bluuebunny/crossref_metadata_2025 huggingface dataset:
Drinking water from alternative water sources: differences in beliefs, social norms and factors of perceived behavioural control across eight Australian locations
Authors: Dolnicar S. , Hurlimann A.
Published: September 2009

Australia is facing serious challenges in the management of water in various urban and regional locations. Two popular responses to these challenges are increasing supply through alternative water sources such as recycled and desalinated water. However, significant gaps exist in our knowledge of community attitudes to these alternative sources of water, particularly for potable use. This paper reports results from an Australian study of community attitudes to alternative water sources. Sixty six qualitative interviews were held at eight locations with distinctly different water situations. This paper explores all three antecedents to the behaviour of drinking recycled water and desalinated water as postulated by the Theory of Planned Behaviour: attitudes, social norms and factors of perceived behavioural control. Key results indicate that while people hold both positive and negative beliefs (mostly cost, health and environmental concerns) about water from alternative sources, nearly all of them are willing to drink it if the water crisis were to deteriorate further. People also feel they lack knowledge and state that information from scientists would influence their decision to drink recycled and desalinated water most. Friends and relatives are most influential in preventing people from drinking recycled water. The findings reported in this paper have major implications for water policy, and will be of particular interest to water engineers. The paper raises a provocative question: Is it better to avoid public consultation in introducing water from alternative sources?
Bioaugmentation to degrade the organic de-icers acetate and monopropylene glycol at low temperatures
Authors: Forrez I. , Verstraete W.
Published: September 2009

Two de-icers, potassium acetate and monopropylene glycol (MPG), used widespread as a runway and wing de-icer respectively, can exert high BOD in the surrounding waters. A bioaugmentation approach to degrade these de-icer compounds in the drainage water prior to discharge has been tested. A microbial consortium originating from soil was enriched at low temperatures (4°C) in order to adapt to wintertime conditions. With 0.05 g CDW/L of biocatalyst, maximum specific removal rates up to 1.46 and 3.33 g acetate/g CDW d at 4°C were achieved with and without biostimulation respectively. An acetate:MPG mixture of 1:3 at a total COD concentration of 0.80 and 1.20 g/L was degraded in 12 days by 83 and 70% respectively. Bioaugmentation in the field over a period of 25 days showed a removal of 88% MPG compared to 46% in the control. These results demonstrate that bioaugmentation of airport runoff water can be successfully applied to prevent organic de-icer compounds from entering the receiving surface waters.
Ultrasound pre-treatment for anaerobic digestion improvement
Authors: Pérez-Elvira S. , Fdz-Polanco M. , Plaza F. I. , Garralón G. , Fdz-Polanco F.
Published: September 2009

Prior research indicates that ultrasounds can be used in batch reactors as pre-treatment before anaerobic digestion, but the specific energy required at laboratory-scale is too high. This work evaluates both the continuous ultrasound device performance (efficiency and solubilisation) and the operation of anaerobic digesters continuously fed with sonicated sludge, and presents energy balance considerations. The results of sludge solubilisation after the sonication treatment indicate that, applying identical specific energy, it is better to increase the power than the residence time. Working with secondary sludge, batch biodegradability tests show that by applying 30 kWh/m3 of sludge, it is possible to increase biogas production by 42%. Data from continuous pilot-scale anaerobic reactors (V=100 L) indicate that operating with a conventional HRT = 20 d, a reactor fed with pre-treated sludge increases the volatile solids removal and the biogas production by 25 and 37% respectively. Operating with HRT = 15 d, the removal efficiency is similar to the obtained with a reactor fed with non-hydrolysed sludge at HTR = 20 d, although the specific biogas productivity per volume of reactor is higher for the pretreated sludge. Regarding the energy balance, although for laboratory-scale devices it is negative, full-scale suppliers state a net generation of 3–10 kW per kW of energy used.
Influence of sample preservation on endotoxin measurement in water
Authors: O'Toole J. , Sinclair M. , Jeavons T. , Leder K.
Published: September 2009

Appropriate preservation of a range of water types prior to analysis for endotoxin was investigated, including sample storage and addition of sodium thiosulphate. Biologically active endotoxin in water samples was assayed using a chromogenic Limulus Amoebocyte Lysate (LAL) assay. Statistical analysis of measured mean endotoxin levels obtained for samples with and without sodium thiosulphate showed no significant difference in results. There was a 44% mean decline in the concentration of detectable endotoxin in water samples stored at −80°C for 4 weeks compared with samples stored at 4°C and analysed within 24 hours. Freezing of water samples at −80°C in pyrogen-free containers for 4 weeks or longer, then thawing may lead to considerable endotoxin loss; however the addition of sodium thiosulphate to water samples interferes minimally with the LAL assay. These results provide methodological information that can be used to assist researchers in future water endotoxin monitoring studies. The validation and standardisation of water sample preservation protocols are necessary, given the likely increase in the quantification of endotoxin levels in a variety of water sources and the use of such results for health effect determinations.
Use of surrogate modelling for multiobjective optimisation of urban wastewater systems
Authors: Fu G. , Khu S.-T. , Butler D.
Published: September 2009

