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Biomedical subjects

C Anglin

Publications and source records attributed to C Anglin.

At least 19 recordsLinked to original sources
PubMed2006

Success factors for telehealth--a case study.

PURPOSE: To present the lessons learned from an evaluation of a comprehensive telehealth project regarding success factors and evaluation methodology for such projects. METHODS: A recent experience with the evaluation of new telehealth services in BC, Canada, is summarized. Two domains of clinical applications, as well as educational and administrative uses, and the project environment were evaluated. In order to contribute to the success of the project, the evaluation included formative and summative approaches employing qualitative and quantitative methods with data collection from telehealth events, participants and existing databases. The evaluation had to be carried out under severe budgetary and time constraints. We therefore deliberately chose a broad ranging exploratory approach within a framework provided, and generated questions to be answered on the basis of initial observations and participant driven interviews with progressively more focused and detailed data gathering, including perusal of a variety of existing data sources. A unique feature was an economic evaluation using static simulation models. RESULTS: The evaluation yielded rich and detailed data, which were able to explain a number of unanticipated findings. One clinical application domain was cancelled after 6 months, the other continues. The factors contributing to success include: Focus on chronic conditions which require visual information for proper management. Involvement of established teams in regular scheduled visits or in sessions scheduled well in advance. Problems arose with: Ad hoc applications, in particular under emergency conditions. Applications that disregard established referral patterns. Applications that support only part of a unit's services. The latter leads to the service mismatch dilemma (SMMD) with the end result that even those e-health services provided are not used. The problems encountered were compounded by issues arising from the manner in which the telehealth services had been introduced, in particular the lack of time for preparation and establishment of routine use. Educational applications had significant clinical benefits. Administrative applications generated savings which exceeded the substantial capital investment and made educational and clinical applications available at variable cost. CONCLUSION: Evaluation under severe constraints can yield rich information. The identified success factors, including provision of an overarching architecture and infrastructure, strong program management, thorough needs analysis and detailing applications to match the identified needs should improve the sustainability of e-health projects. Insights gained: Existing assumptions before the study was conducted: Evaluation has to proceed from identified questions according to a rigorous experimental design. Emergency and trauma services in remote regions can and should be supported via telehealth based on video-conferencing. Educational applications of telehealth directed at providers are beneficial for recruitment and retention of providers in remote areas. Insights gained by the study: An exploratory approach to evaluation using a multiplicity of methods can yield rich and detailed information even under severe constraints. Ad hoc and emergency clinical applications of telehealth can present problems unless they are based on thorough, detailed analyses of environment and need, conform to established practice patterns and rely on established trusting collaborative relationships. Less difficult applications should be introduced before attempting to support use under emergency conditions. Educational applications are of interest beyond the provider community to patients, family and community members, and have clinical value. In large, sparsely populated areas with difficult travel conditions administrative applications by themselves generate savings that compensate for the substantial capital investment for telehealth required for clinical applications.

British Columbia↗
PubMed2006

Lest formalisms impede insight and success: evaluation in health informatics--a case study.

OBJECTIVES: To illustrate the advantages of an open-ended formative evaluation approach using a project-specific selection of methods over the controlled trial approach in the evaluation of health information systems. To illustrate factors leading to success and others impeding it in a telehealth project. METHODS: The methods and results of an evaluation of the BC Telehealth Program are summarized. RESULTS: The evaluation gave a comprehensive picture of the project, including assessment of the effects of an array of telehealth applications, and their economic impact. Factors leading to success and others preventing it are identified from the level of overall program management to the project specifics. The results include unanticipated effects and explanations for their reasons of occurrence. Neither the comprehensiveness of information nor the timeliness was achieved in a related project using a controlled trial approach. CONCLUSIONS: Not all types of health information system projects can be evaluated using the controlled trial approach. This approach may impede important insights. It is also usually much less efficient. Funding agencies and journal editors have to take this into account when selecting projects for funding and submissions for publication.

British Columbia↗
PubMed2003

Influence of peg design and cement mantle thickness on pull-out strength of glenoid component pegs.

