Toxoplasmosis is an opportunistic disease caused by the protozoan parasite Toxoplasma gondii. The parasite is usually staved off by a healthy immune system and remains dormant in the body. In immunocompromised patients, the parasite can become active and spread throughout the body causing symptoms such as encephalitis, cognitive disorders, seizures, and death. Combination drug therapy is the usual treatment for toxoplasmosis; however, patients suffer from problems of intolerance, allergic reactions, and cytotoxicity. In an effort to identify new drug targets for toxoplasmosis, a series of compounds have been synthesized that can be used as tools to probe the unique pathways used by T. gondii to survive in the human host. One class of these compounds is pyridinyl imidazoles, which have been shown to be active against T. gondii MAP kinases. To set up a protein pull down assay, a biotinylated linker was synthesized. We have also synthesized a compound that’s being used to study the pathways involved in the most active and proliferative form of T. gondii.

A recent systematic literature and meta-analysis reported relative efficacy of trimethoprim-sulfamethoxazole (TMP-SMX) for the treatment of toxoplasmic encephalitis (TE) in HIV-infected adults. Here, we estimated relapse rates during secondary prophylaxis with TMP-SMX, and further explored differences in relapse rates prior to introduction of highly active antiretroviral therapy (HAART) and the widespread adoption of HAART. A systematic search of PubMed, Embase, and Cochrane Central Register of Controlled Trials yielded 707 studies whereby 663 were excluded after abstract screening, and 38 were excluded after full review leaving 6 studies for extraction. We performed double data extraction with a third-party adjudicator. Study designs varied with only one randomized study, four prospective cohorts and one retrospective cohort. Relapse rates were transformed using the Freeman-Tukey method and pooled using both fixed-effect and random-effects meta-analysis models. The TMP-SMX relapse rate was 16.4% (95% CI = 6.2% to 30.3%) based on random-effects models. When the disaggregated pre-HAART studies (n = 4) were included, the relapse rate was 14.9% (random effects; 95% CI = 3.7% to 31.9%). Analysis of two post-HAART studies indicated a relapse rate of 19.2% (random effects; 95% CI = 2.8% to 45.6%). Comparing the relapse rates between pre- and post-HAART studies were contrary to what might be expected based on known benefits of HAART therapy in this population. Nevertheless, cautious interpretation is necessary considering the heterogeneity of the included studies and a limited number of subjects receiving TMP-SMX reported in the post-HAART era.

A toxoplasmose é uma infecção mundial que é transmitida por carne contendo cistos teciduais, água ou legumes crus contaminados com oocistos, contato com felinos, ou transmissão vertical. A toxoplasmose é usualmente assintomática, mas pode causar doença severa no feto quando transmitida durante fase aguda na mãe. O rastreamento da toxoplasmose congênita é normalmente executado durante o pré-natal, pela detecção de anticorpos IgM específico ou pela demonstração de aumento dos títulos de anticorpos IgG para T.gondii. Neste trabalho, 160 mães IgM positivas em rastreamento externo foram avaliadas para IgM, IgG, IgA e avidez dos anticorpos IgG em ensaios usando Uréia e NH4SCN como agente caotrópico, e extrato salino e uma proteína recombinante ROP2 como antígeno. A maioria das mães com resultado positivo de IgM eram negativas (124) quando retestadas, 16 negativas para todos os testes e somente 36 casos de IgM e IgG positivos. Nossa reação foi convalidada pelo Kit VIDAS Toxo IgG (Biomerieux), as 15 amostras aleatórias foram concordantes na maioria das amostras, incluindo as 3 de baixa avidez. A maioria das mães com IgG e IgM positivas confirmadas apresentaram índices intermediário e alto de avidez, e apenas 3 com índice baixo de avidez, que é sugestivo de infecção aguda. O uso de proteína recombinante Rop2 como antígeno resultou em muitos falsos negativos. O rastreamento de toxoplasmose congênita em áreas de alta prevalência induz uma baixa eficiência da sorologia, altos índices de pacientes tratados e baixa detecção. Ensaios de avidez são promissores, mas a sua padronização é obrigatória. / Toxoplasmosis is a worldwide infection