bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of clinical, MRI and multimodality evoked potentials in neurologic Wilson disease
Authors: Das M. , Misra U. K. , Kalita J.
Published: April 2007

The aims of this study were evaluate motor, somatosensory, visual and auditory brainstem evoked potential (MEP, SEP, VEP, ABER) changes in Wilson disease (WD) and correlate these with magnetic resonance imaging (MRI) and clinical findings.

Neurologic WD diagnosed on the basis of clinical, ceruloplasmin and Kayser–Fleischer ring were evaluated including pedigree charting, hepatic, renal, hematologic and osteoarticular manifestations. Blood counts, serum chemistry, MRI, MEP to tibialis anterior, tibial SEP, VEP and ABER were performed. Evoked potential (EP) changes were correlated with clinical and MRI findings.

Eighteen WD patients were recruited from 17 families whose mean age was 16 years. Movement disorders were present in 14, cognitive decline in 12 and pyramidal signs in 12 patients. MRI revealed involvement of basal ganglia in 80%, thalamus in 40%, brain stem in 46.7% and subcortical white matter in 53.3%. MEP was abnormal in 35.7%, SEP in 30.8%, VEP in 57% and ABER in 61.5% patients; the latter three EP changes were subclinical. Frequency and number of EP abnormalities were higher with increasing severity of illness.

SEP, VEP and ABER reveals subclinical abnormality and MEP helps in documenting both clinical and subclinical abnormalities. Number of EP abnormalities increases with increasing clinical severity of WD.
Education and training of European neurologists in dementia
Authors: Hasselbalch S. G. , Baloyannis S. , Denislic M. , Dubois B. , Oertel W. , Rossor M. , Tsiskaridze A. , Waldemar G.
Published: April 2007

The aim of this study was to describe the present involvement of neurologists in dementia management in European countries. Data were obtained from a questionnaire that members of The European Federation of Neurological Societies Scientific Panel on Dementia responded to. Information was obtained from 25 countries in Europe. A progressive decrease in the teaching activity from medical school to board‐certified neurologists was reported. Teaching of medical students in dementia is obligatory in most countries, whereas there is no formal obligatory education in dementia after graduation from medical school. Further, in only half of the countries that responded to the questionnaire, obligatory courses in dementia are part of the training in neurology. Except for one country, the post‐graduate training programs of board‐certified neurologists do not include dementia as an obligatory topic. In only 10 of 25 countries, guidelines for neurologists on dementia evaluation have been published in local language. It is recommended to include obligatory teaching and training in dementia in the catalogue of minimum requirements for specialist training in neurology and this teaching should also be part of the ongoing update of certified neurologists.
Cognitive dysfunction and hypogonadotrophic hypogonadism in a Brazilian patient with mitochondrial neurogastrointestinal encephalomyopathy and a novel ECGF1 mutation
Authors: Carod‐Artal F. J. , Herrero M. D. , Lara M. C. , López‐Gallardo E. , Ruiz‐Pesini E. , Martí R. , Montoya J.
Published: April 2007

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is caused by mutations in the thymidine phosphorylase gene (ECGF1). We present the first detailed report of a Brazilian MNGIE patient, harboring a novel ECGF1 homozygous mutation (C4202A, leading to a premature stop codon, S471X). Multiple deletions and the T5814C change were found in mitochondrial DNA. Together with gastrointestinal symptoms, endocrine involvement and memory dysfunction, not reported in MNGIE to date, were the most preeminent features.
Cerebral blood flow in patients with diffuse axonal injury – examination of the easy Z‐score imaging system utility
Authors: Okamoto T. , Hashimoto K. , Aoki S. , Ohashi M.
Published: April 2007

To evaluate the utility of easy Z‐score imaging system (eZIS) in 27 diffuse axonal injury (DAI) cases. Twenty‐seven DAI patients were examined with an magnetic resonance imaging (MRI) T2* sequence and with eZIS (seven women, 20 men; age range, 19–35 years; median age: 26.6 years). In this investigation, we excluded patients who exhibited complications such as acute subdural hematoma, acute epidural hematoma, intracerebral hematoma, or brain contusion. We examined the neuropsychological tests and correlated with findings from MRI/eZIS. Furthermore, we evaluated the degree of ventricular enlargement in the bifrontal cerebroventricular index (CVI). Patients were divided into two groups: the enlargement group (bifrontal CVI > 35%, 12 patients) and the non‐enlargement group (bifrontal CVI < 35%, 15 patients). All of the patients showed cognitive deficits as observed from the neuropsycological test results. Fifteen out of 27 patients by MRI T1/T2 weighted images and fluid attenuated inversion recovery (FLAIR), 22 out of 27 patients by MRI T2* weighted images and 24 out of 27 patients by eZIS showed abnormal findings. In MRI T2* weighted imaging, the white matter from the frontal lobe, corpus callosum, and brainstem showed abnormal findings. With eZIS, 22 patients (81.5%) showed blood flow degradation in the frontal lobe, and 12 patients (44.4%) in cingulate gyrus. In the enlargement group, Functional Independence Measure, Mini‐Mental State Examination, Verbal IQ (VIQ)/Full Scale IQ (FIQ), Trail Making Test‐B (TMT‐B), and Non‐paired of Miyake Paired Test were significantly lower. Amongst 12 patients without ventricular enlargement who had no abnormal findings in MRI T1/T2 weighted images and FLAIR, abnormal findings were detectable in seven patients with MRI T2* weighted imaging and to 10 patients with eZIS. Results of the MRI examination alone cannot fully explain DAI frontal lobe dysfunction. However, addition of the eZIS‐assisted analysis derived from the single photon emission computed tomography (SPECT) data enabled us to understand regions where blood flow was decreased, i.e., where neuronal functions conceivably might be reduced.
White matter changes in Leber's hereditary optic neuropathy: MRI findings
Authors: Küker W. , Weir A. , Quaghebeur G. , Palace J.
Published: April 2007

