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Results for “TOXOPLASMA”

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PubMed1975

[Cytological study of a continuous swine embryonic kidney cell line with a persistent Toxoplasma infection].

Invasion of the PEK cell culture by toxoplasma did not cause any sharp disruption of the vital activity of the cells and failed to lead to their rapid degeneration. The observed changes in the morphology of the host cells were apparently chiefly the result of a purely mechanical pressure of the vacuoles on the nucleus and the cytoplasm, although the extreme forms of disturbances of the cell morphology were possibly associated with their greater injury. No complete "selfpurification" of the cells apparently occurred, since despite the marked reduction in the number of parasites a possibility of reinfection with toxoplasma of the culture at the later periods after the infection could not be excluded.

Animals↗
PubMed2002

Protective effect of DNA-mediated immunization with a combination of SAG1 and IL-2 gene adjuvant against infection of Toxoplasma gondii in mice.

OBJECTIVE: To characterize the immune response induced by SAG1 encoding plasmid combined with IL-2 gene adjuvant in mice and to assess the protective effect of this vaccination against toxoplasmosis. METHODS: Mice were co-injected intramuscularly with plasmid encoding Toxoplasma gondii SAG1 plus murine IL-2 expression vector at a dose of 100 microg. Booster immunizations were employed 2 more times at 3-week interval. As controls, mice were inoculated with PBS or empty plasmid pcDNA3. Humoral and cellular responses were assayed using ELISA for the determination of Ab, Ab isotype and IFN-gamma, as well as IL-4. To detect the integration and dissemination of DNA in the injected mice, PCR and in situ hybridization were performed. All mice were then infected with highly virulent RH tachyzoites of Toxoplasma gondii intraperitoneally. RESULTS: Significant increases in specific IgG levels were observed in mice after immunization three times with SAG1 expression plasmid. With respect to the IgG isotype, co-inoculation of IL-2 expression plasmid enhanced the level of IgG2a and the production of IFN-gamma. Challenging mice by vaccinating with combined plasmids with RH tachyzoites resulted in prolonged survival. CONCLUSION: Humoral and cytokine responses elicited by SAG1 DNA immunization can be modulated by co-inoculation with IL-2 expression plasmid. The use of DNA vaccine in combination with an appropriate cytokine gene to prevent T. gondii infection warrants further investigation.

Animals↗
PubMed2001

[Detection of DNA of Toxoplasma gondii in rat by using polymerase chain reaction].

OBJECTIVE: To study the significance of DNA of Toxoplasma gondii in peripheral blood. METHODS: DNA of T. gondii in peripheral blood of 50 infected rats was detected by polymerase chain reaction. A pair of primers was designed, according to the sequence P30 gene specific to T. gondii, to amplify DNA from T. gondii by PCR. RESULTS: The primers amplified DNA specifically from T. gondii and could not amplify DNA from humans, uninfected rat and mouse and from Trichomonas vaginalis and Entamoeba histolytica. DNA of two Toxoplasma parasites was detected by 35 cycles of amplification, indicating a fair sensitivity of the PCR system. CONCLUSION: PCR may have a value for early diagnosis of T. gondii infection in rat.

Animals↗
PubMed2001

[Exogenous nitric oxide induces apoptosis in tachyzoites of Toxoplasma gondii].

OBJECTIVE: To explore whether NO is able to induce apoptosis in Toxoplasma gondii tachyzoites. METHODS: Apoptosis induced by NO in T. gondii tachyzoites was investigated by TUNEL (terminal-deoxynucleotidyl transferase mediated d-UTP nick end labeling) method, electron microscopy and agarose gel electrophoresis. RESULTS: NO donor, sodium nitroprusside (SNP), was found to induce apoptosis in Toxoplasma gondii tachyzoites in a time- and dose-dependent manner by TUNEL detection. N-acetylcysteine, a NO scavenger, could inhibit SNP-induced apoptosis in the tachyzoites while potassium ferricyanide could not induce apoptosis in the tachyzoite. Electron macroscopy showed that SNP-treated tachyzoites possessed typical morphological features of apoptosis, including chromatin condensation below the nuclear membrane, nuclear pyknosis, and formation of apoptotic body. Agarose gel electrophoresis revealed that SNP-treated tachyzoite DNA fragment exhibited characteristic "DNA ladder" after 15 to 20 h. CONCLUSION: SNP, NO donor, might induce apoptosis in T. gondii tachyzoites in terms of characteristic morphological and biochemical features.

Acetylcysteine↗
PubMed2001

[The construction of recombinant plasmids of Toxoplasma gondii P30 and the immunoprotective activity of the P30 constructs].

