Surface hardness of light-activated resin composites cured by two different visible-light sources: an in vitro study.

OBJECTIVE: Microhardness values of upper and lower surfaces of disk specimens of 3 commercially available resin composites were compared and cured using both the traditional halogen source and a plasma arc lamp. METHOD AND MATERIALS: Twenty samples of each of the resin composites were cured in nylon washers. Ten samples of each composite were cured using the appropriate halogen lamp protocol, and 10 samples of each were cured using the plasma lamp protocol. Surface microhardness measurements were carried out using a calibrated Vickers indenter on both top and bottom surfaces after 7 days of storage in air at 20 degrees C. Statistical analysis of the data was carried out using a commercial statistical package. The data for top and bottom surfaces were analyzed separately using a repeated measures analysis of variance (ANOVA). RESULTS: Lamp, composite, and the interaction between lamp and composite were significant in determining the results for both top and bottom surfaces of the disk-shaped specimens. The plasma lamp yielded lower hardness values for all surfaces compared with the halogen source, but the size of the difference depended on the composite. CONCLUSION: Caution must be exercised in the plasma irradiation of resin composites as a curing method due to the possibility of reduced surface microhardness values that may reflect a reduced percent conversion of monomer to polymer.     

Experimental comparison of the thrombogenicity of fibrin and PTFE flow surfaces

Two types of 4 mm ID prostheses were studied in the carotid arteries of the dog. These were noncrimped polypropylene-supported filamentous velour knitted Dacron (PPSFV) and expanded polytetrafluoroethylene (e-PTFE, Gore-Tex). Thrombus-"Free" Surface TFS) areas and patency rates were determined at the end of the implant periods. One series of implants was subjected to controlled low flow rates for six hours; another was exposed to physiologic flow rates and observed at seven days, 14 days, and 12 weeks. At six hours the filamentous Dacron, preclotted according to a specific regimen utilizating heparin, performed as well as, and possibly better than, e-PTFE. The Gore-Tex developed surface coagulum in an irregular fashion which was related to graft wetting and blood soakage. Seven-day TFS scores and patency rates of the two graft types were comparable at physiologic flow rates. At two weeks, TFS scores and patency rates of the two graft types were comparable at physiologic flow rates. At two weeks, TFS scores and patency rates dropped. This was sufficiently marked in the case of e-PTFE that longer-term implants were not done. However, PPSFV grafts were implanted for 12 weeks, and all grafts examined at that time had closed. It appears that patency of 4 mm ID grafts of this construction will not be reliably attained in the dog carotid artery without the use of platelet-inhibitory drugs until complete healing has occurred.     

Suppression of canine antral gastrin secretion by urine

Distention of the gastric antrum with an alkaline fluid normally results in the secretion of gastrin. Following gastrocystoplasty in humans, however, hypergastrinemia has not been observed. We explored the possibility that a component of urine may suppress antral gastrin activity in the dog. Partial cystectomy and antral transposition to the bladder (ATB) was performed in five animals and antral transposition to the colon (ATC) was performed in five other dogs to serve as a hypergastrinemic controls. At four and eight weeks after surgery the mean serum gastrin levels in the ATC dogs were significantly greater than the mean preoperative levels (p less than 0.05). In contrast, at four and eight weeks after surgery the mean serum gastrin levels in the ATB animals were significantly less than the mean preoperative levels (p less than 0.05). The antral G-cell density as determined by immunohistochemical study at eight weeks after surgery was greater than normal in the ATC dogs but less than normal in the ATB dogs; but the differences did not achieve statistical significance. In another series of experiments using four other dogs a 4% aqueous peptone solution and a 4% peptone solution in concentrated dog urine were instilled into exteriorized antral pouches. The mean serum gastrin levels at 60 and 90 minutes after instillation of the former were significantly increased (p less than 0.05), but there was little or no change after instillation of the latter. Urine, or a component of urine, appears to suppress canine antral gastrin secretion and may explain the absence of hypergastrinemia following gastrocystoplasty in humans.     

