The miR-17～92 cluster collaborates with the Sonic Hedgehog pathway in medulloblastoma

Medulloblastomas (MBs) are the most common brain tumors in children. Some are thought to originate from cerebellar granule neuron progenitors (GNPs) that fail to undergo normal cell cycle exit and differentiation. Because microRNAs regulate numerous aspects of cellular physiology and development, we reasoned that alterations in miRNA expression might contribute to MB. We tested this hypothesis using 2 spontaneous mouse MB models with specific initiating mutations, Ink4c−/−; Ptch1+/− and Ink4c−/−; p53−/−. We found that 26 miRNAs showed increased expression and 24 miRNAs showed decreased expression in proliferating mouse GNPs and MBs relative to mature mouse cerebellum, regardless of genotype. Among the 26 overexpressed miRNAs, 9 were encoded by the miR-17∼92 cluster family, a group of microRNAs implicated as oncogenes in several tumor types. Analysis of human MBs demonstrated that 3 miR-17∼92 cluster miRNAs (miR-92, miR-19a, and miR-20) were also overexpressed in human MBs with a constitutively activated Sonic Hedgehog (SHH) signaling pathway, but not in other forms of the disease. To test whether the miR-17∼92 cluster could promote MB formation, we enforced expression of these miRNAs in GNPs isolated from cerebella of postnatal (P) day P6 Ink4c−/−; Ptch1+/− mice. These, but not similarly engineered cells from Ink4c−/−; p53−/− mice, formed MBs in orthotopic transplants with complete penetrance. Interestingly, orthotopic mouse tumors ectopically expressing miR-17∼92 lost expression of the wild-type Ptch1 allele. Our findings suggest a functional collaboration between the miR-17∼92 cluster and the SHH signaling pathway in the development of MBs in mouse and man.     

Electrophysiological investigation of auditory recruitment by averaged electroencephalographic-evoked response

An objective study of auditory recruitment by the method of the slow vertex-evoked potentials was carried out on 18 subjects presenting recruitment at 4 000 Hz. Evoked potentials were induced by tone burst stimulation of the recruiting ear and recorded by means of an active electrode located on the vertex. For each subject a study was made: (1) of the input-output curves of the N1P2 amplitudes and of the latencies of N1 and P2 of the evoked potentials as a function of the intensity of the stimulation and (2) of the best estimation of the input-output curve of N1P2 to a power function and a logarithmic function by the least-squares regression line, after checking that it was statistically possible. The results of the 18 recruiting subjects, classified according to their audiometric thresholds, were statistically compared with those of 9 normal subjects. The relation between the amplitude of the auditory-evoked response and the intensity of the stimulation could be expressed nearly equally well by a logarithmic function and a power function. The studies revealed a very significant increase of the slope of the least-squares regression line in recruiting subjects compared with normal subjects. No significant difference was obtained by the analysis of the latencies.     

The “Sentinel Chain”: a new concept for prediction of axillary node status in breast cancer patients

SummaryBackground and objectives More than half the breast cancer patients with positive sentinel lymph nodes (SLN) do not harbor additional metastases in non-sentinel nodes (NSN). The aim of this study was to identify a subgroup of patients with positive SLNs and negative NSNs, on the basis of tumor involvement patterns in multiple radioactive nodes.Methods Between 2000 and 2004, 290 patients with primary invasive breast cancer and clinically negative axillary nodes had a SLN biopsy in our breast unit. Radiotracer was identified intraoperatively in the axilla. All radioactive nodes were removed and radioactivity was measured in each node extracorporeally. Nodes were ranked according to radioactivity, constituting a “Sentinel Chain”, and the histopathological status of each node was reported. The different metastatic involvement patterns of the Sentinel Chain were correlated with the metastatic status of the NSNs after axillary dissection. Information was charted in a prospective database.Results Of 290 patients, 216 (74.5%) had multiple radioactive nodes. Ninety patients (31%) had SLN metastases. Fifty patients had multiple ranked radioactive nodes and positive SLNs. Twenty-five of these patients had a sequential involvement pattern, with tumor-bearing high radioactivity nodes, and uninvolved low-radioactivity nodes. In the 23 of these 25 patients who had axillary dissection, NSN involvement was detected in only one patient (4.3%), whereas in 24 patients with other involvement patterns of the Sentinel Chain, NSN involvement reached 54.2% (p<0.001).Conclusion Tumor-free status of NSN may be predicted using the Sentinel Chain concept in some breast cancer patients with positive SLNs.     

