bluuebunny/crossref_metadata_2025 huggingface dataset:
On the specification of structural equation models for ecological systems
Authors: Grace James B. , Anderson T. Michael , Olff Han , Scheiner Samuel M.
Published: March 2010

The use of structural equation modeling (SEM) is often motivated by its utility for investigating complex networks of relationships, but also because of its promise as a means of representing theoretical concepts using latent variables. In this paper, we discuss characteristics of ecological theory and some of the challenges for proper specification of theoretical ideas in structural equation models (SE models). In our presentation, we describe some of the requirements for classical latent variable models in which observed variables (indicators) are interpreted as the effects of underlying causes. We also describe alternative model specifications in which indicators are interpreted as having causal influences on the theoretical concepts. We suggest that this latter nonclassical specification (which involves another variable type—the composite) will often be appropriate for ecological studies because of the multifaceted nature of our theoretical concepts.

In this paper, we employ the use of meta‐models to aid the translation of theory into SE models and also to facilitate our ability to relate results back to our theories. We demonstrate our approach by showing how a synthetic theory of grassland biodiversity can be evaluated using SEM and data from a coastal grassland. In this example, the theory focuses on the responses of species richness to abiotic stress and disturbance, both directly and through intervening effects on community biomass. Models examined include both those based on classical forms (where each concept is represented using a single latent variable) and also ones in which the concepts are recognized to be multifaceted and modeled as such. To address the challenge of matching SE models with the conceptual level of our theory, two approaches are illustrated, compositing and aggregation. Both approaches are shown to have merits, with the former being preferable for cases where the multiple facets of a concept have widely differing effects in the system and the latter being preferable where facets act together consistently when influencing other parts of the system. Because ecological theory characteristically deals with concepts that are multifaceted, we expect the methods presented in this paper will be useful for ecologists wishing to use SEM.
DO CHILDREN PREFER CONTINGENCIES? AN EVALUATION OF THE EFFICACY OF AND PREFERENCE FOR CONTINGENT VERSUS NONCONTINGENT SOCIAL REINFORCEMENT DURING PLAY
Authors: Luczynski Kevin C. , Hanley Gregory P.
Published: March 2010

Discovering whether children prefer reinforcement via a contingency or independent of their behavior is important considering the ubiquity of these programmed schedules of reinforcement. The current study evaluated the efficacy of and preference for social interaction within differential reinforcement of alternative behavior (DRA) and noncontingent reinforcement (NCR) schedules with typically developing children. Results showed that 7 of the 8 children preferred the DRA schedule; 1 child was indifferent. We also demonstrated a high degree of procedural fidelity, which suggested that preference is influenced by the presence of a contingency under which reinforcement can be obtained. These findings are discussed in terms of (a) the selection of reinforcement schedules in practice, (b) variables that influence children's preferences for contexts, and (c) the selection of experimental control procedures when evaluating the effects of reinforcement.
MODIFICATION OF PERSEVERATIVE RESPONDING THAT INCREASED EARNINGS BUT IMPEDED SKILL ACQUISITION IN A JOB‐SKILLS TRAINING PROGRAM
Authors: DeFulio Anthony , Iati Carina , Needham Mick , Silverman Kenneth
Published: March 2010

Adults in a therapeutic workplace working on a computerized keyboarding training program earned vouchers for typing correct characters. Typing technique was evaluated on review steps. Participants could pass the review and earn a bonus, or skip the review and proceed with no bonus. Alternatively, participants could continue practicing on the same step. Participants persistently repeated the same step, which halted progress through the program but allowed them to increase their rate of responding and, as a result, their earnings. Blocking the initiation of practice on review steps and removing payment for practice initiated after prompts (extinction) both produced rapid progress through the program. These results underscore the importance of careful arrangement of the contingencies in adult education programs.
Prospective Assessment of the Use of Enamel Matrix Derivative With Minimally Invasive Surgery: 6‐Year Results
Authors: Harrel Stephen K. , Wilson Thomas G. , Nunn Martha E.
Published: March 2010

Background: Minimally invasive surgery (MIS) is a surgical technique using very small incisions indicated for performing regenerative therapy in periodontal defects. The 11‐month results from a prospective study of MIS were previously published. This article presents the 6‐year results of that prospective study.

Methods: Patients from two private periodontal practices with advanced periodontitis who, after non‐surgical therapy, had one or more sites with probing depths ≥6 mm were included in the study. An MIS surgical approach was used for all sites ≥6 mm. After surgical debridement, enamel matrix derivative (EMD) was placed into the bony defect. The surgical sites were reevaluated after ≥6 years.

Results: Six‐year data were available on 142 sites in 13 patients. No significant differences were noted in the results between the two offices, and the data were combined. Probing depths (mean: 3.18 mm; SD: 0.59 mm) and attachment levels (mean: 3.93 mm; SD: 0.19) at 6 years were unchanged from the 11‐month measurements. No recession from preoperative levels was noted. All sites continued to be considered clinically successful.