transmitted by meat containing tissue cysts, water or crude vegetables contaminated with oocysts, contact with feline or vertical transmission. Toxoplasmosis is usually asymptomatic, but it can cause severe disease to the fetus during acute mother infection. The screening of congenital toxoplasmosis is usually been performed during prenatal, by detecting specific IgM antibodies or by demonstration of a significant increase specific IgG antibodies. In this work, 160 confirmed IgM positive mothers by external screening were evaluated for IgM, IgG, IgA, and avidity by several approaches using Urea and NH4SCN as chaotropic agents, and saline extract and a recombinant protein Rop2 as antigen. Most mother (124) were IgM negative when retested, 16 negative for all T.gondii tests and only 36 IgM and IgG positive. Our avidity reaction was convalidated by Kit VIDAS Toxo IgG (Biomerieux), 15 aleatory samples were concordant in most samples, including the 03 low avidity. Most of confirmed IgG and IgM positive mothers presented intermediary or high avidity indexes, only 3 presenting low avidity index, sugestive of acute infection. Use of recombinant proteins Rop 2 as antigen resulted in high false negative. Screening congenital toxoplasmosis in high prevalent areas by IgM serology showed low efficiency, higher treatment rates and low detection of acute infection. Avidity assays are promising markers of recent infection, but false negatives could be frequent.

Publicación a texto completo no autorizada por el autor / La toxoplasmosis es una zoonosis producida por el parásito Toxoplasma gondii, teniendo al gato como hospedero definitivo y al hombre y otros animales como hospederos intermediario. Se evalúa un ensayo por inmunoabsorción ligado a enzimas (ELISA) y la técnica de aglutinación modificada (MAT) para el estudio de la infección por Toxoplasma gondii en perros de zonas urbanas de cercado de Lima y rurales de Cieneguilla durante el periodo 2017-2018. Se utilizaron un total de 120 sueros de perros, previo consentimiento de sus dueños, los cuales fueron evaluados como positivo y negativo ante la presencia de anticuerpos IgG anti T. gondii de acuerdo a cada tipo de técnica realizada. La concordancia de las dos pruebas fue evaluada mediante el índice Kappa (k) y para la determinación de sensibilidad y especificidad relativa se comparó con la prueba confirmatoria (Western blot). También se evaluó la frecuencia de infección (k), y los factores de riesgo mediante el test exacto de Fisher. La concordancia entre las pruebas de ELISA versus MAT se obtuvo un índice k=0.203; la concordancia entre las pruebas de ELISA versus Western blot fue de k=0.894 y entre MAT versus Western blot fue de k= 0.362. La sensibilidad relativa fue de 100% y 64% para ELISA y MAT respectivamente y la especificidad relativa fue de 92 y 73% para ELISA y MAT. La frecuencia de infección determinó que existe una diferencia significativa (p = 0.0032) en la seropositividad de T. gondii entre perros rurales y urbanos, obteniéndose que el 62.5% de los perros rurales y el 34.4% de los perros urbanos presentaron anticuerpos Ig G anti T. gondii. Con relación al factor de riesgo asociado al sexo se obtuvo para perros de zonas urbanas (p=0.5851) y en perros rurales (p=0.0686); en el factor asociado a la edad se obtuvo para perros de zonas urbanas (p=1 ) y rurales (p=0.013); en el factor asociado a la convivencia con gatos se obtuvo para perros de zonas urbanas (p=0.1933) y rurales (0.0061); con el factor asociado a la desparasitación se obtuvo para perros de zonas urbanas (p=0.0074) y rurales (p=0.0061). La técnica ELISA indirecto demostró ser la más apropiada para su uso en la detección de anticuerpos IgG anti T. gondii en perros urbanos como rurales, por lo cual puede ser empleada en estudios de ``screening´, debido a su fácil ejecución. En cuanto a los factores de riesgo como el sexo, edad, presencia de gatos y desparasitación en perros; se espera que la información evaluada sea de utilidad en futuros trabajos que permitan un ``screening´´ de la prevalencia de la infección de T. gondii mediante centinelas. / Tesis

This research was performed to determine; (1) the prevalence of Toxoplasma antibodies among starlings in Northern California, (2) if such starlings can transmit the disease, and (3) if tissues from seropositive starlings contain encysted forms of T. gondii.

