实验动物型流行性出血热的临床特征

1983年4～8月及1990年4～5月某院实验室和动物室的工作人员中先后两次暴发了流行性出血热(EHF),病原学检查均证明实验动物大白鼠为传染源。本文对22例临床特征进行探讨。 一 流行情况 1983年某院实验室和动物室工作人员中暴发EHF的流行病学调查已有报导,大白鼠的带毒率为16.7％,大白鼠血清抗体阳性率为37.8％,

二甲双胍对2型糖尿病大鼠降脂作用的研究

目的观察二甲双胍(Met)对2型糖尿病大鼠糖代谢、脂代谢的影响,探讨其可能的作用机理。方法制备食饵性高脂2型糖尿病大鼠模型,洛伐他汀(Lov)为阳性对照药物,观察二甲双胍对2型糖尿病大鼠血糖、血脂的影响。结果与Lov组相比Met组有明显降低空腹胰岛素,改善胰岛素抵抗的作用;与DM组相比,Met及Lov均可明显降低2型糖尿病伴高血脂大鼠TC、TC、LDL-C水平,升高HDL-C水平。结论 Met可明显降低2型糖尿病伴高血脂大鼠血糖,也可明显降低空腹胰岛素水平,改善胰岛素抵抗;Met能明显改善2型糖尿病伴高血脂大鼠脂质代谢紊乱。

长春市肾综合征出血热流行趋势分析

长春市自1959年首次报告HFRS病例后,发病率曲线呈低发平稳态势波动.1998年,长春市发病呈现突发性增高趋势.随后的几年中,HFRS疫区范围不断扩大,发病率呈明显上升趋势.并先后发生多起暴发疫情及实验动物型出血热疫情,疫情发展趋势十分严峻,2005年被长春市政府列为重点防治的三大传染病之一.经过4年有效控制,疫情回落到低发地区水平.

Induction of experimental acute ulcerative colitis in rats by administration of dextran sulfate sodium at low concentration followed by intracolonic administration of 30% ethanol

Several models of experimental ulcerative colitis have been reported previously. However, none of these models showed the optimum characteristics. Although dextran sulfate sodium-induced colitis results in inflammation resembling ulcera-tive colitis, an obvious obstacle is that dextran sulfate sodium is very expensive. The aim of this study was to develop an inex-pensive model of colitis in rats. Sprague-Dawley rats were treated with 2% dextran sulfate sodium in drinking water for 3 d fol-lowed by an intracolonic administration of 30% ethanol. The administration of 2% dextran sulfate sodium followed by 30% ethanol induced significant weight loss, diarrhea and hematochezia in rats. Severe ulceration and inflammation of the distal part of rat colon were developed rapidly. Histological examination showed increased infiltration of polymorphonuclear leukocytes, lymphocytes and existence of cryptic abscesses and dysplasia. The model induced by dextran sulfate sodium at lower concentra-tion followed by 30% ethanol is characterized by a clinical course, localization of the lesions and histopathological features similar to human ulcerative colitis and fulfills the criteria set out at the beginning of this study.

Prunella vulgaris L. extract improves cellular immunity in MDR-TB challenged rats

Objective： To study the effect of the extract of Prunella vulgaris L. on multiple drugs resistant bacillus tuberculosis （MDR-TB）. Methods： Experimental animal model in rats was induced by MDR-TB. Normal group model group and Prunella vulgaris L. group were set up. The contents of IFN-7, IL-4, IL-10 and IL-12 were examined by ELISA. Their genome mRNAs were extracted, the target genes were amplified by PCR. RT-PCR was used to detect the mRNA levels of them. Results： The content of IFN-q, of the extract of Prunella vulgaris L. group was 1.98±0.67 pg/ml, IL-4 was 6.47±1.46 pg/ml, IL-10 was 12.13±3.43 pg/ml and IL-12 was 3.02±0.86 pg/ml. Compared with the model group, Prunella vulgaris L. group was notable difference in serum IFN-γ, IL-12 and IL-10 （P〈0.05）. The mRNA levels of IFN-γ, IL-12 increased and IL-10 decreased obviously, the differences were quite significant （P〈0.05）, but IL-4 had no obvious change. Conclusion： The extract of Prunella vulgaris L. can enhance the cellar immunological function in rats from up-regulation of the level of genetic transcription, accordingly provide the theory basis of healing of tuberculosis with it.

