Transitional cell carcinoma of the endometrium associated with a benign ovarian Brenner tumor: a case report.

Transitional cell carcinomas (TCCs) of the endometrium are rare, and only 10 cases have been described to date. We report the case of a 46-year-old woman who developed both a TCC of the endometrium and a benign ovarian Brenner tumor. Such an association has not yet been reported in the literature. Immunohistochemical studies of the uterine tumor showed cytokeratin 7 positivity and cytokeratin 20 negative staining, which was consistent with a Müllerian derivation. Human papilloma virus (HPV) immunostaining as well as polymerase chain reaction (PCR) analysis using primers for HPV types 6, 11, 16, and 18 failed to detect viral DNA. The coexistence of a TCC of the endometrium and an ovarian Brenner tumor might be coincidental but raises the possibility of a field effect, as seen with multifocal endometrioid tumors or multiple urinary tract TCCs.

Reflections of my cultural nursing experience in Mexico.

One home care nurse's experience in Mexico has meaning for her daily practice in Georgia. Other home care nurses will also profit from this nurse's insight into culturally diverse populations and the importance of delivering this care to all patients and families.

A computer simulation of radio-frequency ablation of the endocardium.

A computer simulation of radio-frequency (RF) ablation of the endocardium is performed. The objective is to quantify some of the parameters affecting lesion growth, and to obtain theoretical data which can be used as a guide to maximize the lesions obtained with the procedure. The model under consideration consists of a block of heart tissue with the catheter electrode making contact at a right angle on one side (endocardium) and a large grounded electrode on the other side. An RF electrical current flows between the electrodes, heating the tissue. The simulations provide information on the time evolution of the tissue temperature, lesion dimension and tissue resistance. A first set of calculations is based on an applied RF voltage that maintains the maximum tissue temperature at 100 degrees C. The results reveal that: 1) the lesions achievable by RF ablation are considerably larger than those obtained with a hot-tip catheter of the same size; 2) increasing the electrode radius enlarges the lesion because of an associated increase in contact surface area; 3) an increase in electrode length also enlarges the lesion because of the larger convective losses to the blood flow; 4) a large difference in temperature may exist between the electrode and the tissue because of the cooling effect of the blood flow; and 5) the lesions grow as long as power is applied. Other simulations in which the RF voltage is constant show that the lesions can be enlarged by lowering the applied voltage while increasing the duration. Agreement and discrepancies between the simulations and reported experimental results are identified.(ABSTRACT TRUNCATED AT 250 WORDS)

Numerical model for radio-frequency ablation of the endocardium and its experimental validation.

A theoretical model for the study of the radio-frequency (RF) ablation technique is presented. The model relies on a finite-element time-domain calculation of the temperature distribution in a block of tissue, resulting from the flow of RF (< 1MHz) electrical current. A thermal damage function is used to calculate the extent of the lesion on the basis of the temperature elevation and the duration of exposure. This work extends the model proposed by Haines [1] by including a more realistic and variable geometry, the cooling effect of the blook flow and a transient analysis. Furthermore, the nonlinearity caused by the temperature dependence of the tissue properties is also considered. The complexity of the model being appreciable, an experiment demonstrating its validity is also described. While remaining workable, the experiment is sophisticated enough to lead to convincing conclusions. It consists in measuring the temperature distribution and the time-dependent electrode resistance during "ablation" of a tissue-equivalent material. Various electrode configurations and electrical excitations are investigated. In all cases, the experimental results agree reasonably well with the numerical calculations. This confirms that the model is accurate for the investigation of RF ablation.