bluuebunny/crossref_metadata_2025 huggingface dataset:
Hindfoot Motion following Reconstruction for Posterior Tibial Tendon Dysfunction
Authors: Brodsky James W. , Charlick Daniel A. , Coleman Scott C. , Pollo Fabian E. , Royer Christian T.
Published: July 2009

Introduction:

Due to advances in technology, segmental gait analysis of the foot is now possible and can elucidate hindfoot deformity in persons with posterior tibial tendon dysfunction (PTTD). This study evaluated the motion of the hindfoot and ankle power following surgical reconstruction for PTTD utilizing a segmental foot model during gait.

Materials and Methods:

Twenty patients who underwent posterior tibial tendon reconstruction for Stage 2 PTTD using transfer of the flexor digitorum longus tendon to the navicular tuberosity, reconstruction of the calcaneo-navicular ligament complex, and a medial displacement calcaneal osteotomy were evaluated at a minimum followup of 1 year. Three-dimensional gait analysis was performed utilizing a 4-segment foot model. Temporal-spatial parameters included walking velocity, cadence, step length, and single support time. Sagittal, coronal, and transverse hindfoot motion with respect to the tibia/fibula and ankle power was calculated throughout the gait cycle.

Results:

Walking velocity, cadence, and step length were not significantly different between the study subjects and the normal control group. Study patients did show a significantly smaller single support time on both the affected and unaffected limbs compared to controls. There was no statistical difference in plantarflexion-dorsiflexion, varus-valgus, or ankle push-off power between the affected and unaffected sides of the study subjects, or between the affected side and the controls.

Conclusion:

In this preliminary postoperative study, surgical reconstruction for PTTD effects quantifiable objective improvement in walking velocity, hindfoot motion and power. Level of Evidence: III, Case Control Series
Improvement in Surgical Consent with a Preoperative Multimedia Patient Education Tool: A Pilot Study
Authors: Beamond Ben M. , Beischer Andrew D. , Brodsky James W. , Leslie Hamish
Published: July 2009

Background:

Preoperative education and discussion is a crucial part of the surgeon-patient relationship. The purpose of this study was to assess the efficacy of a multimedia education tool to improve patients' understanding when used as an adjunct to the usual verbal consent process regarding first metatarsophalangeal joint (MTPJ) arthrodesis surgery.

Materials and Methods:

Thirty-one patients were prospectively recruited. There were 24 female and seven male patients with an average age of 56 years. Well-rehearsed, standardized and thorough information regarding the surgery, its risks, benefits, and usual post-operative course were supplied verbally to each patient. Patient understanding was then assessed with a condition specific questionnaire. Following this, each completed a multimedia educational program and repeated the questionnaire, including supplementary questions regarding ease of understanding and satisfaction with the two methods.

Results:

The patients answered 62% questions correctly before the multimedia presentation compared to 87% after it ( p < 0.001). Patients rated the ease of understanding of the multimedia module as a median 9.3 cm along a 10-cm visual analogue scale and 9.1 cm when asked whether it contained the appropriate amount of information to make a decision about surgery. Ninety percent of patients considered that the multimedia tool answered their questions about surgery as well or better than the treating surgeon.

Conclusion:

This study demonstrated that incorporation of a computer-based, multimedia education tool into to the surgical consent process improved patient understanding of the risks, benefits and usual postoperative course following first MTPJ arthrodesis surgery Level of Evidence: II, Prospective Cohort Study
Evaluation of the Hallux Morbidity of Single-Incision Flexor Hallucis Longus Tendon Transfer
Authors: Richardson David R. , Willers Jeffrey , Cohen Bruce E. , Davis W. Hodges , Jones Carroll P. , Anderson Robert B.
Published: July 2009

Background:

Achilles tendinosis and chronic Achilles tendon ruptures are relatively frequently encountered by orthopaedic surgeons. One treatment for patients who fail to respond to conservative management involves augmentation of the repair with transfer of the flexor hallucis longus (FHL), using either a single-incision or double-incision technique. Despite the frequency of this procedure, little is known about the associated donor morbidity. We report the effects of the single-incision technique on hallux function.

Materials and Methods:

We retrospectively reviewed 48 patients who underwent a single-incision FHL tendon transfer for chronic Achilles tendon rupture or Achilles tendinosis. Twenty-two patients (mean followup, 28 months) completed the study. The average age was 56 years. Outcome measures included the American Orthopaedic Foot and Ankle Society (AOFAS) hallux metatarsophalangeal (MTP) joint and interphalangeal (IP) joint scores, the Health Related Quality of Life Measures Short Form (SF-36). Also, the average of two pedobarographic measurements of both feet and strength testing of the FHL of both feet were recorded.

Results:

Decreased distal phalangeal pressure and FHL weakness were demonstrated ( p < 0.05). No difference was noted in plantar pressure of the first or second metatarsal head. The high score on the AOFAS hallux MTP-IP scale demonstrated improved patient forefoot function after FHL transfer through a single-incision technique.

