Search PubMed⌕ Search

Biomedical subjects

W Sampson

Publications and source records attributed to W Sampson.

14 recordsLinked to original sources
PubMed2001

The need for educational reform in teaching about alternative therapies.

Advocacy and non-critical assessment are the approaches currently taken by most U.S. medical schools in their courses covering what is commonly called "complementary and alternative medicine" (CAM). CAM therapies are anomalous practices for which claims of efficacy are either unproved or disproved. The author's research indicates that most medical schools do not present CAM material in a form that encourages critiques and analyses of these claims. He presents the reasons for the unwarranted acceptance of CAM. These include the CAM movement's attempt to alter standards of evaluating therapies. A survey of CAM curricula in U.S. medical schools in 1995-1997 showed that of 56 course offerings related to CAM, only four were oriented to criticism. The author's course at Stanford University School of Medicine approaches CAM with the skepticism and critical thinking appropriate for unproven therapies. The author concludes by calling on all medical schools to include in their curricula methods to analyze and assess critically the content validity of CAM claims.

Attitude of Health Personnel↗
PubMed2001

Induced mandibular condylar growth in a sheep model after functional appliance treatment.

This paper reports on changes in mandibular condylar growth in sheep fitted with experimental functional appliances. The paper also addresses the similarities of mandibular condylar growth in sheep and humans. Experimental functional appliances were developed, constructed and applied to four, four-month old, male sheep. Another four sheep served as matched controls. All animals received fluorochrome bone labels during the study and their weight gain also was recorded. Fifteen weeks later, all animals were sacrificed and each temporo-mandibular joint and left metacarpus were removed. Undecalcified mid-sagittal sections of the joint and metacarpus were prepared for fluorescence microscopy. The mandibular condylar growth vector in sheep was found to be in a postero-superior direction. Condylar growth in the control sheep during the experimental period varied from 8.8 to 11.9 mm, with the mean being 10.6 mm, which is quantitatively similar to two years of condylar growth in human adolescents. In the experimental sheep, the condylar growth varied from 8.5 to 13.3 mm, with the mean being 11.4 mm. When metacarpal growth and weight gain were taken into consideration using multivariant analysis, the coefficients for growth in the postero-superior and posterior direction were found to be high, with adjusted r2 as 0.84 and 0.82 respectively. The induced condylar growth was estimated to be largest in the posterior direction (2.30 mm), which is also similar to previous reports in humans. These findings suggest the appropriateness of using sheep as a model for quantitative histological analysis when investigating the mechanisms of functional appliance treatment.

Analysis of Variance↗
PubMed2000

Acetophenone-based linker for solid-phase peptide synthesis.

A new and cost-effective linker for the generation of carboxylic acid end groups on Multipin supports (SynPhase crowns) has been developed. Synthesis of the linker was based on modification of grafted polystyrene (PS) crowns to generate a hydroxyethyl moiety which is acid labile in 10-20% trifluoroacetic acid (TFA) in dichloromethane (DCM). Solid-phase syntheses of model decapeptides using this linker are described.

Acetophenones↗
PubMed2000

Effects of twin-block therapy on protrusive muscle functions.

Protrusive mandibular function, including maximum protrusive force and fatigue time, was investigated in 66 children displaying Class II Division 1 malocclusion. Thirty-two children were treated with the Clark Twin-block appliance and the other 34 children served as untreated controls. The observation period was 6 months. Cross-sectional data based on pretreatment records showed that maximum protrusive force ranged from 18.5 N to 160 N, with a mean of 80.3 +/- 30.7 N. Maximum protrusive force was significantly higher in males than in females (P <.001). The correlation between maximum protrusive force and chronologic age was low (r = 0.20) and did not reach significance. Maximum protrusive force in the group of children with disk displacement was not significantly different from that of the group without disk displacement. Comparison of pretreatment and 6-month records in the untreated control group revealed a significant increase in maximum protrusive force (P <.01) as a result of normal growth, while the measured change in the Twin-block-treated children did not reach significance. Fatiguing the protrusive muscles did not alter mandibular position in the Twin-block group after 6 months of treatment. The present study does not support the lateral pterygoid hypothesis, as there was no evidence of an increase in mandibular protrusive function after treatment with the Twin-block functional appliance.

Adolescent↗
PubMed2000

A prospective study of Twin-block appliance therapy assessed by magnetic resonance imaging.