OBJECTIVE: To identify the potential DNA vaccine candidate which can induce the protective immune response to Toxoplasma gondii by inoculating mice with plasmid DNAs encoding three different forms of P30 antigen (membranous secretory, and intracellular). METHODS: Three forms of recombinant plasmid: pcDNA3-P30Mb(contain the whole P30 gene sequence, including the gene encoding signal peptide and hydrophobic tail), pcDNA3-P30Se(contain the whole P30 gene sequence, without the gene encoding hydrophobic tail) and pcDNA3-P30In(contain the whole P30 gene sequence, without the gene encoding signal peptide) were constructed by PCR and subcloning technique. The mice were immunized with different forms of recombinant plasmids and IgG antibodies in the mice were detected by ELISA and Western blotting. RESULTS: Three forms of expression recombinant plasmid of Toxoplasma gondii P30 gene were successfully constructed. The P30 inserts were identified by restrictive enzyme digestion and sequencing. ELISA and Western blotting analysis demonstrated that specific IgG antibody could be induced in three immunized groups, but there was some difference in appearence time and intensity of IgG. CONCLUSION: Genetically immunization of mice with the recombinant plasmids could elicit specific IgG antibodies. In respect to IgG response, the immune efficiency of the three forms of recombinant plasmids was different at the beginning (2 wk), but 4 wk later approximately same.

Animals↗
PubMed2003

[Toxoplasma and toxoplasmosis].

Toxoplasmosis is a zoonotic protozoal disease, caused by an obligatory intracellular parasite of the genus Toxoplasma. The disease is widely distributed affecting more than a billion milliard people, worldwide. Raising sheep and cattle, handling and eating raw meat, interaction with domestic cats and climate conditions play an important role in the distribution of the disease. Both Toxoplasma and Plasmodium belong to the Phylum Apicomplexa, and are, therefore, almost similarly sensitive to anti-malarial drugs. Toxoplasmosis is considered to be viscerotropic in adults and children and neurotropic in fetal and newborn children. An accurate and fast diagnosis of the disease is highly important, particularly in pregnant women, since the results may affect both the mother and her fetus. The present study summarizes the old and new techniques available and their importance in the diagnosis of the disease.

Animals↗
PubMed2003

High Toxoplasma antibody prevalence among inhabitants in Jakarta, Indonesia.

We examined IgG antibody to Toxoplasma in sera from 1,693 inhabitants aged 20-85 years in Jakarta. The seroprevalence rate was 70%, without any significant differences between males (71%) and females (69%). Some epidemiological factors contributing to the high prevalences of antibody to Toxoplasma in inhabitants of urban areas in Indonesia were discussed.

Adult↗
PubMed1992

[Detection of Toxoplasma antibody among pregnant women and newborns in Jingmen].

748 sera from lying-in women and newborns were tested for anti-toxoplasma antibody with the method of IHA. The positive rate was 13.1% in lying-in women, and 4.01% in newborns. The occurrence of spontaneous abortions in anti-toxoplasma antibody positive women was 36.7%, which was higher than that in normal lying-in women. The occurrence of Fetal Distress and Asphyxia Neonatorum were 33.3% and 40% respectively, both of which were higher that those in normal newborns.

Animals↗
PubMed1992

Review: Toxoplasma gondii cellular invasion.

Toxoplasma gondii, the etiologic agent of toxoplasmosis, is a ubiquitous protozoan parasite that requires an intracellular site for growth and replication. The invasive process involves six steps: a) cellular recognition, b) parasite movements by means of a subpellicular microtubule cytoskeleton, c) cell to cell adhesion, d) rhoptry secretion of penetrating enhancing factor (PEF) with Ca++ and Ca++ activated ATPase dependence, e) conoid penetration, f) induction of a parasitophorous vacuole, a protective and exchange site, interiorization of the parasite. The invasion is an active, oriented and specific process depending on chemical factors as energy sources, cations, as well as microviscosity and membrane structures. Toxoplasma gondii stimulates T cell subsets and induces lymphokine (IFN gamma, IL2) release.

Animals↗
PubMedDate not supplied

Detection of toxoplasma IgM antibodies by ELISA method: a comparative study of different enzymes as markers.

