Adenocarcinoma of the cervix and vagina in pediatric patients

Here we report our combined analysis of vaginal mesonephric adenocarcinoma (MA) in a 13 years old treated at our institution and of reported vaginal or cervical MA and clear-cell adenocarcinoma in 37 patients 18 years old or younger. Tumors in 27 patients arose in the vagina; 8 (21%) had metastases at diagnosis. The predominant symptom was vaginal bleeding; 62% of patients were exposed to diethylstilbestrol in utero. The 3-year survival estimate was 71% +/- 11%. Surgical treatment and metastasis at diagnosis were significant predictors of survival. The association between tumor excision and excellent outcome suggests that radical hysterectomy or pelvic exenteration is unnecessary. Radiotherapy as an adjunct may have contributed to this outcome.     

Tumor size as a predictor of outcome in pediatric non-metastatic osteosarcoma of the extremity

BACKGROUND: Better predictors of outcome would allow improved risk-adapted therapy for pediatric nonmetastatic osteosarcoma of the extremity. We investigated the predictive value of MR imaging-based measures of absolute and relative tumor size and volume at the time of diagnosis. We also assessed the relation of tumor size to age and histologic response. METHODS: We retrospectively abstracted demographic, treatment history, and outcome information of patients treated on a single institutional protocol. A single pediatric oncologic radiologist manually measured each primary lesion and the affected native bone in three dimensions on MR images obtained at the time of diagnosis. Eight parameters of tumor size were analyzed for their value in predicting overall survival (OS) and event-free survival (EFS). RESULTS: The median age of the 42 patients was 13.5 years (range: 5.9-18.7 years); 50% were female and 74% were Caucasian. Absolute tumor volume was an important predictor of OS (P < 0.05); absolute tumor depth (analyzed as a continuous variable) was a significant predictor of OS (P = 0.018) and EFS (P = 0.036). Relative measures of tumor size were not found to predict outcome. No relation was seen between tumor size and histologic response. CONCLUSIONS: Absolute tumor size at the time of diagnosis is significantly predictive of OS and EFS. If validated in a larger study, this indicator should be used in the design of risk-adapted treatment protocols for osteosarcoma.     

Patterns of abdominal relapse and role of sonography in Wilms tumor

This study characterizes the patterns of abdominal recurrence of Wilms tumor and describes the role of sonography in its detection. Twelve patients who had initial tumor recurrence in the abdomen were evaluated. Five patients had recurrence in the kidney; all had nephrogenic rests detected by computed tomography (CT) or magnetic resonance (MR) imaging but not by sonography. The remaining 7 patients had recurrence in the peritoneum (4), the nephrectomy site (2), or the regional lymph nodes (1); tumor spillage had occurred in five of these patients. Four recurrences were detected during therapy, and eight within 3 years after completion of therapy. Seven of the 12 recurrences were first detected by sonography. All 11 sonograms obtained at the time of relapse showed tumor recurrence. Nine patients died a median of 10 months after relapse. The results suggest that regular sonographic surveillance for 3 years after therapy is likely to reveal most abdominal recurrences. Supplementation with CT or MR imaging is indicated for detection of nephrogenic rests.     

A score for Bayesian genome screening

Bayesian Monte Carlo Markov chain (MCMC) techniques have shown promise in dissecting complex genetic traits. The methods introduced by Heath ([1997], Am. J. Hum. Genet. 61:748-760), and implemented in the program Loki, have been able to localize genes for complex traits in both real and simulated data sets. Loki estimates the posterior probability of quantitative trait loci (QTL) at locations on a chromosome in an iterative MCMC process. Unfortunately, interpretation of the results and assessment of their significance have been difficult. Here, we introduce a score, the log of the posterior placement probability ratio (LOP), for assessing oligogenic QTL detection and localization. The LOP is the log of the posterior probability of linkage to the real chromosome divided by the posterior probability of linkage to an unlinked pseudochromosome, with marker informativeness similar to the marker data on the real chromosome. Since the LOP cannot be calculated exactly, we estimate it in simultaneous MCMC on both real and pseudochromosomes. We investigate empirically the distributional properties of the LOP in the presence and absence of trait genes. The LOP is not subject to trait model misspecification in the way a lod score may be, and we show that the LOP can detect linkage for loci of small effect when the lod score cannot. We show how, in the absence of linkage, an empirical distribution of the LOP may be estimated by simulation and used to provide an assessment of linkage detection significance.     

Roles of protein kinase A and protein kinase G in synaptic plasticity in the visual cortex

Monocular deprivation leads to clear physiological and anatomical changes in the visual cortex known as ocular dominance plasticity. Protein kinase A (PKA) is necessary for ocular dominance plasticity, while protein kinase G (PKG) is not. We have now tested the role of PKA and PKG in long-term potentiation (LTP) and long-term depression (LTD). We have shown that PKA inhibitors have a major effect on both LTP and LTD in the visual cortical slices, whereas a PKG inhibitor affects LTP but not LTD. The PKA activator, 8-chloroadenosine-3',5'-monophosphorothioate, Sp-isomer (Sp-8-Cl-cAMPS), by itself induces a slowly rising form of LTP, which is occluded by theta-burst stimulation (TBS)-induced LTP. These results support the point that the PKA signaling pathway is crucial for neuronal plasticity in visual cortex, and the dissociation of the role of PKA and PKG in long-term synaptic plasticity in the visual cortex suggests that LTP alone is not sufficient to support ocular dominance plasticity, or LTD plays a more fundamental role than LTP in ocular dominance plasticity.     

