Intralesional cidofovir for the treatment of severe juvenile recurrent respiratory papillomatosis: long-term results in 4 children

OBJECTIVE: We sought to determine the efficacy of intralesional injection of cidofovir in improving resolution of recurrent respiratory papillomatosis (RRP).Study design and setting We conducted a prospective, observational trial at an academic tertiary children's hospital. RESULTS: Four children with RRP requiring more than 6 surgical excisions per year were treated with intralesional cidofovir. Cidofovir (5 mg/mL) was injected into airway sites where papillomas had just been excised using sharp technique. Each patient had 6 treatments performed 6 to 8 weeks apart. Biopsies confirmed benign papilloma lesions in all cases. During treatment with intralesional cidofovir there was diminished growth of the papillomas in each patient. Once cidofovir treatment was stopped, the rate of regrowth and frequency of surgical excision returned to pretreatment levels in 3 of the 4 patients. CONCLUSIONS: Intralesional cidofovir may provide benefit in reducing the rate of RRP growth while under treatment, but RRP severity returned to pretreatment levels once cidofovir treatment was stopped using this treatment program.     

Intra-articular hyaluronate in experimental rabbit osteoarthritis can prevent changes in cartilage proteoglycan content

OBJECTIVE: The purpose of this study was to determine the effects of intra-articular injections of high molecular weight (2000 kDa) sodium hyaluronate (HA) on the progression of articular cartilage degeneration in a rabbit partial medial meniscectomy model of osteoarthritis. DESIGN: Six experimental groups included normal, sham operated, and operated and injected animals, the latter injected once-weekly (for two weeks or twelve weeks, beginning four weeks after surgery) with either 1% (w/v) HA or phosphate buffered saline (PBS). Following assessment of gross morphology, serial adjacent blocks of full-depth articular cartilage were prepared from the tibial condyle for analysis of total water, hydroxyproline, DNA and proteoglycan (uronic acid) content, as well as the ratio of galactosamine to glucosamine. Samples were sub-divided into inner (medial) and outer (lateral) regions. RESULTS: No morphological differences were recognized between joints injected with PBS and those receiving HA. When analysed biochemically, there were no significant differences in hydration, hydroxyproline or DNA content between the experimental groups. In contrast, HA injection did affect changes in proteoglycan content. Expressed per tissue dry weight, uronic acid content in the operated group injected with PBS for two weeks was lower than normal (P<0.02), a result not seen in the corresponding HA injected group. After 12 weeks of PBS injections, uronic acid content (per dry weight) was higher than normal (P<0.01), an effect again not observed in the corresponding HA injected group. Results for the galactosamine: glucosamine ratio showed a reduction after 12 weeks of injections, but no differences between PBS and HA injected groups. CONCLUSIONS: Once-weekly, intra-articular injection of high molecular weight HA can prevent changes in proteoglycan content in tibial condylar articular cartilage, compared to PBS injected controls, in the rabbit partial meniscectomy model of osteoarthritis.     

Tissue toxicity of antiseptic solutions. A study of rabbit articular and periarticular tissues

The gross, histologic, and biochemical effects of four commercially available antiseptic solutions on rabbit knee articular and periarticular connective tissues were investigated. Rabbit knee joints were injected with 2.0 cc of either Betadine prep solution, Betadine scrub solution, pHisohex or 3% hexachlorophene. The opposite knees were injected with sterile saline. All animals were injected three times at 48-hour intervals and sacrificed 10 days after the last injection. The solutions containing detergents, Betadine scrub, and pHisohex caused severe gross and histologic damage to articular cartilage, synovia, and muscle. The hexachlorophene loss solution caused moderate histologic damage, but caused articular cartilage ground substance. Betadine prep solution caused only minimal gross and histologic damage, without any biochemical evidence of articular cartilage damage. If antiseptic solutions are to be used in irrigating or packing joint injuries, the use of Betadine prep is recommended.     

The systemic and local effects of an intramedullary injection of methylprednisolone acetate in growing rabbits

Intramedullary injection of methylprednisolone acetate (Depo-Medrol) is successful in the treatment of children with unicameral cysts, but its mechanism of action remains obscure. Using a rabbit model, methylprednisolone was injected into the intramedullary canal of the left proximal tibia. Normal saline was injected into the right proximal tibia as a control. Venous blood samples following injection revealed that corticosteroid was rapidly cleared from bone. Serum methylprednisolone levels rose rapidly, giving a dose-response curve similar to that after an intramuscular injection in humans. Rabbits were killed and analyzed histologically for local changes. There was no fibroblastic proliferation, neovascularization, or other histologic change secondary to injection.     

