The long non-coding RNA DDX11-AS1 facilitates cell progression and oxaliplatin resistance via regulating miR-326/IRS1 axis in gastric cancer.

OBJECTIVE: The long non-coding RNA DDX11 antisense RNA 1 (DDX11-AS1) was found to be highly expressed in gastric cancer (GC). This study was to explore the role and molecular mechanism in oxaliplatin (OXA) resistance. PATIENTS AND METHODS: The levels of DDX11-AS1, microRNA-326 (miR-326) and insulin receptor substrate 1 (IRS1) were measured by quantitative Real-time polymerase chain reaction (qRT-PCR). Cell proliferation, migration, invasion and apoptosis were examined by methylthiazolyldiphenyl-tetrazolium bromide (MTT), transwell and flow cytometry assays, respectively. Levels of all protein were detected using Western blot. The correlation between miR-326 and DDX11-AS1/IRS1 was confirmed by Dual-Luciferase reporter and RNA immunoprecipitation (RIP) assays. The xenograft model was constructed to explore the effect of DDX11-AS1 in vivo. RESULTS: DDX11-AS1 was overexpressed in OXA-resistant GC tissues and cells, and DDX11-AS1 knockdown inhibited cell proliferation, migration, invasion and OXA resistance, and promoted apoptosis in OXA-resistant GC cells. Mechanically, DDX11-AS1 directly targeted miR-326 and miR-326 could bind to IRS1 in OXA-resistant GC cells. Functionally, silencing DDX11-AS1 repressed the progression and OXA resistance in OXA-resistant GC cells by down-modulating IRS1 expression via sponging miR-326 in vitro and in vivo. CONCLUSIONS: DDX11-AS1 accelerated the progression and OXA chemoresistance of GC cells in vitro and in vivo by sponging miR-326, thus increasing the expression of IRS1, suggesting DDX11-AS1 might be a promising prognostic biomarker and therapeutic target in GC.

Clinicopathologic risk factors for right paraesophageal lymph node metastasis in patients with papillary thyroid carcinoma.

OBJECTIVES: To investigate risk factors associated with right paraesophageal lymph node (RPELN) metastasis in patients with papillary thyroid carcinoma (PTC) and to determine the indications for right lymph node dissection. METHODS: Clinicopathologic data from 829 patients (104 men and 725 women) with PTC, operated on by the same thyroid surgery team at the First Affiliated Hospital of Harbin Medical University from January 2013 to May 2017, were analyzed. Overall, 309 patients underwent total thyroidectomy with bilateral lymph node dissection, 488 underwent right thyroid lobe and isthmic resection with right central compartment lymph node dissection, and 32 underwent near-total thyroidectomy (ipsilateral thyroid lobectomy with contralateral near-total lobectomy) with bilateral lymph node dissection. RESULTS: The overall rate of central compartment lymph node metastasis was 43.5% (361/829), with right central compartment lymph node and RPELN metastasis rates of 35.5% (294/829) and 19.1% (158/829), respectively. Tumor size, number, invasion, and location, lymph node metastasis, right central compartment lymph node metastasis, and right lateral compartment lymph node metastasis were associated with RPELN in the univariate analysis, whereas age and sex were not. Multivariate analysis identified tumors with a diameter ≥ 1 cm, multiple tumors, tumors located in the right lobe, right central compartment lymph node metastasis, and right lateral compartment lymph node metastasis as independent risk factors for RPELN metastasis. CONCLUSIONS: Lymph node dissection, including RPELN dissection, should be performed for patients with PTC with a tumor diameter ≥ 1 cm, multiple tumors, right-lobe tumors, right central compartment lymph node metastasis, or suspected lateral compartment lymph node metastasis.

Predictive values of FAP and HGF for tumor angiogenesis and metastasis in colorectal cancer.

