bluuebunny/crossref_metadata_2025_split huggingface dataset:
Moyamoya disease: functional and neurocognitive outcomes in the pediatric and adult populations
Authors: Weinberg David G. , Rahme Rudy J. , Aoun Salah G. , Batjer H. Hunt , Bendok Bernard R. 
Published: June 2011

Object
Moyamoya disease is an occlusive cerebrovascular disorder commonly resulting in neurocognitive impairment. The cognitive outcome parameters commonly affected are intelligence, memory, executive function, and quality of life. In this paper, the authors review the existing literature on cognitive and clinical outcomes in adult and pediatric moyamoya populations separately.

Methods
A systematic review of the cognitive and clinical outcome literature was performed using the PubMed/MEDLINE database. Outcomes data were contrasted between adult and pediatric populations.

Results
Intelligence is the main cognitive outcome parameter affected in pediatric patients with moyamoya disease, whereas adults most commonly suffer from executive function impairment. Memory has not been studied sufficiently in pediatric patients, and its dysfunction in the adult population remains controversial. Quality of life has not been studied appropriately in either population. Surgical revascularization is the only beneficial treatment option, and a combination of direct and indirect bypass techniques has shown benefit, but the impact on the above-mentioned parameters has not been sufficiently elucidated.

Conclusions
Moyamoya disease affects the cognition and daily function in pediatric patients to a greater extent than in adult patients. Due to the rarity of the disease, there is a distinct lack of high-level evidence regarding cognitive and clinical outcomes.
Moyamoya disease: a review of histopathology, biochemistry, and genetics
Authors: Weinberg David G. , Arnaout Omar M. , Rahme Rudy J. , Aoun Salah G. , Batjer H. Hunt , Bendok Bernard R. 
Published: June 2011

Object
Moyamoya disease (MMD) is a rare cerebrovascular disorder involving stenosis of the major vessels of the circle of Willis and proximal portions of its principal branches. Despite concerted investigation, the pathophysiology of the disorder has not been fully elucidated. Currently, the major proteins believed to play an active role in the pathogenesis include vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), transforming growth factor–β1 (TGFβ1), and granulocyte colony-stimulating factor (G-CSF). In terms of the genetics, recent literature suggests a low penetrance autosomal dominant or polygenic mode of transmission involving chromosomes 3, 6, 8, 12, and 17 for familial MMD. This review summarizes the current knowledge on the histopathology, pathophysiology and genetics of MMD.

Methods
A PubMed/Medline systematic study of the literature was performed, from which 45 articles regarding MMD pathophysiology were identified and analyzed.

Conclusions
Moyamoya disease is characterized by the intimal thickening and media attenuation of the proximal vessels of the circle of Willis as well as the development of an aberrant distal vascular network. The primary proteins that are currently implicated in the pathophysiology of MMD include VEGF, bFGF, HGF, TGFβ1, and G-CSF. Furthermore, the current literature on familial MMD has pointed to a low penetrance autosomal dominant or polygenic mode of transmittance at loci on chromosomes 3, 6, 8, 12, and 17.
Bilateral subthalamic nucleus deep brain stimulation for dopa-responsive dystonia in a 6-year-old child
Authors: Tormenti Matthew J. , Tomycz Nestor D. , Coffman Keith A. , Kondziolka Douglas , Crammond Donald J. , Tyler-Kabara Elizabeth C. 
Published: June 2011

Tyrosine hydroxylase (TH) deficiency is a rare autosomal recessive metabolic disease that results in the decreased production of catecholamines. Standard treatment relies on combinations of levodopa and carbidopa, anticholinergic agents, serotonergic agonists, and monamine oxidase B inhibitors. Unfortunately, severely affected children often require escalating doses of medication and suffer from dyskinesias as well as significant on/off symptomatology.
The authors present a case of medically intractable dopa-responsive dystonia in a 6-year-old boy whose condition significantly improved with bilateral subthalamic nucleus deep brain stimulation. This case is unique in its novel approach to tyrosine hydroxylase deficiency and the young age of the patient.
Minimally invasive lumbar microdiscectomy in pediatric patients: a series of 6 patients
Authors: Thomas Jonathan G. , Hwang Steven W. , Whitehead William E. , Curry Daniel J. , Luerssen Thomas G. , Jea Andrew 
Published: June 2011

Object
Lumbar disc herniation is rare in the pediatric age group, but may still cause a significant amount of pain and disability. Whereas minimally invasive surgery (MIS) for lumbar disc herniation is routinely performed in adults, it has not yet been described in the pediatric population. The purpose of this study was to describe the surgical results of pediatric MIS-treated lumbar disc disease.

