Automorphism Faithfulness Metrics for Symmetric Graph Drawings.

In this paper, we present new quality metrics for symmetric graph drawing based on group theory. Roughly speaking, the new metrics are faithfulness metrics, i.e., they measure how faithfully a drawing of a graph displays the ground truth (i.e., geometric automorphisms) of the graph as symmetries. More specifically, we introduce two types of automorphism faithfulness metrics for displaying: (1) a single geometric automorphism as a symmetry (axial or rotational), and (2) a group of geometric automorphisms (cyclic or dihedral). We present algorithms to compute the automorphism faithfulness metrics in O(n logn) time. Moreover, we also present efficient algorithms to detect exact symmetries in a graph drawing. We then validate our automorphism faithfulness metrics using deformation experiments. Finally, we use the metrics to evaluate existing graph drawing algorithms to compare how faithfully they display geometric automorphisms of a graph as symmetries.

On-site CAD templates reduce surgery time for complex craniostenosis repair in infants: a new method.

INTRODUCTION: The surgical correction of craniostenosis in children is a time-consuming and taxing procedure. To facilitate this procedure, especially in infants with complex craniostenosis, we refined the computer-aided design and manufacturing technique (CAD/CAM) based on computed tomography (CT)-generated DICOM data. We used cutting guides and molding templates, which allowed the surgeon to reshape and fixate the supraorbital bar extracorporeally on a side table and to control the intracorporal fit without removing the template. METHOD AND PATIENTS: To compare our traditional concept with the possibility of preoperative virtual planning (PVP) technique, the surgical treatment and courses of 16 infants with complex craniostenosis following fronto-orbital advancement (FOA) (age range 8-15 months) were analyzed in two groups (group 1: traditional, control group n = 8, group 2: CAD/CAM planned, n = 8). RESULTS: While in both groups, the head accurately reshaped postoperatively during the follow-up; the CAD group 2 showed a significantly shorter operating time with a mean of 4 h 25 min compared with group 1 with a mean of 5 h 37 min (p = 0.038). Additionally, the CAD group 2 had a significantly lower volume of blood loss (380 ml vs. 575 ml mean, p = 0.047), lower blood transfusion volume (285 ml vs. 400 ml mean, p = 0.108), lower fresh frozen plasma (FFP) volume (140 ml vs. 275 ml mean, p = 0.019), shorter stay in the pediatric intensive care unit (PICU) (3 vs. 5 days mean (p = 0.002), and shorter total length of hospital stay (6 days vs. 8 days mean, p = 0.002). CONCLUSION: CAD/CAM cutting guides and templates offer optimizing operative efficiency, precision, and accuracy in craniostenosis surgery in infants. As shown in this single-center observational study, the use of on-site templates significantly accelerates the reconstruction of the bandeau. The virtual 3D planning technique increases surgical precision without discernible detrimental effects.

The Impact of Immersion on Cluster Identification Tasks.

Recent developments in technology encourage the use of head-mounted displays (HMDs) as a medium to explore visualizations in virtual realities (VRs). VR environments (VREs) enable new, more immersive visualization design spaces compared to traditional computer screens. Previous studies in different domains, such as medicine, psychology, and geology, report a positive effect of immersion, e.g., on learning performance or phobia treatment effectiveness. Our work presented in this paper assesses the applicability of those findings to a common task from the information visualization (InfoVis) domain. We conducted a quantitative user study to investigate the impact of immersion on cluster identification tasks in scatterplot visualizations. The main experiment was carried out with 18 participants in a within-subjects setting using four different visualizations, (1) a 2D scatterplot matrix on a screen, (2) a 3D scatterplot on a screen, (3) a 3D scatterplot miniature in a VRE and (4) a fully immersive 3D scatterplot in a VRE. The four visualization design spaces vary in their level of immersion, as shown in a supplementary study. The results of our main study indicate that task performance differs between the investigated visualization design spaces in terms of accuracy, efficiency, memorability, sense of orientation, and user preference. In particular, the 2D visualization on the screen performed worse compared to the 3D visualizations with regard to the measured variables. The study shows that an increased level of immersion can be a substantial benefit in the context of 3D data and cluster detection.

