The conversion of Toxoplasma gondii bradyzoites to tachyzoites may be responsible of toxoplasmic encephalitis (TE) in immunocompromised patients. To date there are no definitive systems available to ...detect bradyzoites in clinical samples. Among identified bradyzoite-specific antigens, the 65 kDa MAG1 is abundantly located in the cyst's matrix, and at lower levels in tachyzoites. However, the antigenic fragment encoded by the 1.2 kb exon of the MAG1 gene was recently demonstrated to be specific for the bradyzoite stage. Moreover, unlike other bradyzoite-specific genes, MAG1 transcription is regulated during the development of the bradyzoite stage. This was demonstrated by the detection of the MAG1 transcript in preparations containing parasites in the process of conversion from the tachyzoite stage to the bradyzoite stage, indicating a potential role of the MAG1 transcript as a bradyzoite marker. "In house" oligonucleotides deduced from the 1.2 kb portion of the MAG1 gene were employed in reverse transcriptase (RT)-PCR to investigate the mRNA expressed in cerebrospinal fluid (CSF) specimens obtained from AIDS patients with relapse of TE. Amplified fragments were then analyzed by Southern blot employing internal oligonucleotides as specific probes. The B1 gene was also investigated by RT-PCR and Southern blot for comparison.
Chlamydia is an intracellular bacterium implicated as potentially oncogenic for its tendency to cause chronic and persistent infections. These organisms have been frequently associated with several ...types of cancer including cervical dysplasia and cancer by C. trachomatis, lung cancer and cutaneous T-cell lymphoma by C. pneumoniae and a number of non-gastrointestinal MALT lymphomas such as ocular adnexal lymphoma by C. psittaci, suggesting a potential role. C. trachomatis, which causes ocular-genital infections in humans, was recently demonstrated at molecular and cultural level in patients with ocular cancer, thus implying also for this bacterium a role in the pathogenesis of the above malignancy. The pathophysiological processes and molecular mechanisms that lead to the development of chronic inflammatory disease, persistence, and ultimately cancer, still need to be clarified. This chapter describes the pathogenetic aspects of Chlamydial infections favouring the onset of chronic diseases and cancers as well as the diagnostic and clinical features in relation to Chlamydia species involved. The potential application of bacteria-eradicating therapy would certainly represent an exciting challenge for the next few years.
Toxoplasmic encephalitis (TE) is one the most frequent opportunistic infections in immunocompromised patients including those with AIDS. Disease in these persons is more commonly due to reactivation ...of chronic infection than to newly acquired infection. One important event underlying TE is the stage conversion between the encysted bradyzoites and the tachyzoites. The diagnostic investigation of stage conversion is not easy at serological level. In recent years, advanced improvement in T. gondii diagnosis has been achieved with the development of polymerase chain reactions (PCR)-based techniques, which detect the parasite's DNA in clinical specimens. Most of these assays make use of the multi-copy B1 gene of T. gondii, which is well conserved among different parasite strains. But this does not distinguish DNA of bradyzoites from DNA of tachyzoites, especially during latent infection or when specific treatment has been started. The ability to recognize individual stages by detecting specific genes would thus be crucial for correctly diagnosing TE. In the present study we carried out a novel "in house" multiplex nested (n)-PCR and reverse transcriptase (RT)-PCR method as a diagnostic tool for detecting and differentiating tachyzoite and bradyzoite-specific gene targets simultaneously in cerebrospinal fluid (CSF) specimens from patients with TE.
Accumulating evidence suggests that infectious agents may play a role in ocular adnexa lymphomas (OALs) of MALT-type 1-4. In particular, Chlamydia psittaci, the causative agent of psittacosis, has ...been detected by PCR in most patients from Italy or isolated eastern Asiatic countries with OALs in absence of other Chlamydia species 4-8. These patients have also been shown to have a complete or partial response to doxycycline, recognized to be a cheap and safe treatment in these patients 5,6. In contrast, OAL patients from other geographic areas and with different genetic background were found to be negative for C. psittaci DNA or had a quite variable response to antibiotic treatment, assuming that this pathogen might not play a ubiquitous role in OALs and that bacterial infection is not associated with OAL 8-12.
Este artículo presenta un protocolo desarrollado para la investigación de señales de desatención e hiperactividad en niños y adolescentes sobre aspectos conductuales, neuropsicológicos y clínicos. La ...primera fase es una entrevista telefónica. En la secuencia la evaluación es compuesta por una entrevista de despistaje presencial en la que es completado un inventario conductual (BPM) y son realizados testes neuropsicológicos (QI estimado por el Wisc-III y el Test-CPT-II). Caso existan indicadores de desatención e hiperactividad el participante pasa para la tercera fase. En la misma son concluidos los instrumentos neuropsicológicos y son aplicados a múltiplos informantes inventarios de evaluación conductual de la plataforma Aseba. Después de la realización de esa batería, es conducida una evaluación con un neurólogo infantil. En las devolutivas , los casos son encaminados para diversos acompañamientos en función de las señales relatadas. Enfoques multiprofesionales y de múltiplos informantes traen mayor clareza en la identificación de los señales compatibles con el TDAH y aumentan los criterios de especificidad cuanto a la indicación de acciones de intervención.
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