透明质酸钠与强的松龙治疗兔实验性颞颌关节骨关节炎的研究

目的　探讨透明质酸钠关节内注射治疗兔实验性颞颌关节骨关节炎的效果 ,并与强的松龙进行比较。另对透明质酸钠的治疗机制进行初步探讨。方法　选择 12只日本大耳白兔 ,在双侧颞颌关节上腔各注射1.6 %木瓜蛋白酶溶液 0 .2 ml,3天后右侧再注射 0 .2 ml以诱发程度不同的骨关节炎。除 1只兔意外死亡外 ,11只兔均存活至预期时间。于末次注射后 1周 ,用 6只兔每周在双侧关节上腔各注射透明质酸钠 1.3mg作为实验组。另 5只兔双侧关节上腔各注射强的松龙 1.6 m g作为对照组。连续 4次。疗程结束后第 3、5及 7周分批处死动物 ,对关节进行病理学观察。结果　疗程结束后第 3、5及 7周 ,对照组双侧关节均可见明显结构破坏 ,以右侧较重 ;主要表现为纤维软骨变性 ,软骨变薄或脱落 ,关节面可见以不成熟的纤维细胞和成纤维细胞为主的不完全修复。实验组纤维软骨病变多表现为细胞轻度减少 ,纤维变性 ,甚至局部表层软骨缺损 ,周围软骨细胞簇状增生 ,数量增多 ,骨关节炎病理记分显著低于对照组。结论　透明质酸钠有修复和保护软骨的作用 ,强的松龙无助于软骨的修复 ,反而加重骨关节炎病变     

膝关节腔内注射皮质类固醇对关节软骨损害的研究──病理组织学和超微结构观察

３０只健康新西兰白兔，随机分为两组，每组１５只。Ａ组右膝关节腔内注射醋酸强的松龙，每次７．５ｍｇ／ｋｇ，每周１次；Ｂ组右膝关节内注射生理盐水，每次０．３７５ｍｌ／ｋｇ，每周１次。每组分别于第３、５、７、９、１１周的第１天，各取３只动物，在光镜下观察双侧膝关节和股骨头软骨标本有无病理组织学改变，并在第５、９、１１周加作超微结构观察。结果显示，Ａ组用药２次后即见双侧股骨头、膝关节软骨下区髓腔内脂肪细胞增多，造血组织减少。用药６次后可见右侧膝关节软骨组织出现灶性溶解、坏死。电镜下可见软骨细胞核固缩明显，胞浆内脂滴增多、细胞器坏死、溶解，Ｂ组所有标本未见组织学和超微结构改变。结果提示，关节内注射皮质类固醇对关节软骨的损害是肯定的，且随给药次数的增加而加重。故而，临床疼痛治疗工作中，关节内注射皮质类固醇宜免用。     

Enzymatic recontouring of auricular cartilage in a rabbit model

OBJECTIVE: To evaluate the effectiveness of contouring auricular cartilage in a rabbit model using biologically active enzymes injected subcutaneously. METHODS: The first phase determined the most effective volume and concentration required to affect the cartilage. To accomplish this task, we used ex vivo rabbit ears from a slaughterhouse. In the second phase, we injected 1 mL of hyaluronidase (150 U per milliliter of isotonic sodium chloride solution [saline]), elastase (1 mg per milliliter of saline), or saline into the ears of live rabbits. The study took place at the Madigan Army Medical Center (Tacoma, Wash), and included 10 animals. In each rabbit, we injected the test compound in one ear and saline in the other ear (control). We injected hyaluronidase in 5 ears and elastase in 5 ears. After injection, the ears were contoured and splinted for 4 weeks. In the third phase, we changed the injection pathway in 5 animals. RESULTS: At 4 weeks, 4 (80%) of the 5 ears injected with hyaluronidase showed full response and 1 (20%) had a partial response. Of the 5 ears injected with elastase, 4 (80%) showed a full response while 1 (20%) demonstrated a partial response. There was a response in all 10 of the ears injected with a test compound. Of the 10 control ears, 3 (30%) showed a partial response. At 6 weeks, approximately 6 (30%) of the ears had maintained contour demonstrating a full response. The difference between the test ears and the control ears was statistically significant (P = .006). Compared with the control ears, the results were statistically significant for elastase (P = .004) and hyaluronidase (P = .02). Overall, both agents demonstrated a subjective and objective response compared with control ears. CONCLUSION: This study demonstrates that bioactive enzymes and splinting can be effective in correcting ear deformities in a rabbit model.     

