Comparative pharmacokinetics of submucosal vs. intravenous flumazenil (Romazicon) in an animal model

PURPOSE: This study was performed to determine the bioavailability and local tissue toxicological safety of flumazenil (Romazicon) when administered by oral submucosal (SM) as opposed to intravenous (i.v.) injection. METHODS: Six dogs each received SM flumazenil (0.2 mg), and their serum was collected at predetermined time intervals (0-2 h) and frozen (-70 degrees C). Seven days later, the dogs received an identical dose of i.v. flumazenil, and serum samples were again collected, as above. Comparative quantitation of flumazenil levels (i.v. vs. SM) was made using a sensitive HPLC assay (UV detection). Direct/local drug toxicity was visually scored by unbiased raters of color photographs (test and control mucosa) taken at 1, 2, and 7 days following SM flumazenil injection. An oral pathologist examined slides processed from control and treatment tissues (hematoxylin and eosin staining) taken (punch biopsy) 1 week following SM injection to compare with direct clinical scores. RESULTS: Serum flumazenil levels reached a plateau (8.5 +/- 1.5 ng/mL, mean +/- SD) within 4 min of SM drug injection and declined thereafter to -2 ng/mL by 2 h. Bioavailability of SM flumazenil was 101 +/- 14%, based upon measuring the area under the serum concentration-time curves over 1.5 h (AUC 0-1.5 h, SM vs. i.v. drug). Thus, serum drug levels following SM drug administration were broadly comparable to those obtained during the elimination phase of corresponding i.v. drug delivery. Regarding drug tissue toxicity, no evidence of direct drug toxicity was observed by unbiased raters of color photographs (test and control mucosa) taken at 1, 2, and 7 days following SM flumazenil injection. Following pathologic review, no difference was seen in the degree of inflammation between treatment and control tissue. CONCLUSION: At the quantity and concentration used, SM drug flumazenil administration appears to be both a safe and a viable alternative to bolus i.v. drug delivery and worthy of further investigation.     

Dental caries in an animal model

Sprague-Dawley rats were inoculated with Streptococcus mutans (serotype g) and the effect of different concentrations (20, 40 and 56%) of sucrose in the diet on the establishment of this strain into the oral cavity of rats was studied. The Streptococcus mutans was well established in all the experimental groups and we found an almost linear correlation between the sucrose concentration and the severity of dental caries. Another factor that played an important role on the establishment of Streptococcus mutans into the mouth of rats was the inoculum size used. In this work a concentration of 4 x 10(10) showed a consistent establishment onto the teeth of this animal model.     

Platelet-rich and platelet-poor plasma: development of an animal model to evaluate hemostatic efficacy

Hemostasis is important for any surgical procedure. One method uses autologous platelet-rich and/or platelet-poor plasma sprayed on the wound site. Although effective, there are little quantitative data available to fully document the extent to which these autologous products function as hemostats. Also, limitations in current animal models make quantitative study of topical hemostats difficult. A porcine partial-thickness skin wound model was developed to compare the hemostatic ability of these treatments with untreated control wounds. Rectangular partial-thickness dermal wounds were created in the back of a pig, which was then sprayed with activated platelet-rich plasma, activated platelet-poor plasma, or left untreated. Bleeding was quantified by two methods: 1) gravimetric measurement of exudate transfer to a sponge over a 15-minute interval, and 2) iron assay of the exudate over this same interval. Values for treated wounds were normalized to those of control wounds to minimize interanimal variability. Both gravimetric and iron assay measurements demonstrated that platelet-rich plasma was effective within 5 minutes after application with normalized bleeding values of approximately 35% and 20%, respectively, of the untreated controls. Corresponding values for platelet-poor plasma were approximately 90% and 65%, respectively, with differences only significant for the iron assay method measured on 10- and 15-minute wound exudate. Although both platelet-rich and platelet-poor plasma demonstrated hemostatic potential, the effect was more robust with the former. Iron assay was a more accurate method of measuring bleeding than gravimetric analysis.     

