Ingrid Kerckaert

3D Computerized Model for Measuring Strain and Displacement of the Brachial Plexus Following Placement of Reverse Shoulder Prosthesis

The aim of the present study was to develop a method for three‐dimensional (3D) reconstruction of the brachial plexus to study its morphology and to calculate strain and displacement in relation to changed nerve position. The brachial plexus was finely dissected and injected with contrast medium and leaden markers were implanted into the nerves at predefined places. A reverse shoulder prosthesis was inserted in a cadaveric specimen what induced positional change in the upper limb nerves. Computed tomography (CT) was performed before and after this surgical intervention. The computer assisted image processing package Mimics® was used to reconstruct the pre‐ and postoperative brachial plexus in 3D. The results show that the current interactive model is a realistic and detailed representation of the specimen used, which allows 3D study of the brachial plexus in different configurations. The model estimated strains up to 15.3% and 19.3% for the lateral and the medial root of the median nerve as a consequence of placing a reverse shoulder prosthesis. Furthermore, the model succeeded in calculating the displacement of the brachial plexus by tracking each implanted lead marker. The presented brachial plexus 3D model currently can be used in vitro for cadaver biomechanical analyses of nerve movement to improve diagnosis and treatment of peripheral neuropathies. The model can also be applied to study the exact location of the plexus in unusual upper limb positions like during axillary radiation therapy and it is a potential tool to optimize the approaches of brachial plexus anesthetic blocks. Anat Rec, 291:1173‐1185, 2008.

Peroxisomes (microbodies) in human liver: cytochemical and quantitative studies of 85 biopsies.

The number, intracellular distribution, and staining characteristics of human hepatocellular peroxisomes that had been made visible by cytochemical staining for catalase were evaluated in biopsies from 75 patients with hepatic, inflammatory, or malignant disease and ten normal individuals. Intensity of staining was found to be proportional to enzymatic activity by microspectrophotometry. Scanning transmission electron microscopy (STEM) image analysis demonstrated an inverse relationship between peroxisomal size and contrast. Peroxisomes were more abundant, and often concentrated in a perinuclear configuration in cholestatic and cirrhotic livers. Decreased peroxisomal staining was common in cholestasis, cirrhosis, hepatitis, and in almost all patients with malignancies, both with and without hepatic metastases.

Biogenesis of peroxisomes in fetal liver

Peroxisomes are single membrane‐limited cell organelles that are involved in numerous metabolic functions. Peroxisomes do not contain DNA; the matrix and membrane proteins are encoded by the nuclear genome. It is assumed that new peroxisomes are formed by division of existing organelles. The present article gives an overview of microscopic studies and recent unpublished results dealing with peroxisome biogenesis in mammalian fetal liver and presents data on peroxisomes in oocytes.

Ultrasonic Assessment of Mucosal Thickness around Implants: Validity, Reproducibility, and Stability of Connective Tissue Grafts at the Buccal Aspect

PURPOSE (1) To assess validity and reproducibility of mucosal thickness (MT) registration by means of an ultrasonic device and (2) to determine the MT stability of connective tissue grafts (CTGs) when applied at the buccal aspect of single implants demonstrating alveolar process deficiency. MATERIALS AND METHODS For the validity assessment, four human cadaver edentulous maxillae were used to determine MT at 100 different sites. Soft tissue thickness as recorded with the ultrasonic device was compared with MT as registered with Micro-CT (UGent, Ghent, Belgium), taking the latter as gold standard. For the reproducibility assessment, 50 duplicate ultrasonic registrations were used. For the clinical part, 10 non-smoking patients with a single implant were included. All demonstrated alveolar process deficiency and had been provided with a provisional screw-retained crown at the time of inclusion. Following an intrasulcular incision at the buccal aspect, a CTG was inserted to thicken soft tissues. MT was assessed at t0 (before CTG), t1 (immediately after CTG), t2 (suture removal), t3 (permanent crown installation), and t4 (9 months after CTG). RESULTS There was a strong correlation between ultrasonic and Micro-CT measurements (r = 0.89, p < .001). However, the former significantly underrated MT by 0.13 mm (p = .030). There was a strong correlation between duplicate ultrasonic recordings (r = 0.99, p < .001). Seven females and three males were included in the clinical study with a mean age of 52. MT significantly increased by 0.92 mm between t0 and t1 (p = .005). Between t3 and t4, there was a slight, yet significant decrease of 0.15 mm (p = .047). CONCLUSION The ultrasonic device can be used as a non-invasive, reliable, and reproducible method to evaluate MT. Using this technology around single implants demonstrated that CTG may substantially thicken the peri-implant mucosa with acceptable stability over a 9-month period.

Isolated dihydroxyacetonephosphate-acyl-transferase deficiency in rhizomelic chondrodysplasia punctata : clinical presentation, metabolic and histological findings

AbstractRhizomelic chondrodysplasia punctata (RCDP) is clinically characterized by symmetrical shortening of the proximal limbs, contractures of joints, a characteristic dysmorphic face, and cataracts. In the classical form an impairment of several peroxisomal functions and enzymes (plasmalogen synthesis, phytanic acid oxidation, 3-oxoacyl-CoA thiolase) has been repeatedly shown. Recently a variant involving only the peroxisomal dihydroxyacetonephosphate acyltransferase (DHAP-AT) has been described. We present a patient with isolated DHAP-AT deficiency and all clinical, radiological, and pathological features of classical RCDP. For the first time, microscopy and immunocytochemistry of hepatocytes could be performed.ConclusionIn contrast to studies on classical rhizomelic chondrodysplasia punctata which have shown enlarged peroxisomes in numbers varying from hepatocyte to hepatocyte, the peroxisomes in our patient seem to be normal in size, number and shape.