Leber's hereditary optic neuropathy is a mitochondrial disorder causing bilateral optic nerve degeneration. It is sometimes associated with clinical signs of multiple sclerosis. We report MRI findings in two patients with LHON‐MS and comment on possible distinguishing features of this disease entity.
Proteomic identification of potential protein markers in cerebrospinal fluid of GBS patients
Authors: Jin T. , Hu L.‐S. , Chang M. , Wu J. , Winblad B. , Zhu J.
Published: April 2007

Increased protein level in the cerebrospinal fluid (CSF) is a characteristic of patients with Guillain–Barré syndrome (GBS), an acute inflammatory autoimmune disorder in the peripheral nervous system (PNS). However, the molecular mechanisms underlying the disease remain poorly understood and so far no reliable disease‐related markers are available. By comparing the CSF proteome of GBS patients with control subjects suffering from other neurological disorders, it may be possible to identify proteins that involve in the disease process and thus to study the pathogenesis of GBS. We used two‐dimensional difference gel electrophoresis (2D DIGE) technique, in combination with matrix‐assisted laser desorption ionization time of flight mass spectrometry (MALDI‐TOF MS), to determine the abnormal CSF proteins in GBS patients. Our data showed that the levels of six proteins and their isoforms in CSF were significantly altered in GBS patients compared with controls. Haptoglobin, apolipoprotein A‐IV and PRO2044 (unnamed protein) were considerably increased in the CSF of GBS patients, whereas transthyretin, apolipoprotein E and fibrinogen were considerably decreased. We concluded that these six proteins may be involved in the pathogenesis of GBS and call for further studying the role of these proteins in the pathogenesis of the disease.
Use of proteomics for the identification of novel drug targets in brain diseases
Authors: Morón Jose A. , Devi Lakshmi A.
Published: April 2007

In spite of the rapid advances in the development of the new proteomic technologies, there are, to date, relatively fewer studies aiming to explore the neuronal proteome. One of the reasons is the complexity of the brain, which presents high cellular heterogeneity and a unique subcellular compartmentalization. Therefore, tissue fractionation of the brain to enrich proteins of interest will reduce the complexity of the proteomics approach leading to the production of manageable and meaningful results. In this review, general considerations and strategies of proteomics, the advantages and challenges to exploring the neuronal proteome are described and summarized. In addition, this article presents an overview of recent advances of proteomic technologies and shows that proteomics can serve as a valuable tool to globally explore the changes in brain proteome during various disease states. Understanding the molecular basis of brain function will be extremely useful in identifying novel targets for the treatment of brain diseases.
Treatment with IFNαin vivo up‐regulates serum‐soluble TNF‐related apoptosis inducing ligand (sTRAIL) levels and TRAIL mRNA expressions in neutrophils in chronic myelogenous leukemia patients
Authors: Tanaka Hideo , Ito Takuo , Kyo Taiichi , Kimura Akiro
Published: April 2007

Tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) is an interferon α (IFNα)‐induced, apoptosis‐inducing molecule. TRAIL could be one of the reagents for therapeutic use in combination with imatinib in chronic myeloid leukemia (CML). Here we examined serum‐soluble TRAIL (sTRAIL) levels in CML patients either before or during therapies with IFNα or imatinib. In untreated CML patients, serum sTRAIL was detectable and the levels were substantially comparable with those in healthy donors. sTRAIL levels significantly increased in patients during IFNα therapy, but not at all in patients during imatinib therapy. TRAIL mRNA expressions in neutrophils in CML patients undergoing IFNα therapy was significantly elevated when compared with those in patients prior to therapy. TRAIL mRNA expressions were also detectable in CD34‐positive cells in bone marrow, and the levels increased in patients during IFNα therapy. In vitro IFNα stimulation of CML neutrophils increased intracellular TRAIL rather than cell‐surface TRAIL, and the secretion of sTRAIL in the culture supernatant was observed. This sTRAIL secretion was augmented with lipopolysaccharide (LPS) stimulation only in IFNα‐primed neutrophils, whereas LPS alone had no effect. Taken together, in vivo IFNα treatment provokes the release of sTRAIL when administered systematically in CML patients. The main source of the IFNα‐induced serum sTRAIL may be neutrophils in CML, and sTRAIL may be one of the mechanisms of the anti‐proliferative action of IFNα on CML. These findings give another rationale for the use of IFNα or recombinant sTRAIL in CML, and also implicate the potential importance of neutrophils in tumor immunosurveillance.
Implant Stability Measurements Using Resonance Frequency Analysis in the Grafted Maxilla: A Cross‐Sectional Pilot Study
Authors: Rasmusson Lars , Stegersjö Göran , Kahnberg Karl‐Erik , Sennerby Lars
Published: April 2007

Background: High failure rates have been presented for implants placed in grafted bone. The bone graft‐implant interface constitutes a most complex healing situation, where the time scale for osseointegration and development of implant stability currently is not known.