软骨脱细胞基质支架材料的软骨组织工程实验研究

目的应用软骨脱细胞基质作为支架材料，按照组织工程的原理再生软骨，为修复软骨缺损探索新的途径。方法取新西兰大耳白兔1只，体重2．4kg，按改良Courtman法对兔耳软骨行脱细胞处理后用于实验。选用纯种6月龄新西兰大耳白兔18只，雌雄不限，体重2．4～2．6kg。每只耳形成2处1cm&#215;1cm软骨缺损，按修复方式不同随机分为3组，每组24处缺损。A组，软骨脱细胞基质加软骨膜；B组，软骨脱细胞基质；C组软骨膜，作为对照。术后每日观察兔耳修复区的大体变化，并分别于4、12周每组处死3只动物，于修复区切取标本，行HE染色、藏红花红一奥尔新蓝染色、II型胶原基因探针原位杂交实验。结果术后4周内A、B组大体形态无明显改变；术后12周可见修复区轻度增厚，触摸时质地较正常软骨稍硬。C组术后2周，2只2处修复区形成痂皮，术后5周痂皮脱落形成穿孔。术后4周，A、B组HE染色可见软骨脱细胞基质周边有轻度的炎性细胞浸润，以淋巴细胞为主，未形成包囊，藏红花红．奥尔新蓝染色均阴性；C组软骨缺损处的软骨膜塌陷，无细胞增殖现象；各组修复区均未见II型胶原基因探针原位杂交显色。术后12周，A组HE染色示部分软骨脱细胞基质内有新生细胞，细胞排列不规律，ECM嗜碱性增强，藏红花红-奥尔新蓝染色呈阳性，II型胶原基因原位杂交显色示新生细胞内均有大片棕黄色阳性染色区域；B组HE染色示软骨脱细胞基质无吸收现象，周边无包囊，炎性细胞消失，藏红花红一奥尔新蓝染色呈阴性，未见II型胶原基因原位杂交显色；C组HE染色示近软骨断端处可见部分形成新生组织，藏红花红一奥尔新蓝染色呈阳性，II型胶原基因原位杂交显色可见棕黄色阳性染色细胞。结论脱细胞软骨可诱导软骨膜细胞向其中生长而重建软骨，软骨膜和脱细胞软骨复合移植是软骨组织工程的另一种选择。     

Imaging of murine liver tumor using microCT with a hepatocyte-selective contrast agent: accuracy is dependent on adequate contrast enhancement

INTRODUCTION: A major limitation in using both spontaneous and implanted murine liver tumor models in cancer research is the inability to accurately detect and monitor tumor volume. Because microCT without contrast enhancement cannot accurately distinguish tumor from normal liver, we sought to determine the accuracy of contrast enhanced microCT for monitoring liver tumors in mice, performed with intravenous (i.v.) injection of ITG, a hepatocyte-selective contrast agent. METHODS: Twelve female BALB/c mice were injected with 5 x 10(5) CT26 tumor cells in two sites in the liver on day 0, resulting in 24 liver tumors. On days 3, 5, 7, and 10, three mice per day were injected with ITG (0.1 mL ITG/10 g body weight) by tail vein, followed 4 hours later by imaging with microCT (ImTek, Inc.). ITG is transported selectively to hepatocytes by an apoE receptor-mediated process that results in opacification of normal liver parenchyma after i.v. injection. Contrast enhancement on CT scans was graded as good, fair, or poor. After imaging, mice were euthanized to perform gross and histopathologic correlation of liver tumors with CT images. RESULTS: The mean tumor size on microCT and at histopathologic evaluation was 2.2 and 2.3 mm, respectively (P > 0.05). Regression analysis showed no difference between the CT-measured tumor and the actual tumor size (P > 0.05). The overall accuracy for detection of tumor on microCT was 88%, with one false-positive and two false-negative readings. All three erroneous readings on CT scan occurred in mice in which the contrast enhancement of the liver was poor due to inadequate i.v. injection. Although the overall sensitivity and specificity was 90% and 75%, respectively, this was highly dependent on the degree of contrast enhancement. CONCLUSIONS: MicroCT with ITG contrast is an excellent means to monitor tumor diameter in murine hepatic tumor models. However, adequate contrast enhancement is critical for accurate imaging.     