Fixation of the glenoid component is critical to the outcome of total shoulder arthroplasty. In an in vitro study, we analysed the effect of surface design and thickness of the cement mantle on the pull-out strength of the polyethylene pegs which are considered essential for fixation of cemented glenoid components. The macrostructure and surface of the pegs and the thickness of the cement mantle were studied in human glenoid bone. The lowest pull-out forces, 20 +/- 5 N, were for cylindrical pegs with a smooth surface fixed in the glenoid with a thin cement mantle. The highest values, 425 +/- 7 N, were for threaded pegs fixed with a thicker cement mantle. Increasing the diameter of the hole into which the peg is inserted from 5.2 to 6.2 mm thereby increasing the thickness of the cement mantle, improved the mean pull-out force for the pegs tested.

Arthroplasty, Replacement↗
PubMed2001

Loosening performance of cemented glenoid prosthesis design pairs.

OBJECTIVE: The purpose of this pilot study (n=3) was to compare the loosening performance of glenoid prosthesis design pairs where only one design variable differed. DESIGN: Glenoids were subjected to dynamic edge loading in a biaxial test setup. BACKGROUND: Glenoid component loosening is the primary concern in total shoulder arthroplasty. METHODS: After the humeral head was cycled 100,000 times to the superior and inferior edges of the glenoid, the tensile edge displacements were measured under superior and inferior off-center loading. RESULTS AND CONCLUSIONS: Based on this study, a rough-backed design had dramatically better loosening performance than a smooth-backed; curved-backed was superior to flat-backed; a less-constrained articular surface was better than a more-constrained articular surface; pegs outperformed a keel; threaded pegs were marginally preferable to cylindrical pegs; and an all-polyethylene design rocked slightly less than a metal-mesh-backed design. RELEVANCE: A comparison of the laboratory loosening behavior of glenoid prostheses may lead to improved designs, subsequently leading to a reduction in the incidence of clinical loosening.

Biomechanical Phenomena↗
PubMed2000

Arm motion and load analysis of sit-to-stand, stand-to-sit, cane walking and lifting.

OBJECTIVE: To conduct a pilot study to characterize the hand loads, arm joint angles and external moments corresponding to five activities of daily living demanding of the shoulder, for healthy subjects over 50 years of age. DESIGN: The tasks were sit-to-stand, stand-to-sit, cane walking, lifting a 5 kg box with both hands, and lifting a 10 kg suitcase. BACKGROUND: Arm motion and loading have not been previously studied for functional daily-living tasks involving substantial external loads.Methods. Motion was tracked using an optoelectronic system. Loads were measured using an instrumented chair arm, a force plate, and gravitational and acceleration loads. Six healthy volunteers (3 male, 3 female), mean age 55, with no history of shoulder problems participated in the study. RESULTS: Average peak external moments ranged from 12.3 N m for sitting down into a chair to 27.9 N m for lifting a suitcase. Except for lifting the box, which had much lower loads, average peak hand loads varied from 16% to 19% of body weight (114-134 N). The arcs of motion were larger than for seated activities of daily-living studied previously. CONCLUSIONS: The five tasks studied are commonly performed, yet involve large external moments. Lifting represents the greatest potential loading at the shoulder as it resulted in the highest external moments; furthermore, loads larger than those used in this study might be commonly lifted. RELEVANCE: External moments at the shoulder should not be underestimated, even for activities of daily living.

Activities of Daily Living↗
PubMed2000

Review of arm motion analyses.

Interest in arm movements has increased tremendously in recent years. This interest has been motivated by different goals: the desire for a more scientific approach to replacement or support of the joints of the upper limb, the need for input to biomechanical computer models, and the clinical interest in comparing normal movements with pathological movements. The availability of commercial marker-tracking systems has facilitated achieving these goals. However, the complex nature of arm movements and the lack of standardized movements raises many challenges. In comparison with gait analysis, few arm motion analyses have been conducted. The purpose of this review is to aid researchers and clinicians interested in conducting an arm motion study in choosing the appropriate methodology. This is accomplished both by describing the methods used in past investigations and by highlighting important findings. Due to the variety of research goals, there is sometimes more than one appropriate method and the choice is left to the reader. Nevertheless, since it is extremely desirable to record and express the data in a standardized way, standardization proposals are described. This review, which focuses on methodology rather than results, addresses the following topics: motivations and tasks studied, tracking methods, the shoulder complex, joint centres and rotation axes, marker positions, coordinate system definitions, terminology and rotations, accuracy, and presentation methods.

Activities of Daily Living↗
PubMed2000

Glenohumeral contact forces.

