No abstract

Ultrasonometry seems to have a future for the evaluation of fracture healing. Ultrasound propagation velocity (USPV) significantly decreases at the same time that bone diameter decreases as healing takes place, thus approaching normal values. In this investigation, both USPV and broadband ultrasound attenuation (BUA) were measured using a model of a transverse mid-diaphyseal osteotomy of sheep tibiae. Twenty-one sheep were operated and divided into three groups of seven, according to the follow-up period of 30, 60, and 90 days, respectively. The progress of healing of the osteotomy was checked with monthly conventional radiographs. The animals were killed at the end of the period of observation of each group, both operated-upon and intact tibiae being resected and submitted to the measurement of underwater transverse and direct contact transverse and longitudinal USPV and BUA at the osteotomy site. The intact left tibia of the 21 animals was used for control, being examined on a symmetrical diaphyseal segment. USPV increased while BUA decreased with the progression of healing, with significant differences between the operated and untouched tibiae and between the periods of observation, for most of the comparisons. There was a strong negative correlation between USPV and BUA. Both USPV and BUA directly reflect and can help predict the healing of fractures, but USPV alone can be used as a fundamental parameter. Ultrasonometry may be of use in clinical application to humans provided adequate adaptations can be developed. ß

No abstract

The methodology developed in the present work provides appropriate storage conditions during irradiation of both red blood cells and platelet blood components using a teletherapy unit.

The results showed that a dose of 2500 cGy completely inactivates T cells in RBC units irradiated with cobalt-60 source.

The method used to store the blood bags during irradiation guaranteed that all damage caused to the cells was exclusively due to the action of radiation at the doses applied. It was demonstrated that prolonged storage of 60Co-irradiated RBCs results in loss of membrane phospholipids asymmetry, exposing phosphatidylserine (PS) on the cells' surface with a time and dose dependence, which can reduce the in vivo recovery of these cells. A time- and dose-dependence effect on the extracellular K+ and plasma-free Hb levels was also observed. The magnitude of all these effects, however, seems not to be clinically important and can support the storage of irradiated RBC units for at last 28 days.

Articles you may be interested inPhotoacoustic signal normalization method and its application to the measurement of the thermal diffusivity for optically opaque materials Rev. Sci. Instrum. 77, 064902 (2006); 10.1063/1.2209951 Determination of thermophysical parameters of porous silicon using a photothermal technique Rev. Sci. Instrum. 74, 848 (2003); 10.1063/1.1526151 Thermal diffusivity of composites determined by photoacoustic piezoelectric technique Rev. Sci. Instrum. 74, 834 (2003); 10.1063/1.1520310 Thermal diffusivity measurements in the photoacoustic open-cell configuration using simple signal normalization techniques A new method for the determination of thermal conductivity and thermal diffusivity from linear heat source measurements Rev.

Objectives: The objective of this study was to compare the in vitro ultrasonic velocity and attenuation in bone healing evaluation. Methods: Seventeen sheep weighting 37 kg in average were used, being divided into two groups of five animals each and one group of seven animals, according to the postoperative follow-up time (30, 60 and 90 days, respectively). Osteotomies were performed on the right tibiae and the intact left tibiae of the 17 animals were used as control. The healing process was monitored with conventional conventional radiographs taken at two-week intervals. The animals were sacrificed at the end of the corresponding follow-up period and both right and left tibiae were removed for in vitro underwater and contact ultrasound evaluations. The transverse and longitudinal ultrasound propagation velocity (USPV) and the broadband ultrasound attenuation (BUA) were measured and correlated. Results: USPV increased with the progression of the healing process, while BUA decreased, with significant differences between the experimental and control groups and between the experimental groups, for most of the comparisons. Conclusion: It was concluded that the method using ultrasound as employed in this investigation is feasible and reliable for evaluating cortical bone healing.