Conclusion:

Flexor hallucis longus tendon transfer using a single-incision technique results in decreased flexion power at the IP joint as demonstrated by decreased distal phalangeal pulp pressure; however, this appears to be a laboratory finding as patient function remains high. Level of Evidence: IV, Retrospective Case Series
Anterior Double Plating for Rigid Fixation of Isolated Tibiotalar Arthrodesis
Authors: Plaass Christian , Knupp Markus , Barg Alexej , Hintermann Beat
Published: July 2009

Background:

Arthrodesis is the most common procedure used to treat end-stage osteoarthritis of the ankle, particularly in patients with difficult conditions such as poor bone quality. While many techniques are available to fuse the ankle, current recommendations favor the use of internal fixation with screws and/or plates. Despite of progress, the complication rate remains a major concern. Non-union is one difficult problem especially with difficult bone conditions, particularly the loss of bone stock on the talar side. Therefore, fusion of the tibiotalar joint is often extended to the talocalcaneal joint to provide sufficient stability. To preserve the subtalar joint, an anterior double plate system for rigid fixation of isolated tibiotalar arthrodesis was developed. This is a preliminary report on the clinical and radiological outcome with this technique.

Materials and Methods:

Twenty-nine patients (15 men, 14 women; one ankle per patient) were treated from October 2006 to September 2007. We converted 16 ankles with osteoarthritis and difficult bone conditions, four non-united ankle arthrodeses, and nine failed total ankle replacements to an isolated tibiotalar arthrodesis using anterior double plating. If necessary, we used solid allograft to fill bony defects. Outcomes included bone union as assessed by radiographs, pain as indicated by the American Orthopaedic Foot and Ankle Society scores, and patient satisfaction.

Results:

Solid arthrodesis was achieved after an average of 12.3 (eight to 26) weeks in the 16 ankles without bone graft interposed between the tibia and talus, and 14.3 (range, 8 to 26) weeks in the 13 ankles with interpositional bone allograft. Radiographs showed that the position of arthrodesis obtained at the time of surgery did not change in any patient up to one year after surgery. The mean American Orthopaedic Foot and Ankle Society (AOFAS) Hindfoot Score increased from 37 (range, 20 to 63) preoperatively to 68 (range, 50 to 92) at the last followup. Twenty-seven patients (93%) were satisfied with their outcome and indicated they would have the operation again. No complications were noted.

Conclusion:

The anterior double plating system was shown be a reliable method to achieve solid isolated tibiotalar arthrodesis, even in ankles with difficult conditions such as loss of bone stock due to failed total ankle arthroplasty. Level of Evidence: IV, Retrospective Case Series
Total Sesamoidectomy for Painful Hallux Rigidus: A Medium-Term Outcome Study
Authors: Tagoe Mark , Brown Henry A. , Rees Sharon M.
Published: July 2009

Background:

The nature of the sesamoid complex in the development of hallux rigidus or limitus (HL) has been poorly characterized and the role of the sesamoids in the surgical management of this condition has not been explored. Previous surgical approaches in younger active patients unsuited to destructive procedures have been limited.

Materials and Methods:

Thirty-three patients (36 procedures) were reviewed between 2 and 4 years following total sesamoidectomy for the management of hallux rigidus/limitus. The American Orthopedic Foot & Ankle Society hallux (AOFAS) clinical rating system was used to compare pre and postoperative scores. The range and quality of motion and transfer metatarsalgia were noted. The three most important patient problems and the degree to which these had been addressed by the surgery and the time to maximal improvement were noted.

Results:

No significant functional impairment or malalignment were found. There were no instances of pain on metatarsal compression, or of transfer metatarsalgia with or without callus formation. A highly statistically significant improvement in AOFAS scores was found ( p < 0.001).

Conclusion:

High levels of clinical improvement and patient satisfaction were found following total sesamoidectomy. No deleterious consequences of sesamoid removal were observed. For symptomatic patients where a joint replacement/fusion is not indicated, total sesamoidectomy was beneficial as an interim procedure, for joints with a moderate (grades 2 to 3) degree of arthrosis. Level of Evidence: IV, Retrospective Case Study
Progressive Neuromuscular Planovalgus Foot Deformity Treated with a Modified Extra-articular Subtalar Fusion
Authors: Vlachou Maria , Dimitriadis Dimitris
Published: July 2009

Background:

Obtaining a successful subtalar fusion in the pediatric population can be challenging. We present our results with a modified extraarticular method.

Materials and Methods:-

We retrospectively evaluated 12 patients (17 feet) with progressive neuromuscular planovalgus foot deformity that underwent an extra-articular subtalar arthrodesis with the combined Batchelor-Grice procedure. All patients were ambulatory and were treated conservatively with braces prior to the operation. The average followup was 10 (range, 5 to 17) years. Postoperatively the feet were immobilized in short leg casts for 6 weeks. Preoperative and postoperative appearance of the feet, the clinical symptoms and radiographic measurements were recorded.

Results:

Sustained correction and solid fusion took place in all feet. Foot appearance and gait pattern of the patients were improved, while preoperative complaints were reduced. Radiographic healing was noted in all cases.

Conclusion:

This technique is an effective treatment for the correction of the deformity as it gives a greater assurance of solidarity than when either of the two procedures is used alone. Level of Evidence: IV, Retrospective Case Series
Results of Metallic Hemi-Great Toe Implant for Grade III and Early Grade IV Hallux Rigidus
Authors: Konkel Kurt F. , Menger Andrea G. , Retzlaff Sharon A.
Published: July 2009

Introduction:

The authors the short-term and mid-term results of patients with their preoperative status who were surgically treated for advanced Grade III and early Grade IV symptomatic hallux rigidus using the Futura Hemi-Great Toe Implant.