Simulation models are now available to represent the sewer network, wastewater treatment plant and receiving water as an integrated system. These models can be combined with optimisation methods to improve overall system performance through optimal control. Evolutionary algorithms (EAs) have been proven to be a powerful method in developing optimal control strategies; however, the intensive computational requirement of these methods imposes a limit on their application. This paper explores the potential of surrogate modelling in multiobjective optimisation of urban wastewater systems with a limited number of model simulations. A surrogate based method, ParEGO, is combined with an integrated urban wastewater model to solve real time control problems. This method is compared with the popular NSGA II, by using performance indicators: the hypervolume indicator, additive binary ɛ-indicator and attainment surface. Comparative results show that ParEGO is an efficient and effective method in deriving optimal control strategies for multiple objective control problems with a small number of simulations. It is suggested that ParEGO can greatly improve computational efficiency in the multiobjective optimisation process, particularly for complex urban wastewater systems.
Comparison of the Effects of Conventional and Alternative External Carbon Sources on Enhancing the Denitrification Process
Authors: Swinarski Marek , Makinia Jacek , Czerwionka Krzysztof , Chrzanowska Marta , Drewnowski Jakub
Published: September 2009

Food industry effluents are considered a potential alternative for methanol when seeking external carbon sources to enhance denitrification in municipal wastewater treatment plants (WWTPs). The aim of this study was to determine the immediate effects of dosing different carbon sources on the denitrification capability of process biomass from the Wschod WWTP in Gdansk (northern Poland). Five carbon sources, including settled wastewater, methanol, and three industrial effluents (distillery, brewery, and fish‐pickling process) were tested in two kinds of batch experiments. The acclimation period of biomass to methanol also was investigated in bench‐scale systems. During the conventional batch experiments, with the industrial effluents, the observed nitrate utilization rates (NURs) ranged from 2.4 to 6.0 g N/(kg VSS·h), which were only slightly lower than the rates associated with the use of the readily biodegradable fraction in the municipal (settled) wastewater [4.6 to 7.8 g N/(kg VSS·h)]. The conventional NURs observed with methanol and non‐acclimated process biomass were low [i.e., 0.4 to 1.5 g N/(kg VSS·h)], and a minimum 2‐week acclimation period of biomass to methanol in the bench‐scale systems was needed to reach the level of 4.0 g N/(kg VSS⋅h). In other experiments, dosing the distillery and fish‐pickling effluents at the beginning of the anoxic phase (preceded by the anaerobic phase) resulted in considerably higher (over 20%) NURs compared with the same experiments with the other carbon sources.
Assessing and Improving Technology Integration Skills for Preservice Teachers Using the Teacher Work Sample
Authors: Graham Charles R. , Tripp Tonya , Wentworth Nancy
Published: September 2009

This study explores the efforts at Brigham Young University to improve preservice candidates' technology integration using the Teacher Work Sample (TWS) as an assessment tool. Baseline data that was analyzed from 95 TWSs indicated that students were predominantly using technology for productivity and information presentation purposes even though they had been taught to use technology for active student learning. Researchers discovered that decisions made about technology integration were heavily influenced by field instructors and TWS rubrics. An intervention plan was developed to train field instructors and 99 TWSs were analyzed the following year. The TWSs showed noticeable improvements including increases in the percentage of candidates who involved their K-12 students in using technology in their lessons.
Death at Work in America: Pandemic, Mostly Unacknowledged
Authors: Wypijewski JoAnn
Published: September 2009

Forty years ago, when lots of Americans made things, more of them died in a year on the job than died in a year fighting in Vietnam. This never registered much in the national consciousness. Death in war seems so preventable; death on the job is “an accident.” Now, the numbers have diminished, but the basic pattern holds. Fewer Americans die on the battlefield or on the job. But the death of U.S. soldiers in Iraq or Afghanistan still stirs anger, and the body count is still far lower than death on the job. The 4,924 American soldiers (as of mid-April 2009) who have died in Iraq and Afghanistan since 2001 are known and memorialized; not so the 40,019 workers who died on the job between 2001 and 2007 (not counting the 9/11 dead).
Intracranial vasospasm with subsequent stroke after traumatic subarachnoid hemorrhage in a 22-month-old child
Authors: Nahed Brian V. , Ferreira Manuel , Naunheim Matthew R. , Kahle Kristopher T. , Proctor Mark R. , Smith Edward R.
Published: September 2009

Clinical and radiographic evidence of subarachnoid hemorrhage (SAH)-related vasospasm is rare in children and has not been reported in infants. In this report the authors present the case of a 22-month-old child who developed clinically symptomatic, radiographically identifiable vasospasm after traumatic SAH. To the authors' knowledge, this is the first report of vasospasm associated with SAH in a child this young. This 22-month-old boy fell and had a dense SAH. He had a history of surgically corrected craniosynostosis and nonsymptomatic ventriculomegaly. The boy was evaluated for occult vascular lesions using imaging; none were found and normal vessel caliber was noted. Ten days later, the child developed left-sided weakness and a right middle cerebral artery infarct was identified. Evaluation disclosed significant intracranial vasospasm. This diagnosis was supported by findings on CT angiography, transcranial Doppler ultrasonography, MR imaging, and conventional angiography. The child was treated using intraarterial verapamil with a good result, as well as with conventional intensive care measures to reduce vasospasm. This report documents the first known case of intracranial vasospasm with stroke after SAH in a patient under the age of 2 years. This finding is important because it demonstrates that the entity of SAH-associated vasospasm can affect the very young, widening the spectrum of ages susceptible to this condition. This case is also important because it demonstrates that even very young children can respond to conventional therapeutic interventions such as intraarterial verapamil. Thus, clinicians need to be alert to the possibility of vasospasm as a potential diagnosis when evaluating young children with SAH.
Vertex scalp mass as presenting sign of a complex intracranial vascular malformation
Authors: Massimi Luca , De Bonis Pasquale , Esposito Giuseppe , Novegno Federica , Pettorini Benedetta , Tamburrini Gianpiero , Caldarelli Massimo , Di Rocco Concezio
Published: September 2009