Effects of SKI 306X,a new herbal agent,on proteoglycan degradation in cartilage explant culture and collagenase-induced rabbit osteoarthritis model

OBJECTIVE: Protective effects of SKI 306X, a natural herbal product extracted from three herbs Clematis mandshurica, Trichosanthes kirilowii, and Prunella vulgaris, on articular cartilage was examined and compared with other osteoarthritis (OA) drugs using in vitro and in vivo models. METHODS: In vitro culture of rabbit articular cartilage explants was used as a model to measure the effects of drugs on the matrix degradation. The recombinant human interleukin-1alpha (rhIL-1alpha, 5 ng/ml) was added to induce proteoglycan (PG) degradation and the degree of PG degradation was assessed by measuring the amount of glycosaminoglycan (GAG) released into the culture medium. In in vivo experiment, collagenase was intraarticularly injected twice into the right knee joint of rabbits to induce OA-like change, and test agents were orally administered once a day for 28 days. The degrees of OA-like changes were evaluated through a histological examination. RESULTS: In vitro study revealed SKI 306X inhibited the degradation of PG in a concentration-dependent manner. Trichosanthes kirilowii, which is one of the major components of SKI 306X, also significantly inhibited the GAG release in cartilage explant culture at 0.3 and 0.1 mg/ml. Dexamethasone and NSAIDs, such as diclofenac and rofecoxib, had no significant effects on the suppression of PG degradation. In in vivo studies, OA-like degeneration of the articular cartilage and synovial tissue was induced by injecting collagenase into the right knee joint of mature rabbits. At a dose of 200 mg/kg, SKI 306X reduced the OA-like histological changes, whereas diclofenac had no effect at 10 mg/kg. CONCLUSION: These results indicate that SKI 306X inhibited PG degradation in cartilage explant culture, and its prophylactic administration significantly protected the knee joint of rabbit from OA-like change in collagenase-induced experimental OA model. This strongly suggests that SKI 306X can be a good OA agent with some cartilage protection activity.     

Repair of articular cartilage injury following intra-articular chymopapain-induced matrix proteoglycan loss

The intra-articular injection of 0.02, 0.2, or 2.0 mg of chymopapain (CP) into the knee of adolescent rabbits caused the loss of more than 50% of the proteoglycans (PGs) in the cartilaginous tissues within the joint. Sequential measurements of cartilage-derived keratan sulfate epitope in serum and analyses of articular cartilage slices 2 days after the injection revealed that 0.02 mg of CP was nearly as effective as higher doses (0.2 or 2.0 mg of CP) in causing the depletion. The degradation and depletion of PGs in articular cartilage were shown to be localized to the joint and did not affect articular cartilage in the contralateral knee joint (no injection) or other cartilaginous tissues in the body. On day 9, partial replenishment of the articular cartilage PGs had occurred, irrespective of the dose used, and the articular surface within the joint remained intact. However, by day 21, articular cartilage in joints injected with 2.0 mg of CP had begun to show progressive degenerative changes, and these changes became more severe with time. In contrast, joints injected with 0.2 mg of CP continued to repair successfully by the reestablishment of a matrix that retained its integrity and appeared to remain functional for at least 6 months. These results suggest that the model may prove useful for the study of the repair processes that follow matrix injury and severe depletion of PGs from the articular cartilage matrix.     