Materials and Methods:

The authors were able to contact 23 of 33 consecutive patients. They had a detailed evaluation preoperatively and came in for a detailed mid-term evaluation. Some of the patients were able to come in routinely for detailed periodic evaluations.

Results:

Periodic evaluations showed most patients had a gradual improvement of function over the first 2 years. Patients with early Grade IV disease had a greater propensity to develop early recurrence of their dorsal osteophyte at or before their mid-term followup (average 6 years). In this group of patients, the Futura Hemi-Great Toe Implants lead to 88% good to excellent mid-term results and 88% patient satisfaction over a 6-year average followup.

Conclusion:

Patients with early Grade IV hallux rigidus tend to develop progressive sesamoid arthritis and recurrent dorsal osteophyte formation more rapidly than advanced Grade III patients. Level of Evidence: IV, Retrospective Case Series
Glucocorticoid Injections in Lesions of the Achilles Tendon
Authors: Metcalfe David , Achten Juul , Costa Matthew L.
Published: July 2009

Background:

A number of non-operative interventions are used to manage Achilles tendinopathy. In particular, local glucocorticoid injections have generated controversy. Although a number of case reports indicate symptomatic relief following glucocorticoid injection, one systematic review found little evidence to support their efficacy. Furthermore, local glucocorticoid injections may be associated with rupture of the Achilles tendon. This systematic review considered all available clinical trials measuring the effect of local glucocorticoid injections on symptom relief in patients with Achilles tendinopathy.

Materials and Methods:

The search strategy encompassed five databases: Medline, EMBASE, CINAHL, AMED and the Cochrane Library. Only studies reporting the outcome of glucocorticoid injection for Achilles tendinopathy were included.

Results:

A total of 72 articles were identified, five of which met the inclusion criteria. These included one randomized controlled trial, three retrospective studies, and one prospective case series.

Conclusion:

There is no consensus as to whether local glucocorticoid injections have a therapeutic role in the treatment of Achilles tendinopathy However, they may incur a risk of tendon damage and therefore further research is required before glucocorticoid injections can be recommended for use in Achilles tendinopathy. Level of Evidence: III, Systematic Review of Level I-IV Studies
Early Mobilization of Operatively Fixed Ankle Fractures: A Systematic Review
Authors: Thomas Gethin , Whalley Helen , Modi Chetan
Published: July 2009

Background:

It is commonly believed that early motion after joint fixation is advantageous, especially in the upper limb. In the ankle joint this is much less clear. No previous systematic review of the evidence for this could be found in the literature.

Materials and Methods:

Nine randomized control trials were identified which met the inclusion criteria and compared early motion of the ankle joint to immobilization in a cast for 6 weeks. These varied in quality and numbers. All treated patients equally in all other respects including weight bearing. Where outcome measures were similar, some data pooling was possible.

Results:

There is good evidence that early motion is associated with a quicker return to work on average ( p = 0.008) and also with an improved range of motion at 12 weeks (dorsiflexion p = 0.001; plantarflexion p < 0.00001) compared to cast immobilization. However it is also associated with an increased risk of wound infection ( p = 0.002). There is a suggestion that early motion results in a lower rate of deep vein thrombosis ( p = 0.12). There is no evidence that it results in improved joint specific outcome scores or range of motion at 1 year.

Conclusion:

It is difficult to conclude whether early motion is overall better or worse than cast immobilization. The evidence suggests however that a young fit patient who needs to return to work may benefit from early motion of the ankle joint whereas a patient with poor skin or at risk of infection may be better treated in a cast after surgery. Level of Evidence: I, Systematic Review of Level I-II Studies
Arthroscopic Lateral Release and Percutaneous Distal Osteotomy for Hallux Valgus: A Preliminary Report
Authors: Siclari Alberto , Decantis Vito
Published: July 2009

Distal osteotomy of the first metatarsal is frequently used for the treatment of hallux valgus deformity. The great toe arthroscopy is a safe procedure to perform a distal soft tissue release and a complete evaluation of the first metatarsal-phalangeal joint. The aim of this study was to evaluate the results of the arthroscopic distal soft tissue release with a distal percutaneous osteotomy in the treatment of hallux valgus deformity. From January 1, 2003, to August 1, 2006, 59 consecutive procedures were performed in 49 patients. Clinical evaluation was calculated using the hallux score of the American Orthopedic Foot and Ankle Society (AOFAS). The mean follow up was 31.48 (range, 12 to 48) months and the AOFAS score improved from 45 (range, 30 to 65) points to 90.61 (range, 75 to 100). The excellent results obtained encourage the authors to go on treat the hallux valgus deformity with this combination of two minimal invasive procedures.

Level of Evidence: IV, Retrospective Case Series
Minimally Invasive Paratenon Release for Non-Insertional Achilles Tendinopathy
Authors: Naidu Venunatha , Abbassian Ali , Nielsen Dominic , Uppalapati Raju , Shetty Anupkumar
Published: July 2009

Background:

Non-insertional Achilles tendinopathy is an increasing, perhaps secondary to an increase in sporting activities. Traditional open surgical procedures have been associated with a significant rate of complications. We describe a minimally invasive technique involving the release of the adherent paratenon with a peritendinous infusion of corticosteroids and present the results in a cohort of patients.