Forty children displaying Class II Division 1 malocclusion were involved in a prospective magnetic resonance image investigation to evaluate the effects of Twin-block functional appliances on the temporomandibular joints. None of these children had clinical signs or symptoms of temporomandibular disorders. Nineteen children were treated with a Clark Twin-block appliance for 6 months; the other 21 children received no treatment and served as controls. Comparison between control and Clark Twin-block groups suggested that reduction of the condylar axial angle represents a feature of untreated Class II growth patterns, whereas axial angle stability with Clark Twin-block therapy may suggest alteration of condylar growth direction. Condyles that were positioned at the crest of the articular eminence by the Clark Twin-block at the beginning of treatment had reseated back into the glenoid fossa after 6 months. However, 75% of the condyles were more anteriorly positioned in successfully treated Clark Twin-block cases. There was no clear evidence of remodeling of the glenoid fossa at the eminence as a result of Clark Twin-block treatment. The initial prevalence of disk displacements for the combined groups was 7.5% anterior, 5% medial, and 12.5% for lateral disk displacement. Clark Twin-block therapy had neither positive nor negative effects on disk position, and there was no convincing evidence that the disk was recaptured.

Adaptation, Physiological↗
PubMed1997

Molecular characterization of the hdm2-p53 interaction.

A number of viral oncogenes target the tumour suppressor protein p53 and inactivate its function. This is an important step in tumourogenesis. The cellular oncogene hdm2 acts through a similar mechanism. It binds the N terminus of p53, thereby interfering with the ability of p53 transcriptionally to activate genes responsible for growth arrest or apoptosis after genotoxic insults. The disruption of the interaction of the two proteins therefore comprises a promising therapeutic target for treatment of the subset of human cancers in which this pathway is active. In this paper we attempt to characterize the p53-hdm2 interaction biochemically. We analyse the potential of a series of peptide inhibitors, derived from previously described mdm2 binding peptide display phage, to disrupt this interaction in ELISA assays. We conclude that F19, W23 and L26 of p53 are critical contact points for p53 binding to hdm2. Furthermore, we show the potential of the monoclonal antibody 3G5 to interfere with binding of p53 to hdm2 in ELISA assays. Consequently, we define the binding site of 3G5 on hdm2 using overlapping peptides derived from the N terminus of hdm2 and phage display libraries. The result indicates L66, Y67 and E69 on hdm2 as critical binding points for 3G5. In electrophoretic mobility shift assay we demonstrate the formation of hdm2-p53 complexes that can be disrupted in the presence of 3G5 or inhibitory peptides. Finally, we describe the effects of NEM and DTT on the interaction between the two molecules in ELISA assays. All our results are discussed in the light of the recently published crystal structure of the mdm2-p53 complex. A striking correspondence between our findings and the crystal structure is revealed.

Alkylating Agents↗
PubMed1995

Prediction of dental arch development: an assessment of Pont's Index in three human populations.

Pont's Index was established by Pont in 1909 to predict maxillary dental arch width from the sum of the mesiodistal diameters of the four maxillary incisors. The usefulness of Pont's Index is controversial and, as there has been a recent resurgence of interest in its clinical use for establishing dental arch development objectives particularly by nonspecialists, reassessment of the Index in different human populations was considered worthwhile. This study aimed to evaluate Pont's Index in untreated, noncrowded samples of Australian Aborigines (n = 80), Indonesians (N = 60), and white subjects (N = 60). Measurements were obtained directly from plaster casts; they included mesiodistal crown diameters of the four maxillary incisors, as well as intercanine, interpremolar and intermolar maxillary arch widths as specified by Pont. A series of double determinations confirmed the reliability of the method. Considerable individual variability was noted in each population with regard to the difference between observed values and Pont's estimates, ranging from -5.9 mm to +6.2 mm (interpremolar width) and -6.1 mm to +12.7 mm (intermolar width). No person displayed the ideal arch dimensions predicted by the Index, but values were within +/- 1.0 mm for 17.5% of the Indonesian sample, 20.6% of the Aboriginal sample, and 30.8% of the white sample. Dental arch width was generally underestimated by the Index in Indonesians who tended to display relatively small tooth size and large arch width. A more even distribution of estimates was noted in Australian Aborigines and white subjects, with the Aborigines showing large tooth size and broad dental arches, and the white subjects displaying smaller tooth size and narrow arches. Correlation coefficients computed between observed and expected values were low in all three populations studied (range r = 0.01 to r = 0.56). Although the concept of a simple index with predictive ability is very appealing to some clinicians, the results of this study have highlighted the marked variation in values of Pont's Index for persons with apparently good occlusions, representing three different human populations. Tooth size variation was poorly correlated with arch width variation, with persons often being over or under Pont's estimation due to variation in tooth dimension, particularly in the size of the maxillary lateral incisor. It is concluded that Pont's Index is unlikely to be a useful clinical predictor of dental arch width and the index should not be used as a guide to dental arch development in contemporary populations.

Adolescent↗
PubMed1985

Calcified capsule following augmentation mammaplasty.

Five patients who developed calcification of the capsule following augmentation mammaplasty are described. This long-term complication may be encountered with increasing frequency and should be considered in evaluating women with solid, firm, constructed capsules.

Adult↗