Diss. (sammanfattning) Stockholm : Karol. inst., 2001. / Härtill 6 uppsatser.

Thesis (Ph. D.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 149 pages. Includes vita. Includes bibliographical references.

Trichodysplasia spinulosa (TS) é uma doença proliferativa de pele observada em pacientes imunocomprometidos. Caracteriza-se pela formação de espinhas de queratina conhecidos como espículas, acantose epidérmica, dilatação do folículo piloso, queratose actínica, queda dos pelos, pápulas foliculares e, que normalmente, se manifestam na região facial do paciente e extremidades do corpo (constantemente confundida com danos por exposição prolongada ao sol). A TS resulta da infecção ativa com o poliomavírus TSassociado (TSPyV), onde observa-se alta carga viral, expressão de proteína do vírus e formação de partículas. Este estudo desenvolveu métodos moleculares de detecção e sequenciamento do genoma total e parcial de TSPyV e utilizou-se destes métodos para determinar padrões de excreção e viremia em indivíduos imunocompromentidos e imunocompetentes, bem como explorar possíveis vias de transmissão. Ainda, características genéticas e filogenéticas do TSPyV também foram determinadas. Apesar de observamos alta taxa de excreção urinaria em indivíduos imunocomprometidos (57,7%), o vírus não foi encontrado em amostras de água do meio ambiente. Ainda em termos de excreção urinária do TSPyV, apenas 1,4% dos indivíduos imunocompetentes apresentaram virúria (diferente do que se observa para os poliomavirus JCPyV e BKPyV), mas o vírus foi encontrado em leite materno, sugerindo assim a possibilidade de haver transmissão vertical do TSPyV. As análises filogenéticas revelaram a existência de 2 linhagens de vírus circulantes em nosso meio, com características distintas dos já descritos na literatura. As diferenças observadas foram suficientes para que os vírus sejam caracterizados como novos genótipos circulantes de TSPyV. / Trichodysplasia spinulosa (TS) is a proliferative skin disease seen in immunocompromised patients. It is characterized by the formation of keratin spines known as spicules, epidermal acanthosis, hair follicle dilatation, actinic keratosis, hair loss, follicular papules and, which usually manifest in the facial region and extremities of the body (constantly confounded with damage from prolonged exposure to the sun). TS results from active infection with TS-associated polyomavirus (TSPyV), where high viral load, virus protein expression and particle formation are observed. This study developed molecular methods for detection and sequencing the total and partial genome of TSPyV and, employing these methods, determined patterns of excretion and viremia in immunocompromised and immunocompetent individuals, as well as explored possible transmission pathways. Genetic and phylogenetic characteristics were also determined. Although we observed high rate of urinary shedding in immunocompromised individuals (57.7%), the virus was not found in environmental water samples. Also in terms of urinary excretion of TSPyV, only 1.4% of immunocompetent individuals presented viruria (different from what is observed for polyomaviruses JCPyV and BKPyV), but the virus was found in breast milk, thus suggesting the possibility of vertical transmission. Phylogenetic analyzes revealed the existence of 2 circulating virus strains in our country, with different characteristics from those already described in the literature. The differences seem to be sufficient to characterize the viruses as new genotypes of TSPyV.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 6 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

The aim of this study was to develop a sensitive and specific method of detecting Toxoplasma gondii in the immunocompromised host which would reduce the need for other tests and would ensure the prompt initiation of the appropriate treatment, the effects of which could be monitored. Such a system would also be of benefit in theinvestigation of parasite/host interaction. Initial work investigated an antigen ELISA and the PCR using two different gene targets CB 1 and P30) to find the most sensitive system. The ELISA was insensitive but both PCR systems were capable of detecting parasite in blood, lymph and tissue samples from experimentally infected sheep. The B 1 PCR detected parasite earlier and over a significantly longer period than the P30 PCR, this greater sensitivity being due to the higher copy number of the B 1 gene. The PCR was applied to samples from patients with AIDS with the aim of finding an ideal sample for the diagnosis of infection. Parasite was detected in blood up to a month prior to clinical signs of infection, and therefore blood samples are ideal for monitoringpatients at risk of recrudescence of a chronic infection. This result indicates that recrudescence is not due to local reactivation, but is due to a more widespread parasitaemia. However, as parasitaemia was shown to be transient in cases of recrudescence, sampling time may be critical. Parasite was also detected in urine, biopsytissue and post mortem material, but was not detected in CSF.Dexamethasone was used to create a mouse model of recrudescence in the immunocompromised patient to further investigate interaction between the parasite and host. The PCR detected parasite in blood, brain and heart of chronically infected animals, however the detection rate was significantly higher in groups receiveing immunosuppressive therapy. Dexamethasone treatment mimicked the effects seen in the AIDS population where 30-35% of chronically infected individuals showed clinical signsof toxoplasmosis. However the PCR may also be detecting latent cysts in tissue samples, and blood samples were occasionally positive without clinical evidence of infection. This could be due to small amounts of parasite circulating intermittently, or to breakdownproducts from parasite degradation. There was therefore a need to differentiate between active and chronic infection, and this was carried out by developing a quantitative PCR based on competitive amplification. A novel Sma I restriction site was created within the P30 gene, and known amounts were co-amplified with samples. The amplified products were then digested with Sma I to differentiate between mutated and T. gondii DNA and the point at which product yield was equalled indicated the amount of original DNA present in the sample. The system was shown to work using human PM samples, and could be adapted to indicate a cut-off point where parasite DNA levels reveal active infection. In conclusion the B 1 PCR is the method of choice in detecting T. gondii in AIDS patients. Any patient in which active parasite is detected should be treated and closely monitored using the qPCR for any evidence of reactivation.