眶下孔周围注射滑石粉制作新型大鼠三叉神经痛动物模型的实验研究

目的: 应用滑石粉悬液进行眶下孔周围注射,建立一种新型大鼠三叉神经痛（trigeminal neuralgia,TN）动物模型。方法: 选取Wistar雄性大鼠30只,随机分为2组,一组在眶下神经孔周围注射30%滑石粉混悬液0.3 mL,另一组注射同等剂量的生理盐水,于术前3 d、术后3 d及术后1、2、3、4、6、8、12周分别进行行为学观察,Von Frey纤维测定大鼠机械性刺激反应阈值,利用方差分析对机械刺激阈值进行统计学分析。于术后3 d及术后4、8、12周取眶下孔周围组织作组织病理学观察,应用免疫组织化学的方法检测眶下区组织肿瘤坏死因子α(TNF-α)、白细胞介素1β(IL-1β)的表达,采用SPSS16.0软件包对各检测值进行分组t检验。结果: 实验组大鼠术后3 d眶下神经支配区域机械痛反应阈值与术前及对照组相比显著降低（P<0.01),大鼠易激惹,具有搔抓面部或攻击行为。直到术后12周,机械痛阈值仍然显著低于对照组。实验组术后3 d组织病理学观察主要呈炎症表现,炎性因子表达减少;术后1周炎症更剧烈,炎性因子表达。术后4周,局部出现炎性肉芽组织增生,炎性因子表达最高;4~12周炎性反应逐渐减轻,炎性因子表达逐渐减少,局部瘢痕形成并逐渐加重,可见瘢痕压迫眶下神经。结论: 眶下孔周围注射滑石粉悬液可以建立稳定的TN动物模型,该造模方法简单易行,为进一步研究TN发病机制和模拟临床治疗提供了一种可靠、有效的动物模型。     

髁突矢状骨折动物模型的实验研究

目的：建立髁突囊内矢状骨折动物模型,观察髁突骨折后不同时间的病理形态改变。方法：对10只绵羊进行实验,右侧关节为手术侧,从耳前区切开皮肤,到达颞下颌关节,切断关节盘前后附着,从髁突外侧嵴到内侧髁颈锯开髁突,建立斜形矢状骨折。髁突碎片和关节盘推向前下内侧,左侧关节为对照侧。分别于术后1周、4周和12周处死2只、4只和4只动物。记录术前和术后每组动物的体质量、最大开口度、侧方活动度,进行X线、CT和组织病理学观察。采用SPSS12.0软件包对数据进行统计分析。结果：各手术组体质量、左侧向活动度未发现显著差异,但是在4周和12周组中,最大开口度和右侧向活动度明显减小。在这2组中,X线检查发现髁突残端外侧有新骨生成,并向外侧生长,同时关节间隙变狭窄和模糊。三维CT检查发现,髁突残端、髁突碎片和关节结节均发生改建。组织病理学观察发现,在4周和12周组动物,关节腔充满纤维组织、软骨和骨组织。结论：该研究表明,此类骨折可以导致髁突骨关节病理改变,颞下颌关节有发展为关节强直的可能。     

Histochemical characterization of pig masseter muscle: an animal model

Masseter muscle autopsies were obtained from six different areas of six pigs. The autopsies were stained for the demonstration of myosin ATPase activity by means of a conventional histochemical technique. As compared with human masseter, the pig masseter muscle contained more type II fibers. But, like the human masseterMasseter muscle autopsies were obtained from six different areas of six pigs. The autopsies were stained, the pig muscle had a varying distribution of fiber types in the different autopsy areas, a distribution which might be the result of an adaptation to carry out special functions such as chewing, swallowing, and jaw posture. The fiber type distribution in the pig masseter also varied among individuals, probably reflecting various levels of utilization of the muscles besides different genetic influences. Moreover, pig masseter contained fibers of intermediate staining intensity (IM fibers), a fiber type rarely seen except in human masticatory muscles. In conclusion, we consider the pig masseter to be a useful animal model to study muscular adaptations to altered function in the orofacial region.     

