Dynamics 238:1526–1534, 2009. © 2009 Wiley‐Liss, Inc.
Algorithms for connected component labeling based on quadtrees
Authors: Aizawa Kunio , Tanaka Shojiro , Motomura Koyo , Kadowaki Ryosuke
Published: May 2009

An algorithm of linear time complexity is presented to label connected components of a binary image by a quadtree. For a given node, the search for all adjacent nodes is carried out inO(1) (i.e., constant time complexity for the worst case) using our formerly presented algorithm in (Aizawa et al., 3rd International Symposium on Communications, Control, and Signal Processing,2008, 505–510), whereas it explores all possible adjacencies for each node in a usual way. Then during the process of tree formulation in the search, all equivalent relations of labels are stored as lists. Time complexity of the algorithm isO(B+W) for the worst case and its auxiliary space is no more thanO(B), whereBandWcorrespond to the number of leaf nodes in a quadtree representing black and white quadrants, respectively. Empirical tests of the algorithm are employed in comparison with another linear time connected component labeling algorithm based on top‐down quadtree traversal algorithm (Samet, IEEE Trans Pattern Anal Mach Intell PAMI‐7 (1985), 94–98), as well as traditional row‐by‐row scanning algorithm using linear time Union‐Find (Fiorio and Gustedt, Theor Comput Sci 154 (1996), 165–181). Our algorithm has shown the best performance in large images. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 158–166, 2009.
A bioartificial surgical patch from multilayered human amniotic membrane—In vivo investigations in a rat model
Authors: Kesting Marco Rainer , Wolff Klaus‐Dietrich , Mücke Thomas , Demtroeder Cedric , Kreutzer Kilian , Schulte Matthias , Jacobsen Frank , Hirsch Tobias , Loeffelbein Denys John , Steinstraesser Lars
Published: May 2009

The study was performed to evaluate the suitability of glycerol‐cryopreserved human amniotic membrane (HAM) as a surgical patch, far from its common use in ophthalmic surgery. In vivo experiments in rat models were performed to study the degradation patterns, biocompatibility, postoperative tissue formation and its suitability for abdominal wall closure. Degradation and thickness of the membranes were assessed over a period of 60 days after subdermal implantation of monolayer and multilayer HAM in 96 immunocompetent and immunosuppressed rats. The tissue response was mild, and histological analysis evaluated that multilayer application and immunosuppression prolonged graft survival significantly. In a second rat model, another 18 animals were monitored over a period of 28 days after abdominal wall reconstruction with multilayered HAM. Polypropylene mesh (Prolene®) and polyglactin910/polydioxanon patches (Ethisorb®) served as controls. Gross examination and histological analysis proved that multilayer HAM was a sufficient material for abdominal wall closure in comparison with the polypropylene mesh and was superior to the polyglactin910/polydioxanon patch. Additionally, significantly reduced postoperative intraabdominal adhesions were observed when compared to the polyglactin910/polydioxanon patch. This study demonstrates that HAM is a biocompatible, resorbable surgical patch in a rat xenotransplantation model and serves as a mechanically sufficient material for abdominal wall closure in a small animal model. These findings are encouraging and justify further research for the use of cryopreserved human amniotic membrane in soft tissue repair. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
An overview of distal tephrochronology in northern Europe during the last 1000 years
Authors: Wastegård Stefan , Davies Siwan M.
Published: May 2009