Scalp masses are not infrequently encountered in daily clinical practice. They are represented by a wide spectrum of different clinical entities and are usually managed by an excision or by simple observation. Although it happens rarely, head lumps may hide an underlying cranioencephalic malformation that has to be preoperatively diagnosed to perform an appropriate treatment.

Cerebral arteriovenous malformations (AVMs) are not included among the intracranial malformations connected with a scalp mass. The authors report on the unusual case of a child harboring a complex intracranial AVM that initially presented as a small scalp mass. Actually, this young boy came to the authors' attention just for a small, soft, pulsatile, and reducible mass of the vertex that produced a circumscribed bone erosion. The presence of macrocranium and venous engorgement of the face, however, suggested the presence of an intracranial “mass.” The neuroimaging investigations pointed out a temporal AVM causing dilation of the intracranial sinuses and ectasia of the vein of the scalp; one of the veins was appreciable as a lump on the vertex.
Navigating the gray zone: a guideline for surgical decision making in obstetrical brachial plexus injuries
Authors: Bain James R. , DeMatteo Carol , Gjertsen Deborah , Hollenberg Robert D.
Published: September 2009

Object

In the literature, the best recommendations are imprecise as to the timing and selection of infants with obstetrical brachial plexus injury (OBPI) for surgical intervention. There is a gray zone (GZ) in which the decision as to the benefits and risks of surgery versus no surgery is not clear. The authors propose to describe this category, and they have developed a guideline to assist surgical decision-making within this GZ.

Methods

The authors first performed a critical review of the medical literature to determine the existence of a GZ in other clinical publications. In those reports, 47–89% of infants with OBPI fell within such a GZ. Complete recovery in those reported patients ranged from 9 to 59%. Using a prospective inception cohort design, all infants referred to the OBPI Clinic at McMaster Children's Hospital were systematically evaluated up to 3 years of age. The Active Movement Scale scores were compared for surgical and nonsurgical groups of infants in the GZ to identify any important trends that would guide surgical decision-making.

Results

In the authors' population of infants with OBPI, 81% fell within the GZ, of whom 44% achieved complete recovery. Mean scores differed significantly between surgery and no surgery groups in terms of total Active Movement Scale score and shoulder abduction and flexion at 6 months. Elbow flexion and external rotation differed at 3 months.

Conclusions

There is compelling evidence that there is a group of infants with OBPI in whom the assessment of the risk/benefit ratio for surgical versus nonsurgical treatment is not evident. These infants reside within what the authors have called the GZ. Based on their results, a guideline was derived to assist clinicians working with infants with OBPI to navigate the GZ.
Internal structure in pineal cysts on high-resolution magnetic resonance imaging: not a sign of malignancy
Authors: Pastel David A. , Mamourian Alexander C. , Duhaime Ann-Christine
Published: September 2009

Object

In this paper, the authors' goal was to determine whether benign pineal cysts have smooth walls or internal structure on high-resolution MR imaging and to evaluate their imaging characteristics on FLAIR images.

Methods

The authors retrospectively reviewed the MR imaging findings in 60 consecutive patients who were reported to have pineal cysts over a 19-month period. Patients were identified retrospectively using a word search of radiology reports. Of these 60 patients, 24 with stable follow-up imaging or pathological proof of a pineal cyst were included in this study. In all cases, axial or sagittal FLAIR images were available, and in 10 of 24 patients the authors obtained sagittal images using fast imaging employing steady-state acquisition (FIESTA). For those cases in which FIESTA studies were obtained, the authors classified the cysts into 1 of 4 categories based on their appearance. Eighteen of 24 cases were performed with intravenous contrast.

Results

Of the 24 cases, 21 had signal intensity on FLAIR images that differed from that of CSF. Of the 10 cases with FIESTA, 6 had evidence of internal structure within the pineal cyst. The authors found it of interest that 20 of the 24 patients were female.

Conclusions

Although the presence of a thin wall supports the diagnosis of a benign pineal cyst, fine internal septations or small internal cysts are common on high-resolution MR imaging and this finding should not be considered evidence of an underlying tumor. It is typical for pineal cysts to have relaxation times that differ from CSF as determined by FLAIR imaging.
Experimental investigation of encephalomyosynangiosis using gyrencephalic brain of the miniature pig: histopathological evaluation of dynamic reconstruction of vessels for functional anastomosis
Authors: Nakamura Mitsunobu , Imai Hideaki , Konno Kenjiro , Kubota Chisato , Seki Koji , Puentes Sandra , Faried Ahmad , Yokoo Hideaki , Hata Hidekazu , Yoshimoto Yuhei , Saito Nobuhito
Published: September 2009

Object

Encephalomyosynangiosis (EMS) is a surgical treatment for moyamoya disease that is widely used to provide increased intracranial blood flow via revascularization by arterial anastomosis from the external carotid artery. However, the angiogenic mechanism responsible for the revascularization induced by EMS has not been systematically evaluated. In this study the authors investigated the chronological angiogenic changes associated with EMS to clarify the favorable factors and identify revascularization mechanisms by using an experimental internal carotid artery occlusion (ICAO) model in the miniature pig.