Purpose: The aim of the study was to measure the stability of implants placed in grafted bone after various follow‐up periods.

Methods: Implant stability measurements by means of resonance frequency analysis were performed in 10 patients previously treated with a Le Fort I osteotomy and interpositional bone grafts. The implants were placed 3 to 4 months after the grafting procedure. Sixty‐seven Brånemark implants were subjected to resonance frequency analysis measurements at fixture placement and up to 5.5 years after implant surgery. Periapical radiographs were used for assessment of marginal bone levels.

Results: The radiographic examinations showed marginal bone loss with time during the 5.5‐year follow‐up. The resonance frequencies varied from 5860 to 8440 Hz. When accounting for abutment length and marginal bone level, there was a tendency of increasing resonance frequency with time. Two implants with low resonance frequencies failed during the prosthetic phase.

Conclusion: The results indicate an increased implant stability with time, which may reflect bone formation, remodeling, and maturation at the implant interface.
On Cutting Torque Measurements during Implant Placement: A 3‐Year Clinical Prospective Study
Authors: Friberg Bertil , Sennerby Lars , Gröndahl Kerstin , Bergström Christina , Bäck Thomas , Lekholm Ulf
Published: April 2007

Background: Evaluation of jaw bone quality at implant placement is mainly based on preoperative radiographic assessments and subjective hand registrations during implant site preparation. An objective technique with cutting torque measurements has been introduced, presenting an objective bone quality or bone hardness value of individual implant sites.

Purpose: The purpose of this study was to evaluate cutting torque measurements during implant placement and to compare these values in different regions in mandibles and maxillae. The objective was to identify implants at risk for failing at implant placement.

Material and Methods: Cutting torque measurements were performed during placement of Mk II self‐tapping implants (Brånemark System TM) in 105 patients, comprising 72 edentulous (40 maxillae) and 34 partially edentulous (22 maxillae) jaws. A total of 523 implants were inserted, of which 420 were of the Mk II design and of which 412 were subjected to cutting torque measurements. Statistical analyses were performed by comparing cutting torque values of maxillae and mandibles and of different jaw regions. Cutting torque values were also correlated with radiographically and clinically assessed bone quality scores. Patients were followed clinically for a minimum of 3 years.

Results: A statistically significant difference in cutting torque values of maxillae and mandibles was seen, although not when comparing anterior and posterior regions within the same jaws or of different jaws. Significant correlations were found between values of cutting torque and bone quality. The majority of failures were seen in bone of medium to high density, whereas implants inserted in bone of poor density presented a better outcome, perhaps due to an adapted surgical protocol and an extended healing period. The overall implant survival rate at 3 years was 95%, and when analyzing different jaw categories, survival rates of 92.0% and 99.4% were seen for edentulous maxillae and mandibles, respectively. The corresponding figures for partially edentulous jaws were 95.4% and 97.6%.

Conclusion: It was not possible to identify sites at risk for future implant losses or to determine a lower limit value of cutting torque in order to achieve successful implant integration.
Implant Treatment of Posterior Mandibular Sextants
Authors: Martinez Henry , Davarpanah Mithridade , Celletti Renato , Missika Patrick
Published: April 2007

In mandibular posterior sextants an insufficient bone quality or volume may contraindicate implant placement. Crestal bone resorption, supra‐eruption of teeth, and minimal bone coronal to the mandibular canal are the principal reasons for not placing dental implants. The available prosthetic space is also a major factor in determining surgical and prosthetic treatment. Various surgical approaches are used to create adequate bone volume in the posterior mandible, thereby allowing the possibility for implant placement. The therapeutic choice is made depending upon residual bone volume and available prosthetic space. The risks and disadvantages of the various techniques must be seriously evaluated and explained to the patient.
Nonsubmerged Implants in the Treatment of the Edentulous Upper Jaw: A Prospective Clinical and Radiographic Study of ITI Implants—Results after 1 Year
Authors: Åstrand Per , Anzén Bengt , Karlsson Ulf , Sahlholm Sten , Svärdström Pia , Hellem Sölve
Published: April 2007

Background:

A new generation of ITI implants, including a hollow cylinder, a hollow screw, and a solid screw, was described in 1988. Currently, the solid screw is the main alternative.

Purpose:

The aim of this study was to gain further clinical documentation of ITI solid‐screw implants used in the edentulous upper jaw. This is a report 1 year after loading.

Materials and Methods:

Twenty‐eight patients with edentulous upper jaws (mean age, 57 yr) were supplied with four to eight ITI solid‐screw implants in the upper jaw. In total, 167 implants (3.3 and 4.1 mm in diameter) were inserted. The implants were loaded about 7 months postoperatively. All patients were supplied with fixed screw‐retained bridges.

Results:

Twelve implants failed: 10 prior to loading and 2 after. Overall implant survival rate was 92.8%. Three of the five patients with implant loss were smokers. Signs of peri‐implantitis were found in seven patients, affecting 12 implants. Mean marginal bone level at the loading of the implants (7 months after insertion) was situated 4.7 mm from the reference point of the implant. There was no significant change between loading and the 1‐year examination. However, at several implants, the bone level at baseline was situated far apical of the reference point, indicating a bone loss before loading.