Materials and Methods:

Twenty-nine tendons (26 patients) with non-insertional Achilles tendinopathy were treated with the above technique. Assessments were made prospectively using an adapted classification of Achilles tendon disability and a visual analogue scale for pain. Patients were interviewed in person or by telephone at an average of 14 (range, 6 to 30) months after surgery.

Results:

The average pain score (VAS) improved from 8.7 to 2.4 ( p < 0.001) and the average Puddu level of disability improved from 4.9 to 1.7 ( p < 0.001). Seventy-five percent of patients had a good or excellent outcome with 20% having sufficient improvement not to pursue further medical attention for their tendinopathy. There was a 7% rate of minor complications due to delayed wound healing which resolved spontaneously and did not affect the rehabilitation or the recovery of the patients.

Conclusion:

A minimally invasive circumferential paratenon release and peritendinous steroid infusion was a simple method to treat non-insertional Achilles tendinopathy and had low morbidity in our series. This technique has become our preferred primary surgical intervention for this condition. Level of Evidence: IV, Retrospective Case Series
Locally Generated Bone Slurry Accelerated Ankle Arthrodesis
Authors: Wheeler Jacynda , Sangeorzan Adam , Crass Sarah M. , Sangeorzan Bruce J. , Benirschke Stephen K. , Hansen Sigvard T.
Published: July 2009

Background:

Reported ankle fusion healing times vary between 7 to 72 weeks. High non-union and delayed union rates have led to an increased use of bone graft and bone graft substitutes. It was our goal to see if addition of a bone slurry could accelerate the rate of healing.

Materials and Methods:

We compared the radiographic healing after ankle arthrodesis in two groups of patients treated over 3 years with and without a ‘bone slurry.’ In group one, a slurry of bone particles was generated with a low-speed burr and left in the joint before internal fixation. Group two had similar fixation but no bone slurry. Two reviewers, blinded to the presence or absence of slurry, studied magnified digital radiographs at 6 and 12 weeks. The percentage of the joint bridged by bone was recorded for each and the groups were averaged. Groups were compared using Wilcoxon rank sum.

Results:

There were 32 patients in group one and 22 in group two. Groups were similar in age, gender and diagnosis. At 6 weeks, group one had 94.1% bridging bone, as measured on AP radiographs. Group two had 76.4% bridging bone. (Wilcoxon rank sum test p = 0.0099). At 12 weeks, group one had 98.1% bridging bone and group two had 85.7% bridging bone (Wilcoxon rank sum test p = 0.026).

Conclusion:

Use of a low-speed burr to generate a “bone paste” from the local bone surfaces was associated with an increased percentage of healed bone surface at 6 and 12 weeks in patients undergoing ankle arthrodesis. Level of Evidence: III, Retrospective Case Control
Accuracy of Anterolateral Drawer Test in Lateral Ankle Instability: A Cadaveric Study
Authors: Phisitkul Phinit , Chaichankul Chaisiri , Sripongsai Ratthapol , Prasitdamrong Ittipol , Tengtrakulcharoen Pannipa , Suarchawaratana Siripim
Published: July 2009

Background:

In the assessment of lateral ankle instability, the anterior drawer test has been found to be inaccurate and the focus on pure anterior translation cannot properly perceive the anterolateral rotatory nature of the talar displacement. In order to address this, the anterolateral drawer test can be done with digital palpation of the talar displacement anterolaterally with a controlled angle of plantarflexion as well as application of the translational force.

Materials and Methods:

We evaluated the anterolateral drawer test and the original anterior drawer test in 10 fresh below-the-knee specimens using a direct anatomic measurement (DAM) loaded by a Telos stress device as a reference. Specimens were assigned into three groups: intact ligaments, ATFL-cut, and ATFL&CFL-cut. The examiners were blinded with one performing the anterolateral drawer test (E1) while the other performed the original anterior drawer test (E2).

Results:

Pearson's correlation coefficient indicated a statistically significant linear relationship between DAM/E1 r = 0.931, p < 0.001 but not between DAM/E2 r = 0.519, p = 0.124. Intraclass correlation coefficient show correlation between DAM/E1 and DAM/E2 to be 0.945 ( p < 0.001) and 0.683 ( p = 0.051). When 3 mm or more was used as the threshold to diagnose a lateral ligament rupture, sensitivity and specificity were E1(100%, 100%) and E2(75%, 50%).

Conclusion:

The anterolateral drawer test showed high accuracy in the determination of lateral ankle instability and in the diagnosis of a ligament rupture.

Clinical Relevance:

Further investigation regarding the accuracy and reliability of this test in comparison with the original anterior drawer test is warranted in a patient population with ankle instability.
Comparison of Augmentation Methods for Internal Fixation of Osteoporotic Ankle Fractures
Authors: Panchbhavi Vinod K. , Vallurupalli Santaram , Morris Randal
Published: July 2009

Background:

Internal fixation of osteoporotic ankle fractures is associated with failure of fixation. This study compared different augmentation methods biomechanically.

Materials and Methods:

In nine paired fresh-frozen cadaver legs, an identical supination-external rotation type II ankle fracture was created. Fractures were stabilized using an eight-hole locking plate. In four pairs, two screws were inserted across the syndesmosis for purchase in the tibial metaphysis. One leg from each pair was randomly selected for injection of calcium sulphate-calcium phosphate graft into the screw holes. Each leg was mounted to an MTS machine in a custom loading frame. Axial cyclic loading to body weight was performed to measure displacement at the fracture site, followed by rotational loading to failure simulating a supination external rotation injury. Data were analyzed using a two-way paired t -test and ANOVA.

