ABSTRACT
OBJECTIVE: To establish a new animal model of osteonecrosis of the femoral head(ONFH) with improved consistency and incidence of femoral head collapse for studies on the mechanism of osteonecrosis. and on the assessment of treatment effectiveness. METHODS: Twenty adult male emus were used. Guide instrumentation was constructed to position the customized probe just articularly and at the proximal part of the femoral head. An alternating focal liquid nitrogen freezing and radiofrequency heating was applied. At 2, 4, 8, 12 and 16 weeks after surgery, hip magnetic resonance imaging (MRI) was performed. Before the emus were sacrificed, barium sulfate was infused to lower extremities for microangiography. The femoral samples were scanned by micro-computed tomography (Micro-CT) and evaluated histologically. RESULTS: No bird demonstrated signs of infection or died unexpectedly. Hip MRI showed changes massive edema at the 4th week, increasingly localized abnormal signals at the 8th'" week, and femoral head collapse at the 12'h week. Micro-CT scans and histological images at the 16th week showed human-like osteonecrotic changes with impaired local blood supply. Bone mineral density of the collapsed head was (380. 31 + 28. 12) mg/cm3 and trabecular spaces were (0. 86 ±0.32) mm; both were significantly lower than those in the control side, which were (415.75 41.28) mg/cm3 and (1. 17 ± 0. 17) mm, respectively (P < 0. 05). Bone volume fraction of the collapsed head was(47.28 ± 17. 14)% and trabecular thickness was (506. 17 ± 220. 58) p.m; both were significantly higher than those at control side, which were (30. 92 ± 4. 01)% and (325. 50 ±44. 53) pm, respectively (P <0. 05). The microangiography at the 16th week showed that vessel volume fraction was (0. 315 ± 0. 055)% , which was significantly higher than the collapsed side [ (0. 142 ± 0. 059)% ] (P <0. 05). CONCLUSIONS: The emu model of fem-oral head osteonecrosis was successfully established using focal alternating cooling and heating insults. The models, with improved consistency and incidence of femoral head collapse, can be used in studies on the mechanism of osteonecrosis and on the assessment of treatment effectiveness.
Subject(s)
Disease Models, Animal , Femur Head Necrosis/etiology , Freezing/adverse effects , Heating/adverse effects , Animals , Dromaiidae , MaleABSTRACT
Alternating trilinear decomposition (ATLD) algorithm is a promising method for second-order calibration, which is based on an alternating least-squares principle to overcome some shortcomings of the traditional parallel factor analysis (PARAFAC) algorithms, such as the sensitivity to the estimated component numbers and slow convergence. It utilizes an iterative procedure involving Moore-Penrose generalized inverse computations based on singular value decomposition and can be applied to the simultaneous determination of several organic components even in the presence of unknown interfering components. The overlapped chromatogram and spectra system of dihydroxybenzenes were resolved by ATLD combined with reversed-phase high performance liquid chromatography (RP-HPLC)/ diode array detection (DAD). The elution time was set from 1.086 min to 1.399 min with an interval of 1/150 min and the ultraviolet wavelength from 268 nm to 298 nm with an interval of 1 nm. The resolved results were in agreement with the actual results excellently. Catechol (CAT), resorcinol (RES) and hydroquinone (HYD) in aqueous solution were determined simultaneously, whose recoveries were (100.1 +/- 1.0)%, (99.4 +/- 1.4)% and (100.5 +/- 1.7)%, respectively. The results showed this experiment can be easily performed without resorting to time-consuming and complicated procedures and quantified accurately. It successfully solved the resolving problem caused by chromatogram and spectra overlapping in the presence of interfering components. It also revealed the ATLD algorithm can be efficiently applied to solve the second-order calibration problem in HPLC-DAD.
