Influence of preimplant surgical intervention and implant placement on bone wound healing

The aims of the present investigation were to study (1). the influence of preimplant (4 weeks) surgical intervention and (2). the influence of the implant placement per se on bone density and mineralized bone-implant contact (BIC) at implant sites in the rabbit jawbone. The experiment was performed in the edentulous area of the maxillas of 16 adult rabbits. In eight rabbits, the alveolar bone on the left side (test) was surgically exposed and a groove was prepared in the bone crest. Trabecular bone and marrow tissue were removed, and a bioabsorbable barrier membrane was placed to cover the groove. The right side underwent no treatment and served as the control. Four weeks later, a screw-shaped titanium implant was placed transversally through the maxilla, penetrating both the test and the control areas. After another 4 weeks of healing, the animals were killed to obtain ground sections for histomorphometry. Untreated jaws from eight rabbits served as reference specimens. In the rabbits subjected to surgery, the areas (mm2) of both mineralized bone and marrow tissue were similar for test and control (4.9 +/- 1.7 vs. 5.1 +/- 2.2 and 6.3 +/- 5.7 vs. 6.8 +/- 5.7 for bone and marrow, respectively). The BIC (%) for all threads was significantly lower on the test side than on the control side (32.1 +/- 27.7 vs. 47.7 +/- 20.3). The bone density (%) of the total experimental area was similar for test and control (48.5 +/- 12.1 vs. 46.5 +/- 9.3), as was the bone density in the area within the implant thread valleys and their mirror areas (43.0 +/- 13.9 vs. 41.3 +/- 13.5, and 40.2 +/- 11.0 vs. 40.3 +/- 7.2 for thread area and mirror area, respectively). The bone density of the total experimental area in the untreated rabbits was 35.9 +/- 5.2%. This value was significantly lower than the values in the total experimental areas (test and control) of the surgically treated rabbits. Similarly, the density of the reference area in the untreated rabbits was 25.4 +/- 5.3%, which was also significantly lower than the bone density of the periimplant area of the surgically treated rabbits. We conclude that the surgical trauma caused by the placement of implants in the maxilla of rabbits significantly enhanced the bone density of the implant sites. Surgical intervention in the implant sites 4 weeks prior to the implant placements, however, did not further enhance bone density or BIC.     

Effects of the inferior alveolar nerve stimulation on tongue muscle activity during mastication in freely behaving rabbits

Genioglossus (Gg) reflexes elicited by electrical stimulation of the inferior alveolar nerve were examined in naturally chewing rabbits. To eliminate possible contaminations of the digastric (Dig) activity in the Gg responses, the Dig nerve was denervated bilaterally. Masticatory and tongue muscles were well coordinated during chewing after the denervation; i.e., there were no significant differences in the phase durations between before and after denervation. The Gg reflex measured was divided into three categories depending on the chewing phase (i.e., jaw-opening, OP; fast-closing, FC; and slow-closing, SC) in which the stimulus was delivered. The reflex amplitude was phasically modulated for the phases, in that the amplitude in the OP phase was larger than that in any other phase (P<0.05). On the other hand, the amplitude in the FC and SC phases was not significantly different to each other and from the control value obtained when the animal was awake and resting. The pattern of the modulation in the reflex amplitude was different from the previous report as to the Dig reflex in that OP相似文献   

骨刺痹痛丸对体外培养软骨细胞增殖的影响

为探讨骨刺痹痛丸含药血清对体外软骨细胞增殖的影响,取4周龄兔膝关节软骨分离、培养出软骨细胞后,接种于6孔和96孔板中,以A组空白兔血清培养,B组骨刺痹痛丸含药血清培养。分别进行细胞形态学、免疫组织化学的观察及以MTT法检测软骨细胞的活性和增殖能力。结果显示骨刺痹痛丸含药血清在第4~10天软骨细胞增殖加速,与同期对照组比较,具有显著统计学意义(P<0.05)。表明骨刺痹痛丸可促进软骨细胞增殖。     

平阳霉素磁性微球治疗海绵状血管瘤的实验研究

目的 :探讨自制的平阳霉素磁性微球 (MPMs)治疗海绵状血管瘤的可行性及机制。方法 :将 2 0只新西兰白兔分为 4组 ,分别将MPMs、平阳霉素及空白微球注入兔耳缘静脉 ,2 1d后处死动物 ,在光镜、透射电镜下观察兔耳静脉的组织学变化。结果 :MPMs、平阳霉素及空白微球对血管壁均有损伤作用 ,以MPMs组引起血管闭锁最为明显。结论 :MPMs可通过平阳霉素的药物作用以及本身的栓塞作用使血管闭锁 ,可作为海绵状血管瘤硬化治疗的一种较理想药物     

Inositol stimulates DNA and protein synthesis, and expansion by rabbit blastocysts in vitro.