Effects of pentoxifylline and tocopherol on an osteoradionecrosis animal model

PurposeOsteoradionecrosis (ORN) is known to be a refractory disease in the oral and maxillofacial field. The purpose of this study was to examine the effects of pentoxifylline (PTX) and tocopherol (TP) on an ORN animal model focused on bone healing.Materials and methodsA total of 48 Sprague–Dawley rats were used: 40 received a single irradiation dose of 35 Gy on the left mandible, and eight were used as the nonirradiated control group. The rats received PTX (T1, C1), TP (T2, C2), a combination of PTX and TP (T3, C3), or normal saline (T4, C4). Three weeks after irradiation, the mandibular posterior teeth were extracted. The rats were sacrificed 4 weeks after extraction.ResultsIn the T3 group, bone volume/tissue volume was 19.62 ± 16.03 (%), bone mineral density was as 0.31 ± 0.16 (g/cm³) in the micro-CT analysis, which were higher than that of other groups (p = 0.025, p = 0.012, respectively). In the histological analysis, bone regeneration was the most prominent in the T3 group. The ratio of empty lacunae was the highest in the T4 group, 68.77 ± 15.47 (%, p = 0.004). Immunohistochemistry showed that the expression of TNF-α was relatively lower in the T3 than in the T4 or T2 groups. The RT-qPCR showed the expression level of PECAM, VEGF-A, and osteocalcin was more than twofold as high as in the T3 group compared to the other groups.ConclusionThe combination of PTX and TP appears to promote angiogenesis and osteogenesis in a rat ORN model. Therefore, PTX and TP might be useful in the treatment and prevention of ORN.     

The pathogenesis of oral pulse granuloma: an animal model

Oral pulse granuloma is one of the terms used to describe oral inflammatory lesions characterized microscopically by the presence of giant cells and hyaline rings. The various names proposed for these lesions reflect the lack of agreement regarding their pathogenesis. One theory advanced claims that the process represents a foreign-body granulomatous reaction to implanted vegetable particles, more specifically those of pulses/legumes. In this study an animal model was developed where homogenized cooked legumes were implanted into the orofacial region of rats. Animals were killed at varying intervals ranging from one day to six months and the tissues associated with the implanted material were removed and processed for light microscopy. The experimentally produced lesions had many features similar to those found in humans, the similarities becoming more pronounced with time. The results indicate that the cellulose moiety of food particles of plant origin accidentally implanted into human tissues may cause the granulomatous reaction known as oral pulse granuloma.     

Evaluation of minipigs as an animal model for alveolar distraction

OBJECTIVE: Alveolar distraction osteogenesis is a relatively novel tissue regeneration technique that remains, in some respects, at an experimental stage. The selection of an experimental animal biomodel is not clearly defined, with reports in the reviewed literature on dogs, sheep, and monkeys. The present objective was to compare 2 experimental biomodels (dog and minipig) using an alveolar distraction protocol with a novel prototype distractor. STUDY DESIGN: Three beagle dogs and 3 G?ttingen minipigs were evaluated, placing the distractor at the right hemimandible alveolar ridge after previous extraction of premolars. The radiological examination was carried out immediately after the distraction and at 2 weeks of consolidation. RESULTS: Satisfactory clinical and radiological results were obtained in 2 of 3 beagle dogs after the previous unilateral extraction of mandibular and maxillary premolars. During the consolidation, a height gain of approximately 5 mm was observed, with the appearance of radiodense bone trabeculae in the distraction chamber. The distraction failed in all of the minipigs. CONCLUSION: The minipig was not an appropriate biomodel for the study of alveolar distraction because the investigators were not able to maintain the seal of the distraction chamber or the stability of the distractor.     