Glenohumeral contact forces have only been calculated previously either for simple abduction or for athletic activities. The objective of this study was to determine the glenohumeral contact forces for tasks which are demanding of the shoulder but which would commonly be performed by older people. The functional tasks chosen were using the arms to stand up from and sit down into a chair, walking with a cane, lifting a 5 kg box to shoulder height with both hands, and lifting a 10 kg suitcase. The trunk angles, arm angles and hand loads of six healthy subjects, average age 55 years, were recorded. This information was input into a biomechanical computer model which optimized the muscle force distribution by minimizing the sum of squared muscle stresses subject to constraints on the maximum muscle forces and maintaining the direction of the resultant force within the glenoid fossa. Average contact forces ranged from 1.3 to 2.4 times body weight (930-1720 N), the highest force being for lifting a suitcase. This latter value would be even higher if lifting either a greater load or to a greater height. Thus, contact forces at the shoulder should not be underestimated. This study provides functionally relevant contact forces which can be used for mechanical testing or finite element modelling of shoulder prostheses.

Activities of Daily Living↗
PubMed1999

Glenoid cancellous bone strength and modulus.

The objectives of this study were to determine the strength and modulus of glenoid cancellous bone, including regional variations. The motivations were: to select a suitable bone substitute for standardized testing of glenoid prosthesis loosening, to assist in shoulder prosthesis design and to provide input data for finite element analyses. Ten glenoids from eight cadavers (mean age, 81) were tested by in situ indentation. Mean strength ranged from 6.7 to 17 MPa for the ten glenoids, the overall mean being 10.3 MPa. Mean E moduli ranged from 67 to 171 MPa for the individual glenoids, the overall mean being 99 MPa. These values are likely at the lower end of what would be expected for normal bone since strength and modulus decrease with age and the available specimens were older. These values may be appropriate for prosthesis design, however, since mechanical properties are reduced in rheumatoid arthritic bone. Regional trends were very similar for modulus and strength. The strongest region was postero-superior. The central column, correlating with the keel position in many glenoid components, was weaker than both the anterior and posterior regions but deeper. A large drop in strength and modulus below the subchondral layer emphasizes the importance of maintaining this layer during prosthetic replacement.

Aged↗
PubMed1995

Eicosanoids and histamine mediate C5a-induced electrolyte secretion in guinea pig ileal mucosa.

C5a is a biologically active polypeptide formed during the course of complement activation and is known to possess histamine-releasing and neutrophil chemotactic properties. In the present study, we have demonstrated that C5a can regulate electrolyte transport across guinea pig ileum, and we have investigated its mechanism of action. Segments of ileum stripped of longitudinal muscle were mounted in Ussing chambers (Krebs' buffer, 37 degrees C, 95% O2/5% CO2) for monitoring short-circuit current (Isc). Serosal application of C5a evoked a transient increase in Isc with an EC50 value of 5.0 nM indicating a potent effect. The C5a-induced increase in Isc was abolished by elimination of both Cl- and HCO3- from the Krebs' solution. Pretreatment with the cyclooxygenase inhibitor indomethacin (5 microM), the neurotoxin tetrodotoxin (0.5 microM) and the H1 receptor antagonist pyrilamine (0.5 microM) reduced the effect of C5a, but the muscarinic antagonist atropine (0.5 microM) was without effect. C5a (100 nM) also evoked the release of histamine (measured by radioimmunoassay in the serosal bathing fluid) by 282% of the control value. In conclusion, in the guinea pig ileum C5a stimulates mucosal anion secretion by releasing histamine and cyclooxygenase products of arachidonic acid. The response is also mediated, in part, via non-chloinergic enteric nerves.

Animals↗
PubMed1993

Inflammatory mediator changes in cotton-top tamarins (CTT) after SC-41930 anti-colitic therapy.

Use of the CTT model provides insight into the inflammatory mediator contribution in the pathogenesis of idiopathic colitis. To evaluate anti-colitic efficacy, the leukotriene B4 receptor antagonist and anti-inflammatory agent, SC-41930, was administered (10 mg/kg BW by gavage BID) for 8 weeks to CTTs with histologically confirmed persistent and defined active colitis. The inflammatory mediators LTB4, PGE2, TXB2, and PAF were assayed in colonic dialysate that was collected after 1 1/2 h from four CTTs pre-, mid-, and post-treatment, frozen at -70 degrees C, and analyzed by RIA after HPLC purification. LTB4 levels were lower at mid- and post-treatment and had little inter-animal variation post-treatment. PGE2 and PAF levels were elevated during SC-41930 treatment, but there was a trend towards lower thromboxane B2 levels. Reduced LTB4 (PMN degranulation and chemotaxis) and increased PGE2 (mucosal-protective effect) may, in part, explain the observed efficacy of SC-41930 in active tamarin colitis.

