Singlet oxygen luminescence as an in vivo photodynamic therapy dose metric: validation in normal mouse skin with topical amino-levulinic acid

Although singlet oxygen (1O2) has long been proposed as the primary reactive oxygen species in photodynamic therapy (PDT), it has only recently been possible to detect it in biological systems by its luminescence at 1270 nm. Having previously demonstrated this in vitro and in vivo, we showed that cell survival was strongly correlated to the 1O2 luminescence in cell suspensions over a wide range of treatment parameters. Here, we extend this to test the hypothesis that the photobiological response in vivo is also correlated with 1O2 generation, independent of individual treatment parameters. The normal skin of SKH1-HR hairless mice was sensitised with 20% amino-levulinic acid-induced protoporophyrin IX and exposed to 5, 11, 22 or 50 J cm−2 of pulsed 523 nm light at 50 mW cm−2, or to 50 J cm−2 at 15 or 150 mW cm−2. 1O2 luminescence was measured during treatment and the photodynamic response of the skin was scored daily for 2 weeks after treatment. As observed by other authors, a strong irradiance dependence of the PDT effect was observed. However, in all cases the responses increased with the 1O2 luminescence, independent of the irradiance, demonstrating for the first time in vivo an unequivocal mechanistic link between 1O2 generation and photobiological response

Age of Child, More than HPV Type, Is Associated with Clinical Course in Recurrent Respiratory Papillomatosis

Background: RRP is a devastating disease in which papillomas in the airway cause hoarseness and breathing difficulty. The disease is caused by human papillomavirus (HPV), 6 or 11 and is very variable. Patients undergo multiple surgeries to maintain a patent airway and in order to communicate vocally. Several small studies have been published in which most have noted that HPV 11 is associated with a more aggressive course. Methodology/Principal Findings: Papilloma biopsies were taken from patients undergoing surgical treatment of RRP and were subjected to HPV typing. 118 patients with juvenile-onset RRP with a least 1 year of clinical data and infected with a single HPV type were analyzed. HPV 11 was encountered in 40% of the patients. By our definition, most of the patients in the sample (81%) had run an aggressive course. The odds of a patient with HPV 11 running an aggressive course were 3.9 times higher that that of patients with HPV 6 (Fisher's exact p=0.017). However, clinical course was more closely associated with age of the patient (at diagnosis and at the time of the current surgery) than with HPV type. Patients with HPV 11 were diagnosed at a younger age (2.4y) than were those with HPV 6 (3.4y) (p=0.014). Both by multiple linear regression and by multiple logistics regression HPV type was only weakly associated with metrics of disease course when simultaneously accounting for age. Conclusions/Significance Abstract: The course of RRP is variable and a quarter of the variability can be accounted for by the age of the patient. HPV 11 is more closely associated with a younger age at diagnosis than it is associated with an aggressive clinical course. These data suggest that there are factors other than HPV type and age of the patient that determine disease course. © 2008 Buchinsky et al

Estudo fenotípico e genotípico da resistência aos macrolídeos de "Streptococcus pneumoniae" isolados em hospitais de Porto Alegre - RS

OBJETIVO: O objetivo deste estudo foi determinar a prevalência do S. pneumoniae resistente aos macrolídeos e identificar suas características fenotípicas e genotípicas. MÉTODOS: Amostras de S. pneumoniae isoladas entre maio de 2002 e agosto de 2004, em Porto Alegre (RS), a partir de materiais clínicos coletados de diferentes sítios anatômicos foram analisadas. Para o teste de difusão em ágar foram utilizados discos de eritromicina, claritromicina, azitromicina e clindamicina. As concentrações inibitórias mínimas de eritromicina foram determinadas nos isolados resistentes aos macrolídeos pelo método de diluição em ágar. Os fenótipos dos isolados resistentes aos macrolídeos foram investigados pelo teste de difusão em ágar e a genotipagem pela reação em cadeia da polimerase. RESULTADOS: Foram avaliados 229 isolados de pneumococos, e 12 mostraram-se resistentes aos macrolídeos (5,2%). Entre estes, 9 apresentaram o fenótipo MLSB (75%) e 3 o fenótipo M (25%). A reação em cadeia da polimerase indicou que 8 isolados com o fenótipo MLSB portavam apenas o gene ermB, enquanto que o gene mefE estava presente em todos os 3 isolados com o fenótipo M. Um isolado com o fenótipo MLSB apresentou ambos os genes. CONCLUSÃO: A resistência aos macrolídeos do S. pneumoniae em Porto Alegre permanece baixa, sendo devida principalmente à presença do gene ermB, com expressão do fenótipo MLSB.<br>OBJECTIVE: The aim of this study was to determine the prevalence of macrolide-resistant S. pneumoniae and to identify its phenotypic and genotypic characteristics. METHODS: Strains of S. pneumoniae isolated in the city of Porto Alegre between May 2002 and August 2004 from samples collected from different anatomical sites were analyzed. For the agar diffusion test, disks of erythromycin, clarithromycin, azithromycin and clindamycin were used. The minimum inhibitory concentrations of erythromycin were determined for macrolide-resistant isolates by the agar dilution method. Macrolide-resistant isolates were phenotyped by agar diffusion test and genotyped by polymerase chain reaction. RESULTS: A total of 229 pneumococcal strains were evaluated, 12 (5.2%) of which were macrolide-resistant. Among the 12 resistant strains, 9 (75%) presented the MLSB phenotype, and 3 (25%) presented the M phenotype. Polymerase chain reaction testing indicated that 8 MLSB phenotype isolates harbored the ermB gene only, whereas the mefE gene was present in all 3 M phenotype isolates. One MLSB phenotype isolate presented both genes. CONCLUSION: In Porto Alegre, the S. pneumoniae resistance to macrolides is still low since such resistance is due primarily to the presence of the ermB gene expressing the MLSB phenotype