Fibrous dysplasia of the maxilla: a case report together with its conventional imaging and dynamic magnetic resonance imaging findings

We previously reported that dynamic contrast-enhanced MRI parameters and time–signal intensity curves (TICs; also known as contrast index curves) are useful for the differential diagnosis of jawbone lesions. In particular, odontogenic fibroma and ossifying fibroma, which possess similar histopathological features (i.e., a mixture of hard and soft tissue components), display unique TIC patterns, and we consider that the TIC patterns of these lesions reflect their hard and soft tissue components. Therefore, fibrous dysplasia, which contains fibrous tissue and immature isolated trabeculae composed of woven bone, is expected to display an interesting TIC. The purpose of this study was to assess the utility of TICs for differentiating between the abovementioned lesions, which have similar histopathological components.     

Influence of Strain Gradient on Fatigue Life of Carbon Steel for Pressure Vessels in Low-Cycle and High-Cycle Fatigue Regimes

This paper discusses how the strain gradient influences the fatigue life of carbon steel in the low-cycle and high-cycle fatigue regimes. To obtain fatigue data under different strain distributions, cyclic alternating bending tests using specimens with different thicknesses and cyclic tension–compression tests were conducted on carbon steel for pressure vessels (SPV235). The crack initiation life and total failure life were evaluated via the strain-based approach. The experimental results showed that the crack initiation life became short with decreasing strain gradient from 10² to 10⁶ cycles in fatigue life. On the other hand, the influence of the strain gradient on the total failure life was different from that on the crack initiation life: although the total failure life of the specimen subjected to cyclic tension–compression was also the shortest, the strain gradient did not affect the total failure life of the specimen subjected to cyclic bending from 10² to 10⁶ cycles in fatigue life. This was because the crack propagation life became longer in a thicker specimen. Hence, these experimental results implied that the fatigue crack initiation life could be characterized by not only strain but also the strain gradient in the low-cycle and high-cycle fatigue regimes.     

Vascular endoscopic and macroscopic observations after crush stenting of coronary artery bifurcations in pigs.

The crush stent technique has recently been proposed to limit the development of restenosis between drug-eluting stents implanted at coronary artery bifurcations. We studied the stent expansion, apposition to the vessel, and aspect of the overlapping stents after in vivo crush stent implantation. Crush stent implantation was performed at coronary bifurcations in anesthetized swines. The treated sites were examined using intravascular ultrasound and a vascular endoscope. The stents removed from the vessel were analyzed macroscopically. After final kissing balloon inflation, an adequate apposition of the stent to the vessel wall was confirmed by vascular endoscopy and visual inspection. However, the side-branch stent was narrowed at the site of stent overlap, and the overlapping stents in the main branch created a metal mass, which could promote the development of thrombosis. The technique of crush stent implantation with additional kissing balloon inflation is feasible and promising. However, it may be limited by thrombosis and restenosis at the carina because of stent overlapping and potential incomplete apposition. Additional studies are needed to confirm the safety and long-term clinical results of this technique.     

Influence of an experimental palatal plate on thermal perception

PurposeThis study aimed to examine how coverage of the hard palate by an experimental palatal plate influenced thermosensation.MethodsA total of 20 young adult volunteers were recruited from Osaka University Graduate School of Dentistry. An experimental palatal plate, 1.5 mm in thickness, was made for each subject from acrylic resin. The stimulus water were either warmed to 40, 42, 44, 46, or 48 °C or cooled to 30, 26, 22, 18, or 14 °C in a constant-temperature water bath, and the control water were maintained at 37 °C. Subjects were instructed to retain the control water in their mouths for 5 s, then to spit it out and to repeat with the stimulus water. They then rated the intensity of stimulation of warmth or cold compared to the control water by the magnitude estimation method. Each stimulus was administered three times in random order. Two experimental conditions were set: with and without the experimental palatal plate.ResultsPerceived thermal intensity was measured as the slope of the regression line for each condition (with or without the experimental palatal plate, cold or warmth). There was a significant difference between with and without the experimental palatal plate; the regression slope with the plate was shallower than that without the plate (warmth perception with plate = 0.55 ± 0.21 vs. warmth perception without plate = 0.70 ± 0.23, P < 0.05; cold perception with plate = –0.33 ± 0.14 vs. cold perception without plate = –0.39 ± 0.11, P < 0.05).ConclusionThe findings suggested that a denture covering the hard palate obstructs thermal perception.     

Differential responses of HSPs to heat stress in slow and fast regions of rat gastrocnemius muscle

In a recent study, we showed that the rat slow soleus and fast plantaris muscles exhibited different time courses for the response of specific heat shock proteins (HSPs) after 1 h of heat stress. We hypothesized that these differential responses were related, in part, to the varying fiber type composition of these muscles. To further test this hypothesis, we now have determined the responses of Hsp60, Hsp72, and Hsc73 during the 60 h following exposure to a single bout of heat stress in the deep (relatively high percentage of slow fibers) and superficial regions (only fast fibers) of the adult rat gastrocnemius muscle. The temperature of the musculature in the left hindlimb was elevated to approximately 42 degrees C for 1 h, while the right hindlimb served as a control. Two hours after the heat stress, the Hsp60 levels were increased by 1.3- and 2.0-fold in the deep and superficial regions, respectively. The Hsp72 levels were increased (1.8-fold) in the deep region at 8 h after heat stress, whereas in the superficial region these levels were increased between 4 and 48 h (peak at 36 h by 10-fold) after the heat stress. No changes were observed for Hsc73 in either region of the muscle. Combined with our previous data, the results indicate that the responses of HSPs in the rat hindlimb muscles after a single exposure to heat stress are related to fiber type composition of the muscle or muscle region or to the inherent properties of each HSP. From a clinical viewpoint, these data indicate that specific regions (most likely based on fiber type composition) within a muscle may be affected differentially by any intervention inducing HSPs.