Detection of toxoplasma IgM antibodies by employing enzyme linked immunosorbent assay (ELISA) technique was developed using different enzymes viz, horseradish peroxidase (HRP) (EC. 1.11.17), urease (EC. 3.5.15) and penicillinase (EC 3.5.2.6) as markers. Of these enzymes, HRP is light sensitive and needs dark chamber, also inactivated by preservative sodium azide. Similarly urease test system is extremely pH sensitive and demands special care during ELISA technique. Whereas penicillinase showed certain distinct advantages viz. stable at room temperature, high specific activity and economical. In the present studies it was observed that the sensitivity of penicillinase is similar to HRP and urease, marker enzymes used in commercially available diagnostic kit. The prominent feature of detection of toxoplasma IgM antibodies involving these three enzymes are: a) Shorter incubation time (About 2.5 hours) b) No false positive reaction. Moreover, these enzyme conjugates were prepared from F (ab')2 fragments of antitoxoplasma rabbit serum to elicit specific interaction with IgM antibodies only, avoiding cross interaction with other non-specific proteins like compliment systems and rheumatoid factor.

Animals↗
PubMed1992

Enzyme-linked immunosorbent assays for the detection of Toxoplasma gondii-specific antibodies and antigens in the aqueous humor of cats.

Serum and aqueous humor samples, collected from 14 clinically normal cats and 96 cats with clinical evidence of intraocular inflammation, were assayed with ELISA for Toxoplasma gondii-specific immunoglobulin M (IgM), T gondii-specific IgG, T gondii-specific antigens, total IgG, and total IgM. Additionally, serum was assayed with ELISA for feline leukemia virus p27 antigen and antibodies against the feline immunodeficiency virus as well as with an immunofluorescent antibody assay for antibodies against feline coronaviruses. Calculation of the Goldmann-Witmer coefficient (C-value) for the T gondii-specific antibodies detected in aqueous humor established the likelihood of local antibody production. Serologic evidence of present or prior infection by an infectious agent was found in 81.9% of the clinically affected cats from which serologic results were available (77/94 cats). Seropositive results for toxoplasmosis were found in 74.0% of the clinically affected cats. Anterior segment inflammation was found in 93.1% (81/87 cats from which information was available) of the clinically affected cats, most of which were older males. Toxoplasma gondii-specific antibodies were not detected in the aqueous humor of 6 seropositive, clinically normal cats. The C-values for aqueous T gondii antibodies were greater than 1 in 44.8% of the cats and greater than 8 in 24.0% of the cats. Response to treatment with clindamycin HCl was positive in 15/20 (75%) of the T gondii-seropositive, clinically affected cats treated with this drug. In 13/15 (86.7%) T gondii-seropositive, clinically affected cats having a C-value greater than 1, response to treatment with clindamycin HCl was positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2003

[Cloning, expression and purification of the major surface antigen P30 of Toxoplasma gondii].

OBJECTIVE: To obtain protein of the major surface antigen P30 of Toxoplasma gondii by molecular cloning. METHODS: The gene of P30 (containing the whole P30 gene sequence, without the gene encoding signal peptide) was obtained by polymerase chain reaction (PCR) using the primer designed according to the DNA sequence of P30. The recombinant plasmid was constructed using EcoR I, Xho I and was then transformed into E. coli Top10. The positive clones were identified by restriction enzymes and DNA sequence analysis. The fusion protein was induced by IPTG and purified by affinity chromatography using ProBond Resin (a kind of nickel-charged sepharose resin) and was identified by SDS-PAGE and Western blotting. RESULTS: The products of PCR, cleavage and link reaction were same as expected and the sequence of inserted fragment in the recombinant plasmid was same as reported except one synonymy mutation. A 58 kDa fusion protein was induced by IPTG and was purified by chromatography. CONCLUSION: Fusion protein containing Toxoplasma gondii P30 was achieved and was provided as experiment material for further research.

Animals↗
PubMed1978

[Cytochemical study of various stages of life cycle of Toxoplasma gondii. 10. Phosphatases in the parasites during developmental stages in cat's intestines].

Several methods of acid and alkaline phosphatese and ATPase detection using both natural and artificial substrates were applied to the intestinal stages of Toxoplasma gondii with negative results to reveal enzymatic activity in all the stages except the microgametocyte. Possible explanation of this unexpected phenomenon is discussed taking into account host-parasite relationships with intestinal stages of Toxoplasma and with coccidia in general.

Acid Phosphatase↗
PubMed2004

Serological evidence of Toxoplasma gondii infection among pregnant women in Auckland.