This study aims to explore the correlation of hepatocyte growth factor (HGF) and fibroblast activation protein (FAP) expressions with the angiogenesis and metastasis in colorectal cancer (CRC). The immunohistochemical SABC method was used to detect HGF and FAP expressions in 127 CRC tissues, 51 colorectal polyp tissues and 28 normal tissues. HGF and FAP expressions in liver metastasis were detected using western blot to analyze the correlation of their expressions with lymph node metastasis and liver metastasis. Micro-vessel density (MVD) and clinic-pathologic information of CRC patients were recorded and analyzed. In CRC group, HGF and FAP expressions were greatly higher than those in normal group and colorectal polyps group (P < 0.05). Moreover, the positive rates of HGF and FAP expressions in lymph node metastasis were evidently higher than those in non-lymph node metastasis (P < 0.05). In liver metastasis group, HGF and FAP expressions were obviously higher than non-liver metastasis group (P < 0.05). CRC group had much more MVD in comparison with normal group and colorectal polyps group (P < 0.05).When compared with negative group, MVD was significantly higher than that in CRC tissue with positive HGF and FAP (P < 0.05). Spearman rank correlation analysis showed that HGF and FAP were in positive correlation with MVD (r = 0.542, P < 0.001; r = 0.753, P < 0.001). These results indicate that FAP and HGF play an important role in CRC angiogenesis, and their expression levels are valuable to predict CRC liver metastasis and lymph node metastasis.

[Study of epidemic area on Tsutsugamushi disease in Taizhou from 2013 to 2014].

Objective: To study the epidemiological characteristics of tsutsugamushi disease, and to confirm the existence of the disease's epidemic foci in Taizhou. Methods: From 2013 to 2014, Dongxing town hospital and Xingqiao town hospital were selected as specimen collection sites in Jingjiang city. Blood samples (5 ml) were collected from 40 patients with acute tsutsugamushi disease. A total of 59 rodents were captured with cage night method in the survey sites at 5, 7, 9, 10, and 11 months in 2013, from which, the spleen, liver, and kidney specimens were selected. Chigger mites were captured by small blackboard method and from the ears of the captured rodents. A total of 226 small blackboards were laid, 27 mites were captured, and the samples were grounded into suspension. Nested-polymerase chain reaction and cell and tissue culture techniques were used to test the specimen from the probable patients, host animals and chigger mites. Results: Among the 40 acute tsutsugamushi disease blood samples, 29 were found to meet the test requirements, 17 were positive for orientia tsutsugamushi nucleic acid with 59% of the positive rate, and 1 stran orientia tsutsugamushi was isolated. 59 rats were captured and the density of mice was 5.5%. Among them, there were 26 Mus musculus (2.4%), 18 Rattus flavipectus (1.7%) and 15 Smelly shrew (density 1.4%). 1 Smelly shrew was tested positive for orientia tsutsugamushi nucleic acid, and the negative results were found in the other rodent specimens. 27 Chigge mites were collected by small blackboard method and the density of mites was 0.12 for each blackboard, among which 3 larvae and 24 nymphs were found. 33 Chigger mites were collected from the ears of 3 Smelly shrew, and the density of the mite was 11 per mouse. All the captured Chigger mites were identified as Leptotrombidium scutellare and 1 group of specimens of Chigger mites from the external environment were positive for orientia tsutsugamushi nucleic acid. Conclusion: There was a high density of mice in the epidemic area from May to November and the species of the chigger mites were Chigger mites in Taizhou. The nucleic acid of the oriental tsutsugamushi was detected in the patients with acute scrub typhus, rodents and vectors. According to the above-mentioned results, it was considered that the scrub typhus epidemic area of Taizhou city has the natural foci of scrub typhus.

[Application of directed acyclic graphs in control of confounding].

Observational study is a method most commonly used in the etiology study of epidemiology, but confounders, always distort the true causality between exposure and outcome when local inferencing. In order to eliminate these confounding, the determining of variables which need to be adjusted become a key issue. Directed acyclic graph(DAG)could visualize complex causality, provide a simple and intuitive way to identify the confounding, and convert it into the finding of the minimal sufficient adjustment for the control of confounding. On the one hand, directed acyclic graph can choose less variables, which increase statistical efficiency of the analysis. On the other hand, it could help avoiding variables that is not measured or with missing values. In a word, the directed acyclic graph could facilitate the reveal of the real causality effectively.

Preclinical study on induction of pluripotent stem cells from urine of dilated cardiomyopathy patients.

OBJECTIVE: Dilated cardiomyopathy (DCM) is featured by left or bilateral ventricular dilation combined with systolic dysfunction. Its clinical manifestations include heart enlargement, cardiac failure, arrhythmia and cardiac arrest. Medication and heart transplantation have but only limited treatment effect on DCM. MATERIALS AND METHODS: Induced pluripotent stem cell (iPSC) treatment provides a new solution for DCM treatment. Human renal epithelial cells were extracted from the urine of patients with DCM and transfected with Sendai virus carrying OCT3/4, Sox2, Klf4 and c-Myc gene to generate iPSCs by reprogramming. RESULTS: The morphology and pluripotency of iPSCs obtained from the renal epithelial cells from patients with DCM were confirmed, as well as the growth characteristics, immunohistochemical features and surface markers of embryonic stem cells. Teratoma was formed in vivo. CONCLUSIONS: We demonstrated that it was feasible to obtain iPSCs from the urine of patients with DCM. This technique lays down the cytological foundation for understanding the pathogenesis and for drug screening and gene therapy for DCM.