Methods

Fourteen miniature pigs were used, 11 of which underwent ICAO before transcranial surgery for EMS was performed. Animals were allowed to recover for 1 week (4 pigs) or 4 weeks (7 pigs) after EMS. Control group animals were treated in the same way, but without occlusion (3 pigs). Magnetic resonance imaging, angiography, and histological investigation were performed.

Results

One week after EMS, on histological examination of both the ICAO and control groups it was found that the transplanted temporal muscle had adhered to the arachnoid via a granulation zone, which was enriched with immune cells such as macrophages associated with the angiogenic process. Four weeks after EMS, angiography and histological examination of the ICAO group showed patent anastomoses between the external carotid artery and the cortical arteries without any detectable boundary between the temporal muscle and the cerebral cortex. In contrast, histological examination of the control group found scar tissue between the cerebral cortex and temporal muscle.

Conclusions

The initial step for formation of anastomoses resembles the process of wound healing associated with repair processes such as active proliferation of macrophages and angiogenesis within the new connective tissue. Functional revascularization requires a suitable environment (such as tissue containing vascular beds) and stimulus (such as ischemia) to induce vascular expansion.
Resonant and notch behavior in intracranial pressure dynamics
Authors: Wagshul Mark E. , Kelly Erin J. , Yu Hui Jing , Garlick Barbara , Zimmerman Tom , Egnor Michael R.
Published: September 2009

Object

The intracranial pulse pressure is often increased when neuropathology is present, particularly in cases of increased intracranial pressure (ICP) such as occurs in hydrocephalus. This pulse pressure is assumed to originate from arterial blood pressure oscillations entering the cranium; the fact that there is a coupling between the arterial blood pressure and the ICP is undisputed. In this study, the nature of this coupling and how it changes under conditions of increased ICP are investigated.

Methods

In 12 normal dogs, intracarotid and parenchymal pulse pressure were measured and their coupling was characterized using amplitude and phase transfer function analysis. Mean intracranial ICP was manipulated via infusions of isotonic saline into the spinal subarachnoid space, and changes in transfer function were monitored.

Results

Under normal conditions, the ICP wave led the arterial wave, and there was a minimum in the pulse pressure amplitude near the frequency of the heart rate. Under conditions of decreased intracranial compliance, the ICP wave began to lag behind the arterial wave and increased significantly in amplitude. Most interestingly, in many animals the pulse pressure exhibited a minimum in amplitude at a mean pressure that coincided with the transition from a leading to lagging ICP wave.

Conclusions

This transfer function behavior is characteristic of a resonant notch system. This may represent a component of the intracranial Windkessel mechanism, which protects the microvasculature from arterial pulsatility. The impairment of this resonant notch system may play a role in the altered pulse pressure in conditions such as hydrocephalus and traumatic brain swelling. New models of intracranial dynamics are needed for understanding the frequency-sensitive behavior elucidated in these studies and could open a path for development of new therapies that are geared toward addressing the pulsation dysfunction in pathological conditions, such as hydrocephalus and traumatic brain injury, affecting ICP and flow dynamics.
Keyhole to the brain: Walter Dandy and neuroendoscopy
Authors: Hsu Wesley , Li Khan W. , Bookland Markus , Jallo George I.
Published: September 2009

In the early 1920s, Walter E. Dandy began translating the field of endoscopy to neurosurgery. In the ensuing years, Dandy, who would become known as the “Father of Neuroendoscopy,” applied his own ingenuity in combination with guidance from prominent medical contemporaries in the development of the early neuroendoscope. This paper reviews his contributions to the early evolution of this growing and important field of neurosurgery.
Intracranial growing teratoma syndrome mimicking tumor relapse: a diagnostic dilemma
Authors: Kong Doo-Sik , Nam Do-Hyun , Lee Jung-Il , Park Kwan , Kim Jong Hyun , Shin Hyung Jin
Published: September 2009

Object

It is important to differentiate growing teratoma syndrome (GTS) from tumor recurrence in the setting of an enlarging residual mass present after treatment of intracranial germ cell tumors (GCTs). The aim of this study was to determine the incidence of intracranial GTS and present its clinical manifestations in detail.

Methods

The authors performed a retrospective cohort study of 52 consecutive patients with newly diagnosed intracranial GCTs who presented between January 2000 and December 2006. The records were screened to identify a study cohort in which all patients had regrowing tumor mass despite normalization of tumor markers during or after treatment of GCTs.

Results

In 6 (11.5%) of 52 patients the pathological diagnosis was GTS. The median patient age at diagnosis was 14.5 years (range 2 months–17 years), and the primary tumors included 4 mixed GCTs and 2 immature teratomas. After second-look surgery, histological testing revealed the lesions to be mature teratoma in all patients. Three of 6 patients subsequently underwent radiation therapy and 1 patient received additional chemotherapy for spinal seeding.

