Browsing by keyword "*Prostheses and Implants"
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Effects of poly(2-hydroxyethyl methacrylate) and poly(vinyl-pyrrolidone) hydrogel implants on myopic and normal chick scleraThere has been generally little attention paid to the utilization of biomaterials as an anti-myopia treatment. The purpose of this study was to investigate whether polymeric hydrogels, either implanted or injected adjacent to the outer scleral surface, slow ocular elongation. White Leghorn (Gallus gallus domesticus) chicks were used at 2 weeks of age. Chicks had either (1) a strip of poly(2-hydroxyethyl methacrylate) (pHEMA) implanted monocularly against the outer sclera at the posterior pole, or (2) an in situ polymerizing gel [main ingredient: poly(vinyl-pyrrolidone) (PVP)] injected monocularly at the same location. Some of the eyes injected with the polymer were fitted with a diffuser or a -10D lens. In each experiment, ocular lengths were measured at regular intervals by high frequency A-scan ultrasonography, and chicks were sacrificed for histology at staged intervals. No in vivo signs of either orbital or ocular inflammation were observed. The pHEMA implant significantly increased scleral thickness by the third week, and the implant became encapsulated with fibrous tissue. The PVP-injected eyes left otherwise untreated, showed a significant increase in scleral thickness, due to increased chondrocyte proliferation and extracellular matrix deposition. However, there was no effect of the PVP injection on ocular elongation. In eyes wearing optical devices, there was no effect on either scleral thickness or ocular elongation. These results represent "proof of principle" that scleral growth can be manipulated without adverse inflammatory responses. However, since neither approach slowed ocular elongation, additional factors must influence scleral surface area expansion in the avian eye.
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Modern moulage: evaluating the use of 3-dimensional prosthetic mimics in a dermatology teaching program for second-year medical studentsOBJECTIVES: To evaluate the effectiveness of a teaching method that uses 3-dimensional (3D) silicone-based prosthetic mimics of common serious lesions and eruptions and to compare learning outcomes with those achieved through the conventional method of lectures with 2-dimensional (2D) images. DESIGN: Prospective and comparative. SETTING: University of Massachusetts Medical School. PARTICIPANTS: Ninety second-year medical students. INTERVENTION: A 1-hour teaching intervention using a lecture with 2D images (2D group) or using 3D prosthetic mimics of lesions and eruptions (3D group). MAIN OUTCOME MEASURES: Mean scores in the domains of morphology, lesion and rash recognition, lesion and rash management, and overall performance assessed at baseline, immediately after, and 3 months after each group's respective teaching intervention. RESULTS: Immediately after the teaching intervention, the 3D group had significantly higher mean percentage scores than did the 2D group for overall performance (71 vs 65, P = .03), lesion recognition (65 vs 56, P = .02), and rash management (80 vs 67, P = .01). Three months later, the 3D group still had significantly higher mean percentage scores than did the 2D group for lesion recognition (47 vs 40, P = .03). The 3D group better recognized lesions at 3 months compared with at baseline, whereas the 2D group was no better at recognizing lesions at 3 months compared with at baseline. CONCLUSIONS: Despite limited curricular time, the novel teaching method using 3D prosthetic mimics of lesions and eruptions improves immediate and long-term learning outcomes, in particular, lesion recognition. It is also a preferred teaching format among second-year medical students.
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Prediction of successful voiding immediately after outpatient mid-urethral slingWe set out to identify predictors of successful voiding immediately after outpatient mid-urethral sling. The charts of 126 patients who underwent an outpatient mid-urethral sling procedure were identified. Using discharge without a urinary catheter as the dependent variable, logistic regression analysis modeled the relationship of independent variables including demographic, preoperative urodynamic, and perioperative variables. Sixty-one percent of the patients passed their immediate postoperative voiding trial. Logistic regression analysis revealed that parity > or = 3, Valsalva leak point pressure > 60 cm H(2)O, and high preoperative anxiety remained independently associated with successful voiding. Identifying preoperative variables that are associated with successful voiding after mid-urethral sling may be useful in helping to accurately shape patient expectations and identify those most likely to benefit from preoperative teaching of self-catheterization.