Over the last decade, a significant amount of research has been done on sphingosine-1-phosphate (S1P). S1P regulates survival, proliferation and migration of breast cancer cells45, as well as playing an important but still unknown role in ovarian46, prostate, and glioma47 cell carcinomas. S1P plays a significant role in the regulation, proliferation and angiogenesis, and is therefore an area of considerable interest for cancer research. Previous research in our group has shown that two stilbenoid sphingosine analogs (1 & 2) were effective at sphingosine kinase (SphK) inhibition in addition to showing down-regulation of Vascular Endothelial Growth Factor (VEGF), a novel and distinctly different mechanism of action compared to reported sphingosine kinase inhibitors. Both compounds showed novel toxicity toward the parasite Toxoplasma gondii. T. gondii causes toxoplasmosis; a disease carried by up to 1/3rd of the world’s population and one that has been implicated in schizophrenia. Unfortunately, use of 1 & 2 as fluorescent probes is limited; their emission wavelengths fall between 360 and 380 nm, within the range of background fluorescence. The synthesis of five fluorescent sphingosine analogs is described herein, three of which have emission wavelengths above 420 nm. These compounds show single digit µM cytotoxicity towards T. gondii. The second generation synthesis of Fingolimod (FTY720) is also described. The process was optimized for large-scale production. Improvements to the synthesis included increased atom economy, purification and overall reaction efficiency. Yield was increased to 36%, from 33% in the first generation synthesis. Lastly, a synthesis of p-divinylbenzene is described, using “green” solvents and easy sample work-up. The product contains no meta impurities, an issue that arises when p-divinylbenzene is purchased commercially. / Thesis / Candidate in Philosophy

<p>Tris(hydroxymethyl)aminomethane (THAM) was a readily-available and economical amino-triol that was viewed as having a large untapped potential as a starting material. The full chemoselective functionalization and differentiation of the amino group and the three primary alcohol residues present in THAM was extensively investigated. The development of this methodology allowed for the rapid assembly of a differentiated core that lead to existing and new potential drug scaffolds.</p> <p>The discovery of a novel oxidative fragmentation and rearrangement process was made leading to the synthesis of differentiated oxazolidinone rings. This process allowed for the creation of novel chemical library situated around THAM-based oxazolidinones, as well as THAM-based 1,3-dioxanes.</p> <p>THAM was also used as a starting material for sphingosine analogs, including sphingosine 1-phosphate (S1P) and anticancer S1K inhibitors. Selective functionalization of the amine and one alcohol within an oxazolidinone ring allowed access to a new family of Linezolid-type oxazolidinones as well. Additionally, various triazole-based compounds were prepared, which allowed access to a new family of potential antifungal agents based on the lead compound Fluconazole.</p> <p>A total synthesis of the immunosuppressant molecule FTY720 was also reported, employing double Wittig-olefination protocol, from THAM. This synthesis avoided certain pitfalls that were present in previously documented literature methods. Along the pathway to FTY720, many intermediates and analogs were synthesized and tested for biological activity alongside the novel oxazolidinone compounds, resulting in interesting lead compounds for various biological applications. A UV-active FTY720 scaffold was also synthesized for potential future <em>in vivo</em> tracking of the immunosuppressant and its metabolites.</p> / Doctor of Philosophy (PhD)

