猴卡氏肺孢子虫肺炎模型的建立及蒿甲醚的疗效试验

从住家附近诱捕到 13只野鼠 ,经皮下注射醋酸可的松 10周 ,建立野鼠卡氏肺孢子虫肺炎模型 ,取野鼠肺组织制成接种物。 1～ 6号实验猴经气管接种 3 6× 10 6 卡氏肺孢子虫包囊 ,接种前 5d至接种后 35d注射醋酸可的松。 7～ 12号实验猴经气管接种 7 2× 10 6 卡氏肺孢子虫包囊。接种后 ,1～ 6号实验猴出现严重的临床症状 ,病理变化呈典型的卡氏肺孢子虫肺炎 ;7～ 12号实验猴为亚临床症状 ,经注射醋酸可的松后 ,则出现类似于 1～ 6号实验猴的严重症状和病理变化。实验结果表明实验猴免疫力低下时 ,接种外源性卡氏肺孢子虫包囊可导致典型的卡氏肺孢子虫肺炎 ;呈隐性感染的实验猴经免疫抑制处理后 ,亦可导致卡氏肺孢子虫肺炎。用蒿甲醚对呈卡氏肺孢子虫肺炎的实验猴进行治疗 ,取得明显的治疗效果     

犬卡氏肺孢子虫肺炎模型的建立及药物的疗效观察

在住家附近诱捕到6只褐家鼠和5只黄胸鼠，经皮下注射醋酸可的松10周，建立野鼠卡氏肺孢子虫肺炎模型，解剖取肺脏制成接种物。1-16号实验犬经气管接种6.6×105卡氏肺孢子虫包囊，并肌肉注射醋酸可的松。接种后，1-16号实验犬相继出现严重的临床症状，病理变化呈典型的卡氏肺孢子虫肺炎。实验结果表明接种外源性卡氏肺孢子虫包囊后，每犬每日肌注醋酸可有松20mg／kg，连续56天可建立实验犬卡氏肺孢子虫肺炎模型。尔后分别用蒿甲醚和复方新诺明进行治疗观察，均取得较好的治疗效果。     

实验猪卡氏肺孢子虫肺炎模型的建立及药物治疗试验

在住家及野外诱捕到4只小家鼠、8只黄胸鼠和5只褐家鼠，经皮下注射醋酸可的松10周，建立了鼠类卡氏肺孢子虫(Pneumocystiscarinii,PC)肺炎模型。取模型鼠肺脏制成鼠PC包囊接种物，给实验Ⅰ组8头猪经气管接种3.2×105个PC包囊，且接种前5d至接种后42d肌注醋酸可的松。给实验Ⅱ组8头猪经气管接种6.4×105个PC包囊。接种后，实验Ⅰ组猪均出现严重的临床症状，病理变化呈典型的PC肺炎；实验Ⅱ组猪均为亚临床症状。对实验Ⅱ组猪再注射醋酸可的松后，出现了类似于实验Ⅰ组猪的严重临床症状和病理变化。由此表明，实验猪免疫力低下时，接种外源性PC可导致典型的PC肺炎；健康实验猪接种外源性PC，则呈隐性感染，经免疫抑制剂处理后可激活病原体，导致PC肺炎。用氨苯砜-联磺甲氧苄啶对PC肺炎猪进行治疗试验，取得了较好的效果。     

建立大鼠卡氏肺孢子虫肺炎模型几种方法的对比研究

将住家附近透捕的 13只黄胸鼠、6只褐家鼠和 10只 Wistar大鼠 ,经皮下注射醋酸可的松建立野鼠和实验大鼠PCP模型。取野鼠和大鼠肺脏分别制备含 PC包囊的接种物 ( )和接种物 ( )。实验 组 15只大鼠接种接种物 ( ) ,给予皮下注射醋酸可的松 ;15只大鼠接种后不注射醋酸可的松。实验 组 15只大鼠接种接种物 ( )后注射醋酸可的松 ;15只大鼠接种后不注射。实验 、 组分别注射醋酸可的松和地塞米松。注射醋酸可的松的 、 、 组和注射地塞米松的 的大鼠先后相继出现严重的临床症状 ,病理变化呈典型的 PCP,未注射醋酸可的松 、 组大鼠发展为亚临床症状。实验结果表明 ,实验 、 组接种 PC包囊的大鼠用免疫抑制剂处理和直接应用免疫抑制剂处理的 、 组大鼠均可建立 PCP模型 ,但接种 PC包囊的大鼠比不接种 PC包囊的大鼠出现典型 PCP的时间要早 ;而接种 PC包囊不用免疫抑制剂处理的大鼠则呈隐性感染     