Methods
The authors retrospectively reviewed a series of 6 consecutive cases of lumbar microdiscectomy performed using MIS techniques between April 2008 and July 2010. Presenting symptoms, physical examination findings, and preoperative MR imaging results were obtained from medical records. Perioperative results, including blood loss, length of hospital stay, and complications were assessed. Findings at latest follow-up evaluation were also recorded.

Results
This report represents the first surgical series regarding pediatric lumbar microdiscectomies performed using MIS. The mean patient age was 16 years (range 14–17 years); there were 4 girls and 2 boys. Preoperative signs and symptoms of radiculopathic pain were notable in 100% of patients, and myotomal weakness was noted in 33% of patients. The first line of treatment in all patients was a period of conservative management lasting an average of 11.5 months (range 6–12 months). The mean intraoperative blood loss was 10.8 ml, and the mean postoperative length of stay was 1.3 days. There were no complications in this small series.

Conclusions
The treatment of pediatric lumbar disc herniation by using MIS techniques can be safe and efficacious. However, further study with a larger number of patients and longer follow-up is needed to compare outcomes between MIS and open microdiscectomies.
Perioperative seizure incidence and risk factors in 223 pediatric brain tumor patients without prior seizures
Authors: Hardesty Douglas A. , Sanborn Matthew R. , Parker Whitney E. , Storm Phillip B. 
Published: June 2011

Object
The incidence of, and risk factors for, perioperative seizures and the need for perioperative antiepileptic drugs (AEDs) in previously seizure-free children with brain tumors remains unclear. The authors have undertaken a review of previously seizure-free pediatric patients with brain tumors undergoing resection to identify the incidence of seizures in the perioperative period, and to characterize risk factors for perioperative seizures in this population.

Methods
A retrospective review was conducted of all patients between 0 and 19 years of age without prior seizures who underwent intracranial tumor resection at the authors' institution between January 2005 and December 2009.

Results
Of the 223 patients undergoing 229 operations, 7.4% experienced at least 1 clinical seizure during the surgical admission. Over half of all tumors were supratentorial. Only 4.4% of patients received prophylactic AEDs. Independent factors associated with perioperative seizures included supratentorial tumor, age < 2 years, and hyponatremia due to syndrome of inappropriate antidiuretic hormone or cerebral salt wasting. Tumor type, lobe affected, operative blood loss, and length of surgery were not independently associated with seizure incidence.

Conclusions
Perioperative seizures in previously seizure-free children undergoing resection of brain tumors are associated with supratentorial tumor location, age < 2 years, and postoperative hyponatremia. Perioperative seizures are not associated with tumor pathology, tumor size, or frontotemporal location. Due to the low incidence of seizures in this series in patients more than 2 years old with normal serum sodium, the authors recommend that pediatric patients with brain tumors not routinely receive perioperative prophylactic AEDs. However, the role for prophylaxis in patients younger than 2 years of age deserves further study.
Complications of endoscopic third ventriculostomy
Authors: Bouras Triantafyllos , Sgouros Spyros 
Published: June 2011

Object
Endoscopic third ventriculostomy (ETV) is an established treatment for hydrocephalus. Most studies focus on success rate, and complications are insufficiently documented. The aim of this study was to perform a systematic review of ETV complications.

Methods
A Medline search discovered 34 series of ETV with detailed complications reports (17 series involving exclusively pediatric patient populations, 6 series involving exclusively adults, and 11 series involving mixed adult and pediatric populations).