Osteoclastic craniectomy for scaphocephaly in infants results in physiological head shapes.

INTRODUCTION: Sagittal synostosis leading to scaphocephaly is the most common type of craniostenosis being operated. Different treatment options are known, but the optimal treatment method is still controversial. Head growth indicated by measurements of the head´s circumference and cephalic index (CI) are valid surrogate parameters for normal head shapes in children. The aim of the study was to analyze if osteoclastic craniectomy (OC) in scaphocephaly children at four to ten months of age results in normal head shapes. PATIENTS AND METHODS: Twenty-seven patients with scaphocephaly underwent OC between 2003 and 2011. The mean patient age at the time of surgery was 6.75 months. The body weight was between 6.1 and 9.3 kg, mean 8.0 kg. The average duration of surgery was 108 minutes. The mean blood loss during the procedure was 168 ml and the mean amount of erythrocyte transfusion was 152 ml. The mean time spent on the ICU was 1.48 days and the mean of total hospital stay was 5.81 days. The operative method is described. During the mean follow-up time of 6.3 years (min 3.8, max 10.4, median 7.1) focus was set on the patient´s head growth and cephalic index (CI) following OC. For statistical reason the follow up period was divided into three groups: follow up 2-4 years, 5-7 years and 8-10 years. RESULTS: For all cases the total head growth was 9.5cm (mean) during the follow up period of 6.3 years. Analyzing the mean head growth by bootstrapping analysis, the three observational groups showed a significant increase of the head circumference in all cases being analyzed: group 1 p=0.003, group 2 p=0.005 and group 3 p=0.028 Evaluation of the CI showed a statistically significant change from a pathologic value of 0.67 (mean) preoperatively to a normal value of 0.78 (mean) postoperatively during the follow up analyzing all patients. To precise these findings, the bootstrapping analysis showed in the first period an increase of the mean CI not reaching statistical significance (p=0.351). Analyzing the second and third period the CI significantly increased in both groups (p=0.016 and p=0.037). All patients showed a nearly complete re-ossification during the follow up period. No secondary operation was necessary in any patient of this cohort. CONCLUSION: As shown in this single-center observational study, the surgical intervention significantly improved the cephalic index and resulted in a symmetric head shape with excellent aesthetic appearance. The results were not dependent on postoperative helmet therapy, and compliance of caregivers. Re-ossification reached 100% within the observation period. According to these data, we recommend osteoclastic craniectomy as the method of choice in infants six to twelve months of age.

[Reduction of treatment time for children in the trauma room care : Impact of implementation of an interdisciplinary trauma room concept (iTRAPS)]. / Verkürzung der Versorgungszeit im Trauma-Schockraum für Kinder : Auswirkungen der Einführung eines interdisziplinären Schockraumkonzepts (iTRAPS).