犬卡氏肺孢子虫实验感染及氨苯砜-联磺甲氧苄啶疗效观察

卡氏肺孢子虫（Pneumocystis carinii）是机会性感染中常见的病原体,75%艾滋病（AIDS）患者可感染卡氏肺孢子虫而出现致命的卡氏肺孢子虫肺炎,成为艾滋病的一个重要死因.除寄生于人体外,还可存在于多种动物体,当动物机体免疫力低下时,可造成动物的发病乃至死亡.本实验从一条幼犬（因发生肺炎,用抗生素治疗无效而死亡）肺组织涂片检到卡氏肺孢子虫包囊和滋养体,取肺组织分离病原体制成接种物,经气管接种实验犬,以检测犬对同源卡氏肺孢子虫的易感性.在感染成功而导致实验犬出现典型的卡氏肺孢子虫肺炎的基础上,应用氨苯砜-联磺甲氧苄啶进行疗效试验,以治疗后临床症状的恢复及肺组织、气管内的病原体消失为依据,判断其效果。     

醋酸可的松和地塞米松诱发野鼠卡氏肺孢子虫肺炎的试验研究

采用16只褐家鼠、30只黄胸鼠和20只小家鼠经皮下注射醋酸可的松和地基米松12周，建立野鼠卡氏肺孢子虫肺炎模型。经剖捡，取肺组织制备涂片、印片和切片，用不同染色液染色后，进行病原体形态观察。结果表明：黄胸鼠卡氏肺孢子虫感染率最高，为100％；褐家鼠感染率次之，为81．25％；小家鼠最低，为65％；注射醋酸可的松的诱导率高于地塞米松的诱导率。支气管灌洗液涂片和肺组织印片用姬姆萨染色后，可见卡氏肺孢子虫的囊内小体和滋养体；肺组织印片和切片用哥氏银、甲苯胺蓝染色后，可见清晰的卡氏肺孢子虫的包囊壁。     

卡氏肺孢子虫肺炎动物模型建立及病原体的形态观察

Wistar大鼠、小鼠、家兔和野生鼠用皮下注射醋酸可的松建立卡氏肺孢子虫肺炎的动物模型。解剖,取肺脏制作涂片、印片和石蜡切片,经染色进行病原体形态观察。结果显示野生鼠卡氏肺孢子虫感染率最高,为81．3％;Wistar大鼠感染率其次,为56．3％;小鼠为25％;家兔为12．5％。支气管肺泡灌洗液涂片和肺组织印片用姬姆萨染色后,可见卡氏肺孢子虫的囊内小体和滋养体。肺组织切片用哥氏银、甲苯胺蓝染色后,可见清晰的卡氏肺孢子虫的包囊壁。     

鼠类机会性寄生虫感染的实验研究

将住家附近诱捕到的74只黄胸鼠、43只褐家鼠和56只小家鼠随机分为实验Ⅱ组和对照组。实验Ⅰ组90只野鼠饮用1.0/L醋酸地塞米松水溶液；实验Ⅱ组66只野鼠给予皮下注射醋酸可的松；对照组不作任何处理。结果从实验Ⅰ组和实验II组的野鼠粪便和各种组织内共分离出5种机会性寄生虫，即微小隐孢子虫，结肠小袋纤毛虫，溶组织内阿米巴，弓形虫和卡氏肺孢子虫。然后将分离的虫体分别制成接种物，接种各种实验动物。接种后.经免疫处理的实验动物均出现典型的临床症状或死亡；未经免疫处理的实验动物则呈隐性感染。结果证明在机体免疫功能低下时.实验动物接种机会性病体后均能获得感染。提示我们，鼠类机会性寄生虫可能成为人体和其他动物感染的传染源，在公共卫生学上有重要意义。     

免疫缺陷疾病同时并发卡氏肺孢子虫和隐孢子虫动物模型建立

实验组普通级ＳＤ大鼠皮下注射醋酸可的松，２５ｍｇ／次／只，每周２次。４周后，每隔２周剖杀６只，检查卡氏肺孢子虫和隐孢子虫的感染强度和感染率。结果，第１２周卡氏肺孢了虫和隐孢子虫的合并并发率达１００％。     

双氢青蒿素治疗大鼠卡氏肺孢子虫肺炎后的肺脏病理变化观察

为研究经双氢青蒿素治疗后卡氏肺孢子虫肺炎 (PCP)大鼠肺部病理学变化 ,以地塞米松磷酸钠皮下注射 Wistar大鼠建立卡氏肺孢子虫肺炎动物模型 ,用 60 mg/ kg双氢青蒿素治疗实验大鼠 ,杀鼠取肺 ,用光镜和电镜观察肺部病理学变化 ,同时设有感染对照组和正常对照组。结果发现肺印片中卡氏肺孢子虫 (Pc)包囊数目显著减少 ,肺组织炎症明显减轻 ,Pc滋养体表膜和核膜破裂 ,胞质中出现大量空泡和高电子密度颗粒 ,Pc包囊中也出现空泡 ,囊内小体变性坏死。研究结果表明双氢青蒿素可杀死 Pc滋养体和包囊 ,从而减轻肺组织的炎症反应     