关节内注射富含血小板血浆在兔膝骨关节炎动物模型中的作用

目的评估关节内注射富含血小板血浆(PRP)对胶原酶诱导的兔膝骨关节炎(OA)动物模型的影响。方法 20只新西兰大白兔在超声引导下行右侧膝关节内胶原酶注射,建立兔OA动物模型。实验的第4周随机分为PRP组和生理盐水组,每组10只,每周给药1次,共4次。实验第9周取关节软骨观察软骨总体形态及软骨微形态的变化。结果 PRP组软骨总体形态评分为(1.7±0.3)分,明显低于生理盐水组的(3.5±0.6),分,差异有统计学意义(P0.05),提示PRP组软骨总体形态损伤较小;PRP组软骨微形态评分为(3.2±1.0)分,明显低于生理盐水组的(7.4±1.2)分,差异有统计学意义(P0.05),提示PRP组软骨微形态损伤较小。结论关节内注射PRP有保护软骨作用。     

Lidocaine for the prevention of pain due to injection of propofol.

Propofol has a high incidence of pain with injection, particularly into small veins. We sought to determine whether concomitant administration of lidocaine could prevent this pain. In a randomized double-blind trial, 368 women were allocated to one of four groups to receive 19 mL of propofol mixed with either 1 mL of 0.9% saline, 1 mL of 0.5% (5 mg) lidocaine, 1 mL of 1% (10 mg) lidocaine, or 1 mL of 2% (20 mg) lidocaine. The pain of injection was scored as none, mild, moderate, or severe. There was a significant reduction in the overall incidence of pain from 73% with saline to 32% with 20 mg lidocaine. A highly significant negative dose-response relationship between the dose of lidocaine and the severity of pain was demonstrable, both at induction of anesthesia and as recalled in the recovery room (P less than 0.001 for both). Lidocaine (20 mg IV) will significantly reduce the incidence and severity of pain with propofol injection, but about 6% of patients will still suffer unpleasant pain if the dorsum of the hand is used.     

Assessment of blood-induced cartilage damage in rabbit knees using scanning electron microscopy

PURPOSE: To investigate the harmful effects of a single episode of intra-articular bleeding on articular cartilage of rabbit knees using scanning electron microscopy. METHODS: Autologous blood was injected into the right knee joints of 18 New Zealand white rabbits. Surface and cellular damages were examined by the scanning electron microscope (n=9) and light microscope (n=34), respectively. The injected right knees were then compared with the corresponding control left knees at one, 3, and 6 weeks after the blood injection. RESULTS: The articular surface of the injected knees turned uniformly rough with multiple pits after one week. Maximal changes with elevations and depressions were observed at 3 weeks. These changes reversed at 6 weeks with the irregularities smoothing out. A similar pattern of transient cartilage damage was noted histologically. CONCLUSION: Both scanning electron microscopic and light microscopic findings suggest that a single episode of intra-articular bleeding leads to articular cartilage damage but this appears to be reversible. Our findings of transient damage to the articular cartilage suggest that there is no need for intra-articular evacuation and washout following an acute episode of haemarthrosis.     

透明质酸载碱性成纤维细胞生长因子对兔膝关节缺血再灌注损伤防治作用的实验研究

目的：通过动物实验观察碱性成纤维细胞生长因子(bFGF)与透明质酸(HA)关节腔内注射对关节缺血再灌注损伤及退行性关节炎的防治作用。方法：采用夹闭兔股血管8h的方法模拟缺血再灌注模型。将48只新西兰大白兔随机分为对照组(A组)，HA治疗组(B组)和FGF／HA治疗组(C组)，在关节腔内注射相应的药物。用光镜和电镜观察关节滑膜和软骨的病理改变，观察并半定量计算软骨蛋白多糖(PGs)的变化，检测滑膜丙二醛(MDA)的含量。结果：C组的软骨和滑膜病理改变明显轻于A组和B组，在C组中，滑膜MDA的含量明显低于其它两组，而PGs的含量明显高于其它两组：结论：联合应用bFGF和HA能明显减轻兔膝关节缺血再灌注损伤和退行性改变，其作用要明显优于单用HA。     

Alleviation of osteoarthritis by calycosin-7-O-beta-D-glucopyranoside (CG) isolated from Astragali radix (AR) in rabbit osteoarthritis (OA) model