Conclusions:

The ITI screw implants, used in the edentulous upper jaw, had a survival rate of 92.8%. Mean bone loss between loading and the 1‐year examination was 0.1 mm. Some implants had a bone level indicating a significant bone loss before loading. Peri‐implantitis was found at about 7.2% of the implants inserted and at 25% of the failing implants.
Histopathologic Observations on Late Oral Implant Failures
Authors: Esposito Marco , Thomsen Peter , Ericson Lars E. , Sennerby Lars , Lekholm Ulf
Published: April 2007

Background: Despite good success rates of osseointegrated oral implants, failures do occur. To minimize losses, failure mechanisms should be elucidated.

Purpose: This study sought to describe the morphology of tissues surrounding late failed Brånemark implants in relation to their clinical and radiographic findings to acquire a better understanding of the etiologic factors.

Material and Methods: Ten failed implants and their surrounding tissues were consecutively retrieved from nine patients after prosthesis placement (late losses). On radiographs, a radiolucent line was visible around nine clinically mobile implants. Tightening of the abutment screw evoked pain at seven mobile implants. Clinically, no other visual inflammatory sign or symptom was manifest. A fistula originated from one stable implant, surrounded on radiographs by a diffuse bone rarefaction. Retrieved implants were electrochemically dissolved. Intact tissue‐implant thin (1 μm) and ultrathin (70–80 nm) sections were analyzed with light and transmission electron microscopy.

Results: Peri‐implant marginal tissues displayed moderate inflammatory infiltrates located adjacent to and beneath the junctional epithelium. One patient affected by oral lichen planus displayed an intense lymphocyte/plasma cell‐dominated immune reaction. Deep peri‐implant tissues surrounding mobile implants consisted of a dense, fibrous tissue capsule with minimal inflammation. Epithelial downgrowth was observed around four implants. Small areas of nonmineralized bone in contact with the implant were noticed in the apical portion of two implants. One implant was almost entirely colonized by bacterial plaque with the exception of its apical portion, where bone‐implant contact was observed. The stable implant was characterized by bone‐implant contact.

Conclusion: Altogether clinical, radiographic, and histologic findings indicated that two major etiologic factors might have been implicated in the failure process of the investigated implants: excessive occlusal load in relation to the bone‐supporting capacity and, in two cases, infection.
Hydroxyapatite Granule/Carrier Composites Promote New Bone Formation in Cortical Defects
Authors: Liljensten Elisabeth L. , Attaelmanan Atta G. , Larsson Cecilia , Ljusberg‐Wahren Helena , Danielsen Nils , Hirsch Jan‐Michaél , Thomsen Peter
Published: April 2007

Background: A great deal of interest has been focused on finding substitutes for autogenous bone grafts. Among the most interesting materials are different calcium phosphate compositions (e.g., hydroxyapatite [HA]), due to their biocompatible properties in hard and soft tissue.

Purpose: The bone response to porous ceramic HA granules in combination with two lipid and one polysaccharide carrier was evaluated in an experimental bone defect model in rabbits.

Materials and Methods: Circular defects (Ø 4 mm) were made in both tibias of 32 rabbits. The 64 defects were divided into four groups. Group A was augmented with a composite of HA granules and a phospholipid‐diacetyl‐glycerol carrier, group B with HA granules and a phospholipid carrier, group C received HA granules and a sodium hyaluronan carrier, and group D served as control. The animals were killed after 6 weeks annd ground sections were evaluated using light microscopic morphometry. X‐ray microfluorescence (XRF) was applied in order to evaluate the suitability of this method to examine bone‐biomaterial interfaces. Calcium distribution was studied using x‐ray fluorescence line scans at selected interface regions of two sections in group B.

Results: The HA/phospholipid composites were easier to shape and handle than the HA/hyaluronan composite. Group A had 36% newly formed bone area within the defect. Groups B and C showed significantly more newly formed bone within the defect (47% and 49%, respectively) compared to the control group (31%). The XRF analysis revealed that the amount of calcium in the newly formed bone was similar to that observed for the HA granules and slightly lower when compared to the mature, lamellar bone.

Conclusions: Synchrotron radiation may be a new, suitable technique to study the interface between bone and bio‐materials with regard to mineral content. The results suggest that HA granule/lipid and HA granule/hyaluronan composites have interesting properties as bone‐substitute materials.
Early Functional Loading of Brånemark Dental Implants: 5‐Year Clinical Follow‐up Study
Authors: Ericsson Ingvar , Randow Kjell , Nilner Krister , Peterson Arne
Published: April 2007

Background: Short‐term clinical studies have indicated the possibility of one‐stage surgery and early loading of machined titanium implants. However, long‐term data comparing the outcome to the conventional two‐stage technique are missing.

Purpose: A clinical and radiographic study was performed to compare the outcome of oral rehabilitation of the endentulous mandible by fixed suprastructures connected to implants installed according to either (1) a one‐stage surgical procedure and early loading (experimental group ‐ EG) or (2) the original two‐stage concept (reference group ‐ RG). The EG and RG comprised 16 and 11 subjects, respectively.

Materials and Methods: The following specific inclusion criterion were adopted: (1) all patients had to consider themselves to be in good general health, (2) the amount of bone had to enable the installation of five to six, at least 10‐mm long fixtures (Mk II fixtures; Nobel Biocare AB, Göteborg, Sweden) between the mental foramina, and (3) the patients had to be available for the follow‐up and maintenance program. A total of 88 implants were placed in the EG compared to 30 in the RG. In the EG, fixed appliances were connected to the implants within 20 days following implant installation while the fixed appliances in the RG were connected about 4 months following fixture installation. At delivery of the suprastructures, all patients were radiographically examined, an examination that was repeated at the 18‐ and 60‐month follow‐ups.

