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Biomedical subjects

J O Rogers

Publications and source records attributed to J O Rogers.

10 recordsLinked to original sources

A comparison between videotaped and live demonstrations, for the teaching of removable partial denture procedures.

AIM: This study was devised to test the effectiveness of videotaped demonstrations as opposed to live demonstrations, to small groups of undergraduate dental students. The outcome was assessed by comparing the students' understanding of the clinical and laboratory technical stages of the altered cast impression technique, which is used in the construction of removable partial dentures. METHOD: 31 students watched a series of videotaped demonstrations and 30 received a similar series of live demonstrations. The altered cast procedure was divided into 5 distinct stages, each of which was assessed with the aid of agreed criteria, initially by the students and then by 2 staff assessors and these results were compared. The students were subsequently asked to rate how helpful the videotaped or live demonstration had been on a 5-point scale. RESULTS: The live demonstration group showed better agreement between the students' assessment and the assessors' assessment of the quality of the work for the first part of the clinical stage. There was no difference in the groups' assessment of the final outcome of this clinical stage and the subsequent laboratory technical stages. Students who observed the live demonstrations indicated higher scores for its helpfulness in performance of all the stages of the technique, when compared to those who had observed a videotaped demonstration. CONCLUSION: Both teaching methods developed a similar level of understanding of the principles behind the exercise, although the students preferred the live demonstrations. A carefully produced videotaped demonstration can be a useful alternative to a live demonstration in teaching the short and clear cut technique selected for this study.

Chromium Alloys↗

The effect of hydrocortisone and thyroxine on development of calcium homeostasis in embryonic intestinal epithelium.

Cytoplasmic Ca2+ concentration of epithelial cells from 14-day embryonic chick duodena decreased during 72 h of organ culture to a value 54% of that found at 17 days in vivo. The ability of cells to maintain a constant Ca2+ concentration when challenged with high extracellular calcium was also significantly reduced. Addition of 1 microM hydrocortisone during culture restored both parameters of Ca2+ homeostasis to that of 16-day uncultured duodena, and rise in cytoplasmic Ca2+ was significant within 4 h of hormone treatment. Thyroxine influenced epithelial Ca2+ similarly, but to a lesser degree and only after 48-72 h of culture. These data indicate that glucocorticoids, and possibly thyroid hormones, influence the development of calcium homeostasis in intestinal epithelium.

Animals↗

Diagnosis and management of the dry mouth: Part 1.

Dry mouth is a relatively common problem, often neglected by patients and dentists alike. This article reviews the symptoms, causes and treatment of xerostomia and provides guidelines for recognizing the condition at an early stage.

Adult↗

Implant supported fixed distal extension prostheses.

The distal extension fixed implant supported prosthesis is now available as an alternative to a partial denture. However, not all patients will be suitable for such treatment. Limitations imposed on fixture length, the effect of gape upon instrumentation, the size of abutment components and the design of the superstructure are discussed in this article, to assist the general practitioner in case referral.

Contraindications↗

Development of Ca2+ homeostasis in epithelial cells from embryonic and neonatal intestine.

The fluorescent probe fura-2 was used to assay Ca2+ levels in epithelial cell suspensions from embryonic and neonatal chick duodenum. Cell preparations maintained high viability, completely hydrolyzed fura-2/AM to fura-2, retained 92% of cellular fura-2 within the cytoplasmic compartment, and gave low autofluorescence values during assay. Fura-2 leakage from loaded cells occurred at all ages, but could be corrected for in subsequent calculations of cellular Ca2+. Cytoplasmic Ca2+ concentration was 76-80 nM in cells from 14- to 16-day embryonic intestine, rose significantly to 92-98 nM at 17-20 days, and reached 209 nM at 1-day post-hatch when assayed in buffers containing 1.3 mM Ca2+. The developmental rise in cytoplasmic Ca2+ was accompanied by an enhanced ability of cells to maintain a constant Ca2+ concentration at increased levels of extracellular Ca2+ and by a highly correlated rise in alkaline phosphatase (ALP) activity. Epithelial Ca2+ subsequently decreased to the "adult" value of 133-142 nM and was constant along the crypt-villus axis of neonatal intestine. These results verify that fura-2 can be used to compare baseline cytoplasmic Ca2+ values of epithelial cells from developing intestine, reveal that significant changes in Ca2+ homeostasis occur during ontogeny, and suggest that epithelial Ca2+ may modulate ALP activity during the differentiation of embryonic enterocytes.

Alkaline Phosphatase↗

Preparation of microvillus membrane vesicles from the intestine of embryonic and young chicks.

1. A procedure is described for the isolation of microvillus membranes from 19-day old embryonic, newly hatched, and 2-day old chicken intestine. 2. The magnesium concentration of epithelial cell homogenates is shown to be a crucial factor in obtaining membranes of equal purity from the three age groups. 3. Microvillus membranes are purified 20-25 fold over the original homogenate and form vesicles which are tightly sealed based on the Na+-dependent accumulation of glucose to levels four to five times equilibrium values. 4. These membrane preparations should prove useful in future studies concerning the embryonic and neonatal development of microvillus enzymes and nutrient transport systems in the chicken.

Animals↗

Implant-stabilized complete mandibular denture for a patient with cerebral palsy.

Sufferers of cerebral palsy often have difficulty in chewing, speaking and swallowing because of the involuntary muscle spasms caused by their condition. This problem also makes it very difficult or even impossible for them to wear complete mandibular dentures. This article describes a cerebral palsy sufferer who was successfully fitted with a complete lower denture stabilized by osseointegrated implants. It may be possible to apply the techniques used for people with similar problems.

Cerebral Palsy↗

The extent of maintenance required by implant-retained mandibular overdentures: a 3-year report.

Astra Tech implants were used to support implant-retained mandibular overdentures for 25 edentulous patients (12 with magnet retention and 13 with stud retention). The patients were followed for 3 years, and a detailed record was kept of the extent of maintenance required after placement of the dentures. There were 64 episodes of maintenance related to the overdentures in the magnet retention group and 63 episodes of maintenance in the stud retention group. Episodic maintenance was greatest during the first year, with the magnet group having 30 episodes and the stud group 34. The number of visits required for maintenance related to both the maxillary and mandibular dentures was 117 for the magnet retention group and 86 for the stud retention group. There was no statistically significant difference in the amount of postplacement care between the two groups.

Adult↗