Insights into restrictive cardiomyopathy from clinical and animal studies

Cardiomyopathies are diseases that primarily affect the myocardium, leading to serious cardiac dysfunction and heart failure. Out of the three major categories of cardiomyopathies （hypertrophic, dilated and restrictive）, restrictive cardiomyopathy （RCM） is less common and also the least studied. However, the prognosis for RCM is poor as some patients dying in their childhood. The molecular mechanisms behind the disease development and progression are not very clear and the treatment of RCM is very difficult and often ineffective. In this article, we reviewed the recent progress in RCM research from the clinical studies and the translational studies done on diseased transgenic animal models. This will help for a better understanding of the mechanisms underlying the etiology and development of RCM and for the design of better treatments for the disease.

Generation of the regulatory protein rtTA transgenic mice

AIM: To translate Tet-on system into a conditional mouse model, in which hepatitis B or C virus (HBV or HCV) gene could be spatiotemporally expressed to overcome 'immune tolerance' formed during the embryonic development and 'immune escape' against hepatitis virus antigen(s), an effector mouse, carrying the reverse tetracycline-responsive transcriptional activator (rtTA) gene under the tight control of liver-specific human apoE promoter, is required to be generated. METHODS: To address this end, rtTA fragment amplified by PCR was effectively inserted into the vector of pLiv.7 containing apoE promoter to create the rtTA expressing vector, I.e., pApoE-rtTA. ApoE-rtTA transgenic fragment (-6.9 kb) released from pApoE-rtTA was transferred into mice by pronucleus injection, followed by obtaining one transgene (+) founder animal from microinjection through PCR and Southern blot analysis.RESULTS: rtTA transgene which could be transmitted to subsequent generation (F1) derived from founder was expressed in a liver-specific fashion. CONCLUSION: Taken together, these findings demonstrate that rtTA transgenic mice, in which rtTA expression is appropriately targeted to the murine liver, are successfully produced, which lays a solid foundation to 'off-on-off' regulate expression of target gene (s) (e.g., HBV and/or HCV) in transgenic mice mediated by Tet-on system.

Positively selected genes of the Chinese tree shrew （Tupaia belangeri chinensis） locomotion system

While the recent release of the Chinese tree shrew （Tupaia belangeri chinensis） genome has made the tree shrew an increasingly viable experimental animal model for biomedical research, further study of the genome may facilitate new insights into the applicability of this model. For example, though the tree shrew has a rapid rate of speed and strong jumping ability, there are limited studies on its locomotion ability. In this study we used the available Chinese tree shrew genome information and compared the evolutionary pattern of 407 locomotion system related orthologs among five mammals （human, rhesus monkey, mouse, rat and dog） and the Chinese tree shrew. Our analyses identified 29 genes with significantly high co （Ka/Ks ratio） values and 48 amino acid sites in 14 genes showed significant evidence of positive selection in the Chinese tree shrew. Some of these positively selected genes, e.g. HOXA6 （homeobox A6） and AVP （arginine vasopressin）, play important roles in muscle contraction or skeletal morphogenesis. These results provide important clues in understanding the genetic bases of locomotor adaptation in the Chinese tree shrew.

Response of meiofaunal and nematode communities to sewage pollution abatement:a field transplantation experiment

To assess the recovery rate of meiofaunal and nematode communities upon abatement of sewage pollution, a field transplantation experiment was conducted in Tat Tam, which is a non-polluted, shallow subtidal habitat on the southern portion of Hong Kong Island. The sediments used were from one site located in Victoria Harbour that was heavily influenced by sewage pollution, and one site in the outside-harbor area, which was relatively clean. In addition, sediments from Tat Tam were used as a control. Fresh sediments with meiofauna were collected from the aforementioned sites, placed in plastic trays and transplanted to Tat Tam. Sediments were retrieved at the beginning of the experiment and at 1-, 3-, and 8-weeks after transplantation for analysis of the meiofaunal and nematode communities as well as the sediment characteristics. The results showed that the meiofaunal and nematode communities in the control sediments were consistent at the four sampling periods, while it took three and eight weeks, respectively, for the nematode communities from the outside-harbor and inside-harbor sites to become similar to the control. These findings indicated that the relatively poor habitat quality and the nematode community composition in the sewage polluted inside-harbor sediments required a longer time for recovery than samples from the better habitat quality and the nematode community composition in the outside-harbor sediments.