Conclusions: The combination of MIS and EMD yielded significant reductions in probing depths and improvements in attachment levels while producing no detectable recession. The 11‐month results remained stable at 6 years.
Health Behaviors, Periodontal Conditions, and Periodontal Pathogens in Spontaneous Preterm Birth: A Case‐Control Study in Korea
Authors: Ryu Jae‐In , Oh KyungJoon , Yang HyeJin , Choi Bong‐Kyu , Ha Jung‐Eun , Jin Bo‐Hyoung , Kim Hyun‐Duck , Bae Kwang‐Hak
Published: March 2010

Background:This study aims to determine whether periodontal conditions or dental health behaviors are risk factors for preterm birth (PTB), and whether periodontal pathogens are risk indicators for PTB among Korean mothers.

Methods:This study was designed as a hospital‐based case‐control study. Examiner masking was ensured for the validity of the examinations. The mothers included those who gave birth between November 2007 and July 2009 at the obstetrics clinic of a general hospital in Seoul, Korea. Information on demographic and health conditions, periodontal conditions, and microbacterial data was collected.

Results:A total of 172 women met the inclusion criteria, 59 mothers who delivered a preterm neonate were assigned to the case group while the other 113 were assigned to the control group. There were no significant differences in demographic information, oral health conditions, and obstetric characteristics. Among health‐related behaviors, only scaling within 12 months before pregnancy showed a significant difference (P= 0.031). Even in the adjusted logistic model, only the difference in the experience of scaling before pregnancy was significant between the PTB cases and the controls (P= 0.039). Periodontal disease did not exhibit a significant relationship with PTB even after adjustment for potential confounding factors. Among the microbacterial factors, onlyPorphyromonas gingivalisshowed a slight difference (P= 0.060).

Conclusion:There was a significant difference in scaling experience within 12 months before pregnancy andP. gingivalisshowed a marginal difference between the PTB and the control groups but clinical periodontal conditions showed no association with PTB.
Predetermination of Root Coverage
Authors: Zucchelli Giovanni , Mele Monica , Stefanini Martina , Mazzotti Claudio , Mounssif Ilham , Marzadori Matteo , Montebugnoli Lucio
Published: March 2010

Background: A method to predetermine the maximum root coverage level (MRC) achievable with surgery was recently presented. The present study evaluates the predictability of such a method by comparing the predetermined MRC with that effectively achieved by means of root coverage surgical procedures.

Methods: A total of 50 patients with single and multiple recession defects were enrolled. MRC was predetermined by an independent periodontist by assessing the ideal height of the interdental papilla. The distance from the apical reference point of a stent (StRP) and the MRC was measured 7 days before root coverage surgery. A total of 135 Miller Class I, II, and III gingival recessions were treated with the coronally advanced flap (CAF) or with the subepithelial connective tissue graft (SCTG). The distance from StRP and the gingival margin (GM) was measured by another independent periodontist 15, 30, and 90 days after surgery.

Results: In 97 (71.8%) of 135 treated gingival recessions, the StRP‐MRC distance coincided exactly with the StRP‐GM distance. No statistically significant difference was demonstrated in the cases with exact predetermination between gingival recessions belonging to the maxilla or mandible and between gingival defects treated with CAF or SCTG. The StRP‐MRC distance measured before surgery was greater in 24 recession defects (17.7%) and lower in 14 gingival recessions (10.3%) than the StRP‐GM distance measured 90 days after surgery. More cases of underestimation and fewer cases with overestimation of the level of root coverage were found in the SCTG group compared to the CAF group. The difference was statistically significant (P <0.01).

Conclusions: The adopted method was effective in predetermining the position of the soft tissue margin 90 days after root coverage surgery. The cases with underestimation of the level of root coverage should be considered clinically and esthetically successful.
The Role of Pantalar Arthrodesis in the Treatment of Paralytic Foot Deformities
Authors: Provelengios Stefanos , Papavasiliou Kyriakos A. , Kyrkos Margaritis J. , Sayegh Fares E. , Kirkos John M. , Kapetanos George A.
Published: March 2010

BACKGROUND:

Pantalar arthrodesis is considered by many to be the final operative option before amputation for the treatment of paralytic foot deformities. The aim of the present study was to evaluate the long-term results of pantalar arthrodesis with regard to its impact on the adjacent joints and the walking ability of patients with paralytic foot deformities.

METHODS:

Twenty-four patients (seventeen men and seven women) who underwent a one-stage pantalar arthrodesis between 1953 and 1973 for the treatment of sequelae of poliomyelitis were reevaluated. All patients underwent a physical and radiographic examination, and all completed the Short Form-36 questionnaire and a pantalar arthrodesis-specific questionnaire.

RESULTS:

The average age of the patients was twenty years at the time of the operation and 57.2 years at the time of the latest evaluation. The average duration of follow-up was 37.2 years. Eleven patients had development of immediate postoperative complications, including wound-healing problems (nine) and infections (two). The long-term results, however, were good (mean Short Form-36 scores, 73 of 100 points [overall], 51.5 points [physical functioning], and >70 points [all other domains]). Sixteen patients experienced repeated episodes of ipsilateral knee pain; most (fifteen) of these patients experienced a gradual onset of this pain, starting at an average of 20.8 years (range, fifteen to thirty years) postoperatively. The position of the fused ankle did not appear to have a significant impact on the development of ipsilateral knee pain or the time interval between the pantalar arthrodesis and the onset of ipsilateral knee pain.