[Influence of social support and coping style on chronic post-traumatic stress disorder after floods].

OBJECTIVE: To explore the long-term prognosis and influence of social support and coping style of patients with post-traumatic stress disorder (PTSD) after suffering from floods. METHODS: Patients suffered PTSD due to Dongting lake flood in 1998 were selected through cluster random sampling. PTSD scale civilian version (PCL-C) was used to examine and diagnose the participants in this study. PTSD was then evaluated by the social support rating scale (SSRS) and the simple coping style questionnaire (SCSQ). RESULTS: Among all the 120 subjects, 14(11.67%) of them were diagnosed as having PTSD. Compared with the rehabilitation group, scores on subjective support, objective support, total social support and positive coping, total of coping style from the non-rehabilitation group all appeared significant low (P<0.05). Data from the multivariate logistic regression showed that social support (OR=0.281, 95% CI: 0.117-0.678) and coping style (OR= 0.293, 95% CI: 0.128-0.672) were protective factors of the chronic PTSD after the floods while disaster experience (OR=1.626, 95%CI: 1.118-2.365) appeared as a risk factor. CONCLUSION: Chronic PTSD developed after the floods called for attention. Better social support, positive coping style could significantly improve the long-term prognosis of patients with PTSD after the floods.

Efficacy of standard dose rituximab for refractory idiopathic thrombocytopenic purpura in children.

OBJECTIVE: The present study intends to investigate the efficacy and safety of standard dose rituximab for treatment of refractory idiopathic thrombocytopenic purpura (RITP) in children. PATIENTS AND METHODS: A total of 50 cases of children hospitalized with RITP in a hospital were enrolled in this study, and randomly divided into two treatment groups according to the therapeutic methods: rituximab group (n = 26) and vincristine group (n = 24). Another 20 healthy children receiving physical examination in the hospital during the corresponding period were enrolled as the control group. Before treatment the thrombocytes were counted with hematology analyzer and the CD19+/CD20+ B cells in peripheral blood tested with flow cytometry in rituximab group. Then the children in the rituximab group were given standard dose rituximab at 375 mg/m2 via four weekly intravenous drip, while those in vincristine group treated with vincristine at 0.02 mg/kg by intravenous drip once a week for three months. During the treatment the adverse drug reactions were observed and recorded. After the treatment, the efficacy of two drugs was each evaluated, and the thrombocytes and CD19+/CD20+ B cells in peripheral blood of rituximab group were quantified in the same way, and the children in both treatment groups were followed up and the recurrence rate recorded. RESULTS: The total efficiency including complete response and partial response in rituximab group was significantly higher than that in vincristine group (69.2% vs. 37.5%, χ2 = 9.74, p < 0.01). The prevalence rates of adverse reactions were statistically indifferent between two treatment groups during the therapy (11.5% vs. 8.3%, χ2 = 0.62, p > 0.05). The follow-up visit showed that the recurrence rate of rituximab group including those showing complete response and partial response was significantly lower than that of vincristine group (22.2% vs. 55.6%, χ2 = 7.24, p < 0.05). The peripheral blood platelet number of children showing complete response and partial response in group of rituximab was 106.7 ± 32.5 × 109/L after treatment and significantly higher compared with that before treatment (t = 12.48, p < 0.01). The amount of CD19+/CD20+ B cells in peripheral blood of rituximab group after treatment was significantly lower than that before treatment (t = 6.71, p > 0.05). CONCLUSIONS: Rituximab may play a role in the efficacy by depleting B cells and can cure RITP in children without causing serious adverse reactions.

Significance of lipopolysaccharide detection in children with pulmonary infections.

