Early versus late GD-DTPA MRI enhancement in experimental glioblastomas

Purpose:

To compare early versus late enhancement in two glioblastoma models characterized by different infiltrative/edematous patterns.

Materials and Methods:

Three weeks after inoculation into nude mice of U87MG and U251 cells, T1‐weighted images were acquired early (10.5 min), intermediate (21 min) and late (30.5 min) after a bolus injection of Gd‐DTPA at 300 μ mol/kg dosage. EARLY_TH and LATE_TH were the corresponding volumes with an enhancement higher than a threshold TH, defined by the mean (μ) and standard deviation (σ) on a contralateral healthy area. ADD_TH was the enhancing volume found in LATE_TH but not in EARLY_TH. T2 imaging of both tumors was performed, and T2 mapping of U251.

Results:

In all tumors, LATE_TH was significantly higher than EARLY_TH for TH ranging from μ+σ to μ+5σ. The ADD_TH/EARLY_TH ratio was not significantly different when U251 and U87MG tumors were compared. In the U87MG tumors, some enhancement was observed outside the regularly demarcated T2‐hyperintense area. In the U251 tumors, irregularly T2 demarcated, a large portion of ADD_μ+3σ had normal T2 values. At histology, U251 showed a higher infiltrative pattern than U87MG.

Conclusion:

In these models, the increase over time in the enhancing volume did not depend on the different infiltrative/edematous patterns and was not closely related with edema. J. Magn. Reson. Imaging 2011;33:550–556. © 2011 Wiley‐Liss, Inc.     

Using a combination of MLPA kits to detect chromosomal imbalances in patients with multiple congenital anomalies and mental retardation is a valuable choice for developing countries

Conventional karyotyping detects anomalies in 3-15% of patients with multiple congenital anomalies and mental retardation (MCA/MR). Whole-genome array screening (WGAS) has been consistently suggested as the first choice diagnostic test for this group of patients, but it is very costly for large-scale use in developing countries. We evaluated the use of a combination of Multiplex Ligation-dependent Probe Amplification (MLPA) kits to increase the detection rate of chromosomal abnormalities in MCA/MR patients. We screened 261 MCA/MR patients with two subtelomeric and one microdeletion kits. This would theoretically detect up to 70% of all submicroscopic abnormalities. Additionally we scored the de Vries score for 209 patients in an effort to find a suitable cut-off for MLPA screening. Our results reveal that chromosomal abnormalities were present in 87 (33.3%) patients, but only 57 (21.8%) were considered causative. Karyotyping detected 15 abnormalities (6.9%), while MLPA identified 54 (20.7%). Our combined MLPA screening raised the total detection number of pathogenic imbalances more than three times when compared to conventional karyotyping. We also show that using the de Vries score as a cut-off for this screening would only be suitable under financial restrictions. A decision analytic model was constructed with three possible strategies: karyotype, karyotype + MLPA and karyotype + WGAS. Karyotype + MLPA strategy detected anomalies in 19.8% of cases which account for 76.45% of the expected yield for karyotype + WGAS. Incremental Cost Effectiveness Ratio (ICER) of MLPA is three times lower than that of WGAS, which means that, for the same costs, we have three additional diagnoses with MLPA but only one with WGAS. We list all causative alterations found, including rare findings, such as reciprocal duplications of regions deleted in Sotos and Williams-Beuren syndromes. We also describe imbalances that were considered polymorphisms or rare variants, such as the new SNP that confounded the analysis of the 22q13.3 deletion syndrome.     

The diagnostic value of VEGF expression in the renal parenchyma tumors

Tumor angiogenesis emerged as an important concept in cancer therapy over two decades ago, and was extensively studied by the discovery of VEGF family members. VEGF, also known as vascular permeability factor, is a generic name for VEGF-A, which is one of the members involved in angiogenesis. VEGF is the most important angiogenic factor, with significant effects on tumor angiogenesis. Tumor expression of VEGF was not the first angiogenesis indicator, but a growing number of studies have demonstrated that VEGF could be a prognostic factor, independent even from microvascular density, which is increased by its expression. Renal parenchyma tumors are a heterogeneous group of malignancies, difficult to classify or monitor, which prompts for the assessment of novel markers useful for the investigation of tumor histogenesis or prognostic assessment. VEGF expression in renal parenchyma tumors is poorly studied, with most of the articles published so far focusing on antiangiogenic usage in renal carcinoma therapy. The aim of this study is to detect the expression pattern of VEGF in renal parenchyma tumors by immunohistochemistry.     

Atypical variant of lichen planus mimicking normal skin histology

We present the case of a 69-year-old Caucasian and non-smoker patient with erythematous, itchy, violaceous lesions on the ankles, wrists, lower legs, forearms and trunk developed within 15 months. Her condition was diagnosed as prurigo and she was treated for a long period of time with antihistaminic drugs, with no resolution of lesions. In October 2008, she presented to a Private Practice of Dermatology in Timisoara. The dermatologist noticed the development of violaceous lesions on her trunk. The patient had similar lesions on the ankles, wrists, lower legs, and forearms for the last eight months. At physical examination many hyperpigmented, 1 to 6 cm, thin plaques were present on the flanks, shoulders, and infra-mammary area. There was no vaginal involvement. This eruption had a good response to topical glucocorticoids, but recurred multiple times after discontinuation of treatment. A biopsy specimen showed some histopathological features of lichen planus.