Sonic hedgehog signalling inhibits palatogenesis and arrests tooth development in a mouse model of the nevoid basal cell carcinoma syndrome.

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant or spontaneous disorder characterized by multiple cutaneous basal cell carcinomas, odontogenic keratocysts, skeletal anomalies and facial dysmorphology, including cleft lip and palate. Causative mutations for NBCCS occur in the PTCH1 gene on chromosome 9q22.3-q31, which encodes the principle receptor for the Hedgehog signalling pathway. We have investigated the molecular basis of craniofacial defects seen in NBCCS using a transgenic mouse model expressing Shh in basal epithelium under a Keratin-14 promoter. These mice have an absence of flat bones within the skull vault, hypertelorism, open-bite malocclusion, cleft palate and arrested tooth development. Significantly, increased Hedgehog signal transduction in these mice can influence cell fate within the craniofacial region. In medial edge epithelium of the palate, Shh activity prevents apoptosis and subsequent palatal shelf fusion. In contrast, high levels of Shh in odontogenic epithelium arrests tooth development at the bud stage, secondary to a lack of cell proliferation in this region. These findings illustrate the importance of appropriately regulated Hedgehog signalling during early craniofacial development and demonstrate that oro-facial clefting and hypodontia seen in NBCCS can occur as a direct consequence of increased Shh signal activity within embryonic epithelial tissues.

The effect of different exposure routines on the surface microhardness of a light-activated resin composite.

OBJECTIVES: To compare the surface microhardness of a resin composite following exposure to a pulse-delayed activation routine and a standard continuous routine using a quartz-halogen lamp. Additionally, to assess the effect of increasing the distance between the activator light and the specimen using a continuous exposure routine. METHOD AND MATERIALS: Disk specimens of a commercial resin composite restorative material were exposed to a quartz-halogen lamp in a three-step pulse-delayed routine. A continuous exposure was used as a control. Surface microhardness was recorded at the end of each step and at 1 hour after initial exposure. The data yielded four groups and the control (n = 15). Further specimens were exposed to the activator light held at a predetermined distance from the specimen. RESULTS: The pulse-delayed routine yielded a progressive and significant increase in mean microhardness at the end of each step, and the maximum mean value was significantly lower than the control. The effect of increasing the exposure distance yielded a significant decrease in mean hardness number with increasing distance for the distances selected. Regression analysis indicated a positive linear relationship between microhardness and the natural logarithm of time and a negative correlation between microhardness and distance, respectively. CONCLUSION: The modified activation routines investigated resulted in significantly reduced surface microhardness numbers compared with the controls.

Callers' ability to understand advice received from a telephone health-line service: comparison of self-reported and registered data.

OBJECTIVE: To validate users' perception of nurses' recommendations to look for another health resource among clients seeking teleadvice. To analyze the effects of different users' and call characteristics on the incorrectness of the self-report. DATA SOURCES/STUDY SETTING: This study is a secondary analysis of data obtained from 4,696 randomly selected participants in a survey conducted in 1997 among users of Info-Santé CLSC, a no-charge telenursing health-line service (THLS) available all over the province of Québec. STUDY DESIGN/DATA COLLECTION: Self-reported advice from follow-up survey phone interviews, conducted within 48 to 120 hours after the participant's call were compared to the data consigned by the nurse in the computerized call record. Covariables concerned characteristics of callers, context of the calls, and satisfaction about the nurses' intervention. Association between these variables and inaccurate reports was identified using multinomial logistic regression analyses. PRINCIPAL FINDINGS: Advice to consult were recorded by the nurse in 42 percent of cases, whereas 39 percent of callers stated they had received one. Overall disagreement between the two sources is 27 percent (12 percent by false positive and 15 percent by false negative) and kappa is 0.45. Characteristics such as living alone (adjusted OR = 2.5), calls relating to psychological problems (OR = 2.8), perceived seriousness (OR = approximately 2.6), as well as others, were associated with inaccurate reports. CONCLUSIONS: Telephone health-line providers should be aware that many callers appear to interpret advice to seek additional health care differently than intended. Our findings suggest the need for continuing quality control interventions to reduce miscommunication, insure better understanding of advice by callers, and contribute to more effective service.

[Recommendations for appeal to another resource in a health case brought by nurses in the Info-Health Service CLSC: convergence between utilization declarations and informants' data]. / Recommandations de recours à une autre ressource en santé faites par les infirmières du service Info-Santé CLSC: convergence entre les déclarations des utilisateurs et les données informatisées.

OBJECTIVES: To examine the perception of telephone advice-line users as to whether or not a formal recommendation had been made to seek another consultation and to compare users' perception to what the nurse documented. To analyze the effects of different users' and call characteristics on the incorrectness of the self-report. DATA SOURCES/STUDY SETTING: This study is a secondary analysis of data obtained from 4,696 randomly selected participants in a survey conducted among users of Info-Santé CLSC, a free-of-charge telenursing health-line service (THLS) available throughout the province of Quebec. STUDY DESIGN/DATA COLLECTION: Self-reported advice from follow-up survey phone interviews, conducted within 48-120 hours after the participant's call, were compared to the data consigned by the nurse in the computerized call-record. Covariables concerned characteristics of callers, context of the call, and satisfaction with the nurses' intervention. Association between these variables and inaccurate reports was identified using multinomial logistic regression analyses. PRINCIPAL FINDINGS: Advice to consult another health resource was recorded by the nurse in 42% of cases, whereas 39% of callers stated they had received such a recommendation. Overall disagreement between the two sources is 27% (12% by false positive and 15% by false negative) and kappa is 0.45. Characteristics such as living alone (adjusted OR = 2.5), calls relating to psychological problems (OR = 2.8), perceived seriousness (OR = -2.6) as well as others, were associated with inaccurate reports. CONCLUSIONS: Telephone health-line providers should be aware that many callers appear to interpret advice to seek additional health care differently than intended. Our findings suggest the need for continuing quality control interventions to reduce miscommunication, ensure better understanding of advice by callers, and contribute to more effective service.