OBJECTIVE: This work was undertaken to assess the protective effect of an isoflavonoid, calycosin-7-O-beta-D-glucopyranoside (CG), isolated from Astragali radix (AR) on the pathogenesis of osteoarthritis (OA)-like lesion in a rabbit model. METHODS: Nine rabbits underwent an anterior cruciate ligament and menisectomy transection (ACLMT) of the rear knee joints to induce OA-like lesion. They were randomly divided into three groups (n=6/group): a negative control group treated with 200 microl of 0.5% (v/v) dimethyl sulfoxide (DMSO), a positive control group treated with 200 microl of 100 microM piroxicam, and a test group treated with 100 microg/500 microl of CG, where the test agents were administered by injection once a week for 4 weeks starting from the third week. Rabbits were then sacrificed to observe the progression of OA-like lesion. The synovial fluid was analyzed for the amounts of total proteins, glycosaminoglycans (GAG) and prostaglandin E(2) (PGE(2)). In addition, histopathologic analyses were performed on the OA-like articular cartilage with or without therapeutic treatments. RESULTS: The total synovial fluid volume (P<0.05) was most strikingly reduced by the treatment with CG. Moreover, the CG treatment also significantly alleviated the OA-induced accumulation of prostaglandin (PG) (P<0.001) and total proteins (P<0.001) in the synovial fluid. The histopathologic analyses revealed that the CG treatment reduced the severity of the OA-like structural damages in the cartilage. However, the level of PGE(2), a pathologic inflammatory molecule, was not diminished by CG or piroxicam. CONCLUSION: These results indicate that the isoflavonoid CG isolated from AR significantly alleviated the pathologic changes in the OA-like rabbit knee joints. This suggests that CG from AR could be a promising treatment for the therapy of OA.     

Changes in serum and prostatic zinc concentrations in rats after intraprostatic injection of zinc: Comparison of two forms of zinc delivery.

BACKGROUND: We investigated changes in zinc concentrations in serum and prostatic tissue after an intraprostatic injection of zinc, and compared two forms of zinc delivery: solution and liposome. METHODS: Ninety-six male Wistar rats were used in the study (24 controls, 72 test rats). The test animals were randomly divided into two groups and were injected intraprostatically with 2 mL of 0.04 mol/L zinc sulfate according to the form of zinc delivery. Nine rats in each test group were sacrificed 1 day, 7, 14 and 28 days after injection, and 24 normal rats were injected intraprostatically with 2 mL of distilled water as controls. Serum and prostatic zinc concentrations of each group were measured by inductively coupled plasma atomic emission spectrometry. Blood chemistries, routine urinalysis, urine culture and histopathologic examination were also performed. RESULTS: Serum zinc concentrations did not change significantly after the intraprostatic injection of zinc. Prostatic zinc concentrations were found to be significantly greater (P < 0.05) in zinc-injected groups than in the control group. The intraprostatic injection of zinc solution and zinc liposome increased zinc levels in both ventral and dorsolateral lobes significantly. Prostatic zinc levels increased progressively following injection, reaching a peak level in 7 days and maintaining a high value throughout the experimental period. The prostatic zinc level of the 1-day zinc liposome group was higher than that of the 1-day zinc solution group, while no significant difference was observed between the solution and liposome group in 7, 14, 28 days. No abnormal findings were observed in any of the laboratory and histopathologic examinations; however, an acute inflammatory response was observed in the 1-day groups. CONCLUSION: These findings suggest that an intraprostatic injection of zinc in normal rats increases and maintains the prostatic zinc level for at least 4 weeks without causing any systemic or local toxicities. These findings suggest the potentially important clinical applicability of local zinc to the treatment of chronic prostatitis.     

Potentiation of apomorphine effect on sildenafil-induced penile erection in conscious rabbits

Aim: To investigate a possible potentiation effect of apomorphine (APO) on sildenafil-induced penile erection in the conscious rabbit. Methods: Erection of male New Zealand White rabbits (3.5 - 4.0 kg, n=12) was assessed by measuring the length of the uncovered penile mucosa and the duration of erection before and after intravenous administration of agents. After injection of APO (0, 0.05, 0.1 and 0.4 mg/kg), sildenafil was administered intravenously in a dose-response manner (0.5, 1 and 5 mg/kg). In additional experiments, the effect of increasing doses of sildenafil in combination with APO on systemic blood pressure was evaluated. Results: Systemic administration of sildenafil induced a dose-dependent increase in the penile length. Intravenous injection of APO alone did not produce any change in the penile length, while significantly enhanced the penile erection induced by sildenafil. The co-administration of 0.1 mg/kg of APO and 1 mg/kg of sildenafil was found to be the most effective combination in producing penile erection. Intravenous administration of sildenafil caused a concentration-dependent decrease in systemic blood pressure, but no additional decrease was observed with co-administration of APO. Conclusion: APO enhances the penile erection induced by sildenafil in the conscious rabbit without causing an additional decrease in blood pressure. (Asian J Androl 2004 Sep; 6: 205-209)     

