Relation between Cajal Cell Density and Radiological and Scintigraphic Outcomes in Patients with Ureteropelvic Junction Obstruction

<b><i>Introduction:</i></b> In this study, we aimed to investigate the correlation between Cajal cell density and preoperative and postoperative radiological and scintigraphic parameters in ureteropelvic junction obstruction (UPJO). <b><i>Methods:</i></b> The study group consisted of 41 renal units (38 consecutive patients; 13 female and 25 male) surgically treated for UPJO. UPJ specimens from patients were immuno-stained with CD117 (c-kit) antibody for interstitial Cajal cells (ICCs). The relation between Cajal cell density and preoperative and postoperative radiological and scintigraphic parameters was evaluated. <b><i>Results:</i></b> The mean age of the patients was 8.52 ± 8.86 (0–35) years. The density of Cajal cells was defined in 2 groups for convenient analysis as 0–5 cells (low) in 19 (46.3%) patients and &#x3e;5 cells (moderate-high) in 22 (53.6%). There was significant difference between the preoperative and postoperative anteroposterior diameters of the related kidneys in both Cajal groups (<i>p</i> = 0.001-low, <i>p</i> = 0.000-moderate-high) independent of Cajal cell density. Regression in hydronephrosis postoperatively was determined in both Cajal groups (77.8%-low, 64.7%-moderate-high); however, there was no difference between them (<i>p</i> = 0.39). Preoperative T1/2 was significantly longer in the low Cajal group (<i>p</i> = 0.02). Postoperative T1/2 decreased in both low (<i>p</i> = 0.000) and moderate-high (<i>p</i> = 0.001) Cajal groups, but no difference was found between them (<i>p</i> = 0.24). There was significant improvement in the kidney differential function after surgery in the low Cajal density group (<i>p</i> = 0.015) while there was no correlation between the scintigraphic success or improvement and Cajal cell density (<i>p</i> = 0.51). <b><i>Discussion/Conclusion:</i></b> ICC deficiency/density could not be shown as a predictive factor for the determination of success rate of pyeloplasty. Despite the lack of any evidence for the degree of deficiency as an indicator for the severity of obstruction and prediction of surgical success, further studies are needed for confirmation.

The role of body mass index at diagnosis of colorectal cancer on Black–White disparities in survival: a density regression mediation approach

Summary The study of racial/ethnic inequalities in health is important to reduce the uneven burden of disease. In the case of colorectal cancer (CRC), disparities in survival among non-Hispanic Whites and Blacks are well documented, and mechanisms leading to these disparities need to be studied formally. It has also been established that body mass index (BMI) is a risk factor for developing CRC, and recent literature shows BMI at diagnosis of CRC is associated with survival. Since BMI varies by racial/ethnic group, a question that arises is whether differences in BMI are partially responsible for observed racial/ethnic disparities in survival for CRC patients. This article presents new methodology to quantify the impact of the hypothetical intervention that matches the BMI distribution in the Black population to a potentially complex distributional form observed in the White population on racial/ethnic disparities in survival. Our density mediation approach can be utilized to estimate natural direct and indirect effects in the general causal mediation setting under stronger assumptions. We perform a simulation study that shows our proposed Bayesian density regression approach performs as well as or better than current methodology allowing for a shift in the mean of the distribution only, and that standard practice of categorizing BMI leads to large biases when BMI is a mediator variable. When applied to motivating data from the Cancer Care Outcomes Research and Surveillance (CanCORS) Consortium, our approach suggests the proposed intervention is potentially beneficial for elderly and low-income Black patients, yet harmful for young or high-income Black populations.