[Selective biopsy of the sentinel lymph node in patients with breast cancer and previous excisional biopsy: is there a change in the reliability of the technique according to time from surgery?]. / Biopsia selectiva del ganglio centinela en pacientes con cáncer de mama y biopsia escisional previa: ¿cambia la fiabilidad de la técnica según el tiempo transcurrido desde la cirugía?

AIM: To assess the influence of time on the reliability of sentinel lymph node biopsy (SLNB) in breast cancer patients with previous excisional biopsy (EB), analyzing both the sentinel lymph node detection and the lymph node recurrence rate. MATERIAL AND METHODS: Thirty-six patients with cT1/T2 N0 breast cancer and previous EB of the lesion underwent a lymphoscintigraphy after subdermal periareolar administration of radiocolloid, the day before SLNB. Patients were classified into two groups, one including 12 patients with up to 29 days elapsed between EB and SLNB (group A), and another with the remaining 24 in which time between both procedures was of 30 days or more (group B). Scintigraphic and surgical detection of the sentinel lymph node, histological status of the sentinel lymph node and of the axillary lymph node dissection, if performed, and lymphatic recurrences during follow-up, were analyzed. RESULTS: Sentinel lymph node visualization at the lymphoscintigraphy and surgical detection were 100% in both groups. Histologically, three patients showed macrometastasis in the sentinel lymph node, one from group A and two from group B. None of the patients, not even those with malignancy of the sentinel lymph node, relapsed after a medium follow-up of 49.5 months (24-75). CONCLUSION: Time elapsed between EB and SLNB does not influence the reliability of this latter technique as long as a superficial injection of the radiopharmaceutical is performed, proving a very high detection rate of the sentinel lymph node without evidence of lymphatic relapse during follow-up.

Finite-size effects in nanocomposite thin films and fibers.

Monte Carlo simulations of finite-size effects for continuum percolation in three-dimensional, rectangular sample spaces filled with spherical particles were performed. For samples with any dimension less than 10-20 times the particle diameter, finite-size effects were observed. For thin films in the finite-size regime, percolation across the thin direction of the film gave critical volume fraction (p(c)) values that differed from those along the plane of the film. Simulations perpendicular to the film for very thin samples resulted in p(c) values lower than the classical limit of ∼29% (for spheres in a three-dimensional matrix) which increased with film thickness. For percolation along thin films, while holding film thickness constant, p(c) increased with increasing sample size, which is a modification of the finite-sized scaling effect for cubic samples. For samples with a large aspect ratio (fibers) and a finite-sized cross-sectional area, the critical volume fraction increased with sample length, as the sample became quasi-one-dimensional. The results are discussed in the context of adding volume along or perpendicular to the percolation direction. From an experimental perspective, these findings indicate that sample shape, as well as relative size, influences percolation in the finite-size regime.

Hypereosinophilia, hyper-IgE syndrome, and atopic dermatitis in a toddler with food hypersensitivity.

We describe a 20-month-old girl with hypereosinophilia, hyper-immunoglobulin (Ig) E syndrome, and atopic dermatitis. Her peripheral eosinophil count and IgE plasma levels were 2.65 x 10(9)/L and 6702 IU/mL, respectively. Specific IgE levels for a variety of foods and inhalants were high and single-blind food challenges were positive for cow's milk, hen's egg, oat, wheat, and soy. When the patient received an extensively hydrolyzed milk formula, an exclusion diet, and 2 mg/kg of prednisone daily, the atopic dermatitis partially improved. Further improvement was observed with 1 mg/kg of azathioprine daily. Long-term clinical response was satisfactory. We suggest that food hypersensitivity should be ruled out in patients with hypereosinophilia, hyper-IgE syndrome, and atopic dermatitis. Azathioprine may be a good therapeutic alternative for treatment in such cases.

A comparative study of bronchodilator reversibility with albuterol, between asthma symptomatic and asymptomatic children according to ISAAC questionnaire in Mexico City.