INTRODUCTION: In addition to infrastructural and conceptual planning, smooth interdisciplinary cooperation is crucial for trauma room care of severely injured children based on time-saving management and a clear set of priorities. The time to computed tomography (CT) is a well-accepted marker for the efficacy of trauma management. Up to now there are no guidelines in the literature for an adapted approach in pediatric trauma room care. METHODS: A step-by-step algorithm for pediatric trauma room care (Interdisciplinary Trauma Room Algorithm in Pediatric Surgery, iTRAPS) was developed within the framework of an interdisciplinary team: pediatric surgeons, pediatric anaethesiologists, pediatric intensivists and pediatric radiologists. In two groups of patients from January 2014 to April 2015 (group 1) and from July 2015 to January 2017 (group 2) process quality was monitored by the time required for trauma room treatment until the CT scan was performed and used as a surrogate marker. Inclusion criteria were patients aged 0-16 years, who were evaluated in a level 1 pediatric trauma room with an injury severity score (ISS) ≥8 and the necessity for a CT scan. RESULTS: Before (group 1) and after (group 2) implementation of iTRAPS 16 patients were included in each group. There were no significant differences between the age and the ISS in the two groups of patients. The required time for trauma room treatment was significantly reduced from an average of 33.6 min before to 15.2 min after implementation of iTRAPS (p < 0.01). DISCUSSION: The required time for the trauma care room treatment could be significantly reduced by more than half after the implementation of iTRAPS. The reasons were the interdisciplinary organization of the trauma room leadership, reorganization of patient transfer and improved briefing by emergency doctors. CONCLUSION: Besides a well-organized trauma team, it is essential that the trauma room workflow is adapted to the specific structure of the hospital. Despite the limitations of the study the data demonstrate that the trauma room workflow enables an efficient management. By the interdisciplinary reorganization of the pediatric trauma room treatment with improved structures and standardized processes, patient care was more effective with a significant reduction in the time required for trauma room treatment. The suggested iTRAPS concept could be used as a framework to establish individualized workflows for pediatric trauma room treatment in other hospitals. This algorithm should be supplemented by standardized operating procedures (SOPs) for the differentiated radiological diagnostic procedures in areas of traumatic brain injury (TBI), thoracic and abdominal trauma in children.

Closed reduction and immobilization of displaced distal radial fractures. Method of choice for the treatment of children?

PURPOSE: The therapy of distal radial fractures in children is expected to be as non-invasive as possible but also needs to deliver the definite care for gaining optimal reduction and stabilizing the fracture. Therefore, closed reduction and immobilization is competing with routine Kirschner wire fixation. The aim of our study was to investigate if closed reduction and immobilization without osteosynthesis can ensure stabilization of the fracture. METHODS: We chose a retrospective study design and analyzed 393 displaced distal radial fractures in children from 1 to 18 years with open epiphyseal plates studying medical files and X-rays. The Pearson's χ (2) test was applied. Statistical analysis was performed using IBM SPSS Statistics 20.0. Statistical significance was set at an alpha level of P = 0.05. RESULTS: Of these studied fractures 263 cases were treated with closed reduction and immobilization. Only 38 of these needed secondary interventions, 28 of these underwent reduction after redisplacement and ten patients received secondary Kirschner wire fixation. The last follow-up examination after 4-6 weeks revealed that 96.4% of fractures initially treated with closed reduction and immobilization were measured within the limits of remodeling. 104 of the studied fractures were treated with cast immobilization alone when displacement was expected to correct due to remodeling. Here 22.1% of patients needed secondary reduction. Furthermore, primary Kirschner wire fixation was performed in only 25 children with unstable fractures and only one received further treatment. Interestingly, operative reports of primary closed reduction revealed that repeated maneuvers of reduction as well as residual displacement are risk factors for redisplacement. CONCLUSION: For the treatment of displaced distal radial fractures in children closed reduction and immobilization can be considered the method of choice. However, for cases with repeated reduction maneuvers or residual displacement we recommend primary Kirschner wire fixation to avoid redisplacement. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

The level of preventive health care in an internal medicine residency clinic: still only an ounce of prevention?

BACKGROUND: Clinical prevention is a critical component of primary care residency training. How well residents do preventive services is one measure of the adequacy of their training. METHODS: To assess the level of preventive health care in a university internal medicine residency clinic, we conducted a randomized retrospective review of 225 patient records. RESULTS: We documented preventive services in only 39% of potentially appropriate instances. Cholesterol screening occurred in 53% of eligible cases, breast examination in 41%, mammogram in 69%, Papanicolaou's smear in 53%, estrogen replacement therapy (ERT) in 41%, fecal occult blood testing in 30%, flexible sigmoidoscopy in 18%, influenza vaccination in 65%, pneumococcal vaccination in 44%, and tetanus immunization in only 9%. Male residents were significantly less likely than females to order mammograms or offer ERT. CONCLUSIONS: Compared to earlier studies of similar design, we found that the level of preventive health care has improved during residency training, but remains unacceptably low.