CONCLUSIONS:

Pantalar arthrodesis effectively stabilizes the ankle, hindfoot, and midfoot in patients with severe paralytic deformities. Even though most patients can be expected to have development of osteoarthritis of the ipsilateral knee, it seems that a successfully performed pantalar arthrodesis in carefully selected cases is a reliable operative option offering a strong and stable foot that will function well for many years.

LEVEL OF EVIDENCE:

TherapeuticLevel IV. See Instructions to Authors for a complete description of levels of evidence.

ORIGINAL ABSTRACT CITATION:

“The Role of Pantalar Arthrodesis in the Treatment of Paralytic Foot Deformities. A Long-Term Follow-up Study” (2009;91:575-83).
Outcome of Lumbar Arthrodesis in Patients Sixty-five Years of Age or Older
Authors: Glassman Steven D. , Carreon Leah , Dimar John R.
Published: March 2010

BACKGROUND:

The value of lumbar spine arthrodesis in older patients is not well documented. As most of the literature regarding lumbar arthrodesis in older patients has focused on the prevalence of complications, the purpose of this study was to determine the clinical outcomes for older compared with younger patients undergoing lumbar arthrodesis.

METHODS:

We studied 224 patients who underwent a single-level posterolateral lumbar arthrodesis with an iliac crest bone graft. Outcome measures included the Oswestry Disability Index, the Medical Outcomes Study Short Form-36 and numeric rating scales for back and leg pain, as well as a radiographic assessment of fusion. Outcome measures were evaluated on the basis of the mean change and the percentage of patients reaching a minimum clinically important difference threshold. For comparison, the patients were divided into two groups: 174 patients who were younger than sixty-five years and fifty patients who were sixty-five years of age or older.

RESULTS:

Substantial improvements from baseline were noted in all of the clinical and health-related quality-of-life measures at the six-month, one-year, and two-year intervals. The mean improvements in the Oswestry Disability Index score at two years postoperatively were 28.5 points for the older patients and 24.5 points for the younger patients. For Short Form-36 physical component summary scores, the mean improvement from baseline was 14.2 points for the older group and 11.7 points for the younger group at two years. The older patients also demonstrated a similar or greater improvement in the numeric rating scale back and leg pain scores at all time intervals, with a significant difference in leg pain scores at two years postoperatively (10.4 points for the older patients and 6.4 points for the younger patients; p = 0.002). Perioperative complications, although an obvious concern, did not appear to adversely affect clinical and health-related quality-of-life outcomes at two years postoperatively.

CONCLUSIONS:

This study demonstrates a substantial benefit for patients sixty-five years of age or older with degenerative disc disease who are treated with a single-level lumbar decompression and instrumented arthrodesis, and we conclude that lumbar arthrodesis is a viable and reasonable treatment option for appropriately selected patients sixty-five years of age or older.

LEVEL OF EVIDENCE:

Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

ORIGINAL ABSTRACT CITATION:

“Outcome of Lumbar Arthrodesis in Patients Sixty-five Years of Age or Older” (2009;91:783-90).
Conversion of Painful Ankle Arthrodesis to Total Ankle Arthroplasty
Authors: Hintermann Beat , Barg Alexej , Knupp Markus , Valderrabano Victor
Published: March 2010

BACKGROUND:

Pain following an ankle arthrodesis continues to be a challenging clinical problem. Recent reports on semiconstrained two-component ankle implants have demonstrated the feasibility of reversing a problematic ankle fusion and converting it to a total ankle arthroplasty. However, the failure rate is high. The objective of the present prospective study was to evaluate the intermediate-term outcome associated with the use of an unconstrained three-component ankle implant after taking down an ankle arthrodesis.

METHODS:

Thirty painful ankles in twenty-eight patients (average age, 58.2 years) who were managed with takedown of a fusion and total ankle arthroplasty were followed for a minimum of thirty-six months (average, 55.6 months). The outcome was assessed on the basis of clinical and radiographic evaluations.

RESULTS:

In twenty-nine ankles in twenty-seven patients, the American Orthopaedic Foot and Ankle Society hindfoot score increased from 34.1 preoperatively to 70.6 at the time of the latest follow-up. Twenty-four patients (82.7%) were satisfied with the results. While five ankles were completely pain-free, twenty-one ankles were moderately painful, and three remained painful. The average clinically measured range of motion of 24.3° amounted to 55.1% of that of the contralateral, unaffected ankle. Radiographically, the tibial component was stable in all ankles but one. The talar component was found to have migrated in four ankles but was asymptomatic in two of them. One ankle had to be revised to a tibiocalcaneal arthrodesis because of persistent pain and loosening of the talar component.

CONCLUSIONS:

For patients with pain at the site of a failed ankle arthrodesis, conversion to total ankle arthroplasty with the use of a three-component ankle implant is a viable treatment option that provides reliable intermediate-term results. Key factors for the success of this procedure may be the intrinsic coronal plane stability provided by the ankle implants and the use of wider talar implants.

