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Biomedical subjects

H Farris

Publications and source records attributed to H Farris.

6 recordsLinked to original sources

Bone formation into surface phosphonylated polymeric implants.

Through the use of two animal models, the present study demonstrates the ability of phosphonylated surfaces to bind bone. In one model, surface-treated polypropylene (PP) and polyethylene (PE) were implanted in the medial cortex of the goat tibia. In the second model, surface-treated poly(ether-ether ketone) (PEEK) and carbon fiber-reinforced PEEK (CFR-PEEK) were implanted through both cortices of the goat mandible. Selected rods of all material types were microtextured using crystallization induced microphase separation, a method for the formation of continuous, open-cell microporous surfaces in thermoplastic polymers. Microtextured and smooth rods were phosphonylated, and calcium was subsequently introduced to the phosphonylated surface by incubating the samples in a saturated solution of calcium oxide. For all substrate materials tested, phosphonylation and calcium posttreatment resulted in an increased propensity for bone binding and apposition, as measured by push out test. Microtextured PP, PE, and CFR-PEEK surfaces that were further phosphonylated and calcium treated resulted in test samples with an increased interfacial strength.

Animals↗

A Windows-based tool for the study of clinical decision-making.

Studies of health-provider decision-making, and of their practice patterns, play a central role in efforts to improve the quality and effectiveness of care and in decreasing costs of healthcare delivery systems. Researchers from a variety of disciplines have studied a broad range of clinical conditions, using a number of methodological approaches and measurement tools, including self-report, written clinical vignettes, simulated clinical encounters using actors as patients and analysis of medical records and administrative data. Although these provide information about the outcomes of clinical decisions, they provide little or no information about the process of the decision. Most clinicians agree that the decision process is as important as the outcome, and indeed it is not unusual to have an exemplary process but a poor outcome. Process information is therefore a crucial dimension of care evaluation. In this paper, we describe a new software product that was originally used to measure diagnostic reasoning in the basic medical science of immunology; subsequently adapted to measure key steps in the clinical decision-making process. This Windows-based software is user-friendly, inexpensive, and requires only commonly available hardware for its operation. It is very flexible, permitting the creation of unlimited numbers and types of clinical scenarios, with diagnostic and/or management approaches. Being clinically "real-world," the scenarios are familiar to the user, who is therefore likely to respond in a "real-world" fashion, with the consequent improved accuracy of data. In addition, a wide range of users may be accommodated. The clinical activities of physicians, nurses, pharmacists, and any other clinical providers may be measured and analyzed by the system. Non-clinical providers, such as managers and administrators, could also be assessed. The system has three major modes. In the Authoring Mode, the author creates a menu, which is common to a number of linked scenarios. For example, the menu for physicians might include the History, Physical examination, Laboratory tests, Radiology, Consultations, etc. The actual details of each related clinical case may then be varied. There is virtually unlimited flexibility in the design of the menu and the clinical details, depending on the needs of the author, and the type of information desired. Both diagnostic and management scenarios are easily constructed. The cost for each individual step may be assigned, using any scoring scale desired. Actual dollar costs, or a suitable point score, are equally possible. Once the menu and associated scenarios are generated, the candidate is asked to solve the clinical problem in the User Mode. The candidate obtains information by "mouse-clicking," so it is not necessary to be a computer expert to use the system. Eventually, the candidate is presented with a short vignette outlining the desired solution, which may include the authors comments, sources for further information, etc. In the Data Collection and Analysis Mode, the candidate proceeds to solve the scenario, the software captures and stores each individual information request i.e., each step in the candidates reasoning process. Thus, the reasoning process can be examined, including timing and order and types of information used; this may be done both for individual candidates, and also for groups. A "gold standard" reasoning may be predetermined by the author for comparison purposes. The software has already been used to teach immunology to medical students, and is currently being expanded to train gynecology surgeons in the use of Clinical Practice Guidelines. The software has potential applications in many aspects of the healthcare field. For educators, it could serve in traditional exit examinations for the clinical disciplines, both undergraduate and postgraduate. (abstract truncated)

Computer-Assisted Instruction↗

Risk factors for acute wheezing in infants and children: viruses, passive smoke, and IgE antibodies to inhalant allergens.

OBJECTIVE: To examine the prevalence of viral infection, passive smoke exposure, and IgE antibody to inhaled allergens in infants and children treated for acute wheezing. DESIGN: Case-control study of actively wheezing children who were compared with children without respiratory tract symptoms. SETTING: University of Virginia Pediatric Emergency Room. PATIENTS: Convenience sample of 99 wheezing patients (2 months to 16 years of age) and 57 control patients (6 months to 16 years of age). MEASUREMENTS AND RESULTS: Serum IgE antibody to inhalant allergens, measured by radioallergosorbent test (RAST), was uncommon in wheezing and control patients under age 2. After 2 years of age, the percentage of RAST-positive patients increased markedly and was significantly higher in wheezing patients than controls after age 4 (72%, n = 54, and 30%, n = 40, respectively, P < .001). Total IgE levels and nasal eosinophilia were strongly correlated with a positive RAST after age 2. Viral pathogens, predominantly respiratory syncytial virus, were identified in nasal washes from 70% (n = 20) of wheezing patients younger than 2 years of age compared with 20% of controls (n = 10), P < .05. After age 2, viruses, particularly rhinovirus, were isolated in washes from 31% (n = 70) of wheezing patients, 64% of whom were also RAST-positive. Levels of cotinine, a nicotine metabolite, were elevated (> or = 10 ng/mL) in saliva from a large percentage of smoke-exposed, wheezing patients under 2 (74%, n = 19) compared with those over 2 (14%, n = 51), P < .001. Odds ratios for wheezing were significant for virus (8.2, confidence interval [CI] = 1.3 to 5.0), and cotinine (4.7, CI = 1.0 to 21.3) in children under 2, and IgE antibody by RAST (4.5, CI = 2.0 to 10.2), virus (3.7, CI = 1.3 to 10.6), and the combination of IgE antibody and virus (10.8, CI = 1.9 to 59.0) were significant risk factors after age 2. CONCLUSION: Wheezing children younger than 2 years of age had a high rate of viral infection and a low rate of IgE antibody to inhalant allergens. When these children were exposed to passive smoke, salivary cotinine levels were elevated suggesting heavy exposure. After 2 years of age, sensitization to inhaled allergens became increasingly important and viruses remained a significant risk factor for wheezing. These data support recommendations to reduce tobacco smoke exposure at home, especially for young patients, and to consider sensitization to inhaled allergens and allergen avoidance in wheezing children at an early age, particularly after age 2 years.

Adolescent↗

Biocidal braided sutures.

Once sutures become contaminated it is difficult for local tissue defenses or antibiotics to eliminate the bacteria and prevent infection. Impregnation of sutures with antibiotics before implantation is one way to prevent bacterial seeding of the suture surface. In this study, braided silk and Dacron sutures were impregnated with the antibiotic complex, neomycin palmitate. Using our standard wound model in the mouse, the efficacy of these biocidal sutures was determined in the presence of Staphylococcus aureus, Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa. Implantation of these biocidal sutures into tissue contaminated with 10(7) organisms resulted in substantially decreased numbers of bacteria as compared with that of tissue receiving control sutures. In most cases, the tissue bacterial counts in the presence of biocidal sutures were also considerably lower than that for similarly contaminated tissue without a suture. Consequently, the presence of the neomycin palmitate eliminated the infection-potentiating effect of the suture. The therapeutic benefit of the biocidal sutures was related to the dose of antibiotic complex and was not adversely affected by delaying suture implantation.

Animals↗