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Biomedical subjects

D F Williams

Publications and source records attributed to D F Williams.

208 records · Page 12Linked to original sources
PubMedDate not supplied

Effects of speech and language disorders on raters' perceptions.

Using semantic differential scales with nine trait pairs, 465 students at two universities rated five descriptions, one portraying an individual without a disorder and four depicting communicative disorders. Statistical analyses indicated that the descriptions with no disorder and with a language disorder were rated significantly lower in ambition than those depicting stuttering, voice, or articulation disorders. Other differences emerged when the raters were divided by geographical location and age. Location was a significant factor in the responses for the traits of social adjustment, employability, and ambition. Age of respondent correlated significantly with ratings of tension and employability.

Adolescent↗
PubMedDate not supplied

Binding of (3H)7 alpha,17 alpha-dimethyl-19-nortestosterone (mibolerone) to progesterone receptors: comparison with binding of (3H)R5020 and (3H)ORG2058.

The binding characteristics of (3H)7 alpha,17 alpha-dimethyl-19-nortestosterone [3H)DMNT) to progesterone receptors (PgR) of calf uterine tissue cytosol were determined and compared to those of the synthetic progestins (3H)ORG2058 and (3H)R5020. Scatchard plot analysis of the equilibrium binding data showed that (3H)DMNT binds to calf uterine PgR with a KD of 2.35 +/- 1.1 nM. This value is slightly higher than that of (3H)R5020 (KD = 1.16 +/- 0.4 nM) and (3H)ORG2058 (KD = 1.04 +/- 0.65 nM). Analysis of dissociation kinetics showed that (3H)DMNT dissociates much more rapidly from the receptor than the other two ligands. Competition experiments showed that ORG2058 has a lower inhibition constant (Ki) than DMNT. Sucrose density gradient (SDG) analysis of PgR showed that (3H)ORG2058-PgR complexes sediment as 8S, (3H)R5020-PgR complexes sediment as 8S and 4S, and (3H)DMNT-PgR complexes sediment as 8S entities along with dissociated (3H)steroid. These data suggest that (3H)DMNT binds to PgR with lower affinity than (3H)ORG2058 and (3H)R5020. The number of binding sites detected with (3H)DMNT are significantly lower than those measured with (3H)ORG2058.

Animals↗
PubMedDate not supplied

Modulation of steroid affinity for the androgen receptor by sucrose.

The effects of sucrose on androgen binding to its receptor were investigated. Sucrose decreased the rate of thermal inactivation of unoccupied and occupied androgen receptor (AR) and the rates of [3H]5 alpha-dihydrotestosterone [( 3H]DHT) dissociation from both activated and nonactivated AR complexes. Binding of [3H]DHT to AR in vivo, or in intact cells at 37 degrees C, caused reduction of [3H]DHT dissociation from cytosolic and nuclear complexes, as compared to in vitro labeled receptor complexes. Further, exposure of these complexes to sucrose at 0 degrees C caused an additional reduction of dissociation rates. Thus, the decrease of [3H]DHT dissociation induced by sucrose is independent of the reaction that reduces DHT dissociation from activated and transformed AR. Sucrose also reduced the ability of mersalyl acid to inactivate AR complexes. This effect of sucrose was markedly diminished in the presence of 2M urea. Sucrose did not significantly affect the association rate, sedimentation properties, or nuclear binding ability of AR complexes, but it did decrease the equilibrium dissociation constant. Other monosaccharides and disaccharides also stabilized AR. These data suggest that sucrose induces conformational changes in the steroid binding domain of androgen receptor, thereby reducing the rates of inactivation, steroid dissociation, and the accessibility of sulfhydryl groups to mersalyl.

Animals↗
PubMedDate not supplied

Perceptions of communicative disorders: verification and specification of rater variables.

UNLABELLED: Using semantic differential scales with nine trait pairs, 600 students at three universities rated five descriptions, one depicting an individual without a disorder and four portraying individuals with communicative disorders. Statistical analyses indicated that the description with no disorder was rated as significantly less ambitious than the described articulation disorder. Other differences emerged when raters were divided by gender and age. Male subjects rated the portrayed individuals as more highly stressed than did females. A significant negative correlation was found for age of respondent and ratings of self-esteem. Results support previous research suggesting that rater gender and age impact perceptions of communicative disorders. LEARNING OUTCOMES: As a result of this activity, the participant will be able to: (1) identify the different means by which investigators have studied the stereotyping of people with communicative disorders, (2) discuss how listeners perceive those with and without communicative disorders, and (3) identify listener traits that may be associated with negative perceptions of people with communicative disorders.

Adolescent↗
PubMedDate not supplied

The clinical wear of three posterior composites.

The wear of three posterior composites and two amalgams was assessed clinically and measured on replica models. For the composite restorations abrasion was measured as the depth of enamel exposed at the cavity margin. Attrition was measured for all materials as the depth of surface wear determined by laser interfereometry. For the posterior composites the mean abrasion was: Clearfil 79.2 microns, Occlusin 175.9 microns and P-30 96.1 microns. The corresponding values for attrition were: 153.4 microns, 205.9 microns and 255.5 microns, respectively. The attrition of the two amalgams was: New True Dentalloy 120.8 microns, Solila Nova 115.3 microns. Therefore, attrition was greater than abrasion and the attrition of the three composites was greater than that of the two amalgams. Abrasion was affected by local factors, including the marginal contour of the restoration, whereas attrition was largely a function of the properties of the material itself. These findings indicate that composites should not be considered as a direct alternative to amalgam, especially in patients with high occlusal stress.

Analysis of Variance↗