Intracranial microcapsule drug delivery device for the treatment of an experimental gliosarcoma model

Controlled-release drug delivery systems are capable of treating debilitating diseases, including cancer. Brain cancer, in particular glioblastoma multiforme (GBM), is an extremely invasive cancer with a dismal prognosis. The use of drugs capable of crossing the blood-brain barrier has shown modest prolongation in patient survival, but not without unsatisfactory systemic, dose-limiting toxicity. Among the reasons for this improvement include a better understanding of the challenges of delivery of effective agents directly to the brain tumor site. The combination of carmustine delivered by biodegradable polyanhydride wafers (Gliadel(?)), with the systemic alkylating agent, temozolomide, allows much higher effective doses of the drug while minimizing the systemic toxicity. We have previously shown that locally delivering these two drugs leads to further improvement in survival in experimental models. We postulated that microcapsule devices capable of releasing temozolomide would increase the therapeutic capability of this approach. A biocompatible drug delivery microcapsule device for the intracranial delivery of temozolomide is described. Drug release profiles from these microcapsules can be modulated based on the physical chemistry of the drug and the dimensions of the release orifices in these devices. The drug released from the microcapsules in these experiments was the clinically utilized chemotherapeutic agent, temozolomide. In vitro studies were performed in order to test the function, reliability, and drug release kinetics of the devices. The efficacy of the temozolomide-filled microcapsules was tested in an intracranial experimental rodent gliosarcoma model. Immunohistochemical analysis of tissue for evidence of DNA strand breaks via terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed. The experimental release curves showed mass flow rates of 36?μg/h for single-orifice devices and an 88?μg/h mass flow rate for multiple-orifice devices loaded with temozolomide. In vivo efficacy results showed that localized intracranial delivery of temozolomide from microcapsule devices was capable of prolonging animal survival and may offer a novel form of treatment for brain tumors.     

一种亚低温实验装置的研制

目的研制一种亚低温治疗新生动物缺氧缺血性脑损伤(hypoxic-ischemic brain damage,HIBD)的实验装置,对传统选择性头部亚低温的降温方式进行改良。方法根据牛顿冷却定律,利用热对流和热传导的方式,使用冷空气对实验动物进行选择性头部亚低温,由温控器进行脑内温度的监控。选择HIBD动物,监测脑内初始温度(35℃)降至不同温度的时间和相应的头皮温度,并进行统计分析。结果动物头罩内冷气温度可在2~26℃范围内准确调控,脑内温度从35℃降至28℃所需的平均时间小于40 min,脑内温度与头皮温度呈良好的直线正相关关系(r=0934,P005)。结论通过冷空气对实验动物进行选择性头部亚低温是一种有效、简便的方法。     

脊柱三维运动测试实验装置的研制

目的研制一套模拟人体脊柱在体运动的离体加载装置,进行脊柱生物力学实验研究。方法利用轴承原理,在加载盘上设计安装旋转锁定装置,加载时旋转于所需测试位置后用螺栓锁定状态,再通过万能材料试验机提供自动加载动力源,在脊柱标本上施加前屈/后伸、左/右侧弯和左/右轴向旋转6个方向的纯力矩,模拟脊柱的在体运动,并用三维扫描仪对脊柱标本加载前后位置进行扫描测量。利用该加载装置对6具1岁龄猪颈椎(C2-C6)在6种加载状态下进行运动范围测量,并对该加载装置进行精度验证和误差分析。结果建立了一套人体脊柱三维运动实验装置,6具猪颈椎标本经加载测量得到6个方向的中性区和活动范围数据,总测量误差值小于3.5%。结论该装置巧妙的设计较好地模拟了脊柱在体运动,可实现人体脊柱的快速加载,费用低、方法简单实用,能大大提高实验的效率,在脊柱的离体加载方面具有较大的推广应用价值。     

An experimental pilot study on controlled portal vein arterialization with an extracorporeal device in the swine model of partial liver resection and ischemia

