974 resultados para TOXOPLASMOSIS OCULAR


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Clinical and serological follow up examinations were performed on 203 persons, from three to twenty years of age, from the otolaryngology department of a hospital in the city of Rio de Janeiro, with no symptomatology suggesting toxoplasmosis, but suffering from chronic tonsillitis. According to results obtained during the first indirect immunofluorescence tests, the patients were divided into following groups: Group I (non-reactive IgG and IgM), 98 persons (48.3%); Group II (1:16 ≤ IgG ≤ 1:256 and non-reactive IgM), 74 persons (36.5%); Group III (IgM ≥ 1:1024 and non-reactive IgM), 18 persons (8.8%), and Group IV (IgG and IgM reactive), 13 persons (6.4%). One to two years later, 131 (64.5%) of the 203 persons were reexamined by a second indirect immunofluorescence test. In the case of 66 persons (Group I) whose serum was non-reactive in the IgG and IgM classes during the first indirect immunofluorescence test, serum conversion was observed in aproximately 21.2%. in 65 individuals (49.6%), (Groups II, III and IV),with reactive serum in the IgG classes during the first indirect immunofluorescence test, the second reaction showed an increase in titres in 20% of the cases, a decrease in 67.7% of the cases, or no alterations in 12.3 of the cases. In the IgM class, all 131 sera were non-reactive at 116 dilution the second immunofluorescence test, including the 13 cases that had previously been reactive in the immunoglobulin class, Symptomatology suggesting toxoplasmosis was only observed in one case during the second testing, this patient's principal physical sign being hypertrophied lymph nodes. during this period, the Toxoplasma antibodies showed titres of IgG 1:32000 and non-reactive IgM, whilst one year previously, during the first test, these titres were IgG 1:1024 and IgM 1:64. Differences in the age, sex and skin coloring of patients were not statistically significant as regards alterations in the indirect immunofluorescence test titres.

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Thirty-six persons living on a farm located in the state of Minas Gerais (Brazil) were studied. Nine of them had the glandular form of toxoplasmosis, between May and August, 1976. These nine cases of toxoplasmosis were confirmed serologically by immunefluorescence-IF-, presenting IgG antibody titres between 1:4096 and 1:32000 and IgM antibody titres between 1:16 and 1:8000. Twelve out of thirty-six persons studied were considered to be "dubious cases". They were defined either by presenting a clinical picture compatible with acquired toxoplasmosis, yet having low serologic titres, or inversely they did not have a clear clinical picture but had serologic evidence of recent Toxoplasma infection. Fifteen out of thirty-six persons studied showed neither serologic nor clinical evidence of recent Toxoplasma infection. The epidemiologic information suggests two possible modes of transmission: a) poorly cooked pork at a barbecue party; b) farm vegetables and soil contaminated with Toxoplasma gondii oocysts (rat-cat cycle). Serologic follow-up nine months later in the human farm population demonstrated still high IgG titres, yet they tended to decline and IgM titres became negative. Three years later most of the IgG titres continued to decline and were almost compatible with the titres obtained in Brazilian population surveys.

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Immunofluorescence tests (IF) for toxoplasmosis were performed on a total of 608 schoolchildren in elementary and junior high grades. 166 being in the Bonsucesso district (an urban region of Rio de Janeiro) and 442 children from locations within the lowlands of Jacarepaguá (with rural characteristics). All the IF-IgM were nonreactive, whilst 416 schoolchildren (68.4%) were IF-IgG serum-reactive ([greater than or equal to] 1:16). The percentages of serum-reactives in Jacarepaguá were significantly higher than in Bonsucesso, both as regards the total number of schoolchildren (p < 0.001), as also when subdivided according to the age-grades from six to eight years (p < 0.001) or from twelve to fourteen (p < 0.05). Both in Jacarepaguá and in Bonsucesso, the prevalence of reactions in the 12 to 14 year age-grade was significantly greater than in the 6 to 8 year age-grade (p < 0.001 in both cases). Expressively larger prevalences of serum reactions were found in Jacarepaguá among schoolchildren who preferred eating raw or undercooked meat, as well as among those having cats as pets; this occurred equally in the 6 to 8 year and in the 12 to 14 year age-grades. In Bonsucesso, the only significant difference was in the 6 to 8 year age-grades that had cats as pets. Thus, it has been verified that the risk of infection is greater and more precocious in localities with rural characteristics than in urban regions.