实验性即刻再植牙大鼠模型的建立

目的:建立大鼠即刻再植牙动物模型,观察再植牙的愈合过程与牙根外吸收的表现。方法:30只6周龄SPF级Wist-ar雄性大鼠,分为6组,每组5只。单侧上颌第一磨牙脱位后即刻再植,对侧同名牙为自身对照。分别于术后1、3、7、14、21、28d处死,分离上颌骨;拍根尖X线片,应用图像分析系统测量近中根根尖周阴影面积;标本切片、HE染色,进行组织学观察。结果:近中根根尖周阴影面积随时间延长而增大,近中根牙根表面吸收陷窝增多,牙周膜局部宽度变窄,新生骨样组织增加。结论:本法成功建立再植牙动物模型,该模型稳定可靠,能完整反映再植牙愈合方式,为进一步研究再植牙愈合机理提供了很好的研究模型。     

Decreased expression of 5-HT1A in the circumvallate taste cells in an animal model of depression

ObjectiveIt has been reported that stress can cause anhedonia, a core symptom of depression, and also affect taste responses of the stressed subjects. Anhedonia refers to a reduction of the ability to experience pleasure, which can be detected by decreased response to palatable food in rats. The present study was conducted to examine if stress-induced anhedonia is accompanied by changes in gene expression for taste.DesignFor anhedonia test, rats had free choices of cookies, a palatable food, and chow for 1 h following 1 h of daily restraint sessions. To examine the development of behavioral depression by restraint stress, ambulatory activity and forced swim tests were performed. Taste cells were harvested from the circumvallate papillae of rats on the 1st, 3rd and 7th day of stress exposure and subjected to the analysis of gene expression for taste.ResultsOne hour of daily stress exposure did not affect chow intake during the entire experimental period. However, from day 2 cookie intake was suppressed, suggesting the development of anhedonia. Ambulatory activity was significantly decreased, and immobility during forced swim test was increased, after the 7th day of stress exposure, but not before. 5-HT1A mRNA expression, but not T1R2, T1R3, T2R6, α-gustducin or PLCβ2 mRNA expression, appeared to be decreased after the 3rd day of stress exposure.ConclusionReduced expression of 5-HT1A in the taste cells, possibly leading to a reduced processing of taste information for palatable food, may additively contribute to the development of anhedonia as a pre-symptomatic feature of depression in stressed subjects.     

Salivary secretion effects of the antipsychotic drug olanzapine in an animal model

Oral Diseases (2012) Objective: Olanzapine, introduced as an alternative to clozapine in schizophrenia therapy, is thought to display a receptor affinity similar to that of clozapine. Antipsychotics are well‐known xerogenic drugs. However, clozapine exerts both antagonistic and agonistic salivary effects (‘clozapine‐induced sialorrhea’), the latter probably via muscarinic M1 type of receptor. We hypothesise that olanzapine also has dual salivary effects. Material and methods: Effects of intravenous olanzapine were examined in rats, including those subjected to chronic preganglionic parasympathetic denervation (submandibular glands) or combined postganglionic parasympathetic and sympathetic denervation (parotid glands). Secretion was evoked reflexly, and by intravenous methacholine and the tachykinin substance P. Results: At 0.01–1 mg kg^?1, olanzapine dose dependently reduced secretion in response to methacholine or reflex stimulus but not that to substance P. At 10 mg kg^?1, olanzapine evoked a long‐lasting secretion, independent of the autonomic innervation as well as of α‐ and β‐adrenergic receptors and muscarinic receptors. The secretion was reduced, but not abolished, by a substance P receptor antagonist. Conclusions: Like clozapine, olanzapine evoked secretion. The response to olanzapine was greater and, in contrast to clozapine, involved non‐traditional gland receptors (such as substance P receptors). The findings imply that olanzapine plays an excitatory role via tachykinin receptors in humans.     