Made available in DSpace on 2016-01-26T12:51:15Z (GMT). No. of bitstreams: 1 katiajairagalisteu_dissert.pdf: 6806647 bytes, checksum: ab1b8f140157ecb1f877fc0e8939bf8b (MD5) Previous issue date: 2007-06-22 / The aim of our study was to assess toxoplasmosis frequency and its risk factors in pregnant women and their newborns from São Paulo State Northwest region. From two thousand and a hundred pregnant women, 232 patients were screened in the referral outpatient clinics of two Health Units in São José do Rio Preto, between June 2005 and March 2006. Serological analysis was performed by the IgG indirect hemagglutination assay. The 133 positive pregnant women were also evaluated by the IgG-avidity test followed by ELISA assays for IgM and IgG for their newborns. The transmission risk factors were accomplished by interview. The independence among rates was determined by the Chi-Square method and odds ratio test with a 5% significance level. The obtained data showed 57.3% of IgG reagent pregnant women, all of them providing highly IgG-avidity results. The newborns showed positivity to IgG but they were all negative to IgM. Our data suggest that the transmission of this protozoan occurs in the studied area. However, we could not demonstrate congenital transmission. Ingestion of water from public reservoirs and unpasteurized milk were considered to be risk factors to toxoplasmosis in the Northwest region of São Paulo State. Due to the Toxoplasma gondii ascertained transmission, serological accompaniment of pregnant women it is highly recommended. / Os objetivos deste trabalho foram avaliar a freqüência de toxoplasmose e os fatores de risco associados em grávidas e seus neonatos do Noroeste Paulista. Das 2.100 gestantes atendidas em ambulatórios de referência nas duas Unidades de Saúde de São José do Rio Preto, no período de junho de 2005 a março de 2006, foram triadas 232 mulheres grávidas e realizado exame sorológico para a pesquisa de IgG por meio do teste de Hemaglutinação indireta. Destas, 133 grávidas forneceram resultado positivo, as quais foram também avaliadas pelo teste de avidez para IgG. Posteriormente, os neonatos foram investigados quanto a presença de IgM e IgG pelo teste de ELISA. O levantamento dos fatores de risco na transmissão da toxoplasmose foi realizado por entrevista. A independência entre as proporções foi determinada pelo método do teste Qui-Quadrado e o teste de razão de chances. O nível de significância adotado foi de 5%. Os resultados demonstraram que 57,3% eram IgG reagentes. Todas as grávidas positivas apresentaram alta avidez para IgG. Os recém-nascidos mostraram positividade para IgG, entretanto, foi observada negatividade para a pesquisa de IgM. A transmissão do protozoário ocorre na região, no entanto, a transmissão congênita não foi evidenciada. A água de consumo e o leite não-pasteurizado estão associados a essa infecção no Noroeste Paulista. O acompanhamento sorológico para o T. gondii, durante todo o pré-natal, é de extrema importância.

Made available in DSpace on 2014-12-17T14:13:56Z (GMT). No. of bitstreams: 1 CarlosAAG.pdf: 323369 bytes, checksum: 093c86d6d5662ee9fb5d64b4afd66037 (MD5) Previous issue date: 2004-02-19 / The objective of this study is to estimate the prevalence of Ocular Toxocariasis, Diffuse Unilateral Subacute Neuroretinitis (DUSN), Toxoplasma gondii infection and Ocular Toxoplasmosis in a student population in Natal-RN/Brazil and relate it to demographic, epidemiologic and socio-economic risk factors. The incidence of DUSN was observed in patients at the Federal University of Rio Grande do Norte Ophthalmology Service and the Prontoclinica de Olhos Ophthalmology clinic in Natal. In cases where a worm was found in the subretinal space, the result of treatment with photocoagulation using Green Laser (Eye Light ALCON) was evaluated in relation to final visual result. The sample was randomly selected among the schools of the four districts of Natal, according to the type of institution (public or private), its level (elementary or secondary), and study period (morning, afternoon or evening). The school population was studied from March