AIM: To determine whether the physiologically oxygenated arterial blood reversed in the portal system by means of portal vein arterialization (PVA) through an extracorporeal device which we have called L.E.O2.NARDO (Liver Extracorporeal Oxygen. NARDO) is effective in treating swine with subtotal hepatectomy leading to acute liver failure (ALF). METHODS: Ten swine with ALF induced by 85-90% liver resection and five minutes of ischemia-reperfusion injury were randomly divided into two groups: five animals received PVA extracorporeal treatment and five swine were not-treated (control group). Blood was withdrawn from the iliac artery and reversed in the portal venous system. An extracorporeal device was interposed between the outflow and the inflow in order to monitoring the hemodynamic parameters. Each treatment lasted 6 hours. Serum and liver samples were collected in both groups. The survival was assessed at 1 week. RESULTS: The PVA-extracorporeal treatment yielded beneficial effects for subtotal hepatectomy-induced ALF swine with decreased serum ammonia, transaminases and total bilirubin as compared with the untreated group. INR recovered rapidly in the PVA-extracorporeal group remaining significantly lower than in untreated animals. The 7-day survival of PVA-extracorporeal group swine was significantly higher than that of untreated animals, with a statistically significant difference (p<0.05). Four swine in the PVA-extracorporeal group survived at 1 week while none of the swine in the control group were alive at that time; an average time of 144h+/-13h and 24.4h+/-5h was observed in the PVA-extracorporeal and control groups, respectively. CONCLUSIONS: Arterial blood supply in the portal system through the extracorporeal device is easily applicable, efficacious, safe and may represent a novel approach for ALF swine induced by subtotal liver resection.     

Neuronal cytoskeletal alterations in an experimental model of depression

It has been proposed that depression is associated with hippocampal morphological changes. The apical dendrite atrophy of hippocampal CA3 pyramidal neurons has been described in experimental models of depression. The aim of the present study was to determine which cytoskeletal components are involved in the morphological changes previously described in the hippocampus of depressed animals. The expression of different neuronal cytoskeletal markers was analyzed by immunohistochemistry in rats exposed to a learned helplessness paradigm, an experimental model of depression. Rats were trained with 60 inescapable foot shocks (0.6 mA/15 s) and escape latencies and failures were tested 4 days after training. Animals in which learned helplessness behavior persisted for 21 days were included in the depressed group. No foot shocks were delivered to control rats. Microtubule-associated protein 2 (MAP-2) and light (NFL; 68 kDa), medium (NFM; 160 kDa) and heavy (NFH; 200 kDa) neurofilament subunit immunostainings were analyzed employing morphometric parameters. In the depressed group, NFL immunostaining decreased 55% (P<0.05) and 60% (P<0.001) in CA3 and dentate gyrus, respectively. In the same areas, MAP-2, NFM and NFH immunostainings did not differ between depressed and control animals. Since NFL is present in the core of mature neurofilament, it is proposed that hippocampal depression-associated plastic alterations may be due to changes in the dynamics of the neurofilament assembly.     

大鼠胫骨标准实验性骨不连模型的制作

背景：建立客观标准的骨不连动物实验模型是骨不连的实验研究及探索骨不连治疗的必要条件。 目的：为骨不连的实验研究建立一种客观的动物实验模型。 方法：选取SD大鼠,在胫骨中段截断,用口腔科粘固粉充填器(3#或4#)灼烧骨折断端(包括骨膜),然后用    0.5 mm克氏针钻入骨髓腔,固定骨折,2个月后经大体标本、病理组织学及放射学检查确定骨不连形成情况。 结果与结论：大体标本观察、放射学检查及病理组织学检查均显示骨缺损区无骨性连接,为纤维瘢痕组织填充,骨端硬化。结果表明实验所建立的动物模型,具有骨不连的病理改变,符合骨不连的要求,是一种可靠而实用的实验性骨不连动物模型。 中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程全文链接：     

Development of an experimental model of brain tissue heterotopia in the lung

The presence of heterotopic brain tissue in the lung is a rare abnormality. The cases reported thus far are usually associated with neural tube defects (NTD). As there are no reports of experimental models of NTD that present this abnormality, the objective of the present study was to develop a surgical method of brain tissue heterotopia in the lung. We used 24 pregnant Swiss mice divided into two groups of 12 animals each, denoted 17GD and 18GD according to the gestational day (GD) when caesarean section was performed to collect the fetuses. Surgery was performed on the 15th GD, one fetus was removed by hysterectomy and its brain tissue was cut into small fragments and implanted in the lung of its litter mates. Thirty-four live fetuses were obtained from the 17GD group. Of these, eight (23.5%) were used as control (C), eight (23.5%) were sham operated (S) and 18 (52.9%) were used for pulmonary brain tissue implantation (PBI). Thirty live fetuses were obtained from the females of the 18GD group. Of these, eight (26.6%) were C, eight (26.6%) S and 14 (46.6%) were used for PBI. Histological examination of the fetal trunks showed implantation of GFAP-positive brain tissue in 85% of the fetuses of the 17GD group and in 100% of those of the 18GD group, with no significant difference between groups for any of the parameters analysed. The experimental model proved to be efficient and of relatively simple execution, showing complete integration of the brain tissue with pulmonary and pleural tissue and thus representing a model that will permit the study of different aspects of cell implantation and interaction.     