AIM: Severe congenital infection is a consequence of primary Toxoplasma gondii infection in early pregnancy. Antenatal screening is problematic because IgM antibody to Toxoplasma persists for months to years and thus may falsely indicate a recent infection. Serological screening for T. gondii infection is not currently included in routine antenatal testing in New Zealand. The aim of this study was to determine the prevalence of IgG and IgM antibody to T. gondii in pregnant Auckland women. METHODS: Five hundred serum samples submitted for routine antenatal blood tests were tested anonymously for IgG and IgM antibodies to T. gondii. One hundred consecutive serum samples were tested from five age groups: <20, 21-25, 26-30, 31-35, >36 years. The number of positive IgM results that would have occurred if there were routine screening for toxoplasmosis was estimated for the year 2000 by multiplying the number of women giving birth in the respective age groups by the proportion with positive IgM results in these samples. RESULTS: One hundred and sixty three (33%) women had IgG antibody to T. gondii and 12 (2.4%) also had IgM antibody. For the year 2000, if there had been routine screening for toxoplasmosis, 296 of 14 530 (2.03%, 95% CI: 1.8-2.2%) pregnant Auckland women would have had a positive IgM result. CONCLUSIONS: Screening would detect IgM antibodies in up to 2.2% of pregnant women. Significant and invasive further investigations would be required to identify the subset of pregnancies with fetal infection. Serological tests that are specific for recent primary infection are needed before routine screening could be considered for New Zealand. In the meantime, advice on how to avoid infection is necessary given that two thirds of pregnant Auckland women are susceptible to T. gondii.

Adult↗
PubMed1992

Studies on the epidemiology of child infections in the Bari area (south Italy). V. Epidemiology of Toxoplasma gondii infections.

Sera from 2790 0-15 aged infants and children were titrated for antibodies to Toxoplasma gondii by indirect immunofluorescent test. Maternal-derived antibodies were found at high rates in the first six months of life (32.9%). The positivity rate declined during the second semester of life (7.5%) and increased again with time (7.8% between 1 and 5 years, 11.2% between 5 and 10 years, 14.4% between 10 and 15 years). No statistically significant differences were found between the sexes. IgM specific antibodies were found at a titre of 1:32 or greater in 41 subjects (1.5%), who also exhibited IgG antibody titres ranging from 1:512 to 1:1024. Our results indicate a remarkable diffusion of toxoplasma infection in our area.

Adolescent↗
PubMed2003

[Effect of arthropod extracts on the multiplication of Toxoplasma gondii in mouse peritoneal macrophages].

Treatment of toxoplasmosis usually causes secondary effects. It is important to find active substances extracted from natural organisms. In this work we studied some arthropod extracts that have effect against Toxoplasma multiplication inside mouse macrophages. After studying 382 extracts, 23 were selected on the basis of the activity and we found that 13 extracts from orders Polydesmida, Lepidoptera, Orthoptera and Hymenoptera exerted an important inhibition of Toxoplasma multiplication.

Animals↗
PubMed2003

[Experimental study on the in vitro resistance to Toxoplasma gondii by murine lymphocyte].

AIM: To study the activities of in vitro resistance to the tachyzoite of Toxoplasma gondii by murine lymphocytes. METHODS: The rat's splenocyte culture method was used to observe the effects of lymphocytes themselves and lymphocytes together with Mandelic( MA) on the invasion and proliferation of T. gondii in lymphocytes. At the same time acetylspiramycin was used as positive control. RESULTS: As compared with other somatic cells, the lymphocytes invaded by T. gondii still inhibited and killed the toxoplasma organisms in the presence of immunity, the effect safety dose of MA on inhibition of the invasion of T. gondii was not notable while the inhibition of the proliferation of T. gondii in lymphocytes was remarkable. CONCLUSION: Cell-mediated immunity(CMI) was an important factor that host resists the T. gondii infection. So, we should pay attention to improving the organism's CMI and take proper medicine so as to enhance the effect of lymphocyte's resistance to T. gondii.

Animals↗
PubMed1992

Anti-toxoplasma serotitres in uveitis and ocular toxoplasmosis.

This study was based on anti-toxoplasma serotitres obtained from 80 normal healthy adults and 103 consecutive patients with anterior, posterior and panuveitis over a 42 month period. Twelve out of 80 (15%) normal healthy sera were found to have low titres (1:64 to 1:256), while 3 (3.8%) had high titres (1:1024 or higher). The distribution of serotitres in patients with clinical toxoplasmosis was significantly different from the population sample (p less than 0.001, chi-squared test). Similarly, the distribution of serotitres in patients with posterior uveitis (of which 28 out of 54 were clinically ocular toxoplasmosis) having serotitres of 1:1024 or greater, was found to be significantly different from the normal population (p less than 0.001, Chi-squared test), but not statistically different from those with clinical ocular toxoplasmosis. Hence, anti-toxoplasma serotitre is useful as a diagnostic screening tool only in patients with posterior uveitis. It is also useful in confirming cases of suspected clinically positive ocular toxoplasmosis in our local population.

Adolescent↗