to May, 2001. Initially, the students answered a questionnaire to evaluate demographic, epidemiologic and socio-economic risk factors. Afterwards, the following procedures were carried out: blood samples were taken for Toxoplasmosis (IgG, IgM) serology, hemogram, ophthalmological examination, consisting of clinical history, measurement of visual acuity, refraction under cycloplegia, biomicroscopy of the anterior segment and annexa, funduscopy and examination of extrinsic motility. The prevalence of Toxocariasis was 0.2% or 2 per one thousand students. The sample was insufficient to estimate the prevalence of DUSN. Seventy patients with DUSN diagnosis were examined from January, 2001 to January, 2003. A live worm was found in the subretinal space of all four patients in the acute phase, and these were treated with laser photocoagulation. After follow-up (average = 11.5 months), visual acuity improved in three eyes and remained unaltered in one eye. Worms were found in 22 of the 66 patients in the chronic phase, and these also were treated with laser photocoagulation. After a follow-up period of 13.1 months, on average, visual acuity improved in two of the patients, remained unchanged in 19 and worsened in one. The comparison of visual result before and after treatment was not statistically significant (p = 0.302). The diagnosis of DUSN in the acute phase, followed by prompt localization and destruction of the worm by photocoagulation, can improve the patient s vision. However, destruction of the worm by laser photocoagulation in eyes with DUSN in the chronic phase does not improve visual acuity. Seroprevalence for IgG was 46% (Confidence Interval CI 95%-42.9-49.2%) and for IgM it was 1.4% (CI 95% = 0.8-2.4%). The prevalence of ocular lesion was 1.15% (CI 95% = 0.6 - 2.0%). Socio-economic conditions were determinants in the prevalence of Systemic and Ocular Toxoplasmosis in the bivaried analysis and confirmed in the multivaried analysis (mother s scholarity illiterate/ OR = 2.9 and p < 0.001). The T. gondii infection prevalence, although high, was less than that found in studies performed in the South and Southeast of Brazil and that of Ocular Toxoplasmosis was completely discrepant, varying from 5 to 17 times less. Although important epidemiological variables such as owning a cat, drinking unfiltered water, and coming into contact with rivers or lakes showed an association in the preliminary analysis, they lost their influence when included in the logistic model. Future studies are scheduled to begin in March, 2004, in collaboration with other Brazilian and American universities in an attempt to discover the reason for these findings, as well as identifying the different strains of Toxoplasma gondii, and studying the sources of water utilized by the population of Natal Brazil / Esta pesquisa teve como objetivo, estimar a preval?ncia da Toxocar?ase Ocular, Neuroretininte Sub-aguda Difusa Unilateral (DUSN), Infec??o pelo Toxoplasma gondii e Toxoplasmose Ocular na popula??o de escolares de Natal-RN/Brasil e relacion?-la aos fatores de risco demogr?ficos, epidemiol?gicos e socioecon?micos. Estudar a incid?ncia de DUSN em pacientes atendidos no Servi?o de Oftalmologia da Universidade Federal do Rio Grande do Norte e Prontoclinica de Olhos, em Natal, bem como, avaliar, nos casos em que foi encontrada larva no espa?o sub-retiniano, o resultado do tratamento com fotocoagula??o utilizando o Laser Verde (Eye Light ALCON) em rela??o ao resultado visual. A amostra foi selecionada aleatoriamente e distribu?da nas escolas dos quatro distritos da cidade de Natal de acordo com a natureza da institui??o (p?blica ou privada), seu n?vel (fundamental ou m?dio) e turno em que o escolar estudava (matutino, vespertino ou noturno). A popula??o de escolares foi estudada no per?odo de mar?o a maio de 2001. Inicialmente, responderam a um question?rio para avalia??o de fatores de risco demogr?fico, epidemiol?gico e socioecon?mico. Depois foram feitos