Results:

The specimens used had a mean bone mineral density of 0.49 ± 0.15 (SD) g/cm2, and a mean age of 83 ± 12 years. In the biomechanical tests, there were no significant differences between augmented and non-augmented locking plates without the tibia-pro-fibula screws in axial stiffness ( p = 0.10), external rotation angle at failure ( p = 0.42), failure torque ( p = 0.57), energy absorbed before failure ( p = 0.47), and motion at the fracture site with cyclic axial loading ( p = 0.15). There were no significant differences between augmented and non-augmented locking plates with the tibia-pro-fibula screws in the external rotation angle at failure ( p = 0.83), failure torque ( p = 0.58), and failure energy ( p = 0.4). However, the overall strength of the fixation tended to increase with tibia-pro-fibula screws and augmentation.

Conclusion:

Internal fixation of an osteoporotic lateral malleolar fracture using a locking plate and screws provided a construct comparable in strength to that augmented with calcium sulfate-calcium phosphate graft and/or tibia-pro-fibula screws.

Clinical Relevance:

Strategies to augment internal fixation of osteoporotic ankle fractures may minimize risk for failure of fixation and may enable early weight bearing mobilization and return to function in elderly patients.
Technique Tip: The Use of a Washer and Suture Endobutton in Revision Lisfranc Fixation
Authors: Lundeen Gregory , Sara Steven
Published: July 2009

Level of Evidence: V, Expert Opinion
Toward a New Process-Based Indicator for Measuring Writing Fluency: Evidence from L2 Writers' Think-Aloud Protocols
Authors: Abdel Latif Muhammad M.
Published: July 2009

This article reports on a study aimed at testing the hypothesis that, because of strategic and temporal variables, composing rate and text quantity may not be valid measures of writing fluency. A second objective was to validate the mean length of writers' translating episodes as a process-based indicator that mirrors their fluent written production rather than the factors that may be related to it. The translating episode is defined as any chunk that has been written down and terminated by a pause of three or more seconds or by any composing behaviour. Data for the study were drawn from the think-aloud protocols generated by 30 Egyptian university students writing in their second language (L2) and from their retrospective interviews. To examine the validity of the three indicators, the participants' composing rates, text quantity, and translating episodes were related to their scores on an argumentative writing task and on three linguistic tests. The results of the quantitative and qualitative analyses confirm the hypothesis tested and provide evidence for the validity of this newly developed indicator of writing fluency. Implications and suggestions for further research are presented.
Negotiating Curricular Transitions: Foreign Language Teachers' Learning Experience with Content-Based Instruction
Authors: Cammarata Laurent
Published: July 2009

Content-based instruction (CBI) has been touted as an effective curricular approach in a wide range of educational contexts, including immersion and English as a second language. Yet this approach to curriculum design is rarely implemented in conventional K–16 foreign language (FL) programs in the United States today. The phenomenological study described here attempted to gain a deeper understanding of factors affecting the implementation of CBI by exploring three traditional FL teachers' learning experiences during a year-long professional-development program designed to introduce the approach. Transitioning toward CBI, the findings suggest, can be a professionally intimidating experience, involving a struggle to re-examine one's own teaching identity and one's vision of what teaching and learning ought to be. Important implications emerging from this study include a need for professional-development programs to better scaffold teachers' learning experience and to create safer environments for teachers to explore pedagogical alternatives.
L'aspect lexical et le développement du passé composé et de l'imparfait en français L2 : Une étude quantitative auprès d'apprenants hispanophones
Authors: Izquierdo Jesús
Published: July 2009

Lexical aspect and L1-L2 differences are often associated with the perfective and prototypical preference that characterises the development of the L2 French past tense among Anglophones. This study examined whether learners of French with the imperfective in their L1 would exhibit this developmental L2 past tense preference. The overall and appropriate uses of the French perfective and imperfective of 44 Hispanophones from four L2 tense-aspect proficiency levels were documented through a cloze task with 23 prototypical and 23 non-prototypical contexts. ANOVAs of the 2254 tokens generated by the participants revealed that, at low L2 proficiency levels, the participants overrode the perfective preference. Prototypical marking remained a preference across L2 proficiency levels, however. This finding reveals that lexical aspect constitutes a shared L2 acquisition challenge for the use of temporal morphology in L2 non-prototypical contexts even among learners who override verb semantics in their L1.
Le cadeau or la cadeau? The Role of Aptitude in Learner Awareness of Gender Distinctions in French
Authors: Bell Philippa
Published: July 2009

Research has shown differences among learners in terms of their level of awareness of grammatical features in the input. Reasons for these differences have not been widely researched, despite the pedagogical importance of understanding what different learners are noticing. It has been found, however, that learners' grammatical sensitivity and memory may play a role. The present study investigated whether awareness can be predicted by five individual difference measures: attention control, working memory, phonologic memory, grammatical sensitivity, and inductive language learning ability. Forty-six anglophone adults with pre-intermediate French completed a crossword task that provided exposure to two reliable noun endings for attributing gender (cadeau/rondelle). A think-aloud protocol and two probe questions measured awareness. Participants were divided into two groups: aware and no verbal report. A regression analysis showed that only the test of inductive language learning ability could predict assignment to awareness group. Implications for aptitude, awareness, and L2 proficiency research are discussed.
Wood anatomy and wood density in shrubs: Responses to varying aridity along transcontinental transects
Authors: Martínez‐Cabrera Hugo I. , Jones Cynthia S. , Espino Susana , Schenk H. Jochen
Published: July 2009