LEVEL OF EVIDENCE:

Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

ORIGINAL ABSTRACT CITATION:

“Conversion of Painful Ankle Arthrodesis to Total Ankle Arthroplasty” (2009;91:850–8).
Detection of drought events in Greece using daily precipitation
Authors: Kalamaras N. , Michalopoulou H. , Byun H. R.
Published: March 2010

In this study a method proposed by Byun & Wilhite, which estimates drought severity and duration using daily precipitation values, is applied to data from stations at different locations in Greece. Subsequently, a series of indices is calculated to facilitate the detection of drought events at these sites. The results provide insight into the trend of drought severity in the region. In addition, the seasonal distribution of days with moderate and severe drought is examined. Finally, the Hierarchical Cluster Analysis method is used to identify sites with similar drought features.
Employment among Older Workers and Inequality of Gender and Education: Evidence from a Taiwanese National Survey
Authors: Lu Luo
Published: March 2010

The aim of this research was twofold: to examine the prevalence of employment and under-employment among Taiwanese older workers (aged 50 and above), and to explore personal correlates of their employment status, in particular gender and education. Using a national representative sample, we found that: 1) a rather substantial percentage of people continued to work well into their older years; 2) the underemployment rates were substantial in the older age, and less-educated workers and women were more at risk; and 3) multivariate analysis confirmed that age, gender, personal health, spousal health, and family income were significant predictors of continued employment after age 50. Gender and education were also significantly related to the risk of under-employment. Our results highlight the importance and urgency of more concerted research to inform public labor policies, especially in an aging developing society where older workers are faced with a double challenge of economic and societal restructuring.
How it Matters When it Happens: Life Changes Related to Functional Loss in Younger and Older Adults
Authors: Boerner Kathrin , Wang Shu-Wen
Published: March 2010

This study examined the impact of loss of vision on important life domains depending on life context. The sample included two groups dealing with vision impairment: middle-aged ( n = 44) and older adults ( n = 107). Findings showed important group differences in extent, type, and facet of life changes across and within four life domains: goals/priorities, self-views, worldviews, and relationships with others. Overall, middle-aged participants experienced more change, and these changes seemed to be more pronounced. Findings suggest that if vision loss occurs in middle adulthood, it tends to be more disruptive, and that it comes with the risk of negative long-term consequences.
Perioperative Management of the Glucose-6-Phosphate Dehydrogenase Deficient Patient: A Review of Literature
Authors: Elyassi Cpt Ali R. , Rowshan Maj Henry H.
Published: March 2010

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymatic disorder of red blood cells in humans. It is estimated that about 400 million people are affected by this deficiency.1 The G6PD enzyme catalyzes the first step in the pentose phosphate pathway, leading to antioxidants that protect cells against oxidative damage.2 A G6PD-deficient patient, therefore, lacks the ability to protect red blood cells against oxidative stresses from certain drugs, metabolic conditions, infections, and ingestion of fava beans.3 The following is a literature review, including disease background, pathophysiology, and clinical implications, to help guide the clinician in management of the G6PD-deficient patient. A literature search was conducted in the following databases: PubMed, The Cochrane Library, Web of Science, OMIM, and Google; this was supplemented by a search for selected authors. Keywords used were glucose-6-phosphate dehydrogenase (G6PD) deficiency, anesthesia, analgesia, anxiolysis, management, favism, hemolytic anemia, benzodiazepines, codeine, codeine derivatives, ketamine, barbiturates, propofol, opioids, fentanyl, and inhalation anesthetics. Based on titles and abstracts, 23 papers and 1 website were identified. The highest prevalence of G6PD is reported in Africa, southern Europe, the Middle East, Southeast Asia, and the central and southern Pacific islands; however, G6PD deficiency has now migrated to become a worldwide disease. Numerous drugs, infections, and metabolic conditions have been shown to cause acute hemolysis of red blood cells in the G6PD-deficient patient, with the rare need for blood transfusion. Benzodiazepines, codeine/codeine derivatives, propofol, fentanyl, and ketamine were not found to cause hemolytic crises in the G6PD-deficient patient. The most effective management strategy is to prevent hemolysis by avoiding oxidative stressors. Thus, management for pain and anxiety should include medications that are safe and have not been shown to cause hemolytic crises, such as benzodiazepines, codeine/codeine derviatives, propofol, fentanyl, and ketamine. The authors of this article make 5 particular recommendations: (1) Anyone suspected of G6PD deficiency should be screened; (2) exposure to oxidative stressors in these individuals should be avoided; (3) these patients should be informed of risks along with signs and symptoms of an acute hemolytic crisis; (4) the clinician should be able to identify both laboratory and clinical signs of hemolysis; and finally, (5) if an acute hemolytic crisis is identified, the patient should be admitted for close observation and care.
Relevance of management and feeding regimens on life expectancy in captive deer
Authors: Müller Dennis W. H. , Lackey Laurie Bingaman , Streich W. Jürgen , Hatt Jean-Michel , Clauss Marcus
Published: March 2010

Objective—To establish a demographic approach to facilitate the comparison of husbandry success for deer species in zoos and to test for factors that influence the performance of deer species in captivity.

Sample Population—Data collected from 45,736 zoo-kept deer that comprised 31 species.

Procedures—Data had been collected by the International Species Information System during the last 3 decades on zoo-kept deer around the world. The relative life expectancy (rLE) of a species (ie, mean life expectancy as a proportion of the maximum recorded life span for that species) was used to describe zoo populations. The rLE (values between 0 and 1) was used to reflect the husbandry success of a species.