Results: The analysis of the radiographs from the EG disclosed that during the observation period, between 18 and 60 months, the mean loss of bone support amounted to 0.2 mm (SD = 0.4). The corresponding value observed in the RG was 0.0 mm (SD = 0.5). During the 60‐month observation period, no fixture was lost in any of the two groups examined. The implants under study as well as those in the reference material were at all observation intervals found to be clinically stable.

Conclusions: This clinical study demonstrated that it is, at least based on a 5‐year observation period, possible to successfully load via a permanent fixed rigid cross‐arch suprastructure titanium dental implants soon after installation. However, such a treatment approach has to be strictly limited to the interforamina area of the endentulous mandible. Furthermore, the bone resorption was found to be within the same range around such implants as around implants installed and loaded according to the original two‐stage protocal.
Immediate and Delayed Implant Placement Into Extraction Sockets: A 5‐Year Report
Authors: Polizzi Giovanni , Grunder Ueli , Goené Ronnie , Hatano Naoki , Henry Patrick , Jackson William J. , Kawamura Kunio , Renouard Franck , Rosenberg Ruben , Triplett Gilbert , Werbitt Marvin , Lithner Berit
Published: April 2007

Background: As a complement to the earlier reported 3‐year results from a prospective multicenter study of immediate and delayed placement of implants into fresh extraction sockets, the 5‐year results are reported.

Purpose: The purpose of this 5‐year report was to evaluate the immediate and long‐term success of implants placed into fresh extraction sockets, with respect to implant size and type, bone quality and quantity, implant position, initial socket depth, and reason for tooth extraction.

Materials and Methods: This paper presents the 5‐year results of the original 12 centers that participated with 143 consecutively included patients. A total of 264 implants were placed either immediately after tooth extraction or after a short soft‐tissue healing time (3–5 weeks). The patients were divided into five subgroups, depending on the type of insertion method used.

Results: The outcome demonstrated that the cumulative implant survival rate after 5 years of loading has not changed and remains 92.4% in the maxilla and 94.7% in the mandible. No difference in failure rates can be seen between the groups when relating the failures to insertion method.

Conclusion: This prospective study demonstrated that placing Brånemark implants into fresh extraction sites can be successful over a period of 5 years of loading. One of the outcomes of the study shows that there is a clinical correlation between implant failure and periodontitis as a reason for tooth extraction, even if it is difficult to give it a casual association. It can be hypothesized that periodontitis affected tissues might have a negative local influence because of the presence of infrabony defects that could possibly increase the gap between bone and implant or jeopardize achievement of primary stability.
Factors Affecting Late Fixture Loss and Marginal Bone Loss Around Teeth and Dental Implants
Authors: Hultin Margareta , Fischer Juhani , Gustafsson Anders , Kallus Thomas , Klinge Bjôrn
Published: April 2007

Background: The predictability and high success rate of implant treatment have averted attention from factors affecting fixture loss and bone loss around implants.

Purpose: The goal of this study was to retrospectively evaluate late fixture loss and marginal bone loss around implants that have been in function for 5 years and to relate these findings to bone loss in the natural dentition.

Materials and Methods: One hundred and forty‐three consecutively treated patients who had received an implantanchored fixed prosthesis and completed a 5‐year follow‐up were selected. Intraoral and panoramic radiographs were used to assess bone loss.

Results: The bone loss was greater around remaining implants in patients who had lost implants after loading. No correlation was found between bone loss around implants and that around teeth. Only 2% of the fixtures were lost during 5 years of functional load. Most fixture losses occurred in the edentulous maxilla. Seven of the nine patients who lost fixtures were smokers.

Conclusion: These findings show that patients who lost implants also lost more bone around the remaining implants. There was no correlation between bone loss around implants and that around teeth, indicating that different interacting mechanisms are involved.
Effects of Implant Design and Surface on Bone Regeneration and Implant Stability: An Experimental Study in the Dog Mandible
Authors: Rasmusson Lars , Kahnberg Karl‐Erik , Tan Albert
Published: April 2007

Background: Previous experimental studies have shown a higher degree of bone‐implant contact for surface‐enlarged implants compared with machined implants. Yet, there is insufficient evidence that such implants show higher stability and an increased survival rate.

Purpose: The purpose of this investigation was to study the integration and stability of grit‐blasted implants with retention elements on the implant neck, with and without marginal bone defects, compared with machined implants without retention elements.

Materials and Methods: After tooth extraction of the mandibular premolars in six dogs, two grit‐blasted, partly microthreaded Astra Tech implants and one standard Branemark implant were bilaterally placed in each dog. On one side, 3 ± 3 mm large buccal defects were created, to expose three to four implant threads. The contralateral side served as control, and no defects were made. The animals were sacrificed after 4 months of healing. Implant stability was measured using resonance frequency analysis at implant installation and after 4 months of healing. Histologic and histomorpho‐metric evaluation was made after 4 months of healing.

