Evaluation of Smad2/3 and Smad4 as inhibitors of estrogens and Ski protein as a predictive factor in T1, T2 N0 breast carcinomas

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Background: Smad proteins are TGF-β intracellular substrates, and Ski protein is a negative regulator of TGF-pathway. Tamoxifen's inhibition in breast cancer cells is mediated through TGF-β and Smad proteins. The purpose of our study was to investigate the activation of Smad2/3, Smad4, and Ski proteins in breast carcinomas and correlate their expression with each other and with hormonal receptors, as well as with other clinicopathological parameters such as the tumor size and grade, and the Distant Disease Free and the Overall Survival. Methods: One hundred forty-seven paraffin-embedded specimens from 22 in situ and 125 invasive ductal node-negative carcinomas were used, for which we had a mean follow-up time of 96 months. ER and PR status, as well as the expression of Smad2/3, Smad4, and Ski proteins were evaluated using immunohistochemistry. Staining of 5% of the tumor cells was adopted as a threshold. SPSS13 for windows was used for the statistical analysis of the results. Results: Smad2/3 and Smad4 were strongly correlated with each other (p < 0,001) and inversely correlated with patients’ DDFS (Kaplan-Meier plots, p = 0,004 for Smad2/3 and p = 0,026 for Smad4) and OS (Kaplan-Meier plots, p = 0,034 for Smad2/3 and p = 0,017 for Smad4). Smad2/3 was proved to be an independent prognostic factor in grade 1 tumors, while Smad4 was inversely correlated with PR expression (p = 0,028) and had a strong prognostic value in ER+ tumors (p = 0,02). Ski protein had a strong association with tumor grade (p < 0.001) and was found to be an independent prognostic factor in Cox regression analysis (p = 0,006, exp(B) = 4,98). Conclusions: Smad 2/3 and Smad 4 not only are tumor suppressor molecules, but also inhibit ER dependent gene expression. This inhibition is lost when Smad's expression is reduced, and that is a potent explanation for Smad 4 prognostic value in ER positive tumors. Moreover the correlation with PR expression, may be due to the fact that PR is an indicator of ER pathway's integrity and also to PR's enallaktiki activation by ER-β. From the other hand, Ski protein acts as an oncogene in breast carcinogenesis and contributes to the development of a more aggressive tumor phenotype.

No significant financial relationships to disclose.

Heparin-induced thrombocytopenia type II: a serious hazard in preemptive renal transplantation: a case report

Heparin-induced thrombocytopenia (HIT) type II (HIT II), is an immune-mediated complication of heparin therapy, associated with arterial and venous thrombosis. Herein we have reported a case of a 23-year-old woman who developed HIT following a living related donor, preemptive, renal transplantation. The patient was preoperatively exposed to both unfractionated and low-molecular-weight heparin as she underwent five hemodialysis sessions. HIT caused right common and external iliac vein and renal graft artery thrombosis, resulting in graft loss. Heparin-free hemodialysis was continued, and the patient was successfully treated with anticoagulation by the direct thrombin inhibitor lepirudin for both the thromboses and for hemodialysis. Finally, she was accepted for the continuous ambulatory peritoneal dialysis program. This report highlighted the importance of clinical awareness as far as previous heparin exposure is concerned for establishing an early diagnosis and delivering treatment of this life-threatening prothrombotic complication of heparin administration.

HPRT deficiency as the cause of ESRD in a 24-year-old patient: a very rare presentation of the disorder

A 24-year-old male with end-stage renal disease (ESRD) and disproportionately high uric acid plasma concentration was admitted to our unit. After studying the patient's medical history, as well as that of the entire family, hyperuricemia was discovered in his brother, while microscopic examination of his brother's and mother's urine revealed abundant uric acid crystals. After performing purine metabolic studies, it was determined that the two siblings suffered from partial hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency (Kelley-Seegmiller syndrome). This report highlights the importance of clinical awareness and a thorough examination of the patient's medical history for establishing an early diagnosis and commencing treatment for such rare inherited metabolic disorders to prevent renal failure.

Individualization of theophylline infusion rate on the basis of a nonlinear compartmental pharmacokinetic model

In the present paper, a nonlinear compartmental model for theophylline pharmacokinetics is developed. The analytical solution of the model, in parametric form, is derived under plateau conditions for plasma metabolite concentration. The parameters are obtained from plasma and urine data using best fitting techniques and their values are used in order to calculate maintenance intravenous infusion. Numerical simulation is then performed in order to compare the drug concentration obtained by our approach with that of alternative intravenous regimens. The differences argue for individualized dosage regimens, since theophylline is a drug with a narrow therapeutic window and its concentration at the active sites strongly depends on characteristic parameters of the patient's response. Our results show that it is possible to estimate the patients' parameters during the first 8 h after intravenous administration of the drug and these parameters can be used to design an individualized dosage regimen in patients receiving theophylline intravenously.