Wood density plays a key role in ecological strategies and life history variation in woody plants, but little is known about its anatomical basis in shrubs. We quantified the relationships between wood density, anatomy, and climate in 61 shrub species from eight field sites along latitudinal belts between 31° and 35° in North and South America. Measurements included cell dimensions, transverse areas of each xylem cell type and percentage contact between different cell types and vessels. Wood density was more significantly correlated with precipitation and aridity than with temperature. High wood density was achieved through reductions in cell size and increases in the proportion of wall relative to lumen. Wood density was independent of vessel traits, suggesting that this trait does not impose conduction limitations in shrubs. The proportion of fibers in direct contact with vessels decreased with and was independent of wood density, indicating that the number of fiber‐vessel contacts does not explain the previously observed correlation between wood density and implosion resistance. Axial and radial parenchyma each had a significant but opposite association with wood density. Fiber size and wall thickness link wood density, life history, and ecological strategies by controlling the proportion of carbon invested per unit stem volume.
Do lichens domesticate photobionts like farmers domesticate crops? Evidence from a previously unrecognized lineage of filamentous cyanobacteria
Authors: Lücking Robert , Lawrey James D. , Sikaroodi Masoumeh , Gillevet Patrick M. , Chaves José Luis , Sipman Harrie J. M. , Bungartz Frank
Published: July 2009

Phylogenetic diversity of lichen photobionts is low compared to that of fungal counterparts. Most lichen fungi are thought to be associated with just four photobiont genera, among them the cyanobacteria Nostoc and Scytonema, two of the most important nitrogen fixers in humid ecosystems. Although many Nostoc photobionts have been identified using isolated cultures and sequences, the identity of Scytonema photobionts has never been confirmed by culturing or sequencing. We investigated the phylogenetic placement of presumed Scytonema photobionts and unicellular morphotypes previously assigned to Chroococcus, from tropical Dictyonema, Acantholichen, Coccocarpia, and Stereocaulon lichens. While we confirm that filamentous and unicellular photobiont morphotypes belong to a single clade, this clade does not cluster with Scytonema but represents a novel, previously unrecognized, highly diverse, exclusively lichenized lineage, for which the name Rhizonema is available. The phylogenetic structure observed in this novel lineage suggests absence of coevolution with associated mycobionts at the species or clade level. Instead, highly efficient photobiont strains appear to have evolved through photobiont sharing between unrelated, but ecologically similar, coexisting lineages of lichenized fungi (“lichen guilds”), via the selection of particular photobiont strains through and subsequent horizontal transfer among unrelated mycobionts, a phenomenon not unlike crop domestication.
Water stress tolerance of shrubs in Mediterranean‐type climate regions: Convergence of fynbos and succulent karoo communities with California shrub communities
Authors: Jacobsen Anna L. , Esler Karen J. , Pratt R. Brandon , Ewers Frank W.
Published: July 2009

Mediterranean‐type climate regions are highly biodiverse and predicted to be particularly sensitive to climate change. Shrubs of the mediterranean‐type climate region of South Africa are highly threatened, and their response to water stress has been comparatively little studied. Resistance to water stress induced xylem cavitation (P50) and xylem specific hydraulic conductivity (Ks) were measured in 15 shrub species from fynbos and succulent karoo communities of South Africa. Species displayed a fivefold variation in cavitation resistance (P50 of −1.9 to −10.3 MPa) with succulent karoo species displaying greater interspecific variability in P50 than fynbos species. Principal components analysis (including P50, minimum seasonal water potential, Ks, and xylem density) showed the response to water stress in fynbos species to be similar to chaparral species from the mediterranean‐type climate region of California. The data suggest convergence of community and species‐specific water stress “strategies” between these mediterranean‐type climate regions with respect to their xylem traits. On the basis of the current study and reported plant death and dieback in these regions, woody species within the fynbos may be more susceptible to climate warming and drying than those within the succulent karoo that appear to be utilizing more diverse xylem strategies in response to water stress.
MADS‐box gene expression and implications for developmental origins of the grass spikelet
Authors: Preston Jill C. , Christensen Ashley , Malcomber Simon T. , Kellogg Elizabeth A.
Published: July 2009

Basic questions regarding the origin and evolution of grass (Poaceae) inflorescence morphology remain unresolved, including the developmental genetic basis for evolution of the highly derived outer spikelet organs. To evaluate homologies between the outer sterile organs of grass spikelets and inflorescence structures of nongrass monocot flowers, we describe expression patterns of APETALA1/FRUITFULL‐like (AP1/FUL) and LEAFY HULL STERILE‐like (LHS1) MADS‐box genes in an early‐diverging grass (Streptochaeta angustifolia) and a nongrass outgroup (Joinvillea ascendens). AP1/FUL‐like genes are expressed only in floral organs of J. ascendens, supporting the hypothesis that they mark the floral boundary in nongrass monocots, and JaLHS1/OsMADS5 is expressed in the inner and outer tepals, stamen filaments and pistil. In S. angustifolia, SaFUL2 is expressed in all 11 (or 12) bracts of the primary inflorescence branch, but not in the suppressed floral bract below the abscission zone. In contrast, SaLHS1 is only expressed in bracts 6–11 (or 12). Together, these data are consistent with the hypotheses that (1) bracts 1–5 of S. angustifolia primary inflorescence branches and glumes of grass spikelets are homologous and that (2) the outer tepals of immediate grass relatives, bracts 6–8 of S. angustifolia, and the lemma/palea are homologous, although other explanations are possible.
Deletion of the C-Terminal Region of Dengue Virus Nonstructural Protein 1 (NS1) Abolishes Anti-NS1-Mediated Platelet Dysfunction and Bleeding Tendency
Authors: Chen Mei-Chun , Lin Chiou-Feng , Lei Huan-Yao , Lin Shih-Chao , Liu Hsiao-Sheng , Yeh Trai-Ming , Anderson Robert , Lin Yee-Shin
Published: July 2009