Acute cytomegalovirus glomerulonephritis: an experimental model

HA/ICR mice injected intraperitoneally with an LD(10) of murine cytomegalovirus develop a transiet acute glomerulonephritis characterized by cytomegalic intranuclear inclusions limited to mesangial cells. Viruria and proteinuria occur on the 3rd day and usually subside by the 10th day, accompanied by resolution of the glomerular lesion. By electron microscopy, virus synthesized within mesangial cell nuclei accumulates in intercelluar channels that course through the mesangial matrix. Virus and cellular debris are also found in channels surrounded by matrix in the juxtaglomerular area and between the epithelial cells of the macula densa. By immunofluorescence, viral antigen first concentrated in glomerular mesangial cells on the 5th day is cleared centripetally, appearing as fine granules in the juxtaglomerular area by the 7th day after infection. By the 10th day, changes are restricted to the juxtaglomerular region, and thereafter hyalinization at the glomerular vascular pole or cellular disarray of the juxtaglomerular zone with lymphocytic infiltration extending into the renal interstitium from few glomeruli occurs in approximately 40 per cent of the mice associated with persistence of viral antigen in these foci. These findings indicate that at least one route of transport resulting in viruria involves the glomerular mesangium, juxtaglomerular zone, and the distal convoluted tubule. Persistence of viral antigen or other noxious substances along this route may result in a unique juxtaglomerular lesion and interstital nephritis.     

Translocation of indigenous microflora in an experimental model of sepsis

Translocation of viable bacteria from gut to bloodstream and other sterile body sites during shock has been demonstrated in several experimental and clinical studies. The factors causing translocation and its incidence at different stages of shock are not known. The aim of the study was to evaluate the importance of several factors causing translocation of indigenous microflora in an experimental model of septic shock based on intraperitoneal Escherichia coli sepsis in rats. Counts of inoculated E. coli and translocated bacteria in different locations, gut morphology and haematological values were evaluated at different stages of sepsis. Sepsis developed in all animals and E. coli achieved the highest counts in blood 6 h after inoculation. Translocation was commonest at 6 and 12 h after inoculation. Frequently translocating bacteria were lactobacilli, bifidobacteria, bacteroides and peptostreptococci. In early sepsis, translocation was associated with high E. coli counts in blood, yet in late sepsis the opposite correlation was present. Low infiltration by neutrophils in the ileum and decreased mitotic activity in the colon were associated with a high translocation rate. In early sepsis, translocation was associated with low lymphocyte counts, but in late sepsis, with low neutrophil counts. Translocation of bacteria (including anaerobes) that colonise the gut in high counts takes place during sepsis. Putative influencing factors such as activity of the primary disease (bacterial counts in blood), gut morphology or haematological values seem to have different impacts on translocation, depending on the stage of the disease.     

实验性牙周炎大鼠模型的建立

背景：建立实验性牙周炎大鼠模型是研究牙周病的基本方法之一,目前常用的建模方法存在许多弊端,需要进一步改进。 目的：建立一种近似于人类临床的牙周炎动物模型方法。 方法：将20只8周龄的Wistar大鼠随机分为实验组和对照组,锐分离实验组大鼠双侧下颌第一磨牙颊侧牙龈,局部黏结慢性牙周炎患者的牙石于牙颈部,滴入慢性牙周病炎患者的唾液10 μL/次,2次/d;对照组大鼠牙齿不做处理。两组大鼠均喂以高糖黏性食物。 结果与结论：造模14 d后实验组动物一般生物学特征和牙周组织病理、X射线变化均符合典型牙周炎表现。局部黏结牙石加混合细菌感染的方法建立的大鼠牙周炎模型可以模拟人类牙周炎的组织变化,是一种接近于人类临床的简单、实惠、有效的建模方法。     