Conclusions

In enlarging residual masses after treatment of intracranial GCTs, GTS should be kept in mind in the differential diagnosis of tumor recurrence especially if there is a radiographic mismatch with serum marker test results. If technically feasible, second-look surgery may be necessary for an accurate diagnosis.
The outcome of tethered cord release in secondary and multiple repeat tethered cord syndrome
Authors: Al-Holou Wajd N. , Muraszko Karin M. , Garton Hugh J. , Buchman Steven R. , Maher Cormac O.
Published: September 2009

Object

After primary repair of a myelomeningocele or a lipomyelomeningocele, patients can present with symptoms of secondary tethered cord syndrome (TCS). After surgical untethering, a small percentage of these patients can present with multiple repeat TCS. In patients presenting with secondary or multiple repeat TCS, the role as well the expected outcomes of surgical untethering are not well defined.

Methods

Eighty-four patients who underwent spinal cord untethering after at least 1 primary repair were retrospectively evaluated using scaled and subjective outcome measures at short-term and long-term follow-up visits. Outcomes were analyzed for predictive measures using multivariate logistic regression.

Results

Surgical untethering was performed in 66 patients with myelomeningoceles and 18 patients with lipomyelomeningoceles. Fourteen patients underwent multiple repeat spinal cord untethering. Patients were followed up for an average of 6.2 years. Most patients had stability of function postoperatively. Motor function and weakness improved in 7 and 16% of patients at 6 months, respectively, and 6 and 19% of patients at long-term follow-up evaluation, respectively. Of the patients who presented with back pain, 75% had improvement in symptoms at 6 months postoperatively. Younger age at untethering was significantly associated with worse long-term neurological outcomes. The number of previous untethering procedures, original diagnosis, sex, anatomical level, and degree of untethering had no effect on surgical outcomes.

Conclusions

Patients presenting with secondary or multiple repeat TCS may benefit from surgical untethering.
Intracardiac migration of a distal shunt catheter: an unusual complication of ventricular shunts
Authors: Rizk Elias , Dias Mark S. , Verbrugge Joel , Boop Frederick A.
Published: September 2009

Unusual complications of peritoneal shunts are a well-known occurrence. The authors present 2 cases of intracardiac migration of a distal shunt catheter, summarizing the diagnosis and management of each case. This complication seems to be a rare occurrence; the transgression of the jugular vein leading to intracardiac migration of a shunt catheter has been reported only 6 times previously. The authors highlight the importance of careful and proper placement of the distal peritoneal catheter during the tunneling process, in particular avoiding too deep a penetration of the shunt passer into the neck tissues and too medial a shunt passage near the sternal notch to avoid vascular structures.
Postoperative cerebrospinal fluid wound leakage as a predictor of shunt infection: a prospective analysis of 205 cases
Authors: Jeelani N. u. Owase , Kulkarni Abhaya V. , DeSilva Pani , Thompson Dominic N. P. , Hayward Richard D.
Published: September 2009

Object

The purpose of this study was to audit some of the risk factors for CSF shunt infections within the authors' practice and analyze the statistical significance of these factors.

Methods

The authors used their own contemporaneously collected shunt database in this study. All shunt procedures performed over a 2-year period between March 2000 and February 2002 at Great Ormond Street Hospital, London, were analyzed. For the purposes of this study, positive CSF cultures were a prerequisite for a data set to qualify as a shunt infection. The authors studied the effects of patient age, the etiology of hydrocephalus, whether the surgery was primary shunt placement versus a revision, the surgeon's level of experience, whether the surgery was performed on an elective or emergency basis, and the presence or absence of a perioperative CSF leak. Statistical analyses were performed.

Results

Two hundred and five patients with a mean (± SD) age at surgery of 27.9 ± 43.0 months were included in this study. Shunt infections developed in 17 patients (8.3%) at a median of 42 days postoperatively (range 14–224 days). The presence of a perioperative CSF leak was the only variable that showed a statistically significant association with the occurrence of a shunt infection, with an infection rate of 57.1% compared to 4.7% in cases with no leak (OR 27.0 [95% CI 7.7–94.3]). The cause of hydrocephalus, elective versus emergency surgery, level of surgeon experience, a primary versus a revision procedure, and patient age did not have a bearing on the infection risk.

Conclusions

The presence of a perioperative CSF leak puts pediatric patients at a very high risk of shunt infection. Aside from prevention, the optimal management of such CSF leaks require further investigation.
Experiences with a gravity-assisted valve in hydrocephalic children
Authors: Haberl Ernst Johannes , Messing-Juenger Martina , Schuhmann Martin , Eymann Regina , Cedzich Cornelia , Fritsch Michael J. , Kiefer Michael , Van Lindert Eric Johannes , Geyer Christian , Lehner Markus , Rohde Veit , Stroux Andrea , von Berenberg Petra
Published: September 2009

Object

Over the past decade, a gravity-assisted valve (GAV) has become a standard device in many European pediatric hydrocephalus centers. Because past comparative clinical outcome studies on valve design have not included any GAV, the authors in this trial evaluated the early results of GAV applications in a pediatric population.