Neosporosis in cats

Six cats (Nos. 1-6) were inoculated intramuscularly with (1 x 10(6)) and orally (5 x 10(5)) tachyzoites of Neospora caninum. Three (Nos. 1-3) of the six cats were given 40 mg/kg methylprednisolone acetate 7 days before and on the day of inoculation with N. caninum tachyzoites, and three cats (Nos. 4-6) were not given methylprednisolone acetate. Two of the cats (cat Nos. 1 and 2) given methylprednisolone acetate died suddenly. Cat No. 1 died 8 days post-inoculation, and cat No. 2 died 16 days post-inoculation. Cat No. 3 was euthanatized 21 days post-inoculation. Cat No. 1 had lesions of gram-positive bacterial septicemia. Necrotizing encephalitis, myelitis, disseminated skeletal muscle necrosis, hepatic necrosis, interstitial pneumonia, and renal tubular necrosis were the main lesions in cat Nos. 2 and 3. The cats that were not given methylprednisolone acetate remained clinically normal except for slight weight loss in cat No. 6. All three of these cats were euthanatized 55 days post-inoculation. Mild myositis and encephalitis were noted on microscopic examination of tissues from these three cats. Neuromuscular lesions were not seen in six control cats (Nos. 7-12) not inoculated with N. caninum and euthanatized 21 or 22 days after administration of the first two doses of methylprednisolone acetate (40 mg/kg), given at a weekly interval.     

Efficacy of acyclovir against herpesvirus infection in Quaker parakeets.

We evaluated the efficacy of acyclovir against experimentally induced herpesvirus infection (Pacheco's parrot disease) in Quaker parakeets. Thirty-two of 40 birds were challenge-exposed with 0.1 ml of a suspension of herpesvirus (10(4) median cell culture infective doses [CCID50]) given IM. Treatment with acyclovir was started 24 hours later and was continued for 7 days. The birds were allotted to 5 groups of 8 birds each. There was a considerable difference in mortality between groups 1-5. Of 8 bird in each group, 6 died in group 1 (control), 1 died in group 2 (gavage), 3 died in group 3 (low dose, IM), 4 died in group 4 (high dose, IM), and none died in group 5 (contact controls). There was a significant (P = 0.023) difference in mortality between groups 1 and 2, thus the oral form of acyclovir administered by gavage was the most efficacious therapeutic regimen. Clinical signs and death occurred after discontinuation of acyclovir in groups 2 and 3, whereas the mean time of death for the control group was 6 days after challenge exposure. Herpesvirus was recovered by inoculation of chick embryo cell culture with pooled tissue suspensions from all birds that died. Histologic evidence of herpesvirus infection was found in most birds that died, with the control group having the most severe lesions. Surviving Quaker parakeets were transferred to cages with seronegative Quaker parakeets with no known exposure to herpesvirus. There have been no deaths attributable to herpesvirus infection in a period exceeding 2 years.     

Experimental infection of chickens, ducks and quails with the highly pathogenic H5N1 avian influenza virus

Highly pathogenic avian influenza viruses (HPAIV) of the H5N1 subtype have spread since 2003 in poultry and wild birds in Asia, Europe and Africa. In Korea, the highly pathogenic H5N1 avian influenza outbreaks took place in 2003/2004, 2006/2007 and 2008. As the 2006/2007 isolates differ phylogenetically from the 2003/2004 isolates, we assessed the clinical responses of chickens, ducks and quails to intranasal inoculation of the 2006/2007 index case virus, A/chicken/Korea/IS/06. All the chickens and quails died on 3 days and 3-6 days post-inoculation (DPI), respectively, whilst the ducks only showed signs of mild depression. The uninoculated chickens and quails placed soon after with the inoculated flock died on 5.3 and 7.5 DPI, respectively. Both oropharyngeal and cloacal swabs were taken for all three species during various time intervals after inoculation. It was found that oropharyngeal swabs showed higher viral titers than in cloacal swabs applicable to all three avian species. The chickens and quails shed the virus until they died (up to 3 to 6 days after inoculation, respectively) whilst the ducks shed the virus on 2-4 DPI. The postmortem tissues collected from the chickens and quails on day 3 and days 4-5 and from clinically normal ducks that were euthanized on day 4 contained the virus. However, the ducks had significantly lower viral titers than the chickens or quails. Thus, the three avian species varied significantly in their clinical signs, mortality, tissue virus titers, and duration of virus shedding. Our observations suggest that duck and quail farms should be monitored particularly closely for the presence of HPAIV so that further virus transmission to other avian or mammalian hosts can be prevented.     

