bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cerebrospinal fluid shunt infections in children over a 13-year period: anaerobic cultures and comparison of clinical signs of infection with Propionibacterium acnes and with other bacteria
Authors: Arnell Kai , Cesarini Kristina , Lagerqvist-Widh Angela , Wester Tomas , Sjölin Jan 
Published: April 2008

Object
Shunt infections represent a major problem with risk for sequelae and even death. The aim in this retrospective study was to analyze the incidence, origin, and clinical presentation of shunt infections, with special reference to the results of cultures for anaerobic organisms performed in addition to the usual tests, to prolonged incubation times, and to infections caused by Propionibacterium acnes.

Methods
The medical records of 237 hydrocephalic children (age range 0–15 years) in whom operations were performed by a pediatric surgeon at Uppsala University Hospital during a 13-year period were reviewed.

Results
Thirty-four verified or suspected intraventricular shunt infections and 5 distal catheter infections occurred after 474 operations. Skin bacteria, such as coagulase-negative staphylococci ([CoNS], 19 patients), Staphylococcus aureus (7 patients), and P. acnes (6 patients) predominated. The addition of anaerobic cultures and prolonged incubation times increased the verification of shunt infection by more than one third. Children with P. acnes infection were significantly older, had a lower body temperature, fewer cerebrospinal fluid (CSF) leukocytes, a higher CSF/blood glucose ratio, more distal catheter infections, and other sources of infection. Four had an abdominal pseudocyst. Children < 1 year of age and infected with CoNS were more affected than older children with systemic and local symptoms. In children with distal catheter infection and growth of propionibacteria at the time of the distal catheter and valve replacement, no follow-up antibiotic treatment was necessary.

Conclusions
Addition of anaerobic cultures and prolonged incubation times led to an increase in the detection of shunt infections. Infections caused by propionibacteria often result in mild symptoms that may be overlooked if adequate anaerobic cultures are not obtained.
Chemotherapy administration directly into the fourth ventricle in a new piglet model
Authors: Sandberg David I. , Crandall Kenneth M. , Petito Carol K. , Padgett Kyle R. , Landrum John , Babino Darwin , He Danshe , Solano Juan , Gonzalez-Brito Manuel , Kuluz John W. 
Published: April 2008

Object
The authors hypothesized that chemotherapy infusions directly into the fourth ventricle may potentially play a role in treating malignant posterior fossa tumors. In this study the safety and pharmacokinetics of etoposide administration into the fourth ventricle was tested using an indwelling catheter in piglets.

Methods
A closed-tip silicone lumbar drain catheter was inserted into the fourth ventricle via a posterior fossa craniectomy and 5 daily infusions of etoposide (0.5 mg in 5 animals) or normal saline (in 2 animals) were instilled. Piglets (10–18 kg, 2–3 months of age) underwent daily neurological examinations and 4.7-T magnetic resonance (MR) imaging after the final infusion and were then killed for postmortem examination. Pharmacokinetics were studied using reversed-phase high-performance liquid chromatography on cerebrospinal fluid (CSF) samples at 0.25, 1, 2, 4, 8, 12, and 24 hours after etoposide infusion. Peak and trough CSF etoposide levels were measured for each subsequent infusion. Serum etoposide levels were obtained at 2 and 4 hours after infusion.

Results
All piglets remained neurologically intact, and MR images demonstrated catheter placement within the fourth ventricle without signal changes in the brainstem or cerebellum. Serum etoposide was absent at 2 and 4 hours after intraventricular infusions. When adequate samples could be obtained for analysis, CSF etoposide levels peaked 15 minutes after infusion and progressively decreased. Cytotoxic levels (> 0.1 μg/ml) were maintained for 5 consecutive peak and trough measurements with 1 exception. Etoposide-related neuropathology included moderate-to-severe T-lymphocytic meningitis and fourth and lateral ventricular choroid plexitis with associated subependymal inflammation.

