The rheological behavior of PBT/LLDPE and PBT/LLDPE‐g‐AA blends [where PBT is poly(butylene terephthalate), LLDPE is linear low‐density polyethylene, and AA is acrylic acid] under a capillary flow was investigated with a capillary rheometer. The Utracki equation was used to describe the viscosity–composition dependence of PBT/LLDPE and PBT/LLDPE‐g‐AA blends at low shear stresses. However, at high shear stresses, this equation was not suitable for these blending systems. There existed a maximum on the curves of the entrance pressure drop versus the blending compositions, and the interlayer slip factor β in the Utracki equation was related not only to the shear stress but also to the elasticity difference of the two blending components. Morphological observations indicated that at high shear rates, there existed two different morphologies at different positions of the extrudates, and this was the reason that the Utracki equation failed. Near the wall of the capillary, low‐viscosity PBT stratified, and this resulted in an additional decrease in the viscosities of the blending systems. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 206–213, 2003

To evaluate the efficacy of conservative management of intraocular retinoblastoma with chemoreduction combined with local therapy with or without plaque radiation in the preservation of the eye, and avoidance of external beam radiation therapy (EBRT) (success rate). From 1995 to 2000, 84 newly diagnosed patients with intraocular retinoblastoma were admitted to the Pediatric Department of the Hospital do Cancer A.C. Camargo, São Paulo, Brazil. All children were treated with 2 to 6 cycles of chemotherapy (carboplatin, vincristine, and etoposide) plus local therapy (cryotherapy, laser photocoagulation, and thermotherapy), or plaque radiation therapy during and/or after the chemotherapy. The Mann-Whitney test was used to compare means of quantitative variables. The chi test or the Fisher exact test were employed to verify the association between the outcome and the independent variables. For all tests alpha=5% was adopted. Success rate was higher for patients with bilateral tumors (54%) than for children with unilateral tumors (19%) (P=0.003). For patients with Reese-Ellsworth stages I, II, and III, no statistically significant differences in the success rates were noted in the group of unilateral (50%) and bilateral tumors (79.1%) (P=0.179). Among children with Reese-Ellsworth stages IV and V, the success rate was significantly higher for patients with bilateral tumors (40.7%) than for those with unilateral (0%) (P=0.012). Chemoreduction combined with local therapy, with or without plaque radiotherapy, is efficacious in avoiding enucleation and the use of external beam radiation therapy for children with intraocular retinoblastoma.

Evolução da terapêutica do retinoblastoma I N T R O D U Ç Ã OO sucesso na abordagem terapêutica dos pacientes com retinoblastoma requer um enfoque multidisciplinar (1) . Atenção especial dos pediatras na puericultura, quanto a alterações oculares (estrabismo, leucocoria -mancha branca na íris conhecida como "olho de gato") que podem alertar para o diagnóstico precoce. O reconhecimento destas alterações e o encaminhamento para o oftalmologista são fundamentais para o sucesso do tratamento desta doença.O retinoblastoma é o tumor maligno intra-ocular mais freqüente na criança, correspondendo a 2 a 4% dos tumores malignos pediátricos. Tem uma incidência de 11 casos novos por milhão em menores de 5 anos nos Estados Unidos (1:18.000 nascidos vivos = 200 casos/ano), sem diferença entre sexo ou raça, é o 4º tumor mais freqüente em crianças até 14 anos de idade (Brasil), 80% são diagnosticados antes dos 3-4 anos de idade e 30 a 40% são bilaterais (2) .

Early diagnosis is the gold standard for patients with Retinoblastoma and the pediatrician's ability to recognize the presenting signs and symptoms can lead to early diagnosis and efficient treatment.