The multiple-scattering series in few-nucleon systems

We discuss under which circumstances the resummation of the multiple-scattering series is justified from an EFT point of view. The application to πd and K̅d scattering is briefly discussed.

Advances and challenges in skeletal muscle angiogenesis.

The role of capillaries is to serve as the interface for delivery of oxygen and removal of metabolites to/from tissues. During the past decade there has been a proliferation of studies that have advanced our understanding of angiogenesis demonstrating tissue capillary supply is under strict control during health, but poorly controlled in disease - resulting in either excessive capillary growth (pathological angiogenesis) or losses in capillarity (rarefaction). Given that skeletal muscle comprises nearly 40% of body mass in humans, skeletal muscle capillary density has a significant impact on metabolism, endocrine function, and locomotion, and is tightly regulated at many different levels. Skeletal muscle is also high adaptable, and thus one of the few organ systems which can be experimentally manipulated (e.g. by exercise) to study physiologic regulation of angiogenesis. This review will focus on 1) the methodological concerns that have arisen in determining skeletal muscle capillarity, and 2) highlight the concepts that are reshaping our understanding of the angio-adaptation process. We also summarize selected new findings (physical influences, molecular changes and ultrastructural rearrangement of capillaries) that identify areas of future research with the greatest potential to expand our understanding of how angiogenesis is normally regulated, and that may also help to better understand conditions of uncontrolled (pathologic) angiogenesis.

Acute hemorrhagic edema of young children: a concise narrative review

Acute hemorrhagic edema of young children is an uncommon but likely underestimated cutaneous leukocytoclastic vasculitis. The condition typically affects infants 6-24 months of age with a history of recent respiratory illness with or without course of antibiotics. The diagnosis is made in children, mostly nontoxic in appearance, presenting with nonpruritic, large, round, red to purpuric plaques predominantly over the cheeks, ears, and extremities, with relative sparing of the trunk, often with a target-like appearance, and edema of the distal extremities, ears, and face that is mostly non-pitting, indurative, and tender. In boys, the lesions sometimes involve the scrotum and, more rarely, the penis. Fever, typically of low grade, is often present. Involvement of body systems other than skin is uncommon, and spontaneous recovery usually occurs within 6-21 days without sequelae. In this condition, laboratory tests are non-contributory: total blood cell count is often normal, although leukocytosis and thrombocytosis are sometimes found, clotting studies are normal, erythrocyte sedimentation rate and C-reactive protein test are normal or slightly elevated, complement level is normal, autoantibodies are absent, and urinalysis is usually normal. Experienced physicians rapidly consider the possible diagnosis of acute hemorrhagic edema when presented with a nontoxic young child having large targetoid purpuric lesions and indurative swelling, which is non-pitting in character, and make the diagnosis either on the basis of clinical findings alone or supported by a skin biopsy study.

Acute hemorrhagic edema of young children (cockade purpura and edema): a case series and systematic review

BACKGROUND: Acute hemorrhagic edema is an uncommon leukocytoclastic small-vessel vasculitis of young children. OBJECTIVE: To determine clinical features and outcome of acute hemorrhagic edema of young children. METHODS: Seven new cases are reported. A search of the literature revealed 287 published cases. RESULTS: The 294 children (boys, 67%) ranged in age between 2 and 60 months (median, 11 months) and were in good general condition. In 195 children the disease developed after a simple acute infection. The exanthemata included large, round, red to purpuric plaques predominantly over the cheeks, ears, and extremities and mostly tender edema of the distal extremities, ears, and face. Involvement of body systems other than skin was rare. The children recovered spontaneously without sequelae. LIMITATIONS: Results of this review must be viewed with an understanding of the limitations of the analysis process, which incorporated data exclusively from single case reports or case series. CONCLUSIONS: Acute hemorrhagic edema of young children is a very benign vasculitis. Physicians might rapidly develop the skills necessary to diagnose this condition.