MR imaging in children with dermatomyositis: musculoskeletal findings and correlation with clinical and laboratory findings.

OBJECTIVE: The purpose of this study was to describe the musculoskeletal MR findings in childhood dermatomyositis and to correlate MR findings with indicators of disease activity such as muscle strength and serum levels of muscle enzymes. SUBJECTS AND METHODS: This prospective study included 24 children: 19 children with dermatomyositis and five control subjects. The diagnosis of dermatomyositis was established by clinical findings and serum levels of muscle enzymes in all patients, electromyography in six patients, and biopsy in four patients. At the time of the initial MR evaluation, patients were classified on the basis of clinical findings as having active (n = 15) or inactive (n = 4) disease. A total of 44 MR evaluations of patients with dermatomyositis were included in the study: 19 initial MR examinations and 12 examinations repeated after 4-6 months of therapy in patients with active disease. An additional 13 examinations were performed on five patients. Conventional T1-weighted (SE 600/20) and T2-weighted (SE 2500/80) spin-echo and fat-suppressed MR images were obtained. The T2-weighted images (TE = 80) were used for comparison. In addition to the visual assessment, ratios between the signal intensity of muscles (gluteus, adductors, quadriceps, and hamstrings) and the signal intensity of subcutaneous fat in the same tomographic section were calculated. RESULTS: All patients with clinically active disease (n = 15) had abnormal findings on MR studies, whereas those with inactive disease (n = 4) had normal MR findings. Signal-intensity ratios of patients with active disease were greater than those in control subjects, whereas the ratios in patients with inactive disease were not different from those in control subjects. After 4-6 months of therapy, the average signal-intensity ratios of treated patients with repeated MR evaluations (n = 12) differed from ratios obtained before therapy in the same patients, but were not different from the ratios in control subjects. Other MR findings observed were perimuscular edema, enhancement of the chemical-shift artifact, and inflammatory changes of subcutaneous fat. Fat-suppressed imaging enhanced visualization of abnormalities. Markedly abnormal signal intensities of muscle were associated with marked elevations of serum levels of muscle enzymes; however, abnormal MR findings were visualized with normal serum levels of muscle enzymes. CONCLUSION: Findings of active childhood dermatomyositis on T2-weighted MR images include increased signal intensity in affected muscle, perimuscular edema, enhanced chemical-shift artifact, and increased signal intensity in subcutaneous fat. After therapy, signal intensity of muscle returns to normal. These MR findings are enhanced on fat-suppressed images.(ABSTRACT TRUNCATED AT 400 WORDS)

Elevated proliferating cell nuclear antigen levels in immature thymocytes. Dissociation from cell cycle progression.

Entry into and progression through the cell cycle is associated with a tightly regulated program of gene expression in mature T cells. One such gene product, proliferating cell nuclear Ag (PCNA), is the auxiliary protein of DNA polymerase delta, and is induced during late G1 and early S phase after stimulation of resting (G0) cells. Blockade of PCNA production has been found to inhibit cell division suggesting that PCNA plays an important role in cell proliferation. The extent to which PCNA and other proliferation-related gene products are similarly regulated in thymocytes has been largely undetermined. Here, we report that immature double positive (CD4+CD8+) thymocytes express high levels of PCNA protein and mRNA relative to mature single positive (CD4+CD8- or CD4-CD8+) thymocytes or peripheral blood T cells. Elevation of PCNA expression among double positive thymocytes is not the result of increased numbers of cycling cells in this subpopulation, being specifically observed in double positive thymocytes with normal diploid DNA content and resting (G0) levels of RNA. Unlike mature thymocytes and T cells, mitogenic stimulation did not induce an increase in PCNA expression in double positive thymocytes. These data indicate that immature thymocytes express high levels of PCNA in the absence of cell cycle progression, thus providing evidence for differential regulation of proliferation related pathways during lymphoid development. Altered expression patterns of these genes in immature vs mature thymocytes may contribute to the process of thymic selection.