Peroxisome mosaics in the liver of patients and the regulation of peroxisome expression in rat hepatocyte cultures

Peroxisomal deficiency disorders, which are genetically transmitted, are assumed to be expressed in all cells, and the use of cultured skin fibroblasts for diagnosis and research is based on this assumption. We describe four unrelated patients, three boys and a girl, with clinical, biochemical and microscopic evidence of a peroxisomal disorder whose livers display mosaicism, that is, parenchymal cells with peroxisomes are adjacent to cells without peroxisomes. After discussing the possible origin of these mosaics, we examine the influence of the environment on the expression of peroxisomes in adult rat hepatocytes in primary monolayer and three-dimensional culture. In this model the expression of peroxisomes varies between cells and depends upon the culture conditions.

Practical guide for morphometry of human peroxisomes on electron micrographs.

Morphometry of peroxisomes is performed on electron micrographs of ultrathin sections after staining for catalase activity with diaminobenzidine; specific peroxisomal labelling is preferred to guarantee recognition. Peroxisomal number, size, axial ratio and volume parameters are determined and compared to control values. Results from 19 patients with loss of peroxisomal functions are listed. In many patients alterations in peroxisomal morphometric features are found. A brief guideline for interpreting morphometric data is included. Diagnostically relevant morphometric alterations are summarized.

An Anatomically Validated Brachial Plexus Contouring Method for Intensity Modulated Radiation Therapy Planning

PURPOSE To develop contouring guidelines for the brachial plexus (BP) using anatomically validated cadaver datasets. Magnetic resonance imaging (MRI) and computed tomography (CT) were used to obtain detailed visualizations of the BP region, with the goal of achieving maximal inclusion of the actual BP in a small contoured volume while also accommodating for anatomic variations. METHODS AND MATERIALS CT and MRI were obtained for 8 cadavers positioned for intensity modulated radiation therapy. 3-dimensional reconstructions of soft tissue (from MRI) and bone (from CT) were combined to create 8 separate enhanced CT project files. Dissection of the corresponding cadavers anatomically validated the reconstructions created. Seven enhanced CT project files were then automatically fitted, separately in different regions, to obtain a single dataset of superimposed BP regions that incorporated anatomic variations. From this dataset, improved BP contouring guidelines were developed. These guidelines were then applied to the 7 original CT project files and also to 1 additional file, left out from the superimposing procedure. The percentage of BP inclusion was compared with the published guidelines. RESULTS The anatomic validation procedure showed a high level of conformity for the BP regions examined between the 3-dimensional reconstructions generated and the dissected counterparts. Accurate and detailed BP contouring guidelines were developed, which provided corresponding guidance for each level in a clinical dataset. An average margin of 4.7 mm around the anatomically validated BP contour is sufficient to accommodate for anatomic variations. Using the new guidelines, 100% inclusion of the BP was achieved, compared with a mean inclusion of 37.75% when published guidelines were applied. CONCLUSION Improved guidelines for BP delineation were developed using combined MRI and CT imaging with validation by anatomic dissection.

Hepatic peroxisomes in isolated hyperpipecolic acidaemia: evidence supporting its classification as a single peroxisomal enzyme deficiency

Abstract Hyperpipecolic acidaemia is still regarded as a peroxisomal assembly deficiency. The enzyme responsible for the accumulation of pipecolic acid is located in the peroxisomes in man. We studied the appearance and alterations of peroxisomes in liver biopsy material from three unrelated children suffering from isolated hyperpipecolic acidaemia, in which only the metabolism of pipecolic acid is disturbed, using light and electron microscopy after cytochemical staining for visualisation of peroxisomes. Morphometric results showed the presence of normal-sized to small peroxisomes, an increase in number and abnormally shaped organelles, suggesting enhancement of metabolic efficiency. In one case enlarged organelles were observed. Skin fibroblasts were studied in all patients: their peroxisomes appeared to be normal. The obvious presence of peroxisomes in isolated HPA indicates that this disorder should be classified as a single peroxisomal enzyme deficiency.

Asymmetry of the ULNT1 elbow extension range-of-motion in a healthy population: Consequences for clinical practice and research

OBJECTIVES To investigate the effect of isolated muscular variance, side and hand dominance on elbow-extension range-of-motion (EE-ROM) of the median nerve upper limb neurodynamic test (ULNT1). This study analyzes these variables potential to influence ULNT1 EE-ROM symmetry and the possible consequences for clinical practice and research. STUDY DESIGN Controlled laboratory study, cross-sectional. BACKGROUND No normative data exist to interpret correctly EE-ROM. Clinical interpretation is based on bilateral comparison. This procedure assumes natural EE-ROM symmetry, with lack of scientific evidence. METHODS Nineteen participants with Langers axillary arch (LAA), a muscular variant bridging the brachial plexus, were selected from 640 healthy volunteers, together with a matched control group. ULNT1 EE-ROMs were measured using the Vicon(®) optoelectronic system. RESULTS A full mixed model revealed no significant effects on EE-ROM for LAA and the variable side. Significant differences were found in EE-ROM between dominant and non-dominant sides (standard ULNT1 test position: 2.84° ± 1.60°, p = 0.0004; ULNT1 with differentiating maneuver: 3.05° ± 1.98°, p = 0.003). Approximately 30% of the subjects showed clinically detectable restriction (≥10°) of the dominant side EE-ROM. CONCLUSION Hand dominance is significantly associated with restriction of EE-ROM, which results in a clinically detectable asymmetry. This compromises the clinical procedure of comparing the patients EE-ROM to the opposite side. Erroneous conclusions could result in side to side analyses, if the effect is not taken into account in neurodynamic research.