Animals↗
PubMed1990

CD 18 monoclonal antibody inhibits neutrophil diapedesis in the murine dermis induced by leukotriene B4 and 12(R)-hydroxyeicosatetraenoic acid.

Neutrophil accumulation is a hallmark of the inflammatory process. The ability of neutrophils to release lipid mediators, toxic oxygen metabolites, proteolytic enzymes and cationic proteins may contribute to the tissue pathology seen in inflammatory diseases such as inflammatory bowel disease and psoriasis. The first step in the process of neutrophil diapedesis in a gradient of chemoattraction is adhesion to the microvascular endothelium, a phenomenon mediated by the stimulated activation of the neutrophil CD11a-c/CD18 cell surface glycoprotein complex. We assessed the ability of a monoclonal antibody (MoAb) (hybridoma: SP2/0-Ag. 14XBALB/c spleen cells; isotype: murine IgG1) to CD18 that recognizes the beta chain of LFA1(CD11a/CD18), MAC-1(CD11b/CD18) and CD11c/CD18 to effect the neutrophils response to the proinflammatory chemotaxins leukotriene B4 (LTB4) and 12(R)-hydroxy-5,8,11,14-eicosatetraenoic acid [12(R)-HETE] in the mouse dermis. LTB4 and 12(R)-HETE induce a time and concentration dependent infiltration of s when applied intradermally. LTB4 (100 ng) and 12(R)-HETE (50 micrograms) were injected intradermally in CD-mice (18 g body weight) and assessed for chemotactic activity four h later by the dermal levels of myeloperoxidase (MPO), a neutrophil marker enzyme. CD18 MoAb(0.02 mg) was given intravenously 10 min ahead of dermal chemotaxin injection. LTB4 increased (p less than .01) dermal levels of MPO at 4 h, a neutrophil accumulation inhibited (p less than .005) by CD18 MoAb pretreatment (Mean MPO +/- SEM: Vehicle, 0.049 +/- 0.006U vs LTB4, 0.309 +/- 0.033U vs MoAb, 0.137 +/- 0.012U) (n = 12/group).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines as potential inhibitors of H+/K+ ATPase.

A series of substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines were synthesized as potential inhibitors of the acid secretory enzyme H+/K+ ATPase. Substitutions on the aniline nitrogen atom resulted in potent enzyme inhibition in vitro but weak activity in gastric fistula dogs. Electron-donating substituents on the aniline ring enhanced in vitro and in vivo potency relative to the unsubstituted analogue. The potency showed a correlation to the calculated pKa of the aniline nitrogen atom. Substitutions on the aniline and benzimidazole rings did not further enhance potency. Di- and trisubstituted aniline derivatives were potent inhibitors of the enzyme system. The preferred combination of substituents were a methoxy group on the benzimidazole ring and a single alkyl group on the aniline ring. One such compound, 76, was an effective inhibitor of acid secretion in the dog and was selected for further pharmacological study.

Adenosine Triphosphatases↗
PubMedDate not supplied

Mechanical testing of shoulder prostheses and recommendations for glenoid design.

Glenoid component loosening generates the greatest concern among surgeons performing total shoulder arthroplasty. Laboratory testing of glenoid prostheses may lead to improved design, subsequently leading to a reduction in the incidence of clinical loosening. The goals of this study were to develop a laboratory test method to address glenoid loosening and to apply this method to a variety of prosthesis designs. With use of a biaxial apparatus, glenoid components were cyclically subjected to superoinferior edge loading, mimicking the off-center rocking-horse phenomenon thought to contribute to glenoid loosening clinically. Before and after the rocking test was performed, compression and distraction of the superior and inferior edges were measured with the humeral head displaced to each edge. Rocking performance could not be predicted from initial measurements, indicating the necessity for dynamic loading to evaluate the likelihood of loosening. A roughened fixation surface for outperformed a smooth fixation surface, a curved backing showed almost half the distraction of a flat backing, and a nonconstrained prosthesis distracted less than a more constrained prosthesis.

Arthroplasty↗