Several tephra layers from the last millennium have been identified in distal peat and lake sediment sequences in northern Europe, forming a framework of volcanic events of great value for palaeoenvironmental investigations. Most of the tephras within this framework have an origin in Iceland, but distal layers from Jan Mayen have also been identified. The predominant transport pathway, in an easterly–southeasterly direction, has led to the deposition of these tephras in a number of terrestrial deposits in northern Europe. Ash from silicic eruptions (>63% SiO2) dominate at these sites, even though many of the documentary records in distal areas report tephra fall from several basaltic eruptions. Here we provide an overview of the distribution, shard concentration and geochemistry of these tephras to highlight the most important isochrones for addressing key dating issues. In particular, three horizons – Hekla‐1 (AD 1104), Öræfajökull (AD 1362) and Askja (AD 1875) – are found at a number of different locations in northern Europe and as such are valuable tie‐points for improving and validating chronological models and for synchronisation of records spanning the last 1000 years. In addition, we present new data identifying tephra from the Grímsvötn volcanic system within the Lomonosovfonna ice cap on Svalbard, demonstrating that some tephras have been transported 2000 km to as far north as 79° N along a northeasterly trajectory. This discovery highlights the potential for utilising tephrochronology as a correlation tool for palaeoarchives located in more northerly areas and the complex nature of fall‐out from different eruptions. Copyright © 2009 John Wiley & Sons, Ltd.
On wafer‐scaled GaAs HEMTs: Direct and robust small signal modeling up to 50 GHz
Authors: Caddemi Alina , Crupi Giovanni , Macchiarella Alessio
Published: May 2009

This article is aimed at extracting an accurate multibias small signal equivalent circuit for on‐wafer microwave HEMTs, which are based on AlGaAs/GaAs heterostructure. The main advantage of the on‐wafer characterization consists of having the possibility to determine the real microwave performance of the transistors, since the inclusion of additional parasitic effects, such as in the case of the packaging and wire bonding, are avoided. The presented small signal modeling technique is direct. As a matter of fact, the equivalent circuit elements are extracted from scattering parameter measurements by using only analytical formulas, without any optimization procedures. The validity of the obtained circuit models is successfully verified by comparing simulated and measured data of scaled GaAs HEMTs up to 50 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1958–1963, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24492
In vitro generation of murine myeloid dendritic cells from CD34‐positive precursors
Authors: Stephen Tom‐Li , Harms Fabian , Fabri Mario , Flenner Eva , Bessler Martina , Hafke Helena , Meemboor Sonja , Kalka Christoph , Kalka‐Moll Wiltrud
Published: May 2009

Dendritic cells (DCs) link the innate and adaptive immune system. Currently, murine DCs for cell biology investigations are developed from MHC class II‐negative bone marrow (BM) precursor cells, non‐depleted BM cells or BM monocytes in the presence of granulocyte‐macrophage colony‐stimulating factor (GM‐CSF). Here we demonstrate an isolation procedure of functionally intact myeloid CD11c+ CD11b+ DCs derived from murine CD34‐positive precursors. DCs derived from CD34+ cells show functional internalization, maturation, cytokine secretion, MHC‐restricted antigen presentation, and MHCII retrograde transport of antigens from the lysosomes to the cell surface. In comparison to the established method, the advantages of this isolation procedure are a shorter cultivation period, a superior transfection efficiency, the yield of a purer and more homogeneous population of immature DCs, and less consumption of cell culture medium and GM‐CSF. The new isolation procedure and the functional quality of CD34+ cell‐derived murine myeloid DCs make them ideally suited for immunology and cell biology studies.
Sub‐mitogenic phorbol myristate acetate co‐stimulation rescues the PHA‐induced activation of both naïve and memory T cells cultured in the rotating‐wall vessel bioreactor
Authors: Simons Donald M. , Gardner Elizabeth M. , Lelkes Peter I.
Published: May 2009

T lymphocytes are unresponsive to T cell receptor (TCR) stimulation during culture in spaceflight or ground‐based microgravity analogs such as the rotating‐wall vessel (RWV) bioreactor. The TCR‐induced activation of a subset of T cells can be rescued in the RWV by co‐stimulation with sub‐mitogenic doses of phorbol ester (PMA). We report that PMA co‐stimulation of primary human T cells cultured in the RWV rescues the phytohemagglutinin (PHA)‐induced activation of the CD8+ and CD4+ T cell subsets as well as naïve and memory CD4+ T cells. Importantly, T cells activated in the RWV by PHA + PMA contained these subsets in proportions strikingly similar to control cultures activated with PHA alone. The data indicate that rescuing T cell activation with PMA co‐stimulation does not significantly perturb the heterogeneity of the responding cells, and represent an important proof of principle for the design of immune‐boosting agents for use in spaceflight.
Functional dissection of the intramolecular Src homology 3‐guanylate kinase domain coupling in voltage‐gated Ca2+ channel β‐subunits
Authors: Chen Yu-hang , He Lin-ling , Buchanan Douglas R. , Zhang Yun , Fitzmaurice Aileen , Yang Jian
Published: May 2009