DYNAMIC CHANGES OF SERUM VASCULAR ENDOTHELIAL GROWTH FACTOR LEVELS IN A RAT MYOCARDIAL INFARCTION MODEL

To investigate the dynamic changes of serum vascular endothelial growth factor(VEGF) levels in a rat model of acute myocardial infarction. Materials and methods.Eighty eight adult male Sprague Dawley rats weighing approximately 270 g were used in this study. Eighty rats were subjected to left coronary artery ligation, with 8 rats for each different duration of infarct. Eight sham operated animals in which the left coronary artery was surgically exposed without ligation were used as controls. Blood samples were drawn from the right atrium before (sham animals) and 1,3,6,12,24 h and 2,3,5,7,14 d after myocardial infarction. The concentrations of serum VEGF were measured by a sensitive enzyme linked immunosorbent assay with a rabbit polyclonal antibody specific for VEGF. Results. In the 8 control animals, the mean concentration of serum VEGF was 66.99±17.83 pg/ml. Six hours after myocardial infarction, the level of serum VEGF significantly increased to 125.68±28.07 pg/ml (P<0.01 vs. sham controls), and reached a peak (240.61±70.63 pg/ml. P<0.01 vs. sham animals) at 24 h after ligation and then decreased gradually over the remaining 2 weeks. However, the level remained significantly elevated for 14 d (107.64±30.13pg/ml, P<0.01 vs. sham controls). Conclusion. The present study shows that the levels of serum VEGF are markedly increased until 14 d in the rat model of acute myocardial infarction. The increased serum VEGF level may play an important role in the angiogenesis associated with myocardial infarction.

THE EFFECT OF BASIC FIBROBLAST GROWTH FACTOR SLOW-RELEASE MICROCAPSULES ON ANGIOGENESIS IN INFARCTED RABBIT MYOCARDIUM

Objectives To observe the effect of basic fibroblast growth factor (bFGF) slow-release microcapsules on angiogenesis in infarcted myocardial regions. Methods.Myocardial infarction was induced in 24 New Zealand rabbits by ligating the root of left anterior descending coronary artery.Group Ⅰ(n=8) served as control, group Ⅱ(n=8) as a blank microcapsule group, group Ⅲ(n=8, each microcapsule contains 1μg bFGF) as micrpcapsule group.In group Ⅱ and Ⅲ, 5 blank microcapsules or bFGF slow-release microcapsules were implanted into myocardium underneath the epicardium between the left anterior descending coronary artery and left circumflex artery.Infarct size was evaluated by infarcted weight/left ventricle weight ratio and angiogenesis was evaluated by immunohistochemical examinations 5 weeks later. [WT5”BX] Results.As compared with group Ⅰ and Ⅱ, rabbits treated with bFGF slow-release microcapsules showed higher microvessel counts (group Ⅰ3775±450, group Ⅱ3837±498,vs.group Ⅲ 13550±481,P<0001) and less infarcted weight /left ventricle weight (group Ⅰ168%±04%,group Ⅱ167%±05%,vs.group Ⅲ 70%±02%,P<0001). Conclusions.Subepicardial administration of bFGF slow-release microcapsule in the infarcted rabbit model results in effective angiogenesis and reduction in infarct size.

Effects of Organic Enrichment on Sandy Beach Meiofauna:A Laboratory Microcosm Experiment

Meiofauna samples from intertidal sediments of Qingdao No.2 Bathing Beach, China, were collected for field study, and subjected to organic enrichment in a laboratory microcosm experiment for 21 d. There were three different treatments including non-organic addition as the control, low-organic enrichment (2 g DW green algae per 150 mL) and high-organic enrichment (10 g DW green algae per 150 mL). After 21 d, the meiofauna richness decreased in both organic enrichment treatments. Among the three treatments, total meiofauna abundance was significantly different, and the control groups had higher abundance than the other two treatment groups. However, the responses of the meiofauna abundance in the two organic enrichment treatments were non-significantly different. The relationship of meiofaunal abundance and nematode/copepod ratios to organic matter and oxygen level in the microcosm experiments were discussed.