The mechanisms underlying dengue hemorrhagic disease are incompletely understood. We previously showed that anti-dengue virus (DV) nonstructural protein 1 (NS1) Abs cross-react with human platelets and inhibit platelet aggregation. Based on sequence homology alignment, the cross-reactive epitopes reside in the C-terminal region of DV NS1. In this study, we compared the effects of Abs against full-length DV NS1 and NS1 lacking the C-terminal aa 271 to 352 (designated ΔC NS1). Anti-ΔC NS1 Abs exhibited lower platelet binding activity than that of anti-full-length NS1. Anti-full-length NS1 but not anti-ΔC NS1 Abs inhibited platelet aggregation, which was shown to involve integrin αIIbβ3 inactivation. We found that the bleeding time in full-length NS1-hyperimmunized mice was longer than that in the normal control mice. By contrast, ΔC NS1-hyperimmunized mice showed a bleeding time similar to that of normal control mice. Passively administered anti-DV NS1, but not anti-ΔC NS1, Ab level decreased markedly in serum and this decrease was correlated with Ab binding to platelets. A transient platelet loss in the circulation was observed after anti-DV NS1, but not anti-ΔC NS1, Ab administration. In summary, platelet dysfunction and bleeding tendency are induced by anti-full-length DV NS1 but not by anti-ΔC NS1 Abs. These findings may be important not only for understanding dengue hemorrhagic disease pathogenesis but also for dengue vaccine development.
Recurrence of Intracranial Tumors following Adoptive T Cell Therapy Can Be Prevented by Direct and Indirect Killing Aided by High Levels of Tumor Antigen Cross-Presented on Stromal Cells
Authors: Thomas Diana L. , Kim Miri , Bowerman Natalie A. , Narayanan Samanthi , Kranz David M. , Schreiber Hans , Roy Edward J.
Published: July 2009

Elimination of peripheral tumors by adoptively transferred tumor-specific T cells may require killing of cancer cells and tumor stromal cells. Tumor Ags are cross-presented on stromal cells, resulting in direct cytotoxic T cell (CTL) killing of both Ag-expressing cancer cells and stromal cells. Indirect killing of Ag loss variant cells also occurs. We show here that similar processes occur in a brain tumor stromal environment. We used murine cancer cell lines that express high or low levels of a peptide Ag, SIYRYYGL (SIY), recognized by transgenic 2C CD8+ T cells. The two cell lines are killed with equivalent efficiency by 2C T cells in vitro. Following adoptive transfer of 2C T cells into mice with established SIY-Hi or SIY-Lo brain tumors, tumors of both types regressed, but low-Ag-expressing tumors recurred. High-Ag-expressing tumors contained CD11b+ cells cross-presenting SIY peptide and were completely eliminated by 2C T cells. To further test the role of cross-presentation, RAG1−/− H-2b mice were infused with H-2k tumor cells expressing high levels of SIY peptide. Adoptively transferred 2C T cells are able to kill cross-presenting H-2b stromal cells but not H-2k tumor cells. In peripheral models, this paradigm led to a small static tumor. In the brain, activated 2C T cells were able to kill cross-presenting CD11b+ cells and completely eliminate the H-2k tumors in most mice. Targeting brain tumor stroma or increasing Ag shedding from tumor cells to enhance cross-presentation may improve the clinical success of T cell adoptive therapies.
Diminished Intracellular Invariant Chain Expression after Vaccinia Virus Infection
Authors: Wang Nan , Weber Ekkehard , Blum Janice S.
Published: July 2009

Vaccinia virus (VV) has been used as a vaccine to eradicate smallpox and as a vaccine for HIV and tumors. However, the immunoevasive properties of VV have raised safety concerns. VV infection of APCs perturbs MHC class II-mediated Ag presentation. Exposure of human B cell lines to VV induced a substantial reduction in cellular expression of the class II chaperone, invariant chain (Ii), during the late stages (i.e., 8–10 h) of infection. Yet, cell viability and surface expression of MHC class II molecules were maintained up to 24 h after exposure to virus. Reductions in Ii and class II mRNA levels were detected as early as 6 h after VV infection of APCs. To examine whether VV was acting solely to disrupt host protein synthesis, B cells were treated with an inhibitor of translation, cycloheximide (CHX). Within 1 h of B cell CHX treatment, Ii protein expression decreased coupled with a loss of class II presentation. Analysis of Ii degradation in VV- or CHX-treated cells, revealed ongoing Ii proteolysis contributing to reduced steady-state Ii levels in these APC. Yet in contrast with CHX, VV infection of APCs altered lysosomal protease expression and Ii degradation. Virus infection induced cellular cathepsin L expression while reducing the levels of other lysosomal proteases. These results demonstrate that at late stages of VV infection, reductions in cellular Ii levels coupled with changes in lysosomal protease activity, contribute in part to defects in class II presentation.
IL-6 Is Required for Airway Mucus Production Induced by Inhaled Fungal Allergens
Authors: Neveu Wendy A. , Allard Jenna B. , Dienz Oliver , Wargo Matthew J. , Ciliberto Gennaro , Whittaker Laurie A. , Rincon Mercedes
Published: July 2009