The development and reliability of the Cantonese version of the Allen Cognitive Level Screen

The Allen Cognitive Level Screen is a quick screening test to assess the cognitive functions of people with cognitive impairments or psychiatric disabilities. The purposes of the study were to translate the Allen Cognitive Level Screen into Cantonese and to gather evidence of the reliability of the translated version. Translation was performed by three bilingual occupational therapists. A panel of another five bilingual occupational therapists verified the accuracy of translation. Thirty randomly selected Cantonese‐speaking healthcare workers performed the Cantonese version of the Allen Cognitive Level Screen. Results suggested that the test seemed to be accurately translated. Inter‐rater reliability and the test–retest coefficient of the Cantonese version of the Allen Cognitive Level Screen were 0.98 and 0.73 (test–retest interval = 28.3 days) respectively. Future research should be directed towards further exploring the psychometric properties and clinical application of the Cantonese version of Allen Cognitive Level Screen. Copyright © 2001 Whurr Publishers Ltd.     

Dietitians' Perspectives on Teaching Nutrition to Medical Students

Objectives: The provision of nutrition care by health professionals can facilitate improved patient nutrition behaviors. Some education institutions include nutrition in their medical curriculum; however, doctors and medical students continue to lack competence in providing nutrition care. Dietitians are increasingly teaching nutrition to medical students, yet evidence on the topic remains anecdotal. It is important to understand the experiences of these dietitians to support improvements in undergraduate medical nutrition education. The aim of this study was to explore dietitians' perspectives of teaching nutrition to medical students.

Methods: A qualitative study was conducted in collaboration with the Need for Nutrition Education/Innovation Programme (NNEdPro). Twenty-four dietitians who had provided nutrition education to medical students participated in individual semistructured interviews. Participants were from Australia (n = 5), New Zealand (n = 1), the United States (n = 6), Canada (n = 5), the United Kingdom (n = 5), Germany (n = 1), and Finland (n = 1). Data analysis was conducted using a constant comparative approach to thematic analysis.

Results: The dietitians expressed confidence in their ability to teach medical students and believed that they were the most appropriate professionals to administer the education. However, they were not confident that medical students graduate with sufficient nutrition competence and attributed this to poor curriculum planning for nutrition. Dietitians had access to useful resources and tools to support education, with opportunity to contribute further to integration of nutrition throughout medical curricula.

Conclusion: This study suggests that dietitians are likely appropriate nutrition teachers in medical education. However, optimizing dietitians' role requires their further involvement in curriculum planning and development. Including dietitians as members of medical faculty would facilitate their input on nutrition throughout the curriculum, which could enhance the nutrition education of medical students.     

Peer Reviewed: Can Newly Acquired Healthy Behaviors Persist? An Analysis of Health Behavior Decay

Introduction

We evaluated data from the Coronary Health Improvement Project (CHIP) to determine whether improved health behaviors associated with this intervention persisted or decayed during 18 months of follow-up.

Methods

Participants were 348 volunteers aged 24 to 81 years from the Rockford, Illinois, metropolitan area enrolled in CHIP, a 4-week educational course delivered as lectures. The intervention taught the importance of making better lifestyle choices and improving dietary and physical activity behaviors. Physical activity and dietary behaviors were assessed at baseline, and changes in behaviors were assessed at 6 weeks and 18 months. Changes were evaluated according to quartile groupings of each variable at baseline.

Results

No baseline differences were found between participants who dropped out and participants who provided data through 18 months. Mean changes significantly improved through 6 weeks for each of the 21 selected physical activity and dietary behavior variables except percentage of daily calories from carbohydrates. Mean changes significantly improved through 18 months for each of the 21 variables except calories from protein, alcohol, and whole grain servings. The percentage of participants who improved their physical or dietary behavior at 6 weeks ranged from 49% for percentage of daily calories from carbohydrates (64% at 18 months) to 91% for intake of dietary cholesterol per day (84% at 18 months). The level of change through 18 months for all variables was significantly influenced by quartile groupings at baseline. Physical activity improved significantly through 18 months only for participants in the lowest two quartiles of physical activity at baseline. Exercise decreased significantly through 18 months for participants in the highest quartile of physical activity at baseline.

Conclusion

During an 18-month period, participants'' physical activity and dietary behaviors improved significantly. Even though behavior improvement tended to be greater at 6 weeks, most healthy behaviors did not return to baseline levels after 18 months.