Results—A significant positive correlation was found between the rLE of a species and the percentage of grass in the natural diet of the species, suggesting that there are more problems in the husbandry of browsing than of grazing species. The 4 species for which a studbook (ie, record of the lineage of wild animals bred in captivity) was maintained had a high rLE, potentially indicating the positive effect of intensive breeding management.

Conclusion and Clinical Relevance—The rLE facilitated the comparison of husbandry success for various species and may offer the possibility of correlating this quotient with other biological variables. Ultimately, identifying reasons for a low husbandry success in certain species may form the basis for further improvements of animal welfare in captivity.
Computed tomography and cross-sectional anatomy of the head in healthy rabbits
Authors: Van Caelenberg Annemie I. , De Rycke Lieve M. , Hermans Katleen , Verhaert Leen , van Bree Henri J. , Gielen Ingrid M.
Published: March 2010

Objective—To obtain a detailed anatomic description of the rabbit head by means of computed tomography (CT).

Animals—6 clinically normal Dendermonde White rabbits weighing 3 kg and raised for human consumption and 1 Netherland dwarf rabbit.

Procedures—The commercially raised rabbits were slaughtered in a slaughterhouse, flayed, and decapitated. The dwarf rabbit was euthanatized. Two hours later, each rabbit head was positioned with the ventral side on the CT table to obtain transverse and sagittal, 1-mm-thick slices. Dorsal images were obtained by placing each head perpendicular to the table. Immediately after the CT examination, 3 heads were frozen in an ice cube at −14°C until solid and then sectioned at 4-mm-thick intervals by use of an electric band saw. Slab sections were immediately cleaned, photographed, and compared with corresponding CT images. Anatomic sections were examined, and identified anatomic structures were matched with structures on corresponding CT images.

Results—The bone-window CT images yielded good anatomic detail of the dentition and the bony structures of rabbit skulls. The soft tissue structures that could be determined were not better identifiable on the soft tissue–window CT images than on the bone-window images.

Conclusions and Clinical Relevance—CT images of the heads of healthy rabbits yielded detailed information on the skull and some surrounding soft tissue structures. Results of this study could be used as a guide for evaluation of CT images of rabbits with various cranial and dental disorders.
Evaluation of the effect of signalment and body conformation on activity monitoring in companion dogs
Authors: Brown Dorothy Cimino , Michel Kathryn E. , Love Molly , Dow Caitlin
Published: March 2010

Objective—To evaluate the effect of signalment and body conformation on activity monitoring in companion dogs.

Animals—104 companion dogs.

Procedures—While wearing an activity monitor, each dog was led through a series of standard activities: lying down, walking laps, trotting laps, and trotting up and down stairs. Linear regression analysis was used to determine which signalment and body conformation factors were associated with activity counts.

Results—There was no significant effect of signalment or body conformation on activity counts when dogs were lying down, walking laps, and trotting laps. However, when dogs were trotting up and down stairs, there was a significant effect of age and body weight such that, for every 1-kg increase in body weight, there was a 1.7% (95% confidence interval, 1.1% to 2.4%) decrease in activity counts and for every 1-year increase in age, there was a 4.2% (95% confidence interval, 1.4% to 6.9%) decrease in activity counts.

Conclusions and Clinical Relevance—When activity was well controlled, there was no significant effect of signalment or body conformation on activity counts recorded by the activity monitor. However, when activity was less controlled, older dogs and larger dogs had lower activity counts than younger and smaller dogs. The wide range in body conformation (eg, limb or body length) among dogs did not appear to significantly impact the activity counts recorded by the monitor, but age and body weight did and must be considered in analysis of data collected from the monitors.
Levetiracetam pharmacokinetics in healthy dogs following oral administration of single and multiple doses
Authors: Moore Sarah A. , Muñana Karen R. , Papich Mark G. , Nettifee-Osborne Julie
Published: March 2010

Objective—To measure pharmacokinetics of levetiracetam (LEV) after single-dose oral administration in healthy dogs and determine whether pharmacokinetics changed after repeated oral dosing.

Animals—6 healthy adult dogs.

Procedures—Pharmacokinetics were calculated following administration of a single dose (mean, 21.7 mg/kg, PO; day 1) and after administration of the last dose following administration for 6 days (20.8 to 22.7 mg/kg, PO, q 8 h; days 2 to 7). Plasma LEV concentrations were determined by use of high-pressure liquid chromatography. Pharmacokinetic data were analyzed by use of a 1-compartment model with first-order absorption.

Results—Peak concentration occurred 0.6 hours after administration of the first dose, with an absorption half-life of 0.06 hours. Minimal accumulation occurred over the 7 days, with only a slight increase in total area under the concentration-versus-time curve from 268.52 ± 56.33 h·μg/mL (mean ± SD) to 289.31 ± 51.68 h·μg/mL after 7 days. Terminal half-life was 2.87 ± 0.21 hours after the first dose and 3.59 ± 0.82 hours after the last dose on day 7. Trough plasma concentrations were variable, depending on the time of day they were measured (morning trough concentration, 18.42 ± 5.16 μg/mL; midday trough concentration, 12.57 ± 4.34 μg/mL), suggesting a diurnal variation in drug excretion.