Results
The analysis included 2985 ETVs performed in 2884 patients. The cause of hydrocephalus was aqueductal stenosis in 29.3% of patients, tumor in 37.6%, meningomyelocele in 7.6%, cysts in 2.6%, cerebellar infarct in 0.9%, Dandy-Walker malformation in 0.6%, and Chiari malformation Type I in 0.4%; 7.4% of the patients had posthemorrhagic hydrocephalus, 1.8% had postinfectious hydrocephalus, and 1.2% had normal pressure hydrocephalus. Hydrocephalus was due to other causes in 1.3% of cases and the cause was not reported in 9.8%. The overall complication rate was 8.5%. The rate of permanent morbidity was 2.38%; the rate of permanent neurological complications was 1.44% (hemiparesis, gaze palsy, memory disorders, altered consciousness), and the rate of permanent hormonal morbidity was 0.94% (diabetes insipidus, weight gain, precocious puberty). The rate of intraoperative hemorrhage rate was 3.7%; the rate of severe intraoperative hemorrhage was 0.6% (including a 0.21% rate of basilar rupture). The rate for intraoperative neural injury (thalamic, forniceal, hypothalamic, and midbrain injuries) was 0.24%. Central nervous system infections occurred in 1.81% of cases, CSF leak in 1.61%, and postoperative intracranial hematomas in 0.81% of cases. The early postoperative mortality rate was 0.21% (6 patients died; 2 of sepsis and 4 of hemorrhage). Another 2 children suffered delayed “sudden death” (one after 25 months and the other after 60 months), caused by acute hydrocephalus due to stoma occlusion. There were no significant differences between series involving pediatric or adult patient populations or series with fewer than 100 or more than 100 patients. All reported deaths were in series involving more than 100 patients.

Conclusions
Endoscopic third ventriculostomy can be regarded as a low-complication procedure, with an overall complication rate of 8.5%, permanent morbidity rate of 2.4%, mortality rate of 0.21%, and delayed “sudden death” rate of 0.07%.
Balloon-assisted Onyx embolization of cerebral single-channel pial arteriovenous fistulas
Authors: Newman C. Benjamin , Hu Yin C. , McDougall Cameron G. , Albuquerque Felipe C. 
Published: June 2011

Object
Pial arteriovenous fistulas (AVFs) of the brain are rare vascular malformations associated with significant risks of hemorrhage and neurological deficit. Depending on their location and high-flow dynamics, these lesions can present treatment challenges for both endovascular and open cerebrovascular surgeons. The authors describe a novel endovascular treatment strategy that was used successfully to treat 2 pediatric patients with a pial AVF, and they discuss the technical nuances specific to their treatment strategy.

Methods
A single-channel high-flow pial AVF was diagnosed in 2 male patients (6 and 17 years of age). Both patients were treated with endovascular flow arrest using a highly conformable balloon followed by Onyx infusion for definitive closure of the fistula.

Results
Neither patient suffered a complication as a result of the procedure. At the 6-month follow-up in both cases, the simple discontinuation of blood flow had resulted in durable obliteration of the fistula and stable or improved neurological function.

Conclusions
Onyx can be delivered successfully into high-flow lesions after flow arrest to allow a minimally invasive and durable treatment for pial AVFs.
Surgical management of tumors producing the thalamopeduncular syndrome of childhood
Authors: Broadway S. Jared , Ogg Robert J. , Scoggins Matthew A. , Sanford Robert , Patay Zoltan , Boop Frederick A. 
Published: June 2011

Object
Thalamopeduncular tumors arise at the junction of the inferior thalamus and cerebral peduncle and present with a common clinical syndrome of progressive spastic hemiparesis. Pathologically, these lesions are usually juvenile pilocytic astrocytomas and are best treated with resection with the intent to cure. The goals of this study are to define a common clinical syndrome produced by thalamopeduncular tumors and to discuss imaging characteristics as well as surgical adjuncts, intraoperative nuances, and postoperative complications relating to the resection of these neoplasms.

Methods
The authors present a retrospective review of their experience with 10 children presenting between 3 and 15 years of age with a thalamopeduncular syndrome. Formal preoperative MR imaging was obtained in all patients, and diffusion tensor (DT) imaging was performed in 9 patients. Postoperative MR imaging was obtained to evaluate the extent of tumor resection. A prospective analysis of clinical outcomes was then conducted by the senior author.