Colistin efficacy in an experimental model of Acinetobacter baumannii endocarditis

The in-vivo activity of colistin was evaluated in an experimental rabbit model of Acinetobacter baumannii endocarditis with a strain susceptible to colistin and intermediate to imipenem. Compared to a control group, colistin was effective (p < 0.05) in bacterial clearance from blood and in the sterilisation of blood cultures, but was not effective in clearing A. baumannii from vegetations. Thus, although colistin may be effective in treating bacteraemia caused by susceptible strains of A. baumannii, it may not be a suitable treatment for endocarditis, perhaps because of poor penetration into vegetations and a low C(max)/MIC ratio in tissue.     

Immunomodulatory effect of Hawthorn extract in an experimental stroke model

Background  

Recently, we reported a neuroprotective effect for Hawthorn (Crataegus oxyacantha) ethanolic extract in middle cerebral artery occlusion-(MCAO) induced stroke in rats. The present study sheds more light on the extract's mechanism of neuroprotection, especially its immunomodulatory effect.     

Evaluation of cerebral vasospasm with transcranial magnetic stimulation: an experimental study

Despite the current use of several different methods for diagnosis and follow-up of cerebral vasospasm after subarachnoid hemorrhage, an easy, quick, reliable, and noninvasive method is still needed for evaluation of this entity. We investigated the value of transcranial magnetically evoked motor potential changes during the vasospasm period in a rabbit experimental subarachnoid hemorrhage model. We also recorded motor evoked potential changes after deferoxamine treating during vasospasm. Our results reveal a significant increase in latency periods of evoked potentials during the angiographically proven vasospasm period (34.5%) over those in sham-operated rabbits (9.5%). With deferoxamine treatment, only a minor increase in latency periods (4.5%) was detected after subarachnoid hemorrhage. These results suggest the potential value of evoked motor potential recording as a diagnostic tool in cases of cerebral vasospasm. Received: 20 May 2000 / Accepted: 12 December 2000     

Histopathology of the airway epithelium in an experimental dual-phase model of bronchial asthma

BACKGROUND: Lesions of trachea cuticles are a pathological histological characteristic of bronchial asthma. Furthermore, collected tracheal cuticles desquamated from the respiratory tract are found in patients' sputum when asthma attacks occur or after the induction of allergen inhalation. From these facts, it is assumed that desquamation of trachea cuticle cells is a pathological symptom of bronchial asthma. However, there has not been any chronological report of desquamation of trachea cuticles through the process of bronchial asthma attacks. OBJECTIVE: For this report, we made an experimental bronchial asthma model using guinea pigs, and conducted chronological examinations of trachea cuticle lesions related to pathological symptoms of bronchial asthma using a transmission electron microscope and a scanning electron microscope. METHODS: The experimental asthma models were made by injection of ovalbumin into the abdominal cavity of guinea pigs. Then the airway responses to inhaled aerosolized ovalbumin were induced. The trachea were enucleated and examined under an optical microscope, a transmission electron microscope (hereafter abbreviated as TEM), and a scanning electron microscope (hereafter abbreviated as SEM) after 1, 2, 4, 8, 12, 24 h and 7 days after the immediate airway responses. RESULTS: Intercellular oedema of ciliated epithelium was observed in the sensitization groups immediately after the immediate airway response. SEM observation revealed increased mucus secretion and shortening of cilium. A slight case of desquamation or deciduation of ciliated epithelium was also beginning to appear. TEM observation revealed a dilation of ciliated epithelium intervals. Infiltration of eosinophilic leucocytes was already detectable beneath the ciliated epithelium. The degree of ciliated epithelium desquamation and infiltration of eosinophilic leucocytes progressed with time. When the late airway response occurred 4 hours later, eosinophilic leucocytes had increased drastically, and ciliate epithelium had desquamated to the extent that basal cells were exposed. Seven days after the immediate airway response, epithelium intercellular oedema had improved, and cilium had been reproduced. CONCLUSION: These results suggest that desquamation of epithelium caused by trachea cuticle lesions appears at an early stage of an asthma attack, owing to the contraction of the trachea, and that the damage is intensified by the infiltration of eosinophilic leucocytes.