Conclusions and Clinical Relevance—Results indicated that the pharmacokinetics of LEV did not change appreciably after administration of multiple doses over 7 days. Administration of LEV at a dosage of 20 mg/kg, PO, every 8 hours to healthy dogs yielded plasma drug concentrations consistently within the therapeutic range established for LEV in humans.
A comparison of in situ and in vitro techniques for bursting pressure testing of canine jejunum
Authors: Curran Kaitlin M. , Fransson Boel A. , Gay John M.
Published: March 2010

Objective—To compare bursting pressures in canine jejunum, measured by use of an in vitro and an in situ bursting pressure technique.

Study Population—Cadavers of 3 healthy adult dogs.

Procedures—54 enterotomies were performed on 3 canine cadavers immediately after euthanasia. After completion of enterotomy closure, bursting pressure was measured on 9 jejunal segments by use of an in situ technique and on 9 jejunal segments by use of an in vitro technique for each canine cadaver. Bursting pressure testing time was recorded for both in situ and in vitro techniques. Techniques were compared by means of randomized block ANOVA.

Results—The mean ± SE in vitro and in situ bursting pressures were 93.63 ± 24.10 mm Hg and 141.19 ± 38.10 mm Hg and were not significantly different. Mean in situ testing time was 40.7 min/cadaver; mean in vitro testing time was 50.3 min/cadaver.

Conclusions and Clinical Relevance—The in situ bursting pressure testing technique yielded results similar to those of the in vitro method, was somewhat less labor-intensive, and may be applicable to future studies of live dogs.
A multicenter study of the effect of dietary supplementation with fish oil omega-3 fatty acids on carprofen dosage in dogs with osteoarthritis
Authors: Fritsch Dale A. , Allen Timothy A. , Dodd Chadwick E. , Jewell Dennis E. , Sixby Kristin A. , Leventhal Phillip S. , Brejda John , Hahn Kevin A.
Published: March 2010

Objective—To determine the effects of feeding a diet supplemented with fish oil omega-3 fatty acids on carprofen dosage in dogs with osteoarthritis.

Design—Randomized, controlled, multisite clinical trial.

Animals—131 client-owned dogs with stable chronic osteoarthritis examined at 33 privately owned veterinary hospitals in the United States.

Procedures—In all dogs, the dosage of carprofen was standardized over a 3-week period to approximately 4.4 mg/kg/d (2 mg/lb/d), PO. Dogs were then randomly assigned to receive a food supplemented with fish oil omega-3 fatty acids or a control food with low omega-3 fatty acid content, and 3, 6, 9, and 12 weeks later, investigators made decisions regarding increasing or decreasing the carprofen dosage on the basis of investigator assessments of 5 clinical signs and owner assessments of 15 signs.

Results—Linear regression analysis indicated that over the 12-week study period, carprofen dosage decreased significantly faster among dogs fed the supplemented diet than among dogs fed the control diet. The distribution of changes in carprofen dosage for dogs in the control group was significantly different from the distribution of changes in carprofen dosage for dogs in the test group.

Conclusions and Clinical Relevance—Results suggested that in dogs with chronic osteoarthritis receiving carprofen because of signs of pain, feeding a diet supplemented with fish oil omega-3 fatty acids may allow for a reduction in carprofen dosage.
Use of a constant rate infusion of insulin for the treatment of hyperglycemic, hypernatremic, hyperosmolar syndrome in an alpaca cria
Authors: Buchheit Teresa M. , Sommardahl Carla S. , Frank Nicholas , Roberson Jerry R.
Published: March 2010

Case Description—A 3-day-old 9.5-kg (21-lb) female alpaca cria was examined because of lethargy and anorexia.

Clinical Findings—Physical examination revealed hyperthermia, muscle fasciculations, and tremors of the head. Seizures were also observed, which indicated CNS dysfunction. Hyperosmolar syndrome (HOS) was diagnosed on the basis of hyperglycemia, hypernatremia, azotemia, high plasma osmolarity, and metabolic acidosis.

Treatment and Outcome—A constant rate infusion of regular insulin was administered with hypo-osmolar fluids to treat HOS, and blood glucose and sodium concentrations were successfully lowered. Neurologic deficits resolved with treatment, and the cria was discharged 11 days after admission.

Clinical Relevance—Administration of insulin as a bolus in addition to hypo-osmolar fluids has been advocated in the management of neonatal camelids with HOS. Administration of regular insulin via a constant rate IV infusion was used to successfully manage a neonatal camelid with HOS. This form of insulin administration may allow more control of glucose kinetics in these patients.
Simulation of dissociation of DNA duplexes attached to the surface
Authors: Zhdanov Vladimir , Gunnarsson Anders , Höök Fredrik
Published: March 2010

We present Monte Carlo simulations of dissociation of duplexes formed of complementary single-stranded DNAs with one of the strands attached to the surface. To describe the transition from the bound state to the unbound state of two strands located nearby, we use a lattice model taking DNA base-pair interactions and comformational changes into account. The results obtained are employed as a basis for a more coarse-grained model including strand backward association and diffusion resulting in complete dissociation. The distribution of the dissociation time is found to be exponential. This finding indicates that the non-exponential kinetic features observed in the corresponding experiments seem to be related to extrinsic factors, e.g., to the surface heterogeneity.
Activation of the Shoulder Musculature During Pendulum Exercises and Light Activities
Authors: Long Joy L. , Ruberte Thiele Ramon A. , Skendzel Jack G. , Jeon Jongeun , Hughes Richard E. , Miller Bruce S. , Carpenter James E.
Published: March 2010

Study Design

Prospective, single-group, repeated-measures design.