Trichodysplasia spinulosa (TS) é uma doença proliferativa de pele observada em pacientes imunocomprometidos. Caracteriza-se pela formação de espinhas de queratina conhecidos como espículas, acantose epidérmica, dilatação do folículo piloso, queratose actínica, queda dos pelos, pápulas foliculares e, que normalmente, se manifestam na região facial do paciente e extremidades do corpo (constantemente confundida com danos por exposição prolongada ao sol). A TS resulta da infecção ativa com o poliomavírus TSassociado (TSPyV), onde observa-se alta carga viral, expressão de proteína do vírus e formação de partículas. Este estudo desenvolveu métodos moleculares de detecção e sequenciamento do genoma total e parcial de TSPyV e utilizou-se destes métodos para determinar padrões de excreção e viremia em indivíduos imunocompromentidos e imunocompetentes, bem como explorar possíveis vias de transmissão. Ainda, características genéticas e filogenéticas do TSPyV também foram determinadas. Apesar de observamos alta taxa de excreção urinaria em indivíduos imunocomprometidos (57,7%), o vírus não foi encontrado em amostras de água do meio ambiente. Ainda em termos de excreção urinária do TSPyV, apenas 1,4% dos indivíduos imunocompetentes apresentaram virúria (diferente do que se observa para os poliomavirus JCPyV e BKPyV), mas o vírus foi encontrado em leite materno, sugerindo assim a possibilidade de haver transmissão vertical do TSPyV. As análises filogenéticas revelaram a existência de 2 linhagens de vírus circulantes em nosso meio, com características distintas dos já descritos na literatura. As diferenças observadas foram suficientes para que os vírus sejam caracterizados como novos genótipos circulantes de TSPyV. / Trichodysplasia spinulosa (TS) is a proliferative skin disease seen in immunocompromised patients. It is characterized by the formation of keratin spines known as spicules, epidermal acanthosis, hair follicle dilatation, actinic keratosis, hair loss, follicular papules and, which usually manifest in the facial region and extremities of the body (constantly confounded with damage from prolonged exposure to the sun). TS results from active infection with TS-associated polyomavirus (TSPyV), where high viral load, virus protein expression and particle formation are observed. This study developed molecular methods for detection and sequencing the total and partial genome of TSPyV and, employing these methods, determined patterns of excretion and viremia in immunocompromised and immunocompetent individuals, as well as explored possible transmission pathways. Genetic and phylogenetic characteristics were also determined. Although we observed high rate of urinary shedding in immunocompromised individuals (57.7%), the virus was not found in environmental water samples. Also in terms of urinary excretion of TSPyV, only 1.4% of immunocompetent individuals presented viruria (different from what is observed for polyomaviruses JCPyV and BKPyV), but the virus was found in breast milk, thus suggesting the possibility of vertical transmission. Phylogenetic analyzes revealed the existence of 2 circulating virus strains in our country, with different characteristics from those already described in the literature. The differences seem to be sufficient to characterize the viruses as new genotypes of TSPyV.

Opportunistic infection is always a potentially life threatening complication in pediatric oncology patients and hematopoietic stem cell transplant recipients. With the advances in various disease treatment protocols, the overall and event-free survivals of this high risk population improve significantly. In this thesis, the author reported a number of original studies to discuss different strategies in prevention of this serious complication. Firstly, the author demonstrates that pediatric oncology patients are still vulnerable to various vaccine-preventable infectious diseases up to 18 months after stopping chemotherapy. For those vaccine-preventable infectious diseases, pediatric oncology patients can mount a significant and persistent immune response to common inactivated vaccine (namely diphtheria-tetanus-pertussis vaccine). For non-vaccine preventable infectious diseases, regular monitoring of plasma viral load and strategic use of antiviral agents as pre-emptive or prophylactic agent is an effective approach to prevent infection. In hematopoietic stem cell transplant setting, adoptive transfer of acquired immunity from donor to recipient and incorporation of this parameter in donor selection process can be considered. The findings of the studies can be applied to clinical setting. The future direction of our studies includes the immune responses of other common vaccines namely pneumococcal vaccine and pandemic influenza vaccine in high risk population. The role of transfer of donor's varicella zoster immunity in prevention of herpes zoster infection in transplant recipient can be further explored. With the advances in supportive care of our vulnerable patients, the survival rate is expected to be further improved in the future. / by Frankie Wai Tsoi, Cheng. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (M.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 193-208). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.

Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 8 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.