Conclusions
Etoposide can be infused directly into the fourth ventricle without clinical or imaging evidence of damage. Cytotoxic CSF etoposide levels can be maintained for 24 hours with a single daily infusion into the fourth ventricle using an indwelling catheter. Intraventricular etoposide elicits an inflammatory response, the long-term effects of which are as yet undetermined.
Anterior debridement and fusion followed by posterior pedicle screw fixation in pyogenic spondylodiscitis: autologous iliac bone strut versus cage
Authors: Pee Yong Hun , Park Jong Dae , Choi Young-Geun , Lee Sang-Ho 
Published: April 2008

ObjectAn anterior approach for debridement and fusion with autologous bone graft has been recommended as the gold standard for surgical treatment of pyogenic spondylodiscitis. The use of anterior foreign body implants at the site of active infection is still a challenging procedure for spine surgeons. Several authors have recently introduced anterior grafting with titanium mesh cages instead of autologous bone strut in the treatment of spondylodiscitis. The authors present their experience of anterior fusion with 3 types of cages followed by posterior pedicle screw fixation. They also compare their results with the use of autologous iliac bone strut.MethodsThe authors retrospectively reviewed the cases of 60 patients with pyogenic spondylodiscitis treated by anterior debridement between January 2003 and April 2005. Fusion using either cages or iliac bone struts was performed during the same course of anesthesia followed by posterior fixation. Twenty-three patients underwent fusion with autologous iliac bone strut, and 37 patients underwent fusion with 1 of the 3 types of cages.ResultsThe infections resolved in all patients, as noted by normalization of their erythrocyte sedimentation rates and C-reactive protein levels. Patients in both groups were evaluated in terms of their preoperative and postoperative clinical and imaging findings.ConclusionsSingle-stage anterior debridement and cage fusion followed by posterior pedicle screw fixation can be effective in the treatment of pyogenic spondylodiscitis. There was no difference in clinical and imaging outcomes between the strut group and cage group except for the subsidence rate. The subsidence rate was higher in the strut group than in the cage group. The duration until subsidence was also shorter in the strut group than in the cage group.
Factors associated with cervical instability requiring fusion after cervical laminectomy for intradural tumor resection
Authors: Sciubba Daniel M. , Chaichana Kaisorn L. , Woodworth Graeme F. , McGirt Matthew J. , Gokaslan Ziya L. , Jallo George I. 
Published: April 2008

ObjectThe indications remain unclear for fusion at the time of cervical laminectomy for intradural tumor resection. To identify patients who may benefit from initial fusion, the authors assessed clinical, radiological/imaging, and operative factors associated with subsequent symptomatic cervical instability requiring fusion after cervical laminectomy for intradural tumor resection.MethodsThe authors reviewed 10 years of data obtained in patients who underwent cervical laminectomy without fusion for intradural tumor resection and who had normal spinal stability and alignment preoperatively. The association of pre- and intraoperative variables with the subsequent need for fusion for progressive symptomatic cervical instability was assessed using logistic regression analysis, and percentages were compared using Fisher exact tests when appropriate.ResultsThirty-two patients (mean age 41 ± 17 years) underwent cervical laminectomy without fusion for resection of an intradural tumor (18 intramedullary and 14 extramedullary). Each increasing number of laminectomies performed was associated with a 3.1-fold increase in the likelihood of subsequent vertebral instability (odds ratio 3.114, 95% confidence interval 1.207–8.034, p = 0.02). At a mean follow-up interval of 25.2 months, 33% (4 of 12) of the patients who had undergone a ≥ 3-level laminectomy required subsequent fusion compared with 5% (1 of 20) who had undergone a ≤ 2-level laminectomy (p = 0.03). Four (36%) of 11 patients initially presenting with myelopathic motor disturbance required subsequent fusion compared with 1 (5%) of 21 presenting initially with myelopathic sensory or radicular symptoms (p = 0.02). Age, the presence of a syrinx, intramedullary tumor, C-2 laminectomy, C-7 laminectomy, and laminoplasty were not associated with subsequent symptomatic instability requiring fusion.ConclusionsIn the authors' experience with intradural cervical tumor resection, patients presenting with myelopathic motor symptoms or those undergoing a ≥ 3-level cervical laminectomy had an increased likelihood of developing subsequent symptomatic instability requiring fusion. A ≥ 3-level laminectomy with myelopathic motor symptoms may herald patients most likely to benefit from cervical fusion at the time of tumor resection.
Disseminated intraspinal hydatid disease
Authors: Moharamzad Yashar , Kharazi Homayoun Hadizadeh , Shobeiri Elham , Farzanegan Gholamreza , Hashemi Forough , Namavari Abed 
Published: April 2008