BACKGROUND: Asthma is an important childhood disease. Recent surveys of the International Study of Asthma and Allergies in Childhood (ISAAC) suggest that the prevalence of asthma is increasing but these surveys do not include any pulmonary tests to confirm the possible diagnosis of asthma. OBJECTIVE: To compare bronchodilator reversibility with the albuterol test in symptomatic and asymptomatic 6-7-year-old children with asthma participating in the ISAAC survey and living in Mexico City. PATIENTS AND METHODS: We performed an observational, descriptive, comparative, cross sectional study in children participating in phase 3b of the ISAAC study. According to the ISAAC questionnaire children were classified as asthma symptomatic or asymptomatic. Both groups had bronchodilator reversibility with the albuterol test, using the guidelines of the American Thoracic Society to confirm or rule out the diagnosis of asthma. RESULTS: The asymptomatic group had a baseline FEV1 of 1.70 +/- 0.34 l/sec (mean +/- SD) and an endpoint FEV1 of 1.76 +/- 0.42 l/sec; in the symptomatic group the respective values were 1.51 +/- 0.41 l/sec and 1.57 +/- 0.44 l/sec (p < 0.05). A positive reversibility test was found in 13/136 (9.6 %) children in the asymptomatic group and in 22/112 (19.6 %) children in the symptomatic group (p < 0.05). CONCLUSION: Because of its low sensitivity, bronchodilator reversibility cannot be considered a diagnostic tool to confirm diagnosis of asthma.

Sudden Death of Citrus in Brazil: A Graft-Transmissible Bud Union Disease.

Citrus Sudden Death (CSD), a new, graft-transmissible disease of sweet orange and mandarin trees grafted on Rangpur lime rootstock, was first seen in 1999 in Brazil, where it is present in the southern Triângulo Mineiro and northwestern São Paulo State. The disease is a serious threat to the citrus industry, as 85% of 200 million sweet orange trees in the State of São Paulo are grafted on Rangpur lime. After showing general decline symptoms, affected trees suddenly collapse and die, in a manner similar to trees grafted on sour orange rootstock when affected by tristeza decline caused by infection with Citrus tristeza virus (CTV). In tristeza-affected trees, the sour orange bark near the bud union undergoes profound anatomical changes. Light and electron microscopic studies showed very similar changes in the Rangpur lime bark below the bud union of CSD-affected trees: size reduction of phloem cells, collapse and necrosis of sieve tubes, overproduction and degradation of phloem, accumulation of nonfunctioning phloem (NFP), and invasion of the cortex by old NFP. In both diseases, the sweet orange bark near the bud union was also affected by necrosis of sieve tubes, and the phloem parenchyma contained characteristic "chromatic" cells. In CSD-affected trees, these cells were seen not only in the sweet orange phloem, but also in the Rangpur lime phloem. Recent observations indicated that CSD affected not only citrus trees grafted on Rangpur lime but also those on Volkamer lemon, with anatomical symptoms similar to those seen in Rangpur lime bark. Trees on alternative rootstocks, such as Cleopatra mandarin and Swingle citrumelo, showed no symptoms of CSD. CSD-affected trees did recover when they were inarched with seedlings of these rootstocks, but not when inarched with Rangpur lime seedlings. These results indicate that CSD is a bud union disease. In addition, the bark of inarched Rangpur lime and Volkamer lemon seedlings showed, near the approach-graft union, the same anatomical alterations as the bud union bark from the Rangpur lime rootstock in CSD-affected trees. The dsRNA patterns from CSD-affected trees and unaffected trees were similar and indicative of CTV. CSD-affected trees did not react by immunoprinting-ELISA using monoclonal antibodies against 11 viruses. No evidence supported the involvement of viroids in CSD. The potential involvement of CTV and other viruses in CSD is discussed.

Incidence and epidemiology of Citrus tristeza virus in the Valencian community of Spain.

The first outbreak of citrus tristeza disease in Spain caused by Citrus tristeza virus (CTV) was recorded in 1957 in the Valencian Community (VC). In total c. 40 million trees, mainly of sweet orange and mandarin grafted on sour orange rootstocks, declined due to CTV. Large-scale surveys in different municipalities of the VC indicated that the disease spread very fast. Incidence increased from 11% in 1989 to 53% in 1998. Toxoptera aurantii and Aphis spiraecola (inefficient aphid vectors of CTV) predominated before 1985-87. Since then the relatively efficient vector Aphis gossypii has become dominant and induced an epidemic that has been modelled. The large number of A.gossypii that visited each clementine tree (estimated to exceed 97000 per year) explained the difference between the temporal pattern of spread of CTV in clementine which followed the Gompertz model and that in sweet orange (logistic model). The susceptibility of the different citrus species to CTV infection by aphids seems to depend on the number of young, succulent shoots produced. The epidemiological data allowed specific recommendations to be made to growers in order to facilitate a change to a modern citrus industry based on the use of selected varieties grafted on tristeza-tolerant rootstocks produced within a certification scheme. This has been done already in almost 90% of the VC citrus-growing area. The tristeza problem has been solved unless more aggressive isolates are introduced and become prevalent.