Methods

For a minimum of 2 years the authors monitored 169 of 182 hydrocephalic children who received a pediatric GAV at their first CSF shunt insertion (61.5%) or as a substitute for any differential pressure valve (38.5%) at 1 of 7 European pediatric hydrocephalus centers. Outcomes were categorized as valve survival (primary outcome) or shunt survival (secondary outcome). The end point was defined as valve explantation.

Results

Within a follow-up period of 2 years, the valve remained functional in 130 (76.9%) of 169 patients. One hundred eight of these patients (63.9%) had an uncomplicated clinical course without any subsequent surgery, and 22 (13%) were submitted to a valve-preserving catheter revision without any further complications during the follow-up period. Thirty-nine patients (23.1%) reached an end point of valve explantation: 13 valve failures from infection (7.7%), 8 (4.7%) from overdrainage, and 18 (10.6%) from underdrainage.

Conclusions

Compared with nongravitational shunt designs, a GAV does not substantially affect the early complication rate. Valve-preserving shunt revisions do not increase the risk of subsequent valve failure and therefore should not be defined as an end point in studies on valve design. A significant impact of any well-established valve design on the early complication rate in shunt surgery is not supported by any current data; therefore, this correlation should be dismissed. As overdrainage-related complications have been shown to occur late, the presumed advantages of a pediatric GAV remain to be shown in a long-term study.
Role of Rac1-regulated signaling in medulloblastoma invasion
Authors: Zavarella Salvatore , Nakada Mitsutoshi , Belverud Shawn , Coniglio Salvatore J. , Chan Amanda , Mittler Mark A. , Schneider Steven J. , Symons Marc
Published: September 2009

Object

Medulloblastomas are the most common malignant brain tumors in children. These tumors are highly invasive, and patients harboring these lesions are frequently diagnosed with distant spread. In this study, the authors investigated the role of Rac1, a member of the Rho family of small guanosine triphosphatases, in medulloblastoma invasion.

Methods

Three established medulloblastoma cell lines were used: DAOY, UW-228, and ONS-76. Specific depletion of Rac1 protein was accomplished by transient transfection of small interfering RNA. Cell invasion through extracellular matrix (Matrigel) was quantified using a transwell migration assay. Mitogen activated protein kinase activation was determined using phospho-MAP kinase–specific antibodies, and inhibition of MAP kinase pathways was achieved by specific small molecule inhibitors. Localization of Rac1 and its expression levels were determined by immunohistochemical analysis using a Rac1-specific antibody, and Rac1 activation was qualitatively assessed by Rac1 plasma membrane association.

Results

Small interfering RNA–mediated depletion of Rac1 strongly inhibited medulloblastoma cell invasion. Although depletion of Rac1 inhibited the proliferation of UW-228 cells, and of ONS-76 cells to a lesser extent, it stimulated the proliferation of DAOY cells. Depletion of Rac1 also inhibited the activation of the ERK and JNK MAP kinase pathways, and inhibition of either pathway diminished invasion and proliferation. Immunohistochemical analysis demonstrated that the Rac1 protein was overexpressed in all medulloblastoma tumors examined, and indicated that Rac1 was hyperactive in 6 of 25 tumors.

Conclusions

The authors' data show that Rac1 is necessary for the invasive behavior of medulloblastoma cells in vitro, and plays a variable role in medulloblastoma cell proliferation. In addition, these results indicate that Rac1 stimulates medulloblastoma invasion by activating the ERK and JNK pathways. The authors suggest that Rac1 and signaling elements controlled by this guanosine triphosphatase may serve as novel targets for therapeutic intervention in malignant medulloblastomas.
Pediatric tethered cord syndrome: response of scoliosis to untethering procedures
Authors: McGirt Matthew J. , Mehta Vivek , Garces-Ambrossi Giannina , Gottfried Oren , Solakoglu Can , Gokaslan Ziya L. , Samdani Amer , Jallo George I.
Published: September 2009

Object

Tethered cord syndrome (TCS) is frequently associated with scoliosis in the pediatric population. Following spinal cord untethering, many patients continue to experience progression of spinal deformity. However, the incidence rate, time course, and risk factors for scoliosis progression following tethered cord release remain unclear. The aim of this study was to determine factors associated with scoliosis progression and whether tethered cord release alone would halt curve progression in pediatric TCS.

Methods

The authors retrospectively reviewed 27 consecutive pediatric cases of spinal cord untethering associated with scoliosis. The incidence rate and factors associated with scoliosis progression (> 10° increased Cobb angle) after untethering were evaluated using the Kaplan-Meier method.