The Pediatric Rheumatology International Trials Organization criteria for the evaluation of response to therapy in juvenile systemic lupus erythematosus: prospective validation of the disease activity core set

OBJECTIVE: To validate and promulgate a core set of outcome measures for the evaluation of response to treatment in patients with juvenile systemic lupus erythematosus (SLE). METHODS: In 2001, a preliminary consensus-derived core set of measures for evaluating the response to therapy in juvenile SLE was established. In the present study, the core set was validated through an evidence-based, large-scale data collection process that led to the enrollment of 557 patients from 39 different countries. Consecutive patients with active disease were assessed at baseline and after 6 months. The validation procedures included assessment of feasibility, responsiveness, discriminant and construct ability, agreement in the evaluation of response to therapy between physicians and parents, redundancy, internal consistency, and ability to predict a therapeutic response. RESULTS: The following clinical measures were found to be feasible and to have good construct validity, discriminative ability, and internal consistency; furthermore, they were not redundant, proved responsive to clinically important changes in disease activity, and were associated strongly with treatment outcome and thus were included in the final core set: 1) physician's global assessment of disease activity, 2) global disease activity measure, 3) 24-hour proteinuria, 4) parent's global assessment of the patient's overall well-being, and 5) health-related quality of life assessment. CONCLUSION: The members of PRINTO propose a core set of criteria for the evaluation of response to therapy that is scientifically and clinically relevant and statistically validated. The core set will help standardize the conduct and reporting of clinical trials and assist practitioners in deciding whether a patient with juvenile SLE has responded adequately to therapy.     

Ambulatory blood pressure monitoring in children with isolated haematuria

Ambulatory blood pressure monitoring (ABPM) was performed in 29 children, ages 8.5-10.5 years (mean 11.6+/-3.0) with isolated haematuria (IH) and in 27 age, sex, weight and height matched healthy controls (C). Isolated haematuria was defined as >or=5 RBC/HPF on three separate urinalyses over a 3-month period with normal renal function, a normal appearing ultrasound examination of the kidneys and the absence of hypercalciuria. Haematuria had been documented for at least 3 years prior to ABPM. Daytime and nighttime periods were 0800-2200 and 2200-0800 hours, respectively. The total number of successful blood pressure readings was 21.8 and 20.7 per subject (90.0 and 86.1% of all attempted measurements) in IH and C, respectively. Mean 24-h, daytime and nighttime heart rate, mean arterial pressure, and systolic and diastolic blood pressure in IH did not differ from that of controls. Nocturnal dipping was present in all IH patients and was of equal magnitude to C (9.5 vs 8.4 and 13.7 vs 10.3% for average systolic blood pressure (SBP) and diastolic blood pressure (DBP) dips, respectively). We conclude that normal blood pressure values, as well as the circadian rhythm of blood pressure, are maintained in children with IH of at least 3 years' duration.     

Loss-of-function mutations of SURF-1 are specifically associated with Leigh syndrome with cytochrome c oxidase deficiency.

Mutations of SURF-1, a gene located on chromosome 9q34, have recently been identified in patients affected by Leigh syndrome (LS), associated with deficiency of cytochrome c oxidase (COX), the terminal component of the mitochondrial respiratory chain. To investigate to what extent SURF-1 is responsible for human disorders because of COX deficiency, we undertook sequence analysis of the SURF-1 gene in 46 unrelated patients. We analyzed 24 COX-defective patients classified as having typical Leigh syndrome (LS(COX)), 6 patients classified as Leigh-like (LL(COX)) cases, and 16 patients classified as non-LS(COX) cases. Frameshift, stop, and splice mutations of SURF-1 were detected in 18 of 24 (75%) of the LS(COX) cases. No mutations were found in the LL(COX) and non-LS(COX) group of patients. Rescue of the COX phenotype was observed in transfected cells from patients harboring SURF-1 mutations, but not in transfected cell lines from 2 patients in whom no mutations were detected by sequence analysis. Loss of function of SURF-1 protein is specifically associated with LS(COX), although a proportion of LS(COX) cases must be the result of abnormalities in genes other than SURF-1. SURF-1 is the first nuclear gene to be consistently mutated in a major category of respiratory chain defects. DNA analysis can now be used to accurately diagnose LS(COX), a common subtype of Leigh syndrome.     

Novel mutations in COX15 in a long surviving Leigh syndrome patient with cytochrome c oxidase deficiency

Background: Isolated cytochrome c oxidase (COX) deficiency is usually associated with mutations in several factors involved in the biogenesis of COX.

Methods: We describe a patient with atypical, long surviving Leigh syndrome carrying two novel mutations in the COX15 gene, which encodes an enzyme involved in the biosynthesis of heme A.

Results: Only two COX15 mutated patients, one with severe neonatal cardiomyopathy, the other with rapidly fatal Leigh syndrome, have been described to date. In contrast, our patient had a slowly progressive course with no heart involvement. COX deficiency was mild in muscle and a normal amount of fully assembled COX was present in cultured fibroblasts.

Conclusions: The clinical and biochemical phenotypes in COX15 defects are more heterogeneous than in other conditions associated with COX deficiency, such as mutations in SURF1.

     

Increased serum levels of TGFβ1 in children with localized scleroderma

Background  

There are neither sensitive nor specific laboratory tests for measuring disease activity in localized scleroderma (LS). Monitoring is done almost exclusively by clinical assessment. Our aim was to determine whether serum concentrations of TGFβ1 are a good biomarker of disease activity in children with LS.