The β‐subunit of voltage‐gated Ca2+ channels is essential for trafficking the channels to the plasma membrane and regulating their gating. It contains a Src homology 3 (SH3) domain and a guanylate kinase (GK) domain, which interact intramolecularly. We investigated the structural underpinnings of this intramolecular coupling and found that in addition to a previously described SH3 domain β strand, two structural elements are crucial for maintaining a strong and yet potentially modifiable SH3–GK intramolecular coupling: an intrinsically weak SH3–GK interface and a direct connection of the SH3 and GK domains. Alterations of these elements uncouple the two functions of the β‐subunit, degrading its ability to regulate gating while leaving its chaperone effect intact.
Structural determinants of product specificity of sucrose isomerases
Authors: Ravaud Stéphanie , Robert Xavier , Watzlawick Hildegard , Haser Richard , Mattes Ralf , Aghajari Nushin
Published: May 2009

The healthy sweetener isomaltulose is industrially produced from the conversion of sucrose by the sucrose isomerase SmuA from Protaminobacter rubrum. Crystal structures of SmuA in native and deoxynojirimycin complexed forms completed with modeling studies unravel the characteristics of the isomaltulose synthases catalytic pocket and their substrate binding mode. Comparison with the trehalulose synthase MutB highlights the role of Arg298 and Arg306 active site residues and surface charges in controlling product specificity of sucrose isomerases (isomaltulose versus trehalulose). The results provide a rationale for the specific design of optimized enzymes.
Phosphoglycerate mutase in mammalian striated muscles: Subcellular localization and binding partners
Authors: Kowalski Wojciech , Gizak Agnieszka , Rakus Darek
Published: May 2009

MINT‐7034028: PGM (uniprotkb:P16290) physically interacts (MI:0218) with lactate dehydrogenase B (uniprotkb:P42123), lactate dehydrogenase A (uniprotkb:P04642), G3PDH (uniprotkb:P04797), aldolase (uniprotkb:P05065), Creatine kinase (uniprotkb:P07335), phPhosphoglycerate kinase (uniprotkb:P16617) and Enolase (uniprotkb:P04764) by pull down (MI:0096)
Glimpses of the molecular mechanisms of β2‐microglobulin fibril formation in vitro: Aggregation on a complex energy landscape
Authors: Platt Geoffrey W. , Radford Sheena E.
Published: May 2009

β2‐microglobulin (β2m) is a 99‐residue protein that aggregates to form amyloid fibrils in dialysis‐related amyloidosis. The protein provides a powerful model for exploration of the structural molecular mechanisms of fibril formation from a full‐length protein in vitro. Fibrils have been assembled from β2m under both low pH conditions, where the precursor is disordered, and at neutral pH where the protein is initially natively folded. Here we discuss the roles of sequence and structure in amyloid formation, the current understanding of the structural mechanisms of the early stages of aggregation of β2m at both low and neutral pH, and the common and distinct features of these assembly pathways.
Arabidopsis thaliana expresses a second functional flavonol synthase
Authors: Preuß Anja , Stracke Ralf , Weisshaar Bernd , Hillebrecht Alexander , Matern Ulrich , Martens Stefan
Published: May 2009

Arabidopsis thaliana L. produces flavonoid pigments, i.e. flavonols, anthocyanidins and proanthocyanidins, from dihydroflavonol substrates. A small family of putative flavonol synthase (FLS) genes had been recognized in Arabidopsis, and functional activity was attributed only to FLS1. Nevertheless, other FLS activities must be present, because A. thaliana fls1 mutants still accumulate significant amounts of flavonols. The recombinant FLSs and leucoanthocyanidin dioxygenase (LDOX) proteins were therefore examined for their enzyme activities, which led to the identification of FLS3 as a second active FLS. This enzyme is therefore likely responsible for the formation of flavonols in the ldox/fls1‐2 double mutant. These double mutant and biochemical data demonstrate for the first time that LDOX is capable of catalyzing the in planta formation of flavonols.
IQGAPs in cancer: A family of scaffold proteins underlying tumorigenesis
Authors: White Colin D. , Brown Matthew D. , Sacks David B.
Published: May 2009