Results

The mean age of the patients was 8.9 years. All patients underwent cord untethering for lower-extremity weakness, back and leg pain, or bowel and bladder changes. Mean ± SD of the Cobb angle at presentation was 41 ± 16°. The cause of the spinal cord tethering included previous myelomeningocele repair in 14 patients (52%), fatty filum in 5 (18.5%), lipomeningocele in 3 (11%), diastematomyelia in 2 (7.4%), arthrogryposis in 1 (3.7%), imperforate anus with an S-2 hemivertebra in 1 (3.7%), and lipomyelomeningocele with occult dysraphism in 1 (3.7%). Mean follow-up was 6 ± 2 years. Twelve patients (44%) experienced scoliosis progression occurring a median of 2.4 years postoperatively and 8 (30%) required subsequent fusion for progression. At the time of untethering, scoliosis < 40° was associated with a 32% incidence of progression, whereas scoliosis > 40° was associated with a 75% incidence of progression (p < 0.01). Patients with Risser Grades 0–2 were also more likely to experience scoliosis progression compared with Risser Grades 3–5 (p < 0.05). Whereas nearly all patients with Risser Grades 0–2 with curves > 40° showed scoliosis progression (83%), 54% of patients with Risser Grades 0–2 with curves < 40° progressed, and no patients with Risser Grades 3–5 with curves < 40° progressed following spinal cord untethering.

Conclusions

In this experience with pediatric TCS-associated scoliosis, patients with Risser Grades 3–5 and Cobb angles < 40° did not experience curve progression after tethered cord release. Patients with Risser Grades 0–2 and Cobb angles > 40° were at greatest risk of curve progression after cord untethering. Pediatric patients with TCSassociated scoliosis should be monitored closely for curve progression using standing radiographs after spinal cord untethering, particularly those with curves > 40° or who have Risser Grades 0–2.
Combined endoscopic-microsurgical approach for transsphenoidal (sphenopalatine) encephalocele with an intralesional pituitary gland
Authors: Faggin Roberto , Pentimalli Luigi , Grazzini Maurizia , Saetti Roberto , Drigo Paola , d'Avella Domenico
Published: September 2009

The treatment of the transsphenoidal sphenopalatine encephalocele in infants has not been thoroughly described in the literature. Pterional and subfrontal transbasal approaches have been reported as the advised treatment for transethmoidal encephalocele, but their feasibility for transsphenoidal encephalocele remains controversial, particularly in neonates. The potential harm to vital structures within the herniated tissue and intraoperative bleeding have been considered the major cause of poor postoperative results.

The authors present the case of a full-term newborn with a cleft palate and a large transsphenoidal sphenopalatine encephalocele, which filled the nasopharyngeal space and provided MR imaging evidence of an intralesional pituitary gland.

The lesion is unusual, and the extracranial intraoral endoscopic approach with an optimal outcome and sparing of the pituitary tissue has never been described in detail in an infant of this age.
Shunt malfunction causing acute neurological deterioration in 2 patients with previously asymptomatic Chiari malformation Type I
Authors: Elliott Robert , Kalhorn Stephen , Pacione Donato , Weiner Howard , Wisoff Jeffrey , Harter David
Published: September 2009

Patients with symptomatic Chiari malformation Type I (CM-I) typically exhibit a chronic, slowly progressive disease course with evolution of symptoms. However, some authors have reported acute neurological deterioration in the setting of CM-I and acquired Chiari malformations. Although brainstem dysfunction has been documented in patients with CM-II and hydrocephalus or shunt malfunction, to the authors' knowledge only 1 report describing ventriculoperitoneal (VP) shunt malfunction causing neurological deterioration in a patient with CM-I exists.

The authors report on their experience with the treatment of previously asymptomatic CM-I in 2 children who experienced quite different manifestations of acute neurological deterioration secondary to VP shunt malfunction. Presumably, VP shunt malfunction created a positive rostral pressure gradient across a stenotic foramen magnum, resulting in tetraparesis from foramen magnum syndrome in 1 patient and acute ataxia and cranial nerve deficits from syringobulbia in the other. Although urgent shunt revisions yielded partial recovery of neurological function in both patients, marked improvement occurred only after posterior fossa decompression.
Topographic influences on recent changes of very small glaciers in the Monashee Mountains, British Columbia, Canada
Authors: DeBeer Christopher M. , Sharp Martin J.
Published: September 2009

An analysis of the local topographic setting of very small (<0.4 km2) glaciers within a small region of the Monashee Mountains, British Columbia, was conducted to investigate its influence on recent changes in the extent of these glaciers. Net changes in glacier extent were determined from a detailed manual comparison of remotely sensed imagery acquired in 1951, 2001 and 2004. Most of the 86 glaciers included in the study showed no observable net change in area over the study period, while six glaciers retreated, four disappeared entirely and only one advanced. Indices derived to characterize elements of the local topographic setting that might affect the local mass balance suggest that most of the glaciers are situated in locations that favor ice preservation by enhancing mass input and/or reducing ablation rates. Glaciers situated in less favorable settings generally either decreased in area or disappeared. The results suggest that most of the glaciers studied have retreated as far as they are likely to under the climatic conditions of the late 20th century.
Temporal dynamics of a jökulhlaup system
Authors: Ng Felix , Liu Shiyin
Published: September 2009

Recurring jökulhlaups from ice-dammed lakes often form irregular time sequences that are seemingly unpredictable. Using the flood dates of Merzbacher Lake, Kyrgyzstan, as an example, we study these sequences through a model of lake filling and drainage where flood events initiate at a threshold water depth. Even with a constant threshold, model simulation can explain key aspects of the Merzbacher flood sequence. General analysis of model dynamics reveals a pacing mechanism that links one flood to the next, and which may be represented mathematically as an iterative map. This theory clarifies how environmental factors govern the long-term pattern of flood timings and their frequency distribution in the year. A reconstruction of the past level of Merzbacher Lake also suggests that its flood-initiation threshold decreases with the rate of lake-level rise. These results may help us understand how to forecast future outbursts from jökulhlaup lakes.
Properties of a marine ice layer under the Amery Ice Shelf, East Antarctica
Authors: Craven Mike , Allison Ian , Fricker Helen Amanda , Warner Roland
Published: September 2009