OBJECTIVE: The present study aimed to observe the alterations of lipopolysaccharide (LPS) and some other laboratory indexes in children suffering from pulmonary infections, and to investigate the condition of Gram-negative bacterial infection. PATIENTS AND METHODS: All the patients received routine blood test, C reactive protein (CRP), erythrocyte sedimentation rate (ESR), Mycoplasma pneumoniae antibody IgM (MP-IgM), LPS, blood culture and chest X-ray examination. The clinical data was collected followed by induction arrangement and statistical analysis. RESULTS: In terms of the rate of abnormity in peripheral white blood cell count and positive rate of blood CRP, no significant difference was found between children with pulmonary infections and the healthy individual in the control group (p > 0.05). The positive rates of blood MP-IgM were 33.33% and 32.26% in children with different progressive stages of pulmonary infections, which were significantly lower than those in the control group (62.96%) (p < 0.05). The positive rates of blood LPS in the observation group were higher than those in the control group, especially for those children at progressive stages within one week; and the difference between them was significant (p < 0.05). With regard to blood bacterial culture, the positive rates were 9.52% and 29.03% for children in progressive stages within one week and over one week in the observation group, respectively; the latter was significantly higher than that in the control group (p < 0.05). The result of the correlation analysis suggested a weak correlation between the positive rate of increased blood LPS in the observation group and that in blood bacterial culture (χ2 = 6.61, p < 0.05; Pearson's contingency coefficient C = 0.34). However, there was no significant correlation between the positive rate of increased blood LPS and peripheral blood white cell count, CRP, or MP-IgM (p > 0.05). CONCLUSIONS: Endotoxemia is often accompanied by pulmonary infections, and gram-negative bacterium is a common pathogenic bacterium in children with different progressive stages of pneumonia.

Mucosal immunization with PsaA protein, using chitosan as a delivery system, increases protection against acute otitis media and invasive infection by Streptococcus pneumoniae.

As infection with Streptococcus pneumoniae (mainly via the mucosal route) is a leading cause of acute otitis media, sinus and bacterial pneumonia, the mucosal immunity plays an important role in the prevention of pneumococcal diseases. Therefore, intranasal vaccination may be an effective immunization strategy, but requires appropriate mucosal vaccine delivery systems. In this work, chitosan was used as a mucosal delivery system to form chitosan-PsaA nanoparticles based on ionotropic gelation methods and used to immunize BALB/c mice intranasally. Compared to mice immunized with naked PsaA, levels of IFN-γ, IL-17A and IL-4 in spleen lymphocytes, the systemic (IgG in serum) and mucosal (IgA in mucosal lavage) specific antibodies were enhanced significantly in mice inoculated with chitosan-PsaA. Furthermore, increased protection against acute otitis media following middle ear challenge with pneumococcus serotype 14, and improved survival following intraperitoneal challenge with pneumococcus serotype 3 or serotype 14, was found in the mice immunized with chitosan-PsaA nanoparticles. Thus, intranasal immunization with chitosan-PsaA can successfully induce mucosal and systemic immune responses and increase protection against pneumococcal acute otitis media and invasive infections. Hence, intranasal immunization with PsaA protein, based on chitosan as a delivery system, is an efficient immunization strategy for preventing pneumococcal infections.

Monocyte/macrophage ß2-AR as a target of antisympathetic excitation-induced atherosclerotic progression.

The aim of this study was to determine whether monocyte/macrophage ß2-AR could act as the therapeutic target of antisympathetic excitation-induced atherosclerotic progression. Cultivated human THP-1 cells were divided into different groups and incubated with isoprenaline, metoprolol, propranolol or ß2-AR blocker for 24 h, together with oxidized low-density lipoprotein (ox-LDL). Afterwards, each group was analyzed for C-C chemokine receptor type 2 (CCR2) expression, monocyte chemotactic protein 1 (MCP-1) release into medium and cell migration ability. In the isoprenaline group, CCR2 protein level was increased, as well as the secretion of MCP-1, and cell motility was enhanced, in a concentration-dependent manner. Propranolol and ICI 118,551 significantly reversed the stimulatory effect of isoprenaline on THP-1 cells induced by ox-LDL, but only high concentrations of metoprolol interfered significantly with the action of isoprenaline (P < 0.05). Isoprenaline or a ß-AR blocker could mediate through ß2-AR, affecting MCP-1 secretion, CCR2 protein expression and cell migration capacity of THP-1 cells. Therefore, monocyte-macrophage ß2-AR may act as a target of antisympathetic excitation-induced atherosclerotic progression.

Pretreatment with bilirubin protects islet against oxidative injury during isolation and purification.