The IQGAP family comprises three proteins in humans. The best characterized is IQGAP1, which participates in protein–protein interactions and integrates diverse signaling pathways. IQGAP2 and IQGAP3 harbor all the domains identified in IQGAP1, but their biological roles are poorly defined. Proteins that bind IQGAP1 include Cdc42 and Rac1, E‐cadherin, β‐catenin, calmodulin and components of the mitogen‐activated protein kinase pathway, all of which are involved in cancer. Here, we summarize the biological functions of IQGAPs that may contribute to neoplasia. Additionally, we review published data which implicate IQGAPs in cancer and tumorigenesis. The cumulative evidence suggests IQGAP1 is an oncogene while IQGAP2 may be a tumor suppressor.
Confidential inquiries into maternal deaths: Modifications and adaptations in Ghana and Indonesia
Authors: Hussein Julia , D'Ambruoso Lucia , Armar‐Klemesu Margaret , Achadi Endang , Arhinful Daniel , Izati Yulia , Ansong‐Tornui Janet
Published: May 2009

Objective

Factors contributing to the limited use of confidential inquiries into maternal deaths include the negative focus and demotivating effect of such inquiries, perceptions of unavailability of sufficient documentation of events, and lack of time and resources. To ascertain whether these problems can be overcome, variations to confidential inquiries into maternal deaths were introduced in Ghana and Indonesia.

Methods

Clinical review panels were set up as part of the usual process of confidential inquiries, and modifications to the confidential inquiries were introduced. In Ghana, the traditional confidential inquiry process focusing on health facility care was modified to introduce the assessment of positive factors. In addition to the assessment of positive factors, adaptations in Indonesia consisted of including cases of obstetric complications, as well as deaths, and the use of interview testimonials as data sources. Information about resource and time needs for conducting confidential inquiries was collected.

Results

The introduction of positive aspects to the process provided a balanced and more motivating setting for the inquiry. The data obtained from case notes in district hospitals and interview testimonials provided sufficient information to assess why maternal deaths and severe complications occurred. The costs of conducting the inquiries ranged from US $4000 to US $11 000 (per study), and the estimated time required for a panel member to review each case was more than 3 hours.

Conclusion

This study introduced practical ways to encourage the implementation of maternal death reviews, inquiries, and audits that are context specific and, therefore, acceptable to local practitioners.
Maternal death review in Africa
Authors: Pearson Luwei , deBernis Luc , Shoo Rumishael
Published: May 2009

Objective

WHO, UNICEF, and UNFPA with other development partners have supported African Ministries of Health to institutionalize maternal death review (MDR) since 2003. To evaluate the program, its status, lessons learned, and the challenges to success were reviewed in 2007.

Methods

A standard self‐administered questionnaire was sent to Ministries of Health in 46 Sub‐Saharan African countries in May 2007. Completed questionnaires were returned by e‐mail, processed, and analyzed.

Results

Thirty countries completed the survey questionnaire. Maternal death is a notifiable condition in 21 (67%) counties. A national committee has been set up to plan, coordinate, and implement MDR activities in 7 countries. Fifteen countries stated that facility‐based MDR is the main method selected for conducting reviews of the causes of maternal death. Fourteen (47%) countries reported that national MDR guidelines had been developed and 12 (40%) had implemented the guidelines. Fifteen (50%) countries reported that maternal deaths were reviewed and analyzed. Only 7 countries reported that the government had allocated a budget for MDR. Implementation of MDR has led to local policy changes and improvement in quality of maternal health services in several countries. Ten of the 15 countries in which analysis has been conducted reported that recommendations have been implemented at least at the health facility level.

Conclusion

Although use of MDR is increasing in African countries, effective coverage is still low. The institutionalization of MDR requires political commitment, legal and administrative back‐up, financial support, capacity development, simplified reporting forms and procedures, coordinated support of development partners, involvement of professional bodies, and regular supportive follow‐up.