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A case-control study evaluating the association between mental retardation and toxoplasmosis was conducted among 845 school children in Belo Horizonte, MG, Brazil. Cases (450) were mentally retarded children attending a public school for special education. Controls (395) were children from the regular public school system. Clinical and anthropometric examinations and interviews were carried out to determine risk factors for toxoplasmosis and mental retardation. Diagnosis of Toxoplasma gondii infection was based upon an indirect immunofluorescent test (IFA); 55% of cases and 29% of controls were positive. The Relative Odds of mental retardation in children with positive serology was 3.0 (95% CI 2.2-4.0). Maternal exposure to cats and contact with soil were associated with an increased risk of mental retardation. Retinochoroiditis was fourfold more prevalent among cases than controls and was only diagnosed in T. gondii IFA positive participants. Congenital toxoplasmosis, in its subclinical form, appears to be an important component in the etiology of mental retardation, especially in high risk (lower socio-economic) groups. The population attributable risk was estimated as 6.0 - 9.0%, suggesting the amount of mental retardation associated with this infection.

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A slide micro-immunoenzymatic assay (micro-SIA) to detectantibodies to non-particulate Toxoplasma gondii antigens is described. This assay allows the diagnosis of toxoplasmosis infection in about 1 hr. Twenty-four determinations can be performed per slide. Five hundred ng of antigen and 5 or 10 µl drop of each reactive are necessary per well. The clear contrast of colours obtained for negative and positive sera after the test is finished, allows direct discrimination of the results. However, it is possible to quantify the results of the reaction using a minireader. Sera dilution cutoff value, determined as themost frequent titre for the general population, is 1:100. The toxoplasma micro-SIA correlates well with indirect immunofluorescence (IIF), its sensitivity is atleast three times as much as IIF. The test has an intra and inter assay variation coefficient of 5.46 per cent and of 6.24 per cent respectively. Sera obtained at random from argentinian people were analyzed and a 56 per cent of infection was found. The main features of the Toxoplasma micro-SIA are its simplicity, sensitivity, reproducibility, and the virtual absence of background making it very suitable for screening tests.

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Central serous chorioretinopathy (CSCR) is a vision-threatening eye disease with no validated treatment and unknown pathogeny. In CSCR, dilation and leakage of choroid vessels underneath the retina cause subretinal fluid accumulation and retinal detachment. Because glucocorticoids induce and aggravate CSCR and are known to bind to the mineralocorticoid receptor (MR), CSCR may be related to inappropriate MR activation. Our aim was to assess the effect of MR activation on rat choroidal vasculature and translate the results to CSCR patients. Intravitreous injection of the glucocorticoid corticosterone in rat eyes induced choroidal enlargement. Aldosterone, a specific MR activator, elicited the same effect, producing choroid vessel dilation -and leakage. We identified an underlying mechanism of this effect: aldosterone upregulated the endothelial vasodilatory K channel KCa2.3. Its blockade prevented aldosterone-induced thickening. To translate these findings, we treated 2 patients with chronic nonresolved CSCR with oral eplerenone, a specific MR antagonist, for 5 weeks, and observed impressive and rapid resolution of retinal detachment and choroidal vasodilation as well as improved visual acuity. The benefit was maintained 5 months after eplerenone withdrawal. Our results identify MR signaling as a pathway controlling choroidal vascular bed relaxation and provide a pathogenic link with human CSCR, which suggests that blockade of MR could be used therapeutically to reverse choroid vasculopathy.

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Trends in prevalence rates of onchocercal ocular lesions were examined over the period 1980 to 1990 using data from two cross-sectional surveys. There was evidence for increasing prevalence of anterior chamber microfilariae, iridocyclitis, optic atrophy, and chorioretinopathy. Large increases in prevalence, in particular, were seen for posterior segment lesions: optic atrophy increased from 2.7% to 6.4% and chorioretinopathy from 8.8% to 35.6%. Greatest increases in these lesions were seen in the Chachi which was attributed to the large increases in prevalence of microfilariae in the anterior chamber particularly in those aged 30 years or greater. The study findings suggest that ocular onchocerciasis is evolving in parallel with the well documented parasitological changes.

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Herpes simplex ocular infection is a major cause of corneal blindness. Local antiviral treatments exist but are associated with corneal toxicity, and resistance has become an issue. We evaluated the biodistribution and efficacy of a humanized anti-herpes simplex virus (anti-HSV) IgG FAb fragment (AC-8; 53 kDa) following repeated topical administration. AC-8 was found in the corneal epithelium, anterior stroma, subepithelial stromal cells, and retinal glial cells, with preferential entry through the ocular limbus. AC-8 was active against 13 different strains of HSV-1, with 50% and 90% mean effective concentrations (MEC(50) and MEC(90), respectively) ranging from 0.03 to 0.13 μg/ml, indicating broad-spectrum activity. The in vivo efficacy of AC-8 was evaluated in a mouse model of herpes-induced ocular disease. Treatment with low-dose AC-8 (1 mg/ml) slightly reduced the ocular disease scores. A greater reduction of the disease scores was observed in the 10-mg/ml AC-8-treated group, but not as much as with trifluridine (TFT). AC-8 treatment reduced viral titers but less than trifluridine. AC-8 did not display any toxicity to the cornea or other structures in the eye. In summary, topical instillation of an anti-HSV FAb can be used on both intact and ulcerated corneas. It is well tolerated and does not alter reepithelialization. Further studies to improve the antiviral effect are needed for AC-8 to be considered for therapeutic use.