✓Spinal echinococcosis is a rare entity, accounting for 1% of all cases of hydatid disease. The authors report the case of a 60-year-old man whom they treated for recurrent nerve root compression due to disseminated intraspinal echinococcosis (hydatid disease). Six years previously he had undergone surgery on an emergency basis at another institution after presenting with acute paraplegia due to a primary extradural hydatid cyst of the thoracic spine. Unfortunately, during surgical removal of the cysts, the echinococcosis disseminated into the spinal canal. This complication was documented by magnetic resonance (MR) imaging. In the 4 years before the authors treated him, he was hospitalized 4 times for 4 recurrences of nerve root compression.
The authors treated the disseminated disease successfully with total T7–8 corpectomy, grafting with titanium cage and Texas Scottish Rite Hospital instrumentation, and long-term administration of albendazole (400 mg daily). Early diagnosis, proper utilization of MR imaging, and radical resection of diseased vertebrae and soft tissues followed by anthelmintic treatment are essential to control disseminated spinal hydatidosis and prevent recurrence.
Combinatorial development of polymer nanocomposites using transient processing conditions in twin screw extrusion
Authors: Kota Arun K. , Murphy Larry , Strohmer Timo , Bigio David I. , Bruck Hugh A. , Powell Dan 
Published: April 2008

AbstractA new approach is presented for combinatorial development of polymer nanocomposites with compositional gradients (CGs). The CGs were developed using transient processing conditions in twin screw extrusion with small quantities of expensive nanoscale fillers. Convolution of step input with normalized residence volume distributions (RVDs) was used to establish the processing–structure relationship for the CGs. The normalized RVD was established as a process characteristic independent of processing conditions and measured in situ using an optical probe. The CG determined nondestructively using the new combinatorial approach was validated through comparison with more time‐consuming and destructive thermogravimetric analysis. The CG could also be established with relatively inexpensive microscale fillers using the normalized RVD obtained with nanoscale fillers, suggesting that transient effects of the mixing process are independent of the size of the filler. Finally, structure–property relationship of combinatorially developed polymer nanocomposites was established by characterizing their dynamic mechanical behavior (storage modulus, G′, and loss modulus, G″). The dynamic mechanical behavior of the combinatorially developed composites correlated well with the batch‐processed ones, indicating that the transient mixing conditions in extrusion do not affect the material properties. © 2008 American Institute of Chemical Engineers AIChE J, 2008
The mtDNA ancestry of admixed Colombian populations
Authors: Salas A. , Acosta A. , Álvarez‐Iglesias V. , Cerezo M. , Phillips C. , Lareu M. V. , Carracedo Á. 
Published: April 2008

AbstractA total of 185 individuals from Colombia were sequenced for the first hypervariable region (HVS‐I) of the mitochondrial DNA (mtDNA) genome, and a subset of these individuals were additionally genotyped for the second hypervariable segment (HVS‐II). These individuals were collected according to their “self‐reported ethnicity” in Colombia, comprising “Mestizos,” “Mulatos,“ and “Afro‐Colombians.” We used databases containing more than 4,300 Native American lineages, 6,800 Africans, and 15,600 Europeans for population comparisons and phylogeographic inferences. We observe that Mulatos and Afro‐Colombians have a dominant African mtDNA component, whereas Mestizos carry predominantly Native American haplotypes. All the populations analyzed have high diversity indices and there are no signatures of dramatic genetic drift episodes. Central and South America are the main candidate source populations of the Colombian Native American lineages, whereas west‐central, southwest, and southeast Africa are the main original mtDNA sources for the African Colombian mtDNAs. We found that our results differ from those obtained in other studies for the same “population groups” in terms of haplogroup frequencies. This observation leads us to conclude that (i) self‐reported ancestry is not a reliable proxy to indicate an individual's “ethinicity” in Colombia, (ii) our results do not support the use of outmoded race descriptions (Mestizos, Mulatos, etc.) mainly because these labels do not correspond to any genetically homogeneous population group, and (iii) studies relying on these terms to describe the population group of the individual, which then treat them as genetically homogeneous, carry a high risk of type I error (false positives) in medical studies in this country and of misinterpretation of the frequency of observed variation in forensic casework. Am. J. Hum. Biol. 20:584–591, 2008. © 2008 Wiley‐Liss, Inc.
Discrepant DNA analysis in three patients with inherited arrhythmia: Molecular genetic test results deserve a second glance
Authors: Honeywell Christina R. , Gollob Michael H. , Rutberg Julie , Gow Robert M. , Geraghty Michael T. 
Published: April 2008