Results
Pilocytic astrocytoma was the pathological diagnosis in 9 cases, and the other was fibrillary astrocytoma. Seven of 9 pilocytic astrocytomas were completely resected. Radical surgery was avoided in 1 child after DT imaging revealed that the corticospinal tract (CST) coursed through the center of the tumor, consistent with the infiltrative nature of fibrillary astrocytoma as identified by stereotactic biopsy. In 8 patients, tractography served as an important adjunct for designing a surgical approach that spared the CST. In 6 cases the CSTs were pushed anterolaterally, making a transsylvian approach a poor choice, as was evidenced by the first patient in the series, who underwent operation prior to the advent of tractography, and who awoke with a dense contralateral hemiparesis. Thus, subsequent patients with this deviation pattern underwent a transcortical approach via the middle temporal gyrus. One patient exhibited medial deviation of the tracts and another had lateral deviation, facilitating a transtemporal and a transfrontal approach, respectively.

Conclusions
The thalamopeduncular syndrome of progressive spastic hemiparesis presenting in children with or without symptoms of headache should alert the examiner to the possibility of a tumoral involvement of CSTs. Preoperative tractography is a useful adjunct to surgical planning in tumors that displace motor pathways. Gross-total resection of pilocytic astrocytomas usually results in cure, and therefore should be entertained when developing a treatment strategy for thalamopeduncular tumors of childhood.
Drivers of morphological diversity and distribution in the Hawaiian fern flora: Trait associations with size, growth form, and environment
Authors: Creese Chris , Lee Albert , Sack Lawren 
Published: June 2011

•Premise of the study:Hawaii is home to 238 native and 35 alien fern and lycophyte taxa distributed across steep gradients in elevation and resource availability. The fern flora spans a wide range of growth forms, with extraordinary diversity in morphology and plant size. Yet the potential factors underlying this diversity have remained enigmatic.•Methods:We used a trait database generated from the most recent and comprehensive survey of Hawaiian ferns and lycophytes to test hypotheses of size‐scaling and trait associations with environment and growth form as factors underlying this diversity. We also tested relationships among morphology, taxon abundance and distribution and identified key differences between native and alien taxa.•Key results:Strong trait–trait relationships included geometric scaling of plant dimensions with a tendency for more divided fronds in larger ferns. Trait–environment relationships independent of size included more divided fronds at higher elevation, longer blades in shaded habitats, and fronds with shorter stipes and fewer pinnae in drier habitats. Growth forms differed in mean size with epiphytic and epipetric taxa smaller than terrestrial ferns. Plant size was independent of taxon abundance and distribution across islands, and native and alien ferns did not differ in mean size. Alien taxa were more abundant, especially at lower elevations, apparently due to human land use.•Conclusions:These relationships point to linkages of fern form and demography with biogeography and highlight potential flora‐scale physiological and morphological adaptations in ferns across contrasting environments.
Patterns of hybridization between diploid and derived allotetraploid species ofDactylorhiza(Orchidaceae) co‐occurring in Belgium
Authors: De Hert Koen , Jacquemyn Hans , Van Glabeke Sabine , Roldán‐Ruiz Isabel , Vandepitte Katrien , Leus Leen , Honnay Olivier 
Published: June 2011

•Premise of the study: Although the potential for gene flow between species with large differences in chromosome numbers has long been recognized, only few studies have thoroughly investigated in situ hybridization across taxa with different ploidy levels. We combined morphological, cytological, and genetic marker data with pollination experiments to investigate the degree, direction, and spatial pattern of hybridization between the diploidDactylorhiza incarnataand its tetraploid derivative,D. praetermissa.•Methods: To identify hybrids, 169 individuals were genotyped using AFLPs and morphologically characterized. Individuals were clustered on the basis of their AFLP profile using the program Structure. To reduce the dimensionality of the plant‐trait matrix, PCA was applied. The origin of suspected hybrid individuals was verified using flow cytometry. An AMOVA and spatial autocorrelation analysis were used to indirectly infer the extent of gene flow.•Key results: Only five individuals were regarded as putative hybrids on the basis of the AFLP data; all had been assigned to theD. praetermissamorphotype. Only one had deviating DNA content and was presumably a triploid. High ΦSTvalues between different subpopulations and significant spatial genetic structure were observed, suggesting localized gene flow.•Conclusions: Using combined data to study hybridization betweenD. incarnataandD. praetermissa, very few unequivocal hybrids were observed. We propose several non‐mutually exclusive explanations. Localized pollen flow, in combination with different microhabitat preferences, is probably one of the reasons for the low frequency of hybrids. Also, the triploid first‐generation hybrids may experience difficulties in successful establishment, as a result of genic incompatibilities.
Selection on seedling emergence timing and size in an annual plant, Helianthus annuus (common sunflower, Asteraceae)
Authors: Mercer Kristin L. , Alexander Helen M. , Snow Allison A. 
Published: June 2011