Data base analysis of protein expression patterns during T-cell ontogeny and activation.

We have developed a data base of lymphoid proteins detectable by two-dimensional polyacrylamide gel electrophoresis. The data base contains two-dimensional patterns and derived information pertaining to polypeptide constituents of unstimulated and stimulated mature T cells and immature thymocytes, single-cell-derived T- and B-cell clones, leukemia cells, and lymphoid cell lines. Using this data base, we have compared the protein constituents of mature T cells and immature thymocytes before and after mitotic stimulation. A subset of polypeptides that are induced in mature T cells following mitotic stimulation were found to be constitutively expressed in immature thymocytes. Other polypeptides exhibited differences in their expression between mature and immature thymocytes in a manner unrelated to proliferation. The identity of several constitutively expressed or mitotically induced proteins in lymphoid cells was established by microsequencing. These initial findings point to significant differences in the molecular pathways leading to proliferation between mature and immature T cells. The construction of this database should facilitate further studies of lymphoid differentiation and function.

PCNA levels in neuroblastoma are increased in tumors with an amplified N-myc gene and in metastatic stage tumors.

N-myc oncogene amplification in neuroblastoma has been found to be significantly associated with advanced stage disease and tumor progression. However, there is a lack of data on tumors, regarding the relationship between N-myc gene amplification and proliferation activity. Proliferating cell nuclear antigen (PCNA) is a proliferation-induced 36 kD nuclear protein that is the auxiliary component of DNA polymerase delta. PCNA levels in tissues have been found to correlate with proliferative activity. We have examined PCNA levels in neuroblastomas in relation to N-myc gene amplification and tumor stage. Statistically, significantly higher levels of PCNA were observed in tumors with an amplified N-myc gene relative to tumors with a single gene copy. The highest levels of PCNA were observed in advanced stage tumors with an amplified N-myc gene. Treatment of neuroblastoma cells in culture with retinoic acid, which induces differentiation, resulted in a substantial decrease in PCNA. Our results suggest that PCNA levels may reflect differences in proliferative activity between neuroblastomas, related to stage of the disease and to N-myc gene copy number.

Differential expression of Op18 phosphoprotein during human thymocyte maturation.

Op18 (also termed prosolin/stathmin) is a highly conserved 18-kD cytosolic phosphoprotein expressed in low levels in mature resting G0 lymphocytes, but induced in late G1 and S phases after entry into the cell cycle. In addition to its induction in normal proliferating lymphocytes, Op18 has been found to occur at high levels in acute leukemias and in neuroendocrine tissue. The presence and rapid phosphorylation of Op18 after stimulation of proliferating cells correlates with subsequent functional responses of the cells, and, therefore, Op18 has been suggested to play a key role in signal transduction. The pattern of expression of Op18 during lymphoid development is of interest in view of its high levels of expression in acute leukemias, representing cells arrested at an immature stage, thus raising the possibility that Op18 may be regulated differently in mature and immature lymphoid cells. We report here that immature human thymocytes bearing the cortical double positive phenotype (CD4+CD8+) constitutively express high levels of Op18 protein. In contrast, in mature single positive thymocytes (CD3+CD4+ or CD3+CD8+), Op18 protein is expressed at a lower level, comparable to that seen in peripheral blood T cells. Cell cycle analysis demonstrated that most of the cells in the double positive thymocyte population expressing high levels of Op18 were noncycling and arrested in G0. Furthermore, there was no correlation between Op18 levels and the proportion of cycling cells in double positive thymocyte populations isolated from different thymuses. Interestingly, although Op18 protein levels did not increase any further after mitogenic stimulation of double positive thymocytes, an increase in Op18 phosphorylation was observed, thus coupling of Op18 phosphorylation to cell activation remained intact. Our results show that during lymphoid maturation Op18 expression is uncoupled from cell proliferation. These data also suggest that the ordered expression of proliferation-associated genes seen in mature T cells may be disrupted during T cell maturation.