In vivo biochemical 7.0 Tesla magnetic resonance: preliminary results of dGEMRIC, zonal T2, and T2* mapping of articular cartilage

INTRODUCTION: Ultra-high-field whole-body systems (7.0 T) have a high potential for future human in vivo magnetic resonance imaging (MRI). In musculoskeletal MRI, biochemical imaging of articular cartilage may benefit, in particular. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and T2 mapping have shown potential at 3.0 T. Although dGEMRIC, allows the determination of the glycosaminoglycan content of articular cartilage, T2 mapping is a promising tool for the evaluation of water and collagen content. In addition, the evaluation of zonal variation, based on tissue anisotropy, provides an indicator of the nature of cartilage ie, hyaline or hyaline-like articular cartilage.Thus, the aim of our study was to show the feasibility of in vivo dGEMRIC, and T2 and T2* relaxation measurements, at 7.0 T MRI; and to evaluate the potential of T2 and T2* measurements in an initial patient study after matrix-associated autologous chondrocyte transplantation (MACT) in the knee. MATERIALS AND METHODS: MRI was performed on a whole-body 7.0 T MR scanner using a dedicated circular polarization knee coil. The protocol consisted of an inversion recovery sequence for dGEMRIC, a multiecho spin-echo sequence for standard T2 mapping, a gradient-echo sequence for T2* mapping and a morphologic PD SPACE sequence. Twelve healthy volunteers (mean age, 26.7 +/- 3.4 years) and 4 patients (mean age, 38.0 +/- 14.0 years) were enrolled 29.5 +/- 15.1 months after MACT. For dGEMRIC, 5 healthy volunteers (mean age, 32.4 +/- 11.2 years) were included. T1 maps were calculated using a nonlinear, 2-parameter, least squares fit analysis. Using a region-of-interest analysis, mean cartilage relaxation rate was determined as T1 (0) for precontrast measurements and T1 (Gd) for postcontrast gadopentate dimeglumine [Gd-DTPA(2-)] measurements. T2 and T2* maps were obtained using a pixelwise, monoexponential, non-negative least squares fit analysis; region-of-interest analysis was carried out for deep and superficial cartilage aspects. Statistical evaluation was performed by analyses of variance. RESULTS: Mean T1 (dGEMRIC) values for healthy volunteers showed slightly different results for femoral [T1 (0): 1259 +/- 277 ms; T1 (Gd): 683 +/- 141 ms] compared with tibial cartilage [T1 (0): 1093 +/- 281 ms; T1 (Gd): 769 +/- 150 ms]. Global mean T2 relaxation for healthy volunteers showed comparable results for femoral (T2: 56.3 +/- 15.2 ms; T2*: 19.7 +/- 6.4 ms) and patellar (T2: 54.6 +/- 13.0 ms; T2*: 19.6 +/- 5.2 ms) cartilage, but lower values for tibial cartilage (T2: 43.6 +/- 8.5 ms; T2*: 16.6 +/- 5.6 ms). All healthy cartilage sites showed a significant increase from deep to superficial cartilage (P < 0.001). Within healthy cartilage sites in MACT patients, adequate values could be found for T2 (56.6 +/- 13.2 ms) and T2* (18.6 +/- 5.3 ms), which also showed a significant stratification. Within cartilage repair tissue, global mean values showed no difference, with 55.9 +/- 4.9 ms for T2 and 16.2 +/- 6.3 ms for T2*. However, zonal assessment showed only a slight and not significant increase from deep to superficial cartilage (T2: P = 0.174; T2*: P = 0.150). CONCLUSION: In vivo T1 dGEMRIC assessment in healthy cartilage, and T2 and T2* mapping in healthy and reparative articular cartilage, seems to be possible at 7.0 T MRI. For T2 and T2*, zonal variation of articular cartilage could also be evaluated at 7.0 T. This zonal assessment of deep and superficial cartilage aspects shows promising results for the differentiation of healthy and affected articular cartilage. In future studies, optimized protocol selection, and sophisticated coil technology, together with increased signal at ultra-high-field MRI, may lead to advanced biochemical cartilage imaging.