Allergic asthma is caused by inhaled allergens and is characterized by airway eosinophilia, as well as mucus hypersecretion, which can lead to airflow obstruction. Despite the association of increased IL-6 levels with human atopic asthma, the contribution of IL-6 to the development of allergic airway inflammation triggered by inhaled allergens remains unclear. In this study, we examined the role of IL-6 in a mouse model of allergic airway inflammation induced by direct airway exposure to extracts of Aspergillus fumigatus, a common allergen in humans. We show that inhaled A. fumigatus extracts rapidly trigger the production of IL-6 in the airways. IL-6 appears to be dispensable for the recruitment of eosinophils to the lung during the development of allergic airway inflammation. However, IL-6 is essential for mucus hypersecretion by airway epithelial cells triggered in response to inhaled A. fumigatus Ags. Impaired mucus production caused by IL-6 deficiency correlates with a severe reduction in the levels of IL-13, a major inducer of mucin glycoproteins. Thus, IL-6 is a key regulator of specific hallmark features of allergic airway inflammation and it could be a potential target for pulmonary diseases that are associated with goblet cell metaplasia and mucus hypersecretion.
An Atopy-Associated Polymorphism in the Ectodomain of the IL-4Rα Chain (V50) Regulates the Persistence of STAT6 Phosphorylation
Authors: Ford Andrew Q. , Heller Nicola M. , Stephenson Linda , Boothby Mark R. , Keegan Achsah D.
Published: July 2009

Several commonly occurring polymorphisms in the IL-4Rα have been associated with atopy in humans; the Q576R and the S503P polymorphisms reside in the cytoplasmic domain, whereas the I50 to V50 polymorphism resides in the extracellular domain of the IL-4Rα. The effects of these polymorphisms on signaling remain controversial. To determine the effect of the polymorphisms on IL-4 signaling in human cells, we stably transfected the human monocytic cell line U937 with murine IL-4Rα cDNA bearing the I or V at position 50 and the P503/R576 double mutant. Each form of the murine IL-4Rα mediated tyrosine phosphorylation of STAT6 in response to murine IL-4 treatment similar to the induction of tyrosine phosphorylation by human IL-4 signaling through the endogenous human IL-4Rα. After IL-4 removal, tyrosine-phosphorylated STAT6 rapidly decayed in cells expressing I50 or P503R576 murine IL-4Rα. In contrast, STAT6 remained significantly phosphorylated for several hours after murine IL-4 withdrawal in cells expressing the V50 polymorphism. This persistence in tyrosine-phosphorylated STAT6 was associated with persistence in CIS mRNA expression. Blocking IL-4 signaling during the decay phase using the JAK inhibitor AG490 or the anti-IL-4Rα Ab M1 abrogated the persistence of phosphorylated STAT6 observed in the V50-IL-4Rα-expressing cells. These results indicate that the V50 polymorphism promotes sustained STAT6 phosphorylation and that this process is mediated by continued engagement of IL-4Rα, suggesting enhanced responses of V50 IL-4R when IL-4 is limiting.
IFN Regulatory Factor 4 Regulates the Expression of a Subset of Th2 Cytokines
Authors: Ahyi Ayele-Nati N. , Chang Hua-Chen , Dent Alexander L. , Nutt Stephen L. , Kaplan Mark H.
Published: July 2009

Th2 cells can be subdivided into subpopulations depending on the level of a cytokine and the subsets of cytokines they produce. We have recently identified the ETS family transcription factor PU.1 as regulating heterogeneity in Th2 populations. To define additional factors that might contribute to Th2 heterogeneity, we examined the PU.1 interacting protein IFN-regulatory factor (IRF)4. When Th2 cells are separated based on levels of IL-10 secretion, IRF4 expression segregates into the subset of Th2 cells expressing high levels of IL-10. Infection of total Th2 cells, and IL-10 nonsecreting cells, with retrovirus-expressing IRF4, resulted in increased IL-4 and IL-10 expression, no change in IL-5 or IL-13 production and decreased Il9 transcription. Transfection of an IRF4-specific small interfering RNA into Th2 cells decreases IL-10 production. IRF4 directly binds the Il10 gene as evidenced by chromatin immunoprecipitation assay, and regulates Il10 control elements in a reporter assay. IRF4 interacts with PU.1, and in PU.1-deficient T cells there was an increase in IRF4 binding to the Il10 gene, and in the ability of IRF4 to induce IL-10 production compared with wild-type cells and Il10 promoter activity in a reporter assay. Further heterogeneity of IRF4 expression was observed in Th2 cells analyzed for expression of multiple Th2 cytokines. Thus, IRF4 promotes the expression of a subset of Th2 cytokines and contributes to Th2 heterogeneity.