Results: Resonance frequency analysis indicated that all implants in the test and control groups were osseointegrated after 4 months, with a tendency toward higher implant stability for the Astra Tech implants. There was a statistically significant higher increase in resonance frequency for the Astra test implants compared with their corresponding controls. Histology and histomorphometry showed well‐integrated implants with varying degrees of bone repair at the defect sites. The greater bone‐implant contact for the Astra implants was statistically significant. No significant difference between the implants in amount of bone filling the threads was recorded.

Conclusions: The Astra Tech implants tested showed a higher degree of bone—implant contact and higher level of bone regenerated at defect sites compared with the Brånemark implants. Resonance frequency analysis demonstrated a significantly higher increase in the Astra test implants compared with their control groups than did the Brånemark test implants versus their controls.
Biochemical and structural characterization of mammalian‐like purine nucleoside phosphorylase from the Archaeon Pyrococcus furiosus
Authors: Cacciapuoti Giovanna , Gorassini Sabrina , Mazzeo Maria Fiorella , Siciliano Rosa Anna , Carbone Virginia , Zappia Vincenzo , Porcelli Marina
Published: April 2007

We report here the characterization of the first mammalian‐like purine nucleoside phosphorylase from the hyperthermophilic archaeon Pyrococcus furiosus (PfPNP). The gene PF0853 encoding PfPNP was cloned and expressed in Escherichia coli and the recombinant protein was purified to homogeneity. PfPNP is a homohexamer of 180 kDa which shows a much higher similarity with 5′‐deoxy‐5′‐methylthioadenosine phosphorylase (MTAP) than with purine nucleoside phosphorylase (PNP) family members. Like human PNP, PfPNP shows an absolute specificity for inosine and guanosine. PfPNP shares 50% identity with MTAP from P. furiosus (PfMTAP). The alignment of the protein sequences of PfPNP and PfMTAP indicates that only four residue changes are able to switch the specificity of PfPNP from a 6‐oxo to a 6‐amino purine nucleoside phosphorylase still maintaining the same overall active site organization. PfPNP is highly thermophilic with an optimum temperature of 120 °C and is characterized by extreme thermodynamic stability (Tm, 110 °C that increases to 120 °C in the presence of 100 mm phosphate), kinetic stability (100% residual activity after 4 h incubation at 100 °C), and remarkable SDS‐resistance. Limited proteolysis indicated that the only proteolytic cleavage site is localized in the C‐terminal region and that the C‐terminal peptide is not necessary for the integrity of the active site. By integrating biochemical methodologies with mass spectrometry we assigned three pairs of intrasubunit disulfide bridges that play a role in the stability of the enzyme against thermal inactivation. The characterization of the thermal properties of the C254S/C256S mutant suggests that the CXC motif in the C‐terminal region may also account for the extreme enzyme thermostability.
Changes in Thermostability of Photosystem II and Leaf Lipid Composition of Rice Mutant with Deficiency of Light‐harvesting Chlorophyll a/b Protein Complexes
Authors: Tang Yunlai , Chen Mei , Xu Yinong , Kuang Tingyun
Published: April 2007

We studied the difference in thermostability of photosystem II (PSII) and leaf lipid composition between a T‐DNA insertion mutant rice (Oryza sativa L.) VG28 and its wild type Zhonghua 11. Native green gel and SDS‐PAGE electro‐phoreses revealed that the mutant VG28 lacked all light‐harvesting chlorophyll a/b protein complexes. Both the mutant and wild type were sensitive to high temperatures, and the maximal efficiency of PSII photochemistry (Fv/ Fm) and oxygen‐evolving activity of PSII in leaves significantly decreased with increasing temperature. However, the PSII activity of the mutant was markedly more sensitive to high temperatures than that of the wild type. Lipid composition analysis showed that the mutant had less phosphatidylglycerol and sulfoquinovosyl diacylglycerol compared with the wild type. Fatty acid analysis revealed that the mutant had an obvious decrease in the content of 16:1t and a marked increase in the content of 18:3 compared with the wild type. The effects of lipid composition and unsaturation of membrane lipids on the thermostability of PSII are discussed.
AtCLH2, a Typical but Possibly Distinctive Chlorophyllase Gene in Arabidopsis
Authors: Liao Yang , An Kun , Zhou Xiao , Chen Wen‐Jun , Kuai Ben‐Ke
Published: April 2007

Chlorophyllase (EC 3.1.1.14) is involved in the first step of chlorophyll degradation. Isolation of chlorophyllase genes greatly facilitates characterization of chlorophyllase properties and elucidation of molecular regulation of their in vivo activities. There are two chlorophyllase genes, AtCLH1 and AtCLH2, in Arabidopsis thaliana. The in vivo roles of AtCLH1 have been reported previously. However, few studies have been carried out on AtCLH2. Here, we show that purified recombinant Chlase2, encoded by AtCLH2, exhibits in vitro chlorophyllase activity. Interestingly, “activation” of in vitro activity of the recombinant Chlase2 required higher concentrations of a detergent or a polar solvent. To determine its activity in vivo, the expression of AtCLH2 was inhibited by RNA interference. RNAi plants showed decreased contents of chlorophyllide without a substantial change in the total amount of the extractable chlorophyll and consequently presented lower chlorophyllide to chlorophyll ratios in their leaves. In addition, the two AtCLHs exhibited differential expression patterns. Our results suggest that AtCLH2 might play a distinctive role in chlorophyll catabolism in vivo.
Astaxanthin Accumulation in the Green Alga Haematococcus pluvialis: Effects of Cultivation Parameters
Authors: He Ping , Duncan James , Barber James
Published: April 2007