Dynamic action simulation system and preliminary experiments of coal seams and gas

In order to study the dynamic action and physical effects of coal seams and gas, a simulation system for this dynamic action was developed and a physical model built in our laboratory. Using this newly built model, the volume of coal outbursts and the temperature during the outburst process were studied. The results show that： l） for coal seams with similar structure and com- ponents, two factors, i.e., gas pressure and ground stress affect the volume of coal outbursts, with gas pressure being the more im- portant of the two and 2） the changes in coal temperature, both its increase and decrease, are affected by ground stress and gas pressure, it is a process of change. Preliminary tests show that the system can simulate the dynamic interaction of coal and gas, which is helpful for studying the dynamic mechanism of solid-gas coupling of gas and coal.

Modifi cation of sleep architecture in an animal model of experimental cirrhosis

AIM： To analyze the polygraphic sleep patterns during cirrhosis progression in a rat model by repeated CCh administration. METHODS： Male Wistar rats received three weekly injections of CCl4 for 11 wk, and were analyzed before and during the induction of cirrhosis. Rats were im- planted with electrodes to record their sleep patterns. Polygraph recordings were made weekly over 11 wk for 8 h, during the light period. After a basal recording, rats received three weekly injections of CCl4. Histological confirmation of cirrhosis was performed after 11 wk. RESULTS： The results showed a progressive decrease in total wake time that reached statistical significance from the second week of treatment. In addition, there was an increase in total time of slow wave sleep （SWS）Ⅱ and rapid eye movement sleep （REM sleep） in most of the 11 wk. SWS I showed no significant variations. During the final weeks, a significant increase in REM sleep frequency was also observed. Histological analyses of the livers showed unequivocal signs of cirrhosis. CONCLUSION： These data suggest that hepatic failure produced by CCh administration is capable of modifying the sleep pattern even after only a few doses.

DIFFERENCE OF REJECTION IN SINGLE VERSUS COMBINED PANCREAS AND KIDNEY TRANSPLANTATION IN RATS

Objective.To investigate the difference of rejection in single versus combined pancreas and kidney transplantation in rats. Methods.Allograft models including simultaneous pancreas and kidney(SPK)transplant and pancreas or kidney transplant alone were established in SD-Wistar rats, rejections of pancreas and kidney in different models were compared morphologically and functionally. Results.Mean survival time(MST)of pancreas was significantly prolonged in SPK than in pancreas transplant alone(PTA)(115 days vs. 92 days, P<005). Incidence of interstitial pancreatic rejection at grade Ⅱ and grade Ⅲ was much obvious in PTA than in SPK(429% vs. 125% at grade Ⅱ and 286% vs 63% at grade Ⅲ , P<005). No significant difference was found in MST between SPK and kidney transplant alone(KTA). Administration of cyclosporine A prolonged the MST of pancreas and kidney, without altering the tendency stated above. Conclusions.In SPK, the function of pancreas is protected by kidney hence the severity of rejection is reduced, whereas the function of kidney is not protected by pancreas. It suggests that different organs differ in immunoallergization and immunoregulation, and immune response tend to attack organs with greater immunoactivity, those organs with minor one could be protected. Cyclosporine A is effective on prolonging the MST of pancreas and kidney.

EFFECT OF KANGLEMYCIN C ON LYMPHOKIN A PRODUCTION AND GENE EXPRESSION OF MOUSE SPLENOCYTE AND MACROPHAGE

Aim. To study the effect of kanglemycin C (KC) on production and gene transcription of lymphokins. Methods.Cell proliferation and lymphokin activities were quantified with MTT colorimetry and ELISA, and gene transcriptions of lymphokins semi quantified with RT PCR. Results.Suppression of KC on proliferation of enriched T and B cell respectively mediated by Con A and LPS was declined by addition of exogenous IL 1, IL 2, and IL 6. KC 80 nmol/L markedly inhibited IL 2 and IL 6 production and mRNA transcription of incubated mouse splenocytes induced by Con A. Additionally, KC had some suppression on IL 1β and IL 6 productions of peritoneal macrophage stimulated by LPS (5μg/mL), whereas cyclosporine (CS) had not. [WT5”BX]Conclusion. [WT5”BZ]Immunosuppression of KC came true partially through the decrease of IL 1β, 2 and 6 productions, especially of IL 2. However, CS′s immunosuppression was mainly through the decrease of IL 2 procduction.