BACKGROUND: A high yield of pure, viable islets is one of the most important prerequisites for successful islet transplantation. However, during isolation and purification, many factors may cause oxidative stress, impacting islet viability. Accumulating evidence indicates that bilirubin (BR) not only has antioxidative but also has cytoprotective activities. In this study, we investigated whether pretreatment with bilirubin would protect islets against oxidative damage during isolation and purification. METHODS: Wistar rats were randomly divided into control and BR groups. The latter rats received an injection of BR 2 hours before islet isolation, whereas the controls received vehicle. Islet purity was determined using a dithizone stain. Survival rate and viability were determined using acridine orange and propidium iodide staining and the Cell Counting Kit-8 Kit. Islet function was quantified by testing glucose-stimulated insulin secretion. Islet damage caused by oxidative stress was quantified by measuring the malondialdehyde (MDA) in freshly isolated islets. RESULTS: Pretreatment with bilirubin did not enhance the purity, but significantly enhanced the survival rate and viability of the islets. Islet function in the BR group was significantly better than that in the control cohort. The MDA level was 0.62 ± 0.23 nmol/L/µg protein in the BR group, which was significantly lower (P < .05) than that in controls (1.31 ± 0.34 nmol/L/µg protein). CONCLUSIONS: We concluded that oxidative stress during islet isolation and purification can be mitigated by BR pretreatment. BR exerts antioxidant and cytoprotective properties by reducing lipid peroxidation (MDA) and enhancing islet viability and function. Pretreatment with BR may become a simple, clinical applicable means to improve human islet isolation and transplantation outcomes.

A novel HLA-DPA1*0204 allele was identified in a Chinese individual.

We report here the identification of a novel human leukocyte antigen-DPA1*0204 allele that was detected by polymerase chain reaction sequence-based typing.

Ten-year experience with living related donated splenic transplantation for the treatment of hemophilia A.

AIM: Six cases of hemophilia A treated with living related donated splenic transplantation (LRDST) were performed over 10 years. METHODS: We reviewed the six consecutive cases of LRDST from 1992 to 2002. Three patients received whole spleen allografts and the other three, partial spleen allografts. All allografts were transplanted to the extraperitoneal space in the right iliac fossa by an end-to-end anastomosis between the splenic artery and the internal iliac artery and an end-to-side anastomosis between the splenic vein and the external (or common) iliac vein. After the operation, a combined regimen with cyclosporine, azathioprine, anti-lymphocyte globulin, OKT3, was administered to suppress the immune reaction. RESULTS: The functional period of the allografts varied between 30 days to 4 years. Patient factor-VIII (F-VIII) levels rose from less than 5% before operation to 15% to 56% postoperatively. One patient died from central nervous system complications. Another lost his graft because exogenous F-VIII was not supplemented in timely fashion at the onset of rejection. And the third could no longer afford the expensive immunosuppressive drugs at 2 years after the operation and eventually lost the spleen. The remaining three patients presently have regained self-support, among whom one has survived for 4 years. CONCLUSION: Though the sample pool is relatively small, our clinical observations tend to confirm LRDST as a feasible, effective treatment for hemophilia A.

Peptide vaccines against hepatitis B virus: from animal model to human studies.

An estimated 400 million people are chronically infected with the hepatitis B virus (HBV). Chronic viral hepatitis infection incurs serious sequelae such as liver cirrhosis and hepatocellular carcinoma. Prevention and treatment, thus, represent an important target for public health. Preventive vaccines using HBsAg alone or combined with other antigens allow for the generation of neutralizing antibodies which effectively prevent infection in immunocompetent individuals. Cell-mediated immunological mechanisms are thought to be crucial in determining viral persistence or viral elimination. Therapeutic approaches aiming to shift cellular immunity towards viral elimination have been on the research agenda for many years. This paper summarizes pre-clinical and clinical results obtained with the use of immunogenic peptides formulated as vaccines to selectively boost cellular immune responses. Such vaccines are capable of generating cellular immune responses in animal models as well as in humans and represent an important step towards the development of a therapeutic vaccine against chronic hepatitis.

Perspectives: towards a peptide-based vaccine against hepatitis C virus.