The effect of different concentrations (0, 0.6, 3, 15, 75 and 375 microM) of myo-inositol on the development of rabbit morulae to expanded blastocysts was investigated in terms of blastocyst expansion and synthesis of DNA and protein, as measured by incorporation of [3H]thymidine and [14C]amino acids into acid-precipitable material. A concentration of 15 microM inositol caused a 2.8-fold increase in blastocyst expansion (P less than 0.01), a 9.9-fold increase in thymidine incorporation into DNA (P less than 0.01) and a 3.6-fold increase in amino acid incorporation into protein (P less than 0.01). There were no significant differences in the range from 15 to 375 microM inositol.     

Chronic catheterization of the epidural space in rabbits: a model for behavioural and histopathological studies. Examination of meptazinol neurotoxicity

A technique of epidural catheterization in rabbits is described. Twelve albino rabbits received a totally implanted epidural catheter system. The system was implanted surgically, and the functioning of the system tested for a period of 3 months. X-ray examinations following epidural contrast injections showed a distribution up to Th4 following 1.5 ml and Th8–9 following 1.0 and 1.25 ml. Epidural injection of lidocaine throughout the study period proved the system to be functioning for all 3 months. Another 12 rabbits were included for the neurotoxicological examinations following epidural catheterization, without any injections (three rabbits), epidural injections of saline (four rabbits) and meptazinol (five rabbits) once a day for 14 days. Histopathological examinations showed a fibrous cocoon, at the tip of the catheter, in all rabbits. In the group of rabbits which did not receive any injections, the cocoon was slightly infiltrated with leukocytes and local depression of the spinal cord was observed in one rabbit. In the saline-injected group this infiltration was more pronounced and in one rabbit it extended into the meninges. Three rabbits showed local depression of the spinal cord and local myelopathy of the white matter in the area adjacent to the cocoon. In the group of rabbits receiving meptazinol, three out of five had local depression and myelopathy of the white matter. In this group these findings were more pronounced. In two rabbits the myelopathy extended transversely through the white matter into the grey matter of the spinal cord. The number of pathological changes in the group receiving meptazinol was significantly higher compared to the control and placebo groups. The epidural catheterization technique proved to be simple and reliable. Neurotoxicological examinations showed local effects following catheterization and injection of saline. Following injection of meptazinol, a significant neurotoxicological potential was shown.     

丙酸氯倍他索乳膏家兔体内药代动力学

目的研究丙酸氯倍他索乳膏家兔体内药代动力学特性。方法采用高效液相色谱法。结果单次给药后2h左右达峰，经多次给药后家兔体内的血药峰浓度及谷浓度呈上升趋势。结论显示丙酸氯倍他索在家兔体中有蓄积作用。     

Stimulation of PAI-1 in rabbit anti-GBM glomerulonephritis

It has previously been shown in human disease and animal models of glomerulonephritis (GN) that fibrin deposition is associated with a net reduction of glomerular fibrinolytic activity as a result of reduced expression of plasminogen activators and increased expression of plasminogen activator inhibitor type 1 (PAI-1). Conditioned media (CM) prepared from cultured glomeruli of normal rabbits and rabbits 24 (Day 1) and 96 (Day 4) h after induction of anti-GBM GN were compared for their effects on the synthesis of fibrinolytic molecules in human endothelial cells (EC). Only CM from Day 4 GN rabbits showed PAI-1 protein stimulatory activity of up to 148% ( P <0.05; n =3) above that of untreated EC. This was also seen at the mRNA level. Glomerulonephritis Day 4 CM showed significantly higher amounts of tumour necrosis factor (TNF) and thrombin and transforming growth factor-β (TGF-β) bioactivity in comparison to glomerular CM from normal rabbits. After high performance liquid chromatography (HPLC) of Day 4 GN CM, PAI-1 stimulatory activity was found to correlate with the presence of interleukin 1 (IL-1), TNF and TGF-β. These results suggest a correlation between severity of anti-GBM GN in a rabbit model, increased PAI-1 synthesis and increased expression of TNF and TGF-β. This may potentiate glomerular fibrin and extracellular matrix deposition in anti-GBM GN, leading to glomerular crescent formation and eventual renal failure.     

The Haemostatic Effect of 51Cr-Labelled Blood Platelets An Experimental Study in the Rabbit

The haemostatic effect of ⁵¹Cr-labelled platelets was studied in 5 rabbits made thrombocytopenic (35,000/μl blood) by whole body ionizing irradiation. Bleeding times were recorded after standardized cuts on the inner side of the rabbit's ear, a method with an acceptable reproducibility. The animals were then each transfused with concentrates of labelled platelets from 2 healthy donor rabbits. This increased the platelet counts to about 2 times 10⁵/μl blood. Bleeding time values were markably prolonged before transfusion and became normalized when tested 1 and 4 h after transfusion. In 3 control experiments, where unlabelled platelet rich plasma was transfused to thrombocytopenic recipients, a similar shortening of the bleeding time was observed. It is concluded that ⁵¹Cr-labelled platelets retain haemostatic ability comparable to non-labelled platelets, when circulating in a recipient animal.