Activation of resting peripheral blood lymphocytes through the T cell receptor induces rapid phosphorylation of Op18.

Op18 is a highly conserved major cytosolic phosphoprotein that has been implicated in signal transduction in a wide variety of cell types. Freshly isolated peripheral blood lymphocytes (PBL) constitutively express low levels of mostly unphosphorylated Op18. After mitogenic stimulation of PBL, Op18 synthesis is induced at a time when cells are entering S-phase. In this study, we have examined the phosphorylation of Op18 in freshly isolated PBL after activation of the T cell receptor by OKT3. Quantitative analysis of Op18 phosphorylation was undertaken by metabolic labeling with 32Pi and PhosphorImager analysis of two-dimensional gels. After 10 or 15 min of activation by OKT3, one of the three major phosphorylated forms of Op18, designated Op18c, increased approximately 10-fold, which represented a most pronounced change among a large number of phosphoproteins analyzed. In time course experiments, increased Op18 phosphorylation to yield Op18c was observed as early as 2 min. Continued OKT3-induced activation for 20 to 72 h resulted in a further increase in phosphorylated Op18 forms, which paralleled new Op18 synthesis and occurred at a time when cells were entering S-phase, as determined by [3H]-thymidine incorporation. Inhibitors of lymphoid proliferation, cyclosporin A and RPM, had no effect on early (less than 15 min) phosphorylation. Addition of calphostin C, a specific inhibitor of protein kinase C, 1 min prior to stimulation of resting T cells with OKT3 completely inhibited further phosphorylation of Op18. Incubation of PBL with calphostin C for 75 min decreased constitutive levels of phosphorylated Op18. In contrast, inhibition of cyclic nucleotide-dependent protein kinases with HA1004 had no effect on Op18 phosphorylation. Activation of cAMP-dependent protein kinase with Forskolin or 8Br-cAMP did not increase Op18 phosphorylation. Our results suggest that Op18 phosphorylation is mediated by protein kinase C activation as an early event in T cell activation through the T cell receptor.

Proliferation-related expression of p19/nm23 nucleoside diphosphate kinase.

High level expression of the nm23-H1 gene, which encodes for a nucleoside diphosphate kinase, has been found to correlate with diminished metastasis in some tumors but not in others. We have previously identified the protein product of the nm23-H1 gene in two-dimensional electrophoretic gels and have designated it p19/nm23. In neuroblastoma, higher levels of p19/nm23, which are associated with amplification of the N-myc oncogene, large tumor mass, and metastasis, were observed in advanced stage tumors compared with limited stage disease. Because of the variable expression of nm23-H1 in different tumors, we have investigated the relationship between amounts of the protein and cell proliferation. The levels of p19/nm23 were compared between resting and mitotically stimulated normal human PBLs and in leukemia cells. The amount of p19/nm23 increased in normal lymphocytes in response to mitotic stimulation and paralleled the increase in DNA synthesis. In leukemia cells obtained from patients with different subtypes of acute leukemia, p19/nm23 levels were also increased relative to resting normal lymphocytes. Treatment of mitotically stimulated lymphocytes with cyclosporin, which inhibits proliferation, blocked the increase in p19/nm23; treatment of the leukemia cell line HL-60 with dimethylsulfoxide, which induces terminal differentiation, resulted in diminished levels of p19/nm23. Our data therefore provide evidence that nm23-H1 expression is related to cell proliferative activity.

Fat-suppressed MR imaging of myositis.

A hybrid fat-suppression sequence in magnetic resonance (MR) imaging was used to evaluate inflammatory muscle disorders in seven children: five patients with dermatomyositis, one patient with vasculitis, and one patient with viral myositis. Fat-suppressed multisection axial images obtained with the same repetition and echo times as those used to obtain standard spin-echo (SE) images enabled direct comparison of images, with little variation of T1 and T2 weighting. In six patients, the contrast on images obtained with T2 fat suppression was 15%-20% greater than contrast on conventional T2-weighted SE images. In all seven patients, the subjective judgment was that T2-weighted fat-suppression sequences improved visualization of muscle abnormalities. It is concluded that T2 fat suppression is useful in evaluation of inflammatory muscle disorders in children because it increases contrast and eliminates fat as a cause of muscle abnormality.