Objectives

To evaluate electromyographic (EMG) signal amplitude in the supraspinatus, infraspinatus, and deltoid muscles during pendulum exercises and light activities in a group of healthy subjects.

Background

There are numerous rehabilitation protocols used after rotator cuff repair. One of the most commonly used exercises in these protocols is the pendulum. Patients can easily perform these exercises incorrectly, and may also perform light activities of daily living without knowing that they may be putting excessive stress on the repair. The effect of improperly performed pendulum exercises and light activities after rotator cuff repair is unknown.

Methods

Muscle activity was recorded in 13 subjects performing pendulum exercises incorrectly and correctly in both large (51-cm) and small (20-cm) diameters, and while typing, drinking, and brushing their teeth.

Results

Incorrect and correct large pendulums and drinking elicited more than 15% maximum voluntary isometric contraction in the supraspinatus and infraspinatus. The supraspinatus EMG signal amplitude was greater during large, incorrectly performed pendulums than during those performed correctly. Both correct and incorrect large pendulums resulted in statistically higher muscle activity in the supraspinatus than the small pendulums.

Conclusion

Larger pendulums may require more force than is desirable early in rehabilitation after rotator cuff repair. J Orthop Sports Phys Ther 2010;40(4):230–237. doi:10.2519/jospt.2010.3095
Thermo-mechanical Properties of Urea-based Pattern Molding Compounds for Investment Casting
Authors: Rutto H. , Focke W. W.
Published: March 2010

Urea is a low cost material with thermal and mechanical properties suitable for use in investment casting pattern molding compounds. Conventional compounds are made by a “cooking” process wherein the urea is added to and dissolved in an aqueous solution of a water soluble polymer followed by evaporation of the water. Here we describe novel formulations based on either polyvinyl alcohol (PVOH) plasticized by glycerol or ethylene vinyl acetate (EVA) resins together with wax that can be prepared by a facile twin-screw compounding process. The thermo-mechanical properties of these compounds were characterized using differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), dynamic mechanical analysis (DMA) and three bend point tests. The PVOH-based molding compounds featured better mechanical properties than those based on EVA. Increasing the polymer content produced weaker but tougher molding compounds. Increasing wax content improved stiffness but resulted in a loss of toughness. The TG results showed that both compounds decomposed readily at elevated temperatures and left less than 3 wt.% ash at 800°C.
Erosion Wear Analysis of SiC Filled Glass-Epoxy Composites using Taguchi Technique
Authors: Biswas S. , Satapathy A.
Published: March 2010

This paper describes the processing of a class of hybrid composites prepared by filling of SiC particulates in glass fiber reinforced epoxy resin. Experiments are conducted to study the solid particle erosion response of these composites. A theoretical model for the wear rate of the composites during solid particle impact erosion is proposed for predictive purpose. The validity of the theoretical model is assessed with experimental results and the influence of control factors like impingement angle, impact velocity, erodent temperature, erodent size, stand-off distance and filler content etc. on wear rate is studied. For this purpose a novel technique like Taguchi experimental design is employed. It is observed that the erodent temperature, filler content, impact velocity, impingement angle are the most significant factors effecting the erosion rate. The peak erosion rate is found to be occurring at an impingement angle of 75°. The morphology of eroded surfaces is examined by using scanning electron microscopy (SEM) and possible erosion mechanisms are discussed.
Occipitocervical instrumentation in the pediatric population using a custom loop construct: initial results and long-term follow-up experience
Authors: Couture Daniel , Avery Nathan , Brockmeyer Douglas L.
Published: March 2010

Object

Rigid occipitocervical instrumentation for craniovertebral instability is gaining widespread acceptance for use in pediatric patients; however, most of the instrumentation has been modified from adult-sized hardware. The Wasatch loop system (formerly the Avery-Brockmeyer-Thiokol loop system) is a rigid occipitocervical fixation device designed specifically for use in children. It affixes to the occiput and incorporates either C1–2 transarticular screws or C-2 pars screws. It is preformed and is available in a variety of sizes. The authors describe their clinical experience and long-term follow-up experience with the first 22 patients.

Methods

An institutional review board–approved retrospective review of medical records and radiographs was performed for patients who underwent occipitocervical fusion with the Wasatch loop. The mean patient age was 4.9 years (1.2–13 years), and the overall mean follow-up was 4 years (1.5–6.5 years). Six patients had posttraumatic instability, and 16 patients had congenital instability.

Results

Twelve patients underwent placement of bilateral C1–2 transarticular screws, 6 patients had placement of a combination of C1–2 transarticular and C-2 pars screws, and 4 patients had placement of bilateral C-2 pars screws. One patient required a halo orthosis; the others were treated postoperatively with a hard cervical collar. All patients had radiographic evidence of solid occipitocervical arthrodesis on last follow-up examination.