Circulating concentrations of IGF-I and IGFBP-3 are not predictive of incidence or clinical behavior of pediatric osteosarcoma

BACKGROUND: Preclinical studies suggest a role of insulin-like growth factor-1 (IGF-1) in the proliferation of osteosarcoma cells in vivo. The purpose of this study is to address the relationship between serum levels of IGF-1 and its binding protein (IGFBP-3), and the clinical behavior and outcome of osteosarcoma in children, and to compare those levels present in osteosarcoma patients with a normal population. PROCEDURE: Serum IGF-1 and IGFBP-3 levels were determined by ELISA in 37 patients with osteosarcoma treated on the same treatment regimen (OS-91 protocol), and who had available serum samples from diagnosis. IGF-1 and IGFBP-3 levels were compared with those previously established in the normal population, matched for age and gender, and were correlated with the presence of metastatic disease, histologic response to preoperative chemotherapy, and event-free survival. RESULTS: In osteosarcoma patients the median IGF-1 level was 275 ng/ml (range, 105-613) and the median IGFBP-3 level was 3.4 mg/L (range, 2.3-5.1). IGF-1 levels differed from those in the normal population (P = 0.029); although we anticipated higher IGF-1 levels than normal children, 68% of observed standardized scores were less than 0. Furthermore, IGF-1 or IGFBP-3 levels failed to correlate with the presence of metastatic disease (P = 0.12 and P = 0.12, respectively), histologic response (Rosen-Huvos grades 3/4 vs. grades 1/2) (P = 0.95 and P = 0.71, respectively), or event-free survival (P = 0.52 and P = 0.41, respectively). There was a strong association observed between IGF-1 and IGFBP-3 levels (P < 0.001). CONCLUSIONS: In this retrospective study of 37 patients, we found that circulating levels of IGF-1 and IGFBP-3 are not predictive of the development or clinical characteristics of pediatric osteosarcoma. However, further studies on a larger patient population should be performed in order to investigate this relationship.     

Natriuretic Peptides in Chronic Kidney Disease

Background and objectives: B-type natriuretic peptide (BNP) and amino-terminal pro-B-type natriuretic peptide (NT-proBNP) are biomarkers of cardiovascular disease that is common in patients with chronic kidney disease (CKD). Conflicting data on the influence of glomerular filtration rate (GFR) on BNP and NT-proBNP levels in CKD may stem from failure to account fully for the effects of coexistent cardiac disease, dysfunction, and volume overload.Design, setting, participants, & measurements: Prospective head-to-head comparison of plasma BNP and NT-proBNP in ambulatory euvolemic CKD patients with normal LV ejection fraction and no manifest cardiac or vascular disease. GFR was estimated by the Modification of Diet in Renal Disease formula, BNP and NT-proBNP measured using Abbott AxSYM and Roche Elecsys assays, respectively, and cardiac morphology and function assessed by transthoracic echocardiography.Results: In 142 patients (42% female) of mean age 60 ± 11 yr, mean left ventricular ejection fraction was 71% ± 6%, GFR 38 ± 14 ml/min per 1.73 m², and median BNP and NT-proBNP level 59 and 311 pg/ml, respectively. Multivariate predictors of NT-proBNP level were GFR, β-blocker usage, LV mass index, and hemoglobin level. Plasma BNP was independently predicted by LV mass index and β-blocker usage but not GFR. In the 74 patients without diastolic dysfunction, there was a significant rise in NT-proBNP but not BNP as GFR declined.Conclusions: Unlike NT-proBNP, plasma BNP level is relatively independent of GFR. BNP may therefore be the more appropriate biomarker to screen for cardiac dysfunction in CKD.Patients with chronic kidney disease (CKD) are at increased risk of cardiovascular disease. Natriuretic peptides (NPs), biomarkers of myocardial dysfunction (1), offer the potential for early detection and risk stratification of cardiac disease, as evident in emergency department (2) and community (3,4) settings. This screening utility could be extended to CKD patients asymptomatic of cardiovascular disease.However, the precise influence of CKD on circulating levels of B-type natriuretic peptide (BNP) and amino-terminal pro-B-type natriuretic peptide (NT-proBNP), the two commonly used NPs in clinical practice, continues to be debated. Dependence of plasma BNP on glomerular filtration rate (GFR) has been reported among patients with and without heart failure (HF) (5,6), but this relationship may not be independent of cardiac or volume-related factors (7,8). The data on NT-proBNP in renal dysfunction are more concordant but were derived from populations that included patients with myocardial infarction, reduced left ventricular (LV) ejection fraction (LVEF), or HF (9,10). Indeed, most studies examining the impact of renal dysfunction on NPs uniformly included such patients (5,6,8–10). Recent Doppler myocardial imaging studies have shown that even HF patients with normal LVEF have reduced LV contractility compared with controls (11,12).To limit confounding by cardiac dysfunction or volume overload, we prospectively constituted a clinically euvolemic CKD cohort without symptoms or history of cardiac disease and normal LVEF and regional function. We measured circulating levels of both NPs, hypothesizing that, in these patients, BNP can be shown to be relatively independent of GFR compared with NT-proBNP if cardiac and loading factors can be comprehensively accounted for.