os seguintes procedimentos: coleta de sangue para realiza??o de sorologia para Toxoplasmose (IgG, IgM), hemograma, exame oftalmol?gico constando de hist?ria cl?nica, medida da acuidade visual, refra??o sob cicloplegia, biomicroscopia do segmento anterior e anexos, fundoscopia e exame da motilidade extr?nseca. A preval?ncia de Toxocar?ase foi de 0,2% ou 2 por mil escolares. A amostra n?o foi suficiente para estimar a preval?ncia de DUSN. Foram examinados 70 pacientes com diagn?stico de DUSN, no per?odo de janeiro de 2001 a janeiro de 2003. Foi encontrada larva viva no espa?o sub-retiniano de todos os quatro que se encontravam na fase aguda, e tratados com fotocoagula??o a laser. Ap?s acompanhamento dos pacientes (m?dia = 11,5 meses), a acuidade visual melhorou em tr?s olhos e permaneceu inalterada em um olho. Dos 66 pacientes na fase cr?nica, foi encontrada larva em 22 deles e tratados com fotocoagula??o a laser. Ap?s acompanhamento por um per?odo de 13,1 meses em m?dia, a acuidade visual melhorou em dois, permaneceu a inicial em 19 e diminuiu em um paciente. A compara??o do resultado visual antes e ap?s o tratamento, n?o foi estatisticamente significante (p = 0,302). O diagn?stico de DUSN na fase aguda, seguida por pronta localiza??o e destrui??o da larva por fotocoagula??o, pode melhorar a vis?o dos pacientes. No entanto, a destrui??o da larva por fotocoagula??o a laser em olhos com DUSN, na fase cr?nica, n?o melhora a acuidade visual. A soropreval?ncia para IgG foi de 46% (Intervalo de Confian?a -IC 95% - 42,9-49,2%) e para IgM foi 1,4% (IC 95% = 0,8-2,4%). A preval?ncia de les?o ocular foi 1,15% (IC 95% = 0,6 2,0%). As condi??es socioecon?micas foram determinantes na preval?ncia da Infec??o pelo T. gondii e Toxoplasmose Ocular na an?lise bivariada e confirmada na an?lise multivariada (escolaridade da m?e n?o alfabetizada/OR = 2,9 e p< 0,001). A preval?ncia de Toxoplasmose Sist?mica, embora elevada, foi menor do que a encontrada em estudos realizados no Sul e Sudeste do Brasil e, a da Toxoplasmose Ocular foi totalmente discrepante, variando de 5 a 17 vezes menos. Embora importantes vari?veis epidemiol?gicas, tais como possuir gato, beber ?gua n?o filtrada, ter contato com lagoas ou rios, tenham mostrado associa??o na an?lise preliminar, perderam sua influ?ncia quando inclu?das no modelo log?stico. Estudos futuros j? est?o planejados para ter inicio em mar?o pr?ximo, em colabora??o com outras Universidades do Brasil e dos Estados Unidos com a finalidade de encontrar a raz?o destes achados, bem como, identificar diferentes tipos de cepas do Toxoplasma gondii, e estudar as fontes de ?gua utilizadas pela popula??o de Natal-RN

The boy-to-girl ratio at birth (secondary sex ratio) is around 1.06 in most populations. The sex ratio may be influenced by many factors, such as stress and immunosuppression, age of parents, parity and sex of preceding siblings. The most common human protozoan parasite in developed countries, Toxoplasma gondii (prevalence 20% - 80%), is known to change the behaviour of its intermediate hosts, thereby increasing the probability of transmission to its definitive host (the cat) by predation. The results of our retrospective cohort study suggest that the presence of Toxoplasma gondii, can influence the secondary sex ratio in humans. Depending on the antibody concentration, the probability of the birth of a boy can increase up to a value of 0.72, which means that for every 260 boys born, 100 girls are born to women with the highest concentration of anti-Toxoplasma antibodies. In accordance with results on human subjects, laboratory mice with toxoplasmosis produced a higher sex ratio than controls, in the early phase of latent infection. Our further results showed that mice in the early phase of latent infection exhibited temporarily increased production of interleukin (IL)-12 and decreased production of IL-10. The mice showed decreased production of IL-2 and nitric oxide and decreased proliferation...