Hyaluronic acid in synovial fluid. VI. Effect of intra-articular injection of hyaluronic acid on the clinical symptoms of arthritis in track horses

Twelve horses with traumatic arthritis were treated with intraarticular injection of hyaluronic acid mixed with cortisone and the results compared with 6 horses treated only with cortisone. There was a significantly better improvement in the group injected with a mixture of hyaluronic acid and cortisone. Further studies have given the same results in traumatic arthritis in horses if hyaluronic acid alone is injected.After injection of hyaluronic acid a large number of granulated monocytes appeared in the synovial fluid, but no inflammatory signs were observed. It is possible that this macrophage invasion is instrumental in producing improvement in the condition of the joint. The injected hyaluronic acid may also adhere to the surface of articular cartilage producing an “clastic cushion” protecting the cartilage surface.Experimental mechanical damage was also inflicted on the surface of articular cartilage in dogs and monkeys, and smoother healing was achieved if hyaluronic acid was injected into the joints after the damage.Injections of hyaluronic acid seem to be of value in treating traumatic arthritis or similar conditions.     

An experimental model for subclinical edema disease (Escherichia coli enterotoxemia) manifest as vascular necrosis in pigs.

An experimental model for subclinical edema disease was developed in weanling pigs. In multiple experiments, 3-week-old pigs were weaned, then inoculated intragastrically with 10(10) colony-forming units of an SLT-IIv-positive strain of Escherichia coli originally isolated from a pig with edema disease (principals). Control pigs were inoculated with a nonpathogenic E coli strain. Of 39 principals, 8 developed clinical edema disease within 14 days after inoculation. However, 20 of 21 principals that did not develop clinical signs of edema disease, but were submitted for necropsy examination at 14 days after inoculation, had characteristic vascular lesions of edema disease. Vascular lesions, found principally in ileum and brain, consisted of segmental necrosis of myocytes in the tunica media of small arteries and arterioles. None of the pigs inoculated with a nonpathogenic strain of E coli developed edema disease or vascular lesions. None of the principals necropsied at 2 days after inoculation had vascular lesions. Development of vascular lesions by 14 days after inoculation was used as the end point for detecting subclinical edema disease in the model.     

Evaluation of a live avirulent Escherichia coli vaccine for K88+, LT+ enterotoxigenic colibacillosis in weaned pigs.

Live, avirulent Escherichia coli vaccine strains were constructed and tested for efficacy in preventing colibacillosis in 4-week-old pigs. Either or both of 2 plasmids were inserted into avirulent E coli strain G58-1 (0101:NM). These plasmids were pPMC4, which encodes for LTb subunits of heat-labile enterotoxin, and pDHF1, which encodes for K88ac fimbriae. Litter- and weight-matched pigs were removed from sows when they were 10 days old and vaccinated orally with the constructed strains or with G58-1 (negative control vaccine) when they were 2 weeks old and 5 days later. All pigs were challenge-inoculated with virulent E coli strain 3030-2 (O157:K88, LT+, STb+) 2 weeks after the first vaccination. Only 1 pig vaccinated with G58-1/pPMC4/pDHF1 developed diarrhea and none died following challenge inoculation. Seventeen of 31 control pigs developed diarrhea and 11 died. Of 18 pigs vaccinated with G58-1/pDHF1 then challenge-inoculated with the virulent strain, 5 developed diarrhea and 2 died. Fifteen of 18 litter- and weight-matched controls developed diarrhea and 8 died. When compared with G58-1 (negative control), G58-1/pPMC4 afforded no protection to pigs challenge-inoculated with 3030-2.     

Confirmation that the dog is a definitive host for Neospora caninum.

Two mixed-breed littermate dogs were fed mouse brains containing tissue cysts of the NC-beef isolate of Neospora caninum. Both dogs excreted N. caninum oocysts in their feces. Dog 1 which was given methylprednisolone acetate (MPA) prior to ingesting tissue cysts, excreted oocysts on days 5 to 10 inclusive and on day 17 after ingesting tissue cysts. Dog 1 had a serum antibody titer of 1:200 in the indirect fluorescent antibody test (IFAT) 35 days after it was fed tissue cysts. Dog 2, which was not treated with MPA, excreted oocysts on Day 6 and Day 9 after ingesting tissue cysts. Antibodies to N. caninum were not found in a 1:25 dilution of serum on any examination period for Dog 2 during the study. Neospora caninum was not found in the tissues of either dog by histological or immunohistochemical means following necropsy 42 days after being fed tissue cysts. The identity of the oocysts excreted in the feces of the dogs was confirmed by mouse inoculation studies.