放射照射后牵张下颌骨成骨犬实验动物模型的建立

目的：建立放射照射后牵张下颌骨成骨犬实验动物模型。方法：选取成年中国犬12只,实验组10只以60 Co 颊舌向照射下颌骨后部标定区域,照射方法为22．8 Gy、5．7 Gy／次,共4次（生物等效剂量为50 Gy／25次）。对照组2只不照射。照射完成后3个月,在动物下颌第五和第六臼齿间行骨皮质切开术,植入骨牵张器,经过1周的延迟期,2次／d,每次0．5 mm 的速率连续牵张下颌骨10 d,然后固定8周。处死动物,以放射学,组织学和 SPECT 方法对牵张区新骨进行检查,对下牙槽神经进行组织学检查。结果：除实验组1只动物因麻醉意外死亡,其他动物都完成了实验。实验组和对照组新骨形成无明显差异。SPECT 显示实验组成骨活跃。观察到下牙槽神经修复性组织学变化。结论：放射照射后牵张犬下颌骨可形成新骨。     

头颈部恶性肿瘤化学治疗给药途径的应用

头颈部恶性肿瘤是常见的恶性肿瘤之一,具有较高的发病率和死亡率.化学治疗在头颈部肿瘤的综合序列治疗中占有重要地位,给药途径的改进对头颈部恶性肿瘤的化学治疗具有极其重要的意义,给药途径不同,其临床疗效亦不相同.头颈部恶性肿瘤化学治疗给药途径可简单分为:静脉化学治疗、动脉灌注化学治疗、淋巴化学治疗、局部化学治疗和多途径联合化...     

兔双侧下颌骨牵张成骨实验动物模型的建立

目的:建立兔双侧下颌骨牵张成骨实验动物模型。方法:选用16只成年雄性新西兰大白兔,随机分为4组,每组4只。在双侧下颌骨第一前磨牙前方无牙区行骨切开术,用自制牵张器固定。经过7d潜伏期,以每次0.5mm的速度牵张,每天2次,连续7d。分别在潜伏期末、牵张结束、固定期第14天、第28天处死动物,切取标本行X线和组织学观察。结果:全部动物的下颌骨被成功延长,牵张间隙逐渐被新生骨组织充填。结论:该方法建立的动物模型具有可行性和可重复性。     

Surgical induction of temporomandibular joint ankylosis: an animal model.

PURPOSE: The aim of this study was to develop an animal model of temporomandibular joint (TMJ) bony ankylosis for future evaluation of surgical reconstructive methods. MATERIALS AND METHODS: An animal model was selected on the basis of 2 sequential experiments. Four goats and 4 minipigs were used in the first experiment, in which 1 goat and 1 minipig served as control animals. Condylectomy with disc preservation was performed on 1 side of 3 animals in each group. On the contralateral TMJ, condylectomy with discectomy was performed, and the arthroplasty gap was filled with the autogenous bone chips. In the second experiment, TMJ ankylosis was induced bilaterally in 3 additional animals of the species that achieved better ankylosis results in the first experiment. All animals were killed postoperatively at 3 months, and the TMJ complexes were examined by plain radiography, computed tomography, and histological evaluation. RESULTS: In the first experiment, only fibrous ankylosis was observed in the bone-grafted side of 2 goats and 3 minipigs, whereas fibro-osseous ankylosis was achieved in the remaining goat. The extent of ankylosis was found to be more severe in the goats than the minipigs. Hence, goats were selected for bilateral surgery in the second experiment, which achieved consistent bony ankylosis of the TMJ in all animals. CONCLUSIONS: Goats provide a better TMJ bony ankylosis model than minipigs. Consistent bony ankylosis can be induced by bilateral condylectomy, disectomy, and bone grafting of the arthroplasty gap.