Targeted dendrimer-based contrast agents for articular cartilage assessment by MR imaging

OBJECTIVE: Magnetic resonance (MR) imaging with contrast media has shown promise for articular cartilage assessment. Dendrimer-linked nitroxides, a new family of MR contrast agents targeted to glycosaminoglycan, may improve cartilage evaluation. This study is designed to determine the ability of dendrimer-linked nitroxides to enhance articular cartilage and measure the intra-articular life-time of these agents. DESIGN: Cartilage T(1) was evaluated using immature bovine patella in solutions of five different dendrimer-linked nitroxides, saline or Gd-DTPA at 1.5T. The "relaxivity per dose" (change in cartilage 1/T(1) produced by a given concentration of agent) was calculated. The half-life of joint fluid enhancement was measured at 2T after solutions of three dendrimer-linked nitroxides, Gd-DTPA, and saline were injected into rabbit stifle joints. Twenty-four hours after injection, the joints were examined grossly and by histology for toxicity. RESULTS: All but the largest dendrimer-linked nitroxide were able to intensely enhance articular cartilage on MR. Relaxivity per dose measurements were between 3.5 and 68 times greater than Gd-DTPA. The largest nitroxide appeared to be excluded from articular cartilage. Intra-articular half-lives of the dendrimer-linked nitroxides were sufficiently long (160-208 min) for in vivo MR imaging to be performed. Histological assessments of joints showed minimal synovial inflammatory and necrosis scores 1 day post-injection that were similar for all agents, including Gd-DTPA. CONCLUSION: Dendrimer-linked nitroxides strongly enhance cartilage and are promising as articular cartilage-specific MR contrast agents. The intra-articular life-time is sufficient for imaging studies and, in initial evaluation, the agents exhibit minimal toxicity in rabbit joints.     

Detection of aggrecanase- and MMP-generated catabolic neoepitopes in the rat iodoacetate model of cartilage degeneration

OBJECTIVE: To characterize the time course of aggrecan and type II collagen degradation in the rat iodoacetate model of cartilage degeneration in relationship to the temporal sequence that has been described in human osteoarthritis (OA). DESIGN: Rats were injected intra-articularly in one knee joint with iodoacetate and damage to the tibial plateau was assessed from digitized images captured using an image analyzer. The articular cartilage from the tibial plateau was harvested, extracted and glycosaminoglycan (GAG) content was measured using the dimethylmethylene blue (DMMB) assay. Cartilage aggrecan neoepitopes were detected in cartilage extracts by Western blotting using antibodies recognizing the aggrecanase-generated C-terminal neoepitope NITEGE (BC-13) and the MMP-generated C-terminal neoepitope DIPEN (BC-4). A type II collagen collagenase-generated neoepitope was detected in cartilage extracts by ELISA using the Col2-3/4Cshort antibody; denatured collagen was detected using the Col2-3/4m antibody. RESULTS: Degenerative joint changes and proteoglycan (GAG) loss progressed with time after iodoacetate injection. Western blotting of cartilage extracts of iodoacetate treated rats demonstrated an increase in both aggrecanase- and MMP-generated epitopes with the NITEGE aggrecanase neoepitope being significantly elevated on days 7, 14 and 21 while DIPEN the MMP neoepitope was significantly elevated on days 7 and 14. The type II collagen neoepitope recognized by Col2-3/4Cshort was significantly increased in cartilage extracts of rats at days 14 and 21 after iodoacetate injection. CONCLUSION: The proteoglycan fragments extracted from the knee cartilage of rats after the intra-articular injection of iodoacetate appeared to result from cleavage at both aggrecanase and MMP sites. Cleavage of type II collagen by collagenase was also detected after iodoacetate injection and occurred subsequent to the initiation of aggrecan loss. These observations serve to demonstrate similarities in the mechanisms of cartilage degeneration induced by iodoacetate to those seen in articular cartilage in OA.