Conclusions

The Wasatch loop system is a novel internal fixation device for children who have posttraumatic or congenital occipitocervical instability. Successful arthrodesis was achieved in all patients with minimal use of halo orthoses.
Endoscopic biopsy of brain tumors in children: diagnostic success and utility in guiding treatment strategies
Authors: Ahn Edward S. , Goumnerova Liliana
Published: March 2010

Object

Endoscopic biopsy is an important minimally invasive method of diagnosis in the initial management of lesions in children with intraventricular and periventricular tumors. The procedure can be performed in conjunction with CSF-diverting procedures for obstructive hydrocephalus. The authors present their single-institution experience in a predominantly pediatric series with respect to diagnostic efficacy, utility in guiding treatment plans, and safety.

Methods

A retrospective review was conducted in a consecutive series of patients who underwent endoscopic biopsy of brain tumors during a 13-year period.

Results

There were 33 endoscopic biopsies in 31 patients (16 males and 15 females). The average age of the patients was 11.3 years, with a mean follow-up duration of 2.4 years. The majority of biopsies were performed in conjunction with CSF-diverting procedures, such as endoscopic third ventriculostomy or fenestration of the septum pellucidum. Overall, 23 (70%) of 33 biopsies were diagnostic, with results that directed subsequent treatment. When stratified by tumor location, biopsy samples obtained in the lateral ventricle or pineal region were more favorable toward a successful diagnosis than those in the thalamus or tectal region. In 4 cases, elevated CSF tumor marker levels led to modification of the diagnosis and appropriate adjustment of treatment. The endoscopic third ventriculostomy success rate was 82.4%. There were 2 major complications (6.1%), which resulted in neurological deficits. There were no procedure-related deaths.

Conclusions

Endoscopic biopsy is an effective means of diagnosis of brain tumors in children. The diagnostic power may be more favorable with tumors in the lateral ventricle or pineal region. Collection of CSF during the procedure for tumor marker analysis is an integral component of diagnosis.
Endoscopic third ventriculostomy in patients with a diminished prepontine interval
Authors: Souweidane Mark M. , Morgenstern Peter F. , Kang Sungkwon , Tsiouris Apostolos John , Roth Jonathan
Published: March 2010

Object

Fenestration of the floor of the third ventricle is vital to the success of endoscopic third ventriculostomy (ETV) in treating patients with noncommunicating hydrocephalus. A generous prepontine interval (PPI) is generally accepted as one anatomical feature that may affect the safety and functionality of ETV. Whether a diminished PPI influences the safety or success of ETV, however, has not been adequately assessed.

Methods

A review was conducted on the last 100 ETV procedures performed by the first author (M.M.S.). From archived preoperative MR imaging studies, the PPI was measured between the dorsum sellae and the basilar artery. For any patient with an interval of ≤1 mm, the technical and functional success of the procedure was recorded. Technical success was defined when a surgically created fenestration was accomplished without patient morbidity. Functional success was defined as the patient not needing any additional CSF diversionary procedure within 3 months after ETV.

Results

In the entire cohort, the PPI ranged from 0 to 9.5 mm (mean 3.2 mm). There were 15 procedures performed in patients with a PPI of ≤1 mm. In all 15 procedures, a fenestration of the tuber cinereum was accomplished without vascular injury or patient morbidity. The ETV was successful in 11 patients (73.3%). All 4 failures occurred in children who had surgery during infancy (mean age 11 months).

Conclusions

Patients with an obliterated or reduced PPI can safely undergo ETV. The functional success rate appears equivalent to historical controls. Most failures in this series may be attributed to other patient characteristics, namely young age at the time of ETV.
Long-term neuropsychological development in single-suture craniosynostosis treated early
Authors: Chieffo Daniela , Tamburrini Gianpiero , Massimi Luca , Di Giovanni Simona , Giansanti Cristina , Caldarelli Massimo , Di Rocco Concezio
Published: March 2010

Object

The authors evaluated the results of complete cognitive function examinations in a series of 65 adolescents who had undergone surgery for sagittal or unicoronal craniosynostosis when they were younger than 1 year old.

Methods

Each of the 65 study participants was evaluated individually. The neuropsychological assessment, consisting of a battery of tests tailored to the patient's age, cognitive level, and level of cooperation, was conducted in 2 separate sessions on the same day. The main outcome measures included fine motor skills, language, visual motor spatial and visual perceptual skills, working and visual memory, attention, executive function, and verbal fluency.

Results

Thirty-five children (mean age 13.4 years) were affected by sagittal synostosis and 30 (mean age 14.9 years) by unicoronal synostosis (16 right-sided, 14 left-sided). The mean age at surgery was 7.2 months. All of the children had begun school at a normal age and attended regular classes. Seven percent of those with sagittal craniosynostosis demonstrated visuospatial and constructional ability defects with associated visual memory recall deficits; 17% also exhibited selective and sustained attention deficits. Approximately one-third (30%) of the children with anterior plagiocephaly had processing and planning speech deficits.

Conclusions

Data in this study support the hypothesis that children with sagittal or unicoronal craniosynostosis, although they undergo early surgical treatment, may still manifest lower than average results at long-term selective neuropsychological evaluations.