The green alga, Haematococcus pluvialis Flotow is used as a source of the ketocarotenoid astaxanthin for application in fish aquaculture, pharmaceutical and cosmetic industries. Cells of the green alga were induced by the application of different light and starvation conditions to evaluate the effect in astaxanthin accumulate. The conditions used for the induction were high light intensity (170 μmol·m‐2·s‐1), iron starvation, sulfur starvation and phosphate starvation. The results show that stresses applied in culture, which interfere with cell division, trigger the accumulation of astaxanthin. Notably, sulfur starvation results in a massive accumulation of this commercially important carotenoid.
Proteomics Associated with Virulence Differentiation of Curvularia lunata in Maize in China
Authors: Xu Shufa , Chen Jie , Liu Lixing , Wang Xiaofei , Huang Xiuli , Zhai Yuhong
Published: April 2007

One‐dimensional electrophoresis (1‐DE) of proteins, two‐dimensional electrophoresis (2‐DE) of proteins and cloning of cDNA sequence were used to study the virulence differentiation of Curvularia lunata (Wakker) Boed. isolated from maize (Zea maydis L.) in China. From 1‐DE gel profiles of proteins, 110 reproducible bands were separated from six isolates of C. lunata CX‐3, SD‐6, C‐152, C107‐1, DD‐60 and W‐18. Sixty‐eight bands (61.82%) were polymorphic, suggesting huge biodiversities among the isolates. All isolates for the experiment were clustered into three groups consisting of different virulent types by coefficient value of 0.605. Group 1, consisting of CX‐3, SD‐6 and C‐152 with high virulence displayed more protein bands than Groups 2 and 3, consisting of C107‐1 and DD‐60 with low virulence. Proteomics approaches based on 2‐DE techniques were applied to identify specific proteins associated with the virulence differentiation in CX‐3 and DD‐60. A total of 423 protein spots were separated. Out of them 75 specific protein spots were displayed in 2‐DE gels. Among them 28 protein spots were unique in CX‐3 and eight in DD‐60, and 39 protein spots were shown on both 2‐DE gels but expressed differently in intensity. Twenty protein spots including three unique protein spots and 17 differentially expressed protein spots (more than two‐fold DD‐60) in CX‐3 were further identified with MALDI‐TOF MS/MS. Results indicated that most of the identified proteins were found to be associated with virulence differentiation, metabolisms, stress response and signal transduction. One of them was identified as Brn1 protein, which had been reported to be related to melanin biosynthesis and the virulence differentiation in fungi. Combined with our previous findings, we assumed that Brn1 protein and its regulating products might be involved in the virulence differentiation of C. lunata. Consequently, we cloned a Brn1 cDNA fragment and aligned it with the fragments in other fungi. Results indicated that the 633‐bp sequence of Brn1 cloned in C. lunata was highly homological with the compared fungi. Further work for the exact gene roles of Brn1 in our case is underway.
The Challenge of Placing Spirituality within Geographies of Development
Authors: Sanderson Eleanor
Published: April 2007

Debate surrounding spirituality has been gaining prominence within development studies. In contrast to the limited consideration previously given to this issue, recent research is articulating the way that practices of spirituality and development inform one another. Geographies of development must therefore also address these concerns. This is particularly important given the relevance of the spatial politics within this debate to aspects of contemporary human geography. I suggest an embodied geographical approach to be an important way of responding to these debates and the way that they intersect each other, as well as an appropriate place for addressing issues of spirituality within development geography. I discuss how an embodied approach might also address some of the underlying and enduring tensions for development theory and practice, which are, namely, the challenge of negotiating predetermined lacks in the context of multiple and complex relationships.
School Geography and the Politics of Culture
Authors: Morgan John
Published: April 2007

Within school geography in England and Wales, there is increasing interest in using insights from the ‘cultural turn’ in human geography. This article explores the implications of these developments. It discusses how debates about culture influenced educational developments in the 1960s and 1970s and how these stressed that culture and politics are closely linked. The article examines examples of recent materials produced for school geography teachers that draw upon work in cultural geography and argues that these tend to downplay and minimise questions of politics. The article stresses the importance of asking critical questions about the forms of geographical knowledge produced in educational settings.
Dependence of the existence of thermal equilibrium on the number of particles at low temperatures
Authors: Wang X. , Liu Q. H. , Dong W.
Published: April 2007

A universal criterion for the existence of an equilibrium state at low temperatures is established based on the requirement that the temperature fluctuations be small and the third law of thermodynamics. The criterion implies that at sufficiently low temperatures the minimum number of particles increases as the temperature decreases. The application of the criterion to the phonon gas, ideal Bose gas, and the ideal Fermi gas gives quantitative results that are compatible with recent results for nanoscale systems.
Introduction to the quartz tuning fork
Authors: Friedt J.-M. , Carry É.
Published: April 2007

We discuss various aspects of the quartz tuning fork, ranging from its original purpose as a high quality factor resonator for use as a stable frequency reference, to more exotic applications in sensing and scanning probe microscopy. We show experimentally how to tune the quality factor by injecting energy in phase with the current at resonance (quality factor increase) or out of phase (quality factor decrease), hence tuning the sensitivity and the response time of the probe to external disturbances. The principle of shear force scanning probe microscopy is demonstrated on a simple profiler constructed with equipment available in a teaching laboratory.
Gyroscope precession in special and general relativity from basic principles
Authors: Jonsson Rickard M.
Published: April 2007