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Different toxoplasma antigens were entrapped within liposomes and evaluated, in this form, for their ability to protect Swiss mice against toxoplasma infection: soluble tachyzoite antigen (L/TAg), tissue cyst (L/CAg), tachyzoite plus tissue cyst (L/TCAg) or purified antigen of tachyzoite (L/pTAg). The protein used in L/pTAg was purified from tachyzoites using a stage-specific monoclonal antibody which reacted at a molecular weight of 32 kD in SDS PAGE and silver stain using reduced condition. To compare the immuno-adjuvant action of liposomes and of Freund's Complete Adjuvant (FCA), another group of mice was immunized with soluble tachyzoite antigen (STAg) emulsified in FCA (FCA/TAg). Control groups were inoculated with (STAg) alone, phosphate-buffered saline (PBS), FCA with PBS (FCA/PBS) and empty liposomes (L/PBS). Mice were inoculated subcutaneously with these antigens six, four and two weeks before a challenge with 80 tissue cysts of the P strain of Toxoplasma gondii orally. All mice immunized with or without adjuvant showed a humoral response, as measured by Elisa. However, no correlation was found between antibody titer and protection against the challenge. All mice immunized with L/pTAg or L/TCAg survived (100), whereas 80% and 90% of mice from groups which received respectively PBS or FCA/PBS and L/PBS died. All mice immunized with antigens entrapped within liposomes (L/TAg, L/CAg, L/TCAg and L/pTAg) showed low numbers of intracerebral cysts.

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L'implant d’una lent intraocular fàquica tipus ICL (Implantable Collamer Lens) pot produir glaucoma agut per tancament angular degut a un bloqueig pupil•lar amb el consegüent augment de la pressió intraocular, el mecanisme i epidemiologia del qual no són ben coneguts. Aquest estudi preliminar pretén avaluar la incidència d'hipertensió ocular i glaucoma agut per tancament angular degut a bloqueig pupil·lar després de l'implant d'una lent posterior fàquica tipus ICL i plantejar hipòtesis sobre el seu mecanisme fisiopatològic.

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In a study of congenital transmission during acute infection of Toxoplasma gondii, 23 pregnant Balb/c mice were inoculated orally with two cysts each of the P strain. Eight mice were inoculated 6-11 days after becoming pregnant (Group 1). Eight mice inoculated on the 10th-15th day of pregnancy (Group 2) were treated with 100 mg/kg/day of minocycline 48 h after inoculation. Seven mice inoculated on the 10th-15th day of pregnancy were not treated and served as a control (Group 3). Congenital transmission was evaluated through direct examination of the brains of the pups or by bioassay and serologic tests. Congenital transmission was observed in 20 (60.6%) of the 33 pups of Group 1, in one (3.6%) of the 28 pups of Group 2, and in 13 (54.2%) of the 24 pups of Group 3. Forty-nine Balb/c mice were examined in the study of congenital transmission of T. gondii during chronic infection. The females showed reproductive problems during this phase of infection. It was observed accentuated hypertrophy of the endometrium and myometrium. Only two of the females gave birth. Our results demonstrate that Balb/c mice with acute toxoplasmosis can be used as a model for studies of congenital T. gondii infection. Our observations indicate the potential of this model for testing new chemotherapeutic agents against congenital toxoplasmosis.

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Hypereosinophilic syndrome (HES) is a myeloproliferative disorder characterised by persistent eosinophilia associated with multiple organ damage. The three criteria required for the diagnosis of the disease are: a sustained absolute eosinophilic count in the serum greater than 1500/μl present for longer than 6 months, no aetiology for secondary eosinophilia present and identification of signs and symptoms of end-organ involvement [1][2]. Despite significant progress in our understanding of the pathogenesis of some forms of hypereosinophilic syndrome, the current state of knowledge is still insufficient to formulate a new comprehensive etiologic definition of HES [3]. Very few reports can be retrieved describing ocular involvement in HES. Retinal arteriolar occlusions were observed in the pre-equatorial region and documented by angiography in one report [4], while the principal defects noted in a second report were occlusions of major retinal vessels, choroidal infarct, and patchy or delayed choroidal filling [5]. We present a case of extensive bilateral choroidal infiltrates in a patient suffering from idiopathic hypereosinophilia, potentially attributable to her disease.