Effect of passive heat stress on arterial stiffness in smokers versus non-smokers.

In non-smokers, passive heat stress increases shear stress and vasodilation, decreasing arterial stiffness. Smokers, who reportedly have arterial dysfunction, may have similar improvements in arterial stiffness with passive heat stress. Therefore, we examined the effects of an acute bout of whole-body passive heat stress on arterial stiffness in smokers vs. non-smokers. Thirteen smokers (8.8 ± 5.5 [median = 6] cigarettes per day for > 4 years) and 13 non-smokers matched for age, mass, height, and exercise habits (27 ± 8 years; 78.8 ± 15.4 kg; 177.6 ± 6.7 cm) were passively heated to 1.5 °C core temperature (T C) increase. At baseline and each 0.5 °C T C increase, peripheral (pPWV) and central pulse wave velocity (cPWV) were measured via Doppler ultrasound. No differences existed between smokers and non-smokers for any variables (all p > .05), except cPWV slightly increased from baseline (526.7 ± 81.7 cm · s(-1)) to 1.5 °C ΔT C (579.7 ± 69.8 cm · s(-1); p < 0.005), suggesting heat stress acutely increased central arterial stiffness. pPWV did not change with heating (grand mean: baseline = 691.9 ± 92.9 cm · s(-1); 1.5 °C ΔT C = 691.9 ± 79.5 cm · s(-1); p > 0.05). Changes in cPWV and pPWV during heating correlated (p < 0.05) with baseline PWV in smokers (cPWV: r = -0.59; pPWV: r = -0.62) and non-smokers (cPWV: r = -0.45; pPWV: r = -0.77). Independent of smoking status, baseline stiffness appears to mediate the magnitude of heating-induced changes in arterial stiffness.

Reliability of 24-h void frequency as an index of hydration status when euhydrated and hypohydrated.

BACKGROUND/OBJECTIVES: Void frequency (VF) is significantly correlated to hydration status, but it is unknown whether VF is reliable when an individual is repeatedly euhydrated (EU) or hypohydrated (HY). The purpose of this study was to test the reliability of VF when individuals were EU or HY on multiple occasions. SUBJECTS/METHODS: Fourteen males (age 22±2 years, mass 79.1±12.8 kg) completed three EU trials achieved with 24-h ad libitum fluid intake, and 14 males (age 22±2 years, mass 78.6±10.4 kg) completed three HY trials achieved with 24-h fluid restriction. Twenty-four hour urine was collected and analyzed for specific gravity (USG) and VF. Subjects voided at a 'normal urgency' (rated a '2' on a 0-4 perceptual scale) throughout each 24-h period. RESULTS: Twenty-four hour USG was greater and VF was lower when HY (1.026±0.003 and 5±2, respectively) versus EU (1.014±0.003 and 7±2; both P<0.05). Intra-class correlations for VF between the three trials at each hydration status were deemed acceptable (0.863 and 0.849 for EU and HY, respectively). Within-subject coefficients of variation for VF were 15±9 and 21±14% for the EU and HY trials. CONCLUSIONS: VF is a reliable index of 24-h hydration status when healthy young males are EU or HY and voiding at a consistent 'urgency'.

Marginal fit of direct temporary crowns.

This study compared the effect that shrinkage of four brands of temporary crown and fixed partial denture resins has on the marginal fit of crowns made from them. Under the conditions of this study, crowns made from Coldpac had marginal discrepancies approximately four times larger than those made from Scutan. Crowns made from Snap and Trim had marginal discrepancies approximately two times larger than those made from Scutan.

Dowel pin positioning technique for fixed partial denture working casts.

This simple, accurate technique of positioning dowel pins saves the time and effort of working with cumbersome bobby pins, paper clips, anesthetic needles, and sticky wax. No pins are pushed into the impression material that might cause distortion. The method (1) allows the dental laboratory technician to place the dowel pins free hand after the impression has been poured and (2) does away with many problems associated with prepositioning the dowel and stabilizing it with sticky wax before pouring the impression. With this method, there is nothing to vibrate loose, and there is excellent vision and access for teasing stone into all recesses of the impression with a spatula or brush. The heavy body and sticky characteristic of Mortite ensures that the bankers pins will not be dislodged during vibration of stone, and the dowel pins can be precisely located.