In special relativity a gyroscope that is suspended in a torque-free manner will precess as it is moved along a curved path relative to an inertial frame S. We explain this effect, which is known as Thomas precession, by considering a real grid that moves along with the gyroscope, and that by definition is not rotating as observed from its own momentary inertial rest frame. From the basic properties of the Lorentz transformation we deduce how the form and rotation of the grid (and hence the gyroscope) will evolve relative to S. As an intermediate step we consider how the grid would appear if it were not length contracted along the direction of motion. We show that the uncontracted grid obeys a simple law of rotation. This law simplifies the analysis of spin precession compared to more traditional approaches based on Fermi transport. We also consider gyroscope precession relative to an accelerated reference frame and show that there are extra precession effects that can be explained in a way analogous to the Thomas precession. Although fully relativistically correct, the entire analysis is carried out using three-vectors. By using the equivalence principle the formalism can also be applied to static spacetimes in general relativity. As an example, we calculate the precession of a gyroscope orbiting a static black hole.
Flexible Faraday Cage with a Twist: Surface Charge on a Möbius Strip
Authors: Stewart Seán
Published: April 2007

Once an intriguing topological novelty known only to mathematicians, the Möbius strip has become a source of fascination and inspiration to the layperson and artist alike.1 Principal among its features are the two strange properties that the Möbius strip is a surface with only one side and one edge. A Möbius strip is readily formed by taking a long rectangular strip of paper and giving one of its ends a half twist before joining it to its other end (see Fig. 1). Given its simplicity, I hoped to profit from its appealing yet counterintuitive nature by designing a simple demonstration experiment that would reveal the intrinsic physical difference between one- and two-sided surfaces.
An Eight-Parameter Function for Simulating Model Rocket Engine Thrust Curves
Authors: Dooling Thomas A.
Published: April 2007

The toy model rocket is used extensively as an example of a realistic physical system. Teachers from grade school to the university level use them. Many teachers and students write computer programs to investigate rocket physics since the problem involves nonlinear functions related to air resistance and mass loss. This paper describes a nonlinear eight-parameter function that correctly models the thrust profile for model rocket engines. Examples are given for commonly used Estes rocket engines.
Debouncing a Superball
Authors: MacInnes Iain
Published: April 2007

Superballs can be purchased in local toy stores. They are described as being highly elastic. For bounces on a wooden bench top, the coefficient of restitution, defined as the ratio of the velocity after collision to the velocity before collision, can be determined from the heights reached on successive rebounds. The value obtained is typically about e = 0.8.
An Inexpensive Apparatus for Demonstrating Magnetic Levitation
Authors: Saraiva Carlos
Published: April 2007

One way of simulating magnetic levitation is by placing a rotating aluminum disk under a magnet.1 In this article, I will explain how to make an inexpensive apparatus to verify this effect, by recycling an obsolete computer.
Clinical Response and Tolerability to and Safety of Saquinavir with Low-Dose Ritonavir in Human Immunodeficiency Virus Type 1-Infected Mothers and Their Infants
Authors: Zorrilla Carmen D. , Van Dyke Russell , Bardeguez Arlene , Acosta Edward P. , Smith Betsy , Hughes Michael D. , Huang Sharon , Watts D. Heather , Heckman Barbara , Jiménez Eleanor , McSherry George , Mofenson Lynne
Published: April 2007

Saquinavir boosted with low-dose ritonavir given with zidovudine and lamivudine was well tolerated by pregnant women and their infants. All mothers had <400 human immunodeficiency virus type 1 RNA copies/ml at delivery. Two had elevated liver transaminases and amylase. Seven infant adverse events were possibly treatment related (anemia, neutropenia, and hyperbilirubinemia).
Identification of the Novel Narrow-Spectrum β-Lactamase SCO-1 in
Acinetobacter
spp. from Argentina
Authors: Poirel Laurent , Corvec Stéphane , Rapoport Melina , Mugnier Pauline , Petroni Alejandro , Pasteran Fernando , Faccone Diego , Galas Marcelo , Drugeon Henri , Cattoir Vincent , Nordmann Patrice
Published: April 2007

By studying the β-lactamase content of several
Acinetobacter
spp. isolates from Argentina, producing the expanded-spectrum β-lactamases (ESBL) VEB-1a or PER-2, a novel Ambler class A β-lactamase gene was identified. It encoded the narrow-spectrum β-lactamase SCO-1, whose activity was inhibited by clavulanic acid. SCO-1 hydrolyzes penicillins at a high level and cephalosporins and carbapenems at a very low level. β-Lactamase SCO-1 was identified from unrelated VEB-1a-positive or PER-2-positive
Acinetobacter
spp. isolates recovered from three hospitals. The
bla
SCO-1
gene was apparently located on a plasmid of ca. 150 kb from all cases but was not associated with any ESBL-encoding gene. The G+C content of the
bla
SCO
gene was 52%, a value that does not correspond to that of the
A. baumannii
genome (39%). β-Lactamase SCO-1 shares 47% amino acid identity with CARB-5 and ca. 40% with the enzymes TEM, SHV, and CTX-M. A gene encoding a putative resolvase was identified downstream of the
bla
SCO-1
gene, but its precise way of acquisition remains to be determined.