Hepatitis C virus (HCV) is a widespread infectious disease in humans with the negative implication of becoming chronic in most persons. Patients infected with HCV are at risk of liver cirrhosis or hepatocellular carcinoma at later stages. In contrast to hepatitis A and hepatitis B, there is no immunization yet available, neither prophylactic nor therapeutic. Thus, there is an urgent need to develop a safe, protective vaccine against this fatal disease. Developing countries are even more at risk for HCV. There are currently a number of scientific approaches aimed towards solving this problem. Taking both risks and costs of immunization into consideration, a peptide-based vaccine may be a reasonable prophylactic protection. Also, it might be of therapeutic use in already infected patients by increasing a specific CTL response against HCV. In our lab, we are focusing on immunopotentiating reconstituted influenza virosomes (IRIVs) as carriers for immunogenic HLA-A2-restricted core epitopes to induce peptide-specific cytotoxic T lymphocytes (CTLs). The IRIVs are similar to liposomes, but in addition contain influenza-derived hemagglutinin and neuraminidase on their outer surface which makes them fusogenic, thus, permitting antigen delivery to host cells. So far, virosomes have been successfully used for vaccine development and as a result a virosomal vaccine against both influenza virus (Inflexal) BERNA) and hepatitis A virus (HAV) (Epaxal) BERNA) already exist on the market. This paper focuses on the importance of development of a successful vaccine against HCV and, more specifically, we discuss the use, advantages and disadvantages of a peptide-based vaccine. A brief report of our latest findings will be included.

Major carbohydrate antigen of Echinococcus multilocularis induces an immunoglobulin G response independent of alphabeta+ CD4+ T cells.

Echinococcus multilocularis causes alveolar echinococcosis, one of the most lethal helminthic (accidental) infections in humans, as the life cycle predominantly includes wildlife rodents as intermediate hosts. The physical barrier between the proliferating parasitic metacestode and the host tissue is the acellular laminated layer (LL), which is characterized by its rich high-molecular-weight polysaccharide composition. Conversely to a crude protein-rich vesicular fluid antigen, a major carbohydrate antigen of the LL--the Em2(G11) antigen--did not stimulate murine T-cell proliferation in vitro. In fact, the persistent metacestode growth and antigenic stimulation induced a Th2 shift in vivo following conventional infection by intraperitoneal inoculation of 100 metacestode vesicles into C57/BL6 mice. Concurrently, the expression of Th1 cytokines (interleukin-2 and gamma interferon) remained persistently low until the late stage of chronic infection. In comparison to a recombinant proteinic II/3 antigen, the specific immunoglobulin G (IgG) response against the Em2(G11) antigen (including all IgG isotypes) maintained persistently low avidity. Furthermore, the Em2(G11) antigen induced a specific IgM and IgG response in T-cell-deficient athymic nude, TCRbeta(-/-), major histocompatibility complex class II (MHCII)(-/-)(CD4-deficient), and CD40(-/-) mice. The Em2(G11)-specific IgG synthesized in nude TCRbeta(-/-) and MHCII(-/-) mice was predominantly of the IgG3 and IgG2a isotypes and of the IgG3 and IgG2b isotypes in CD40(-/-) mice. This finding suggested that in vivo, the IgG response to major carbohydrate antigen Em2(G11) of E. multilocularis could take place independently of alphabeta+ CD4+ T cells and in the absence of CD40-CD40 ligand interactions; thus, the Em2(G11) antigen of the acellular LL represents a T-cell-independent antigen. Functionally, the encapsulating LL, and especially its major carbohydrate antigen, Em2(G11), seems to be one of the key factors in the parasite's survival strategy and acts by modulating the host immune response by virtue of its T-cell-independent nature.

Efficacy of toltrazuril and ponazuril against experimental Neospora caninum infection in mice.

Neosporosis is a disease affecting predominantly fetal development in cattle and dog hosts; and it may cause neuromuscular disfunction in infected newborn calves and pups. Predispositions--including, e.g. transient immunosuppression during pregnancy--may result in an increased dissemination of the parasite within the host or its offspring. Chemotherapeutic treatment of neosporosis may be an issue, provided that an appropriate drug is made available. In this respect, we describe the use of a mouse model for the evaluation of toltrazuril and ponazuril medication as a means of preventing parasite dissemination and subsequent formation of cerebral lesions. Toltrazuril- and ponazuril-treated mice were experimentally infected intraperitoneally (i.p.) with 2 x 10(6) Neospora caninum tachyzoites. The infection was monitored at three levels: clinically, by assessing symptoms, histologically, by assessing the occurrence of cerebral lesions and parasites by immunohistochemistry, and on the molecular level, by detection of parasite DNA using PCR. Chemotherapy using either toltrazuril or ponazuril, both applied in a drinking-water formulation (20 mg toltrazuril or ponazuril kg(-1) body weight day(-1)) completely prevented the formation of cerebral lesions in all treated animals, as assessed by immunohistochemistry. PCR analyses of these treated animals showed that DNA-detectability was reduced by 91% and 90% upon toltrazuril and ponazuril medication, respectively.