Percutaneous Mitral Commissurotomy in Acute Pulmonary Edema

From January 1994 to July 1998, percutaneous mitral commissurotomy was performed in 520 patients. Of these patients, 7 (4 men and 3 women aged 31 ± 5.6 years) were dilated in an emergency situation of intractable pulmonary edema caused by severe mitral stenosis. Three patients required mechanical ventilatory support. Percutaneous mitral commissurotomy was performed with the Inoue balloon. The dilatation of the valve was undertaken even though the echocardiographic score of the valve was high. Percutaneous mitral commissurotomy resulted in an increase in the mitral valve area from 0.72 ± 0.18 cm² to 1.95 ± 0.18 cm² (P = 0.011) with a concomitant reduction in pulmonary artery systolic pressure from 82.5 ± 16.4 mmHg to 46.7 ± 11.6 mmHg (P = 0.018). One patient died (he had two cardiac arrests before the dilatation). During follow-up (mean 18 months), one patient presented with a restenosis, one an aggravation of mitral insuflciency grade, and four were in NYHA functional Class II. Thus, percutaneous mitral commissurotomy can be considered as a treatment of choice in patients with intractable pulmonary edema caused by severe mitral stenosis.     

Left Ventricular Perforation During Percutaneous Balloon Mitral Valvuloplasty With Emergency Surgery

Two cases of left ventricular (LV) perforation by balloon catheter following successful balloon mitral valvuloplasty are presented. The first patient was dilated first with a single straight-tip balloon catheter and after with a double balloon catheter. The second patient underwent a valvuloplasty with a double balloon catheter only. The subsequent tamponade was treated by immediate aspiration but without hemodynamic improvement. Both patients required emergency surgery with surgical repair of the LV apex, and both of them could be weaned. Both patients are well 18 months after the procedure. We discuss the mechanism of this serious complication and technical considerations to prevent it.     

A two-type model for the Cuban national programme on HIV/AIDS

We study deterministic and stochastic versions of a birth anddeath process for a two-type population with immigration forboth types. For the stochastic model we consider the case wherethe rates are time dependent, and also when they are constant,as is the case in our AIDS application. We derive the probabilitygenerating function of the bivariate process and the expectationsof the marginal processes. We also study the marginal behaviourof the bivariate process in a particular case where we supposethat the first event is an immigration, and examine the behaviourof the marginal processes divided by their expectations. Finally,we apply some of these results to a sexual-partner notificationsystem, as in the Cuban national programme on HIV/AIDS.     

An unusual case of multilocular cystic nephroma with prominent renal pelvis involvement

Multilocular cystic nephroma (MCN) is a relatively rare, benign tumor of uncertain etiology. It typically arises from the renal parenchyma and is often treated with nephrectomy. We report a case of MCN with unusual prominent renal pelvis extension. A left nephrectomy was performed. A multilocular cystic lesion was found in the removed specimen, which had a direct tumor extension into the renal pelvis. There were no signs of malignancy. The tumor extension into the renal pelvis has been found in very few reports. This growth pattern might be one of the characteristics of this benign renal tumor.     

CD44 IS AN INDEPENDENT PROGNOSTIC FACTOR IN CONVENTIONAL RENAL CELL CARCINOMAS

PURPOSE: CD44 is a transmembrane glycoprotein involved in cell-cell and cell-matrix interactions. De novo expression of CD44 and its variant isoforms has been associated with aggressive behavior in various tumors. Since few data are available concerning the role of CD44 in the biological behavior of locally confined renal tumors, we analyzed the expression of CD44 in a large set of conventional renal cell carcinomas to determine its prognostic value in association with other clinicopathologic variables. MATERIALS AND METHODS: Ninety-one patients with locally confined conventional renal cell carcinomas were studied. CD44 standard form (CD44H) and v6 isoform expressions were semiquantitatively evaluated on paraffin-embedded tumor tissue by immunohistochemistry. The prognostic value of the usual clinicopathological variables and CD44 expression was tested using Kaplan-Meier plots by the log rank test and Cox multiple hazard regression analysis. RESULTS: No immunostaining was observed in normal renal tissue. Thirty-two of the 66 conventional renal cell carcinomas (48%) showed CD44H membranous staining of the tumor cells. Only 2 cancers displayed CD44v6 immunostaining. Among the different clinicopathological variables analyzed, tumor stage (p = 0.001), nuclear grade (p = 0.01), size (p = 0.02), vascular (p = 0.05) and perirenal adipose tissue invasion (p = 0.005), and CD44H expression (p = 0.01) were found to be significant prognostic parameters for survival using univariate analysis. Moreover, multivariate analysis indicated stage, nuclear grade and CD44 expression as independent prognostic factors both for overall and disease-free survival. CONCLUSION: CD44 can be considered as a useful prognostic parameter in conventional renal cell carcinoma and may be used in evaluation of the outcome of these tumors.     

A Two-type Population Epidemic Problem

We reconsider a two-type population such that the birth rateof the second type depends on the size of the population ofthe first type. This problem was formulated by Kendall (1949)and Goodman (1953), then solved for constant parameters by Tapaswi& Roychoudhury (1984) and Gani & Tin (1984) (where thefirst type was female, and the second type, male). We generalizethe known results to cases where the parameters are time dependent.Analytic expressions for the first two moments are found. Forconstant parameters, we derive the asymptotic law for the process.