AbstractMolecular results provide a basis for diagnosis, risk assessment, medical management and genetic counseling. Unlike other areas of laboratory medicine, molecular genetic tests are rarely repeated. We describe three patients with suspected inherited arrhythmia in whom genetic testing was arranged via clinical and/or research laboratories. In all three instances, initial test results appeared falsely negative, with no deleterious mutations detected by various methodologies in selected long‐QT or catecholaminergic polymorphic ventricular tachycardia‐related genes. Discordant results emerged upon repeat analysis in separate laboratories. The cases highlight the importance of clinical judgment and assessment of genetic test results and methodology, in addition to the role of re‐testing in molecular genetic medicine, particularly in the case of uninformative negative results. © 2008 Wiley‐Liss, Inc.
Genome‐wide scan in 124 Indonesian sib‐pair families with schizophrenia reveals genome‐wide significant linkage to a locus on chromosome 3p26‐21
Authors: Irmansyah  , Schwab S.G. , Heriani  , Handoko H.Y. , Kusumawardhani A. , Widyawati I. , Amir N. , Nasrun M.W.S. , Holmans P. , Knapp M. , Wildenauer D.B. 
Published: April 2008

AbstractVariation in incidence of schizophrenia between populations with different ethnical background may reflect population specific differences in nature and composition of genetic and environmental factors. In order to investigate whether there are population specific susceptibility genes for schizophrenia, we collected in Indonesia families with two or more affected siblings and, as far as available, parents and unaffected siblings, suitable for genetic linkage‐ and association studies. After checking extensively for incompatibilities with Mendelian inheritance as well as for errors in sampling, we used 124 families from the sample of 152 originally ascertained families for linkage analysis. Genotyping was performed at the NHLBI Mammalian Genotyping Service at Marshfield Research Organisation using the Screening Set 16, which comprises 402 Short Tandem Repeat Polymorphisms (STRPs). The genotypes of 540 individuals including 267 affected with schizophrenia were used for analysis. Multipoint sib‐pair linkage analysis was carried out by estimation of—allele sharing derived—maximum likelihood LOD scores (MLS) in 154 sib‐pair combinations. We obtained a genome‐wide significant MLS of 3.76 on chromosome 3p26.2‐25.3. Genome‐wide significance was estimated by performing 10,000 simulated genomescans. Additional loci were detected on 1p12, which produced suggestive evidence for linkage (MLS = 2.35), as well as on 5q14.1 (MLS = 1.56), 5q33.3 (MLS = 1.11), and 10q (MLS = 1.17), where linkage had been reported previously. In conclusion, our study detected a region with genome‐wide significant linkage, which will serve as starting point for identification of schizophrenia susceptibility genes in the Indonesian population. © 2008 Wiley‐Liss, Inc.
The role of rubber characteristics in preparing rubber/clay nanocomposites by melt compounding
Authors: Ma Yong , Wu You‐Ping , Zhang Li‐Qun , Li Qi‐Fang 
Published: April 2008

AbstractRubber/organic clay (OC) nanocomposites were produced by melt blending. Polar or unsaturated matrices (e.g., NBR and SBR) could easily enter into OC layers, whereas using nonpolar unsaturated rubber (EPDM), without other additives' help, intercalation structure could not be directly obtained. For the EPDM system, an intercalated structure was observed in presence of stearic acid (SA) for composites composed of SA and OC. Transmission electron microscopy observation showed that the dispersion of clay in nonpolar saturated rubber matrix was much poorer than that in polar or unsaturated matrix. The same effect of polar matrix was confirmed by comparison between IIR/OC and BIIR/OC systems. Moreover, using OC pretreated by SA (S‐OC), the dispersion of clay was obviously improved in the investigated nanocomposites, due to the intercalation of SA into OC interlayers. Especially in the nonpolar saturated EPDM system, the intercalation structure could be easily observed. Relative to the corresponding nanocomposites using OC, tensile strengths and the stresses at low strain of NBR and SBR based nanocomposites with S‐OC were significantly improved; while with EPDM nanocomposite, using S‐OC, only tensile strengths were improved but the stresses at low strain were almost the same, which should be related to the different interfacial force between OC and different rubber matrices. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and evaluation of two kinds of solid polymer electrolytes made from crosslinked poly(ether urethane) elastomers consisting of a comb‐like and a hyperbranched polyether
Authors: Ye Lin , Gao Peng , Zhao Yu‐mei , Feng Zeng‐guo , Bai Ying , Wu Feng 
Published: April 2008