Kinetics of Photocatalytic Degradation of Gaseous Organic Compounds on Modified TiO_2/AC Composite Photocatalyst

This study is focused on the kinetic characteristics of photocatalytic degradation of gaseous organic compounds on modified titanium dioxide/activated carbon composite photocatalyst(MTA).The MTA,which co-doping with iron(Fe) and nitrogen(N),was synthesized by a sol-gel method,and its photocatalytic performance was investigated under different reaction conditions.The experimental data obtained were tested by the zero,first and second order kinetic model,and the factors affecting the kinetic model were analyzed.It was clearly demonstrated that the experimental data of toluene and acetone on MTA fit quite well with second order kinetic model equation,but the experimental data of formaldehyde fits well with zero order kinetic model equation.

Development and distribution of PAG-immunoreactive neurons in the central pathway of trigeminal proprioception of the rat brainstem*

Objective: To investigate the development and distribution of phosphate-activated glutaminase like immunoreactive (PAG-LI) neurons in the central pathway of trigeminal proprioception of the rat brainstem. Methods: The immunohistochemitry techniques were used. Results: (1) At embryonic day 17 (E17), PAG-LI neurons were initially observed in the mesencephalic trigeminal nucleus (Vme). All PAG-LI neurons were large round neurons with moderate immunostaining. The immunoreactivity grew intense and attained adult-like pattern at P10. (2) Not until postnatal day 10 (P10) did a few PAG-LI neurons appear in the area ven-tral to the motor trigeminal nucleus (AVM) and area dorsal to the superior olivery nucleus (ADO), and not until P12 in the dorsomedial part of the subnucleus oralis of the spinal trigeminal nucleus (Vodm) and dorso-medial part of the principal sensory trigeminal nucleus (Vpdm). As development proceeded, more and more neurons in them were immunostained, and some PAG-LI neurons were detected in the lateral reticular forma-tion adjacent to the Vodm(LRF)and the caudolateral part of the supratrigeminal nucleus (Vsup-CL) at P21. Conclusion: In the central pathway of trigeminal proprioception of the rat brainstem, PAG-LI neurons ap-peared during two stages: The first stage from E17 to P10, PAG-LI neurons appeared in the Vme and reached adult-like pattern; the second stage from P10 to P21, PAG-LI neurons appeared in the Vodm, LRF, Vpdm, Vsup-CL, ADO, AVM and gradually reached adult-like pattern. This might be relative to the estab-lishment of jaw movement patterns.

Degradation of human hair keratin scaffold material used to repair injured skeletal muscles of rabbits

Objective:To explore the mechanism of the degradation of human hair keratin (HHK) scaffold material implanted in damaged skeletal muscle tissues. Methods: Six New Zealand rabbits with HHK scaffold material implants (composed of 3 different types of HHK material with varied degradation speed) after musclectomy were divided into 3 groups (2 in each group) to observe the degradation of the material at 1, 3, 6weeks after operation. Another rabbit without operation was used as the control group. The degradation of HHK was observed with light microscopy, histochemistry of ubiquitin and electron microscopy. Results:Light microscopy showed that human hair cuticles fell off from the HHK material and emerged, and the macrophagocytes and multinucleate giant cells were attached onto the surface of the material, which became homogeneous at the first postoperative week. The HHK scaffold material was degraded into particles that was phagocytosed by macrophagocytes and multinucleate giant cells at the third week. Ubiquitin enzymatic histochemistry showed that the macrophagocytes and the multinucleate giant cells were positive at the first week. Under electron microscope, HHK scaffold material was degraded into particles, and at the sixth week,part of HHK scaffold material was further degraded. Conclusion: Large mass of the HHK scaffold material is degraded via ubiquitin system, and the resultant particles are phagocytosed and degraded with the cooperation of lysosome and ubiquitin.

EFFECT OF COXSACKIEVIRUS B3 ON ION CHANNEL CURRENTS IN RAT VENTRICULAR MYOCYTES

To investigate the effects of coxsackievirus B 3(CVB 3) on ion channel currents in rat ventricular myocytes. Methods.Rat hearts were isolated with collagenase to acquire single ventricular myocytes, L type voltage dependent calcium channel(VDCC)current (I Ca ),Na + current (I Na ), outward potassium current (I out ), inwardly rectifying potassium current(I KI ) were recorded using whole cell patch clamp techniques. ResultsCVB 3 infection increased I Ca and I out , while decreased I KI ; but it had no obvious effect on I Na . Conclusion.The effects of CVB 3 on I Ca 、 I out 、 I KI may be one of the mechanisms of myocytes damage and the occurrence of abnormal electroactivities induced by CVB 3 infection.