• Premise: Variation in seedling emergence timing is considered adaptive over the long term in wild populations, but early emergence can result in a fitness advantage. To explore the adaptive significance of seedling emergence timing, it should be studied under realistic conditions and in the context of other traits that influence fitness.• Methods: In a common garden, we monitored maternal families from seed to flowering (including over winter) with intra‐ and interspecific competition. We assessed the effects of emergence timing and plant size on survival to anthesis in different genetic backgrounds and under varying competition.• Key Results: We found genetic variation for emergence (probability and timing), size, and survival to anthesis. We also found negative selection, both phenotypic and genetic, on emergence time, such that early emergers (day 8) had almost twice as great a predicted probability of surviving as later emergers (day 28). Size had strong positive effects on survival and, furthermore, the beneficial effects of early emergence may be mediated through size. Maternal family and competitive environment can also affect selection on emergence timing.• Conclusions: Our results indicate that early emergence is related to greater survival in wild sunflower, although there may be little direct selection on this trait; rather, its importance may be mediated by its effects on highly adaptive traits associated with size. Also, the effects of early emergence may vary across genetic backgrounds and competitive conditions, facilitating the maintenance of variation for this trait across a diverse landscape.
Prolonged Duration of Peritoneal Dialysis Catheter Embedment Does not Lower the Catheter Success Rate
Authors: Elhassan Elwaleed , McNair Bryan , Quinn Maggie , Teitelbaum Isaac 
Published: June 2011

Objective Since 2000, we have used the Moncrief–Popovich technique as our standard method for peritoneal dialysis (PD) catheter insertion. The subcutaneous portion of the catheter is externalized immediately before initiation of PD. We undertook the present review to investigate whether duration of catheter embedment affects catheter or patient outcome. Methods All catheters inserted beginning 1 January 2000 and externalized by 31 December 2008 were included. The primary outcome was catheter survival. Secondary outcomes were catheter patency (no fibrin plug or omental wrap) and complications within 90 days after externalization. A standard peritoneal equilibration test was used to classify peritoneal membrane transport status. Proportional hazards regression models were used to test whether duration of embedment affected catheter outcomes. The models treated embedment duration as both a continuous predictor and a categorical predictor categorized by tertile. Results A total of 134 catheters were implanted and externalized. Twelve patients received 2 catheters each. To ensure statistical independence of the observations, 12 of the latter 24 catheters were excluded (1 chosen randomly from each patient), resulting in a useable sample size of 122 catheters. The total duration of observation was 2359 patient–months. The median duration of catheter embedment was 40.5 days (range: 2 – 788 days). After controlling for sex, race, age, and diabetes status, embedment duration did not have a significant effect on catheter survival as a continuous predictor or as a categorical predictor. Additionally, the 95% confidence interval for the 30-day effect of embedment duration ruled out a change of more than 20.6% in the hazard of catheter malfunction or infection. Of the studied catheters, 89.3% were patent and functioned properly immediately upon externalization. The remaining 13 catheters (10.7%) lacked patency on externalization because of fibrin plug or kinking ( n = 10) or omental wrap ( n = 3); however, 12 of the 13 non-patent catheters were corrected laparoscopically, and the patients resumed PD. Only 1 patient transferred to hemodialysis. Overall, 121 of 122 buried catheters (99.2%) were used for PD. Other complications within 90 days of catheter externalization included incision site and tunnel infection in 2 cases (1.6%), exit-site leak in 2 cases (1.6%), and coagulase-negative staphylococcal peritonitis in 1 case (0.8%). Conclusions Duration of catheter embedment before externalization did not affect catheter survival and did not influence subsequent peritoneal membrane transport status. The overall effect of increasing embedment duration by 30 days is, at most, a 20.6% increase or decrease in the hazard of catheter failure, but the actual hazard may be much smaller or nonexistent. Larger studies are needed to further explore the ideal duration of embedment.