Serial magnetic resonance imaging in juvenile dermatomyositis.

Magnetic resonance imaging (MRI) was used to follow the course of juvenile dermatomyositis from the onset of disease through resolution of a primary relapse. The signal intensity of the T2-weighted image of involved muscles was elevated during periods of disease activity, and returned to approximately normal levels with effective suppression of disease activity. T1-weighted images of involved muscles remained approximately normal despite disease activity.

Highly resolving two-dimensional gels for protein sequencing.

Two-dimensional (2D) PAGE, using carrier ampholytes for the first-dimension separation, has provided a tool for the simultaneous analysis of cellular proteins. To extend the utility of 2D PAGE to the preparative level, we have investigated the use of immobilized pH gradients (IPG) for the first-dimension separation. The results we have obtained indicate that as much as 1 mg of cellular protein can be loaded onto a single IPG gel without loss of resolution. Mutant polypeptides previously detected in carrier ampholyte-based 2D gels were equally detectable in IPG-based 2D gels. With IPG gels several hundred cellular polypeptides can be isolated, from as few as 10 gels, in sufficient amount for sequencing with current sequencing technology. We therefore conclude that IPG greatly enhances the prospects for the large-scale sequencing of cellular proteins for the development of 2D gel-related protein data bases and for the identification of new polypeptide gene products, with the attendant implications for a genome sequencing effort.

High levels of p19/nm23 protein in neuroblastoma are associated with advanced stage disease and with N-myc gene amplification.

The gene encoding a novel protein designated nm23-H1, which was recently identified as identical to the A subunit of nucleotide diphosphate kinase from human erythrocytes, has been proposed to play a role in tumor metastasis suppression. We report that untreated neuroblastoma tumors contain a cellular polypeptide (Mr = 19,000) designated p19, identified in two-dimensional electrophoretic gels, which occurs at significantly higher levels (P = 0.0001) in primary tumors containing amplified N-myc gene. The partial amino acid sequence obtained for p19 is identical to the sequence of the human nm23-H1 protein. An antibody to the A subunit of erythrocyte nucleotide diphosphate kinase reacted exclusively with p19. In this study, significantly higher levels of p19/nm23 occurred in primary neuroblastoma tumors from patients with advanced stages (III and IV) relative to tumors from patients with limited stages (I and II) of the disease. Even among patients with a single copy of the N-myc gene, tumors from patients with stages III and IV had statistically significantly higher levels of p19/nm23 than tumors from patients with stages I and II. Our findings indicate that, in contrast to a proposed role for nm23-H1 as a tumor metastasis suppressor, increased p19/nm23 protein in neuroblastoma is correlated with features of the disease that are associated with aggressive tumors. Therefore, nm23-H1 may have distinct if not opposite roles in different tumors.

Magnetic resonance imaging appearance of the muscles in childhood dermatomyositis.

Documentation of muscle involvement in a child thought to have dermatomyositis may require the performance of invasive procedures such as electromyography and/or muscle biopsy. We describe four patients with dermatomyositis in whom magnetic resonance imaging (MRI) demonstrated the muscle involvement. The involved muscles had increased signal intensity on the T2-weighted images (SE 2500/80) and normal appearance on the T1-weighted images (SE 600/20). The involvement of the muscles was not uniform. There was good correlation between the distribution of muscle involvement by MRI and functional testing. Follow-up MRI scans in patients with favorable outcome demonstrated that the affected muscles had returned to normal signal intensity. Although the MRI findings are not specific, in the proper clinical context they may be helpful in establishing the diagnosis of dermatomyositis. MRI may also be used in establishing an appropriate muscle biopsy site. In addition, MRI may be used for monitoring the progress of the disease.