AbstractTwo novel polyethers, one comb‐like and another hyperbranched, were synthesized by the cationic ring‐opening polymerization of 3‐(methoxy(triethylenoxy))methyl‐ and 3‐(hydroxy‐(triethylenoxy))methyl‐3′‐methyloxetane, respectively. The former reacted with a multifunctional isocyanate and the latter with a difunctional isocyanate to give rise to the corresponding crosslinked poly(ether urethane) elastomers, PCEU and PHEU. Accordingly, two kinds of solid polymer electrolytes (SPEs) were prepared from these two elastomers in situ in the presence of lithium salt trifluoromethanesulfonimide. It was found that the PCEU‐based SPEs shows a higher ionic conductivity than that PHEU‐based ones due to its more mobile pendent chains and appropriate crosslinking density in the polymeric network. The maximum ionic conductivities of 1.4 × 10−5 S/cm at 30°C and 3.5 × 10−4 S/cm at 80°C were attained at the molar ratio of O/Li = 7.5. The DSC measurements clearly demonstrated that PCEU indeed possesses the more flexible chain motion ability than PHEU. The electrochemical stability window of PCEU, which is 1.7–4.0 V was measured by cyclic voltammogram. Additionally, the significantly high decomposition temperature as evidenced by TGA analyses endowed these SPEs a good safe performance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Rate transitions in the fatigue crack growth of elastomers
Authors: Papadopoulos I. C. , Thomas A. G. , Busfield J. J. C. 
Published: April 2008

AbstractIt has been observed previously that cracks in elastomers under repeated strain initially grow rapidly from sharp cuts, but as the cracks proceed, the rate decreases to a steady value. This work examines these transitions from a sharp crack tip, introduced by a razor blade into a pure shear test piece, for a range of elastomers. The changes in the rate of crack growth are also reflected by changes in the fracture surface appearance, which roughens as the crack develops. This phenomenon is of practical significance in engineering applications, in which an initially fast crack growth rate from a sharp cut in a rubber product can result in significantly lower fatigue life than anticipated from the steady‐state value, which is usually presented and quoted. The change in the rate with the number of cycles can be represented by an empirical relation whose parameters are functions of the strain energy release rate. The roughening of the crack can be envisioned as the splitting of a sharp tip into several tips with a consequent sharing of the strain energy release rate between them, leading to a reduction in the crack growth rates. This representation of the roughening process has been analyzed with a FEA approach. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of pH on the specific surface area of polyaniline matrices
Authors: Chowdhury Al‐Nakib , Saleh Farhana Sultana , Rahman Mohammad Rezaur , Rahim Abdur 
Published: April 2008

AbstractWe report the successful measurement of the specific surface area of chemically synthesized and treated polyaniline (PANI) and its composite PANI/silica (SiO2). PANI was synthesized chemically from an aqueous solution of aniline and hydrochloric acid (HCl) in the presence of an oxidant, ammonium peroxydisulfate [(NH4)2S2O8]. In the synthesis of PANI/SiO2, SiO2 was incorporated from its colloidal solution contained in the solution for the polymerization of PANI. PANI and PANI/SiO2 thus synthesized were pretreated with double‐distilled water (pH = 6.95), aqueous HCl (pH = 1.09), and aqueous ammonia (pH = 10.15) solutions to control their pH levels. Surface morphologies of the treated PANI and PANI/SiO2 matrices were investigated with scanning electron microscopy. The successful incorporation of SiO2 into the PANI/SiO2 composite was confirmed by the characteristic infrared absorption band at 1096 cm−1. The adsorption of methylene blue, which was found to follow the Langmuir isotherm, onto the prepared materials was probed to estimate the real surface area. The base‐treated PANI matrix showed a higher surface area than the acidic and neutral ones. The incorporation of SiO2 into the PANI matrix yielded a larger surface area. However, the treated PANI/SiO2 showed the same trend as the treated PANI matrices. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008