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Biomedical subjects

H J Refior

Publications and source records attributed to H J Refior.

184 records · Page 11Linked to original sources

Prevalence of cyclic changes in limb volume (volumotion) of male patients with knee injury and the effects of ischemia/reperfusion due to tourniquet.

During surgery of limbs tourniquet up to a maximum of 2 h is frequently applied which may cause ischemia/reperfusion injury (IRI). During this condition the presence of vasomotion may have consequences for the perfusion and nutritive state of the tissues. We used a noninvasive plethysmographic method to investigate periodic changes in limb circumference (volumotion) in healthy male patients (n = 24) undergoing surgery for knee injury. To facilitate surgery a tourniquet was applied to the thigh, which caused an IRI of the leg. Results are given as mean of all values +/- SEM. Immediately after tourniquet release (duration 57.75 +/- 5.19 min) blood lactate levels in the femoral vein increased significantly from 1.40 +/- 0.08 to 2.59 +/- 0.20 mmol/l (p < 0.001) and pH fell from 7.39 +/- 0.01 to 7.32 +/- 0.01 (p < 0.001). Preoperatively 10 out of 24 patients (42%) showed signs of volumotion on the injured leg with a periodicity ranging from 0.8 to 6.9 cycles/min, whereas none showed volumotion in the control leg (p < 0.001). In the second measurement, taken after surgery and reperfusion while peripheral sympathetic nerves were blocked, 7 out of 18 patients (39%) showed volumotion on the injured leg and 0 on the control leg (p < 0.004). 6 h after IRI, volumotion was observed in 11 out of 17 patients (65%) on the injured leg and in 1 patient (6%) on the control leg (p < 0.001). The mean volume change in the patients with volumotion on the injured leg was 0.057 +/- 0.007 ml/100 ml tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Effect of surface energy on wear characteristics of material combinations for the artificial hip joint].

One of the factors determining the wear of UHMWPE used as acetabular cup material is the lubricating properties of the head materials. In order to determine the lubricating properties, the wettability of Al2O3, ZrO2, CoCrMo and N-coated TiAl6V4 was established. Wettability is determined by the surface energy of the head material (solid-state material), which was measured via the contact angle of drops of fluid. As head material, appropriate rings from the Ring-on-Disc Test as per International Standard 6474 were used. The poorest wettability was associated with CoCrMo. The wettability of Al2O3 and ZrO2 was comparable. Worthy of note is the tendentially good wettability of N-coated TiAl6V4.

Biomechanical Phenomena↗