The Amery Ice Shelf, East Antarctica, undergoes high basal melt rates near the southern limit of its grounding line where 80% of the ice melts within 240 km of becoming afloat. A considerable portion of this later refreezes downstream as marine ice. This produces a marine ice layer up to 200 m thick in the northwest sector of the ice shelf concentrated in a pair of longitudinal bands that extend some 200 km all the way to the calving front. We drilled through the eastern marine ice band at two locations 70 km apart on the same flowline. We determine an average accretion rate of marine ice of 1.1 ± 0.2 m a−1, at a reference density of 920 kg m−3 between borehole sites, and infer a similar average rate of 1.3 ± 0.2 m a−1 upstream. The deeper marine ice was permeable enough that a hydraulic connection was made whilst the drill was still 70–100 m above the ice-shelf base. Below this marine close-off depth, borehole video imagery showed permeable ice with water-filled cavities and individual ice platelets fused together, while the upper marine ice was impermeable with small brine-cell inclusions. We infer that the uppermost portion of the permeable ice becomes impermeable with the passage of time and as more marine ice is accreted on the base of the shelf. We estimate an average closure rate of 0.3 m a−1 between the borehole sites; upstream the average closure rate is faster at 0.9 m a−1. We estimate an average porosity of the total marine ice layer of 14–20%, such that the deeper ice must have even higher values. High permeability implies that sea water can move relatively freely through the material, and we propose that where such marine ice exists this renders deep parts of the ice shelf particularly vulnerable to changes in ocean properties.
Retreating alpine glaciers: increased melt rates due to accumulation of dust (Vadret da Morteratsch, Switzerland)
Authors: Oerlemans J. , Giesen R.H. , Van Den Broeke M.R.
Published: September 2009

The automatic weather station (AWS) on the snout of the Vadret da Morteratsch, Switzerland, has delivered a unique 12 year meteorological dataset from the ablation zone of a temperate glacier. This dataset can be used to study multi-annual trends in the character of the surface energy budget. Since 2003 there has been a substantial darkening of the glacier tongue due to the accumulation of mineral and biogenic dust. The typical surface albedo in summer has dropped from 0.32 to 0.15. We have analysed the implications of the lowered albedo for the energy balance and the annual ablation. For the 4 year period 2003–06, the decreased albedo caused an additional removal of about 3.5 m of ice. Calculations with an energy-balance model show that the same increase in ablation is obtained by keeping the ice albedo fixed to 0.32 and increasing the air temperature by 1.7 K. Our analysis confirms that for retreating glaciers the deposition of dust from exposed side moraines on the glacier surface constitutes an important feedback mechanism. The mineral dust stimulates the growth of algae, lowers the surface albedo, enhances the melt rates, and thereby facilitates the further retreat of the glacier snout.
Indices for estimating fractional snow cover in the western Tibetan Plateau
Authors: Shreve Cheney M. , Okin Gregory S. , Painter Thomas H.
Published: September 2009

Snow cover in the Tibetan Plateau is highly variable in space and time and plays a key role in ecological processes of this cold-desert ecosystem. Resolution of passive microwave data is too low for regional-scale estimates of snow cover on the Tibetan Plateau, requiring an alternate data source. Optically derived snow indices allow for more accurate quantification of snow cover using higher-resolution datasets subject to the constraint of cloud cover. This paper introduces a new optical snow index and assesses four optically derived MODIS snow indices using Landsat-based validation scenes: MODIS Snow-Covered Area and Grain Size (MODSCAG), Relative Multiple Endmember Spectral Mixture Analysis (RMESMA), Relative Spectral Mixture Analysis (RSMA) and the normalized-difference snow index (NDSI). Pearson correlation coefficients were positively correlated with the validation datasets for all four optical snow indices, suggesting each provides a good measure of total snow extent. At the 95% confidence level, linear least-squares regression showed that MODSCAG and RMESMA had accuracy comparable to validation scenes. Fusion of optical snow indices with passive microwave products, which provide snow depth and snow water equivalent, has the potential to contribute to hydrologic and energy-balance modeling in the Tibetan Plateau.
Communication, Comanagement, and Collaborative Care for Children and Youth with Special Healthcare Needs
Authors: Stille Christopher J.
Published: September 2009

CME Educational Objectives

1.

Demonstrate the role of primary care-specialist communication in high-quality care delivery.

2.

Apply the role of communication in the larger concept of primary care provider-specialist comanagement.

3.

Identify a suitable comanagement approach to patient care in individual practices.
On the Threshold to the Adult Medical Home: Care Coordination in Transition
Authors: White Patience H. , Hackett Patti
Published: September 2009

CME Educational Objectives

1.

Outline the role of care coordination for transitioning youth to adult medical homes.

2.

Distinguish the different tasks required of each member of the care team to achieve a smooth transition to an adult care model.

3.

Identify tools useful for assisting in the transition process.